Preliminary white safety finding at Comanche Peak prompts NRC conference
The Nuclear Regulatory Commission will hold a regulatory conference Tuesday, May 19, with Vistra Operations Company officials to discuss a preliminary “white” safety finding at Comanche Peak-2.
In a report sent to Vistra Chief Nuclear Officer Ken Peters on April 10, NRC Division of Operating Reactor Safety Acting Director Patricia Vossmar said the finding is a result of an inspection conducted by the NRC at the Glen Rose, Texas, plant from March 22 through April 6. The inspection was a follow-up to an August 2025 incident where a leak rendered a safety chiller in Unit 2, train B inoperable due to low refrigerant pressure.
A white safety finding indicates a low safety significance but may still require additional NRC inspections.
What’s in the report: The NRC’s inspection report says that the chiller first experienced problems on August 14, 2025. The licensee performed repairs and declared the chiller operable one day later, but it continued to lose refrigerant, and Vistra declared the chiller inoperable again on August 24. The licensee deemed the chiller system operable again on August 27.
According to the report, NRC inspectors found the failure to restore the safety chiller to operable status in accordance with technical specifications a “performance deficiency.”
“This failure caused the safety chiller to remain inoperable beyond technical specification limits due to an undetected refrigerant leak at the foul gas check valve inlet fitting,” the report states. “Because safety chilled water supports room cooling for multiple safety-related components, the extended unavailability of the train increased the risk of inadequate heat removal for various safety related systems and components during certain plant conditions.”
According to the report, the finding comes with an associated apparent violation that is being considered for escalated enforcement: “The apparent violation involves failure of the licensee to restore safety chiller 2-06 within Technical Specification 3.7.19 allowed outage time as well as a failure to properly pre-plan and perform maintenance on the 2-06 safety chiller as required by Technical Specification 5.4.1.”
NRC documents say the agency will complete its evaluation and issue a final safety significance determination and enforcement decision in writing within 90 days from the issuance of the letter.
Meeting details: According to the NRC, the May 19 meeting will allow Vistra officials to provide their take and any additional information to the NRC before the agency makes a final determination. No decisions on the final safety significance or any potential enforcement will be made at the meeting.
The meeting is scheduled for 9 a.m. central time at the NRC’s Region IV office in Arlington, Texas. Details on how the public can participate in the conference by phone or online can be found in the meeting notice on the NRC website.
