Byron 2

Refueling Outage · Day 19

Constellation Energy·Byron, IL·PWR·1,136 MWe

Outage History Daily Power Log Get alerts

Reactor Status Timeline

Refueling Outage · Day 19 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.
Nov2025DecJan2026FebMarAprMayJunJulAugSepOctOnline: Oct 16, 2025 to Sep 11, 2026Coastdown: Sep 12, 2026 to Sep 27, 2026Refueling Outage (B2R26): Sep 28, 2026 to Oct 16, 2026B2R26Today
OnlineCoastdownRefueling Outage
?
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
Rank locked · 93 units
Subscribers
?
Days of continuous operation since the last outage ended. Has forced outage(s) since last refueling.
--
Current Run
offline
?
Longest recorded period of continuous operation between outages (2020-10-19 to 2022-04-18).
546
Record Run
days
?
Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold set for this unit with no trips to 0% power.
12
B2B Runs
?
Lifetime capacity factor: average power level across all recorded days (100% = always at full power).
94.9%
Capacity Factor
?
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.
19.65 TWh
Net Generation
EIA-923 · 12 mo to 2026-07 · plant total
?
Total number of scheduled refueling outages detected in the historical data.
19
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.
3.7
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.
99.6%
Fuel Utilization
3yr avg

Reactor Status

Current Reactor Status Oct 16, 2026

?
Current power output from NRC daily reactor status reports, updated Monday through Friday, except federal holidays. The gauge shows power level as a percentage of rated capacity. The sparkline shows the last 14 days of power history. Click to view the full unit dashboard.
Byron 2 is OFFLINE (14 Days) at 0% of rated power as of Oct 16, 2026. This outage is RFO B2R26. Over the last 14 reported days it has run between 0% and 0% power.
Byron 2 is OFFLINE (14 Days) Get alerts
0
PERCENT
0 200 400 600 800 1000 1,136 RATED CAPACITY (1,136 MWe) 0 MWe
Current:
0 MWe
Powering 0 homes
Rated Capacity:
1,136 MWe
908,800 homes
14-Day Power History
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Oct 3 Oct 16

Capacity Factor (365-Day)

?
0%
Current
94.3%
365-Day Avg
#29
of 94 plants
Min: 0% Max: 100% 21 days <80%

Outage Days by Year

?
Total days spent in outage each year, split by scheduled refueling (blue) and forced/unplanned (red). Lower totals indicate better reliability and outage execution. Hover for details.
Across its recorded history, Byron 2 has spent 390 days in scheduled refueling outages and 34 days in forced or unplanned outages. Taller bars mark the years with the most downtime.
?
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

Byron 2 has 28 outages plotted here, averaging 15 days each. The most recent, in Sep 2026, was a scheduled refueling outage lasting 19 days.
?
Scheduled refueling outage durations over time. Green bars are at or below this unit's average, amber up to 30% above it, red beyond that. The dashed line is the average. Shorter outages mean better execution.

Refueling Duration Trend

Byron 2 has completed 19 scheduled refueling outages on record, averaging 21 days each. The most recent, in Sep 2026, ran 19 days.
?
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, Byron 2 takes about 3 days to climb from first power back to full power. That average is drawn from 18 startups on record, and the most recent took 4 days.
?
Daily reactor power over the 120 days before each scheduled refueling outage, one line per refueling, lined up on the day the outage began. A coastdown is the slow decline as the fuel runs out near the end of a cycle. The highlighted line is the most recent refueling and fainter lines are older. Counts and medians cover coastdowns of a week or longer. A shutdown straight from full power, with no decline ahead of it, is what a forced outage looks like.

Coastdown Before Refueling

12 of 19 refuelings 14 days median 86% power at shutdown 0.9% per day
Byron 2 coasted down for a week or longer before 12 of its 19 refuelings on record. Those coastdowns ran a median of 14 days and ended near 86% power. The most recent refueling, in Sep 2026, followed a 16-day coastdown from 97% to 82%.
?
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, Byron 2 has run at about 94.9% of its rated capacity. Across the last 12 reported months it averaged 90.3%. On the chart, green stretches near the top are full-power running, amber marks reduced power (50 to 89%), and red drops toward zero are outages.

Outage History & Daily Power Log

This table logs every recorded outage for Byron 2, 28 in all since 1999. Of those, 19 were scheduled refueling outages and 9 were unplanned or forced. The typical outage lasted about 15 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
Scheduled B2R26
2026-09-28 In Outage 19+ 515d 2026-09-28 0d
Scheduled B2R25
2025-04-14 2025-05-01 18 536d 2025-04-14 0d
Scheduled B2R24
2023-10-09 2023-10-26 18 516d 2023-10-09 0d
Scheduled B2R23
2022-04-18 2022-05-11 24 546d 2022-04-11 +7d
Scheduled B2R22
2020-10-05 2020-10-19 15 531d 2020-10-05 0d
Scheduled B2R21
2019-04-08 2019-04-23 16 534d 2019-04-08 0d
Scheduled B2R20
2017-10-02 2017-10-21 20 354d 2017-10-02 0d
Scram # 52295 Manual
2016-10-13 2016-10-13 1 150d - -
Scheduled B2R19
2016-04-18 2016-05-16 29 543d 2016-04-18 0d
Scheduled B2R18
2014-09-29 2014-10-23 25 518d 2014-09-29 0d
Scheduled B2R17
2013-04-08 2013-04-29 22 18d 2013-04-08 0d
Scram # 48838 Manual
2013-03-21 2013-03-21 1 408d - -
Scram # 47624 Auto
2012-01-31 2012-02-07 8 114d - -
Scheduled B2R16
2011-09-19 2011-10-09 21 116d 2011-09-19 0d
Unscheduled
2011-05-23 2011-05-26 4 381d - -
Scheduled B2R15
2010-04-19 2010-05-07 19 543d 2010-04-19 0d
Scheduled B2R14
2008-10-06 2008-10-23 18 342d 2008-10-06 0d
Unscheduled
2007-10-20 2007-10-30 11 171d - -
Scheduled B2R13
2007-04-02 2007-05-02 31 530d 2007-04-01 +1d
Unscheduled Startup Hold
2005-10-19 2005-10-19 1 7d - -
Scheduled B2R12
2005-09-26 2005-10-12 17 536d 2005-09-25 +1d
Scheduled B2R11
2004-03-23 2004-04-08 17 533d 2004-03-22 +1d
Scheduled B2R10
2002-09-17 2002-10-07 21 82d 2002-09-17 0d
Unscheduled
2002-06-23 2002-06-27 5 427d - -
Scheduled B2R9
2001-04-07 2001-04-22 16 254d 2001-04-07 0d
Unscheduled
2000-07-27 2000-07-27 1 195d - -
Unscheduled
2000-01-13 2000-01-14 2 59d - -
Scheduled B2R8
1999-10-23 1999-11-15 24 - 1999-10-23 0d
Working at Byron 2Jobs, per diem, lodging, directions, contact, ratings and photos.Work Here Specs, licensing & statisticsExcellence score, scram history, breaker-to-breaker record, specs, licensing and ownership.Specs & Stats
Page created in 0.274 seconds with 19 queries.