ML20210K395

Forwards Evaluation of BWR Shroud Cracking Generic Safety Assessment,Rev 1, GENE-523-A107P-0794 & BWR Core Shroud Insp & Evaluation Guidelines, GENE-523-113-0894

ML20210K395
Person / Time
Site:	Pilgrim
Issue date:	12/28/1994
From:	Sheron B NRC (Affiliation Not Assigned)
To:	Beckham J SOUTHERN NUCLEAR OPERATING CO.
Shared Package
ML20210K322	List: ML20210K318 ML20210K355 ML20210K395
References
NUDOCS 9708190240
Download: ML20210K395 (2)

Text

,

' + [~ \ UNITED STATES

..- 4 0 NUCLEAR RECULATORY COMMISSICN y CASHINOTol(. o.C. 30seHoot 5

. , g +o December 28,1994 Mr. J.T. Beckham, Chairman, BWR/ VIP Southern Nuclear Operating Company l 42 Inverness Center Parkway l Birmingham, Alabama 35242

SUBJECT:

EVALUATION OF "BWR SHROUD CRACKING GENERIC SAFETY ASSESSMENT, REVISION 1," GENE-523-A107P-0794, AUGUST 5,1994 and "BWR CORE SHROUD INSPECTION AND EVALUATION GUIDELINES," GENE-523-113-0894, SEPTEMBER E, 1994

Dear Mr. Beckham:

By letter dated August 5,1994, the BWROG submitted the report, "BWR Shroud Cracking Generic Safety Assessment " This report was intended to provide individual BWR licensees with the bases to develop their plant-s socific course of action relative to operation and plant inspection. On Se 13, 1994, the staff issued a request for additional information (RAI) ptem>er concerning the document with a requested reply date of September 23, 1994. Replies from the BWRVIP were received on September 23, 1994 and October 11, 1994 The October 11 reply contained a partial response and indicated that considerable effort would be required to complete the effort. The complete response has not yet been received. f~

By letter dated September 2, 1994, the BWRVIP submitted the report, "BWR Core 4 Shroud Inspection and Evaluation Guidelines." This report provides guidelines for inspection strategy and flaw evaluation and effectively supersedes the August 5, document in these areas. The inspection strategy contained in the report was based on an examination for the minimum amount of intact shroud material required to assure the ASME Code structural margins. By letter dated September 13, 1994, the NRC provided a preliminary assessment of this report which concluded that this strategy was not a prudent way to conduct inspections and that the staff expectation was for examination of all accessible portions of the shroud circumferential welds.

The staff has reviewed the subject reports and has completed the enclosed safety evaluation report. To ex2edite the review process it was decided to complete the reviews with ava11asle information and not wait for the complete response to the RAI on the August 5 report. The staff has found that:

1. Due to the number of variables involved in such analyses an assessment of individual plants through a generic evaluation is not possible; however, the overall methodology utilized for the BWROG consequence assessment is sound and provides useful insights on design specific differences.

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l . 2. - Tha staff review of the inspection guldsnce provided in the document i

• , /~ _ dated September 2, 1994, concluded that the basic philosophy of insp:cting for cinimos sound metal is not a prudent method-for conducting an inspection. NRC's position on this approach was previously stated in the staff's Safety Evaluation of core shroud cracking at Dresden, Unit 3, and Quad Cities, Unit 1. dated

. July 10,1994.

3. Numerous deficiencies were identified in the proposed inspection strategy.- These are described in Section 6.0 of the enclosed Safety Evaluation Report.

4. The staff agrees with the categorization of BWR plants into three groups (Category A 8, or C) based on their relative susceptibility to shroud ICSCC and proposed guidance for establishing schedules for inspections of Category A and B plants.

5. The proposed flaw evaluation methodology is consistent with the methods of Section XI of the ASME Code.

Please address any questions regarding the staff evaluation to Ed Hackett of my staff (301) 504-2751.

Sincerely, OR:D.L SIGNED BY hb.SM, oirector Division of Engineering Office of Nuclear Reactor Regulation

Enclosure:

As Stated cc: Robert A.-Pinelli, Chairman 8WROG 01stribut' q Central- FLlos

. DE/RF KKavanagh KAManaly DBriniusan JMedoff WKoo PPatnaik MPRubin Mayfield JRRajan Concurrence: *$ee Previous Concurrence DOCUMENT NAME: G:\ SHROUD \BWREVAL2.SER to receive e eser of tale essweene, leWicote in the hem Cecepy u/o attachment / enclosure secuw with attachment / enclosure N

• No cet OFFICE DE/EMC8* E- DE/EMC8* E DE/EMCB* C EMC8/C* E NAME PJRushtadl jb D64ackett- RAHerwann JStrosnider mum mmme ummm em

,0FFICF FMEB/C* E SRXB/C* E 00 DE* E Qd 8 NAME RHWessman RCJones Glainas ISkekn _ _. _

DATE 12/12/94 12/18/94 12/20/g4 &/]7/94 0FFICIAL RECORD CJPV l

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