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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.
52
Excellence
#40 of 94 →
Mid Quartile
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Days of continuous operation since the last outage ended. Clean run (no forced outages since last refueling).
163
Current Run
days ✔
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Longest recorded period of continuous operation between outages (2022-11-09 to 2024-04-06).
514
Record Run
days
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (433 days for this 18-month cycle unit) with no trips to 0% power.
6
B2B Runs
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Lifetime capacity factor: average power level across all recorded days (100% = always at full power).
89%
Capacity Factor
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Total number of scheduled refueling outages detected in the historical data.
18
Outages
since 2000
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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.
5.3
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.
99.6%
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
52/100
Mid Quartile · #40/94
5-year window
Palo Verde 3 ranks #40 of 94 active US units on NukeWorker's Operational Excellence Score over the 5-year window. Strongest area: Fuel Utilization (80th percentile). Weakest: B2B Avg Streak (8th percentile).
Reliability
42
Capacity factor + Forced outages + B2B streaks
Efficiency
54
Fuel utilization + Refuel duration
Discipline
58
Startup duration + Scram count
Cohort Rankings
apples-to-apples comparison within each peer group
Reactor type:
#28 of 61
PWR
Containment:
#23 of 48
Dry Ambient (PWR)
Cycle length:
#22 of 54
18-month cycle
Fleet rank above (40 of 94) compares all active US units; cohort ranks compare only against units sharing this property.
Per-dimension breakdown (7 metrics)
Capacity Factor
51th
91.1% (higher better, Reliability)
Forced Outage Days/yr
68th
2.2d (lower better, Reliability)
B2B Avg Streak
8th
490d (higher better, Reliability)
Fuel Utilization
80th
98.7% (higher better, Efficiency)
Refuel Duration
29th
36d (lower better, Efficiency)
Startup Duration
46th
4.7d (lower better, Discipline)
Scrams (5-year)
70th
0.2/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:
Stable vs 2025
Compare Palo Verde 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 Dec 4, 2025
68.8% remaining
160 / 508 days
1.3 FPD margin
Avg refuel: 4.5%
Avg refuel (3yr): 0.4%
Deepest burn: 0.0% (2012-04 → 2013-10)
Most margin: 18.2% (2004-12 → 2006-04)
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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
|
2025-10-04 | 2025-12-02 | 60 | 510d | 2025-09-25 | +9d |
|
Scheduled
|
2024-04-06 | 2024-05-12 | 37 | 514d | 2024-04-05 | +1d |
|
Scheduled
|
2022-10-08 | 2022-11-09 | 33 | 303d | 2022-10-08 | 0d |
|
Scram
# 55626
|
2021-12-07 | 2021-12-09 | 3 | 204d | - | - |
|
Scheduled
|
2021-04-10 | 2021-05-17 | 38 | 419d | 2021-04-10 | 0d |
|
Unscheduled
|
2020-02-09 | 2020-02-16 | 8 | 81d | - | - |
|
Scheduled
|
2019-10-05 | 2019-11-20 | 47 | 462d | 2019-09-29 | +6d |
|
Scram
# 53477
|
2018-06-28 | 2018-06-30 | 3 | 55d | - | - |
|
Scheduled
|
2018-04-07 | 2018-05-04 | 28 | 328d | 2018-04-07 | 0d |
|
Unscheduled
|
2017-05-10 | 2017-05-14 | 5 | 187d | - | - |
|
Scheduled
|
2016-10-08 | 2016-11-04 | 28 | 16d | 2016-10-07 | +1d |
|
Unscheduled
|
2016-09-20 | 2016-09-22 | 3 | 506d | - | - |
|
Scheduled
|
2015-04-04 | 2015-05-03 | 30 | 495d | 2015-04-04 | 0d |
|
Scheduled
|
2013-10-05 | 2013-11-25 | 52 | 339d | 2013-10-05 | 0d |
|
Unscheduled
|
2012-10-25 | 2012-10-31 | 7 | 191d | - | - |
|
Scheduled
|
2012-03-17 | 2012-04-17 | 32 | 421d | 2012-03-17 | 0d |
|
Scram
# 46556
|
2011-01-20 | 2011-01-21 | 2 | 72d | - | - |
|
Scheduled
|
2010-10-02 | 2010-11-09 | 39 | 301d | 2010-10-02 | 0d |
|
Unscheduled
|
2009-12-04 | 2009-12-05 | 2 | 191d | - | - |
|
Scheduled
|
2009-04-04 | 2009-05-27 | 54 | 187d | 2009-04-04 | 0d |
|
Unscheduled
|
2008-09-28 | 2008-09-29 | 2 | 9d | - | - |
|
Unscheduled
|
2008-09-17 | 2008-09-19 | 3 | 246d | - | - |
|
Scheduled
SGR/Major
|
2007-09-29 | 2008-01-15 | 109 | 151d | 2007-09-29 | 0d |
|
Unscheduled
|
2007-04-13 | 2007-05-01 | 19 | 72d | - | - |
|
Unscheduled
|
2007-01-27 | 2007-01-31 | 5 | 99d | - | - |
|
Unscheduled
|
2006-10-19 | 2006-10-20 | 2 | 108d | - | - |
|
Unscheduled
|
2006-07-02 | 2006-07-03 | 2 | 51d | - | - |
|
Scheduled
|
2006-04-01 | 2006-05-12 | 42 | 26d | 2006-03-31 | +1d |
|
Unscheduled
|
2006-03-06 | 2006-03-06 | 1 | 137d | - | - |
|
Unscheduled
|
2005-10-12 | 2005-10-20 | 9 | 6d | - | - |
|
Unscheduled
|
2005-10-02 | 2005-10-06 | 5 | 82d | - | - |
|
Unscheduled
|
2005-07-06 | 2005-07-12 | 7 | 13d | - | - |
|
Unscheduled
|
2005-05-23 | 2005-06-23 | 32 | 168d | - | - |
|
Scheduled
|
2004-10-02 | 2004-12-06 | 66 | 105d | 2004-10-02 | 0d |
|
Unscheduled
|
2004-06-15 | 2004-06-19 | 5 | 6d | - | - |
|
Unscheduled
|
2004-06-08 | 2004-06-09 | 2 | 93d | - | - |
|
Unscheduled
|
2004-02-29 | 2004-03-07 | 8 | 209d | - | - |
|
Unscheduled
|
2003-07-29 | 2003-08-04 | 7 | 39d | - | - |
|
Unscheduled
|
2003-06-19 | 2003-06-20 | 2 | 50d | - | - |
|
Scheduled
|
2003-03-29 | 2003-04-30 | 33 | 510d | 2003-03-29 | 0d |
|
Scheduled
|
2001-09-29 | 2001-11-04 | 37 | 41d | 2001-09-29 | 0d |
|
Unscheduled
|
2001-08-18 | 2001-08-19 | 2 | 89d | - | - |
|
Unscheduled
|
2001-05-20 | 2001-05-21 | 2 | 81d | - | - |
|
Unscheduled
|
2001-02-17 | 2001-02-28 | 12 | 138d | - | - |
|
Unscheduled
|
2000-09-28 | 2000-10-02 | 5 | 150d | - | - |
|
Scheduled
|
2000-04-01 | 2000-05-01 | 31 | - | 2000-04-01 | 0d |
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