ENS 46475
ENS Event | |
|---|---|
18:10 Dec 13, 2010 | |
| Title | Technical Specification Required Shutdown Due to Not Meeting Rod Group Allignment Limits |
| Event Description | {{#Wiki_filter:On 12/13/10 at 1210 CST a Technical Specification (TS) required shutdown was initiated on Unit 2. TS Limiting Condition for Operation (LCO) 3.1.4, Rod Group Alignment Limits, was not met as a result of Surveillance Requirement (SR) 3.1.4.2 not being met. TS Action Condition (TSAC) 3.1.4.A was entered which requires the shutdown margin to be within the limits of the Core Operating Limits Report (COLR) or boration be initiated to restore shutdown margin to within the limits within one hour and that the reactor to be in MODE 3 within 6 hours. Shutdown margin has been verified to be within the limits specified in the COLR and a reactor shutdown has been initiated.
On 12/10/10 at 1350 [CST], during performance of Technical Specification surveillance procedure TS-06 Rod Exercise Test, rod control urgent and non-urgent failure alarms occurred while stepping Control Bank B rods out. These alarms were verified locally in the Unit 2 rod drive room. On 12/10/10 at 2212 [CST], the test recommenced and control bank B was stepped out one step as procedurally required with no alarms. When control bank B was subsequently stepped inward one step, both rod control urgent and non-urgent failure alarms were received. Both of the times that Control Bank B rods failed to move, the movable gripper coil power supply fuse blew for control rod F-6. On 12/12/10 at 2143 CST, the surveillance procedure for Control Banks A, C, and D and Shutdown Banks A and B were completed satisfactorily, however, the failure of the Control Bank B rods to step in correctly resulted in the inability to satisfy SR 3.1.4.2, and entry into TSAC 3.1.4.A being required. During continuation of the surveillance on 12/12/10, it was not recognized that troubleshooting and repairs could not be conducted satisfactorily prior to the expiration of the surveillance interval. Therefore, a TS-required shutdown in accordance was not initiated. The likely cause of the failure is a damaged cable in the movable gripper circuitry for control rod F�6. Troubleshooting is continuing and a repair plan has been developed. The NRC Senior Resident Inspector and Region III have been notified.
On 12/13/10 at 1210 CST, a Technical Specifications (TS) required shutdown was initiated on the Unit 2 reactor. TS Limiting Condition for Operation (LCO) 3.1.4 Rod Group Alignment Limits was not met due to exceeding the specified Frequency and Grace Period for Surveillance Requirement (SR) 3.1.4.2, which required a verification of the freedom of movement (trippability) of each control rod not fully inserted into the core. TS LCO 3.1.4 is not met, and TS Action Condition 3.1.4.A was entered which requires the shutdown margin to be within the limits of the Core Operating Limits Report or boration be initiated to restore shutdown margin to within the limits within one hour as well as requiring that the reactor to be in Mode 3 within 6 hours. Shutdown margin has been verified to be within the limits specified in the Core Operating Limits Report and a reactor shutdown has been initiated. On 12/10/10 at 1350 CST, during performance of TS Surveillance-6 (TS-6) Rod Exercise Test, Rod Control Urgent and Non-Urgent failure alarms occurred while stepping Control Bank B rods out. These alarms were verified locally in the Unit 2 rod drive room. On 12/10/10 at 2212 CST, TS-6 recommenced and Control Bank B was stepped out one step as procedurally required with no alarms. When control bank B was subsequently stepped inward one step, both Rod Control Urgent and Non-Urgent failure alarms were received again. Both of the times that the Control Bank B rods failed to move, the movable gripper coil power supply fuse blew for control rod F-6. On 12/12/10 at 2143 CST, TS-6 for control banks A, C, & D and Shutdown Banks A & B was completed satisfactorily. Troubleshooting is continuing and a repair plan has been developed. The NRC Resident Inspector has been notified. Notified R3DO (Kozak), IRD (Grant), NRR (Evans) }}[[Event description::Description::{{#Regex_clear:On 12/13/10 at 1210 CST a Technical Specification (TS) required shutdown was initiated on Unit 2. TS Limiting Condition for Operation (LCO) 3.1.4, Rod Group Alignment Limits, was not met as a result of Surveillance Requirement (SR) 3.1.4.2 not being met. TS Action Condition (TSAC) 3.1.4.A was entered which requires the shutdown margin to be within the limits of the Core Operating Limits Report (COLR) or boration be initiated to restore shutdown margin to within the limits within one hour and that the reactor to be in MODE 3 within 6 hours. Shutdown margin has been verified to be within the limits specified in the COLR and a reactor shutdown has been initiated. On 12/10/10 at 1350 [CST], during performance of Technical Specification surveillance procedure TS-06 Rod Exercise Test, rod control urgent and non-urgent failure alarms occurred while stepping Control Bank B rods out. These alarms were verified locally in the Unit 2 rod drive room. On 12/10/10 at 2212 [CST], the test recommenced and control bank B was stepped out one step as procedurally required with no alarms. When control bank B was subsequently stepped inward one step, both rod control urgent and non-urgent failure alarms were received. Both of the times that Control Bank B rods failed to move, the movable gripper coil power supply fuse blew for control rod F-6. On 12/12/10 at 2143 CST, the surveillance procedure for Control Banks A, C, and D and Shutdown Banks A and B were completed satisfactorily, however, the failure of the Control Bank B rods to step in correctly resulted in the inability to satisfy SR 3.1.4.2, and entry into TSAC 3.1.4.A being required. During continuation of the surveillance on 12/12/10, it was not recognized that troubleshooting and repairs could not be conducted satisfactorily prior to the expiration of the surveillance interval. Therefore, a TS-required shutdown in accordance was not initiated. The likely cause of the failure is a damaged cable in the movable gripper circuitry for control rod F�6. Troubleshooting is continuing and a repair plan has been developed. The NRC Senior Resident Inspector and Region III have been notified.
