| ENS 57334 | Nine Mile Point | 23 September 2024 11:20:00 | Automatic Reactor Scram Due Turbine Trip | The following information was provided by the licensee via phone and email:
On 9/23/2024 at 0720 EDT, with Unit 2 in mode 1 at 100 percent power, the reactor automatically scrammed due to turbine stop valve closure on a turbine trip. The scram was not complex. Due to the reactor protection system (RPS) actuation while critical, this event is being reported as a four hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B). Following the scram, reactor water level dropped below level 2 (108.8 inches), starting high pressure core spray (HPCS) and reactor core isolation cooling (RCIC); both injected into the reactor. RCIC is being used with turbine bypass valves to remove decay heat. Due to the emergency core cooling systems HPCS and RCIC discharging into the reactor coolant system, this event is being reported a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(A), and an eight hour, non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A). In addition, with reactor water level below level 2 (108.8 inches), primary containment isolation signals actuated resulting in group 2 recirculation sample system isolation, group 3 traveling in-core probe (TIP) isolation valve isolation, group 6 and 7 reactor water cleanup isolation, group 8 containment isolations, and group 9 containment purge isolations. This event is being reported as an eight hour, non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A). Operations responded using procedure N2-EOP-RPV (1-3) and stabilized the plant in mode 3. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector was informed. There was no impact on Unit 1.
- * * UPDATE ON 9/23/2024 AT 1550 EDT FROM RYAN LOOMIS TO IAN HOWARD * * *
On 9/23/2024 at 1156 EDT Constellation communications provided a media statement to Oswego area news media contacts summarizing the events that had occurred at Nine Mile Point Unit 2 and FitzPatrick Unit 1. This is a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(xi). The NRC Senior Resident Inspector has been notified.
Notified R1DO (Dimitriadis), NRR EO (Felts), and IR MOC (Grant). |
| ENS 57387 | Brunswick | 10 September 2024 17:42:00 | 60-DAY Optional Telephonic Notification of Invalid Actuation of Containment Isolation Valves | The following information was provided by the licensee via phone and email:
This 60-day optional telephone notification is being made in lieu of a licensee event report (LER) submittal as allowed by 10 CFR 50.73(a)(1). This notification is made pursuant to the reporting requirements specified in 10 CFR 50.73(a)(2)(iv)(A) for an invalid actuation of one of the systems listed in 10 CFR 50.73(a)(2)(iv)(B).
At approximately 1342 EDT, on September 10, 2024, the reactor water cleanup (RWCU) inboard primary containment isolation valve (PCIV), and the reactor recirculation pump sample inboard PCIV, unexpectedly closed. At the time of this event, work was in progress replacing a control relay in the residual heat removal (RHR) shutdown cooling inboard isolation PCIV circuitry. This relay replacement required lifting the leads of several wires. The neutral side of the relay was electrically connected with the actuation logic for the inboard RWCU and reactor recirculation pump sample PCIVs; the lifting of this lead resulted in the unexpected closure of these PCIVs.
The actuation was not initiated in response to actual plant conditions, nor an intentional manual initiation, and there were no parameters satisfying the requirements for initiation of the system. Therefore, this event has been determined to be an invalid actuation.
During this event the PCIVs functioned successfully, and the actuations were complete. This event did not result in any adverse impact to the health and safety of the public.
The NRC Resident Inspector was notified.
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
Unit 2 was not affected. |