GLOSSARY

AEC
Atomic Energy Commission

ALPHA PARTICLE/ALPHA RADIATION
Alpha particles are positively charged particles made up of two protons and two neutrons. The particles lose their energy quickly and do not penetrate the surface of your skin if you are exposed externally. Alpha particles can enter the body through a cut in the skin, by ingestion, or inhalation. Alpha-emitting radioactive substances are harmful once inside the body. Uranium-238 and plutonium-239 are sources of alpha radiation.

ATOM
The atom is the basic component of all matter. It is the smallest part of an element and has all the chemical properties of that element. Atoms are made up of protons and neutrons (in the nucleus) and electrons.

BACKGROUND RADIATION
Background radiation refers to the amount of radiation to which a person is exposed from natural sources. Natural sources of background radiation include radioactive substances in the soil, cosmic radiation originating in outer space, and naturally occurring radionuclides deposited in the human body. On average, a person in the United States gets a dose to the thyroid of approximately 100 millirad per year from background radiation.

BEIR V
The National Research Council's Committee on Biological Effects of Ionizing Radiations is known as BEIR V. The Committee's report is the Health Effects of Exposure to Low Levels of Ionizing Radiation.

BETA PARTICLES/BETA RADIATION
Beta particles are fast moving electrons which are negatively charged particles. Beta radiation can penetrate a few millimeters in human tissue before losing all of its energy. Beta particles may also interact with living tissue by entering from inside the body through breathing contaminated foods. Iodine-131, phosphorus-32, and strontium-90 are all sources of beta radiation.

CANCER
Cancer refers to a malignant growth, capable of invading surrounding tissue or spreading to other parts of the body.

CANNING
The process of sealing the fuel core in either aluminum or zirconium cladding to create a fuel element which was later irradiated in a reactor.

CARCINOGEN
This is an agent that may cause cancer. Ionizing radiations are physical carcinogens; there are also chemical and biologic carcinogens. Biologic carcinogens may be external (such as a virus) or internal (such as genetic defects).

CRIB
Underground chambers open to the ground used to dispose of large volumes of low-level radioactive liquid waste. The liquid waste would percolate in to the underlying soil.

CRITICAL
The condition in which a material undergoes nuclear fission at a self-sustaining rate.

CURIE (Ci)
A curie is a measure of radioactive material. It measures the number of atoms that decay each second. One curie is 37 billion atoms undergoing decay each second. A "nanocurie" is one billionth of a curie. A "picocurie" is one trillionth of a curie.

DECAY (RADIOACTIVE)
Radioactive decay is the process by which the atoms in radioactive substances release energy. Radioactive decay produces a new substance (stable) xenon-131.

DECOMMISSIONING
Retirement of nuclear facilities involving decontamination procedures and dismantlement.

DELAYED HEALTH EFFECT
A health effect of radiation exposure which does not become apparent for months, years or several decades or more after the exposure occurs.

DOE
Department of Energy

DOSE
Dose is the quantity of radiation or energy absorbed by the body. It is measured in rad, millirad, Gray or milliGray.

DOSE ESTIMATE
A calculation of the approximate amount of radiation absorbed by all or part of a person's body. When dose cannot be measured precisely (such as when the exposure happened in the past), a dose estimate is used.

DOSE RECONSTRUCTION
A scientific study that estimates doses to people from releases of radioactivity or other pollutants. The reconstruction is done by determining how much pollution was released, how people came in contact with it and the amount absorbed by all or part of their bodies.

DOWNWINDER
Downwinder is a commonly used term which refers to people living in the pathway of radioactive emissions from a nuclear plant or from atomic bomb test sites.

DuPONT
E.I. DuPont de Nemours and Co.

EPIDEMIOLOGY
The branch of medical science that deals with the frequency and distribution of disease in human populations is known as epidemiology.

EXTERNAL RADIATION
Radiation exposure from a source outside the body. The term refers to radiation, such as gamma rays and X-rays, that can penetrate human skin and thus cause biological damage from outside the body. Compare to internal exposure.

FALLOUT
Fallout is the descent of airborne particles of dust, debris, and radioactive substances. About 200 different substances are formed from a nuclear bomb explosion. Millions of curies of radioactivity in the form of dust and debris get carried into the upper atmosphere by the mushroom cloud. Jet stream winds can carry fallout from bomb blasts around the world within a few months.

FAT MAN
The second atomic bomb created with Hanford plutonium which was dropped on Nagasaki, Japan on August 9th, 1945 killing 40,000 people and injuring 60,000 more. The death eventually reached 140,000.

FISSION
Nuclear fission is the splitting of an atom which releases energy.

FUSION
Nuclear fusion is the process by which two or more atomic nuclei join together, or "fuse", to form a single heavier nucleus.

FUEL (NUCLEAR)
Fissionable material used as the source of power when placed in a critical arrangement in a nuclear reactor.

FUEL SEPARATION
The processing of irradiated (spent) nuclear reactor fuel to recover useful materials such as plutonium, uranium and fission products.

GAMMA RADIATION
A high-energy electromagnetic, ionizing radiation that comes from the nucleus of an atom undergoing radioactive decay. Gamma rays are similar to medical X-rays but are emitted at very specific energies characteristic of their decaying atoms. Gamma rays penetrate body tissues and may damage cells. People exposed to the atomic bombings of Hiroshima and Nagasaki were exposed to gamma radiation. Cesium-137 is a source of gamma radiation.

GEIGER COUNTER
An instrument used to detect and measure the intensity of ionizing radiation

GE
General Electric.

GREEN RUN
A secret experiment at Hanford of between 7,000 and 12,000 curies of iodine-131 to the air on December 2-3, 1949. This experiment was called the Green Run because it involved a processing run of nuclear fuel that had cooled for only a short time (16 days) and was, therefore, green. This shorter cooling time meant that the iodine-131 had less time to decay to lower levels. The Green Run experiment is documented as an intentional release of radiation into the environment.

HALF-LIFE
A half-life is the amount of time it takes for a radioactive substance to decay by releasing radioactive particles or waves, and to lose one-half of its radioactivity. Half-lives for different substances vary from millionths of a second to billions of years. Iodine-131 has a half-life of eight days. At the end of eight days, half of the Iodine-131 becomes stable xenon-131. After another eight days, half of the remaining Iodine 131 will decay into stable xenon-131, and so on. When an atom decays and becomes stable, it is no longer radioactive.

HANFORD REACH
A fifty-two-mile free-flowing stretch of the Columbia River that runs through the Hanford National Monument. Begins from the Priest Rapids Dam to the head of the McNary pool near Richland.

HEDR
Hanford Environmental Dose Reconstruction Project

HEDR STUDY AREA
A 75,000 square-mile area that the HEDR Project used to study exposure from Hanford's radioactive air. The area extends from central Oregon to northern Washington, and from the crest of the Cascade eastern edge of northern Idaho.

HEW
Hanford Engineer Works

HTDS
Hanford Thyroid Disease Study

HYPERTHYRODISM
Hyperthyroidism is a condition caused by an over-active thyroid gland which secretes greater-than-normal amounts of thyroid hormones. Symptoms include nervousness, constant hunger, weight loss and tremors. Scientists do not believe hyperthyroidism is caused by radiation exposure.

HYPOTHYROIDISM
Hypothyroidism is a condition caused by too little thyroid hormone in the body. Symptoms include fatigue, weight gain, intolerance to cold, decreased appetite, constipation, hoarseness, menstrual irregularities, dry skin and hair changes.

INTERNAL RADIATION
Internal radiation exposure occurs when a radioactive substance is taken into the body by eating, drinking or breathing. Compare to external exposure.

IODINE
Iodine is a chemical element in our diet with which thyroid hormone is made.

IODINE 131
One of several radioactive forms of iodine. Iodine-131 gives off beta radiation. It has a half-life of about eight days. Hanford released large amounts of iodine 131 in the process of producing plutonium for nuclear weapons. The HEDR Project concluded that iodine 131 accounted for more than 98 percent of the dose that most people received from Hanford's radioactive releases to the air. The most likely health problems from exposure to iodine-131 are thyroid diseases, particularly benign thyroid tumors (or nodules). It is important to know that there are also beneficial medical uses of iodine-131, with an excellent safety record. These include using iodine-131 for diagnosis, and to treat hyperthyroidism and thyroid cancer

ION EXCHANGE
A process for selectively removing a constituent from a waste stream by reversibly transferring ions between an insoluble solid and the waste stream.

IONIZING RADIATION
Radiation with enough energy to remove one or more electrons from atoms it encounters, creating ions inside living cells. (An ion is an atom that carries a positive or negative electrical charge.) Ionizing radiation leaves positively charged particles such as alpha and beta, and non-particulate forms such as X-rays and gamma radiation. These ions can damage key substances in cells, including the DNA. Such damage can lead to cancer or other defects.

IRRADIATION
Exposure to radiation by being placed near a radioactive source such as inside a nuclear reactor.

ISOTOPES
Isotopes are different forms of the same chemical element, which have different numbers of neutrons but the same number of protons in the nucleus of their atoms. A single element may have many isotopes. For example, stable iodine is iodine-127. Its radioactive isotopes include iodine-129 and iodine-131.

LITTLE BOY
The first atomic bomb made with uranium which was dropped on Hiroshima, Japan on August 6th, 1945 eventually killing 200,000 people.

LOS ALAMOS
Place in northern New Mexico where government scientists have designed and developed nuclear weapons since 1943.

MED
Manhattan Engineer District

THE MANHATTAN PROJECT
This is the name of the United States Government scientific/military project, begun in 1942, that developed the world's first uranium reactor and the first atomic bomb. Hanford was part of the Manhattan Project, producing plutonium used in the atomic bomb dropped on Nagasaki, Japan. The Project ended in 1947.

