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| Entered date | Event description | |
|---|---|---|
| ENS 52830 | 27 June 2017 01:05:00 | On June 26, 2017 at 1756 PDT, Reactor Building (Secondary Containment) pressure rose above the Technical Specification (TS) requirement multiple times from 1756 to 1800. Secondary Containment was declared inoperable and entry into Technical Specification Action Statement 3.6.4.1.A was made. There was a significant change in average wind speed and barometric pressure occurring at that time. At 1800 PDT, Secondary Containment pressure was restored to within limits and TS 3.6.4.1.A was exited. Environmental conditions have stabilized. The Reactor Building Differential Pressure controllers are working as designed. This condition is being reported under 10 CFR 50.72(b)(3)(v)(C) and 10 CFR 50.72(b)(3)(v)(D) for an event or condition that could have prevented fulfillment of a safety function needed to control the release of radioactive material and accident mitigation. The licensee has notified the NRC Resident Inspector. |
| ENS 52848 | 11 July 2017 17:45:00 | This report is being made pursuant to 10 CFR 50.72(b)(3)(v)(D) as an event or condition that could have prevented fulfillment of a safety function. On July 11th, 2017, it was discovered that the flow indicating switch for the high pressure core spray (HPCS) minimum flow valve was providing unreliable indication. There was no flow through the line at the time the condition was discovered. This switch provides the flow signal to the HPCS minimum flow valve logic. The switch was declared inoperable and the required actions of Technical Specification 3.3.5.1 were entered. This condition could have prevented the HPCS system, a single train safety system, from performing its specified safety function. Troubleshooting is underway to determine the cause of and correct the condition. The licensee notified the NRC Resident Inspector.
The condition reported in Event notification #52848 pursuant to 10 CFR 50.72(b)(3)(v)(D) has been evaluated, and determined not to have met the threshold for classification as an Event or Condition the Could Have Prevented Fulfillment of a Safety Function. Engineering analysis has concluded that the affected switch was capable of performing its required support function to provide the flow signal to the HPCS minimum flow valve logic. Thus, the HPCS system remained capable of performing its specific function for the identified condition. The NRC Resident Inspector has been notified. Notified R4DO (G. Miller). |