PNO-I-06-011, Peach Bottom, Unit 2, Loss of Containment Integrity Due to Leak in a Test Return Line
| ML062830345 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 10/10/2006 |
| From: | Fred Bower, James Trapp NRC Region 1 |
| To: | |
| Trapp J RGN-I/DRP/PB4/610-337-5186 | |
| References | |
| PNO-I-06-011 | |
| Download: ML062830345 (3) | |
DCS No.: 05000277100706 Date: October 10, 2006 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-I-06-011 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region I staff on this date.
Facility Peach Bottom Atomic Power Station Delta, PA Docket: 05000277/278 Licensee Emergency Classification X Notification of Unusual Event Alert Site Area Emergency General Emergency
___Not Applicable
SUBJECT:
LOSS OF CONTAINMENT INTEGRITY DUE TO LEAK IN A TEST RETURN LINE On October 7, 2006, at 6:02 p.m., a discretionary Unusual Event was declared at Peach Bottom Unit 2 as the result of a loss of primary containment integrity. The loss of primary containment integrity was caused by an approximately 3.5-inch axial crack in the shared High Pressure Core Injection/Reactor Core Isolation Cooling (HPCI/RCIC) full-flow test return line to the torus. At the time of the event, power was being held at approximately 22 percent to conduct a RCIC full-flow test to the torus following the refueling outage. An operator in the torus room identified water leaking from a 45-degree elbow located just outside the torus penetration. Upon discovery, the RCIC full-flow test was terminated and the full-flow test isolation valve was closed. Closing this valve isolated water to the test line, terminating the leak. However, there is no isolation valve between the torus and the crack in the elbow, so primary containment integrity could not be maintained.
In accordance with Technical Specifications, the plant was shut down and reached Mode 4 (cold shutdown) at 5:13 a.m. on October 8, 2006. Upon reaching cold shutdown, containment integrity was no longer required and the plant exited the Unusual Event.
Visual inspection of the external surface of the 45-degree elbow identified two, 3.5-inch axial cracks on the intrados radius. The degraded elbow was removed and a repair was completed to replace the elbow. The licensee conducted an extent-of-condition review of other similar high-flow torus penetrations at Unit 2 and the similar penetration at Unit 3. No other degraded piping was identified. After completion of the repair and extent of condition review, the licensee commenced a plant startup on October 9, 2006, at 1:35 p.m.
On October 7 and 8, 2006, Exelon issued press releases documenting a factual summary of this event. There has been limited media interest. The States of PA and MD were notified by the licensee as required following the unusual event emergency declaration.
This preliminary notification is issued for information only and no further action by the staff, other than routine inspection follow-up, is anticipated. Since the test return line has been replaced and the plant has started up, this Preliminary Notification will not be updated.
Preliminary Notification Region I, located in King of Prussia, PA, received initial notification of this occurrence by a telephone call from the control room at 6:14 p.m. on October 7, 2006. The information herein has been discussed with the licensee, and is current as of 1:00 p.m. on October 10, 2006.
ADAMS Accession Number: ML062830345 CONTACT:
James M. Trapp Fred Bower JMT1@nrc.gov FLB@nrc.gov (610) 337-5186 (717) 456-7614
Preliminary Notification DISTRIBUTIONS:
BY E-MAIL:
OWFN TWFN Chairman Klein Comm. McGaffigan Jr.
NMSS Comm. Merrifield OIG Comm. Jaczko RES Comm. Lyons OIP OCA OGC EDO OE NRR SECY Regional Offices BY FAX:
DOT:Trans INPO NSAC RI Resident Office Licensee: Exelon Generating Station SUNSI Review Complete: TSC (Reviewers Initials)
DOCUMENT NAME: E:\\Filenet\\ML062830345.wpd OFFICE RI/DRP RI/ORA RI/DRP NAME JTrapp/TCS NSheehan/NAS BHolian/DCL for DATE 10/10/06 10/10/06 10/10 /06 OFFICIAL RECORD COPY Region I Form 83 (Rev. July 2, 2003)