ML25055A209

Rv 1A Public Meeting Slides

ML25055A209
Person / Time
Site:	Comanche Peak
Issue date:	02/24/2025
From:	Vistra Operations Company
To:	Mclatchie H NRC/NRR/DORL/LPL4
Lee, Samson
References
Download: ML25055A209 (1)

Text

1 CPNPP RV-1A Public Meeting Discussing extension of thermal relief valve test interval due to delays in procuring acceptable replacement valves.

2 Discussion Topic 1: Plans for Training to Alert Field Personnel The NRC requested that the licensee discuss its plans for training to alert field personnel that the vent valve must be open when the heat exchanger is isolated in addition to the placement of caution tags.

• The information on each caution tag is required to be read and understood prior to valve operation. Field personnel are also required to review the location and legibility of the caution tags quarterly. Therefore, additional training is unnecessary to ensure the heat exchanger is properly vented when isolated.

3 Discussion Topic 2: Plans for Replacement in Forced Outage Prior to the Fall 2026 RFO The NRC requested that the licensee discuss its plans for replacement of these valves if a sufficient duration outage occurs prior to the Fall 2026 RFO at CP Unit 1.

• After receiving acceptable replacement relief valves, the applicable work orders can be added to the forced outage list to ensure station management evaluates completion of the replacement activities during any forced outage of sufficient duration prior to the fall 2026 RFO at Comanche Peak, Unit 1.

• Due to the low risk associated with this extension request and the nuclear safety risk associated with reducing redundancy of safety-related core cooling during either an at power or a forced outage valve replacement activity, NRC reviewers of RV-1 were opposed to relief valve replacement outside of a refueling outage and specifically advocated against adding this activity to a Forced Outage list.

4 Discussion Topic 3: Total Duration of the Interval Extension and Confidence in Valve Operability Over that Duration The NRC requested that the licensee discuss the total duration of the extension of the ASME OM Code testing or replacement interval requirement and the confidence in the capability of the valves to perform their safety function over the duration of the interval extension.

• The total duration of the extension is from the expiration of Alternative Request RV-1 (end of Spring 2025) until the end of the Fall of 2026 when both valves will be replaced during refueling outage 1RF26 - approximately 1.5 years.

• Their safety function is to remain closed to maintain the system pressure boundary, and there is high confidence that the valves will be able to perform their safety function until their replacement no later than the end of Fall of 2026. Considering the 54 relief valves which were incorrectly excluded from the IST Program, there were 19 relief valves in the station service water system (SSW) which were overdue for their test/replacement interval. Site OE during testing/replacement activities which restored compliance proved that all other SSW relief valves (17 of 19) were capable of performing their close safety function. Two of those 17 valves were on the Unit 2 SSW heat exchangers and had the same model and service life as the two valves on the Unit 1 SSW heat exchangers which remain to be restored to compliance.

5 Discussion Topic 4: Status of the Other Valves and Clarification of Number of Valves in the Original RV-1 Alternative Request The NRC requested that the licensee discuss whether the 54 other valves discussed in the original request have been restored to compliance with the ASME OM Code and requested clarification of the number of valves in the original RV-1 Alternative Request.

• 52 of the 54 thermal relief valves which were previously incorrectly excluded from the IST Program are currently in compliance with the current code of record - ASME OM-2017.

Two relief valves remain to be restored to compliance.

• The count of relief valves 18 of 20 noted in Alternative Request RV-1A was an incorrect count that occurred when drafting the request. Of the 54 incorrectly excluded from IST, 20 were in the SSW system and one of those 20 had been tested within 10 years at the time of discovery such that it was in compliance. The count should read 17 of the 19 valves which were not in compliance instead of 18 of the 20 valves.

6 Discussion Topic 5: Any Issues with these Valves Since April 2023 and Plans if the Two Valves Fail Prior to Replacement The NRC requested that the licensee discuss any issues with or repair of these valves from April 2023 to until the present, and (2) the plan if these valves do not perform their required function during the requested extension until the Fall of 2026.

• (1) Summary of Issues with the 54 valves incorrectly excluded since April 2023:

- 6 valves were out of tolerance (typically 150 psig +/- 3%) and opened below the specified set pressure, but well above normal system operating pressure (typically 40 psig).

- 9 valves were out of tolerance but opened between 103% and 110% of the specified set pressure.

- 8 valves were out of tolerance and did not open prior to exceeding 110% of the specified set pressure.

-15 valves passed as-found set pressure testing and were reworked or replaced with rebuilt spare valves to restore compliance.

-14 valves had no issue because they were compliant based on testing under the PM Program

-2 valves are currently not compliant with the ASME OM Code.

7 Discussion Topic 5: Any Issues with these Valves Since April 2023 and Plans if the Two Valves Fail Prior to Replacement The NRC requested that the licensee discuss any issues with or repair of these valves from April 2023 to until the present, and (2) the plan if these valves do not perform their required function during the requested extension until the Fall of 2026.

• (2) The plan if these valves do not perform their required function during the requested extension

-In the unlikely event of a transient that resulted in a stuck open relief valve, the full open relief rate of a valve over the full mission time of the SSW system would be insignificant compared to the available margin in Safe Shutdown Impoundment (SSI) inventory and less than half the capacity of the Auxiliary Building sump pumps. There would be no immediate impact to operability. Plant staff would perform troubleshooting to help the valve return to the closed position and monitor the condition for any further degradation.

8 CPNPP RV-1A Public Meeting End of Presentation