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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.
18
Excellence
#90 of 94 ↑4
Bottom Quartile
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Days of continuous operation since the last outage ended. Clean run (no forced outages since last refueling).
173
Current Run
days ✔
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Longest recorded period of continuous operation between outages (2021-04-07 to 2023-02-11).
675
Record Run
days
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (606 days for this 24-month cycle unit) with no trips to 0% power.
1
B2B Runs
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Lifetime capacity factor: average power level across all recorded days (100% = always at full power).
86.4%
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.
15.7
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.
86.9%
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
18/100
Bottom Quartile · #90/94
5-year window
River Bend 1 ranks #90 of 94 active US units on NukeWorker's Operational Excellence Score over the 5-year window. Strongest area: B2B Avg Streak (70th percentile). Weakest: Startup Duration (5th percentile).
Reliability
36
Capacity factor + Forced outages + B2B streaks
Efficiency
8
Fuel utilization + Refuel duration
Discipline
10
Startup duration + Scram count
Cohort Rankings
apples-to-apples comparison within each peer group
Reactor type:
#29 of 31
BWR
Containment:
#3 of 4
Mark III (BWR)
Cycle length:
#38 of 40
24-month cycle
Fleet rank above (90 of 94) compares all active US units; cohort ranks compare only against units sharing this property.
Per-dimension breakdown (7 metrics)
Capacity Factor
16th
86.1% (higher better, Reliability)
Forced Outage Days/yr
22th
8.0d (lower better, Reliability)
B2B Avg Streak
70th
674d (higher better, Reliability)
Fuel Utilization
6th
93.1% (higher better, Efficiency)
Refuel Duration
9th
47d (lower better, Efficiency)
Startup Duration
5th
10.1d (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:
↑ +6.3 pts vs 2025
Compare River Bend 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 3, 2025
41.9% remaining
400 / 649 days
23.1 FPD margin
Avg refuel: 11.9%
Avg refuel (3yr): 13.1%
Deepest burn: 0.0% (2006-05 → 2009-09)
Most margin: 32.0% (2009-10 → 2011-01)
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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 |
|---|---|---|---|---|---|---|
|
Unscheduled
|
2025-11-12 | 2025-11-18 | 7 | 32d | - | - |
|
Scram
# 57975
|
2025-10-10 | 2025-10-11 | 2 | 138d | - | - |
|
Unscheduled
|
2025-05-22 | 2025-05-25 | 4 | 41d | - | - |
|
Scram
# 57655
|
2025-04-09 | 2025-04-11 | 3 | 10d | - | - |
|
Scheduled
|
2025-02-11 | 2025-03-30 | 48 | 424d | 2025-02-16 | -5d |
|
Scram
# 56887
|
2023-12-13 | 2023-12-15 | 3 | 23d | - | - |
|
Scram
# 56863
|
2023-11-18 | 2023-11-20 | 3 | 5d | - | - |
|
Unscheduled
|
2023-10-29 | 2023-11-13 | 16 | 136d | - | - |
|
Scheduled
SGR/Major
|
2023-02-11 | 2023-06-15 | 125 | 675d | 2023-02-18 | -7d |
|
Scram
# 55169
|
2021-04-03 | 2021-04-07 | 5 | 8d | - | - |
|
Scram
# 55154
|
2021-03-26 | 2021-03-26 | 1 | 7d | - | - |
|
Scheduled
|
2021-02-21 | 2021-03-19 | 27 | 106d | 2021-02-13 | +8d |
|
Unscheduled
|
2020-11-01 | 2020-11-07 | 7 | 68d | - | - |
|
Scram
# 54849
|
2020-08-22 | 2020-08-25 | 4 | 314d | - | - |
|
Unscheduled
|
2019-10-11 | 2019-10-13 | 3 | 127d | - | - |
|
Scram
# 54096
|
2019-06-01 | 2019-06-06 | 6 | 21d | - | - |
|
Scheduled
|
2019-03-30 | 2019-05-11 | 43 | 135d | 2019-03-31 | -1d |
|
Unscheduled
|
2018-11-15 | 2018-11-15 | 1 | 2d | - | - |
|
Scram
# 53732
|
2018-11-10 | 2018-11-13 | 4 | 249d | - | - |
|
Unscheduled
|
2018-03-02 | 2018-03-06 | 5 | 21d | - | - |
