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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.
47
Excellence
#53 of 94 ↑8
Mid Quartile
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Days of continuous operation since the last outage ended. Clean run (no forced outages since last refueling).
196
Current Run
days ✔
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Longest recorded period of continuous operation between outages (2022-10-04 to 2024-03-09).
522
Record Run
days
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (450 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).
88.5%
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.
2.7
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.
98.3%
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
47/100
Mid Quartile · #53/94
5-year window
Saint Lucie 1 ranks #53 of 94 active US units on NukeWorker's Operational Excellence Score over the 5-year window. Strongest area: Startup Duration (83th percentile). Weakest: B2B Avg Streak (15th percentile).
Reliability
41
Capacity factor + Forced outages + B2B streaks
Efficiency
51
Fuel utilization + Refuel duration
Discipline
50
Startup duration + Scram count
Cohort Rankings
apples-to-apples comparison within each peer group
Reactor type:
#37 of 61
PWR
Containment:
#33 of 48
Dry Ambient (PWR)
Cycle length:
#30 of 54
18-month cycle
Fleet rank above (53 of 94) compares all active US units; cohort ranks compare only against units sharing this property.
Per-dimension breakdown (7 metrics)
Capacity Factor
56th
92.2% (higher better, Reliability)
Forced Outage Days/yr
52th
3.4d (lower better, Reliability)
B2B Avg Streak
15th
498d (higher better, Reliability)
Fuel Utilization
60th
98.2% (higher better, Efficiency)
Refuel Duration
42th
34d (lower better, Efficiency)
Startup Duration
83th
3.3d (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:
↑ +3.8 pts vs 2025
Compare Saint Lucie 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 31, 2025
62.9% remaining
194 / 520 days
1.2 FPD margin
Avg refuel: 5.3%
Avg refuel (3yr): 1.7%
Deepest burn: 0.0% (1999-10 → 2001-04)
Most margin: 12.6% (2018-04 → 2019-09)
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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
|
2025-09-20 | 2025-10-30 | 41 | 307d | 2025-09-20 | 0d |
|
Scram
# 57425
|
2024-11-16 | 2024-11-17 | 2 | 105d | - | - |
|
Scram
# 57249
|
2024-07-29 | 2024-08-03 | 6 | 108d | - | - |
|
Scheduled
|
2024-03-09 | 2024-04-12 | 35 | 522d | 2024-03-08 | +1d |
|
Scheduled
|
2022-09-03 | 2022-10-04 | 32 | 266d | 2022-09-03 | 0d |
|
Scram
# 55641
|
2021-12-11 | 2021-12-11 | 1 | 208d | - | - |
|
Scheduled
|
2021-04-10 | 2021-05-17 | 38 | 509d | 2021-04-10 | 0d |
|
Unscheduled
|
2019-10-14 | 2019-11-18 | 36 | 23d | - | - |
|
Scheduled
|
2019-09-08 | 2019-09-21 | 14 | 81d | 2019-09-03 | +5d |
|
Scram
# 54027
|
2019-04-26 | 2019-06-19 | 55 | 178d | - | - |
|
Scram
# 53703
|
2018-10-30 | 2018-10-30 | 1 | 202d | - | - |
|
Scheduled
|
2018-03-12 | 2018-04-11 | 31 | 181d | 2018-03-12 | 0d |
|
Unscheduled
|
2017-09-12 | 2017-09-12 | 1 | 217d | - | - |
|
Unscheduled
|
2017-02-01 | 2017-02-07 | 7 | 86d | - | - |
|
Scheduled
|
2016-09-26 | 2016-11-07 | 43 | 32d | 2016-09-26 | 0d |
|
Scram
# 52191
|
2016-08-22 | 2016-08-25 | 4 | 2d | - | - |
|
Unscheduled
|
2016-08-02 | 2016-08-20 | 19 | 357d | - | - |
|
Scram
# 51302
|
2015-08-10 | 2015-08-11 | 2 | 110d | - | - |
|
Scheduled
|
2015-03-23 | 2015-04-22 | 31 | 460d | 2015-03-23 | 0d |
|
Unscheduled
|
2013-12-11 | 2013-12-18 | 8 | 29d | - | - |
|
Scram
# 49528
|
2013-11-12 | 2013-11-12 | 1 | 5d | - | - |
|
Scheduled
|
2013-09-30 | 2013-11-07 | 39 | 183d | 2013-09-29 | +1d |
|
Scram
# 48818
|
2013-03-13 | 2013-03-31 | 19 | 232d | - | - |
|
Unscheduled
|
2012-07-19 | 2012-07-24 | 6 | 44d | - | - |
|
Scram
# 47987
|
2012-06-03 | 2012-06-05 | 3 | 51d | - | - |
|
Unscheduled
|
2012-04-07 | 2012-04-13 | 7 | 2d | - | - |
|
Scram
# 47793
|
2012-03-31 | 2012-04-05 | 6 | 2d | - | - |
|
Scheduled
SGR/Major
|
2011-11-28 | 2012-03-29 | 123 | 32d | 2011-11-23 | +5d |
|
Unscheduled
|
2011-10-26 | 2011-10-27 | 2 | 6d | - | - |
|
Scram
# 47353
|
2011-10-20 | 2011-10-20 | 1 | 55d | - | - |
|
Scram
# 47178
|
2011-08-23 | 2011-08-26 | 4 | 423d | - | - |
|
Unscheduled
|
2010-06-17 | 2010-06-26 | 10 | 4d | - | - |
|
Scheduled
|
2010-04-05 | 2010-06-13 | 70 | 501d | 2010-04-05 | 0d |
|
Scheduled
|
2008-10-20 | 2008-11-20 | 32 | 57d | 2008-10-19 | +1d |
|
Unscheduled
|
2008-08-21 | 2008-08-24 | 4 | 453d | - | - |
|
Scheduled
|
2007-04-02 | 2007-05-26 | 55 | 470d | 2007-04-01 | +1d |
|
Scheduled
|
2005-10-17 | 2005-12-18 | 63 | 380d | 2005-10-16 | +1d |
|
Unscheduled
|
2004-09-26 | 2004-10-02 | 7 | 13d | - | - |
|
Unscheduled
|
2004-09-05 | 2004-09-13 | 9 | 134d | - | - |
|
Scheduled
|
2004-03-22 | 2004-04-24 | 34 | 515d | 2004-03-21 | +1d |
|
Scheduled
|
2002-09-30 | 2002-10-24 | 25 | 323d | 2002-09-30 | 0d |
|
Unscheduled
|
2001-11-09 | 2001-11-11 | 3 | 156d | - | - |
|
Unscheduled
|
2001-06-06 | 2001-06-06 | 1 | 38d | - | - |
|
Scheduled
|
2001-04-02 | 2001-04-29 | 28 | 520d | 2001-04-02 | 0d |
|
Unscheduled
|
1999-10-29 | 1999-10-30 | 2 | 12d | - | - |
|
Scheduled
|
1999-09-13 | 1999-10-17 | 35 | 18d | 1999-09-13 | 0d |
|
Unscheduled
|
1999-08-24 | 1999-08-26 | 3 | - | - | - |
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