Semantic search
| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 55522 | 14 October 2021 17:20:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Traversing IN-CORE Probe a Ball Valve Inoperable | At 1320 EDT, during a Traversing In-Core Probe (TIP) run for a scheduled Local Power Range Monitors (LPRM) calibration, it was reported to the Main Control Room that TIP A would not fully retract to the In-Shield position. With TIP A unable to fully retract to the In-Shield position the TIP A Ball Valve was declared Inoperable due to not being able to close and meet its safety function in that configuration. Furthermore the TIP A Shear Valve was previously declared Inoperable due to the Firing Fuses being removed. With the two valves Inoperable the penetration could not be isolated and Primary Containment boundary isolation could not be established. TIP A was subsequently manually hand cranked and placed back into its In-Shield position at 1333 EDT restoring TIP A Ball Valve Operable. This report is being made pursuant to 10CFR50.72(b)(3)(v)(C) based on control the release of radioactive material. The Senior NRC Resident Inspector has been notified.
The purpose of this notification is to retract a previous report made on October 14, 2021 (EN 55522). At 1320 EDT on October 14, 2021 while performing Traversing In-Core Probe (TIP) Machine Gain Adjustment in support of Local Power Range Monitor (LPRM) calibration, an unplanned inoperability of the TIP 'A' Primary Containment Isolation Valve (PCIV) was reported pursuant to 10CFR50.72(b)(3)(v)(C) by EN 55522. On October 14, it was reported to the Main Control Room that TIP 'A' would not fully retract to the In-Shield position. With TIP 'A' unable to fully retract to the In-Shield position, the TIP 'A' Ball Valve PCIV was declared Inoperable due to not being able to close and meet its safety function in that configuration. The TIP 'A' Shear Valve PCIV was previously declared inoperable due to firing fuses being removed. Further investigation determined that a "FAULT: MOVEMENT LIMITED" error was received. This TIP error condition did not present a primary containment isolation issue in the event of a primary containment isolation signal. The Automatic TIP Control Unit (ATCU) is designed to command the TIP drive mechanism to continuously retract a TIP probe to the in-shield position in the event of a containment isolation signal with this condition. In the event of a containment isolation signal, the TIP machine would withdraw the TIP detector back to the in-shield position and the TIP A ball valve PCIV would have closed to perform its safety function. Therefore, the inoperability of TIP 'A' ball valve reported under criterion 10CFR50.72(b)(3)(v)(C) was not met, and EN 55522 is hereby retracted. The NRC Resident Inspector has been notified. Notified R3DO (Peterson) | Primary containment | |
| ENS 54567 | 5 March 2020 17:35:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Momentarily Inoperable | On March 05, 2020, at 1235 EST, with the reactor at 100 percent core thermal power and steady state conditions, plant personnel notified the main control room that both doors in the secondary containment airlock on the reactor building fifth floor were opened simultaneously for a period of approximately three seconds (i.e., from 12:35:00 to 12:35:03 EST). The failure of this interlock, which is intended to prevent both doors from being opened simultaneously, resulted in the Technical Specification (TS) Surveillance Requirement (SR) 3 .6.4.1.3 not being met. The maximum secondary containment pressure observed during that time remained within TS limits. There were no radiological releases associated with this event. Declaring secondary containment inoperable as a result of not meeting TS SR 3.6.4.1.3 is reportable under 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee has notified the NRC Resident Inspector. | Secondary containment | |
| ENS 54452 | 18 December 2019 14:08:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Pressure Degraded | On December 18, 2019, at 0908 EST, with the East and Center Reactor Building HVAC (RBHVAC) trains in service, secondary containment pressure degraded to the point where the Technical Specification (TS) requirement for secondary containment pressure was not met and secondary containment was declared inoperable. Secondary containment pressure did not meet the TS required limit for approximately four minutes. The maximum secondary containment pressure observed during that time was approximately 0.064 inches of vacuum water gauge. Secondary containment pressure was returned to within the TS operability limit of greater than or equal to 0.125 inches of vacuum water gauge (TS SR 3.6.4.1.1) by starting Division 1 of the Standby Gas Treatment System (SGTS). Secondary containment was declared Operable at 0912 EST. A modulating damper associated with the Center train of RBHVAC was identified as not properly controlling; an investigation is in progress. RBHVAC was manually secured to support problem identification and resolution. Secondary containment pressure is currently stable with Division 1 SGTS in service. There were no radiological releases associated with this event. Declaring secondary containment inoperable is reportable under 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The NRC Resident Inspector has been notified. | Secondary containment HVAC Standby Gas Treatment System | |
| ENS 54299 | 30 September 2019 02:28:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Pressure Exceeded Technical Specification Requirement | On September 29, 2019 at 2228 EDT, during a planned swap of Reactor Building HVAC trains, the exhaust fan discharge damper for the train being removed from service failed to close when the train was shutdown, which resulted in the Technical Specification (TS) for secondary containment pressure not being met for approximately 2 minutes and 15 seconds. The maximum secondary containment pressure observed during that time was approximately 0.1 inches of water gauge (positive). Secondary containment pressure was returned to within the TS operability limit of greater than or equal to 0.125 inches of vacuum water gauge (TS SR 3.6.4.1.1) by restarting the train of RBHVAC. Secondary containment pressure is currently stable. Secondary containment was declared Operable at 2235 EDT. There were no radiological releases associated with this event. Declaring secondary containment inoperable is reportable under 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The Licensee has notified the NRC Resident Inspector. | Secondary containment HVAC | |
| ENS 54094 | 30 May 2019 02:10:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Declared Inoperable | On May 29, 2019, at 2210 EDT, plant personnel notified the Main Control Room that both doors in the Secondary Containment Airlock on the Reactor Building First Floor were opened simultaneously for a period of approximately two seconds. This resulted in Technical Specification (TS) Surveillance Requirement (SR) 3.6.4.1.3 not being met. Secondary Containment pressure observed during that time remained unchanged and within TS limits. There were no radiological releases associated with this event. Declaring Secondary Containment inoperable as a result of not meeting TS SR 3.6.4.1.3 is reportable under 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee has notified the NRC Resident Inspector. | Secondary containment | |
| ENS 53883 | 19 February 2019 17:53:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Inoperable | On February 19, 2019, at 1307 EST, with the reactor at 100 percent Core Thermal Power and steady state conditions, plant personnel notified the Main Control Room that both doors in the Secondary Containment Airlock on the Reactor Building Fifth Floor were opened simultaneously for a period of approximately five minutes (i.e., from 1253 to 1258 EST). The failure of this interlock, which is intended to prevent both doors from being opened simultaneously, resulted in the Technical Specification (TS) Surveillance Requirement (SR) 3.6.4.1.3 not being met. The maximum Secondary Containment pressure observed during that time remained within TS limits. There were no radiological releases associated with this event. Declaring Secondary Containment inoperable as a result of not meeting TS SR 3.6.4.1.3 is reportable under 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee has notified the NRC Resident Inspector. The repair to the failed interlock is in progress. As a compensatory measure signs are posted on the doors to notify personnel to not access the Reactor Building via those doors. | Secondary containment | |
