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Entered date | Site | Region | Reactor type | Event description | |
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ENS 57221 | 10 July 2024 11:15:00 | Peach Bottom | NRC Region 1 | GE-4 | The following information was provided by the licensee via phone and email: At 0728 EDT on July 10, 2024, with Unit 2 in Mode 1 at 24 percent power, the reactor automatically scrammed due to a manual turbine trip. The (reactor) scram was not complex with all systems responding normally. Reactor vessel level reached the low-level set-point following the scram, resulting in valid Group 2 and Group 3 containment isolation signals. Due to the reactor protection system actuation while critical, this event is being reported as a four hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B) and an eight hour, non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A) for the Group 2 and Group 3 isolations. Operations responded using emergency operating procedures and stabilized the plant in Mode 3. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves. Unit 3 was not affected. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
ENS 56980 | 19 February 2024 18:44:00 | Peach Bottom | NRC Region 1 | GE-4 | The following information was provided by the licensee via email: At 1045 EST, on 2/19/2024, during a maintenance activity, a loss of all reactor building ventilation occurred on Unit 2. With no flow past the ventilation radiation monitors, the radiation monitors were inoperable to support their ability to perform primary and secondary containment isolation functions or start the standby gas treatment system. Reactor building ventilation was restored within 15 minutes. Due to this inoperability, the radiation monitor system was in a condition that could have prevented 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). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector will be notified.
Upon further investigation, it was verified that the reactor building and the refueling floor radiation monitors are not needed to control the release of radiation for events described in chapter 14 of the updated Final Safety Analysis Report. For the analyzed loss of coolant accident (LOCA), the primary and secondary signals for this purpose were available and unaffected by this event. The radiation monitors provide a tertiary redundant method that is not credited within the station analysis. For all other analyzed accidents, the signal provided by the radiation monitors is not needed, as the secondary containment isolation function and start of the standby gas treatment system are not credited. Additionally, the fuel handling accident was not credible during the time of the event because no activities were in progress on the refueling floor. Therefore, the threshold for reporting the issue as an event or condition that could have prevented the fulfillment of a safety function was not met. The NRC Resident Inspector has been notified. Notified R1DO (Jackson) |
ENS 56957 | 9 February 2024 15:07:00 | Peach Bottom | NRC Region 1 | GE-4 | 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) |
ENS 56936 | 29 January 2024 13:32:00 | Peach Bottom | NRC Region 1 | GE-4 | 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.
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. |
ENS 56753 | 21 September 2023 10:31:00 | Peach Bottom | NRC Region 1 | GE-4 | The following information was provided by the licensee via phone and email: A licensed operator had a confirmed positive test for alcohol during another entity's pre-access fitness-for-duty screening for unescorted access authorization. The individual's unescorted access at Peach Bottom Atomic Power Station has been denied. The NRC Resident Inspector has been notified. |
ENS 56513 | 9 May 2023 17:41:00 | Peach Bottom | NRC Region 1 | GE-4 | The following information was provided by the licensee via phone and email: At 1455 (EST) on Tuesday May 9, 2023, Peach Bottom Atomic Power Station (PBAPS) technical support center (TSC) ventilation system lost power. Power loss was caused by a tree down on the 361 transmission line. Power was not able to be restored within an hour. At 1639 (EST), power was restored to TSC ventilation, and capability was restored. This report is being submitted pursuant to 10 CFR 50.72(b)(3)(xiii) as a major loss of emergency preparedness capabilities due to a reduction in the effectiveness of the onsite TSC. NRC Resident has been notified. |
ENS 56358 | 6 February 2023 13:26:00 | Peach Bottom | NRC Region 1 | GE-4 | The following information was provided by Constellation via email: On 02/06/2023 at 0416 EST, the Constellation Emergency Response Organization (ERO) Notification Database System uploaded data files into the Mass Notification System (Everbridge) which is used to notify ERO personnel when activated. At 0630, the individual reviewing the uploaded files discovered that the data files did not upload properly and that Everbridge may not notify all ERO individuals within the required 10 minutes of system initiation. Constellation resolved the issue by 0752. During the time period of 0416 to 0752, control room operators would have been unaware that the ERO notification was not successful. Therefore, this issue constitutes a loss of offsite communications capability and is reportable under 10 CFR 50.72(b)(3)(xiii), 'The licensee shall notify the NRC as soon as practical and in all cases within eight hours of the occurrence of any event that results in a major loss of emergency assessment capability, offsite response capability, or offsite communications capability (e.g., significant portion of control room indication, Emergency Notification System, or offsite notification system).' This loss of offsite communications capability affected all Constellation nuclear stations. There was no impact on the health and safety of the public or plant personnel. Each affected station NRC Resident Inspectors have been or will be notified. |
ENS 56280 | 19 December 2022 12:50:00 | Peach Bottom | NRC Region 1 | GE-4 | The following information was provided by the licensee via email: This 60-day telephone notification is being made per the reporting requirements specified by 10 CFR 50.73(a)(1) and 50.73(a)(2)(iv)(A) for an invalid actuation of a primary containment isolation signal affecting more than one system. On November 11, 2022, at 2333 hours EST, Peach Bottom experienced an unplanned loss of the #343 Off-Site Startup Source. Due to the temporary loss of power during automatic bus transfers, several systems experienced Primary Containment Isolation System (PCIS) Group II and Group III (GP II/III) isolation signals. Plant Systems impacted by isolation valve closure included: Reactor Water Clean Up (RWCU), Containment Atmospheric Control (CAC), Traversing In-Core Probe (TIP) Purge, Primary Containment Floor and Equipment Drains, and the Instrument Nitrogen system. All equipment responded as designed. Plant conditions which initiate PCIS GP II isolation signals are Reactor Vessel Low Water Level, High Drywell Pressure, RWCU system High Flow or RWCU Non-Regenerative Heat Exchanger High Outlet Temperature. The PCIS GP III actuations are initiated by the Reactor Vessel Low Water Level, Primary Containment High Pressure, Reactor Building Ventilation High Radiation or Refuel Floor Ventilation High Radiation. At the time of the event, none of these actual plant conditions existed; therefore, the actuation of the PCIS was invalid. The loss of the #343 Off-Site Startup Source was caused by a failed printed circuit card in the programable logic controller (PLC) for the 3435 breaker. There is no time-based maintenance strategy for PLC replacement. The PLC circuit card was replaced, and the breaker restored to full qualification and service. Preventive maintenance strategy will be enhanced to address the identified vulnerability. The licensee has notified the NRC Resident Inspector. |
ENS 55899 | 16 May 2022 19:51:00 | Peach Bottom | NRC Region 1 | GE-4 | The following information was provided by the licensee via fax: Unit 2 experienced multiple electrical transients resulting in a Group I Primary Containment Isolation Signal (PCIS) isolation and subsequent unit reactor scram. Low reactor water level during the automatic scram caused PCIS Group II and III isolation signals. Following the PCIS Group I isolation, all main steam lines isolated. All control rods inserted and all systems operated as designed. The following additional information was obtained from the licensee via phone in accordance with Headquarters Operations Officers Report Guidance: Peach Bottom Unit 2 automatically scrammed from 100 percent power due to an electrical transient and subsequent PCIS Group I isolation (Main Steam Isolation Valve closure). Unit 2 lost main feedwater due to the PCIS Group I isolation, however, all other systems responded as expected following the scram. High Pressure Coolant Injection is maintaining pressure control while Condensate Pumps are maintaining inventory. The unit is currently stable and in Mode 3. Peach Bottom Unit 3's Adjustable Speed Drives were impacted by the electrical transients and the unit reduced power to 98 percent power. The NRC Resident Inspector was notified. |
ENS 55575 | 14 November 2021 08:50:00 | Peach Bottom | NRC Region 1 | GE-4 | At 0525 EST, November 14, 2021, "Unit 2 was manually scammed by operations due to lowering main condenser vacuum. This resulted in PCIS (primary containment Isolation system) Group II/III isolation signals. All control rods inserted, and all systems operated as designed. Unit 3 is unaffected and remains at 100 percent power in Mode 1. The Resident Inspector was notified. |
ENS 55261 | 17 May 2021 13:12:00 | Peach Bottom | NRC Region 1 | GE-4 | (Peach Bottom Atomic Power Station declared an unusual event due to a) "receipt of a single fire alarm in the Unit 2 drywell and the existence of the fire not verified in less than 30 minutes of alarm receipt." The NRC Resident Inspector and State and Local Authorities were notified. Notified DHS SWO, FEMA Operations Center, CISA Central, FEMA NWC (email), DHS Nuclear SSA (email), and FEMA NRCC SASC (email).
At 1355 EDT, the licensee terminated the notification of unusual event. The basis for termination was that the smoke has dissipated and there were no signs of fire. The licensee notified State and Local Authorities and the NRC Resident Inspector. Notified R1DO (Grieves), NRR EO (Miller), and IRD MOC (Grant). Notified DHS SWO, FEMA Operations Center, CISA Central, FEMA NWC (email), DHS Nuclear SSA (email), FEMA NRCC THD (email) and FEMA NRCC SASC (email).
