05-19-2017 | On March 23, 2017, at 0941, Eastern Daylight Time (EDT), with Unit 2 in Mode 1 at 100% power, the Unit 2 Containment CEQ Fan #1 Backdraft Damper opening force exceeded the Technical Specification (TS) Surveillance Requirement (SR) limit.
Maintenance was performed on the damper and operability of the Unit 2 CEQ Fan #1 was restored at 1724 EDT. A past operability evaluation was performed and determined that the condition likely existed since maintenance was performed to lubricate the damper on February 24, 2017. As a result, the Unit 2 CEQ Fan #1 was inoperable longer than allowed by TS. During this time, the Unit 2 CEQ Fan #2 was declared inoperable to perform surveillance testing on March 2, 2017, from 0938 Eastern Standard Time (EST) until 1326 EST. This resulted in both trains being inoperable simultaneously for a short period of time.
The cause of the elevated force required to open the Unit 2 CEQ Fan #1 Backdraft Damper was determined to be that the lubrication Preventive Maintenance (PM) work order instructions were not adequate and did not provide adequate Post-Maintenance Testing (PMT) instruction. Corrective action is to revise model work order tasks to provide additional details and appropriate PMT. The risk significance of this condition has been determined to not constitute a significant increase in risk.
This event is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B) and 10 CFR 50.73(a)(2)(v)(D). |
---|
Similar Documents at Cook |
---|
Category:Letter
MONTHYEARIR 05000315/20230042024-01-31031 January 2024 Integrated Inspection Report 05000315/2023004 and 05000316/2023004 ML24004A1582024-01-19019 January 2024 Exemption from Select Requirements of 10 CFR Part 73 (EPID L-2023-LLE-0039 (Security Notifications, Reports, and Recordkeeping and Suspicious Activity Reporting)) AEP-NRC-2024-01, Emergency Plan Revision 482024-01-0808 January 2024 Emergency Plan Revision 48 AEP-NRC-2023-56, Report Per Technical Specification 5.6.6 for Inoperability of Unit 1 Post Accident Monitoring Reactor Coolant (Loop 3 Cold Leg) Wide Range Temperature Recorder Thermal Sensor2023-12-20020 December 2023 Report Per Technical Specification 5.6.6 for Inoperability of Unit 1 Post Accident Monitoring Reactor Coolant (Loop 3 Cold Leg) Wide Range Temperature Recorder Thermal Sensor ML23352A3502023-12-19019 December 2023 Dc. Cook Nuclear Power Plant, Units 1 Biennial Licensed Operator Requalification Program Inspection and Request for Information ML23338A2642023-12-0505 December 2023 Confirmation of Initial License Examination AEP-NRC-2023-45, Unit 2 - Schedular Exemption for Enhanced Weapons, Firearms, Background Checks, and Security Event Notifications Implementation2023-11-16016 November 2023 Unit 2 - Schedular Exemption for Enhanced Weapons, Firearms, Background Checks, and Security Event Notifications Implementation IR 05000315/20234042023-11-0606 November 2023 Cyber Security Inspection Report 05000315/2023404 and 05000316/2023404 ML23310A1152023-11-0606 November 2023 Notification of the NRC Baseline Inspection and Request for Information, Inspection Report 05000316/2024002 IR 05000315/20234032023-09-19019 September 2023 Security Baseline Inspection Report 05000315/2023403 and 05000316/2023403 IR 05000315/20230112023-08-31031 August 2023 Functional Engineering Inspection - Commercial Grade Dedication Report 05000315/2023011 and 05000316/2023011 ML23242A1832023-08-30030 August 2023 Notification of NRC Baseline Inspection and Request for Information; Inspection Report05000315/2023004 AEP-NRC-2023-40, Annual Report of Loss-of-Coolant Accident Evaluation Model Changes2023-08-29029 August 2023 Annual Report of Loss-of-Coolant Accident Evaluation Model Changes IR 05000315/20234022023-08-11011 August 2023 Security Baseline Inspection Report 05000315/2023402 and 05000316/2023402 AEP-NRC-2023-34, Supplement to Request for Approval of Change Regarding Neutron Flux Instrumentation2023-08-0202 August 2023 Supplement to Request