05-18-2016 | On March 19, 2016, two block-out penetrations separating the Arkansas Nuclear One, Unit 1 (ANO-1) Turbine Building from the Auxiliary Building were determined to be non-functional. The penetrations are located in the floor of Turbine Building elevation 354 ft. Below the penetrations is the Auxiliary Building, housing safety related equipment.
On March 17, 2016, it was identified that two penetration seals did not match approved fire penetration or approved flood seal details. Further investigation, completed on March 19, 2016, revealed that the two block-out penetrations were not grouted and represented a previously unknown vulnerability in a credited external flood barrier.
The apparent cause of this event was less than adequate project management control for the size and scope of the External Flood Mitigation Project associated with post Fukushima Dai-ichi resolutions and requirements set forth by the NRC.
Mitigating strategies and extent of condition reviews have been implemented for the identified conditions. Permanent repair of the deficient flood barriers is complete minus cure time. Actions to correct programmatic aspects of this condition are in progress. |
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Category:Letter
MONTHYEARIR 05000368/20253012024-09-0909 September 2024 Notification of NRC Initial Operator Licensing Examination 05000368/2025301 ML24255A8642024-09-0606 September 2024 Rscc Wire & Cable LLC Dba Marmon Industrial Energy & Infrastructure - Part 21 Retraction of Final Notification IR 05000313/20240112024-09-0505 September 2024 Comprehensive Engineering Team Inspection Report 05000313/2024011 and 05000368/2024011 IR 05000313/20244042024-08-29029 August 2024 Cybersecurity Inspection Report 05000313/2024404 and 05000368/2024404 ML24239A3972024-08-23023 August 2024 Rssc Wire & Cable LLC Dba Marmon - Part 21 Final Notification - 57243-EN 57243 IR 05000313/20240052024-08-21021 August 2024 Updated Inspection Plan for Arkansas Nuclear One – Units 1 and 2 (Report 05000313/2024005, 05000368/2024005) ML24198A0722024-08-21021 August 2024 Correction to Issuance of Amendment No. 333 Revision to Technical Specifications to Adopt TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b ML24220A2642024-08-20020 August 2024 Entergy Operations, Inc. - Entergy Fleet Project Manager Assignment ML24185A1522024-08-13013 August 2024 Issuance of Amendment Nos. 334, 235, and 215, Respectively, to Revise TSs to Adopt TSTF-205 IR 05000313/20240022024-08-0606 August 2024 Integrated Inspection Report 05000313/2024002 and 05000368/2024002 ML24208A0962024-07-25025 July 2024 57243-EN 57243 - Rssc Wire & Cable LLC, Dba Marmon - Part 21 Notification ML24101A1792024-06-25025 June 2024 Issuance of Amendment No. 333 Revision to Technical Specifications to Adopt TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b ML24143A0632024-05-22022 May 2024 Notification of Inspection (NRC Inspection Report 05000368/2024003) and Request for Information IR 05000313/20240012024-05-0808 May 2024 Integrated Inspection Report 05000313/2024001 and 05000368/2024001 ML24128A2472024-05-0808 May 2024 Project Manager Assignment ML24017A2982024-04-18018 April 2024 Summary of Regulatory Audit Regarding the License Amendment Request to Revise Technical Specifications to Adopt TSTF 505, Revision 2, Provide Risk-Informed Extended Completion Times RITSTF Initiative 4b ML24107A0282024-04-17017 April 2024 Notification of Comprehensive Engineering Team Inspection (05000313/2024011 and 05000368/2024011) and Request for Information IR 05000313/20243012024-04-16016 April 2024 NRC Examination Report 05000313/2024301 ML24086A5412024-04-10010 April 2024 Authorization of Request for Alternative ANO1-ISI-037 Regarding Extension of Reactor Vessel Inservice Inspection Interval IR 05000313/20244022024-04-0808 April 2024 Security Baseline Inspection Report 05000313/2024402 and 05000368/2024402 (Full Report) ML24089A2262024-03-29029 March 2024 Entergy Response to Regulatory Issue Summary 