NCI
National Cancer Institute

PILE
An early term for production reactors.

PLUME
A volume of air, soil or water containing contaminants released from a contaminant source.

PLUTONIUM
A silvery-white radioactive metal that exists as a solid under normal conditions. It is produced when uranium absorbs a neutron. Small amounts of plutonium occur in nature, but large amounts have been artificially produced in nuclear reactors. Hanford produced plutonium-239 for use in nuclear weapons which has a half-life of 24,100 years.

RAD
A rad is a measure of the amount of energy absorbed by the body.

RADIATION
Energy in the form of particles or waves given off by certain atoms. Familiar forms of radiation are heat, light, radio waves and microwaves. Ionizing radiation is a very high-energy form of radiation. It is invisible and cannot be sensed without the use of special equipment. Ionizing radiation can cause cell damage.

RADIOACTIVE
Something is radioactive when it gives off particles or rays from an atom's nucleus.

RADIOISOTOPE
The radioactive form of an element that has all the chemical properties of the stable form of the element is a radioisotope. The radioisotope undergoes radioactive decay.

RADIONUCLIDE or RADIOACTIVE ISOTOPE
An unstable form of an element that can decay and give off radiation. Each radionuclide has a distinct atomic weight number. For example, iodine 131 and iodine 129 are different radionuclides of iodine.

REDOX
A facility and process for separating plutonium and uranium from irradiated reactor fuels by using successive steps of chemical "Reduction Oxidation" with solvent extraction.

RELEASE
Discharge of a substance into the environment.

REM
A rem reflects the radiation dose received by the body, after accounting for the potential for harm from different types of radiation. To convert rads to rems, the number of rads is multiplied by a number that reflects the potential for damage caused by a type of radiation. For beta, gamma and X-ray radiation, this number is generally one. For some neutrons, protons, or alpha particles, the number is twenty. A millirem (mrem) is one-thousandth (1/1,000) of a rem.

PLUTONIUM
A silvery-white radioactive metal that exists as a solid under normal conditions. It is produced when uranium absorbs a neutron. Small amounts of plutonium occur in nature, but large amounts have been artificially produced in nuclear reactors. Hanford produced plutonium for use in nuclear weapons. Most forms of plutonium have very long half-lives. For example, plutonium 239 (which Hanford produced) has a half-life of 24,100 years. Plutonium can cause cancer.

PRODUCTION REACTOR
A nuclear reactor designed for transforming one nuclide into another-usually, a conversion of natural uranium into plutonium.

PUREX
The facility and process using solvent extraction and ion exchange for the separation of plutonium and uranium from irradiated fuel. The Purex Plant was referred to as the "Gray Lady" by plant employees.

SLUG
A fuel element for one of the Hanford fuel reactors.

STABLE
A substance that is not radioactive.

TANK FARMS
A installation of tanks for high-level nuclear liquid waste products.

TARGET
A material placed in a nuclear reactor to be bombarded with neutrons to produce radioactive materials; uranium-238 is used to produce plutonium.

THYROID
The thyroid is a two-lobed gland lying at the base of the throat that produces hormones essential for a variety of metabolic processes in the body. The thyroid secretes hormones that control body growth and metabolism. When iodine is ingested, much of it goes to the thyroid gland.

THYROID DOSE
The amount (or an estimate of the amount) of radiation, or energy, absorbed by the thyroid gland.

TRI-CITIES
The area of Richland, Kennewick and Pasco.

TRINITY TEST
The first ever atomic bomb test held on July 16, 1945. This atmospheric test was executed at the Alamogordo Bombing Range in New Mexico (now known as White Sands Missile Range).

WHOLE BODY DOSE or WHOLE BODY RADIATION
Radiation exposure to gamma rays from outside the body can give a radiation dose to the entire body. Each organ receives approximately the same dose.

URANIUM
A naturally occurring silvery-white slightly radioactive metallic chemical that occurs in uranite and pitchbleblende that can be refined into a heavy metal more dense than lead.

WASTE (HIGH-LEVEL)
Highly radioactive waste resulting from the reprocessing of spent nuclear fuel, including liquid waste produced directly in reprocessing and any solid material derived form such liquid waste that contains fission products in sufficient concentrations. The term indicates the source of the waste not the level of radioactivity; low-waste can be more radioactive than high-level waste.

WASTE (LOW-LEVEL)
Any radioactive material that is not spent fuel, high-level, transuranic waste or the tailings produced by the extraction or concentration of uranium or thorium from any ore processed primarily for its source material.

X-RAYS
A form of radiation produced outside the nucleus of the atom. X-rays can penetrate human skin and pass through the body at the speed of light. As X-rays pass through the body, they may damage cells. The properties of X-rays are identical to gamma rays. Medical X-rays are artificial or machine-made gamma rays.

Glossary (with additions) courtesy of Washington State Dept. of Health Hanford Hanford Health Information Network [http://www.doh.wa.gov/hanford/glossary.html].