2011 Nuclear Power Plant Sourcebook: Plutonium Radioisotope, Radiation Health Effects and Toxicological Profile, Medical Impact, Fukushima Accident Radioactive Release
U.S. Government, Nuclear Regulatory Commission (NRC), Environmental Protection Agency (EPA), Centers for Disease Control (CDC), Agency for Toxic Substances and Disease Registry (ATSDR)
Smashwords Edition
Copyright 2011 Progressive Management
Questions? Suggestions? Comments? Concerns? Please contact the publisher directly at
ebookhelp@post.com
Remember, the book retailer can't answer your questions, but we can!
* * * * * * * * * * *
Smashwords Edition, License Notes
This ebook is licensed for your personal enjoyment only. This ebook may not be re-sold or given away to other people. If you would like to share this book with another person, please purchase an additional copy for each person you share it with. If you're reading this book and did not purchase it, or it was not purchased for your use only, then you should return to Smashwords.com and purchase your own copy. Thank you for respecting the hard work of this author.
* * * * * * * * * * *
This is a privately authored news service and educational publication of Progressive Management. Our publications synthesize official government information with original material - they are not produced by the federal government. They are designed to provide a convenient user-friendly reference work to uniformly present authoritative knowledge that can be rapidly read, reviewed, or searched. Vast archives of important data that might otherwise remain inaccessible are available for instant review no matter where you are. This e-book format makes a great reference work and educational tool. There is no other reference book that is as convenient, comprehensive, thoroughly researched, and portable - everything you need to know, from renowned experts you trust. For over a quarter of a century, our news, educational, technical, scientific, and medical publications have made unique and valuable references accessible to all people. Our e-books put knowledge at your fingertips, and an expert in your pocket!
Plutonium
CAS ID #: 7440-07-5
Affected Organ Systems: Hepatic (Liver), Musculoskeletal (Muscles and Skeleton), Respiratory (From the Nose to the Lungs)
Cancer Effects: None
Chemical Classification: Radionuclides (radioactive materials)
Summary: Plutonium is a silvery white metal that exists as a solid under normal conditions. It is produced when uranium absorbs an atomic particle. Trace amounts of plutonium occur naturally, but large amounts have been produced in nuclear reactors. Trace levels of plutonium can be found in the environment, from past nuclear bomb tests, in several forms called isotopes. The most common plutonium isotopes are plutonium-238 and plutonium-239. Plutonium undergoes radioactive decay. In this decay process, energy is released and a new product is formed. The energy released is called radiation. When plutonium decays, it divides into two parts-a small part that is called "alpha" radiation and a large part called a daughter. The daughter is also radioactive, and it, too, continues to decay until a nonradioactive daughter is formed. During these decay processes, three types of radiation are released-alpha, beta, and gamma. Alpha particles can travel only a short distance and cannot travel through your skin. Beta particles can penetrate through your skin, but they cannot go all the way through your body. Gamma radiation can go all the way through your body.
* * * * * * * * * * * *
Highlights
Plutonium is a radioactive material that is produced in nuclear reactors; only trace amounts occur naturally. It has been found to cause lung, liver, and bone cancer in plutonium workers. Plutonium has been found in at least 16 of 1,699 National Priorities List sites identified by the Environmental Protection Agency (EPA).
What is plutonium?
Plutonium is a silvery-white radioactive metal. Most plutonium is found combined with other substances. Trace amounts of plutonium occur naturally, but large amounts have been produced in nuclear reactors. Trace levels of plutonium can be found in the environment, from past nuclear bomb tests. The most common plutonium isotopes are plutonium-238 and plutonium-239.
Plutonium can exist in several forms, called isotopes, based on how it was made. All plutonium isotopes are radioactive. Their atoms eventually change into a different element and give off radiation. This process is called radioactive decay. The most common plutonium isotopes are plutonium-238 and plutonium-239.
The half-life is the time it takes for half of the plutonium to undergo radioactive decay and change forms. The half-life of plutonium-238 is 87.7 years. The half-life of plutonium-239 is 24,100 years.
Plutonium-239 is used to manufacture nuclear weapons. Plutonium-238 is used as a heat source in nuclear batteries to produce electricity in devices such as unmanned spacecraft and interplanetary probes.
What happens to plutonium when it enters the environment?
Plutonium released during atmospheric testing of nuclear bombs, which ended in 1980, is the source of most of the plutonium in the environment worldwide.
Plutonium is also released to the environment from research facilities, waste disposal, nuclear fuel reprocessing facilities, nuclear weapons production facilities, and accidents at facilities where plutonium is used.
Plutonium can be transported in the atmosphere.
It can be deposited on land or water by settling or by precipitation.
Plutonium can stick to particles in soil, sediment, and water.
Plutonium will undergo radioactive decay in the environment. .
How might I be exposed to plutonium?
Everyone is exposed to very low levels of plutonium in air, and possibly in drinking water and food.
Exposure to higher levels could occur from an accidental release during its use.
Exposure during transport and disposal is unlikely because transport containers are virtually indestructible by accident or fire; disposal sites are deep underground and away from the public.
Workers at nuclear facilities using plutonium may be exposed to higher levels of it.
People who live near facilities that use plutonium in their operations may be exposed to it from accidental releases to the air.
How can plutonium affect my health?
The main health effect from exposure to plutonium is cancer which may occur years after exposure. The types of cancers you would most likely develop are cancers of the lung, bones, and liver. These types of cancers have occurred in workers who were exposed to plutonium in air at much higher levels than is in the air that most people breathe.
How likely is plutonium to cause cancer?
The Department of Health and Human Services (DHHS), International Agency for Research on Cancer (IARC), and the EPA’s Office of Air and Radiation consider plutonium to be a human carcinogen. The likelihood of you developing cancer depends on how much plutonium you were exposed to and how long it remains in your body. The levels which most people are exposed are very low and of little health consequence.
How can plutonium affect children?
Studies in young animals have shown that a larger amount of the plutonium deposited in the lung will move to growing bones. Therefore, it is possible that the bones of children could be more severely affected by plutonium than the bones of adults; however, this has not been shown in humans or tested in laboratory animals.
Studies in animals have also shown that a larger amount of plutonium that enters the gut of newborn animals is absorbed into the body.
We do not know if plutonium causes birth defects.
How can families reduce the risks of exposure to plutonium?
People do not generally live near facilities that use plutonium in their operations. Some people may be slightly more exposed to plutonium due to releases of plutonium through filtered stack-emissions or waste water. Any releases are to be within regulatory limits. Disposal sites are deep underground and away from the public.
If you know or suspect that plutonium has been released to the air, you should leave the area immediately.
Is there a medical test to show whether I've been exposed to plutonium?
Plutonium can be measured in the urine and feces even at very low levels. These measurements can be used to estimate the total amount of plutonium that has entered the body.
Has the federal government made recommendations to protect human health?
The U.S. Nuclear Regulatory Commission (USNRC) has established an exposure limit of 0.1 rem/year for the general public.
USNRC also requires a limit of 5 rem/year for workers in industries where exposure to radiation may occur and 0.5 rem for the pregnancy period following the declaration of pregnancy by a woman in an industry where exposure to radiation may occur. These regulations are for all forms of ionizing radiation combined, so they are not only for plutonium.
References
Agency for Toxic Substances and Disease Registry (ATSDR). 2010. Toxicological Profile for Plutonium. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.
* * * * * * * * * * * *
Public Health Statement for Plutonium
November 2010
CAS# 7440-07-5
This Public Health Statement is the summary chapter from the Toxicological Profile for plutonium. It is one in a series of Public Health Statements about hazardous substances and their health effects. For more information, call the ATSDR Information Center at 1-800-232-4636.
This public health statement tells you about plutonium and the effects of exposure to it.
The Environmental Protection Agency (EPA) identifies the most serious hazardous waste sites in the nation. These sites are then placed on the National Priorities List (NPL) and are targeted for long-term federal clean-up activities. Plutonium has been found in at least 16 of the 1,689 current or former NPL sites. Although the total number of NPL sites evaluated for this substance is not known, strict regulations make it unlikely that the number of sites at which plutonium is found would increase in the future as more sites are evaluated. This information is important because these sites may be sources of exposure and exposure to this substance may harm you.
When a substance is released from a large area, such as an industrial plant, or from a container, such as a drum or bottle, it enters the environment. This release does not always lead to exposure. You are normally exposed to a substance only when you come in contact with it. You may be exposed by breathing, eating, or drinking the substance, or by skin contact. However, since plutonium is radioactive, you can also be exposed to its radiation if you are near it.
External exposure to radiation may occur from natural or man-made sources. Naturally occurring sources of radiation are cosmic radiation from space or radioactive materials in soil or building materials. Manmade sources of radioactive materials are found in consumer products, industrial equipment, atom bomb fallout, and to a smaller extent from hospital waste and nuclear reactors.
When you are exposed to plutonium, many factors will determine whether you will be harmed. These factors include the dose (how much), the duration (how long), and how you come in contact with it. You must also consider any other chemicals you are exposed to and your age, sex, diet, family traits, lifestyle, and state of health.
What is plutonium?
Radioactive metal Plutonium is a radioactive element. Pure plutonium is a silvery-white metal.
Most plutonium is found combined with other substances, for example, plutonium dioxide (plutonium with oxygen) or plutonium nitrate (plutonium with nitrogen and oxygen).
