ENS Event | |
|---|---|
06:45 May 14, 2011 | |
| Title | Technical Specification Required Shutdown Due to Inability to Maintain Specified Differential Pressure Between Drywell and Suppression Chamber |
| Event Description | Following startup from RFO [Refueling Outage] 18, at approximately 14% reactor power, PNPS [Pilgrim Nuclear Power Station] was unable to set the conditions required to demonstrate the drywell to suppression chamber decay rate is less than 25% of the differential pressure decay rate for the maximum allowable bypass area of 0.2 ft2 [as required by] TS [Technical Specification] 3.7.A.4(b).
Prior to exceeding 15% power, PNPS Technical Specifications require differential pressure between the drywell and suppression chamber to be greater than 1.17 psid. The licensee was not able to achieve this delta pressure and initiated troubleshooting to determine the cause. A plant shutdown is being initiated to continue this effort. The plant is in a stable condition. Investigation is continuing into the failure to establish test conditions. There is no threat to the health and safety of the public as a result of this condition. The licensee suspects leakby in the Drywell to Torus vacuum breaker but will not be able to verify until the plant is shutdown. The licensee has notified the NRC Resident Inspector and will be notifying the State of Massachusetts. |
| Where | |
|---|---|
| Pilgrim Massachusetts (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | |
| Time - Person (Reporting Time:+-2.22 h-0.0925 days <br />-0.0132 weeks <br />-0.00304 months <br />) | |
| Opened: | Michael Mcdonnell 04:32 May 14, 2011 |
| NRC Officer: | Howie Crouch |
| Last Updated: | May 14, 2011 |
| 46852 - NRC Website
Loading map... | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (14 %) |
| After | Power Operation (14 %) |
Pilgrim with 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | |
WEEKMONTHYEARENS 486852013-01-21T01:50:00021 January 2013 01:50:00
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