Millstone 3 begins Fall 2026 refueling outage

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Millstone 3, Waterford, Connecticut.

Dominion Energy Nuclear Conn began a routine refueling outage at Millstone 3 on October 12, 2026, starting one day later than its scheduled October 11 start date. The Westinghouse four-loop pressurized water reactor entered this maintenance period following an unscheduled outage-free streak of 351 days.

The 1,243-megawatt unit had completed roughly ninety-three percent of its typical 552-day operating cycle before the shutdown. Millstone 3 maintains a 38.5-day historical average across seventeen prior refuels, while the broader U.S. fleet operates at an 81.3 percent capacity factor with fifteen units currently in refueling outages.

WATERFORD, CT. Refueling activities began at Millstone 3 on Oct 12, 2026. The published schedule had a Oct 11, 2026 start; actual is 1 day later than planned. Planned outage length is 33 days (back to service around Nov 13, 2026).

NukeWorker's start-date projection scores 100% accuracy for this unit.

Across the U.S. fleet of 94 commercial reactors, today's combined capacity factor is 81.3% (15 units currently refueling, 2 units in unscheduled outages), below the 81.8% baseline for this month over the past five years. At the same site, Millstone 2 is running at full power. Peach Bottom 2, Diablo Canyon 1, and Point Beach 1 also began refueling outages within the past week. With the unit offline for refueling, that takes about 994,000 homes' worth of generation off the grid.

Millstone 3 is a 1,243-MW Westinghouse 4-loop PWR operated by Dominion Energy Nuclear Conn (commercial operation since 1986). The utility operates 1 other U.S. nuclear unit. Its operating license runs through 2045 (renewed in 2005). The unit ran at a 84.7% capacity factor in 2025, a steady year.

View Millstone 3's ratings, history, projections, and current status on NukeWorker.

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