15:00 Oct 3, 2017
Secondary Containment Inoperable Due to Unexpected Isolation of Exhaust Valve
On October 3, 2017, at 0800 PDT, Reactor Building (Secondary Containment) pressure momentarily rose above the Technical Specification (TS) limit. Secondary Containment was declared inoperable and TS Action Statement 18.104.22.168.A was entered. The pressure rise was due to unexpected isolation of an exhaust valve in the Reactor Building ventilation system during electrical switchgear inspections. The cause of the closure is still under investigation.
The Control Room operators reopened the Reactor Building exhaust valve and pressure returned to within limits automatically. Secondary Containment was declared operable at 0802 PDT and TS Action Statement 22.214.171.124.A was exited.
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 NRC Resident Inspector has been notified.
|Columbia Generating Station |
Washington (NRC Region 4)
|10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material|
10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident
|Time - Person (Reporting Time:+1.97 h|
16:58 Oct 3, 2017
|NRC Officer:||Jeff Herrera|
|Last Updated:||Oct 3, 2017|
|52999 - NRC Website|