ENS 56070
ENS Event | |
|---|---|
18:30 Aug 23, 2022 | |
| Title | Safety Equipment Failed to Function - Criticality Accident Alarm System Loss of Power |
| Event Description | The following information was provided by Westinghouse via email:
At approximately 1430 [EDT] on 8/23/2022, a ground fault caused a circuit breaker to trip, causing a loss of power to the Criticality Accident Alarm System (CAAS) Stations 18 and 19 at the Columbia Fuel Fabrication Facility (CFFF). This removed all power to the stations, as the circuit breaker is between the UPS (ultimate power source) and the detectors. Upon the loss of power, a signal was received at the manned guard station, as designed, providing both visual indication and an audible alarm that Stations 18 and 19 were disabled. Notifications and actions were performed in accordance with internal response procedures. It was determined that the area of lost coverage was limited to part of the outdoor UF6 cylinder storage pad. Special Nuclear Material (SNM) movements at the UF6 cylinder storage pad were immediately suspended. No personnel were in the affected area at the time. Power was restored to the circuit at approximately 1540 and CAAS detectors 18 and 19 were placed back in operation at approximately 1600. Operations were cleared to resume at that time. A reportability evaluation was performed and determined there was redundant equipment available and operable to perform the safety function of the out of service detectors and, therefore, was not reportable. On 8/25/2022, site electrical engineering staff completed their causal analysis and extent of condition review of the incident on 8/23/2022. The understanding of the condition during the event was that two breakers on the sub-panel tripped, one which removed power from Criticality Stations 18 and 19. In fact, the ground fault caused the breaker to the sub-panel to trip and the extent of condition review on 08/25/2022 at 0919 determined that a CAAS horn loop consisting of 7 horns and one strobe light were also disabled. If the CAAS is out-of-service, CFFF is required within one hour to suspend movement and processing of SNM in the coverage area until the process is brought to a safe shutdown condition. In the unlikely event of a criticality anywhere in the plant, the emergency response is to evacuate the entire plant. Therefore, since a portion of the horn system was unavailable all SNM movements should have been suspended in the plant within an hour. It was not recognized until completion of the extent of condition review that the horn loop was out of service for approximately 90 minutes due to this incident. The fire alarm speaker system was operable at the time and the station guard would have made an announcement in the event of a criticality. The fire alarm system does not meet all the requirements in ANSI/ANS-8.3 (1997) for CAAS response. The condition is being reported in accordance with 10 CFR 70.50(b)(2). Specifically, the equipment required by 70.24, was inoperable for approximately 30 minutes outside the window allowed by the license, without a cessation of movement and processing of SNM, and with no redundant equipment available and operable that met all the requirements of ANSI/ANS-8.3." The NRC Region was notified. |
| Where | |
|---|---|
| Westinghouse Electric Corporation Columbia, South Carolina (NRC Region 2) | |
| License number: | SNM-1107 |
| Reporting | |
| 10 CFR 70.50(b)(2) | |
| Time - Person (Reporting Time:+62.67 h2.611 days <br />0.373 weeks <br />0.0858 months <br />) | |
| Opened: | Patrick Donnelly 09:10 Aug 26, 2022 |
| NRC Officer: | Karen Cotton-Gross |
| Last Updated: | Aug 26, 2022 |
| 56070 - NRC Website | |
Westinghouse Electric Corporation with 10 CFR 70.50(b)(2) | |
WEEKMONTHYEARENS 560702022-08-23T18:30:00023 August 2022 18:30:00
[Table view]10 CFR 70.50(b)(2) Safety Equipment Failed to Function - Criticality Accident Alarm System Loss of Power 2022-08-23T18:30:00 | |