120th Advisory Committee on Nuclear Waste (ACNW) Meeting, July 27, 2000
UNITED STATES OF AMERICA
NUCLEAR REGULATORY COMMISSION
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ADVISORY COMMITTEE ON NUCLEAR WASTE
120TH ACNW MEETING
***
Nuclear Regulatory Commission
Room T2B3
Two White Flint North
11545 Rockville Pike
Rockville, Maryland
Thursday, July 27, 2000
The Commission met in open session, pursuant to
notice, at 8:31 a.m., THE HONORABLE DR. B. JOHN GARRICK,
Chairman of the Committee, presiding.
MEMBERS PRESENT:
DR. JOHN B. GARRICK, Chairman
DR. GEORGE W. HORNBERGER, Vice Chairman
DR. RAYMOND G. WYMER
MR. MILTON N. LEVENSON. STAFF AND PARTICIPANTS:
DR. JOHN T. LARKINS, Executive Director, ACRS/ACNW
MR. HOWARD LARSON, Acting Associated Director, ACRS/ACNW
MR. RICHARD K. MAJOR,, ACNW Staff
MS. LYNN DEERING, ACNW Staff
MR. AMARJIT SINGH, ACNW Staff
DR. ANDREW C. CAMPBELL, ACNW Staff
MR. MEDHAT EL-ZEFTAWY, ACRS Staff
ROBERT A. NELSON, NMSS, Division of Waste Management, NRC
JOHN T. BUCKLEY, NMSS
STUART A. RICHARDS, Office of Nuclear Reactor Regulation,
Division of Licensing and Project Management, NRC
LARRY W. CAMPER, NMSS, Division of Waste Management
CHERYL TROTTIER, Office of Nuclear Regulatory Research,
Division of Risk Analysis and Applications
TOM L. FREDRICHS, Office of Nuclear Regulatory Research,
Division of Licensing and Project Management, NRC
WILLIAM R. OTT, Office of Nuclear Regulatory Research,
Division of Risk Analysis and Applications, NRC
PHILIP D. MEYER, U.S. Department of Energy, Pacific
Northwest National Laboratory
GLENDON W. GEE, U.S. Department of Energy, Northwest Pacific
National Laboratory
SLOMO P. NEUMAN, University of Arizona, Tucson
PETER J. WIERENGA, University of Arizona, Tucson. C O N T E N T S
ITEM PAGE
OPENING STATEMENT 216
STATUS OF THE NRC'S DECOMMISSIONING PROGRAM 217
HYDROLOGY RESEARCH 281 . P R O C E E I N G S
[8:31 a.m.]
CHAIRMAN GARRICK: Good morning. The meeting will
now come to order.
This is the third day of the 120th meeting of the
Advisory Committee on Nuclear Waste. This meeting will be
open to the public, and today the Committee will hear an
overview from the NRC Staff on the Decommissioning Program.
We will review a project by NRC's Office of
Nuclear Regulatory Research on Hydrogeological Model
Development and Parameter Uncertainty; continue our
preparation of ACNW reports; and finally discuss matters
related to the conduct of Committee activities and matters
and specific issues that were not completed earlier.
Howard Larson is the Designated Federal Official
for the initial portion of today's meeting. This meeting is
being conducted in accordance with the provisions of the
Federal Advisory Committee Act. We have received no written
statements or requests to make oral statements from members
of the public regarding today's session. Should anyone wish
to, please notify a member of the staff.
It is requested that each speaker use a
microphone, identify themselves, and speak clearly and
loudly.
We're going to hear about the Decommissioning
Program, as I said, but what's of great interest to the
Committee today is that we're going to get an overview of
the entire program. This might be the first time we've done
that.
And Ray Wymer, the Committee Member that's our
expert in this area will take the lead in the questioning
and discussions.
DR. WYMER: Thanks, John. He has already put me
on thin ice now by calling me an expert.
[Laughter.]
DR. WYMER: This is part of the meeting I have
been looking forward to, actually. We're going to have a
discussion, I think, of the integration of the three parts
of the D&D program.
We've heard about the site decommissioning
management plan a number of times, and we've heard about the
license termination plan, and we've heard about the modeling
studies, all separately.
Now it's my understanding that we're going to hear
it in an integrated fashion, and I'm interested to see if
the whole is greater than the sum of the parts, or whether
the integration is really just the three parts again.
Bob Nelson, I think, is going to lead off here,
and I trust he will introduce the succeeding speakers, so
let's commence.
MR. NELSON: Thank you. Good morning. My name is
Bob Nelson. I'm Chief of the Facilities Decommissioning
Section in the Decommissioning Branch of the Division of
Waste Management.
Joining me today in this presentation are Stu
Richards, Project Director for Decommissioning, Office of
Nuclear Reactor Regulation; and John Buckley of my section.
We welcome the opportunity to discuss the
Decommissioning Program with the Committee. This briefing
is intended to provide the Committee with the status of the
Decommissioning Program.
A similar status report was provided to the
Commission in SECY 00-094, dated April 25th of this year.
The presentation based largely on that paper, with some
added information.
Copies of the paper and this presentation are in
the rear of the room for the members of the public.
The Staff will provide a briefing to the
Commission on the Program on October 23rd.
The function of the Decommissioning Program is to
regulate the decontamination and decommissioning of material
and fuel cycle licensees, power reactors and non-power
reactors, resulting in the ultimate goal of license
termination.
A broad spectrum of activities is associated with
this program, as described in Attachment 1 to the Commission
paper. In meeting the briefing objectives stated here, we
will discuss each of these principal activities.
This slide just provides a brief summary of the
Decommissioning Program that I will describe in more detail
in subsequent portions of this presentation.
On July 21st, 1997, the NRC published its final
rule on radiological criteria for license termination,
commonly called the License Termination Rule as Subpart E to
10 CRF Part 20.
NRC regulations require that materials licensees
submit decommissioning plans to support decommissioning of
their facility, if such is required by a license condition,
or the procedures and activities necessary to carry out the
decommissioning have not been approved by NRC, and these
procedures could increase the potential public health and
safety impacts on workers or the public.
NRC regulations also require that reactor
licensees submit post-shutdown decommissioning activity
reports, commonly referred to as PSDARs, and license
termination plans for LTPs to support the decommissioning of
nuclear power facilities.
The Staff is currently developing guidance for the
Staff and for licensees to use in reviewing and developing
these plans and other information submitted by licensees to
support decommissioning of their facilities.
Some of the more importance guidance documents are
listed on this slide. A more complete listing is supplied
in Attachment 15 to the SECY.
Since there are some acronyms used here on the
slide, I'll point out that MARSSIM, as you are probably
aware, is the Multi Agency Radiological Site Survey and
Investigation Manual, and Reg Guide 1.179 is the Standard
Format and Content Guide for license termination plans.
Material and fuel cycle decommissioning activities
include regulatory oversight of the site decommissioning
management plan sites and other complex decommissioning
sites; implementing the Commission's direction under
Directive-Setting Initiative 9, by initiating a pilot study
for performing decommissioning without submittal of a
decommissioning plan;
Undertaking license termination file reviews;
performing financial assurance reviews; providing West
Valley oversight; interacting with EPA and ISCORS,
inspecting SDMP and other complex decommissioning sites;
Maintaining the computerized risk assessment and
data analysis lab or CRADL; and Office of Nuclear Regulatory
Research providing data and models to support performance
assessments.
You can see that we have a rather complex program
encompassing those elements. We also have extensive
interactions with other agencies, and some of those are
listed here on the slide.
I'll discuss West Valley a little later in the
presentation, so I won't dwell on it here. ISCORS are the
Interagency Steering Committee on Radiation Standards, and
we work extensively with EPA through ISCORS, principally, to
resolve issues related to regulation of radionuclides.
This interaction is necessary to avoid unnecessary
duplication of regulatory requirements. Principal ISCORS
activities are carried out through its subcommittees which
report back to the full ISCORS Committee at its quarterly
meetings.
The current Subcommittees include Risk
Harmonization, Mixed Waste, Recycle or Clearance,
Decommissioning/Cleanup, NORM, and Sewer Reconcentration.
ISCORS produces an annual report, NUREG 1707. The
1990 report is currently in publication and should be
available soon.
ISCORS also maintains a website at ISCORS.org for
members of the public to have access.
The principal activity currently going on now with
the EPA is the negotiation of a Memorandum of Understanding
concerning the two agencies' interaction regarding cleanup
of sites. That activity is currently ongoing, and the MOU
has not been finalized at this point.
In addition, the Staff has been interfacing
extensively with EPA Region I regarding the review of
license termination plans submitted by Maine Yankee. We
anticipate similar interactions with our review of the
Connecticut Yankee Haddam Neck LTP which we have just
received.
Similar to our support of the development of the
MARSSIM or Multi Agency Radiological Survey and Site
Investigation Manual, we are participating in an interagency
working group that is developing MARLAP, or the Multi Agency
Laboratory Accreditation Program.
Finally, we routinely work with various state
public health and safety organizations, other federal
agencies, and tribal organizations in conjunction with our
safety and environmental reviews of decommissioning plans,
license termination plans, and other license submittals.
I'd like to introduce John Buckley, who will
discuss our oversight of SDMP and complex decommissioning
cases and our terminated license review. John?
MR. BUCKLEY: Thanks, Bob. Good morning. My name
is John Buckley.
As Bob mentioned earlier, one of the main
activities in materials decommissioning is oversight of the
SDMP and otherwise complex decommissioning sites programs.
As indicated on Slide 7, there are currently 29
SDMP sites or complex sites; 26 of those 29 are actually
SDMP sites; three are complex decommissioning sites.
Twenty-three of the 29 sites have already
submitted decommissioning plans. The Staff has reviewed and
approved 13 of the 23 decommissioning plans which we have
received. Of the 29 sites, the Staff expects that by the
time we get all DPs in hand, 11 of the sites will request
restricted release.
DR. WYMER: These are all reactors?
MR. BUCKLEY: No, these are material and fuel
cycle facilities.
And 11 of the 29 current sites may be transferred
to Agreement States by the Year 2002. One site will go to
Minnesota, possibly, and ten to Pennsylvania. To date, the
Staff has removed 31 sites from the SDMP.
Detailed information on the current 29 sites in
presented in Attachments 3, 4, 5, and 7 of the Commission
paper, so if you need additional information, that's the
place to look.
In 1990 the staff began a review of all previously
terminated license files to assure that the licenses were
properly terminated and that the sites posed no threat to
public health and safety or the environment.
NRC contracted with Oak Ridge National Laboratory
to conduct this review. Oak Ridge reviewed approximately
37,000 terminated license files.
Of the 37,000 files reviewed, regional inspectors
have verified that 38 sites are contaminated with limits
above the unrestricted release limits. A listing of the
contaminated sites and their decommissioning status is
presented in Attachment 6 of SECY-94.
The regions have almost completed their review of
all the terminated license sites. Approximately 120 sites
are left for review by the regions. Of those, 29 are loose
material sites and approximately 92 are sealed source sites.
I will turn this presentation back over to Bob.
MR. NELSON: Do you have any questions on those
two slides before we move on?
DR. WYMER: How many reactors are there, just the
two that are --
MR. NELSON: We will get into those.
MR. BUCKLEY: The reactors come later. This is
just the materials.
DR. WYMER: Okay.
DR. HORNBERGER: What is a loose material site?
MR. BUCKLEY: I'm sorry?
DR. HORNBERGER: Loose material.
MR. BUCKLEY: It is a nonsealed source. Anything
-- everything not a sealed source is a loose material.
DR. CAMPBELL: I have a question. What was the
release limit you used, is it the new LTR 25 millirem limit?
In other words, did they do an analysis of these 38 sites to
determine that they exceed 25 millirem? This says above
unrestricted release limit. The unrestricted release limit
is 25 millirem.
MR. BUCKLEY: But it has changed. So some of
these sites were released prior to --
DR. CAMPBELL: So this is the old standard.
MR. BUCKLEY: Some are under the old standard,
some are under the new standard. Attachment, if you look at
Attachment 3, it will provide you an indication of which
criteria is being used.
MR. NELSON: To the SECY, Attachment 3.
MR. BUCKLEY: Correct.
MR. NELSON: To the SECY.
DR. CAMPBELL: So some of them, they actually did
assessments and determined that the amount of material on
the site would exceeded 25 millirem?
MR. BUCKLEY: Correct.
DR. CAMPBELL: And then some of them you used so
many picocuries per gram contamination levels that were the
old standard?
MR. BUCKLEY: Correct.
DR. HORNBERGER: And the sites with 25 millirem,
these were basically field surveys that demonstrated that
they exceed, or was it a computation?
MR. BUCKLEY: I think what the regions did, and I
don't want to speak for them, but they went out and did
field surveys. If they found something that looked like it
was beyond twice, three times background, then they flagged
it.
MR. NELSON: Any other questions before we move
on?
[No response.]
MR. NELSON: The staff continues to implement the
Commission's direction under Direction Setting Issue for
DSI-9. There are three facilities currently in the pilot
program, as identified on this slide. The purpose of the
pilot program was to look at, exam the feasibility of
licensees performing decommissioning without a prior
approved decommissioning plan.
The pilot study was approved by the Commission in
a staff requirements memorandum dated June 30th, 1998. We
last reported to the Commission on this topic in
SECY-99-160, dated June 22nd, 1999.
We plan to meet with each of these licensees this
fall to determine how well they have done, where they are in
their cleanup and what lessons we could learn from this
activity, and provided a status report to the Commission in
January.
For example, the first site, the Westinghouse pump
repair facility in Cheswick, is nearing completion of its
activities, and they plan to submit a final survey report
and request for release of portions of their site very soon.
The other sites, I don't have a current status on, but we
will be getting that as we move towards our fall meeting.
Another aspect of our decommissioning program is
review of financial assurance. The staff routinely reviews
financial assurance submittals for materials and fuel cycle
facilities and maintains a financial assurance instrument
security program. This entails review of decommissioning
cost estimates, as well as the financial assurance
instrument, whether it be a letter of credit, a standby
trust agreement, et cetera, to verify that the instrument
meets our requirements, could be executed if necessary, and
that the cost estimate is reasonable for the activities
anticipated. Routinely, between 40 and 60 financial
assurance submittals are reviewed each year.
Also, under this area we are consolidating our
financial assurance guidance which has consisted of a
standard format and content guide, Reg. Guide 3.66, and a
Standard Review Plan for decommissioning financial assurance
submittals, NUREG-1337. The consolidation of these
documents will be into our new decommissioning Standard
Review Plan so that we have fewer guidance, individual
guidance documents on the street, and most of the guidance
will be contained within the Standard Review Plan, a module
and an appendix to that plan, that we briefed you on, I
believe earlier in the year.
NRC's decommissioning responsibilities for the
West Valley Demonstration Project and the West Valley site
are specified under the West Valley Demonstration Project
Act. Presently this activity includes prescribing
decontamination and decommissioning criteria, reviewing
draft portions of the EIS for decommissioning, and closure
of the site, reviewing safety analysis reports prepared by
DOE, and performing periodic onsite monitoring of project
activities and records to assure radiological health and
safety.
The Commission's draft policy statement regarding
decommissioning criteria for the West Valley Demonstration
Project and the West Valley site was issued in December 1999
for public comment. The draft policy statement specified
NRC's license termination rule as decommissioning criteria.
We are currently reviewing comments received both from a
public meeting, as well as written comments, and are
preparing a follow-on submittal to the Commission.
It is currently the staff's plan to brief you in
more depth on this in your October meeting, at which time we
will have prepared a submittal to the Commission. We will
discuss that with you at that time.
In addition, we have developed a Commission paper
on stakeholder involvement, because of the many stakeholders
and complexities of that activity, and that is currently in
its final stages of management review. It should be going
to the Commission shortly as an information paper.
The Office of Nuclear Regulatory Research
continues to provide data and models to NMSS to support
assessments of public exposure to environmental releases of
radioactive material from site decommissioning.
Research has provided NMSS with data on
radionuclide solubilities that will be used to assess
releases from ore-processing slag; data on degradation of
archeological slags that will be used to assess the
long-term performance of slags as a source of radioactive
contamination.
