11-13-2017 | On September 27, 2017, at approximately 10:00 a.m. CDT, with the plant operating at 85 percent power, a door in the auxiliary building pressure boundary was left unsecured by an employee entering the building. The employee failed to fully close the door, and then did not properly challenge the door to confirm its security prior to leaving the area. A security officer responded to the resulting alarm, and fully closed the door approximately four minutes later. Since the worker had sufficient experience with watertight doors to know their proper operation, this event is considered a skill-based error caused by over-confidence and improper assumptions. Having successfully used such doors numerous times, the worker was confident in the ability to do so. The effort to check the door's security by pushing it failed, likely due to its heavy mass.
A briefing memorandum was issued from the general manager to site personnel. Tamper alarms were installed on all watertight doors in the secondary containment boundary to provide an audible indication that the door is open.
Administrative controls have been instituted to schedule routine battery replacements. |
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LER-2017-009, Potential Loss of Safety Function of Secondary Containment due to Unsecured Personnel DoorDocket Number |
Event date: |
09-27-2017 |
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Report date: |
11-13-2017 |
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Reporting criterion: |
10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material |
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4582017009R00 - NRC Website |
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Category:Letter
MONTHYEARIR 05000458/20230402024-01-18018 January 2024 95001 Supplemental Inspection Supplemental Report 05000458/2023040 and Follow-Up Assessment Letter ML24012A1962024-01-12012 January 2024 Response to 2nd Round Request for Additional Information Concerning Relief Request Number EN-RR-22-001 Proposed Alternative to Use ASME Code Case N-752, Risk-Informed Categorization and RBG-48271, Supplement to License Amendment Request to Adopt Risk Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times RITSTF Initiative 4b and Application to Adopt 10 CFR 50.69, Risk2024-01-12012 January 2024 Supplement to License Amendment Request to Adopt Risk Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times RITSTF Initiative 4b and Application to Adopt 10 CFR 50.69, Risk ML24011A1742024-01-11011 January 2024 Security Baseline Inspection Report (Cover Letter) ML23349A1672023-12-21021 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 ML23340A1592023-12-13013 December 2023 Entergy Operations, Inc. - Entergy Fleet Project Manager Assignment ML23352A0292023-12-13013 December 2023 Entergy - 2024 Nuclear Energy Liability Evidence of Financial Protection IR 05000458/20230102023-12-12012 December 2023 Biennial Problem Identification and Resolution Inspection Report 05000458/2023010 RBG-48267, Reply to a Notice of Violation, NRC Inspection Report 05000458/20230032023-12-0707 December 2023 Reply to a Notice of Violation, NRC Inspection Report 05000458/2023003 ML23333A1362023-11-29029 November 2023 Supplement to Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation ML23325A1432023-11-21021 November 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation IR 05000458/20230032023-11-13013 November 2023 Integrated Inspection Report 05000458/2023003 ML23310A0322023-11-13013 November 2023 Integrated Inspection Report 05000458/2023003 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 ML23311A4322023-11-0909 November 2023 Notification of NRC Supplemental Inspection (95001) and Request for Information RBG-48264, Core Operating Limits Report (COLR) - Cycle 23, Revision 12023-11-0606 November 2023 Core Operating Limits Report (COLR) - Cycle 23, Revision 1 RBG-48260, Notification of Readiness for Supplemental Inspection2023-10-12012 October 2023 Notification of Readiness for Supplemental Inspection ML23278A2402023-10-0606 October 2023 Regulatory Audit Plan in Support of License Amendment Requests to Revise TSs to Adopt Risk-Informed Completion Times and Implement the Provisions of 10 CFR 50.69 RBG-48258, Notification of Readiness