On 12/13/10 at 1210 CST, a Technical Specifications (TS) required shutdown was initiated on the Unit 2 reactor. TS Limiting Condition for Operation (LCO) 3.1.4 Rod Group Alignment Limits was not met due to exceeding the specified Frequency and Grace Period for Surveillance Requirement (SR) 3.1.4.2, which required a verification of the freedom of movement (trippability) of each control rod not fully inserted into the core. TS LCO 3.1.4 is not met, and TS Action Condition 3.1.4.A was entered which requires the shutdown margin to be within the limits of the Core Operating Limits Report or boration be initiated to restore shutdown margin to within the limits within one hour as well as requiring that the reactor to be in Mode 3 within 6 hours. Shutdown margin has been verified to be within the limits specified in the Core Operating Limits Report and a reactor shutdown has been initiated. On 12/10/10 at 1350 CST, during performance of TS Surveillance-6 (TS-6) Rod Exercise Test, Rod Control Urgent and Non-Urgent failure alarms occurred while stepping Control Bank B rods out. These alarms were verified locally in the Unit 2 rod drive room. On 12/10/10 at 2212 CST, TS-6 recommenced and Control Bank B was stepped out one step as procedurally required with no alarms. When control bank B was subsequently stepped inward one step, both Rod Control Urgent and Non-Urgent failure alarms were received again. Both of the times that the Control Bank B rods failed to move, the movable gripper coil power supply fuse blew for control rod F-6. On 12/12/10 at 2143 CST, TS-6 for control banks A, C, & D and Shutdown Banks A & B was completed satisfactorily. Troubleshooting is continuing and a repair plan has been developed. The NRC Resident Inspector has been notified. Notified R3DO (Kozak), IRD (Grant), NRR (Evans) }}| ]] |
| Where | |
|---|---|
Point Beach  Wisconsin (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | |
| Time - Person (Reporting Time:+-3.05 h-0.127 days <br />-0.0182 weeks <br />-0.00418 months <br />) | |
| Opened: | Karl Cossey 15:07 Dec 13, 2010 |
| NRC Officer: | Vince Klco |
| Last Updated: | Dec 15, 2010 |
| 46475 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 503962014-08-24T05:00:00024 August 2014 05:00:00
[Table view]10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Required Shutdown Due to Post Accident Monitoring Instrumentation Out of Service ENS 464752010-12-13T18:10:00013 December 2010 18:10:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Required Shutdown Due to Not Meeting Rod Group Allignment Limits ENS 439072008-01-15T20:15:00015 January 2008 20:15:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release, 10 CFR 50.72(a)(1)(i), Emergency Class Declaration, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Unusual Event - Loss of Offsite Power ENS 436492007-09-18T13:43:00018 September 2007 13:43:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Refueling Water Storage Tank Temperature Above Operating Limits ENS 434242007-06-14T23:19:00014 June 2007 23:19:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Tech Spec. Required Shutdown Due to 72 Hour Completion Time Not Met ENS 421092005-11-02T05:00:0002 November 2005 05:00:00 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 Due to Degradation of Containment Coatings ENS 414472005-02-27T17:58:00027 February 2005 17:58:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Required Shutdown Due to Loss of Dc Battery Chargers ENS 412122004-11-19T22:22:00019 November 2004 22:22:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Required Shutdown Due to a Steam Leak on an Instrument Isolation Valve Inside Containment ENS 406262004-03-30T18:15:00030 March 2004 18:15:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Safety Injection Accumulator Level Greater than Allowed by Technical Specification 2014-08-24T05:00:00 | |