ENS 46839
ENS Event | |
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19:18 May 9, 2011 | |
Title | Potential Valve Mispositioning Led to a Condition Prohibited by Technical Specifications |
Event Description | On May 9, 2011, at 1518 Eastern Daylight Saving Time (EDT), WBN [Watts Bar Nuclear] started a Safety Injection Pump and began to inject into the Reactor Coolant System contrary to Technical Specification Limiting Condition for Operation 3.4.12, which requires in part for Mode 5 that a Cold Overpressure Mitigation System (COMS) shall be OPERABLE with a maximum of one charging pump and no safety injection pump capable of injecting into the RCS and the accumulators isolated.
The RCS pressure rise was recognized immediately, and the pump was secured within 27 seconds. The pressure reached a maximum of 328 psig. which is below the relief valve setpoint, so no structure, system, or component pressure limit was exceeded at any time. LCO 3.4.12 Condition A was entered immediately. At 1521, the pump breaker was directed to be racked out, and the breaker was reported racked out and verified by 1600, at which time LCO 3.4.12 was exited. This event was determined to be reportable as a condition prohibited by Technical Specifications in accordance with 10 CFR 50.73(a) (2)(i)(b). This notification is made in accordance with Watts Bar License condition 2.G. The NRC Resident Inspector has been notified of this event and event notification. The licensee is investigating the likelihood of a valve mispositioning. |
Where | |
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Watts Bar ![]() Tennessee (NRC Region 2) | |
Reporting | |
Other Unspec Reqmnt | |
Time - Person (Reporting Time:+30.05 h1.252 days <br />0.179 weeks <br />0.0412 months <br />) | |
Opened: | Bill Sprinkle 01:21 May 11, 2011 |
NRC Officer: | Joe O'Hara |
Last Updated: | May 11, 2011 |
46839 - NRC Website
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Unit 1 | |
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Reactor critical | Not Critical |
Scram | No |
Before | Cold Shutdown (0 %) |
After | Cold Shutdown (0 %) |
WEEKMONTHYEARENS 476092012-01-17T22:46:00017 January 2012 22:46:00
[Table view]Other Unspec Reqmnt 24-Hour Report Per Section 2.G of Unit 1 Operating License ENS 468852011-05-14T18:28:00014 May 2011 18:28:00 Other Unspec Reqmnt Violation of License Condition ENS 468392011-05-09T19:18:0009 May 2011 19:18:00 Other Unspec Reqmnt Potential Valve Mispositioning Led to a Condition Prohibited by Technical Specifications ENS 458272010-04-08T04:00:0008 April 2010 04:00:00 Other Unspec Reqmnt Diesel Generators Wired Incorrectly ENS 453312009-09-08T01:20:0008 September 2009 01:20:00 Other Unspec Reqmnt Discovery of After-The-Fact Emergency Condition Unusual Event ENS 426902006-07-07T18:45:0007 July 2006 18:45:00 Other Unspec Reqmnt Alternative Report for Non-Declared Emergency Condition in Accordance with Nureg-1022 ENS 414822005-03-11T19:29:00011 March 2005 19:29:00 Other Unspec Reqmnt It Was Determineded That Greater than 1% of Inspected S/G Tubes Must Be Repaired. ENS 402002003-09-26T12:50:00026 September 2003 12:50:00 Other Unspec Reqmnt Greater than 1 Percent of Steam Generators 1,2 & 4 Tubes Inspected Indicate That the Inspected Tubes Require Plugging. 2012-01-17T22:46:00 | |