Peach Bottom Atomic Power Station is retracting notification EN 55261, 'Peach Bottom - Unusual Event,' based on the following additional information not available at the time of the notification: Following a Unit 2 drywell inspection, analysis of temperature data, and evaluation of equipment in operation; it was concluded that a fire did not exist. The smoke's most likely apparent cause was the result of heating residual oil/grease in the drywell. Peach Bottom reported the condition and entry into the UE initially based on the available information at the time and to ensure timeliness with emergency declaration and reporting notification requirements. The licensee has notified the NRC Resident Inspector. Notified R1DO (Ferdas). |
ENS 55224 | 30 April 2021 07:38:00 | Peach Bottom | NRC Region 1 | GE-4 | On 4/29/21 at 2354 (EDT), an alarm was received for U2 HPCI Inverter Power Failure. (It was) identified that the High Pressure Coolant Injection (HPCI) flow controller had lost power due to a failure of an inverter. Without the flow controller, HPCI would not auto start to mitigate the consequences of an accident; thus, HPCI was declared inoperable. All other emergency core cooling systems and reactor core isolation cooling (RCIC) system remain operable. HPCI is a single train system with no redundant equipment in the same system; therefore, this failure is reportable as an event or condition that could have prevented fulfillment of a safety function needed to mitigate the consequences of an accident per 10CFR50.72(b)(3)(v)(d). The NRC Resident has been informed of this notification. |
ENS 54971 | 29 October 2020 15:12:00 | Peach Bottom | NRC Region 1 | GE-4 | 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. |
ENS 54917 | 28 September 2020 05:02:00 | Peach Bottom | NRC Region 1 | EN Revision Imported Date : 10/12/2020 LOSS OF TECHNICAL SUPPORT CENTER VENTILATION SYSTEM DUE TO PLANNED MAINTENANCE: This is an eight-hour, non-emergency notification for a loss of Emergency Assessment Capability. This event is reportable in accordance with 10 CFR 50.72(b)(3)(xiii) because the planned maintenance affects the functionality of an emergency response facility. Planned maintenance activities are being performed on 09/28/20 to the Peach Bottom Atomic Power Station (PBAPS) Technical Support Center (TSC) HVAC. The work includes replacement of supply fan and roof-top unit. Work is scheduled to complete on 10/11/20. If an emergency is declared requiring PBAPS TSC activation during this period, the PBAPS TSC will be staffed and activated using existing Emergency Preparedness (EP) procedures. If the PBAPS TS becomes uninhabitable due to radiological, or other conditions, the TSC Station Emergency Director will relocate the TSC staff to an alternate location in accordance with EP procedures. The Emergency Response Organization team has been notified of the maintenance and the possible need to relocate during an emergency. The NRC Resident Inspector will be notified by the licensee.
An eight-hour, non-emergency notification for a loss of Emergency Assessment Capability was made on 9/28/20 under Event Notification 54917 for planned maintenance activities to the Peach Bottom Atomic Power Station (PBAPS) Technical Support Center (TSC) ventilation system. This event was reportable in accordance with 10 CFR 50.72(b)(3)(xiii) because the planned maintenance affected the functionality of an emergency response facility. This update to EN 54917 is to notify applicable stakeholders that, following satisfactory completion of the planned supply fan and roof-top unit replacement work, the PBAPS TSC ventilation system has been returned to service with no remaining work or outstanding deficiencies related to this work. The licensee has notified the NRC Resident Inspector. Notified R1DO (Lally). | |
ENS 54829 | 11 August 2020 20:22:00 | Peach Bottom | NRC Region 1 | At 1334 EDT on Tuesday August 11th, the Peach Bottom Atomic Power Station (PBAPS) Technical Support Center (TSC) Ventilation System lost power due to a trip of the Station Blackout (SBO) electric power supply breaker. The trip was due to a fault at the Conowingo Dam and Conowingo was not able to realign electric power to the SBO within an hour. Power restoration is complete and TSC Ventilation was restored at 1725 EDT. This report is being submitted pursuant to 10CFR 50.72(b)(3)(xiii) as a Major Loss of Emergency Preparedness Capabilities due to a reduction in the effectiveness of the Onsite Technical Support Center (TSC). The NRC Resident Inspector has been notified. | |
ENS 54820 | 6 August 2020 13:10:00 | Peach Bottom | NRC Region 1 | This report is being made as required by 10 CFR 50.73(a)(2)(iv)(A) to describe an automatic actuation of containment isolation valves in more than one system. Because the actuation was invalid, this 60-day telephone notification is being made instead of a written LER (licensee event report), in accordance with 10 CFR 50.73(a)(1). On 06/08/2020, at approximately 0424 EDT, a trip of the Unit 3 'A' reactor protection system (RPS) MG-Set resulted in a partial activation of the primary containment isolation system and inboard containment isolation valves closed in multiple systems. All affected Group III containment isolation valves were verified to be closed. It was determined that the normal power supply for the Unit 3 'A' RPS had failed. Power was transferred from the normal to the alternate source and the RPS 'A' channel was reset. Investigation determined that the 3A RPS MG Set motor contactor coil winding had failed due to an internal short circuit. The motor contactor has been replaced. The containment isolation was not due to actual plant conditions or parameters meeting design criteria for containment isolation. Therefore, this is considered to be an invalid actuation. The NRC Resident Inspector has been informed of this notification. | |
ENS 54340 | 21 October 2019 01:23:00 | Peach Bottom | NRC Region 1 | While Unit 3 was shutting down for 3R22 refueling outage, the mode switch was taken to shutdown position which is a manual scram signal. The manual scram signal was not received from the mode switch. A subsequent manual scram was inserted with the use of the manual scram push buttons. The Unit 3 reactor is shutdown with all rods inserted. Unit 2 was unaffected by the event and remains in Mode 1 at 100 percent power. The licensee notified the NRC Resident Inspector, Pennsylvania and Maryland State Agencies, local government. A media press release is planned. Notified DHS SWO, FEMA Operations Center, DHS NICC, FEMA NWC (email), DHS Nuclear SSA (email), and FEMA NRCC SASC (email), FEMA Region 3 Watch Office (email).