| ENS 53811 | 1 January 2019 05:00:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Gland Seal Exhauster - Automatic Trip Function Inoperable | On January 1, 2019 at approximately 0454 EST, while performing planned maintenance activities on the Feedwater Distributed Control System (FW DCS), it was discovered that the automatic trip instrumentation of the Gland Seal Exhauster (GSE) was inoperable. The automatic GSE trip is assumed in the safety analysis for the Control Rod Drop Accident (CRDA) and is required when Thermal Power is less than or equal to 10%. The automatic trip function of the GSE was inoperable for 1 minute, 19 seconds. No Control Rod movement occurred while the automatic trip of the GSE was inoperable. There was no adverse impact to public health and safety or to plant employees and there was no radiological release. This report is being made pursuant to 10CFR50.72(b)(3)(v)(C) and 10CFR50.72(b)(3)(v)(D). The NRC Resident Inspector has been notified. | Feedwater Control Rod | |
| ENS 53435 | 31 May 2018 18:20:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Reactor Water Cleanup System Declared Inoperable | On May 31, 2018 at 1420 EDT, the Reactor Water Cleanup (RWCU) System Isolation Differential Flow - High function was declared inoperable as a result of indicating downscale. This condition would have prevented the primary containment isolation valves for the RWCU system from automatically isolating on a high differential flow condition. At 1519 EDT, RWCU was shutdown and the affected penetration flow paths were isolated in accordance with station procedures per Fermi Technical Specifications. The cause of the event is under investigation. There was no radiological release associated with this event. All other RWCU primary containment isolation instrumentation functions remained operable and the associated RWCU system primary containment isolation valves were capable of being remotely closed by the control room operators throughout the event. However, the condition is reportable pursuant to 10 CFR 50.72(b)(3)(v)(C), and 10 CFR 50.72(b)(3)(v)(D). The NRC Resident Inspector was notified. | Primary containment Reactor Water Cleanup | |
| ENS 53429 | 27 May 2018 10:30:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Reactor Water Cleanup System Declared Inoperable | On May 27, 2018 at 0630 EDT, the Reactor Water Cleanup (RWCU) System Isolation Differential Flow - High function was declared inoperable as a result of indicating downscale. This condition would have prevented the primary containment isolation valves for the RWCU system from automatically isolating on a high differential flow instrumentation signal. At 0753, RWCU was shutdown and the affected penetration flow paths were isolated in accordance with station procedures per Fermi Technical Specifications. The cause of the event is under investigation. There was no radiological release associated with this event. All other RWCU primary containment isolation instrumentation functions remained operable and the associated RWCU system primary containment isolation valves were capable of being remotely closed by the control room operators throughout the event. However, the condition is reportable pursuant to 10 CFR 50.72(b)(3)(v)(C) and 10 CFR 50.72(b)(3)(v)(D). The NRC Resident Inspector was notified. | Primary containment Reactor Water Cleanup | |
| ENS 53165 | 11 January 2018 15:41:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Momentary Low Pressure | On January 11, 2018, at 1041 EST, a planned train swap of the Reactor Building Heating Ventilation and Air Conditioning (RBHVAC) system resulted in the Technical Specification (TS) for secondary containment pressure boundary not being met for less than one minute. The maximum secondary containment pressure observed during that time was approximately 0.117 inches of vacuum water gauge. Secondary containment pressure was returned to within the TS operability limit of greater than or equal to 0.125 inches of vacuum water gauge per TS Surveillance Requirement (SR) 3.6.4.1.1 by starting Division 1 of the Standby Gas Treatment System (SGTS) in addition to the RBHVAC system already in operation. Secondary containment pressure is currently stable. Secondary containment was declared Operable at 1045 EST. There were no radiological releases associated with this event. Declaring secondary containment inoperable as a result of not meeting TS SR 3.6.4.1.1 is reportable under 10CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee has notified the NRC Resident Inspector. | Secondary containment Standby Gas Treatment System | |
| ENS 52651 | 30 March 2017 21:10:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Technical Specification Not Met | On March 30, 2017 at 1710 EDT, with Reactor Building HVAC in service maintaining normal building pressure, Reactor Building pressure began to rise for an unknown reason. The Technical Specification (TS) for secondary containment pressure boundary was not met for approximately 50 seconds. Division 1 Standby Gas Treatment System was started and returned Secondary Containment pressure to the TS operability limit of 0.125 inches of vacuum water gauge (TS SR 3.6.4.1.1). The highest pressure observed on the Main Control Room indications was 0.105 inches of vacuum water gauge. During the event, Operations with the Potential to Drain the Reactor Vessel (OPDRV) were in progress. Actions to immediately suspend OPDRVs were taken. Investigation of the cause of the event is in progress. There were no radiological releases associated with this event. Declaring secondary containment inoperable is reportable under 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee has notified the NRC Resident Inspector.
The purpose of this notification is to retract a previous report made on March 30, 2017 (EN 52651). The notification to the NRC involved an event where secondary containment momentarily exceeded the Technical Specification (TS) requirements during refueling activities which had been designated as operations with the potential to drain the reactor vessel (OPDRVs). The notification was made under 10 CFR 50.72(b)(3)(v)(C) as an 'event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to ... control the release of radioactive material.' Subsequent to the initial notification, the event and the NRC guidance in NUREG-1022 pertaining to 10 CFR 50.72(b)(3)(v) were reviewed further. At the time of the event, Fermi 2 was shutdown (Mode 5. Refueling). In Mode 5, the pressures and temperatures that could cause a loss of coolant accident (LOCA) are not present. No movement of fuel was in progress such that the fuel handling accident (FHA) was also not applicable. Thus secondary containment was only required per TS 3.6.4.1 due to the ongoing OPDRVs. The Fermi 2 UFSAR does not describe OPDRVs as an accident that secondary containment is required to mitigate. Based on this information, secondary containment was not required to mitigate the consequences of an accident as described in the UFSAR during the event on March 30, 2017. Under these circumstances, the momentary exceedance of TS requirements for secondary containment is not considered a loss of safety function under 10 CFR 50.72(b)(3)(v) per the guidance in NUREG-1022. Therefore, EN 52651 is retracted and no Licensee Event Report (LER) under 10 CFR 50.73(a)(2)(v) is required to be submitted. The NRC Resident Inspector has been notified. Notified the R3DO (Cameron). | Secondary containment HVAC Standby Gas Treatment System | |
| ENS 52437 | 15 December 2016 15:10:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Momentary Low Pressure | On December 15, 2016, at 1010 EST, the startup of the Reactor Building HVAC (Heating Ventilation and Air Conditioning) system resulted in the Technical Specification (TS) for secondary containment pressure boundary not being met for approximately 1 second. The maximum secondary containment pressure observed during that time was approximately 0.044 inches of vacuum water gauge. Secondary containment pressure was returned to within the TS operability limit of 0.125 inches of vacuum water gauge (TS SR 3.6.4. 1.1) by Reactor Building HVAC and Standby Gas Treatment System already in operation. There were no radiological releases associated with this event. Declaring secondary containment inoperable is reportable under 10CFR50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee has notified the NRC Resident Inspector.
