ENS 51187
ENS Event | |
|---|---|
13:00 Jun 28, 2015 | |
| Title | Control Room Environmental Boundary Door Found Unlatched |
| Event Description | During Security checks of Control Room doors, a boundary door was found not latched. This door is capable of being manually closed and latched. The door was in this condition for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> and 25 minutes. The door is currently closed and latched. This is being reported as it could have prevented the fulfillment of a safety function to mitigate the consequences of an accident per 10 CFR 50.72(b)(3)(v)(D).
The NRC Resident Inspector has been notified. A condition report has been written and the door is posted to require manual checks to ensure it is latched until the door closing mechanism is repaired.
Event Report number 51187 describes a condition at Millstone Power Station Unit 2 (MPS2) in which a control room environmental boundary door was found unlatched. This was reported in accordance with 10CFR 50.72(b)(3)(v)(D) as a condition that could have prevented the fulfillment of a safety function to mitigate the consequences of an accident. Upon further review, MPS2 has concluded that there was no loss of safety function, because even with the control room boundary door unlatched, the control room emergency ventilation system would have been able to perform its safety function during accident conditions. The MPS2 control room is pressure neutral and the hydraulic door closure mechanism was verified adequate to ensure the door would close and remain closed during accident conditions (even though it was not latching). Therefore, this condition is not reportable and NRC Event 51187 is being retracted. The basis for this conclusion will be provided to the NRC Resident Inspector. Notified the R1DO (Cahill). |
| Where | |
|---|---|
Millstone  Connecticut (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+-1.6 h-0.0667 days <br />-0.00952 weeks <br />-0.00219 months <br />) | |
| Opened: | Michael Watson 11:24 Jun 28, 2015 |
| NRC Officer: | Daniel Mills |
| Last Updated: | Jul 8, 2015 |
| 51187 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |