ENS 47833

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v t e ENS Event
04:00 Feb 21, 2012
Title	Part 21 Interim Report - Steam Generator Tube Wear
Event Description	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 R1DO (Joustra), R2DO (Nease), R3DO (Peterson), R4DO (O'Keefe), and Part 21 Group via email. * * 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 R1DO (Cahill), R2DO (Vias), R3DO (Passehl), R4DO (Gepford) and Part 21 Groups via email. * * UPDATE FROM MITSUBISHI HEAVY INDUSTRIES, LTD VIA FAX ON 9/7/12 AT 1539 EDT * * * MHI evaluated that the deviation contains a reportable defect for San Onofre Nuclear Generating Station Unit 2 and 3. Notified R4DO (Gaddy) and Part 21 Reactor Group via email.

ENS 47833 +/-
Where
Mitsubishi Heavy Industries, Ltd Arlington, Virginia (NRC Region 1)
Organization:	Mitsubishi Heavy Industries, Ltd.
Reporting

10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component
Time - Person (Reporting Time:+1260.97 h52.54 days <br />7.506 weeks <br />1.727 months <br />)
Opened:	Ei Kadokami 15:58 Apr 13, 2012
NRC Officer:	John Knoke
Last Updated:	Sep 7, 2012
47833 - NRC Website
v • d • e

v t e Emergency Notification System
Mitsubishi Heavy Industries, Ltd with 10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component
WEEKMONTHYEAR2012-02-21T04:00:00 [Table view]
[ENS list for Mitsubishi Heavy Industries, Ltd]

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