05-09-2017 | On March 10, 2017, at approximately 7:14 a.m. CST, the reactor operator manually actuated a reactor scram in response to an abnormal increase in steam pressure. Reactor power was approximately 15 percent at the time. The turbine generator had been synchronized to the grid at 5:13 a.m. on March 10, and was being closely monitored by engineers and operators since a major modification to the turbine electro-hydraulic control ( EHC) system had been installed during the recent refueling outage.
Approximately 45 minutes prior to the manual scram, a main control room alarm actuated indicating a problem with the EHC system.
A few minutes later, it was reported from the turbine building that there was a steam leak in the area of the EHC steam pressure transmitters. Shortly thereafter, reactor pressure began to increase with no demand signal present, at which time the reactor operator initiated the scram. The main feedwater system remained in service, and reactor water level control performed normally as designed. No reactor safety-relief valves actuated. The main turbine bypass valves did not open following the shutdown, and engineering review determined this condition was consistent with the response to the abnormal configuration of the EHC system pressure transmitters created by efforts to isolate the leak locally. Approximately five minutes after the scram, the outboard main steam isolation valves were manually closed to limit the reactor cooldown rate. This event resulted from the incorrect installation of a new compression fitting in the steam pressure instrumentation tubing for the main turbine control system. This event is being reported in accordance with 10 CFR 50.73(a)(2)(iv)(A) as a manual actuation of the reactor protection system. |
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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 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 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 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 ML23310A0322023-11-13013 November 2023 Integrated Inspection Report 05000458/2023003 IR 05000458/20230032023-11-13013 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 ML23117A2172023-05-0101 May 2023 Safety Evaluation for Quality Assurance Program Manual Reduction in Commitment ML23116A2352023-05-0101 May 2023 Integrated Inspection Report 05000458/2023001 RBG-48220, Submittal of 2022 Annual Radioactive Effluent Release Report2023-04-25025 April 2023 Submittal of 2022 Annual Radioactive Effluent Release 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 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 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-2015-0082016-01-18018 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 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 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 2017-08-21
[Table view] |
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05000-458 2017 003 00
REPORTED CONDITION
On March 10, 2017, at approximately 7:14 a.m. CST, the reactor operator manually actuated a reactor scram in response to an abnormal increase in steam pressure. Reactor power was approximately 15 percent at the time, and the turbine generator was on line. The reactor had been taken critical at 4:39 p.m. on March 8 following a refueling outage, and power ascent was in progress. The turbine generator had been synchronized to the grid at 5:13 a.m. on March 10, and was being closely monitored by engineers and operators since a major modification to the turbine electro-hydraulic control (EHC) system [JI] had been installed during the outage.
Approximately 45 minutes prior to the manual scram, a main control room alarm actuated indicating a problem with the EHC system. A few minutes later, it was reported from the turbine building that there was a steam leak in the area of the steam pressure transmitters. The operations shift manager held a briefing with the operators on potential effects of the field observations, the single-point vulnerability of the transmitter configuration, and the possibility of a main turbine trip. Shortly thereafter, reactor pressure began to increase with no demand signal present. This response likely resulted from efforts to isolate the steam leak.
The main feedwater system remained in service, and reactor water level control was performed normally. No reactor safety-relief valves actuated. The main turbine bypass valves did not open following the shutdown, and engineering review determined this condition was consistent with the response to the abnormal configuration of the EHC system pressure transmitters created by efforts to isolate the leak locally. Approximately five minutes after the scram, the outboard main steam isolation valves were manually closed to limit the reactor cooldown rate.
Other than scheduled testing on the Division 1 diesel generator, no safety-related systems were out of service at the time of the scram.
This event is being reported in accordance with 10 CFR 50.73(a)(2)(iv)(A) as a manual actuation of the reactor protection system
INVESTIGATION
During the recent refueling outage, a digital control system had been installed on the main steam turbine bypass / pressure regulation system. Part of that modification involved the installation of a new main turbine steam throttle pressure transmitter (**PT**) near the high pressure turbine. The transmitter was to be installed adjacent to two existing steam pressure transmitters by adding a tee fitting into an existing run of tubing (**TBG**). One of the newly- installed tubing compression fittings separated during efforts to isolate the leak. Examination of the components concluded that the ferrule in the fitting was not fully inserted, and did not compress adequately to engage the surface of the tubing when the nut was tightened.
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 003 00 The tee fitting was installed by two qualified pipefitters who were contracted for the refueling outage, with oversight provided by a contract pipefitter foreman. The field work to complete the fit-up of the tee connection was specified as Quality Control (QC) Hold Point. The contract foreman stated that he was present during the fit-up of the tee connection and that the technicians performed the work as required, fitting each of the three connections and tightening them one at a time starting with the top compression fitting and ending with the bottom connection. When the fittings were tight, he observed the technicians use a gap tool to verify proper gap and engagement of the compression nut on the tee connection body.
CAUSAL ANALYSIS
This event resulted directly from the incorrect installation of the tee compression fitting for the new steam pressure transmitter. A contributing cause was the lack a standard process on how to properly verify compression tubing and fitting engagement is maintained during the tightening process.
CORRECTIVE ACTION TO PREVENT RECURRENCE
A maintenance procedure will be developed to address the proper installation of compression fittings. This action will be tracked in the corrective action program.
PREVIOUS OCCURRENCE EVALUATION
RBS has reported no similar events in the last three years.
SAFETY SIGNIFICANCE
The plant responded as designed to the transient. The response of the main turbine bypass valves resulted from the efforts to isolate the steam leak, and was, by itself, of no consequence to the operators' response to the event. The steam leak was isolated by closure of an instrument valve. The outboard main steam isolation valves were manually closed in accordance with procedures to manage reactor cooldown rate. There were no injuries as a result of the steam leak. This event was, thus, of minimal significance 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.)
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05000458/LER-2017-001 | 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) | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000458/LER-2017-002 | 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 | 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), Loss of Safety Function | 05000458/LER-2017-003 | 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 | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000458/LER-2017-004 | 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 | 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material | 05000458/LER-2017-005 | 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 | 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 | 05000458/LER-2017-006 | 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 | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | 05000458/LER-2017-007 | 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 | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000458/LER-2017-009 | 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 | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material |
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