ENS 48923
ENS Event | |
|---|---|
02:17 Apr 15, 2013 | |
| Title | Specified System Actuations While Shutting Down |
| Event Description | On Sunday, April 14, 2013 at 2217 hours0.0257 days <br />0.616 hours <br />0.00367 weeks <br />8.435685e-4 months <br />, with the Pilgrim Nuclear Power Station (PNPS) Reactor Mode Select Switch (RMSS) in Start-up, the turbine generator previously removed from service, and the reactor sub-critical on Intermediate Range Monitors Range 2 and lowering, a manual reactor scram was inserted due to reactor pressure lowering beyond established control bands. At the time of the manual reactor scram PNPS was conducting a planned reactor shutdown to commence refueling outage (RFO) -19. All control rods fully inserted and Primary Containment Isolation System Group II (Reactor Building) and Group VI (Reactor Water Cleanup System) actuations occurred as designed due to the expected reactor water level shrink associated with the scram signal. All plant systems responded as designed. Off-site power was unaffected and was supplied by the start-up transformer (normal power supply for refuel and reactor shutdown operations).
The Main Steam Isolation Valves (MSIV) were manually closed to terminate the reactor pressure reduction and the High Pressure Coolant Injection (HPCI) system was manually started in the reactor pressure control mode. The Reactor Protection System (RPS) was reset as were the reactor building and reactor water clean-up system isolation signals. Currently, the plant cooldown is continuing with the HPCI system in pressure control and reactor water level being maintained within normal bands with the condensate and feedwater system. The cause of the lowering reactor pressure has not been determined and remains under review. This event had no impact on the health and/or safety of the public. This 8-hour notification is being made in accordance with 10 CFR 50.72 (b)(3)(iv)(A). The NRC Senior Resident Inspector has been notified. The licensee will also be notifying state authorities. |
| Where | |
|---|---|
| Pilgrim Massachusetts (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| Time - Person (Reporting Time:+-0.27 h-0.0113 days <br />-0.00161 weeks <br />-3.69846e-4 months <br />) | |
| Opened: | John Whalley 02:01 Apr 15, 2013 |
| NRC Officer: | Bill Huffman |
| Last Updated: | Apr 15, 2013 |
| 48923 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | Yes, Manual Scram |
| Before | Startup (0 %) |
| After | Hot Shutdown (0 %) |