Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 56321 | 24 January 2023 08:43:00 | 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. |
| ENS 50129 | 22 May 2014 02:02:00 | 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. |
| ENS 48421 | 18 October 2012 18:57:00 | 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, fire induced circuit damage could potentially result in the Residual Heat Removal System Division II inboard isolation valve being prevented from opening or cause the valve to spuriously close on units 2 and 3. The current Appendix R safe shutdown analysis credits opening of these valves. Failure to open these valves results in loss of ability to provide long term cooling to the core. 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). The NRC Resident Inspector has been notified. |
| ENS 48419 | 18 October 2012 13:34:00 | A non-licensed contract supervisor had a confirmed positive for alcohol during a for-cause fitness-for-duty test. The contractor's access to the plant has been suspended. Contact the Headquarters Operations Officer for additional details. The NRC Resident Inspector has been notified. |
| ENS 47450 | 17 November 2011 13:53:00 | This 60-day telephone notification is being made per the reporting requirements specified by 10 CFR 50.73(a)(2)(iv)(A) and 10 CFR 50.73(a)(1) to describe an invalid actuation signal affecting more than one system. On September 19, 2011, at 1000 hours Central Daylight Time (CDT), during the performance of a maintenance activity on the Reactor/Refueling Zone Ventilation Radiation Monitor BFN-3-RM-090-0141/143, Browns Ferry Unit 3 received a Primary Containment Isolation System (PCIS) Group 6 isolation. This resulted in isolation of the reactor and refuel zone ventilation systems, initiation of the Standby Gas Treatment System (Trains A, B and C), and the initiation of the Control Room Emergency Ventilation System (Trains A and B). All plant systems responded as designed. There are two divisions of Reactor/Refueling Zone Ventilation Radiation Monitors: BFN-3-RM-090-0140/142 and BFN-3-RM-090-0141/143. A downscale or inoperable signal in both divisions will initiate the PCIS Group 6 isolation. Prior to the performance of the maintenance activity, BFN-3-RM-090-0140/142 was functional. However, during a field walkdown after the PCIS Group 6 isolation, relay BFN-3-RLY-064-16AK62A for BFN-3-RM-090-0140/142 was discovered to be chattering. A chattering relay could cause momentary loss of continuity between the contacts which would effectively generate a spurious isolation signal from that division. Thus, when 3-RM-090-0141/143 was made inoperable by the surveillance, the PCIS Group 6 logic was made-up. The PCIS Group 6 isolation was reset at 1008 CDT. This event was entered in the Corrective Action Program as Problem Evaluation Report (PER) 434799. There were no safety consequences or impact on the health and safety of the public as a result of these events. The NRC Senior Resident Inspector was notified. |