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| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 56644 | 30 July 2023 16:19:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Control Room Envelope Inoperable | The following information was provided by the licensee via email: On July 30, 2023 at 1119 CDT, Waterford Steam Electric Station Unit 3 declared the control room envelope inoperable in accordance with technical specification (TS) 3.7.6.1 due to the control room envelope doors failing a door seal smoke test creating a breach in the control room envelope. Operations entered TS 3.7.6.1 Action b. Mitigating actions were implemented and tested satisfactorily by 1215 CDT. There was no impact on the health and safety of the public or plant personnel. This event is reportable pursuant to 10 CFR 50.72(b)(3)(v)(D), as an event or condition that could have prevented fulfillment of a safety function of structures or systems that are needed to mitigate the consequences of an accident, due to the control room envelope being inoperable. The NRC Resident Inspector has been notified.
The original operability determination of inoperable was made based on a conservative evaluation that with presence of smoke in-leakage through Door 261 and 262, the CRE boundary could not perform its safety function. A more detailed engineering evaluation was subsequently performed. No maintenance or intrusive testing was performed on the doors after initial test failure. As documented in version 2 operability determination for condition report WF3-2023-14604, the CRE boundary remained intact for the condition identified and was able to fulfill its safety function. The licensee has notified the NRC Resident Inspector. Notified R4DO (Warnick). | Control Room Envelope | |
| ENS 55436 | 29 August 2021 23:04:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Safety System Actuation | At 1804 CDT on 8/29/2021, Waterford 3 Steam Electric Station (WF3) experienced a Loss of Off Site Power event due to Hurricane Ida (See EN #55435). This event caused an automatic actuation of Emergency Diesel Generators Trains A and B. Both Emergency Diesel Generators started as designed and both are currently operating normally supplying power to their respective Class 1E Safety Busses. This automatic actuation is reportable in accordance with 10 CFR 50.72(b)(3)(iv)(A). Prior to the loss of offsite power, WF3 was in progress of performing a plant cooldown in accordance with procedural guidance. As part of this cooldown and after entering Mode 4, all Safety Injection Tanks were isolated. As a result of losing offsite power, Reactor Coolant System Temperature increased above 350F which is above the temperature requirements for Mode 4. Safety Injection Tanks are required to be unisolated and OPERABLE in Mode 3. Therefore, with no Safety Injection Tanks OPERABLE, this constituted an event or condition that could have prevented the fulfillment of a safety function and the unit entered Technical Specification 3.0.3. The unit was in Technical Specification 3.0.3 for approximately 43 minutes from 1805 CDT until 1848 CDT when Mode 4 conditions were re-established. This event or condition that could have prevented the fulfillment of a Safety Function is reportable in accordance with 10 CFR 50.72(b)(3)(v)(D). While continuing to perform the Reactor Coolant System Cooldown and prior to placing Shutdown Cooling Train in service, it became necessary to start one train of Emergency Feedwater. Emergency Feedwater Train A was manually started at 1847 CDT to feed the Steam Generators and was secured at 1947 CDT. Emergency Feedwater Train A started and operated normally during this period. This manual actuation is reportable in accordance with 10 CFR 50.72(b)(3)(iv)(A). The licensee notified the NRC Resident Inspector.