In this event notification, DTE Electric Company (DTE) reported conditions whereby the Fermi 2 secondary containment was believed to have exceeded Technical Specification Surveillance Requirements due to high winds. DTE hereby retracts this event notification as the Fermi 2 secondary containment has been determined to have been operable during this event as described below. The Fermi 2 secondary containment pressure is maintained at a pressure less than the external pressure to contain, dilute, hold up, and reduce the activity level of fission products prior to release to the environment, and to isolate and contain fission products that are released during a Design Basis Accident or certain operations. Secondary containment pressure is monitored by a number of differential pressure (dP) sensors. High wind gusts have resulted in momentary negative pressure on the leeward side of the building, causing a more positive pressure indication from one or more dP sensors. The secondary containment building pressure remains relatively constant during these 'wind events.' In December 2016, DTE implemented a software design change to display a 120-second rolling average for secondary containment dP indication. A 120-second rolling average recorded every second provides the operator a more accurate report of actual secondary containment conditions, while mitigating the signal noise and wind gust effects. The conditions associated with the subject event notification were re-reviewed in light of the improved secondary containment dP indication and it was determined that the Fermi 2 secondary containment was operable during this event. Specifically, the secondary containment pressure did not exceed Technical Specification Surveillance Requirements during this event. In summary, the above event notification is retracted because the Fermi 2 secondary containment was determined to have been fully operable during the conditions identified in the subject report. The licensee notified the NRC Resident Inspector. Notified R3DO (Stoedter). | Secondary containment HVAC Standby Gas Treatment System | |
| ENS 52434 | 15 December 2016 04:45:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Momentary Low Pressure Due to High Winds | On December 14, 2016, starting at 2345 EST, high wind conditions encountered on site resulted in the Technical Specification (TS) for secondary containment pressure boundary not being met numerous times. The duration of time that the secondary containment Technical Specification was not met was approximately one second for each instance. All plant equipment responded as required to the changing environmental conditions and Reactor Building HVAC returned secondary containment pressure within TS limits. At 0300 EST on December 15, 2016, high wind conditions had subsided and secondary containment vacuum was greater than the TS operability limit of 0.125 inches of vacuum water gauge (TS SR 3.6.4.1.1) and steady, and the LCO was exited. There were no radiological releases associated with this event. Declaring secondary containment inoperable is reportable under 10CFR50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee has notified the NRC Resident Inspector.
In this event notification, DTE Electric Company (DTE) reported conditions whereby the Fermi 2 secondary containment was believed to have exceeded Technical Specification Surveillance Requirements due to high winds. DTE hereby retracts this event notification as the Fermi 2 secondary containment has been determined to have been operable during this event as described below. The Fermi 2 secondary containment pressure is maintained at a pressure less than the external pressure to contain, dilute, hold up, and reduce the activity level of fission products prior to release to the environment, and to isolate and contain fission products that are released during a Design Basis Accident or certain operations. Secondary containment pressure is monitored by a number of differential pressure (dP) sensors. High wind gusts have resulted in momentary negative pressure on the leeward side of the building, causing a more positive pressure indication from one or more dP sensors. The secondary containment building pressure remains relatively constant during these 'wind events.' In December 2016, DTE implemented a software design change to display a 120-second rolling average for secondary containment dP indication. A 120-second rolling average recorded every second provides the operator a more accurate report of actual secondary containment conditions, while mitigating the signal noise and wind gust effects. The conditions associated with the subject event notification were re-reviewed in light of the improved secondary containment dP indication and it was determined that the Fermi 2 secondary containment was operable during this event. Specifically, the secondary containment pressure did not exceed Technical Specification Surveillance Requirements during this event. In summary, the above event notification is retracted because the Fermi 2 secondary containment was determined to have been fully operable during the conditions identified in the subject report. The licensee notified the NRC Resident Inspector. Notified R3DO (Stoedter) | Secondary containment HVAC | |
| ENS 52432 | 14 December 2016 05:00:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Pressure Boundary Out of Specification | On December 14, 2016, at 1314 EST, the startup of the Reactor Building HVAC (Heating, Ventilation and Air Conditioning) system resulted in the Technical Specification (TS) for secondary containment pressure boundary not being met for approximately 1 second. The maximum secondary containment pressure observed during that time was approximately 0.07 inches of vacuum water gauge. Secondary containment pressure was returned to within the TS operability limit of 0.125 inches of vacuum water gauge (TS SR 3.6.4.1.1) by Reactor Building HVAC and Standby Gas Treatment System already in operation. There were no radiological releases associated with this event. Declaring secondary containment inoperable is reportable under 10CFR50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee has notified the NRC Resident Inspector.
In this event notification, DTE Electric Company (DTE) reported conditions whereby the Fermi 2 secondary containment was believed to have exceeded Technical Specification Surveillance Requirements due to high winds. DTE hereby retracts this event notification as the Fermi 2 secondary containment has been determined to have been operable during this event as described below. The Fermi 2 secondary containment pressure is maintained at a pressure less than the external pressure to contain, dilute, hold up, and reduce the activity level of fission products prior to release to the environment, and to isolate and contain fission products that are released during a Design Basis Accident or certain operations. Secondary containment pressure is monitored by a number of differential pressure (dP) sensors. High wind gusts have resulted in momentary negative pressure on the leeward side of the building, causing a more positive pressure indication from one or more dP sensors. The secondary containment building pressure remains relatively constant during these 'wind events.' In December 2016, DTE implemented a software design change to display a 120-second rolling average for secondary containment dP indication. A 120-second rolling average recorded every second provides the operator a more accurate report of actual secondary containment conditions, while mitigating the signal noise and wind gust effects. The conditions associated with the subject event notification were re-reviewed in light of the improved secondary containment dP indication and it was determined that the Fermi 2 secondary containment was operable during this event. Specifically, the secondary containment pressure did not exceed Technical Specification Surveillance Requirements during this event. In summary, the above event notification is retracted because the Fermi 2 secondary containment was determined to have been fully operable during the conditions identified in the subject report. The licensee notified the NRC Resident Inspector. Notified R3DO (Stoedter) | Secondary containment HVAC Standby Gas Treatment System | |
| ENS 52398 | 29 November 2016 02:05:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Technical Specification Not Met | On November 28, 2016, starting at 2105 hrs. EST, high wind conditions encountered on site resulted in the Technical Specification (TS) for secondary containment pressure boundary not being met numerous times. The duration of time that the secondary containment Technical Specification was not met was approximately 1 second for each instance. All plant equipment responded as required to the changing environmental conditions and Reactor Building HVAC returned secondary containment pressure within TS limits. At 0055 EST on November 29, 2016, high wind conditions had subsided and secondary containment vacuum was greater than the TS operability limit of 0.125 inches of vacuum water gauge (TS SR 3.6.4.1.1) and steady, and the LCO was exited. There were no radiological releases associated with this event. Declaring secondary containment inoperable is reportable under 10CFR50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee has notified the NRC Resident Inspector.
