United States Nuclear Regulatory Commission - Protecting People and the Environment

Additional Guidance on "Potential for Low Fracture Toughness and
Lamellar Tearing on PWR Steam Generator and Reactor Coolant Pump Supports" (Generic Letter 80-47)



GL80047 

                               May 20, 1980 

ALL PENDING OPERATING LICENSEES AND CONSTRUCTION PERMIT APPLICANTS ALL 
LICENSEES OF PLANTS UNDER CONSTRUCTION 

Gentlemen: 

Subject: ADDITIONAL GUIDANCE ON "POTENTIAL FOR LOW FRACTURE TOUGHNESS AND 
LAMELLAR TEARING ON PWR STEAM GENERATOR AND REACTOR COOLANT PUMP SUPPORTS", 
NUREG-0577 

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 
conditions. 

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, 
1980. 

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 
September 1980. 

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 
structures are: 
.

                                  - 2 -

BWR 

     Reactor vessel 

     Reactor coolant recirculation pumps 

PWR 

     Steam generators 
     
     Reactor coolant pumps 
     
     Pressurizer 
     
     Reactor vessel 
     
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 
     June 1980. 

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. 
.

                                  - 3 -

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
     Report. 

                                        Sincerely, 


                                        Darrell G. Eisenhut, Director 
                                        Division of Licensing 
                                        Office of Nuclear Reactor Regulation

Enclosure:
"General Operating Reactor
  Review Procedure and 
  Acceptance Criteria"

cc: Service Lists, w/encl.

DISTRIBUTION
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