As you may be aware, many of our SDMP sites
processed ore containing radioactive material, and as a
result have large amounts of contaminated slag onsite.
We will also produce guidance on characterization
of decommissioning sites containing these slags, and provide
documentation on unsaturated zone monitoring strategies for
use in review of monitoring proposals for licensing actions
concerning decommissioning and waste disposal facilities in
unsaturated media.
We assisted in the development of technical bases
to support selection of site-specific parameter values for
estimating flux and transport in dose assessment codes.
We are developing a probabilistic version of the
computer code, RESRAD, and modification of the Sandia
decision support system to allow multidimensional
groundwater pathway analyses.
Now, I'm going to move into the reactor
decommissioning area, and I'll provide an overview of the
NMSS involvement, and then I will turn this presentation
over to Stu Richards, who will discus NRR activities.
From the NMSS side, reactor decommissioning
includes our project management of technical review
responsibility for decommissioning two power reactors. NRR
has project management and licensing oversight for 17
decommissioning reactor facilities.
The program also includes implementation of the
plan developed in response to Commission Direction-Setting
Initiative Number 24; development of standardized technical
specifications for decommissioning; conduct of core
inspections and project management for all licensed,
non-power reactors.
NMSS has project management and technical review
responsibility for the Firm I and Peach Bottom Unit I power
reactors; NRR has project managing and licensing oversight
for 17 power plants that have either submitted DPs or their
equivalent, or PSDARS.
We have Attachment 11 and 12 to the SECY paper
which provide status information on each of these plants.
The NMSS principal activities in support of
reactor decommissioning are summarized on this slide.
[Pause.]
Technical reviews of license termination plans are
currently underway for Maine Yankee, Trojan, and Saxton. An
acceptance review is in progress for the Connecticut Yankee
license termination plan.
NMSS has supported public meetings for the first
three, and will provide similar support for Connecticut
Yankee.
In addition, we will be conducting confirmatory
radiological surveys at these plants in support of the
license termination process. Such surveys are currently
scheduled in August for the Maine Yankee and Trojan plants.
Project management responsibilities for the Peach
Bottom and Fermi plants for NMSS have been limited to
processing minor amendment requests. It currently does not
represent a major workload for us.
In the guidance development area, NMSS has
recently published -- finalized and published NUREG 1700,
the Standard Review Plan for License Termination Plans, and
we are supporting NRR in development of a variety of
guidance documents related to decommissioning.
Are there any questions on that before I turn the
presentation over to Stu Richards?
[No response.]
MR. RICHARDS: Good morning. Can you hear me all
right? I'm Stu Richards. I'm the NRR Branch Chief
responsible for the decommissioning power reactors. I'm
also responsible for the operating reactors in Region IV.
I'd like to talk a little bit about what NRR does,
and hopefully clarify this integration function here. Just
a little bit of background:
When a power reactor shuts down -- well, let me
back up. The rules are written for reactors to shut down
with some forewarning, so the rules are written such that a
plant enters the normal end of life but recognize they're
going to go through decommissioning, and they have time to
plan for it, and go through a normal process.
Unfortunately, virtually all the reactors that are
presently in decommissioning, didn't get there that way.
They found themselves in some kind of a problem and ended up
going into decommissioning on fairly short notice. So
there's a little bit of a disconnect between the experience
we've had to date and the way it's supposed to really
happen.
Hopefully that will change in the future, but when
a plant does enter the decommissioning phase of operation,
the first thing they want to do is, they want to make the
transition from an operating facility to a decommissioning
facility.
And that is primarily NRR's role in the
decommissioning activities. We have the front end, we take
the plant from an operating unit into decommissioning, and
really NMSS has got the back end when it comes time to
terminate the license and determine what to do with the rad
waste. That's their end of the business, and there's a lot
of work in between where I think we both do a lot of work
together. So I spend a lot of time talking to Larry Camper
and Bob Nelson, and we actually are, I think, pretty well
integrated.
There is a lot of transition right now in the
decommissioning world. And I'll try and give you a little
flavor of what's going on, and then hopefully answer your
questions.
Again, the primary interest of plants that enter
decommissioning is to get rid of all those operating reactor
rules that apply, because, you know, when they shut down,
they still have a full Part 50 license that applies to that
facility.
The way it has worked in the past is that
licensees have had to come in to NRR and request amendments
to their tech specs or to get exemptions from the Part 50
requirements that they don't think should apply to a
decommissioning plant. That entails a lot of paperwork and
analysis on their part, and also takes up a lot of the
Staff's time to review all that work and to issue approvals.
We've been doing that on a site-by-site,
case-by-case basis, so it's quite work-intensive.
About a year ago or year and a half ago, we
thought, hey, it's time to stop trying to do that. Let's
look at putting together what we call the integrated
rulemaking and try and put together a process where plants
can go through that phase and get relief from operating
reactor requirements without having to provide us with
paperwork and analysis and without us having to review it;
just put it in the regulations.
In order to take that step, we felt we needed a
single, solid technical basis for backing up these
regulatory changes. So we put together a technical working
group to take a look specifically at the risks of storing
spent fuel onsite in the spent fuel pool.
And that study has been going on now for a little
over a year. That group came out with a draft report early
this year. We got comments back from the ACRS, from a
number of public stakeholders, and from the industry, and
those comments are trying to be resolved with a date of
August the 31st to come out with the final risk report.
But the idea here is that the primary event of
consideration is the zirconium fire in the spent fuel pool.
If somehow you drain all the water out and you get the fuel
to start to burn, you have a very significant event, because
you don't have a containment building; you can have multiple
cores; you have a real problem.
On the other hand, the probability of that event
occurring is very, very, very small. The draft report said
it was less than three times ten to the minus six; at this
point we can't say that's incredible and take it off the
table, but it's pretty close to that.
So, at any rate, that's a little bit of background
on what we're doing. The integrated rulemaking, the slide
lists the five areas we're looking at.
What we did is, we picked out three or four of
these areas as areas where the industry felt they could get
immediate financial relief, if we could do something to make
that transition easier for them.
Emergency preparedness, safeguards, and insurance,
cost the industry a lot of money, and they feel that when
they shut the plant down, they should no longer have to meet
the operating reactor requirements that incur those
expenses.
So we're taking a hard look at those three. The
backfit, if you go to the backfit rule for decommissioning
plants -- or, actually, the backfit rule, period -- it's
really written for operating reactors, and if you put on a
legal hat, you could say this rule doesn't apply to
decommissioning plants; it's not written that way.
Decommissioning plants felt like they should have
the same protections as an operating reactor on the backfit
rule, and the Commission told us to treat them the same, and
then when we get around to it, to put into the rule, so
that's why that's there.
And then operator training and staffing, again,
when a plant shuts down, they still have all the training
programs and staffing requirements of a Part 50 license.
You know, they want to get away from that, they want to
transition to the minimum staffing they need in order to
basically maintain the spent fuel pool.
So, we have put together a rulemaking plan. We
submitted that to the Commission at the end of June. That
is SECY 001-45, I believe. That paper is now public,
although the Commission has not voted on it.
We asked specifically that we be allowed to
release it to the public in order to get prompt feedback.
So we are waiting for direction from the Commission on how
to proceed on that.
The second major bullet on the slide talks about
regulatory improvements, and what we're talking about here
is, beyond the first five issues that we were looking at, we
wanted to -- or we proposed to the Commission to take a look
at all regulations in Part 50 that apply to decommissioning
reactors, and our proposal is to modify all those
regulations in some form so that we have one section of the
regulations that applies to decommissioning plants.
As it presently stands, you know, you're searching
through Part 50, trying to figure out, hey, what in here
applies to me now that I'm shut down? So we thought that it
would be proper to try and bring those altogether into one
place.
We owe the Commission more information on that by
September 15th of this year, and there's a resource issue
there of whether that's the right approach to take.
The industry has a different view on these two
items. They have recently come in with a letter to us that
said we think you ought to do this in one shot, just put it
into one rulemaking, and they felt that we could do the
whole thing in 24 months.
Personally, I disagree with that. I think that's
unrealistic to think that we can overhaul all the
decommissioning regulations in 24 months.
And I feel that, you know, if you take that route,
you end up with everything being held hostage to whatever
the one hardest issue is.
So we had a workshop earlier this week with the
industry out on the West Coast and challenged them to make
sure they are asking for what they really want because if
they want it as one package it is likely to drag on longer
than 24 months.
On the other hand, there are no reactors right now
that appear to be entering the decommissioning phase, so you
can argue that what is the rush?
The next bullet talks about the generic
Environmental Impact Statement for decommissioning. That
was last done in 1988 and we are doing an update on that.
We are working closely with the Environmental Protection
Agency and the industry. I might note that specifically
this update is going to consider entombment, rubbelization,
and partial site release, which is selling off pieces of
land before the plant actually enters the decommissioning
phase, or the final license termination phase.
We are also responsible for guidance documents.
Bob talked about some of the ones that NMSS is doing. We
provide guidance documents for the post-shutdown
decommissioning activities report.
When a plant enters the decommissioning phase one
of the first things they are required to do is to put
together this overview document that describes what they
intend to do in the future as far as decommissioning the
facility. We also provide guidance to the inspectors. It
talks about a handbook for the inspectors that we are
putting together and various NUREGs.
One I would like to mention is that we do put
together a Frequently Asked Questions NUREG that we find to
be very helpful. We have a lot of public meetings and it is
nice to be able to hand out a book that says, hey, here's a
lot of the questions you might ask and has the answers in
it.
We are also responsible for the Decommissioning
Inspection Program while the facility is under the
responsibility of NRR and work with the regions to define
that program to make sure it is implemented properly.
Bob mentioned it before, but just to make sure it
is clear, we have a memorandum of understanding between NRR
and NMSS and what it says is that NRR is the Project Manager
for the facility until all the fuel is out of the spent fuel
pool. When it goes to either offsite, which right now it
isn't doing, or it goes to dry storage, at that point NRR
transfers responsibility for project management to NMSS, so
again on the big picture we are primarily concerned with the
facility entering decommissioning and making that transition
to truly a decommissioning facility, getting them through
the changes in the tech specs and the regulations.
NMSS of course is focused on what to do with the
waste, final surveys and license termination. There is a
lot of overlap there and we do spend a lot of time talking
together about it.
Flipping on to the next slide, the next slide
is really just a status of facilities, the power reactor
facilities that have entered decommissioning, twenty-one
reactors between 1963 and 1998. Two have completed decon
and dismantlement. That's Fort St. Vrain and Shoreham. We
have got six that are undergoing active decon and
dismantlement, nine that have chosen the safe store route
where they are going to let the facility sit for awhile
before they decide what to do with it, and we have four
facilities that have a combination of storage and then
decontamination and dismantlement.
That completes the two slides I have.
DR. WYMER: What actually constitutes going into
decommissioning? If two have completed decon and
dismantlement and if Maine Yankee is now coming in to talk
to you about the two, are they not entering decommissioning?
What does that mean?
MR. RICHARDS: Well, the two are the two that have
had their licenses terminated.
DR. WYMER: That's already done. Okay.
MR. RICHARDS: The six -- let me back up to the
options. You can -- when you shut the facility down you can
enter SAFESTOR, basically bottle the facility up and let it
sit, you have to complete the process within 60 years, or
you can enter direct and active decon and dismantlement of
the facility, such as Maine Yankee is doing.
DR. WYMER: That isn't entering decommissioning?
MR. RICHARDS: Yes, that is. All of these are
entering decommissioning.
DR. WYMER: Oh, I thought you said earlier none
were entering decommissioning.
MR. RICHARDS: No, no, no, no. I'm sorry.
DR. WYMER: Oh -- no new ones. Okay.
MR. RICHARDS: This is a summary of these 21
reactors. The idea here is we have got some that shut down
and enter decommissioning, active decommissioning, taking
the facility apart right away.
We have got a number of facilities that shut down
and elected to put the plant into a SAFESTOR condition.
DR. WYMER: Okay.
MR. RICHARDS: And we have got some that have a
combination of both.
DR. WYMER: I thought I heard you say no reactors
are entering the decommissioning phase.
MR. RICHARDS: No, I'm sorry, I meant no new
reactors are on the horizon. We don't have any reactors
right now that are operating that we know are scheduled to
enter decommissioning.
DR. WYMER: Okay.
MR. RICHARDS: That is because of the deregulation
of the industry and I think the license renewal and the
purchase of facilities.
DR. WYMER: Okay, my apologies.
CHAIRMAN GARRICK: Isn't the whole issue of the
schedule for a repository and the success of dry cask
storage, for example, going to have a major impact on what
constitutes decommissioning and the transition, say, between
NRR and NMSS?
Well, supposing Yucca Mountain doesn't come about
and simultaneously that dry cask storage works out to the
satisfaction of everybody and the public picks up on this as
the solution, at least for the time being, and the time
being could be 100 years or so -- that would change things a
whole lot, would it not?
MR. RICHARDS: Well, actually, right now I think
both the industry and the NRC are carrying out their
business based on the assumption that facilities are going
to use the dry cask storage option simply because even I
guess on the present schedule Yucca Mountain is pretty far
out in the future.
CHAIRMAN GARRICK: Yes.
MR. RICHARDS: There are a large number of
operating reactors that already have dry storage. There are
a number of decommissioning plants that either have it or
are moving in that direction. There seems to be a
recognition that if you want to get on with decommissioning,
the thing to do is to license a dry storage facility under
Part 72 and then just decommission the rest of your facility
and get rid of the Part 50 license so all you have left is a
dry storage ISFSI facility with maybe a very small staff of
people care of it, and, you know, I am just speculating that
it appears --
CHAIRMAN GARRICK: What if somebody comes along
and says, look, since we are in a dry cask storage mode and
we have fuel onsite, we would like to take advantage of the
fact that this is a high level waste storage site and store
other kinds of waste onsite that would be beyond the 25 MR.
Are these kinds of proposals feasible?
MR. RICHARDS: If there is somebody here from the
Spent Fuel Project Office, it might be best for them to
answer, but I know there's facilities that are planning on
storing the greater than Class C waste --
CHAIRMAN GARRICK: Right.
MR. RICHARDS: -- in dry storage casks with the
spent fuel actually.
CHAIRMAN GARRICK: Right.
MR. RICHARDS: As far as the low level waste, in
order to terminate the license, they have to get that
material offsite and meet the 25 millirem ALARA criteria, so
again in order to terminate your Part 50 license you have to
decontaminate, remediate the site to that license
termination rule criteria, but you can rid of the Part 50
license and still have your dry storage over here separate.
CHAIRMAN GARRICK: I guess what I am asking is a
realistic appraisal of the situation. Does it suggest that
quite possibly a lot of these will not get out from under
Part 50?
MR. RICHARDS: Well, they have that option. They
can still --
CHAIRMAN GARRICK: But you don't have a sense of
how this might play out as far as --
MR. RICHARDS: Right now I think most facilities
plan to go dry storage with a Part 72 license that are in
active decommissioning, trying to terminate their license.
They are going to decontaminate the site to the
license termination rule criteria, terminate the Part 50
license, and you will be left with dry storage under Part
72. I think that is what they are doing.
Larry, am I wrong on that?
MR. CAMPER: No, I think you are right. There are
also economic incentives to do that too, because of the
different categories of licensing.
I mean one of the things that prompts a movement
from an operating facility to a facility in decommissioning
is a categorical change in licensing fee, so that is clearly
a motivator.
As Stu has said, the trend is a movement toward
isolated storage onsite because of the high level waste
repository problem. There will be probably a storage of
greater than Class C but beyond that, no.
I think frankly any movement or any move by the
industry to store waste other than that or to collect waste
from other sites would probably not -- certainly would not
be met with political receptivity and would pose a number of
challenges for us as well.
I think what you are seeing now is what you are
going to see for the foreseeable future.
The other thing that is interesting too, and as
Stu mentioned, we just came back from a conference at NEI
out on the West Coast, and there was a time when we were
anticipating more reactors moving into decommissioning than
we are. We can see, of the ones listed up here, we can see
four more out there coming -- Humboldt Bay, SONGS I, Yankee
Rowe coming back, and Big Rock Point. Those are the ones we
look out and project that might be coming along in terms of
staff work for decommissioning per se.