The purpose of this notification is to revise Event Notification Report (EN) 55436 to include a partial retraction. On August 29, 2021, Waterford Steam Electric Station, Unit 3 (WF3) experienced a loss of offsite power (LOOP) event due to Hurricane Ida. Prior to the LOOP, WF3 had shutdown to Mode 3 (Hot Standby) in anticipation of the LOOP and was performing a plant cooldown in accordance with procedural guidance. When Mode 4 (Hot Shutdown) was achieved, all Safety Injection Tanks (SITs) were isolated as part of the plant cooldown. After the LOOP, Reactor Coolant System (RCS) temperature increased and the Core Exit Thermocouples (CETs) indicated that RCS temperature had exceeded 350 degrees F. Based on the CETs, this was above the temperature requirements for Mode 4 and, as such, WF3 declared entry into Mode 3. The SITs are required to be unisolated and Operable in Mode 3. Since no SITs were Operable at that time, it was determined that this constituted an event or condition that could have prevented the fulfillment of a safety function and included this as part of the EN 55436 report in accordance with 10 CFR 50.72(b)(3)(v)(D). An engineering evaluation has subsequently been performed to validate whether the RCS temperature excursion following the LOOP actually reached 350 degrees F. As defined in WF3 Technical Specification (TS) Table 1.2, Operational Mode temperatures are a function of RCS average temperature (Tavg), not just the indicated temperature of the CETs. Based on the calculated Tavg using validated temperatures, it was concluded that 350 degrees F was not reached. Thus, WF3 remained in Mode 4 following the LOOP and there was no event or condition that could have prevented the fulfillment of a safety function that was reportable pursuant to 10 CFR 50.72(b)(3)(v)(D). The remainder of EN 55436 remains correct and unchanged. The licensee notified the NRC Resident Inspector. Notified R4DO (Pick) | Steam Generator Reactor Coolant System Feedwater Emergency Diesel Generator Shutdown Cooling | |
| ENS 54191 | 31 July 2019 17:06:00 | 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)(2)(i), Tech Spec Required Shutdown | Technical Specification Required Shutdown Due to Inoperable Boron Injection Flow Paths and Charging Pumps | On July 31, 2019, at 1206 CDT, Waterford 3 commenced initiation of a plant shutdown as required by Technical Specification (TS) Limiting Condition for Operation (LCO) 3.0.3. Prior to this, on July 31, 2019, at 1108 CDT, the boron injection flow paths were declared inoperable in accordance with LCO 3.1.2.2, 'Flow Paths - Operating,' and the charging pumps were declared inoperable in accordance with LCO 3.1.2.4, 'Charging Pumps-Operating.' This was due to visual examination identifying that propagation had progressed on a previously identified flaw on piping upstream of the header supplying the charging pumps. TS LCO 3.0.3 was entered due to the action statements of LCOs 3.1.2.2 and 3.1.2.4 not being met. LCO 3.0.3 requires that action shall be initiated within one hour to place the unit in a mode in which the specification does not apply by placing it in hot standby within the next 6 hours and cold shutdown within the next 30 hours. At 1206 CDT, Waterford 3 commenced direct boration to the reactor coolant system. This condition meets the reporting criteria of 10 CFR 50.72(b)(2)(i) due to the initiation of plant shutdown required by Technical Specifications and 10 CFR 50.72(b)(3)(v)(A) and (D) due to an event or condition that could have prevented fulfillment of a safety function of structures or systems that are needed to (A) shutdown the reactor and maintain it in a safe shutdown condition and (D) mitigate the consequences of an accident. | Reactor Coolant System | |
| ENS 54131 | 25 June 2019 09:28:00 | 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 | Control Room Envelope Inoperable Due to Broad Range Gas Monitors Being Inoperable | On June 25, 2019, at 0428 CDT, the Waterford 3 shift operating crew declared the control room envelope inoperable in accordance with Technical Specification (TS) 3.7.6.1 due to both Broad Range Gas Monitors being inoperable. Operations entered TS 3.7.6.1 action b, which requires that with one or more control room emergency air filtration trains inoperable due to inoperable control room envelope boundary in Modes 1, 2, 3, or 4, then: 1. Immediately initiate action to implement mitigating actions; 2. Within 24 hours, verify mitigating actions ensure control room envelope occupant exposures to radiological, chemical, and smoke hazards will not exceed limits; and 3. Within 90 days, restore the control room envelope boundary to operable status. Action b.1 was completed by placing the control room in isolate mode at time 0441 CDT. This event is reportable pursuant to 10 CFR 50.72(b)(3)(v)(A) and 10 CFR 50.72(b)(3)(v)(D), event or condition that could have prevented fulfillment of a safety function of structures or systems that are needed to (A) shutdown the reactor and maintain it in shutdown condition and (D) mitigate the consequences of an accident, due to the control room envelope being inoperable. The NRC Senior Resident Inspector has been notified. | Control Room Envelope | |
| ENS 53991 | 11 April 2019 07:00:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Control Room Envelope Inoperable Due to Door Handle Detaching | On April 11, 2019, at 0200 CDT the shift operating crew declared the control room envelope inoperable in accordance with Technical Specification (TS) 3.7.6.1 due to the door handle for Door 86 (H&V Airlock Access Door) being detached. Operations entered TS 3.7.6.1 action b, which requires that with one or more control room emergency air filtration trains inoperable due to inoperable control room envelope boundary in MODES 1, 2, 3, or 4, then: 1. Immediately initiate action to implement mitigating actions; 2. Within 24 hours, verify mitigating actions ensure control room envelope occupant exposures to radiological, chemical, and smoke hazards will not exceed limits; and 3. Within 90 days, restore the control room envelope boundary to OPERABLE status. Action b.1 was completed by sealing the hole in Door 86 at 0232 CDT. This event is reportable pursuant to 10 CFR 50.72(b)(3)(v)(D), 'event or condition that could have prevented fulfilment of a safety function of structures or systems that are needed to (D) mitigate the consequences of an accident,' due to the control room envelope being inoperable. The licensee notified the NRC Resident.
This is a Non-Emergency Notification from Waterford 3. This is a retraction of EN 53991. This event was evaluated in accordance with the corrective action process. The original operability determination of inoperable was made based on a conservative evaluation that with the door handle for Door 86 (Heating and Ventilation Airlock Access Door) being detached, the control room envelope boundary could not perform its safety function. A more detailed engineering evaluation was subsequently performed. This shows that the condition of the door handle being detached is bounded by the most recently performed non-pressurized radiological tracer gas test, as the control room envelope differential pressure was maintained more positive with the detached door handle as compared to that observed during the test. Additionally, the control room envelope differential pressure trends showed no discernable change between the two conditions of the door handle detached or with the opening taped over (resulting in an air tight seal). This information supports the conclusion that with the door handle for Door 86 being detached, the control room envelope boundary remained operable and did not constitute a condition that could have prevented fulfillment of a safety function of structures or systems that are needed to mitigate the consequences of an accident; therefore, this event is not reportable per 10 CFR 50.72(b)(3)(v)(D). The licensee notified the NRC Resident Inspector. Notified R4DO (Proulx). | Control Room Envelope | |
| ENS 53796 | 19 December 2018 06:00:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Control Room Envelope Inoperable | On December 19, 2018, at 2322 CST, the shift operating crew declared the control room envelope inoperable in accordance with Technical Specification (TS) 3.7.6.1 due to valve HVC-102 exceeding its maximum allowed closed stroke time of 2.0 seconds during performing of surveillance procedure OP-903-119. Actual closed stroke time was 2.1 seconds. Valve HVC-102 is part of the control room envelope. TS 3.7.6.1 requires that two control room emergency air filtration trains shall be OPERABLE. Operations entered TS 3.7.6.1 action b, which requires that with one or more control room emergency air filtration trains inoperable due to inoperable control room envelope boundary in MODES 1, 2, 3, or 4, then: 1. immediately initiate action to implement mitigating