ENS 56866
ENS Event | |
|---|---|
15:56 Nov 20, 2023 | |
| Title | Hpci Declared Inoperable |
| Event Description | The following information was provided by the licensee via email:
At 0956 [CST] on November 20, 2023, accumulated gas was identified in the Dresden Unit 2 high pressure coolant injection (HPCI) system discharge header. As a result, the HPCI system was declared inoperable. Since HPCI is a single-train system, this is a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). The HPCI system was subsequently vented, and the accumulated gas has been removed, restoring the Dresden Unit 2 HPCI system to an operable status. All other emergency core cooling systems remained operable during this time period. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The licensee administratively verified the isolation condenser was operable after declaring HPCI inoperable as required by technical specifications. The licensee stated there was no increase in plant risk. The cause of gas accumulating in the Dresden Unit 2 HPCI discharge header is under investigation, and this issue has been entered into the licensees corrective action program.
Further analysis demonstrated that the Unit 2 high pressure coolant injection (HPCI) system remained operable with the level of voiding found in the HPCI discharge line. This analysis also found that the additional loads that would be present if the HPCI system were actuated with this level of voiding are within design limits of the HPCI system piping and supports. Based on these results, this event is not reportable under 10 CFR 50.72(b)(3)(v)(D), `Any event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident. Therefore, EN 56866 submitted on November 20, 2023, is being retracted. The NRC Resident Inspector has been notified. Notified R3DO (Havertape) |
| Where | |
|---|---|
Dresden  Illinois (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| LER: | 05000237/LER-2023-001 HPCI Inoperable Due to Air Void Accumulation |
| Time - Person (Reporting Time:+1.95 h0.0813 days <br />0.0116 weeks <br />0.00267 months <br />) | |
| Opened: | Edward Burns 17:53 Nov 20, 2023 |
| NRC Officer: | Ernest West |
| Last Updated: | Apr 5, 2024 |
| 56866 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |