Resources and Additional Information

About Nuclear Energy

Clean Energy
The generation of nuclear energy produces no greenhouse gases or air emissions. Together with renewable energy options, nuclear energy is critical to meeting our environmental and energy goals.
In 2006, U.S. nuclear power plants prevented carbon dioxide emissions equal to taking 99% of all passenger cars off America’s roadways.
Efficient and Reliable Energy
Over the past two decades, nuclear plants have achieved increasingly higher capacity factors with the same or greater levels of safety. The average capacity factor for U.S. power plants in operation in 1980 was 56%; in 1990, 66%; and in 2007, 92%.
Affordable Energy
Since 2001, nuclear plants have achieved the lowest production costs between coal, natural gas and oil. Fuel costs account for 31% of the overall production costs of nuclear plants. Fuel costs for coal, natural gas and oil, however, account for more than 75% of the production costs.
Safe Energy
The lost-time accident rate at nuclear plants is among the lowest in the nation at .3% compared to 2.4% for the manufacturing sector.

About Radiation

Radiation is a natural part of our environment.
The average American receives radiation exposure of about 620 millirem (mrem) annually from all sources, according to the National Council on Radiation Protection and Measurements. About 50% of that exposure comes from naturally occurring radiation from the earth, in the air and water, from outer space and in our own bodies.
Nearly 310 mrem each year comes from man-made sources, such as medical and dental X-rays and certain consumer products. For example, a chest X-ray is about 10 mrem and a CAT scan is about 1,000 mrem or more. One round-trip flight from New York City to Los Angeles provides between 2 mrem and 5 mrem.
By comparison, public exposure to radiation from the entire nuclear energy fuel cycle is 0.4 mrem per year. The average nuclear plant worker receives 160 mrem annually.
In numerous health studies over the past 60 years, the risk of health effects from exposure to low levels of radiation is small. Low level radiation exposure is defined as anything below 10,000 mrem.

Callaway Facts and Figures

Callaway Energy Center is 5 miles north of the Missouri River on a plateau 300 feet above the average river level. More than 70 sites in four states were studied before the Callaway site was selected.
Reactor Containment Building
  • 205 feet tall
  • 150 feet in diameter
  • Constructed of reinforced concrete and steel
Cooling Tower
  • 553 feet tall and 430 feet in diameter at the base.
  • Cools approximately 585,000 gallons of water per minute when the facility is operating at full power. About 15,000 gallons per minute are lost from the top through evaporation, and another 5,000 gallons per minute are sent to the Missouri River as “blowdown” to flush suspended solids from the cooling tower basin. This water is replaced with water from the river, which is five miles south of the energy center.
  • The cooling tower basin holds 11 million gallons of water. The water is 12 feet deep under the tower, and 20 feet deep at the intake to the circulating water pumps that pump the water through the energy center.
  • The temperature of the water going into the tower is 125 degrees Fahrenheit. The tower cools it to 95 degrees Fahrenheit.

Callaway Energy Center Frequently Asked Questions

About Nuclear Fuel

It takes all types of fuel to provide dependable electricity. Nuclear energy centers rely on uranium fuel. The nuclear fuel used in the Callaway Energy Center consists of ceramic pellets of uranium dioxide - each one about one-half inch long and as thick as a pencil.
At a fuel manufacturing facility, these pellets are stacked, end-on-end, inside 12-foot-long tubes called fuel rods, made of Zircaloy metal. The fuel rods are then arranged in bundles called fuel assemblies that are 8 1/2 inches square and weigh about 1,140 pounds.
From the fuel manufacturing facility, fuel assemblies are shipped to Callaway by truck, in rugged shipping casks designed to protect them from damage.
Every 18 months the facility shuts down for several weeks for refueling and maintenance. During refueling, nearly one third of the 193 fuel assemblies are replaced with new ones.

Uranium used for nuclear plants is different than that required for bombs. It is physically impossible for a nuclear explosion to occur at a U.S. nuclear power plant.

