Surry 1 - Status & History

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

Plant Info Outage History Daily Power Log
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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.
46
Excellence
#57 of 94 ↓6
Mid Quartile
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Days of continuous operation since the last outage ended. Clean run (no forced outages since last refueling).
137
Current Run
days ✔
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Longest recorded period of continuous operation between outages (2021-05-31 to 2022-10-30).
517
Record Run
days
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (417 days for this 18-month cycle unit) with no trips to 0% power.
6
B2B Runs
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Lifetime capacity factor: average power level across all recorded days (100% = always at full power).
90.7%
Capacity Factor
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Total number of scheduled refueling outages detected in the historical data.
18
Outages
since 2000
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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
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.
99.0%
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
46/100
Mid Quartile · #57/94
5-year window

Surry 1 ranks #57 of 94 active US units on NukeWorker's Operational Excellence Score over the 5-year window. Strongest area: Fuel Utilization (92th percentile). Weakest: Refuel Duration (5th percentile).

Reliability
28
Capacity factor + Forced outages + B2B streaks
Efficiency
48
Fuel utilization + Refuel duration
Discipline
61
Startup duration + Scram count
Cohort Rankings apples-to-apples comparison within each peer group
Reactor type: #40 of 61 PWR
Containment: #4 of 5 Dry Subatmospheric (PWR)
Cycle length: #33 of 54 18-month cycle
Fleet rank above (57 of 94) compares all active US units; cohort ranks compare only against units sharing this property.
Per-dimension breakdown (7 metrics)
Capacity Factor 32th
89.1% (higher better, Reliability)
Forced Outage Days/yr 36th
5.2d (lower better, Reliability)
B2B Avg Streak 17th
499d (higher better, Reliability)
Fuel Utilization 92th
99.1% (higher better, Efficiency)
Refuel Duration 5th
57d (lower better, Efficiency)
Startup Duration 74th
3.5d (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: 2021: 53/100 (#49/93)2022: 52/100 (#47/92)2023: 54/100 (#39/92)2024: 42/100 (#62/93)2025: 30/100 (#77/94)2026: 27/100 (#83/94) ↓ -3.4 pts vs 2025
Compare Surry 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 Dec 30, 2025

73.0% remaining 134 / 493 days 1.0 FPD margin
Avg refuel: 1.1% Avg refuel (3yr): 1.0% Deepest burn: 0.0% (2000-05 → 2001-10) Most margin: 6.4% (2015-05 → 2016-10)
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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
Scheduled SGR/Major
2025-10-12 2025-12-28 78 63d 2025-10-12 0d
Scram # 57854
2025-08-07 2025-08-10 4 430d - -
Scheduled
2024-04-07 2024-06-03 58 478d 2024-04-06 +1d
Scheduled
2022-10-30 2022-12-16 48 517d 2022-10-23 +7d
Scheduled
2021-04-25 2021-05-31 37 513d 2021-04-25 0d
Scheduled
2019-10-19 2019-11-29 42 374d 2019-10-14 +5d
Unscheduled
2018-10-06 2018-10-10 5 129d - -
Scheduled
2018-04-21 2018-05-30 40 254d 2018-04-22 -1d
Unscheduled
2017-08-10 2017-08-10 1 273d - -
Scheduled
2016-10-22 2016-11-10 20 340d 2016-10-23 -1d
Scram # 51467
2015-10-14 2015-11-17 35 85d - -
Unscheduled
2015-07-11 2015-07-21 11 46d - -
Scheduled
2015-04-19 2015-05-26 38 515d 2015-04-19 0d
Scheduled
2013-10-20 2013-11-20 32 502d 2013-10-20 0d
Scheduled
2012-05-06 2012-06-05 31 379d 2012-04-22 +14d
Scram # 46761
2011-04-17 2011-04-23 7 137d - -
Scram # 46761
2011-04-17 2011-04-23 7 6d - -
Scheduled
2010-10-24 2010-12-01 39 135d 2010-10-24 0d
Unscheduled
2010-06-09 2010-06-11 3 395d - -
Scheduled
2009-04-19 2009-05-10 22 170d 2009-04-19 0d
Unscheduled
2008-10-28 2008-10-31 4 190d - -
Unscheduled
2008-04-17 2008-04-21 5 139d - -
Scheduled
2007-10-21 2007-11-30 41 287d 2007-10-21 0d
Unscheduled
2007-01-07 2007-01-07 1 228d - -
Scheduled
2006-04-23 2006-05-24 32 176d 2006-04-22 +1d
Unscheduled
2005-10-20 2005-10-29 10 254d - -
Unscheduled
2005-02-05 2005-02-08 4 65d - -
Scheduled
2004-11-01 2004-12-02 32 378d 2004-10-30 +2d
Unscheduled
2003-10-13 2003-10-20 8 22d - -
Unscheduled
2003-09-19 2003-09-21 3 99d - -
Scheduled
2003-04-20 2003-06-12 54 84d 2003-04-20 0d
Unscheduled
2003-01-26 2003-01-26 1 2d - -
Unscheduled
2003-01-14 2003-01-24 11 404d - -
Scheduled
2001-10-14 2001-12-06 54 161d 2001-10-14 0d
Unscheduled
2001-05-05 2001-05-06 2 192d - -
Unscheduled
2000-10-25 2000-10-25 1 169d - -
Scheduled
2000-04-16 2000-05-09 24 - 2000-04-16 0d
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