United States Nuclear Regulatory Commission - Protecting People and the Environment

480th ACRS Meeting - March 2, 2001

                Official Transcript of Proceedings


Title:                    Advisory Committee on Reactor Safeguards
                               480th Meeting

Docket Number:  (not applicable)

Location:                 Rockville, Maryland

Date:                     Friday, March 2, 2001

Work Order No.: NRC-097                             Pages 235-325

                   NEAL R. GROSS AND CO., INC.
                 Court Reporters and Transcribers
                  1323 Rhode Island Avenue, N.W.
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                                 + + + + +
                               480TH MEETING
                                 + + + + +
                              MARCH 2, 20001 
                                 + + + + +
                            ROCKVILLE, MARYLAND
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                       The Advisory Committee met at the Nuclear
           Regulatory Commission, Two White Flint North, Room 
           T2B3, 11545 Rockville Pike, at 8:30 a.m., Dr. George
           Apostolakis, Chairman, presiding.
           MARIO V. BONACA       
                       Vice Chairman
           THOMAS S. KRESS       
           GRAHAM LEITCH         
           DANA A. POWERS        
           ROBERT J. SEALE       
           WILLIAM J. SHACK      
                       Member .           COMMITTEE MEMBERS: (cont.)
           JOHN D. SIEBER        
           ROBERT E. UHRIG       
           GRAHAM B. WALLIS      
           F. PETER FORD         
                       Invited Guest 
           ALSO PRESENT:
           KAREN COTTON
           STEVE DOCTOR
           BILL BATEMAN
           DEBBIE JENSEN
           BILLY CROWLEY
                                 I N D E X
                         AGENDA ITEM                       PAGE
           Briefing Event at V.C. Summer Nuclear Station
           Opening Remarks
                 Chairman George Apostolakis. . . . . . . . 238
           Introduction of Participants
                 William J. Shack . . . . . . . . . . . . . 238
           V.C. Summer Background, Karen Cotton . . . . . . 239
           Discussion of Technical Review and Future  . . . 247
             Activities, Gene Carpenter
           Materials Reliability Program, Larry Matthews. . 285
             Assessment Committee . . . . . . . . . . . . . 301
             Inspection Committee . . . . . . . . . . . . . 303
             Repair and Mitigation Committee. . . . . . . . 315
                                                   (10:01 a.m.)
                       CHAIRMAN APOSTOLAKIS:  The next item is a
           briefing event at V.C. Summer Nuclear Station.  Dr.
           Shack is the lead member on this.
                       MEMBER SHACK:  I'm sure of the members are
           aware that they found a crack in the weld material of
           the reactor coolant hot leg piping system at V.C.
                       The crack occurred in alloy 182 weld
           metal, which is a high nickel weld metal that they
           typically use essentially as kind of a buttering when
           you're joining a Ferritic component, in this case a
           pressure vessel nozzle, to the stainless steel piping
           and essentially it minimizes the mismatch in thermal
           expansion and reduces thermal stresses. 
                       We know in the past that PWR primary
           coolant piping systems have been very reliable and
           we've found very little evidence of cracking in those
           systems.  They've been approved for leak-before-break,
           largely because of that reliable experience, and so
           there's some interest here in the general nature of
           whether this experience can be generalized to other
           systems.  And, again we wanted to understand just how
           well, for example, inspections can be done in other
                       Joining us on the phone today, in addition
           to the staff at the front of the table is a
           contractor, Dr. Steve Doctor from Pacific Northwest
           Laboratory, who's an ultrasonic UT for Dr. Wallis,
           expert on crack detection. And I guess Gene, you're
           going to start off, Gene Carpenter. 
                       MR. CARPENTER:  Karen Cotton will be
           discussing this.
                       MEMBER SHACK:  Okay.  Ms. Cotton then, you
           can start the discussion. 
                       MS. CARPENTER:  Okay.  First, I'd like to
           say good morning. I'm Karen Cotton and I'm a
           mechanical engineer and the project manager for V.C.
           Summer.  Gene Carpenter, from the division of
           engineering will talk about the technical review and
           future activities regarding the Summer crack.
                       Larry Matthews of Southern Nuclear, he'll
           talk about the MRP.  I would like to acknowledge Billy
           Crowley sitting here, he's the team leader for the
           special inspection team and, as you heard before, we
           have Steve Doctor on the phone listening in.
                       I'm going to discuss the history of the
           event and I'll discuss it in three parts.  I'll talk
           to you about the actual event, I will talk to you
           about what the licensee did in response to the event
           and I'll also talk about NRC's actions.  Then I'll
           give a brief synopsis of what was the function of the
           special inspection team. 
                       During refueling outage 12, during a
           routine walk through, boron deposits were discovered
           near the "A" hot leg reactor nozzle.  The licensee,
           what they did was they continued with their routine
           outage activities but they began to investigate where
           the boron was coming from.  They did a PT inspection
           and they discovered a four-inch crack.  In the four-
           inch crack, they soon found that this was only a
           surface indication. 
                       They continued and they did UT and they
           did eddy current testing and they found a two-and-a-
           half inch crack, and this exited through a weep hole.
                       Summer designated a team of industry
           experts to look at the situation, and the industry
           experts they looked at the repair and they looked at
           evaluation of the repair. Their focus was to come up
           with a root cause analysis and to come up with a
           repair method. 
                       MEMBER WALLIS:  It surprises me that the
           first thing that was mentioned was boron deposits.  I
           would think there would be all sorts of other
           indications of leaks before that.  
                       MS. COTTON:  What happened was --  
                       MEMBER WALLIS:  A new activity or just
           loss of fluid. 
                       MS. COTTON:  There were no other
           indications of leaking.  This leak was very small and
           it wasn't detected through our normal leak detection.
                       MEMBER WALLIS:  Doesn't it take a lot of
           water to make much boron deposit?
                       MR. CARPENTER:  That is correct, sir. 
           This is Gene Carpenter.  Typically, you have very
           small amounts of boron in the reactor system fluid,
           and obviously there was literally hundreds of pounds
           of water that had to escape before this was detected.
                       However, as Karen said, it was a very
           tight crack and the leak rate was much below 0.1 GPO,
           so they never did trigger the tech spec required 1.0
           in any unidentified leakage. 
                       MEMBER SHACK:  What was the unidentified
           leakage sort of in the period leading up to the
                       MS. COTTON:  It was like 0.6.
                       MEMBER SHACK:  Three-tenths.
                       MR. CARPENTER:  Yes, 0.3 GPO was about the
           average over the operating cycle.  
                       MS. COTTON:  The team's primary goal was
           to ensure that the plant would safely start up.  They
           looked at all the welds, they looked at the code
           requirements, they had to address all the failure
           scenarios, even the worst possible case.  And they
           looked at all the indications and made sure that all
           these indications in the other welds were evaluated. 
                       The licensee also developed a
           communications plan and this plan ensured good
           communications, thorough communications with NRC, with
           the other members of the nuclear industry, and also
           with the community surrounding the plant.  
                       They also took a further step and they
           committed to enhance their leak detection procedures. 
           They decided that they would examine the B and C welds
           during refueling outage 13, and they also committed to
           examining all the welds during refueling outage 14.  
                       MEMBER SHACK:  When had this weld been
           last inspected, or had it even been inspected? 
                       MR. CARPENTER:  Yes, it had been last
           inspected in 1993 during their ten year ISI. 
                       MS. COTTON:  The licensee's activity
           included we chartered a special inspection team, we
           chartered and formed a communications plan.  As part
           of the communications plan we did a communications
           team, which met on a weekly basis, bi-weekly, we met
           twice a week on a weekly basis to handle all issues
           dealing with the Summer crack.  
                       We developed a web site that was specific
           to just this Summer event. We issued three information
           notices, the last one was February 28, was issued
           February 28.  We received a WCAP from Westinghouse
           regarding the integrity of the B and C welds. We did
           a safety evaluation regarding this and we completed
           and issued the safety evaluation on the 20th of
                       We also had five public meetings, the last
           public meeting was February 15 and that was a public
           exit meeting.  We chose to have a public exit because
           all the meetings were public and we got very good
           comments from the public regarding our openness and
           our willingness to involve them in this event.  
                       The licensee's root cause analysis was
           primary water stress corrosion, and this basically was
           due to the susceptible material of alloy 182, coupled
           with the repeated welds, or the repeated rewelding and
           rework done during construction of the weld. 
                       MEMBER WALLIS:  How was the grinding
           related to residual stresses?  Was it that the
           grinding was too gross and rough, or was it something
           to do with heat generation, or what was the coupling
           between grinding and residual stresses?
                       MR. CARPENTER:  When the weld was
           originally installed they had multiple weld repairs. 
           It took, I believe, something like 40 days to do the
           complete weld repair of the Alpha hot leg nozzle weld. 
           In that time they basically took out the entire weld
           and rewelded it in at least once.  
                       MEMBER WALLIS:  So grinding wasn't
           necessarily a cause of stress at all? 
                       MR. CARPENTER:  Well, they did do a lot of
           grinding out of welds, of flaws, and then rewelding.
                       MEMBER WALLIS:  But the grinding itself
           didn't cause the stresses? 
                       MR. CARPENTER:  It added to it, sir.
                       MEMBER WALLIS:  It did?
                       MS. COTTON:  Steve, do you want to talk
           about the V-shaped?  I have a slide I could put up for
           you?  Steve?  Do you want to talk about the V welds? 
           I have a slide I could put up for you as for our
           discussion about the root cause analysis? 
                       DR. DOCTOR:  I think the key point is the
           fact that when they put in this bridge path, what this
           forced them to do was basically form a double V type
           of weld. And the work that EPRI had funded had shown
           that the stresses on the inside were much higher with
           that type of a weld design as compared a single V type
           of weld design.
                       And so the fact that you've got a grinding
           was due to remove the old material, but they used this
           bridge path and it forced the design into this double
           V type of design. 
                       (Slide change)
                       MS. COTTON:  This basically sums up the
           history portion of what actually happened.  Now we'll
           talk about the special inspection team.
                       As stated in the history, a special
           inspection team was chartered.  The focus of the team
           was to ensure that the licensee's corrective actions
           were appropriate.  They looked at and reviewed the
           root cause determinations, and they looked at all
           corrective actions activities. 
                       The team's activities included, as I said
           before, corrective action review, review of the
           licensee's records, they observed the welding
           processes, NDE activities.  They also did on site
           metallurgical analyses that reviewed this, of the
           spool piece at Westinghouse hot cell labs.  So the
           team was pretty active and they were on site for
           several weeks during this whole incident. 
                       The team's findings were that the root
           cause analysis was appropriate and acceptable and that
           there were no deviations from weld requirements.  From
           code requirements.  
                       MEMBER SHACK:  Just on this inspection,
           doing the weld techniques, do you have to go through
           the piping to inspect the weld?  Or is this something
           that is really done just through the weld metal?  
                       DR. DOCTOR:  This is Steve Doctor.  When
           you perform the inspection according to the Section 11
           requirement of ASME code, you're required to inspect
           the inner third of the weld plus some adjacent
           material on both the pipe side and the nozzle side. 
           Generally, this is approximately this a half-inch.   
                       So the inspection includes both base
           material, structural weld and buttering. 
                       MEMBER SHACK:  Steve, I guess I was
           interested in whether, for example, if you were in a
           plant that had centrifugally cast piping, in order to
           inspect this weld you would have to look through the
           cast piping. 
