LaSalle 1 trips offline, unscheduled outage underway

[News Wire]

LaSalle 1 began an unscheduled forced short outage on May 27, 2026, ending a 147-day streak of outage-free operation. NukeWorker projections estimate the duration of this event at about 4 days.

This forced outage is the first for the 1,131-MW General Electric BWR/5 unit in 2026, compared to two forced outages recorded during 2025. Constellation Nuclear operates this unit along with 20 other U.S. nuclear units. Across the industry, the current fleet capacity factor is 94.4 percent, with 94 units online, four in refueling, and one unit currently in an unscheduled outage.

MARSEILLES, IL — An unscheduled outage at LaSalle 1 began on May 27, 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 2 unscheduled outages in all of 2025. The unit had just returned to service on Feb 27, 2026 from a 19-day refueling outage.

Based on the unit's history and similar reactor types, projected total duration is about 4 days. NukeWorker's forced-outage projection scores 95% duration accuracy for this unit, with past calls usually landing within about 2 days.

Across the U.S. fleet of 94 commercial reactors, today's combined capacity factor is 94.4% (4 currently in refueling, 1 in unscheduled outages), above the 87.0% baseline for this month over the past five years. At the same site, LaSalle 2 is running at full power.

LaSalle 1 is a 1,131-MW General Electric BWR/5 operated by Constellation Nuclear (commercial operation since 1984). At full power, it supplies enough electricity for roughly 905,000 homes. The utility operates 20 other U.S. nuclear units. Its operating license runs through 2042 (renewed in 2016).

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View LaSalle 1'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.

[News Wire]

LaSalle 1 returned to service on May 30, 2026, following a four-day forced outage that began on May 27. The actual duration of the outage was three days shorter than the initial seven-day projection provided by NukeWorker.

This event marks the first forced outage for the 1,131-MW General Electric BWR/5 unit in 2026, compared to two forced outages recorded during 2025. NukeWorker maintains a 95 percent accuracy rate for forced-outage duration projections on this unit across ten prior events. Constellation Nuclear operates LaSalle 1 along with 20 other U.S. nuclear units. Currently, the broader fleet operates at a 97.5 percent capacity factor across 94 units, with two units in refueling and zero units in unscheduled outages.

LaSalle 1 returned to service on May 30, 2026 after a 4-day unscheduled outage that began on May 27, 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 4 days at outage start; actual duration matched within a day.

The 4-day outage removed roughly 100,000 MWh from the grid, worth approximately $4 million at recent wholesale prices, equivalent to a year's electricity for about 9,200 homes.

View LaSalle 1'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.