ML12157A310

Part 21 Interim Report - Steam Generator Tube Wear

ML12157A310
Person / Time
Site:	San Onofre
Issue date:	06/04/2012
From:	Kadokami E Mitsubishi Heavy Industries, Ltd
To:	Office of Nuclear Reactor Regulation
References
47833
Download: ML12157A310 (4)

Text

0610412012 U.S. NuclearRegulatory Commission OperationsCenter Event Report PazelI Part 21 (PAR) Event# 47833 Rep Org: MITSUBISHI HEAVY INDUSTRIES, LTD. Notification Date I Time: 04/13/2012 15:58 (EDT)

Supplier: MITSUBISHI HEAVY INDUSTRIES, LTD Event Date / Time: 02/21/2012 (EDT)

Last Modification: 06/04/2012 Region: 1 Docket #:

City: ARLINGTON Agreement State: Yes County: License #:

State: VA NRC Notified by: El KADOKAMI Notifications: BLAKE WELLING R1DO HQ Ops Officer: JOHN KNOKE KATHLEEN O'DONOHUE R2DO Emergency Class: NON EMERGENCY DAVID HILLS R3DO 10 CFR Section: VINCENT GADDY R4DO 21.21 (a)(2) INTERIM EVAL OF DEVIATION PART 21 GROUP EMAIL PART 21 INTERIM REPORT - STEAM GENERATOR TUBE WEAR This interim Part 21 is in regard to San Onofre Nuclear Generating Station, Unit 2, Steam Generator replacement.

"During the first refueling outage following steam generator replacement, eddy current testing identified ten total tubes with depths of 90 to 28 percent of the tube wall thickness. Some of the affected tubes were located adjacent to retainer bars. The retainer bars are part of the floating anti-vibration bar (AVB) structure that stabilizes the u-bend region of the tubes.

"Other tubes in the two steam generators had detectable wear associated with support points elsewhere in the AVB structure. Each steam generator has 9727 tubes with an 8 percent (778 tubes) design margin for tube plugging.

"Discovery Date: February 13, 2012 "Evaluation completion schedule date: May 31, 2012" "Those Mitsubishi Heavy Industries customers potentially affected by this issue have been notified and will receive a copy of this interim report."

Reference Document: UET-20120089 Interim Report No: U21-018-IR (0)

Notified R1 DO (Joustra), R2DO (Nease), R3DO (Peterson), R4DO (O'Keefe), and Part 21 Group via email.

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06/04/2012 U.S. NuclearRegulatory Commission OperationsCenter Event Report Paze Part 21 (PAR) Event# 47833

• • • UPDATE FROM MITSUBISHI HEAVY INDUSTRIES, LTD VIA FAX ON 6/4/12 AT 1145 EDT * -

• The vendor changed the number of tubes identified with wear depths of 90 to 28 percent from ten tubes to six tubes and only some of the tubes were adjacent to,'retainer bars.

Notified R1 DO (Cahill), R2DO (Vias), R3DO (Passehl), R4DO (Gepford) and Part 21 Groups via email.

06/04/2012 MON 11i49 FAX 703 908 8041 MNES U0o1/o04 iRITSUBISHI HEAVY INDUSItUES, LTD.

U.S. Nublear Regulatory Comihissjbn Ref: UET-20120089"Revlsion f Attn: Dov6ument control Desk Date: Jun.e 1,, 2012 Wpshington, DC 20555-0001 Sublect: Interim Report of Evaluation of

• Dfvlatlon Pursuant to 10 CFR 21.21.1()(2 Mitsubishi Heavy Industries, 1-TD. (MHI) has identified steam generator tube wear adjacent to retainer bars during the first refuellhg outage.

Tfhe following Information is'provided pbrsuant to tlie requirements of 10 CFR 21 to submit an Interim report on issues for which the eValuation will 'not be conpleted wlthih-d0 days, of discovery An intelim report on .the ,evaluatlon Is attached, spe6ifiuaIl.;, Interim Report No, U21-018-IR R:evision 1. where revisions at u21 O18-JR Revision 1 atre,

1) Changed ¶tieO

2) Chapged "Nature of Deviationr acoedifng to title chiange

3) Changed "ETvaluatioh campi.tion schedule date'"

Those MHI custofmers potentially affeoted by ibis Issue have been hotified and will receive: a copy of this InterHi report.

Yours very truly, Ei Kadokaml Senior Vice Prosident DeputyHead of Nuclear Energy Systems Head of.Kobe -Shipyard & Machinery Works Mitsubishi Heavy Industries, Ltd,

06/04/2012 MON 11:49 FAX 703 908 8041 MNES 2002/004 Attachment to UET-201 20089 Revision 1 Interim Report U21 -01 8-lR Revision 1 Page 1 of 1

Subject:

Interim Report of evaluation pursuant to 10 CFR 21.21 (a) (2)

Title:

Steam generator tube wear adjacent to retainer bars Identiftation ot B*sic Component:

Replacement Steam Generators for-San Onofre Nuclear Generating Station Unit 2 Basle Component $upplied by:

Mitsublshl Heavy industries, LTD.

Nature of Devlatlon:

During the first refueling outage following steam generator replacement, eddy current testing identified six tubes with Wear depths of 90 to 20 percent of the tube wall thicqRtness In Unit 2.

These affected tubes with wear depths of 90 to.28, paercent were located adjacent to. retainer bars.

The retainer bars are iart. of the floating. anti-vibration bar' (AVB) structure that stabilizes the u-bend reglon of the tubes.

Each s..team generat.r has .9727 tubes with an 8 percent (778 tubes) design margin for tube plugging.

Dlscovery Date: February 13, 2012 EValuation conmpletlon. schedule date; August 31, 2012