South Texas 2 trips offline, unscheduled outage underway

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South Texas 2, Palacios, Texas.

South Texas 2 began an unscheduled forced short outage on June 18, 2026. This event ended the unit's unscheduled-outage-free streak at 205 days.

This is the first forced outage for the 1,280-MW Westinghouse 4-loop PWR in 2026, matching the total count recorded for the entire year of 2025. STP Nuclear Operating manages this unit and one other U.S. nuclear unit. Across the industry, the fleet currently maintains a 98.2 percent capacity factor with 94 units online, one unit in refueling, and one unit in an unscheduled outage. The unit has been in commercial operation since 1989.

PALACIOS, TX — South Texas 2 entered an unscheduled outage on Jun 18, 2026. The NRC has not yet issued an event notification for this trip; this post will be updated if one is filed.

This is the first unscheduled outage of 2026 for the unit, which had 1 unscheduled outage in all of 2025.

Across the U.S. fleet of 94 commercial reactors, today's combined capacity factor is 98.2% (1 in unscheduled outages), above the 95.3% baseline for this month over the past five years. At the same site, South Texas 1 is running at full power.

South Texas 2 is a 1,280-MW Westinghouse 4-loop PWR operated by STP Nuclear Operating (commercial operation since 1989). At full power, it supplies enough electricity for roughly 1 million homes. The utility operates 1 other U.S. nuclear unit. Its operating license runs through 2048 (renewed in 2017).

Heading to Palacios, TX for support work? Current per-diem averages $110/night lodging plus $68/day meals (total $178/day), and Unemployment Benefits are $605 weekly. See open nuclear jobs in Texas on NukeWorker.

View South Texas 2's ratings, history, projections, and current status on NukeWorker. This thread will be updated when the unit returns to service.

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Sources: NRC Daily Reactor Power Status reports, utility-published outage schedules, and NukeWorker's projections.

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Follow-up: the NRC has filed an event notification on Jun 16, 2026 for the South Texas 2 trip first reported in this thread. NRC scram report (type: P, code: A, docket 05000499). View the NRC event notification.

AUTOMATIC REACTOR TRIP The following information was provided by the licensee via phone and email: "At 2325 [CDT] on 06/17/2026, [South Texas Project] Unit 2 reactor automatically tripped following a lockout of the Unit main and [auxiliary] transformers. This trip was not complex with all systems responding as normal post trip. "Auxiliary feedwater actuated and standby diesel generators (DG) 21 and 23 started to carry their respective engineered safety features (ESF) busses. "The Unit 2 balance of plant DG was out of service at the time of the trip. This issue resulted in no power to the Unit 2 instrument air compressors. The unit was cooled down utilizing steam generator pressure operated relief valves (PORV). "Due to the reactor protection system actuation while criti...

View South Texas 2's ratings, history, projections, and current status on NukeWorker.

Sources: NRC Daily Reactor Power Status reports, utility-published outage schedules, and NukeWorker's projections.

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South Texas 2 returned to service on June 27, 2026, following a 10-day unscheduled outage caused by a scram.

This event marks the first forced outage for the 1,280-MW Westinghouse 4-loop PWR in 2026, matching the total count for the entire 2025 calendar year. NukeWorker has maintained a 90% accuracy rate within tolerance for forced-outage duration projections across four prior events at this unit. STP Nuclear Operating manages this site and one other U.S. nuclear unit. Currently, the national fleet of 94 units is operating at a 99.6% capacity factor with no units in refueling or unscheduled outages.

South Texas 2 returned to service on Jun 27, 2026 after a 10-day unscheduled outage that began on Jun 18, 2026. A multi-day outage in this range typically points to a single equipment fix rather than a major component issue.

NukeWorker's projection had this at about 7 days at outage start; actual was 3 days longer.

The 10-day outage removed roughly 283,000 MWh from the grid, worth approximately $11 million at recent wholesale prices, equivalent to a year's electricity for about 26,000 homes.

View South Texas 2's ratings, history, projections, and current status on NukeWorker.

Want the full picture? Subscribe to the NukeWorker outage schedule for every current and upcoming U.S. nuclear outage.

Sources: NRC Daily Reactor Power Status reports, utility-published outage schedules, and NukeWorker's projections.