Diablo Canyon 1 wraps Fall refuel in 29 days, 6 days ahead of schedule

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Diablo Canyon 1, Avila Beach, California.

Diablo Canyon 1 finished its routine refueling outage 6 days ahead of the planned 35-day schedule. The outage lasted 29 days, which is 11.1 days below the average of 17 prior refuels. The unit returned to 99% power by Nov 12, 2026.

29 days outage · 6 days ahead of schedule · 1,122 MW back at full power

After 29 days offline for its Fall 2026 refueling outage, Diablo Canyon 1 reached full power on Nov 12, 2026. The outage began on Oct 11, 2026. The reactor was critical by the NRC's Nov 9, 2026 report and back on the grid by Nov 11, 2026. First power to full power took 3 days.

The published schedule had it at 35 days (Oct 12, 2026 to Nov 16, 2026), so the actual ran 6 days shorter than planned.

The outage ran about 11 days shorter than the unit's 17-cycle average of 40.1 days.

Counting the 29 days offline and the climb back to full power, the outage cost roughly 827,000 MWh of generation, worth approximately $33 million at recent wholesale prices.

Across the U.S. fleet of 94 commercial reactors, today's combined capacity factor is 84.7% (11 units currently refueling, 4 units in unscheduled outages), below the 88.0% baseline for this month over the past five years. At the same site, Diablo Canyon 2 is running at full power. Robinson 2, Waterford 3, Comanche Peak 1, and Farley 2 also completed refueling outages within the past week.

Diablo Canyon 1 is a 1,122-MW Westinghouse 4-loop PWR operated by Pacific Gas & Electric (commercial operation since 1985). At full power, it supplies enough electricity for roughly 898,000 homes. The utility operates both units at this site and no other U.S. nuclear plant. Its operating license runs through 2064 (renewed in 2026). The unit ran at an 88.9% capacity factor in 2025, a steady year.

View Diablo Canyon 1's ratings, history, projections, and current status on NukeWorker.

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