Sequoyah 2 - Status & History

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

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Reactor Status Timeline

Online NRC data, Mon to Fri ? Actual daily reactor status from NRC reports (Mon to Fri) and the current state. What is coming -- the utility's published Scheduled outage and NukeWorker's model Projection -- is part of a subscription. Colored by status. How far ahead you can see depends on your plan.
Oct2025NovDecJan2026FebMarAprMayJunJulAugSepOctOnline: Sep 20, 2025 to Nov 1, 2025Forced Outage: Nov 2, 2025 to Nov 8, 2025Power Ascension: Nov 9, 2025Online: Nov 10, 2025 to Sep 20, 2026Today
OnlinePower AscensionForced Outage
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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.
   
Excellence
ranked of 93
Subscribers
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Days of continuous operation since the last outage ended. Clean run (no forced outages since last refueling).
316
Current Run
days ✔
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Longest recorded period of continuous operation between outages (2000-11-14 to 2002-04-15).
517
Record Run
days
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold set for this unit with no trips to 0% power.
4
B2B Runs
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Lifetime capacity factor: average power level across all recorded days (100% = always at full power).
88.5%
Capacity Factor
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Net electricity actually generated over the most recent 12 months reported by the U.S. EIA (Form EIA-923), summed across every unit at this plant. Authoritative actuals, not an estimate.
17.87 TWh
Net Generation
EIA-923 · 12 mo to 2026-06 · plant total
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Total number of scheduled refueling outages detected in the historical data.
17
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.
17
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.
93.6%
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 measured 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
5-yr trend: 2021: 54/100 (#46/93)2022: 58/100 (#35/92)2023: 71/100 (#20/92)2024: 60/100 (#26/92)2025: 33/100 (#74/92)2026: 33/100 (#75/93) Stable vs 2025
Compare Sequoyah 2 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

Sequoyah 2 has 48 outages plotted here, averaging 15 days each. The most recent, in Nov 2025, was a unplanned outage lasting 7 days.
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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

After a refueling outage, Sequoyah 2 takes about 5 days to climb from first power back to full power. That average is drawn from 18 startups on record, and the most recent took 43 days.
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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 May 26, 2025

10.5% remaining 39.5 FPD margin
Sequoyah 2 has an estimated 10.5% of its fuel left. Across its last 17 cycles, it has refueled with an average of 1.6% remaining.
Avg refuel: 1.6% Avg refuel (3yr): 6.4% Deepest burn: 0.0% (1999-05 → 2000-10) Most margin: 6.4% (2023-04 → 2024-07)
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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

Over its operating life, Sequoyah 2 has run at about 88.5% of its rated capacity. Across the last 12 reported months it averaged 97.8%. On the chart, flat stretches near the top are full-power running and drops to zero are outages.
This table logs every recorded outage for Sequoyah 2, 49 in all since 1999. Of those, 18 were scheduled refueling outages and 31 were unplanned or forced. The typical outage lasted about 20 days. Where the Scheduled column shows (Model), the date is a NukeWorker projection because the utility had not published one.
Type ⇅ Actual Start ⇅ Actual End ⇅ Duration ⇅ Days Online ⇅ Scheduled Delta
Unscheduled
2025-11-02 2025-11-08 7 128d - -
Scram # 57779
2025-06-24 2025-06-27 4 5d - -
Unscheduled
2025-05-30 2025-06-19 21 6d - -
Unscheduled
2025-05-20 2025-05-24 5 3d - -
Scheduled # 57253 U2R26SGR/Major
2024-07-31 2025-05-17 291 4d 2024-08-07 -7d
Unscheduled
2024-07-21 2024-07-27 7 465d - -
Scheduled U2R25
2023-03-18 2023-04-13 27 496d 2023-03-18 0d
Scheduled U2R24
2021-10-02 2021-11-07 37 516d 2021-10-21 -19d
Scheduled U2R23
2020-04-11 2020-05-04 24 120d 2020-04-18 -7d
Scram # 54438
2019-12-13 2019-12-13 1 371d - -
Scheduled U2R22
2018-11-03 2018-12-07 35 516d 2018-09-29 +35d
Unscheduled
2017-06-05 2017-06-05 1 2d - -
Unscheduled
2017-06-03 2017-06-03 1 4d - -
Scheduled U2R21
2017-04-28 2017-05-30 33 355d 2017-04-22 +6d
Unscheduled
2016-05-07 2016-05-08 2 146d - -
Scheduled U2R20
2015-11-14 2015-12-13 30 253d 2015-11-16 -2d
Scram # 50856
2015-03-03 2015-03-06 4 263d - -
Scheduled U2R19
2014-05-12 2014-06-13 33 440d 2014-05-12 0d
Scram # 48778
2013-02-25 2013-02-26 2 54d - -
Scheduled U2R18SGR/Major
2012-10-15 2013-01-02 80 58d 2012-10-15 0d
Scram # 48198
2012-08-17 2012-08-18 2 422d - -
Scheduled U2R17
2011-05-23 2011-06-22 31 352d 2011-04-24 +29d
Unscheduled
2010-05-29 2010-06-05 8 184d - -
Unscheduled
2009-11-26 2009-11-26 1 2d - -
Scheduled U2R16
2009-10-26 2009-11-24 30 149d 2009-10-25 +1d
Unscheduled
2009-05-28 2009-05-30 3 61d - -
Unscheduled
2009-03-27 2009-03-28 2 135d - -
Unscheduled
2008-11-04 2008-11-12 9 64d - -
Unscheduled
2008-09-01 2008-09-01 1 89d - -
Scheduled U2R15
2008-05-05 2008-06-04 31 418d 2008-04-27 +8d
Unscheduled
2007-03-14 2007-03-14 1 49d - -
Unscheduled
2007-01-24 2007-01-24 1 30d - -
Scheduled U2R14
2006-11-27 2006-12-25 29 247d 2006-11-26 +1d
Unscheduled
2006-03-23 2006-03-25 3 300d - -
Scheduled U2R13
2005-04-25 2005-05-27 33 59d 2005-04-24 +1d
Unscheduled
2005-02-24 2005-02-25 2 396d - -
Unscheduled
2004-01-16 2004-01-25 10 9d - -
Unscheduled
2003-12-28 2004-01-07 11 18d - -
Scheduled U2R12
2003-11-10 2003-12-10 31 211d 2003-11-10 0d
Unscheduled
2003-04-13 2003-04-13 1 15d - -
Unscheduled
2003-03-25 2003-03-29 5 9d - -
Unscheduled
2003-03-11 2003-03-16 6 64d - -
Unscheduled
2002-12-27 2003-01-06 11 166d - -
Unscheduled
2002-07-13 2002-07-14 2 42d - -
Unscheduled
2002-05-31 2002-06-01 2 11d - -
Scheduled U2R11
2002-04-15 2002-05-20 36 517d 2002-04-15 0d
Scheduled U2R10
2000-10-23 2000-11-14 23 277d 2000-10-23 0d
Unscheduled
2000-01-19 2000-01-20 2 254d - -
Scheduled U2R9
1999-04-18 1999-05-10 23 - 1999-04-18 0d
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