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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.
48
Excellence
#50 of 94 ↑7
Mid Quartile
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Days of continuous operation since the last outage ended. Clean run (no forced outages since last refueling).
197
Current Run
days ✔
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Longest recorded period of continuous operation between outages (2009-05-06 to 2010-10-11).
523
Record Run
days
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (454 days for this 18-month cycle 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).
90.6%
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.
5.7
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.
99.3%
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
48/100
Mid Quartile · #50/94
5-year window
Farley 1 ranks #50 of 94 active US units on NukeWorker's Operational Excellence Score over the 5-year window. Strongest area: Forced Outage Days/yr (75th percentile). Weakest: Startup Duration (15th percentile).
Reliability
47
Capacity factor + Forced outages + B2B streaks
Efficiency
66
Fuel utilization + Refuel duration
Discipline
31
Startup duration + Scram count
Cohort Rankings
apples-to-apples comparison within each peer group
Reactor type:
#34 of 61
PWR
Containment:
#30 of 48
Dry Ambient (PWR)
Cycle length:
#27 of 54
18-month cycle
Fleet rank above (50 of 94) compares all active US units; cohort ranks compare only against units sharing this property.
Per-dimension breakdown (7 metrics)
Capacity Factor
45th
90.3% (higher better, Reliability)
Forced Outage Days/yr
75th
1.8d (lower better, Reliability)
B2B Avg Streak
20th
501d (higher better, Reliability)
Fuel Utilization
75th
98.6% (higher better, Efficiency)
Refuel Duration
57th
31d (lower better, Efficiency)
Startup Duration
15th
7.5d (lower better, Discipline)
Scrams (5-year)
48th
0.4/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:
↑ +2.9 pts vs 2025
Compare Farley 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
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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 Oct 29, 2025
61.5% remaining
196 / 505 days
1.7 FPD margin
Avg refuel: 2.1%
Avg refuel (3yr): 0.7%
Deepest burn: 0.0% (2003-05 → 2004-10)
Most margin: 8.0% (2022-12 → 2024-04)
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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 |
|---|---|---|---|---|---|---|
|
Unscheduled
Startup Hold
|
2025-10-29 | 2025-10-29 | 1 | 5d | - | - |
|
Scheduled
|
2025-09-29 | 2025-10-24 | 26 | 508d | 2025-09-17 | +12d |
|
Scheduled
|
2024-04-08 | 2024-05-09 | 32 | 429d | 2024-04-05 | +3d |
|
Scram
# 56329
|
2023-02-02 | 2023-02-04 | 3 | 43d | - | - |
|
Scheduled
SGR/Major
|
2022-09-19 | 2022-12-21 | 94 | 45d | 2022-09-18 | +1d |
|
Scram
# 56028
|
2022-08-04 | 2022-08-05 | 2 | 468d | - | - |
|
Scram
# 55206
|
2021-04-23 | 2021-04-23 | 1 | 6d | - | - |
|
Scheduled
|
2021-03-22 | 2021-04-17 | 27 | 516d | 2021-03-22 | 0d |
|
Scheduled
|
2019-09-30 | 2019-10-23 | 24 | 217d | 2019-09-29 | +1d |
|
Unscheduled
|
2019-02-20 | 2019-02-25 | 6 | 145d | - | - |
|
Unscheduled
|
2018-09-25 | 2018-09-28 | 4 | 138d | - | - |
|
Scheduled
|
2018-04-09 | 2018-05-10 | 32 | 8d | 2018-04-01 | +8d |
|
Unscheduled
|
2018-03-27 | 2018-04-01 | 6 | 484d | - | - |
|
Scram
# 52395
|
2016-11-27 | 2016-11-28 | 2 | 9d | - | - |
|
Unscheduled
|
2016-11-18 | 2016-11-18 | 1 | 5d | - | - |
|
Scram
# 52356
|
2016-11-09 | 2016-11-13 | 5 | 4d | - | - |
|
Scheduled
|
2016-10-02 | 2016-11-05 | 35 | 491d | 2016-09-24 | +8d |
|
Unscheduled
|
2015-05-27 | 2015-05-30 | 4 | 19d | - | - |
|
Unscheduled
|
2015-05-08 | 2015-05-08 | 1 | 4d | - | - |
|
Scheduled
|
2015-03-30 | 2015-05-04 | 36 | 521d | 2015-03-29 | +1d |
|
Scheduled
|
2013-09-30 | 2013-10-25 | 26 | 109d | 2013-10-06 | -6d |
|
Scram
# 49106
|
2013-06-12 | 2013-06-13 | 2 | 318d | - | - |
|
Unscheduled
|
2012-07-27 | 2012-07-29 | 3 | 93d | - | - |
|
Scheduled
|
2012-04-02 | 2012-04-25 | 24 | 73d | 2012-03-25 | +8d |
|
Unscheduled
|
2012-01-17 | 2012-01-20 | 4 | 425d | - | - |
|
Scheduled
|
2010-10-11 | 2010-11-18 | 39 | 523d | 2010-10-02 | +9d |
|
Scheduled
|
2009-04-03 | 2009-05-06 | 34 | 134d | 2009-03-28 | +6d |
|
Unscheduled
|
2008-11-20 | 2008-11-20 | 1 | 114d | - | - |
|
Unscheduled
|
2008-07-23 | 2008-07-29 | 7 | 254d | - | - |
|
Scheduled
|
2007-09-29 | 2007-11-12 | 45 | 455d | 2007-09-29 | 0d |
|
Unscheduled
|
2006-07-01 | 2006-07-01 | 1 | 39d | - | - |
|
Scheduled
|
2006-04-08 | 2006-05-23 | 46 | 292d | 2006-04-07 | +1d |
|
Unscheduled
|
2005-06-19 | 2005-06-20 | 2 | 216d | - | - |
|
Scheduled
|
2004-10-02 | 2004-11-15 | 45 | 214d | 2004-10-01 | +1d |
|
Unscheduled
|
2004-03-02 | 2004-03-02 | 1 | 307d | - | - |
|
Scheduled
|
2003-03-29 | 2003-04-30 | 33 | 108d | 2003-03-29 | 0d |
|
Unscheduled
|
2002-12-11 | 2002-12-11 | 1 | 55d | - | - |
|
Unscheduled
|
2002-10-16 | 2002-10-17 | 2 | 165d | - | - |
|
Unscheduled
|
2002-05-04 | 2002-05-04 | 1 | 171d | - | - |
|
Scheduled
|
2001-10-06 | 2001-11-14 | 40 | 500d | 2001-10-06 | 0d |
|
Scheduled
SGR/Major
|
2000-03-04 | 2000-05-24 | 82 | 281d | 2000-03-04 | 0d |
|
Unscheduled
|
1999-05-28 | 1999-05-28 | 1 | - | - | - |
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