LaSalle 1 - Status & History

Comprehensive reactor performance metrics, cycle analysis, and historical outage data.
Data refreshed 9h ago Rx Status: Sep 17, 2026 at 7:49 AM (M-F)

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 17, 2025 to Oct 18, 2025Reduced Power: Oct 19, 2025Online: Oct 20, 2025 to Nov 2, 2025Scram: Nov 3, 2025 to Nov 4, 2025Reduced Power: Nov 5, 2025 to Nov 6, 2025Online: Nov 7, 2025 to Dec 3, 2025Reduced Power: Dec 4, 2025 to Dec 5, 2025Online: Dec 6, 2025 to Dec 25, 2025Coastdown: Dec 26, 2025 to Dec 28, 2025Scram: Dec 29, 2025 to Dec 31, 2025Coastdown: Jan 1, 2026Power Ascension: Jan 2, 2026 to Jan 8, 2026Coastdown: Jan 9, 2026Power Ascension: Jan 10, 2026 to Jan 11, 2026Coastdown: Jan 12, 2026 to Jan 15, 2026Power Ascension: Jan 16, 2026Coastdown: Jan 17, 2026 to Jan 19, 2026Power Ascension: Jan 20, 2026 to Jan 21, 2026Coastdown: Jan 22, 2026 to Feb 8, 2026Refueling Outage (L1R21): Feb 9, 2026 to Feb 27, 2026L1R21Power Ascension: Feb 28, 2026 to Mar 1, 2026Online: Mar 2, 2026 to Mar 13, 2026Reduced Power: Mar 14, 2026 to Mar 16, 2026Online: Mar 17, 2026 to May 2, 2026Reduced Power: May 3, 2026Online: May 4, 2026 to May 25, 2026Reduced Power: May 26, 2026Forced Outage: May 27, 2026 to May 30, 2026Reduced Power: May 31, 2026Online: Jun 1, 2026Power Ascension: Jun 2, 2026Online: Jun 3, 2026 to Sep 17, 2026Scram (reactor trip): Nov 2, 2025Scram (reactor trip): Dec 28, 2025Today
OnlineReduced PowerCoastdownPower AscensionRefueling OutageForced OutageScramScram (reactor trip)
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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 (Started 2026-05-30). Clean run (no forced outages since last refueling).
110
Current Run
days ✔
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Longest recorded period of continuous operation between outages (2004-02-11 to 2006-02-20).
740
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).
94.1%
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.
18.49 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.
13
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.
3
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.
97.2%
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: 70/100 (#22/93)2022: 88/100 (#4/92)2023: 90/100 (#4/92)2024: 93/100 (#2/92)2025: 72/100 (#20/92)2026: 73/100 (#19/93) Stable vs 2025
Compare LaSalle 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

LaSalle 1 has 34 outages plotted here, averaging 12 days each. The most recent, in May 2026, was a unplanned outage lasting 4 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, LaSalle 1 takes about 4 days to climb from first power back to full power. That average is drawn from 13 startups on record, and the most recent took 2 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 Feb 28, 2026

72.5% remaining 7.3 FPD margin
LaSalle 1 has an estimated 72.5% of its fuel left. Across its last 12 cycles, it has refueled with an average of 2.0% remaining.
Avg refuel: 2.0% Avg refuel (3yr): 2.8% Deepest burn: 0.0% (2004-02 → 2006-02) Most margin: 5.1% (2006-03 → 2008-02)
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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, LaSalle 1 has run at about 94.1% of its rated capacity. Across the last 12 reported months it averaged 88.5%. 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 LaSalle 1, 34 in all since 1999. Of those, 13 were scheduled refueling outages and 21 were unplanned or forced. The typical outage lasted about 12 days. Where the Scheduled column shows (Model), the date is a NukeWorker projection because the utility had not published one.
Unscheduled
2026-05-27 2026-05-30 4 89d - -
Scheduled L1R21
2026-02-09 2026-02-27 19 40d 2026-02-09 0d
Scram # 58100
2025-12-29 2025-12-31 3 55d - -
Scram # 58018
2025-11-03 2025-11-04 2 605d - -
Scheduled L1R20
2024-02-19 2024-03-08 19 704d 2024-02-19 0d
Scheduled L1R19
2022-02-21 2022-03-17 25 725d 2022-02-21 0d
Scheduled L1R18
2020-02-10 2020-02-27 18 43d 2020-02-10 0d
Unscheduled
2019-12-27 2019-12-29 3 643d - -
Unscheduled
2018-03-23 2018-03-24 2 10d - -
Scheduled L1R17
2018-02-19 2018-03-13 23 238d 2018-02-19 0d
Unscheduled
2017-06-24 2017-06-26 3 125d - -
Scram # 52564
2017-02-18 2017-02-19 2 3d - -
Scram # 52547
2017-02-14 2017-02-15 2 330d - -
Unscheduled
2016-03-20 2016-03-21 2 5d - -
Unscheduled Startup Hold
2016-03-12 2016-03-15 4 4d - -
Scheduled L1R16
2016-02-15 2016-03-08 23 484d 2016-02-15 0d
Unscheduled
2014-10-12 2014-10-19 8 227d - -
Scheduled L1R15
2014-02-10 2014-02-27 18 287d 2014-02-10 0d
Scram # 48939
2013-04-18 2013-04-29 12 408d - -
Scheduled L1R14
2012-02-13 2012-03-06 23 367d 2012-02-13 0d
Scram # 46582
2011-02-02 2011-02-11 10 333d - -
Scheduled L1R13
2010-02-08 2010-03-06 27 202d 2010-02-08 0d
Unscheduled
2009-07-19 2009-07-21 3 57d - -
Unscheduled
2009-05-22 2009-05-23 2 233d - -
Unscheduled
2008-09-30 2008-10-01 2 216d - -
Scheduled L1R12
2008-02-04 2008-02-27 24 689d 2008-02-04 0d
Scheduled L1R11
2006-02-20 2006-03-17 26 740d 2006-02-20 0d
Scheduled L1R10
2004-01-13 2004-02-11 30 46d 2004-01-13 0d
Unscheduled
2003-11-27 2003-11-28 2 551d - -
Unscheduled
2002-05-18 2002-05-25 8 104d - -
Scheduled L1R9
2002-01-11 2002-02-03 24 343d 2002-01-11 0d
Unscheduled
2001-02-01 2001-02-02 2 439d - -
Unscheduled
1999-10-23 1999-11-20 29 49d - -
Unscheduled
1999-09-03 1999-09-04 2 - - -
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