Conditions no longer meet an Emergency Actuation Level and will not deteriorate. Unit 3 reactor is shutdown with all control rods fully inserted. The NOUE was terminated at 0230 EDT." The licensee notified the NRC Resident Inspector, Pennsylvania and Maryland State Agencies, local government. Notified the R1DO (Jackson), NRR EO (Miller), IRDMOC (Gott), R1RA (Lew via email), NRR (Nieh via email), DHS SWO, FEMA Operations Center, DHS NICC, FEMA NWC (email), DHS Nuclear SSA (email), and FEMA NRCC SASC (email), FEMA Region 3 Watch Office (email). | |
ENS 54330 | 15 October 2019 19:14:00 | Peach Bottom | NRC Region 1 | On 10/15/19 at 1210 (EDT) Peach Bottom discovered a degraded spring hanger (23DBN-H39) associated with Unit 3 High Pressure Coolant Injection (HPCI) system. The hanger is located downstream of MO-3-23-14 HPCI Steam Supply Valve before the HO-3-23-4513 Turbine Stop Valve. A review of the piping and support design analysis were performed and concluded the U3 HPCI turbine inlet nozzle would potentially exceed its allowable stresses. Following Engineering review, U3 HPCI was declared inoperable at 1743 (EDT). This report is being submitted pursuant to 10 CFR 50.72(b)(3)(v)(D). The NRC Resident Inspector has been notified.
Additional evaluation by Engineering personnel determined that the degraded spring hanger would have no adverse effect on the subject piping or HPCI turbine nozzle structural integrity. Pressure, deadweight, and seismic stresses were within allowable limits. Non-destructive examination (NDE) of the piping and nozzle was performed to identify any signs of cracking, yielding, or defects. NDE results were satisfactory. The degraded spring hanger did not effect the Unit 3 HPCI system operability and this call is being retracted. The NRC Resident Inspector has been notified. Notified R1DO (Cahill). | |
ENS 53933 | 14 March 2019 17:08:00 | Peach Bottom | NRC Region 1 | A licensed employee was determined to be under the influence of alcohol during a random test. The employee's access to the plant has been suspended pending an investigation. The licensee notified the NRC Resident Inspector. | |
ENS 53630 | 30 September 2018 15:29:00 | Peach Bottom | NRC Region 1 | On Sunday, September 30, 2018, at 1130 EDT, an automatic scram was received on U3 following a loss of two condensate pumps. Following the reactor scram, water level lowered from normal level of 23" to below 1" which resulted in automatic Group II and Group III isolations. Reactor water level lowered to -48" which resulted in initiation of the High Pressure Coolant Injection and Reactor Core Isolation Cooling systems. Reactor water level and reactor pressure have been restored to their normal bands. All systems responded properly to the event. Unit 3 remains in Mode 3 with reactor pressure being controlled on the turbine bypass valves. The cause and details of the event are under investigation. This report is being made in accordance with 10 CFR 50.72(b)(2)(iv)(A), 10 CFR 50.72(b)(2)(iv)(B), and 10 CFR 50.72(b)(3)(iv)(A). All control rods inserted. Decay heat is being removed via the main condenser. The NRC Resident Inspector has been notified. A notification to the media and a press release were made. Unit 2 was unaffected and continues coastdown to refueling. | |
ENS 53617 | 21 September 2018 22:04:00 | Peach Bottom | NRC Region 1 | 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). | |
ENS 53594 | 11 September 2018 17:14:00 | Peach Bottom | NRC Region 1 | On September 11, 2018 the Technical Support Center (TSC) ventilation was discovered to be non-functional during system testing. At 1310 EDT, an air leak was identified that prevented the modulating dampers to operate as designed to maintain required pressure. The air leak was not able to be repaired within a 60 minute period. This failure affected the ability of the TSC ventilation system to maintain adequate radiological habitability in the event of an emergency with an airborne radiological release. All other capabilities of the TSC are unaffected by this emergent condition. The air leak has been repaired and post maintenance testing was completed satisfactory at 1654 (EDT), restoring the TSC ventilation to a functional condition. This notification is being made in accordance with 10 CFR 50.72(b)(3)(xiii) due to the potential loss of an emergency response facility because of the unavailability of the ventilation system. The NRC Resident Inspector has been notified. | |
ENS 53265 | 15 March 2018 22:08:00 | Peach Bottom | NRC Region 1 | GE-4 | 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. |
ENS 53053 | 4 November 2017 14:00:00 | Peach Bottom | NRC Region 1 | GE-4 | A licensed employee had a confirmed positive test for a controlled substance during a random fitness-for-duty test. The employees plant access has been placed on administrative hold. The NRC Resident Inspector has been notified. |
ENS 53031 | 23 October 2017 09:35:00 | Peach Bottom | NRC Region 1 | GE-4 | 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. |