actions; 2. within 24 hours, verify mitigating actions ensure control room envelope occupant exposures to radiological, chemical, and smoke hazards will not exceed limits; and 3. within 90 days, restore the control room envelope boundary to OPERABLE status. Actions b.1 and b.2 were completed by placing the control room ventilation system in isolate mode at 2355. This event is reportable pursuant to 10 CFR 50.72(b)(3)(v)(D), 'event or condition that could have prevented fulfillment of a safety function of structures or systems that are needed to (D) mitigate the consequences of an accident,' due to the control room envelope being inoperable. The NRC Resident Inspector has been notified. | Control Room Envelope | |
| ENS 52600 | 8 March 2017 22:27:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Both Trains of Low Pressure Safety Injection Inoperable Due to Maintenance Error | This is a non-emergency notification from Waterford 3. On March 8, 2017 at 1627 (CST) Technical Specification (TS) 3.5.2 action 'c' was entered due to both trains of Low Pressure Safety Injection (LPSI) being inoperable. This TS action requires one train of LPSI be restored within 1 hour or be in at least Hot Standby within the next 6 hours. It was identified that LPSI train B was inoperable due to SI-135B, Reactor Coolant Loop 1 Shutdown Cooling Warmup Valve, being found open. At the time of discovery, LPSI train A was inoperable for pre planned maintenance, but available and awaiting operability retest. The station was in compliance with TS 3.5.2 action 'a'. Maintenance workers were scheduled to work Sl-135A Reactor Coolant Loop 2 Shutdown Cooling Warmup Valve, and inadvertently began work on Sl-135B and manually opened the valve which resulted in the LPSI Train B being inoperable. Once identified by Operations Control Room staff, the valve (SI-135B) was placed in the closed position and stroke tested to ensure operability. TS 3.5.2 action 'c' was exited at time 1705. The station remained in compliance with TS 3.5.2 action 'a'. The licensee notified the NRC Resident Inspector. | Shutdown Cooling | |
| ENS 52321 | 27 October 2016 05:21:00 | 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 | Loss of Charging and Letdown Systems from the Reactor Coolant System | At 0021 (CDT) on 10/27/16, Waterford 3 (WF3) experienced a loss of the charging and letdown systems from the Reactor Coolant System (RCS). Technical Specification (TS) 3.0.3 was entered due to the loss of all three charging pumps. Charging Pump AB was restored and aligned to replace Charging Pump A and WF3 exited TS 3.0.3 at 0055 on 10/27/16. The cause of the loss of charging pumps was due to Refueling Water Storage Pool to Charging Pumps Suction Isolation, CVC-507, not opening as expected following a loss of Static Uninterruptible Power Supply (SUPS) 014AB during electrical troubleshooting. The cause of CVC-507 not opening is being investigated. Power was restored to SUPS 014AB at 0022. WF3 is currently stable in Mode 3 with decay heat being removed by the Steam Bypass Control System. Pressurizer Level was maintained throughout the event. WF3 was previously shut down for reasons unrelated to this event. The NRC Resident Inspector has been notified. Valve CVC-183 closed when the power supply was lost. CVC-183 is the Volume Control Tank outlet isolation valve. Waterford 3 will remain in mode 3 until the issue has been corrected.
This is a retraction of EN 52321 which was reported as an 8 hour Non-Emergency on October 27th at 0826 EST. At 0021 (EST) on 10/27/16, Waterford 3 (WF3) experienced a loss of the charging and letdown systems due to an electrical transient on a Static Uninterruptable Power Supply that was being worked under a maintenance work order. The cause of the loss of charging pumps was due to Refueling Water Storage Pool to Charging Pumps Suction Isolation, CVC-507, not opening as expected following a loss of Static Uninterruptible Power Supply (SUPS) 014AB. Both operating charging pumps automatically secured due to low suction pressure trips as designed. Post event investigation determined that a relay that had failed affected only the normal suction path isolation valves to the charging pumps and did not impact the safety related flow path that is required during a Safety Injection Actuation Signal (SIAS). Had an SIAS occurred during the period when no active suction path was aligned, the low pressure trip would have been blocked and the pumps selected to start on an SIAS would have auto started. The SIAS would have aligned the Boric Acid Make-up system for Emergency Boration. This would have resulted in the Charging Pumps being aligned to take suction from the Boric Acid Make-up pumps and/or Boric Acid Gravity Feed valves. A function of the charging systems is to inject concentrated boric acid into RCS upon an SIAS. As discussed in FSAR Section 6.3.3.3.1, the injection flow from the charging pumps is not credited in the small break LOCA analysis. Charging is however credited for natural circulation cooldown without letdown in order to meet the safe shutdown requirements of NRC Branch Technical Position (RSB) 5-4. This analysis assumes that the charging source is initially Boric Acid Makeup Tanks followed by Refueling Water Storage Pool. Both sources were available. The charging system was fully capable of performing its safety function following the relay failure. The charging pumps remained capable of starting on an SIAS and the flow path from the Boric Acid Management system remained operable. In addition the flow path from the RWSP was not affected since the outlet isolation valve could be manually opened. The NRC Resident Inspector has been notified. Notified the R4DO (Taylor). | Reactor Coolant System Steam Bypass Control System | |
| ENS 52179 | 12 August 2016 22:04:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Loss of Both Loops of Essential Services Chilled Water | This is a non-emergency notification from Waterford 3. On August 12, 2016, at 1704 CDT, the shift operating crew entered Technical Specification (TS) 3.0.3 due to both trains of Essential Services Chilled Water being inoperable. Essential Services Chilled Water Loop A had previously been declared inoperable for maintenance on August 11, 2016. On August 12, 2016, at 1704, the shift operating crew noted that Loop B Essential Services Chilled Water outlet temperature exceeded the allowed TS limit of 42 degrees Fahrenheit. Essential Chiller AB was subsequently aligned to Loop B and TS 3.0.3 was exited on August 12, 2016 at 1802 when outlet temperature was verified less than or equal to 42 degrees Fahrenheit. On August 15, 2016, subsequent review of this event determined that this event was reportable under 10 CFR 50.72(b)(3)(v)(D), 'event or condition that could have prevented fulfillment of a safety function of structures or systems that are needed to (D) mitigate the consequences of an accident' due to both Essential Services Chilled Water Loops being inoperable. The NRC Resident Inspector has been notified. | ||
| ENS 51348 | 26 August 2015 12:40:00 | 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 | Both Emergency Diesel Generators Declared Inoperable | This is a non-emergency notification from Waterford 3. On August 26, 2015, at 0111 CDT, Emergency Diesel Generator (EDG) 'A' was declared inoperable following a trip of EDG 'A' on Generator Differential. Technical Specification (TS) 3.8.1.1 actions b. and d. were entered. EDG 'A' was being routinely run in accordance with OP-903-115, 'Train A Integrated Emergency Diesel Generator/Engineering Safety Features Test', Section 7.4, '24 hr EDG A Run with Subsequent Diesel Start' to satisfy Technical Specification Surveillance Requirement 4.8.1.1.2 6. EDG 'B' was subsequently started per TS 3.8.1.1 action b. (1). At 0740 CDT, EDG 'B' was declared inoperable and TS 3.8.1.1 f. was entered due to the exhaust fan not starting when the diesel engine was started. Troubleshooting determined that the EDG B exhaust fan did not start due to HVR-501B (EG B ROOM OUTSIDE AIR INTAKE DAMPER) not opening. Action was taken to isolate air and fail HVR-501B to its open safety position. At 1001 CDT, EDG 'B' was declared operable and TS 3.8.1.1.f. was exited following verification of proper operation of the EDG 'B' exhaust fan. Waterford 3 is currently in TS 3.8.1.1 actions b. and d. Actions to verify a temporary EDG is available and restore EDG 'A' to operable status are in progress. This event is reportable pursuant to 10 CFR 50.72(b)(3)(v) (A) and 10 CFR 50.72 (b)(3)(v) (D), 'event or condition that could have prevented fulfillment of a safety function of structures or systems that are needed to (A) shut down the reactor and maintain it in a safe shutdown condition' and (D) 'mitigate the consequences of an accident due to both emergency diesel generators being inoperable.' The NRC Resident Inspector has been notified.
