ENS 43809
ENS Event | |
|---|---|
08:30 Nov 28, 2007 | |
| Title | Hpci Inoperable Due to Level Switch Failure |
| Event Description | On 11/28/2007 at 0230 CST, Browns Ferry Unit 1 received a 'HPCI PUMP SUCT HDR LEVEL LOW' alarm and HPCI automatically transferred its suction from the Condensate Storage Tank (CST) to the Suppression Pool. With the HPCI suction not aligned to its normal source, the HPCI system was declared inoperable. At 0710 CST, trouble shooting identified a level switch malfunction. This switch was removed from service allowing HPCl to be returned to the normal Standby Readiness configuration. The System was declared Operable at 0710 when the system was aligned back to normal suction source.
This event is reportable under 10CFR 50.72(b)(3)(v)(B) 'any 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: Remove Residual Heat' and 10CFR 50.72(b)(3)(v)(D) 'any 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: mitigate the consequences of an accident.' This event also requires a 60 day written report in accordance with 10CFR 50.73(a)(2)(v)(B) and 10CFR 50.73(a)(2)(v)(D). The licensee notified the NRC Resident Inspector.
ENS Event Number 43809, made on 11/28/2007, is being retracted. NRC Notification 43809 was conservatively made to ensure that the eight-hour non-emergency reporting requirements of 10 CFR 50.72 were met pending the evaluation of an atypical system alignment with the High Pressure Coolant Injection (HPCI) [system]. An evaluation has been performed in response to this event. The evaluation concluded that the HPCI system was capable of performing its intended safety function in this atypical configuration. As such, the circumstances discussed in the report did not result in any condition that could have prevented the fulfillment of the safety function of structures or systems needed to mitigate the consequences of an accident. Thus there would have no impact on nuclear safety. Therefore, this event is not reportable under 10 CFR 50.72(b)(3)(v)(B) or 10 CFR 50.72(b)(3)(v)(D). TVA's evaluation of this event is documented in the corrective action program. The licensee has notified the NRC Resident Inspector. Notified R2DO (Desai). |
| Where | |
|---|---|
Browns Ferry  Alabama (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat | |
| Time - Person (Reporting Time:+2.87 h0.12 days <br />0.0171 weeks <br />0.00393 months <br />) | |
| Opened: | Donald Smith 11:22 Nov 28, 2007 |
| NRC Officer: | Mark Abramovitz |
| Last Updated: | Jan 25, 2008 |
| 43809 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |