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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.
61
Excellence
#31 of 94 ↓21
Mid Quartile
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Days of continuous operation since the last outage ended. Clean run (no forced outages since last refueling).
405
Current Run
days ✔
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Longest recorded period of continuous operation between outages (2021-04-09 to 2023-03-13).
703
Record Run
days
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (627 days for this 24-month cycle unit) with no trips to 0% power.
3
B2B Runs
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Lifetime capacity factor: average power level across all recorded days (100% = always at full power).
91.5%
Capacity Factor
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Total number of scheduled refueling outages detected in the historical data.
14
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
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.
97.2%
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
61/100
Mid Quartile · #31/94
5-year window
Nine Mile Point 1 ranks #31 of 94 active US units on NukeWorker's Operational Excellence Score over the 5-year window. Strongest area: Forced Outage Days/yr (98th percentile). Weakest: Fuel Utilization (24th percentile).
Reliability
88
Capacity factor + Forced outages + B2B streaks
Efficiency
25
Fuel utilization + Refuel duration
Discipline
71
Startup duration + Scram count
Cohort Rankings
apples-to-apples comparison within each peer group
Reactor type:
#12 of 31
BWR
Containment:
#8 of 19
Mark I (BWR)
Cycle length:
#17 of 40
24-month cycle
Fleet rank above (31 of 94) compares all active US units; cohort ranks compare only against units sharing this property.
Per-dimension breakdown (7 metrics)
Capacity Factor
84th
94.9% (higher better, Reliability)
Forced Outage Days/yr
98th
0.4d (lower better, Reliability)
B2B Avg Streak
81th
695d (higher better, Reliability)
Fuel Utilization
24th
96.8% (higher better, Efficiency)
Refuel Duration
26th
37d (lower better, Efficiency)
Startup Duration
51th
4.2d (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:
↓ -21.5 pts vs 2025
Compare Nine Mile Point 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 Apr 5, 2025
42.3% remaining
403 / 695 days
2.2 FPD margin
Avg refuel: 4.5%
Avg refuel (3yr): 2.8%
Deepest burn: 0.0% (2017-04 → 2019-03)
Most margin: 22.4% (1999-06 → 2001-03)
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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
| Type ⇅ | Actual Start ⇅ | Actual End ⇅ | Duration ⇅ | Days Online ⇅ | Scheduled | Delta |
|---|---|---|---|---|---|---|
|
Scheduled
|
2025-03-17 | 2025-04-04 | 19 | 698d | 2025-03-17 | 0d |
|
Scheduled
|
2023-03-13 | 2023-04-19 | 38 | 703d | 2023-03-13 | 0d |
|
Scheduled
|
2021-03-22 | 2021-04-09 | 19 | 687d | 2021-03-22 | 0d |
|
Scram
# 54035
|
2019-04-30 | 2019-05-05 | 6 | 4d | - | - |
|
Unscheduled
|
2019-04-17 | 2019-04-26 | 10 | 3d | - | - |
|
Scram
# 53998
|
2019-04-14 | 2019-04-14 | 1 | 2d | - | - |
|
Scheduled
|
2019-03-18 | 2019-04-12 | 26 | 364d | 2019-03-18 | 0d |
|
Unscheduled
|
2018-03-18 | 2018-03-19 | 2 | 191d | - | - |
|
Scram
# 52950
|
2017-09-07 | 2017-09-08 | 2 | 155d | - | - |
|
Scheduled
|
2017-03-20 | 2017-04-05 | 17 | 98d | 2017-03-15 | +5d |
|
Scram
# 52425
|
2016-12-11 | 2016-12-12 | 2 | 462d | - | - |
|
Scram
# 51369
|
2015-09-05 | 2015-09-06 | 2 | 149d | - | - |
|
Scheduled
|
2015-03-16 | 2015-04-09 | 25 | 614d | 2015-03-16 | 0d |
|
Unscheduled
|
2013-07-09 | 2013-07-10 | 2 | 57d | - | - |
|
Scheduled
|
2013-04-15 | 2013-05-13 | 29 | 117d | 2013-04-01 | +14d |
|
Unscheduled
|
2012-12-14 | 2012-12-19 | 6 | 11d | - | - |
|
Unscheduled
|
2012-12-01 | 2012-12-03 | 3 | 23d | - | - |
|
Scram
# 48477
|
2012-11-04 | 2012-11-08 | 5 | 3d | - | - |
|
Scram
# 48453
|
2012-10-30 | 2012-11-01 | 3 | 36d | - | - |
|
Scram
# 48323
|
2012-09-21 | 2012-09-24 | 4 | 64d | - | - |
|
Scram
# 48110
|
2012-07-18 | 2012-07-19 | 2 | 146d | - | - |
|
Unscheduled
|
2012-02-20 | 2012-02-23 | 4 | 278d | - | - |
|
Scram
# 46808
|
2011-05-03 | 2011-05-18 | 16 | 15d | - | - |
|
Scheduled
|
2011-03-21 | 2011-04-18 | 29 | 129d | 2011-03-19 | +2d |
|
Unscheduled
|
2010-11-11 | 2010-11-12 | 2 | 400d | - | - |
|
Unscheduled
|
2009-10-06 | 2009-10-07 | 2 | 181d | - | - |
|
Scheduled
|
2009-03-21 | 2009-04-08 | 19 | 146d | 2009-03-21 | 0d |
|
Unscheduled
|
2008-10-24 | 2008-10-26 | 3 | 522d | - | - |
|
Unscheduled
|
2007-05-18 | 2007-05-21 | 4 | 33d | - | - |
|
Scheduled
|
2007-03-17 | 2007-04-15 | 30 | 278d | 2007-03-16 | +1d |
|
Unscheduled
|
2006-06-12 | 2006-06-12 | 1 | 297d | - | - |
|
Unscheduled
|
2005-08-19 | 2005-08-19 | 1 | 114d | - | - |
|
Scheduled
|
2005-03-21 | 2005-04-27 | 38 | 12d | 2005-03-20 | +1d |
|
Unscheduled
|
2005-03-08 | 2005-03-09 | 2 | 187d | - | - |
|
Unscheduled
|
2004-08-31 | 2004-09-02 | 3 | 120d | - | - |
|
Unscheduled
|
2004-04-27 | 2004-05-03 | 7 | 98d | - | - |
|
Unscheduled
|
2004-01-11 | 2004-01-20 | 10 | 147d | - | - |
|
Unscheduled
|
2003-08-15 | 2003-08-17 | 3 | 104d | - | - |
|
Unscheduled
|
2003-05-01 | 2003-05-03 | 3 | 2d | - | - |
|
Unscheduled
|
2003-04-27 | 2003-04-29 | 3 | 4d | - | - |
|
Scheduled
|
2003-03-15 | 2003-04-23 | 40 | 25d | 2003-03-15 | 0d |
|
Unscheduled
|
2003-02-14 | 2003-02-18 | 5 | 52d | - | - |
|
Unscheduled
|
2002-12-06 | 2002-12-24 | 19 | 203d | - | - |
|
Unscheduled
|
2002-05-15 | 2002-05-17 | 3 | 261d | - | - |
|
Unscheduled
|
2001-08-23 | 2001-08-27 | 5 | 110d | - | - |
|
Scheduled
|
2001-03-18 | 2001-05-05 | 49 | 160d | 2001-03-18 | 0d |
|
Unscheduled
|
2000-09-25 | 2000-10-09 | 15 | 139d | - | - |
|
Unscheduled
|
2000-05-01 | 2000-05-09 | 9 | 62d | - | - |
|
Unscheduled
|
2000-02-26 | 2000-02-29 | 4 | 105d | - | - |
|
Unscheduled
|
1999-10-28 | 1999-11-13 | 17 | 11d | - | - |
|
Unscheduled
|
1999-10-09 | 1999-10-17 | 9 | 65d | - | - |
|
Unscheduled
|
1999-07-24 | 1999-08-05 | 13 | 39d | - | - |
|
Scheduled
SGR/Major
|
1999-04-12 | 1999-06-15 | 65 | - | 1999-04-12 | 0d |
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