Millstone 2 trips offline, unscheduled outage underway

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Millstone 2 began an unscheduled forced short outage on 2026-06-05. This event ended the unit's unscheduled-outage-free streak at 1591 days.

This forced outage is the first for the 853-MW Combustion Engineering pressurized water reactor in 2026, following a year with zero forced outages in 2025. Dominion Energy Nuclear Conn operates this unit and one other U.S. nuclear unit. Across the 94 units in the current fleet, the capacity factor is 97.3 percent, with one unit currently in refueling and one unit in an unscheduled outage.

WATERFORD, CT — Millstone 2 entered an unscheduled outage on Jun 5, 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. The unit had just returned to service on May 13, 2026 from a 31-day refueling outage.

Across the U.S. fleet of 94 commercial reactors, today's combined capacity factor is 97.3% (1 currently in refueling, 1 in unscheduled outages), above the 95.3% baseline for this month over the past five years. At the same site, Millstone 3 is running at full power.

Millstone 2 is an 853-MW COMB CE PWR operated by Dominion Energy Nuclear Conn (commercial operation since 1975). At full power, it supplies enough electricity for roughly 682,000 homes. The utility operates 1 other U.S. nuclear unit. Its operating license runs through 2035 (renewed in 2005).

View Millstone 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.