Semantic search
| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 41348 | 21 January 2005 05:53:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection (Hpci) Declared Inoperable Based on Inability to Verify Hpci Keep Fill Function Required by Technical Specifications | At 23:53 CST Unit 2 HPCI pump suction automatically transferred from the Condensate Storage Tank to the Suppression Pool. This caused HPCI to be declared inoperable due to not meeting Technical Specification Surveillance Requirement 3.5.1.1. HPCI keep fill could not be verified so HPCI was declared inoperable. This event is being reported pursuant to 10CFR 50.72(b)(3)(v) as 'Any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to: (D) Mitigate the consequences of an accident.' HPCI remains inoperable pending venting of the system. The licensee is conducting an investigation to determine the root cause for the automatic transfer. The licensee informed the NRC Resident Inspector. | High Pressure Coolant Injection | |
| ENS 43392 | 28 May 2007 06:00:00 | 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Hpci Pump Inoperable Due to Differential Pressure Setting Not within Specification | On 5/28/07 at 0100 CDT, Browns Ferry Unit 1 was performing 1-SR-3.5.1.7 (Comp) HPCI Comprehensive pump test when it was determined that HPCI pump set differential pressure was not within specifications and therefore would not support a declaration of operability for HPCI. The event is reportable under 10CFR 50.72(b)(3)(v)(B) - 'any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to remove residual heat' and 10CFR 50.72(b)(3)(v)(D) - 'any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident'. This event also requires a 60 day written report in accordance with 10CFR 50.72(b)(3)(v)(B) and 10CFR50.73(a)(2)(v)(D). Initial investigation reveals a potential problem with the test equipment. The licensee notified the NRC Resident Inspector.
This report is being retracted. Engineering has re-evaluated the test results and determined that HPCI System pump met its design basis requirements during testing activities. As such, the circumstance discussed in this event report did not result in any condition that could have prevented the fulfillment of the safety function of structures or systems needed to mitigate the consequences of an accident. Therefore, this event is not reportable under 10CFR50.72(b)(3)(v)(B) or 10CFR50.72(b)(3)(v)(D). The licensee notified the NRC Resident Inspector. R2DO (Ayres) notified. | ||
| ENS 43518 | 24 July 2007 21:45:00 | 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection Inoperable Due to Failed Power Supply | At 1645 on 7/24/07 during the transfer to the Normal Power Supply of the 3A 250 RMQV Board upon completion of scheduled maintenance. Unit 3 High Pressure Coolant Injection system received a 120 VAC Power Failure and was declared inoperable. 120VAC HPCI power is supplied by the Unit 3 ECCS Div 2 Analog Trip Unit Inverter. The Inverter lost power during the 250vdc board transfer and was not able to be restored to service. Investigation is still continuing on the failure of the Div 2 ECCS Inverter. This event is reportable as an 8-hour Non-Emergency Notification in accordance with 10 CFR 50.72 (b)(3)(v)(B) as; 'Any event or condition that at the time of discovery could have prevented the fulfillment of the Safety Function of structures or systems that are needed to: Remove Residual Heat' ; and 10 CFR 50.72 (b)(3)(v)(D), 'any event or condition that at the time of discovery could have prevented the fulfillment of the Safety Function of structures or systems that are needed to; mitigate the consequences of an accident.' This event also requires a 60 day written report in accordance with 10 CFR 50.73 (a)(2)(v)(B) and 10 CFR 50.73 (a)(2)(v)(D). NRC EVENT # 43518 was reported to Mr. Kozal and the NRC Resident (C. Stancil) was notified at 1925 CDST on 07/24/07. | High Pressure Coolant Injection | |
| ENS 43809 | 28 November 2007 08:30:00 | 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Hpci Inoperable Due to Level Switch Failure | On 11/28/2007 at 0230 CST, Browns Ferry Unit 1 received a 'HPCI PUMP SUCT HDR LEVEL LOW' alarm and HPCI automatically transferred its suction from the Condensate Storage Tank (CST) to the Suppression Pool. With the HPCI suction not aligned to its normal source, the HPCI system was declared inoperable. At 0710 CST, trouble shooting identified a level switch malfunction. This switch was removed from service allowing HPCl to be returned to the normal Standby Readiness configuration. The System was declared Operable at 0710 when the system was aligned back to normal suction source. This event is reportable under 10CFR 50.72(b)(3)(v)(B) 'any event or condition that at the time of discovery could have prevented the fulfillment of the Safety Function of structures or systems that are needed to: Remove Residual Heat' and 10CFR 50.72(b)(3)(v)(D) 'any event or condition that at the time of discovery could have prevented the fulfillment of the Safety Function of structures or systems that are needed to: mitigate the consequences of an accident.' This event also requires a 60 day written report in accordance with 10CFR 50.73(a)(2)(v)(B) and 10CFR 50.73(a)(2)(v)(D). The licensee notified the NRC Resident Inspector.
ENS Event Number 43809, made on 11/28/2007, is being retracted. NRC Notification 43809 was conservatively made to ensure that the eight-hour non-emergency reporting requirements of 10 CFR 50.72 were met pending the evaluation of an atypical system alignment with the High Pressure Coolant Injection (HPCI) (system). An evaluation has been performed in response to this event. The evaluation concluded that the HPCI system was capable of performing its intended safety function in this atypical configuration. As such, the circumstances discussed in the report did not result in any condition that could have prevented the fulfillment of the safety function of structures or systems needed to mitigate the consequences of an accident. Thus there would have no impact on nuclear safety. Therefore, this event is not reportable under 10 CFR 50.72(b)(3)(v)(B) or 10 CFR 50.72(b)(3)(v)(D). TVA's evaluation of this event is documented in the corrective action program. The licensee has notified the NRC Resident Inspector. Notified R2DO (Desai). | High Pressure Coolant Injection | |
| ENS 43815 | 30 November 2007 16:52:00 | 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Manual Hpci Isolation Due to Steam Leak Increase | At 1052 on 11/30/2007 while in Mode 3 for a maintenance outage, a previously identified steam leak on the packing of valve 3-FCV-073-0006A, HPCI Steam Line Condensate Inboard Drain Valve, increased. The room temperatures were not rising at the time of the increased leakage, alleviating the potential automatic isolation of the system. Upon review of the condition, the Operations staff closed the steam isolation valves and declared HPCI INOPERABLE to minimize the spread of contamination in the area. After HPCI was isolated, inspection of the valve identified a Code Class 2 piping through wall leak on a tee upstream of 3-FCV-073-0006A which contributed to the increased leakage observed prior to isolation of the system. This event is reportable as an 8-hour Non-Emergency Notification in accordance with 10CFR50.72 (b)(3)(v)(B) as; 'Any event or condition that at the time of discovery could have prevented the fulfillment of the Safety Function of structures or systems that are needed to: Remove Residual Heat'; and 10CFR50.72(b)(3)(v)(D), 'any event or condition that at the time of discovery could have prevented the fulfillment of the Safety Function of structures or systems that are needed to: mitigate the consequences of an accident.' This event also requires a 60 day written report in accordance with 10CFR 50.73(a)(2)(v)(B) and 10CFR 50.73(a)(2)(v)(D). The Code Class 2 piping leak was on a tee for the steam trap bypass valve upstream of the HPCI Steam Line Condensate Inboard Drain Valve. The licensee notified the NRC Resident Inspector. | ||
| ENS 43940 | 29 January 2008 00:43:00 | 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Core Injection (Hpci) Inoperable | On 1/28/08 at 1843 CST, Browns Ferry Unit 1 was performing 1-SR-3.3.5.1.3(D) HPCI System Condensate Header Low Level Switch Calibration and Functional Test when 1-LS-73-56A failed to actuate. Per TS 3.3.5.1, 1-LS-73-56A is inoperable. 1-SR-3.3.5.1.3(D) defeats the logic relay normally actuated by 73-56A & B. This causes HPCI to be inoperable per TS 3.3.5.1.D if the relay is defeated for greater than 1 hour. Failure of the 73-56A switch prevented restoration of the relay within the 1 hour time frame. This event is reportable under 10CFR 50.72(b)(3)(v)(B) 'any event or condition that at the time of discovery could have prevented the fulfillment of the Safety Function of structures or systems that are needed to: Remove Residual Heat' and 10CFR 50.72(b)(3)(v)(D) 'any event or condition that at the time of discovery could have prevented the fulfillment of the Safety Function of structures or systems that are needed to: mitigate the consequences of an accident.' This event also requires a 60 day written report in accordance with 10CFR 50.73(a)(2)(v)(B) and 10CFR 50.73(a)(2)(v)(D). The defeated relay was restored to normal and the HPCI system returned to operable status at 2330 CST on 1/28/08. The licensee notified the NRC Resident Inspector.
On January 28, 2008, Browns Ferry Unit 1 entered an LCO to perform a planned maintenance activity, High Pressure Coolant Injection System Condensate Header Low Level Switch Calibration and Functional Test, 1-SR-3.5.5.1.3(D). During the calibration of 1-LS-073-0056A and 1-LS-073- 0056B, 1-LS-073-0056A was found inoperable. The removal of both level switches from service (and as a result the HPCI transfer on low condensate header level function) was a planned maintenance activity, performed in accordance with an approved procedure and in accordance with the plants TSs. During this time no condition was discovered that could have prevented HPCI from performing its intended function because 1-LS-073-056B was considered OPERABLE. Therefore, this event is not reportable under 10 CFR 50.72(b)(3)(v)(B) or 10 CFR 50.72(b)(3)(v)(D). The licensee notified the NRC Resident Inspector. R2DO(Lesser) notified. | High Pressure Coolant Injection | |
| ENS 44252 | 1 June 2008 16:48:00 | 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Lube Oil Moisture Content Greater than Acceptable Limit | A sample was taken of the lubrication/control oil from the Unit 1 High Pressure Coolant Injection (HPCI) System for moisture content analysis. The results of this analysis concluded that the moisture content in the oil exceeded acceptable levels. As a result of this condition the Browns Ferry Nuclear Unit 1 HPCI system was declared inoperable at 11:48 on 6/1/08. This event is reportable within 8 hours in accordance with 10 CFR 50.72 (b)(3)(v) as event or condition that at the time of discovery could have prevented the fulfillment of a safety function. It also requires a 60 day written report in accordance with 10 CFR 50.73 (a)(2)(vii). Unit 1 remains at 100% power. Unit 1 has entered Technical Specification LCO 3.5.1 and is performing the required actions. Troubleshooting of the moisture intrusion condition is in progress, and a corrective action plan is being developed. The NRC Resident inspector has been notified.
ENS Event Number 44252, made on June 1, 2008, is being retracted. NRC Notification 44252 was conservatively made to ensure that the Eight-Hour Non-Emergency reporting requirements of 10 CFR 50.72 were met when an oil sample indicated the Unit 1 High Pressure Coolant Injection (HPCI) System turbine oil system contained excessive amounts of water. An evaluation performed in response to this report concluded that the Unit 1 HPCI System was capable of performing its intended safety function with the turbine oil system containing more water than recommended in the TVA Lubrication Oil Analysis and Monitoring Program. TVA found through an engineering evaluation that the amount of water contained in the turbine oil system would not impact the HPCI operation during its mission time for the Design Basis Loss-of-Coolant Accident. As such, the circumstances discussed in the report did not result in any condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to remove residual heat, or mitigate the consequences of an accident. Thus, there was no impact on nuclear safety. Therefore, this event is not reportable under 10 CFR 50.72(b)(3)(v)(B) or 10 CFR 50.72(b)(3)(v)(D). TVA's evaluation of this issue is documented in the corrective action program (PER 145517). The licensee has notified the NRC Resident Inspector. R2DO (Haag) notified. | High Pressure Coolant Injection | |
| ENS 44463 | 4 September 2008 04:43:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Failure of Dampers to Auto Close | Due to RPS A Circuit Protector surveillance testing, a transfer of 'A' Reactor Protection System from alternate power supply back to the 1A RPS MG-set was required. An expected group 6 containment isolation signal was received during the power transfer. Upon review of plant status to ensure systems responded as expected, it was determined that reactor ventilation zone exhaust dampers 1-DMP-64-42 and 1-DMP-64-43 (Inboard and Outboard Reactor Zone Exhaust Dampers) failed to auto-close. Isolation of these dampers is a required safety function. The dampers were administratively closed and deactivated in accordance with plant technical specification 3.6.4.2 action B. At the time of this report the cause for failure to auto close has not been determined. The licensee notified the NRC Resident Inspector. | Reactor Protection System | |
| ENS 44925 | 21 March 2009 09:06:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Unexpected Logic Lockout of Division I Rhr During Surveillance Testing | Operations was performing 1-SR-3.3.5.1.6(BI), Functional Testing of RHR Loop I Pump and Minimum Flow Valve Logic, which rendered Division I of RHR INOPERABLE. While placing a jumper in accordance with procedural direction. Unit 1 received RHR Pump Initiate Lockout amber lights 1-IL-74-28 and 1-IL-74-39 for 1B and 1D RHR pumps (Division II). This was immediately recognized as being unexpected and action was taken to restore the 1B and 1D RHR pump auto start capability. The 1B and 1D RHR pumps were prevented from auto starting for approximately 1 minute. The Logic functioned as designed; however, this condition was caused by a procedure error. Entered TS LCO 3.0.3 based on TS LCO 3.5.1 Condition H - Two or more Low pressure ECCS injection/spray subsystems inoperable for reasons other than Condition A. TS 3.0.3 was exited after approximately one minute when the auto start capability of 1B and 1D RHR pumps was restored. 1B and 1D RHR pumps were available for manual initiation and remained OPERABLE for Containment Cooling and Shut Down Cooling Functions. This event is reportable within 8 hours per 10CFR 50.72(b)(3)(v)(D) 'any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident.' The NRC resident inspector has been notified. At 0407, the condition requiring this report was removed and safety function capability was restored. | ||
| ENS 45227 | 24 July 2009 19:15:00 | 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Hpci Inoperable Due to Oil Leak in Mechanical Trip Hold Valve | During performance of surveillance 1-SR-3.5.1.7, HPCI Main and Booster Pump Set Developed Head and Flow Rate Test at Rated Reactor Pressure, the HPCI Turbine Stop Valve Mechanical Trip Hold Valve, 1-PCV-73-18C, developed an oil leak of approximately 0.25 gpm. HPCI was INOPERABLE at the time of discovery due to performance of SR and continued to be INOPERABLE due to the oil leak that developed. This event is reportable within 8 hours in accordance with 10CFR 50.72(b)(3)(v) as an event or condition that at the time of discovery could have prevented the fulfillment of a safety function. It also requires a 60 day written report in accordance with 10CFR 50.73(a)(2)(vii). The licensee notified the NRC Resident Inspector.
On July 24, 2009, the High Pressure Coolant Injection (HPCI) Stop Valve Mechanical Trip Hold Valve (PCV-073-0018C) developed a ruptured diaphragm resulting an approximate 0.25 to 0.5 gallon per minute oil leak during scheduled performance of Surveillance Instruction, HPCI Main and Booster Pump Set Developed Head and Flow Rate at Rated Reactor Pressure. At the time BFN (Browns Ferry Nuclear) made (event) notification 45227, there were concerns regarding the ability of HPCI to fulfill its safety function, hence, BFN made an eight hour notification in accordance with 10CFR50.72(b)(3)(v)(B) and 10CFR50.72(b)(3)(v)(D). An evaluation performed in response to this notification concluded that the HPCI System was capable of performing its intended safety function with the oil leak. TVA Engineering evaluated the rate of oil loss considering a worse case failure of PCV-073-0018C diaphragm and determined that the turbine oil system capacity is such that the oil loss thru the failed diaphragm would not impact HPCI operation during its mission time for the Design Basis accidents and transients for which HPCI is credited. The circumstances discussed in the notification did not result in any condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or system that are needed to remove residual heat and mitigate the consequences of an accident. Therefore, this event is not reportable under 10CFR50.72(b)(3)(v)(B) and 10CFR50.72(b)(3)(v)(D). TVA documented the evaluation of this event notification in its corrective action program (PER 177206). The licensee has notified the NRC Resident Inspector. Notified R2DO (Rudisail). | High Pressure Coolant Injection | |
| ENS 45320 | 1 September 2009 21:09:00 | 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection Inoperable | Unit 1 High Pressure Coolant Injection (HPCI) system was declared inoperable after the 250V RMOV BD breaker 11A1 for the ECCS DIV II Inverter tripped. The cause for the breaker trip is currently being investigated. This event is reportable within 8 hours in accordance with 10CFR 50.72(b)(3)(v) as an event or condition that at the time of discovery could have prevented the fulfillment of a safety function. It also requires a 60 day written report in accordance with 10CFR 50.73(a)(2)(vii). Unit 1 remains at 100% power. NRC Resident Inspector has been notified. | High Pressure Coolant Injection | |
| ENS 45494 | 12 November 2009 23:11:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Hpci Inoperable Due to Excessive Water in Steam Drain | The HPCI (High Pressure Coolant Injection) system was declared inoperable after completion of a scheduled surveillance due to an excessive amount of water in the turbine exhaust line. The line was being drained in response to the alarm 'HPCI TURB EXH DRAIN POT LEVEL HIGH', indicating that there was a high level in a drain pot attached to the turbine exhaust line. An investigation is in progress to determine the source of the water in the turbine exhaust line. This event is reportable within 8 hours in accordance with 10CFR 50.72(b)(3)(v) as an event or condition that at the time of discovery could have prevented the fulfillment of a safety function. It also requires a 60 day written report in accordance with 10CFR 50.73(a)(2)(vii) The NRC Resident Inspector has been notified. SR number associated with this report: 91546. | ||
| ENS 45505 | 18 November 2009 02:34:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Inadvertent Hpci Isolation | On 11/17/09 a 2034 (CST), while performing 2-SR-3.3.6.1.3(3DFT) HPCI Steam line space high temperature functional test, HPCI isolated due to B2 and A1 PCIS Channels picking up. A1 was the channel under test at the lime the isolation occurred. Following the immediate investigation it appears the isolation was due to test equipment configuration failure. This test equipment is still under investigation. This incident is reportable as an 8-hour ENS notification under 10CFR 5O.72 (b)(3)(v) as 'any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to: d. Mitigate the consequences of an accident.' It also requires a 60 day written report in accordance with 10CFR50.73(a)(2Xvii). The NRC Resident Inspector has been notified. SR number associated with this report: 93270. The HPCI system has been restored to operable status. | ||
| ENS 46019 | 16 June 2010 17:58:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection Inoperable | On 06/16/10 at 1320 CDT, while performing 2-SR-3.3.6.1.6(3), HPCI Time Delay Relay Calibration, HPCI was discovered to be isolated. After review of the Integrated Computer System (ICS), HPCI (steam supply valve) had isolated at 1258 CDT. Cause of isolation is unknown with investigation in progress. This incident is reportable as an 8-hour ENS notification under 10CFR 50.72 (b)(3)(v) as 'any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident.' It also requires a 60 day written report. The NRC Resident Inspector has been notified. | High Pressure Coolant Injection | |
| ENS 46087 | 12 July 2010 18:10:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Hpci Inadvertently Isolated During Testing | On 07/12/10 at 1310 CDT, while performing 2-SR-3.3.6.1.2(3B), High Pressure Coolant Injection (HPCI) System Steam Supply Low Pressure Functional Test, HPCI inadvertently isolated. The cause of isolation is unknown with an)investigation in progress. HPCI has been returned to standby readiness. This incident is reportable as an 8-hour ENS notification under 10CFR 50.72 (b)(3)(v) as any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident. It also requires a 60 day written report. The NRC Resident Inspector has been notified. | High Pressure Coolant Injection | |
| ENS 46870 | 21 May 2011 03:17:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Hpci Check Valve Leakage Results in System Leakage During Maintenance | On 5/20/2011 at 2217 (CDT), while performing 1-SR-3.5.1.1(HPCI) MAINTENANCE OF FILLED HPCI DISCHARGE PIPING, operators opened 1-FCV-73-44, HPCI Injection Valve, to fill and vent portions of the system. Once open, the HPCI discharge piping rapidly pressurized to 1000 psig. Operators immediately shut the 1-FCV-73-44 valve. A flood level alarm was received in the control room and water was confirmed to have been leaking from the Gland Seal Condenser. All leakage has stopped. It is suspected that leakage past 1-CKV-73-45, HPCI TESTABLE CHECK VALVE, caused the rise in discharge piping pressure. An investigation into this event is ongoing. In accordance with TS LCO 3.6.1.3 Condition A, the affected line has been isolated by one closed and deactivated valve. This incident is reportable as an 8-hour ENS notification under 10CFR 50.72 (b)(3)(v) as 'any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to: d. Mitigate the consequences of an accident.' It also requires a 60 day written report in accordance with 10CFR 50.73(a)(2)(vii). The NRC Resident Inspector has been notified. The volume of leakage was not specifically known but the leakage resulted in approximately 2 inches of water on the HPCI pump room floor before it was isolated. | ||
| ENS 47853 | 19 April 2012 19:30:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Hpci Failed Trip Testing Surveillance | On 04/19/12 at 1430 while performing 1-SR-3.5.1.7, HPCI (High Pressure Coolant Injection) Main & Booster Pump Set developed head & flow rate at rated reactor pressure. The HPCI turbine failed to trip using the manual trip pushbutton. This manual trip pushbutton should have caused the 1-FCV-73-18, HPCI TURBINE STOP VALVE, to go closed. HPCI was secured by taking the 1-FCV-73-16, HPCI TURBINE STEAM SUPPLY VALVE, to close. The 1-FCV-73-18, HPCI TURBINE STOP VALVE, also failed to go closed locally using the 1-XCV-73-18, HPCI TURBINE MECHANICAL TRIP, nor did it go closed when the auxiliary oil pump was secured. With the 1-FCV-73-18, HPCI TURBINE STOP VALVE, open, the HPCI ramp generator is no longer in the circuit therefore, should an initiation occur and cause the 1-FCV-73-16, HPCI TURBINE STEAM SUPPLY VALVE, to open there is the potential for the HPCI turbine to over speed. Therefore, HPCI was isolated using 1-FCV-73-3, HPCI STEAM LINE OUTBD ISOL VALVE. This incident is reportable as an 8-hour ENS notification under 10CFR 50,72 (b)(3)(v) as 'any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident.' It also requires a 60 day written report in accordance with 10CFR 50.73(a)(2)(vii). The NRC Resident Inspector has been notified. | ||