for Approval of Change Regarding Neutron Flux Instrumentation IR 05000315/20230022023-07-24024 July 2023 Integrated Inspection Report 05000315/2023002 and 05000316/2023002 ML23178A2422023-06-28028 June 2023 Reassignment of the U.S. Nuclear Regulatory Commission Branch Chief in the Division of Operating Reactor Licensing for Plant Licensing Branch III IR 05000315/20230122023-06-22022 June 2023 Biennial Problem Identification and Resolution Inspection Report 05000315/2023012 and 05000316/2023012 IR 05000315/20235012023-06-21021 June 2023 Emergency Preparedness Biennial Exercise Inspection Report 05000315/2023501 and 05000316/2023501 AEP-NRC-2023-29, Core Operating Limits Report2023-06-19019 June 2023 Core Operating Limits Report ML23159A0192023-06-13013 June 2023 Information Meeting with a Question and Answer Session to Discuss NRC 2022 End-Of-Cycle Plant Performance Assessment of Donald C. Cook Nuclear Plant, Units 1 and 2 AEP-NRC-2023-32, Response to NRC Regulatory Issue Summary 2023-1 Preparation and Scheduling of Operator Licensing Examinations2023-06-0606 June 2023 Response to NRC Regulatory Issue Summary 2023-1 Preparation and Scheduling of Operator Licensing Examinations AEP-NRC-2023-33, Renewable Operating Permit2023-06-0505 June 2023 Renewable Operating Permit AEP-NRC-2023-30, Follow-Up Notification of Ph Non-Compliance for Turbine Room Sump2023-06-0101 June 2023 Follow-Up Notification of Ph Non-Compliance for Turbine Room Sump AEP-NRC-2023-27, Annual Radiological Environmental Operating Report2023-05-15015 May 2023 Annual Radiological Environmental Operating Report ML23131A3282023-05-11011 May 2023 D.C. Cook Information Request for the Cyber-Security Baseline Inspection, Notification to Perform Inspection 05000315/2023404 and 05000316/2023404 IR 05000315/20230012023-05-0303 May 2023 Integrated Inspection Report 05000315/2023001 and 05000316/2023001 AEP-NRC-2023-19, Annual Radioactive Effluent Release Report2023-04-30030 April 2023 Annual Radioactive Effluent Release Report ML23117A0062023-04-27027 April 2023 Review of the Spring 2022 Steam Generator Tube Inspections Report ML23114A1142023-04-25025 April 2023 Information Request to Support the NRC Annual Baseline Emergency Action Level and Emergency Plan Changes Inspection AEP-NRC-2023-23, Annual Report of Individual Monitoring for 20222023-04-24024 April 2023 Annual Report of Individual Monitoring for 2022 AEP-NRC-2023-24, Notification of Ph Non-Compliance for Turbine Room Sump2023-04-12012 April 2023 Notification of Ph Non-Compliance for Turbine Room Sump AEP-NRC-2023-20, Annual Report of Property Insurance2023-04-0303 April 2023 Annual Report of Property Insurance AEP-NRC-2023-15, Decommissioning Funding Status Report2023-03-28028 March 2023 Decommissioning Funding Status Report ML23076A0212023-03-20020 March 2023 Request for Information for NRC Commercial Grade Dedication Inspection; Inspection Report 05000315/2023011; 05000316/2023011 IR 05000315/20234012023-03-16016 March 2023 Security Baseline Inspection Report 05000315/2023401 and 05000316/2023401 ML23066A1882023-03-0707 March 2023 Information Request to Support Upcoming Problem Identification and Resolution (Pi&R) Inspection at Donald C. Cook Nuclear Plant IR 05000315/20220062023-03-0101 March 2023 Annual Assessment Letter for Donald C. Cook Nuclear Plant, Units 1 and 2 (Report 05000315/2022006 and 05000316/2022006) IR 05000315/20220042023-02-0101 February 2023 Integrated Inspection Report 05000315/2022004 and 05000316/2022004 and Exercise of Enforcement Discretion AEP-NRC-2023-11, Form OAR-1, Owner'S Activity Report2023-01-31031 January 2023 Form OAR-1, Owner'S Activity Report IR 05000315/20230102023-01-31031 January 2023 Phase 4 Post-Approval License Renewal Inspection Report 05000315/2023010 and 05000316/2023010 AEP-NRC-2023-02, Request for Approval of Change Regarding Neutron Flux Instrumentation2023-01-26026 January 2023 Request for Approval of Change Regarding Neutron Flux Instrumentation ML22363A5622023-01-0404 January 2023 Relief Request ISIR-5-06 Related to ASME Code Case N-729-6 Supplemental Examination Requirements of Reactor Vessel Closure Head Penetration Nozzles AEP-NRC-2022-66, Report Per Technical Specification 5.6.6 for Inoperability of Unit 2 Post Accident Monitoring Neutron Flux Monitoring2022-12-15015 December 2022 Report Per Technical Specification 5.6.6 for Inoperability of Unit 2 Post Accident Monitoring Neutron Flux Monitoring AEP-NRC-2022-46, Notification of Deviation from Electric Power Research Institute (EPRI) Materials Reliability Program 2019-008, Interim Guidance for NEI 03-08 Needed Requirements for Us PWR Plants for Management of Thermal Fatigue in2022-12-12012 December 2022 Notification of Deviation from Electric Power Research Institute (EPRI) Materials Reliability Program 2019-008, Interim Guidance for NEI 03-08 Needed Requirements for Us PWR Plants for Management of Thermal Fatigue in ML22340A1392022-11-30030 November 2022 Submittal of Revision 31 to Updated Final Safety Analysis Report and 10CFR50.71(e) Updated and Related Site Change Reports IR 05000315/20220112022-11-0404 November 2022 Design Basis Assurance Inspection (Teams) Inspection Report 05000315/2022011 and 05000316/2022011 IR 05000315/20220032022-10-28028 October 2022 Integrated Inspection Report 05000315/2022003 and 05000316/2022003 AEP-NRC-2022-58, U1C31 Steam Generator Tube Inspection Report2022-10-24024 October 2022 U1C31 Steam Generator Tube Inspection Report AEP-NRC-2022-61, Request for Relief Related to American Society of Mechanical Engineers (ASME) Code Case N-729-6 Supplemental Examination Requirements, ISIR-5-062022-10-24024 October 2022 Request for Relief Related to American Society of Mechanical Engineers (ASME) Code Case N-729-6 Supplemental Examination Requirements, ISIR-5-06 2024-01-08
[Table view] Category:Licensee Event Report (LER)
MONTHYEAR05000316/LER-2017-0012017-05-19019 May 2017 1 OF 5, LER 17-001-00 for Cook, Unit 2 re Containment Hydrogen Skimmer Ventilation Fan #1 Inoperable Longer than Allowed by Technical Specifications 05000316/LER-2016-0022017-02-0909 February 2017 Emergency Diesel Generators Declared Inoperable Due to a Manufacturing Design Issue, LER 16-002-00 for Donald C. Cook Nuclear Plant Unit 2 Regarding Emergency Diesel Generators Declared Inoperable Due to a Manufacturing Design Issue 05000316/LER-2016-0012016-08-31031 August 2016 Manual Reactor Trip Due To Moisture Separator Heater Expansion Joint Failure, LER 16-001-00 for Donald C. Cook Nuclear Plant, Unit 2 Regarding Manual Reactor Trip Due To Moisture Separator Heater Expansion Joint Failure ML16193A3902016-07-15015 July 2016 Donald C. Cook Nuclear Plant Unit 2 - A Loss of Main Condenser Event Occurred Due to a Storm-Induced Debris Damage of the Circulating Water System Pumps in the Forebay (LER-316-2014-003-00) 05000315/LER-2015-0022016-01-18018 January 2016 -Technical Specification Violation due to Inoperable Residual. Heat Removal Pump, LER 15-002-01 for D.C. Cook, Unit 1, Regarding Technical Specification Violation Due to Inoperable Residual Heat Removal Pump 05000316/LER-2015-0012016-01-15015 January 2016 Manual Reactor Trip Due To A Secondary Plant Transient, LER 15-001-01 for D.C. Cook, Unit 2, Regarding Manual Reactor Trip Due to a Secondary Plant Transient ML0528703602005-10-0505 October 2005 Special Report for D. C. Cook Unit 2 Re Unit 2 Reactor Coolant Inventory Tracking System ML0508903452005-03-22022 March 2005 LER 99-001-01 Donald C. Cook Nuclear Plant Unit 2, Regarding Supplemental LER for Degraded Component Cooling Water Flow to Containment Main Steam Line Penetrations ML0210601432002-04-12012 April 2002 LER 02-02-00, Donald C. Cook Nuclear Plant Unit 2, Technical Specification 3.9.4.c Was Violated During Core Alteration ML0209205342002-03-15015 March 2002 LER 99-012-01 for Cook Nuclear Plant, Unit 1 Re Auxiliary Building ESF Ventilation System May Not Be Capable of Maintaining ESF Room Temperature