Plutonium is usually measured in terms of its radioactivity (curies or becquerels). Both the curie (Ci) and the becquerel (Bq) tell us how much a radioactive material decays every second.
Exists in various forms called isotopes
The most common plutonium isotope is plutonium-239.
Plutonium is not stable Each radioactive isotope of an element constantly gives off radiation, which changes it into an isotope of a different element or a different isotope of the same element. This process is called radioactive decay.
Plutonium-238 and plutonium-239 give off alpha particles (sometimes referred to as alpha radiation) and transform into uranium-234 and uranium 235, respectively.
The half-life is the time it takes for half of the atoms of a radionuclide to undergo radioactive decay and change it into a different isotope. The half-life of plutonium-238 is 87.7 years. The half-life of plutonium-239 is 24,100 years. The half-life of plutonium-240 is 6,560 years.
Produced in nuclear power plants and used in nuclear weapons and batteries Very small amounts of plutonium occur naturally. Plutonium-239 and plutonium-240 are formed in nuclear power plants when uranium-238 captures neutrons. Plutonium is used to produce nuclear weapons.
Plutonium-238 is used as a heat source in nuclear batteries to produce electricity in devices such as unmanned spacecraft and interplanetary probes.
What happens to plutonium when it enters the environment?
Released during testing of nuclear weapons
Plutonium released during atmospheric testing of nuclear weapons, which ended in 1980, is the source of most of the plutonium in the environment worldwide. The plutonium released during these tests was deposited on land and water. The small amount that remains in the atmosphere continues to be deposited as it slowly settles out.
Plutonium is also released to the environment from research facilities, waste disposal, nuclear fuel reprocessing facilities, nuclear weapons production facilities, and accidents at facilities where plutonium is used.
Deposited in water or soil
Plutonium can be transported in the atmosphere usually when it is attached to particles in the air. It can be deposited on land or water by settling or by rain. Plutonium can stick to particles in soil, sediment, and water.
Plutonium isotopes will undergo radioactive decay in the environment.
How might I be exposed to plutonium?
You may be exposed to plutonium by breathing air, drinking water, or eating food containing plutonium; however, the levels of plutonium in air, water, soil, and food are very low.
Soil
Average plutonium levels in surface soil from fallout range from 0.01 to 0.1 picocuries (pCi) per gram of soil (1 picocurie equals one-trillionth [10-12] of a curie).
Air Plutonium concentrations in air are generally low. Baseline plutonium-239 concentrations in air ranging from 1.6x10-6 to 3.8x10-6 pCi per cubic meter of air (pCi/m3) have been reported.
Workplace
Persons who work at nuclear fuel and weapons production facilities have a greater chance of being exposed than individuals in the general population.
Accident
You could be exposed to plutonium if there was an accidental release of plutonium during use. It is very unlikely you would be exposed as the result of a traffic accident or disposal. Plutonium transport containers are virtually indestructible by accident or fire. The disposal site is deep underground and away from the public.
How can plutonium enter and leave my body?
Plutonium can enter your body when it is inhaled or swallowed
When you breathe air that contains plutonium, some of it will get trapped in your lungs. Some of the trapped plutonium will move to other parts of your body, mainly your bones and liver. The amount of plutonium that stays in your lungs depends on the solubility of the plutonium that is in the air you breathe.
A small amount of the plutonium you swallow (much less than 1%) will enter other parts of your body (mainly your bones and liver).
If plutonium gets onto your healthy skin, very little, if any, plutonium will enter your body. More plutonium will enter your body if it gets onto injured skin, such as a cut or burn.
Plutonium in your body will remain there for many years
Plutonium leaves your body very slowly in the urine and feces. If plutonium were to enter your lungs today, much of the plutonium would still be in your body 30–50 years later.
How can plutonium affect my health?
This section looks at studies concerning potential health effects in animal and human studies.
Lung, liver, and bone cancer
You may develop cancer depending on how much plutonium is in your body and for how long it remains in your body. The types of cancers you would most likely develop are cancers of the lung, bones, and liver. These types of cancers have occurred in workers who were exposed to plutonium in air at much higher levels than is in the air that most people breathe.
Affect ability to fight infections
In laboratory animals, plutonium affected the animal’s ability to resist disease (immune system).
How can plutonium affect children?
This section discusses potential health effects in humans from exposures during the period from conception to maturity at 18 years of age.
There are differences between children and adult
Studies in young animals have shown that a larger amount of the plutonium deposited in the lung will move to growing bones. Therefore, it is possible that the bones of children could be more severely affected by plutonium than the bones of adults; however, this has not been shown in humans or tested in laboratory animals.
Studies in animals have also shown that a larger amount of plutonium that enters the gut of newborn animals is absorbed into the body.
