ENS 48466
ENS Event | |
|---|---|
18:41 Oct 31, 2012 | |
| Title | Both Trains of Standby Gas Treatment System Inoperable |
| Event Description | On Wednesday, October 31, 2012 at 1200 hours0.0139 days <br />0.333 hours <br />0.00198 weeks <br />4.566e-4 months <br />, with the reactor at approximately 100% core thermal power and steady state conditions, Standby Gas Treatment (SBGT) System Train 'B' was removed from service (made inoperable) for surveillance testing.
At 1441 hours0.0167 days <br />0.4 hours <br />0.00238 weeks <br />5.483005e-4 months <br />, the control room staff declared the Standby Gas Treatment System Train 'A' inoperable as a result of an engineering analysis that determined that 480 VAC feed, Motor Control Center (MCC) B15, had the potential to exceed its trip set point under worst case bus loading. The inoperability of both SBGT System Trains 'A' and 'B' could have prevented the fulfillment of the safety functions to 'control the release of radioactive material' and 'mitigate the consequences of an accident.' At 1510 hours0.0175 days <br />0.419 hours <br />0.0025 weeks <br />5.74555e-4 months <br />, a compensatory measure was taken to preclude the overload condition on MCC B15 and the SBGT System Train 'A' was restored to operable status. At the time of submittal of this notification, the SBGT System Train 'B' remains inoperable for replacement of an overload relay. SBGT System Train 'B' is expected to be returned to service this evening. This event had no impact on the health and/or safety of the Public. The USNRC Senior Resident Inspector has been notified. |
| Where | |
|---|---|
| Pilgrim Massachusetts (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+1.52 h0.0633 days <br />0.00905 weeks <br />0.00208 months <br />) | |
| Opened: | David Noyes 20:12 Oct 31, 2012 |
| NRC Officer: | Charles Teal |
| Last Updated: | Oct 31, 2012 |
| 48466 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |