ML20154A593

Forwards Proprietary WCAP-11905 & Nonproprietary WCAP-11906, San Onofre Unit 1 Steam Generator U-Bend Tube Fatigue Evaluation, Per NRC Bulletin 88-002.Westinghouse Application Also encl.WCAP-11905 Withheld (Ref 10CFR2.790)

ML20154A593
Person / Time
Site:	San Onofre
Issue date:	08/30/1988
From:	Pilmer D SOUTHERN CALIFORNIA EDISON CO.
To:	Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML13330B376	List: ML20154A593 ML20154A635
References
IEB-88-002, IEB-88-2, NUDOCS 8809130025
Download: ML20154A593 (2)

Text

. _ _ _ - _ _ - _ _

t r .

o

- Southem CsI/fomia Edison Company P O BCX 800 2244 W ALNUT GROVE AVENUE ROSEME AD. C ALIFORN' A 91770 m .. . . we u .. . .. .. . . ...

August 30, 1988 U. S. Nuclear Regulatory Comission Office of Inspection and Enforcement Region V Walnut Creek, CA 94596-5368 Attention: Mr. John B. Hartin, Regional Administrator

Subject:

Cocket No. 50-206 NRC Bulletin 88-02 San Onofre Nuclear Generating Station Unit 1

References:

1) NRC Bulletin 88-02, "Rapidly Prooagating Fatigue Cracks In Steam Generator Tubes," February 5, 1988

2) Letter, M. O. Medford (SCE) to J. B. Martin (NRC-Region V),

Docket No. 50-206, April 6, 1988 Reference 1 requested that Southern California Edison (SCE) implement actions specified therein to minimize the potential for a steam generator tube rupture event caused by a rapidly propagating fatigue failure such as occurred at North Anna Unit 1 on July 15, 1987. Reference 2 provided SCE's planned actions and schedule in response to the requests in NRC Bulletin 88-02, as they apply to San Onofre Nuclear Generating Station, Unit 1 (SONGS 1).

The purpose of this letter is to provide you with an analysis of the susceptibility of the SONGS 1 steam generators to the North Anna failure and to provide the status of SCE's actions in 'his area.

Enclosed are 1) WCAP-11905, "San Onofre Unit 1 Steam Generator U-Bend Tube Fatigue Evaluation' (Proprietary) and 2) WCAP-11906, "San Onof re Unit 1 Steam Generator U-Bend Tube Fatigue Evaluation" (Non-Proprietary). Also enclosed is a Westinghouse Application for Withholding, CAW-88-076, Accompanying Affidavit, and Proprietary Information Notice. The evidence presented in the enclosca report concludes that the maximum cumulative fatigue usage factor for a 30 year operating period (Design Life of the SONCS 1 steam generators) is calculated to be 0.088 for the unsupported tube with the highest stress (i.e., a stress ratio of 0.7). This usage factor is lets than 1.0 and consequently this worst case tube and all other tubes are acceptable for continued service. pg i

8809139025 000030 hrt. Exc.

PDR ADOCK 05000206 C+bCsEt L##R G PNV l /A#

NSIC l paf HRt pp I /W

0 Mr. J. B. Martin August 30, 1988 As this submittal contains information proprietary to Westinghouse Electric Corporation, it is supported by an affidavit signed by Westinghouse, the owner of the information. The affidavit sets forth the basis on which the information may be withheld from public disclosure by the Comission and addresses with specificity the considerations listed in paragraph (b)(4) of Section 2.790 of the Comission's regulations.

Accordingly, it is respectfully requested that the information which is proprietary to Westinghouse be withheld from public disclosure in accordance with 10 CFR Section 2.790 of the Comission's regulations. Correspondence with respect to th? proprietary aspects of the Application for Withholding or the supporting Westinghouse affidavit should reference CAW-88-076 and should be addressed to R. A. Wiesemann, Manager Regulatory and Legislative Affairs, Westinghouse Electric Corporation, P. O. Box 355, Pittsburgh, PA 15230.

Reference 2 comitted SCE to a short-term enhanced primary to secondary leak rate monitoring program and a longer-term modification to the air ejector monitor. Based upon the results of the enclosed analyses, the modification to the air ejector monitor would not be required in response to NRC Bulletin 88-02. However, although not required, it is SCE's intention to implement this modification to provide the operators with real-time steam generator leakage information. The enhanced primary to secondary leak rate monitoring program discussed in Reference 2 will be implemented through the riext refueling outage, currently scheduled to start in November 1988. However, it is not planned to continue the enhanced leak rate program beyond the end of the refueling outage.

If you have any questions or require additional information, please let me

! know.

Respectfully submitted, M,

By: $(/ j /,'/

f' frM % /

l 0. F. }ilmer~

Manager, Nuclear Engineering l

l Subscribed and sworn t ,e.before me this AO k day of Llu m b M $.

OFFICIAL SEAL

(/ C. SALLY SE00

/

., CLb w  ;

LN LES C W com tio wo. m Notary Public ir(And f or the County of Los Angeles, State of California Enclosures cc: U. S. Nuclear Regulatory Comission, Document Control Oesk F. R. Huey, NRC Senior Resident Insoector, SONG 3 1, 2 and 3 1

i