ENS 56637
ENS Event | |
|---|---|
13:24 Jul 25, 2023 | |
| Title | |
| Event Description | The following information was provided by the licensee via email:
At 0924 [EDT] on July 25, 2023, it was discovered that both trains of control room air conditioning system were simultaneously inoperable due to an inoperable control room envelope boundary. The boundary was restored at 0925 [EDT] on July 25, 2023. This condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. There has been no impact to Unit 3 which remains at 100% power.
The licensee determined in a subsequent engineering evaluation of the conditions that existed at the time, that the access hatch being open did not have an adverse impact upon the control room emergency ventilation system and the control room envelopes boundary's ability to perform their safety function including: Radiation dose to the occupants did not exceed the licensing basis, design basis accident calculated value. Protection of control room occupants from hazardous chemicals and smoke. Therefore, this condition is not reportable and NRC Event EN56637 is being retracted. The basis for this conclusion has been provided to the NRC Resident Inspector. Notified R1DO (Lally) |
| Where | |
|---|---|
Millstone  Connecticut (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+2.7 h0.113 days <br />0.0161 weeks <br />0.0037 months <br />) | |
| Opened: | Jason Parr 16:06 Jul 25, 2023 |
| NRC Officer: | Thomas Herrity |
| Last Updated: | Sep 26, 2023 |
| 56637 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (86 %) |
| After | Power Operation (86 %) |