CHAIRMAN GARRICK: That is the big thing that's
changed over the last couple of years --
MR. CAMPER: Exactly.
CHAIRMAN GARRICK: -- is that license renewal
expectation has gone from 4 or 5 percent up to maybe 80
percent or 85 percent.
MR. CAMPER: Absolutely and of course the industry
is very excited about that, as you might expect.
CHAIRMAN GARRICK: Right.
MR. CAMPER: But I think what you are seeing now
is what you are going to see certainly for the foreseeable
future in terms of how isolated storage is being handled.
The Yucca Mountain Repository question, you know,
who knows?
CHAIRMAN GARRICK: Okay. Thank you.
MR. LEVENSON: Can I ask a somewhat general
question, since we are on the idea that you have a crystal
ball and can look ahead?
Do you have any perception -- the U.S. is spending
a fair amount of money to subsidize silo storage of spent
fuel in the former Soviet Union countries as something that
is significantly cheaper than dry cask storage.
Do you have any perception that might be coming
into the U.S. picture?
It initiated here. It's what has been done at the
EBR-2 Reactor for 30 years.
MR. CAMPER: I can't comment on that. I don't
know enough about that trend to comment whether that will
ever materialize.
MR. LEVENSON: You have heard no discussions?
MR. CAMPER: No, I am not aware of any.
MR. NELSON: I apologize for not introducing my
Branch Chief, Larry Camper, Chief of the Decommissioning
Branch, Division of Waste Management.
MR. CAMPER: We know each other.
[Laughter.]
MR. NELSON: Moving on, as a result of our recent
organization, NMSS Environmental Review responsibilities
fall under the Environmental and Performance Assessment
Branch of the Division of Waste Management. However, those
activities are budgeted under the decommissioning program,
so I am including them here to provide a complete
description of our budgeted program.
The activities in the environmental review area
include preparation and review of Environmental Impact
Statements, or EISs, review of Environmental Assessments
prepared by the Staff.
Presently it is estimated that EISs will be
prepared for the following SDMP and complex decommissioning
sites -- the U.S. Army Jefferson Proving Ground; Dow
Chemical Company; SCA Services; Michigan Department of
Natural Resources; Mallinckrodt Chemical; Shield Alloy
Metallurgical Corporation; Fan Steel; Kaiser Aluminum;
Sequoyah Fuels Corporation; the Babcock & Wilcox Shallow
Land Disposal Area; The Moly Corp., Incorporated Washington,
Pennsylvania facility; and Whitaker Corporation.
Three of these have already submitted
decommissioning plans for restricted release. They are Fan
Steel, Sequoyah Fuels, and Moly Corp Washington.
It is our practice to develop an EIS for all
restricted release submittals.
The others that I mentioned we anticipate either
are or may submit a decommissioning plan calling for
restricted release.
The Branch will also prepare an EIS -- I should
say that of the three -- Fan Steel, Sequoyah Fuels, and Moly
Corp. Washington -- the Sequoyah Fuels' EIS is under
development, the draft EIS.
The Branch will also prepare an Environmental
Impact Statement for the West Valley site.
Environmental assessments must be prepared for
most other licensing actions including approval of DPs
involving unrestricted release for SDMP and complex
decommissioning sites.
The Environmental and Performance Assessment
Branch reviews all the EAs that we develop.
That's all I plan on saying about that activity.
Are there any questions in that area?
DR. WYMER: Just a comment. There is going to be
an awful lot of restricted release sites around the country,
and mostly it is the horizon that you can see to is 100 or
200 years, something like that. And the question comes up
of, how about after that, you know? What sort of plans or
safeguards or what is in place to make sure -- I know that
you have financial assurance considerations and you have
various governmental involvements that have to be in place,
if that is appropriate? But, still, the horizon seems close
compared to the duration of the risk. Can you say anything
about how comfortable you feel about that or what -- how it
is handled?
MR. NELSON: Well, we are just -- restricted
release is certainly a new approach to decommissioning. We
haven't done a restricted release, completed a restricted
release approval under the License Termination Rule. So, in
some respects, we are learning as we go.
I need to point, though, restricted release is
that. Our regulatory oversight would cease at the time we
terminated the license. So there would not be, for example,
inspections. There would not be reports from the licensee
to us for review. We would have to be satisfied that the
licensee's plan for restricted release met all of our
requirements and that we could -- and met the License
Termination Rule such that we could cease regulatory
oversight of the site.
DR. WYMER: That is the crux of the problem right
there. How do you make yourself comfortable with the fact
that everything has got to be okay after you turn it loose?
MR. NELSON: Well, to some extent the same way we
-- to some extent, exactly the same way we do for
unrestricted release. The dose limit is different but we
still have to do a very similar assessment for restricted
release. Of course, there are differences, but the
similarities are that we have to do -- we have to assess the
dose assessment performed by the licensee and conclude that
the resulting dose is a reasonable estimate of the dose.
Whether that is above 25 or below 25, the analysis approach
is largely the same.
The real difference that we need to look at are
the institutional controls and financial assurance that are
put in place to keep the dose under 25. That is the big
difference. We haven't reviewed one of those before. And
so we have developed some guidance in the Standard Review
Plan, but that is going to be a significant area of our
review. In fact, we believe it is so significant that we
will focus our review for those cases on financial assurance
and institutional controls before we begin the technical
review.
We plan to do a phased review for restricted
releases so that we can satisfy ourselves that those
requirements, that we have some confidence that those
requirements were met before we go into a significant
expenditure for technical review.
I don't know if I can get more specific on what we
were looking for in a -- I think that the real, I don't
think is as much the cost estimate. I think we can
reasonably estimate cost. The question is, what mechanisms
would we authorize other than, say, a transfer to DOE for
long-term oversight? What other mechanisms might we
consider for institutional control?
MR. LARSON: That is on our agenda for October.
MR. NELSON: Yes.
MR. LARSON: And you can get a sense of Ray's
interest in this topic.
MR. NELSON: Larry.
MR. CAMPER: Let me just add one thing to that. I
was going to comment on this later. Getting back to your
question about the integration of all these activities. We
have the restricted release scenario in the regulations, and
it requires certain criteria, long-term durable controls,
responsible third parties and things of this nature, as well
as design considerations that go out beyond the timeframe
that you were mentioning. But in all of this, what is
emerging for us, we think is a big problem is finding, is
for these licensees to identify a responsible third party
that will be in this for the long haul.
As a result of that, the staff is working on two
things. One is we have had previously, and are currently
finalizing working arrangements with the Department of
Energy where DOE would be a cooperating agency on the
Environmental Impact Statements for these restricted release
scenarios. That is something that there were some exchanges
that went on between the two agencies back two or three
years ago. Now, some of these sites, Sequoyah Fuels, for
example, is at a point where it is time for the DOE to
emerge in that role. We are working that issue.
But, secondly, and more importantly, and I think
this kind of gets back to your integration comment really,
one of the largest challenges we face in decommissioning is
to ensure that we find viable third parties that will
oversee these sites for the long haul. We are finding that
while the regulations currently have what we think is a very
good mechanism in terms of institutional controls defined
within them, for licensees to find a responsible third party
to step up, whether it be a state government, a local
government or even a private entity is problematic. And,
therefore, we have grave concerns, as I think I pick up from
your question as to, what can do this in terms of long-term
stewardship?
There is a mechanism under 151(b) of the '82 Act,
the Nuclear Waste Policy Act, that allows sites to be
transferred to DOE. We will be talking more about that in
your October meeting. But we are starting to --
DR. WYMER: Transferring to DOE doesn't --
MR. CAMPER: I'm sorry?
DR. WYMER: Transferring to DOE doesn't change the
nature of the problem at all, it just gets it out of your
backyard.
MR. CAMPER: Well, what it does do, though, is it
provides a mechanism for long-term stewardship. I mean I
think our regulations, in terms of the dose criteria, the
requirements that have to be in place for a restricted
release scenario to occur, are sound. The issue I think,
though, is who will be that third party for the long haul?
DR. WYMER: Yes.
MR. CAMPER: DOE, of course, is structured to do
that. They have the infrastructure, and they have a
stewardship program that would seem to be ideal.
DR. WYMER: It is embryonic at the moment, but
they do have one.
MR. CAMPER: Right. So, we think that that is a
pathway that needs to be explored more aggressive with DOE.
And the staff has had a number of management level
discussions with DOE managers about that. There will be
communications that will take place between the two
organizations in the near future. So that is an area where
we think, in terms of the big picture, and the overall
integration of activities, that is a key part of that
puzzle.
DR. WYMER: That helps. Thanks.
MR. LEVENSON: Let me just ask a nit question
about that. Is it to DOE or is it to the legal entity of
the federal government, since there's motions afoot to
dismantle DOE?
MR. CAMPER: Well, I wouldn't begin to comment on
what is going to happen DOE as far as anything of
dismantlement. I can only tell you that right now, we are
working to solve and make sure that the institutional
controls, you know, methodology currently set forth in our
regulation, the LTR, that DOE seems at this point in time,
under its stewardship program, to be a viable pathway.
Now, there are conditions for those transfers.
And I dare say that DOE will be concerned that all those
conditions are met, no cost to the government, for example,
on those conditions. But as far as the long-term prognosis
for DOE, I couldn't --
MR. LEVENSON: No, I wasn't asking that. I was
just asking whether the transfers is legally to the federal
government, or specifically to DOE?
MR. CAMPER: It is to DOE under 151(b) of the '82
Act.
DR. WYMER: Thanks, Larry. That helps.
Sorry. Go ahead.
MR. NELSON: That's all right.
Any other questions on that topic?
[No response.]
MR. NELSON: I would like to move on then to some
of the efforts that we have taken and plan to undertake to
enhance the effectiveness and efficiency of the program. I
will provide a more detailed description of the streamlining
and rebaselining initiatives in a few minutes. But over the
past few years, we have also placed a significant emphasis
on guidance development to assist licensees in complying
with the License Termination Rule and to aid the staff in
providing consistent and efficiency review of licensee
submittals. Examples of this activity include the
Decommissioning Standard Review Plan and the License
Termination Plan Standard Review Plan.
In the next fiscal year we plan to conduct a
complete review of all decommissioning guidance and
consolidate that guidance as required.
To support these efforts, we have conducted a
variety of public workshops over the past year-and-a-half as
input for our guidance development effort and we plan to
continue to do so. An additional workshop, for example, is
planned in November.
In support of our efficiency and effectiveness
initiative, we have implemented the streamlining objectives
summarized on this slide. Further, the staff is
incorporating strategies to achieve performance goals that
the agency has set in its strategic planning process.
Examples include focusing on resolving key issues such as
institutional controls for restricted release, which we just
discussed in some depth. Other focus areas include partial
site release and rubblization, for example.
We conduct stakeholder workshops to seek licensee
and industry and public input, and we have ongoing efforts
to enhance our Standard Review Plans to make ourselves more
efficient.
In September of '99, the division began to
rebaseline the materials decommissioning program to
determine the current status of each SDMP and complex
decommissioning site, and to develop a comprehensive,
integrated plan for successfully bringing these sites to
closure.
To facilitate planning, site status summaries were
prepared as of the end of -- or as of December 31st, '99,
and these were developed for each SDMP and complex site.
These summaries for each site are included as an attachment
to the Commission paper.
These summaries indicate the status of each site
and identify the technical and regulatory issues that could
impact the removal of the site from the SDMP or the
completion of decommissioning.
For those licensees that have submitted a DP, we
have developed a schedule based on that submittal. For
those licensees that have not submitted a DP, we have also
developed schedules, but those schedules are based on
information that is currently available to the staff and the
decommissioning approach we anticipate the licensee to take.
The comprehensive plan includes identification of
all the major milestones associated with management of the
site. We have done that using project management software
and have produced an integrated Gantt chart for each site.
An example of one such chart is included in the SECY, but
the charts exist for all sites, and we are managing to those
milestone charts.
In addition, for the License Termination Plan
reviews that we are receiving, we are doing similar --
developing similar schedules and managing to those
schedules.
The program is not without its challenges. We
have talked about some of them today.
The License Termination Rule is a dose-based rule,
and one of the challenges is to assess the dose from a
released site. To assist in that effort, we've developed a
technical basis document for dose modeling that is included
in our Standard Review Plan for Decommissioning.
And the intent of that is, again, to provide
guidance to both the licensees and the staff on an
acceptable approach to do dose assessments. That should go
a long way to assist us in that effort.
But even with that guidance, it's new to a lot of
our staff. We have for many years, released sites under the
SDMP Action Plan, which didn't really require dose
assessment, so getting our staff up to speed, trained in
doing this, is going to be a challenge for us.
The release of solid materials is equally a
challenge. We don't have a consistent regulatory basis for
releasing material.
We use guidance that we have developed, and this
issue is clearly before the Commission, and until we have a
rule of some type, we will still have to use what guidance
we have, and often do a case-by-case review of licensee
requests to release solid material.
We've talked already about restricted release
cases and I'm not going to dwell any more on that unless you
have additional questions.
Under the topic of innovative performance-oriented
approaches, it's important to note that the rule -- that our
License Termination Rule is a performance-based rule, and
that licensees are going to find and propose innovative ways
to meet that rule.
Things such as rubblization is an example. We can
anticipate similar approaches or other approaches in the
future that we're going to have to address. These are not
cookbook solutions, and will require some effort by the
staff to review.
Partial site releases: Again, under the SDMP
action plan criteria where you have set numbers you have to
meet, it was an easy determination that you had cleaned up a
site and therefore could release it.
We now have a dose-based rule, and you have to
look at a partial site release, and one of the questions
that arises is, to what extent does the site that you
propose to release contribute to the dose on the site that
still is under license?
So that --
DR. WYMER: Or vice versa?
MR. NELSON: Or vice versa, exactly. And, of
course, finality, with the ongoing disagreement between the
Agency and the EPA over acceptable decommissioning criteria,
finality remains a question that the licensees have to
consider in their decommissioning approach.
Just one final word before I conclude the formal
presentation: You asked about integration of the program.
You've heard all the pieces described here.
To assist in that integration, we have formed the
Decommissioning Management Board which meets every two
weeks. It consists of appointed members from the Offices,
NMSS, NRR, Research. OCG attends, and these meetings have
set agendas, issues that are brought up before the Board
receive a coordinated review.
An example is Standard Review Plan for
Decommissioning. Each one of the modules of the Standard
Review Plan was reviewed by the Board before it was
published.
This Board, as I mentioned, I think, very
effective in providing the integration needed and the
guidance needed to the staff on addressing these issues.
It's an effective forum. Their meetings are well planned,
the agenda set, action items assigned, and followed up on at
subsequent meetings.
This has gone a long way to bring the integration
necessary to bring all these complex pieces into play.
That concludes our presentation. We welcome your
questions or comments.
DR. WYMER: Thank you very much. I like your list
of challenges. Those are about the ones I guess we would
have come up with here since we've had discussions on this
in some degree of detail or other.
Let me ask you about a couple of specific things:
One is the status of rubblization. I know that Maine Yankee
has come in, and I know that they have sort of backed off a
little bit from it now because of the State of Maine's
requirements that are more stringent than the NRC's, I
think.
And where does that stand now? Do you have a
sense?
MR. NELSON: I can tell you where the Maine Yankee
review stands. Maine Yankee has submitted and LTP and they
have asked us to review the LTP that has been submitted to
us, which includes rubblization.
They have told us that they plan to submit a
revision to their License Termination Plan. We don't know
the extent of that revision; we don't know what they're
going to change. And until -- whether or not they remove
the rubblization concept is a question I can't answer.
That plan is tentatively scheduled -- the revised
plan, they have committed to try to submit a revised plan by
the 31st of October, and until we get the revision, we won't
know what's in it.
But in the meantime, we are proceeding with the
review of the plan they have submitted, and that review is
ongoing, and at such time that we get a revision, we'll
review the revision and make adjustments as necessary.
So rubblization is still in the -- still part of
that concept and we are reviewing it.
DR. WYMER: The second question has to do with
clearance. We know that Secretary Richardson has put a hold
on everything with respect to releasing materials,
especially like the nickel from the K-25 plant, which causes
a lot of problems to everybody.