Effects in unborn children
We do not know if plutonium causes birth defects or affects the ability to have children, although some plutonium that reaches the blood can be found in ovaries and testes.
A large portion of the plutonium in the body of adults is in bone. It is possible that plutonium in the bones of a pregnant woman may move to the fetus, when the calcium from the mother’s bone is being used to build the bones of the fetus.
How can families reduce the risk of exposure to plutonium?
Exposure of the general population to plutonium will be small. Plutonium levels in water, air, and food are generally low in areas that have not been contaminated by accidents or other releases of radioactive materials.
Risk for working
People working at facilities using plutonium that is not highly contained will be more highly exposed to plutonium than the general population.
Risk near the home
People do not generally live near facilities that use plutonium in their operations. Some people may be slightly more exposed to plutonium due to releases of plutonium through filtered stack-emissions or waste water. Any releases are to be within regulatory limits. Disposal sites are deep underground and away from the public.
Risk in the air you breathe Breathing plutonium-contaminated air is the most dangerous way to be exposed to plutonium. If you know or suspect that plutonium has been released to the air, you should leave the area immediately.
Is there a medical test to determine whether I have been exposed to plutonium?
Can be measured in urine and feces
Plutonium can be measured in the urine and feces even at very low levels. These measurements can be used to estimate the total amount of plutonium that has entered the body.
The levels of plutonium in the body can be used to predict the kind of health effects that might develop from that exposure.
Plutonium inside the body can be detected from outside the body
Some sensitive equipment can measure the weak gamma rays that travel to the outside of the body after they are released from plutonium and other radioactive materials inside the body. In the United States, this equipment is only available in a few locations.
What recommendations has the federal government made to protect human health?
The federal government develops regulations and recommendations to protect public health. Regulations can be enforced by law. Federal agencies that develop regulations for toxic substances include the Environmental Protection Agency (EPA), the Occupational Safety and Health Administration (OSHA), the Food and Drug Administration (FDA), and the U.S. Nuclear Regulatory Commission (USNRC).
Recommendations provide valuable guidelines to protect public health but cannot be enforced by law. Federal organizations that develop recommendations for toxic substances include the Agency for Toxic Substances and Disease Registry (ATSDR), the National Institute for Occupational Safety and Health (NIOSH), and the FDA.
Regulations and recommendations can be expressed as “not-to-exceed” levels, that is, levels of a toxic substance in air, water, soil, or food that do not exceed a critical value that is usually based on levels that affect animals; they are then adjusted to levels that will help protect humans. Sometimes these not-to-exceed levels differ among federal organizations because they used different exposure times (an 8-hour workday, a 24-hour day, or a work-year), different animal studies, or other factors.
Recommendations and regulations are also updated periodically as more information becomes available. For the most current information, check with the federal agency or organization that provides it.
The U.S. Nuclear Regulatory Commission (USNRC) has recommended the following radiation exposure limits for the general public and for workers:
General public
0.1 rem/year for the general public and 0.5 rem/year for people who work with patients in nuclear medicine. These regulations are for all forms of radiation combined, so they are not only for plutonium.
Workers
5 rem/year for workers in industries where exposure to radiation may occur and 0.5 rem for the pregnancy period following the declaration of pregnancy by a woman in an industry where exposure to radiation may occur.
These recommended radiation exposure limits are for all forms of radiation combined and are not specific to plutonium. The limits are expressed in units called rem (roentgen equivalent man). A rem is a radiation unit that expresses the radiation equivalent dose to a particular organ or tissue. The limits on equivalent dose are used to calculate the limits on the amount of radioactive substances that can be inhaled or ingested.
References
Agency for Toxic Substances and Disease Registry (ATSDR). 2010. Toxicological profile for Plutonium. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.
* * * * * * * * * * * *
Plutonium
Plutonium is a radioactive, metallic element with atomic number 94. It was discovered in 1940 at the University of California, Berkeley. It has several unique properties which make it both very useful and potentially dangerous to handle.
Because plutonium occurs in nature in only minute amounts, it must be considered for all practical purposes a man-made element (some pitchblende ores, once a main source of uranium and radium, contain one part per trillion natural plutonium).
Plutonium Isotope Half-Lives
There are 15 isotopes (another form) of plutonium. Some isotopes of plutonium are fissionable meaning that the atomic nucleus is unstable and will split apart, resulting in the release of large amounts of energy. Pu-239 and Pu-241 are the most abundant of the fissionable isotopes of plutonium.
A half-life is the time in which one half of the atoms of a radioactive substance disintegrates into another nuclear form, hence, the time to halve its radioactive strength. Pu-239 has a half-life of 24,000 years and Pu-241's half-life is 14.4 years. The plutonium isotope with the shortest half-life of 20 minutes is Pu-233. Plutonium-244, which occurs naturally, has the longest half-life of 80,000,000 years.
