| | Site | Start date | Title | Description |
|---|
| ENS 57199 | Monticello | 28 June 2024 06:10:00 | Both Divisions of Lpci Inoperable | The following information was provided by the licensee via email:
This condition is being reported in accordance with 10 CFR50.72(b)(3)(v) as a condition that could have prevented fulfillment of a safety function. On 6/27/2024 at 2158 CDT, (technical specification) TS 3.5.1 condition 'D' (both divisions of (low pressure coolant injection) LPCI inoperable) was entered for surveillance testing. On 6/28/2024 at 0110 CDT, MO-2012 (residual heat removal) RHR Division 1 LPCI injection outboard valve was attempted to be cycled. It was discovered to be inoperable resulting in an inability to exit TS 3.5.1 'D'. Initial review of this condition for immediate reportability under 50.72(b)(3)(v) event or a condition that could have prevented fulfillment of a safety function, concluded the condition was not reportable based on the operability of other emergency core cooling systems (ECCS). Specifically, core spray and high pressure coolant injection were both operable to perform the function of emergency core cooling. Subsequent reviews determined that the reportability decision under 50.72(b)(3)(v) as an event or condition that could have prevented fulfillment of a safety function should be based on the safety function at the LPCI system level, rather than at the ECCS system level. The decision to report the inoperability of LPCI under 50.72(b)(3)(v) was made at 1030 CDT on 6/28/2024. The NRC Resident Inspector has been notified. |
| ENS 57120 | FitzPatrick | 9 May 2024 20:29:00 | High Pressure Coolant Injection Inoperable | The following information was provided by the licensee via phone and email:
At 1629 EDT on 05/09/2024, the high pressure coolant injection (HPCI) system was declared inoperable due to a pinhole through-wall leak identified on the seal drain line for 23HOV-1 (HPCI trip throttle valve) downstream of the restricting orifice 23RO-137A. The location of the defect is in the class 2 safety related piping. HPCI 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 Senior Resident Inspector has been notified.
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
This pinhole leak was discovered during normal operator rounds. Although HPCI is declared inoperable and in a 14-day limited condition of operation, the system function remains available. In addition, all other ECCS systems are currently operable. Compensatory measures (walkdowns) have been implemented to ensure the leak rate does not significantly increase.
- * * RETRACTION ON 06/20/2024 AT 1423 EDT FROM CAMERON KELLER TO ROBERT THOMPSON * * *
FitzPatrick performed an additional technical evaluation of the steam leak identified on May 9, 2024. The evaluation concluded that the HPCI system would have remained operable and performed its specified safety function with a postulated complete failure of this pipe, considering its size, location, and impact of the leak. Additionally, all components in the vicinity would have retained their required safety functions. Based on this conclusion, EN 57120 is being retracted.
The NRC Senior Resident Inspector has been notified.
Notified R1DO (Elkhiamy). |
| ENS 57090 | Browns Ferry | 25 April 2024 03:15:00 | Automatic Reactor Scram with Eccs Actuation | The following information was provided by the licensee via email:
On 4/24/2024 at 2215 CDT, Browns Ferry Unit 1 experienced an automatic reactor scram. The cause of the scram is currently under investigation. The main steam isolation valves (MSIVs) remain open with the main turbine bypass valves controlling reactor pressure. The reactor feedwater pumps are in service to control reactor water level.
Primary containment isolation systems (PCIS) Groups 2, 3, 6, and 8 isolation signals were received. Upon receipt of these signals, all components actuated as required. Following the reactor scram, due to reactor water level reaching minus 45 inches, both high pressure coolant injection (HPCI) and reactor core isolation cooling (RCIC) initiation signals were received, and both initiated as designed. All safety systems operated as expected.
This event requires a 4-hour report per 10 CFR 50.72(b)(2)(iv)(A), `Any event that results or should have resulted in emergency core cooling system (ECCS) discharge into the reactor coolant system as a result of a valid signal except when the actuation results from and is part of a pre-planned sequence during testing or reactor operation.
This event requires a 4-hour report per 10 CFR 50.72(b)(2)(iv)(B), `Any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical except when the actuation results from and is part of a pre-planned sequence during testing or reactor operation.
