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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.
44
Excellence
#59 of 94 ↑15
Mid Quartile
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Days of continuous operation since the last outage ended. Has forced outage(s) since last refueling.
--
Current Run
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Longest recorded period of continuous operation between outages (2024-10-13 to 2026-04-18).
552
Record Run
days
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (456 days for this 18-month cycle unit) with no trips to 0% power.
2
B2B Runs
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Lifetime capacity factor: average power level across all recorded days (100% = always at full power).
87.4%
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.
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
44/100
Mid Quartile · #59/94
5-year window
Saint Lucie 2 ranks #59 of 94 active US units on NukeWorker's Operational Excellence Score over the 5-year window. Strongest area: Startup Duration (78th percentile). Weakest: Forced Outage Days/yr (20th percentile).
Reliability
34
Capacity factor + Forced outages + B2B streaks
Efficiency
37
Fuel utilization + Refuel duration
Discipline
63
Startup duration + Scram count
Cohort Rankings
apples-to-apples comparison within each peer group
Reactor type:
#41 of 61
PWR
Containment:
#34 of 48
Dry Ambient (PWR)
Cycle length:
#34 of 54
18-month cycle
Fleet rank above (59 of 94) compares all active US units; cohort ranks compare only against units sharing this property.
Per-dimension breakdown (7 metrics)
Capacity Factor
30th
89.0% (higher better, Reliability)
Forced Outage Days/yr
20th
8.6d (lower better, Reliability)
B2B Avg Streak
51th
519d (higher better, Reliability)
Fuel Utilization
20th
96.0% (higher better, Efficiency)
Refuel Duration
53th
32d (lower better, Efficiency)
Startup Duration
78th
3.4d (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:
↑ +9.7 pts vs 2025
Compare Saint Lucie 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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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
|
2026-04-18 | In Outage | 26+ | 552d | 2026-04-04 | +14d |
|
Scheduled
|
2024-08-31 | 2024-10-13 | 44 | 69d | 2024-08-31 | 0d |
|
Scram
# 57177
|
2024-06-18 | 2024-06-23 | 6 | 12d | - | - |
|
Scram
# 57161
|
2024-06-05 | 2024-06-06 | 2 | 147d | - | - |
|
Unscheduled
|
2024-01-04 | 2024-01-10 | 7 | 16d | - | - |
|
Unscheduled
|
2023-12-10 | 2023-12-19 | 10 | 267d | - | - |
|
Scheduled
|
2023-02-18 | 2023-03-18 | 29 | 394d | 2023-02-18 | 0d |
|
Unscheduled
|
2022-01-07 | 2022-01-20 | 14 | 100d | - | - |
|
Scheduled
|
2021-08-28 | 2021-09-29 | 33 | 218d | 2021-08-28 | 0d |
|
Scram
# 55078
|
2021-01-21 | 2021-01-22 | 2 | 309d | - | - |
|
Scheduled
|
2020-02-17 | 2020-03-18 | 31 | 488d | 2020-02-17 | 0d |
|
Scram
# 53665
|
2018-10-13 | 2018-10-17 | 5 | 11d | - | - |
|
Scheduled
|
2018-08-27 | 2018-10-02 | 37 | 303d | 2018-08-27 | 0d |
|
Scram
# 53036
|
2017-10-26 | 2017-10-28 | 3 | 216d | - | - |
|
Scheduled
|
2017-02-20 | 2017-03-24 | 33 | 130d | 2017-02-20 | 0d |
|
Unscheduled
|
2016-10-07 | 2016-10-13 | 7 | 348d | - | - |
|
Scheduled
|
2015-09-08 | 2015-10-25 | 48 | 140d | 2015-09-06 | +2d |
|
Unscheduled
|
2015-04-12 | 2015-04-21 | 10 | 53d | - | - |
|
Unscheduled
|
2015-02-16 | 2015-02-18 | 3 | 90d | - | - |
|
Scram
# 50607
|
2014-11-13 | 2014-11-18 | 6 | 100d | - | - |
|
Unscheduled
|
2014-07-26 | 2014-08-05 | 11 | 95d | - | - |
|
Scheduled
|
2014-03-03 | 2014-04-22 | 51 | 107d | 2014-03-03 | 0d |
|
Scram
# 49536
|
2013-11-15 | 2013-11-16 | 2 | 166d | - | - |
|
Scram
# 49082
|
2013-06-01 | 2013-06-02 | 2 | 194d | - | - |
|
Scheduled
SGR/Major
|
2012-08-06 | 2012-11-19 | 106 | 86d | 2012-08-05 | +1d |
|
Scram
# 47915
|
2012-05-11 | 2012-05-12 | 2 | 340d | - | - |
|
Scram
# 46928
|
2011-06-06 | 2011-06-06 | 1 | 20d | - | - |
|
Unscheduled
|
2011-05-16 | 2011-05-17 | 2 | 12d | - | - |
|
Scheduled
SGR/Major
|
2011-01-03 | 2011-05-04 | 122 | 257d | 2011-01-05 | -2d |
|
Unscheduled
|
2010-04-16 | 2010-04-21 | 6 | 199d | - | - |
|
Unscheduled
|
2009-09-10 | 2009-09-29 | 20 | 45d | - | - |
|
Unscheduled
|
2009-07-13 | 2009-07-27 | 15 | 31d | - | - |
|
Scheduled
|
2009-04-27 | 2009-06-12 | 47 | 24d | 2009-04-27 | 0d |
|
Unscheduled
|
2009-04-02 | 2009-04-03 | 2 | 298d | - | - |
|
Unscheduled
|
2008-06-08 | 2008-06-08 | 1 | 2d | - | - |
|
Unscheduled
|
2008-06-05 | 2008-06-06 | 2 | 118d | - | - |
|
Unscheduled
|
2008-01-30 | 2008-02-08 | 10 | 26d | - | - |
|
Scheduled
SGR/Major
|
2007-10-01 | 2008-01-04 | 96 | 32d | 2007-10-01 | 0d |
|
Unscheduled
|
2007-08-19 | 2007-08-30 | 12 | 429d | - | - |
|
Unscheduled
|
2006-06-16 | 2006-06-16 | 1 | 5d | - | - |
|
Scheduled
|
2006-04-24 | 2006-06-11 | 49 | 91d | 2006-04-23 | +1d |
|
Unscheduled
|
2006-01-21 | 2006-01-23 | 3 | 86d | - | - |
|
Unscheduled
|
2005-10-24 | 2005-10-27 | 4 | 73d | - | - |
|
Unscheduled
|
2005-08-12 | 2005-08-12 | 1 | 179d | - | - |
|
Unscheduled
|
2005-01-06 | 2005-02-14 | 40 | 5d | - | - |
|
Unscheduled
|
2004-12-28 | 2005-01-01 | 5 | 2d | - | - |
|
Unscheduled
|
2004-12-26 | 2004-12-26 | 1 | 83d | - | - |
|
Unscheduled
|
2004-09-26 | 2004-10-04 | 9 | 9d | - | - |
|
Scheduled
|
2004-09-04 | 2004-09-17 | 14 | 251d | 2004-10-19 (Enhanced) | -45d (Enhanced) |
|
Unscheduled
|
2003-12-27 | 2003-12-28 | 2 | 4d | - | - |
|
Unscheduled
|
2003-12-21 | 2003-12-23 | 3 | 16d | - | - |
|
Unscheduled
|
2003-12-05 | 2003-12-05 | 1 | 172d | - | - |
|
Unscheduled
|
2003-06-11 | 2003-06-16 | 6 | 3d | - | - |
|
Unscheduled
|
2003-06-07 | 2003-06-08 | 2 | 2d | - | - |
|
Scheduled
|
2003-04-21 | 2003-06-05 | 46 | 17d | 2003-04-21 | 0d |
|
Unscheduled
|
2003-04-02 | 2003-04-04 | 3 | 460d | - | - |
|
Unscheduled
Startup Hold
|
2001-12-26 | 2001-12-28 | 3 | 6d | - | - |
|
Scheduled
|
2001-11-26 | 2001-12-20 | 25 | 254d | 2001-11-26 | 0d |
|
Unscheduled
|
2001-03-15 | 2001-03-17 | 3 | 302d | - | - |
|
Scheduled
|
2000-04-17 | 2000-05-17 | 31 | 312d | 2000-04-17 | 0d |
|
Unscheduled
|
1999-06-04 | 1999-06-10 | 7 | - | - | - |
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