Tritium

Tritium is a radioactive form of hydrogen that occurs both naturally and as a by-product in nuclear reactors and tritium processing facilities. Tritium exposure can pose a health risk if it is ingested through drinking water or food, inhaled or absorbed through the skin in large quantities. 

The CNSC regulates releases of tritium by nuclear reactors and tritium processing facilities to ensure the health and safety of workers and the public, and the protection of the environment.

Quick Facts

• Tritium is a radioactive form of hydrogen that occurs both naturally—from interactions of cosmic rays with gases in the upper atmosphere—and as a by-product of the operation of nuclear reactors.
• Tritium is the only radioactive isotope (form) of the element hydrogen.
• Tritium atoms can replace hydrogen atoms in any molecule.
• Tritium exposure can pose a health risk if it is ingested through drinking water or food, inhaled or absorbed through the skin in large quantities. 
• Canadian-designed CANDU (CANada Deuterium Uranium) reactors produce more tritium than most other types of reactors because they use heavy water in their moderator and heat transport systems.
• There are 18 operating CANDU reactors in Canada.
• Tritium levels in public drinking water supplies near nuclear facilities are well below both Health Canada's drinking water quality guidelines of 7,000 Bq/L and the proposed guideline of 20 Bq/L made by the Ontario Drinking Water Advisory Council.
• The general population in Canada is not at risk from tritium intake since exposure levels are well below regulatory limits.
• For the general public, the Canadian radiation dose limit from regulated activities is 1 millisievert (mSv) per year over and above natural background levels. Natural background levels average 2–3 mSv.
• Tritium doses to members of the public around nuclear power reactors are very low (0.00045 to 0.0026 mSv/year). Tritium doses to members of the public around processing facilities are also very low (0.00001 to 0.0145 mSv/year).
• The radiation dose limit for nuclear energy workers is 50 mSv per year or 100 mSv over five years.
• The average occupational doses from tritium exposures in 2006 ranged from 0.07 to 0.26 mSv for workers at nuclear generating stations, and from 0.30 to 0.90 mSv for workers at processing and research facilities. In all cases, doses were far less than CNSC annual occupational dose limits.