                       DR. DOCTOR:  That's correct. As a matter
           of fact, if you look at the cold legs those are a
           nozzle weld with buttering structural weld going to a
           cast elbow.  And they perform those inspections in a
           similar vein.  The fortunate thing is that these
           inspections are conducted from the inside, so the
           amount of cast materials, the very coarse grain cast
           materials that you have to penetrate, is relatively
                       If you perform the inspection from the
           outside surface you have extremely long paths through
           the coarse grain material, which would then make the
           inspection extremely difficult.  
                       MEMBER SHACK:  Okay.  Thank you. 
                       MS. COTTON:  The purpose of my talk was
           just to provide a snapshot of the history of what
           happened with the event.  The actual event history,
           the response of the licensee, NRC's actions, and to
           give you some detail of what happened with the special
           inspection team.      
                       Both the special inspection team and the
           staff feel that this event is beyond Summer, and that
           there are further generic activities, we should look
           into this further.  And this will be discussed by Gene
           Carpenter.  Gene.
                       MR. CARPENTER:  Thank you, Karen.  First,
           I'm going to go over the technical review that the
           staff did of the B and C hot legs, and then I'll be
           discussing some of the generic activities that the
           staff is following. 
                       The staff performed an independent
           evaluation of the licensee's assessment of the B and
           C nozzle legs. Now since they had physically removed
           the A hot leg nozzle weld and replaced it, there
           really wasn't a need to evaluate the cracks in that.
                       This was done by the licensees submittal,
           which was the WCAP-15615 Rev 1, which is a proprietary
           document and the non-proprietary version 16616 Rev 0
           which is available on the web site for public
                       The WCAP provided the results of the
           Westinghouse UT and the eddy current examinations of
           the nozzle-to-pipe welds for loops A, B and C.  In
           those loops, they found in five of the six nozzles,
           that there were crack indications -- or I should say
           eddy current indications.  The C cold leg was the only
           one that did not have any indications found.  
                       These indications were evaluated based on
           the destructive examination that was done on the A hot
           leg nozzle that was removed and was destructively
           examined at the Westinghouse hot cell facilities. 
           And, based on those determinations, the licensee
           determined that Summer could be safely operated for
           approximately two further cycles before they needed to
           do any inspections or possible repairs to the existing
           indications in the B and C hot legs.  
                       MEMBER SHACK:  Is eddy current an accepted
           inspection technique for this kind of consideration? 
                       MR. CARPENTER:  No, it is not.  They went
           beyond that.  The UT could not find these eddy current
           indications, so basically we are going beyond the code
           on this.  
                       MEMBER SHACK:  Well, how are they
           estimating sizing then for these flaws?
                       MR. CARPENTER:  The eddy current can
           determine the lengths.  We're doing a 2:1 aspect
           ratio, so basically for a one-quarter inch long crack
           indication, we're assuming that a depth of one-eighth
                       MEMBER POWERS:  How did they possibly make
           a prediction that they can operate for so long of a
           period of time without fixing these things?
                       MR. CARPENTER:  The determination was made
           on the basis of the susceptible material.  It was made
           on the basis of the crack growth rate.
                       MEMBER POWERS:  What is the crack growth
           rate in a nozzle in Summer?
                       MR. CARPENTER:  The crack growth rate that
           was assumed.
                       MEMBER POWERS:  I'm not interested in
           assumptions.  I want to know how they knew what the
           correct growth rate was.  
                       MR. CARPENTER:  When they did the
           examination, the destructive examination of the A hot
           leg, they went in and basically  - if I could flip to
           that slide.
                       (Slide change)
                       MR. CARPENTER:  This is a representation
           of the Alpha hot leg and this is the crack that grew
           through wall.  The assumption -- basically
           Westinghouse went through and evaluated the crack,
           found that there were multiple initiation sites and
           they grew together.  And from that they made a
           determination using a fairly extensive formula which,
           if you'll pardon me for just one second  - 1.4 x 10
           the minus 11, K minus 9 to the 1.1  
                       MEMBER POWERS:  Show me the experimental
           data, applicable to Summer, that validates that
                       MR. CARPENTER:  I don't have that with me,
                       MEMBER POWERS:  I mean there can't
           possibly be any data that's directly applicable to
           this to validate that formula -  unless there have
           been a lot of cracks in Summer.  I mean how do you
           justify an analysis like this that says oh, we can
           operate for two more cycles based on this magic
           formula, that is based on data for some other
                       MR. CARPENTER:  I will grant you that
           there is not a lot of data, and that was one of the
           problems that the staff had.  And that is one of the
           reasons that we did not agree with a crack growth rate
           that would allow for two cycles before they did any
           further examination.
                       We looked at the crack growth rate in this
           extremely, and bear in mind that this crack growth
           rate is assumed, is bounding the limited amount of
           data that we do have.  So what the staff did was we
           took what they licensee and Westinghouse provided to
                       MEMBER POWERS:  Now, when you say you
           bounded the data you have, I mean how do you go about
           bounding this data?  Presumably the crack can't go any
           faster than the speed of sound in the metal.  I mean
           I -- accept that as a bound.  What other bound can you
           possibly come up with?
                       MR. CARPENTER:   When you take a look at
           all the data that is provided and look at the scatter
           growth, the licensee had a best fit to that data.  The
           staff disagreed with that and we increased our
           bounding crack growth rate so that it incorporated all
           the data.
                       MEMBER POWERS: How do you know that's
           enough?  If I took two more data points maybe they
           fell outside your bound.
                       MR. CARPENTER:  We don't have two more
           data points, sir.
                       MEMBER POWERS:  Yes, but if I had taken  -
           why do I know that bound? 
                       MR. CARPENTER:  I cannot sit here and
           guarantee that this is the absolute bounding crack
           growth rate.  It is much faster than what we have
           assumed in the past.  And it is the reason that we
           were only comfortable with wide   operation,
           approximately 18 months.
                       MEMBER POWERS:  I'm trying to understand
           why you were comfortable with five minutes.  
                       DR. FORD:  Gene, can I try and help you?
                       MR. CARPENTER:  Please.
                       DR. FORD:  Is that formula that you just
           gave the Peter Scott formula?
                       MR. CARPENTER:  Yes, sir.
                       DR. FORD: That's based on secondary side
           cracks in tubes, I think.  Therefore, the argument I
           think that's being made here, Dana, is that that could
           be a worse case material environment situation.  The
           follow up question to that, however, Gene, would be if
           you used presumed residual stress profile through that
           182 crack, would you have predicted what happened on
           Leg A, using that formulation?  I think that would
           answer your question, Dana, or go towards it. 
                       MR. CARPENTER:  Perhaps, yes. 
                       MEMBER SHACK:  Well probably not because
           the residual stresses that were used for the Summer
           analysis were the standard sort of piping stresses, or
           the standard circumferential weld residual stress
           distribution which probably would have arrested the
                       MR. BATEMAN:  This is Bill Bateman from
           NRR.  We're into an area here when Gene does not have
           the technical expertise.  We do have a technical
           expertise, however, the individual is not here today,
           the one who wrote the safety evaluation and was
           involved in asking all these questions.  
                       We can follow up at a later time, if need
           be, to answer the questions when we have the
           appropriate technical expertise available.  
                       VICE CHAIR BONACA:  I just have a
           clarification, and I apologize for it.  Maybe I missed
           something during the presentation.  I thought that
           there was a claim that the crack that we found in the
           A leg was due to the unique welding process used in
           the location.  
                       MR. CARPENTER:  That is the claim that the
           licensee made, yes sir.
                       VICE CHAIR BONACA:  Okay.  But now you're
           telling me that the inspection showed that the other
           nozzles also have cracks?
                       MR. CARPENTER:  Five of the six.
                       VICE CHAIR BONACA:  Okay.  So these
           nozzles, were they subjected to the same welding
           processes as the -  
                       MR. CARPENTER:  No.
                       VICE CHAIR BONACA:  No, they were not. 
                       MEMBER SHACK:  But they do apparently have
           smaller cracks.  At least you can't see them in the
                       MR. CARPENTER:  Correct.  Okay, going
           onward.  As I was saying, the staff's review basically
           disagreed with the licensee's premise that they could
           operate for two cycles, and we said that they could
           operate for one cycle before they needed to inspect
                       Again, we decided to bound the crack
           growth rate that they had provided to us, and that's
           because there is a limited amount of crack growth
                       MEMBER WALLIS:  Can you tell me how much
           does happen in this one cycle?  How much crack growth
           do you anticipate in this one cycle's okay and two are
           not.  How much crack growth is happening in the one
           cycle which makes it impossible to operate any longer?
                       MR. CARPENTER:  Assuming that there is a
           crack indication that is one quarter inch in length,
           with an aspect ratio of 1:2, with this crack growth
           rate it will not grow three quarters of a way through
           wall in one cycle of operation.
                       MEMBER WALLIS:  But how much will it grow? 
           Halfway through the wall?
                       MR. CARPENTER:  Roughly, sir.
                       MEMBER WALLIS: So it's growing a lot?
                       MR. CARPENTER:  Yes, sir. 
                       MEMBER WALLIS:  So you'd better be careful
           about up the bounding so much.
                       MEMBER POWERS:  If the plant has some
           misadventure and they shut down, something like that. 
           Does it change the crack growth rate? 
                       MR. CARPENTER:  Define "misadventure,"
                       MEMBER POWERS:  An unplanned shut down
           SCRAM.  Something, anything.  Does that change the
           crack growth? 
                       MEMBER SHACK:   It would take an enormous
           upset event, you know, to cause mechanical crack
           growth rate here so this is really a, you know, a sort
           of stress corrosion crack growth rate.  
                       MR. CARPENTER:  Albeit rather fast.
                       MEMBER SHACK:  Yes.  I mean the 182 crack
           growth rates are really as high as you find in any
           material that you know we know in stress corrosion
           cracking.  And, as Peter mentioned, there's a fair
           amount of data on alloy 600 in the cold worked state,
           there's less data on the 182.  When you combine the
           two data sets, you have a fair amount of data so that
           you have a reasonable confidence when you bound the
           whole combined set of data because 182 is something
           like cold worked alloy 600.  You can argue that
           there's an analogy there and the existing data points
           to the 182 are basically bound by the data that you
           see for the cold worked alloy 600.
                       So if you combine the whole total data set
           there's relatively little for 182 in this PWR
           environment.  I think you can have a reasonable amount
           of confidence that the crack growth rate the staff has
           used is bounding.  
                       MEMBER POWERS:  I guess I just don't know
           where you derive your confidence here.  You've got a
           stress corrosion cracking phenomenon, it depends on
           how much stress you have.  That must be unique to this
                       MEMBER SHACK:  Oh, the crack growth rate
           that you have is a function of the stress. That is you
           have a bounding curve that it depends on the stress
           intensity at that location.  So that becomes a
           variable that you have to account for in a specific
           analysis for a specific circumstance. 
                       MEMBER POWERS:  It also depends on having
           an aggressive corrosion chemistry.  That must surely
           be unique to this situation? 
                       MEMBER SHACK:  No.  That's the one good
           thing about dealing with primary water stress
           corrosion cracking is that you probably do understand
           the chemistry environment, that is the environment
           that you've studied the crack growth in is a PWR
           primary water environment which is carefully
                       MEMBER POWERS:  Would this alloy, this
           particular weld material and all of its associated
           impurities have been exactly reproduced in this test
                       MEMBER SHACK:  Of course not.
                       MEMBER POWERS:  Well, and then you've got
           to convince me that you've bounded it. 