But that then -- the DOE then, as I understand it,
turned it over to the NRC and said, okay, give us a ruling.
And NRC turned to the National Academy of Sciences and said,
write us a report.
What's the status of the report?
MR. NELSON: I'm not personally involved with the
clearance rule or the release of solid material rulemaking
efforts. I'm looking around to see if there is anyone from
the staff who might be able to address that.
MS. TROTTIER: Where's my microphone? I'm
Michelle Trottier, Research. We are expecting a proposal
from the Academy by week's end. I think that's tomorrow.
Their Governing Board has met. They have reviewed
what their staff put together based on what we submitted to
them in our Statement of Work, and so we expect to be
beginning that shortly. But it has not commenced yet.
DR. WYMER: It will take a couple of years before
you get the report?
MS. TROTTIER: It probably will. I do think that
what the Governing Board was concerned with was the
timeframe. The Commission wanted a very short turnaround on
this, and I suspect that what we will see from the Academy
will ask for a little more time.
But nonetheless, it is not a simple issue, as you
might guess.
DR. WYMER: Okay, thanks. Let me ask, John, have
you got any specific questions?
CHAIRMAN GARRICK: Well, I am trying to figure out
what the real technical issues are here, so that we can be
helpful. Larry had mentioned that one of the primary
problems was the identification of viable third parties to
oversee sights, et cetera, et cetera.
I agree with Ray that this last viewgraph is
pretty much on target with what we have identified as some
of the issues.
But when you talk to a lot of the facilities
people and the reactor people, in particular, and ask them
what are the primary problems associated with
decommissioning, more often than not what comes out of that
is an identification of the handling of low-level waste
materials, solid materials, as being the one that has the
greatest amount of uncertainty surrounding it, or at least
if you follow the regulations as they now are, the options
seem to be quite limited.
So, the release of solid materials or the handling
of low-level waste materials product from the
decommissioning of facilities apparently continues to be a
major factor, particularly if you think about economics.
The safety issues do not seem to be particularly
significant. So, I would ask you the same question, and
that is, what do you really see as the principal problems
with our primary interest being on the technical side,
associated with an effective regulatory program on
decommissioning?
Are they pretty much what you've touched on here?
MR. NELSON: Well, I think they are. The
challenges slide, I think, are the principal challenges that
face us.
In some respects, we're on a learning curve. We
have, in addition to the dose-based rule, we have MARSSIM,
which is a new approach to site surveys, so we are in some
cases learning as we go there.
MARSSIM -- we are -- for example, the staff is
used to in a decommissioning plan, getting a very detailed
final status survey plan as part of the decommissioning
plan. Under our old guidance, NUREG CR 5849, that was
possible.
Under MARSSIM, however, you need to know -- you
need to have some information about the post-remediation
condition of your site to determine the number of samples
you need to take.
So in some respects, you can't submit the same
detail, final status survey plan to the staff up front
before you decommission.
So, that's something we're trying to gain some
comfort with, and therefore, what do we expect in the form
of a final status survey plan under MARSSIM?
That's an area where, for example, we're learning.
I wouldn't call it a significant challenge, but it is a
learning curve.
And as the industry is learning MARSSIM as they
implement it, I think that implementing MARSSIM is a new
approach, and, therefore, I think, a minor challenge.
But it's an implementation challenge, and I
wouldn't call it a real technical challenge.
Outside of those that I had identified, I think
that those are the real challenges that face us.
The dose-modeling, that would encompass things
like rubblization, because, you know, you have a different
source term with rubblization. And so you need to look at
--develop a site-specific dose model of leaving that
material behind.
MR. CAMPER: I would add to that by answering that
there are four things that I see on the horizon that the
Committee could be of assistance to the Staff on in the near
term:
The first is, you will be provided in the October
timeframe, the Staff's proposed Decommissioning Criteria for
West Valley. That will come to you as the Staff is
providing the proposed final decommissioning criteria to the
Commission about the November timeframe.
We've briefed the Commission's staff recently on
West Valley. We owe them another status report in
September, and one of the things that they specifically made
it clear to the staff on, was that they were strongly
interested in seeing ACNW input on the decommissioning
criteria.
Now, we have a very tight schedule, and we're
going to react as best we can, given that schedule, between
October and November when the Commission expects to see the
paper.
And I know that that timing is not necessarily
consistent with your normal process, but we're going to be
having some interactions with you on that. So that's a big
one on the horizon, as I see it, near-term.
Secondly, as Bob pointed out, we have put a lot of
work into going back and looking at RESRAD and D&D. We work
closely with Research in doing that.
We try to make those modeling approaches more
probabilistic in nature, to remove some of the conservatism
of the default parameters in those. I think that at some
point, having the Committee take a look at those modeling
codes in current terms, post those adjustments, and seeing
if you think that we have done all that we can do to make
them as probabilistic as possible, and to make sure that we
have the appropriate level of conservatism in the default
values, I think that's something that would be of value to
us down the pike.
Thirdly, on this issue of clearance, Stu and I
just came back from this meeting with NEI, and I will tell
you that this clearance issue is very, very big on the minds
of the reactor community that is undergoing decommissioning
or wanting to clear materials from their sites, whether they
are operational or in decommissioning.
They see it as a very large question mark. They
think it has the potential to impact the costs that they
project for decommissioning.
A number of them are coming into us with
innovative approaches. For example, Big Rock Point met with
us recently and discussed a pending licensing action in
which they want to be able to clear some materials that
would end up in landfills that would be a disposal. They
want to do that not under a 20.202, because they have
concerns about the material that would ultimately go to
landfills still being characterized as being radioactive in
nature, so they're pursuing a licensing action, and that's
sort of an interesting twist.
I think that at some point, as we look at some of
those types of licensing actions in the months to come, I
think coming to the Committee and sharing with you the
technical basis for which we are making those decisions, and
getting your input on it, and opportunity to put your
footprint on whether or not the technical logic seems to
make sense or not, would be of value to the Staff.
The finally, of course, there is the one I
mentioned earlier, that being institution controls. We'll
talk with you about that in October. I think it will be
interesting for you to hear a bit more about the role, the
possible role of DOE and what we might do further in terms
of other pathways or approaches for dealing with the
institutional controls issue.
So those are the four that I see in the near-term
where I think specific feedback from you would be of value.
CHAIRMAN GARRICK: Thank you, that's good.
DR. WYMER: George?
DR. HORNBERGER: I was particularly interested in
your reviews of the License Termination files, these 37,000
files. And so if I do the simple math here, it looks as if
you have got about 1 in 1,000 where you released a site that
maybe you shouldn't have. So, you know, a Type 1 error rate
of about 10 to the minus 3, and NRC probably wants to do
better than that.
And I was just curious, have you gone back, or do
you plan to look at those 38 to see what lessons are to be
learned in how you do your job? In other words, what went
wrong?
MR. BUCKLEY: The 38 cases that were identified
that were found contaminated, I think what happened was that
there was a lack of documentation in the file. In many
cases in those, there was no final survey that was done.
Those tended to be the very old licenses, the ones that were
terminated early on in the late '50s and '60s.
Oak Ridge found that the licenses that were
terminated from '85 to present turned out to be very good.
There were very few mistakes made. I believe that number is
one or two, as opposed to the remaining licenses that were
-- the sites that were contaminated. So, most of the
mistakes that were made were made early on, and from, I
would say roughly '80 forward, the results were quite good.
DR. HORNBERGER: The other thing that occurred to
me is that it might be interesting to apply D and D to at
least the 38, just to see whether or not DandD would have
kept them in. I am just -- it is just an interesting
perhaps exercise to apply DandD to a test case, or a series
of test cases where you have some interesting historical
information. And they are probably not terribly complicated
sites, although I don't know too much about these SDMP
sites. Just a thought.
DR. WYMER: Milt?
MR. LEVENSON: I have got a couple of questions.
In the area of both rubblization and clearance or free
release of material, do you perceive the technical part,
that is, monitoring what is there as being a significant
part of the problem you have?
MR. NELSON: No, I don't see that as a problem. I
think that the -- we haven't seen a problem to date in
monitoring, and I don't know why it would arise in the
future.
MR. LEVENSON: The basis of my question is that
the committee visited some decommissioning sites in Europe
in May and they did a couple of interesting things. They
don't call it rubblization, but they have solved the
hypothetical question about how do we know there isn't some
activity inside that concrete that might come out, by just
running it all through regular aggregate crushers to a
relative small size and run it under counting equipment on
conveyers and make real sure there is nothing inside before
they dispose of it.
And they have a similar sort of philosophy with
metal things. It has to have only external surfaces that
are monitorable so that things like structural steel if
there is riveted sections, they cut that out. Say maybe we
don't know what is inside between the two plates. So they
feel much more comfortable and have more public confidence
on releasing things when they can say every bit of surface
is external and has been surveyed.
I wondered if, when you get into the areas of
release, whether anybody had thought ahead about how do you
assure yourself that the monitoring really does tell you it
is okay?
MR. NELSON: Well, I will answer that in two
parts. Right now our release criteria are surface
contamination oriented. We don't have volumetric release
criteria. That volumetric release criteria question is the
crux of the release of solid material technical issue. What
are the criteria? And then what -- how do you measure that?
And that is clearly a technical issue that hasn't been
answered.
To date, if a licensee wants to release
volumetrically contaminated material, we would have to
analyze that on a case-by-case basis and do some type of
dose assessment on it. But I don't know that we have an
issue at this point with measuring it. It is, once you know
what it is, what criteria to apply, and how do you make that
assessment?
DR. WYMER: It is my understanding that the
Division of Research has issued a contract or subcontract to
study the problem of measuring volumetric contamination. I
wonder what the status of that study is. Is there anybody
in the audience who can speak to that? Here we go.
MS. TROTTIER: Actually, we have two contracts,
and these are follow-ons to work that we did for the License
Termination Rule. One is with EML, the Environmental
Measurements Laboratory, and the other one is with ORISE.
And I will make an offer to you, because Commissioner Diaz
has expressed a lot of concern about this issue,
particularly the concept of detectability, and that, you
know, he makes a true statement -- with enough effort, you
can detect anything.
So what we are doing next month is briefing him on
these contracts. And it might be worthwhile for the
committee to hear the work that we are doing, maybe at an
upcoming meeting, so that, you know, we can give you the
status. I mean these are about a year into their work and,
in fact, they are going to present their current status at
Research's Water Reactor Safety Meeting in October.
So, any time that there is time on your calendar,
and if it is of interest, we would be glad to bring our
contractors in and just give you a brief synopsis of the
progress that they are making to date on this issue. It is
basically volumetric measurements. You know, what is
capable, what is realistic? Costs, all the factors
associated with doing this kind of measurement.
DR. WYMER: Well, this is important enough, there
is enough money at stake that it probably would be worth our
while, if we can fit into our schedule, to hear something
about it.
MS. TROTTIER: Right. I understand that.
DR. WYMER: So we will talk about that.
MS. TROTTIER: Okay.
DR. WYMER: Thanks.
MS. TROTTIER: Oh, Cheryl Trottier from Research.
DR. WYMER: Let me ask around the table if the
staff has any questions? I guess we have time to invite
audience --
CHAIRMAN GARRICK: Well, I want to comment on one
thing or ask a question, because there has always got to be
one off-the-wall question, and I will provide that. I am
kind of curious as to whether or not this whole business of
contaminated sites is being looked at by some systems -- or
from a systems oriented perspective. And I am not thinking
just of radioactive contamination. I am much more worried
about the arsenic contamination in Silicon Valley, for
example, and what goes in those kind of industries than I
am, at least from a public health and safety standpoint,
than I am from these, a large number of these sites.
It just seems to me that the opportunity here is
fantastic for some creative systems engineering of looking
at these sites in the context of what makes sense to make
use of so-called restricted sites. And I guess my question
is, and I know that the NRC, I have been told many times the
NRC regulates, it doesn't solve problems, so it is probably
outside your scope, and that is why I put it in the category
of off the wall, but I wonder if there is an attempt on some
sort of an interagency basis or interagency/industry basis
to take a look at the kind of activities that are necessary
to have as a fundamental part of a society's infrastructure?
Many of them involve hazardous materials and what-have-you.
I can't believe that there wouldn't be a way to
optimize this process in such a way that every acre of these
sites could be put to very good use even if they are left in
a restricted state, if we had at our disposal the ability to
manage all activities and all hazardous operations and
manufacturing facilities, and process plants and
what-have-you.
Is there anything like this being done at a high
level that gives people assurance that these are not lands
that are lost to mankind forever? Because the truth is
there are many operations that are far more hazardous than
what we are talking about at most of these sites. And it
just seems that some creative geographer or somebody could
find very extremely effective ways to have these sites serve
mankind and take and in the end save the need for siting
some of these facilities in what are currently pristine
environments. Are you participating in anything like this?
MR. NELSON: Yes.
CHAIRMAN GARRICK: Are you aware of any such
investigations or studies?
I just think we are very uncreative as a nation
when it comes to this kind of an issue, and that radiophobia
has created such a barrier to the use of locations that have
had radiation related activities that we have become stupid
about effective utilization of our resources. And I am
curious if the NRC has ever contacted in any -- to be
engaged in any of these kinds of studies.
MR. NELSON: I am not aware of any interagency
studies that may be going on. My suspicion is if anyone
were doing it, it would be EPA. So I am not aware of any.
DR. WYMER: Let me ask if there is -- oh, a staff
member.
MR. LEVENSON: Use the microphone and identify
yourself, please.
MR. FREDRICHS: I am Tom Fredrichs, I am in NMSS
in the Division of Waste Management. And as far as reusing
some of these sites, I don't know if the NRC is involved in
any interagency sort of things, but we are cooperating with
some of the licensees to reuse these sites, some of the
reactor sites where they are going to repower with a fossil
fuel facility. And that is part of the partial site release
challenge that we have, to be able to get these sites put
back into productive use more quickly than if we would have
to wait for the entire site to be -- the license termination
process to go through.
So, I mean it is not a nationwide effort, but we
are at least making some small steps in that direction.
CHAIRMAN GARRICK: Thank you.
MR. LEVENSON: And sort of in that connection, the
question I was going to ask, and it is still relevant, is,
what are the restrictions on restricted release? What does
that really mean? What options are there for use of the
land?
MR. NELSON: I think that to a large degree
depends on a couple of things. One, the nature, amount and
physical arrangement of the material that may be left
behind, and the licensee's own intent for that land. If
there is a large amount of material buried onsite, but the
site boundary includes some buffer zone, I would imagine
that part of that site could be put to some other productive
use, maybe a park or whatever.
So, I don't think there are any restrictions on
restricted use. Restricted use doesn't mean build a three
foot concrete wall around the facility and have an armed
guard standing by. It means that you have placed -- that
there are restrictions on how you can use the site and those
restrictions would have to be based on some of the factors I
mentioned.
But, ultimately, it comes down to what the
licensee wants to use that property for. Normally, it would
remain -- the title would remain with the licensee, or the
ex-licensee once the license is terminated, and so they
would have to make the proposal on how that land would be
used or not used after the license was terminated, and the
legal mechanisms they would put in place to ensure that that
was the only uses that the land would be put to use for.
MR. LEVENSON: Yes, I think that the sites
probably, John, generally fall into two categories, those
that were power plants. That means they have access to
cooling water and media that makes them good for power
plants, and they are probably people who will seriously
consider reusing the site. I think the more difficult one
are the nonpower plant sites.
CHAIRMAN GARRICK: Yes.
MR. LEVENSON: Which might not have motivation the
same way as for power plants. Power plant sites are at such
a premium that somebody is going to repower them.
MR. NELSON: Well, let me say we know of no power
plant that is planning on a restricted release at this
point. The only restricted release proposals that have been
submitted or discussed with us have been from materials
licensees. So, I don't think -- at this point the reuse of
power plants is not an issue.
MR. CAMPER: Yes. I would only add to that, I was
going to comment sooner or later, if you look at the power
plant sites, I mean they really are pristine in the final
analysis. I mean typically there is not a groundwater
problem. And even though License Termination Plans have
been submitted designed to meet our standard of 25 millirem
and ALARA unrestricted, when it is all said and done, as a
result of the scabbling and decontamination takes place, if
you look at your final site survey results, you are probably
going to find those sites in the order of a few millirem.
