NRC Generic Letter 80-85, Implementation of Guidance From Unresolved Safety Issue A-12, "Potential for Low Fracture Toughness and Lamellar Tearing on Component Supports"

text

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 Licenseesand 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