                       MEMBER SHACK:  But that's why you have
           data on multiple heats of material and, again you
           know, when can I say I bounded the data.  You know, as
           Gene said, I don't think you can say you have an
           absolute bound but what you have is an amount of data
           on a reasonable number of heats of material under
           chemistry conditions that are representative of what
           you have here.  It doesn't exactly represent it but
           you think the population is quite representative and
           you have to make the judgment that when you bound that
           it's reasonably close to them.
                       MEMBER POWERS:  No, I think all they've
           done is  they've parted the data points and run a
           curve that goes over the top of it.  And I don't think
           they've done any of this, okay, does the chemistry
           span the range of chemistries that I'm likely to
           encounter or not.  
                       MEMBER SHACK:  Well, the other good thing
           of course is that under ASME code conditions, the
           range of the material chemistries is not all that
           broad.  It's a fairly tightly controlled situation,
           especially for stainless steels.  Again, for ferritic
           steels, impurity levels are a good deal higher. 
           Welds, one of the bad things about welds is the fact
           that impurity levels are higher but, again, without an
           extensive study I'm not sure that you could say you've
           bounded the range but you certainly have a reasonable
                       MEMBER WALLIS:  When this crack gets
           bigger you said it could grow as much as halfway
           through, does its growth rate slow down or increase as
           it gets to such a big crack?
                       MR. CARPENTER:  As the crack grows it will
           reduce, it expends the energy so it will tend to slow
           down a bit.
                       MEMBER WALLIS:  It will slow down.  And
           when will be the next inspection?  And I guess you're
           giving them permission to run for another cycle?
                       MR. CARPENTER:  For 18 months, yes sir.
                       MEMBER WALLIS:  Eighteen months.  So
           what's going to happen in-between in the 18 months? 
           No inspection?
                       MR. CARPENTER:  I should alter that just
           slightly.  We said that they could operate for up to
           18 months.  They have told us that they're going to be
           operating for a short cycle so they will be shutting
           down before next summer to inspect. 
                       MEMBER WALLIS:  And no one will be looking
           for boron stalactites till next summer? 
                       MR. CARPENTER:  They will be looking for
           evidence of leakage.   But it's very difficult to get
           into this area during operation.
                       MEMBER WALLIS:  And you're satisfied that
           there's a good way of detecting these very small
           leaks?  They weren't detected before.  
                       MR. CARPENTER:  That is correct.  And that
           is one of the things that I will be talking about in
           a moment regarding leakage.  Okay.
                       MEMBER SHACK:  But, again, these cracks
           will still be relatively short in terms of structural
           integrity of the pipe.  You know, they'll be a long
           way from any kind of large failure, the margin to a
           small leak is admittedly much, much smaller than it is
           to a large - 
                       MEMBER WALLIS:  Well it may be fine, it'll
           just be sort of embarrassing if you go in there next
           summer and find there's a huge boron stalactite
                       MR. CARPENTER:  But also bear in mind,
           sir, that virtually all of these cracks were axial in
           nature.  As Dr. Shack said, it takes a considerable
           amount before you have a concern beyond that. 
                       Some of the ongoing activities that the
           staff is engaged in at this time is that we're
           reviewing similar cracking in foreign reactors.  We
           haven't seen anything similar to what happened at
           Summer here in the U.S., but the root causes of both
           the Summer and the Ringhals cracking in Sweden is
           PWSCC.  So we are talking with the Swedes about that. 
           We're also investigating - 
                       MEMBER WALLIS:  When you talk about PWSCC,
           is it stress corrosion cracking?
                       MR. CARPENTER:  Primary water stress
           corrosion cracking.  And we're also investigating
           reports of other foreign cracking.  We haven't yet
           been able to verify that there are others that are
           identical, or at least similar to what has happened
           here at Summer, but we are looking at that. 
                       MEMBER POWERS:  When you say identical, I
           get the sense that we don't have to be very identical
           to be about the same.  At least as far as our data
           base.  So I mean how do you -- I'm trying to
           understand the links and bounds of identicality in
           this sense.  
                       MR. CARPENTER:  Well, I'm not trying to
           say that it has to be one for one matching every
           point.  We're looking at similar welds, we're looking
           at similar locations.  Trying to find something that
           we can lump together.  
                       Some of the other ongoing activities that
           the staff is engaged in at this time is, again, we're
           looking at the generic implications of the Summer
           cracking and the industry activities.
                       Mr. Matthews of the MRP will be discussing
           in a few minutes what the PWR owners groups materials
           for a liability program is presently engaged in and I
           will leave that to his capable hands.  
                       We're also looking at the implications on
           the leak-before-break analyses that have been done for
           virtually all the PWRs at this time.  We're also
           looking at ISI programs, both deterministic and risk-
           based, seeing if we need to make any alterations to
           those programs.
                       MEMBER SIEBER:  Since you're discussing
           ISI, is there any movement to augment with another
           technique the UT examination?
                       MR. CARPENTER:  Right now the UT
           examination is required by code, and if the code needs
           to be altered then  -
                       MEMBER SIEBER:  Somebody has to put in a
           code case?
                       MR. CARPENTER:  Correct.  
                       MEMBER SIEBER: On the other hand, you can
           do the UT exam and satisfy the requirements of the
           code, but you could require an additional augmented
           inspection using other techniques.  Seems to me that
           when I look at the pictures, the weld prep for the
           examination wasn't very good and it seems also that
           probes have a pretty good footprint and maybe this is
           a very difficult weld to examine just because of
           geometry, notwithstanding the fact that you're
           shooting through a pretty thick cross section of
           material of varying grain structure and composition.
                       I take it that since these kinds of cracks
           are not reliably always found by UT, that nobody is
           making a move to do something better. 
                       MR. CARPENTER:  Well, I'm not saying that
           yet, sir, and you're leading me by about three slides. 
           So I'll discuss that in just a moment if I could
           defer, okay. 
                       MEMBER SIEBER:  All right.
                       MR. CARPENTER:  Again, as we were just
           mentioning, the ability of the code required NDE to
           detect and size small ID stress corrosion cracks, this
           is one of the things that we definitely need to get a
           handle on.  And the appropriateness of the ASME code
           standards allowing flaws approximately 10 percent of
           wall thickness that, in the case of Summer, could grow
           with such an apparent high crack growth rate.  
                       And Dr. Wallis mentioned a few moments ago
           about the effectiveness of the leak detection systems.
           These are all things that we are very much following
           and trying to get a handle on.  
                       MEMBER WALLIS:  Are you thinking of
           putting in some supplementary leak detection system in
           the places where you might detect something such as
           just by the well?
                       MR. CARPENTER:  We have discussed that
           with the industry and I believe that -- will you be
           discussing that, Larry?
                       MR. MATTHEWS:  We're going to be looking
           at it.
                       MR. CARPENTER:  Yes.  So this is part of
           what we're talking about.
                       MEMBER WALLIS:  If you're going to look at
           it, are you going to have anything in place during the
           next cycle?  
                       MR. CARPENTER:  No, sir.
                       MEMBER WALLIS:  You seem that you want to
           put something in there now.  
                       MR. CARPENTER:  The lead time for
           developing supplemental inspections or supplemental
           leakage evaluation --
                       MEMBER WALLIS:  Well it seems to me there
           was, I'm trying to remember the pictures I saw, but
           the boron stalactites were pretty obvious, right.  So
           even just a camera would see them, and that's not a
           remarkable piece of technology.  
                       MEMBER SIEBER:  Well, the boron that was
           visible was not directly at the crack in the pipe, it
           was underneath the boot and, you know, and that's
           where the air flow ventilation for that section of
           piping comes from.  So it had to appear where the boot
           was not tight. 
                       MR. CARPENTER:  When you're talking about
           all this, you know, it came out through here so it is
           not readily accessible during power operations.  
                       MEMBER SIEBER:  And it might not come out
                       MR. CARPENTER:  Correct.  
                       MEMBER WALLIS:  But it's too rough an
           environment for some sort of video surveillance?  
                       MR. CARPENTER:  I don't know the answer to
           that, sir. 
                       MEMBER SIEBER:  It could be done.  
                       MR. CARPENTER:  Some of the further
           activities that the staff is working on right now is
           that we're proposing confirmatory research into the
           primary water stress corrosion cracking issue, and
           that will include some of the NDE and the ISI issues
           that we've discussed so far. 
                       MEMBER WALLIS:  What are you trying to
                       MR. CARPENTER:  Confirmatory research
           meaning is our capability of other inspection toolings
           to go in and find and size these indications.  For
           instance --
                       MEMBER WALLIS:  This is a kind of, I know
           it's a misnomer, but research is to figure out
           something new not confirm something. 
                       MEMBER SIEBER:  But they're not
           anticipating a problem.  They have the problem.  
                       MR. CARPENTER:  Determination of a
           bounding crack growth rate and just how the residual
           stresses play into that.  Development of
           susceptibility model, and because we know that the
           welds that were, for instance, the welds at Summer
           were field fabricated, you also have some that were
           shop fabricated at other PWRs.  You have different
           materials being used at different PWRs.  So the
           susceptibility model is going to have to take a look
           at multiple factors.  
                       The assessment of possible repair and
           mitigation methods that the industry may come up with
           and overall following of industry activities.  
                       MEMBER SIEBER:  Now, in all Westinghouse
           plants with stainless steel piping do they use the 182
           weld model? 
                       MR. CARPENTER:  No, and all of the
           Westinghouse plants from my understanding is that they
           have something like virtually every weld was slightly
           different.  So it's going to add considerably to the
           complexity here of all this. 
                       DR. FORD:  Gene, could I make a comment? 
           You mentioned at the beginning of this is the generic
           activities.  When you're looking at the industry
           experience, are you confining yourself to pressurized
           water reactors?  I'm thinking specifically of the vast
           amount of boiling water reactors which are into
           hydrogen water chemistry with a lot of 182 welds. 
                       MR. CARPENTER:  Yes. Yes, sir I have been. 
           At this time we are looking specifically at Ps, we may
           expand into Bs.  But this appears to be a PWSCC
           concern right at this moment.  If we need to, we will
           expand the scope beyond that.  
                       MEMBER SIEBER:  I mean he is running at
           hot leg temperatures that are a good deal higher than
           your BWR.
                       DR. FORD:  Yes I recognize that but we
           know what the activation enthalpies are for the
           cracking in these systems, so you can make some sort
           of comparison. 
                       VICE CHAIR BONACA:  I had a question
           regarding all previous inspections, including the year
           2000.  They found no indications.  Now, what kind of
           inspections were they?  They were not using eddy
           current, of course. 
                       MR. CARPENTER:  If you don't mind I'll
           defer to Steve Doctor on that one.  Steve?
                       DR. DOCTOR:   Yes, I couldn't hear the
           complete question.  Would it be possible to have you
           repeat it,  please?
                       VICE CHAIR BONACA:  Yes.  My question is
           all previous inspections of these nozzles showed no
           indications, including the 2000 inspection.  And I was
           wondering what type of inspection that was, I mean
           what kind of technique do you use?  
                       DR. DOCTOR:  They basically employ the
           same techniques that they employed back in 1993.  The
           biggest improvement on the ultrasonic side was that
           they employed an improved transducer sled that allowed
           each transducer to independently gimble to do a better
           job of tracking the surface and thereby providing
           better coupling.
