United States Nuclear Regulatory Commission - Protecting People and the Environment

BWR Scram System (Generic Letter 80-84)


                               UNITED STATES 
                          WASHINGTON, D. C. 20555 

                              October 1, 1980 



On June 28, 1980, during a routine shutdown of the Browns Ferry 3 reactor, a 
manual scram failed to insert all control rods. I&E Bulletin 80-17 with 
subsequent supplements 1, 2 and 3 has been issued which has required system 
modifications, procedural and design verifications, additional surveillance 
and tests, and analyses to assure adequate short-term performance of 
existing scram systems on operating plants. 

However, we believe further hardware and procedural changes will be required 
to assure adequate long-term scram system reliability. We are aware that the
BWR owners have formed a Sub-Group of the BWR Owners Group to address this 
matter and are in the process of developing design and performance criteria.

Therefore, in order to determine whether or not your license should be 
modified, please provide us in writing, under oath or affirmation, within 25
days of the date of this letter your plans for participation in this effort.
In addition, your response should include: 

     (1)  The results of any reassessment of your present scram system to 
          confirm conformance with the General Design Criteria (Appendix A 
          to 10 CFR 50). 

     (2)  Whether you intend to reevaluate your present scram system and 
          modify it as necessary to meet the additional design and 
          performance criteria developed by the Owners Sub-Group. If not, 
          what criteria will be used to judge the adequacy of your present 
          scram system? 

     (3)  Whether you intend to provide by December 15, 1980, the results of
          the above reevaluation (including required modifications) along 
          with a schedule for implementation. If not, why not. 

This information is requested under the authority of 10 CFR 50.54(f) of the 
Commission's regulations. 

If you have any questions concerning this matter, please call your Project 


                                        Darrell G. Eisenhut, Director 
                                        Division of Licensing 

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