ENS 50714
ENS Event | |
|---|---|
14:25 Jan 2, 2015 | |
| Title | High Head Safety Injection Inoperable Due To Voids Identified In Piping |
| Event Description | At 0925 [EST] on 1/2/2015, Engineering personnel identified a gas void in each of two Unit 4 cold leg High Head Safety Injection (HHSI) discharge lines which exceeded procedural gas accumulation acceptance criteria. This condition rendered the cold leg HHSI flow path inoperable and required entry into Technical Specification 3.0.3. The voids were vented and Technical Specification (TS) 3.0.3 was exited at 1032.
The testing for gas voids conducted on 1/2/2015 was a follow-up to a gas void found in one Unit 4 HHSI line on 12/26/2014. On 12/26/14, TS 3.0.3 was entered at 1020 and exited at 1048 after the gas void was vented. After further review, the 12/26/2014 event was also reportable in accordance with 10 CFR 50.72(b)(3)(v)(D). Engineering evaluation will be performed for both events to determine the specific impact of the gas voids on HHSI system function. Cause evaluation is being conducted to determine the source of the gas and any needed corrective actions. Unit 3 was verified to not have this voiding issue. The licensee notified the NRC Resident Inspector.
On 1/2/2015 at 1645 [EST], Event Notification 50714 reported to the NRCOC [Nuclear Regulatory Commission Operations Center] gas voids detected on 12/26/2014 and 1/2/2015 in Unit 4 cold leg High Head Safety Injection (HHSI) piping which exceeded procedural gas accumulation acceptance criteria. Subsequent analysis has determined that if a HHSI pump started with the measured gas voids present, the resulting system conditions would not have impacted the integrity of the Unit 4 HHSI discharge flow path to the reactor coolant system (RCS) and therefore its safety related function would not be impaired. The Unit 4 HHSI system discharge flow path to the RCS had been operable with the voids present, Technical Specification (TS) requirements were met, and entry into TS 3.0.3 was not required. The HHSI system remained capable of fulfilling the safety function to mitigate the consequences of an accident on Unit 4. Therefore, the immediate notification to the NRCOC on 1/2/2015 at 1645 in accordance with 10 CFR 50.72(b)(3)(v)(D) is hereby retracted. The NRC Resident Inspector has been informed. Notified R2DO (Shaeffer). |
| Where | |
|---|---|
Turkey Point  Florida (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:+2.33 h0.0971 days <br />0.0139 weeks <br />0.00319 months <br />) | |
| Opened: | Dirk Drinkard 16:45 Jan 2, 2015 |
| NRC Officer: | Vince Klco |
| Last Updated: | Mar 11, 2015 |
| 50714 - NRC Website
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Unit 4 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |