ENS 48053
ENS Event | |
|---|---|
01:46 Jun 28, 2012 | |
| Title | Manual Reactor Trip Due to 100% Load Reject |
| Event Description | Unit 2 Manual Reactor Trip was actuated due to indications of a 100% Load Rejection. The cause of the Load Rejection is not known at this time. All Control Rods are fully inserted. The RCS is being cooled by forced flow (reactor coolant pumps). Secondary heat sink is being provided by the condenser steam dumps utilizing the main feedwater system. The auxiliary feedwater system actuated based on low steam generator level, but has since been secured. There were no unexpected (inconsistent with nature of trip) pressure or level transients. Off site power remains available. No release occurred nor is ongoing. Emergency Core Cooling Systems did not actuate. No unexpected isolations occurred. Emergency Plan entry was not required.
The plant is stable at normal temperature and pressure. The electrical system is in a normal offsite power alignment. The Unit 2 Reactor Trip had no effect on Unit 1 which continues to operate at 100% power. The licensee has notified the NRC Resident Inspector.
On June 27, 2012 at 2046 CDT, a Unit 2 Manual Reactor Trip was initiated in anticipation of an automatic turbine trip due to operators noticing the turbine governor valves closing and turbine load reduction. It was originally reported that the cause was not known. This notification is updated to provide information to the cause of the load reduction. Troubleshooting has shown that the reduction of turbine load was due to a turbine speed channel card failing in the turbine control system. The card failure resulted in sending the auxiliary governor in the turbine control system an incorrect indicated overspeed condition and throttling the turbine governor valves to reduce the turbine speed. There was no actual turbine overspeed condition. The auxiliary governor is not part of the reactor protection system. No reactor protection setpoints were exceeded. All other plant systems functioned as required, including the Reactor Protection System. All control rods fully inserted into the core due to the manual reactor trip. There was no Emergency Core Cooling System actuation. No Emergency Diesel Generators were started and power continued to be supplied from off site. The reactor coolant system had forced circulation and the condenser steam dumps were used for decay heat removal from the steam generators. The licensee has notified the NRC Resident Inspector. Notified R3DO (Daley). |
| Where | |
|---|---|
Point Beach  Wisconsin (NRC Region 3) | |
| 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:+-0.67 h-0.0279 days <br />-0.00399 weeks <br />-9.17766e-4 months <br />) | |
| Opened: | Russ Parker 01:06 Jun 28, 2012 |
| NRC Officer: | John Shoemaker |
| Last Updated: | Jul 6, 2012 |
| 48053 - NRC Website | |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | Yes, Manual Scram |
| Before | Power Operation (100 %) |
| After | Hot Standby (0 %) |
Point Beach with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
WEEKMONTHYEARENS 553902021-07-31T21:46:00031 July 2021 21:46:00
[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 Trip of Unit 1 ENS 537792018-12-05T06:00:0005 December 2018 06:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip on Loss of Main Condenser Vacuum ENS 515702015-11-29T01:12:00029 November 2015 01:12:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Generator Lockout After Voltage Regulator Malfunction ENS 515062015-10-29T08:48:00029 October 2015 08:48:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Actuation of the Auxiliary Feedwater System Due to Main Transformer Lockout ENS 506492014-12-03T02:50:0003 December 2014 02:50:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to Failure of Condensate Pump ENS 487222013-02-06T17:43:0006 February 2013 17:43:00 10 CFR 50.72(a)(1)(i), Emergency Class Declaration, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unusual Event - Loss of Offsite Power to Essential Buses for Greater than 15 Minutes ENS 481892012-08-15T01:31:00015 August 2012 01:31:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unit 1 Manually Tripped in Anticipation of an Automatic Turbine Trip ENS 480532012-06-28T01:46:00028 June 2012 01:46:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to 100% Load Reject ENS 474782011-11-27T08:38:00027 November 2011 08:38:00 10 CFR 50.72(a)(1)(i), Emergency Class Declaration, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unusual Event Due to a Loss of Offsite Power During Switching Operations ENS 469572011-06-14T00:24:00014 June 2011 00:24:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Trip During Startup Physics Testing ENS 464822010-12-15T07:48:00015 December 2010 07:48:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unit 2 Manual Reactor Trip During Startup ENS 461292010-07-27T01:01:00027 July 2010 01:01:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to Loss of Condenser Vacuum ENS 460802010-07-09T11:47:0009 July 2010 11:47:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to a Feedwater Regulating Valve Failure ENS 460322010-06-19T11:36:00019 June 2010 11:36:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to Generator Lockout ENS 434072007-06-05T20:17:0005 June 2007 20:17:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip After Feedwater Valve Failure ENS 421992005-12-13T09:39:00013 December 2005 09:39:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip Due to Loss of Condenser Vacuum ENS 407542004-05-15T16:54:00015 May 2004 16:54:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to Diver Entangled in Intake Crib 2021-07-31T21:46:00 | |