| ENS 48023 | 13 June 2012 22:45:00 | 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection System Declared Inoperable | On 6/13/12 at 1700 CDT, it was determined that valve 2-FCV-73-81 (HPCI steam line warm-up valve) was not capable of performing its intended primary containment isolation valve function. This determination was made during performance of a prompt determination of operability for a steam leak from a missing adapter on a Furmanite injection port in the valve packing area. To meet Technical Specification (TS) 3.6.1.3 action requirements for an inoperable primary containment isolation valve, 2-FCV-73-2 (HPCI inboard steam isolation valve) was closed at 1745 hrs., rendering U2 HPCI inoperable. As a result TS 3.5.1 actions were entered. This incident is reportable as an 8-hour ENS notification under 10CFR 50.72 (b)(3)(v)(B) and (D) as 'any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to remove residual heat and mitigate the consequences of an accident.' It also requires a 60 day written report in accordance with 10CFR 50.73(a)(2)(v)(B) and (D). The NRC Resident Inspector has been notified. This event has been entered into the Licensee's Corrective Action Program as SR 565729. Technical Specification 3.6.1.3 had a 4-hour shutdown action statement which was satisfied when the HPCI inboard steam isolation valve was closed. Technical Specification 3.5.1 action statement is a 14-day shutdown LCO. | High Pressure Coolant Injection Primary containment | |
| ENS 48200 | 17 August 2012 09:50:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Inadvertent Actuation of Primary Containment Isolation System | On 08/17/2012, while performing 2-SR-3.3.6.1(3DFT) - HPCI (High Pressure Coolant Injection) Steam Line Space Temperature Functional Test, an inadvertent PCIS (Primary Containment Isolation Signal) Group 4 (HPCI) isolation signal occurred. All automatic actions occurred as designed. Cause of the isolation is unknown with investigation in progress. This incident is reportable as an 8-hour ENS notification under 10 CFR 50.72 (b)(3)(v)(D). The incident also requires a 60 day written report. The NRC (Resident) Inspector has been notified. The steam supply valves to HPCI remain closed during trouble shooting and repair, however, HPCI remains available for use if needed. | Primary Containment Isolation System | |
| ENS 48467 | 31 October 2012 17:53:00 | 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Potentially Unable to Provide Power to Safe Shutdown Equipment During Appendix R Fire | During BFNP (Browns Ferry Nuclear Plant) NFPA (National Fire Protection Association) 805 transition review, it was determined in the event of an Appendix R fire, the ability to provide power to equipment needed to achieve and maintain safe shutdown may be adversely impacted. In certain fire zones/areas, feeder breakers for the 480V Shutdown Boards are credited for backup control operation using the 43 emergency switches, which isolate the breaker controls from circuits going to the control bay, and allow for local operation of the breaker. Fire damage to Main Control Room 480V Shutdown Board transfer switch cables could cause the control circuit fuses for the credited breaker to clear prior to the use of the 43 emergency switch. In addition, cable fire damage in the same fire areas could also cause the normal and/or alternate feeder breakers to spuriously trip. These breakers do not have separate emergency fuses like other BFNP breakers equipped with backup controls. Therefore, Safe Shutdown Instruction (SSI) procedure steps to use 43 switches to perform local breaker operation to supply power to safe shutdown equipment may not work as written where this cable fire damage can occur. Compensatory actions in the form of fire watches to mitigate this condition are in place in accordance with the BFNP Fire Protection Report. This condition is being reported pursuant to 10CFR50.72(b)(3)(ii)(B) and 10CFR50.72(b)(3)(v)(A),(B),(C).&(D). The NRC Resident Inspector has been notified. | ||
| ENS 49208 | 20 July 2013 09:38:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Hpci System Declared Inoperable | During performance of 1-SR-3.3.5.1.3(D), 'High Pressure Coolant Injection System Condensate Header Low Level Switch Calibration and Functional Test,' the High Pressure Coolant Injection (HPCI) system was declared inoperable due to exceeding the allotted 1 hour time frame for instrument inoperability of 1-LS-073-0056A and 1-LS-073-0056B (low condensate storage tank (CST) level HPCI suction transfer switches). The HPCI system was declared inoperable in accordance with technical specification (TS) 3.3.5.1 Condition D.1. Condition D of TS 3.3.5.1 is required to be entered during performance of this surveillance. The surveillance disables the automatic CST to Torus suction path transfer function of the HPCI system by booting relay contacts in order to perform a functional test of referenced switches. The 1 hour completion time of TS 3.3.5.1 required by action D.1 was exceeded due to issues with associated test equipment. This constitutes an unplanned HPCI system inoperability and requires an 8 hour NRC notification per 10CFR50.72(b)(3)(v)(D). HPCI remained available for automatic and manual injection during this time period. The HPCI system was declared inoperable at 0438 CDT on 7/20/13 and operability (CST to Torus suction transfer function) was restored at 0454 CDT on 7/20/13. The NRC resident inspector has been notified. The level switches (suction transfer switches) had been taken out-of-service for calibration and testing at 0338 CDT on 7/20/13. | High Pressure Coolant Injection | |
| ENS 49382 | 24 September 2013 20:30:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection System Declared Inoperable Due to an Unqualified Electrical Splice | On 9/24/13 at 1530 CDT, the Browns Ferry Nuclear Plant Unit 2 High Pressure Coolant Injection (HPCI) System was declared inoperable due to inoperability of the minimum flow valve (2-MVOP-073-0030). Engineering identified during review of EQ (Environment Qualification) WO (Work Order) # 113598388 that the motor leads for 2-MVOP-073-0030 were taped instead of terminated with a Raychem splice. The valve actuator is an EQ component and requires termination of the motor leads to the incoming power cable by Raychem splice or a Marathon 300 terminal block. Engineering evaluation was requested and operability of 2-MVOP-073-0030 could not be supported due to the tape being unanalyzed for harsh environmental conditions. The HPCI Minimum Flow valve has a required OPEN safety function to prevent overheating the HPCI pump and a CLOSED safety function to provide containment isolation. Technical Specification 3.5.1, Emergency Core Cooling System-Operating, Condition C was entered for HPCI system inoperability. In addition, the actions of Technical Specification 3.6.1.3, Primary Containment Isolation Valves, were entered due to the inoperability of the primary containment isolation function of the HPCI Minimum Flow valve. This incident is reportable as an 8-hour ENS notification under 10 CFR 50.72 (b)(3)(v)(D) as any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident. It also requires a 60 day written report in accordance with 10 CFR 50.73(a)(2)(vii). The NRC Resident Inspector has been notified. SR number associated with this report: 784462 The licensee is in a 14-day LCO action statement to return HPCI to operable under TS 3.5.1. The LCO for TS 3.6.1.3 was satisfied. | High Pressure Coolant Injection Primary containment | |
| ENS 49639 | 16 December 2013 23:00:00 | 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Potential for Spurious Start of Various Pumps During Postulated Fire Events | A circuit analysis review for Appendix R Operator Manual Action deficiency extent of condition identified that fire damage to cable ES194-I is not isolated by the local control power transfer switch utilized in the Safe Shut-down Instruction. Fire damage to the non-isolated cable ES194-I in Fire Areas 01-03, 02-01, and 02-03 could cause the RHR Pump 2C to spuriously start (or restart after the Operator local trip action) when 4kV Shutdown Board B is credited for these Fire Areas. An undesired spurious start of RHR Pump 2C could overload the credited Diesel Generator or take away the necessary load capacity to allow operation of other Appendix R fire safe shutdown credited loads. The fire damage postulated would require a short to ES194-I from a separate cable conductor energized with the positive potential of the battery supplying 4kV Shutdown Board B (i.e., normally Shutdown Battery B). It is postulated for a fire-event that the necessary short to ES194-I could come from a cable-to-cable short or from a short to ground as the fire event may cause a separate conductor energized with the positive potential of the associated battery to short to ground. Similar conditions also exist for: RHR Pumps 1A, 1B, 1D, 2A, 2B, 3A, and 3C due to fire damage to cables in one or more Fire Areas. Compensatory actions in the form of an Operator Work Around (OWA) to remove the affected RHR Pump breaker close circuit control power fuses during the affected Safe Shut-down Instructions, a caution order on the appropriate transfer switches referencing the OWA, and fire watches in the affected Fire Areas to mitigate this condition are in place in accordance with the BFNP (Browns Ferry Nuclear Plant) Fire Protection Report. This condition is being reported pursuant to 10CFR50.72(b)(3)(ii)(B) and 10CFR50.72(b)(3)(v). The NRC Resident Inspector has been notified. The licensee is also reporting under 10CFR50.72(b)(3)(v)(D) Accident Mitigation. | ||
| ENS 50129 | 21 May 2014 22:21:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Standby Liquid Control Inoperable Due to Tank Inleakage | On 5/21/2014 at 1721 CDT, BFN (Browns Ferry Nuclear) U2 declared both trains of standby liquid control (SLC) inoperable due to suspected in-leakage to the U2 SLC tank. Control Room Operators received an alarm for high tank level and corresponding high level on the control room indicator. Personnel were dispatched to check the tank level locally and reported that tank level was high and rising. Based on this report, the SLC tank isolation valve common to both pumps was closed to prevent potentially overflowing the tank. It was subsequently determined that the sensing line had become clogged causing erroneous level indication and the local report of level was incorrect. Sensing lines for the tank level instrumentation were subsequently cleared, indicated tank level then returned to normal, and local check verified that tank level was normal. Operability was restored with tank level being verified normal and isolation valve returned to the open position. This condition is being reported pursuant to 10 CFR 50.72(b)(3)(v)(C) and 10 CFR 50.72(b)(3)(v)(D). This is also reportable as a 60-day written report in accordance with 10 CFR 50.73(a)(2)(v)(C) and 10 CFR 50.73(a)(2)(v)(D). The NRC Resident Inspector has been notified of this event. | Standby Liquid Control | |
| ENS 50812 | 11 February 2015 14:20:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection System Suction Path Isolation | While performing 3-SR-3.5.1.2(HPCI) High Pressure Coolant Injection System Monthly Valve Position Verification, Operators closed the supply breaker for 3-FCV-2-166, CST #3 EMERGENCY HEADER ISOLATION VALVE, in order to verify the valve is in its required OPEN position. When the breaker was closed, the position indication 3-ZI-2-166 indicated OPEN and it was observed that the valve was traveling closed. The operator at the breaker reported that the breaker contactor energized when the breaker was closed. Control Room Operators re-opened 3-FCV-2-166 using the hand switch in the control room and when the valve indicated full open, directed the operator in the field to open the breaker for 3-FCV-2-166. Valve 3-FCV-2-166 isolates both the HPCI and (Reactor Core Isolation Cooling) RCIC suction path from the Condensate storage tank, both HPCI and RCIC were declared inoperable. The duration of the loss of suction path the HPCI and RCIC was 4 minutes. Applicable Technical Specification required actions were entered for the concurrent HPCI and RCIC inoperability and exited when the suction path was restored. This incident is reportable as an 8-hour ENS notification under 10 CFR 50.72 (b)(3)(v) as 'any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident.' It also requires a 60 day written report in accordance with 10 CFR 50.73(a)(2)(vii) The NRC Resident Inspector has been notified | High Pressure Coolant Injection | |
| ENS 51066 | 12 May 2015 06:04:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection Declared Inoperable | On May 12, 2015, at 0104 CDT, during performance of 3-SR-3.3.6.1.2(3B), High Pressure Coolant Injection (HPCI) System Steam Supply Pressure Low Functional Test, an inadvertent PCIS Group 4 (HPCI) isolation occurred. All automatic actions occurred as designed. HPCI was declared inoperable and Technical Specification LCO 3.5.1.C was entered with required action to verify immediately that RCIC is operable administratively and to restore HPCI to operable within 14 days. HPCI was returned to service at 0125 CDT, declared operable and TS LCO 3.5.1.C was exited. The cause of the isolation is unknown with an investigation in progress. This condition is reportable as an 8-hour ENS notification under 10CFR 50.72(b)(3)(v)(D) due to the failure of a single train system affecting accident mitigation. This condition also requires a 60 day written report. The NRC Resident Inspector has been notified. | High Pressure Coolant Injection | |
| ENS 51153 | 12 June 2015 15:30:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection Declared Inoperable | On June 12, 2015 at 1030 CDT, the Browns Ferry Nuclear Plant Unit 3 High Pressure Coolant Injection (HPCI) system was declared inoperable due to the time to drain the Turbine Exhaust Drain Pot after running the system for periodic testing. The concern is that the turbine may be partially flooded after shutting down and a subsequent restart could cause a water hammer event, possibly damaging the system. This issue was previously analyzed by Engineering as acceptable, but the time to drain the pot after the latest test indicates more water in the exhaust than the maximum amount used in the analysis. Technical Specification 3.5.1, ECCS Operating, Condition C, was entered as a result of the inoperable HPCI system. This constitutes an unplanned HPCI system inoperability and requires an 8-hour NRC notification in accordance with 10 CFR 50.72(b)(3)(v)(D) due to the failure of a single train system affecting accident mitigation, and a 60 day written report in accordance with 10 CFR 50.73(a)(2)(v) The NRC Resident Inspector has been notified. The Technical Specification Action statement allows 14 days to restore the HPCI system to operable status.
Browns Ferry Nuclear Plant is retracting the 8-hour NRC notification (EN# 51153) made on June 12, 2015 at 1030 CDT. The notification on June 12, 2015, reported a condition where the HPCI system was declared inoperable due to the time to drain the Turbine Exhaust Drain Pot after running the system for periodic testing. The concern was that the turbine may be partially flooded which could cause water hammer and damage the HPCI system. Subsequent evaluation concluded that the HPCI system under the identified flooded turbine conditions will not produce a transient that exceeds design values, therefore, HPCI system operability was maintained and no reportable condition existed during this time. The NRC Resident Inspector has been notified of this retraction. Notified R2DO (Shaeffer). | High Pressure Coolant Injection | |
| ENS 51250 | 22 July 2015 09:45:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Hpci Declared Inoperable | During the performance of the Unit 1 quarterly surveillance 1-SR-3.6.1.3.5 (HPCI), HPCI (High Pressure Coolant Injection) System Motor Operated Valve Operability, the inboard steam isolation valve failed to close within the required time. The valve was subsequently declared inoperable and Technical Specification (TS) Limiting Condition for Operation (LCO) 3.6.1.3 (Primary Containment Isolation Valves (PCIVs)) was entered which required the HPCI steam line to be closed and de-activated. To comply with TS LCO 3.6.1.3 Condition A, the outboard steam isolation valve was closed and breaker opened. Due to the steam line being isolated, TS 3.5.1, ECCS Operating, Condition C was entered on July 22, 2015 at 0445 CDT as a result of the inoperable HPCI system. Troubleshooting and repair is in progress and during this inoperability, other systems are available to provide the required safety functions. This constitutes an unplanned HPCI system inoperability and requires an 8-hour ENS notification in accordance with 10 CFR 50.72(b)(3)(v)(D), due to the failure of a single train system affecting accident mitigation, and a 60-day written report in accordance with 10 CFR 50.73(a)(2)(v)(D). The NRC Resident Inspector has been notified. | Primary containment | |
| ENS 51398 | 16 September 2015 07:00:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection System Declared Inoperable Due to Valve Stem Packing Steam Leak | At 0200 CDT on 9/16/2015, the High Pressure Coolant Injection (HPCI) System was manually isolated to stop a steam leak from the stem packing of the HPCI Steam Supply Valve 2-FCV-073-0016. The leak occurred following performance of 2-SR-3.6.1.3.5 (HPCI) HPCI System Motor Operated Valve Operability, which cycled 2-FCV-073-0016. No Area Radiation Monitoring (ARM) or PCIS Area High Temperature alarms were received and no automatic isolation setpoints were reached. HPCI was declared inoperable per Technical Specification (TS) Limiting Condition for Operation (LCO) 3.5.1 Emergency Core Cooling Systems (ECCS)- Operating, Condition C. This constitutes an unplanned HPCI system inoperability and requires an 8-hour ENS notification in accordance with 10 CFR 50.72(b)(3)(v)(D), due to the failure of a single train system affecting accident mitigation, and a 60-day written report in accordance with 10 CFR 50.73(a)(2)(v)(D). The NRC resident inspector has been notified. | High Pressure Coolant Injection Emergency Core Cooling System | 05000260/LER-2015-002 |
| ENS 51996 | 8 June 2016 15:37:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection Inoperable | At 0800 CDT on 6/8/2016, 3-SR-3.5.1.7, 'HPCI (High Pressure Coolant Injection) Main and Booster Pump Set Developed Head and Flow Rate Test at Rated Reactor Pressure' periodic surveillance was being performed. As part of the surveillance procedure, HPCI was declared inoperable per Technical Specification (TS) Limiting Condition for Operation (LCO) 3.5.1 Emergency Core Cooling Systems (ECCS) - Operating, Condition C at 0925. At 1037, the HPCI turbine was started and a turbine trip alarm was received as well as large swings observed on the suction pressure indicator and slow turbine response. The control room operator then manually tripped the HPCI turbine due to the abnormal indications received. HPCl is a single train safety system and this notification is being made in accordance with 10 CFR 50.72 (b)(3)(v)(D). The NRC Resident Inspector has been notified. | High Pressure Coolant Injection Emergency Core Cooling System | |
| ENS 52019 | 18 June 2016 02:35:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection System Rendered Inoperable | On 6/17/2016, 2-SR-3.3.6.1.6(3) HPCI (High Pressure Coolant Injection) system time delay relay calibration periodic surveillance was being performed. During a section in the procedure a fuse cleared for the logic bus B power at 2135 (CDT). This rendered the HPCI system unable to be manually or automatically initiated. At 2239 the fuse was replaced and the HPCI system was restored to a standby lineup. HPCl is a single train safety system and this notification is being made in accordance with 10CFR50.72 (b)(3)(v)(D). The NRC Resident Inspector has been notified. | High Pressure Coolant Injection | |
| ENS 52113 | 20 July 2016 17:45:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection Inoperable | On 07/20/2016 at 1245 CDT, the Browns Ferry Nuclear Plant Unit 1 High Pressure Coolant Injection (HPCI) Steam Line Inboard Isolation Valve was declared inoperable. HPCI was declared inoperable at 0300 CDT on 7/18/2016 when it was taken out of service for planned maintenance. A 14 day LCO (Limiting Conditions for Operation) was entered and will expire at 0300 CDT on 8/1/2016. HPCI was being returned to service after the planned maintenance period. The inboard isolation valve and the bypass around the outboard isolation valve were open to warm and pressurize the HPCI steam line. HPCI steam line pressure stabilized at approximately 50 psig. The outboard isolation valve was slowly opened to determine if the inboard isolation valve was actually open. There was no change in steam line pressure or indications of flow at the valves. Based on this information, the HPCI Steam Line Inboard Isolation Valve was declared inoperable for its Primary Containment Isolation function. The appropriate Technical Specification Limiting Conditions for Operation (LCOs) were entered and the HPCI steam line was isolated. This constitutes an unplanned HPCI system inoperability and requires an 8 hour ENS notification in accordance with 10 CFR 50.72(b)(3)(v)(D), due to the failure of a single train system affecting accident mitigation and a 60 day written report in accordance with 10 CFR 50.73(a)(2)(v)(D). The Senior NRC Resident Inspector has been notified. | High Pressure Coolant Injection Primary containment | 05000259/LER-2016-002 |
| ENS 52557 | 16 February 2017 16:52:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Hpci System Inoperable Due to Blown Fuse | On February 16, 2017 at 1052 CST, Unit 2 received a High Pressure Coolant Injection (HPCI) System 120V Power Failure alarm. Troubleshooting identified a cleared fuse for the HPCI System Flow Controller, 2-FIC-73-33, which would have prevented automatic or manual HPCI System initiation and rendered the HPCI System inoperable. At 1145 CST, the cleared fuse was replaced and the HPCI system was declared available. The HPCI System remains inoperable for additional troubleshooting. This constitutes an unplanned HPCI System inoperability and requires an 8 hour ENS notification in accordance with 10 CFR 50.72(b)(3)(v)(D), due to the failure of a single train system affecting accident mitigation and a 60 day written report in accordance with 10 CFR 50.73(a)(2)(v)(D). The Senior NRC Resident Inspector has been notified. | High Pressure Coolant Injection | |