On November 29, 2016, at 0242 EST, high wind conditions encountered on site resulted in the Technical Specification (TS) for secondary containment pressure boundary not being met numerous times following the initial event notification. The duration of time that the secondary containment Technical Specification was not met was approximately 1 second for each instance. All plant equipment responded as required to the changing environmental conditions and Reactor Building HVAC returned secondary containment pressure to within TS limits. High wind conditions are expected to decrease throughout the day. If additional instances are identified that require entry into the Technical Specifications (TS) for secondary containment pressure boundary not being met, another follow up notification will be performed. There were no radiological releases associated with this event. Declaring secondary containment inoperable is reportable under 10CFR50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee has notified the NRC Resident Inspector. Notified R3DO (Stoedter).
In this event notification, DTE Electric Company (DTE) reported conditions whereby the Fermi 2 secondary containment was believed to have exceeded Technical Specification Surveillance Requirements due to high winds. DTE hereby retracts this event notification as the Fermi 2 secondary containment has been determined to have been operable during this event as described below. The Fermi 2 secondary containment pressure is maintained at a pressure less than the external pressure to contain, dilute, hold up, and reduce the activity level of fission products prior to release to the environment, and to isolate and contain fission products that are released during a Design Basis Accident or certain operations. Secondary containment pressure is monitored by a number of differential pressure (dP) sensors. High wind gusts have resulted in momentary negative pressure on the leeward side of the building, causing a more positive pressure indication from one or more dP sensors. The secondary containment building pressure remains relatively constant during these 'wind events.' In December 2016, DTE implemented a software design change to display a 120-second rolling average for secondary containment dP indication. A 120-second rolling average recorded every second provides the operator a more accurate report of actual secondary containment conditions, while mitigating the signal noise and wind gust effects. The conditions associated with the subject event notification were re-reviewed in light of the improved secondary containment dP indication and it was determined that the Fermi 2 secondary containment was operable during this event. Specifically, the secondary containment pressure did not exceed Technical Specification Surveillance Requirements during this event. In summary, the above event notification is retracted because the Fermi 2 secondary containment was determined to have been fully operable during the conditions identified in the subject report. The licensee notified the NRC Resident Inspector. Notified R3DO (Stoedter). | Secondary containment HVAC | |
| ENS 52380 | 20 November 2016 02:50:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Technical Specification Not Met | On November 19, 2016, starting at 2150 EST, high wind conditions encountered on site resulted in the Technical Specification (TS) for secondary containment pressure boundary not being met numerous times. The duration of time that the secondary containment Technical Specification was not met was approximately 1 second for each instance. All plant equipment responded as required to the changing environmental conditions and Reactor Building HVAC returned secondary containment pressure within TS limits. At 0430 EST, high wind conditions have subsided and secondary containment vacuum was greater than the TS operability limit of 0.125 inches of vacuum water gauge (TS SR 3.6.4.1.1) and steady, and the LCO was exited. There were no radiological releases associated with this event. Declaring secondary containment inoperable is reportable under 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee has notified the NRC Resident Inspector.
On November 20, 2016, starting at 0654 EST, high wind conditions encountered on site resulted in the Technical Specification (TS) for secondary containment pressure boundary not being met on multiple different occasions as of event notification update time. The duration of time that the secondary containment Technical Specification was not met was approximately 1 second for each instance. Fermi 2 continues to remain in a gale force wind advisory for the local area of Lake Erie. All plant equipment responded as required to the changing environmental conditions and Reactor Building HVAC returned secondary containment pressure within TS limits. There were no radiological releases associated with this event. Declaring secondary containment inoperable is reportable under 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee has notified the NRC Resident Inspector. The R3DO (Jeffers) has been notified.
On November 20, 2016, at 1426 EST, high wind conditions encountered on site resulted in the Technical Specification (TS) for secondary containment pressure boundary not being met. The duration of time that the secondary containment Technical Specification was not met was approximately 1 second. The Fermi 2 local area of Lake Erie is no longer in a gale force wind advisory and the high wind conditions have subsided. All plant equipment responded as required to the changing environmental conditions and Reactor Building HVAC returned secondary containment pressure within TS limits. There were no radiological releases associated with this event. Declaring secondary containment inoperable is reportable under 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee has notified the NRC Resident Inspector. The R3DO (Jeffers) has been notified.
In this event notification, DTE Electric Company (DTE) reported conditions whereby the Fermi 2 secondary containment was believed to have exceeded Technical Specification Surveillance Requirements due to high winds. DTE hereby retracts this event notification as the Fermi 2 secondary containment has been determined to have been operable during this event as described below. The Fermi 2 secondary containment pressure is maintained at a pressure less than the external pressure to contain, dilute, hold up, and reduce the activity level of fission products prior to release to the environment, and to isolate and contain fission products that are released during a Design Basis Accident or certain operations. Secondary containment pressure is monitored by a number of differential pressure (dP) sensors. High wind gusts have resulted in momentary negative pressure on the leeward side of the building, causing a more positive pressure indication from one or more dP sensors. The secondary containment building pressure remains relatively constant during these 'wind events.' In December 2016, DTE implemented a software design change to display a 120-second rolling average for secondary containment dP indication. A 120-second rolling average recorded every second provides the operator a more accurate report of actual secondary containment conditions, while mitigating the signal noise and wind gust effects. The conditions associated with the subject event notification were re-reviewed in light of the improved secondary containment dP indication and it was determined that the Fermi 2 secondary containment was operable during this event. Specifically, the secondary containment pressure did not exceed Technical Specification Surveillance Requirements during this event. In summary, the above event notification is retracted because the Fermi 2 secondary containment was determined to have been fully operable during the conditions identified in the subject report. The licensee notified the NRC Resident Inspector. Notified R3DO (Stoedter) | Secondary containment HVAC | |
| ENS 52331 | 28 October 2016 19:00:00 | 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Standby Liquid Control Technical Specification Not Met | On October 28, 2016, at 1500 EDT, the Standby Liquid Control system was declared inoperable. Technical Specification (TS) Limiting Condition for Operation (LCO) 3.1.7 Condition B was entered due to sodium pentaborate concentration not within limits. Standby Liquid Control sodium pentaborate concentration was found to be low outside of the acceptable region following a Standby Liquid Control system tank high level alarm in the Main Control Room. Sodium pentaborate was added to the Standby Liquid Control tank by chemistry personnel and the concentration was then verified to be acceptable. Standby Liquid Control was declared Operable on 10/28/16 at 1935 EDT. The cause of the out-of-acceptable concentration was due to make-up water leaking by a closed valve. (The licensee cycled this valve and closed an upstream valve.) Declaring the Standby Liquid Control system inoperable is reportable under 10 CFR 50.72(b)(3)(v)(A), (C), and (D) as an event or condition that could have prevented the fulfillment of a safety function of a system needed to shut down the reactor and maintain it in a safe shutdown condition, control the release of radioactive material, and mitigate the consequences of an accident. The licensee has notified the NRC Resident Inspector. | Standby Liquid Control | |
| ENS 52320 | 27 October 2016 03:00:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Technical Specification Not Met | On October 26, 2016, at 2300 EDT, high wind conditions encountered on site resulted in the Technical Specification (TS) for secondary containment pressure boundary not being met numerous times. The duration of time that the secondary containment Technical Specification was not met was approximately one second for each instance. All plant equipment responded as required to the changing environmental conditions and Reactor Building HVAC returned secondary containment pressure within TS limits. At 2300 EDT, secondary containment vacuum was greater than the TS operability limit of 0.125 inches of vacuum water gauge (TS SR 3.6.4.1.1) and steady, and the LCO was exited. There were no radiological releases associated with this event. A review indicates that this condition occurred earlier this shift during the high wind condition. Declaring secondary containment inoperable is reportable under 10CFR50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee has notified the NRC Resident Inspector .
