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| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 56957 | 9 February 2024 18:22:00 | 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | Unanalyzed Condition - Inadequate Fuses for Fuel Pool Cooling | The following information was provided by the licensee via email: On 2/9/24 at 1322 EST, it was determined that the unit was in an unanalyzed condition. A review of DC feeder circuit protection schemes identified a circuit for the fuel pool cooling system is uncoordinated due to inadequate fuse sizing. This results in a concern that postulated fire damage in one area could cause a short circuit without adequate protection, leading to the unavailability of equipment credited for in 10 CFR 50 Appendix R, Fire Safe Shutdown. This condition is not bounded by existing design and licensing documents; however, it poses no impact to the health and safety of the public or plant personnel. Therefore, this event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B). The postulated event affects the following fire zones: fire areas 6S and 6N (within the Unit 2 reactor building). Compensatory actions for affected fire areas have been implemented. An extent of condition review is being performed. 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: Fire watches have been established in the affected areas. These will be maintained until the protection scheme is revised.
The following updated information was provided by the licensee via email and phone call: On 03/08/24 at 1418, extent of condition reviews identified circuit(s) in the Units 2 and 3 Reactor Protection Systems (RPS) which are also uncoordinated due to improper fuse sizing. These circuits are not bounded by existing design and licensing documents for 10 CFR 50 Appendix R Fire Safe Shutdown and, therefore, this event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B). This event poses no impact to the health and safety of the public or plant personnel. The postulated event affects the following fire areas: 32, 33, 38 and 39 (Units 2 and 3 Switchgear Rooms). In accordance with procedural requirements, compensatory actions for the affected fire areas have been implemented and will remain until the condition is resolved. The NRC Senior Resident Inspector has been notified. Notified R1DO (Arner)
On March 13, 2024, at 1350 EDT, extent of condition reviews identified a circuit in the Unit 2 reactor protection system (RPS) which is also uncoordinated due to improper fuse sizing. This circuit is not bounded by existing design and licensing documents for 10 CFR 50, Appendix R, Fire Safe Shutdown, therefore, this event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B). This event poses no impact to the health and safety of the public or plant personnel. The postulated event affects fire area 57 (Switchgear Corridor, common to Units 2 and 3). In accordance with procedural requirements, compensatory actions for the affected fire areas have been implemented and will remain until the condition is resolved. Additionally, it was previously reported that fire area 6N contained a circuit which was not bounded by the Fire Safe Shutdown analysis; however, after further review it has been determined that compliance is maintained in this fire area and is therefore retracted from the scope of this report. The NRC Senior Resident Inspector has been notified. Notified R1DO (Jackson)
The following information was provided by the licensee via email: On 03/21/24 at 1211, extent of condition reviews identified an annunciator circuit for the Unit 3 emergency service water (ESW) and high pressure service water (HPSW) pump structure heating and ventilation panel that is also uncoordinated due to improper fuse sizing. This circuit is not bounded by existing design and licensing documents for 10 CFR 50 Appendix R Fire Safe Shutdown and, therefore, this event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B). This event poses no impact to the health and safety of the public or plant personnel. The postulated event affects fire area 47 (Unit 3 pump structure for `B' ESW and `3A'-`3D' HPSW pumps) and the yard fire area (Manhole 026D). In order to restore immediate compliance, the cable has been de-energized to eliminate the possibility of the event of concern. This circuit will remain de-energized or other measures will be implemented until the condition is permanently resolved. The NRC Senior Resident Inspector has been notified. Notified R1DO (Ford) | Service water Reactor Protection System | |
| ENS 53265 | 15 March 2018 19:24:00 | 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | Failure to Meet Appendix R Requirements | At 1524 (EDT) on Thursday, March 15, 2018, Operations was notified of a failure to meet Appendix R requirements for Peach Bottom Atomic Power Station (PBAPS) Unit 2 and Unit 3. Valves associated with the feedwater system for both units were not properly considered as Hi-Lo Pressure interface valves as required by the Appendix R program. This results in the susceptibility to a hot short condition that could open valves, diverting flow from the reactor, damage piping and prevent injection. U3 (Unit 3) Fire Safe Shutdown Credited Reactor Core Isolation Cooling (RCIC) System is affected. U2 (Unit 2) is affected by a potential leak path through the Reactor Water Cleanup system. This event is being reported as an occurrence of an event or condition that results in the nuclear power plant being in an unanalyzed condition that significantly degrades plant safety under 10 CFR 50.72(b)(3)(ii). The Station (PBAPS) is performing hourly fire watches for the impacted areas and is also evaluating this condition for corrective action. The licensee notified the NRC Resident Inspector. | Feedwater Reactor Core Isolation Cooling Reactor Water Cleanup | |