                       This was a significant improvement.  It
           didn't accommodate all the conditions that in fact are
           associated with the ID conditions of these particular
           wells.  The size of the footprint of the transducer
           and the housing that the transducer goes in is quite
           large and, as a consequence, it has some difficulty
           accommodating the root, the counterboard, and there is
           a difference in the diameter between the nozzle and
           the pipe.  
                       And, as a consequence, it did create some
           problems.  I believe that obviously one of the things
           that industry is going to be looking at in the future
           on how to ensure a better ability to track the surface
           and thereby improve the quality of the UT inspections.
                       And for this particular inspection, the
           staff at Summers and Weston, you know, agreed to use
           the eddy current.  An eddy current inspection is
           primarily a surface inspection type of technique.  It
           has not generally been used for this kind of
                       However, it is very sensitive to any kind
           of surface breaking flaws and, as you saw from I think
           the result from the Alpha leg hot outlet nozzle
           dissimilar amount of weld, the eddy current was very
           effective at detecting a number of cracks that were
           verified through the destructive testing.  And it
           should be noted that there are indications in four of
           the five other dissimilar amount of welds that we have
           found with the eddy current, they have similar
           characteristics to the cracks that were in the Alpha
           leg, but at this point there are still indications. 
           They have not been, you know, verified by any other
                       There's a possibility that some of those
           in fact may not be cracked because some of the
           indications that were found in the Alpha hot leg were
           not verified through destructive testing.  So there is
           some uncertainty there and in the analysis they've
           taken the approach to assume that, in fact, all of the
           indications are assumed to be cracks, although that's
           not proven at this point.  
                       VICE CHAIR BONACA:  So the previous
           inspection used the ultrasonic testing.  And some
           forms of eddy current, if I understand it.  
                       MR. CARPENTER:  No.  
                       VICE CHAIR BONACA:  No.  No eddy current. 
           Okay so it was ultrasonic testing.  And that is the
           standard testing that is being done by the industry,
                       MR. CARPENTER:  Correct. Code required. 
                       VICE CHAIR BONACA:  Thank you. 
                       MR. CARPENTER:  Okay.  That brings us to
           where the industry is right at this time.  The PWRs
           have proposed an industry initiative to respond to the
           cracking issue that was found at Summer.  And, as we
           have discussed with the ACRS before, the staff has an
           industry initiative process that we can utilize for
           this, in which case an issue occurs, the industry and
           the staff meets on this.  The industry proposes to
           follow this as an industry initiative, and the staff
           either forgoes any generic communications or generic
           letter per se, to tell them what needs to be done in
           lieu of the industry coming in and actually telling us
           what they're going to do following this.
                       Now at this time we have met with the
           materials reliability program on this twice now.  And
           they have proposed to respond to the issue and, again,
           Mr. Matthews will be discussing this in a couple of
                       VICE CHAIR BONACA:  I just want to get
           back to it.  It seems to me that there has to be some
           past experience of V&V on the ultrasonic testing that
           is adequate or is not adequate.  We were left here
           with a statement that says that we have eddy current
           indications of cracks in the other nozzles which were
           not identified by UT.  We're not sure yet that they're
           cracks, they may be something else.  So we're trying
           to understand, in fact to validate these observations
                       And so my question, again, is do we have
           V&V of ultrasonic testing identifying these kind of
                       MR. CARPENTER:  The Alpha hot leg had both
           eddy current testing done on it and ultrasonic
           examination.  It was then cut out, the weld was cut
           out, and was destructively examined.  As Steve Doctor
           mentioned before, some of the indications that were
           found by eddy current were not found in the
           destructive examination.  Some of the indications that
           were found by destructive examination were not found
           by UT.  So we're still struggling with that, sir. 
                       VICE CHAIR BONACA:  Okay. 
                       MEMBER SHACK:  Let me ask it in a
           different way.  The inspectors that do the
           inspections, do they go through a performance
           demonstration on stress corrosion cracks? 
                       MR. CARPENTER:  The PDI program --
           Performance Demonstration Initiative -- as I
           understand it, I'm not the expert on this.  Steve, did
           you want to respond to this? 
                       DR. DOCTOR:  Yes.  Right now this is a PWR
           issue and all the people that are really trained for
           stress corrosion cracking do inspections on BWRs. 
           There is a requirement for a supplement independent --
           regarding dissimilar amount of welds.  That has not
           been implemented as of yet.  It's in the process of
           being developed with regard to the PDI program and
           it's something like I think about 18 months off until
           that will be fully implemented, and then all
           inspectors will have to go through that. 
                       And, of course, the timeliness of the V.C.
           Summer event is that now we've identified failure
           mechanism and so the type of flaws that have to be
           included in that demonstration are PWSCC.  
                       MEMBER SHACK:  Thank you. 
                       MR. CARPENTER:  Okay. Going back to where
           we are with the MRP.  Again, the staff has met with
           the industry on this at least twice now.  We've had
           multiple telephone calls with them following up,
           discussing the agenda items that have been in these
           public meetings.  We will have another public meeting
           with the MRP in three weeks time to discuss the
           assessments that they are going to be providing to the
           staff.  We have also gone down to one of the vendor
           sites, Framatone specifically, to take a look at the
           mock up that they have been making use of to look at
           the welds for four plants that we'll be inspecting
           this spring outage.  And further technical and
           management meetings are planned to discuss what is
           going on. 
                       And now we get to the slide that Dr.
           Sieber was leading me to. 
                       (Slide change)
                       MR. CARPENTER:  Some of the staff
           expectations of the generic activities.  What we are
           hoping to come out of this with.  The MRP assessment
           of the generic susceptibilities; they have promised
           this to us by the end of March and that is what we
           will be discussing in three weeks time.
                       The NDE methodologies and the toolings
           that the industry is going to be using to do their
           examinations.  The staff has told the industry that
           they should be making use of the best practices and
           capabilities to address potential weaknesses that seem
           to have come out of this examinations at Summer.
                       If potential code cases are necessary to
           address some of the things that we have discussed
           already, the staff will be looking at those in an
           expedited manner.
                       We also need to get a better handle on the
           implications for the ISI programs and also for leak-
           before-break.  And long term assessment of the alloy
           82/182 applications, we're going to be discussing with
           the industry to take a look at that.  
                       And we'll also be looking at the review of
           their repair and mitigation methods that they will be
           proposing to us.  
                       And that concludes my discussion for this
                       MEMBER WALLIS:  I'm just wondering, the
           expectations, are results expected or activities?  
                       MR. CARPENTER:  We're hoping that there
           will be activities that will lead to results, yes. 
                       MEMBER WALLIS:  Well that's the thing, I
           see a lot of activity and I just wonder about the
                       MR. CARPENTER:  We are at the very
           beginning of this, sir, and it's too early to -- 
                       MEMBER WALLIS:  That's what concerns me a
           bit, yes.  You may discuss with industry for a long
           time without achieving anything. 
                       MR. CARPENTER:  We have made our
           expectations very clear that this is something that
           needs to be expedited.  It's not going to be a five or
           ten year practice before something occurs.  That we
           need to have something sooner.  And, again, under the
           industry initiative process, if the staff determines
           that the industry is not being as proactive as we
           would like, we always have the option of going out
           with generic communications of some sort.  
                       MEMBER WALLIS:  Well at least by next
           summer you'll have some data points?
                       MR. CARPENTER:  We certainly hope so, sir.
                       MEMBER LEITCH:  The licensee seems to make
           quite a bit out of the uniqueness of this weld in its
           original instruction.  But I guess from hearing your
           presentation, it sounds as though you are not
           accepting that idea, that you feel there's something
           more generic going on here.  Is that a correct
                       MR. CARPENTER:  Well, initially, sir, we
           were in agreement that there were, as the licensee
           correctly points out, extensive repairs done on this,
           especially as opposed to the other five welds.  That
           there were mitigations there that could have caused
           this one to be of concern but not the other five
           welds.  And then there were indications found in four
           of the other five.  And also there was indications
           found at Ringhals in Sweden, which is a similar plant.
                       MEMBER LEITCH:  Indications but not
           cracks, right?
                       MR. CARPENTER:  Not through wall cracks,
           no, sir. 
                       MEMBER SHACK:  No, but Ringhals is
           confirmed to be a crack. 
                       MR. CARPENTER:  But not through wall.  
                       MEMBER:  Yes, but it is a crack.
                       VICE CHAIR BONACA:  Ringhals identified it
           through eddy current?
                       MR. CARPENTER:  They did do eddy current
           examinations there also, yes.  That leads us to be a
           little less accepting of the uniqueness suggestion.  
                       MEMBER LEITCH:   Yes, do we know if
           there's anything unique about which plant is at
           Ringhals weld?
                       MR. CARPENTER:  Well, it's a double V
           weld.  It's fairly similar to what we were discussing
           earlier.  But, again, we really need to get a better
           handle on all this information. 
                       MEMBER WALLIS:  So the Ringhals crack is
           still growing is it?  Or has it been fixed?  
                       MR. CARPENTER:  Debbie, do you remember
           what they said?  
                       MS. JENSEN:  They did some repairs. 
           Debbie Jensen from the Office of Research.  They did
           some repairs to the Ringhals crack, but we're going to
           meet with them next month and have face to face
           conversations and exchange of technical information
           with the similarities and the differences between the
           two plants in this particular issue with the pipe
                       MEMBER WALLIS:  Well did some repairs, do
           you mean they cut out this area and rewelded it or
                       MS. JENSEN:  From what I understand, yes,
           they did some grinding and they replaced with addition
           weld metal and they took out some samples to do some
                       MEMBER LEITCH:  I have a question about
           the enhanced leak detection procedures that were
           mentioned. Are we going to get some more about that
           later, or is now an appropriate time to ask that
           question?  I'd like to know specifically how these
           leak detection procedures were enhanced.  
                       MR. CARPENTER:  Well, that's one of the
           things that we have asked the industry to go and look
           into, to see what they can develop as far as enhanced
           leak detection capabilities.  Right now we're not
           ready to discuss what could be used.  
                       MEMBER LEITCH:  Ms. Cotton in her
           presentation said that one of the licensing
           commitments was to enhance their leak detection
           procedures.  Am I to understand that the plant will go
           back in service with -- that is that that enhancement
           is future, that the plant will go back in service with
           the same leak detection procedures? 
                       MR. CROWLEY:  What they plan to do is they
           plan to do noble gas sampling and analysis to provide
           additional verification of the RCS integrity.  The
           other thing they plan to do is they're going to --
                       MEMBER LEITCH:   You say they plan to do
           that, but will they be doing that when the plant gets
           back in service?
                       MR. CROWLEY:   Yes.  Yes, that'll be when
           the plant goes back in service.  The other thing, the
           calculation of RCS water inventory balance, they plan
           to do that on a more frequent basis than they've done
           in the past to try to determine if they have
           additional leakage. 
                       They're going to add a main control board
           enunciator to alarm at 0.75 GPM such that the
           operators will be alerted prior to reaching tech spec
                       MEMBER LEITCH:  75 GPM?
                       MR. CROWLEY:  .75 GPM.  And then they're
           going to, of course this is not what the plants
           operating -- the inspection they do when they come
           down next time, they're going to have an enhanced
           boric acid inspection.  They've had boric acid
           inspections every time a plant comes down, but they're
           also going to enhance that program also. 
                       MEMBER WALLIS:  What happens when you have
           this crack and there's a leak?  Do you get a jet of
           suppurated steam coming out of it or what?
                       MEMBER SHACK:  Sure.
                       MEMBER WALLIS:  And this has properties
           like momentum?
