ENS 51153
ENS Event | |
|---|---|
15:30 Jun 12, 2015 | |
| Title | |
| Event Description | On June 12, 2015 at 1030 CDT, the Browns Ferry Nuclear Plant Unit 3 High Pressure Coolant Injection (HPCI) system was declared inoperable due to the time to drain the Turbine Exhaust Drain Pot after running the system for periodic testing. The concern is that the turbine may be partially flooded after shutting down and a subsequent restart could cause a water hammer event, possibly damaging the system. This issue was previously analyzed by Engineering as acceptable, but the time to drain the pot after the latest test indicates more water in the exhaust than the maximum amount used in the analysis.
Technical Specification 3.5.1, ECCS Operating, Condition C, was entered as a result of the inoperable HPCI system. This constitutes an unplanned HPCI system inoperability and requires an 8-hour NRC notification in accordance with 10 CFR 50.72(b)(3)(v)(D) due to the failure of a single train system affecting accident mitigation, and a 60 day written report in accordance with 10 CFR 50.73(a)(2)(v) The NRC Resident Inspector has been notified. The Technical Specification Action statement allows 14 days to restore the HPCI system to operable status.
Browns Ferry Nuclear Plant is retracting the 8-hour NRC notification (EN# 51153) made on June 12, 2015 at 1030 CDT. The notification on June 12, 2015, reported a condition where the HPCI system was declared inoperable due to the time to drain the Turbine Exhaust Drain Pot after running the system for periodic testing. The concern was that the turbine may be partially flooded which could cause water hammer and damage the HPCI system. Subsequent evaluation concluded that the HPCI system under the identified flooded turbine conditions will not produce a transient that exceeds design values, therefore, HPCI system operability was maintained and no reportable condition existed during this time. The NRC Resident Inspector has been notified of this retraction. Notified R2DO (Shaeffer). |
| 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 | |
| Time - Person (Reporting Time:+1.8 h0.075 days <br />0.0107 weeks <br />0.00247 months <br />) | |
| Opened: | Mark Moebes 17:18 Jun 12, 2015 |
| NRC Officer: | Daniel Mills |
| Last Updated: | Sep 10, 2015 |
| 51153 - NRC Website
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Unit 3 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |