Diablo Canyon 1

Refueling Outage · Day 9

Pacific Gas & Electric·Avila Beach, CA·PWR·1,122 MWe

Data refreshed 5.3h ago Rx Status: Oct 19, 2026 at 5:12 AM (M-F)

Outage History Daily Power Log Get alerts

Reactor Status Timeline

Refueling Outage · Day 9 NRC data, Mon to Fri ? Actual daily reactor status from NRC reports (Mon to Fri) and the current state. What is coming -- the utility's published Scheduled outage and NukeWorker's model Projection -- is part of a subscription. Colored by status. How far ahead you can see depends on your plan.
Nov2025DecJan2026FebMarAprMayJunJulAugSepOctNovOnline: Oct 19, 2025 to Dec 16, 2025Forced Outage: Dec 17, 2025 to Dec 18, 2025Reduced Power: Dec 19, 2025Online: Dec 20, 2025 to Feb 20, 2026Reduced Power: Feb 21, 2026 to Feb 23, 2026Online: Feb 24, 2026 to Feb 27, 2026Reduced Power: Feb 28, 2026 to Mar 1, 2026Online: Mar 2, 2026 to Oct 10, 2026Refueling Outage (1R26): Oct 11, 2026 to Oct 19, 2026Today
OnlineReduced PowerRefueling OutageForced Outage
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Composite Operational Excellence Score (0-100) — average percentile rank across 7 dimensions in three sub-scores: Reliability (capacity factor, forced outage days, B2B avg streak), Efficiency (fuel utilization, refuel duration), and Discipline (startup duration, scram count). 5-year window. Higher = more operationally excellent. Click to see the full breakdown.
   
Excellence
Rank locked · 93 units
Subscribers
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Days of continuous operation since the last outage ended (Started 2026-10-19). Has forced outage(s) since last refueling.
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Current Run
offline
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Longest recorded period of continuous operation between outages (2017-06-21 to 2019-02-10).
599
Record Run
days
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold set for this unit with no trips to 0% power.
12
B2B Runs
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Lifetime capacity factor: average power level across all recorded days (100% = always at full power).
90.2%
Capacity Factor
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Net electricity actually generated over the most recent 12 months reported by the U.S. EIA (Form EIA-923), summed across every unit at this plant. Authoritative actuals, not an estimate.
18.29 TWh
Net Generation
EIA-923 · 12 mo to 2026-07 · plant total
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Total number of scheduled refueling outages detected in the historical data.
18
Outages
since 1999
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Average time from first power generation (>0%) to sustained full power (≥95% for 2+ days) across the last 3 scheduled outages. Click to compare against the fleet on the Operator Efficiency Leaderboard.
6.3
Avg Startup
days (last 3)
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Average fuel utilization — percent of the designed fuel cycle that this unit consumes before refueling, derived from the historical burn-down trajectory. Higher = more efficient operator (refuels with less margin remaining; closer to coastdown). Computed as 100% minus the unit's average refuel-point fuel %, using the last 3 years where available, otherwise lifetime average. Click to compare against the fleet on the Operator Efficiency Leaderboard.
97.4%
Fuel Utilization
3yr avg

Reactor Status

Current Reactor Status Oct 19, 2026

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Current power output from NRC daily reactor status reports, updated Monday through Friday, except federal holidays. The gauge shows power level as a percentage of rated capacity. The sparkline shows the last 14 days of power history. Click to view the full unit dashboard.
Diablo Canyon 1 is OFFLINE (9 Days) at 0% of rated power as of Oct 19, 2026. This outage is RFO 1R26. Over the last 14 reported days it has run between 0% and 100% power.
Diablo Canyon 1 is OFFLINE (9 Days) Get alerts
0
PERCENT
0 200 400 600 800 1000 1,122 RATED CAPACITY (1,122 MWe) 0 MWe
Current:
0 MWe
Powering 0 homes
Rated Capacity:
1,122 MWe
897,600 homes
14-Day Power History
99
0
0
0
0
0
0
0
0
0
Oct 6 Oct 19

Capacity Factor (365-Day)

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0%
Current
96.2%
365-Day Avg
#44
of 94 plants
Min: 0% Max: 100% 17 days <80%

Outage Days by Year

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Total days spent in outage each year, split by scheduled refueling (blue) and forced/unplanned (red). Lower totals indicate better reliability and outage execution. Hover for details.
Across its recorded history, Diablo Canyon 1 has spent 690 days in scheduled refueling outages and 109 days in forced or unplanned outages. Taller bars mark the years with the most downtime.
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Duration of each outage in days, shown chronologically. Green bars are scheduled refueling outages, red bars are forced/unscheduled. The orange dashed line marks the average duration. Extended outages (>180 days) and D&D periods are excluded.

Outage Duration Trend

Diablo Canyon 1 has 34 outages plotted here, averaging 24 days each. The most recent, in Oct 2026, was a scheduled refueling outage lasting 9 days.
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Scheduled refueling outage durations over time. Green bars are at or below this unit's average, amber up to 30% above it, red beyond that. The dashed line is the average. Shorter outages mean better execution.