| ENS 52478 | 9 January 2017 20:30:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | Emergency Diesel Generators Non-Conforming with Licensing Basis for Tornado Generated Missiles | On January 9, 2017, during evaluation of protection for Technical Specification (TS) equipment from the damaging effects of tornado generated missiles, Peach Bottom Atomic Power Station identified a non-conforming condition in the plant design such that specific TS equipment is considered to not be adequately protected from tornado generated missiles. A tornado could generate multiple missiles that could strike one or more of the four emergency diesel generator (EDG) exhaust stacks. This could result in crimping of the stack, which could affect the ability of the EDG to perform its design function if such a tornado would occur. This condition is reportable per 10 CFR 50.72(b)(3)(ii)(B) for any event or condition that results in the nuclear power plant being in an unanalyzed condition that significantly degrades plant safety, and per 10 CFR 50.72(b)(3)(v)(D) for 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 condition is being addressed in accordance with NRC enforcement guidance provided in EGM 15-002 and DSS-ISG-2016-01. Compensatory measures have been implemented in accordance with these documents. The NRC Resident Inspector has been informed of this notification. | Emergency Diesel Generator | |
| ENS 50128 | 21 May 2014 15:00:00 | 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | Unanalyzed Condition Involving Fire Safe Shutdown Capability | This notification is to report a condition involving degraded control power wiring that resulted in an adverse impact on the ability to perform Fire Safe Shutdown for a postulated fire in the Main Control Room / Cable Spreading Room (MCR/CSR) complex. Therefore, this notification is being made pursuant to 10CFR 50.72(b)(3)(ii)(B). At approximately 1100 hours (EDT), based on inspections being performed as part of an extent-of-condition review, Engineering personnel concluded that a degradation existed involving transfer / isolation switches that potentially impacted the ability to mitigate an Appendix R fire postulated to occur in the MCR/CSR complex. During scheduled maintenance outage windows on March 6, 2014 and May 5, 2014, broken wires were identified and repaired while the associated systems were out of service. Based on completion of the extent of condition walkdowns today, an additional location was identified, raising the potential that this condition existed for a longer period of time. The wiring degradation is limited to the capability of using Shutdown Method 'D' as described in the Peach Bottom Atomic Power Station Fire Protection Program. Shutdown Methods 'A', 'B' and 'C' used for other postulated fire areas were not affected by this condition. The postulated fire would have had to cause the normal control power fuses to fail for the issue to impact the safe shutdown function. Compensatory measures have been established until the condition is corrected. The NRC Resident Inspector has been informed of this notification. In the event of fire resulting in a loss of control power, compensatory measures will allow restoration of control power by replacing blown fuses. The compensatory measures are detailed in a temporary change to the MCR/CSR complex fire response procedure. The condition will be repaired during future equipment outages at the earliest opportunity. | 05000277/LER-2014-001 | |
| ENS 47442 | 16 November 2011 00:52:00 | 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | High Pressure Coolant Injection Steam Supply Valve Cable Unprotected During Postulated Fire | On 11/15/2011 at 1952 (EST), while performing a Fire Protection Program review, it was determined that one of the 'Multiple Spurious Operation' (MSO) modifications implemented during the P3R18 refueling outage adversely impacted Peach Bottom's fire safe shutdown analysis conclusions. New cabling that was routed for the Unit 3 High Pressure Coolant Injection (HPCI) system steam supply valve lacks appropriate fire barrier protection in the event of a postulated fire-induced damage to this cable. This cable is routed through a fire area in which the only credited and protected method of reactor level control for a fire in this area is HPCI. Postulated fire-induced damage in the cable could prevent the steam supply valve from opening, thereby causing the HPCI pump to be unavailable for an Appendix R fire. An hourly fire watch has been established as a compensatory action. The licensee has notified the NRC Resident Inspector. | High Pressure Coolant Injection |