So, they really are quite clean.
It is the more complicated process sites or
material sites that pose problems, not the least of which,
of course, is groundwater in some cases.
DR. WYMER: Yes. DOE has a whole bunch of
materials handling sites, as you know, and they also face
the problem of restricted release and greenfield release,
and some of the solutions, just for Milt's -- answering
Milt's question, some of the things that they are
recommending range from wildlife management parks to parks
for children to manufacturing sites. There is almost an
infinite spectrum of things, pretty much as you have
indicated. It depends on the imagination and the wishes of
the people that are on site.
MR. NELSON: Right. And we have seen some variety
in those material sites. For example, Jefferson Proving
Ground site in Madison, Indiana, they fully plan to use that
as a game reserve, and to have a portion of the site
available under the Fish and Wildlife Service, another
portion to the Air National Guard, but the DU contaminated
portion would be restricted access and would be retained as
a game reserve under the Fish and Wildlife Service, that is
their proposal.
In a number of other cases, probably the greatest
majority of those 12 sites are looking at some from of
onsite disposal of large volumes of waste and some type of
an impoundment cell.
So, there is a variety of approaches and, again,
the nature of the restrictions will have to depend on those,
you know, the three or four criteria identified earlier.
DR. WYMER: Okay. I would like to give the
members of the audience a chance to participate, and I think
maybe in order to start, I would like to see if there is
anybody from the Nuclear Energy Institute who would like to
comment on this, who is in the audience, since I am sure
they have been involved in all of these areas one way or
another.
I guess not. Is there anybody else in the
audience that wants to make any comments? It is a passive
group.
[Laughter.]
MR. NELSON: We just gave an excellent
presentation and answered all their questions.
DR. WYMER: We appreciate it. Thank you very
much. I think we picked up 20 minutes to work on letter
writing.
MR. NELSON: Thank you for your time.
CHAIRMAN GARRICK: Thank you.
[Pause.]
CHAIRMAN GARRICK: I think what we would like to
do, and we don't need to be on the record for this, is
review the one remaining letter that we have.
[Recess.]
CHAIRMAN GARRICK: We'll come back to order.
The next item on our agenda is hydrology research.
The committee member that is going to lead this discussion
will be George Hornberger.
DR. HORNBERGER: Great. I am not prepared to
lead.
[Laughter.]
DR. HORNBERGER: Okay, so actually you will recall
that we have had a number of discussions related to research
being conducted by the Office of Research and this is a
continuation on it. In one sense we are lucky in that we
overlapped with a workshop that Tom Nicholson put together,
but it was held simultaneously. We are unlucky that we
couldn't attend it, but we are lucky that we have some of
the people who are in town because of the workshop, not
because of the ACNW meeting, willing to stay over and come
to the ACNW meeting, although Lynn might say that they came
to the ACNW meeting and Tom was lucky that they were here
for his workshop.
[Laughter.]
CHAIRMAN GARRICK: Are you suggesting they
wouldn't come to the ACNW meeting?
DR. HORNBERGER: We have presentations from
several people, and Phil, you are going to go first?
MR. OTT: First, with a little introduction.
DR. HORNBERGER: Oh, okay. Bill is going to do
the introduction. Sorry, go ahead.
MR. OTT: Bill Ott from the Office of Research.
My first remark is there is no luck involved at
all. When Tom was planning the symposium I essentially told
him let's try and do it in conjunction with an ACNW meeting
so that we can have some overlap and meet with you.
CHAIRMAN GARRICK: You have made us feel better
already.
[Laughter.]
MR. OTT: We are actually attempting to come to
you more often and help you at the end of the year be
prepared to write something on the Research program. A
couple of months ago we had Linda come in. We've got Shlomo
and Glendon and Phil and Peter here today. We hope to do
this at least once more, maybe twice more this year and
bring in some other contractors to meet with you.
Today we have got the PIs that are essentially
running the hydrogeology research in the program. We have
projects with both Pacific Northwest National Laboratory and
the University of Arizona. We are basically looking at
uncertainties related to modeling of hydrogeologic systems.
Specifically, we are looking at parameter
uncertainty, primarily at PNNL, and in conceptual model
uncertainty. They represent two aspects of the program.
The work at PNNL is directly responsive to a user
need. It is the work that was requested of us by NMSS. It
is currently being used by NMSS and is being used by the
Office of Research in terms of helping to improve models
like RESRAD and DandD.
The work at the University of Arizona is not user
need originated. It is essentially what we call
anticipatory research and was initiated because we conceived
of a potential problem in the future dealing with
assertions, allegations, whatever by opponents of licensing
actions, that we just have the wrong conceptual model, how
do we deal with the uncertainties associated with such
contentions.
That's really about all I wanted to say. I wanted
to point out the difference and indicate that we are trying
to do this to help you guys with your Research report.
Oh -- one other thing I wanted to mention. There
are other activities going on in the conceptual model area.
The National Academy should come out with a report this fall
on the symposium that was held about a year ago out in
California. This fall at the AGU meeting in San Francisco
there is going to be a special session, which I believe was
organized by Shlomo on uncertainties in modeling and he may
mention more about that during his talk.
Without further ado, I will introduce Phil Meyer,
who is one of the PIs on the PNNL project. Phil?
MR. MEYER: Thank you, Bill.
My name is Philip Meyer. I would like to just
make sure that everybody realizes that my colleague, Glendon
Gee, is here as well and will be available for question
answering. Because the research symposium was held, we also
have a lot of additional material. Should that come up in
questions we'll be pleased to provide that.
I am going to be talking in pretty broad, overview
terms here in a short presentation and we will have more
later, if needed.
Like Bill said, the motivation for this research
is that it was undertaken in response to a user need from
NMSS and in the broadest of terms our work is intended to
support the development of guidance for the termination,
license termination process.
The general background for the problem is that the
dose assessments that are used in the determination of the
safety of the site rely on simplified models in a lot of
cases. The models are formulated in addition with fairly
limited site-specific data and these are characteristics of
the analyses that the Staff with NMSS are very concerned
about and that were uppermost in our minds in addressing the
issues.
Given that these two conditions hold, the result
is that when you make predictions of dose for comparison
with the regulatory standard that those predictions are
uncertain, and our research is intended to provide the NRC
Staff with improved tools to address that uncertainty and to
quantify it.
I'd just point out that this consideration of
uncertainty is consistent with the risk-informed approach
adopted by the NRC.
The research objectives of our project were to
document a method for assessing uncertainty and in doing
this we have extended previous methods that we have
developed for the NRC in previous project work on the Low
Level Waste Program and also for SDMP sites.
The emphasis here is to try to provide practical
tools, so will work fairly closely with NMSS Staff to
provide them with tools that they can use and tools that
they need as they proceed through their guidance
development.
In addition, they specifically asked us, the NRC
specifically asked us to look at three codes -- DandD,
RESRAD, and MEPAS. These are three dose assessment codes
that you may or may not be familiar with that are used by
their licensees and by the NRC Staff.
That is not to say that any of the methods that we
have worked with are not applicable to other codes but we
are specifically directed to look at these codes.
The relationship of this project to other
projects -- there's work that was mentioned this morning
regarding modifications and improvements to the DandD code
and the RESRAD code. Those projects are going on at Sandia
and Argonne National Laboratories and information that we
developed on generic probability and distributions for soil
hydraulic parameters has been incorporated in those two
codes recently in terms of the default parameter
distributions that have been implemented in the latest
versions of those two codes.
In addition, we are collaborating with Drs. Neuman
and Wierenga on some of the work that they are currently
doing that they done in the past. The monitoring project at
the Maricopa site in Arizona gathered a fair amount of data
which we are trying to use in our test case applications
that we're currently working on and the current project on
conceptual model uncertainty has a lot in common with our
work, and we have been trying to interact with Dr. Neuman on
that.
Just some brief background so that I can be as
complete as possible. You might ask yourself why hydrologic
uncertainty is even important, and the reasons are fairly
straightforward. One is that when you calculate dose you
find that the dose is very dependent upon the hydrology, so
the calculation of dose is sensitive to your conceptual and
parameterization of the hydrologic components of the
problem.
In particular, with the relatively simplified
models that we are looking at, there's two basic terms, the
source term -- which is a function of the amount of water
that enters the waste -- we refer to that as net
infiltration, being the water that passes below the zone of
the roots, where it would be possibly taken back up through
evapotranspiration.
The other thing is that the travel times with
these models, and not only these models but in reality, the
travel times of the contaminants are dependent upon the
net -- the net infiltration as well.
So the dose is very sensitive to the hydrologic
terms and in addition the hydrologic terms are difficult to
estimate accurately, particularly given limited data at many
of these sites, and in addition to limited data the
properties, hydrologic properties, often vary spatially and
temporally, so it makes them -- with limited data you have
possibly greater uncertainty about what the parameter values
should be.
I have already mentioned that the codes are using
fairly simplified models for relatively complex processes.
Just a couple examples of the kind of variability
that we're talking about. This is some data from the Las
Cruces trench site on saturated hydraulic conductivity.
It is well-known that saturated hydraulic
conductivity varies spatially significantly and you can see
here that the variability on this plot, which was a number
of meters in dimension, is several orders of magnitude.
On the right-hand side here is the data from the
USDA facility in Coshocton, Ohio that shows the drainage
from four lysimeters located at the same location
essentially and you can see that there's a lot of
variability. This is annual drainage from lysimeters. You
can see there's a lot of variability between lysimeters and
also a lot of variability over time.
In terms of having a short record, if you have a
record of data at a site it is going to tend to be short.
You have to try to represent the long-term average process
at a site. Using a short record you are liable to be
inaccurate in that estimate.
Just an additional example to illustrate spacial
variability -- this is a site on the Hanford site where
Glendon is currently conducting some experiments, and there
has been some experimental work in the past. This is just
an interpolation from bore holes, bore hole geophysical logs
of the bulk density at this site, and you can see a lot of
variability and you can also see that although at this site
you might interpret the bulk density as resulting in a
layered process, in fact it is not perfectly layered and the
experiments conducted at the site have illustrated that a
lot of the water -- waterflow and transport -- at the site
from a point source injection does not travel downward but
in fact moves laterally.
And that's important because a site like this, if
you wanted to model it with a code like RESRAD, MEPAS, or
D&D. You would have to assume that the flow and transport
was one-dimensional.
In fact, here is a schematic from the RESRAD
documentation, illustrating some of the approximations used
in that code. And I list some of the important
approximations over here.
As I said, you have to assume that all flow is
one-dimensional, and, in fact, that it's steady state, and
also occurs under a unit gradient.
In addition, the code only allows simple layering,
and within each layer, the properties have to be homogeneous
and isotropic.
And in addition, the transport curves, absorption
process curves is modeled linearly and in an equilibrium
state.
And in addition to those, with any code, you have
numerical approximations to the equations that you're
solving, and in this code they may be, because of the
simplifications, may be more severe than others.
DR. HORNBERGER: What does isoptropy mean in one
dimension?
MR. MEYER: Well, of course, there is no isoptropy
in one dimension. I'm just pointing out that you don't have
an option. If you have a site where you have clearly
anisotropic properties, you can't represent that.
So, the basic procedure for assessing uncertainty
is to first off, assess the code's conceptual model and
identify the hydrologic parameters, which is not too hard to
do with the simplified codes, since the parameter set is
fairly limited.
One of the issues is, due to the simplification,
the codes use lumped parameters, as I have already
discussed, and that has implications for an uncertainty
assessment because in that case, you're looking for, in
terms of the parameter uncertainty, you're looking for the
uncertainty in that lumped parameter. You're looking for
the uncertainty in a parameter that has to represent a
fairly large area of -- a fairly large domain.
And that both helps you and it hurts you. I helps
you in the fact that you can use -- that there are sources
of information for the parameter probability distributions
that are probably more valuable because you're looking at a
lumped parameter, but at the same time, that parameter
really represents and effective parameter at the site, and
so you have difficulty in interpreting measurements that
might be made at the site in terms of what the proper
effective parameter for the scale of the model should be.
We have worked to identify sources of information
for parameter probability distributions, and I mentioned
those previously, that some of that information has been
incorporated into RESRAD and D&D, and we have also looked at
ways to combine generic information that might represent
value of a parameter obtained from data gathered across the
country and applied to a particular site.
We call that generic information, in that it's not
site-specific; it represents an average value for, say, a
particular soil type for measurements made across the
country or within a larger region, and contrasts that to
site-specific data which is gathered actually on the site.
In terms of an uncertainty assessment, you need
some way to combine those two types of information, and we
have provided a plausible method to do that.
In terms of the actual analysis itself, Monte
Carlo simulation is used. The codes, RESRAD, and MEPAS both
have built in Monte Carlo shells that are available to use
with those codes to get probabilistic results, and D&D,
they're currently working on that option.
One other thing: We look at sensitivity analysis
and statistical correlation measures to try evaluate
parameters that are critical to the analysis. Those
parameters would be useful to probably gather more
information on them, that sort of issue.
So, as far as the status of the project, one of
the tools that we have provided to the NRC staff is a
simplified water budget model that gives you a transient
estimate of the components of a water balance in the near
surface.
The code uses or tries to use available climatic
data and a very simple flow representation in order to be
applicable at the majority of sites with the limited data
that we anticipate to be available.
It has been delivered to the NRC staff, and we've
got a water resources research paper that is currently in
press.
This NUREG 6656 provides a variety of information
that goes into more detail. I believe the Committee all got
a copy of that.
It goes into more detail on what I've talked about
and the methods that we're currently using.
I was out here in February of this year, and
provided an all-day training session to NRC staff, and we
are currently applying the methods to hypothetical test
cases. These are intended to demonstrate the application of
a lot of things. They are a lot easier to understand, once
you see an actual demonstration.
And this test case, we actually got a lot of the
information from the NRC staff in terms of the source, the
characteristics of the source, and the scenarios that we're
looking at, trying to make it as applicable to their license
review process as possible, their termination review
process.
And there is a variety of analyses that we're
looking at. That report on the test case application should
be out by September.
Some of the remaining work that we've identified
are problems that have come up in terms of -- as we go along
with the analysis -- are proper definition of effective
parameter values. I've actually had in my presentations, a
number of licensees come up and talk to me about their
particular sites, and this is always one of their issues, is
that they've got a scattering of data and they're trying to
apply one of these models.
And they don't know how to reconcile, and what the
best way to reconcile the data is, with the respective model
that they're trying to use.
There are a couple of issues involved there, only
one of which is effective parameter values. The other one
is something that Slomo is going to talk about in a minute,
and that's whether or not they should be or how to decide
whether or not their site fits within the framework of the
codes that I have been talking about.
Another issue is the general applicability of
Bayesian Methods which are used to combine the site-specific
information with more generic information on soil property
distributions.
CHAIRMAN GARRICK: Are they already in your
methods, the Bayesian Methods?
MR. MEYER: Yes. Well, there is one particular
method that is documented in one of the NUREGS that we put
out that we have been working with.
CHAIRMAN GARRICK: But that bullet doesn't mean
that you're questioning their applicability? No?
MR. MEYER: I'm not questioning the applicability.
CHAIRMAN GARRICK: Okay.
MR. MEYER: Establishing the general
applicability, under what conditions should they be used and
when should you --
CHAIRMAN GARRICK: The answer to that is obvious;
they are generally applicable.
[Laughter.]
MR. NELSON: The question is how to apply them.
CHAIRMAN GARRICK: Yes, that's right.
MR. MEYER: We had a little bit of discussion
about this yesterday, the pitfalls or the issues to look out
for. One of the other issues that has come up is the
interpretation of uncertainty assessment results when you're
using simplified and/or conservative codes.
That's an issue that I have just started to talk
about or just started to think about. I haven't talked
about it too much yet. But it seems to me that there's a
little bit more to the issue of when you're using a
conservative code when you apply an uncertainty assessment,
what exactly the uncertainty assessment results mean.
It's clear to me what they mean when you're trying
to represent a site as realistically as possible, but if
you're working on a conservative analysis, it's not always
clear cut, and I think it deserves a little bit more
investigation.
