The following information was obtained from Mitsubishi Heavy Industries, LTD on April 19, 2012 was inadvertently added to
Event Notification#47833 as an update to that event. The vendor's intent was to issue two interim reports; one for San Onofre Nuclear Generating Station (
SONGS) Unit 2 and one for
SONGS Unit 3. The information was obtained via fax:
On January 31, 2012, San Onofre Unit 3 shut down due to indications of a steam generator tube leak. Steam generator tube inspections confirmed one small leak on one tube in one of the two steam generators. Continuing inspections of 100% of the steam generator tubes in both Unit 3 steam generators discovered unexpected wear, including tube to tube as well as tube to tube support structural wear. Inspection, testing, and analysis of SG tube integrity in both Unit 3 SGs is ongoing. In-situ pressure testing identified eight Unit 3 SG tubes that did not meet the target performance criteria in Technical Specification for tube integrity. One of the failed tubes was the leaking tube that required the Unit 3 shutdown.
Discovery date: February 21, 2012
Evaluation completion schedule date: August 31, 2012
Interim Report: U21-019-IR
Reference Document: UET-20120105
Original notifications (per EN 47833) were made to R1DO (Joustra), R2DO (Nease), R3DO (Peterson), R4DO (O'Keefe), and Part 21 Group via email.
Notified R1DO (Cahill), R2DO (Vias), R3DO (Passehl), R4DO (Gepford) and Part 21 Groups via email.
- * * UPDATE FROM MITSUBISHI HEAVY INDUSTRIES, LTD VIA FAX ON 6/4/12 AT 1145 EDT * * *
The vendor reported that eight Unit 3 SG tubes did not meet the target performance criteria in Technical Specifications for tube integrity.
Notified R1DO (Cahill), R2DO (Vias), R3DO (Passehl), R4DO (Gepford) and Part 21 Groups via email.
- * * UPDATE FROM MITSUBISHI HEAVY INDSUSTRIES, 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.