ENS 49601
ENS Event | |
|---|---|
06:24 Dec 3, 2013 | |
| Title | Tech Spec Required Shutdown Due to Dropped Control Element Assembly |
| Event Description | The following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time a follow-up notification will be made via the ENS or under the reporting requirements of 10 CFR 50.73.
All times described are approximate Mountain Standard Time. At 2324 on December 2, 2013, Palo Verde Nuclear Generating Station (PVNGS) Unit 3 commenced a reactor shutdown required by Technical Specification (TS) 3.1.5, Control Element Assembly (CEA) Alignment. TS Limiting Condition for Operation (LCO) 3.1.5, requires 'All full strength CEAs shall be OPERABLE, and all full strength and part strength CEAs shall be aligned to within 6.6 inches (indicated position) of all other CEAs in their respective groups.' Regulating CEA number 69 dropped to the fully inserted position at 1830 on December 2, 2013, when the circuit breaker for CEA 69 tripped open. The other 88 CEAs in the reactor were unaffected and remained fully withdrawn. Unit 3 entered LCO 3.1.5 Condition A for one misaligned CEA and reduced power to 78% within one hour in accordance with Required Action A.1. The CEA was unable to be restored to its required position within two hours in accordance with Required Action A.2 to restore CEA alignment. At 2030, Unit 3 entered Condition C of LCO 3.1.5 because of the inability to restore CEA alignment. Condition C requires the unit to be in Mode 3 in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. At 0033 on December 3, 2013 the Power Switch Assembly was replaced and tested satisfactorily. The shutdown was terminated at this time while at approximately 48% power. At 0039, Unit 3 began to withdraw CEA 69. CEA 69 was realigned with its group at 0143 and LCO 3.1.5 conditions A and C were exited. The event did not result in the unplanned release of radioactivity to the environment and did not adversely affect the safe operation of the plant or health and safety of the public. The NRC Resident Inspector has been notified. |
| Where | |
|---|---|
Palo Verde  Arizona (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | |
| Time - Person (Reporting Time:+-2.32 h-0.0967 days <br />-0.0138 weeks <br />-0.00318 months <br />) | |
| Opened: | David Kelsey 04:05 Dec 3, 2013 |
| NRC Officer: | Daniel Mills |
| Last Updated: | Dec 3, 2013 |
| 49601 - NRC Website | |
Unit 3 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (78 %) |
| After | Power Operation (48 %) |
WEEKMONTHYEARENS 506002014-11-06T18:16:0006 November 2014 18:16:00
[Table view]10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Required Shutdown Due to Dropped Control Element Assembly ENS 496012013-12-03T06:24:0003 December 2013 06:24:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Tech Spec Required Shutdown Due to Dropped Control Element Assembly ENS 442742008-06-06T06:56:0006 June 2008 06:56:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Tech Spec Required Shutdown Due to Leak in Safety Injection Tank Vent Line ENS 438042007-11-24T05:26:00024 November 2007 05:26:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Required Plant Shutdown Due to Inoperable Load Sequencer ENS 437362007-10-22T10:11:00022 October 2007 10:11:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Shutdown Due to Inoperable Steam Driven Auxiliary Feedwater Pump ENS 431732007-02-19T21:57:00019 February 2007 21:57:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Unit 2 Performed a Ts Required Shutdown ENS 428472006-09-19T08:05:00019 September 2006 08:05:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Pressurizer Heater Capacity Less than Tech Spec Limit ENS 424872006-04-10T19:33:00010 April 2006 19:33:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Unit 2 Entered a Ts Required Shutdown Due to Inoperable Auxiliary Feedwater Pumps ENS 420502005-10-11T23:02:00011 October 2005 23:02:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Tech Spec Required Shutdown of Both Unit 2 and 3 ENS 419392005-08-22T23:05:00022 August 2005 23:05:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Shutdown Due to Core Protection Calculator System (Cpcs) Software Not Consistent with System Design Requirements. ENS 419132005-08-12T07:19:00012 August 2005 07:19:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Plant Entered Lco Action Statement 3.8.1 to Be in Mode 5 Due to Unit 1 "B" Diesel Gen. Being Declared Inoperable ENS 415022005-03-18T22:00:00018 March 2005 22:00:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Required Shutdown Due to Inoperable Diesel Generator ENS 413892005-02-09T08:04:0009 February 2005 08:04:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specifications Required Shutdown Due to Loss of Normal and Alternate Power to Safety Bus ENS 405032004-02-03T22:35:0003 February 2004 22:35:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown, 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Technical Specification Required Shutdown Due to Rcs Pressure Boundary Leakage 2014-11-06T18:16:00 | |