Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
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
