Duane Arnold Energy Center
| Company type | Nuclear power plant |
|---|---|
| Industry | Energy |
| Founded | February 1, 1975 |
| Headquarters | Palo, Iowa , United States |
Area served | Iowa |
Key people | John Ketchum (NextEra CEO, as of 2024) |
| Products | Electricity generation |
| Owner | NextEra Energy Resources (70%), Central Iowa Power Cooperative (20%), Corn Belt Power Cooperative (10%) |
Number of employees | Hundreds (exact number not specified) |
| Parent | NextEra Energy Resources (majority owner) |
The Duane Arnold Energy Center (DAEC) was the sole nuclear facility in Iowa, located on a 500-acre plot adjacent to the western shore of the Cedar River, roughly 2 miles north-northeast of Palo and about 8 miles northwest of Cedar Rapids.
Beginning operations in February 1975, DAEC featured a single boiling water reactor with a capacity of 601 MW, manufactured by General Electric. In 2017, the plant attained an impressive capacity factor of 99.04%, and in 2021, its annual electricity output reached 5,235 GWh. The cooling system utilized two mechanical draft cooling towers that drew water from the Cedar River.
NextEra Energy Resources held the majority ownership at 70%, while Central Iowa Power Cooperative and Corn Belt Power Cooperative owned 20% and 10%, respectively. On August 10, 2020, extensive damage to the cooling towers caused by a Midwest derecho prompted the decision to cease repairs on the plant, which was already planned for decommissioning in October 2020.
Electricity Production
During its last full operational year in 2019, Duane Arnold produced a total of 5,235 GWh of electrical energy.
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual (Total) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2001 | 382,045 | 355,555 | 392,652 | 140,468 | 25,150 | 334,683 | 371,033 | 346,686 | 387,653 | 299,934 | 385,585 | 431,278 | 3,852,722 |
| 2002 | 419,086 | 389,255 | 341,087 | 415,917 | 362,672 | 413,091 | 420,340 | 297,088 | 256,177 | 415,893 | 414,668 | 428,684 | 4,573,958 |
| 2003 | 426,122 | 174,819 | 315,195 | 129,836 | 428,226 | 412,413 | 421,188 | 419,019 | 414,515 | 428,839 | 47,782 | 369,703 | 3,987,657 |
| 2004 | 436,867 | 406,472 | 435,372 | 348,679 | 430,021 | 412,259 | 425,362 | 424,868 | 410,790 | 358,931 | 405,590 | 433,737 | 4,928,948 |
| 2005 | 435,019 | 389,371 | 335,065 | ||||||||||
| 350,046 | 417,219 | 430,679 | 436,209 | 424,708 | 440,751 | 433,268 | 449,736 | 4,538,313 | |||||
| 2006 | 447,826 | 404,283 | 446,131 | 408,722 | 440,321 | 422,145 | 428,371 | 430,874 | 406,505 | 442,826 | 364,834 | 452,604 | 5 ,095 ,442 |
| 2007 | 447 ,618 | 39 ,080 | 112 ,431 | 389 ,138 | 450 ,516 | 424 ,532 | 446 ,502 | 442 ,377 | 429 ,795 | 445 ,362 | 437 ,740 | 453 ,784 | 4 ,518 ,875 |
| 2008 | 457 ,143 | 427 ,569 | 452 ,124 | 440 ,067 | 450 ,927 | 425 ,093 | 440 ,375 | 430 ,578 | 431 ,845 | 451 ,846 | 438 ,708 | 435 ,927 | 5 ,282 ,202 |
| 2009 | 394 ,244 | 5 ,357 | 360 ,881 | 399 ,821 | 452 ,957 | 433 ,616 | 452 ,271 | 451 ,155 | 430 ,826 | 400 ,789 | 444 ,369 | 452 ,645 | 4 ,678 ,931 |
| 2010 | 448 ,384 | 416 ,381 | 451 ,812 | 365 ,407 | 410 ,842 | 428 ,419 | 444 ,885 | 442 ,437 | 417 ,963 | 323 ,312 | |||
| 304 521 | 4 450 640 | ||||||||||||
2011
459 664 413 726 452 839 442 326 453 393 429 706 443 408 327 685 439 116 454 320 437 920 461 126 |
5 215 229 | ||||||||||||
2012
460 908 423 779 454 876 440 969 446 229 431 359 439 675 429 765 395 535 57 036 29 454 337 410 |
4 346 995 | ||||||||||||
| 2013