for Supplemental Inspection2023-10-0505 October 2023 Notification of Readiness for Supplemental Inspection RBG-48259, Revision to Reply to Notice of Violation; EA-23-0552023-10-0303 October 2023 Revision to Reply to Notice of Violation; EA-23-055 ML23270B9932023-09-29029 September 2023 Request to Update ASME Boiler & Pressure Vessel Code Relief Request SE with NRC-Approved Revision of Bwrip Guidelines (GG-ISI-020 & RBS-ISI-019) (EPID L-2022-LLR-0090) - Non-Proprietary ML23269A1242023-09-27027 September 2023 Request for Withholding Information from Public Disclosure IR 05000458/20234012023-09-26026 September 2023 Cyber Security Inspection Report 05000458/2023401 IR 05000458/20230012023-09-21021 September 2023 NRC Inspection Report 05000458/2023001, Disputed Non-Cited Violation Rescinded RBG-48254, Report of Changes and Errors to 10CFR50.462023-09-21021 September 2023 Report of Changes and Errors to 10CFR50.46 IR 05000458/20234032023-09-21021 September 2023 NRC Security Inspection Report 05000458/2023403 (Cover Letter) RBG-48249, Reply to a Notice of Violation, EA-23-0712023-09-14014 September 2023 Reply to a Notice of Violation, EA-23-071 RBG-48253, Submittal of Owner'S Activity Report Form for Cycle 222023-09-12012 September 2023 Submittal of Owner'S Activity Report Form for Cycle 22 IR 05000458/20230122023-09-0101 September 2023 Comprehensive Engineering Team Inspection Report 05000458/2023012 IR 05000458/20230052023-08-21021 August 2023 Updated Inspection Plan for River Bend Station (Report 05000458/2023005) - Mid Cycle Letter RBG-48247, Reply to Notice of Violation; EA-23-0552023-08-21021 August 2023 Reply to Notice of Violation; EA-23-055 IR 05000458/20230922023-08-15015 August 2023 Final Significance Determination of a White Finding, Notice of Violation, and Follow-Up Assessment Letter; NRC Inspection Report 05000458/2023092 IR 05000458/20230022023-08-0909 August 2023 Integrated Inspection Report 05000458/2023002 ML23208A2112023-07-27027 July 2023 Entergy Operations Inc., Application to Revise Technical Specifications to Adopt TSTF-205, Revision of Channel Calibration, Channel Functional Test, and Related Definitions ML23195A0692023-07-24024 July 2023 2023 River Bend Station Notification of Biennial Problem Identification and Resolution Inspection and Request for Information IR 05000458/20230912023-07-20020 July 2023 Final Significance Determination of a White Finding, Notice of Violation, and Follow-Up Assessment Letter; NRC Inspection Report 05000458/2023091 ML23207A0762023-07-14014 July 2023 EN 56557 - Update to Part 21 Report Re Potential Defect with Trane External Auto/Stop Emergency Stop Relay Card Pn: XI2650728-06 ML23195A0222023-07-11011 July 2023 4-2022-012 Letter - OI Closure to Licensee IR 05000458/20234042023-07-11011 July 2023 NRC Security Inspection Report 05000458/2023404 (Cover Letter Only) IR 05000458/20230902023-06-26026 June 2023 NRC Inspection Report 05000458/2023090 and Preliminary White Finding ML23159A2302023-06-0808 June 2023 Response to Request for Additional Information Concerning Request to Update ASME Code Relief Request Safety Evaluations with NRC-Approved Revision of BWRVIP Guidelines (GG-ISI-020, and RBS-ISI-019) ML23159A0052023-06-0505 June 2023 56557-EN 56557 - Paragon - Redlined RBG-48226, Core Operating Limits Report (COLR) - Cycle 23, Revision 02023-05-31031 May 2023 Core Operating Limits Report (COLR) - Cycle 23, Revision 0 RBG-48237, Response to NRC Integrated Inspection Report 05000458/20230012023-05-25025 May 2023 Response to NRC Integrated Inspection Report 05000458/2023001 ML23130A2732023-05-10010 May 2023 and Waterford 3 Steam Electric Station - Response to Regulatory Issue Summary 2023-01, Preparation and Scheduling of Operator Licensing Examinations ML23116A2352023-05-0101 May 2023 Integrated Inspection Report 05000458/2023001 ML23117A2172023-05-0101 May 2023 Safety Evaluation for Quality Assurance Program Manual Reduction in Commitment RBG-48221, 2022 Annual Radiological Environmental Operating Report2023-04-25025 April 2023 2022 Annual Radiological Environmental Operating Report 2024-01-18
[Table view] Category:Licensee Event Report (LER)
MONTHYEAR05000458/LER-2017-0092017-11-13013 November 2017 Potential Loss of Safety Function of Secondary Containment due to Unsecured Personnel Door, LER 17-009-00 for River Bend, Unit 1 Regarding Potential Loss of Safety Function of Secondary Containment due to Unsecured Personnel Door 05000458/LER-2017-0072017-08-21021 August 2017 Automatic Reactor Scram due to Failure of Main Generator Voltage Regulator Mode Transfer Relay, LER 17-007-00 for River Bend Station - Unit 1 Regarding Automatic Reactor Scram due to Failure of Main Generator Voltage Regulator Mode Transfer Relay 05000483/LER-2017-0012017-08-15015 August 2017 Violation of Technical Specification 3.7.9 Due to Ultimate Heat Sink (UHS) Cooling Tower Train Inoperability, LER 17-001-00 for Callaway, Unit 1, Regarding Violation of Technical Specification 3.7.9 Due to Ultimate Heat Sink (UHS) Cooling Tower Train Inoperability 05000286/LER-2017-0022017-08-0909 August 2017 Manual Isolation of Chemical and Volume Control System Normal Letdown to Stop a Valve Leak Resulted in an Exceedance of Technical Specification 3.4.9 Condition A Limit for Pressurizer Level, LER 17-002-00 for Indian Point, Unit 3 re Manual Isolation of Chemical and Volume Control System Normal letdown to Stop a Valve Leak Resulted in an Exceedance of Technical Specification 3.4.9 Condition A Limit for Pressurizer Level 05000458/LER-2017-0062017-07-13013 July 2017 Potential Loss of Safety Function of Onsite Power Sources due to Inadvertent Inoperability of Control Building Chiller, LER 17-006-00 for River Bend, Unit 1 re Potential Loss of Safety Function of Onsite Power Sources due to Inoperability of Control Building Chiller 05000458/LER-2016-0032017-06-0808 June 2017 Operations Prohibited by Technical Specifications Due to Reactor Control Rod Drift During Core Alterations, LER 16-003-01 for River Bend Station, Unit 1, Regarding Operations Prohibited by Technical Specifications Due to Control Blade Drift During Core Alterations 05000458/LER-2017-0052017-06-0505 June 2017 1 OF 3, LER 17-005-00 for River Bend Station, Unit 1, Regarding Operations Prohibited by Technical Specifications Due to Inoperable Main Control Room Filter Train 05000458/LER-2017-0042017-05-22022 May 2017 Loss of High Pressure Core Spray Safety Function During Surveillance Due to Malfunction of Test Return Valve, LER 17-004-00 for River Bend Station, Unit 1, Regarding Loss of High Pressure Core Spray Safety Function During Surveillance Due to Malfunction of Test Return Valve 05000458/LER-2017-0032017-05-0909 May 2017 Manual Reactor Scram Initiated in Response to Increase in Steam Pressure During Steam Leak Troubleshooting, LER 17-003-00 for River Bend Station, Unit 1, Regarding Manual Reactor Scram Initiated in Response to Increase in Steam Pressure During Steam Leak Troubleshooting 05000458/LER-2017-0022017-04-18018 April 2017 Loss of Safety Function of Onsite Electrical Distribution Due to Malfunction of Control Building HVAC System, LER 17-002-00 for River Bend Station, Unit 1, Regarding Loss of Safety Function of Onsite Electrical Distribution Due to Malfunction of Control Building HVAC System 05000458/LER-2017-0012017-04-0303 April 2017 Operations Prohibited by Technical Specifications (Conduct of Operations With a Potential to Drain the Reactor Vessel With Primary Containment Open), LER 17-001-00 for River Bend Station, Unit 1, Regarding Operations Prohibited by Technical Specifications (Conduct of Operations With a Potential to Drain the Reactor Vessel With Primary Containment Open) 05000458/LER-2016-0072016-07-25025 July 2016 1 Operations Prohibited by Technical Specifications Due to Failure to Implement Required Actions Within Completion Time, LER 16-007-00 for River Bend Station, Unit 1, Regarding Operations Prohibited by Technical Specifications Due to Failure to Implement Required Actions Within Completion Time 05000458/LER-2016-0062016-07-12012 July 2016 Potential Loss of Safety Function of Multiple Systems Due to Design Deficiency in 480-volt Circuit Breakers, LER 16-006-00 for River Bend Station re: Potential Loss of Safety Function of Multiple Systems Due to Design Deficiency in 480-volt Circuit Breakers 05000336/LER-2016-0012016-06-27027 June 2016 Turbine Driven Auxiliary Feedwater Putnp Room HELB Door Left Open, LER 16-001-00 for Millstone Power Station Unit 2 RE: Turbine Driven Auxiliary Feedwater Pump Room HELB Door Left Open 05000423/LER-2016-0032016-06-0808 