On March 30, 2017 at approximately 0922 EST, with Unit 1 at 97 percent rated thermal power and Unit 2 at 100 percent rated thermal power, it was identified that based on the revised Enforcement Guidance Memorandum (EGM) 15-002, Revision 1, the Emergency Diesel Generator ( EDG) fuel oil storage ventilation pipe extending approximately 5 feet above grade was reportable due to its nonconformance with tornado generated missile protection requirements. This condition caused the EDGs and their associated fuel oil storage system to be considered inoperable. However, due to implementing compensatory measures as required by EGM 15-002, the affected equipment was declared operable but non-conforming.
These tornado missile vulnerabilities have existed since original plant construction and is a design legacy issue.
Upon identification of the noncompliance, compensatory measures were taken to revise the abnormal procedure for natural occurring phenomena to include actions that must be taken for the diesel generator fuel oil storage tank vent lines following a tornado or high winds event. A design change is also being processed to prevent the vent lines from being impacted due to a tornado missile. |
Similar Documents at Hatch |
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Category:Letter
MONTHYEARIR 05000321/20240022024-08-0808 August 2024 Edwin I Hatch Nuclear Plants, Units 1 and 2 – Integrated Inspection Report 05000321-2024002 and 05000366-2024002 NL-24-0276, Post-Audit Supplement to License Amendment Request to Revise Renewed Facility Operating Licenses to Adopt an Alternative Seismic Method for Categorization of Structures, Systems, and Components2024-07-26026 July 2024 Post-Audit Supplement to License Amendment Request to Revise Renewed Facility Operating Licenses to Adopt an Alternative Seismic Method for Categorization of Structures, Systems, and Components NL-24-0290, Response to Request for Additional Information Related to Request for Specific Exemption2024-07-26026 July 2024 Response to Request for Additional Information Related to Request for Specific Exemption NL-24-0261, 10 CFR 50.46 ECCS Evaluation Model Annual Report for 20232024-07-19019 July 2024 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2023 ML24198A1252024-07-16016 July 2024 Edwin I Hatch Nuclear Plant Units 1 - 2 Notification of Conduct of Title 10 of the Code of Federal Regulations 50 NL-24-0260, Inservice Inspection Program Owner’S Activity Report (OAR-1) for Refueling Outage 1R312024-07-0909 July 2024 Inservice Inspection Program Owner’S Activity Report (OAR-1) for Refueling Outage 1R31 NL-24-0143, Proposed Alternative to Use ASME Code Case N-752, Risk-Informed Categorization and Treatment for Repair/ Replacement Activities in2024-06-27027 June 2024 Proposed Alternative to Use ASME Code Case N-752, Risk-Informed Categorization and Treatment for Repair/ Replacement Activities in NL-24-0239, Response to Apparent Violation in NRC Inspection Report 05000321, 366/2024090: EA-23-1392024-06-17017 June 2024 Response to Apparent Violation in NRC Inspection Report 05000321, 366/2024090: EA-23-139 ML24163A0532024-06-14014 June 2024 Audit Plan - Alternative Seismic Method LAR ML24149A0492024-06-0404 June 2024 SNC Fleet - Regulatory Audit in Support of Review of the License Amendment Request to Revise TS 1.1, Use and Application Definitions, and Add New Technical Specification 5.5.21 and 5.5.17, Online Monitoring Program, NL-24-0148, Report of Changes to Emergency Plan and Summary of 50.54(q) Analysis2024-06-0404 June 2024 Report of Changes to Emergency Plan and Summary of 50.54(q) Analysis NL-24-0202, SNC Response to Regulatory Issue Summary 2024-01: Preparation and Scheduling of Operator Licensing Examinations2024-05-24024 May 2024 SNC Response to Regulatory Issue Summary 2024-01: Preparation and Scheduling of Operator Licensing Examinations NL-24-0191, Annual Radiological Environmental Operating Reports for 20232024-05-10010 May 2024 Annual Radiological Environmental Operating Reports for 2023 NL-24-0195, Response to Request for Additional Information Regarding License Amendment Request to Revise Technical Specifications to Adopt Risk Informed Completion Times for Residual Heat Removal Service Water.2024-05-0707 May 2024 Response to Request for Additional Information Regarding License Amendment Request to Revise Technical Specifications to Adopt Risk Informed Completion Times for Residual Heat Removal Service Water. NL-24-0064, Units 1 & 2 and Hatch Nuclear Plant - Units 1 & 2 License Amendment Request to Revise Technical Specification 1.1 and Add Online Monitoring Program to Technical Specification 5.52024-05-0303 May 2024 Units 1 & 2 and Hatch Nuclear Plant - Units 1 & 2 License Amendment Request to Revise Technical Specification 1.1 and Add Online Monitoring Program to Technical Specification 5.5 IR 05000032/20240112024-04-25025 April 2024 Notification of Edwin I. 