455 731 409 782 458 752 441 980 452 246 431 369 447 624 447 147 430 065 449 169 439 814 457 106 |
5 320 785 | ||||||||||||
| 2014
455 018 406 629 454 318 437 773 440 692 427 081 428 435 417 752 389 557 31 449 32 761 231 003 |
4 152 468 | ||||||||||||
| 2015
418 537 414 738 453 805 438 786 434 472 431 512 434 796 444 377 430 791 446 190 439 209 456 233 |
5 243 446 | ||||||||||||
| 2016
451 835 427 035 453 576 437 215 442 094 329 420 433 422 427 221 402 800 20 861 417 958 459 228 |
4 702 665 | ||||||||||||
| 2017
458 665 411 012 456 960 438 264 446 374 430 857 427 637 440 204 428 408 382 121 439 912 453 095 |
5 213 509 | ||||||||||||
| 2018
454 361 410 060 450 580 435 050 437 412 421 904 426 623 411 903 137 946 409 884 442 856 456 820 |
4 895 399 | ||||||||||||
| 2019
448 846 411 424 453 075 376 139 450 708 432 612 441 330 445 597 429 336 451 258 439 593 455 798 |
5 235 716 | ||||||||||||
| 2020
456 363 425 228 452 682 419 860 392 817 289 107 358 850 109 956 0 -- -- -- |
2 904 863 |
History
During the late 1960s, Iowa Electric Light & Power Co. (currently known as Alliant Energy – West), along with Central Iowa Power Cooperative and Corn Belt Power Cooperative, submitted an application for a nuclear facility license to the Atomic Energy Commission (AEC). On June 17, 1970, they received a construction permit, initially estimating costs at $250 million with a projected duration of 40 months.
The facility was named in honor of Duane Arnold, the former chairman and CEO of Iowa Electric Light and Power Company, who was a strong advocate for nuclear power despite ongoing debates surrounding it. Construction concluded with the reactor achieving criticality on March 23, 1974, exceeding the budget by $50 million. Commercial operation commenced on February 1, 1975, with an initial output limited to 1593 MWt (approximately 535 MWe), which was later increased to the full licensed capacity of 1,658 MWt following modifications completed in 1985.
In May 2000, the NRC authorized the transfer of operational management to Nuclear Management Company LLC (NMC), while ownership remained with Alliant Energy and the cooperatives. A power uprate in 2001 raised capacity to 1,912 MWt, achieved through continuous upgrades that maintained safety standards.
On January 27, 2006, FPL Energy (now NextEra Energy Resources) acquired a 70% stake from Alliant Energy–Interstate Power and Light and assumed operational control from NMC.
Amid the 2008 Iowa Flood, DAEC continued functioning while other plants along the Cedar River ceased operations. Emergency preparedness drills conducted at DAEC contributed to improved regional flood response strategies.
In December 2010, the NRC extended DAEC’s operating license by two decades until 2034. Nevertheless, in January 2018 NextEra announced plans to likely retire the plant by 2025 due to Alliant Energy's transition toward wind and natural gas energy sources. By July 2018, closure was expedited to October 2020 following a $110 million buyout agreement between NextEra and Alliant Energy.
Power production at the plant permanently ended on August 10, 2020, after damage caused by the Midwest derecho earlier that month. An NRC investigation highlighted a slight reduction in secondary containment effectiveness during the event, described by experts as a "close call."
As of September 2024, NextEra CEO John Ketchum mentioned that DAEC could potentially be restarted under specific circumstances, noting interest from multiple data center operators.
