Event Notification Report for September 11, 2022

PART 21 - FLOWSERVE SOLENOID VALVE DEFICIENCY REPORT

The following is a synopsis of information provided by Flowserve via fax:

Flowserve Corporation hereby submits the enclosed written notification of the identification of a defect, in accordance with the requirements of 10 CFR 21.21(d)(3)(ii). This notification pertains to the failure of a solenoid valve (model 38878-8) at Catawba Nuclear Station.

List of plants / customers potentially impacted:
Duke - Catawba
Luminant - Comanche Peak
Exelon - Byron
Exelon - Braidwood
NextEra Energy - Seabrook

The solenoid valve received by Duke Energy failed to shift position when the coil was initially energized. This solenoid valve is part of the feedwater isolation valve assembly and failure to shift will prevent the feedwater isolation valve from closing on demand.

Flowserve was initially notified on September 11, 2022. Flowserve provided response to Duke on September 15, 2022 to confirm that Flowserve would perform the evaluation within 45 days upon receipt of the solenoid valve. Flowserve received the solenoid valve for evaluation on October 5, 2022.

During Flowserve's investigation into the root cause of the solenoid valve failure, Flowserve was unable to replicate the failure. Based on examination of the solenoid valve components, excess thread lock compound had been applied to the set screw and nut on the coil cap. The excess thread lock compound then ran down the coil cap and wicked between the coil cap outside diameter and the end cap inside diameter. Once this excess thread lock compound cured, the coil cap was locked in the de-energized position, preventing the coil cap from shifting. After the customer left the solenoid valve energized for 10 minutes, the coil cap broke free from de-energized position and was able to shift freely. In the procedure for assembly and testing of this solenoid valve, the solenoid valve is not energized after application of the thread lock compound.

Flowserve will (1) revise the assembly and test procedure for the Model 38878 solenoid valve to add a final test after the thread lock component has been applied and been allowed to cure to verify the solenoid valve shifts when energized, and (2) provide training to assembly and test personnel on the importance of ensuring that excess thread lock compound has not been applied.

These actions will be completed by December 15, 2022.

Nuclear power plants with model 38878 solenoid valves that have not undergone acceptance testing should verify that these suspect solenoid valves will shift on demand when energized.

For additional information, please contact Kayn Dills, Flowserve Corp Quality Manager (800-225-6989)