Another issue is the relationship between
conceptual model uncertainty and parameter uncertainty for
these simplified codes, and hopefully that's something that
Slomo will be able to help me out on.
There is a variety of statistical correlation
measures that have been proposed for use, and I haven't
really seen any good guidance on how to use those,
particularly with respect to this particular problem.
In any event, this project is scheduled to be
completed next year in October, and so we will have whatever
work done at that point. That's all I've prepared.
DR. HORNBERGER: Thanks, Bill. Questions? Milt?
MR. LEVENSON: Yes, have one. In assessing the
uncertainty for simplified models or conservative models, et
cetera, do you find the uncertainty distribution as
significantly different?
That is, I would guess that in a simplified model,
the uncertainty might be symmetrical, whereas in a
conservative model, it's highly unlikely that the
uncertainty is symmetrical, and, therefore, you're getting
into evaluating uncertainty and you need to connect that
somewhat with the basic way you got the number in the first
place; is that right?
MR. MEYER: I'm not exactly clear on what you're
asking, but in general, the uncertainty tends to be -- the
uncertainty in dose tends to be highly skewed, in my
observations, so that you -- the distribution of dose has --
tends to have a few values that are significantly larger and
you've got a few cases in terms of your Monte Carlo results
that result in very high doses, significantly higher,
perhaps, then the median dose.
MR. LEVENSON: Yes, that comes out of the Monte
Carlo, but the question is, if you've used kind of a
simplified model, do you see a different skewing than if
you're basically starting with something that's a very
conservative model.
In a very conservative model, wouldn't you find
fewer high doses in the uncertainty range?
We tend to use uncertainty as though it was
symmetrical and independent of the number to which you apply
it, and I don't think that's really correct.
DR. HORNBERGER: Perhaps I'll try to help clarify
that.
MR. MEYER: Okay.
DR. HORNBERGER: The idea might be, if you have
your log K distribution and you use the realistic log K
distribution, even in a simplified model, then more or less
you're taking into account that you could be wrong on both
sides.
If, on the other hand, you took a, quote/unquote,
conservative case and said, well, I'm going to not use that
hydraulic conductivity distribution; I'm only going to use
the very high end, then you would be injecting some
asymmetry into the uncertainty involved because it would be
much more unlikely that you would have higher values than
you chose.
MR. MEYER: Yes, and that's my point out worrying
about the interpretation of the results of an uncertainty
analysis when you're using conservative models.
That's my concern, is that how do you -- it's not
clear to me how you actually interpret the result, if you
have a conservative model? The parameters really mean
something different than instead of really meaning the way
that I tend to interpret a parameter uncertainty. It's that
it represents a degree of belief in the actual value of that
parameter.
So if you're trying to represent some extreme
values or more unlikely values, at the same time, trying to
interpret the results as this is my degree of belief of the
way the dose is going to be, those two seem to be
irreconcilable to me.
MR. LEVENSON: I think I would agree, and that's
why I raised the question. There is a tendency to make
certain assumptions that uncertainty really defines that
things could be worse.
And if you're doing conservative calculations, it
may be that all the of uncertainty is on the other side.
MR. MEYER: Right.
MR. LEVENSON: I'd encourage you to pursue that
effort.
DR. HORNBERGER: Ray, do you have anything?
DR. WYMER: No.
DR. HORNBERGER: John?
CHAIRMAN GARRICK: In your applications, have you
begun to develop any feel -- or in your trial applications
-- for how the contributors to uncertainty are distributed?
For example, how much does the retardation
phenomenon contribute to the uncertainty? That's an
interesting question, and, of course, it's very
isotope-dependent.
But that's why I qualify it by saying in your
applications, what have you learned about the principal
sources of uncertainty?
MR. MEYER: In terms of these simplified codes,
because they are simplified, the processes, the choice of
processes as to what's going to actually have the most
influence on dose, and, therefore, probably contribute to
most uncertainties, is fairly limited.
And I mentioned the net infiltration rate having a
strong influence on the dose. The distribution coefficient
also is extremely important for exactly the same reasons.
One is that it largely controls the release in these models.
The controls are released from the source, so it
determines how much stays up in the source, in which case it
could be good or bad, depending upon whether you have a
pathway available to the surface that's independent of the
release from the source in water.
And the other thing that the distribution
coefficient controls is the rate of transport via water.
CHAIRMAN GARRICK: Right.
MR. MEYER: So those are really the two dominating
factors in terms of the parameters that I have looked at.
There are also some parameters that are particular
to some of these models. In RESRAD you have to decide how
you're going to -- or what the parameters are that govern
the well location and the pumping rate from the well, and
those are sort of related to the exposure. It's something
that's difficult to predict how someone in the future, how
the well -- some hypothetical well in the future is going to
be configured.
And those parameters are pretty important also,
that's my experience. Some of the other parameters that you
might expect would be pretty important like the saturated
hydraulic conductivity, because of the simplifications in
the models themselves, tends to be less important, but maybe
not realistic.
DR. HORNBERGER: Phil, as you know, if I look at
D&D, in particular, that code, as you know, it was really
developed as a screening tool. Now, whether you believe
that's good, bad, or indifferent, that really was the intent
when it was developed at Sandia.
And I'm just curious. In your work, obviously now
your work and others' work on D&D is moving toward using
this screening code in a more realistic context.
Do you see any problems in doing that?
MR. MEYER: I definitely do. And part of it's the
issue of applying a screening code in not so much in --
well, I mean, there is an issue of applying it in a
site-specific case, but I think that that's more of a
standard hydrogeological problem, deciding whether any code
is applicable at a particular site.
There is nothing unique about that. I think the
D&D code is fairly limited. It was intended to be limited,
have limited application that should be conservative.
So, that's separate from the issue of trying to
apply D&D using a probabilistic analysis, and that's the
issue that we've been talking about, and I have some strong
reservations at this point about that. That's sort of my
intuitive feeling, but I haven't done any technical analysis
to try to clarify that or make it clear to other people.
DR. HORNBERGER: Okay. The other question that I
have is, clearly, as you said in not just D&D but RESRAD and
MEPAS as well, you have to wind up, if you're going to use
these in a site-specific case, defining effective parameter
value, because they are effective parameters that are lumped
models throughout.
So, you've done some work on how you might define
these effective parameters. What I'm curious about is that
in some of these sites, the evaluation is to be over fairly
protracted periods, long time periods.
And my guess is that some of these effective
parameters might depend upon the climate forcing that you
have. And if your time periods are long enough and your
climate changes, have you investigated how effective
parameters might not be constant parameters?
MR. MEYER: Not really. I mean, one of the issues
-- well, no, I'd say I haven't really looked into that.
I think that, just thinking about it, other than
the forcing term from the top, the amount of water that
you're applying to the system, I can't think of anything
that would change. I mean, the soil properties are going to
evolve over time, over a thousand years, and I don't know
how much they would change, but probably relatively little.
So I haven't really looked into whether or not the
effective value of the properties of the soil or a KD term
would depend upon the amount of water you're applying to the
system. I don't know if --
DR. HORNBERGER: What about rooting depth?
MR. MEYER: Rooting depth only comes in -- let's
see, in RESRAD, rooting depth only comes in in terms of the
external pathway -- not the external pathway, but the plant
uptake.
So, you know, those are issues that are -- it's
really hard to deal with those.
DR. HORNBERGER: Those are unknowns.
MR. MEYER: Because you're speculating about
future conditions.
MR. OTT: Thanks, Bill. We have asked the
investigators to be reasonably brief so that they will be
available afterwards for a group discussion so you can quiz
them again.
So, both Phil and Glendon will be here after Slomo
and Pete get done. But with that, I'd like to introduce Dr.
Slomo Neuman from the University of Arizona, and Dr. Pete
Wierenga.
Slomo will give the general overview for the
project. The project also involves some test cases and
using some datasets, one of which is actively being
developed at the Apache Leap tuft site, and Dr. Wierenga
will speak to that during the presentation.
MR. NEUMAN: Good morning. I do appreciate the
opportunity to talk about our research with the ACNW with
respect to the last two days' workshop. I can tell you that
I have gotten away from it with one full page of handwritten
suggestions, ideas and comments that I find very useful for
my future work.
One very important element of the work we are
doing is peer review, so any review and any comments that we
can get from people with various backgrounds as this group
would be, we would welcome.
The project that we are working on is formally
titled Testing of Groundwater Flow and Transport Models. I
am collaborating with our outgoing Department Head of Soil,
Water and Environmental Science, Professor Peter Wierenga.
The work has both theoretical, computational, and laboratory
as well as primarily field components, so what we will do is
I will present a very short overview, hopefully short
overview, of what we are doing and then ask Peter to tell
you a little bit about one of the major field studies that
we are presently conducting in support of this work.
The object of our study as defined by the NRC are
models of groundwater flow and transport as they impact
performance assessment not only -- I understand that today
you are focusing on decommissioning -- decommissioning
reviews would be one aspect where these kinds of models
would have some importance, but we are asked to actually
consider the broader context of decommissioning, uranium
recovery, low level and high level waste, so really it is
the gamut of groundwater flow and transport modeling or
modeling aspects as they impact virtually anything that the
NRC is doing where groundwater plays a role.
The motivation for this study was that a number of
years ago NRC Staff has identified conceptual models of site
hydrogeology as a major source of uncertainty in performance
assessment in any of these contexts.
I will not have time to define conceptual models,
but let me just say that I understand behind the term
"conceptual model" any hydrogeologic interpretation of site
data. You go to a site. You collect whatever geological,
hydrologic and other information you can, and you face a
problem in that the subsurface is very complex. You have
very limited information even when the database is large
about that subsurface.
The system is an open environmental system and it
is in the nature of open environmental systems of this kind
that they are given to multiple interpretations. In the
language of modeling they are given to the promulgation of
multiple conceptual models, so the objective as defined for
us was to recognize this and to develop as well as test to
the extent possible experimentally -- this is why we are
running an experimental component -- a method or a strategy
for, first of all, selecting the correct model or range of
models, interpretations for the available data, evaluating
them, and hopefully coming up with some idea of how to
assess the uncertainty associated with multiple
interpretations.
Now I consider the NRC to have been prescient in
its recognition of both of these problems, conceptualization
and associated uncertainty, because very shortly after their
request for proposal has come out, others have formally
started recognizing that conceptual modeling is indeed of
major importance for environmental issues
In particular, I thought that I would mention to a
recent National Academy book called, "Research Needs in
Subsurface Science," which was focused on the EM Science
Program within DOE, and it lists four research emphases.
The second in the list is conceptual modeling.
They propose to in fact do basic research in this
area. They think that such basic research may eventually
bring about the development of a tool box or methodologies
and the NRC in fact is hoping that we will come up with a
toolbox which focuses on new ideas, very strongly on
groundwater heterogeneity because the subsurface is so
complex and variable, scale dependence, and various aspects
of uncertainty, so we are conducting our field work as well
as much of our theoretical primarily in areas that encompass
this range of issues.
One of the very first things that we were formally
asked to do as part of this project is to review the
literature, and that included a good number of
representative NRC environmental impact and other types of
reports, but more so the general hydrogeologic literature
and this is how I would today, from today's perspective,
characterize some of the main conclusions that I have drawn
from this literature survey.
I would start by saying that virtually all, with
very few exceptions, attempts at groundwater modeling, not
only by regulatory agencies or the DOE but virtually by
every practitioner today, as well as very often by academics
is to adopt a single conceptual model and once you decide
what interpretation of the existing data you are willing to
accept, you then run with it.
When we say that we are dealing with conceptual
models, I think it would be fair to say that we are dealing
with the most important and fundamental aspect of modeling,
the very first step, where you decide what is it that you
are going to deal with and how are you going to deal with
it, the conceptual framework?
I will refer to it later in the conceptual
mathematical context as the structural framework, the nature
of your equations, not so much the parameters that enter
into them, but just how do you write your equations, what
processes do you include, what area are you going to study,
what inputs are you going to adopt as being significant to
your problem.
What perhaps surprised me to some extent, and
perhaps less so, was that I found myself focusing at the
beginning primarily on what a statistician might call Type
II modeling errors, and that is the adoption of an invalid
hypothesis, in the language of the statistician -- for us it
would be a model by not rejecting a model that perhaps is
not entirely supported by the available data.
You may have a draft methodology report in your
hand which contains not all but some of the many examples
that I have collected, and many of them in the regulatory
context -- not all of them in the regulatory context --
where this arises.
And so I have literally focused on that very, very
heavily until now. What is wrong with some of the models
that people have been using? Why is it wrong, and what can
be done? How can this be remedied?
I really think that everyone, including the NRC,
needs help in just recognizing this problem. So I would say
that Type II models are the most pernicious type, and for a
scientist, they are always the worst, because no scientist
wants to be caught with a criticism saying your theory is
wrong.
Less so are Type I modeling errors, which also are
a result of selecting a single conceptual model. Those
types of errors arise due to the fact that even though the
model you have selected may be justified by the data that
you have used to come up with it, there may be, and very
often there are, alternative models which are equally
likely, which you have not considered.
So you have, by rejection, essentially -- by
omission, rejected possible valued alternatives which may or
may not be important to the final performance assessment
questions that you're asking, but that has to be
established.
Type I errors are important to or can be analyzed
using existing statistical methods, much more easily than
Type II methods. So, our approach at the present is to look
primarily in a subjective manner at this type of error and
try to introduce quantitatively uncertainty due to the other
type of error.
It becomes very apparent, primarily because of
Type I errors, that by working with a single hydrogeologic
concept, a priori, and never considering anything else, one
would, a priori, underestimate uncertainty, because of
under-sampling of the model space, but even of more concern,
at least of concern to me, is the possible statistical bias,
if you wish, introduced by Type II errors when one chooses
an invalid model.
So, I was very concerned with that for quite some
time and still am.
CHAIRMAN GARRICK: Do you distinguish between the
issue of invalid model and the misuse of a valid model?
Under sampling could be a misuse of a valid model.
MR. NEUMAN: Not necessarily a misuse, but by
selecting a model which is appropriate for the task, given
the data that is available, all models that we use are
conditioned on the information available to us. The
information is never complete, so everything is conditioned
on what you have.
By not considering other possibilities, you may be
excluding outcomes of a performance assessment that you
should not be excluding, so the outcomes that you do
consider may be valid outcomes, given the information that
you have.
But there may be other valid outcomes which simply
never enter into the picture.
CHAIRMAN GARRICK: That's what you mean by the
alternative?
MR. NEUMAN: Then we mean exactly the same. And
in the report, there are quite a number of examples, one of
them, for example, being the issue of what causes the high
hydraulic gradient on the Northwest side of Yucca Mountain.
And I present in the report in your hands, a
step-by-step analysis that I have done of -- I don't
remember how many -- seven, eight, nine, quite different
conceptual models that have been proposed by various people
for this. And I rank them according to my own
understanding.
And it is this kind of ranking that I hope we will
be able to incorporate into eventually a guidance document,
which is what the NRC hopes. I don't know how successful
such a guidance document can be. It can never encompass all
possibilities, but that should be an example of what we hope
to do in terms of Type II errors, in particular, in other
words, eliminate all models that are not fully supported by
all the available data, and rank the remaining ones in terms
of this the most likely or most plausible in light of the
data and so on and so on.
So, this is systematic conceptualization, as well
as an attempt to introduce uncertainty into the analysis,
due to less than ideal models. A question which is of great
importance to those who use simplified models -- of course,
the NRC, as well as other regulatory agencies, as well as
the DOE, do rely on multimedia models in which the
hydrogeologic component -- and I cannot speak to other
components -- is greatly oversimplified.
So the question then arises, and, in fact, has
been raised earlier, how does that simplification impact
both the choice of the model and the uncertainty associated
with it, the Type I and Type II errors?
One of the things we will try to do is to come up
with a formalism by which a complex hydrogeologic
environment, as it is implied by the available data, could
be simplified by appropriate averaging techniques, whether
it is averaging in space, or averaging in time. Our
preference is averaging in probability space, because it
maintains some of the information about spacial variability
that is so important to geologists and hydrogeologists.
