ENS 52651
ENS Event | |
|---|---|
21:10 Mar 30, 2017 | |
| Title | Secondary Containment Technical Specification Not Met |
| Event Description | 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). |
| Where | |
|---|---|
Fermi  Michigan (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | |
| Time - Person (Reporting Time:+-1.08 h-0.045 days <br />-0.00643 weeks <br />-0.00148 months <br />) | |
| Opened: | Jeff Yeager 20:05 Mar 30, 2017 |
| NRC Officer: | Donald Norwood |
| Last Updated: | May 15, 2017 |
| 52651 - NRC Website | |