ENS 45872
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ENS Event | |
|---|---|
05:00 Apr 26, 2010 | |
| Title | Unit 1 Experienced an Automatic Reactor Trip During an Ni Calibration |
| Event Description | This is a 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> Non-Emergency 10CFR 50.72(b)(2)(iv)(B) notification due to an Automatic Reactor Protection System (RPS) actuation (scram). At 2126 hours0.0246 days <br />0.591 hours <br />0.00352 weeks <br />8.08943e-4 months <br /> [CDT] on April 25, 2010, Unit 1 Reactor automatically tripped due to 2 of 4 Reactor Protection System (RPS) Channels tripped. At the time of the trip, reactor power, as indicated by heat balance, was ~20%, while excore Nuclear Instrumentation (NI) indicated ~30%. The RPS high reactor power trip setpoint was 50% power. An NI calibration initiated an automatic withdrawal command to the control rod drive system. The rod withdrawal, resulted in one RPS channel tripping on high reactor power and another RPS channel tripping on high reactor coolant system pressure. All control rods fully inserted into the core and no safety systems, other than RPS, actuated. Emergency feedwater did not actuate and was not needed. No primary safety valves lifted. Seven secondary safety valves lifted and subsequently reseated. The plant is currently stable in Mode 3.
The NRC resident has been notified. The licensee also informed the State of Arkansas and does not plan a press release. The Unit 1 reactor trip was uncomplicated. Current means of decay heat removal is normal feedwater to the Steam Generators with steam discharge to the Main Condenser through Main Steam Bypass. The Main Generator was online at the time of the trip and the plant is currently in a normal post trip electrical line up. There is no indication of primary-secondary tube leakage. All systems functioned as required. |
| Where | |
|---|---|
Arkansas Nuclear  Arkansas (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation | |
| Time - Person (Reporting Time:+-3.42 h-0.143 days <br />-0.0204 weeks <br />-0.00468 months <br />) | |
| Opened: | Phil Harris 01:35 Apr 26, 2010 |
| NRC Officer: | Steve Sandin |
| Last Updated: | Apr 26, 2010 |
| 45872 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | A/R |
| Before | Power Operation (20 %) |
| After | Hot Standby (0 %) |
WEEKMONTHYEARENS 563512023-02-14T17:03:00014 February 2023 17:03:00
[Table view]10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Trip Due to Two Reactor Coolant Pumps Tripping ENS 556142021-11-29T20:58:00029 November 2021 20:58:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip ENS 551382021-03-14T19:15:00014 March 2021 19:15:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Trip Due to Loss Bus Voltage ENS 550282020-12-10T22:08:00010 December 2020 22:08:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Due to Low Steam Generator Water Level ENS 540912019-05-26T10:12:00026 May 2019 10:12:00 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 a Reactor Coolant Pump Trip on Ground Fault ENS 537932018-12-18T06:00:00018 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 Automatic Reactor Trip - Loss of Non-Vital Bus ENS 534592018-06-16T05:00:00016 June 2018 05:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip During Startup ENS 534042018-05-16T22:50:00016 May 2018 22:50:00 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 Loss of Main Feedwater Pump ENS 527102017-04-26T15:04:00026 April 2017 15:04:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unit 1 Automatic Reactor Scram Due to Partial Loss of Offsite Power ENS 516072015-12-15T11:44:00015 December 2015 11:44:00 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 Manual Reactor Trip Due to Loss of Feed to One Steam Generator ENS 500632014-04-28T01:12:00028 April 2014 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 an Auxiliary Trip on Core Protection Calculator ENS 499952014-04-03T18:01:0003 April 2014 18:01:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip ENS 496182013-12-09T14:00:0009 December 2013 14:00:00 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(a)(1)(i), Emergency Class Declaration, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unusual Event Declared Due to Unit 2 Auxiliary Transformer Explosion ENS 488692013-03-31T15:33:00031 March 2013 15:33:00 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(a)(1)(i), Emergency Class Declaration, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Notification of Unusual Event Declared Due to a Breaker Explosion in the Protected Area ENS 481692012-08-08T13:23:0008 August 2012 13:23:00 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 High Reactor Coolant System Pressurizer Pressure ENS 458722010-04-26T05:00:00026 April 2010 05:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Unit 1 Experienced an Automatic Reactor Trip During an Ni Calibration ENS 458542010-04-18T18:57:00018 April 2010 18:57:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip During Reactor Startup ENS 455492009-12-08T14:42:0008 December 2009 14:42:00 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 Low Steam Generator Level Caused by Loss of Main Feed Water Pump ENS 449062009-03-14T02:51:00014 March 2009 02:51:00 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 Feedwater Regulating Valve Failure Leads to Manual Reactor Trip ENS 448372009-02-07T16:59:0007 February 2009 16:59:00 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 a Fire Onsite ENS 448312009-02-05T21:24:0005 February 2009 21:24:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Unit 1 Manually Tripped Due to Control Rod Drive Motor High Temperatures ENS 447362008-12-20T18:12:00020 December 2008 18:12:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip When Control Rod Bank Inserted Without Operator Action ENS 447162008-12-12T14:55:00012 December 2008 14:55:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Unit 1 Was Manually Tripped from 32% Power Due to an Abnormal Rod Pattern ENS 422292005-12-26T16:47:00026 December 2005 16:47:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Following Turbine Trip ENS 401192003-08-29T19:28:00029 August 2003 19:28:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip on High Rcs Pressure 2023-02-14T17:03:00 | |
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