The following is a correction to a non-emergency event notification from Waterford 3 originally made on 8/26/2015: On August 26, 2015, at 0111 CDT, Emergency Diesel Generator (EDG) 'A' was declared inoperable following a trip of EDG 'A' on Generator Differential. Technical Specification (TS) 3.8.1.1 actions b and d were entered. EDG 'A' was being routinely run in accordance with OP-903-115, 'Train A Integrated Emergency Diesel Generator/Engineering Safety Features Test,' Section 7.4, '24 hr EDG A Run with Subsequent Diesel Start' to satisfy Technical Specification Surveillance Requirement 4.8.1.1.2(e)6. EDG 'B' was subsequently started per TS 3.8.1.1 action b.(1). At 0740 CDT, EDG 'B' was declared inoperable and TS 3.8.1.1 f was entered due to the room exhaust fan not starting when the diesel engine was started. Troubleshooting determined that the EDG B room exhaust fan did not start due to HVR-501B (EDG B ROOM OUTSIDE AIR INTAKE DAMPER) not opening. Action was taken to isolate air and fail HVR-501B to its open safety position. At 1001 CDT, EDG 'B' was declared operable and TS 3.8.1.1.f was exited following verification of proper operation of the EDG 'B' room exhaust fan. Waterford 3 is currently in TS 3.8.1.1 actions b and d. Actions to verify a temporary EDG is available and restore EDG 'A' to operable status are in progress. This event is reportable pursuant to 10 CFR 50.72(b)(3)(v)(A) and 10 CFR 50.72(b)(3)(v)(D), Event or Condition that Could Have Prevented Fulfillment of a Safety Function of structures or systems that are needed to (A) shut down the reactor and maintain it in a safe shutdown condition and (D) mitigate the consequences of an accident due to both emergency diesel generators being inoperable. The NRC Resident Inspector has been notified. Notified R4DO (Warnick) | Emergency Diesel Generator | |
| ENS 50378 | 18 August 2014 13:53:00 | 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 | Ultimate Heat Sink System Inoperable | Conditions were met that require immediate NRC notification per 10 CFR 50.72(b)(3)(v)(B) and 10 CFR 50.72(b)(3)(v)(D) due to both trains of the Ultimate Heat Sink (UHS) system being inoperable for approximately 83 minutes. This condition resulted from a planned system outage of train B Component Cooling Water (CCW), as a subsystem of the Train B UHS, and an unexpected trip of a Train A Auxiliary Component Cooling Water (ACCW) Wet Cooling Tower (WCT) fan, which is also a subsystem of the Train A UHS. CCW Train B was declared inoperable at 0820 CDT and removed from service for a planned relay replacement, resulting in entry of 72 hour shutdown Technical Specification (TS) LCO 3.7.3, and associated cascading TS on Train B, including TS LCO 3.7.4 Action a. Subsequently, at approximately 0853 (CDT), the 6A ACCW WCT fan tripped, rendering the redundant Train A UHS inoperable, causing entry into 1 hour TS LCO 3.7.4 Action b, which states, 'With both UHS trains inoperable, restore at least one UHS train to OPERABLE status within 1 hour or be in at least HOT STANDBY within the next 6 hours and COLD SHUTDOWN within the following 30 hours.' At approximately 0948 CDT the WCT Fan 6A electric motor thermal overload relays were reset, the fan restarted, and operated properly. At 1016 CDT, CCW train B had been restored from the planned maintenance and was declared operable, exiting TS LCO 3.7.3 and associated cascading TSs on Train B. Although a plant shutdown was not commenced following expiration of the one hour specified in TS LCO 3.7.4 ACTION b, Operations was preparing for a power reduction and TS required plant shutdown. During this reported condition, an outside air intake valve of the Control Room Emergency Filtration system was inoperable for planned maintenance, for which TS 3.7.6.1 mitigating actions were in place. This valve was restored to Operable at 1210 CDT. Other safety systems remained available. The plant remained stable at 100% during this time. The NRC Resident Inspector was notified. | Control Room Emergency Filtration System |