United States Nuclear Regulatory Commission - Protecting People and the Environment


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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