Plant equipment
DAEC utilizes a single GE BWR-4 reactor contained within a Mark I containment structure. The plant employs twenty-four mechanical draft cooling towers that draw water from the Cedar River for heat dissipation. All contaminated water is treated onsite under a strict "zero release" policy to avoid any discharge into the river. Onsite dry storage facilities for spent nuclear fuel are designed to accommodate all fuel generated throughout the plant’s operational life, including any extensions granted by license renewals.
A solar park with a capacity of 200 MW paired with a battery energy storage system rated at 75 MW / 300 MWh (4-hour duration) is planned for completion by 2024. While Lazard estimates wholesale electricity replacement costs at $0.04/kWh, incorporating NextEra’s reported cost of capital at 11.4% indicates a more realistic wholesale price closer to $0.21/kWh, excluding expenses related to operations and decommissioning.
Identified Issues
The original Mark I containment was insufficiently sized; Harold Denton of the NRC assessed a 90% likelihood of explosive failure if the containment pressure reached critical levels. This inherent design weakness played a role in the explosions and fires during the 2011 Fukushima Daiichi incident.
Incident Evaluation
In 2010, the Nuclear Regulatory Commission assessed the annual probability of earthquake-induced core damage at Duane Arnold as 1 in 31,250.
After the Fukushima event in 2013, the NRC required Duane Arnold to equip its facility with robust hardened venting systems capable of functioning during severe accidents, including scenarios involving molten core breaches, due to its design parallels with Fukushima reactors.
Impact on Local Community
DAEC provided employment for hundreds within the Cedar Rapids region, with some personnel represented by the International Brotherhood of Electrical Workers and others affiliated with Security, Police and Fire Professionals of America.
The plant operates emergency alert towers designed for tornadoes and nuclear incidents and coordinates emergency preparedness efforts with local, county, and state authorities. These drills are conducted regularly to comply with standards set by the Nuclear Regulatory Commission (NRC) and Federal Emergency Management Agency (FEMA).
DAEC’s tax payments contribute roughly 1% of total revenue for Linn County, Iowa. The 410-acre Pleasant Creek Reservoir, developed jointly by Alliant Energy and the Iowa Conservation Commission, serves dual purposes as a recreational site and a cooling water source during periods of low flow in the Cedar River.
Although DAEC occupies a 500-acre site, only a portion is dedicated to power generation; the remainder is leased for farming or maintained as natural habitat.
A 2014 study from the Nuclear Energy Institute emphasized DAEC’s economic and environmental contributions:
- Nearly 600 full-time employees receive wages exceeding twice the average salary in Benton County, Iowa and approximately 55% higher than those in Linn County, Iowa
- DAEC drives $246 million in local economic activity and adds about $255 million annually to Iowa’s economy
- Each dollar spent by DAEC generates $1.27 within Iowa’s economy
- Supports over 1,100 direct and indirect jobs
- Operations prevent nearly 4 million tons of carbon dioxide emissions annually—the equivalent of removing close to 800,000 vehicles from circulation
Nearby Population
The Nuclear Regulatory Commission defines two emergency planning zones surrounding nuclear facilities: a 10-mile plume exposure pathway zone addressing airborne radioactive contamination risk, and a 50-mile ingestion pathway zone concerning contaminated food and water consumption.
As of 2010, approximately 107,880 people lived within 10 miles of Duane Arnold—a population increase of 8.2% over ten years. Within a 50-mile radius, the population reached 658,634, marking a 7.1% rise since 2000. The city of Cedar Rapids, Iowa lies about 10 miles from the plant's center.
Planned Restart
In early 2025, NextEra Energy Duane Arnold, LLC (NextEra), which holds DAEC’s license, announced intentions to reactivate the plant and resume commercial electricity production.
To proceed with restarting DAEC, NextEra must secure approval from the Nuclear Regulatory Commission (NRC) to reestablish the plant’s licensing framework, restore equipment to safe operational status, and implement any necessary enhancements.
NRC personnel will conduct thorough reviews of regulatory submissions, inspect refurbished components, and maintain oversight to verify compliance with safety and operational requirements. The NRC will also engage in pre-application consultations with DAEC staff and hold public forums concerning the proposed restart.