Additional Guidance on "Potential for Low Fracture Toughness and Lamellar Tearing on PWR Steam Generator and Reactor Coolant Pump Supports" (Generic Letter 80-47)
May 20, 1980
ALL PENDING OPERATING LICENSEES AND CONSTRUCTION PERMIT APPLICANTS ALL
LICENSEES OF PLANTS UNDER CONSTRUCTION
Subject: ADDITIONAL GUIDANCE ON "POTENTIAL FOR LOW FRACTURE TOUGHNESS AND
LAMELLAR TEARING ON PWR STEAM GENERATOR AND REACTOR COOLANT PUMP SUPPORTS",
In November 1979, you were sent for your review and comment the "For
Comment" edition of NUREG-0577, "Potential for Low Fracture Toughness and
Lamellar Tearing on PWR Steam Generator and Reactor Coolant Pump Supports".
The report provides the staff's resolution of the NRC's Generic Technical
Activity No. A-12, which is an "Unresolved Safety Issue" pursuant to Section
210 of the Energy Reorganization Act of 1974.
The generic study resulted from questions raised during the licensing review
of two pressurized water reactors. The specific concern was the capability
of the supports to maintain their structural integrity under accident
NUREG-0577 describes the technical issues, the technical studies performed
by an NRC consultant, the NRC staff's technical positions on fracture
toughness based on these studies, and the staff's tentative plans for
implementing its technical positions. It also provides recommendations for
further generic research into the subject of lamellar tearing. The Electric
Power Research Institute has been requested to conduct such research.
Comments on the report, including the proposed review procedure and
implementation schedule contained in this letter, are being solicited from
interested organizations, groups, and individuals. These comments will be
evaluated by the NRC staff prior to final implementation of this subject.
All comments should be forwarded to Mr. Richard P. Snaider, Generic Issues
Branch, Nuclear Regulatory Commission, Washington, D.C. 20555 by July 7,
At the completion of the comment period, the staff will evaluate the
comments received and, if needed, will issue a supplement of revision to
NUREG-0577. The target for issuing the supplement or revision is late
Subsequent to the issuance of NUREG-0577, the NRC has decided to modify
significantly the implementation plan presented in Section 4 of NUREG-0577.
Basically, the staff proposes that BWR and PWR applicants be required to
demonstrate the adequacy of the applicable support structures of their
facility(ies) from a fracture toughness standpoint. Applicable support
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Reactor coolant recirculation pumps
Reactor coolant pumps
The proposed review will proceed as follows:
1. Applicants of plants without a construction permit must use materials
that conform to guidelines of the forthcoming revision to the NRC
Standard Review Plan, which is tentatively scheduled for issuance in
2. Applicants of plants with a construction permit but without operating
license must also use acceptable materials as defined in the SRP.
However, if it can be demonstrated to the staff that implementing the
guidelines of the SRP would result in an undue hardship, the Operating
Reactor Review procedure of Enclosure 1 may be used. For plants
receiving operating licenses prior to December 31, 1980, the review
need not be completed before commencement of operating.
3. Applicants who anticipate receiving an operating license for their
facility (ies) prior to December 31, 1981, must complete the evaluation
of 2. above and submit a detailed report by December 31, 1982, to the
Director of the applicable regional office of the NRC's Office of
Inspection and Enforcement (OIE), with copies to Director, OIE and
Director, Office of Nuclear Reactor Regulation. If the evaluation "as
shown the fracture toughness of any support materials to be inadequate,
the applicant must recommend appropriate action and provide a schedule
for such action.
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4. Applicants who anticipate receiving an operating license after December
31, 1981, must complete the required evaluation prior to licensing and
submit the results as part of an amendment to the Final Safety Analysis
Darrell G. Eisenhut, Director
Division of Licensing
Office of Nuclear Reactor Regulation
"General Operating Reactor
Review Procedure and
cc: Service Lists, w/encl.
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