ENS 50356
ENS Event | |
|---|---|
06:38 Aug 12, 2014 | |
| Title | Hpci Potential Inoperability Discovered During Post Maintenance Testing |
| Event Description | At 0238 hours0.00275 days <br />0.0661 hours <br />3.935185e-4 weeks <br />9.0559e-5 months <br /> [EDT] on Tuesday, August 12, 2014, with Pilgrim Station at 100 percent power in the Run Mode with reactor coolant pressure at approximately 1025 psig and the High Pressure Coolant Injection (HPCI) System previously removed from service for maintenance, a condition with the potential to impact the operability of the HPCI System was discovered. The HPCI System was being operated in accordance with plant procedures to complete post maintenance test requirements. Upon HPCI initiation, the indicated flow on HPCI Flow Indicator FI-2340-1-1 was 0 Gallons Per Minute (GPM) with the flow controller in the manual mode. The indicated flow on HPCI Flow Indicator Fl-2340-1-1 remained at 0 GPM throughout the duration of the surveillance. Alternate flow indication indicated the expected HPCI flow rate. The flow controller in manual was capable of controlling at the demanded HPCI turbine speed. The HPCI turbine speed was manually varied with a corresponding change in the HPCI flow computer point reading. Activities to restore the flow indicator capability are in progress.
The plant is in a safe condition and plant personnel are investigating the cause of the flow indicator issue. The NRC Resident Inspector has been informed of this notification. This notification is being made in accordance with 10 CFR 50.72(b)(3)(v)(B) and 10 CFR 50.72(b)(3)(v)(D). The licensee will be notifying the state.
Subsequent investigation determined that HPCI Flow Instrument SQRT-2340-10 output signal was 0 mA and did not change in response to the actual HPCI flow rate. With the SQRT-2340-10 output signal at 0 mA, the HPCI Flow controller would demand maximum HPCI injection flow in the AUTOMATIC control mode. Circuitry within the control system limits the maximum HPCI flow to 5250 GPM at a turbine speed of 4165 RPM. Engineering analysis has concluded that the HPCI pump operating limits (net positive suction head and low pressure suction trip) would not be exceeded in a maximum HPCI flow state. Therefore, the HPCI System was operable and capable of performing its residual heat removal and accident mitigation functions. Therefore, the initial 50.72(b)(3)(v)(B) and 10CFR50.72(b)(3)(v)(D) report is being retracted. The [NRC] Resident Inspector has been informed of this notification retraction. Notified the R1DO (Krohn). |
| Where | |
|---|---|
| Pilgrim Massachusetts (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+3.9 h0.163 days <br />0.0232 weeks <br />0.00534 months <br />) | |
| Opened: | John Whalley 10:32 Aug 12, 2014 |
| NRC Officer: | Mark Abramovitz |
| Last Updated: | Oct 3, 2014 |
| 50356 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |