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Category:Letter
MONTHYEAR05000237/LER-2024-001, Containment Cooling Service Water Valve Failure Resulted in a Condition Prohibited by Technical Specifications and Loss of Safety Function2025-01-27027 January 2025 Containment Cooling Service Water Valve Failure Resulted in a Condition Prohibited by Technical Specifications and Loss of Safety Function ML24351A1452025-01-23023 January 2025 Request to Replace Previously Submitted Documents and Withhold Information from Public Disclosure 05000249/LER-2024-002, Low Pressure Coolant Injection Pump Suction Relief Valve Inoperable as a Primary Containment Isolated Valve Resulted in a Condition Prohibited by Technical Specifications2025-01-21021 January 2025 Low Pressure Coolant Injection Pump Suction Relief Valve Inoperable as a Primary Containment Isolated Valve Resulted in a Condition Prohibited by Technical Specifications ML25017A2302025-01-17017 January 2025 Information Request to Support Upcoming Problem Identification and Resolution Inspection at Dresden Nuclear Power Station, Units 2 & 3 ML24353A1372025-01-15015 January 2025 Proprietary Determination Constellation Energy Generation, LLC 2024 Deferred Premiums IR 05000010/20240012024-12-31031 December 2024 NRC Inspection Report No. 05000010/2024001 ML24344A2742024-12-19019 December 2024 Alternative Request to Use American Society of Mechanical Engineers Boiler and Pressure Vessel Code Case OMN-32 RS-24-135, Submittal of Preliminary Decommissioning Cost Estimate and Irradiated Fuel Management Plan2024-12-18018 December 2024 Submittal of Preliminary Decommissioning Cost Estimate and Irradiated Fuel Management Plan ML24352A2072024-12-17017 December 2024 Notification of NRC Fire Protection Team Inspection Request for Information ML24331A2592024-11-27027 November 2024 Reassignment of the U.S. Nuclear Regulatory Commission Branch Chief in the Division of Operating Reactor Licensing for Plant Licensing Branch III ML24324A3202024-11-19019 November 2024 Letter from R. Mangum, Achp Regarding DNPS Subsequent License Renewal Environmental Review ML24323A0792024-11-15015 November 2024 Transmittal of Dresden, Units 2 and 3, Core Operating Limits Report Cycle 29 ML24317A1432024-11-0404 November 2024 Constellation Energy Generation, LLC, 2024 Annual Report - Guarantees of Payment of Deferred Premiums ML24303A0712024-11-0404 November 2024 Letter to K. Meshigaud, Chairperson Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A1342024-11-0101 November 2024 Letter to T. Carnes, Chairperson Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A0692024-11-0101 November 2024 Letter to J.A. Crawford, Chairman Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A0202024-11-0101 November 2024 Letter to C. Chavers, Chairwoman Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A1442024-11-0101 November 2024 Letter to V. Kitcheyna, Chairwoman Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A0132024-11-0101 November 2024 Letter to B. Barnes, Chairman Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A0642024-11-0101 November 2024 Letter to J. Rupnick, Chairman Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A1172024-11-0101 November 2024 Letter to R. Yob, Chairman Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A0272024-11-0101 November 2024 Letter to D. Rios, Chairperson Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A0512024-11-0101 November 2024 Letter to J. Barrett, Chairman Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A1422024-11-0101 November 2024 Letter to V. Jefferson, Chairman Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A0472024-11-0101 November 2024 Letter to G. Cheatham, Chairwoman Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A0602024-11-0101 November 2024 Letter to J. R. Shotton, Chairman Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A0552024-11-0101 November 2024 Letter to J. Keys, Chairman Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A0492024-11-0101 November 2024 Letter G. Kakkak, Chairwoman Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A0992024-11-0101 November 2024 Lett to R. Carter, Principal