In this event notification, DTE Electric Company (DTE) reported conditions whereby the Fermi 2 secondary containment was believed to have exceeded Technical Specification Surveillance Requirements due to high winds. DTE hereby retracts this event notification as the Fermi 2 secondary containment has been determined to have been operable during this event as described below. The Fermi 2 secondary containment pressure is maintained at a pressure less than the external pressure to contain, dilute, hold up, and reduce the activity level of fission products prior to release to the environment, and to isolate and contain fission products that are released during a Design Basis Accident or certain operations. Secondary containment pressure is monitored by a number of differential pressure (dP) sensors. High wind gusts have resulted in momentary negative pressure on the leeward side of the building, causing a more positive pressure indication from one or more dP sensors. The secondary containment building pressure remains relatively constant during these 'wind events.' In December 2016, DTE implemented a software design change to display a 120-second rolling average for secondary containment dP indication. A 120-second rolling average recorded every second provides the operator a more accurate report of actual secondary containment conditions, while mitigating the signal noise and wind gust effects. The conditions associated with the subject event notification were re-reviewed in light of the improved secondary containment dP indication and it was determined that the Fermi 2 secondary containment was operable during this event. Specifically, the secondary containment pressure did not exceed Technical Specification Surveillance Requirements during this event. In summary, the above event notification is retracted because the Fermi 2 secondary containment was determined to have been fully operable during the conditions identified in the subject report. The licensee notified the NRC Resident Inspector. Notified R3DO (Stoedter). | Secondary containment HVAC | |
| ENS 52205 | 27 August 2016 19:00:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Technical Specification Not Met | On August 27, 2016, at 1500 EDT a severe thunderstorm occurred in Monroe County, including the Fermi 2 site. Due to high winds encountered during the thunderstorm, the Technical Specification (TS) for secondary containment pressure boundary was not met numerous times. The duration of time that the secondary containment Technical Specification was not met was approximately 1 second for each event. All plant equipment responded as required to the changing environmental conditions and Reactor Building HVAC returned secondary containment pressure within TS limits. At 1540 EDT, secondary containment vacuum was greater than the TS operability limit of 0.125 inches of vacuum water gauge (TS SR 3.6.4.1.1) and steady, and the LCO was exited. There were no radiological releases associated with this event. Declaring secondary containment inoperable is reportable under 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee has notified the NRC Resident Inspector.
In this event notification, DTE Electric Company (DTE) reported conditions whereby the Fermi 2 secondary containment was believed to have exceeded Technical Specification Surveillance Requirements due to high winds. DTE hereby retracts this event notification as the Fermi 2 secondary containment has been determined to have been operable during this event as described below. The Fermi 2 secondary containment pressure is maintained at a pressure less than the external pressure to contain, dilute, hold up, and reduce the activity level of fission products prior to release to the environment, and to isolate and contain fission products that are released during a Design Basis Accident or certain operations. Secondary containment pressure is monitored by a number of differential pressure (dP) sensors. High wind gusts have resulted in momentary negative pressure on the leeward side of the building, causing a more positive pressure indication from one or more dP sensors. The secondary containment building pressure remains relatively constant during these 'wind events.' In December 2016, DTE implemented a software design change to display a 120-second rolling average for secondary containment dP indication. A 120-second rolling average recorded every second provides the operator a more accurate report of actual secondary containment conditions, while mitigating the signal noise and wind gust effects. The conditions associated with the subject event notification were re-reviewed in light of the improved secondary containment dP indication and it was determined that the Fermi 2 secondary containment was operable during this event. Specifically, the secondary containment pressure did not exceed Technical Specification Surveillance Requirements during this event. In summary, the above event notification is retracted because the Fermi 2 secondary containment was determined to have been fully operable during the conditions identified in the subject report. The licensee notified the NRC Resident Inspector. Notified R3DO (Stoedter). | Secondary containment HVAC | |
| ENS 52146 | 2 August 2016 14:15:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Technical Specification Not Met | On August 2, 2016 at 1015 EDT, while restoring the east train of Reactor Building HVAC (RBHVAC) after a surveillance test on Division 2 Standby Gas Treatment System (SGTS), the Technical Specification (TS) for the secondary containment pressure boundary was not met for a duration time of approximately 1 second. The maximum secondary containment pressure observed during that time was approximately 0.120 inches of vacuum water gauge. Secondary containment pressure was returned to within the TS operability limit by RBHVAC and SGTS already in operation. There were no radiological releases associated with this event. The cause of the event is under investigation. The TS requirement is to maintain secondary containment vacuum greater than or equal to 0.125 inches of vacuum water gauge (TS SR 3.6.4.1.1) for secondary containment operability. Declaring secondary containment inoperable is reportable under 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee has notified the NRC Resident lnspector. | Secondary containment HVAC Standby Gas Treatment System | |
| ENS 52084 | 13 July 2016 23:55:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Technical Specification Not Met | On July 13, 2016, at 19:50 EDT a severe thunderstorm warning was issued for Monroe County. This severe thunderstorm warning included the Fermi 2 site. Due to high winds encountered during the thunderstorm, the Technical Specification (TS) for secondary containment pressure boundary was not met numerous times. The duration of time that the secondary containment Technical Specification was not met was approximately 1 second for each event. All plant equipment responded as required to the changing environmental conditions and Reactor Building HVAC returned secondary containment pressure within TS limits. At 20:40 EDT secondary containment vacuum was greater than the TS operability limit of 0.125 inches of vacuum water gauge (TS SR 3.6.4.1.1) and steady, and the LCO was exited. There were no radiological releases associated with this event. Declaring secondary containment inoperable is reportable under 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee has notified the NRC Resident Inspector.
In this event notification, DTE Electric Company (DTE) reported conditions whereby the Fermi 2 secondary containment was believed to have exceeded Technical Specification Surveillance Requirements due to high winds. DTE hereby retracts this event notification as the Fermi 2 secondary containment has been determined to have been operable during this event as described below. The Fermi 2 secondary containment pressure is maintained at a pressure less than the external pressure to contain, dilute, hold up, and reduce the activity level of fission products prior to release to the environment, and to isolate and contain fission products that are released during a Design Basis Accident or certain operations. Secondary containment pressure is monitored by a number of differential pressure (dP) sensors. High wind gusts have resulted in momentary negative pressure on the leeward side of the building, causing a more positive pressure indication from one or more dP sensors. The secondary containment building pressure remains relatively constant during these 'wind events.' In December 2016, DTE implemented a software design change to display a 120-second rolling average for secondary containment dP indication. A 120-second rolling average recorded every second provides the operator a more accurate report of actual secondary containment conditions, while mitigating the signal noise and wind gust effects. The conditions associated with the subject event notification were re-reviewed in light of the improved secondary containment dP indication and it was determined that the Fermi 2 secondary containment was operable during this event. Specifically, the secondary containment pressure did not exceed Technical Specification Surveillance Requirements during this event. In summary, the above event notification is retracted because the Fermi 2 secondary containment was determined to have been fully operable during the conditions identified in the subject report. The licensee notified the NRC Resident Inspector. Notified R3DO (Stoedter) | Secondary containment HVAC | |
| ENS 52076 | 9 July 2016 00:05:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Technical Specification Not Met | On July 8 2016, at 19:09 (EDT) a severe thunderstorm warning was issued for Monroe County. This severe thunderstorm warning included the Fermi 2 site. Due to the high winds encountered during the thunderstorm, the Technical Specification (TS) for the secondary containment pressure boundary was not met two times during the storm for a duration time of 2 seconds total (one second for each event). At 20:05:21 Secondary Containment pressure went positive (0.22 inches of water gauge) and at 20:05:22 returned back below plant TS limits (-0.35 inches of water gauge). At 20:06:33 Secondary Containment pressure went greater than TS limits (-0.10 inches of water gauge) and at 20:06:34 returned below TS limits (-0.28 inches of water gauge). All plant equipment responded as required to the changing environmental conditions and Reactor Building HVAC returned the secondary containment pressure below the TS limits. There were no radiological releases associated with this event. The severe thunderstorm warning for the area was cancelled at 20:30. The TS requirement is to maintain secondary containment greater than or equal to 0.125 inches of vacuum water gauge (TS SR 3.6.4.1.1) for secondary containment operability. Declaring secondary containment inoperable is reportable under 10 CFR 50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee has notified the NRC Resident Inspector.
In this event notification, DTE Electric Company (DTE) reported conditions whereby the Fermi 2 secondary containment was believed to have exceeded Technical Specification Surveillance Requirements due to high winds. DTE hereby retracts this event notification as the Fermi 2 secondary containment has been determined to have been operable during this event as described below. The Fermi 2 secondary containment pressure is maintained at a pressure less than the external pressure to contain, dilute, hold up, and reduce the activity level of fission products prior to release to the environment, and to isolate and contain fission products that are released during a Design Basis Accident or certain operations. Secondary containment pressure is monitored by a number of differential pressure (dP) sensors. High wind gusts have resulted in momentary negative pressure on the leeward side of the building, causing a more positive pressure indication from one or more dP sensors. The secondary containment building pressure remains relatively constant during these 'wind events.' In December 2016, DTE implemented a software design change to display a 120-second rolling average for secondary containment dP indication. A 120-second rolling average recorded every second provides the operator a more accurate report of actual secondary containment conditions, while mitigating the signal noise and wind gust effects. The conditions associated with the subject event notification were re-reviewed in light of the improved secondary containment dP indication and it was determined that the Fermi 2 secondary containment was operable during this event. Specifically, the secondary containment pressure did not exceed Technical Specification Surveillance Requirements during this event. In summary, the above event notification is retracted because the Fermi 2 secondary containment was determined to have been fully operable during the conditions identified in the subject report. The licensee notified the NRC Resident Inspector. Notified R3DO (Stoedter). | Secondary containment HVAC | |
| ENS 51449 | 4 October 2015 13:56:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Inoperable with the Potential to Drain the Reactor Vessel | On October 4th, at approximately 0956 EDT, 'Operations with the Potential to Drain the Reactor Pressure Vessel' (OPDRV) was unintentionally initiated without secondary containment operable. Operators promptly identified the condition and immediately initiated actions to identify and suspend the source of the drain path. At approximately 1120 EDT the source of the OPDRV was isolated. Reactor cavity water level and spent fuel pool level remained constant throughout the event. An investigation is in progress. The NRC Resident Inspector has been notified. | Secondary containment Reactor Pressure Vessel | |
| ENS 51391 | 14 September 2015 03:05:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Manual Scram Due to Loss of Turbine Building Closed Cooling Water | At 2305 EDT on September 13, 2015, a manual scram was initiated in response to a loss of all Turbine Building Closed Cooling Water (TBCCW). All control rods fully inserted. The lowest Reactor Water Level (RWL) reached was 137 inches. All isolations and actuations for RWL 3 occurred as expected. Decay heat was initially being removed through the Main Turbine Bypass System to the Main Condenser, however, as a result of the loss of TBCCW, the Main Feed Pumps lost cooling and had to be secured. At 2310, Standby Feedwater was initiated and Main Feedwater was secured. The loss of TBCCW also caused all Station Air Compressors (SACs) to trip on loss of cooling. The loss of SACs caused the Instrument Air header pressure to degrade to the point at which the Secondary Containment isolation dampers drifted closed. This resulted in the Reactor Building vacuum exceeding the Technical Specification limit. At 2325, operators started the Standby Gas Treatment system and manually initiated a Secondary Containment isolation signal. Secondary Containment vacuum was promptly restored to within Technical Specification limits. Additionally, Operators were monitoring for expected MSIV drift due to the degraded Instrument Air header pressure. When outboard MSIVs were observed to be drifting, Operators closed the outboard and inboard MSIVs at 2345. At 2352, Safety Relief Valves (SRVs) reached the Low-Low Setpoint and began cycling to control reactor pressure. RWL is currently being maintained in the normal level band with the Standby Feedwater and Control Rod Drive systems. Reactor Pressure is being controlled with Safety Relief Valves. Operators are currently in the Emergency Operating Procedure for Reactor Pressure Vessel control. Investigation into the loss of TBCCW continues. No safety-related equipment was out of service at the time of the event. All offsite power sources were adequate and available throughout the duration of the event. The NRC resident inspector has been notified.
At 0409 EDT the Reactor Core Isolation Cooling (RCIC) system was placed in service due to identification of an unisolable leak in the Standby Feedwater System. Reactor water level and pressure is now being controlled though the RCIC system and Safety Relief Valves. This event update is reportable as a valid manual initiation of a specified safety system under 10CFR50.72(b)(3)(iv)(A). The NRC resident inspector has been notified. The leak rate was reported as approximately 5-10 gallons per minute from a weld on the standby feedwater pump header drain valve F326. The licensee reported the leak stopped once RCIC was placed into service. The licensee is still investigating the issue. Notified the R3DO (Pelke), IRD Manager (Grant), NRR EO (Morris).
At 1847 EDT on September 14, 2015, a valid automatic Reactor Protection System (RPS) actuation occurred due to Reactor Water Level 3 while shutdown in MODE 3. Operators were manually controlling Reactor Pressure Vessel (RPV) level and pressure with Reactor Core Isolation Cooling (RCIC) and Safety Relief Valves (SRV). While operators were cycling SRVs, the RPV level went below the Level 3 setpoint. Operators promptly restored RPV level by manual operation of RCIC. The Level 3 actuation and associated isolations were verified to operate properly. The scram signal has been reset. Fermi 2 remains in MODE 3 controlling RPV Level and Pressure through manual operation of RCIC and SRVs. This is the second occurrence of a valid specified safety system actuation reportable under 10CFR50.72(b)(3)(iv)(A) for this ongoing event. The NRC Resident Inspector has been notified. Notified R3DO (Riemer), IRD Manager (Grant), and NRR EO (Morris)
This update provides clarification of the applicable reporting criteria for this Event associated with primary containment isolation actuations. Upon the manual reactor scram at 2305 EDT on September 13, 2015, Reactor Protection System (RPS) Level 3 actuated and Primary Containment Isolation System (PCIS) Groups 4, 13 and 15 actuated as expected. The applicable reporting criterion for these actuations is 10 CFR 50.72(b)(3)(iv)(A). The applicable reporting criterion for the manual closure of the inboard and outboard main steam isolation valves at 2345 EDT on September 13, 2015, is also 10 CFR 50.72(b)(3)(iv)(A). In addition, the manual closures of all MSIV lead to a loss of condenser vacuum which resulted in the actuation of PCIS Group 1 at 0001 EDT on September 14, 2015, as expected. The applicable reporting criterion for this actuation is also 10 CFR 50.72(b)(3)(iv)(A). Upon reaching Level 3 at 1847 EDT on September 14, 2015, PCIS Groups 4, 13 and 15 actuated as expected. The applicable reporting criterion for this actuation is 10 CFR 50.72(b)(3)(iv)(A). The licensee informed the NRC Resident Inspector. Notified the R3DO (Stone). | Feedwater Secondary containment Reactor Protection System Main Steam Isolation Valve Primary Containment Isolation System Reactor Core Isolation Cooling Primary containment Main Turbine Reactor Pressure Vessel Standby Gas Treatment System Safety Relief Valve Main Condenser Control Rod | |
| ENS 51313 | 12 August 2015 14:07:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Technical Specifications Not Met | At 1007 (EDT) on August 12, 2015, while restoring Reactor Building (RB) HVAC (RBHVAC) after surveillance testing, an equipment malfunction resulted in improper damper alignment resulting in Secondary Containment Technical Specifications (TS) to not be met. The plant TS require Secondary Containment pressure be maintained greater than or equal to -0.125 inches of vacuum water gauge (TS SR 3.6.4.1.1). This specification was not maintained for five seconds and the highest pressure observed was -0.095 inches of vacuum water gauge. This value was observed on only one of two installed recorders, of the Secondary Containment pressure recorders. The highest observed pressure on the other recorder was -0.14 inches of vacuum water gauge. Secondary Containment was restored by the Standby Gas Treatment System (SGTS) already in operation and shutting down the affected train of RBHVAC. The technical specification requirement is to maintain secondary containment at -0.125 inches of vacuum water gauge for secondary containment operability. Declaring secondary containment inoperable is reportable under 10 CFR50.72(b)(3)(v)(c) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee notified the NRC Resident Inspector.
The licensee is updating this report to delete the minus sign for all references to inches of vacuum water gauge. FOLLOW UP - CORRECTED INFORMATION: At 1007 (EDT) on August 12, 2015, while restoring Reactor Building (RB) HVAC (RBHVAC) after surveillance testing, an equipment malfunction resulted in improper damper alignment resulting in Secondary Containment Technical Specifications (TS) to not be met. The plant TS require Secondary Containment pressure be maintained greater than or equal to .125 inches of vacuum water gauge (TS SR 3.6.4.1.1). This specification was not maintained for five seconds and the highest pressure observed was .095 inches of vacuum water gauge. This value was observed on only one, of two installed recorders, of the Secondary Containment pressure recorders. The highest observed pressure on the other recorder was .14 inches of vacuum water gauge. Secondary Containment was restored by the Standby Gas Treatment System (SGTS) already in operation and shutting down the affected train of RBHV AC. The technical specification requirement is to maintain secondary containment greater than or equal to .125 inches of vacuum water gauge for secondary containment operability. Declaring secondary containment inoperable is reportable under 10CFR50.72(b)(3)(v)c as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. the licensee informed the NRC Resident Inspector. Notified R1DO (Powell). | Secondary containment HVAC Standby Gas Treatment System | |
| ENS 51202 | 7 July 2015 18:35:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Pressure Boundary Vacuum Not Maintained within Specifications | On 7/7/2015 at approximately 1435 EDT, the Technical Specification for Secondary Containment Pressure Boundary was not met when vacuum could not be maintained greater than or equal to -0.125 inches of water gauge for approximately 41 seconds. As part of post-maintenance testing for the non-safety related Reactor Building HVAC Center Exhaust Fan, the fan was started while the safety-related Standby Gas Treatment system was also in operation. Shortly after the fan was started, operators observed degrading vacuum in secondary containment and subsequently secured the center exhaust and supply fans. Vacuum continued to degrade momentarily after the fans were secured, and then returned to a Technical Specification allowable value. Subsequent inspections discovered that the affected fan was operating in the reverse direction. This is believed to have caused Secondary Containment pressure to increase. Since vacuum could not be maintained with the safety-related Standby Gas Treatment system operating, the plant operated in an unanalyzed condition. The cause of the reverse rotation is under investigation. There were no radiological releases associated with this event. The NRC Senior Resident Inspector has been notified.