But it certainly is not the only way in which this
can be done. But one of the conclusions from my literature
survey was -- and I was surprised to hear this gentleman ask
earlier about conservative complex models versus less
conservative simple models, because what I keep hearing from
the NRC licensing staff, and what I keep reading in the NRC
documents, and not only NRC, is the notion that simple
models are, a priori, conservative, simple and perhaps
generic.
And I find that not to be the case in many cases
-- in most cases I have examined.
So it's kind of a little bit going the other way.
Here is what we are then attempting to do:
We are attempting to develop a methodology which
addresses the issues I have just listed. It definitely does
focus on the subsurface hydrogeologic aspect of things, so
it doesn't cover everything.
The two elements are conceptualization and
uncertainty. Our work is generic in that it should apply to
the entire gamut of groundwater-related modeling activities
that the NRC is concerned with, but we hope that it will be
of practical use.
I hear today that the NMSS is not finding the
material we have so far released as being of direct
practical use to them. I am surprised to hear that in light
of my review, because I think that some of the examples I
have included should already have been of use as examples of
how one should attempt to eliminate Type II errors, which,
in fact, can be found in some documents.
But we will try, and this will require more
communication between us and the NRC over the next year or
two. We will try to make it sound even more practical by
developing step-by-step guidelines to what one should be
doing.
We are very much interested, and I think it's very
important that our research be supported by real site data.
And this is one reason why we are applying, testing some
aspects of the ideas and the methodologies that we are
developing, on real sites.
And the ultimate product should be a systematic
framework for identifying and quantifying uncertainty, once
the systematic logic for conceptualization has been
completed.
As Phil Meyer has pointed out, we benefit from
collaboration with PNNL, and here are some examples of
actual collaboration: Exchange of databases, learning
methodologies, especially the Bayesian Methodology, which
one of my students has used, the one that Phil Meyer has
developed with Glendon and his colleagues.
It was already mentioned that Mary Hill of the
USGS and I are organizing a special session for the Fall
meeting on predictive uncertainty of groundwater models. I
was hoping originally that it would be a special session,
not only on predictive uncertainty but also on conceptual
models. That was vetoed by the AGU committee that looked at
it.
They consider conceptual modeling to be a nebulous
concept, not clear just exactly what it means, and very
little work has been done. I forgot to mention, but that
was one of my findings from the literature survey.
There is virtually nothing in the hydrologic
literature. I shouldn't say nothing, but virtually nothing
about conceptual modeling.
It's starting to come out. This book that was
mentioned earlier, which is supposed to come out will soon
be perhaps one of the very first things about it.
And we hope to eventually transfer this
information through some kind of a workshop to the NRC
licensing staff. We envision, at the current budget rate,
to complete this in about two years. If the budget changes,
so will this change.
Now, I will not go at this point into the details
of this overhead, because I think I'm taking more time than
I should, but I will mention that there is an established
methodology in groundwater modeling -- I will refer to it as
the traditional approach. This is the most recent and
sophisticated representation of that traditional approach.
There is an approach that one can use with
existing tools and concepts and very often does use in
groundwater hydrology where one postulates a deterministic
model, then postulates an uncertainty model for the
parameters. Sometimes, if there are monitoring data,
optimizes these parameters, these prior parameters to come
up with posterior parameters and associated uncertainty, and
then propagates the uncertainties through the model. There
are various techniques to do that.
We hope to transcend this by incorporating in this
methodology, ideas relating to structural model uncertainty,
the conceptual mathematical aspects, and ideas which are so
important in a geology where things vary on a multiplicity
of scales beneath your feet, no matter where you go.
There are issues of resolution of information lost
by averaging. There are serious issues of scale, and
uncertainty or randomness due to an inability to measure
everything beneath our feet.
These issues to which I refer to as stochastic
elements, because they are typically treated in a stochastic
manner, these two aspects, we are working on, incorporating,
piecemeal, because there is no way we can cover the field,
into our theory -- or into our methodology, I should say.
So that would be the first bullet on this next
overhead, integration of structural and stochastic aspects
into the traditional uncertainty analysis that is presently
available as a tool, perhaps has to be put into a single
document, but we are finding that that doesn't always work.
One of the requirements at this stage is to come
up with effective parameters. I'm so happy that that
concept has arisen earlier.
These effective parameters encounter a severe
problem of scale. An effective parameter for this volume is
not generally going to be the same as an effective parameter
for this volume, and an effective parameter for one type of
hydrogeologic variable is going to be different than for
another.
So, we find that the traditional approach may
sometimes not be the best, and so we are also developing and
looking at potential non-traditional ways of incorporating
those two aspects into the methodology.
I will finish my part of the discussion by just
alerting you to this. There is a series of two overheads.
I will not go through this unless you ask me to go
specifically through some aspects.
But it lists for you, work to date, part of which
has been completed, and part of which is ongoing. And under
each element here, work element, you will see whether it is
ongoing or completed.
I did mention the literature review which resulted
in the letter report of March, 1998. A draft methodology
letter report, which we hope will evolve into a NUREG,
hopefully rather soon, that was published last November.
Our field laboratory -- we have more than one, but
the active field laboratory now is the Apache Leap research
site, and I remember talking to you about that last time we
met. Probably the members of the Committee are not entirely
the same, but nevertheless, I'll be happy to go back to that
discussion.
I will only mention, and then stop, that the past
work that was done at the Apache Leap research site, which
is an unsaturated fractured rock site, was done with
high-level nuclear waste as the focus, though the work is
entirely generic, and most of the work that my group has
been doing there -- of course there were previous groups
also under NRC support that have been doing work there --
most of our work was associated with air testing and
characterization of the rock, as well as study of scaling
properties and so on, using air.
All of that has now been completed. It has led to
a certain conceptual framework that we feel comfortable
with, and that was an evolution, and I will be happy to
discuss that, if that is of interest to you.
The question we are asking now is how relevant is
all this air testing and the results obtained from that, to
water flow? And that is of concern, not only at Yucca
Mountain. We considered this site to be a sort of analog of
Yucca Mountain, but it would be of interest to any site
close to the surface in which a fractured porous rock -- it
doesn't have to be tuft; it could be sandstone; it could be
chalk -- is encountered.
For that purpose, Professor Peter Wierenga is
running at the site, water and tracer experiments, and I
would now call on Peter to tell you a little bit about those
experiments.
DR. CAMPBELL: Before Pete gets started, I want to
apologize that we don't have his viewgraphs. We will get
copies of his viewgraphs after we're done today. And if you
accidentally in the audience got a set of viewgraphs that
are missing -- these are two-sided viewgraphs, and the ones
that were handed out, if you got a set that's only
one-sided, throw it away, and there are some two-sided
viewgraphs in the back.
MR. WIERENGA: Thank you very much. It is a
pleasure for me to present my material here at this
distinguished meeting.
The cooperators after the program, I am listing on
this overhead. This is in addition to myself and Dr.
Neuman, we have a post-Doc and a technician and a retired
scientist from the USDA, Mr. Rice, who is on an hourly basis
also helping out on this project based on his extensive,
very extensive field experience in this area.
The sites are located in southern Arizona, or
central Arizona, more or less. And we have talked today
about two sites. The site of my talk today is the Apache
Leap site. That is about the same elevation as Phoenix.
Here is Tucson and here is the border with Mexico, of
course, and there is the Maricopa site that was -- we did
earlier studies, and hopefully will continue additional
studies.
This is a regular alluvial site, and this is a
fractured rock site.
The fractured rock site was used for earlier
studies by Dr. Neuman and his students, and they did the air
permeability studies on this site, and they installed these
bore holes, vertical and standard bore holes. There is
another one somewhere here.
And they did air permeability studies between
those bore holes. They cleaned up part of the site, and
found a large fracture here, and then built our infiltration
studies over this site, so this is Plot Number 1, 2, 3, 4,
5, 6, 7, 8, 9, so we established nine plots, each three by
three meter for a total plot size of nine by nine.
And then we installed various observation points,
measuring devices, drilled holes and installed measuring
devices below the surface of these plots and then flooded
the plots with water.
We kept a constant head of water on the plot. I
show you a few slides, additional slides of that setup.
The devices that we used to measure the water
below the surface of the plots were basically three devices:
One is the neutron probe, which gives us a relative count
rate which is related to the water content or the degree of
saturation.
We used a tensiometer which measure the matric
potential in the rock material. The matric potential is
related to the energy with which the water is held in a rock
material, and then we used a solution sampler that is used
to extract the pour water from the rock material which we
then take to the laboratory to analyze.
So these three devices were installed on each plot
at different depths. This is a viewgraph of a tensiometer
which is a porous body that is filled with water and then we
have -- basically we have here a pressure transducer and the
pressure transducer has it's leads to a data logger at the
top, and the negative pressure that we measure then with the
pressure transducer after is in equilibrium and the
surrounding material is recorded, and that gives us an idea
of the degree of saturation or the matric potential of the
rock material.
This is one phase of the installation of the
material. This is the solution sampler. There are two
leads to the surface, and we apply vacuum on those, and draw
the samples through this porous body into the stainless
steel and then apply pressure and force it to the surface,
so we have those at five depths below the surface.
Here is a further version of the project. Here we
have completed the -- we have a concrete barrier around each
plot and these are the various devices in each plot, and
these are the supply tank, and each tank is connected to one
plot and by measuring the level of water, the rate of
waterfall in this tank we know how much water has
infiltrated to the surface of this plot. It's a fairly
simple setup.
DR. HORNBERGER: Did you tag the water at all,
Pete?
MR. WIERENGA: Now we have lately tagged it with a
bromide tracer. We would like to do additional work on it
but I will show you some results and show you what comes out
of it -- but we could tag the water in each individual plot.
DR. HORNBERGER: Right.
MR. WIERENGA: This is a later completed version.
We also built a structure over this -- this is our
instrument trailer -- so it prevents rain. Of course, the
surface of each plot, there's a floating cover on each plot
so we have no evaporation losses and whatever goes into the
plot we know pretty sure that all of that is infiltrating in
the plot.
DR. HORNBERGER: It looks like Biosphere 3.
[Laughter.]
MR. WIERENGA: Thank you. It's hot too. It is
warm and in the winter that is nice to work on it, and in
the summer it gets awfully warm, a little too hot.
There is a great deal of variation, variability --
not variability but spatial variability in the infiltration
rate. This is the cumulative amount of water that was added
to each of those plots of the first 200 days. We are now at
about Day 250 so we started this experiment just before
Christmas, started flooding it, and so you see in Plot 3 and
9 we have fairly high rates but at Plot 5, for example, we
have only a rate .036 and these are in between.
The rates are fairly steady but here they drop off
a little bit and these are also steady but then they
accelerate. Why that is? We don't really know that.
In a mineral soil you would see, of course,
initially you would have a very high rate going into a dry
soil, but as time goes on you would see a slowing down of
the rate and sometimes a great deal of slowing down of the
rate but in this fractured material this is not happening.
The data that we have from this is this is an
example of the relative count rate measured with a neutron
probe. The relative count rate, as I said, is related to
moisture content. As you see, as time goes on at 30
centimeters the water content is increasing and so is it at
55 but to a lesser degree. The water content was much
slower at 30 centimeters initially than at this depth,
therefore it has a lower count rate because of the drying
out of the profile before we started the experiment, but
then gradually wetted up.
This is the deeper one at 450 centimeters was
initially already quite moist, and there you see that it is
30 and 150 centimeters. It kind of reached the same
relative moisture content, so this is kind of the behavior
that we observed with the neutron probe.
It is a very slow process. I thought the
experiment would have already been over, but this is a
long-term experiment because the permeability of the
material is not fairly high.
Now in a vertical direction, you see a great deal
of variability. You barely see -- you see the water
infiltrating. You could see some, in this particular plot,
some response maybe down to these depths. These variations
are mostly due to uneven absorption of water from the rock
material itself by the dry bentonite that we packed around
the neutron probe. We have to pack everything with
bentonite to prevent preferential flow along the observation
devices down to the subsurface.
Another set of readings is from the tensiometers.
This is in Plot Number 9, an example of the tensiometer data
that we get with tensiometers. As you can see, there's a
couple interesting things. Initially at the surface it was
dry so you get a very negative matric potential, but as the
water front arrives it gets fairly wet, so it wets up and it
becomes closer to saturation.
The saturated soil of course, the matric potential
is zero, and that 1 meter is following and then the 2 meter
is following. The 3 meter is fairly steady. Initially it
was wetter because that became -- we packed the tensiometer
cups in a wet silica flour, and that finally diffused into
the surrounding rock but here it stabilized and then the
water front is arriving and it gets closer to saturation.
The 5 meter depths again was a little water
because of the construction of the tensiometers'
installation, then it's fairly flat and nothing -- the
waterfront clearly has not arrived there.
Now then, is this a good example or is this a bad
example? In the next slide I have plotted all of them, all
of the data from all of the tensiometers, and you see a
large variation in their behavior. While this one is
arriving fairly fast, Plot 8 is responding fairly fast, this
is at 50 centimeters, Plot 7 is really a laggard and it took
almost -- what is this? -- 100 days between the arrival
between one plot versus another, so it is not a fairly even
process and that is what you quite often see in the actual
world in the hydrogeological setting.
Now this is at one meter. Again this is arriving
later, but the behavior is also slower. It is slowly
wetting up, so it looks almost like it's matric flow and not
fractured flow in this sense. Otherwise in fractured flow
one would see a rapid increase at some depths, at some
tensiometer, but here we don't see this, but again quite a
difference between the arrival of the wetting front at that
depth.
This is the three meter one and again we see here
slowly wetting up here, here it was already. The moisture
content was relatively high already at the 2 meter depth,
but here we see for example the 6 meter one is increasing,
the 2 meter is fairly steady but then starts increasing, so
I am feeling that the moisture front has kind of arrived
after about 100 days at this particular depth, by and large.
These are the tensiometer data. Now of course
after about 200 days, we added a bromide tracer to all the
plots, to the water in all the plots, and so far we have
seen only appearance of the bromide in the subsoil of the
Plot Number 8 at 1 meter, and the amount of bromide was 30
parts per million, I believe, and so we see an increase in
the bromide concentration at this depth at, after day ten,
but we did not see any bromide at 50 centimeters, although
we have a device there, and we did not see bromide at any
other points except at 5 meters it is appearing now -- I
mean at half a meter in Plot 5 and last weekend, this past
weekend, my people told me it was up to 10 parts per
million, so this data shows fairly irregular behavior of the
water flow, but much more so of the tracers, and I think
this tracer is, in my opinion, clearly some indication of
fractured flow in this plot and perhaps this one also.
Maybe we will see more of it as the waterfront and
the tracer front is moving deeper in the profile, but so far
we have not seen any response to the tracer. What we'd like
to do also to learn a little bit more, have a different
tracer on each plot. The problem with that is the cost of
analysis goes up a little bit, and I don't know whether we
will be able to afford it, but that would give us even more
insight in the behavior of the tracer through the subsoil.
So if I can -- by the way, the bromide behavior is
also clear from the washing out of the salt. The salinity
of the subsoil is relatively high, so when the salinity
decreases, the bromide increases so we have two independent
measures that it is not an analysis problem. It is really
actual data.
So far we have regular variability in infiltration
rate. After flooding 200 days more or less you reach the 3
meter depth and we have not yet reached the 5 meter depth
except in one plot. It seems to break through.
Breakthrough of bromide has occurred at Plot 5 at half a
meter and at Plot 8 at one meter, but no bromide observed at
other points and the early bromide breakthrough in Plot 8
indicates fractured flow.
That is what I wanted to tell you about this
experiment. Hopefully, if we continue this, at least maybe
another half a year or a year, constant flooding, then we
will learn a little bit more about the importance of
fractured flow at this point. So far, I feel I wasn't
totally convinced that we would see fractured flow, but my
conceptualization of that plot was incorrect and I must now
see that we do have fractured flow at this site and that has
to be accounted for in the models even though maybe it is
happening only at one point, but one point over 9 x 9 is 81
square meters. If you multiply that over a larger area,
then it becomes quite often -- quite clear that this kind of
behavior is very important for environmental impacts.
Thank you for your interest.
