Frequently Asked Questions
About Duane Arnold Energy Center Operations

Duane Arnold's safety performance | About security | DAEC in the community

How does a nuclear power plant work? Two types of nuclear power plants used in the United States are the pressurized water reactor (PWR) and the boiling water reactor (BWR). Duane Arnold Energy Center is a BWR.

The boiling water reactor operates in essentially the same way as a fossil fuel generating plant. The fuel in a nuclear power plant is uranium, which is a natural ore found in the ground. Unlike coal, gas and oil, we don’t burn uranium in a nuclear power plant. We get the heat needed to create steam from a process known as fission, or the splitting of atoms -- the smallest parts of any element.

In the reactor of a nuclear power plant, uranium atoms are split apart in a controlled chain reaction. This chain reaction gives off heat energy. This heat energy is used to boil water in the core of the reactor and produces steam. When the steam rises to the top of the pressure vessel, water droplets are removed, and the steam is sent to the turbine generator to turn the turbine. This steam powers this turbine and generates electricity.

Where does Duane Arnold get the water used in plant operations? Water used in the reactor and most other plant systems is piped in from the site’s own well water supply. We then purify the water at the plant to reduce mineral deposits that could otherwise reduce equipment efficiency, and we test the water quality routinely in the plant's on-site laboratory. A separate supply of water that cools used steam for re-use comes from the Cedar River through pipes located beneath the plant. This water is monitored to ensure it meets all safety and environmental standards.

Do we really need the power from Duane Arnold? Yes. The Duane Arnold Energy Center provides enough electricity to meet the annual energy needs of about 600,000 residential customers. The Duane Arnold Energy Center is safe and efficient and provides an affordable source of electricity.

Duane Arnold's safety performance

What is Duane Arnold's performance record? The Duane Arnold Energy Center has been safely and reliably providing energy for Eastern Iowa for more than 30 years. The World Association of Nuclear Operators routinely ranks Duane Arnold as a top-performing U.S. nuclear power plant.

How safe are nuclear power plants? Nuclear power plants are very safe. Duane Arnold maintains very high operating standards and also meets or performs better than regulatory requirements. Employee and public health and safety are of highest priority in everything we do. Our plant workers are thoroughly trained and are experts in their fields. To further protect the public, our nuclear units are designed to use automatic safety systems and multiple safety barriers as part of our "safety first" policy.

Who regulates or oversees the operation of Duane Arnold to make sure it's safe?First, our employees are our most expert safety guardians. Each employee understands that nuclear safety is his or her primary responsibility. Our plants are also monitored closely by the Nuclear Regulatory Commission, a federal government agency that oversees all U.S. nuclear power plants. Daily and special inspections -- some unannounced -- are conducted on site at the Duane Arnold Energy Center to make sure we meet federal regulations in place to protect public health, safety and the environment.

What kind of maintenance is done on plant equipment? We have a rigorous maintenance program at Duane Arnold to make sure the plant runs reliably. Our employees are skilled in using preventive maintenance techniques to test and repair or replace equipment on regular schedules. As a result of this ongoing maintenance, our plant can operate safely and reliably now and in the future.

About security

What kind of security is in place to protect the plant? We have a rigorous maintenance program at Duane Arnold to make sure the plant runs reliably. Our employees are skilled in using preventive maintenance techniques to test and repair or replace equipment on regular schedules. As a result of this ongoing maintenance, our plant can operate safely and reliably now and in the future.

Does Duane Arnold communicate with other law enforcement agencies? Plant security personnel coordinate with local law enforcement agencies, which also participate in onsite security exercises. We also keep in close communication with the FBI, Homeland Security and other government agencies relating to security.

How do you test your security program? Each of our nuclear power plants conducts tactical security drills periodically, and the Nuclear Regulatory Commission evaluates these drills. Drills are quite rigorous, and Duane Arnold has successfully completed each drill.

What physical barriers and emergency equipment protect the Duane Arnold nuclear reactor? The Duane Arnold Energy Center is housed in a massive steel-reinforced concrete reactor containment building that is designed to withstand earthquakes, floods and extreme weather conditions, such as hurricanes and tornadoes. Duane Arnold’s containment building is actually a unique dome-within-a-dome design, which is made up of 6 ½ feet of steel-reinforced concrete.

The reactor vessel itself is made of solid steel and is housed within the containment building. Additionally, the uranium fuel pellets inside the reactor are all encased in zircaloy, an extremely tough metal alloy. Redundant safety shutdown systems are also available to respond in the event of an emergency.

The Electric Power Research Institute, an independent, non-profit energy research group, also recently analyzed aircraft impacts on nuclear plant structures that house reactor fuel. The study results determined that the structures would not be breached, the fuel would be protected and there would be no radiation release.

Duane Arnold in the community

What benefits are provided to our local community by the Duane Arnold Energy Center? The plant is not only located in the community it serves, but is an integral part of that community. Our employees are actively involved in United Way, scout organizations, chambers of commerce and other local organizations. We are one of the area's largest employers, while providing a solid base of community support through local purchases, service contracts and tax payments. Our plant also does its part in providing a reliable source of electricity from safe, affordable and clean nuclear power.