This event requires an 8-hour report per 10 CFR 50.72(b)(3)(iv)(A), `Any event or condition that results in valid actuation of any of the systems listed in paragraph (b)(3)(iv)(B): 1) Reactor protection system (RPS) including: reactor scram or reactor trip. 2) General containment isolation signals affecting containment isolation valves in more than one system or multiple main steam isolation valves (MSIVs). 4) ECCS for boiling water reactors (BWRs) - high-pressure coolant injection (HPCI). 5) BWR reactor core isolation cooling system (RCIC).
All safety systems operated as expected. At no time was public health and safety at risk. The NRC resident inspector has been notified.
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
Units 2 and 3 were not affected. |
| ENS 57036 | Browns Ferry | 19 March 2024 15:30:00 | 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. |
| ENS 57041 | Cooper | 13 March 2024 10:48:00 | High Pressure Coolant Injection (HPCI) Inoperable | The following information was provided by the licensee via email and phone:
At 0548 CDT on March 13, 2024, during a planned (high pressure coolant injection) HPCI maintenance window, a condition was identified not associated with the planned maintenance which caused HPCI to be inoperable. Specifically, the HPCI auxiliary oil pump start stop pressure switch could not be adjusted into calibration. Further investigation found that the pressure switch was not mounted as designed.
Since HPCI is a single train system, this is a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). The condition was corrected prior to HPCI being declared operable on March 15, 2024.
The reason for the delay in the event notification beyond 8 hours from the event time was due to not recognizing the need to report the condition while in a planned HPCI maintenance window.
The NRC Senior Resident Inspector has been notified. |
| ENS 56989 | Cooper | 22 February 2024 17:03:00 | Accident Mitigation - High Pressure Coolant Iinjection Declared Inoperable | The following information was provided by the licensee via email:
At 1103 CST on February 22, 2024, a potential through-wall steam leak was identified on the high pressure coolant injection (HPCI) steam supply 1-inch drain line. As a result, HPCI was declared inoperable. Since HPCI is a single-train system, this is a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). Reactor core isolation cooling (RCIC) and low pressure emergency core cooling systems (ECCS) remain operable.
Additional investigation is in progress.
There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ML24032A476 | Browns Ferry | 1 February 2024 | Final Report of a Part 21 Evaluation Associated with Starter Contactors for the BFN Unit 1 High Pressure Coolant Injection Suppression Pool Inboard Suction Valve | |
| IR 05000220/2023004 | Nine Mile Point | 1 February 2024 | Integrated Inspection Report 05000220/2023004 and 05000410/2023004 | |
| IR 05000321/2023004 | Hatch | 31 January 2024 | Integrated Inspection Report 05000321/2023004 and 05000366/2023004 | |
| ENS 56936 | Peach Bottom | 29 January 2024 17:02:00 | Automatic Reactor Scram | The following information was provided by the licensee via email:
At approximately 1202 EST on 01/29/24, unit 2 experienced a reactor scram caused by a main turbine trip. Investigation is still ongoing.
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
All control rods were fully inserted. The licensee indicated that the turbine trip may have been caused by a power load imbalance, however the cause of the incident is under investigation. The scram was not complex.
Decay heat is currently being removed thru bypass valves dumping to the main condenser. Initially unit 2 lost the use of the bypass valves due to lack of condenser vacuum. Unit 2 used the high pressure coolant injection (HPCI) system in the condenser storage tank (CST) to CST mode to remove decay heat. Residual heat removal was used to keep the torus cool. Condenser vacuum was regained and unit 2 is back to removing decay heat with the turbine bypass valves.
There was no impact to unit 3.
The licensee confirmed there was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
- * *UPDATE ON 01/29/24 AT 1935 EST FROM PAUL BOKUS TO NATALIE STARFISH* * *
The following information was provided by the licensee via email:
Licensee adds 8-hour non-emergency 10 CFR 50.72(b)(3)(iv)(A) specified system actuation report to original 4-hour non-emergency 10 CFR 50.72(b)(2)(iv)(B) RPS Actuation report.
At approximately 1202 EST on 01/29/24, unit 2 experienced a reactor scram by a main turbine trip. All control rods inserted. Reactor core isolation cooling system (RCIC) was manually initiated for level control. HPCI was manually initiated for pressure control. Primary containment isolation system (PCIS) Group II and III isolations occurred (specified system actuation). Investigation is ongoing.
The NRC Resident Inspector has been notified. |