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| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 54971 | 29 October 2020 14:30:00 | 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | Through-Wall Leakage Identified on Reactor Coolant System Pressure Boundary During Testing | At 1030 EDT on Thursday, October 29, 2020, during the performance of Peach Bottom Atomic Power Station leakage testing of the reactor pressure vessel and associated piping, a through-wall leak (non-isolable) was identified on an instrument line connected to the N16A nozzle. The reactor will be maintained shutdown until pipe repairs and testing are complete. The NRC resident inspector has been informed. | Reactor Coolant System Reactor Pressure Vessel | |
| ENS 53617 | 21 September 2018 04:00:00 | 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 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | High Pressure Coolant Injection System Inoperable | On 9/21/18, at 1755 EDT, Peach Bottom Atomic Power Station Unit 3 declared the High Pressure Coolant Injection system (HPCI) inoperable due to an inoperable differential pressure indicating switch (DPIS). The DPIS is used to isolate the HPCI system when there is a high steam line flow condition. Operations declared the HPCI system inoperable and entered Technical Specification 3.5.1 Condition C for HPCI being inoperable. Technical Specification 3.3.6.1 was also entered for HPCI instrumentation being inoperable. Other standby systems (Reactor Core Isolation Cooling and Low Pressure Emergency Core Cooling Systems) are OPERABLE. HPCI is a single train system. Therefore, per NUREG-1022, this condition is being reported pursuant to 10CFR 50.72(b)(3)(v)(D) as a condition that could have prevented the fulfillment of the safety function of a system required to mitigate the consequences of a design event. This condition has been entered into the corrective action program (IR 4175355). Investigation of the exact cause of the indication issue is in progress. The NRC Resident has been informed of this notification.
On 09/22/18 at 0955 EDT, RCS (Reactor Coolant System) pressure boundary leakage was identified as the cause of the HPCI high steam flow indication issue. Technical Specification 3.4.4 was entered which will require the initiation of a nuclear plant shutdown. This indicates a degradation of a principal safety barrier. Current Unit 3 reactor power is 35%. This condition is being reported pursuant to 10 CFR 50.72(b)(2)(i) and 50.72(b)(3)(ii). This condition is being tracked in the corrective action program (IR 4175355). The NRC Resident has been informed". Peach Bottom will be notifying State and local agencies regarding the event. Notified the R1DO (Greives). | High Pressure Coolant Injection Reactor Core Isolation Cooling Emergency Core Cooling System | |
| ENS 53031 | 23 October 2017 08:00:00 | 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | Leakage Identified on One Inch Line Socket Weld for the B Recirculation Pump | On Monday, October 23, 2017, with PBAPS (Peach Bottom Atomic Power Station) Unit 3 in Mode 3 at the beginning of a refueling outage, personnel entered the drywell to perform an inspection. At approximately 0400 (EDT), leakage was identified on a one-inch diameter instrument line socket weld for the 'B' recirculation pump. Because the leak was misting, the leakage rate could not be quantified. However, Unit 3 reactor coolant unidentified leakage prior to plant shutdown was 0.18 gpm. This line is considered part of the primary coolant pressure boundary. This event is being reported as an occurrence of an event or condition that results in the condition of the nuclear power plant, including its principal safety barriers being seriously degraded under 10 CFR 50.72(b)(3)(ii). The Station is preparing an evaluation and repair plan at this time. The NRC Resident Inspector has been notified. | 05000278/LER-2017-001 | |
| ENS 50571 | 29 October 2014 15:20:00 | 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | Maximum Allowable Primary Containment Leakage Rate Exceeded | This notification is to report a condition involving higher than allowable through-seat leakage of two redundant feedwater system check valves (28A and 96A). Unit 2 is currently shut down and primary containment is not required to be operable. Therefore, there is currently no safety impact due to this discovered condition. This leakage was identified as a result of planned local leak rate testing of the feedwater primary containment isolation valves for the 'A' feedwater line being performed during the current P2R20 refueling outage. At approximately 1100 EDT, Engineering determined that the primary containment penetration pathway leakage through the redundant check valves resulted in a condition where the maximum allowable primary containment leakage rate (La) was exceeded. In accordance with NUREG-1022, Rev. 3, Event Report Guidelines 10 CFR 50.72 and 50.73, Section 3.2.4, this occurrence is an example of a reportable condition. Therefore, this notification is being made pursuant to 10CFR 50.72(b)(3)(ii)(A). This condition has been entered in the plant corrective action program (IR 2402909). The NRC Resident Inspector has been informed of this notification. | Feedwater Primary containment | 05000277/LER-2014-003 |
| ENS 42889 | 7 October 2006 21:50:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Technical Specification Required Shutdown Due to Loss of Primary Containment Integrity | At 17:50, on 10/07/2006, the Peach Bottom Atomic Power Station identified a crack approximately 4 inches long on a Unit 2, Reactor Core Isolation Cooling (RCIC) test line, as the line penetrates the Suppression Pool of Primary Containment. The degraded piping represents a loss of primary containment integrity, placing one of the principle safety barriers in a 'Seriously Degraded' condition as defined by 10CFR50.72 (b)(3)(ii)(A). This condition required a Reactor Shutdown per the plants Technical Specifications (TS) (TS 3.6.1.1). Unit 2 was manually scrammed, at 20:16, in order to shutdown the reactor and place the unit in Mode 3 per the Technical Specifications. The TS required shutdown is reportable per 10CFR50.72(b)(2)(i). The unplanned reactor scram is reportable per 10CFR50.72(b)(2)(iv)(B). The reactor scram and resultant Emergency Safety Feature actuations were completed as required. In addition, the loss of primary containment integrity represents a condition that 'could have prevented the fulfillment of a safety function of a structure required to control the release of radioactive material' and/or 'mitigate the consequences of an accident.' This is reportable per 10CFR50.72(b)(3)(v)(C) and (D). Unit 2 is currently shutdown, Mode 3, with an RPV cooldown in progress, with plans to Enter Mode 4 by 02:00 on 10/08/06. All control rods fully inserted on the Manual Reactor Scram. The reactor is currently being fed from the condensate system with decay heat being removed to the condenser via the MSL drains. The electric plant is in a normal shutdown lineup. See EN # 42887 for related NOTICE OF UNUSUAL EVENT. Additional 10 CFR Section not listed above: 50.72(b)(3)(v)(D) ACCIDENT MITIGATION The licensee notified the NRC Resident Inspector. | Reactor Core Isolation Cooling Primary containment Control Rod | |
| ENS 42003 | 20 September 2005 09:00:00 | 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | Degraded Condition - Small Leak on Rhr Injection Drain Line | After shutting down for refueling outage, a small leak was discovered on a 1-inch drain line for the 'A' Loop RHR injection line. This leak is at a weld. Tech Spec 3.4.4 was entered for RCS Operational Leakage due to potential Class I pressure boundary leakage. This report is being made IAW 10CFR50.72(b)(3). The licensee will notify the NRC Resident Inspector. |