| ENS 52959 | 10 September 2017 16:51:00 | 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Two Control Bay Chillers Declared Inoperable | At 1151 (CDT) on September 10, 2017 Browns Ferry Units 1 and 2 declared 'B' Control Bay chiller inoperable. 'A' Control Bay chiller was previously declared inoperable. This resulted in inoperability of the equipment in the U1 and U2 4kV Shutdown Board Rooms. The declarations of the equipment in the Shutdown Board Rooms is a loss of safely function for electrical components (4kv Shutdown Boards and 480V Shutdown Boards) required for shut down of the U1 and U2 reactors and maintaining them in a safe shutdown condition, as well as RHR capability and Accident Mitigation. lnoperability of these boards also requires declaring two trains of Standby Gas Treatment inoperable resulting in a loss of safety function for Units 1, 2 and 3 for systems needed to control the release of radioactive material. This event requires an 8 hour report IAW 50.72(b)(3)(v), 'Any event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to (A) Shut down the reactor and maintain it in a safe shutdown condition; (B) Remove residual heat; (C) Control the release of radioactive material; or (D) Mitigate the consequences of an accident. The NRC Resident Inspector has been notified. CR 1336821 was initiated in the Browns Ferry Corrective Action Program. | ||
| ENS 53014 | 13 October 2017 22:00:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Accident Mitigation - High Pressure Coolant Injection Declared Inoperable | On October 13, 2017 at 1700 CDT, Unit 1 High Pressure Coolant Injection (HPCI) was declared Inoperable due to discovery of a leak on a sensing line to 1-PCV-073-0043, Lube Oil Cooler & Gland Seal Condenser Pressure Control Valve. The leak is a steady stream located where the sense line connects to the valve. This constitutes an unplanned HPCI System inoperability and requires an 8 hour ENS notification in accordance with 10 CFR 50.72(b)(3)(v)(D), due to the failure of a single train system affecting accident mitigation and a 60 day written report in accordance with 10 CFR 50.73(a)(2)(v)(D). The NRC Resident Inspector has been notified by the Licensee. | High Pressure Coolant Injection | |
| ENS 53340 | 17 April 2018 09:16:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection System Inoperable | At 0416 CDT on April 17, 2018, the High Pressure Coolant Injection System (HPCI) was isolated due to a water side leak from the gland seal condenser. Unit 1 HPCI remains inoperable pending repairs to the gland seal condenser. This condition is being reported pursuant to 10 CFR 50.72(b)(3)(V)(D), 'Any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident.' This is also reportable as a 60-day written report in accordance with 10 CFR 50.73(a)(2)(V)(D). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified of this event. | High Pressure Coolant Injection | |
| ENS 53497 | 9 July 2018 05:00:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection System Declared Inoperable | On 07/09/2018 at 1111 CDT, Browns Ferry Unit 1 Operators identified U1 High Pressure Cooling Injection system steam supply valves were isolated. After reviewing ICS (Integrated Computer System), Operations determined isolation occurred at 0958 CDT during performance of surveillance testing. The Browns Ferry Nuclear Plant Unit 1 High Pressure Coolant Injection (HPCI) system was declared inoperable at 0958 CDT due to an inadvertent isolation that occurred during testing. During performance of surveillance procedure 1-SR-3.3.6.1.2(3B) HPCI System Steam Supply Low Pressure Functional test, an erroneous signal was induced causing actuation of primary containment isolation system group IV (i.e., HPCI Isolation). Technical Specification 3.5.1, ECCS-Operating, Condition C was entered as a result of the inoperable HPCI system. This constitutes an unplanned HPCI system inoperability and requires an 8-hour NRC notification in accordance with 10 CFR 50.72(b)(3)(v)(D). The erroneous signal was cleared and the HPCI isolation was reset. Upon reset of the isolation signal, the HPCI system was returned to available status. The HPCI system was unavailable for 2 hours and 55 minutes, however the HPCI system remains inoperable. There was no impact to the health and safety of the public or plant personnel as a result of this condition. The NRC Resident Inspector has been notified. A condition report has been entered into the Licensee's Corrective Action Program to capture this event. | High Pressure Coolant Injection Primary Containment Isolation System | |
| ENS 53750 | 21 November 2018 06:00:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | En Revision Imported Date 12/31/2018 | EN Revision Text: HPCI UNEXPECTEDLY TRANSFERRED TO ALTERNATE SUCTION SOURCE DURING TESTING At 2125 (CST) on 11/21/2018, it was discovered that U1 High Pressure Coolant Injection System (HPCI) was inoperable; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v), as an event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident. During performance of a routine surveillance, HPCI automatically transferred from its normal suction source to the alternate suction source. The control room operator then manually tripped the HPCI turbine. HPCI was already inoperable in accordance with Technical Specifications (TS) Limiting Condition for Operability (LCO) 3.5.1, ECCS Operating, Condition C during performance of the surveillance. However, this condition was not expected nor induced by the testing. There was no impact to the safety of the public or plant personnel. The NRC Resident Inspector has been notified. CR 1469109 documents this condition in the Corrective Action Program.
ENS Event Number 53750, made on November 22, 2018, is being retracted. NRC notification 53750 was made to ensure that the Eight-Hour Non-Emergency reporting requirements of 10 CFR 50.72(b)(3)(v)(D) were met when the licensee discovered an event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident. During performance of a routine surveillance, the High Pressure Coolant Injection (HPCI) System automatically transferred from its normal suction source to the alternate suction source. As a result, Unit 1 HPCI was declared inoperable. On December 20, 2018, a Past Operability Evaluation was completed which determined that the HPCI System remained operable. The evaluation determined that the HPCI System could have performed its specified safety function of vessel injection throughout the time that the suction path was aligned to the torus. Therefore, this event is not reportable under 10 CFR 50.72(b)(3)(v)(D). TVA's evaluation of this event is documented in the Corrective Action Program in Condition Report 1469109. The licensee has notified the NRC Resident Inspector. Notified R2DO (Desai). | High Pressure Coolant Injection | |
| ENS 53942 | 17 March 2019 12:35:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | En Revision Imported Date 4/24/2019 | EN Revision Text: HIGH PRESSURE COOLANT INJECTION SYSTEM DECLARED INOPERABLE At 0735 CDT on March 17, 2019, the High Pressure Coolant Injection (HPCI) system was isolated due to a water-side leak from the HPCI Gland Seal Condenser. Unit 3 declared the HPCI system Inoperable and entered Technical Specification LCO 3.5.1 Condition C with required actions to verify the Reactor Core Isolation Cooling system is Operable, and to restore the HPCI system to Operable status within 14 days. All other Unit 3 Emergency Core Cooling Systems (ECCS) remain Operable. This condition is being reported pursuant to 10 CFR 50.72(b)(3)(V)(D), 'Any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident.' This is also reportable as a 60-day written report in accordance with 10 CFR 50.73(a)(2)(V)(D). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified of this event.
