Millstone 3

Refueling Outage · Day 5

Dominion Energy·Waterford, CT·PWR·1,243 MWe

Data refreshed 6.9h ago Rx Status: Oct 16, 2026 at 9:02 AM (M-F)

Outage History Daily Power Log Get alerts

Reactor Status Timeline

Refueling Outage · Day 5 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.
Nov2025DecJan2026FebMarAprMayJunJulAugSepOctOnline: Oct 16, 2025Forced Outage: Oct 17, 2025 to Oct 26, 2025Power Ascension: Oct 27, 2025 to Oct 28, 2025Online: Oct 29, 2025 to Nov 3, 2025Power Ascension: Nov 4, 2025Reduced Power: Nov 5, 2025Online: Nov 6, 2025 to Oct 11, 2026Refueling Outage (3R24): Oct 12, 2026 to Oct 16, 2026Today
OnlineReduced PowerPower AscensionRefueling 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 2026-10-16). 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 (1999-06-27 to 2001-02-03).
587
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.
7
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.
16.91 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.
7
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.
94.9%
Fuel Utilization
3yr avg

Reactor Status

Current Reactor Status Oct 16, 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.
Millstone 3 is OFFLINE (5 Days) at 0% of rated power as of Oct 16, 2026. This outage is RFO 3R24. Over the last 14 reported days it has run between 0% and 100% power.
Millstone 3 is OFFLINE (5 Days) Get alerts
0
PERCENT
0 200 400 600 800 1000 1200 1,243 RATED CAPACITY (1,243 MWe) 0 MWe
Current:
0 MWe
Powering 0 homes
Rated Capacity:
1,243 MWe
994,400 homes
14-Day Power History
0
0
0
0
0
Oct 3 Oct 16

Capacity Factor (365-Day)

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0%
Current
95.5%
365-Day Avg
#20
of 94 plants
Min: 0% Max: 100% 19 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, Millstone 3 has spent 660 days in scheduled refueling outages and 226 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

Millstone 3 has 42 outages plotted here, averaging 21 days each. The most recent, in Oct 2026, was a scheduled refueling outage lasting 5 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

Millstone 3 has completed 18 scheduled refueling outages on record, averaging 37 days each. The most recent, in Oct 2026, ran 5 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, Millstone 3 takes about 4 days to climb from first power back to full power. That average is drawn from 17 startups on record, and the most recent took 4 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 21 days median 88% power at shutdown 0.5% per day
Millstone 3 coasted down for a week or longer before 4 of its 18 refuelings on record. Those coastdowns ran a median of 21 days and ended near 88% 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, Millstone 3 has run at about 90.2% of its rated capacity. Across the last 12 reported months it averaged 97.3%. 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 Millstone 3, 42 in all since 1999. Of those, 18 were scheduled refueling outages and 24 were unplanned or forced. The typical outage lasted about 21 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 3R24
2026-10-12 In Outage 5+ 351d 2026-10-11 +1d
Unscheduled
2025-10-17 2025-10-26 10 75d - -
Unscheduled
2025-08-01 2025-08-03 3 76d - -
Scheduled 3R23
2025-04-11 2025-05-17 37 207d 2025-04-13 -2d
Unscheduled
2024-09-04 2024-09-16 13 231d - -
Unscheduled
2024-01-09 2024-01-17 9 32d - -
Unscheduled
2023-12-03 2023-12-08 6 3d - -
Scheduled 3R22
2023-10-20 2023-11-30 42 114d 2023-10-14 +6d
Scram # 56544 Auto
2023-05-31 2023-06-28 29 363d - -
Scheduled 3R21
2022-04-08 2022-06-02 56 295d 2022-04-07 +1d
Unscheduled
2021-06-11 2021-06-17 7 159d - -
Unscheduled
2020-12-31 2021-01-03 4 50d - -
Scheduled 3R20
2020-10-02 2020-11-11 41 171d 2020-10-19 -17d
Scram # 54663 Auto
2020-04-14 2020-04-14 1 4d - -
Scram # 54631 Auto
2020-04-02 2020-04-10 9 102d - -
Unscheduled
2019-12-18 2019-12-22 5 218d - -
Scheduled 3R19
2019-04-12 2019-05-14 33 515d 2019-04-13 -1d
Scheduled 3R18
2017-10-13 2017-11-13 32 477d 2017-10-08 +5d
Scram # 52000 Manual
2016-06-13 2016-06-23 11 27d - -
Scram # 51929 Manual
2016-05-16 2016-05-17 2 4d - -
Scheduled 3R17
2016-04-10 2016-05-12 33 73d 2016-04-10 0d
Scram # 51682 Auto
2016-01-25 2016-01-28 4 435d - -
Scheduled 3R16
2014-10-12 2014-11-16 36 132d 2014-10-12 0d
Scram # 50141 Auto
2014-05-26 2014-06-02 8 286d - -
Scram # 49260 Auto
2013-08-10 2013-08-13 4 85d - -
Scheduled 3R15
2013-04-14 2013-05-17 34 509d 2013-04-14 0d
Scheduled 3R14
2011-10-09 2011-11-22 45 419d 2011-10-09 0d
Unscheduled
2010-08-15 2010-08-16 2 89d - -
Unscheduled
2010-05-18 2010-05-18 1 2d - -
Scheduled 3R13
2010-04-11 2010-05-16 36 96d 2010-04-04 +7d
Unscheduled
2009-12-20 2010-01-05 17 392d - -
Scheduled 3R12
2008-10-12 2008-11-23 43 513d 2008-10-12 0d
Scheduled 3R11
2007-04-07 2007-05-18 42 68d 2007-04-07 0d
Unscheduled
2007-01-29 2007-01-29 1 421d - -
Unscheduled
2005-12-02 2005-12-04 3 36d - -
Scheduled 3R10
2005-09-30 2005-10-27 28 153d 2005-09-29 +1d
Unscheduled
2005-04-18 2005-04-30 13 347d - -
Scheduled 3R9
2004-04-03 2004-05-06 34 461d 2004-04-02 +1d
Unscheduled
2002-12-23 2002-12-29 7 80d - -
Scheduled 3R8
2002-09-07 2002-10-04 28 527d 2002-09-07 0d
Scheduled 3R7
2001-02-03 2001-03-29 55 587d 2001-02-03 0d
Unscheduled
1999-05-02 1999-06-27 57 - - -
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