2024-01, Preparation and Scheduling of Operator Licensing Exams ML24075A1712024-03-15015 March 2024 Nuclear Onsite Property Damage Insurance (10 CFR 50.54(w)(3)) ML24074A2892024-03-14014 March 2024 Proof of Financial Protection (10 CFR 140.15) ML24031A6442024-03-14014 March 2024 Issuance of Amendment No. 282 to Modify Technical Specification 3.3.1, Reactor Pressure System (RPS) Instrumentation, Turbine Trip Function on Low Control Oil Pressure ML24102A1342024-03-12012 March 2024 AN1-2024-03 Post Exam Submittal IR 05000313/20230062024-02-28028 February 2024 Annual Assessment Letter for Arkansas Nuclear One- Units 1 and 2 Report 05000313/2023006 and 05000368/2023006 IR 05000313/20230042024-02-0808 February 2024 Integrated Inspection Report 05000313/2023004 and 05000368/2023004 and Independent Spent Fuel Storage Installation Inspection Report 07200013/2023002 ML24012A0502024-02-0202 February 2024 Exemption from Select Requirements of 10 CFR Part 73 (EPID L-2023-LLE-0054 (Security Notifications, Reports, and Recordkeeping and Suspicious Activity Reporting)) ML23326A0392024-01-24024 January 2024 Issuance of Amendment No. 281 Revision to Technical Specifications to Adopt TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b ML24017A1582024-01-17017 January 2024 Submittal of Emergency Plan Revision 50 IR 05000313/20234202024-01-10010 January 2024 Security Baseline Inspection Report 05000313/2023420 and 05000368/2023420 IR 05000313/20234022024-01-0202 January 2024 Security Baseline Inspection Report 05000313/2023402 and 05000368/2023402 ML23349A1672023-12-21021 December 2023 Request for Withholding Information from Public Disclosure ML23354A0022023-12-21021 December 2023 Request for Withholding Information from Public Disclosure ML23348A3572023-12-14014 December 2023 Application to Revise Technical Specifications to Use Online Monitoring Methodology – Slides and Affidavit for Pre-Submittal Meeting ML23352A0292023-12-13013 December 2023 Entergy - 2024 Nuclear Energy Liability Evidence of Financial Protection ML23340A1592023-12-13013 December 2023 Entergy Operations, Inc. - Entergy Fleet Project Manager Assignment IR 05000313/20234052023-12-12012 December 2023 – Security Baseline Inspection Report 05000313/2023405 and 05000368/2023405 ML23341A0832023-12-11011 December 2023 – Material Control and Accounting Program Inspection Report 05000313/368/2023404- Cover Letter ML23305A0922023-12-0707 December 2023 Summary of Regulatory Audit Regarding License Amendment Request to Revise Technical Specifications to Adopt TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times RITSTF Initiative 4b ML23333A1362023-11-29029 November 2023 Supplement to Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation ML23275A2072023-11-28028 November 2023 Issuance of Amendment No. 280 Removal of Technical Specification Condition Allowing Two Reactor Coolant Pump Operation IR 05000313/20230032023-11-21021 November 2023 Revised - ANO Revised Integrated Inspection Report 05000313/2023003 and 05000368/2023003 and Independent Spent Fuel Storage Installation Inspection Report 07200013/ 2023001 ML23325A1412023-11-21021 November 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation ML23243B0452023-11-13013 November 2023 Request for Withholding Information from Public Disclosure ML23313A0962023-11-13013 November 2023 Integrated Inspection Report 05000313/2023003 and 05000368/2023003 and Independent Spent Fuel Storage Installation Inspection Report 07200013/2023001 ML23311A2082023-11-0909 November 2023 Reassignment of U.S. Nuclear Regulatory Commission Branch Chief in the Division of Operating Reactor Licensing for Plant Licensing Branch IV IR 05000313/20230112023-10-10010 October 2023 Commercial Grade Dedication Inspection Report 05000313/2023011 and 05000368/2023011 IR 05000313/20230052023-08-21021 August 2023 Updated Inspection Plan for Arkansas Nuclear One, Units 1 and 2 (Report 05000313/2023005 and 05000368/2023005) - Mid Cycle IR 05000313/20230022023-08-11011 August 2023 Integrated Inspection Report 05000313/2023002 and 05000368/2023002 and Notice of Violation 2024-09-09
[Table view] Category:Licensee Event Report (LER)
MONTHYEAR1CAN072402, Source Range Nuclear Instrument Failure Resulting in Condition Prohibited by Technical Specifications2024-07-0101 July 2024 Source Range Nuclear Instrument Failure Resulting in Condition Prohibited by Technical Specifications ML20135G7222020-05-14014 May 2020 Final ASP Analysis - ANO 1 (LER 313-96-005) 05000313/LER-2017-0022017-07-26026 July 2017 High Pressure Injection Pump Inoperable for Greater Than Technical Specification Completion Time, LER 17-002-00 for Arkansas Nuclear One, Unit 1, Regarding High Pressure Injection Pump Inoperable for Greater Than Technical Specification Completion Time 05000368/LER-2017-0022017-06-26026 June 2017 Automatic Start of an Emergency Diesel Generator Due to the Momentary Loss of Offsite Power due to Severe Weather, LER 17-002-00 for Arkansas Nuclear One, Unit 2, Regarding Automatic Start of an Emergency Diesel Generator Due to the Momentary Loss of Offsite Power due to Severe Weather 05000313/LER-2017-0012017-06-26026 June 2017 Automatic Start of an Emergency Diesel Generator Due to the Loss of Offsite Power due to Severe Weather, LER 17-001-00 for Arkansas Nuclear One, Unit 1, Regarding Automatic Start of an Emergency Diesel Generator Due to the Loss of Offsite Power due to Severe Weather 05000313/LER-2016-0032017-06-0909 June 2017 Tornado Missile Vulnerabilities Resulting in Unanalyzed Condition, LER 16-003-01 for Arkansas Nuclear One, Unit 1 Regarding Tornado Missile Vulnerabilities Resulting in Unanalyzed Condition 05000368/LER-2017-0012017-05-30030 May 2017 Inadequate Protection from Tornado Missiles Identified Due to Nonconforming Design Conditions, LER 17-001-00 for Arkansas Nuclear One, Unit 2, Regarding Inadequate Protection from Tornado Missiles Identified Due to Nonconforming Design Conditions 05000313/LER-2016-0042016-11-29029 November 2016 Decay Heat Removal System Socket Weld Leak due to a Vibration-Induced Fatigue Crack, LER 16-004-00 for Arkansas Nuclear One, Unit 1, Regarding Decay Heat Removal System Socket Weld Leak Due to a Vibration-Induced Fatigue Crack 05000368/LER-2016-0012016-11-15015 November 2016 Failure of One Emergency Diesel Generator and Subsequent Required Shutdown of Arkansas Nuclear One, Unit 2, LER 16-001-00 for Arkansas Nuclear One, Unit 2, Regarding Failure of One Emergency Diesel Generator and Subsequent Required Shutdown 05000313/LER-2016-0022016-08-11011 August 2016 Tornado Missile Vulnerability Resulting in Condition Prohibited By Technical Specifications, LER 16-002-00 for Arkansas Nuclear One, Unit 1, Regarding Tornado Missile Vulnerability Resulting in Condition Prohibited By Technical Specifications 05000313/LER-2016-0012016-05-18018 May 2016 Non-Functional External Penetration Flood Seals, LER 16-001-00 for Arkansas Nuclear One, Unit 1, Regarding Non-Functional External Penetration Flood Seals 05000313/LER-2015-0012016-02-12012 February 2016 Manual Reactor Trio Due to Oscillations in the Feedwater System, LER 15-001-00 for Arkansas Nuclear One, Unit 1, Regarding Manual Reactor Trip Due to Oscillations in the Feedwater System 2CAN051405, LER 14-01-00 for Arkansas Nuclear One, Unit 2 Regarding Operation of Switchgear Rooms Ventilation Prohibited by Technical Specifications2014-05-15015 May 2014 LER 14-01-00 for Arkansas Nuclear One, Unit 2 Regarding Operation of Switchgear Rooms Ventilation Prohibited by Technical Specifications 0CAN050202, LER 02-S01-00 for Arkansas Nuclear One Units 1 and 2, Compensatory Measures Were Removed While a Security Perimeter Intrusion Detection Microwave Field Remained Disarmed2002-05-10010 May 2002 LER 02-S01-00 for Arkansas Nuclear One Units 1 and 2, Compensatory Measures Were Removed While a Security Perimeter Intrusion Detection Microwave Field Remained Disarmed 2024-07-01
[Table view] |
0001, or by intemet 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.
