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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.
12
Excellence
#93 of 94 →
Bottom Quartile
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Days of continuous operation since the last outage ended. Clean run (no forced outages since last refueling).
342
Current Run
days ✔
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Longest recorded period of continuous operation between outages (2017-07-29 to 2019-01-05).
525
Record Run
days
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (446 days for this 18-month cycle unit) with no trips to 0% power.
3
B2B Runs
75% toward B2B (334/446d)
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Lifetime capacity factor: average power level across all recorded days (100% = always at full power).
87%
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.
8
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.
69.5%
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
12/100
Bottom Quartile · #93/94
5-year window
Waterford 3 ranks #93 of 94 active US units on NukeWorker's Operational Excellence Score over the 5-year window. Strongest area: B2B Avg Streak (40th percentile). Weakest: Refuel Duration (1th percentile).
Reliability
20
Capacity factor + Forced outages + B2B streaks
Efficiency
1
Fuel utilization + Refuel duration
Discipline
14
Startup duration + Scram count
Cohort Rankings
apples-to-apples comparison within each peer group
Reactor type:
#61 of 61
PWR
Containment:
#48 of 48
Dry Ambient (PWR)
Cycle length:
#54 of 54
18-month cycle
Fleet rank above (93 of 94) compares all active US units; cohort ranks compare only against units sharing this property.
Per-dimension breakdown (7 metrics)
Capacity Factor
10th
81.0% (higher better, Reliability)
Forced Outage Days/yr
10th
16.8d (lower better, Reliability)
B2B Avg Streak
40th
509d (higher better, Reliability)
Fuel Utilization
2th
86.3% (higher better, Efficiency)
Refuel Duration
1th
77d (lower better, Efficiency)
Startup Duration
12th
7.9d (lower better, Discipline)
Scrams (5-year)
16th
0.8/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:
Stable vs 2025
Compare Waterford 3 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 Jun 8, 2025
34.4% remaining
339 / 480 days
24.2 FPD margin
Avg refuel: 2.7%
Avg refuel (3yr): 30.5%
Deepest burn: 0.0% (1999-04 → 2000-10)
Most margin: 30.5% (2024-02 → 2025-04)
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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 |
|---|---|---|---|---|---|---|
|
Scheduled
|
2025-04-26 | 2025-06-06 | 42 | 138d | 2025-04-01 | +25d |
|
Unscheduled
|
2024-12-03 | 2024-12-09 | 7 | 168d | - | - |
|
Scram
# 57175
|
2024-06-17 | 2024-06-18 | 2 | 34d | - | - |
|
Scram
# 57042
|
2024-03-22 | 2024-05-14 | 54 | 4d | - | - |
|
Scram
# 57032
|
2024-03-17 | 2024-03-18 | 2 | 45d | - | - |
|
Scheduled
SGR/Major
|