Chief Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A1352024-11-0101 November 2024 Letter to T. Rhodd, Chairperson Request to Initiate Section 106 Consultation for SLR of DNP Station RS-24-104, Nuclear Radiological Emergency Plan Document Revision2024-11-0101 November 2024 Nuclear Radiological Emergency Plan Document Revision IR 05000237/20254012024-11-0101 November 2024 Information Request for the Cyber Security Baseline Inspection, Notification to Perform Inspection 05000237/2025401 05000249/2025401 ML24291A0252024-11-0101 November 2024 Letter to R. Blanchard Tribal Chairman Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A0892024-11-0101 November 2024 Letter to M. J. Wesaw, Chair Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A0152024-11-0101 November 2024 Letter to C. Harper, Chief Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A1462024-11-0101 November 2024 Letter to W. Gravelle, Chairperson Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A0172024-11-0101 November 2024 Letter to B. Peters, Chairman Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A0432024-11-0101 November 2024 Letter to E. Elizondo, Sr. Chairman Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A1102024-11-0101 November 2024 Letter to R. Gasco, Chairperson Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A0532024-11-0101 November 2024 Letter to J. Greendeer, President Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A0302024-11-0101 November 2024 Letter to D.G. Lankford, Chief Request to Initiate Section 106 Consultation for SLR of DNP Station ML24303A0242024-11-0101 November 2024 Letter to D. Kaskaske, Chairman Request to Initiate Section 106 Consultation for SLR of DNP Station ML24291A0202024-10-31031 October 2024 NRC Letter to J. Loichinger Achp Request for Comments Concerning the Environmental Review of DNPS Units 2 and 3 Subsequent License Renewal Application RS-24-126, Request to Replace Formerly Submitted Documents Available in the Agency Documents Access and Management System (ADAMS) with Documents Redacted in Accordance with 10 CFR 2.390(b)(4)2024-10-31031 October 2024 Request to Replace Formerly Submitted Documents Available in the Agency Documents Access and Management System (ADAMS) with Documents Redacted in Accordance with 10 CFR 2.390(b)(4) ML24291A0272024-10-31031 October 2024 NRC Letter to C. Mayer Illinois SHPO Request to Initiate Section 106 Consultation for Subsequent License Renewal of Units 2 and 3 IR 05000237/20240032024-10-29029 October 2024 Integrated Inspection Report 05000237/2024003 and 05000249/2024003 RS-24-103, Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors2024-10-21021 October 2024 Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors RS-24-102, Supplement to License Amendment Request to Revise Technical Specifications to Adopt Risk Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b, and TSTF-5912024-10-21021 October 2024 Supplement to License Amendment Request to Revise Technical Specifications to Adopt Risk Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b, and TSTF-591 RS-24-080, Request to Replace Formerly Submitted Documents Available in the Agency Documents Access and Management System (ADAMS) with Documents Redacted in .2024-10-16016 October 2024 Request to Replace Formerly Submitted Documents Available in the Agency Documents Access and Management System (ADAMS) with Documents Redacted in . RS-24-093, Response to Request for Additional Information - Alternative Request to Utilize Code Case OMN-32, Alternative Requirements for Range and Accuracy of Pressure, Flow, and Differential Pressure Instruments Used in Pump Tests2024-10-10010 October 2024 Response to Request for Additional Information - Alternative Request to Utilize Code Case OMN-32, Alternative Requirements for Range and Accuracy of Pressure, Flow, and Differential Pressure Instruments Used in Pump Tests 2025-01-27
[Table view] Category:Licensee Event Report (LER)
MONTHYEAR05000237/LER-2024-001, Containment Cooling Service Water Valve Failure Resulted in a Condition Prohibited by Technical Specifications and Loss of Safety Function2025-01-27027 January 2025 Containment Cooling Service Water Valve Failure Resulted in a Condition Prohibited by Technical Specifications and Loss of Safety Function 05000249/LER-2024-002, Low Pressure Coolant Injection Pump Suction Relief Valve Inoperable as a Primary Containment Isolated Valve Resulted in a Condition Prohibited by Technical Specifications2025-01-21021 January 2025 Low Pressure Coolant Injection Pump Suction Relief Valve Inoperable as a Primary Containment Isolated Valve Resulted in a Condition Prohibited by Technical Specifications 05000237/LER-2023-001, HPCI Inoperable Due to Air Void Accumulation2024-01-19019 January 2024 HPCI Inoperable Due to Air Void Accumulation 05000237/LER-2022-002-01, Ultimate Heat Sink Declared Inoperable Due to River Grass Accumulation2022-10-28028 October 2022 Ultimate Heat Sink Declared Inoperable Due to River Grass Accumulation 05000237/LER-2022-001-01, Reactor Scram Due to Turbine Trip on High Reactor Water Level Caused by Feedwater Regulating Valve Failure2022-10-28028 October 2022 Reactor Scram Due to Turbine Trip on High Reactor Water Level Caused by Feedwater Regulating Valve Failure 05000237/LER-2022-002, Ultimate Heat Sink Declared Inoperable Due to River Grass Accumulation2022-09-27027 September 2022 Ultimate Heat Sink Declared Inoperable Due to River Grass Accumulation 05000237/LER-2022-001, Reactor Scram Due to Turbine Trip on High Reactor Water Level Caused by Feedwater Regulating Valve Failure2022-09-0909 September 2022 Reactor Scram Due to Turbine Trip on High Reactor Water Level Caused by Feedwater Regulating Valve Failure 05000249/LER-2021-001-01, Reactor Scram Due to Main Power Transformer Failure2022-06-14014 June 2022 Reactor Scram Due to Main Power Transformer Failure ML20135G7442020-05-14014 May 2020 Final ASP Analysis - Dresden 2 (LER 237-90-006) 05000249/LER-2019-001, Degraded Differential Pressure Indicating Switch in the LPCI Loop Select Logic Caused by Water Damage Results in a Condition Prohibited by Technical Specifications2019-11-19019 November 2019 Degraded Differential Pressure Indicating Switch in the LPCI Loop Select Logic Caused by Water Damage Results in a Condition Prohibited by Technical Specifications 05000237/LER-2019-002, Scram Due to Main Turbine Low Oil Pressure Trip2019-07-0202 July 2019 Scram Due to Main Turbine Low Oil Pressure Trip 05000237/LER-2019-001, Secondary Containment Differential Pressure Exceeded Technical Specification Due to Excess Ventilation Supply Flow2019-03-29029 March 2019 Secondary Containment Differential Pressure Exceeded Technical Specification Due to Excess Ventilation Supply Flow 05000237/LER-2017-002-01, Regarding Primary Containment Inboard and Outboard Feedwater Isolation Valves Exceed Leakage2018-02-15015 February 2018 Regarding Primary Containment Inboard and Outboard Feedwater Isolation Valves Exceed Leakage 05000237/LER-1917-002, Regarding Primary Containment Inboard and Outboard Feedwater Isolation Valves Exceed Leakage Limits2018-01-0202 January 2018 Regarding Primary Containment Inboard and Outboard Feedwater Isolation Valves Exceed Leakage Limits 05000249/LER-1917-001, Regarding Standby Liquid Control System Inoperable Due to a Manufacturing Defect Causing a Piping Leak2017-11-10010 November 2017 Regarding Standby Liquid Control System Inoperable Due to a Manufacturing Defect Causing a Piping Leak 05000237/LER-1977-050, /03L-0 for Dresden, Unit 2 Re Local Leak Rate Test of Drywell Personnel Air Lock During Refueling2017-11-0303 November 2017 /03L-0 for Dresden, Unit 2 Re Local Leak Rate Test of Drywell Personnel Air Lock During Refueling 05000249/LER-1977-040, /03L-0 for Dresden 3 Regarding the Circuit Breaker for Service Water Makeup Valve MO-3-4102 to the Isolation Condenser Found in Off Position2017-10-21021 October 2017 /03L-0 for Dresden 3 Regarding the Circuit Breaker for Service Water Makeup Valve MO-3-4102 to the Isolation Condenser Found in Off Position 05000237/LER-1978-028, /01X-1 for Dresden, Units 2 and 3 Re NRC Request for Immediate Actions to Be Taken to Mitigate the Potential for a Spurious Closure of a Recirculation Loop Suction Valve with a LOCA Occurring Between the Loop Discharge and Suct2017-08-28028 