Source of Plutonium
Plutonium is created by the absorption of neutrons by uranium. Plutonium was first made in large quantities in the World War II Manhattan Project for use in atomic bombs. Because it is fissionable, it also can be used, under different circumstances, as fuel for reactors. Present day light water reactors create plutonium as the uranium fissions (splitting of atoms). Some of the neutrons released during the fissioning of uranium interact with yet other uranium atoms to form, plutonium. Some of this plutonium created in the fuel of the reactor core is itself fissioned thereby helping to sustain the chain reaction of splitting atoms. The plutonium which does not fission by the end of the core's life remains in the fuel rod.
Plutonium-238, in addition to its ability to fission, is self-heating and can be potentially valuable in thermoelectric generators for use in space program instruments and heart pacemakers.
Pathways in the Body
The most common form of plutonium is plutonium oxide which is virtually insoluble. The behavior of plutonium oxide in the body varies with the way in which it is taken. If one drinks or eats it, a very large percentage of it will be eliminated from the body quite rapidly in body wastes. If plutonium oxide is inhaled, part of it, usually between 20 and 60 percent depending upon such things as the size of the particles, is retained in the lung. The rest is eliminated from the body within several days. Of that which remains in the lungs, about half will be removed each year, some to be excreted, some to lodge in the lymph nodes, and a very small amount will be deposited in other organs, mainly bone. If plutonium enters the body through an open wound, depending on its form, it may move directly into body organs, mainly bone and liver. The next most common form of plutonium is plutonium nitrate-a chemical that is somewhat more soluble than the oxide. Plutonium nitrate's behavior in the body is similar to plutonium oxide, however, it moves out of the lung more rapidly.
Radiological Considerations
Since plutonium was discovered in 1940, it was not a part of the extensive radiological experience of the pre-World War II decades. By the time it was evident that plutonium would be available in substantial quantities, the scientific community was well aware that highly radioactive material could be hazardous. In some ways, plutonium was less hazardous than some other radioactive materials then in use. Plutonium does not produce strong, penetrating radiation nor is it hard to contain. But it is a long-lived alpha emitting material that, if it gets inside the body, could deposit in the bones or in lungs and possibly increase an individual's cancer risk. Therefore, very low limits were established for exposure to plutonium.
Toxicity
Recent research with one of the least radioactive isotopes of plutonium (plutonium-242, which has a half-life of 376,000 years) indicates that plutonium in the body may contribute to the development of tumors. In general, however, plutonium isotopic mixtures that are commonly encountered in the nuclear fuel cycle, nuclear weapons programs, or thermoelectric generator applications exhibit much higher radiological toxicity than chemical toxicity.
Production and Disposition
Over 1500 metric tons of plutonium have been produced world wide, some for weapons use, and most of the rest as a by-product of electricity production. It is important to note that the plutonium produced as a by-product in a nuclear power reactor is created in its many isotopic forms, including Pu-239, Pu-240, Pu-241, and Pu-242. This is known as "reactor-grade" plutonium. In contrast, "weapons-grade" plutonium contains almost pure (over 90%) Pu-239. Plutonium-239 is created in a reactor that is specially designed and operated to produce Pu-239 from uranium.
With the end of the Cold War, the United States and the former Soviet Union began dismantling thousands of nuclear weapons which has resulted in a surplus of highly enriched uranium and plutonium. To dispose of this surplus and protect against it falling into the wrong hands, the U.S. has plans to mix the plutonium with uranium to make mixed oxide (MOX) fuel for power reactors. The intent of the MOX fuel program is to irradiate the so called "weapons-grade" plutonium, converting it to "reactor-grade", which will make the plutonium no longer suitable for use in advanced nuclear weapons. There would be no reprocessing or subsequent reuse of the MOX spent fuel. The fuel would be disposed of in a waste repository along with other high-level nuclear waste. October 2003
* * * * * * * * * * * *
Plutonium (chemical symbol Pu) is a radioactive metal with Atomic Number 94. Plutonium is considered a man-made element, although scientists have found trace amounts of naturally occurring plutonium produced under highly unusual geologic circumstances. The most common radioisotopes of plutonium are plutonium-238, plutonium-239, and plutonium-240.
Who discovered plutonium?
Plutonium was identified by nuclear chemist Glenn T. Seaborg and his colleagues Joseph W. Kennedy, Edwin M. McMillan, and Arthur C. Wahl, in 1941 at the University of California - Berkeley. However, wartime secrecy prevented them from announcing the discovery until 1948.
Where does plutonium come from?
Plutonium is created from uranium in nuclear reactors. When uranium-238 absorbs a neutron, it becomes uranium-239 which ultimately decays to plutonium-239. Different isotopes of uranium and different combinations of neutron absorptions and radioactive decay, create different isotopes of plutonium.