Post-Accident ML9936300511999-12-20020 December 1999 LER 99-S004-00, Intentionally Falsifying Documentation Results in Unauthorized Unescorted Access, on 11/18/99. with Letter Dated 12/20/99 ML9934002411999-11-29029 November 1999 LER 315/99-027-00, Underrated Fuses Used in 250 Vdc System Could Result in Lack of Protective Coordination ML18219B5201978-09-27027 September 1978 09/27/1978 Letter Enclosure of Licensee Event Report ML18219E1521978-09-27027 September 1978 Submit Licensee Event Report Nos. RO 78-051/03L-0 & RO 78-052/03L-0 ML18219B5211978-09-19019 September 1978 09/19/1978 Letter Enclosure of Licensee Event Report ML18219E1531978-09-18018 September 1978 Submit Licensee Event Report No. RO 78-050/03L-0 ML18219B5541978-09-18018 September 1978 Letter from Indiana & Michigan Power Co to NRC Submitting Licensee Event Report (RO 78-062/03L-0) ML18219B5551978-09-12012 September 1978 Letter from Indiana & Michigan Power Co to NRC Submitting Licensee Event Reports (RO 78-56/03L-1 and RO 78-061/03L-0) ML18219E1541978-09-12012 September 1978 Submit Licensee Event Report No. RO 78-049/03L-0 ML18219B5561978-09-0808 September 1978 Letter from Indiana & Michigan Power Co to NRC Submitting Licensee Event Reports (RO 78-059/03L-1 and RO 78-060/03L-0) ML18219E1551978-09-0808 September 1978 Submit Licensee Event Report No. RO 78-048/03L-0 ML18219B5571978-09-0505 September 1978 Letter from Indiana & Michigan Power Co to NRC Submitting License Event Report RO 78-059/03L-0 ML18219B5581978-08-30030 August 1978 Letter from Indiana & Michigan Power Co to NRC Submitting Licensee Event Report RO 78-058/03L-0 ML18219B5621978-08-22022 August 1978 Letter from Indiana & Michigan Power Co to NRC Submitting Licensee Event Reports (RO 78-056/03L-0 and RO 78-057/03L-0) ML18219B5611978-08-18018 August 1978 Letter from Indiana & Michigan Power Co to NRC Submitting Licensee Event Reports (RO 78-052/03L-0, RO 78-053/03L-0, RO 78-054-03L-0 and RO 78-055/03L-0) ML18219E1561978-08-15015 August 1978 Submit Licensee Event Report No. RO 78-047/03L-0 ML18219E1571978-08-14014 August 1978 Submit Licensee Event Report Nos. RO 78-045/03L-0 & RO 78-046/03L-0 ML18219E1581978-08-14014 August 1978 Submit Licensee Event Report Nos. RO 78-043/03L-1 & RO 78-044/03L-1 ML18219E1601978-08-11011 August 1978 Submit Licensee Event Report Nos. 1978-043-03L & 1978-044-03L ML18219B5641978-08-10010 August 1978 Letter from Indiana & Michigan Power Co to NRC Submitting Licensee Event Report (RO 78-051/03L-0) ML18219B5651978-08-0909 August 1978 Letter from Indiana & Michigan Power Co to NRC Submitting Licensee Event Report (RO 78-049/03L-1) ML18219B5661978-08-0808 August 1978 Letter from Indiana & Michigan Power Co to NRC Submitting Licensee Event Report (RO 78-050/03L-0) ML18219B5671978-08-0404 August 1978 Letter from Indiana & Michigan Power Co to NRC Submitting Licensee Event Report (RO 78-049/03L-0) ML18219B5681978-08-0202 August 1978 Letter from Indiana & Michigan Power Co to NRC Submitting Licensee Event Reports (RO 78-029/03L-1 and RO 78-048/03L-0) ML18219B5691978-07-21021 July 1978 Letter from Indiana & Michigan Power Co to NRC Submitting Licensee Event Reports (RO 78-019/03L-1 and RO 78-023/03L-1) ML18219B5701978-07-18018 July 1978 Letter from Indiana & Michigan Power Co to NRC Submitting Licensee Event Report (RO 78-047/03L-0) ML18219B5711978-07-11011 July 1978 Letter from Indiana & Michigan Power Co to NRC Submitting Licensee Event Report (RO 78-043/03L-0), Submitted Late Due to a Paper Defect ML18219B5721978-07-11011 July 1978 Letter from Indiana & Michigan Power Co to NRC Submitting Licensee Event Reports (RO 78-034/03L-1, RO 78-044/03L-0, RO 78-045/03L-0, RO 78-046/03L-0) ML18219B5731978-07-0505 July 1978 Letter from Indiana & Michigan Power Co to NRC Submitting Licensee Event Report (RO 78-042/03L-0) ML18219B5751978-06-29029 June 1978 Letter from Indiana & Michigan Power Co to NRC Submitting Licensee Event Report (RO 50-316/78-037), Stating Corrective Actions