ENS Event | |
|---|---|
19:26 May 26, 2010 | |
| Title | Automatic Reactor Scram While Increasing Power |
| Event Description | At 1526 on 5/26/2010, while operators were increasing power with reactor recirculation flow, an RPS (Reactor Protection System) actuation occurred in both channels and all control rods inserted. RPV (Reactor Pressure Vessel) level decreased to 114.5 inches (Low level setpoint is less than 127 inches). Following the scram, the PCIS (Primary Containment Isolation System) groups 2, 3, 4 and 5 received actuation signals and all open valves isolated. Both trains of standby gas treatment system actuated.
Plant actions taken included entering procedures OT-3100, Reactor Scram on RPS Actuation and EOP-1, RPV Control on Low Level Signal. The EOP-1 was exited per shift manager direction because of no emergency. The operators stabilized the plant and reset both RPS and PCIS. An investigation into the cause of the scram is continuing. Electrical power is being supplied from offsite sources through the startup transformers. The licensee notified the NRC Resident Inspector. |
| Where | |
|---|---|
| Vermont Yankee File:NorthStar Vermont Yankee icon.png Vermont (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| Time - Person (Reporting Time:+-2.02 h-0.0842 days <br />-0.012 weeks <br />-0.00277 months <br />) | |
| Opened: | Andrew Wisniewski 17:25 May 26, 2010 |
| NRC Officer: | Vince Klco |
| Last Updated: | May 26, 2010 |
| 45957 - NRC Website
Loading map... | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | A |
| Before | Power Operation (72 %) |
| After | Hot Shutdown (0 %) |
Vermont YankeeFile:NorthStar Vermont Yankee icon.png with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
WEEKMONTHYEARENS 459572010-05-26T19:26:00026 May 2010 19:26:00
[Table view]10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram While Increasing Power ENS 436102007-08-30T19:13:00030 August 2007 19:13:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram on Turbine Stop Valve Closure ENS 418682005-07-25T04:00:00025 July 2005 04:00:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release, 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Automatic Reactor Trip Caused by Failure in Switchyard 2010-05-26T19:26:00 | |
