Event Notification Report for February 19, 2025

PART 21 - EDG ROOM VENTILATION FAN CONTROLLER FAILURE

The following information was provided by the licensee via phone or email:

"Catawba Nuclear Station has determined that a defect associated with Love Controllers identified with Limpet supplier part number 54-834-838-8187-8160-8134-8174 is reportable under 10 CFR Part 21.

"The subject parts were procured as commercial grade items and dedicated by Duke Energy, Inc., solely for use at Catawba Nuclear Station. Manufacturer circuit board workmanship issues associated with the Love controller resulted in a failed controller installed in Catawba's 2A1 emergency diesel generator room ventilation train and resulted in Catawba submitting licensee event report 2024-001-00. The loss of one emergency diesel room ventilation fan, under certain conditions, could cause a loss of safety function at elevated outside air temperatures and could result in a substantial safety hazard. All other Love controllers installed and in Duke Energy's warehouse were subsequently inspected for similar workmanship issues [with no issues found].

"The NRC Senior Resident Inspector has been notified. No other nuclear plants were affected as the part has not been sold or transferred to another facility."

Notified by:

Scott Milton
Nuclear Support Services Manager
Catawba Nuclear Station
Desk: 803-701-3488

TWO OF THREE ECCS TRAINS DECLARED INOPERABLE

The following information was provided by the licensee via phone and email:

"On 02/18/2025, at 0400 CST, train `C' essential cooling water was declared inoperable for scheduled maintenance. This cascades down to train `C' emergency core cooling system (ECCS), rendering it inoperable. Train `C' essential cooling water was declared operable on 02/18/2025, at 1207; however, train `C' essential chiller remained inoperable due to ongoing maintenance, which renders train `C' ECCS inoperable.

"On 02/19/2025, at 0324, train `B' ECCS was declared inoperable due to challenging control room habitability. The mitigating strategy of placing high head safety injection pump `1B' in pull to lock was completed at 0749 on 2/19/2025.

"On 02/19/2025, at 0324, Technical Specification 3.5.2 action `b' was entered due to two trains of ECCS being inoperable. This action requires that at least two trains of ECCS are restored to operability within 1 hour or apply the requirements of the CRMP (Configuration Risk Management Program).

"On 02/19/2025, at 0424, the CRMP was entered based on two ECCS trains remaining inoperable for longer than 1 hour.

"This condition resulted in the inoperability of two of the three safety trains required for the accident mitigating function including: high head safety injection, low head safety injection, and containment spray. This is an 8-hour reportable condition per 10CFR50.72(b)(3)(v)(D) because it could affect the ability to mitigate the consequences of an accident.

"Unit 1 remains in mode 1 at 100 percent power. The NRC Resident Inspector has been notified."

The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:

With two ECCS trains inoperable, the licensee will enter a shutdown technical specification action statement on 3/13/2025.