ENS Event | |
|---|---|
07:42 Sep 25, 2021 | |
| Title | Loss of Uninterruptible Power Supply Resulted in Isolation of Two Emergency Condensers |
| Event Description | On 9/25/2021 at 0342 EDT, Nine Mile Point Nuclear Station Unit 1 experienced a loss of the Uninterruptible Power Supply (UPS), UPS 162A, which resulted in a loss of Reactor Protection System (RPS) Bus 11. This resulted in an isolation of both No. 11 and No. 12 Emergency Condensers. Emergency Condenser No. 11 was returned to standby on 9/25/2021 at 0420 EDT and Emergency Condenser No. 12 was returned to standby on 9/25/2021 at 0429 EDT.
This 8-hour non-emergency report is being made based upon requirements of 10 CFR 50.72(b)(3)(v)(B) which states: 'Licensee shall notify the NRC of any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to: (B) remove residual heat.' The NRC Senior Resident was informed. |
| Where | |
|---|---|
Nine Mile Point  New York (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat | |
| LER: | 05000220/LER-2021-002 Isolation of Both Emergency Condensers Due to Loss of UPS 162A |
| Time - Person (Reporting Time:+1.57 h0.0654 days <br />0.00935 weeks <br />0.00215 months <br />) | |
| Opened: | Amanda Tetro 09:16 Sep 25, 2021 |
| NRC Officer: | Donald Norwood |
| Last Updated: | Sep 25, 2021 |
| 55492 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 554922021-09-25T07:42:00025 September 2021 07:42:00
[Table view]10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Loss of Uninterruptible Power Supply Resulted in Isolation of Two Emergency Condensers ENS 521332016-07-29T03:57:00029 July 2016 03:57:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Temporary Loss of Power to the Emergency Condenser ENS 439902008-02-16T00:02:00016 February 2008 00:02:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Potential Inoperability of Emergency Core Cooling Systems Due to an Unalalyzed Condition 2021-09-25T07:42:00 | |