A. Background
The design basis flood protection elevation for Arkansas Nuclear One, Units 1 and 2 (ANO-1 and ANO- 2) safety- related components and structures is 361 ft. Mean Sea Level (MSL). The design basis flood is a combination of the probable maximum flood (PMF) (358 ft. MSL), which is based on a 10,000 year probability, and the assumed coincident failure of the upstream Ozark Dam (+3 ft.). The ANO-1 and ANO-2 Safety Analysis Reports (SARs) state that Seismic Class/Category 1 structures are designed for the PMF of 361 ft. MSL and Seismic Class/Category 1 systems and equipment are either located on floors above 361 ft. MSL or protected by walls, waterproof doors, hatches, etc.
B. Plant Status At the time the condition was discovered, ANO-1 and ANO-2 were operating in Mode 1 at 100% power. There were no other structures, systems, or components that were inoperable at the time that contributed to the event.
C. Event Description
ANO conducted walk downs and design verifications as follow-up activities in response to Near-Term Task Force (NTTF) Recommendation 2.3, "Flooding Walk down of the NTTF Review of Insights from the Fukushima Dai-ichi Accident." As previously reported in LER 50-313/2014-01-00 dated May 5, 2014, multiple instances of ANO-1 and ANO-2 design features that may not have provided adequate external flood protection for safety-related equipment located below the design basis flood elevation of 361 ft. MSL were documented during these walk downs. Examples of the identified deficient design features and procedures included:
- Missing or deficient internal conduit seals
- Missing or deficient seals
- Unsealed removable closure plates
- Ground water intrusion through penetrations, building joints and conduits
- Floor drain system cross connected between flood protected areas and non-flood areas Due to the lack of designed isolation features on these pathways, the potential existed for flood waters to migrate into the Auxiliary Building where pumps and equipment required for safe shutdown are located.
In March 2016, as part of follow-up actions, a list of dual-function penetrations (fire and flood) was being created to determine where there was a detail difference between the Fire Penetration Log and the Flood Features database.
Penetrations 00073-01-0034 and 0073-01-0063 were identified on the Fire Penetration Log as sealed with lathe and plaster; however, the Flood Features database indicated the penetrations were sealed with grout and/or cellular concrete. Lathe and plaster is sufficient for fire protection purposes, but unqualified for flood protection. This was documented in Condition Report CR-ANO-1-2016-0985 on March 17, 2016. No recent documentation could be located supporting the assertion that the penetrations were sealed with grout and/or cellular concrete. Follow-up field inspection confirmed the penetrations were sealed with lathe and plaster and the penetrations were declared non- functional for flood protection on March 19, 2016.
(See Page 2 for required number of digits/characters for each block) 0001, or by intemet 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.
D. Event Causes The direct cause of the event (failure to identify the lathe and plaster detail in two flood barrier block-out penetrations) is both the vendor preparer and reviewer failed to perform adequate verification of penetration details in drawings and the associated Flood Features database.
The apparent cause of this event is less than adequate project management control for the size and scope of the External Flood Mitigation Project.
The following contributing causes were also identified:
- Oversight personnel did not recognize and correct inadequate monitoring and management of the project as the scope and complexity increased.
- Flood design documents did not distinguish between lathe and plaster from grout, other than in the Fire Penetration Log, which was not accessible in the field.
- The preparer and reviewer did not follow design verification requirements. Penetration photographs were accepted as sufficient information for assigning incorrect details on architectural drawings and in the Flood Features database for the two block-out penetrations.
E. Corrective Actions
The following corrective actions have been completed to address this condition:
- Carbon steel forms were anchored to the floor around the subject block-out penetrations and sealing materials staged as a contingency until permanent repairs can be completed.
- A comprehensive review of the Flood Features database, Fire Protection Penetration Log, and architectural drawings has been performed. No further external flooding vulnerabilities were identified during this review.
- A human performance error review has been completed to document inappropriate action analysis.
The following corrective actions are being taken to further address this condition (list is not all inclusive):
- Entergy personnel and contractors responsible for gaps in oversight and accountability related to the external flooding project will be briefed on the importance of recognition and mitigation of the impacts of schedule pressures and changes in personnel assigned to the project.
- A detailed review of the vendor's root cause evaluation being developed will be performed and important results and actions from the review will be documented in the ANO corrective action plan.
- A review of completed external flood barrier walk-down packages is planned to determine if post verification entries in the walk-down package have been made without verification and to document the adequacy of all external flood boundary features (including vendor test data, qualification reports and other supporting documentation).