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Hatch Nuclear Plant, Units 1 & 2 - Report 05000321/2023005 and 05000366/2023005 NL-23-0658, Southern Nuclear Operating Company - Response to Request for Additional Information Regarding Quality Assurance Topical Report Submittal2023-08-11011 August 2023 Southern Nuclear Operating Company - Response to Request for Additional Information Regarding Quality Assurance Topical Report Submittal NL-23-0542, CFR 50.46 ECCS Evaluation Model Annual Report for 20222023-08-0909 August 2023 CFR 50.46 ECCS Evaluation Model Annual Report for 2022 IR 05000321/20230022023-08-0808 August 2023 Integrated Inspection Report 07200036/2023001, 05000321/2023002, and 05000366/2023002 NL-23-0624, Report of Changes to Emergency Plan and Summary of 50.54(q) Analysis2023-08-0404 August 2023 Report of Changes to Emergency Plan and Summary of 50.54(q) Analysis ML23202A1122023-08-0202 August 2023 Units, 1 and 2; and Vogtle Units 1 and 2 - Request to Use a Provision of a Later Edition of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section XI ML23201A0292023-07-20020 July 2023 Notification of Inspection and Request for Information for NRC Problem Identification and Resolution Inspection NL-23-0566, ISFSI and Edwin I. Hatch Nuclear Plant ISFSI - Registration of Spent Fuel Cask Use2023-07-13013 July 2023 ISFSI and Edwin I. Hatch Nuclear Plant ISFSI - Registration of Spent Fuel Cask Use NL-23-0555, Request for Exemption from Physical Barrier Requirement2023-07-0707 July 2023 Request for Exemption from Physical Barrier Requirement ML23178A0012023-06-27027 June 2023 Information Request for the Cyber-Security Baseline Inspection, Notification to Perform Inspection 05000321 2023403 and 05000366 2023403 NL-23-0444, Quality Assurance Topical Report Submittal2023-06-15015 June 2023 Quality Assurance Topical Report Submittal NL-23-0457, ISFSI, and Edwin I. Hatch Nuclear Plant, ISFSI - Registration of Spent Fuel Cask Use2023-06-12012 June 2023 ISFSI, and Edwin I. Hatch Nuclear Plant, ISFSI - Registration of Spent Fuel Cask Use IR 05000321/20230102023-06-0909 June 2023 Focused Engineering Inspection Report 05000321 2023010 and 05000366 2023010 NL-23-0422, Inservice Inspection Program Owner'S Activity Report for Refueling Outage 2R272023-05-30030 May 2023 Inservice Inspection Program Owner'S Activity Report for Refueling Outage 2R27 2024-08-08
[Table view] Category:Licensee Event Report (LER)
MONTHYEARNL-20-0230, Edwin I. Hatch Nuclear Plant, Unit 2, Primary Containment Penetration Exceeded Maximum Allowable Primary Containment Leakage Rate (La)2020-03-0202 March 2020 Edwin I. Hatch Nuclear Plant, Unit 2, Primary Containment Penetration Exceeded Maximum Allowable Primary Containment Leakage Rate (La) 05000366/LER-2020-0012020-03-0202 March 2020 LER 2020-001-00 for Edwin I. Hatch Nuclear Plant, Unit 2, Primary Containment Penetration Exceeded Maximum Allowable Primary Containment Leakage Rate (La) 05000321/LER-2017-0042017-08-24024 August 2017 Tornado Missile Vulnerabilities Result in Condition Prohibited by Technical Specifications, LER 17-004-00 for Edwin I. Hatch Regarding Safety Relief Valves' as Found Settings Resulted in Not Meeting Tech Spec Surveillance Criteria 05000366/LER-2017-0022017-04-13013 April 2017 Emergency Diesel Generator Start Due to Inadvertent Electrical Bus De-Energization, LER 17-002-00 for Edwin I. Hatch, Unit 2, Regarding Emergency Diesel Generator Start Due to Inadvertent Electrical Bus De-Energization 05000366/LER-2017-0032017-04-13013 April 2017 LER 17-003-00 for Edwin I. Hatch, Unit 2, Regarding Primary Containment Isolation Penetration Exceeded Overall Allowable Technical Specification Leakage Limits 05000321/LER-2017-0022017-04-0707 April 2017 High Pressure Coolant Injection System Declared Inoperable Due to Degraded Inverter, LER 17-002-00 for Edwin I. Hatch, Unit 1, Regarding High Pressure Coolant Injection System Declared Inoperable Due to Degraded Inverter 05000366/LER-2016-0042017-01-0303 January 2017 Condition Prohibited by Technical Specifications Due to Inoperable PCIV, LER 16-004-00 for Edwin I. Hatch Nuclear Plant, Unit 2, Regarding Condition Prohibited by Technical Specifications Due to Inoperable PCIV 05000366/LER-2016-0022016-07-13013 July 2016 Group I Isolation Received During Turbine Testing, LER 16-002-00 for Edwin I. Hatch, Unit 2, Regarding Group 1 Isolation Received During Turbine Testing 05000366/LER-2016-0012016-06-0808 June 2016 2C EDG Fuel Oil Relief Valve Leakage Caused Train Inoperability, LER 16-001-00 for E.I. Hatch, Unit 2, Regarding 2C EDG Fuel Oil Relief Valve Leakage Caused Train Inoperability 05000321/LER-2016-0042016-05-26026 May 2016 Safety Relief Valves As Found Settings Resulted in Not Meeting Tech Spec Surveillance Criteria, LER 16-004-00 for Edwin I. Hatch Nuclear Plant Unit 1 RE: Safety Relief Valves as Found Settings Resulted in Not Meeting Tech Spec Surveillance Criteria 05000321/LER-2016-0032016-04-14014 April 2016 Reactor Coolant System Piping Has Unacceptable Weld Indication Discovered During Refueling Outage, LER 16-003-00 for E.I. Hatch, Unit 1, Regarding Reactor Coolant System Piping Has Unacceptable Weld Indication Discovered During Refueling Outage 05000321/LER-2016-0022016-04-11011 April 2016 Performance of Operations With the Potential to Drain the Reactor Vessel (OPDRV) Without Secondary Containment, LER 16-002-00 for E.I Hatch, Unit 1, Regarding Performance of Operations With the Potential to Drain the Reactor Vessel (OPDRV) Without Secondary Containment 05000321/LER-2016-0012016-04-0808 April 2016 Performance of Fuel Movement with Inoperable Rod Position Indication System in Violation of Technical Specifications, LER 16-001-00 for Edwin I. Hatch, Unit 1, Regarding Performance of Fuel Movement With Inoperable Rod Position Indication System in Violation of Technical Specifications NL-08-1906, LER 08-S01-00, for Edwin I. Hatch, Failure to Report Arrest Results in Inappropriate Access to Protected and Vital Areas2008-12-19019 December 2008 LER 08-S01-00, for Edwin I. Hatch, Failure to Report Arrest Results in Inappropriate Access to Protected and Vital Areas ML1019404552008-05-0808 May 2008 Southern Nuclear Plant E. I. Hatch - Actions for Potential Groundwater Contamination Events NL-06-2726, LER 06-S01-00 for Edwin I. Hatch Nuclear Plant, Re Contract Employee Failure to Self-Disclose Material Information for Unescorted Access2006-12-0505 December 2006 LER 06-S01-00 for Edwin I. Hatch Nuclear Plant, Re Contract Employee Failure to Self-Disclose Material Information for Unescorted Access ML17252B4401976-04-15015 April 1976 LER 76-026-00 for Hatch, Unit 1 Regarding an Occurrence of Open Links in Panel H11-P601 Defeating the Starting of All RHR Pumps After They Had Been Stopped 2020-03-02
[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.
Edwin I. Hatch Nuclear Plant Unit 1 05000-321
NO
Event Description
Each of the five Hatch Nuclear Plant Emergency Diesel Generators (EDGs) have a buried diesel fuel oil storage tank that is vented to the atmosphere through a single pipe. On August 31, 2015, this ventilation piping was verified to extend 5 feet above grade for each EDG fuel oil storage tank. Therefore, in the event a tornado generated missile struck the unprotected piping, each fuel oil storage system would be susceptible to degradation based on either water intrusion or lack of available ventilation to the tank. This condition caused the EDGs and their associated fuel oil storage system to be considered inoperable. However, due to implementing compensatory measures as required by Enforcement Guidance Memorandum (EGM) 15-002, the affected equipment was declared operable but non-conforming.
On March 30, 2017 at approximately 0922 EST, with Unit 1 at 97 percent rated thermal power and Unit 2 at 100 percent rated thermal power, it was identified that based on the revised EGM 15-002, Revision 1, the EDG fuel oil storage ventilation pipe extending approximately 5 feet above grade was reportable due to its nonconformance with tornado generated missile protection requirements.
