ML20236K313

Forwards SER Accepting Licensee 971201 & 980624 Confirmation of Revised Feedwater Nozzle Crack Growth Analysis for Fermi Unit 2

ML20236K313
Person / Time
Site:	Fermi
Issue date:	07/01/1998
From:	Wichman K NRC (Affiliation Not Assigned)
To:	Hannon J NRC (Affiliation Not Assigned)
Shared Package
ML20236K316	List: ML20236K313 ML20236K326
References
GL-81-11, TAC-MA0211, TAC-MA211, NUDOCS 9807090273
Download: ML20236K313 (2)

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5 j NUCLEAR REGULATORY COMMISSION

! WA8HINGTON, D.C. 30666 4001 4

9 g ,o July 1, 1998 MEMORANDUM TO: John N. Hannon, Project Director Project Directorate lil-1 Division of Reactor Projects 111 & IV FROM: Keith R. Wichman, Chief Section A Materials and Chemical Engineering Branch Division of Engineering

SUBJECT:

FERMI 2: CONFlRMATICN OF FEEDWATER NOZZLE CRACK GROWTH ANALYSIS Licensee: Detroit Edison TAC No.: MA0211 Review Status: Complete By letter dated December 1,1997, as supplemented by letter dated June 24,1998, the licensee i submitted confirmation of a revised feedwater r ozzle crack growth analysis for Fermi Unit 2.

The information was in response to an NRC request for confirmation of the revised analysis with new operating data on thermal cycles. The NRC also requested that the licensee submit the analysis for review six months prior to the end of 12 operating years.

The original analysis demonstrated that the postulated crack would grow to 1.0 inch in 8.9 operating years. The licensee used estimated or assumed thermal cycles since, at the time, actual data were unavailable. The crack growth analysis did not satisfy the Generic Letter (GL) 81-11 criterion of limiting growth of a postulated 0.25 inch deep crack to a depth no greater than 1.0 inch in'40 years.

The licensee used actual thermal cycle data for a revised analysis, and demonstrated that the postulated crack would grow to a 1.0 inch depth in 38.3 years. Since the analysis results were close, but did not satisfy the criterion in GL 81-11, the staff dMermined that the overall /

methodology was acceptable; but confirmation of the analysis is required. The licensee also committed to follow the feedwater nozzle inspection schedule and examination specified in NUREG-0619 in order to monitor the structural Integrity of the feedwater nozzles in the interim. I. b The current submittalincludes additional operating thermal cycle data. The analysis of the new data resulted in a new cycle projection and an estimated crack growth to 0.8 inches in 40 years of plant operation. This is less than the growth limit in GL 81-11.

79mm Tq CONTACT: A.D. Lee, NRR SdC UI.M C , h-s M U (301) 415-2735 9007090273 DR 9807o1 p ADOCK 05000341 PDR

8 John N. Hannon 2 l' Based on evaluation of the submittal, the staff concludes that the confirmation of the revised l feedwater nozzle crack growth analysis is acceptable and satisfies the criterion in GL 81-11.

Our evaluation is submitted as Attachment 1 and our SALP input is submitted as Attachment 2.

This completes our efforts for TAC NO. MA0211.

Docket Nos.: 50-341 Attachments: As stated t

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l SSheng G:\ LEE \FERMl_FW.WPD To receive a opy of this document. Indicate in the box C= Copy w/o attachment / enclosure E= Copy with attachment / enclosure N = No copy OFFICE DE:EMCB h DE:EMCB E DE:EMCB 6 NAME Alee b BElliot AJO KWichman hhbh DATE 6M/98 7/ //98 7// /98 Md l

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