Arkansas Nuclear 1
Online · 100% powerEntergy·Russellville, AR·PWR·833 MWe
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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
Rank locked · 93 units
Subscribers
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Current reactor power level from the most recent NRC daily report.
100%
Power
ONLINE
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Days of continuous operation since the last outage ended. Ranked against all operating units.
362
Current Run
days
#17 of 95
Top Quartile
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Longest recorded period of continuous operation between outages.
573
Record Run
days
#54 of 95
Mid Quartile
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (456 days for this 18-month cycle unit) with no trips to 0% power.
6
B2B Runs
79% toward B2B (360/456d)
#30 of 85
Mid Quartile
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Lifetime capacity factor: average power level across all recorded days (100% = always at full power). Ranked against all NRC-tracked units.
88.6%
Capacity Factor
#67 of 95
Mid Quartile
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Net electricity actually generated over the most recent 12 months reported by the U.S. Energy Information Administration (Form EIA-923), summed across every unit at this plant. These are authoritative actuals, not an estimate.
14.09 TWh
Net Generation
EIA-923 · 12 mo to 2026-08 · plant total
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Total NRC-reported scram events (emergency reactor shutdowns). Ranked fleet-wide — fewer scrams = better rank.
9
Scrams
#64 of 94
Mid Quartile
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Years since commercial operation began. License remaining: 7.5 years.
51.9
Operating Age
years
7.5 yrs remaining
Excellence Score, Records & Plant Facts
Breaker-to-Breaker Runs 6 runs
Breaker-to-breaker runs measure continuous operation between refueling outages using a cycle-adjusted threshold (90% of cycle length minus RFO duration). An active streak means the unit has been running continuously since the last refueling with no trips to 0% power.
Arkansas Nuclear 1 has logged 6 breaker-to-breaker runs, continuous stretches from one refueling to the next with no trip to zero power. Its longest ran 538 days, and its runs average 506 days.
538
Best Run (days)
1R22 (2010-04-27) → 1R23 (2011-10-17)
506
Avg Run (days)
★ Triple breaker-to-breaker
1R18 → 1R19 → 1R20 → 1R21
All Runs
| 2013-08-17 | 2015-01-26 | 527 days | 1R24 → 1R25 |
| 2011-11-21 | 2013-03-25 | 490 days | 1R23 → 1R24 |
| 2010-04-27 | 2011-10-17 | 538 days | 1R22 → 1R23 |
| 2007-05-14 | 2008-10-27 | 532 days | 1R20 → 1R21 |
| 2005-12-30 | 2007-04-23 | 479 days | 1R19 → 1R20 |
| 2004-06-20 | 2005-10-05 | 472 days | 1R18 → 1R19 |
About This Site
Written by NukeWorker from public records: facts that do not change. Operator, status and capacity come from the live data elsewhere on this page. Sources: Wikipedia: Arkansas Nuclear One.
Arkansas Nuclear One is a two-unit nuclear power station in Pope County, Arkansas, near Russellville, on the northeast shore of Lake Dardanelle.
Read more
Construction began on Unit 1 on October 1, 1968, and on Unit 2 on December 6, 1968. Unit 1, a Babcock & Wilcox pressurized water reactor, was first connected to the grid on August 17, 1974, and entered commercial operation that December. Unit 2, supplied by Combustion Engineering, was connected on December 26, 1978. On March 31, 2013, a generator stator fell during a replacement operation at Unit 1, killing one worker and cutting power to Unit 1 and part of Unit 2.
Facility Statistics
Key performance and lifecycle metrics calculated from NRC operational data. Includes operating age, construction timeline, capacity factor, efficiency, generation totals, and reliability records.
Arkansas Nuclear 1 has operated for about 51.9 years and averaged a 88.6% lifetime capacity factor, generating roughly 182.1 TWh of electricity. Its longest unbroken run reached 573 days.
Lifecycle & Tenure
Operating Age: 51.9 Yrs
Build Time: 6 Yrs
Lic. Remaining: 7.5 Yrs
Production & Power
Lifetime CF: 88.6%
Efficiency: 32.4%
Generated: 182.1 TWh
Reliability & Outages
Record Run: 573 Days
Refuelings: 18
Avg Startup: 7.3 Days
Ownership & Construction
The utility or company that owns and operates the facility, the architect-engineer responsible for plant design, and the primary construction contractor. Click names to view all facilities by that entity on the map.
Ownership, operation and management history
No change of owner, operator or management company on record. Our history starts in 1999.
ETR
Entergy Corporation
NYSE
$111.71
▼ -0.09 (-0.08%)
Previous Close
111.79
Day's Range
110.31 – 111.76
52-Week Range
90.87 – 118.45
Volume
1,304,179
Delayed quote as of Nov 10, 2026 3:56 PM ET.
Source: Yahoo Finance.
Full quote on Yahoo Finance
Operational Excellence Score Subscribers
Arkansas Nuclear 1 is rated 0 to 100 on how well it actually runs, scored against every other operating reactor in the US fleet from its own operating record. Subscribers see the score, the three sub-scores behind it, and each of the seven measured inputs.
- This unit's composite score and fleet rank
- Reliability, Efficiency and Discipline sub-scores
- All seven measured inputs, with fleet percentiles
- Rank against comparable units, not just the fleet
- Three-year, five-year and lifetime windows
- Five-year trend, and every other operating US reactor
Included with every outage subscription and with NukeWorker Gold membership. Trading the outage rather than working it? The same record, cut by power market, is on NukeGryd.
Scram History 9 events since 2011
Automatic and manual reactor scram (emergency shutdown) events reported to the NRC since 2011. Includes event dates, trip type, and average recovery time. Click the title to view the full fleet scram dashboard.
Arkansas Nuclear 1 has recorded 9 reactor scrams, or emergency shutdowns, since 2011 (5 automatic, 4 manual). On average the unit was back to full power about 14.7 days after each trip.
Technical Specs
Reactor design specifications including type (PWR/BWR), containment design, nuclear steam supply system manufacturer, thermal and electrical power ratings, and current operational status.
Reactor Type:
PWR
Containment:
PWR-DRYAMB
NSS Supplier:
B&W LLP
Turbine Supplier:
WESTINGHOUSE ELECTRIC CORPORATION IAEA
Thermal Power:
2568 MWt
Net Capacity:
833 MWe
Gross Capacity:
903 MWe IAEA
Design Capacity:
850 MWe IAEA
Efficiency:
32.4%
Status:
Operating
Lifetime Output:
296.2 TWh through 2025 IAEA
Licensing
NRC licensing history including docket number, license type and number, construction permit date, operating license issuance, commercial operation date, license renewal, and expiration date.
Docket #:
05000313
License #:
DPR-51
License Type:
OL-FP
Const. Permit:
1968-12-06
Construction Start:
1968-10-01 IAEA
Operating Lic:
1974-05-21
First Criticality:
1974-08-06 IAEA
Grid Connection:
1974-08-17 IAEA
Commercial Op:
1974-12-19
License Renewed:
2001-06-20
License Exp:
2034-05-20
Market & Region
EIA market and grid-region classifications: NERC reliability region, U.S. Census region, balancing authority responsible for grid operations, and whether the unit operates as a rate-regulated utility or a competitive merchant generator. Hover any value for the full name.
NERC Region:
SERC
— SERC Reliability Corporation
Census Region:
WSC
— West South Central
Balancing Authority:
MISO
— Midcontinent Independent System Operator (ISO/RTO)
Market Structure:
Regulated
— Rate-regulated utility (cost-of-service pricing)