15:30 Oct 20, 2019
Control Room Envelope Breach
At 1030 CDT, it was discovered that the loop seal on the condensate drain was empty for VUC-9 Control Room AC Unit. This creates a breach in the Control Room envelope. Unit 2 entered [Technical Specification] T.S. 22.214.171.124 Action D. Unit 1 is in Mode 6; therefore, not in a mode of applicability.
Compensatory action were being performed and the licensee was in the process of sealing the loop.
The licensee will notify the NRC Resident Inspector.
This report is being retracted. The Control Room Envelope (CRE) provides a safety function which limits radiological dose to occupants to no more than 5 rem for 30 days post-accident. The dose limitation assumes the occupants are stationed within the CRE 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> a day for the entire 30-day period. The CRE also functions to protect occupants from potential hazards such as smoke or toxic chemicals.
The CRE is declared inoperable when a potential breach is identified, regardless of the ability to seal the breach. With respect to the event of October 20, 2019, the water level in a loop seal could not be maintained at the desired level. Subsequent evaluation determined that sufficient water was maintained in the loop seal to prevent a breach of the CRE.
The subject reporting criterion is based on the assumption that safety-related systems, structures, and components (SSCs) may no longer be capable of mitigating the consequences of an accident. In accordance with NUREG 1022, 'Event Report Guidelines 10 CFR 50.72 and 50.73,' a report may be retracted based on a revised operability determination. The CRE remained operable; therefore, this report may be retracted.
The licensee notified the NRC Resident Inspector.Notified R4DO (Young).
|Arkansas Nuclear |
Arkansas (NRC Region 4)
|10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident|
|Time - Person (Reporting Time:+3.85 h0.16 days <br />0.0229 weeks <br />0.00527 months <br />)|
19:21 Oct 20, 2019
|NRC Officer:||Ossy Font|
|Last Updated:||Oct 24, 2019|
|54339 - NRC Website|