NRC reviewing 2 unplanned shutdowns at South Texas Project

The U.S. Nuclear Regulatory Commission began a special inspection last week at South Texas Project nuclear power plant into two incidents at the site, which led to separate, unplanned shutdowns of both Units 1 and 2.

• On May 12, a transformer that supplies off-site power to the station shut down unexpectedly and took Unit 2 off line.
• On July 24, a fire in an electrical switchyard at the site caused an unplanned shutdown of Unit 1.

The NRC will study the unexpected safety equipment issues from each event.

Quotable: "While these events didn't present a threat to public health and safety, we want to conduct a thorough review of the circumstances that led to these unplanned shutdowns," said John Monninger, the NRC's Region IV administrator. "We will review the company's actions in response to these events and determine whether appropriate steps are being taken to address equipment issues."

During each event, the NRC resident inspectors independently monitored plant conditions and safety, the STP Nuclear Operating Company's initial corrective actions, and plant's successful restarts.

About the plant: The two-unit South Texas Project is located in Bay, Texas, about 90 miles southwest of Houston. It generates 2,501 megawatts of electricity. Among the youngest reactors in the U.S. fleets, Unit 1's initial license does not expire until 2047, and Unit 2's goes until 2048.

Constellation acquired a 44 percent ownership stake from NRG Energy in late 2023. Two Texas-based companies, Austin Energy and CPS Energy, have ownership stakes of 40 percent and 16 percent, respectively.

What's next: The NRC will issue its report within about 45 days and make it publicly available on the NRC website.