ML12109A094

Part 21 Interim Report - Steam Generator Tube Wear

ML12109A094
Person / Time
Site:	San Onofre
Issue date:	04/13/2012
From:	Kadokami E Mitsubishi Nuclear Energy Systems
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
47833, UET-20120089
Download: ML12109A094 (5)

Text

04/13/2012 U.S. Nuclear Regulatory Commission OperationsCenter Event Report Paste I OFFICIAL USE ONLY Part 21 (PAR) Event# 47833 Rep Org: MITSUBISHI NUCLEAR ENERGY SYSTEMS Notification Date / Time: 04/13/2012 15:58 (EDT)

Supplier: MITSUBISHI HEAVY INDUSTRIES, LTD Event Date / Time: 04/13/2012 (EDT)

Last Modification: 04/13/2012 Region: 1 Docket #:

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

State: VA NRC Notified by: El KADOKAMI Notifications: BLAKE WELLING R1 DO 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, 2010" "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)

OFFICIAL USE ONLY 7 ~ j-.

04/13/2012 FRI 14!03 FAX 703 908 8041 MNES u001/00 3

.-MNESA AMI1SUUlHIH IUCLEAIR IENERLGYr SYSTEkS. INC.

1001 19 Street North Arlington, VA 22209 Main: 703.908.8040 Fax: 703.908.8041 Fax Toz 1R- Fromi 6-p ýý IA Few '$ak~ 6) 55 Pages: 7-phone: 'Daft. 'L-03 Urgent KFur Review 0 Please Comment 0 PleassO Reply 0 Plasm. Recycle

04/13/2012 FRI 14:03 FAX 703 908 8041 MNES Q~002/003 A

MITSUBISHI HEAVY INDUSTRIES, LTD.

U.S. Nuclear Regulatory Commission Ref: UET-20.120089 Attn: Document Control Desk Date; Apr. 10, 2012 Washington, DC 20555-0001 SUblect: hnterimn R~ebrt ofEve!u4tlo.

of a Devatln Pursuant to 10 CFR 21.2911(a*(2 Mitsubishi Heavy'industries, LTD. (MHI) has identified tubes with defths of 90% to 289%' of

,tube,wall thickness during the first refueling outage.

The following information is provided pursuant to the requirements of 10.CFR 21 to submit aninterim report on lssues for which the evaluation will not be completed within 60 days, of discovery.

An Interim report on the evaluation is attached, specifically;,.Interim Report No. U21 -01 B-IR.

Those MHI customers potentially affected by this issue have been notified and will receive a copy ofathis Interim report, Yours very truly; Ei Kadokami, Senior Vice President Deputy Head of Nuclear Energy Systems Head of Kobe Shipyard & Machinery Works Mitsubishi Heavy industries, Ltd.

04/13/2012 FRI 14103 PAX 703 908 8041 MNES 2003/003 Attachment to UET-20120089 InterimBeport U211i8-IR (0)

V/1 SubJect; Interim Report of evaluation pursuant to 10 CFR 21.21 (a) (2)

.Title;.Steam generator tube wear a-fter first cycle operation (San Onofre 9)

Idontlflcatlp of Baslc Componeon*:

Replaoement Steam Generators lot San On~ofre Nuclear Gernerating Station Unit 2 BashIc CompOnent $upplied by:

Mitsubishi Heavy Industrles, LTD.

Nature of Deviati.on:

During the first refueling outage following steam generator rep aceonent, eddy current testIng Identified ten total tubes with wear 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 floatlng'anti-vibra~tion bar (A08) structure that stabilizes the u-bend region of the tubes.

Other tubes in the two steam generators had detectable wear associated with support points elsewherein the AVB structure. Each steam generator has 9727tubes

,wi~th an 8percent (778 tubes) design margi n for tube pluggIng.

Discovery Date: February 13, 2012 Evaluation completion schedule dite: May 31, 2012