Some of the plutonium-239 in the fuel rods burns (fissions) along with uranium and helps produce heat, which is converted into electricity. As fission continues, the reaction products remain in the fuel pellets and absorb neutrons, slowing ("poisoning") the fission process. Finally, the ratio of poisons to fissional materials reaches a point at which the fuel is said to be "spent" and must be replaced. However, even spent fuel contains some plutonium.
The majority of plutonium was produced for nuclear weapons in several government reactors designed to maximize the production of plutonium. Between 1944 and 1988, the U.S. built and operated these ‘production reactors' at high-security government facilities. In all, the U.S. produced about 100 metric tons of plutonium.
The reactors made plutonium by bombarding special fuel rods containing uranium with neutrons. Once the maximum amount of plutonium was produced, workers removed the fuel rods (now called ‘spent fuel') from the reactor. The spent fuel rods were extremely radioactive, and the process for recovering the plutonium used only remote-controlled equipment.
First workers used strong acid to dissolve the fuel rods. Then they treated the mixture with chemicals to precipitate the plutonium so that it would settle out. The process was very expensive and at the time made plutonium about the most expensive material on earth. This processing also left behind over 100 million gallons of exceedingly hazardous mixed wastes of acids and radioactive fission products. Part of our legacy of nuclear weapons production is dealing with these high-level wastes.
In extremely rare cases, rocks with a high localized concentration of uranium can provide the right conditions for making small amounts of plutonium naturally. This natural process is called spontaneous fission. Only very small (trace) amounts of natural plutonium have ever been found in nature.
What are the properties of plutonium?
Plutonium is a silvery-grey metal that becomes yellowish when exposed to air. It is solid under normal conditions, and is chemically reactive.
Plutonium has at least 15 different isotopes, all of which are radioactive. The most common ones are Pu-238, Pu-239, and Pu-240. Pu-238 has a half-life of 87.7 years. Plutonium-239 has a half-life of 24,100, and Pu-240 has a half-life 6,560 years. The isotope Pu-238 gives off useable heat, because of its radioactivity.
What is plutonium used for?
Plutonium-239 is used to make nuclear weapons. For example, the bomb dropped on Nagasaki, Japan, in 1945, contained Pu-239. The plutonium in the bomb undergoes fission in an arrangement that assures enormous energy generation and destructive potential.
The isotope, plutonium-238, is not useful for nuclear weapons. However it generates significant heat through its decay process, which make it useful as a long-lived power source. Using a thermocouple, a device that converts heat into electric power, satellites rely on plutonium as a power source. Tiny amounts also provide power to heart pacemakers.
Some foreign countries mix isotopes of plutonium and uranium to manufacture special reactor fuel called mixed-oxide fuel, for commercial nuclear power reactors. The plutonium increases the power output. The U.S. does not currently manufacture mixed-oxide fuel, but is funding research in this type of reactor fuel as a means of dealing with excess plutonium in U.S. stockpiles.
Exposure to Plutonium
How does plutonium get into the environment?
Plutonium was dispersed world wide from atmospheric testing of nuclear weapons conducted during the 1950s and ‘60s. The fallout from these tests left very low concentrations of plutonium in soils around the world.
Nuclear weapons production and testing facilities (Hanford, WA; Savannah River, GA; Rocky Flats, CO; and The Nevada Test Site, in the United States, and Mayak and Semi Plafinsk in the former Soviet Union), also released small amounts. Some releases have occurred in accidents with nuclear weapons, the reentry of satellites that used Pu-238, and from the Chernobyl nuclear reactor accident.
How does plutonium change in the environment?
All isotopes of plutonium undergo radioactive decay. As plutonium decays, it releases radiation and forms other radioactive isotopes. For example, Pu-238 emits an alpha particle and becomes uranium-234; Pu-239 emits an alpha particle and becomes uranium-235.
This process happens slowly since the half-lives of plutonium isotopes tend to be relatively long: Pu-238 has a half-life of 87.7 years; Pu-239 has a half-life is 24,100 years, and Pu-240 has a half-life of 6,560 years. The decay process continues until a stable, non-radioactive element is formed.
How do people come in contact with plutonium?
Residual plutonium from atmospheric nuclear weapons testing is dispersed widely in the environment. As a result, virtually everyone comes into contact with extremely small amounts of plutonium.
People who live near nuclear weapons production or testing sites may have increased exposure to plutonium, primarily through particles in the air, but possibly from water as well. Plants growing in contaminated soil can absorb small amounts of plutonium.
How does plutonium get into the body?
People may inhale plutonium as a contaminant in dust. It can also be ingested with food or water. Most people have extremely low ingestion and inhalation of plutonium. However, people who live near government weapons production or testing facilities may have increased exposure. Plutonium exposure external to the body poses very little health risk.
