What is tritium and how do people become exposed to tritium?
Is the radiation dose from tritium any different than the dose from natural background radioactivity or medical instruments?
- Tritium is a radioactive form of hydrogen. It is produced naturally in the upper atmosphere when cosmic rays strike atmospheric gases. It also is a byproduct of electricity generation at nuclear power plants, and it is produced commercially in concentrated quantities for use in self-luminescent devices such as exit signs, aircraft dials and wristwatches.
- Tritium emits a weak form of radiation. The radiation emitted from tritium is a low-energy beta particle that is similar to an electron. Moreover, the tritium beta particle does not travel very far in air and cannot penetrate the skin.
- Tritium is almost always found as a liquid and primarily enters the body when people eat or drink food or water containing tritium or absorb it through their skin. People can also inhale tritium as a gas in the air.
- Once tritium enters the body, it disperses quickly and is uniformly distributed throughout the soft tissues. Half of the tritium is excreted within approximately 10 days after exposure.
- Everyone is exposed to small amounts of tritium every day, because it occurs naturally in the environment and the foods we eat. Workers in federal weapons facilities; medical, biomedical, or university research facilities; or nuclear fuel cycle facilities may receive increased exposures to tritium.
How do you measure tritium?
- The type of radiation dose from tritium is the same as from any other type of radiation, including natural background radiation and medical administrations.
- The tritium dose from nuclear power plants is much lower than the exposures attributable to natural background radiation and medical administrations.
What is the industry doing about tritium leaks and spills at nuclear power plants?
- A standard unit for measuring the amount of radioactivity is the curie. For perspective, the amount of tritium in the groundwater at the nuclear power plant with the highest and most extensive levels of tritium is far less than the amount of tritium in a single self-luminous exit sign. Many industrial-grade exit signs contain 10 to 20 curies of tritium gas.
- By comparison, the average concentration of tritium in groundwater at nuclear plants is at or below 20,000 picocuries per liter, the Environmental Protection Agency's Standard for tritium in drinking water.
*NEI and NRC
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- As with any industrial facility, a nuclear power plant may deviate from normal operation with a spill or leak of liquid material. However, the plant design and the Nuclear Regulatory Commission's inspection program both provide reasonable assurances that safety limits will be met - even in abnormal situations.
- The industry routinely monitors the environment around the plant, including surface and ground water; shoreline sediments; and samples from food sources such as milk, fish and other animals. The industry must report annually on the results of this monitoring to the Nuclear Regulatory Commission. This information also is provided to state agencies and is made publicly available.
- The industry launched an initiative in 2006 to improve the management of situations involving radiological releases to groundwater. Every company that operates a U.S. nuclear power plant has committed to inform local, state and federal authorities of an unplanned release even if it is below the threshold for reporting to Nuclear Regulatory Commission the .
- The nuclear energy industry is committed to operating its plants safely and to protecting the environment. A combination of plant design, control systems and radiation monitoring helps prevent unplanned radioactive releases and helps control and contain them in the event that they should occur.
- If nuclear plant operators detect elevated levels of tritium, they take steps to identify the cause of the elevated presence and control it. In fact, there has been no instance at nuclear power plants in which tritium has caused a significant exposure to the public.