Event Cause Analysis This condition is a legacy design issue. Due to the historical nature of this vulnerability, a specific cause has not been identified.
Safety Assessment This event is reportable per 10 CFR 50.73(a)(2)(i)(B) as condition prohibited by Technical Specifications, per 10 CFR 50.73(a)(2)(ii)(B) as an event or condition that resulted in the plant being in an unanalyzed condition that significantly degraded plant safety, and per 10 CFR 50.73(a)(2)(v)(D) as an event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident.
The diesel generator fuel oil system consists of five independent trains of equipment with each train supplying fuel oil to its respective diesel generator. The standby ac power supply consists of five diesel generators and supplies standby power to the 4160-V emergency service buses. The fuel oil system is composed of storage tanks, day tanks, transfer pumps, and associated piping, valves, filters, and controls. Transfer capability between storage tanks of different trains is provided by a transfer header.
The fuel supply for the diesel engines consists of five 40,000-gallon main fuel storage tanks. These storage tanks have 8 feet of ground cover and are separated from adjacent tanks by 8 feet. The storage tanks can supply any diesel engine. Additionally, each diesel generator is equipped with a 1000-gallon capacity day tank.
Each main tank is equipped with two 100 percent capacity fuel oil transfer pumps which are supplied power from different division sources. Each of these redundant pumps may discharge into one of the five 1000-gallon day tanks. All outside tanks, piping, pumps, and valves are underground.
As documented in EGM 15-002, tornado missile scenarios that may lead to core damage are very low 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.
Edwin I. Hatch Nuclear Plant Unit 1 05000-321
NO
probability events because safety-related SSCs are typically designed to withstand effects of tornados. For a tornado missile-induced scenario to occur, a tornado would have to touch down at the site and result in the generation of missiles that would hit and fail vulnerable, unprotected safety-related equipment, and/or unprotected safety-related subcomponents in a manner that is non-repairable and non-recoverable. In addition, because plants are designed with redundancy and diversity, the tornado missiles would have to affect multiple trains of safety systems and/or means of achieving safe shutdown.
The NRC has completed a generic risk analysis of potential tornado missile protection non-compliances to examine the risk significance of these scenarios. This assessment documents a conservative, bounding-type analysis of the risk significance for plant facilities. The generic analysis assumed that core damage would occur if a tornado hit a plant located in the most active tornado region in the country and that it caused a tornado-generated missile to fail all emergency core cooling equipment at the plant with no ability to recover.
Given this conservative assumption, it has been determined that the core damage frequency (CDF) associated with tornado missile related non-compliances is well below CDF requiring immediate regulatory action.
Therefore, the generic bounding risk analysis performed by the NRC concluded that this issue is of low risk significance.
During a postulated design basis tornado, the unprotected diesel fuel oil storage tank ventilation piping could result in the degradation of the ventilation piping such that the fuel oil storage system is degraded. However, because Hatch has not experienced an actual tornado missile event, this event is considered to have very low safety significance.
Corrective Actions
Upon identification of the noncompliance, compensatory measures were taken to revise the abnormal procedure for natural occurring phenomena to include actions that must be taken for the diesel generator fuel oil storage tank vent lines following a tornado or high winds event. A design change is also being processed to prevent the vent lines from being impacted due to a tornado missile.
Previous Similar Events
None.
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05000366/LER-2017-001 | 1 OF 3 | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000366/LER-2017-002 | Emergency Diesel Generator Start Due to Inadvertent Electrical Bus De-Energization LER 17-002-00 for Edwin I. Hatch, Unit 2, Regarding Emergency Diesel Generator Start Due to Inadvertent Electrical Bus De-Energization | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000321/LER-2017-002 | High Pressure Coolant Injection System Declared Inoperable Due to Degraded Inverter LER 17-002-00 for Edwin I. Hatch, Unit 1, Regarding High Pressure Coolant Injection System Declared Inoperable Due to Degraded Inverter | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | 05000366/LER-2017-003 | LER 17-003-00 for Edwin I. Hatch, Unit 2, Regarding Primary Containment Isolation Penetration Exceeded Overall Allowable Technical Specification Leakage Limits | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded | 05000321/LER-2017-004 | Tornado Missile Vulnerabilities Result in Condition Prohibited by Technical Specifications LER 17-004-00 for Edwin I. Hatch Regarding Safety Relief Valves' as Found Settings Resulted in Not Meeting Tech Spec Surveillance Criteria | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
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