ENS 52961 | 11 September 2017 15:00:00 | Peach Bottom | NRC Region 1 | GE-4 | This report is being made as required by 10 CFR 50.73(a)(2)(iv)(A) to describe an automatic actuation of containment isolation valves in more than one system. Because the actuation was invalid, this 60-day telephone notification is being made instead of a written LER (Licensee Event Report), in accordance with 10 CFR 50.73(a)(1). On 07/14/17, at approximately 1453 hours (EDT), an electrical transient occurred due to an off-site lightning strike that de-energized one of the station's two qualified off-site power sources. This resulted in an automatic fast transfer of four 4 kV electrical buses to the alternate off-site source. The fast transfer occurred as designed without complications. The loss of power had numerous impacts on plant equipment that occurred in accordance with plant design, including a Group 2 primary containment isolation on both units. The Group 2 isolation affected multiple systems, including Reactor Water Cleanup, Instrument Nitrogen, and the Drywell Floor Drain. The fault on the off-site transmission line immediately cleared after the lightning strike and at 1457 hours (EDT) the transmission system operator gave the station permission to reclose the breaker to the off-site source. Following system restorations and equipment walkdowns, plant operators re-established normal connections to the off-site source on 7/14/17 at 2322 hours (EDT) in accordance with station procedures. The containment isolation occurred as a result of the loss of an off-site power source and was not due to actual plant conditions or parameters meeting design criteria for containment isolation. Therefore, this is considered to be an invalid actuation. The NRC Resident Inspector has been informed of this notification. |
ENS 52909 | 16 August 2017 15:41:00 | Peach Bottom | NRC Region 1 | GE-4 | On 8/16/2017, at 1039 (EDT), an un-planned trip of the Peach Bottom Station Blackout Transformer 34.5 kV feeder breaker 1005 and a loss of the 191-00 line occurred causing a loss of power to Unit 1 and the TSC. Power was not restored to the TSC or the ventilation system within 1 hour. Power was subsequently restored to the TSC at 1207 hours (EDT) and the ventilation system was restored to available. This report is being submitted pursuant to 10CFR50.72(b)(3)(xiii) as a Major Loss of Emergency Preparedness Capabilities due to a reduction in the effectiveness of the Onsite Technical Support Center (TSC). The NRC Resident Inspector has been informed of this notification. |
ENS 52478 | 9 January 2017 16:56:00 | Peach Bottom | NRC Region 1 | GE-4 | 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. |
ENS 52419 | 9 December 2016 05:29:00 | Peach Bottom | NRC Region 1 | GE-4 | On 12/08/16 at approximately 2237 (EST), the Unit 2 HPCI (High Pressure Coolant Injection) system failed to meet surveillance testing requirements for achieving rated flow at greater than or equal to a minimum test pressure established per the surveillance. Operations declared the HPCI system inoperable and entered Technical Specification 3.5.1 Condition C for HPCI 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 10 CFR 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 3951006). Investigation of the exact failure condition is in progress so that repairs can be made. At the surveillance flow of 5,000 gpm, the system was approximately 80 psi below the required pressure of 1,278 psi. Technical Specification 3.5.1, Condition C, is a 14-day Limiting Condition of Operation. The NRC Resident Inspector will be notified.
The licensee provided the following information as the basis for retracting this report: This is a retraction of an event notification made on 12/09/16 at 0529 EST (EN #52419). This event was initially reported pursuant to 10 CFR 50.72(b)(3)(v)(D) as a condition that, at the time of discovery, was believed to have prevented the fulfillment of the High Pressure Coolant Injection (HPCI) system safety function. On 12/08/16 at 2237 EST, the Unit 2 HPCI system was declared inoperable due to failing to meet surveillance testing requirements for achieving rated flow at greater than or equal to a minimum test pressure established per the surveillance. Prompt troubleshooting was performed and it was determined that an adjustment to the HPCI turbine governor control system was required. This adjustment was performed and HPCI was returned to an operable status on 12/09/16. Subsequent to this occurrence, Engineering has completed an evaluation that concluded that HPCI was capable of fulfilling its safety function and that the associated Technical Specification (TS) Surveillance Requirement (SR) 3.5.1.8 was met. The evaluation concluded that HPCI was degraded, but met the threshold for TS operability. The NRC Senior Resident has been informed of this retraction." Notified R1DO (Kennedy). |
ENS 52264 | 27 September 2016 00:20:00 | Peach Bottom | NRC Region 1 | GE-4 | On 9/26/16 at approximately 1845 EDT, investigation of an identified water leak on one of the two Unit 3 HPCI turbine exhaust drains to the drain pot determined that there was through wall leakage of approximately 2 drops per minute. Operations promptly declared the HPCI system inoperable and entered Technical Specification 3.5.1 Condition C for HPCI 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 10 CFR 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 2720241). Investigation of the exact flaw location is in progress so that repairs can be made. The NRC resident has been informed of this notification. |
ENS 51962 | 27 May 2016 09:22:00 | Peach Bottom | NRC Region 1 | GE-4 | This 60-day report, as allowed by 10 CFR 50.73(a)(1), is being made pursuant to 10 CFR 50.73(a)(2)(iv)(A) to describe an unplanned, invalid actuation of containment isolation valves in more than one system. On 3/28/16, at approximately 1320 (EDT), a loss of power occurred on the Unit 2 E124 480 volt load center due to an equipment operator inadvertently opening the main feed breaker during the process of applying a clearance to de-energize the E124-P-A motor control center for planned maintenance. Loss of the E124 load center resulted in Group II and Group III primary containment isolations due to an invalid ESF actuation signal. Systems impacted by the containment isolations included containment instrument nitrogen, containment atmospheric monitoring, reactor water cleanup, and secondary containment. Balance of plant impacts included partial loss of feedwater heating and a reduced condenser vacuum. Reactor power lowered to 86% as a result of the event and further decreased to approximately 80 percent when re-establishing the 3A, 4A and 5A feedwater heaters. Following direction from the control room, the E124 main feed breaker was promptly re-closed by equipment operators. Affected equipment was restored to its normal or planned configuration and containment isolations were reset at 1406. The containment isolation signal was generated as a result of the loss of power to the E124 load center and was not due to actual plant conditions or parameters meeting design criteria for containment isolation. Therefore, this is considered to be an invalid actuation. The licensee has notified the NRC Resident Inspector. |
ENS 51630 | 31 December 2015 13:15:00 | Peach Bottom | NRC Region 1 | GE-4 | On 12/31/15, at approximately 0630 hours (EST), during shift turnover panel walk-downs, a licensed Unit 3 reactor operator identified that the High Pressure Coolant Injection (HPCI) flow controller output indicated a downscale condition. The controller was in automatic with the set point at 5000 gpm, which would typically indicate a controller output value of 100%. HPCI was not in operation and is a standby system. Operations promptly declared the HPCI system inoperable and entered Technical Specification Condition C for HPCI 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 10 CFR 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 2606215). Maintenance troubleshooting of the flow controller loop has identified a failed component and repair activities are in progress. The NRC Resident Inspector has been informed of this notification. |
ENS 50571 | 29 October 2014 12:50:00 | Peach Bottom | NRC Region 1 | GE-4 | 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. |
ENS 50395 | 23 August 2014 20:19:00 | Peach Bottom | NRC Region 1 | GE-4 | At 13:00 (EDT) on Saturday, August 23, 2014, both trains of the Peach Bottom Atomic Power Station (PBAPS) Emergency Service Water (ESW) System were declared inoperable on Unit 2 and Unit 3, due to a pin-hole, through wall piping leak. In accordance with 10CFR 50.72(b)(3)(v), this event is being reported as an event or condition that could have prevented the fulfillment of the safety function of systems that are needed to shut down the reactor and maintain it in a safe shutdown condition, remove residual heat and mitigate the consequences of an accident. At 19:22 (EDT), the station received verbal approval of a Notice of Enforcement Discretion (NOED) request. Simultaneously, the station is preparing an evaluation to support an emergent-relief request. The NRC Resident Inspector has been notified. |
ENS 50185 | 10 June 2014 19:38:00 | Peach Bottom | NRC Region 1 | GE-4 | At 1600 EDT on June 10, 2014, a non-work related on-site fatality as a result of natural causes occurred at the Peach Bottom Atomic Power Station. The fatality was not related to the health and safety of the public or on-site personnel. Specifically, a contract truck driver was found non-responsive in a truck in the parking lot. The individual was outside of the Radiological Controlled Area and no radioactive material or contamination was involved. The location of the parking lot is outside of the Protected Area but within the owner controlled area. An Event of Potential Public Interest has been completed. Peach Bottom Atomic Power Station will make notifications due to a fatality on-site. This ENS notification is in response to a notification to another government agency in accordance with 10CFR50.72(b)(2)(xi). The licensee notified the NRC Resident Inspector. The licensee notified the Emergency Management Agencies in Pennsylvania and Maryland, the Pennsylvania State Police, as well as the surrounding counties. |
ENS 50128 | 21 May 2014 17:39:00 | Peach Bottom | NRC Region 1 | GE-4 | 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. |
ENS 50089 | 6 May 2014 12:50:00 | Peach Bottom | NRC Region 1 | GE-4 | This 60-day report, as allowed by 10CFR 50.73(a)(1), is being made pursuant to 10CFR 50.73(a)(2)(iv)(A) to describe an unplanned, invalid actuation of an emergency service water system. On 3/9/14, at approximately 1536 EST, the E2 Emergency Diesel Generator (EDG) was started for a post maintenance operability test. The 'A' safety-related Emergency Service Water (ESW) pump was being used to provide cooling to the EDG. At approximately 1613 EST and 1622 EST, unexpected automatic starts of the 'B' ESW pump and the non-safety related single train Emergency Cooling Water (ECW) pump occurred. The EDG run was terminated at 1622 EST to investigate the cause of the unexpected starts. It was determined that a failed angle drive adaptor resulted in invalid input to the speed switch, which resulted in the unplanned starts of the 'B' ESW pump and the ECW pump. Except for the failure of the angle drive adaptor, all systems and equipment operated as expected. The NRC resident has been informed of this notification. |
ENS 49864 | 1 March 2014 14:19:00 | Peach Bottom | NRC Region 1 | GE-4 | At 1125 (EST) on Saturday, March 1st, 2014, the Peach Bottom Atomic Power Station Main Stack Wide Range Radiation monitor was declared inoperable due to a loss of sample flow. This event is being reported as a loss of emergency assessment capability in accordance with 10 CFR 50.72(b)(3)(xiii). The inoperability would impact the ability to declare an Emergency Action Level at a level of an Alert or higher based on Main Stack radiation release. The NRC Resident Inspector has been notified. |
