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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.
18
Excellence
#91 of 94 ↓8
Bottom Quartile
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Days of continuous operation since the last outage ended. Clean run (no forced outages since last refueling).
17
Current Run
days ✔
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Longest recorded period of continuous operation between outages (2018-02-28 to 2019-05-01).
427
Record Run
days
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (617 days for this 24-month cycle unit) with no trips to 0% power.
0
B2B Runs
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Lifetime capacity factor: average power level across all recorded days (100% = always at full power).
90.1%
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.
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.
90.5%
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 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
18/100
Bottom Quartile · #91/94
5-year window
Hatch 1 ranks #91 of 94 active US units on NukeWorker's Operational Excellence Score over the 5-year window. Strongest area: Refuel Duration (35th percentile). Weakest: Scrams (5-year) (3th percentile).
Reliability
14
Capacity factor + Forced outages + B2B streaks
Efficiency
30
Fuel utilization + Refuel duration
Discipline
9
Startup duration + Scram count
Cohort Rankings
apples-to-apples comparison within each peer group
Reactor type:
#30 of 31
BWR
Containment:
#19 of 19
Mark I (BWR)
Cycle length:
#39 of 40
24-month cycle
Fleet rank above (91 of 94) compares all active US units; cohort ranks compare only against units sharing this property.
Per-dimension breakdown (7 metrics)
Capacity Factor
20th
86.8% (higher better, Reliability)
Forced Outage Days/yr
8th
17.6d (lower better, Reliability)
Fuel Utilization
26th
96.9% (higher better, Efficiency)
Refuel Duration
35th
35d (lower better, Efficiency)
Startup Duration
16th
7.2d (lower better, Discipline)
Scrams (5-year)
3th
1.2/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:
↓ -9.0 pts vs 2025
Compare Hatch 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 Mar 18, 2024
0.0% remaining
786 / 699 days
77.7 FPD margin
Avg refuel: 9.5%
Deepest burn: 2.2% (2018-03 → 2020-02)
Most margin: 30.7% (2000-11 → 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
| Type ⇅ | Actual Start ⇅ | Actual End ⇅ | Duration ⇅ | Days Online ⇅ | Scheduled | Delta |
|---|---|---|---|---|---|---|
|
Scram
# 58257
|
2026-04-24 | 2026-04-27 | 4 | 55d | - | - |
| 2026-01-17 | 2026-02-28 | 43 | 187d | - | - | |
|
Unscheduled
|
2025-07-12 | 2025-07-14 | 3 | 283d | - | - |
|
Scram
# 57343
|
2024-09-27 | 2024-10-02 | 6 | 194d | - | - |
|
Scram
# 57021
|
2024-03-12 | 2024-03-17 | 6 | 2d | - | - |
|
Scheduled
|
2024-02-04 | 2024-03-10 | 36 | 258d | 2024-02-05 | -1d |
|
Unscheduled
|
2023-05-20 | 2023-05-22 | 3 | 360d | - | - |
|
Unscheduled
|
2022-05-23 | 2022-05-25 | 3 | 83d | - | - |