                       MR. CARPENTER:  Yes.
                       VICE CHAIR BONACA:  It'll cut like a
                       MEMBER POWERS:  You can't get away from it
           can you. 
                       MEMBER WALLIS: But it's invisible isn't
           it?  It's invisible. It's a jet of some --
                       MR. CARPENTER:  Yes. 
                       MEMBER WALLIS: But it impacts on things
           and it carries boron with it.  The boron is in the
           steam in some form, droplets or something?  
                       MR. CARPENTER:  Yes.
                       MEMBER POWERS:  Vapor.
                       MEMBER SHACK:  It's dissolved in it. 
                       MEMBER WALLIS:  Dissolved and then it
           comes out when it condenses on a cold surface
                       MR. CROWLEY:  Well the pipe is insulated,
           of course, so it has to -- whatever vapor that comes
           out has to get through the insulation.  
                       MEMBER WALLIS:  So what happens in the
           insulation?  It deposits or is the insulation sort of
           blown off, does a hole get made in the insulation?
                       VICE CHAIR BONACA:  Cut right through it. 
                       MR. CROWLEY:  Through the same, goes
           through the same. 
                       MEMBER SIEBER:  Well, most plants have
           mirror insulation and it travels all over the place.
                       MEMBER WALLIS:  So this steam gets all
           lost in the insulation somewhere?
                       MR. CARPENTER:  Yes.
                       MEMBER SIEBER:  I was under the impression
           that most PWRs had some kind of noble gas detection as
           part of their containment radiation monitoring. 
                       MEMBER WALLIS:   Well let's go on.  That
           insulation gets hot when you put steam through it and
           you get a hot patch on it when the steam comes in
           there, so if you had thermal couplers on the
           insulation they would get hotter if you had a steam
           leak.  There seem to be so many things that could be
           done using pretty robust technology to detect some
           change that would be affected by a steam leak.  
                       MR. CARPENTER:  And these are things that
           we have asked the industry to go in and investigate
           and come back and talk to us about.  
                       MEMBER WALLIS:  But if you had to do it
           next week I would think that someone could actually
           come up with something.   I just wonder why -- it
           seems to be a slow process, this asking and coming
           back with things.  The agency doesn't seem able to
           respond quickly to the idea say let's put thermal
           couplers, or whatever it is, around something so we
           know what's going on.  
                       It may take months to make a decision.  By
           then the cycle's over anyway.  Am I describing things
           right?  It just takes forever to make -- not forever,
           but it takes so long to make decisions that it's
           unlikely that any detection system will be in place
           before the end of the cycle.  
                       MR. CARPENTER:  Well, there is detection
           systems in place at Summer.  As to what needs to be
           done at other plants --
                       MEMBER WALLIS:  Well what's the new --
           there's a new detection system in Summer? 
                       MR. CARPENTER:  Yes --
                       MR. CROWLEY:  Just the improvements that
           we --
                       MEMBER WALLIS:  Just the ones that you
           mentioned.  But they are still -- gross balances for
           the plant.  They're not focused on the area of
           concern.  There's nothing installed around the welds
           or anything like that. 
                       MEMBER SHACK:  Local leak detection is
           harder than you think because, as Jack mentioned, you
           know, water and steam have a way of moving around a
                       MEMBER WALLIS:  Well it's very true in
           your house, you get a leak in the bathroom and it
           appears in the living room.  
                       VICE CHAIR BONACA:  I just wanted to ask
           you a question about, this is not the first time that
           PWR nozzle cracks have been identified, right?  It is
           not the first time.
                       MR. CARPENTER:  I believe it is, sir. 
                       MEMBER SHACK:  Ringhals is the first,. 
                       VICE CHAIR BONACA:  Is it?  I thought
           there have been some events.
                       MR. CARPENTER:  But this is the first
           through wall crack.
                       VICE CHAIR BONACA:  Oh through wall, yes
           I understand.  But cracks which were not through wall,
           I thought there had been some instances.
                       MR. CARPENTER:  Not that I'm aware of but
           I will get back to you on that.
                       VICE CHAIR BONACA: I guess I'm going after
           the issue of, you know, this seems to throw in full
           doubt the effectiveness of ultrasonic testing as an
           inspection means, and I thought that there had been
           some significant validations of the technique. 
                       MR. CARPENTER:  The ultrasonic
           examinations of dissimilar metal welds is a little bit
           more of a challenge, so that is something as Dr.
           Doctor mentioned a little bit ago, the PDI initiative
           is looking at that and they have approximately 18
           months to come up with a solution to that. 
                       MEMBER SHACK:  I mean non-destructive
           examination, you know they're sort of trained to look
           for certain things and at this point PWSCC wasn't
           really considered to be a major problem for PWR.
                       VICE CHAIR BONACA:  I understand.  In 2000
           they had no indications.  Then eddy current comes and
           says there are indications.  There are indications to
           the point where now we're putting restrictions on how
           long they can run.  It begs the question of what do
           you do about all the other PWRs for which you have
           inspections using ultrasonic testing.  And so that's
           why I'm asking those questions.  I had more confidence
           in that testing than I'm getting out with now. 
                       MR. CARPENTER:  And these are questions
           that the staff are asking ourselves, yes. 
                       If there are no further questions we'll
           turn this over to Mr. Matthews of MRP.
                       MR. MATTHEWS:  My name is Larry Matthews,
           I work for Southern Nuclear Operating Company on the
           managing inspection and testing services group.   I'm
           also chairman of the Alloy 600 issues task group of
           the materials reliability program, and I'm going to
           give you some information about where the industry is
           and where we're headed on this issue.
                       First off, a little brief history of how
           we got to where we are.  You've heard about the crack
           and what's been done at the plant at V.C. Summer.  The
           MRP Alloy 600 issues task group took the lead on this. 
           The event occurred in October of 2000, the initial
           root cause was available early December and the issues
           implementation group, or issues and integration group,
           we can't ever decide what IIG stands for but it's the
           parent of the ITG, recommended in mid-December that
           the MRP take on as activity the resolution of generic
           issues relative to the V.C. Summer event. 
                       We received executive approval from some
           utility execs here in early January to begin
           activities.  We developed an organization and we
           worked out a fairly detailed plan and budget but it's
           evolving as we go and as we learn more.  
                       The issues task group met in January 19,
           after the V.C. Summer public meeting on the 18th, to
           address the key focus areas and we organized into
           three committees: an assessment committee, inspection
           committee and a repair and mitigation committee and
           I'll be going into what the activities of those
           committees are. 
                       We met with the staff on January 25, at
           which point we outlined the approach that we were
           planning on taking with respect to this issue, and
           solicited feedback from the staff at that point in
           time as to whether they saw things additional we
           needed to be doing. 
                       The feedback was basically they felt we
           were on the right path, saying the right kind of
           words.  Of course, the proof is in the pudding -- can
           we deliver what we say.  
                       On February 1, two of the committees had
           their initial meetings, inspection committee and
           assessment committees both met in Charlotte.  They
           further refined their plans and schedules and budgets. 
           On 2/16 there was an MRP/NRC executive management
           meeting.  This is typically a meeting we've been
           having on an annual basis where MRP executives were
           meeting with the NRC management. 
                       MEMBER WALLIS:  Has anybody done any work
                       MR. MATTHEWS:  Yes.
                       MEMBER WALLIS:   No, I mean you have all
           these meetings in the management and budgets, has
           anyone done any engineering yet?
                       MR. MATTHEWS:  Yes, yes.  I'm going to get
           to that.  
                       This issue was one of the topics that was
           discussed at the meeting along with all the other MRP
           activities, and just this week we've scheduled another
           technical meeting with NRC staff and I'll go into what
           we're going to discuss in that meeting.  
                       The industry plan includes a short term
           assessment in which we want to demonstrate that the
           continued operation of alloy 82/182 welds is
           acceptable.  We're trying to get that to the staff by
           late March.  The NSSS vendors are at work right now
           performing the analyses and working on this
                       We had a goal of getting interim
           inspection guidance.
                       MEMBER POWERS:  You say here the continued
           operation with alloy 82/182 welds, that's just the
           weld not a flawed weld that you're dealing with?
                       MR. MATTHEWS:  We want to -- well, what
           we're going to show is the margins that are available
           in there to cracking and even if it does crack, the
           margins that are available to a rupture of the pipe. 
           We're going to try and prove here that it's not really
           a safety issue, it's a leak issue, it's an operational
           issue, we have to be very concerned about it, it's
           very expensive to have this kind of leak.  But we want
           proof and show that it's not a safety issue.  
                       MEMBER POWERS:  What you want to show, I
           think, is that if you have a flaw in that weld, that
           it will not propagate rapidly to create a pipe
                       MR. MATTHEWS:  Exactly.  Analyses to that
           effect were certainly part of the report that
           Westinghouse put together for V.C. Summer.  And we
           will build on those analyses for the whole industry.
                       MEMBER POWERS:  But you're not going to
           have any more data than they did.  
                       MR. MATTHEWS:  No, not at this point in
           time.  I mean there's no more data that we can get our
           hands on right now.  We've got to go create some or
           find out what else is out there.  
                       MEMBER POWERS:  Well when you think about
           data on stress corrosion cracking, you think about
           things like residual stresses, you think about
           chemistry.  Do we have now data that are taken in
           irradiated water of the type we have in --
                       MR. MATTHEWS:  I don't think we have data
           in irradiated water, but we do have data that was
           taken with several heats of alloy 182 weld metal and
           there was created, samples cut from it, several
           samples were put into a PWR environment in an
           autoclave and tested to crack --
                       MEMBER POWERS:  When you say environment
           you're speaking of the pressure temperature
           environment not the radiation environment?
                       MR. MATTHEWS:  Not the radiation but these
           things are very, very low radiation where these welds
           are. These welds are not in the belt line region,
           they're above the core.
                       MEMBER POWERS:  Well, I mean I just can't
           help but ask, you have a lot of radiolysis product,
           water radiolysis products in these and they tend to be
           fairly aggressive chemicals as far as oxidation and
           reduction reactions.  Do they not affect the chemistry
           in these?
                       MR. MATTHEWS:  I guess I don't know the
           answer to that but the tests that we've done are
           trying to stimulate the PWR primary water as best they
           can, given that we're not doing it with a reactor. 
                       MEMBER POWERS:  Well my question is is
           temperature adequate or do you have to simulate the
           ozonides and peroxides and things like that because of
           water radiolysis?
                       MR. MATTHEWS:  I guess I don't know the
           answer to that.  We do run these plants with a
           hydrogen over pressure and it tends to scavenge those
           things pretty quickly I would hope.  
                       MEMBER WALLIS:  Even short life -- and
           this is a hot leg, this stuff has been irradiated and
           everything else a very short time before it comes to
           this spot.
                       MR. MATTHEWS:  Yes. 
                       MEMBER WALLIS:  So there could be some
           very transient type products which are in there. 
                       MR. MATTHEWS:  Yes, there could and I
           guess we haven't looked at that as an industry and
           perhaps we need to.  
                       VICE CHAIR BONACA:  I don't want to
           belabor it but it seems to me that the gentleman said
           they're trying to see if in fact this eddy current
           data is credible. 
                       MR. MATTHEWS:  The eddy current data? 
                       VICE CHAIR BONACA:  Now, assuming that you
           could prove that the eddy current indications were not
           correct, that would support your claim that this is a
           unique issue to do with that particular weld in that
           particular A leg, and all this would be gone.  So why
           won't you focus immediately on the issue of the
           validity of eddy current as a means of inspecting
           these cracks?
