Davis-Besse - Status & History

Comprehensive reactor performance metrics, cycle analysis, and historical outage data.

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Reactor Status Timeline

Online 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.
Oct2025NovDecJan2026FebMarAprMayJunJulAugSepOnline: Sep 7, 2025 to Feb 20, 2026Coastdown: Feb 21, 2026 to Feb 28, 2026Refueling Outage (1R24): Mar 1, 2026 to Mar 30, 20261R24Power Ascension: Mar 31, 2026 to Apr 1, 2026Online: Apr 2, 2026 to Sep 7, 2026Today
OnlineCoastdownPower AscensionRefueling 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
ranked of 93
Subscribers
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Days of continuous operation since the last outage ended. Clean run (no forced outages since last refueling).
161
Current Run
days ✔
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Longest recorded period of continuous operation between outages (2000-05-18 to 2002-02-16).
639
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.
1
B2B Runs
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Lifetime capacity factor: average power level across all recorded days (100% = always at full power).
83.6%
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). Authoritative actuals, not an estimate.
7.08 TWh
Net Generation
EIA-923 · 12 mo to 2026-06
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Total number of scheduled refueling outages detected in the historical data.
12
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.
2
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.
98.9%
Fuel Utilization
3yr avg
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NukeWorker's Operational Excellence Score is a composite 0–100 ranking of every active US nuclear unit across 7 measured performance metrics, grouped into three sub-scores:
• Reliability — capacity factor, forced outage days, B2B avg streak
• Efficiency — fuel utilization, refuel duration
• Discipline — startup duration, scram count
Each unit's metric is converted to a percentile across the active fleet. Sub-score = average of its components; composite = average of the three sub-scores. Use the time-window toggle below to switch between 3yr / 5yr / lifetime.
Time window — change how far back we look
5-yr trend: 2021: 55/100 (#45/93)2022: 50/100 (#50/92)2023: 31/100 (#75/92)2024: 60/100 (#27/92)2025: 45/100 (#58/92)2026: 70/100 (#23/93) ↑ +25.0 pts vs 2025
Compare Davis-Besse head-to-head with up to 3 other units. Compare now
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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

Davis-Besse has 32 outages plotted here, averaging 25 days each. The most recent, in Mar 2026, was a scheduled refueling outage lasting 30 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, Davis-Besse takes about 3 days to climb from first power back to full power. That average is drawn from 13 startups on record, and the most recent took 2 days.
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Estimated fuel remaining in the current cycle, expressed as a percentage of the unit's typical cycle. Starts at 100% when the unit returns to power post-refuel and drops as full-power-days are burned. Days at reduced power burn fuel proportionally — so a unit with significant downtime (high burn deficit) drops slower and ends up with MORE fuel left than its calendar position would suggest. Coastdown threshold around 15%. Toggle to overlay past cycles on a normalized "days into cycle" axis to see how aggressively this unit historically burns down before refuel.

Fuel Burn Down Cycle since Mar 31, 2026

77.7% remaining 0.4 FPD margin
Davis-Besse has an estimated 77.7% of its fuel left. Across its last 12 cycles, it has refueled with an average of 6.9% remaining.
Avg refuel: 6.9% Avg refuel (3yr): 1.1% Deepest burn: 0.0% (2008-02 → 2010-02) Most margin: 17.1% (2012-06 → 2014-02)
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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, Davis-Besse has run at about 83.6% of its rated capacity. Across the last 12 reported months it averaged 91.5%. On the chart, flat stretches near the top are full-power running and drops to zero are outages.
This table logs every recorded outage for Davis-Besse, 33 in all since 1999. Of those, 13 were scheduled refueling outages, 1 was planned maintenance and 19 were unplanned or forced. The typical outage lasted about 47 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 1R24
2026-03-01 2026-03-30 30 195d 2026-02-28 +1d
Unscheduled
2025-08-13 2025-08-18 6 503d - -
Scheduled 1R23
2024-03-03 2024-03-28 26 442d 2024-03-01 +2d
Unscheduled
2022-12-05 2022-12-17 13 231d - -
Scheduled 1R22
2022-03-05 2022-04-18 45 237d 2022-03-05 0d
Scram # 55346
2021-07-09 2021-07-11 3 470d - -
Scheduled 1R21
2020-02-29 2020-03-26 27 172d 2020-02-29 0d
Scram # 54263
2019-09-08 2019-09-10 3 237d - -
Unscheduled
2019-01-13 2019-01-14 2 293d - -
Scheduled 1R20
2018-03-03 2018-03-26 24 529d 2018-03-03 0d
Scram # 52232
2016-09-10 2016-09-20 11 124d - -
Scheduled 1R19
2016-03-26 2016-05-09 45 55d 2016-03-26 0d
Scram # 51696
2016-01-30 2016-01-31 2 264d - -
Scram # 51061
2015-05-10 2015-05-11 2 369d - -
Scheduled 1R18SGR/Major
2014-02-01 2014-05-06 95 205d 2014-02-06 -5d
Scram # 49159
2013-06-30 2013-07-11 12 383d - -
Scheduled 1R17
2012-05-06 2012-06-12 38 153d 2012-05-01 +5d
Unscheduled
2011-10-01 2011-12-05 66 261d - -
Unscheduled
2011-01-09 2011-01-13 5 195d - -
Scheduled 1R16SGR/Major
2010-02-28 2010-06-28 121 314d 2010-02-28 0d
Unscheduled
2009-04-05 2009-04-20 16 417d - -
Unscheduled
2008-02-06 2008-02-13 8 6d - -
Scheduled 1R15
2007-12-30 2008-01-31 33 401d 2007-12-28 +2d
Unscheduled
2006-11-18 2006-11-24 7 72d - -
Unscheduled
2006-09-06 2006-09-07 2 133d - -
Scheduled 1R14
2006-03-06 2006-04-26 52 127d 2006-03-05 +1d
Unscheduled
2005-10-29 2005-10-30 2 262d - -
Planned Mid-Cycle Planned
2005-01-18 2005-02-09 23 164d - -
Unscheduled
2004-08-05 2004-08-07 3 132d - -
Unscheduled
2004-03-18 2004-03-26 9 4d - -
Scheduled 1R13Ext. Shutdown
2002-02-16 2004-03-14 758 639d 2002-02-16 0d
Scheduled 1R12
2000-04-01 2000-05-18 48 327d 2000-04-01 0d
Unscheduled
1999-04-24 1999-05-10 17 - - -
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