ENS 49810 | 9 February 2014 08:10:00 | Peach Bottom | NRC Region 1 | GE-4 | On 02/09/2014, at 0100 (EST), a major portion of Peach Bottom Atomic Power Station's (PBAPS) offsite communication capability was discovered to be non-functional due to an offsite communications equipment failure outside the control of PBAPS. Peach Bottom continues to investigate and resolve the cause of this loss of offsite communications. Peach Bottom Main Control Room ENS and offsite communication lines have been restored and are currently available. The Technical Support Center is limited to satellite phones for offsite communications. On-site communications were not affected. This report is being submitted pursuant to 10CFR 50.72(b)(3)(xiii) as a result of a major loss of offsite communications capability. The NRC (Resident Inspector) has been informed of this notification. |
ENS 49480 | 29 October 2013 05:01:00 | Peach Bottom | NRC Region 1 | GE-4 | At 0500 (EDT) Tuesday, October 29, the Peach Bottom Atomic Power Station (PBAPS) main stack radiation monitors will be removed from service for planned preventative maintenance activities on the flow elements. This maintenance is scheduled to be worked continuously until completion to minimize out of service time. The planned main stack radiation monitor outage is scheduled to be completed within 13 hours. Periodic gas sampling will be performed in accordance with the offsite dose calculation manual while the monitors are out of service. The NRC Resident Inspector has been notified. There are no follow-up written reports required for this event.
This is an update to notification #49480. The out of service duration has been extended from the original estimated 13 hours due to work scope taking longer than expected with fatigue rule compliance requirements. The radiation monitor maintenance has been completed and the components have been restored to service, however, the post maintenance testing will be delayed until this morning (10/30/13) when the necessary component expert resource is next available. Periodic gas sampling remains in effect in accordance with the Off Site Dose Calculation Manual. The licensee will notify the NRC Resident Inspector. Notified R1DO (Krohn). |
ENS 49400 | 1 October 2013 14:11:00 | Peach Bottom | NRC Region 1 | GE-4 | Exelon Generation has successfully tested the new emergency warning sirens installed in the 10-mile radius surrounding Peach Bottom Atomic Power Station. With approval from the Federal Emergency Management Agency (FEMA), Exelon Generation began transitioning to the new sirens on 10/1/13. At 11:31 am EDT, during the transition, a vendor technician inadvertently actuated the York County emergency warning sirens. The Sirens went through a full sounding of three minutes and then stopped alarming. The alarming sirens were not due to any condition at Peach Bottom. Exelon and York County have investigated the issue and found that the system worked properly. The cause of the inadvertent actuation was that a test signal was not given sufficient time to clear prior to putting the system in service after testing. The NRC Resident Inspector has been informed. The licensee will issue a press release. |
ENS 48455 | 30 October 2012 03:20:00 | Peach Bottom | NRC Region 1 | GE-4 | Peach Bottom Atomic Power Station Control Room was notified of a loss of greater than 25% of sirens after severe storms in the area associated with Hurricane Sandy. Thirty-one (31) of 97 Emergency Planning Zone (EPZ) sirens are currently unavailable in Lancaster, York, Cecil and Harford Counties. Actions are currently being taken to restore unavailable sirens. The licensee notified the NRC Resident Inspector.
Currently 12 of 97 sirens remain inoperable. The licensee will inform state and local agencies and the NRC Resident Inspector. Notified R1DO (Caruso). |
ENS 48376 | 4 October 2012 16:37:00 | Peach Bottom | NRC Region 1 | GE-4 | The 'A' Main Control Room Emergency Ventilation System (MCREV) fan failed to automatically start when placed in service at 0959 EDT on 10/4/12. The `B' fan was available at the time of the initiation, but was inoperable due to E-42 Emergency 4kV Bus outage. Both MCREV fans inoperable is an entry into Technical Specification 3.7.4 Condition E which requires Unit 3 to be Mode 3 in 12 hours. Unit 2 was not in a mode of applicability at the time of the event (Unit 2 is defueled). This issue is being reported under 10 CFR 50.72(b)(3)(v)(D) for an event that could have prevented the fulfillment of a safety function - mitigate the consequences of an accident. The 'A' MCREV fan was restored to an operable status at 1237 EDT on 10/4/12 and the Technical Specification Action was exited. The NRC Resident Inspector has been notified. |
ENS 48297 | 11 September 2012 11:11:00 | Peach Bottom | NRC Region 1 | GE-4 | This ENS (report) is being voluntarily issued to notify the NRC that voluntary communications were made to offsite agencies this morning between 0700 and 0830 (EDT) due to an event of potential public interest. At approximately 1 a.m. on September 1, 2012, Peach Bottom outage workers on the Unit 2 refuel floor were disassembling the reactor head vent when steam discharged from the flange, causing a small but detectable amount of airborne contamination that was contained in the building. All workers were wearing the proper protective equipment and no significant personal (personnel) exposure has been reported. As a precaution, employees were asked to temporarily leave the area for onsite evaluation while radiation protection technicians investigated. Approximately 50 workers were impacted by the radiological airborne event at Peach Bottom and had to stay over shift for radiological monitoring. In accordance with station Radiological procedures, affected personnel are being monitored and as required bioassay is being conducted. Radiation monitors in the reactor building initially detected the airborne contamination, but all have returned to normal levels. This event resulted in no significant impact to the health and safety of our workers or the public. The station made voluntary notifications to the NRC Senior Resident, the State Bureau of Radiation Protection and state and local stakeholders. This issue has been entered into the site Corrective Action Program for evaluation and implementation of further corrective actions. |