                       MR. MATTHEWS:  Well, we have some
           information, as I understand it, from the Ringhals
           test.  They did UT and eddy current, and over there
           the eddy current was not the save all, in fact it
           missed flaws that the UT picked up.
                       VICE CHAIR BONACA:  Okay.  The combination
           of the two seems to be an effective means you mean?  
                       MR. MATTHEWS:  Perhaps.  But the eddy
           current here was --
                       VICE CHAIR BONACA:  So you can't discount
           the eddy current indication, that's what you're saying
           right now. 
                       MR. MATTHEWS:  Yes.  It's not a proven
           technology for going in and detecting and sizing
                       MEMBER SIEBER:  And it focuses more on
           surface indications. 
                       MR. MATTHEWS:  Yes, that's right.  Another
           thing the plan included was to get out some interim
           inspection guidance for the near term outage plants,
           those plants that are coming down this spring.  That
           was completed yesterday I believe.  The letter was
           signed out to the industry.  
                       The plan also includes a longer term
           assessment of all the alloy 82 and 182 welds in the
           plants, in the PWR primary systems.  We'll be looking,
           reviewing and improving inspection technology where
           it's appropriate.  And we'll also be reviewing repair
           and mitigation methods, if necessary, working to
           develop some improvements in those. 
                       MEMBER WALLIS:  Let me ask about UT. 
           Isn't this a developing technology in the medical
           field that's highly developing, a lot more
           intelligence is used for it and they can see things
           they couldn't see before and it's improving very
           rapidly.  Is this sort of a fossilized technology, or
           are improved UT methods coming out regularly? 
                       MR. MATTHEWS:  I think the industry is
           constantly looking to try and improve their technology
           for detecting --
                       MEMBER WALLIS:  Is it happening?  
                       MR. MATTHEWS:  Yes, there's phased arrayed
           technologies that are coming out and have not been
           applied at this point to these welds, but that has
           been applied in the industry for turbine blade
           examination and things like that.  There's new
           technology being looked at by the EPRI and NDE center
           right now for much smaller --
                       MEMBER WALLIS:  Is it difficult to get
           approval for new technology because of the regulatory
                       MR. MATTHEWS:  I think the code process
           would be the more difficult thing to get it through
           but, at the same time, if there's a better way to do
           things I can think we can push it through.  
                       DR. FORD:  Can I just come back to the
           very first bullet there, the short term assessment. 
           What are the criteria for that?  What are the criteria
           that your short term assessment is correct? 
                       MR. MATTHEWS:  I'm going to -- oh, I'm
           going to give a lot more detail of what we're going to
           do there. 
                       DR. FORD:  Okay.  But there will be data? 
           There will be stress corrosion data to back it up?
                       MR. MATTHEWS:  There will be what data we
           have available will all be factored in to putting
           together the short term assessment. 
                       DR. FORD:  Okay.  
                       MR. MATTHEWS:  And while we've already
           started work on much of this, we expect there is an
           approval process for the -- the senior reps we
           anticipate them approving what we're laying out in our
           plan on March 9.  But we've already started work with
           funds that were already available.  
                       Basically, these are the three committees
           under my Alloy 600 ITG and we're part of the MRP and
           the MRP is looked to the NEI as the regulatory
           interface with the NRC.  That's not to say we don't
           have technical discussions.  We do.  When there's
           technical issues to discuss with the staff, we'll
           discuss them directly. 
                       MEMBER WALLIS:  Excuse me.  Who does the
           work?  Do you contract with somebody? 
                       MR. MATTHEWS:  Most of the work would be
           contracted to vendors or consultants or done in house
           at EPRI.  Most of the technical work, a lot of the
           guidance and overseeing of all that work is done by
           these committees.  And these people are knowledgeable
           people in the industry in these areas too, on the
                       These are just the chairmen of the three
           committees that we've set up.  The chairman of the
           assessment committee is Vaughn Wagoner from CPNL.  The
           chairman of the inspection committee is Tom Alley from
           Duke.  And the chairman of the repair and mitigation
           committee is Gary Moffatt from the V.C. Summer plant.
                       One more detail about the committee
           activities.  The first thing is to get this short term
           safety assessment done, the process that we've
           outlined involves identifying areas that are likely to
           be the most susceptible and that's primarily going to
           be based in this very short term on evaluating the
           size of the welds, the temperature and the weld
           materials.  We felt that likely spots would be on the
           Westinghouse and combustion plants to hot leg pipe
           welds.  At BNW is may indeed be the CRDM nozzle welds
           at the top of the head, but they also have some other
           pipe welds that they'll be looking at I believe.
                       Certainly not all the plants have the same
           welds.  The difference between the vendor designs, the
           piping is completely different on the three plants, or
           plant designs, and even within the Westinghouse fleet,
           these welds have a wide variety of how they were
           constructed.  Some shop welds, some field welds, some
           stainless steel, some inconel 182 butter with 82 weld
           material, so there's a wide variety of those and we
           have to go out and assess all of those. 
                       One of the goals is to demonstrate that
           most of the cracks will be axial or in the case of the
           head penetrations they will be in the axial radio
           direction as was seen at the Oconee. 
                       MEMBER WALLIS:  Why will they be axial?
                       MR. MATTHEWS: It's primarily because of
           the stress field that the --
                       MEMBER WALLIS:  The stress field stresses
           it more highly in that direction?
                       MR. MATTHEWS:  Yes.  Well the stress is in
           the circumferential making the crack --
                       MEMBER WALLIS:  The flow direction has
           nothing to do with it? 
                       MR. MATTHEWS:  No.  
                       MEMBER WALLIS:  Well flows have effects
           around bends and things.  Flows have some effects on
           these things don't they?
                       MR. MATTHEWS:  A little bit of flow
           momentum I would imagine but I don't -- then that
           would be taken into account.  That's going to be
           second order compared to the other stresses that are
           driving these things.  
                       MEMBER LEITCH:  Are you going to -- can
           you go back and identify welds where there was major
           repair activity at the time of original construction. 
           Is that one of the things you're going to be looking
           at here?  It seems to me if that was not the prime
           cause of this failure, certainly I think we would all
           agree that it accelerated the failure in this
           particular A hot leg.  So can you go back and identify
           those welds?
                       MR. MATTHEWS:  The amount of data that's
           available to each plant varies depending on, you know,
           some of these plants are 20, 30 years old and their
           construction records are sometimes hard to come by. 
           But what's available is available and will be looked
           at by the individual utilities to see if there's
                       MEMBER WALLIS:  So chemistry comes into
           this propagation of the crack, chemistry is a factor.
                       MR. MATTHEWS:  Water chemistry?
                       MEMBER WALLIS:  Yes.  And so there's a
           whole lot of flow mechanics and diffusion processes
           and things going on in these cracks.  It's not just
           stresses, it's everything else, too.  I just wonder
           how well that is understood.  The biggest axial crack
           with the water whipping by with some sort of flow
           percolating around through the crack as well. 
                       MR. MATTHEWS:  These cracks are so very,
           very, very tight.  The water in those cracks is
           probably --
                       MEMBER WALLIS:  Well something has to go
           up there, there's going to be corrosion effects.
                       MR. MATTHEWS:  Yes, but it's a very
           stagnant environment. 
                       MEMBER WALLIS:  So it's diffusion.
                       DR. FORD:  If I -- maybe I could just help
           you out maybe.  In boiling water reactors where you
           have an oxidizing environment, yes, the direction of
           flow could be important.  But, in fact, the water does
           not enter into the crack very deeply and it becomes
           more an academic exercise.
                       MEMBER WALLIS: What's in the crack?
                       DR. FORD:  Well all this water but you're
           talking about a replenishment of the water, and that
           does not occur to any great extent in these tight
                       The question of the PWRs, you're not going
           to get too much flow effect, rate effects in this
           reducing environment, if you do have a reducing
           environment, and Dana's observation is an interesting
           one as far as I'm concerned.  
                       MEMBER SIEBER:  Maybe I could ask another
           question.  It seems to me that 82/182 I think and
           alloy 600 are all, as far as stress corrosion
           cracking, are all dependent on temperature.  And the
           need is what, 608, 609 degrees Fahrenheit where higher
           temperatures than that to correct growth rate
           accelerates.  It would seem to me, and I worked in a
           plant at one time, where because of the finding of
           some cracks, they reduced the temperature at the plant
           by about 10 degrees which virtually stopped the growth
           of the crack.  Has anybody considered that as an
           alternative to all these other things?  
                       MEMBER SHACK:  People do it in steam
           generators.  That's generally a pretty drastic step. 
                       MEMBER SIEBER:  Yes, well you lose some
           megawatts that way but a pipe break is a pretty
           drastic thing, too.  And given the choice, I would
           rather lose a few megawatts.  
                       MR. MATTHEWS:  I don't think anybody's
           considered at this point trying to reduce their hot
           leg temperatures because of this.  The drop may have
           to be significant to get it down below that need that
           you're talking about I would think. 
                       MEMBER SIEBER:  Well, it might have to be
           below 600.  On the other hand, for a lot of plants
           that's seven or eight or 10 degrees.  
                       MR. MATTHEWS:  And for a lot of plants
           it's more than that.  
                       MEMBER SIEBER:  Well, and so I continue to
           question.  You know, once you're above 610 as a hot
           leg temperature, that means the reactor vessel head is
           at the same temperature, well the inconel welds up
           there that are also subject to the same kind of
                       MEMBER SHACK:  But you know he has a much
           different problem than the steam generator people. 
           You know, they have typically much larger margins to
           failure.  A short crack in a steam generator gets you
           a lot closer to failure than a short crack in a large
           diameter pipe.   It certainly could be done but it
           certainly seems pretty far down on his list.
                       MR. MATTHEWS:  And the temperature effects
           are certainly going to be taken into account in our
           assessment of susceptibility and crack growth.  And
           temperature is one of the factors in the crack growth,
                       MEMBER POWERS:  When you think about
           activation energies for processes like crack growth
           rates, you typically think about things with
           uncertainties in the activation industry on the order
           of five -- is that right?
                       MEMBER SHACK:  Yes -- it is that much.
                       MEMBER POWERS:  And so these temperatures
           that like factors two or three on the crack growth
           rate, so the difference is between the biggest between
           two cycles and one cycle is kind of the input -- the
                       MEMBER SHACK:  If all you were depending
           on was the activation energy.   But it's certainly
           true that if you dropped the temperature 20C, you'd
           get a lot.  But you may not want to. 
                       MR. MATTHEWS:  Somebody asked earlier if
           the crack growth curve that was used was essentially
           the Peters-Scott model.  Well that model was I guess
           initially based on steam generators but it was
           modified for the Alloy 600 head penetrations and that
           crack growth model was used, the modified Peters-Scott
           model was used for the susceptibility modeling that
           we've done in the industry on the head penetrations
           Alloy 600. 
                       When we tested, in the test data that
           we've seen on the Alloy 82/182 shows those crack
           growths were, depending on the orientation with the
           dendrites, five to ten times faster than the Alloy 600
           crack growth rate.  
                       And then the curve that the NRC used
           bounded all of that so it was even more than that,
           faster than the basic modified Peters-Scott model. 