June 2016 Loss of Safety Function- Supplementary Leak Collection and Release System, LER 16-003-00 for Millstone Power Station, Unit 3, Regarding Loss of Safety Function-Supplementary Leak Collection and Release System 05000458/LER-2016-0042016-03-29029 March 2016 Actuation of the Division 1 Emergency Diesel Generator and Primary Containment Isolation Logic Due to Partial Loss of Offsite Power, LER 16-004-00 for River Bend, Unit 1, Regarding Actuation of the Division 1 Emergency Diesel Generator and Primary Containment Isolation Logic Due to Partial Loss of Offsite Power 05000458/LER-2016-0022016-03-0707 March 2016 Automatic Reactor Scram and Division 2 Primary Containment Isolation Due to Offsite Grid Electrical Transient, LER 16-002-00 for River Bend, Unit 1, Regarding Automatic Reactor Scram and Division 2 Primary Containment Isolation Due to Offsite Grid Electrical Transient 05000458/LER-2016-0012016-03-0707 March 2016 Potential Loss of Secondary Containment Safety Function Due to Failure of Auxiliary Building Ventilation System, LER 16-001-00 for River Bend, Unit 1, Regarding Potential Loss of Secondary Containment Safety Function Due to Failure of Auxiliary Building Ventilation System 05000458/LER-2015-0102016-02-0808 February 2016 Potential Loss of Safety Function of High Pressure Core Spray Due to Failure of Main Control Building Ventilation Chiller, LER 15-010-00 for River Bend Station, Unit 1, Regarding Potential Loss of Safety Function of High Pressure Core Spray Due to Failure of Main Control Building Ventilation Chiller 05000458/LER-2015-0092016-01-26026 January 2016 1 OF 3, LER 15-009-00 for River Bend Station, Unit 1 Regarding Automatic Reactor Scram Due to Partial Loss of Offsite Power Caused by Fault in Local 230K Switchyard 05000458/LER-2015-0072016-01-18018 January 2016 Potential Loss of Safety Function of High Pressure Core Spray Due to Failure of Main Control Building Ventilation Chiller, LER 15-007-00 for River Bend Station - Unit 1 Regarding Potential Loss of Safety Function of High Pressure Core Spray Due to Failure of Main Control Building Ventilation Chiller 05000458/LER-2015-0082016-01-18018 January 2016 Potential Loss of Safety Function of High Pressure Core Spray Due to Failure of Main Control Building Ventilation Chiller, LER 15-008-00 of River Bend Station, Unit 1, Regarding Loss of Safety Function of High Pressure Core Spray Due to Failure of Main Control Building Ventilation Chiller RBG-47473, Special Report for NEI 07-07 Notification2014-06-0404 June 2014 Special Report for NEI 07-07 Notification ML0627100382006-05-16016 May 2006 Final Precursor Analysis - River Bend Station, LER-458/04-005-01, Automatic Reactor Trip Due to Loss of Non-Vital 120V Instrument Bus 2017-08-09
[Table view] |
comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Infocollects.Resource@nrc.goy, and to the Desk Officer, Office of Information and Regulatory Affairs, 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.
05000-458 2017 009 00
REPORTED CONDITION
On September 27, 2017, at approximately 10:00 a.m. CDT, with the plant operating at 85 percent power, a door (**DR**) in the auxiliary building [NF] pressure boundary was left unsecured by an employee entering the building. The employee failed to fully close the door, and then did not properly challenge the door to confirm its security prior to leaving the area. A security officer responded to the resulting alarm, and fully closed the door approximately four minutes later.
This event is being reported in accordance with 10 CFR 50.73(a)(2)(v)(C) as an event that could have caused the loss of the safety function of the secondary containment pressure boundary.
BACKGROUND
The auxiliary building is part of the secondary containment pressure boundary. The event for which credit is taken for secondary containment is a loss of coolant accident. The secondary containment performs no active function in response to this event. However, its leak tightness is required to ensure that the release of radioactive materials from the primary containment is restricted to those leakage paths and associated leakage rates assumed in the accident analysis, and that fission products entrapped within the secondary containment structures will be treated prior to discharge to the environment.