2023-10-14 | 2024-02-01 | 111 | 214d | 2023-10-14 | 0d |
|
Unscheduled
|
2023-03-11 | 2023-03-14 | 4 | 257d | - | - |
|
Scram
# 55963
|
2022-06-25 | 2022-06-27 | 3 | 7d | - | - |
|
Scheduled
|
2022-04-02 | 2022-06-18 | 78 | 207d | 2022-04-02 | 0d |
|
Unscheduled
|
2021-08-30 | 2021-09-07 | 9 | 149d | - | - |
|
Unscheduled
|
2021-04-01 | 2021-04-03 | 3 | 108d | - | - |
|
Unscheduled
|
2020-12-12 | 2020-12-14 | 3 | 38d | - | - |
|
Unscheduled
|
2020-11-03 | 2020-11-04 | 2 | 3d | - | - |
|
Scheduled
|
2020-09-26 | 2020-10-31 | 36 | 416d | 2020-09-26 | 0d |
|
Unscheduled
|
2019-08-01 | 2019-08-07 | 7 | 65d | - | - |
|
Scram
# 54068
|
2019-05-17 | 2019-05-28 | 12 | 62d | - | - |
|
Scheduled
|
2019-01-05 | 2019-03-16 | 71 | 525d | 2019-01-05 | 0d |
|
Scram
# 52863
|
2017-07-18 | 2017-07-29 | 12 | 47d | - | - |
|
Scheduled
|
2017-04-15 | 2017-06-01 | 48 | 167d | 2017-04-15 | 0d |
|
Unscheduled
|
2016-10-25 | 2016-10-30 | 6 | 315d | - | - |
|
Scheduled
|
2015-10-25 | 2015-12-15 | 52 | 20d | 2015-10-18 | +7d |
|
Scram
# 51447
|
2015-10-04 | 2015-10-05 | 2 | 102d | - | - |
|
Unscheduled
|
2015-06-23 | 2015-06-24 | 2 | 17d | - | - |
|
Scram
# 51116
|
2015-06-04 | 2015-06-06 | 3 | 386d | - | - |
|
Scheduled
|
2014-04-13 | 2014-05-14 | 32 | 347d | 2014-04-13 | 0d |
|
Unscheduled
|
2013-04-27 | 2013-05-01 | 5 | 94d | - | - |
|
Scram
# 48687
|
2013-01-22 | 2013-01-23 | 2 | 5d | - | - |
|
Scheduled
SGR/Major
|
2012-10-17 | 2013-01-17 | 93 | 45d | 2012-10-17 | 0d |
|
Unscheduled
|
2012-08-29 | 2012-09-02 | 5 | 476d | - | - |
|
Scheduled
|
2011-04-06 | 2011-05-11 | 36 | 490d | 2011-03-30 | +7d |
|
Scheduled
|
2009-10-20 | 2009-12-02 | 44 | 406d | 2009-10-25 | -5d |
|
Unscheduled
|
2008-09-01 | 2008-09-09 | 9 | 93d | - | - |
|
Scheduled
|
2008-04-27 | 2008-05-31 | 35 | 188d | 2008-04-27 | 0d |
|
Unscheduled
|
2007-10-09 | 2007-10-22 | 14 | 286d | - | - |
|
Scheduled
|
2006-11-26 | 2006-12-27 | 32 | 377d | 2006-11-25 | +1d |
|
Unscheduled
|
2005-11-12 | 2005-11-14 | 3 | 60d | - | - |
|
Unscheduled
|
2005-08-29 | 2005-09-13 | 16 | 80d | - | - |
|
Scheduled
|
2005-04-17 | 2005-06-10 | 55 | 514d | 2005-04-16 | +1d |
|
Scheduled
|
2003-10-20 | 2003-11-20 | 32 | 245d | 2003-10-20 | 0d |
|
Unscheduled
|
2003-02-16 | 2003-02-17 | 2 | 305d | - | - |
|
Scheduled
|
2002-03-23 | 2002-04-17 | 26 | 402d | 2002-03-23 | 0d |
|
Unscheduled
|
2001-02-14 | 2001-02-14 | 1 | 89d | - | - |
|
Scheduled
|
2000-10-14 | 2000-11-17 | 35 | 122d | 2000-10-14 | 0d |
|
Unscheduled
|
2000-06-09 | 2000-06-14 | 6 | 94d | - | - |
|
Unscheduled
|
2000-03-07 | 2000-03-07 | 1 | 97d | - | - |
|
Unscheduled
|
1999-11-27 | 1999-12-01 | 5 | 59d | - | - |
|
Unscheduled
|
1999-09-11 | 1999-09-29 | 19 | 32d | - | - |
|
Unscheduled
|
1999-08-02 | 1999-08-10 | 9 | 47d | - | - |
|
Unscheduled
|
1999-06-15 | 1999-06-16 | 2 | 75d | - | - |
|
Scheduled
|
1999-02-20 | 1999-04-01 | 41 | - | 1999-02-20 | 0d |
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