What does plutonium do once it gets into the body?
The stomach does not absorb plutonium very well, and most plutonium swallowed with food or water passes from the body through the feces. When inhaled, plutonium can remain in the lungs depending upon its particle size and how well the particular chemical form dissolves. The chemical forms that dissolve less easily may lodge in the lungs or move out with phlegm, and either be swallowed or spit out. But, the lungs may absorb chemical forms that dissolve more easily and pass them into the bloodstream.
Once in the bloodstream, plutonium moves throughout the body and into the bones, liver, or other body organs. Plutonium that reaches body organs generally stays in the body for decades and continues to expose the surrounding tissue to radiation.
Health Effects of Plutonium
How can plutonium affect people's health?
External exposure to plutonium poses very little health risk, since plutonium isotopes emit alpha radiation, and almost no beta or gamma radiation. In contrast, internal exposure to plutonium is an extremely serious health hazard. It generally stays in the body for decades, exposing organs and tissues to radiation, and increasing the risk of cancer. Plutonium is also a toxic metal, and may cause damage to the kidneys.
Is there a medical test to determine exposure to plutonium?
There are tests that can reliably measure the amount of plutonium in a urine sample, even at very low levels. Using these measurements, scientists can estimate the total amount of plutonium present in the body. Other tests can measure plutonium in soft tissues (such as body organs) and in feces, bones, and milk. However, these tests are not routinely available in a doctor's office because they require special laboratory equipment.
Protecting People from Plutonium
What can I do to protect myself and my family from plutonium?
Since plutonium levels in the environment are very low, they pose little risk to most people. However, people who live near government weapons production or testing sites may have higher exposure.
Plutonium particles in dust are the greatest concern, because they pose the greatest health risk. People living near government weapons facilities can track radiation monitoring data made available by site personnel. If radiation levels rise, they should follow the radiation protection instructions given by site personnel.
How do I know if I'm near plutonium?
You must have special equipment to detect the presence of plutonium.
What is EPA doing to protect us from plutonium?
EPA sets health-based limits on radiation in air, soil, and water. Federal government agencies are required to meet EPA standards the same as commercial industries. Using its authority under the Safe Drinking Water Act, EPA limits the amount of radiation in community water systems by establishing maximum contaminant levels. Maximum Contaminant Levels limit the amount of activity from alpha emitters, like plutonium, to 15 picocuries per liter.
EPA also protects people against exposure from soil and ground water from sites that have been contaminated with plutonium. We set criteria that soil and ground water from the sites must meet before releasing the sites for public use.
Rather than limiting the concentration of plutonium itself, the criteria limit the cancer risk the sites pose. A person's added risk of developing cancer is limited to no more than about 1-in-10,000 and if possible to 1-in-1,000,000, or less. Under the Clean Air Act, EPA limits the dose to humans from radionuclides to 10 millirem from emissions to air.
Radionuclides in Drinking Water
This site provides information about radionuclides in drinking water and guidance to help states and water systems comply with EPA's limits on radionuclides in drinking water.
RadNESHAPS
This site provides information on EPA's National Emission Standards for Hazardous Air Pollutants: Radionuclides.
EPA sets standards for radioactive waste storage and disposal facilities. We can't treat plutonium or other radioactive materials to get rid of their radioactivity. We can only isolate and store them until they decay. The extremely long half-lives of some plutonium radioisotopes make the management of spent nuclear fuel, and wastes from nuclear weapons facilities a difficult problem.
One of EPA's responsibilities has been to develop public health and safety standards for the two major U.S. nuclear waste storage and disposal facilities. The Waste Isolation Pilot Plant in New Mexico stores transuranic wastes. They range from slightly contaminated clothing to barrels of waste so radioactive that it can only be handled with remote control equipment. The proposed Yucca Mountain repository is designed to store high-level radioactive waste and spent nuclear fuel.
EPA also responds to radiation emergencies. Additionally, EPA helps state and local governments during emergencies that involve radioactive materials. We provide guidance on ways to protect people from harmful exposure to radiation. We can also monitor radiation levels in the environment and assess the threat to public health. We also work with international radiation protection organizations to prepare for large scale foreign emergencies such as Chernobyl. EPA also works with law enforcement agencies to develop counter terrorism plans.
* * * * * * * * * * * *
PUBLIC HEALTH STATEMENT
This public health statement tells you about plutonium and the effects of exposure to it.
The Environmental Protection Agency (EPA) identifies the most serious hazardous waste sites in the nation. These sites are then placed on the National Priorities List (NPL) and are targeted for long-term federal clean-up activities. Plutonium has been found in at least 16 of the 1,689 current or former NPL sites. Although the total number of NPL sites evaluated for this substance is not known, strict regulations make it unlikely that the number of sites at which plutonium is found would increase in the future as more sites are evaluated. This information is important because these sites may be sources of exposure and exposure to this substance may be harmful.
