Oconee 1 - Status & History

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

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 12, 2025 to Sep 12, 2026Today
Online
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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).
669
Current Run
days ✔
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Longest recorded period of continuous operation between outages (2020-11-17 to 2022-10-29).
711
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.
4
B2B Runs
Active: 667 days
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Lifetime capacity factor: average power level across all recorded days (100% = always at full power).
90.9%
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.
21.95 TWh
Net Generation
EIA-923 · 12 mo to 2026-06 · plant total
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Total number of scheduled refueling outages detected in the historical data.
16
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.
1.3
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.
79.6%
Fuel Utilization
lifetime 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: 53/100 (#51/93)2022: 65/100 (#25/92)2023: 77/100 (#14/92)2024: 84/100 (#9/92)2025: 85/100 (#9/92)2026: 85/100 (#6/93) Stable vs 2025
Compare Oconee 1 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

Oconee 1 has 33 outages plotted here, averaging 25 days each. The most recent, in Oct 2024, was a scheduled refueling outage lasting 22 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, Oconee 1 takes about 3 days to climb from first power back to full power. That average is drawn from 16 startups on record, and the most recent took 1 day.
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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 Nov 13, 2024

4.9% remaining 0.0 FPD margin
Oconee 1 has an estimated 4.9% of its fuel left. Across its last 15 cycles, it has refueled with an average of 20.4% remaining.
Avg refuel: 20.4% Deepest burn: 0.0% (2020-11 → 2022-10) Most margin: 40.1% (2001-01 → 2002-03)
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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, Oconee 1 has run at about 90.9% of its rated capacity. Across the last 12 reported months it averaged 100.0%. 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 Oconee 1, 33 in all since 1999. Of those, 16 were scheduled refueling outages and 17 were unplanned or forced. The typical outage lasted about 25 days. Where the Scheduled column shows (Model), the date is a NukeWorker projection because the utility had not published one.
Scheduled 1EOC33
2024-10-22 2024-11-12 22 698d 2024-10-19 +3d
Scheduled 1EOC32
2022-10-29 2022-11-24 27 711d 2022-10-29 0d
Scheduled 1EOC31
2020-10-17 2020-11-17 32 679d 2020-10-24 -7d
Unscheduled
2018-12-01 2018-12-08 8 17d - -
Scheduled # 53677 1EOC30
2018-10-20 2018-11-14 26 189d 2018-10-13 +7d
Scram # 53329
2018-04-13 2018-04-14 2 413d - -
Unscheduled
2017-02-18 2017-02-24 7 84d - -
Scheduled 1EOC29
2016-11-05 2016-11-26 22 222d 2016-10-31 +5d
Scram # 51770
2016-03-07 2016-03-28 22 456d - -
Scheduled 1EOC28
2014-11-04 2014-12-07 34 338d 2014-11-01 +3d
Unscheduled
2013-11-12 2013-12-01 20 348d - -
Scheduled 1EOC27
2012-10-27 2012-11-29 34 101d 2012-10-27 0d
Unscheduled
2012-07-18 2012-07-18 1 405d - -
Scheduled 1EOC26
2011-04-02 2011-06-09 69 76d 2011-04-02 0d
Unscheduled
2011-01-09 2011-01-16 8 154d - -
Unscheduled
2010-08-08 2010-08-08 1 249d - -
Scheduled 1EOC25
2009-10-10 2009-12-02 54 37d 2009-10-10 0d
Unscheduled
2009-09-02 2009-09-03 2 459d - -
Scheduled 1EOC24
2008-04-12 2008-05-31 50 414d 2008-04-12 0d
Unscheduled
2007-02-16 2007-02-23 8 65d - -
Scheduled 1EOC23
2006-10-07 2006-12-13 68 109d 2006-10-06 +1d
Unscheduled
2006-06-14 2006-06-20 7 395d - -
Scheduled 1EOC22
2005-04-09 2005-05-15 37 455d 2005-04-08 +1d
Unscheduled
2004-01-09 2004-01-10 2 6d - -
Unscheduled
2003-12-18 2004-01-03 17 2d - -
Scheduled 1EOC21SGR/Major
2003-09-20 2003-12-16 88 400d 2003-09-20 0d
Unscheduled
2002-08-16 2002-08-16 1 110d - -
Scheduled 1EOC20
2002-03-23 2002-04-28 37 189d 2002-03-23 0d
Unscheduled
2001-09-13 2001-09-15 3 245d - -
Scheduled 1EOC19
2000-11-23 2001-01-11 50 265d 2000-11-23 0d
Unscheduled
2000-02-17 2000-03-03 16 180d - -
Unscheduled
1999-08-19 1999-08-21 3 42d - -
Scheduled 1EOC18
1999-05-20 1999-07-08 50 - 1999-05-20 0d
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