August 2017 /01X-1 for Dresden, Units 2 and 3 Re NRC Request for Immediate Actions to Be Taken to Mitigate the Potential for a Spurious Closure of a Recirculation Loop Suction Valve with a LOCA Occurring Between the Loop Discharge and Suction Valves 05000237/LER-1916-003, Cancellation of Licensee Event Report 237/2016-003-00, Control Room Emergency Ventilation System Charcoal Filter Bank Failure to Meet the Methyl Iodide Penetration Acceptance Criteria2017-05-26026 May 2017 Cancellation of Licensee Event Report 237/2016-003-00, Control Room Emergency Ventilation System Charcoal Filter Bank Failure to Meet the Methyl Iodide Penetration Acceptance Criteria 05000237/LER-2016-004, Regarding Reactor Building Differential Pressure Less than Technical Specification Requirement2017-01-0909 January 2017 Regarding Reactor Building Differential Pressure Less than Technical Specification Requirement 05000237/LER-2016-003, Regarding Control Room Emergency Ventilation System Charcoal Filter Bank Failure to Meet the Methyl Iodide Penetration Acceptance Criteria2016-11-18018 November 2016 Regarding Control Room Emergency Ventilation System Charcoal Filter Bank Failure to Meet the Methyl Iodide Penetration Acceptance Criteria 05000249/LER-2016-001, Regarding Alert Declared from Unit 3 HPCI Auxiliary Oil Pump Motor Fire2016-08-25025 August 2016 Regarding Alert Declared from Unit 3 HPCI Auxiliary Oil Pump Motor Fire 05000237/LER-2016-002, Regarding HPCI Inlet Steam Drain Pot Piping Leak Resulting in HPCI Inoperability2016-07-15015 July 2016 Regarding HPCI Inlet Steam Drain Pot Piping Leak Resulting in HPCI Inoperability 05000237/LER-2016-001, Regarding Secondary Containment Differential Pressure Transient2016-04-0808 April 2016 Regarding Secondary Containment Differential Pressure Transient 05000237/LER-2015-005-02, Regarding Unit 2 HPCI Motor Gear Unit Would Not Return to Full Flow During Testing2016-03-31031 March 2016 Regarding Unit 2 HPCI Motor Gear Unit Would Not Return to Full Flow During Testing 05000237/LER-2015-005-01, Regarding HPCI Motor Gear Unit Would Not Return to Full Flow During Testing2016-02-25025 February 2016 Regarding HPCI Motor Gear Unit Would Not Return to Full Flow During Testing 05000237/LER-2015-003, Regarding Turbine Building to Reactor Building Interlock Doors Open Simultaneously2015-10-30030 October 2015 Regarding Turbine Building to Reactor Building Interlock Doors Open Simultaneously 05000237/LER-2015-005, Regarding HPCI Motor Gear Unit Would Not Return to Full Flow During Testing2015-10-30030 October 2015 Regarding HPCI Motor Gear Unit Would Not Return to Full Flow During Testing 05000249/LER-2015-001, Regarding Main Steam Line Flow Switches Found Outside Tech Spec Allowed Value2015-10-29029 October 2015 Regarding Main Steam Line Flow Switches Found Outside Tech Spec Allowed Value 05000237/LER-2015-002, Regarding 2C ERV Failed to Actuate During Extent of Condition Testing2015-04-0303 April 2015 Regarding 2C ERV Failed to Actuate During Extent of Condition Testing 05000237/LER-2015-001, Regarding Unit 2 Scram Due to Feedwater Level Control Issues2015-03-0606 March 2015 Regarding Unit 2 Scram Due to Feedwater Level Control Issues 05000249/LER-2014-001, Regarding Electromatic Relief Valve Failing to Actuate During Surveillance Testing2015-01-0505 January 2015 Regarding Electromatic Relief Valve Failing to Actuate During Surveillance Testing 05000237/LER-2014-003, Regarding Reactor Scram During Automatic Voltage Regulator Channel Transfer2014-06-0606 June 2014 Regarding Reactor Scram During Automatic Voltage Regulator Channel Transfer 05000237/LER-2014-002, Regarding Reactor Scram Due to Main Power Transformer Failure2014-06-0606 June 2014 Regarding Reactor Scram Due to Main Power Transformer Failure 05000237/LER-2014-001, Regarding Secondary Containment Inoperable Due to Two Interlock Doors Being Open Simultaneously2014-05-27027 May 2014 Regarding Secondary Containment Inoperable Due to Two Interlock Doors Being Open Simultaneously 05000237/LER-2013-009, Regarding HPCI Failed to Achieve Rated Flow Due to Failure of Stop Valve to Open2014-01-29029 January 2014 Regarding HPCI Failed to Achieve Rated Flow Due to Failure of Stop Valve to Open 05000249/LER-2013-001, Regarding Secondary Containment Inoperable Due to Two Interlock Doors Being Open Simultaneously2014-01-27027 January 2014 Regarding Secondary Containment Inoperable Due to Two Interlock Doors Being Open Simultaneously 05000237/LER-2013-008, Regarding Leak Identified on a Relief Valve During Pressure Test Resulting in a Degraded Principal Safety Barrier2014-01-24024 January 2014 Regarding Leak Identified on a Relief Valve During Pressure Test Resulting in a Degraded Principal Safety Barrier 05000237/LER-2013-007, Regarding Secondary Containment Inoperable Due to Two Interlock Doors Being Open Simultaneously2014-01-15015 January 2014 Regarding Secondary Containment Inoperable Due to Two Interlock Doors Being Open Simultaneously 05000237/LER-2013-005, Regarding Primary Containment Inboard and Outboard Feed Water Isolation Valves Exceed Leakage Limits2014-01-13013 January 2014 Regarding Primary Containment Inboard and Outboard Feed Water Isolation Valves Exceed Leakage Limits 05000237/LER-2013-006, Dressden Nuclear Power Station, Unit 2, Regarding LPCI Swing Bus Auto Transfer Did Not Transfer as Expected2014-01-13013 January 2014 Dressden Nuclear Power Station, Unit 2, Regarding LPCI Swing Bus Auto Transfer Did Not Transfer as Expected 05000237/LER-2013-004, Regarding Secondary Containment Inoperable Due to Two Interlock Doors Being Open Simultaneously2014-01-0606 January 2014 Regarding Secondary Containment Inoperable Due to Two Interlock Doors Being Open Simultaneously 05000237/LER-2013-003, Regarding Secondary Containment Inoperable Due to Two Interlock Doors Being Open Simultaneously2013-11-22022 November 2013 Regarding Secondary Containment Inoperable Due to Two Interlock Doors Being Open Simultaneously 05000237/LER-2013-002, Movement of Control Rods with Control Rod Block Monitor Inoperable2013-09-27027 September 2013 Movement of Control Rods with Control Rod Block Monitor Inoperable 05000237/LER-2013-001, Secondary Containment Inoperable Due to Two Interlock Doors Being Open Simultaneously2013-08-23023 August 2013 Secondary Containment Inoperable Due to Two Interlock Doors Being Open Simultaneously 05000237/LER-2011-005-01, For Dresden, Unit 2, Regarding Standby Liquid Control Explosive Valve Failure2012-12-18018 December 2012 For Dresden, Unit 2, Regarding Standby Liquid Control Explosive Valve Failure 05000237/LER-2012-001, Regarding One Division of APRM Neutron Flux-High Channels Inoperable as a Result of Power Maneuver2012-12-0606 December 2012 Regarding One Division of APRM Neutron Flux-High Channels Inoperable as a Result of Power Maneuver 05000249/LER-2012-001, Regarding Unexpected Isolation of the Isolation Condenser Due to Test Switch Failure2012-09-10010 September 2012 Regarding Unexpected Isolation of the Isolation Condenser Due to Test Switch Failure 05000237/LER-2012-002, Regarding Inlet Steam Drain Pot Drain Line Leaks Result in HPCI Inoperabilities2012-07-23023 July 2012 Regarding Inlet Steam Drain Pot Drain Line Leaks Result in HPCI Inoperabilities 05000237/LER-2011-003, Regarding MSIV Closure Times Outside of Technical Specifications Limits2011-12-16016 December 2011 Regarding MSIV Closure Times Outside of Technical Specifications Limits 2025-01-27
[Table view] |
LER-2003-001, Regarding Drywell Radiation Monitor Detector Not Fully Inserted |
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ExekI n.
Exelon Generation Dresden Generating Station 6500 North Dresden Road Morris, IL 60450-9765 Tel 815-942-2920 www.exeloncorp.com Nuclear 10 CFR 50.73 October 27, 2003 RHLTR: #03-0070 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Unit 3 Facility Operating License No. DRP-25 NRC Docket No. 50-249
Subject:
Licensee Event Report 2003-001-00, "Drywell Radiation Monitor Detector Not Fully Inserted" Enclosed is Licensee Event Report 2003-001-00 "Drywell Radiation Monitor Detector Not Fully Inserted," for the Dresden Nuclear Power Station Unit 3. This event is being reported in accordance with 10 CFR 50.73(a)(2)(i)(B), "Any operation or condition which was prohibited by the plant's Technical Specifications."