When a substance is released from a large area, such as an industrial plant, or from a container, such as a drum or bottle, it enters the environment. This release does not always lead to exposure. You are normally exposed to a substance only when you come in contact with it. You may be exposed by breathing, eating, or drinking the substance, or by skin contact. However, since plutonium is radioactive, you can also be exposed to its radiation if you are near it.
External exposure to radiation may occur from natural or man-made sources. Naturally occurring sources of radiation are cosmic radiation from space or radioactive materials in soil or building materials. Man-made sources of radioactive materials are found in consumer products, industrial equipment, atom bomb fallout, and to a smaller extent from hospital waste and nuclear reactors.
When you are exposed to plutonium, many factors will determine whether you will be harmed. These factors include the dose (how much), the duration (how long), and how you come in contact with it. You must also consider any other chemicals you are exposed to and your age, sex, diet, family traits, lifestyle, and state of health.
1. PUBLIC HEALTH STATEMENT
1.1 WHAT IS PLUTONIUM?
Radioactive metal * Plutonium is a radioactive element. Pure plutonium is a silvery-white metal. Most plutonium is found combined with other substances, for example, plutonium dioxide (plutonium with oxygen) or plutonium nitrate (plutonium with nitrogen and oxygen). Plutonium is usually measured in terms of its radioactivity (curies or becquerels). Both the curie (Ci) and the becquerel (Bq) tell us how much a radioactive material decays every second.
Exists in various forms called isotopes * The most common plutonium isotope is plutonium-239.
Plutonium is not stable * Each radioactive isotope of an element constantly gives off radiation, which changes it into an isotope of a different element or a different isotope of the same element. This process is called radioactive decay. Plutonium-238 and plutonium-239 give off alpha particles (sometimes referred to as alpha radiation) and transform into uranium-234 and uranium-235, respectively. The half-life is the time it takes for half of the atoms of a radionuclide to undergo radioactive decay and change it into a different isotope. The half-life of plutonium-238 is 87.7 years. The half-life of plutonium-239 is 24,100 years. The half-life of plutonium-240 is 6,560 years.
Produced in nuclear power plants and used in nuclear weapons and batteries * Very small amounts of plutonium occur naturally. Plutonium-239 and plutonium-240 are formed in nuclear power plants when uranium-238 captures neutrons. Plutonium is used to produce nuclear weapons.
Plutonium-238 is used as a heat source in nuclear batteries to produce electricity in devices such as unmanned spacecraft and interplanetary probes.
More information about the properties and uses of plutonium can be found in Chapters 4, 5, and 6.
1.2 WHAT HAPPENS TO PLUTONIUM WHEN IT ENTERS THE ENVIRONMENT?
Released during testing of nuclear weapons * Plutonium released during atmospheric testing of nuclear weapons, which ended in 1980, is the source of most of the plutonium in the environment worldwide. The plutonium released during these tests was deposited on land and water. The small amount that remains in the atmosphere continues to be deposited as it slowly settles out.
* Plutonium is also released to the environment from research facilities, waste disposal, nuclear fuel reprocessing facilities, nuclear weapons production facilities, and accidents at facilities where plutonium is used.
1. PUBLIC HEALTH STATEMENT
Deposited in water or soil * Plutonium can be transported in the atmosphere usually when it is attached to particles in the air. It can be deposited on land or water by settling or by rain. Plutonium can stick to particles in soil, sediment, and water. Plutonium isotopes will undergo radioactive decay in the environment.
For more information on plutonium in the environment, see Chapter 6.
1.3 HOW MIGHT I BE EXPOSED TO PLUTONIUM?
You may be exposed to plutonium by breathing air, drinking water, or eating food containing plutonium; however, the levels of plutonium in air, water, soil, and food are very low.
Soil * Average plutonium levels in surface soil from fallout range from 0.01 to 0.1 picocuries (pCi) per gram of soil (1 picocurie equals one-trillionth [10-12] of a curie).
Air * Plutonium concentrations in air are generally low. Baseline plutonium-239 concentrations in air ranging from 1.6x10-6 to 3.8x10-6 pCi per cubic meter of air (pCi/m3) have been reported.
Workplace * Persons who work at nuclear fuel and weapons production facilities have a greater chance of being exposed than individuals in the general population.
Accident * You could be exposed to plutonium if there was an accidental release of plutonium during use. It is very unlikely you would be exposed as the result of a traffic accident or disposal. Plutonium transport containers are virtually indestructible by accident or fire. The disposal site is deep underground and away from the public.