ENS 51087
ENS Event | |
|---|---|
14:02 May 22, 2015 | |
| Title | |
| Event Description | On Friday, May 22, 2015 at 1002 EDT, with the Reactor Mode Select Switch in the Start-Up position and the reactor at approximately 3 percent core thermal power, while returning to power from Refueling Outage Number 20, a manual reactor scram was inserted due to degrading main condenser vacuum. The cause of the degraded vacuum is currently under investigation.
Following the reactor scram, all rods were verified to be fully inserted and no Emergency Operating Procedure entry conditions existed. All plant systems responded as designed. Currently reactor pressure is being maintained at 400 psig with the Mechanical Hydraulic Control System (turbine by-pass valves). Reactor water level is being maintained in normal bands with the Condensate and Feedwater System. Off-site power is being supplied to the station by the Startup Transformer (normal power supply for shutdown operations). This event had no impact on the health and/or safety of the public. The NRC Resident Inspector is on-site and has been notified. The licensee has notified the Massachusetts Emergency Management Agency. The licensee will be issuing a press release.
The following was provided by the licensee as clarifying information to the first paragraph of the original event notification: As a conservative measure, the operating crew had previously started reducing power from 20 percent core thermal power when it was first noticed that main condenser vacuum was degrading. This was well before any low condenser vacuum alarms were received. During the shutdown, after already securing the main turbine, the operating crew established benchmark values for degrading condenser vacuum for a normal plant shutdown and for a manual reactor scram should vacuum continue to decline to preclude an automatic scram. The licensee notified the NRC Resident Inspector. Notified R1DO (Dwyer). |
| Where | |
|---|---|
| Pilgrim Massachusetts (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation | |
| Time - Person (Reporting Time:+-0.43 h-0.0179 days <br />-0.00256 weeks <br />-5.89014e-4 months <br />) | |
| Opened: | Mike Mcdonnell 13:36 May 22, 2015 |
| NRC Officer: | Steven Vitto |
| Last Updated: | May 24, 2015 |
| 51087 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | Yes, Manual Scram |
| Before | Startup (3 %) |
| After | Hot Shutdown (0 %) |
Pilgrim with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation | |
WEEKMONTHYEARENS 540712019-05-18T03:03:00018 May 2019 03:03:00
[Table view]10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram Due to Degrading Condenser Vacuum ENS 536482018-10-05T04:00:0005 October 2018 04:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram Due to Low Reactor Water Level ENS 531472018-01-04T19:10:0004 January 2018 19:10:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram Due to Partial Loss of Offsite Power During Winter Storm ENS 522232016-09-06T12:27:0006 September 2016 12:27:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram Due to High Reactor Water Level ENS 513382015-08-22T20:28:00022 August 2015 20:28:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Scram Due to a Single Msiv Closure ENS 510872015-05-22T14:02:00022 May 2015 14:02:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram Due to Loss of Condenser Vacuum ENS 507692015-01-27T09:02:00027 January 2015 09:02:00 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 Automatic Reactor Scram on Turbine Trip Due to Loss of Offsite Power ENS 492962013-08-22T11:55:00022 August 2013 11:55:00 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 Reactor Protection Actuation (Scram) ENS 487362013-02-09T03:00:0009 February 2013 03:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(a)(1)(i), Emergency Class Declaration Unusual Event Declared Due to Loss of Offsite Power ENS 486642013-01-10T20:34:00010 January 2013 20:34:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Reactor Protection Actuation (Scram) - Recirculation Pump Trip ENS 479452012-05-22T17:11:00022 May 2012 17:11:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram Due to Degrading Condenser Vacuum ENS 468372011-05-10T17:15:00010 May 2011 17:15:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Reactor Protection System Actuation During Start-Up ENS 447352008-12-19T23:31:00019 December 2008 23:31:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram Due to Load Reject ENS 434792007-07-10T23:54:00010 July 2007 23:54:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Main Turbine Trip Causing a Reactor Scram ENS 424142006-03-13T23:08:00013 March 2006 23:08:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram After Offgas System Failure 2019-05-18T03:03:00 | |