Peach Bottom 3 - 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.
89
Excellence
#2 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).
193
Current Run
days ✔
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Longest recorded period of continuous operation between outages (2015-10-21 to 2017-10-23).
733
Record Run
days
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (628 days for this 24-month cycle unit) with no trips to 0% power.
9
B2B Runs
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Lifetime capacity factor: average power level across all recorded days (100% = always at full power).
94.5%
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.
1.7
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.
98.6%
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
89/100
Top Quartile · #2/94
5-year window

Peach Bottom 3 ranks #2 of 94 active US units on NukeWorker's Operational Excellence Score over the 5-year window. Strongest area: B2B Avg Streak (97th percentile). Weakest: Fuel Utilization (66th percentile).

Reliability
96
Capacity factor + Forced outages + B2B streaks
Efficiency
77
Fuel utilization + Refuel duration
Discipline
92
Startup duration + Scram count
Cohort Rankings apples-to-apples comparison within each peer group
Reactor type: #1 of 31 BWR
Containment: #1 of 19 Mark I (BWR)
Cycle length: #2 of 40 24-month cycle
Fleet rank above (2 of 94) compares all active US units; cohort ranks compare only against units sharing this property.
Per-dimension breakdown (7 metrics)
Capacity Factor 96th
96.4% (higher better, Reliability)
Forced Outage Days/yr 95th
0.6d (lower better, Reliability)
B2B Avg Streak 97th
711d (higher better, Reliability)
Fuel Utilization 66th
98.3% (higher better, Efficiency)
Refuel Duration 88th
20d (lower better, Efficiency)
Startup Duration 94th
2.9d (lower better, Discipline)
Scrams (5-year) 90th
0.0/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: 83/100 (#6/93)2022: 85/100 (#6/92)2023: 95/100 (#1/92)2024: 94/100 (#1/93)2025: 91/100 (#1/94)2026: 92/100 (#1/94) Stable vs 2025
Compare Peach Bottom 3 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 Nov 3, 2025

73.6% remaining 190 / 714 days 1.3 FPD margin
Avg refuel: 3.3% Avg refuel (3yr): 1.4% Deepest burn: 0.4% (2015-10 → 2017-10) Most margin: 7.7% (1999-10 → 2001-09)
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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
2025-10-13 2025-11-02 21 716d 2025-10-20 -7d
Scheduled
2023-10-16 2023-10-28 13 709d 2023-10-16 0d
Scheduled
2021-10-25 2021-11-06 13 720d 2021-10-18 +7d
Scheduled
2019-10-21 2019-11-05 16 377d 2019-10-21 0d
Scram # 53630
2018-10-01 2018-10-09 9 6d - -
Unscheduled
2018-09-23 2018-09-25 3 321d - -
Scheduled
2017-10-23 2017-11-06 15 733d 2017-10-23 0d
Scheduled
2015-09-21 2015-10-21 31 704d 2015-09-13 +8d
Scheduled
2013-09-09 2013-10-17 39 697d 2013-09-08 +1d
Scheduled
2011-09-12 2011-10-13 32 298d 2011-09-11 +1d
Unscheduled
2010-11-16 2010-11-18 3 400d - -
Scheduled
2009-09-14 2009-10-12 29 231d 2009-09-13 +1d
Unscheduled
2009-01-22 2009-01-26 5 351d - -
Unscheduled
2008-02-06 2008-02-06 1 116d - -
Scheduled
2007-09-24 2007-10-13 20 709d 2007-09-23 +1d
Scheduled
2005-09-20 2005-10-15 26 710d 2005-09-19 +1d
Scheduled
2003-09-15 2003-10-11 27 707d 2003-09-15 0d
Scheduled
2001-09-15 2001-10-08 24 402d 2001-09-15 0d
Unscheduled
2000-08-08 2000-08-09 2 288d - -
Scheduled
1999-09-30 1999-10-25 26 - 1999-09-30 0d
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