Braidwood 1 - Status & History

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

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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.
71
Excellence
#19 of 94
Top Quartile
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Days of continuous operation since the last outage ended. Clean run (no forced outages since last refueling).
204
Current Run
days ✔
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Longest recorded period of continuous operation between outages (2001-10-11 to 2003-04-15).
551
Record Run
days
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (468 days for this 18-month cycle unit) with no trips to 0% power.
13
B2B Runs
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Lifetime capacity factor: average power level across all recorded days (100% = always at full power).
95%
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.
4.7
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.
97.6%
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.
Time window — change how far back we look
NukeWorker's
Operational
Excellence Score
71/100
Top Quartile · #19/94
5-year window

Braidwood 1 ranks #19 of 94 active US units on NukeWorker's Operational Excellence Score over the 5-year window. Strongest area: Refuel Duration (97th percentile). Weakest: Scrams (5-year) (30th percentile).

Reliability
77
Capacity factor + Forced outages + B2B streaks
Efficiency
89
Fuel utilization + Refuel duration
Discipline
48
Startup duration + Scram count
Cohort Rankings apples-to-apples comparison within each peer group
Reactor type: #10 of 61 PWR
Containment: #8 of 48 Dry Ambient (PWR)
Cycle length: #7 of 54 18-month cycle
Fleet rank above (19 of 94) compares all active US units; cohort ranks compare only against units sharing this property.
Per-dimension breakdown (7 metrics)
Capacity Factor 90th
95.6% (higher better, Reliability)
Forced Outage Days/yr 87th
1.0d (lower better, Reliability)
B2B Avg Streak 53th
520d (higher better, Reliability)
Fuel Utilization 80th
98.7% (higher better, Efficiency)
Refuel Duration 97th
17d (lower better, Efficiency)
Startup Duration 67th
3.8d (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: 60/100 (#33/93)2022: 60/100 (#31/92)2023: 73/100 (#15/92)2024: 72/100 (#16/93)2025: 67/100 (#23/94)2026: 68/100 (#23/94) Stable vs 2025
Compare Braidwood 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 23, 2025

61.8% remaining 202 / 526 days 1.0 FPD margin
Avg refuel: 1.5% Avg refuel (3yr): 2.4% Deepest burn: 0.0% (2001-10 → 2003-04) Most margin: 9.8% (2012-05 → 2013-09)
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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

Scheduled
2025-10-06 2025-10-22 17 67d 2025-10-06 0d
Scram # 57839
2025-07-31 2025-07-31 1 452d - -
Scheduled
2024-04-15 2024-05-05 21 543d 2024-04-14 +1d
Scheduled
2022-10-03 2022-10-20 18 469d 2022-10-03 0d
Scram # 55320
2021-06-21 2021-06-21 1 59d - -
Scheduled
2021-04-05 2021-04-23 19 531d 2021-04-05 0d
Scheduled
2019-10-07 2019-10-22 16 489d 2019-10-01 +6d
Scram # 53443
2018-06-05 2018-06-05 1 38d - -
Scheduled
2018-04-09 2018-04-28 20 532d 2018-04-09 0d
Scheduled
2016-09-26 2016-10-24 29 528d 2016-09-26 0d
Scheduled
2015-03-30 2015-04-17 19 546d 2015-03-30 0d
Scheduled
2013-09-09 2013-09-30 22 478d 2013-09-09 0d
Scheduled
2012-04-16 2012-05-19 34 528d 2012-04-16 0d
Scheduled
2010-10-04 2010-11-05 33 13d 2010-10-04 0d
Unscheduled
2010-09-21 2010-09-21 1 32d - -
Unscheduled
2010-08-16 2010-08-20 5 484d - -
Scheduled
2009-03-30 2009-04-19 21 522d 2009-04-06 -7d
Scheduled
2007-10-01 2007-10-25 25 95d 2007-10-01 0d
Unscheduled
2007-06-28 2007-06-28 1 421d - -
Scheduled
2006-04-17 2006-05-03 17 213d 2006-04-16 +1d
Unscheduled
2005-09-12 2005-09-16 5 323d - -
Scheduled
2004-10-05 2004-10-24 20 523d 2004-10-04 +1d
Scheduled
2003-04-15 2003-05-01 17 551d 2003-04-15 0d
Scheduled
2001-09-22 2001-10-11 20 535d 2001-09-22 0d
Scheduled
2000-03-18 2000-04-05 19 345d 2000-03-18 0d
Unscheduled
1999-04-06 1999-04-08 3 - - -
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