Refueling Duration Trend

Diablo Canyon 1 has completed 18 scheduled refueling outages on record, averaging 38 days each. The most recent, in Oct 2026, ran 9 days.
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Time in days from first power generation (>0%) to sustained full power (≥95% for 2+ consecutive days) after each scheduled refueling outage. The dashed line marks the average. Includes startup testing holds and power dips.

Startup Duration Trend

After a refueling outage, Diablo Canyon 1 takes about 8 days to climb from first power back to full power. That average is drawn from 17 startups on record, and the most recent took 5 days.
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Daily reactor power over the 120 days before each scheduled refueling outage, one line per refueling, lined up on the day the outage began. A coastdown is the slow decline as the fuel runs out near the end of a cycle. The highlighted line is the most recent refueling and fainter lines are older. Counts and medians cover coastdowns of a week or longer. A shutdown straight from full power, with no decline ahead of it, is what a forced outage looks like.

Coastdown Before Refueling

4 of 18 refuelings 15 days median 86% power at shutdown 0.9% per day
Diablo Canyon 1 coasted down for a week or longer before 4 of its 18 refuelings on record. Those coastdowns ran a median of 15 days and ended near 86% power. The most recent refueling, in Oct 2026, began with no extended coastdown.
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Monthly capacity factor with outage events overlaid as red bands. Green bars show average power level per month. Toggle to Daily view for raw daily data.

Power History

Over its operating life, Diablo Canyon 1 has run at about 90.2% of its rated capacity. Across the last 12 reported months it averaged 94.6%. On the chart, green stretches near the top are full-power running, amber marks reduced power (50 to 89%), and red drops toward zero are outages.

Outage History & Daily Power Log

This table logs every recorded outage for Diablo Canyon 1, 34 in all since 1999. Of those, 18 were scheduled refueling outages, 1 was planned maintenance and 15 were unplanned or forced. The typical outage lasted about 24 days. Where the Scheduled column shows (Model), the date is a NukeWorker projection because the utility had not published one.
Type ⇅ Actual Start ⇅ Actual End ⇅ Duration ⇅ Days Online ⇅ Scheduled Delta
Scheduled 1R26
2026-10-11 In Outage 9+ 297d 2026-10-12 -1d
Unscheduled
2025-12-17 2025-12-18 2 214d - -
Scheduled 1R25
2025-04-13 2025-05-17 35 484d 2025-04-13 0d
Unscheduled
2023-12-09 2023-12-16 8 27d - -
Scheduled # 56769 Manual 1R24
2023-10-01 2023-11-12 43 528d 2023-10-04 -3d
Scheduled 1R23
2022-03-27 2022-04-21 26 511d 2022-03-27 0d
Scheduled 1R22
2020-10-04 2020-11-01 29 568d 2020-10-04 0d
Scheduled 1R21
2019-02-10 2019-03-16 35 599d 2019-02-10 0d
Unscheduled
2017-06-21 2017-06-21 1 2d - -
Scheduled 1R20
2017-04-23 2017-06-19 58 533d 2017-04-30 -7d
Scheduled 1R19
2015-10-04 2015-11-07 35 273d 2015-09-27 +7d
Unscheduled
2015-01-01 2015-01-04 4 281d - -
Unscheduled
2014-03-17 2014-03-26 10 5d - -
Scheduled 1R18
2014-02-09 2014-03-12 32 223d 2014-02-09 0d
Unscheduled
2013-06-27 2013-07-01 5 377d - -
Scheduled 1R17
2012-04-23 2012-06-15 54 530d 2012-04-22 +1d
Scheduled 1R16
2010-10-03 2010-11-10 39 377d 2010-10-04 -1d
Unscheduled
2009-09-20 2009-09-21 2 181d - -
Scheduled 1R15
2009-01-26 2009-03-23 57 530d 2009-01-26 0d
Unscheduled
2007-08-11 2007-08-15 5 75d - -
Scheduled 1R14
2007-05-01 2007-05-28 28 518d 2007-04-30 +1d
Scheduled 1R13
2005-10-24 2005-11-29 37 458d 2005-10-23 +1d
Unscheduled
2004-07-22 2004-07-23 2 49d - -
Scheduled 1R12SGR/Major
2004-03-23 2004-06-03 73 468d 2004-04-23 -31d
Planned Mid-Cycle Planned
2002-10-21 2002-12-11 52 139d - -
Unscheduled
2002-06-04 2002-06-04 1 9d - -
Scheduled 1R11
2002-04-29 2002-05-26 28 524d 2002-04-08 (Model) +21d (Model)
Unscheduled
2000-11-21 2000-11-21 1 8d - -
Scheduled 1R10
2000-10-08 2000-11-13 37 135d 2000-10-08 0d
Unscheduled
2000-05-15 2000-05-26 12 177d - -
Unscheduled
1999-11-20 1999-11-20 1 21d - -
Unscheduled
1999-10-29 1999-10-30 2 36d - -
Unscheduled
1999-09-23 1999-09-23 1 193d - -
Scheduled 1R9
1999-02-08 1999-03-14 35 - 1999-02-08 0d
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