United States Nuclear Regulatory Commission - Protecting People and the Environment

Steam Generators-Enclosing Summary Of Operating Experience With Recirculating Steam Generators, NUREG-0523 (Generic Letter 79-15)


GL79015 

                               UNITED STATES 
                       NUCLEAR REGULATORY COMMISSION 
                          WASHINGTON, D.C. 20555 

                              March 21, 1979 

ALL PRESSURIZED WATER REACTOR LICENSEES 

Gentlemen: 

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

Operating problems have occurred in Pressurized Water Reactor (PWR) steam 
generators. The enclosed report, "Summary of Operating Experience with 
Recirculating Steam Generators," NUREG 0523, focuses on the problems 
associated with steam generators of the recirculation type, i.e., those 
manufactured by Combustion Engineering and Westinghouse. The report 
discusses the NRC staff's evaluation of these problems and the programs for 
resolving these problems. 

The NRC has recently identified steam generator degradation as an Unresolved
Safety Issue deserving the highest priority for resolution. However, for the
reasons identified in the report, the NRC staff has concluded that continued
operation of existing plants and licensing of new plants with recirculation 
type steam generators, pending completion of our review, does not constitute
an undue risk to the health and safety of the public and therefore may 
continue. 

It should be noted that a number of research efforts are currently under way
which will improve our knowledge of steam generator our current 
understanding of each issue. Comments on this report and information 
.

                                  - 2 -                     March 21, 1979 

related to steam generator degradation mechanisms are encouraged and should 
be forwarded to Dr. Boen-Dar Liaw, Engineering Branch, Division of Operating
Reactors, U. S. Nuclear Regulatory Commission, Washington, D.C. 20555. 



                                        D. G. Eisenhut, Deputy Director 
                                        Division of Operating Reactors 

Enclosure:
Summary of Operating Experience
  with Recirculating Steam
  Generators, January 1979,
  NUREG 0523

cc w/o enclosure: Service List
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