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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.
22
Excellence
#88 of 94 ↓9
Bottom Quartile
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Days of continuous operation since the last outage ended. Clean run (no forced outages since last refueling).
388
Current Run
days ✔
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Longest recorded period of continuous operation between outages (2017-04-02 to 2019-02-25).
694
Record Run
days
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (614 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).
87.2%
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.
94.3%
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
22/100
Bottom Quartile · #88/94
5-year window
Perry 1 ranks #88 of 94 active US units on NukeWorker's Operational Excellence Score over the 5-year window. Strongest area: Scrams (5-year) (48th percentile). Weakest: Fuel Utilization (7th percentile).
Reliability
31
Capacity factor + Forced outages + B2B streaks
Efficiency
7
Fuel utilization + Refuel duration
Discipline
28
Startup duration + Scram count
Cohort Rankings
apples-to-apples comparison within each peer group
Reactor type:
#28 of 31
BWR
Containment:
#2 of 4
Mark III (BWR)
Cycle length:
#37 of 40
24-month cycle
Fleet rank above (88 of 94) compares all active US units; cohort ranks compare only against units sharing this property.
Per-dimension breakdown (7 metrics)
Capacity Factor
39th
89.9% (higher better, Reliability)
Forced Outage Days/yr
23th
7.2d (lower better, Reliability)
Fuel Utilization
7th
93.8% (higher better, Efficiency)
Refuel Duration
7th
49d (lower better, Efficiency)
Startup Duration
8th
8.3d (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:
↓ -7.0 pts vs 2025
Compare Perry 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 22, 2025
45.1% remaining
386 / 697 days
3.2 FPD margin
Avg refuel: 9.1%
Avg refuel (3yr): 5.7%
Deepest burn: 2.3% (2017-04 → 2019-03)
Most margin: 19.6% (2003-05 → 2005-02)
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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 | 2025-04-21 | 36 | 8d | 2025-03-07 | +10d |
|
Unscheduled
|
2025-02-27 | 2025-03-09 | 11 | 278d | - | - |
|
Unscheduled
|
2024-05-24 | 2024-05-25 | 2 | 8d | - | - |
|
Unscheduled
|
2024-05-11 | 2024-05-16 | 6 | 270d | - | - |
|
Scram
# 56673
|
2023-08-10 | 2023-08-15 | 6 | 116d | - | - |
|
Scheduled
|
2023-02-26 | 2023-04-16 | 50 | 49d | 2023-03-05 | -7d |
|
Scram
# 56298
|
2023-01-06 | 2023-01-08 | 3 | 61d | - | - |
|
Unscheduled
|
2022-11-01 | 2022-11-06 | 6 | 572d | - | - |
|
Scheduled
|
2021-03-07 | 2021-04-08 | 33 | 586d | 2021-03-08 | -1d |
|
Scram
# 54185
|
2019-07-28 | 2019-07-30 | 3 | 114d | - | - |
|
Scheduled
|
2019-03-10 | 2019-04-05 | 27 | 10d | 2019-03-09 | +1d |
|
Scram
# 53896
|
2019-02-25 | 2019-02-28 | 4 | 694d | - | - |
|
Scheduled
|
2017-03-05 | 2017-04-02 | 29 | 387d | 2017-03-07 | -2d |
|
Scram
# 51716
|
2016-02-09 | 2016-02-12 | 4 | 9d | - | - |
|
Scram
# 51679
|
2016-01-25 | 2016-01-31 | 7 | 276d | - | - |
|
Scheduled
|
2015-03-09 | 2015-04-24 | 47 | 118d | 2015-02-23 | +14d |
|
Scram
# 50601
|
2014-11-08 | 2014-11-11 | 4 | 14d | - | - |
|
Scram
# 50551
|
2014-10-20 | 2014-10-25 | 6 | 407d | - | - |
|
Unscheduled
|
2013-09-07 | 2013-09-08 | 2 | 79d | - | - |
|
Unscheduled
|
2013-06-16 | 2013-06-20 | 5 | 36d | - | - |
|
Scheduled
|
2013-03-18 | 2013-05-11 | 55 | 51d | 2013-03-18 | 0d |
|
Scram
# 48688
|
2013-01-22 | 2013-01-26 | 5 | 219d | - | - |
|
Unscheduled
|
2012-06-15 | 2012-06-17 | 3 | 105d | - | - |
|
Scram
# 47710
|
2012-03-01 | 2012-03-02 | 2 | 135d | - | - |
|
Unscheduled
|
2011-10-03 | 2011-10-18 | 16 | 120d | - | - |
|
Scheduled
|
2011-04-18 | 2011-06-05 | 49 | 336d | 2011-04-18 | 0d |
|
Unscheduled
|
2010-05-12 | 2010-05-17 | 6 | 192d | - | - |
|
Unscheduled
|
2009-10-16 | 2009-11-01 | 17 | 114d | - | - |
|
Unscheduled
|
2009-06-22 | 2009-06-24 | 3 | 42d | - | - |
|
Scheduled
|
2009-02-23 | 2009-05-11 | 78 | 318d | 2009-02-23 | 0d |
|
Unscheduled
|
2008-04-04 | 2008-04-11 | 8 | 120d | - | - |
|
Unscheduled
|
2007-11-29 | 2007-12-06 | 8 | 129d | - | - |
|
Unscheduled
|
2007-06-30 | 2007-07-23 | 24 | 7d | - | - |
|
Unscheduled
|
2007-06-22 | 2007-06-23 | 2 | 36d | - | - |
|
Unscheduled
|
2007-05-15 | 2007-05-17 | 3 | 4d | - | - |
|
Scheduled
|
2007-04-02 | 2007-05-11 | 40 | 105d | 2007-04-01 | +1d |
|
Unscheduled
|
2006-12-14 | 2006-12-18 | 5 | 590d | - | - |
|
Scheduled
|
2005-02-22 | 2005-05-03 | 71 | 23d | 2005-02-21 | +1d |
|
Unscheduled
|
2005-01-06 | 2005-01-30 | 25 | 11d | - | - |
|
Unscheduled
|
2004-12-24 | 2004-12-26 | 3 | 203d | - | - |
|
Unscheduled
|
2004-05-23 | 2004-06-04 | 13 | 277d | - | - |
|
Unscheduled
|
2003-08-15 | 2003-08-20 | 6 | 78d | - | - |
|
Scheduled
|
2003-04-05 | 2003-05-29 | 55 | 184d | 2003-04-05 | 0d |
|
Unscheduled
|
2002-09-22 | 2002-10-03 | 12 | 104d | - | - |
|
Unscheduled
|
2002-06-05 | 2002-06-10 | 6 | 169d | - | - |
|
Unscheduled
|
2001-12-16 | 2001-12-18 | 3 | 139d | - | - |
|
Unscheduled
|
2001-07-18 | 2001-07-30 | 13 | 2d | - | - |
|
Unscheduled
|
2001-07-12 | 2001-07-16 | 5 | 40d | - | - |
|
Unscheduled
|
2001-05-22 | 2001-06-02 | 12 | 8d | - | - |
|
Unscheduled
|
2001-05-08 | 2001-05-14 | 7 | 4d | - | - |
|
Unscheduled
|
2001-04-29 | 2001-05-04 | 6 | 39d | - | - |
|
Scheduled
|
2001-02-17 | 2001-03-21 | 33 | 247d | 2001-02-17 | 0d |
|
Unscheduled
|
2000-06-05 | 2000-06-15 | 11 | 400d | - | - |
|
Scheduled
|
1999-03-27 | 1999-05-02 | 37 | - | 1999-03-27 | 0d |
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