IE Circular No. 77-02, Potential Heavy Spring Flooding
CR77002
FEB 15 1977
MEMORANDUM FOR: J. P. O'Reilly, Director, Region I
N. C. Moseley, Director, Region II
J. G. Keppler, Director, Region III
E. M. Howard, Director, Region IV
R. H. Engelken, Director, Region V
FROM: Dudley Thompson, Acting Director
Division of Field Operations, OIE
SUBJECT: IE CIRCULAR NO. 77-02, POTENTIAL HEAVY SPRING
FLOODING
The subject document is transmitted for issuance by close of business
three days after date of this letter. The Circular should be issued to the
holders of Operating Licenses listed on the third enclosure.
Dudley Thompson, Acting Director
Division of Field Operations
Office of Inspection and Enforcement
Enclosures:
1. Circular 77-02
2. Draft transmittal letter
3. List of Operating License
Holders to receive IE
Circular 77-02
.
IE Circular No. 77-02
February 15, 1977
POTENTIAL HEAVY SPRING FLOODING
DESCRIPTION OF CIRCUMSTANCES:
The purpose of this circular is to inform you that the National Weather
Service has predicted that heavy spring flooding in the area from the
Missouri River eastward is likely to occur. Ice covers most of the major
river and lake systems in this area and the accumulation of ice and snow in
the eastern portion has further increased the flooding potential. In some
areas the potential spring flooding may equal or exceed floods of record.
The degree of flooding is dependent upon the rate of warming trends, ice
breakup rates and the occurrence of spring rains. The two enclosed figures
from the National Weather Service indicate the principal frozen rivers and
areas of greatest flood potential in the northeast and upper midwest. There
will also be the possibility of flooding on the Mississippi River below
Cairo, Illinois dependent upon runoff in its tributaries. The enclosed maps
do not address the potential of the associated effects of ice impact and
blockage or additional precipitation on flood related concerns.
ACTION TO BE TAKEN BY LICENSEE:
It is recommended at this time that licensees receiving this circular
reconsider the following items in preparation for potential flooding and the
associated effects at operating facilities.
1. The potential high water level at your facility(ies) caused by runoff
and/or ice jams, coupled with spring rains with respect to the site
flooding conditions utilized in the design of the facility.
2. The potential consequences of ice impacts on exposed structures and
facilities (such as intake structures, trash racks and traveling
screens).
3. The potential for ice blockage in the form of ice blocks, frazil ice
(concentration of ice crystals in the water) and/or anchor ice (bottom
ice) which could hinder the supply of safety related service water.
.
IE Circular No. 77-02 -2- February 15, 1977
4. If any special barriers and/or procedures are needed to offset the
conditions of 1, 2 or 3 above, these should be made ready for
installation and/or implementation if the need arises. In addition,
renewed attention should be given to established procedures or actions
required to mitigate these conditions should they occur. Operating
personnel should review procedures prior to implementation.
5. During the extreme cold weather there is also a potential for loss of
transmission lines due to icing. In addition, should flooding occur
when warmer weather returns the potential for loss of offsite
transmission lines may be increased. Therefore you should evaluate the
adequacy of diesel fuel supplies for onsite power sources. This should
include consideration of whether diesel supply sources and
transportation routes are vulnerable to such flooding and if there is a
need for any additional onsite storage.
6. Based on experience in previous flood conditions, nonsafety related
facilities or components vulnerable to flooding can cause abnormal
plant operations for extended periods of time. Licensees should prepare
for such situations.
At this early date, it is not possible to predict the specific time of
occurrence, location, or extent of flooding or associated effects. Forecasts
regarding flooding or icing can be obtained from the public service
forecasters of the U. S. Weather Service Forecast Center in your state.
These offices are generally open 24 hours per day. The offices (in the
subject area) are advised of river conditions by River Forecast Centers
located in Cincinnati, OH; Harrisburg, PA; Hartford, CT; and Kansas City,
MO.
This circular requires no written reply; however, as needs dictate there may
be further follow-up action by the NRC. This further action may take the
form of site visits to certain facilities for firsthand observation of
existing conditions. If such action is initiated individual licensees will
be contacted in advance.
Approval of NRC requirements for reports concerning possible generic
problems has been obtained under 44 U.S.C. 3152 from the U. S. General
Accounting Office. (GAO Approval B-180255 (R0072), expires 7/31/77).
.
(Transmittal letter for Circular 77-02 to each holder of a NRC Operating
License as listed)
Addressee:
The enclosed Circular 77-02 is forwarded to you for information and
action. If there are any questions related to your understanding of the
actions indicated, please contact this office.
Signature
(Regional Director)
Enclosure:
IE Circular 77-02
.
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D. C. 20555
IE Circular No. 77-02A
Date: February 18, 1977
Page 1 of 2
POTENTIAL HEAVY SPRING FLOODING
DESCRIPTION OF CIRCUMSTANCES:
The purpose of this Circular is to inform you that the National Weather
Service has predicted that heavy spring flooding in the area from the
Missouri River eastward is likely to occur. Ice covers most of the major
river and lake systems in this area and the accumulation of ice and snow in
the eastern portion has further increased the flooding potential. In some
areas the potential spring flooding may equal or exceed floods of record.
The degree of flooding is dependent upon the rate of warming trends, ice
breakup rates and the occurrence of spring rains. The two enclosed figures
from the National Weather Service indicate the principal frozen rivers and
areas of greatest flood potential in the northeast and upper midwest. There
will also be the possibility of flooding on the Mississippi River below
Cairo, Illinois dependent upon runoff in its tributaries. The enclosed maps
do not address the potential of the associated effects of ice impact and
blockage or additional precipitation on flood related concerns.
ACTION TO BE TAKEN BY LICENSEE:
It is recommended at this time that licensees receiving this Circular
consider the following items in preparation for potential flooding and the
associated effects at facilities under construction. Such conditions could
affect safety related structures, systems and components as a result of:
1. Safety related items already in-place and not fully protected.
2. Safety related items in site storage including record vaults containing
documentation of safety related items.
3. Effects of any interconnection to operating units.
At this early date, it is not possible to predict the specific time of
occurrence, location, or extent of flooding or associated effects. Forecasts
regarding flooding or icing can be obtained from the public service
forecasters of the U. S. Weather Service Forecast Center in your state.
These offices are generally open 24 hours per day. The offices (in the
subject area) are advised of river conditions by River Forecast Centers
located in Cincinnati, OH: Harrisburg, PA: Hartford, CT; and Kansas City,
MO.
.
IE Circular No. 77-02A
Date: February 18, 1977
Page 2 of 2
This Circular is provided for your information and requires no written
reply.
Approval of NRC requirements for reports concerning possible generic
problems has been obtained under 44 U.S.C. 3152 from the U. S. General
Accounting Office. (GAO Approval B-180255 (R0072), expires 7/31/77)
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