Based on plant configuration at the time of the event and further review of the Fermi 2 UFSAR, the plant did not operate in an unanalyzed condition. The Reactor Building HVAC fans would have tripped, as designed, upon receipt of a safety-related Standby Gas Treatment actuation signal during the time of the event. Therefore, the fans' pressurizing effect on secondary containment would have ceased within the time limits assumed in the existing accident analysis. The reporting criteria of 10CFR50.72(b)(3)(v)(C) remains valid. The licensee notified the NRC Resident Inspector. Notified the R3DO (Stone). | Secondary containment HVAC Standby Gas Treatment System | |
| ENS 50831 | 19 February 2015 08:04:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Building Declared Inoperable Due to Ventilation System Trip | At 0304 EST on February 19, 2015, Fermi 2 experienced a trip of the Reactor Building Ventilation (RB) (HVAC) during plant operations associated with very cold temperatures outside. At the time of the trip, outside air temperature was -1 degrees Fahrenheit and RB HVAC tripped due to a Freeze-Stat actuation (a freeze protection feature). The plant Technical Specifications require that Secondary Containment pressure be maintained greater than or equal to -0.125 inches of vacuum water gauge (TS SR 3.6.4.1.1). This specification was not maintained and the highest pressure observed was -0.11 inches of vacuum water gauge. Subsequently, at 0450, during restoration activities, RB pressure degraded again to higher than -0.125 inches of vacuum water gauge for 38 seconds. The lowest observed pressure was -0.11 inches of vacuum water gauge. RB HVAC has been restored by resetting the Freeze-Stat and the Standby Gas Treatment System (SGTS) has been placed back in a standby condition. The technical specification requirement is to maintain secondary containment at -0.125 inches of vacuum water gauge for secondary containment operability. Declaring secondary containment inoperable is reportable under 10CFR50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee has notified the NRC Resident Inspector.
After reviewing the events that occurred on February 19, 2015 against the accident analyses in Chapter 15 of the UFSAR and design functions of the Standby Gas Treatment System and Secondary Containment structure, it is concluded that a condition that could have prevented the fulfillment of a safety function to control the release of radioactive material did not occur as a result of momentarily exceeding the Technical Specification for Secondary Containment vacuum after a loss of the normal Reactor Building Ventilation System. The Fermi 2 accident analysis for a LOCA does not assume that secondary containment is under vacuum throughout the duration of an accident and contains conservative leakage assumptions to bound the effects of a postulated ground level release. The accident analysis credits the operation of the Standby Gas Treatment System (SGTS); both divisions of SGTS were operable at the time of the event. Although secondary containment was declared inoperable due to exceeding the Technical Specification value for secondary containment vacuum, the structural integrity of the secondary containment was not degraded at the time. Upon receipt of an accident signal, SGTS would have automatically started and restored secondary containment vacuum to within the bounding analyses of Chapter 15 of the UFSAR. Secondary containment was capable of performing its design function of minimizing any ground level release of radioactive material by maintaining boundary integrity so that the SGTS may draw a vacuum in the Reactor Building and filter radioactive material at all times. The event reported in EN # 50831 did not result in a condition that could have prevented the fulfillment of a safety function to control the release of radioactive material. This event report is being retracted. The licensee informed the NRC Resident Inspector. Notified R3DO (Skokowski).
Upon further review of NUREG-1022 section 3.2.7, the original Non-Emergency Event Notification, 50831, remains valid. The NRC Resident Inspect has been informed. Notified R3DO (McCraw). | Secondary containment HVAC Reactor Building Ventilation Standby Gas Treatment System | |
| ENS 49575 | 24 November 2013 05:01:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Momentary Loss of Reactor Building Ventilation | On 11/24/2013 at 00:00:54 seconds (EST), Reactor Building ventilation tripped due to low outside air temperature. At 00:01:42 seconds, Secondary Containment Differential pressure went positive, with a maximum of +0.08 inches WC (water column). This is a loss of Secondary Containment function. At 00:02:30 seconds, Standby Gas Treatment System was started and Secondary Containment pressure then decreased to <0 inches WC at 00:03:18 seconds. All the above data parameters were taken from the Division 2 Reactor Building Differential pressure recorder. Secondary Containment pressure is stable with differential pressure negative <-0.30 inches WC. The loss of Secondary Containment function is reportable under 10CFR 50.72(b)(3)(v)(c) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. Technical Specification requirement are to maintain secondary containment pressure <-0.125 WC. No actual radiation release occurred during the event. The licensee notified the NRC Resident Inspector. | Secondary containment Reactor Building Ventilation Standby Gas Treatment System | |
| ENS 48689 | 22 January 2013 06:13:00 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Secondary Containment Pressure Positive for 12 Seconds | On 01/22/2013 at 00:30 Reactor building HVAC tripped due to low outside air temperature and Standby Gas Treatment system was manually started and maintained Reactor Building differential pressure negative. At 01:13 secondary containment pressure went positive during restart of the Center Reactor Building HVAC Train. This is a loss of secondary containment function. In a 12 second time span secondary containment pressure went above 0 inches WC (Water Column) to +0.17 inches WC and then decreased to < 0 inches WC remaining stable during the Reactor Building HVAC restart. The Center Reactor Building HVAC Exhaust Fan Discharge Damper opened after the Supply Fan discharge damper; this condition would produce the indications noted. The System was returned to normal with two Reactor Building HVAC trains running and the Standby Gas Treatment System shutdown and in standby. Reactor building pressure is stable with differential pressure negative < - 0.30 inches WC. The loss of Secondary Containment function is reportable under 10 CFR 50.72 (b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The licensee notified the NRC Resident Inspector. | Secondary containment HVAC Standby Gas Treatment System | |
| ENS 42783 | 17 August 2006 23:00:00 | 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | Emergency Diesel Generators Inoperable Due to Undersized Breaker Control Transformers | At 1900 hrs on 8/17/06, all four Emergency Diesel Generators (EDGs) were declared INOPERABLE. The inoperability is a result of undersized control transformers for each of the Emergency Diesel Generator Service Water (DGSW) Pumps. The concern is that the DGSW pump contactors will not receive adequate voltage at the starters to ensure the starters pickup under degraded voltage conditions. A 2 hour Limiting Condition for Operability (LCO) was entered per LCO 3.8.1 to restore both EDGs in one division to OPERABLE status. At 2100 hours on 8/17/06 the two hour time requirement expired and a 12 hour LCO to place the plant in Mode 3 (Hot Shutdown) was entered. At 0042 hrs on 8/18/06, compensatory measures have been put in place to restore operability to both division 2 EDGs. The compensatory measures include placing the local control switch for both division 2 DGSW Pumps in run. Placing the local control switches in run ensures sufficient voltage will be available at the starters to ensure the starters pickup following a loss of offsite power, load shed, and restoration of power to the applicable busses. With operability restored to division 2 EDGs, the new expiration time for the LCO has been revised to 72 hours based on discovery of one or both EDGs in one division inoperable concurrent with CTG 11-1 (station blackout Combustion Turbine Generator 11-1) not available. After 72 hours, if operability is not restored to either CTG 11-1 or both division 1 EDGs, the plant will be required to enter Mode 3 within the following 12 hours. This report is being made pursuant to 10CFR50.72.(b)(3)(v) as an 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 (A) Shut down the reactor and maintain it in a safe shutdown condition; (B) Remove Residual Heat; (C) Control the release of radioactive material; or (D) Mitigate the consequences of an accident. The NRC resident inspector has been notified. The licensee stated that the current 72 hour LCO will expire at 1900 EDT 08/20/06. | Service water Emergency Diesel Generator | 05000341/LER-2006-004 |