ENS 43375
ENS Event | |
|---|---|
07:12 May 19, 2007 | |
| Title | |
| Event Description | On the evening of 5/10/2007, Cooper began a scheduled down power to accomplish required preventive and corrective maintenance, including replacement of directional control valves on three control rod drive (CRD) hydraulic control units (HCU). HCU 26-27 was hydraulically isolated for maintenance. The plant was in a single recirculation loop configuration to perform corrective maintenance on 'A' Recirculation Motor Generator. A single reactor feed pump was in operation for corrective maintenance to the 'A' Reactor Feed Pump lube oil system.
At approximately 0025 CDT on 5/19/2007 reports from the field indicated that a small water leak had developed from the body to bonnet seal of CRD-V-122 for HCU 26-27. The manual isolation valves for the HCU were already closed to isolate the maintenance area. However, due to seat leakage past one or both of the manual isolation valves, the leakage continued and degraded to the point that a visible plume of steam was issuing from the valve. Further, high airborne activity level developed in the vicinity of the HCU bank in the Reactor Building. As a precaution, the Control Room supervisor (CRS) evacuated the Reactor Building at 0125 CDT. At 0200 CDT, the CRS entered the station reactor scram procedure and performed the preparation steps of transferring electrical loads to the startup transformer. At 0212 CDT, the reactor was manually scrammed. All rods inserted normally. A Group 2 containment isolation signal was received on low reactor water level at 3". During the recovery, the remaining reactor feed pump was manually tripped at 50" in accordance with station procedures due to high RPV level conditions. 'B' RFP was restarted when conditions permitted and is being used to control RPV level. RPV pressure is being controlled by the bypass valves rejecting heat to the main condenser. This report is being submitted pursuant to 50.72 (2)(iv) for a critical scram and specified system actuation for the Group 2 containment isolation. Currently, the leak into the Reactor Building has stopped. Radiological conditions are being assessed and a repair and recovery plan developed. The Senior Resident Inspector has been informed. The scram was characterized as uncomplicated and all systems functioned as required. No personnel contaminations or off-site releases occurred due to the HCU valve leak. |
| Where | |
|---|---|
Cooper  Nebraska (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| LER: | 05000298/LER-2007-004 |
| Time - Person (Reporting Time:+-1.77 h-0.0738 days <br />-0.0105 weeks <br />-0.00242 months <br />) | |
| Opened: | Roy Giles 05:26 May 19, 2007 |
| NRC Officer: | Bill Huffman |
| Last Updated: | May 19, 2007 |
| 43375 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | Yes, Manual Scram |
| Before | Power Operation (50 %) |
| After | Hot Shutdown (0 %) |
Cooper with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
WEEKMONTHYEARENS 562782022-12-17T05:51:00017 December 2022 05:51:00
[Table view]10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram ENS 562202022-11-13T04:19:00013 November 2022 04:19:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram ENS 561742022-10-22T17:58:00022 October 2022 17:58:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge ECCS Injection While Shutdown ENS 549762020-11-01T10:34:0001 November 2020 10:34:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip Due to an Un-Isolable Leak on the Turbine High Pressure Fluid System ENS 522612016-09-25T06:03:00025 September 2016 06:03:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Actuation of Group 1 Isolation Signal ENS 454892009-11-11T23:43:00011 November 2009 23:43:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram After a Turbine Hydraulic Fluid Leak ENS 454822009-11-07T01:30:0007 November 2009 01:30:00 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 an Unisolable Leak on the Turbine High Pressure Fluid System ENS 444022008-08-09T07:04:0009 August 2008 07:04:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram Due to Failure of Reheat Stop Valve to Open During Turbine Valve Testing ENS 433752007-05-19T07:12:00019 May 2007 07:12:00 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 Control Rod Hcu Valve Bonnet Leak Into Reactor Building ENS 425942006-05-22T12:01:00022 May 2006 12:01:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram as a Mitigating Action Due to Lowering Service Air Pressure ENS 423752006-02-26T08:50:00026 February 2006 08:50:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram Due to Msr High Level ENS 420102005-09-23T05:40:00023 September 2005 05:40:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram Due to Degrading Main Condenser Vacuum ENS 416012005-04-15T09:36:00015 April 2005 09:36:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Reactor Scram and Specified System Actuations ENS 403622003-11-29T04:02:00029 November 2003 04:02:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Automatic Scram Due to Low Reactor Water Level 2022-12-17T05:51:00 | |