ENS 47907 | 8 May 2012 12:33:00 | Peach Bottom | NRC Region 1 | GE-4 | This 60-day report, as allowed by 10 CFR 50.73(a)(1), is being made under the reporting requirement in 10CFR50.73(a)(2)(iv)(A) to describe an unplanned, invalid actuation of specified systems, specifically the Unit 2 Primary Containment Isolation System (PCIS). On 3/13/12, at approximately 1604 hours, Unit 2 experienced an invalid PCIS partial isolation. An equipment operator was in the process of making an adjustment to the Reactor Protection System (RPS) MG Set output voltage during daily rounds. As the rheostat was beginning to be rotated to increase the voltage, output voltage quickly dropped below the MG Set undervoltage trip setpoint. The BC757B and BC757D MG Set output breakers opened, resulting in the loss of the 2B RPS bus causing a half scram. The half scram signal resulted in closure of the instrument nitrogen primary containment isolation valve, secondary containment normal ventilation isolation valves and start of the 'B' Standby Gas Treatment supply fan. The invalid PCIS isolation was a result of the failure of the voltage adjustment rheostat for the MG Set output voltage. This issue has been entered into the site Corrective Action Program (AR 1340452) for evaluation and implementation of further corrective actions. The NRC Resident Inspector has been informed of this notification. |
ENS 47786 | 29 March 2012 04:04:00 | Peach Bottom | NRC Region 1 | GE-4 | At 0400 (EDT) on Thursday March 29th, the Peach Bottom Atomic Power Station (PBAPS) Technical Support Center (TSC) supply and exhaust fans will be removed from service for planned preventative maintenance activities on the exhaust fan. This maintenance is scheduled to be worked continuously until completion to minimize out of service time. The planned TSC ventilation outage is scheduled to be completed within 14 hours. If TSC staffing is required, it will take a maximum of 4 hours to return the ventilation system back to an operable status. The licensee has notified the NRC Resident Inspector.
The planned maintenance is complete and the TSC was restored back to service at 1530 EDT. The NRC Resident Inspector has been informed. Notified R1DO (Newport). |
ENS 47581 | 10 January 2012 00:55:00 | Peach Bottom | NRC Region 1 | GE-4 | On January 09, 2012 the Technical Support Center(TSC) ventilation was discovered to be non-functional during system testing. At 1722 hours (EST), it was identified that control power was lost to four motor operated dampers. Investigation revealed that a control power fuse was blown. In addition, the TSC ventilation Supply Fan (AHU-1) was identified to have one of two fan belts failed. The fuses were replaced at 19:45 (EST) and the system was restored to service. However, the system has been removed from service this evening to replace the fan belts. An update will be provided when the system is restored to full functionality. The licensee has notified the NRC Resident Inspector.
Maintenance personnel installed two new belts on AHU-1 and aligned the motor/fan sheaves to ensure correct operation. TSC ventilation has been restored to the normal condition. The licensee will notify the NRC Resident Inspector. R1DO (Trapp) notified. |
ENS 47442 | 15 November 2011 22:19:00 | Peach Bottom | NRC Region 1 | GE-4 | 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. |
ENS 47286 | 21 September 2011 22:48:00 | Peach Bottom | NRC Region 1 | GE-4 | On 9/21/11 at 10:20 a.m. during the performance of a simulated loss of offsite power testing off the E33 4KV emergency bus, an unplanned start of the E3 Emergency Diesel Generator (EDG) occurred due to a valid bus under voltage signal caused by a relay malfunction. The bus being tested was inoperable in support of the test and was not carrying any required safety system loads at the time of the event. The EDG was secured and troubleshooting initiated. The initial determination was the EDG actuation was from an invalid signal but following further review it was determined that the relay malfunction had caused an untimely bus transfer that resulted in a valid 4KV bus under voltage condition. The NRC Resident Inspector has been notified. |
ENS 47273 | 18 September 2011 08:52:00 | Peach Bottom | NRC Region 1 | GE-4 | A worker was transported to an off-site medical facility due to a work-related hand injury. The individual was not contaminated. The individual's left hand work glove was found to be contaminated. The individual remains under the care of physicians and all contaminated material was safely collected and is being transported back to Peach Bottom Atomic Power Station as required. A licensee health physics employee accompanied the worker to the hospital. There was no spread of contamination in the ambulance or at the hospital. The licensee notified the NRC Resident Inspector and will be notifying the Pennsylvania Emergency Management Agency and local authorities. |