(See Page 2 for required number of digits/characters for each block) 0001, or by intemet 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.
F. Safety Significance Evaluation Arkansas Nuclear One is required to be protected from flooding within the station's design and licensing basis. The safety-related equipment required to mitigate the consequences of an accident were potentially affected by this condition. There are several factors which could mitigate the impact of these deficiencies depending on the specific conditions encountered during an actual event including the actual flood height, the capability for the subject block-out penetrations to resist water ingress, the sealing of pathways, and water removal actions. Should mitigating strategies fail, the unanalyzed pathways could permit an indeterminate amount of leakage into the Auxiliary building, potentially challenging the ability of safety-related equipment to perform the specified safety function during an accident. There were no actual consequences.
G. Basis for Reportability This event is reported pursuant to the following criteria:
10 CFR 50.73(a)(2)(ii):
Any event of condition that resulted in (B) The nuclear power plant being in an unanalyzed condition that significantly degraded plant safety 10 CFR 50.73(a)(2)(v) Any event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to:
(B) Remove residual heat (ANO-1 and ANO-2 Decay Heat Removal system)
H. Additional Information
10 CFR 50.73(b)(5) states that this report shall contain reference to "any previous similar events at the same plant that are known to the licensee." NU REG-1022 reporting guidance states that term "previous occurrences" should include previous events or conditions that involved the same underlying concern or reason as this event, such as the same root cause, failure, or sequence of events.
A review of the ANO corrective action program and Licensee Event Reports for the previous three years was performed. This review identified conditions that were previously identified deficiencies in the flood barrier program.
Two relevant similar events were identified. These events are discussed below.
On April 7, 2015, during preparation of walk down packages for flood barrier inspections, two credible flood paths were identified between an unscheduled junction box located in the ANO-2 Turbine Building (floor elevation 329 ft., approximately 4 feet off the floor) and lighting receptacles in the Auxiliary Building elevation 317 ft. The apparent cause of this condition was the failure to recognize a drawing note which identified the junction box seal in addition to the lighting panel seals.
In addition to the above, one Licensee Event Report (50-313/2014-001-00) was submitted to the NRC (described in Section C above) on May 5, 2014 (ML14125A483).
(See Page 2 for required number of digits/characters for each block) 0001, or by intemet 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.
Arkansas Nuclear One, Unit 1 05000-313 H. Additional Information (continued) The subject condition associated with this report (failure to identify the lathe and plaster detail in two flood barrier block-out penetrations) was identified as part of the ongoing External Flood Mitigation Project extent of condition review and is not associated with corrective actions intended to prevent recurrence. Additional corrective actions are initiated when further deficiencies are identified, as noted in the partial list provided in Section E above.
Energy Industry Identification System (El IS) codes and component codes are identified in the text of this report as [0q.
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05000368/LER-2016-001 | Failure of One Emergency Diesel Generator and Subsequent Required Shutdown of Arkansas Nuclear One, Unit 2 LER 16-001-00 for Arkansas Nuclear One, Unit 2, Regarding Failure of One Emergency Diesel Generator and Subsequent Required Shutdown | 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)(i)(A), Completion of TS Shutdown | 05000313/LER-2016-001 | Non-Functional External Penetration Flood Seals LER 16-001-00 for Arkansas Nuclear One, Unit 1, Regarding Non-Functional External Penetration Flood Seals | 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(ii) | 05000313/LER-2016-002 | Tornado Missile Vulnerability Resulting in Condition Prohibited By Technical Specifications LER 16-002-00 for Arkansas Nuclear One, Unit 1, Regarding Tornado Missile Vulnerability Resulting in Condition Prohibited By Technical Specifications | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000313/LER-2016-003 | Tornado Missile Vulnerabilities Resulting in Unanalyzed Condition LER 16-003-01 for Arkansas Nuclear One, Unit 1 Regarding Tornado Missile Vulnerabilities Resulting in Unanalyzed Condition | 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)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | 05000313/LER-2016-004 | Decay Heat Removal System Socket Weld Leak due to a Vibration-Induced Fatigue Crack LER 16-004-00 for Arkansas Nuclear One, Unit 1, Regarding Decay Heat Removal System Socket Weld Leak Due to a Vibration-Induced Fatigue Crack | 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident |
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