ENS 50801
ENS Event | |
|---|---|
08:50 Feb 10, 2015 | |
| Title | Voids Identified That Result in an Unanalyzed Condition |
| Event Description | On February 10, 2015, Prairie Island Unit 1 was shutdown in Mode 3 during a planned outage. Ultrasonic testing in support of Unit 1 Emergency Core Cooling System (ECCS) void verifications identified existing voids with calculated volumes in excess of the OPERABILITY limits specified by the procedure. This rendered both trains of Residual Heat Removal (RHR) systems inoperable requiring entry into Technical Specification 3.0.3 at 0250 [CST].
The station took prompt actions to vent the identified voids. The void at 1 RH-12 was vented to within acceptable limits allowing LCO 3.0.3 to be exited at 0538 on February 10. Venting at 1RH-11 is in progress. Voiding was identified at location 1-RH-11 with a calculated volume of 62.21 cubic inches with an OPERABILITY limit of 11.62 cubic inches. Voiding was identified at location 1-RH-12 with a calculated volume of 350 cubic inches with an OPERABILITY limit of 22.84 cubic inches. There was no impact to the health and safety of the public as Safety Injection was available and the time both trains of RHR were INOPERABLE was limited. This event is being reported as a unanalyzed condition that significantly degrades plant safety and a condition that could have prevented the fulfillment of a safety function (i.e., remove residual heat) under 10CFR50.72(b)(3)(ii) and 10CFR50.72(b)(3)(v). The licensee notified the NRC Resident Inspector.
Further analysis was performed on the two void locations, 1RH-11 and 1RH-12. Based on this additional analysis from AREVA, it was determined that the void located at 1RH-11 (RHR Train A) was operable. The calculations for past operability at inspection location 1RH-11 provides reasonable assurance that a void of 65 cubic inches will not generate forces that will fault any piping and supports. The void location at 1RH-12 (RHR Train B) was considered inoperable due to exceeding current procedural operability limits. The void located at 1RH-11 was determined to be nonconforming due to exceeding procedural design basis limits. Therefore, with RHR Train A determined to be operable, this event was not an 8-hour notification for an unanalyzed condition that significantly degrades plant safety, nor a condition that could have prevented the fulfillment of a safety function (i.e., remove residual heat) under 10CFR50.72(b)(3)(ii) and 10CFR50.72(b)(3)(v). The licensee has notified the NRC Resident Inspector. Notified the R3DO (Skokowski). |
| Where | |
|---|---|
Prairie Island  Minnesota (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat | |
| Time - Person (Reporting Time:+1.85 h0.0771 days <br />0.011 weeks <br />0.00253 months <br />) | |
| Opened: | Tom Holt 10:41 Feb 10, 2015 |
| NRC Officer: | Jeff Herrera |
| Last Updated: | Apr 11, 2015 |
| 50801 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Hot Standby (0 %) |
| After | Hot Standby (0 %) |
Prairie Island with 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
WEEKMONTHYEARENS 535462018-08-10T05:00:00010 August 2018 05:00:00
[Table view]10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 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 Emergency Diesel Generator Cooling Water Pumps Declared Inoperable ENS 526382017-03-20T21:39:00020 March 2017 21:39:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Historical Event Related to Past Operability ENS 518772016-04-21T20:50:00021 April 2016 20:50:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Missing Fire Barriers ENS 516422016-01-08T01:00:0008 January 2016 01:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition - Appendix R Credited Procedures Not in Place ENS 516162015-12-21T22:25:00021 December 2015 22:25:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Non-Compliant Fire Protection Manual Operator Actions ENS 514982015-10-26T12:03:00026 October 2015 12:03:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Associated with a High Energy Line Break ENS 509942015-04-19T22:45:00019 April 2015 22:45:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Non Compliance with 10 Cfr 50 App R ENS 508012015-02-10T08:50:00010 February 2015 08:50:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Voids Identified That Result in an Unanalyzed Condition ENS 505312014-10-13T19:25:00013 October 2014 19:25:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to a Missing Fire Barrier ENS 505232014-10-10T22:17:00010 October 2014 22:17:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Missing Fire Barrier ENS 504752014-09-19T18:53:00019 September 2014 18:53:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Missing Fire Barriers ENS 503622014-08-08T15:26:0008 August 2014 15:26:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Lack of Appropriate Fuse Protection ENS 496852013-12-31T15:33:00031 December 2013 15:33:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Removal of Multiple Steam Generator Lateral Support Shims and Bumpers ENS 493612013-09-19T17:20:00019 September 2013 17:20:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition No Documented Plan in Place to Receive Additional Fuel Oil During Maximum Probable Flood Condition ENS 491282013-06-17T21:15:00017 June 2013 21:15:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Potential Unanalyzed Condition - Carbon Dioxide Fire Suppression System Does Not Meet Design Requirements ENS 479492012-05-22T21:30:00022 May 2012 21:30:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Identified During a Fire Protection Review ENS 475222011-12-09T17:59:0009 December 2011 17:59:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition- Degraded Fire Barrier Between Fire Areas ENS 473212011-10-05T12:27:0005 October 2011 12:27:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Two Loops of Reactor Coolant System (Rcs) Were Declared Inoperable ENS 466992011-03-25T15:53:00025 March 2011 15:53:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Potential Unanalyzed Condition Due to Power Level Greater than Limit ENS 465082010-10-23T00:49:00023 October 2010 00:49:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition - Battery Chargers May Lockup During a Design Basis Event ENS 463182010-10-07T18:52:0007 October 2010 18:52:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Degraded Fire Barrier ENS 462612010-09-16T18:43:00016 September 2010 18:43:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition - Degraded Fire Barrier Identified ENS 458552010-04-19T03:25:00019 April 2010 03:25:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 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 Lco 3.0.3 Entry and Loss of Safety Function Due to Loss of Turbine Building High Energy Line Break Compensatory Measure ENS 455672009-12-14T18:00:00014 December 2009 18:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Related to Certain Fire Conditions ENS 449312009-03-23T22:00:00023 March 2009 22:00:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition for Postulated Missile Hazard That Could Disable Both Trains of Component Cooling ENS 447732009-01-14T17:30:00014 January 2009 17:30:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Manual Actions for Fire Not in Compliance ENS 443792008-07-31T18:45:00031 July 2008 18:45:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Postulated High-Energy Line Break That Could Disable Both Trains of Component Cooling ENS 435922007-08-24T16:30:00024 August 2007 16:30:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Fire Barrier Separation Criteria Not Met for Afwp Rooms ENS 434042007-06-04T21:00:0004 June 2007 21:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Identified Non Compliant Fire Protection Manual Operator Actions ENS 430102006-11-25T01:45:00025 November 2006 01:45:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition ENS 413772005-02-06T02:46:0006 February 2005 02:46:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 4160 Volt Relaying and Metering Single Failure Vulnerability 2018-08-10T05:00:00 | |