Taken IR 05000316/19780371978-06-29029 June 1978 Letter from Indiana & Michigan Power Co to NRC Submitting Licensee Event Report (RO 50-316/78-037), Stating Corrective Actions Taken ML18219B5771978-06-22022 June 1978 D.C. Cook - Submit Licensee Event Report RO 78-036/03L-0 for Unit 2 ML18219B5761978-06-21021 June 1978 Letter from Indiana & Michigan Power Co to NRC Submitting Licensee Event Report (RO 78-035/03L-0), a Resubmittal of LER 78-034/03L-0 Dated 6/19/1978 IR 05000316/19780341978-06-19019 June 1978 D.C. Cook - Submit Licensee Event Report RO 50-316/78-034/03L-0 for Unit 2 ML18219B5781978-06-19019 June 1978 D.C. Cook - Submit Licensee Event Report RO 50-316/78-034/03L-0 for Unit 2 ML18219B5221978-06-0606 June 1978 06/06/1978 Letter Licensee Event Report ML18219B5741978-06-0303 June 1978 Letter from Indiana & Michigan Power Co to NRC Submitting Licensee Event Reports (RO 78-038/03L-0, RO 78-039/03L-0, RO 78-040/03L-0, RO 78-041/03L-0) ML18219B5241978-06-0202 June 1978 06/02/1978 Letter Licensee Event Report ML18219B5231978-06-0202 June 1978 06/02/1978 Letter Licensee Event Report ML18219B5251978-05-25025 May 1978 05/25/1978 Letter Licensee Event Report 2017-05-19
[Table view] |
Reported lessons learned are incorporated into the licensing process and fed back to industry.
Send comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
EVENT DESCRIPTION
On March 23, 2017, at 0941 EDT, with Unit 2 in Mode 1 at 100% power, the Unit 2 CEQ [BB] Fan #1 [FAN] was declared inoperable to perform surveillance testing. At 1116 EDT, it was identified that the surveillance failed to meet acceptance criteria due to the Unit 2 CEQ Fan #1 Backdraft Damper [UDMP] opening force exceeding the TS operability limit by approximately 0.5 pounds. There were no automatic or manual safety system responses initiated as a result of this event.
Maintenance and Engineering personnel entered containment to inspect and repair the damper. As-found inspection concluded that the opening force was exceeded due to increased bearing resistance. Maintenance greased and cycled the damper to correct the condition. A partial surveillance was successfully performed following maintenance. On March 23, 2017, at 1724 EDT, Operations reported that all surveillance acceptance criteria were met and the Unit 2 CEQ Fan #1 was declared operable. The Unit 2 CEQ Fan #1 was declared operable and returned to service approximately six hours and eight minutes after the discovery of the failure of Unit 2 CEQ Fan #1 Backdraft Damper.
Per TS SR 3.6.10.3, the opening force of the Unit 2 CEQ Fan #1 Backdraft Damper is surveilled quarterly. The last surveillance was performed on November 30, 2016, and all surveillance acceptance criteria were met. Because the CEQ System is normally in standby, the damper is only cycled during PM activities and the quarterly surveillance.
Based on review of the last surveillances, there was no indication or trend that the system would not be able to meet all surveillance requirements during the surveillance performed on March 23, 2017.
The last PM activity performed on the Unit 2 CEQ Fan #1 Backdraft Damper was performed February 24, 2017.
The Maintenance group that normally performs this PM activity did not perform the work on February 24, 2017.
Interviews were conducted with both the group that normally performs this work and the group who performed the work on February 24, 2017. Based on the interviews, there were notable differences in work practices between the groups related to cycling the dampers following bearing lubrication. Cycling the damper is the PMT for the bearing lubrication PM. Although the work order contains a note that clarifies cycling the damper is approved and acceptable, based on the interviews conducted, the personnel who performed the work on February 24, 2017 were more cautious in cycling the damper numerous times and did not cycle the damper as many times as the Maintenance group that normally performs this task.
The backdraft damper likely failed to meet acceptance criteria due to the lack of cycling following the February 24, 2017, PM before being returned to service. This resulted in the grease not being distributed thoroughly around the bearings resulting in a localized area of over greasing. Too much grease volume (over greasing) in a bearing element is known to cause increased resistance for the bearing to rotate. This increased resistance would result in more force required to open the damper. The elevated force required to open the Unit 2 CEQ Fan #1 Backdraft Damper could potentially lead to a partial opening of the damper upon fan start up that could result in not providing the design required air flow.
The Unit 2 CEQ Fan #1 was considered inoperable from the point of hanging the clearance to perform the PM on February 24, 2017, at 2045 EST, until the corrective maintenance was completed on March 23, 2017, at 1724 EDT, following the failed surveillance. The allowed outage time (AOT) for TS 3.6.10 condition "A" (One CEQ Train Inoperable) is 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. This AOT was exceeded and is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B) as an operation or condition which was prohibited by TS.
Donald C. Cook Nuclear Plant Unit 2 05000316 Reported lessons learned are incorporated into the licensing process and fed back to industry.
Send comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
On March 2, 2017, from 0938 EST until 1326 EST, Unit 2 CEQ Fan #2 was declared inoperable to perform scheduled quarterly surveillance testing. During this time, both Unit 2 CEQ Fan trains were inoperable which is reportable in accordance with 10 CFR 50.73(a)(2)(v)(D) as an event or condition that could have prevented the fulfillment of a safety function of a system that is needed to mitigate the consequences of an accident.
DATES AND APPROXIMATE TIMES OF OCCURRENCES:
November 30, 2016, quarterly surveillance testing for Unit 2 CEQ Fan #1 and Unit 2 CEQ Fan #1 Backdraft Damper was performed satisfactorily.
February 24, 2017, at 2045 EST, Unit 2 CEQ Fan #1 was declared inoperable for performance of PM work order task to inspect and lubricate Unit 2 CEQ Fan #1 and its associated backdraft damper (18 month frequency). The PM WOT was completed and the Unit 2 CEQ Fan #1 was declared operable on February 25, 2017, at 0250 EST.
March 2, 2017, at 0938 EST, Unit 2 CEQ Fan #2 was declared inoperable for performance of quarterly surveillance testing. Surveillance was completed satisfactorily and Unit 2 CEQ Fan #2 was declared operable at 1326 EST.
March 23, 2017, at 0941 EDT, Unit 2 CEQ Fan #1 was declared inoperable for performance of quarterly surveillance testing.
March 23, 2017, at 1116 EDT, Unit 2 CEQ Fan #1 Backdraft Damper failed surveillance acceptance criterion for opening force. Maintenance and Engineering personnel performed a walkdown of the failed equipment; Maintenance personnel greased and cycled the damper, tested the opening force of the damper, and performed a partial surveillance that verified the as-left opening force met the acceptance criterion.
March 23, 2017, at 1724 EDT, Operations declared the Unit 2 CEQ Fan #1 operable.
MANUFACTURER AND MODEL NUMBER (OR OTHER IDENTIFICATION) OF EACH COMPONENT THAT
FAILED DURING THE EVENT:
The Unit 2 CEQ Fan #1 Backdraft Damper is an American Warming and Ventilation, Inc. Model DAA-P-7900.
OTHER SYSTEMS OR SECONDARY FUNCTIONS AFFECTED:
The CEQ system has three safety related functions:
1. Distribute hydrogen to eliminate pocketing in the upper and lower containment compartments 2. Assists ice melt during a Loss of Coolant Accident (LOCA) or Main Steam Line Break (MSLB) 3. Assists iodine removal by promoting mixing Failure of the damper to provide a proper flow path will impact all three safety functions of the system.
Donald C. Cook Nuclear Plant Unit 2 05000316 Reported lessons learned are incorporated into the licensing process and fed back to industry.
Send comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
CAUSE OF THE EVENT
THE CAUSE OF EACH COMPONENT OR SYSTEM FAILURE OR PERSONNEL ERROR, IF KNOWN:
The apparent cause of the Unit 2 CEQ Fan #1 Backdraft Damper failure was determined to be the lubrication PM WOT instructions were not adequate and did not provide adequate PMT to ensure the damper could meet the Surveillance and TS required criteria for opening force after completion.
THE CAUSE(S) AND CIRCUMSTANCES FOR EACH HUMAN PERFORMANCE RELATED CAUSE:
This event was not attributed to human error because the Maintenance Technicians performed the PM task in accordance with written instructions.
ASSESSMENT OF SAFETY CONSEQUENCES
NUCLEAR SAFETY
The failure of the Unit 2 CEQ Fan #1 Backdraft Damper to meet surveillance acceptance criteria did not result in an actual nuclear safety impact.
The CEQ System is a standby system that actuates post-accident to assure the rapid return of air from the upper to lower containment compartment. Circulation of air from upper to lower containment promotes mixing to prevent hydrogen buildup and assists in minimizing post-accident containment pressure and temperature.
Returning air to the lower compartment subsequently provides airflow for recirculation through the Ice Condenser. CEQ Ventilation, in conjunction with the Ice Condenser, Containment Spray and Residual Heat Removal is credited in the LOCA and MSLB analysis to provide the required heat removal to maintain Containment within design values.
CEQ consists of two separate, 100% capable trains. Each train includes a fan, backdraft damper, two upper compartment headers and a hydrogen skimmer header isolation valve. The fan provides the motive force to circulate air from the upper compartment to the lower compartment. The backdraft damper prevents backflow during initial blowdown and during operation of the redundant train. The Unit 2 CEQ Fan #2 was operable and available during the time that Fan #1 was inoperable except for the period on March 2, 2017, from 0938 EST to 1326 EST.
INDUSTRIAL SAFETY
There was no actual or potential industrial safety hazard resulting from this event.
RADIOLOGICAL SAFETY
There was no actual or potential radiological safety hazard resulting from this event.
Donald C. Cook Nuclear Plant Unit 2 05000316 Reported lessons learned are incorporated into the licensing process and fed back to industry.
Send comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
PROBABILISTIC RISK ASSESSMENT (PRA) The goal of PRA is to model plant response to accident scenarios in order to determine Core Damage Frequency and Large Early Release Frequency. The components affected in this event assist in the distribution of hydrogen post-accident to prevent pocket formation, assist in melting the ice during a LOCA or MSLB, and assist in the removal of iodine following an accident to reduce containment atmosphere activity. The CEQ fans that were inoperable during this event are not explicitly modeled within the PRA. Thermal-hydraulic analysis shows that the fans are not necessary to reach a safe shutdown state post-accident, and therefore are not credited within the PRA. For this reason, the inoperability of the CEQ fans and backdraft damper had no impact on site PRA risk.
AVAILABILITY OF SYSTEMS OR COMPONENTS THAT COULD HAVE PERFORMED THE SAME FUNCTION AS
THE COMPONENTS AND SYSTEMS THAT FAILED DURING THE EVENT:
The Distributed Ignition System [BB] was available to prevent hydrogen pocket formation during this event.
CORRECTIVE ACTIONS:
IMMEDIATE CORRECTIVE ACTIONS:
On March 23, 2017, Maintenance personnel greased and cycled the damper and tested the opening force of the damper to verify the as-left opening force met the surveillance acceptance criterion. Operations personnel reported the acceptance criteria were met at 1724 EDT, the damper/fan was declared Operable and TS 3.6.10 condition "A" was exited. System Engineering personnel reviewed the most recent test data for the other three trains of CEQ and validated all backdraft dampers had satisfactorily met the acceptance criteria since the last performance of the lubrication PM.
CORRECTIVE ACTIONS TO REDUCE THE PROBABILITY OF SIMILAR EVENTS OCCURRING IN THE FUTURE:
Corrective action to reduce the probability of similar occurrence in the future is to revise the model PM WOTs for CEQ fan and damper inspection and lubrication to include additional details and appropriate PMT.
PREVIOUS SIMILAR EVENTS:
An Operating Experience search was performed in the corrective action program for similar failures of CEQ fan backdraft dampers exceeding the maximum opening force requirement.
In 2004, the Unit 2 CEQ Fan #1 Backdraft Damper failed the quarterly surveillance for damper opening force. The damper bearings were lubed, cycled and subsequently passed the surveillance.
A review of CNP LERs for the past three years was also performed and did not identify any previously reported similar events.
Donald C. Cook Nuclear Plant Unit 2 05000316