|
Scheduled
|
2022-02-06 | 2022-03-01 | 24 | 35d | 2022-02-05 | +1d |
|
Scram
# 55679
|
2021-12-30 | 2022-01-02 | 4 | 146d | - | - |
|
Scram
# 55394
|
2021-08-04 | 2021-08-06 | 3 | 30d | - | - |
|
Unscheduled
|
2021-07-01 | 2021-07-05 | 5 | 14d | - | - |
|
Unscheduled
|
2021-06-12 | 2021-06-17 | 6 | 351d | - | - |
|
Unscheduled
|
2020-06-20 | 2020-06-26 | 7 | 97d | - | - |
|
Scheduled
|
2020-02-01 | 2020-03-15 | 44 | 271d | 2020-02-01 | 0d |
|
Unscheduled
|
2019-05-01 | 2019-05-06 | 6 | 427d | - | - |
|
Unscheduled
Startup Hold
|
2018-02-28 | 2018-02-28 | 1 | 3d | - | - |
|
Scheduled
|
2018-02-05 | 2018-02-25 | 21 | 289d | 2018-02-04 | +1d |
|
Unscheduled
|
2017-04-15 | 2017-04-22 | 8 | 6d | - | - |
|
Unscheduled
|
2017-04-08 | 2017-04-09 | 2 | 72d | - | - |
|
Unscheduled
|
2017-01-25 | 2017-01-26 | 2 | 279d | - | - |
|
Unscheduled
|
2016-04-20 | 2016-04-21 | 2 | 47d | - | - |
|
Scheduled
|
2016-02-08 | 2016-03-04 | 26 | 384d | 2016-02-07 | +1d |
|
Unscheduled
|
2015-01-19 | 2015-01-20 | 2 | 34d | - | - |
|
Unscheduled
|
2014-12-13 | 2014-12-16 | 4 | 284d | - | - |
|
Scheduled
|
2014-02-03 | 2014-03-04 | 30 | 102d | 2014-02-03 | 0d |
|
Unscheduled
|
2013-10-22 | 2013-10-24 | 3 | 239d | - | - |
|
Scram
# 48738
|
2013-02-11 | 2013-02-25 | 15 | 328d | - | - |
|
Scheduled
|
2012-02-13 | 2012-03-20 | 37 | 422d | 2012-02-13 | 0d |
|
Unscheduled
|
2010-12-17 | 2010-12-18 | 2 | 274d | - | - |
|
Scheduled
|
2010-02-08 | 2010-03-18 | 39 | 263d | 2010-02-06 | +2d |
|
Unscheduled
|
2009-05-11 | 2009-05-21 | 11 | 2d | - | - |
|
Unscheduled
|
2009-05-09 | 2009-05-09 | 1 | 2d | - | - |
|
Unscheduled
|
2009-05-04 | 2009-05-07 | 4 | 161d | - | - |
|
Unscheduled
|
2008-11-23 | 2008-11-24 | 2 | 140d | - | - |
|
Unscheduled
|
2008-07-05 | 2008-07-06 | 2 | 109d | - | - |
|
Unscheduled
|
2008-03-15 | 2008-03-18 | 4 | 4d | - | - |
|
Scheduled
|
2008-02-04 | 2008-03-11 | 37 | 366d | 2008-02-04 | 0d |
|
Unscheduled
|
2007-01-31 | 2007-02-03 | 4 | 309d | - | - |
|
Scheduled
|
2006-02-13 | 2006-03-28 | 44 | 91d | 2006-02-12 | +1d |
|
Unscheduled
|
2005-10-30 | 2005-11-14 | 16 | 292d | - | - |
|
Unscheduled
|
2005-01-03 | 2005-01-11 | 9 | 297d | - | - |
|
Scheduled
|
2004-02-14 | 2004-03-12 | 28 | 289d | 2004-02-13 | +1d |
|
Unscheduled
|
2003-04-19 | 2003-05-01 | 13 | 187d | - | - |
|
Unscheduled
|
2002-10-11 | 2002-10-14 | 4 | 172d | - | - |
|
Unscheduled
Startup Hold
|
2002-04-20 | 2002-04-22 | 3 | 2d | - | - |
|
Scheduled
|
2002-03-23 | 2002-04-18 | 27 | 39d | 2002-03-23 | 0d |
|
Unscheduled
|
2002-02-09 | 2002-02-12 | 4 | 316d | - | - |
|
Unscheduled
|
2001-03-29 | 2001-03-30 | 2 | 141d | - | - |
|
Unscheduled
|
2000-11-07 | 2000-11-08 | 2 | 6d | - | - |
|
Scheduled
|
2000-09-30 | 2000-11-01 | 33 | 79d | 2000-09-30 | 0d |
|
Unscheduled
|
2000-07-11 | 2000-07-13 | 3 | 158d | - | - |
|
Unscheduled
|
2000-01-27 | 2000-02-04 | 9 | 278d | - | - |
|
Scheduled
|
1999-03-01 | 1999-04-24 | 55 | - | 1999-03-01 | 0d |
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