?
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.
33
Excellence
#74 of 94 →
Bottom Quartile
?
Days of continuous operation since the last outage ended. Clean run (no forced outages since last refueling).
15
Current Run
days ✔
?
Longest recorded period of continuous operation between outages (2020-04-05 to 2022-02-26).
692
Record Run
days
?
Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (618 days for this 24-month cycle unit) with no trips to 0% power.
3
B2B Runs
?
Lifetime capacity factor: average power level across all recorded days (100% = always at full power).
90.3%
Capacity Factor
?
Total number of scheduled refueling outages detected in the historical data.
14
Outages
since 2000
?
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.
7.3
Avg Startup
days (last 3)
?
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.
93.4%
Fuel Utilization
3yr avg
?
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
33/100
Bottom Quartile · #74/94
5-year window
Browns Ferry 3 ranks #74 of 94 active US units on NukeWorker's Operational Excellence Score over the 5-year window. Strongest area: Scrams (5-year) (70th percentile). Weakest: Startup Duration (7th percentile).
Reliability
35
Capacity factor + Forced outages + B2B streaks
Efficiency
26
Fuel utilization + Refuel duration
Discipline
38
Startup duration + Scram count
Cohort Rankings
apples-to-apples comparison within each peer group
Reactor type:
#22 of 31
BWR
Containment:
#15 of 19
Mark I (BWR)
Cycle length:
#31 of 40
24-month cycle
Fleet rank above (74 of 94) compares all active US units; cohort ranks compare only against units sharing this property.
Per-dimension breakdown (7 metrics)
Capacity Factor
23th
87.4% (higher better, Reliability)
Forced Outage Days/yr
13th
11.8d (lower better, Reliability)
B2B Avg Streak
69th
671d (higher better, Reliability)
Fuel Utilization
10th
94.1% (higher better, Efficiency)
Refuel Duration
42th
34d (lower better, Efficiency)
Startup Duration
7th
8.9d (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 Browns Ferry 3 head-to-head with up to 3 other units.
Compare now
?
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
?
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
?
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
?
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 Mar 28, 2026
94.0% remaining
46 / 698 days
4.2 FPD margin
Avg refuel: 6.2%
Avg refuel (3yr): 6.6%
Deepest burn: 2.7% (2016-03 → 2018-02)
Most margin: 13.9% (2012-05 → 2014-02)
?
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
|
2026-04-28 | 2026-04-29 | 2 | 33d | - | - |
|
Scheduled
|
2026-02-21 | 2026-03-26 | 34 | 196d | 2026-02-20 | +1d |
|
Unscheduled
|
2025-08-05 | 2025-08-09 | 5 | 154d | - | - |
|
Scram
# 57537
|
2025-02-09 | 2025-03-04 | 24 | 121d | - | - |
|
Unscheduled
|
2024-10-05 | 2024-10-11 | 7 | 197d | - | - |
|
Scheduled
|
2024-02-17 | 2024-03-22 | 35 | 294d | 2024-02-16 | +1d |
|
Unscheduled
|
2023-04-22 | 2023-04-29 | 8 | 132d | - | - |
|
Unscheduled
|
2022-12-03 | 2022-12-11 | 9 | 244d | - | - |
|
Unscheduled
|
2022-04-03 | 2022-04-03 | 1 | 2d | - | - |
|
Scheduled
|
2022-02-26 | 2022-04-01 | 35 | 692d | 2022-02-26 | 0d |
|
Unscheduled
|
2020-04-05 | 2020-04-05 | 1 | 2d | - | - |
|
Unscheduled
|
2020-04-02 | 2020-04-03 | 2 | 8d | - | - |
|
Scheduled
|
2020-02-22 | 2020-03-25 | 33 | 89d | 2020-02-22 | 0d |
|
Unscheduled
|
2019-11-16 | 2019-11-25 | 10 | 247d | - | - |
|
Scram
# 53923
|
2019-03-10 | 2019-03-14 | 5 | 133d | - | - |
|
Unscheduled
|
2018-10-22 | 2018-10-28 | 7 | 12d | - | - |
|
Unscheduled
|
2018-10-06 | 2018-10-10 | 5 | 184d | - | - |
|
Unscheduled
|
2018-04-04 | 2018-04-05 | 2 | 2d | - | - |
|
Scheduled
|
2018-02-17 | 2018-04-02 | 45 | 36d | 2018-02-17 | 0d |
|
Scram
# 53162
|
2018-01-11 | 2018-01-12 | 2 | 655d | - | - |
|
Scheduled
|
2016-02-20 | 2016-03-27 | 37 | 653d | 2016-02-19 | +1d |
|
Scram
# 50090
|
2014-05-07 | 2014-05-08 | 2 | 49d | - | - |
|
Scram
# 49928
|
2014-03-19 | 2014-03-19 | 1 | 3d | - | - |
|
Scheduled
|
2014-02-15 | 2014-03-16 | 30 | 352d | 2014-02-15 | 0d |
|
Scram
# 48782
|
2013-02-26 | 2013-02-28 | 3 | 6d | - | - |
|
Unscheduled
|
2013-02-12 | 2013-02-20 | 9 | 255d | - | - |
|
Scram
# 47972
|
2012-05-30 | 2012-06-02 | 4 | 7d | - | - |
|
Scram
# 47955
|
2012-05-22 | 2012-05-23 | 2 | 2d | - | - |
|
Scheduled
|
2012-04-07 | 2012-05-20 | 44 | 191d | 2012-04-07 | 0d |
|
Scram
# 47299
|
2011-09-29 | 2011-09-29 | 1 | 121d | - | - |
|
Scram
# 46793
|
2011-04-28 | 2011-05-31 | 34 | 112d | - | - |
|
Scram
# 46793
|
2011-04-28 | 2011-05-31 | 34 | 33d | - | - |
|
Scram
# 46793
|
2011-04-28 | 2011-05-31 | 34 | 33d | - | - |
|
Unscheduled
|
2010-12-27 | 2011-01-06 | 11 | 135d | - | - |
|
Unscheduled
|
2010-08-13 | 2010-08-14 | 2 | 127d | - | - |
|
Scheduled
|
2010-02-28 | 2010-04-08 | 40 | 123d | 2010-02-28 | 0d |
|
Unscheduled
|
2009-10-25 | 2009-10-28 | 4 | 37d | - | - |
|
Unscheduled
|
2009-09-13 | 2009-09-18 | 6 | 18d | - | - |
|
Unscheduled
|
2009-08-25 | 2009-08-26 | 2 | 409d | - | - |
|
Unscheduled
|
2008-07-11 | 2008-07-12 | 2 | 58d | - | - |
|
Scheduled
|
2008-03-19 | 2008-05-14 | 57 | 59d | 2008-03-17 | +2d |
|
Unscheduled
|
2008-01-10 | 2008-01-20 | 11 | 4d | - | - |
|
Unscheduled
|
2008-01-01 | 2008-01-06 | 6 | 26d | - | - |
|
Unscheduled
|
2007-12-01 | 2007-12-06 | 6 | 65d | - | - |
|
Unscheduled
|
2007-09-23 | 2007-09-27 | 5 | 223d | - | - |
|
Unscheduled
|
2007-02-10 | 2007-02-12 | 3 | 62d | - | - |
|
Unscheduled
|
2006-12-10 | 2006-12-10 | 1 | 101d | - | - |
|
Unscheduled
|
2006-08-30 | 2006-08-31 | 2 | 9d | - | - |
|
Unscheduled
|
2006-08-20 | 2006-08-21 | 2 | 151d | - | - |
|
Scheduled
|
2006-03-01 | 2006-03-22 | 22 | 40d | 2006-02-28 | +1d |
|
Unscheduled
|
2006-01-16 | 2006-01-20 | 5 | 68d | - | - |
|
Unscheduled
|
2005-11-01 | 2005-11-09 | 9 | 44d | - | - |
|
Unscheduled
|
2005-09-18 | 2005-09-18 | 1 | 215d | - | - |
|
Unscheduled
|
2005-02-12 | 2005-02-15 | 4 | 80d | - | - |
|
Unscheduled
|
2004-11-24 | 2004-11-24 | 1 | 239d | - | - |
|
Scheduled
|
2004-03-02 | 2004-03-30 | 29 | 245d | 2004-03-01 | +1d |
|
Unscheduled
|
2003-06-20 | 2003-07-01 | 12 | 437d | - | - |
|
Scheduled
|
2002-03-27 | 2002-04-09 | 14 | 671d | 2002-03-27 | 0d |
|
Unscheduled
|
2000-05-25 | 2000-05-25 | 1 | 22d | - | - |
|
Scheduled
|
2000-04-16 | 2000-05-03 | 18 | - | 2000-04-16 | 0d |
Page created in 0.088 seconds with 7 queries.