Should you have any questions concerning this report, please contact Jeff Hansen, Regulatory Assurance Manager, at (815) 416-2800.
Respectfully, k/u R. J. Hovey Site Vice President Dresden Nuclear Power Station Enclosure cc:
Regional Administrator - NRC Region III NRC Senior Resident Inspector - Dresden Nuclear Power Station IJ
I
Abstract
On August 27, 2003, at approximately 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br /> (CDT), an Instrument Maintenance Department Technician confirmed that Unit 3 Drywell Radiation Monitor detector 3B was approximately 23.5 inches from full insertion. The functions of the Drywell Radiation Monitors are to provide a primary containment isolation signal due to high radiation per Technical Specification (TS) 3.3.6.1, 'Primary Containment Isolation Instrumentation," and post accident radiation monitoring capability to control room operators during potential accident situations per TS 3.3.3.1, 'Post Accident Monitoring (PAM)
Instrumentation." Engineering performed an evaluation and determined that the Unit 3 detector 3B could not perform its TS functions in the as-found partially inserted condition. This condition had existed since October 23, 2002.
The investigation identified the root cause as inadequate procedural direction in the placement of the detector in its penetration. The corrective action to prevent recurrence was to revise Dresden procedure DIS-1700-16, 'Drywell High Radiation Monitor Group 2 Isolation Functional and Calibration Tests," to clarify that the detector be fully inserted into the penetration until the detector is in contact with the inner surface of the penetration.U.S. NUCLEAR REGULATORY APPROVED BY OMB NO. 315040104 COMMISSION EXPIRES 07/3112004 (7-2001)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
FACILITY NAME (1)
DOCKET NUMBER (2)
LER NUMBER (6)
PAGE (3)
YEAR SEQUENTIAL REVISION Dresden Nuclear Power Station Unit 3 05000249 NUMBER NUMBER 2003 001 00 2 of 4 (If more space is required, use additional copies of NRC Form 366AX17)
A.
Plant Conditions Prior to Event:
Unit: 03 Event Date: 10-23-2002 Event Time: 0800 CDT Reactor Mode: 4 Mode Name: Cold Shutdown Power Level: 0 percent Reactor Coolant System Pressure: 0 psig B.
Description of Event
This event is being reported in accordance with 10 CFR 50.73(a)(2)(i)(B), 'Any operation or condition which was prohibited by the plant's Technical Specifications."
On August 22, 2003 an Instrument Maintenance Department Supervisor and an NRC inspector walked down the two Unit 2 (RIS 2-2419A, RIS 2-2419B) and two Unit 3 (RIS 3-2419A, RIS 3-2419B) Drywell Radiation Monitor detector penetration locations. This walk down was at the request of the NRC inspector. During the walk down the procedure direction for detector insertion into the penetration was discussed but an inspection of the insertion depth of the detectors into their penetrations was not performed.
On August 26, 2003 a Component Maintenance Optimization Instrumentation and Control Specialist performed a visual verification of Drywell Radiation Monitor detector insertion depth into each penetration. The two Unit 2 detectors and one Unit 3 detector (RIS 3-2419A) were determined to be correctly inserted into their penetrations.
The specialist determined the insertion of the Unit 3 detector RIS 3-2419B (3B) required verification. On August 27, 2003 at approximately 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br /> (CDT), an Instrument Maintenance Department Technician confirmed that Unit 3 Drywell Radiation Monitor detector 3B was approximately 23.5 inches from full insertion. The technician inserted the detector fully into its penetration.
On August 25, 2003, an internal company communication, "Exelon Nuclear Event Report (NER) QC-03-056,
'Drywell Radiation Detector Found Not Fully Inserted into Drywell Penetration Location,"' was issued which described a similar event that occurred at Quad Cities Nuclear Power Station on July 14, 2003. The Drywell Radiation Monitor at Quad Cities Nuclear Power Station was evaluated for the as-found partial insertion condition and was determined to be operable. The NER was emailed to Exelon personnel in another internal company communication, "Daily Industry Events Reports," at 1627 (CDT) on August 27, 2003.