                       The short term assessment will demonstrate
           a large tolerance for axial flaws and the
           circumferential flaws.  The stress analyses that we've
           done indicate a preference for the axial cracking
           because of the stresses in the welds and how they're
           lined up.  The flaw, as you saw on the plot they put
           up, was limited to the axial length of the pipe weld,
           which is just a couple of inches long.  Basically,
           that's based on the V.C. Summer experience, it stopped
           when it hit the ferritic steel, it stopped when it hit
           the stainless steel, and it was only the inconel weld
           metal that actually experienced cracking.  
                       The flaw in the CRDM nozzle at Oconee 1
           also stopped when it hit the Ferritic steel.  It did
           propagate on into the Alloy 600 base metal of the
           penetration itself.  
                       And also the load limit fracture mechanics
           analysis will show that there's a large margin to pipe
                       MEMBER WALLIS:  These are intents or
                       MR. MATTHEWS:  We believe that this is
           what they're going to show.  
                       MEMBER WALLIS:  But is it what you want to
                       MR. MATTHEWS:  No, we believe it will show
           it.  I mean a lot of this analysis is done --
                       MEMBER WALLIS: So this is based on
           analysis having been done? 
                       MR. MATTHEWS:  The analysis -- a very
           similar type analysis has already been done for V.C.
           Summer and we're going to extend it to the rest of the
                       Similarly, for the circumferential flaws,
           a large margin, but since they can go 360 they're not
           limited by their axial.  We'll demonstrate in this
           case that leakage will be detected very easily from a
           partial flaw while there is still a large margin on
           the limit load.  
                       MEMBER WALLIS:  Are flaws necessarily
           axial or circumferential?
                       MR. MATTHEWS:  Well I guess they could be
           diagonal, depending on what's driving in and what the
           stress --
                       MEMBER WALLIS:  Do they tend to go in
           straight lines?
                       MR. MATTHEWS:  Well, they're jagged
           straight lines most of the ones I saw.  There was a
           circumferential flaw underneath at V.C. Summer that
           intersected the axial flaw but it was up underneath
           the ferritic part of the nozzle.  And it grew for a
           small distance and even that tended to turn in the
           axial direction because of the stresses we believe. 
                       DR. FORD:  Sorry, did you say the crack
           went into the ferritic steel?
                       MR. MATTHEWS:  No, underneath it. The
           ferritic steel is clad on the -- with inconel for part
           way and it grew to the ferritic and stopped.  
                       And then finally the short term safety
           assessment will present arguments similar to V.C.
           Summer's presentation on the January 18 meeting about
           the pipe -- that are covered by defense and death. 
           And piping failure has been analyzed in the SARs and
           there's systems in place to mitigate it.  Also, visual
           inspections for boric acid have been an effective way
           of identifying leaks well before there's been any
           structural margins affected anywhere. 
                       MEMBER WALLIS:  What is it you see when
           you see boric acid?  
                       MR. MATTHEWS:  Pardon?
                       MEMBER WALLIS: What do you see when you
           see boric acid?
                       MR. MATTHEWS:  Actually you see the
                       MEMBER WALLIS: You see solid boric?
                       MR. MATTHEWS:  Yes, solid boric.  And
           finding those boron deposits on the walk downs has
           been an effective way, at least to date, of finding
           flaws before there's any structural damage, structural
           margin is significantly affected.  
                       For the longer term, the assessment
           committee will complete our scope definition,
           identifying all the areas of concern.  One of the
           things we want to do is evaluate the generic
           applicability of the hot leg cracking, one of the
           elements, so that we'll be looking at finite element
           analysis including operational and residual stresses. 
                       We will assess the safety significance of
           the issue for all of the components, and then we will
           prioritize the locations based on safety significance
           into capabilities and the actual experiences in the
                       The assessment committee is also going to
           be charged with determining if any new inspection
           requirements are necessary and, if they are, such as
           ISI frequency, perhaps the ten year frequency we have
           on these may need to be modified.  We'll be looking at
           that.   And they'll assess the research needs.  Where
           are the holes?  They're defined where we need more
           information and then define research efforts to get
           that information.
                       One of the areas we'll be looking at
           certainly is crack growth data available worldwide. 
           We have some data, we think there's other data
           available in the world and we'll be gathering that
           data and factoring all of that into our analyses.
                       VICE CHAIR BONACA:  So when you're talking
           about determining inspection requirements, you're
           talking about refining the understanding of what
           inspection you need to do to detect?
                       MR. MATTHEWS:  I guess the way the
           assessment committee would do it would say what do you
           need to find and how frequently do you need to look
           for it.  And the inspection committee, which would be
           the next one, would be defining what we've got to do
           to find that kind of indication. 
                       VICE CHAIR:  Oh so you have -- okay.  Yes.
                       MR. MATTHEWS:  The next committee is the
           inspection committee. The first thing they wanted to
           do was get some guidance out for those plants with
           spring outages.  I believe that letter was signed
           yesterday by Jack Bailey from TVA, the VP there who is
           the chairman of the MRP.  The goal was to develop a
           consistent inspection approach.  After looking at it,
           the committee and the people that EPRI NDE center both
           felt that for these nozzles the ID UT was still
           considered the best available technique.  It's
           considered adequate certainly for the upcoming spring
           outages for a couple of reasons.
                       V.C. Summer's inconel weld was a field
           weld that was installed and had multiple repairs on it
           done in the field.  The ID contour on that weld was
           not necessarily the best. 
                       MEMBER WALLIS:  Tell me more about UT. I'm
           sorry, is this a thing where some diagnostician looks
           at some picture?  Or is it something where a computer
           analyzes a picture, or a computer analyzes certain
           facets of an image or what? 
                       MR. MATTHEWS:  At least for UT today, the
           way it's being done is it's a trained technician
           watches the instrument. These are automated
           instruments that are --
                       MEMBER WALLIS:  So it's as prone to error
           as diagnostic X-rays in hospitals, where someone looks
           at a picture and tries to see a crack. 
                       MR. MATTHEWS:  Well it's not a picture
           though, it's a trace on an oscilloscope.
                       MEMBER WALLIS:  Looks for some anomaly?
                       MR. MATTHEWS:  It's looking for any kind
           of anomaly and the data that's taken on these is a
           digital form of data, with hot leg alphas anyway if
           they're done from ID, it's an automated exam where the
           data's gathered and stored and digitized and can be
           then reviewed.
                       MEMBER WALLIS:  And can they zoom in or
           something?  I mean if he thinks there's something
           there can he get a magnification of the signal and
           things like that?
                       MR. MATTHEWS:  Well, you can go look at it
           closer but I mean all the data's there available for
           him to look in as much detail as is available.  
                       MEMBER WALLIS:  I'm just wondering if
           greater attention to detail in the inspection would
           buy you some better assessment.
                       MR. MATTHEWS:  We think absolutely and
           that's one of the things that we're working, that's
           one of the recommendations that we're putting out is
           to enhance the awareness of those inspectors to the
           kinds of anomalies that led to missed indications at
           V.C. Summer.  
                       MEMBER POWERS:  And Indian Point and a few
           other places.  I mean there's been pandemic missing of
           indications here.
                       VICE CHAIR BONACA:  I mean I'm somewhat
           disturbed by the top bullet, the UT is still
           considered the best available technique.
                       MR. MATTHEWS:  That's today.
                       VICE CHAIR BONACA:  I understand but you
           know the whole experience we saw in the presentation
           says that eddy current was an important complementary
           technique to identify indications that are seen as
           significant enough to say you should go only one
                       Now if this is true, it has implications
           for the other plants too, and it's hard to take then
           at face value the statement that ID UT is still
           considered the best available technique.  I may just
           have trouble in accepting both statements at the same
                       MEMBER POWERS:  Separated in time they're
                       MR. MATTHEWS:  The inspection committee
           and the people that -- everybody there with the
           inspection had worked with the results from V.C.
           Summer.  They were also aware of the indication, or
           the information out of Ringhals that those guys, the
           eddy current didn't even see some of those flaws that
           the UT did see. 
                       VICE CHAIR BONACA:  And that's why I used
           the word complementary.  That together seem to really
           yield some information.  
                       MR. MATTHEWS:  The problem the industry
           has with UT at this point is it's never been used
           except at Ringhals and at V.C. Summer.  We don't
           really know  what's in the VNC loop, we haven't really
           got a clue in my mind what's there.  There's
           indications there.  They haven't been proven, we don't
           know what it is.  And to jump in there with an
           unproven technique on a plant that's down for a
           regular ISI and say, okay, you find a scratch in
           there, now you're limited and you've got to come back
           and do the cold leg again next cycle.  
                       We felt it was a little premature for the
           industry to jump to something like that. 
                       VICE CHAIR BONACA:  But for your plant,
           still you have restrictions based on ET.
                       MR. MATTHEWS:  Well, it's not my plant,
           it's V.C. Summer.  No, I'm from Southern Nuclear.  
                       VICE CHAIR BONACA: Oh I thought -- I'm
           sorry, all right.  
                       MR. MATTHEWS:  The way the mergers are
           going I don't think it's my plant.  
                       VICE CHAIR BONACA:  I was referring to
           that, jut I confused the two, all right.
                       MR. MATTHEWS:  Another thing that the
           inspection committee did do is there was a mock-up
           available that the EPRI NDE center had of this type of
           weld, with imbedded flaws.  Now admitted they were
           fatigue flaws but it's the best we've got right now. 
           Some of those flaws are very shallow and we
           recommended that the plants, and there's a very
           limited number of plants with iconel welds here on the
           hot leg that are going in for inspections this spring,
           I think there's actually only three plants with
                       And we recommended that those plants have
           their vendors perform a demonstration of their
           techniques on the EPRI mock-up, and all those vendors
           have done so and, as a result of doing those
           demonstrations, there have actually been some
           modifications to the procedures that were being used. 
           New transducers and new scanning gains on the
           instruments to get a more sensitive examination.  
                       Also, we said that we were going to
           enhance the awareness of inspectors and not just be
           willing to say, well, I got 90 percent coverage on
           that weld, that meets the code.  If you get a lift off
           do what you can to remedy that situation.  And be
           aware of what a lift off looks like on the data and
           see if there's not something you can do about it.  
                       MEMBER WALLIS:  How long does it take to
           do this inspection?  Have you got something which is
           going around and traversing on some track?
                       MR. MATTHEWS:  It's a robot arm typically
           that hangs off the vessel.  It is done simultaneously
           with the belt line weld exams on the vessel by the ten
           year ISI.  And it will go in and has a sled that will
                       MEMBER WALLIS:  Is this a day long
           operation type thing?  
                       MR. MATTHEWS:  I imagine it's at least
           that.  I'm not sure how long it takes.  Not per nozzle
           I would imagine it wouldn't take all day.
                       MEMBER SIEBER:  About 12 hours including
           moving into position.
                       MR. MATTHEWS:  Per nozzle.
                       MEMBER WALLIS:  Presumably the signal --
           everything comes out as stored information so it's
           available  at any time. 
                       MR. MATTHEWS:  For these particular
           nozzles and these particular welds it is.  There's
           other inconel welds that are not done today with
           automated techniques where that's not true.   But for
           these hot leg and the cold leg nozzles off the vessel,
           those are typically automated exams from the ID. 
                       Back on the, well I guess I've mentioned
           the three plants that have inconel welds that are
           doing 10 year vessel ISIs we understand geometry is a
           very big issue here, the ID geometry in the contact of
           the sleds.  Looking at it, those three plants, the
           inconel weld was a shop weld not a field weld and we
           firmly believe that the ID geometry for the inconel
           part of this weld will be in much better shape than
           the situation at Summer.  I'm not sure we have ID
           contours but typically those shop welds are in much
           better shape when we ID than the field welds.  
