Duane Arnold
DecommissionedNextEra Energy·Palo, IA·BWR·562 MWe
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Current reactor power level from the most recent NRC daily report.
Shut Down
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Days of continuous operation since the last outage ended. Ranked against all operating units.
2,039
Current Run
days
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Longest recorded period of continuous operation between outages.
2,039
Record Run
days
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (617 days for this 24-month cycle unit) with no trips to 0% power.
3
B2B Runs
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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.
86.7%
Capacity Factor
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Total NRC-reported scram events (emergency reactor shutdowns). Ranked fleet-wide — fewer scrams = better rank.
3
Scrams
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Years since commercial operation began.
45.5
Operating Age
years
Excellence Score, Records & Plant Facts
Breaker-to-Breaker Runs 3 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.
Duane Arnold has logged 3 breaker-to-breaker runs, continuous stretches from one refueling to the next with no trip to zero power. Its longest ran 679 days, and its runs average 671 days.
679
Best Run (days)
RFO 24 (2014-11-25) → RFO 25 (2016-10-04)
671
Avg Run (days)
★ Double breaker-to-breaker
RFO 23 → RFO 24 → RFO 25
All Runs
| 2014-11-25 | 2016-10-04 | 679 days | RFO 24 → RFO 25 |
| 2012-12-08 | 2014-10-04 | 665 days | RFO 23 → RFO 24 |
| 2007-04-05 | 2009-02-02 | 669 days | RFO 20 → RFO 21 |
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: Duane Arnold Energy Center.
Duane Arnold Energy Center is a single-unit nuclear plant in Fayette Township, Linn County, Iowa, near Palo, on the west bank of the Cedar River about eight miles northwest of Cedar Rapids.
Read more
The construction permit was granted on June 17, 1970. The plant has a General Electric BWR-4 boiling water reactor with Mark I containment. Iowa Electric Light and Power, with Central Iowa Power Cooperative and Corn Belt Power Cooperative, applied for the license, and Bechtel was the architect-engineer. The reactor first went critical on March 23, 1974, was connected to the grid on May 19, 1974, and entered commercial operation on February 1, 1975. The August 2020 derecho damaged and leveled its cooling towers, and the reactor was permanently shut down on October 12, 2020.
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.
Duane Arnold has operated for about 45.5 years and averaged a 86.7% lifetime capacity factor, generating roughly 94.8 TWh of electricity. Its longest unbroken run reached 2,039 days.
Lifecycle & Tenure
Operating Age: 45.5 Yrs
Build Time: 4.6 Yrs
Lic. Remaining: N/A Yrs
Production & Power
Lifetime CF: 86.7%
Efficiency: 33.9%
Generated: 94.8 TWh
Reliability & Outages
Record Run: 2,039 Days
Refuelings: 12
Avg Startup: 17 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
| Date | Change | From | To |
|---|---|---|---|
| Aug 7, 2000 | Operator change | Alliant Energy (IES Utilities) (owner, operated it) | Nuclear Management Co (operator only) |
| Jan 27, 2006 | Sold | Alliant Energy (Interstate Power and Light) | NextEra (FPL Energy) |
NEE
NextEra Energy, Inc.
NYSE
$78.51
▼ -0.35 (-0.44%)
Previous Close
78.86
Day's Range
77.93 – 79.85
52-Week Range
74.41 – 98.75
Volume
11,002,251
Delayed quote as of Oct 21, 2026 3:49 PM ET.
Source: Yahoo Finance.
Full quote on Yahoo Finance
NextEra Energy and Dominion Energy (D) announced a merger on 2026-05-18, subject to regulatory and shareholder approval.
Scram History 3 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.
Duane Arnold has recorded 3 reactor scrams, or emergency shutdowns, since 2011 (2 automatic, 1 manual). On average the unit was back to full power about 6 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:
BWR
Containment:
BWR-MARK 1
NSS Supplier:
GE 4
Turbine Supplier:
GENERAL ELECTRIC CO. IAEA
Thermal Power:
1658 MWt
Net Capacity:
562 MWe
Gross Capacity:
624 MWe IAEA
Design Capacity:
538 MWe IAEA
Efficiency:
33.9%
Status:
Decommissioned
Lifetime Output:
172.7 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 #:
05000331
License #:
DPR-49
License Type:
OL-FP
Const. Permit:
1970-06-22
Construction Start:
1970-06-22 IAEA
Operating Lic:
1974-02-22
First Criticality:
1974-03-23 IAEA
Grid Connection:
1974-05-19 IAEA
Commercial Op:
1975-02-01
License Renewed:
2010-12-16
License Exp:
2014-02-21
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.
Balancing Authority:
MISO
— Midcontinent Independent System Operator (ISO/RTO)