The functions of the Drywell Radiation Monitors are to provide a primary containment isolation signal due to high radiation per Technical Specification 3.3.6.1, "Primary Containment Isolation Instrumentation," and post accident radiation monitoring capability to control room operators during potential accident situations per TS 3.3.3.1, "Post Accident Monitoring (PAM) Instrumentation." Engineering performed an evaluation and determined that the Unit 3 detector 3B could not perform its TS functions in the as-found partially inserted condition. This condition has existed since October 23, 2002. Therefore this condition is reportable per 10 CFR 50.73(a)(2)(i)(B),
C.
Cause of Event
The root cause of the partial insertion of the Unit 3 Drywell Radiation Monitor detector 3B was inadequate procedure direction.U.S. NUCLEAR REGULATORY APPROVED BYOMB NO.315040104 COMMISSION EXPIRES 0713112004 (7-2001)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
FACILITY NAME (1)
DOCKET NUMBER (2)
LER NUMBER (6)
PAGE (3)
YEAR SEQUENTIAL REVISION Dresden Nuclear Power Station Unit 3 05000249 NUMBER NUMBER 2003 001 00 3 of 4 (If more space is required, use additional copies of NRC Form 366AX17)
Procedure DIS-1700-16, 'Drywell High Radiation Monitor Group 2 Isolation Functional and Calibration Tests," is used to calibrate and functionally test the Drywell Radiation Monitoring instrumentation. During the performance of the procedure, the Drywell High Radiation Monitor detector is removed from and reinserted into its penetration.
The Unit 3 detector 3B was last calibrated during a refueling outage on October 23, 2002. The detector penetrations all have different lengths and there were no specific procedural instructions that the detector had to be left in the fully inserted position for proper detector operation. This procedural direction has existed in procedure DIS-1700-16 since the early 1980s. Additionally, a review of the TS Bases, Updated Final Safety Analysis Report (UFSAR), vendor information and the applicable set point calculation did not reveal any specified requirement for the insertion depth of the detector in the penetration.
D.
Safety Analysis
The functions of the Drywell Radiation Monitors are to provide a primary containment isolation signal due to high radiation and post accident radiation monitoring capability to control room operators during potential accident situations.
Engineering performed an assessment which determined that the as-found partially inserted condition of the Unit 3 detector 3B caused the Drywell Radiation Monitor 3B to indicate approximately 30 percent of the estimated indication with the detector fully inserted. This condition was not discovered using channel checks during plant operation as the detectors are exposed to a relatively low radiation field and minor differences in detector readings are expected due to detector sensitivities and the physical location of the detector penetration to the radiation sources. The detector's indicators in the control room had a range from 1 to 10E+8 R/Hr. and the readings from the four detectors during plant operation in August 2003 were 1.7 R/Hr., 2.5 RIHr., 2.7 R/Hr. and 5.0 RIHr. with detector 3B reading 1.7 R/Hr.
The as-found partially inserted condition of detector 3B would have resulted in detector 3B being unable to perform its primary containment isolation function at the required TS 3.3.6.1 value. TS 3.3.6.1 specifies an Allowable Value of 77 R/Hr. for the primary containment isolation signal and it is estimated that the primary containment isolation signal would not have occurred until approximately 100 to 130 R/Hr. The primary containment isolation function is established to ensure that fission products would be contained in the unlikely event of high drywell radiation without the expected low reactor vessel level or high drywell pressure. The primary containment isolation function is not credited in any accident or transient analysis in the UFSAR.
Additionally, the as-found partially inserted condition of detector 3B would have resulted in detector 3B being unable to perform as expected in a post accident situation as required by TS 3.3.3.1. The Drywell Radiation Monitors would be used by control room operating staff to perform the diagnosis specified in the Emergency Operating Procedures (EOPs). An engineering assessment of detector 3B determined that although the Unit 3 Drywell Radiation Monitors were reading within a couple of RIHr. of each other during normal plant operation, during a postulated post accident situation detector 3B would be tracking the relative rise in the radiation level but indicating a much lower total radiation level than the other Unit 3 detector. Based on the expected plant conditions in a post accident situation and engineering judgment that conservative decision-making would be used, theU.S. NUCLEAR REGULATORY APPROVED BY OMB NO. 31504104 COMMISSION EXPIRES 07/31/2004 (7-2001)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the Information collection.