                       MEMBER SHACK:  Can you try to finish up in
           five minutes?
                       MR. MATTHEWS:  Oh, okay I'll hurry.
                       Other things that we're recommending is
           that we enhance the sensitivity of the boric acid walk
           down and enhance the awareness of the operations and
           chemistry people looking for small changes and
           unidentified leakage and possible, or notifying them
           where these 82/182 welds are. 
                       Longer term actions of the inspection
           committee, they need to evaluate the need for
           alternative and new techniques and we'll be doing
           that.  We'll be looking at the evolving capabilities
           of the vendors over the years and what new techniques,
           if applicable, could be applied.
                       We'll be looking internationally at what
           techniques are available.  There may be something
           overseas that some of those vendors are using, and we
           realize we have to address in the little bit longer
           term the geometry concerns for the ID.  
                       We'll evaluate the data we get out of the
           spring outages and feed that back in to the fall
           plants for further recommendations.
                       Also, we'll be defining what additional
           mock-ups are needed.  We'll work with the vendors on
           delivery systems, such as the smaller transducer
           packages or better articulating tools, and coordinate
           the demonstration of capabilities with the PDI -- as
           they're developing their mock-ups for qualification of
           inspectors.  That's a fall 2002 requirement that
           bimetallic or dissimilar metal welds be examined by
           qualified people. 
                       And then through the NDE center we'll be
           providing training and expert help where it's needed.
                       And, finally, evaluate the impact on risk
           informed ISI.  
                       But the industry experience is an integral
           part of that risk informed ISI process, so experience
           here will have to be factored in, and there's a
           required feedback loop in the risk informed ISI
           process that takes industry experience and phases it
           back in and into the program for those plants that
           have already implemented risk informed ISI.  And
           they'll have to be assessing that impact on their
                       Finally, the repair and mitigation
           committee's running a little bit behind the others. 
           It's not quite as urgent for us to be addressing that. 
           They'll be meeting in March and they will assess the
           need for improvements in the repair and mitigation
           processes.  That will depend to some extent on what
           comes out of the assessment in the inspection
                       What the repair group will be looking at
           will be prioritizing the locations based on repair
           mitigation inspection perspective which could be quite
           different than a safety perspective.  They'll look at
           the likelihood and consequences of a failure or a
           leak, how difficult is it to implement a repair,
           trying to assess where we might need to work with
           vendors to come up with better ways to repair or
           mitigate the situation.
                       They're going to create a matrix by
           assessing the existing technology, look at what would
           be involved in the qualification and demonstration of
           a new technique, and where there's any kind of code or
           regulatory compliance or involvement, we'll be getting
           the NRC and the code people involved early in the
           development of those processes. 
                       What is our schedule?  We've scheduled a
           technical working meeting with the NRC on March 23. 
           In that meeting we will be going over the detailed
           approach of the short term safety assessment and
           hopefully by that time we will have many if not all of
           the results available, possibly  not in their final
           form.  And we'll solicit their feedback on that short
           term safety assessment.  The plan is to get that to
           them by the end of the month.  
                       We're trying to arrange a visit to the NDE
           center by the staff.  We'd be working with the staff
           and, as Gene said, the staff has already been down and
           audited the demonstration of the technology, or the
           inspection tools at FTI.  
                       The short term assessment inspection to be
           completed in March.  The inspection guidance, like I
           said, I believe that was issued yesterday.  Longer
           term, the assessment inspection efforts for June time
           frame involve evaluation of the spring 2001 inspection
           results and assessment of all the 82/182 welds in the
           plant, in the primary system, not just the ones that
           we think might be the most likely. 
                       And then even longer term there'll be
           continued assessment of all the Alloy 600 applications
           inspection and repair mitigation technology and
           whatever research efforts we and the staff have to
           come up with.  
                       Finally, in conclusion, MRP has taken the
           lead for the industry in developing an industry plan
           here.  We firmly believe this is not really a near
           term safety issue because of the margin available in
           these welds to failure of the piping.  Visual
           inspections for boric acid have been effective and
           they are effective at finding leaks before there's any
           structural integrity threatened.  Pipe welds are
           covered by defense and death approach has been
           inherent in the nuclear industry all along, and we're
           performing the short term assessment to demonstrate
           that we can continue to operate.  
                       MEMBER WALLIS:  I want to ask you about
           this effectiveness.  Now at Summer, boric acid was
           used to find the leak, right. 
                       MR. MATTHEWS:  Yes.
                       MEMBER WALLIS:  Suppose it had not been
           found for another period of time, how long can it go
           on before something worse happens? 
                       MEMBER POWERS:  One, two, or more cycles.
                       MR. MATTHEWS:  The leak at V.C. Summer was
           through a very, very small pin hole where the crack
           had finally made it to the OD and it was a very, very
           small leak. It was 1.2 GPM.  Before the crack gets
           anywhere near a crack size that could threaten a
           rupture of the pipe, you'll be leaking tens of gallons
           of water per minute and you'll easily pick that kind
           of thing up. 
                       MEMBER WALLIS:  Yes, but that's not really
           addressing the first question.  I mean are you saying
           more visual inspections are effective, they're only
           going to be effective if they're caught on time, early
           enough.  And if you inspect and you don't see boric
           acid and then you wait for so long, it must not grow
           in that period of time.  How fast is it, I don't have
           a feel for how fast it would grow if you hadn't
           detected it.
                       MR. WAGONER:  Cycles and cycles and
                       MEMBER WALLIS:  Many cycles before there's
           a big leak?  
                       MR. WAGONER:  Yes, sir.  I'm Vaughn
           Wagoner from Carolina Power and Light.  And the point
           is that the, and I'm going to use some round numbers,
           but a half an inch a year, okay, three-quarters of an
           inch for an 18 month cycle. So you've got two or three
           inches of weld metal in axial direction and it's going
           to stop on both ends, theoretically you could run for
           ever.   So you've got numbers of two, three inches
           that you'll be able probably to have a discernible
           leak and you've got even in the circumferential
           directions you've got tens of inches of flaw
           capability before you ever get there.
                       So you've got cycles and cycles and cycles
           of margin, even if you're in a circumferential
           direction, which is the only one we're really worried
           about it for a catastrophic failure.  And those are
           round numbers, but I think it's the order of
           magnitude, I mean it's in the ballpark of what we're
           talking about.  
                       MEMBER WALLIS:  Is that something the --
           agrees with.
                       MR. WICKMAN:  Keith Wickman, NRR. 
           Critical crack size both axially and circumferentially
           are very large.  Okay.  So on the face of it, yes.  
                       VICE CHAIR BONACA:  So really boric acid
           will be identifying those before leakage? 
                       MR. MATTHEWS:  No.  The boric acid comes
           from the leak.  
                       VICE CHAIR BONACA:  No, I understand that,
           I'm saying that you would find it through an
           inspection, walking down, you see boric acid and
           that's on inspection before you find it through
           unidentified leakage.  What you're telling me is that
                       MR. MATTHEWS:  That's a distinct
           possibility.  That's exactly what happened at V.C.
                       VICE CHAIR BONACA:  Because the growth is
           so slow.
                       MR. MATTHEWS:  That's exactly what
           happened at V.C. Summer.  And we do boric acid walk
           downs every outage and they're pretty thorough and
           we're enhancing the awareness of the people that are
           doing those boric acid walk downs to be sure you trace
           it back and don't assume it was a valve.  Trace it
           back and make sure you know where it's coming from. 
           That kind of thing.  So if there is a leak and it's
           been going on for any -- or leaked out any significant
           amount of boric acid, we feel quite confident that
           we'll find those on the walk downs. 
                       MEMBER SHACK:  Coming back to Graham's
           question though a little bit, I mean circumferential
           cracks are a little more difficult to deal with
           because when you have stress corrosion cracking and
           you have residual stress pattern, you can at least in
           fusion systems where you get very large aspect ratio
           cracks, and he's certainly right that if you get a
           through wall crack of X inches it will take you a long
           time to grow that way.  
                       If the crack is sort of growing at a very
           large aspect ratio when it comes through the wall,
           then things can get more exciting, which is why the
           NRC hasn't allowed leak-before-break in systems that
           have been susceptible to stress corrosion cracking.
                       MEMBER WALLIS:  Aspect ratio I mean
           there's a long base to the crack, a little tip up here
           so --
                       MEMBER SHACK:  Well, relatively shallow
           and a long length.  The axial flaw are really much
           easier because they do, they butt up against the
           stainless steel on the one end and the ferritic vessel
           on the other, and they're sort of stuck there.  
                       MEMBER WALLIS:  Are they stopped forever
                       MEMBER SIEBER: Pretty much. 
                       MEMBER SHACK:  Forever as long as, you
           know, on the scale that we're interested in things,
                       MR. MATTHEWS:   And we'd certainly find
           those before they corroded away the nozzle from boric
           acid from the OD I think.  
                       Interim inspection guides for near to term
           plants has been issued.  We will revise that later as
           we get more information, as we have better handles on
           technology.  The longer term assessment in the Alloy
           600 and 182 and 82 welds in the PWR primary system and
           including inspection repair and mitigation, we'll be
           looking at all these things in a little longer term
           and we intend to keep the NRC staff fully informed of
           everything we do and as we're going along.
                       Basically, any more questions.  Did I do
           it in five?  
                       MEMBER SHACK:  Close enough.  
                       MR. MATTHEWS:  Okay.
                       MR. BATEMAN:  This is Bill Bateman from
           the staff.  If you don't mind I'd like to make a
           couple of comments quickly because I know it's getting
           close to lunch time.  
                       I'm the chief of the branch that had to
           make the decision as to what to do as the result of
           can Summer restart or not.  And at least from a code
           perspective, the affected weld was totally replaced so
           we got out of the code realm when they cut the whole
           weld out and put in a whole new weld.  So from that
           perspective Summer was in compliance with the code. 
                       Regarding the other two indications on the
           cold leg, those welds, even assuming a 2:1 aspect
           ratio did not achieve 10 percent depth in the pipe,
           which would have required a flaw analysis by the code. 
           So by code requirements there is no requirement to do
           a flaw analysis because the assumed depth of that eddy
           current indication was not at a 10 percent depth. 
                       However, we took the bounding crack growth
           rate and applied it to the one-eighth inch assumed
           depth to that crack to assure that that crack would
           not exceed the 75 percent through wall.  And the time
           we came up with was about one cycle.  
                       So those are the conservatisms that the
           staff used in coming to the conclusion that it would
           be all right for Summer to restart.  I want to try and
           firm that up.  There seems to be some skepticism I
           think in terms of our rationale.  
                       So, again, in terms of the code, there was
           never an issue with code.  Everything was totally in
           compliance with the code, we went beyond the code and
           basically with the bounded crack growth rate analysis
           to make our determination.  
                       And, again, with respect to the crack
           growth rate analysis, there's not a lot of data, but
           the data we did have we reviewed with our own
           expertise and we went to National Lab and got their
           advice in terms of whether or not this was a valid
           crack growth rate, and whether or not our assumptions
           were valid.  And all the feedback we got led us to use
           the data that we did with confidence that we would not
           have a problem prior to an inspection after one cycle
           of operation.  
                       MEMBER SHACK:  Any additional comments? 
           No.  Mr. Chairman. 
                       VICE CHAIR BONACA:  With that I think we
           will take a break for lunch and we will come back at
           one o'clock.  
                       (Whereupon, the above-entitled matter went
           off the record at 11:56 a.m.)
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