Administration Building – contains security and administration offices.

Auxiliary Building – houses equipment and laboratories for normal operation of the plant in addition to certain backup systems. The control room is in this building.

Condenser – a large cooling system that changes steam that has spun the turbine back into water to be used again.

Containment Building (or reactor building) – a steel and reinforced concrete structure. It houses the reactor, pressurizer, reactor coolant pumps, steam generators, piping, and other equipment.

Contamination – the presence of radioactive material in unwanted places (on the skin, in water or on food). It usually can be removed by washing.

Cooling Tower – the tall hyperbolic reinforced concrete structure which is used to reject the waste heat from a plant to the atmosphere.

Emergency Planning Zone (EPZ) – a circle around a nuclear power plant, having a 10-mile radius with the plant site at the center. Most of the emergency planning concerning an incident at ANO is concentrated inside this zone.

Emergency Warning System – a network of outdoor sirens and tone alert receivers used to tell the public that emergency information is about to be broadcast over local radio stations.

Entergy Arkansas, LLC – a wholly owned subsidiary of Entergy Corporation, is the owner of Arkansas Nuclear One.

Entergy Corporation – a publicly held holding company that is the sole owner of Entergy Arkansas, Entergy Louisiana, Entergy Mississippi, and Entergy Operations, Inc.

Entergy Louisiana, LLC – a wholly owned subsidiary of Entergy Corporation, is the owner of River Bend Station and Waterford 3 Steam Electric Station.

Entergy Mississippi, LLC – a wholly owned subsidiary of Entergy Corporation, is the owner of Grand Gulf Nuclear Station.

Exposure – receiving radiation. Being in contact with or close to radioactive material will result in exposure.

Fission – the splitting of an atom into two new atoms. When a uranium atom splits, two new atoms, neutrons and heat are produced.

Half-life – the time required for a radioactive substance to lose one-half its radioactivity. Half-life can vary from minutes to years, depending on the source.

Millirem – the unit used to measure radiation dosage. It is 1/1000th of a REM. REM stands for Roentgen Equivalent Man, a measure of radiation that indicates potential impact on human cells.

Moderator – the material used to improve the efficiency of the fission process.

NOAA – the National Oceanic and Atmospheric Administration.

Nuclear fuel – a slightly enriched uranium.

Nuclear Regulatory Commission (NRC) – the federal governmental agency that is responsible for the regulation and inspection of nuclear power plants to assure safety.

Potassium iodide – commonly referred to as KI, is a U.S. Food and Drug Administration (FDA) approved drug that is available without a prescription. KI can be used to protect the thyroid gland from radioactive iodine which may be released under certain emergency conditions at a nuclear power plant. State officials will advise whether KI should be taken in the event of a radiation emergency. People allergic to iodine should not use KI. You may contact your physician to find out if you are allergic to iodine.

Pressurizer – the tank of steam and water that controls the pressure in the reactor system.

Primary coolant – water that is used to transfer the heat from the nuclear fuel to the secondary coolant.

Radioactivity – the property possessed by some elements that give off energy in the form of waves or particles. Radiation may be alpha, beta or gamma.

• Alpha particles are the least penetrating. They can be stopped by a sheet of paper.
• Beta particles can be stopped by thick cardboard.
• Gamma rays are the most penetrating. They are almost the same as X-rays. They can be stopped by heavy shielding such as lead or concrete.

Reactor – a large steel vessel that contains the uranium fuel, primary coolant, control rods, and structures that support the uranium fuel.

Reactor Coolant Pumps – used to circulate the primary coolant water.

Reception Center – is a facility, located well beyond any danger, at which evacuated people will be registered, checked for contamination and sent to a shelter (if needed).

Secondary coolant – the non-radioactive water that is heated into steam which turns the turbine.

Shielding – the material within the nuclear plant that prevents the escape of radiation. Shielding can be steel, lead, concrete, or water.

Steam generator – the piece of equipment that permits heat to be transferred from the primary coolant water to the secondary coolant without the water in the two systems actually mixing.

Steam generator tube – separates reactor coolant water from the water used to make steam. Thousands of tubes are housed in a steam generator.

Turbine – a series of curved blades attached to a shaft and rotated by steam. The turbine is connected to the generator which produces electricity.

Turbine building – contains the secondary (non-radioactive) system of water. Housed in this building are the steam turbines, the electric generator, and the condenser system.