DR. HORNBERGER: Thank you, Pete. I am sure we
have some questions for Slomo and Pete. I just would -- for
those on the committee who perhaps don't recognize it, I
should point out that we have a phenomenal concentration of
expertise on the vadose zone processes in semi-arid and arid
conditions in this room. Woe be the world if we had a
disaster in this room today.
[Laughter.]
DR. HORNBERGER: That is not their only expertise
but I know the committee has some interests in vadose zone
processes in arid regions, and I just want to remind you
that you can take advantage of the expertise in the room.
Questions for Pete or Shlomo? Ray, do you want to
go first or do you have to bug out?
DR. WYMER: I have to bug out. I know very little
about the field but I do know Shlomo and I am impressed with
the clarity and lucidity of it and the very high conceptual
level that you have tackled her and the information you have
presented. That is about the extent of what I can talk
knowledgeably about.
MR. LEVENSON: I just have one comment in response
to Shlomo's question. My question was really not as to
whether simple or complex models were more conservative. My
question was the distribution of uncertainty should not be
the same for conservative and nonconservative models.
MR. NEUMAN: If I may just make an observation in
that respect, one of the attributes of relatively simple
models with fewer compartments, larger compartments that is
often cited is the fact that the variance of the parameters
reduces as the size of the compartment or the averaging, the
level of averaging increases, and that is definitely true,
so you could say uncertainty goes down, but on an overhead
which I think you may have but I have not shown I make the
observation that at the same time the mean of the
distribution moves as you average, and so by averaging you
are moving, shifting the entire distribution -- yes,
indeed -- you are reducing the spread, but you are removing
the mean, and unless you are aware of it and factor it in,
you end up with a bias, and I am more concerned with that
bias -- in other words, the reduction of the uncertainty.
MR. LEVENSON: That is really the issue that I was
trying to address. Very good. Thank you.
DR. HORNBERGER: John?
CHAIRMAN GARRICK: Well, I am not going to talk
about the earth science component of this but one of the
things that this committee has spent a lot of time advising,
if you wish, the NRC on, is that analyses ought to be done
on the basis of getting a handle on results that are as
realistic as possible.
This debate of uncertainty analysis and
conservative uncertainty analysis makes no sense to me. If
you are talking about an uncertainty analysis the only time
it makes any sense to me is when it is uncertainty about
what you consider to be a reasonable model and a reasonable
investigation.
A set of distribution functions that are called
conservative to me don't have much meaning. A set of
distribution functions that are a direct result of your best
attempt at a realistic appraisal of a parameter or an
aggregation of parameters does make sense, and then the
concept of conservatism is something you apply in the face
of that information, but I was just curious about some of
the strategies that you are adopting here as far as these
dose calculations are concerned in terms of the uncertainty
analysis and I think it is essentially an oxymoron to talk
about uncertainty analysis and conservatism.
To be sure, the distributions ought to be your
best shot at what you believe your state of knowledge is
about a parameter --
MR. NEUMAN: I am extremely glad to hear you say
that because that is exactly my philosophy.
CHAIRMAN GARRICK: Yes.
MR. NEUMAN: I am willing to accept from
regulatory agencies sometimes the need in the face of lack
of information and lack of ability to develop a fully
realistic model to err on the side of conservatism, but I
can think of many examples where the word "conservatism" as
you suggested has no meaning and my favorite example, which
is a very simple one, when you are propagating a solute --
it could be a contaminant or otherwise -- through a column
of porous medium it will depend, the transport will
depend -- for inert tracer will depend on the velocity and
on the dispersivity of the medium.
If you change the dispersivity, you make it small,
you get a sharp front and it will take longer for the
contaminant to reach the edge. One could say that by
therefore increasing the dispersivity, one is being
conservative because one will get a sooner and earlier
breakthrough.
Well, but at the same time, you will get a lower
peak because you have increased your dispersivity and in
that sense you are not conservative.
So I couldn't agree with you more that the notion
of conservatism often doesn't make sense, and I would
perhaps add to this that I think it has been grossly misused
and is being grossly misused.
CHAIRMAN GARRICK: Well, the point is that there
is a point beyond which you obscure the truth. You obscure
the validity of the analysis and what the evidence for that
analysis can support.
MR. MEYER: I just want to make a clarifying
comment, since you seem to be addressing some of the issues
that I raised.
The issue is not so much the use of conservative
distributions for parameter values. The parameter values,
the distributions of those that we have used in all of our
analyses, are not conservative parameters.
They represent the best estimate of the knowledge
about that parameter at a particular site, and in the face
of limited data.
However, the models themselves, the implementation
of the processes, which in the codes are intended to be
conservative in some way, and so you're taking those --
CHAIRMAN GARRICK: Well, this is --
MR. MEYER: You're taking the parameters that may
not -- that aren't conservative, but you're applying them in
models that may be intending to model the whole situation in
a conservative way.
CHAIRMAN GARRICK: It was designed that way
because it's a screening tool, and so I understand that,
yes.
But what we're trying to preach here is, let's
understand, on the basis of the evidence, what can be said
about a parameter, and then if we want to apply conservative
values or criteria to that, we can do that. But let's start
with knowing what our best shot is and what the real answer
is.
MR. MEYER: Right.
DR. HORNBERGER: Slomo and Pete, you've introduced
a very vexed question, this whole issue of structural
uncertainty, if you will. And now that you've changed -- or
Pete's changed his mind about his conceptualization, okay,
at the Apache Leap site. He just told us that.
But I'm curious now, given that, does that just
mean that you change your favorite conceptual model, or does
it mean that you actually have several different conceptual
models that you would apply now?
MR. NEUMAN: Do you want to start, Peter?
[Laughter.]
MR. WIERENGA: Well, of course, one should always
be open to different conceptual models. And focusing on one
conceptual model that things will happen, like you have in
mind beforehand, that is not the right way -- not the right
way to conduct science.
So, I think that, while I discussed it with Slomo
this morning, he thinks that a continued model with the
possibility of having fractured flow in the -- with a spot
of the -- model, is probably the way to go.
And I would agree with that. It looks to me that,
you know -- and I'm not an expert in fractured rock, but it
doesn't really matter so much, where that fracture is, but
what does matter is that the water of the tracer gets there.
And so maybe it's more important, how many of
these fracture one has per surface area that contribute to
quick transport of contaminants from the surface to the
subsoil or to the groundwater, but not necessarily, you know
-- we really don't have to know precisely, the description
of the pathway; what we need to know is what is the chance,
what is the -- how many of these pathways are there per
surface area, to do the modeling?
And maybe Slomo has a better answer to it, but,
yes, I did change my position.
MR. NEUMAN: Not better, but I just want to add a
little bit. And that is that we have been working at this
site for at least a decade now. And our concepts have been
gradually shifting.
My own work until now, as I said, was associated
with air flow. Well, we are now pretty much convinced that
in order to properly characterize air flow under the
conditions of our testing in the past, one could justify
taking this fractured medium and conceptualizing it for
modeling purposes as a heterogeneous continuum in which
permeability varies, air permeability varies form point to
point, according to a random field model.
And we have come up with a particular fractile
representation of that, but that's kind of a secondary
issue. So a continuum stochastic representation, random
field representation, seems to work for as far as describing
the heterogeneity that we could observe, based on our
experiments.
Now comes Peter's experiment, and low and behold,
I do not think that the particular air permeability model
that we have developed is fully going to explain the air
flow -- the water flow.
We don't know, though, because our air tests were
down below three-meter depths, and his water has not reached
below three meters yet. So it's extremely important that we
continue this test for at least half a year to a year to see
just how deep this will get, and hopefully so it gets into
the domain where we do have air permeability data and see
what happens.
But even more important than that is what Peter
showed you about the difference in behavior between water
and tracer. It is obvious, I think, based on his
preliminary results, and likewise obvious if you compare the
air and the water results so far, that a conceptual model
and associated mathematical model that may work for one
phenomenon, may not work for another phenomenon. And that
is the really interesting thing that is happening here.
This is why I think this idea is so interesting.
It also raises some extremely interesting scaling issues.
And so as far as I'm concerned, if I may enter a
plea here, in the past we have been working for the NRC at
other sites. One of the earlier sites was in saturated
granite at a site called Oracle.
We were able to extract a lot of very useful
information from that. One of the conceptual changes that
that site has instituted, in my own mind, is that I started
that work believing that one should be able to carefully map
in three dimensions, the distribution of fractures in
granite and then use that geometric information, plus
geologic understanding of the fractures, to make predictions
about flow.
And the conceptual shift that has occurred in my
mind was that that is not a viable way to proceed. And I
now have collected a huge set of data from other sites which
supports that.
But the plea: What has happened is that as we
have completed our -- the easy part, the hydraulic testing
part, the project's original plan called for additional
tracer testing.
But we were stopped in the midst, and we were
never able to verify that what we have learned about the
site regarding hydraulics, would also apply to contaminant
or tracer transport, because the budget was cut right there
because Congress shifted its interest onto Yucca Mountain,
and so everything had to now go into the vadose zone, and we
were dealing with the saturated zone below the water table.
It took the Department of Energy and others years
to discover what we have said at the beginning, that Yucca
Mountain does have a saturated zone, and one should not
focus only at the shallow area, but the original concept was
that contaminants will never reach that deep.
So, these concepts are changing and evolving with
time. And my plea is the following:
The same thing happened to us with air
permeability testing at the Apache Leap. The original
program was to continue with gaseous tracer tests. And
Walter Illman, I don't know if he's in the room or not, who
conducted the pneumatic tests for us, was all set up with
his technician to go ahead.
But then the budget was cut for that, and so we
have never had a chance to do tracer tests. And just think,
if Peter did not have a chance to run tracer tests in
conjunction with his water tests, how less rich would we be
about our understanding?
How much more limited would we be in our ability
to see what is happening at the site? I really think that
it is absolutely essential that there be more continuity in
the funding of projects which the NRC considers, a priori,
to be meaningful; otherwise, let's not even start funding
them.
But if you fund them, fund them continuously so
that a good amount of information of this kind can be
gained. So in this particular case, I would just simply
suggest, let's make sure that Peter has the budget to run
his experiment for at least another half a year to a year.
DR. HORNBERGER: To the extent that the ACNW
controls the Office of Research Budget, we will dot hat.
[Laughter.]
MR. NEUMAN: I know you don't.
MR. WIERENGA: I would like to add, though, that I
feel that, in general, the NRC research staff has been very
supportive and very generous in the support of my research
and Dr. Neuman's research.
But there are things outside their control, also,
like it is out of your control, it is also out of their
control.
And I'm really grateful for all of the support
that I have had from the Nuclear Regulatory Commission to do
this work. I would be happy for the support.
MR. NEUMAN: All I can say to this is amen, and,
in particular, Tom Nicholson really deserves, I think,
accolades for the way he has been supporting our research
all these years.
DR. HORNBERGER: Before I leave and let you off
the hook on my question, I'll let you guys off the hook, but
I wanted to see if I could put Glendon on the same hook,
because I know that he has a lot of insights developed from
lots of work he's done at Hanford.
Do you have any insights on this whole issue of
structural model uncertainty and how we should handle it for
vadose zones?
MR. GEE: Well, I am very interested in, and
endorse Slomo's approach. I think it's not been done
before.
Certainly Hanford is just beginning to come to
grips with these kinds of problems. Charlie Kincaid, who
basically is doing a lot of the modeling for the Hanford
site was here yesterday, but unfortunately he's not here
today to perhaps provide some insights.
But basically I think he actually came for the
two-day presentations so he could listen and learn and
hopefully integrate some of the things that are being
planned, and benefit from the NRC research in this area.
I just think it's an extremely important aspect of
the modeling that has not been looked at before, and I'm
grateful that NRC is interested in it.
DR. HORNBERGER: I just have one other general
question: I don't know if any of you -- well, I'll throw it
out and see if any of you want to answer it.
One of the things that we get asked, that is, the
ACNW, in evaluating, if you will, the NRC's research program
is to what extent the NRC should be involved in doing
research, because, after all, one argument could be made
that it should be up to the applicants for licenses to do
the research.
The other argument is that NRC has to have
expertise, capabilities to do reviews. Do you have any
insights for us on how you would weigh in on such an
argument?
MR. NEUMAN: Can I try?
DR. HORNBERGER: Slomo?
MR. NEUMAN: On this question, of course, I've
been working off and on for the NRC for quite a number of
years, and this is a question that arisen almost on every
occasion where the research program was reviewed one way or
another.
I cannot speak for the need for research by the
NRC and its contractors in areas other than the areas I am
familiar with. But it seems to me that the issues that the
NRC is facing are of tremendous complexity, and, in
particular, the issues that I'm familiar with, which pertain
to hydrogeology, groundwater being a major transporting
element in the environment of radionuclides and other
contaminants, actively or potentially.
The earth is such a complex system, and we know so
little about it that I just do not believe that it is
possible for either a regulatory agency such as the NRC or,
say, an agency such as the Department of Energy that might
apply for a license for high-level waste storage or other
entities that would apply for license that entails analysis
or requires analysis of subsurface processes.
I just don't see how the NRC could possibly do
this work in good faith and with competence, without having
a good understanding on its staff, an up-to-date,
state-of-the-art understanding of as much as possible
relating to these processes, as they pertain to the task at
hand.
It so happens that other agencies, and certainly
private groups, are not going to do the kind of research
that the NRC is currently supporting. It's unique.
Even the experiment that Peter is running now is a
unique experiment. You think about it as a simple
experiment, but it is far from simple, but it's absolutely
unique.
The Department of Energy has botched similar
experiments at the Idaho basalt site, and I can assure you
that when we concluded our work at Oracle in saturated
granite, I paraphrased to the NRC, Churchill by saying never
have so few done so much in so little time for so little
money.
[Laughter.]
MR. NEUMAN: And I can say that again.
[Laughter.]
MR. NEUMAN: And so I really think that despite
the fact that perhaps the NMSS does not always see where all
of this is leading in terms of their practical needs, I
really think that it is of relevance, and I certainly would
think that it is a very good thing for the NRC to do some
research of this kind, and perhaps more than it's doing.
MR. WIERENGA: Also there is really not much
possibilities in this country to get long-term funding for
field research, and unfortunately, we don't have right now,
the structure in the government so that we could easily do
more integrated work.
I see that we also need to do long-term work, but
also more integrated work. For example, scientists from the
National Labs could participate in an experiment that we do,
and take other measures of, let's say, how water and how
this process behaves in the subsoil. I don't see that much
happening in this country, and we don't seem to have the
mechanism for it.
But certainly we need to do some longer-term work,
and the NRC is in a position to have more continuity in
their program as opposed to an NSF grant that takes three
years, and that's almost impossible to do the work for the
type of budgets they have.
You cannot do field work for that, it's
impossible.
DR. HORNBERGER: Phil?
MR. MEYER: If I could just second what Slomo and
Peter said, but I also want to offer just a little bit
different perspective.
I have attended a number of public workshops in
which there are a lot of licensees in attendance, and both
from the questions and comments that they make in the
meeting, and also from my personal interaction when they
have come up to me and told me about their sites and what
the issues are, that they are, number one, strapped for
expertise in addressing the hydrogeologic issues at their
site.
And, number two, that probably it's related; that
they are desperate for guidance, and they look to the NRC to
give them guidance on how to analyze their sites. I don't
think that it's just that they want a -- at least that's not
my impression, that they just want a cookbook so that they
can quickly get on with, you know, the processes, but that
they seem to be genuinely concerned about doing a good job.
And in my experience, the work that the Research
Office has supported has offered a lot to the licensing
staffing the time that I have been working with the NRC.
DR. HORNBERGER: Thanks. Well, I have a host of
detailed questions, but I think they will have to wait till
Slomo's AGU session.
Thanks very much. Thank you, Mr. Chairman.
CHAIRMAN GARRICK: All right, I think that what
we'll do is recess now for lunch, and then come back and
continue our ACNW report-writing session. I should announce
that we are targeting to adjourn at 3:00, and I think this
will terminate our need for keeping a record.
[Whereupon, at 12:35 p.m., the recorded portion of
the meeting was adjourned.]
Page Last Reviewed/Updated Monday, October 02, 2017
Page Last Reviewed/Updated Monday, October 02, 2017