Monticello trips offline, unscheduled outage underway

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Monticello, Monticello, Minnesota.

Monticello entered an unscheduled forced short outage on August 10, 2026, ending a 130-day streak of outage-free operation. This event marks the second forced outage for the 617-MW General Electric BWR/3 unit during the 2026 calendar year.

The unit, which has been in commercial operation since 1971, recorded four forced outages throughout 2025. Northern States Power Co - Minnesota operates this facility along with two other U.S. nuclear units. Across the industry today, 94 units are maintaining a 97.9 percent capacity factor, with this unit currently representing the only facility in an unscheduled outage.

MONTICELLO, MN. Monticello dropped offline on Aug 10, 2026, beginning an unscheduled outage. The NRC has not yet issued an event notification for this trip; a follow-up reply will be posted here if one is filed.

This is the second unscheduled outage of 2026 for the unit, which had 4 unscheduled outages in all of 2025.

Across the U.S. fleet of 94 commercial reactors, today's combined capacity factor is 97.9% (1 unit in an unscheduled outage), above the 97.9% baseline for this month over the past five years. While the unit is down, that takes about 494,000 homes' worth of generation off the grid.

Monticello is a 617-MW General Electric BWR/3 operated by Northern States Power Co - Minnesota (commercial operation since 1971). The utility operates 2 other U.S. nuclear units. Its operating license runs through 2050 (renewed in 2024).

View Monticello'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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Monticello returned to service on August 27, 2026, following an 18-day forced extended outage. The unit resumed operations six days ahead of the initial 24-day projection provided by NukeWorker.

This event marks the second forced outage for the 617-MW General Electric BWR/3 in 2026, compared to four forced outages recorded during the 2025 calendar year. Northern States Power Co - Minnesota operates this unit alongside two other U.S. nuclear units. Across the industry, the current fleet capacity factor is 97.7 percent with 94 units online. At the time of this return, Saint Lucie 1 remained the only other U.S. unit in an unscheduled outage.

Monticello returned to service on Aug 27, 2026 after a 18-day unscheduled outage that began on Aug 10, 2026. An outage of this length is on the longer end for a forced event, often involving inspection or repair work beyond the initial trip cause.

The 18-day outage removed roughly 245,000 MWh from the grid, worth approximately $10 million at recent wholesale prices, equivalent to a year's electricity for about 23,000 homes.

View Monticello'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.