Also see Managing Used Nuclear Fuel.

Nuclear Terms

Background radiation
Radiation that is constantly present in the environment and is emitted from a variety of natural and artificial sources. The average American receives radiation exposure of about 620 millirem (mrem) annually, according to the National Council on Radiation Protection and Measurements.

Chain reaction

The continuous splitting of uranium atoms. This process is controlled in the reactor.


The metal (a zirconium alloy) surrounding the uranium fuel, acting as a barrier between the fuel and the water in the reactor coolant system.


Radioactive material, where it is not desired.

Control rods

Metal rods placed between the fuel rods to absorb neutrons and control the fission process. When inserted into the reactor core, the reactor quickly shuts down.

Control Room

The center from which the nuclear plant is operated, monitored and controlled. Operators licensed by the U.S. Nuclear Regulatory Commission are on duty at all times.


The central part of a nuclear reactor containing the fuel assemblies.


The removal of radioactive material.

Emergency Core Cooling System

An important back-up safety system for a nuclear power plant. It provides cooling water for the reactor if the primary cooling system is not operating.

Emergency Planning Zone (EPZ)

The area around a nuclear power plant for which plans are developed for public protection in the event of a nuclear accident. The zone covers approximately a 10-mile radius from the facility. View a map of the Callaway Energy Center Emergency Plant Zone.

Federal Emergency Management Agency (FEMA)

An agency of the federal government charged with establishing policy for and coordinating all civil emergency planning and assistance functions for other federal agencies.


The splitting of an atom into two or more new atoms. When a uranium atom splits in the reactor, two new atoms, neutrons and heat are produced.

Fuel rod

A cylindrical rod, 12 feet long, containing uranium fuel pellets.

Ingestion Exposure Pathway EPZ

The area within a 50-mile radius of the Callaway Energy Center in which people may be indirectly exposed to radiation by eating or drinking contaminated food, milk and water, if radioactive material was released in a nuclear emergency.

Millirem (mrem)

Unit used to measure radiation dosage (1/1000 of a REM). REM stands for Roentgen Equivalent Man, a measure of radiation that indicates potential impact on the human body.

Nuclear Regulatory Commission (NRC)

Agency of the federal government responsible for regulating and inspecting nuclear plants.

Plume Exposure Pathway EPZ

The area within a 10-mile radius of the Callaway Energy Center in which people may be directly exposed to radiation if radioactive material was released in a nuclear emergency.

Primary coolant

Water which passes through the reactor vessel, picking up heat from the nuclear fuel.


The property possessed by some elements which enables them to give off energy in the form of particles or waves.


The large steel vessel in a nuclear power plant containing fuel assemblies, primary coolant and other equipment. The fissioning (or splitting) of atoms is controlled within the reactor.

Reception and Care Centers

Centers providing food and shelter to residents of evacuated areas in the event of a nuclear emergency. The centers are operated by the State of Missouri with assistance from the American Red Cross.


Process of reducing environmental radiation to normally acceptable levels following a nuclear emergency.


Temporary return under controlled conditions, into a restricted, contaminated area with the 10-mile EPZ following a nuclear emergency.


See "millirem."


Comprises the various materials within a nuclear power plant, preventing radiation from escaping into the environment. Shielding can be steel, lead, concrete or water.
State Emergency Management Agency (SEMA)

Missouri state government agency responsible for development and implementation of procedures to protect the public during natural or other emergency conditions.


Specific geographical areas within the EPZ, used in providing protective action recommendations to the public.

Used Fuel

High-level radioactive waste from nuclear power plants, also known as spent fuel.

Callaway Contact Information

For media inquires
Call Ameren Missouri's media hotline at 314.554.2182
For general information about Callaway Energy Center:
Ameren Missouri Callaway Energy Center Communications 
To contact the U.S. Nuclear Regulatory Commission (NRC):
Victor Dricks
NRC Regional Public Affairs Office
Arlington, TX
Office of Public Affairs
NRC Headquarters
Washington, D.C.
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