The access doors in the auxiliary building pressure boundary have no redundancy. That is, each passageway contains only one door, not two doors in an airlock arrangement. As such, one unsecured door compromises the integrity of the pressure boundary.
CAUSAL ANALYSIS
The door was mis-operated by a contract worker with significant experience at River Bend, who had successfully traversed such doors in the past. The pre-job brief for the work to be performed in the auxiliary building did not include a specific discussion of secondary containment doors.
Four workers were traversing the door sequentially. The first worker swiped the card reader to open the door, and all the following workers swiped the card reader before entering the building to assure security accountability. The last person entering the door is responsible for closing it properly to secure the boundary. In this instance, the last person was being assisted by the previous worker who pulled on the door handle, while the last worker pulled on the door lock hand wheel. The worker pulling on the hand wheel inadvertently rotated it, causing the latch bolts to extend slightly.
The latch bolts contacted the door frame outside of their receivers, preventing the door from being closed completely.
Thinking that the door was properly closed, the worker holding the hand wheel rotated it fully, and the worker pulling the handle failed to notice that the door was not in contact with the seating surface in the frame. The worker then made an effort to assure the door's security by pushing in the open direction, but failed to move it. They then departed the area, leaving the door unsecured.
comments.regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to 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.
05000-458 2017 009 00 Since the worker had sufficient experience with watertight doors to know their proper operation, this event is considered a skill-based error caused by over-confidence and improper assumptions. Having successfully used such doors numerous times, the worker was confident in the ability to do so. The effort to check the door's security by pushing it failed, likely due to its heavy mass.
CORRECTIVE ACTION TO PREVENT RECURRENCE
The following actions have been completed to prevent a recurrence of this event. These actions are documented in the , station's corrective action program.
A briefing memorandum was issued from the general manager to site personnel.
Tamper alarms were installed on all watertight doors in the secondary containment boundary to provide an audible indication that the door is open. Administrative controls have been instituted to schedule routine battery replacements.
PREVIOUS OCCURRENCE EVALUATION
A similar event was reported by RBS in LER 050/458-2013-002-00. On September 19, 2013, at approximately 1437 CDT, with the plant operating at 100% power, the same door was left unsecured by an employee entering the auxiliary building. Upon closing the door, the employee mistakenly rotated the hand wheel while pulling on it, caused the latch bolts to extend partially. The latch bolts then contacted the door frame outside the receivers, blocking the door open slightly. The employee did not notice that the door was slightly open when he rotated the hand wheel to the "closed" position, and then did not properly challenge the door to confirm its security prior to leaving the area. A security officer responded to the resultant alarm, and fully closed the door approximately four minutes later. One of the corrective actions taken in response to that event was to update the computer-based training module used in the process for granting unescorted access to the site to include specific material related to the operation of watertight secondary containment doors. The skill-based error of failing to assure the security of the door occurred despite having successfully performed the task numerous times in the past. Both workers at the scene failed to adequately self-check their actions.
An additional corrective action in 2013 was to procure a commercially-available audible door tamper alarm that could be installed without any modification to the door itself, as well as other similar doors in the auxiliary building. These alarm modules were maintained for approximately two years, but no rigorous programmatic control was put into place at the time to assure their continued functionality, and the alarms modules were eventually removed.
SAFETY SIGNIFICANCE
The River Bend Updated Safety Analysis Report describes the sequence of events postulated to occur following a loss of coolant accident (LOCA). Part of that analysis is a projection of the maximum radiation dose received by a person at the site boundary. The LOCA dose calculation assumes that the standby gas treatment system is initiated 20 minutes into the event, and that secondary containment is at the required negative pressure within 30 minutes, such that filtration may be credited. As such, the safety function of secondary containment is maintained as long as the boundary is secured (or comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Inf ocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, 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 informatiort collection.
05000-458 2017 009 00 capable of being secured) within 20 minutes of the time of the security alarm. Since the subject door was secured within approximately four minutes of the time of the alarm, the safety function of secondary containment was actually maintained. This event was of minimal significance with respect to the health and safety of the public.
(NOTE: Energy Industry Identification System component function identifier and system name of each component or system referred to in the LER are annotated as (**XX**) and [XX], respectively.)