ENS Event Number 53942, made on March 17, 2019, is being retracted. NRC Notification 53942 was made to ensure that the Eight-Hour Non-Emergency reporting requirements of 10 CFR 50.72 (b)(3)(v)(D) were met when the licensee discovered an event, that at the time of discovery, could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident. At 0735 CDT, on March 17, 2019, during the performance of a routine surveillance, a momentary pressure transient of 844 psig from the Feedwater system was introduced into the High Pressure Coolant Injection (HPCI) system discharge and suction piping that ruptured the seal on the gland seal condenser and flooded the U3 HPCI Room. Unit 3 HPCI was declared inoperable due to isolation of the waterside of the HPCl system. On April 11, 2019, a Past Operability Evaluation was completed which determined that the HPCI System remained operable. The evaluation of the potential pressure transient and room flooding concluded that the HPCI System could have performed its specified safety function of vessel injection throughout the time that the gland seal was ruptured. Therefore, this event is not reportable under 10 CFR 50.72(b)(3)(v)(D). TVA's evaluation of this event is documented in the Corrective Action Program in Condition Report 149973. The licensee has notified the NRC Resident Inspector. Notified R2DO (Ehrhardt). | Feedwater High Pressure Coolant Injection Reactor Core Isolation Cooling Emergency Core Cooling System | |
| ENS 54162 | 12 July 2019 21:40:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Invalid Auto Isolation Signal of High Pressure Coolant Injection | At 1640 CDT on 7/12/19, Unit 1 High Pressure Coolant Injection (HPCI) received an invalid auto isolation signal which closed the HPCI steam supply valves rendering HPCI inoperable. This condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D), as an event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident. The isolation occurred while performing a calibration and functional check of a level switch for the Unit 1 Core Spray system. Continuity was checked across the incorrect set of contacts which completed the circuit in logic bus 'A' for the auto isolation signal in the HPCI system. There was no impact to the safety of the public or plant personnel during the time HPCI system was isolated. HPCI was returned to operable at 2110 CDT on 7/12/19. CR 1532094 documents this condition in the Corrective Action Program. The licensee has notified the NRC Resident Inspector | High Pressure Coolant Injection Core Spray | |
| ENS 54983 | 5 November 2020 03:50:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection Inoperable | At 2150 CST on 11/04/2020, it was discovered that Unit 1 High Pressure Coolant Injection System (HPCI) was INOPERABLE; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v), as an event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident. During performance of 1-SR-3.5.1.7, HPCI Main and Booster Pump Set Developed Head and Flow Rate Test at Rated Reactor Pressure, Unit 1 HPCI was manually tripped by the control room operator due to local report of excessive shaking of the cooling water supply from the booster pump line. There was no impact to the safety of the public or plant personnel. The NRC Resident Inspector has been notified. CR 1650042 documents this condition in the Corrective Action Program. The Unit is in a 14-day LCO 3.5.1(c). The RCIC System is operable.
ENS Event number 54983, made on 11/05/2020 is being retracted. NRC notification 54983 was made to ensure that the Eight-Hour Non-Emergency reporting requirements of 10 CFR 50.72 were met when Unit 1 HPCI was manually tripped by the control room operator due to a local report for excessive shaking of the cooling water supply from the booster pump line. A subsequent engineering evaluation concluded on 11/06/2020 there was reasonable assurance of operability with no additional intrusive maintenance performed and that the condition was bounded by a previous evaluation documented in (Condition Report) CR 1347736. As such, the circumstances discussed in the report did not result in any condition that at the time of discovery could have prevented the fulfillment of the safety function of structures of the system that are needed to mitigate the consequences of an accident. Therefore, this event is not reportable under 10 CFR 50.72(b)(3)(v). TVA's evaluation of this event is documented in the corrective action program. The licensee has notified the NRC Resident Inspector. Notified R2DO (Miller). | High Pressure Coolant Injection | |
| ENS 55992 | 12 July 2022 14:17:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection Inoperable | The following information was provided by the licensee via fax or email: At 0917 CDT on 7/12/2022, during the performance of U1 (Unit 1) High Pressure Coolant Injection (HPCI) rated flow test, the 1-FCV-73-19 (HPCI governor valve) failed to operate as expected. This condition results in U1 HPCI being inoperable; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v). The Automatic Depressurization System (ADS) and Reactor Core Isolation Cooling (RCIC) system remain operable. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. U1 entered TS LCO 3.5.1 Condition C, 14-day Shutdown LCO (Limiting Condition for Operation), due to the HPCI inoperability. | High Pressure Coolant Injection Reactor Core Isolation Cooling Automatic Depressurization System | |
| ENS 56168 | 18 October 2022 19:40:00 | 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Standby Liquid Control Inoperable | The following information was provided by the licensee via email: On 10/18/2022 at 1440 CDT, Browns Ferry Unit 3 declared both trains of standby liquid control (SLC) inoperable due to acceptance criteria failure of 3-SI-3.1.7.6, 'Standby Liquid Control System ATWS Equivalency Calculation for Newly Established Pump Flow Rate.' The purpose of this surveillance is to ensure the anticipated transient without scram (ATWS) calculation criteria is met after each pump flow test. Chemistry performed the surveillance following pump flow testing and the requirement for equivalency calculation failed low with a result of less than 1.0. CR 1810303 documents this condition in the corrective action program. This condition is being reported pursuant to 10 CFR 50.72(b)(3)(v)(A), 10 CFR 50.72(b)(3)(v)(C), and 10 CFR 50.72(b)(3)(v)(D). This condition is also reportable as a 60-day written report in accordance with 10 CFR 50.73(a)(2)(v)(A),10 CFR 50.73(a)(2)(v)(C), and 10 CFR 50.73(a)(2)(v)(D). The NRC Resident Inspector has been notified of this event. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officer's report guidance: The plant entered an 8 hour limiting condition for operation based on the above. The condition was resolved at 2053 CDT when the system was restored to normal operation. | Standby Liquid Control | |
| ENS 56321 | 24 January 2023 07:21:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection Inoperable | The following information was provided by the licensee via email: At 0121 CST on 01/24/2023, it was discovered that the Unit 1 High Pressure Coolant Injection System (HPCI) was inoperable; therefore, the condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v), as an event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident. 1-FCV-073-0006B, HPCI Steam Line Condensate Outboard Drain Valve, failed closed during normal plant configuration. This valve is normally open. The HPCI steam line is not being drained with the valve in the current position. The Unit 1 Nuclear Unit Senior Operator entered Unit 1 Technical Specifications LCO 3.5.1 Condition C with required actions C.1 to immediately verify by administrative means that the Reactor Core Isolation Cooling (RCIC) system is operable and C.2 to restore HPCI to operable status in 14 days. RCIC has been verified operable by administrative means. There was no impact to the safety of the public or plant personnel. The NRC Resident Inspector has been notified. | High Pressure Coolant Injection Reactor Core Isolation Cooling | |
| ENS 57036 | 19 March 2024 15:30:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | High Pressure Coolant Injection Isolation | The following information was provided by the licensee via fax or email: While performing a planned high pressure coolant injection (HPCI) system surveillance, an isolation signal was received based upon an exhaust rupture disc high pressure signal. This resulted in an unplanned inoperability of the HPCI system. All systems responded as expected, and the event is under investigation. No other systems were affected by this condition. This event is reportable as an 8-hour non-emergency notification under 10CFR50.72(b)(3)(v) as HPCI is a single train safety system. There was no impact to plant personnel or the public as a result of this condition. The NRC resident has been notified of this condition. | High Pressure Coolant Injection |