Reliability of Onsite Diesel Generators at Light Water Reactors (Generic Letter 79-17)


                               UNITED STATES 
                          WASHINGTON, D.C. 20555 

                              April 18, 1979 

Docket Nos.: 50-443/444 

     All Light Water Power Reactor Licensees 


     This letter is being sent to all licensees authorized to operate or 
     construct a light water power reactor and to all applicants for a 
     licenses to operate or construct a light water power reactor. 

     A review of the operating experience of the emergency onsite diesel 
     generators at light water reactors as reported in the licensee Event 
     Reports (1969-1977) indicated that their reliability could be improved.

     The reliability of the diesel generator is strongly dependent on the 
     interaction of the following factors: design, testing and operational 
     requirements, operational history, inspections, maintenance, and the 
     personnel qualifications of operators. To assist us in identifying any 
     significant deficiencies, the University of Dayton Research Institute, 
     under our contract, prepared a report entitled "Enhancement of Onsite 
     Emergency Diesel Generator Reliability" (NUREG 0660) which identifies 
     the major problems together with recommended corrective actions for 
     improving reliability. We will review the report and evaluate each 
     recommendation for its applicability to all licensees authorized to 
     operate or construct light water power reactors and to all applicants 
     for a license to operate or construct a light water power reactor by 
     balancing the potential improvement in reliability versus the adverse 
     impact of implementing the recommendation on the plants. 

     Since our review and evaluation of the report has not been completed we
     are enclosing a copy of NUREG 0660, the University of Dayton Research 
     Institute report, for your information and comments. Comments or other 
     factors which may be considered major problems preventing improved 
     onsite emergency diesel generator reliability are encouraged 

                                  - 2 -

     and should be forwarded to Fred Clemeson, Plant Systems Branch, 
     Division of Operating Reactor, U. S. Nuclear Regulatory Commission, 
     Washington, D.C. 20555. 

                                        D. B. Vassallo, Assistant Director 
                                          for Light Water Reactors 
                                        Division of Project Management 

     NUREG 0660 

     ccs w/o encl:
     See next page 

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