|
Scram
# 53192
|
2018-02-02 | 2018-02-09 | 8 | 3d | - | - |
|
Unscheduled
|
2018-01-08 | 2018-01-30 | 23 | 141d | - | - |
|
Scram
# 52915
|
2017-08-19 | 2017-08-20 | 2 | 55d | - | - |
|
Scram
# 52825
|
2017-06-24 | 2017-06-25 | 2 | 105d | - | - |
|
Scram
# 52602
|
2017-03-11 | 2017-03-11 | 1 | 3d | - | - |
|
Scheduled
|
2017-01-28 | 2017-03-08 | 40 | 218d | 2017-01-27 | +1d |
|
Unscheduled
|
2016-06-11 | 2016-06-24 | 14 | 102d | - | - |
|
Unscheduled
|
2016-02-18 | 2016-03-01 | 13 | 19d | - | - |
|
Scram
# 51644
|
2016-01-09 | 2016-01-30 | 22 | 38d | - | - |
|
Scram
# 51568
|
2015-11-28 | 2015-12-02 | 5 | 174d | - | - |
|
Scram
# 51112
|
2015-06-02 | 2015-06-07 | 6 | 67d | - | - |
|
Scheduled
|
2015-02-23 | 2015-03-27 | 33 | 58d | 2015-02-16 | +7d |
|
Scram
# 50704
|
2014-12-26 | 2014-12-27 | 2 | 65d | - | - |
|
Scram
# 50546
|
2014-10-17 | 2014-10-22 | 6 | 485d | - | - |
|
Unscheduled
|
2013-06-17 | 2013-06-19 | 3 | 91d | - | - |
|
Scheduled
|
2013-02-17 | 2013-03-18 | 30 | 254d | 2013-02-17 | 0d |
|
Unscheduled
|
2012-06-03 | 2012-06-08 | 6 | 2d | - | - |
|
Scram
# 47960
|
2012-05-25 | 2012-06-01 | 8 | 2d | - | - |
|
Scram
# 47960
|
2012-05-22 | 2012-05-23 | 2 | 14d | - | - |
|
Unscheduled
|
2012-05-04 | 2012-05-08 | 5 | 131d | - | - |
|
Scram
# 47549
|
2011-12-24 | 2011-12-25 | 2 | 317d | - | - |
|
Scheduled
|
2011-01-15 | 2011-02-10 | 27 | 164d | 2011-01-16 | -1d |
|
Unscheduled
|
2010-07-31 | 2010-08-04 | 5 | 287d | - | - |
|
Scheduled
|
2009-09-21 | 2009-10-17 | 27 | 365d | 2009-09-25 | -4d |
|
Unscheduled
|
2008-09-02 | 2008-09-21 | 20 | 164d | - | - |
|
Unscheduled
|
2008-03-21 | 2008-03-22 | 2 | 15d | - | - |
|
Unscheduled
|
2008-03-06 | 2008-03-06 | 1 | 5d | - | - |
|
Unscheduled
|
2008-01-07 | 2008-03-01 | 55 | 58d | - | - |
|
Unscheduled
|
2007-11-07 | 2007-11-10 | 4 | 35d | - | - |
|
Unscheduled
|
2007-09-27 | 2007-10-03 | 7 | 111d | - | - |
|
Unscheduled
|
2007-05-23 | 2007-06-08 | 17 | 17d | - | - |
|
Unscheduled
|
2007-05-05 | 2007-05-06 | 2 | 196d | - | - |
|
Unscheduled
|
2006-10-19 | 2006-10-21 | 3 | 160d | - | - |
|
Scheduled
|
2006-04-24 | 2006-05-12 | 19 | 7d | 2006-04-23 | +1d |
|
Unscheduled
|
2006-04-16 | 2006-04-17 | 2 | 58d | - | - |
|
Unscheduled
|
2006-02-11 | 2006-02-17 | 7 | 224d | - | - |
|
Unscheduled
|
2005-07-02 | 2005-07-02 | 1 | 2d | - | - |
|
Unscheduled
|
2005-06-23 | 2005-06-30 | 8 | 110d | - | - |
|
Unscheduled
|
2005-03-01 | 2005-03-05 | 5 | 4d | - | - |
|
Unscheduled
|
2005-02-20 | 2005-02-25 | 6 | 36d | - | - |
|
Unscheduled
|
2005-01-15 | 2005-01-15 | 1 | 35d | - | - |
|
Unscheduled
|
2004-12-11 | 2004-12-11 | 1 | 23d | - | - |
|
Scheduled
|
2004-10-22 | 2004-11-18 | 28 | 16d | 2004-10-21 | +1d |
|
Unscheduled
|
2004-10-02 | 2004-10-06 | 5 | 47d | - | - |
|
Unscheduled
|
2004-08-15 | 2004-08-16 | 2 | 327d | - | - |
|
Unscheduled
|
2003-09-23 | 2003-09-23 | 1 | 166d | - | - |
|
Scheduled
|
2003-03-17 | 2003-04-10 | 25 | 22d | 2003-03-17 | 0d |
|
Unscheduled
|
2003-02-22 | 2003-02-23 | 2 | 155d | - | - |
|
Unscheduled
|
2002-09-19 | 2002-09-20 | 2 | 79d | - | - |
|
Unscheduled
|
2002-07-02 | 2002-07-02 | 1 | 48d | - | - |
|
Unscheduled
|
2002-05-13 | 2002-05-15 | 3 | 196d | - | - |
|
Unscheduled
|
2001-10-27 | 2001-10-29 | 3 | 17d | - | - |
|
Scheduled
|
2001-09-24 | 2001-10-10 | 17 | 154d | 2001-09-24 | 0d |
|
Unscheduled
|
2001-04-22 | 2001-04-23 | 2 | 2d | - | - |
|
Unscheduled
|
2001-04-18 | 2001-04-20 | 3 | 236d | - | - |
|
Unscheduled
|
2000-08-22 | 2000-08-25 | 4 | 137d | - | - |
|
Scheduled
|
2000-03-04 | 2000-04-07 | 35 | 126d | 2000-03-04 | 0d |
|
Unscheduled
|
1999-10-30 | 1999-10-30 | 1 | 122d | - | - |
|
Unscheduled
|
1999-04-03 | 1999-06-30 | 89 | - | - | - |
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