ENS 45815
ENS Event | |
|---|---|
02:50 Apr 6, 2010 | |
| Title | Loss of Safety Function to Control the Release of Radioactive Material |
| Event Description | At 2145 [EDT] hours on April 5, 2010, a loss of electrical power to the Division 1 Loss of Coolant Accident (LOCA) initiation logic occurred. Control room annunciators for 'Residual Heat Removal (RHR) Out of Service', 'Reactor Core Isolation Cooling (RCIC) Out of Service', and 'RCIC/RHR D2 to D1 00 File Power Loss' were received. At 2250 hours0.026 days <br />0.625 hours <br />0.00372 weeks <br />8.56125e-4 months <br />, the Control Room staff determined a loss of isolation function existed. The operators entered Technical Specification (TS) action statements for Emergency Core Cooling System Instrumentation (TS 3.3.5.1), RCIC Instrumentation (TS 3.3.5.2), and Primary Containment and Drywell Isolation Instrumentation (TS 3.3.6.1). The power loss was caused by a blown fuse which occurred during surveillance testing. The surveillance test was suspended and plant personnel commenced troubleshooting and investigation efforts. A recovery plan is being developed to back out of the surveillance test and replace the fuse to re-energize the logic, while ensuring the plant does not experience an undesirable actuation of the logic.
The power loss caused five containment isolation valves to lose automatic isolation function. These valves have no associated inboard automatic isolation valve powered by Division 2. As a result of the power loss, the valves cannot automatically close on demand to isolate and therefore cannot perform their automatic function to isolate the containment. This event is being reported in accordance with 10 CFR 50.72(b)(3)(v)(C) as an event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to control the release of radioactive material. The NRC Resident Inspectors have been notified. The licensee entered a 12-hour shutdown action statement for the loss of containment isolation function as a result of the power failure.
On April 6, 2010, at 0611 hours0.00707 days <br />0.17 hours <br />0.00101 weeks <br />2.324855e-4 months <br />, notification was made to NRC Operations Center of an event that at the time of discovery, could have prevented the fulfillment of the safety function of structures or systems that are needed to control the release of radioactive material [10 CFR 50.72(b)(3)(v)(c)]. A blown fuse during surveillance testing caused a loss of electrical power to the Division 1 Loss of Coolant Accident initiation logic. The power loss caused five containment isolation valves to lose their automatic isolation function. These valves have no associated inboard automatic isolation valve powered by Division 2. As a result of the power loss, the valves could not automatically close on demand and therefore, could not perform their automatic function to isolate containment. Following further evaluation, it was determined that a loss of safety function of structures or systems that are needed to control the release of radioactive material did not occur. Based on review of valve leak rate test history and compliance with 10 CFR 50, Appendix A, General Design Criteria, the penetrations and Containment were capable of performing their intended design function. The associated inboard valves and/or water seals were capable of automatically isolating containment. Additionally, all required Technical Specifications Limiting Conditions for Operation were complied with for the identified issue, and therefore, no operation or condition prohibited by the plant's Technical Specifications existed. Since the event or condition reported in Event Notification 45815 would not have prevented the fulfillment of the safety function needed to control the release of radioactive material, this event or condition is not reportable and the notification is retracted. Additionally, based on not meeting any 10 CFR 50.73 reporting criteria, no Licensee Event Report is required. The evaluation (i.e., Reportability Determination) for this event or condition is documented in Condition Report 10-74904. The NRC Resident Inspector has been notified. Notified the R3DO (Pelke). |
| Where | |
|---|---|
Perry  Ohio (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | |
| Time - Person (Reporting Time:+3.35 h0.14 days <br />0.0199 weeks <br />0.00459 months <br />) | |
| Opened: | Douglas Shorter 06:11 Apr 6, 2010 |
| NRC Officer: | Howie Crouch |
| Last Updated: | Jun 4, 2010 |
| 45815 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |