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Category:Letter
MONTHYEARML25022A2962025-01-23023 January 2025 Technical Specification Bases Pages ML25023A0392025-01-23023 January 2025 Senior Reactor and Reactor Operator Initial License Examinations L-25-001, Endorsement of Framatomes Requested Review Schedule for Topical Report ANP-10358P, Revision O Increased Burnup for PWRs2025-01-23023 January 2025 Endorsement of Framatomes Requested Review Schedule for Topical Report ANP-10358P, Revision O Increased Burnup for PWRs ML25014A2862025-01-21021 January 2025 Alternative Request to Defer ASME Code Section XI Inservice Inspection Examinations for Pressurizer and Steam Generator Pressure-Retaining Welds and Full Penetration Welded Nozzles IR 05000336/20244032025-01-13013 January 2025 Cyber Security Inspection Report 05000336/2024403 and 05000423/2024403 (Cover Letter Only) ML24365A2032024-12-30030 December 2024 ISFSI - 10 CFR 72.30 Decommissioning Funding Plan ML24351A2422024-12-19019 December 2024 Reactor Coolant System Alloy 600 Inspection Program for License Renewal Commitment No. 15 ML24351A2412024-12-19019 December 2024 Reactor Vessel Internals Inspections Aging Management Program Submittal Related to License Renewal Commitment No. 13 ML24346A2532024-12-12012 December 2024 Correction to Implementation Date for License Amendment No. 291 Regarding Framatome Gaia Fuel IR 05000336/20243012024-12-0606 December 2024 Initial Operator Licensing Examination Report 05000336/2024301 ML24324A0442024-12-0303 December 2024 Issuance of Amendment No. 292 Regarding Adoption of Technical Specification Task Force Traveler TSTF-421 05000336/LER-2024-002, Two Main Steam Safety Valves Failed to Lift within the Acceptance Criteria Resulting in a Condition Prohibited by Technical Specifications2024-11-26026 November 2024 Two Main Steam Safety Valves Failed to Lift within the Acceptance Criteria Resulting in a Condition Prohibited by Technical Specifications 05000423/LER-2024-002, Door Latch Failure Resulted in Loss of Safety Function for Secondary Containment Boundary2024-11-26026 November 2024 Door Latch Failure Resulted in Loss of Safety Function for Secondary Containment Boundary ML24296B2352024-11-19019 November 2024 Issuance of Amendment No. 291 License Amendment to Support the Implementation of Framatome Gaia Fuel (EPID L-2023-LLA-0150) (Non-Proprietary) IR 05000245/20240012024-11-12012 November 2024 Safstor Inspection Report 05000245/2024001 ML24317A2562024-11-12012 November 2024 Core Operating Limits Report, Gycle 30 IR 05000336/20240032024-11-0707 November 2024 Integrated Inspection Report 05000336/2024003 and 05000423/2024003 and Apparent Violation and Independent Spent Fuel Storage Installation Inspection Report 07200008/2024001 ML24289A0152024-10-21021 October 2024 Review of the Fall 2023 Steam Generator Tube Inspection Report 05000423/LER-2024-001, Loss of Safety Function and Condition Prohibited by Technical Specifications for Loss of Secondary Containment Boundary2024-10-14014 October 2024 Loss of Safety Function and Condition Prohibited by Technical Specifications for Loss of Secondary Containment Boundary IR 05000336/20244022024-10-0808 October 2024 Security Baseline Inspection Report 05000336/2024402 and 05000423/2024402 (Cover Letter Only) ML24281A1102024-10-0707 October 2024 Requalification Program Inspection 05000423/LER-2023-006-02, Pressurizer Power Operated Relief Valve Failed to Open During Surveillance Testing Resulting in a Condition Prohibited by Technical Specifications2024-09-26026 September 2024 Pressurizer Power Operated Relief Valve Failed to Open During Surveillance Testing Resulting in a Condition Prohibited by Technical Specifications ML24240A1692024-09-18018 September 2024 Cy 2023 Summary of Decommissioning Trust Fund Status ML24260A1952024-09-16016 September 2024 Response to Request for Additional Information Regarding Proposed Amendment to Support Implementation of Framatome Gaia Fuel ML24260A2192024-09-16016 September 2024 Decommissioning Trust Fund Disbursement - Revision to Previous Thirty-Day Written Notification ML24248A2272024-09-0404 September 2024 Operator Licensing Examination Approval ML24240A1532024-09-0303 September 2024 Summary of Regulatory Audit Supporting the Review of License Amendment Request for Implementation of Framatome Gaia Fuel IR 05000336/20240052024-08-29029 August 2024 Updated Inspection Plan for Millstone Power Station, Units 2 and 3 (Reports 05000336/2024005 and 05000423/2024005 IR 05000336/20240022024-08-13013 August 2024 Integrated Inspection Report 05000336/2024002 and 05000423/2024002 ML24221A2872024-08-0808 August 2024 Independent Spent Fuel Storage Installation (ISFSI) - Submittal of Cask Registration for Spent Fuel Storage IR 05000336/20244412024-08-0606 August 2024 Supplemental Inspection Report 05000336/2024441 and 05000423/2024441 and Follow-Up Assessment Letter (Cover Letter Only) ML24212A0742024-08-0505 August 2024 Request for Withholding Information from Public Disclosure - Millstone Power Station, Unit No. 3, Proposed Alternative Request IR-4-13 to Support Steam Generator Channel Head Drain Modification ML24211A1712024-07-25025 July 2024 Associated Independent Spent Fuels Storage Installation, Revision to Emergency Plan - Report of Change ML24200A1062024-07-22022 July 2024 Information Request for the Cybersecurity Baseline Inspection, Notification to Perform Inspection 05000336/2024403 and 05000423/2024403 IR 05000336/20245012024-07-0101 July 2024 Emergency Preparedness Biennial Exercise Inspection Report 05000336/2024501 and 05000423/2024501 ML24180A0932024-06-28028 June 2024 Readiness for Additional Inspection: EA-23-144 IR 05000336/20240102024-06-26026 June 2024 Biennial Problem Identification and Resolution Inspection Report 05000336/2024010 and 05000423/2024010 ML24178A2422024-06-25025 June 2024 2023 Annual Report of Emergency Core Cooling System (ECCS) Model, Changes Pursuant to the Requirements of 10 CFR 50.46 IR 05000336/20244402024-06-24024 June 2024 Final Significance Determination for Security-Related Greater than Green Finding(S) with Assessment Follow-up; IR 05000336/2024440 and 05000423/2024440 and Notice of Violation(S), NRC Investigation Rpt 1-2024-001 (Cvr Ltr Only) ML24281A2072024-06-20020 June 2024 Update to the Final Safety Analysis Report, Revision 37 (Redacted Version) ML24177A2792024-06-20020 June 2024 Preparation and Scheduling of Operator Licensing Examinations ML24280A0012024-06-20020 June 2024 Update to the Final Safety Analysis Report (Redacted Version) ML24176A1782024-06-20020 June 2024 Update to the Final Safety Analysis Report ML24176A2622024-06-20020 June 2024 Update to the Final Safety Analysis Report, Revision 37 ML24170B0532024-06-10010 June 2024 DOM-NAF-2-P/NP-A, Revision 0.5, Reactor Core Thermal-Hydraulics Using the VIPRE-D Computer Code 05000336/LER-2024-001, Control Room Air Conditioning Unit Inoperable Due to Refrigerant Overcharge Resulting in a Condition Prohibited by Technical Specifications2024-06-10010 June 2024 Control Room Air Conditioning Unit Inoperable Due to Refrigerant Overcharge Resulting in a Condition Prohibited by Technical Specifications ML24170A7832024-06-0606 June 2024 ISFSI, Virgil C. Summer, Unit 1, and ISFSI, North Anna, Units 1 & 2, and ISFSI, Surry, Units 1 & 2, and ISFSI - Submittal of Revision 36 of the Quality Assurance Topical Report ML24165A1292024-06-0505 June 2024 ISFSI, 10 CFR 50.59 Annual Change Report for 2023 Annual Regulatory Commitment Change Report for 2023 ML24128A2772024-06-0404 June 2024 Issuance of Amendment No. 290 to Revise TSs for Reactor Core Safety Limits, Fuel Assemblies, and Core Operating Limits Report for Use of Framatome Gaia Fuel (EPID L-2023-LLA-0074) (Non-Proprietary) ML24151A6482024-06-0303 June 2024 Changes in Reactor Decommissioning Branch Project Management Assignments for Some Decommissioning Facilities 2025-01-23
[Table view] Category:Licensee Event Report (LER)
MONTHYEAR05000423/LER-2024-002, Door Latch Failure Resulted in Loss of Safety Function for Secondary Containment Boundary2024-11-26026 November 2024 Door Latch Failure Resulted in Loss of Safety Function for Secondary Containment Boundary 05000336/LER-2024-002, Two Main Steam Safety Valves Failed to Lift within the Acceptance Criteria Resulting in a Condition Prohibited by Technical Specifications2024-11-26026 November 2024 Two Main Steam Safety Valves Failed to Lift within the Acceptance Criteria Resulting in a Condition Prohibited by Technical Specifications 05000423/LER-2024-001, Loss of Safety Function and Condition Prohibited by Technical Specifications for Loss of Secondary Containment Boundary2024-10-14014 October 2024 Loss of Safety Function and Condition Prohibited by Technical Specifications for Loss of Secondary Containment Boundary 05000423/LER-2023-006-02, Pressurizer Power Operated Relief Valve Failed to Open During Surveillance Testing Resulting in a Condition Prohibited by Technical Specifications2024-09-26026 September 2024 Pressurizer Power Operated Relief Valve Failed to Open During Surveillance Testing Resulting in a Condition Prohibited by Technical Specifications 05000336/LER-2024-001, Control Room Air Conditioning Unit Inoperable Due to Refrigerant Overcharge Resulting in a Condition Prohibited by Technical Specifications2024-06-10010 June 2024 Control Room Air Conditioning Unit Inoperable Due to Refrigerant Overcharge Resulting in a Condition Prohibited by Technical Specifications 05000423/LER-2023-006-01, Pressurizer Power Operated Relief Valve Failed to Open During Surveillance Testing Resulting in a Condition Prohibited by Technical Specifications2024-05-20020 May 2024 Pressurizer Power Operated Relief Valve Failed to Open During Surveillance Testing Resulting in a Condition Prohibited by Technical Specifications 05000423/LER-2023-006, Pressurizer Power Operated Relief Valve Failed to Stroke Open During Surveillance Testing Resulting in a Condition Prohibited by Technical Specifications2024-05-0202 May 2024 Pressurizer Power Operated Relief Valve Failed to Stroke Open During Surveillance Testing Resulting in a Condition Prohibited by Technical Specifications 05000423/LER-2023-005, Oil Leakage from C RSS Pump Motor Challenged Meeting Its Mission Time Resulting in a Condition Prohibited by Technical Specifications2024-02-0808 February 2024 Oil Leakage from C RSS Pump Motor Challenged Meeting Its Mission Time Resulting in a Condition Prohibited by Technical Specifications 05000423/LER-2023-004, For Millstone Power Station, Unit 3 Regarding Reactor Coolant System Pressure Isolation Valves Operational Leakage Exceeded the Acceptance Criteria Resulting in a Condition Prohibited by Technical Specifications2023-12-19019 December 2023 For Millstone Power Station, Unit 3 Regarding Reactor Coolant System Pressure Isolation Valves Operational Leakage Exceeded the Acceptance Criteria Resulting in a Condition Prohibited by Technical Specifications 05000423/LER-2023-003, RCS Temperature Detector Exceeded Time Response Acceptance Criteria Resulting in a Condition Prohibited by Technical Specifications2023-12-0808 December 2023 RCS Temperature Detector Exceeded Time Response Acceptance Criteria Resulting in a Condition Prohibited by Technical Specifications 05000423/LER-2023-002, Auxiliary Feedwater Control Valve Failure Resulting in a Condition Prohibited by Technical Specifications2023-11-30030 November 2023 Auxiliary Feedwater Control Valve Failure Resulting in a Condition Prohibited by Technical Specifications 05000336/LER-2023-002, Failed Check Valve Resulted in an Unanalyzed Condition2023-08-31031 August 2023 Failed Check Valve Resulted in an Unanalyzed Condition 05000423/LER-2023-001, Automatic Reactor Trip Due to Main Generator Output Breaker Ground Fault2023-07-27027 July 2023 Automatic Reactor Trip Due to Main Generator Output Breaker Ground Fault 05000336/LER-2023-001, For Millstone, Unit 2, Structural Integrity of a Train Service Water Header Piping Could Not Be Demonstrated Causing the Unit to Operate in a Condition Prohibited by Technical Specifications2023-07-0707 July 2023 For Millstone, Unit 2, Structural Integrity of a Train Service Water Header Piping Could Not Be Demonstrated Causing the Unit to Operate in a Condition Prohibited by Technical Specifications 05000423/LER-2022-002, Two Main Steam Safety Valves Installed in Wring Location Resulting in Failure to Lift within the Technical Specification Acceptance Criteria2022-05-31031 May 2022 Two Main Steam Safety Valves Installed in Wring Location Resulting in Failure to Lift within the Technical Specification Acceptance Criteria 05000423/LER-2022-001, Emergency Core Cooling and Reactor Plant Component Cooling Water Systems Inoperable for Time Greater than Allowed by Technical Specifications2022-03-24024 March 2022 Emergency Core Cooling and Reactor Plant Component Cooling Water Systems Inoperable for Time Greater than Allowed by Technical Specifications 05000336/LER-2022-001, Structural Integrity of Reactor Building Component Cooling Water Cracked Threaded Fitting Could Not Be Established Resulting in System Inoperable Longer than Allowed by Technical Specifications2022-03-18018 March 2022 Structural Integrity of Reactor Building Component Cooling Water Cracked Threaded Fitting Could Not Be Established Resulting in System Inoperable Longer than Allowed by Technical Specifications 05000336/LER-2021-002, Failed Check Valve Resulting in Unnalyzed and Operation Prohibited by Technical Specifications2022-01-0505 January 2022 Failed Check Valve Resulting in Unnalyzed and Operation Prohibited by Technical Specifications 05000336/LER-2021-001, Incorrectly Placed Spent Fuel Assemblies in Unit 2 Spent Fuel Pool2021-09-23023 September 2021 Incorrectly Placed Spent Fuel Assemblies in Unit 2 Spent Fuel Pool 05000423/LER-2020-005, Loss of Safety Function - Secondary Containment2020-11-19019 November 2020 Loss of Safety Function - Secondary Containment 05000423/LER-2020-002, 3, Automatic Reactor Trip Due to Main Generator Ground Fault2020-05-28028 May 2020 3, Automatic Reactor Trip Due to Main Generator Ground Fault 05000423/LER-2020-001, Technical Specification Allowed Outage Time Exceeded by Accident Monitoring Instrument2020-03-0505 March 2020 Technical Specification Allowed Outage Time Exceeded by Accident Monitoring Instrument 05000336/LER-2019-001, Manual Reactor Trip Due to Loss of the a Steam Generator Feed Pump2020-02-19019 February 2020 Manual Reactor Trip Due to Loss of the a Steam Generator Feed Pump 05000423/LER-2019-001, Regarding Plant Shutdown Required by Technical Specifications, Emergency Diesel Generator Exceeded Allowed Outage Time2020-02-13013 February 2020 Regarding Plant Shutdown Required by Technical Specifications, Emergency Diesel Generator Exceeded Allowed Outage Time 05000336/LER-2018-001, Regarding Loss of Both Trains of Control Room Emergency Ventilation Resulting in the Loss of Safety Function2018-12-19019 December 2018 Regarding Loss of Both Trains of Control Room Emergency Ventilation Resulting in the Loss of Safety Function 05000423/LER-2017-001, Regarding Loss of Safety Function - Secondary Containment2017-03-20020 March 2017 Regarding Loss of Safety Function - Secondary Containment 05000336/LER-2016-002, Regarding Manual Reactor Trip Due Loss of Two Circulating Water Pumps2016-09-20020 September 2016 Regarding Manual Reactor Trip Due Loss of Two Circulating Water Pumps 05000423/LER-2016-005, Technical Specification Required Shutdown and Manual Reactor Trip Due to Steam Generator Level Oscillation2016-08-0909 August 2016 Technical Specification Required Shutdown and Manual Reactor Trip Due to Steam Generator Level Oscillation 05000423/LER-2016-004, Manual Reactor Trip Due to Low Hydrogen Gas Pressure in Main Generator2016-07-13013 July 2016 Manual Reactor Trip Due to Low Hydrogen Gas Pressure in Main Generator 05000336/LER-2016-001, Turbine Driven Auxiliary Feedwater Pump Room HELB Door Left Open2016-06-27027 June 2016 Turbine Driven Auxiliary Feedwater Pump Room HELB Door Left Open 05000423/LER-2016-003, Regarding Loss of Safety Function-Supplementary Leak Collection and Release System2016-06-0808 June 2016 Regarding Loss of Safety Function-Supplementary Leak Collection and Release System 05000423/LER-2016-002, Regarding Feedwater Isolation Signal Defeated Due to Wiring Error2016-03-23023 March 2016 Regarding Feedwater Isolation Signal Defeated Due to Wiring Error 05000423/LER-2016-001, Regarding Automatic Reactor Trip on Reactor Coolant System Low Flow Due to Loss of B Reactor Coolant Pump2016-03-16016 March 2016 Regarding Automatic Reactor Trip on Reactor Coolant System Low Flow Due to Loss of B Reactor Coolant Pump 05000336/LER-2015-003, Regarding Valid Actuation of the Reactor Protection System2016-01-0707 January 2016 Regarding Valid Actuation of the Reactor Protection System 05000336/LER-2015-002, Regarding Degraded Emergency Core Cooling System Check Valve2015-08-10010 August 2015 Regarding Degraded Emergency Core Cooling System Check Valve 05000336/LER-2015-001, Regarding Historical Oil Leakage from C RBCCW Pump Bearings Challenged Meeting Mission Time2015-06-16016 June 2015 Regarding Historical Oil Leakage from C RBCCW Pump Bearings Challenged Meeting Mission Time 05000423/LER-2015-001, Regarding Unlatched Dual Train HELB Door Results in Potential Loss of Safety Function2015-04-20020 April 2015 Regarding Unlatched Dual Train HELB Door Results in Potential Loss of Safety Function 05000423/LER-2014-004, Regarding Unlatched Dual Train HELB Door Results in Potential Loss of Safety Function2015-02-0909 February 2015 Regarding Unlatched Dual Train HELB Door Results in Potential Loss of Safety Function 05000336/LER-2014-007, Regarding Completion of Plant Shutdown Required by Technical Specifications2014-09-24024 September 2014 Regarding Completion of Plant Shutdown Required by Technical Specifications 05000336/LER-2014-006, Regarding Millstone Power Station Dual Unit Reactor Trip on Loss of Offsite Power2014-07-24024 July 2014 Regarding Millstone Power Station Dual Unit Reactor Trip on Loss of Offsite Power 05000336/LER-2014-005, Regarding Train a Containment Spray Inoperable Due to Gas Voids2014-07-16016 July 2014 Regarding Train a Containment Spray Inoperable Due to Gas Voids 05000423/LER-2014-003, Regarding Turbine Driven Auxiliary Feedwater Pump Operability Impacted by Incorrect Bearing2014-06-30030 June 2014 Regarding Turbine Driven Auxiliary Feedwater Pump Operability Impacted by Incorrect Bearing 05000336/LER-2014-004, Regarding Foreign Material Found in a Motor Lead Rendered a Motor Driven Auxiliary Feedwater Pump Inoperable2014-06-0909 June 2014 Regarding Foreign Material Found in a Motor Lead Rendered a Motor Driven Auxiliary Feedwater Pump Inoperable 05000336/LER-2014-003, Regarding Loss of Safety Function Due to Inoperable Enclosure Building2014-06-0202 June 2014 Regarding Loss of Safety Function Due to Inoperable Enclosure Building 05000336/LER-2014-002, 2 Regarding DC Circuit Hot Shorts2014-05-0505 May 2014 2 Regarding DC Circuit Hot Shorts 05000423/LER-2014-002, Regarding DC Circuit Hot Shorts2014-05-0505 May 2014 Regarding DC Circuit Hot Shorts 05000336/LER-2014-001, Regarding Completion of Plant Shutdown Required by Technical Specifications2014-03-31031 March 2014 Regarding Completion of Plant Shutdown Required by Technical Specifications 05000423/LER-2014-001, Limiting Condition for Operation Exceeded Upon Approval of Enforcement Discretion2014-03-17017 March 2014 Limiting Condition for Operation Exceeded Upon Approval of Enforcement Discretion 05000423/LER-2013-009, Regarding Secondary Containment Boundary Breach Could Have Prevented Safety Function2014-01-15015 January 2014 Regarding Secondary Containment Boundary Breach Could Have Prevented Safety Function 05000336/LER-2013-004, Unit 2 Regarding Reactor Trip While Backwashing D Waterbox2013-12-19019 December 2013 Unit 2 Regarding Reactor Trip While Backwashing D Waterbox 2024-09-26
[Table view] |
LER-2008-001, Regarding Postulated Fire Scenario Results in Unanalyzed Condition - Pressurizer Overfill |
Event date: |
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Reporting criterion: |
10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition |
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4232008001R00 - NRC Website |
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text
Dominion Nuclear Connecticut, Inc.
Millstone Power Station Rope Ferry Road, Waterford, CT 06385 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 OCT 2 6 Serial No.
MPS Lic/ITGC Docket No.
License No.
2000 08-0593 RO 50-423 NPF-49 DOMINION NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 3 LICENSEE EVENT REPORT 2008-001-00, POSTULATED FIRE SCENARIO RESULTS IN UNANALYZED CONDITION - PRESSURIZER OVERFILL This letter forwards Licensee Event Report (LER) 2008-001-00, documenting a condition identified at Millstone Power Station Unit 3, on August 29, 2008. This LER is being submitted pursuant to 10 CFR 50.73(a)(2)(ii)(B).
If you have any questions or require additional information, please contact Mr. William D. Bartron at (860) 444-4301.
Sincerely, A.
VJ.J rdean, Jr.
Site Vice President - Millstone
Serial No. 08-0593 Licensee Event Report 2008-001-00 Page 2 of 2 Attachments:
1 Commitments made in this letter: None.
cc:
U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406-1415 Ms. C. J. Sanders - Project Manager U.S. Nuclear Regulatory Commission, Mail Stop 08 B3 One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station
Serial No. 08-0593 Licensee Event Report 2008-001-00 POSTULATED FIRE SCENARIO RESULTS IN UNANALYZED CONDITION PRESSURIZER OVERFILL MILLSTONE POWER STATION UNIT 3 DOMINION NUCLEAR CONNECTICUT, INC. (DNC)
Abstract
On August 29, 2008 at 1007 while operating at 100% power, Millstone Power Station Unit 3 identified a potential vulnerability in the fire safe shutdown strategy which, under certain fire conditions, may challenge the ability to meet the performance criteria of the approved fire protection program. It is postulated that under certain fire conditions affecting the control room, the ability to maintain pressurizer level within the indicated range (high) may be challenged and lead to water relief through the pressurizer safety valves. The pressurizer safety valves are not qualified for water relief.
The apparent cause of this condition is a deficiency in the original fire protection evaluations to meet the requirements of Branch Technical Position (BTP) CMEB9.5-1 (NUREG-0800) as documented in the Millstone Unit 3 Fire Protection Evaluation Shutdown System Availability Report of 1985 (BTP Compliance Report). A modification is being implemented that will prevent this condition during plant power operations.
Additional corrective actions are being addressed in accordance with the station's corrective action program.
This condition has had no actual safety consequences as no fire has occurred to challenge the circuits in question. This event involves a postulated fire scenario and subsequent potential failure. This condition had no direct impact on the health and safety of the public or plant personnel. The event does involve an unanalyzed condition related to safe shutdown capability. This condition is being reported under 10 CFR 50.73(a)(2)(ii)(B),
"Any event or condition that resulted in the nuclear power plant being in an unanalyzed condition that significantly degraded Plant safety."
(If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A) (17) could result in extensive damage. This is particularly the case for the control room (which is continuously staffed),
instrument rack room and cable spreading room in which the design features include multiple fire suppression options and no high voltage circuits or other significant ignition sources.