FACILITY NAME (1)
DOCKET NUMBER (2)
LER NUMBER (6)
PAGE (3)
YEAR SEQUENTIAL REVISION Dresden Nuclear Power Station Unit 3 05000249 NUMBER NUMBER 2003 001 00 4 of 4 (If more space is required, use additional copies of NRC Form 366A)(17) information available from both detectors would have resulted in the expected post accident diagnosis of high radiation in the drywell.
The as-found partially inserted condition of detector 3B did not affect the assumptions contained in UFSAR accident and transient analysis and the expected post accident diagnosis required by the EOPs would not have been adversely affected by the as-found partially inserted condition of detector 3B. Therefore, the consequences of this event had minimal impact on the health and safety of the public and reactor safety.
E.
Corrective Actions
The two Unit 2 Drywell Radiation Monitor detectors and one Unit 3 detector were determined to be correctly inserted into their penetrations on August 26, 2003.
Unit 3 Drywell Radiation Monitor detector 3B was fully inserted into its penetration on August 27, 2003.
Dresden Procedure DIS-1600-16 was revised to require the detector to be fully inserted into the penetration until the detector is in contact with inner surface of the penetration.
An extent of condition review of other procedures that control the installation of other radiation detectors at Dresden Nuclear Power Station revealed the need to verify the installation of the Fuel Pool Radiation Monitor detectors. A Component Maintenance Optimization Specialist performed an inspection of the installation of the detectors on September 19, 2003 and confirmed that they were all correctly installed.
Dresden procedures for the Fuel Pool Radiation Monitor detectors, DIS-1700-15, 'Fuel Pool Channel A and Channel B Area Radiation Monitor Channel Calibration Test" and DIS-1770-18, 'Fuel Pool Channel A and Channel B Area Radiation Monitor Channel Functional Test," have been revised.
F.
Previous Occurrences
A review of recent Dresden Nuclear Power Station Licensee Event Reports (LERs) identified the following events that were associated with inadequate procedural direction.
LER 2002-005, Unit 2 - Pressure Switches found above Technical Specification Allowable Values. The cause of the event was determined to be a procedure instruction deficiency, which promoted instrument set point drift.
Corrective actions included the revision of related maintenance procedures.
LER 2001-003, Unit 2 - Failure of Recirculation Pump Discharge Valve to close causing LPCI Inoperability. The cause of the event was determined to be inadequate procedural guidance, which led to the equipment failure. The corrective actions included the revision of appropriate station procedures.
G.
Component Failure Data
N/A
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05000249/LER-2003-001, Regarding Drywell Radiation Monitor Detector Not Fully Inserted | Regarding Drywell Radiation Monitor Detector Not Fully Inserted | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000237/LER-2003-001, Re Electromatic Relief Valve (ERV) Pressure Switches Drift Greater than Estimated | Re Electromatic Relief Valve (ERV) Pressure Switches Drift Greater than Estimated | 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000237/LER-2003-002, High Pressure Coolant Injection Room Cooler Bearing Degradation | High Pressure Coolant Injection Room Cooler Bearing Degradation | 10 CFR 50.73(a)(2)(v), Loss of Safety Function | 05000237/LER-2003-003, Reactor Feedwater Pump Trip and Automatic Reactor Scram | Reactor Feedwater Pump Trip and Automatic Reactor Scram | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000237/LER-2003-004, Regarding HPCI System Inoperable Due to Leaking Gland Seal Leak Off Pump Check and Regulating Valves | Regarding HPCI System Inoperable Due to Leaking Gland Seal Leak Off Pump Check and Regulating Valves | 10 CFR 50.73(a)(2)(v), Loss of Safety Function | 05000237/LER-2003-005, Regarding Main Steam Isolation Valve Leakage Exceeding Technical Specification Limit | Regarding Main Steam Isolation Valve Leakage Exceeding Technical Specification Limit | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000237/LER-2003-006, Regarding Torus Purge Valve Open in Conjunction with the Drywell Purge Valve in Mode 2 | Regarding Torus Purge Valve Open in Conjunction with the Drywell Purge Valve in Mode 2 | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000237/LER-2003-007, Regarding Manual Scram Due to High Stator Water Cooling System Temperature | Regarding Manual Scram Due to High Stator Water Cooling System Temperature | 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
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