?
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.
42
Excellence
#64 of 94 ↓26
Mid Quartile
?
Days of continuous operation since the last outage ended. Clean run (no forced outages since last refueling).
196
Current Run
days ✔
?
Longest recorded period of continuous operation between outages (2007-04-11 to 2009-04-07).
727
Record Run
days
?
Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (584 days for this 24-month cycle unit) with no trips to 0% power.
4
B2B Runs
?
Lifetime capacity factor: average power level across all recorded days (100% = always at full power).
89.4%
Capacity Factor
?
Total number of scheduled refueling outages detected in the historical data.
14
Outages
since 1999
?
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.
98.6%
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
42/100
Mid Quartile · #64/94
5-year window
Susquehanna 2 ranks #64 of 94 active US units on NukeWorker's Operational Excellence Score over the 5-year window. Strongest area: B2B Avg Streak (90th percentile). Weakest: Refuel Duration (2th percentile).
Reliability
67
Capacity factor + Forced outages + B2B streaks
Efficiency
31
Fuel utilization + Refuel duration
Discipline
29
Startup duration + Scram count
Cohort Rankings
apples-to-apples comparison within each peer group
Reactor type:
#19 of 31
BWR
Containment:
#6 of 8
Mark II (BWR)
Cycle length:
#27 of 40
24-month cycle
Fleet rank above (64 of 94) compares all active US units; cohort ranks compare only against units sharing this property.
Per-dimension breakdown (7 metrics)
Capacity Factor
47th
90.7% (higher better, Reliability)
Forced Outage Days/yr
63th
2.6d (lower better, Reliability)
B2B Avg Streak
90th
705d (higher better, Reliability)
Fuel Utilization
60th
98.2% (higher better, Efficiency)
Refuel Duration
2th
71d (lower better, Efficiency)
Startup Duration
9th
8.2d (lower better, Discipline)
Scrams (5-year)
48th
0.4/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:
↓ -12.8 pts vs 2025
Compare Susquehanna 2 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 Jun 5, 2025
52.7% remaining
342 / 699 days
11.5 FPD margin
Avg refuel: 6.4%
Avg refuel (3yr): 1.4%
Deepest burn: 0.0% (2007-04 → 2009-04)
Most margin: 18.0% (2011-07 → 2013-04)
?
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
# 58012
|
2025-10-29 | 2025-10-30 | 2 | 148d | - | - |
|
Scheduled
|
2025-03-24 | 2025-06-03 | 72 | 702d | 2025-03-28 | -4d |
|
Scheduled
|
2023-03-20 | 2023-04-22 | 34 | 63d | 2023-03-20 | 0d |
|
Unscheduled
|
2023-01-15 | 2023-01-16 | 2 | 105d | - | - |
|
Unscheduled
|
2022-09-29 | 2022-10-02 | 4 | 350d | - | - |
|
Scram
# 55514
|
2021-10-12 | 2021-10-14 | 3 | 173d | - | - |
|
Scheduled
|
2021-03-22 | 2021-04-22 | 32 | 401d | 2021-03-20 | +2d |
|
Scram
# 54525
|
2020-02-14 | 2020-02-15 | 2 | 300d | - | - |
|
Scheduled
|
2019-03-23 | 2019-04-20 | 29 | 714d | 2019-03-23 | 0d |
|
Scheduled
|
2017-03-04 | 2017-04-08 | 36 | 149d | 2017-03-04 | 0d |
|
Unscheduled
|
2016-10-02 | 2016-10-06 | 5 | 139d | - | - |
|
Scram
# 51925
|
2016-05-13 | 2016-05-16 | 4 | 356d | - | - |
|
Scheduled
|
2015-04-11 | 2015-05-23 | 43 | 210d | 2015-04-11 | 0d |
|
Unscheduled
|
2014-09-06 | 2014-09-13 | 8 | 64d | - | - |
|
Unscheduled
|
2014-06-26 | 2014-07-04 | 9 | 94d | - | - |
|
Unscheduled
|
2014-03-21 | 2014-03-24 | 4 | 7d | - | - |
|
Unscheduled
|
2014-03-02 | 2014-03-14 | 13 | 161d | - | - |
|
Scram
# 49342
|
2013-09-14 | 2013-09-22 | 9 | 109d | - | - |
|
Scheduled
|
2013-04-14 | 2013-05-28 | 45 | 109d | 2013-04-15 | -1d |
|
Scram
# 48607
|
2012-12-20 | 2012-12-26 | 7 | 2d | - | - |
|
Scram
# 48607
|
2012-12-16 | 2012-12-18 | 3 | 18d | - | - |
|
Unscheduled
|
2012-11-28 | 2012-11-28 | 1 | 3d | - | - |
|
Unscheduled
|
2012-11-21 | 2012-11-25 | 5 | 3d | - | - |
|
Scram
# 48496
|
2012-11-09 | 2012-11-18 | 10 | 149d | - | - |
|
Unscheduled
|
2012-05-31 | 2012-06-13 | 14 | 284d | - | - |
|
Scram
# 47172
|
2011-08-20 | 2011-08-21 | 2 | 55d | - | - |
|
Scheduled
SGR/Major
|
2011-04-05 | 2011-06-26 | 83 | 346d | 2011-04-05 | 0d |
|
Unscheduled
|
2010-04-24 | 2010-04-24 | 1 | 344d | - | - |
|
Scheduled
|
2009-04-07 | 2009-05-15 | 39 | 727d | 2009-04-07 | 0d |
|
Scheduled
|
2007-03-04 | 2007-04-11 | 39 | 138d | 2007-03-03 | +1d |
|
Unscheduled
|
2006-09-30 | 2006-10-17 | 18 | 149d | - | - |
|
Unscheduled
|
2006-04-29 | 2006-05-04 | 6 | 323d | - | - |
|
Unscheduled
|
2005-06-07 | 2005-06-10 | 4 | 39d | - | - |
|
Unscheduled
|
2005-04-29 | 2005-04-29 | 1 | 17d | - | - |
|
Unscheduled
|
2005-04-11 | 2005-04-12 | 2 | 20d | - | - |
|
Scheduled
|
2005-02-27 | 2005-03-22 | 24 | 680d | 2005-02-26 | +1d |
|
Scheduled
|
2003-03-08 | 2003-04-19 | 43 | 147d | 2003-03-08 | 0d |
|
Unscheduled
|
2002-10-01 | 2002-10-12 | 12 | 527d | - | - |
|
Scheduled
|
2001-03-10 | 2001-04-22 | 44 | 199d | 2001-03-10 | 0d |
|
Unscheduled
|
2000-08-18 | 2000-08-23 | 6 | 240d | - | - |
|
Unscheduled
|
1999-12-18 | 1999-12-22 | 5 | 186d | - | - |
|
Unscheduled
|
1999-06-09 | 1999-06-15 | 7 | 44d | - | - |
|
Unscheduled
|
1999-04-26 | 1999-04-26 | 1 | 2d | - | - |
|
Scheduled
|
1999-03-13 | 1999-04-24 | 43 | - | 1999-03-13 | 0d |
Page created in 0.090 seconds with 7 queries.