United States Nuclear Regulatory Commission - Protecting People and the Environment

Implementation of Guidance From USI A-12 "Potential for LOW Fracture Toughness and Lamellar Tearing on Component Support (Generic Letter 80-85)



GL80085 

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

                                OCT 06 1980 

Generic Task No. A-12 

All Power Reactor Licensees and Applicants 

Subject:  Implementation of Guidance From Unresolved Safety Issue A-12, 
          "Potential For Low Fracture Toughness and Lamellar Tearing on 
          Component Supports" 

Gentlemen: 

As you are aware, NUREG-0577 (Potential for Low Fracture Toughness and 
Lamellar Tearing on PWR Steam Generator and Reactor Coolant Pump Supports) 
was issued in its "For Comment" form in November 1970. Additional guidance 
regarding implementation was issued by letters dated May 19, 1980 
(licensees) and May 20, 1980 (applicants). A significant difference between 
NUREG-0577 and the criteria contained in the May 19th and 20th letters was 
the removal, in the letters, of the option of using linear elastic fracture 
mechanics analyses to demonstrate adequate structural integrity. The largest 
single response by applicants and licensees to the May 19 and 20 letters 
indicated, a desire to retain linear elastic fracture mechanics analyses as 
an alternative means to demonstrate adequate structural integrity. Because 
of the response received due to this change, the NRC staff convened a 
meeting on August 27, 1980 to resolve the differences In the proposed 
programs. The summary of this meeting is attached. You should especially 
note these items of importance: (1) No action is required on your part at 
this time regarding lamellar tearing; (2) The subject of irradiation effects 
on reactor vessel support materials is under review by the NRC staff and is 
not part of the A-72 effort; and (3) No implementation action on your part 
will be required before the December 1980 meeting. Exceptions to this policy 
may be necessary on a case-by-case basis if significant materials problems 
are found to exist. Of more importance, however, is our request that you be 
prepared to commit to the alternative program if approved by the NRC staff 
at the meeting to be held in December 1980. Failure to commit to the 
alternative program will result in NRC imposition of the guidance contained 
in the May 19, 1980 and May 20, 1980 letters, as modified by applicable 
comments under review by the NRC staff. 

Note also that the recommendation for extension of the implementation period
is still under staff review. A decision will be made prior to the December 
1980 meeting. 
.

All Power Reactor Licensees       - 2 -
and Applicants 

Please refer any questions to Richard Snaider at 301-492-7876. 


                                        Darrell G, Eisenhut, Director 
                                        Division of Licensing 

Enclosure: 
  Summary of August 27, 1980 Meeting 

cc: Service List, w/o attachment 

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