ENS 50600
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ENS Event | |
|---|---|
18:16 Nov 6, 2014 | |
| Title | Technical Specification Required Shutdown Due to Dropped Control Element Assembly |
| Event Description | On November 6, 2014 at 1116 Mountain Standard Time (MST), Control Element Assembly (CEA) 15 dropped fully into the core while all other CEAs remained fully withdrawn. Limiting Condition for Operation (LCO) 3.1.5 Condition A was entered for one CEA misaligned from its group which requires restoration of the CEA within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. An initial power reduction was performed upon receipt of the deviation in accordance with technical specifications. The CEA could not be aligned within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and LCO 3.1.5 Condition C was entered at 1316 MST which requires entry into Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. Power reduction continues as necessary to comply with technical specifications.
No major equipment was inoperable prior to the event that contributed to the event. No emergency classification was required per the Emergency Plan. No automatic essential safety feature actuations occurred and none were required. The Emergency Diesel Generators did not start and were not required. Safety related buses remain energized. The offsite power grid is stable. Other LCOs were entered as required by technical specifications. The licensee has notified the NRC Resident Inspector.
Efforts to repair the CEA control system and realign CEA 15 with the other CEAs in its regulating group were unsuccessful. Shutdown of Unit 2 was completed at 1636 [MST] in accordance with normal operating procedures to comply with the shutdown requirements of LCO 3.1.5 Condition C. Unit 2 is currently stable in Mode 3 with the reactor coolant system at normal operating temperature and pressure. All equipment responded as expected with the exception of steam generator # 2 economizer feedwater regulating valve which remained 3 percent open. The economizer feedwater isolation valves to both steam generators were manually closed to isolate the economizer feedwater flow paths. The event did not result in any challenges to fission product barriers and there were no adverse safety consequences as a result of this event. The NRC Resident Inspector has been informed of the Unit 2 shutdown. Notified R4DO (Miller) |
| Where | |
|---|---|
Palo Verde  Arizona (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | |
| LER: | 05000529/LER-2014-002 |
| Time - Person (Reporting Time:+0.1 h0.00417 days <br />5.952381e-4 weeks <br />1.3698e-4 months <br />) | |
| Opened: | Robert Warner 18:22 Nov 6, 2014 |
| NRC Officer: | Dong Park |
| Last Updated: | Nov 7, 2014 |
| 50600 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (20 %) |
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 | |
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