Comanche Peak 1 - Status & History

Comprehensive reactor performance metrics, cycle analysis, and historical outage data.

Plant Info Outage History Daily Power Log
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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.
55
Excellence
#34 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).
230
Current Run
days ✔
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Longest recorded period of continuous operation between outages (2017-11-06 to 2019-04-22).
532
Record Run
days
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (462 days for this 18-month cycle unit) with no trips to 0% power.
8
B2B Runs
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Lifetime capacity factor: average power level across all recorded days (100% = always at full power).
92.6%
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.
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.
99.5%
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.
Time window — change how far back we look
NukeWorker's
Operational
Excellence Score
55/100
Mid Quartile · #34/94
5-year window

Comanche Peak 1 ranks #34 of 94 active US units on NukeWorker's Operational Excellence Score over the 5-year window. Strongest area: Capacity Factor (83th percentile). Weakest: Scrams (5-year) (30th percentile).

Reliability
58
Capacity factor + Forced outages + B2B streaks
Efficiency
54
Fuel utilization + Refuel duration
Discipline
52
Startup duration + Scram count
Cohort Rankings apples-to-apples comparison within each peer group
Reactor type: #22 of 61 PWR
Containment: #19 of 48 Dry Ambient (PWR)
Cycle length: #17 of 54 18-month cycle
Fleet rank above (34 of 94) compares all active US units; cohort ranks compare only against units sharing this property.
Per-dimension breakdown (7 metrics)
Capacity Factor 83th
94.7% (higher better, Reliability)
Forced Outage Days/yr 49th
3.8d (lower better, Reliability)
B2B Avg Streak 41th
510d (higher better, Reliability)
Fuel Utilization 42th
97.7% (higher better, Efficiency)
Refuel Duration 67th
28d (lower better, Efficiency)
Startup Duration 74th
3.5d (lower better, Discipline)
Scrams (5-year) 30th
0.6/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: 2021: 72/100 (#20/93)2022: 55/100 (#39/92)2023: 47/100 (#50/92)2024: 54/100 (#37/93)2025: 50/100 (#45/94)2026: 52/100 (#41/94) Stable vs 2025
Compare Comanche Peak 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 May 15, 2025

30.5% remaining 363 / 518 days 3.1 FPD margin
Avg refuel: 2.4% Avg refuel (3yr): 0.5% Deepest burn: 0.0% (2007-04 → 2008-09) Most margin: 10.7% (2002-11 → 2004-03)
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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
Scram # 57950
2025-09-25 2025-09-26 2 134d - -
Scheduled
2025-04-21 2025-05-14 24 340d 2025-04-17 +4d
Unscheduled
2024-05-11 2024-05-16 6 180d - -
Scheduled
2023-10-16 2023-11-13 29 121d 2023-10-15 +1d
Scram # 56580
2023-06-17 2023-06-17 1 278d - -
Scram # 56091
2022-09-06 2022-09-12 7 115d - -
Scheduled
2022-04-11 2022-05-14 34 519d 2022-04-20 -9d
Unscheduled Startup Hold
2020-11-07 2020-11-08 2 2d - -
Scheduled
2020-10-11 2020-11-05 26 504d 2020-10-20 -9d
Scheduled
2019-04-22 2019-05-26 35 532d 2019-04-21 +1d
Scheduled
2017-10-09 2017-11-06 29 496d 2017-10-31 -22d
Scheduled
2016-05-02 2016-05-31 30 523d 2016-05-02 0d
Scheduled
2014-10-05 2014-11-26 53 258d 2014-10-04 +1d
Scram # 49743
2014-01-19 2014-01-20 2 176d - -
Unscheduled
2013-07-27 2013-07-27 1 97d - -
Scheduled
2013-03-31 2013-04-21 22 140d 2013-03-30 +1d
Scram # 48475
2012-11-02 2012-11-11 10 378d - -
Scheduled
2011-10-02 2011-10-21 20 76d 2011-10-01 +1d
Unscheduled
2011-07-12 2011-07-18 7 179d - -
Unscheduled
2011-01-14 2011-01-14 1 263d - -
Scheduled
2010-04-04 2010-04-26 23 73d 2010-04-03 +1d
Unscheduled
2010-01-19 2010-01-21 3 9d - -
Unscheduled
2010-01-10 2010-01-10 1 451d - -
Scheduled
2008-09-28 2008-10-16 19 238d 2008-09-27 +1d
Unscheduled
2008-02-02 2008-02-03 2 288d - -
Scheduled
2007-02-25 2007-04-20 55 475d 2007-02-24 +1d
Scheduled
2005-10-09 2005-11-07 30 524d 2005-10-08 +1d
Scheduled
2004-03-28 2004-05-03 37 316d 2004-03-27 +1d
Unscheduled
2003-05-15 2003-05-17 3 59d - -
Unscheduled
2003-03-17 2003-03-17 1 94d - -
Unscheduled
2002-12-04 2002-12-13 10 8d - -
Unscheduled
2002-11-24 2002-11-26 3 7d - -
Unscheduled
2002-11-12 2002-11-17 6 2d - -
Scheduled
2002-09-28 2002-11-10 44 396d 2002-09-28 0d
Unscheduled
2001-08-19 2001-08-28 10 119d - -
Scheduled
2001-03-25 2001-04-22 29 513d 2001-03-25 0d
Scheduled
1999-09-25 1999-10-29 35 - 1999-09-25 0d
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