ENS 54452
ENS Event | |
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14:08 Dec 18, 2019 | |
Title | Secondary Containment Pressure Degraded |
Event Description | 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. |
Where | |
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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:+1.32 h0.055 days <br />0.00786 weeks <br />0.00181 months <br />) | |
Opened: | Ethan Hauser 15:27 Dec 18, 2019 |
NRC Officer: | Ossy Font |
Last Updated: | Dec 18, 2019 |
54452 - NRC Website
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Unit 2 | |
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Reactor critical | Critical |
Scram | No |
Before | Power Operation (100 %) |
After | Power Operation (100 %) |