This condition had no direct impact on the health and safety of the public or plant personnel. This condition has had no actual safety consequences as no fire has ever occurred at MPS3 to challenge the circuits in question. Furthermore, a review of control room events in the Fire Events Database (Reference NUREG/CR-6850 Appendix L) reveals that none of the control room fires that had occurred in the industry affected components much beyond the point of ignition. In all cases, the fire was discovered by control room personnel and extinguished using hand-held extinguishers. Since the control room is occupied at all times, it is expected that the likelihood of a fire affecting a large number of items inside the main control board is low. It is expected that a detailed fire PRA analysis would show that a fire of this type is expected to contribute less than 1 E-6/year to core damage frequency (CDF) based on the low frequency of a fire in the control room with the specific qualities that would lead to nearly immediate evacuation and adverse system operation.
The event does involve an unanalyzed condition related to safe shutdown capability and operation.
- 4.
Corrective Actions
Compensatory actions were implemented that enhance the defense in depth philosophy to prevent, detect and rapidly extinguish fires to minimize the likelihood of a large scale fire affecting the control room. These include additional controls of combustible materials, hourly fire watches and increased monitoring of fire detection and suppression systems for the affected fire areas.
A modification is being implemented that will prevent pressurizer overfill from fire-induced failures during plant power operations. Beginning in Cycle 13 (scheduled for November 2008), a permissive on Low Pressurizer Pressure is being added to the reactor coolant system cold leg injection valves. This modification permits injection to the RCS from the charging pumps upon receipt of a safety injection signal only when the reactor coolant system pressure has dropped below the low pressurizer pressure setpoint.
Further evaluations are under way to ensure that the full scope of any other postulated fire scenarios that could result in pressurizer overfill have been identified. The compensatory actions will remain in place until that review is complete.
Additional corrective actions are being addressed in accordance with the station's corrective action program.
- 5.
Previous Occurrences
No previous similar events/conditions were identified.
Energy Industry Identification System (EIIS) codes are identified in the text as [XX].
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05000423/LER-2008-001, Regarding Postulated Fire Scenario Results in Unanalyzed Condition - Pressurizer Overfill | Regarding Postulated Fire Scenario Results in Unanalyzed Condition - Pressurizer Overfill | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition | 05000336/LER-2008-001, Re Failure of Eight Main Steam Safety Valves to Lift within the Acceptance Criteria | Re Failure of Eight Main Steam Safety Valves to Lift within the Acceptance Criteria | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(ix)(A), Prevented Safety Function in Multiple System | 05000336/LER-2008-002, Regarding Unplanned LCO Entry - Three Charging Pumps Aligned for Injection with the Reactor Coolant System Temperature Less than 300 Degrees F | Regarding Unplanned LCO Entry - Three Charging Pumps Aligned for Injection with the Reactor Coolant System Temperature Less than 300 Degrees F | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000423/LER-2008-002, Unit 3 Failure of Four Main Steam Safety Valves to Lift within the Acceptance Criteria | Unit 3 Failure of Four Main Steam Safety Valves to Lift within the Acceptance Criteria | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000423/LER-2008-003, Automatic Reactor Trip During Shutdown for Refueling Outage 3R12 | Automatic Reactor Trip During Shutdown for Refueling Outage 3R12 | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000336/LER-2008-003, Millstone. Unit 2, Regarding Failed Pilot Wire Causes Reactor Trip | Millstone. Unit 2, Regarding Failed Pilot Wire Causes Reactor Trip | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000423/LER-2008-004, Gas Void Discovered in the Emergency Core Cooling System Suction Line | Gas Void Discovered in the Emergency Core Cooling System Suction Line | 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000336/LER-2008-004, Reactor Trip Due to a Loss of Normal Power Event | Reactor Trip Due to a Loss of Normal Power Event | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000423/LER-2008-005, For Millstone Power Station, Unit 3 Regarding Containment Penetration Not Fully Closed During Fuel Movement | For Millstone Power Station, Unit 3 Regarding Containment Penetration Not Fully Closed During Fuel Movement | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000336/LER-2008-005, Regarding Feedwater Heater Level Oscillation and Manual Reactor Trip | Regarding Feedwater Heater Level Oscillation and Manual Reactor Trip | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000423/LER-2008-006, For Millstone, Unit 3, Regarding Turbine-Driven Auxiliary Feedwater Pump Steam Trap Isolation Valves Found Closed | For Millstone, Unit 3, Regarding Turbine-Driven Auxiliary Feedwater Pump Steam Trap Isolation Valves Found Closed | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(ix)(A), Prevented Safety Function in Multiple System |
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