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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.
70
Excellence
#21 of 94 ↑1
Top Quartile
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Days of continuous operation since the last outage ended. Clean run (no forced outages since last refueling).
404
Current Run
days ✔
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Longest recorded period of continuous operation between outages (2010-04-06 to 2011-09-19).
531
Record Run
days
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (463 days for this 18-month cycle unit) with no trips to 0% power.
8
B2B Runs
86% toward B2B (400/463d)
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Lifetime capacity factor: average power level across all recorded days (100% = always at full power).
92.3%
Capacity Factor
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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.
2.7
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.
97.4%
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 publicly observable 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.
• 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
NukeWorker's
Operational
Excellence Score
Operational
Excellence Score
70/100
Top Quartile · #21/94
5-year window
Vogtle 2 ranks #21 of 94 active US units on NukeWorker's Operational Excellence Score over the 5-year window. Strongest area: Scrams (5-year) (90th percentile). Weakest: B2B Avg Streak (22th percentile).
Reliability
66
Capacity factor + Forced outages + B2B streaks
Efficiency
63
Fuel utilization + Refuel duration
Discipline
81
Startup duration + Scram count
Cohort Rankings
apples-to-apples comparison within each peer group
Reactor type:
#12 of 61
PWR
Containment:
#10 of 48
Dry Ambient (PWR)
Cycle length:
#9 of 54
18-month cycle
Fleet rank above (21 of 94) compares all active US units; cohort ranks compare only against units sharing this property.
Per-dimension breakdown (7 metrics)
Capacity Factor
89th
95.4% (higher better, Reliability)
Forced Outage Days/yr
87th
1.0d (lower better, Reliability)
B2B Avg Streak
22th
502d (higher better, Reliability)
Fuel Utilization
53th
98.1% (higher better, Efficiency)
Refuel Duration
72th
26d (lower better, Efficiency)
Startup Duration
71th
3.6d (lower better, Discipline)
Scrams (5-year)
90th
0.0/yr (lower better, Discipline)
Each dimension's percentile is computed across the active US fleet (94 units with sufficient history). Sub-score = average of its component percentiles. Composite = average of the three sub-scores. 5-year window. View full leaderboard →
Methodology
NukeWorker's Operational Excellence Score is a composite ranking that combines 7 publicly observable performance metrics into a single 0-100 number per US nuclear unit.
How it's computed: Each unit's raw value is converted to a percentile (0-100) within the 94 active US units that have at least 2 completed refueling cycles. The 7 percentiles are averaged into 3 sub-scores (Reliability, Efficiency, Discipline), and those are averaged into the final composite.
Active window — 5-year:
- Reliability — Capacity factor (5yr), forced outage days/yr (5yr), B2B avg streak (lifetime)
- Efficiency — in-cycle fuel utilization (3yr), median refuel duration (5yr)
- Discipline — robust mean startup duration, scrams/yr (5yr, annualised)
Cohort rankings: alongside the fleet rank, each unit gets ranked within its reactor type (PWR/BWR), containment design (Ice Condenser, Mark I, etc.), and cycle length (12/18/24-month). Useful for apples-to-apples comparisons.
What's excluded: subjective community ratings, confidential INPO ratings, financial metrics. We only use publicly available NRC + cycle data.
Why three windows? 5yr (default) is the industry standard. 3yr captures recent operational changes and post-pandemic recovery. Lifetime gives newer units a fair comparison and reveals long-term consistency.
Edge cases: units with fewer than 2 cycles (e.g., Vogtle 4) show "Provisional". Decommissioned units excluded.
Refresh cadence: recomputed daily. Each window cached separately.
A data-derived proxy for operational performance; not affiliated with INPO. INPO ratings are confidential and qualitative — ours is public and quantitative.
5-yr trend:
↑ +2.2 pts vs 2025
Compare Vogtle 2 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
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Days between consecutive scheduled refueling outage starts, showing operating cycle regularity. The purple dashed line marks the average cycle length. Most U.S. reactors operate on 18-month (547 day) or 24-month (730 day) cycles.
Cycle Length History
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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
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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 Apr 2, 2025
23.2% remaining
401 / 521 days
1.0 FPD margin
Avg refuel: 3.9%
Avg refuel (3yr): 2.6%
Deepest burn: 0.0% (2010-04 → 2011-09)
Most margin: 11.6% (2004-05 → 2005-09)
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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
| Type ⇅ | Actual Start ⇅ | Actual End ⇅ | Duration ⇅ | Days Online ⇅ | Scheduled | Delta |
|---|---|---|---|---|---|---|
|
Scheduled
|
2025-03-06 | 2025-04-01 | 27 | 257d | 2025-03-06 | 0d |
|
Unscheduled
|
2024-06-21 | 2024-06-22 | 2 | 265d | - | - |
|
Scheduled
|
2023-09-10 | 2023-09-30 | 21 | 523d | 2023-09-11 | -1d |
|
Scheduled
|
2022-03-06 | 2022-04-05 | 31 | 474d | 2022-03-06 | 0d |
|
Scram
# 54995
|
2020-11-13 | 2020-11-17 | 5 | 63d | - | - |
|
Scheduled
|
2020-08-17 | 2020-09-11 | 26 | 54d | 2020-09-20 | -34d |
|
Unscheduled
|
2020-06-22 | 2020-06-24 | 3 | 336d | - | - |
|
Scram
# 54175
|
2019-07-20 | 2019-07-22 | 3 | 110d | - | - |
|
Scram
# 53967
|
2019-03-31 | 2019-04-01 | 2 | 3d | - | - |
|
Scheduled
|
2019-03-11 | 2019-03-28 | 18 | 524d | 2019-03-10 | +1d |
|
Scheduled
|
2017-09-18 | 2017-10-03 | 16 | 481d | 2017-09-17 | +1d |
|
Scram
# 51956
|
2016-05-25 | 2016-05-25 | 1 | 59d | - | - |
|
Scheduled
|
2016-03-07 | 2016-03-27 | 21 | 357d | 2016-03-06 | +1d |
|
Scram
# 50893
|
2015-03-14 | 2015-03-16 | 3 | 152d | - | - |
|
Scheduled
|
2014-09-15 | 2014-10-13 | 29 | 159d | 2014-09-14 | +1d |
|
Scram
# 50006
|
2014-04-08 | 2014-04-09 | 2 | 167d | - | - |
|
Scram
# 49461
|
2013-10-23 | 2013-10-23 | 1 | 3d | - | - |
|
Scram
# 49461
|
2013-10-20 | 2013-10-20 | 1 | 135d | - | - |
|
Unscheduled
|
2013-06-02 | 2013-06-07 | 6 | 61d | - | - |
|
Scheduled
|
2013-03-11 | 2013-04-02 | 23 | 11d | 2013-03-10 | +1d |
|
Scram
# 48788
|
2013-02-27 | 2013-02-28 | 2 | 505d | - | - |
|
Scheduled
|
2011-09-19 | 2011-10-11 | 23 | 531d | 2011-09-18 | +1d |
|
Scheduled
|
2010-03-08 | 2010-04-06 | 30 | 74d | 2010-03-07 | +1d |
|
Unscheduled
|
2009-12-24 | 2009-12-24 | 1 | 398d | - | - |
|
Unscheduled
|
2008-11-17 | 2008-11-21 | 5 | 29d | - | - |
|
Scheduled
|
2008-09-15 | 2008-10-19 | 35 | 503d | 2008-09-14 | +1d |
|
Unscheduled
|
2007-04-24 | 2007-05-01 | 8 | 3d | - | - |
|
Scheduled
|
2007-03-04 | 2007-04-21 | 49 | 184d | 2007-03-03 | +1d |
|
Unscheduled
|
2006-08-28 | 2006-09-01 | 5 | 149d | - | - |
|
Unscheduled
|
2006-03-21 | 2006-04-01 | 12 | 35d | - | - |
|
Unscheduled
|
2006-02-04 | 2006-02-14 | 11 | 48d | - | - |
|
Unscheduled
|
2005-12-10 | 2005-12-18 | 9 | 57d | - | - |
|
Scheduled
|
2005-09-18 | 2005-10-14 | 27 | 102d | 2005-09-17 | +1d |
|
Unscheduled
|
2005-05-24 | 2005-06-08 | 16 | 184d | - | - |
|
Unscheduled
|
2004-11-21 | 2004-11-21 | 1 | 106d | - | - |
|
Unscheduled
|
2004-08-07 | 2004-08-07 | 1 | 83d | - | - |
|
Scheduled
|
2004-04-18 | 2004-05-16 | 29 | 228d | 2004-04-18 | 0d |
|
Unscheduled
|
2003-08-31 | 2003-09-03 | 4 | 16d | - | - |
|
Unscheduled
|
2003-08-09 | 2003-08-15 | 7 | 139d | - | - |
|
Unscheduled
|
2003-03-23 | 2003-03-23 | 1 | 102d | - | - |
|
Unscheduled
|
2002-11-25 | 2002-12-11 | 17 | 10d | - | - |
|
Scheduled
|
2002-10-06 | 2002-11-15 | 41 | 520d | 2002-11-25 | -50d |
|
Scheduled
|
2001-04-08 | 2001-05-04 | 27 | 465d | 2001-04-08 | 0d |
|
Unscheduled
|
1999-12-28 | 1999-12-30 | 3 | 55d | - | - |
|
Scheduled
|
1999-10-04 | 1999-11-03 | 31 | 216d | 1999-10-04 | 0d |
|
Unscheduled
|
1999-03-02 | 1999-03-02 | 1 | - | - | - |
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