Apr 14 (NHK) - Tritium is generated in the process of ordinary operations at nuclear power facilities. The radioactive substance is diluted before being released into the sea or the air based on the criteria of a given government.
Nuclear power plants in Japan release water containing tritium into the sea after ensuring that the concentration does not exceed 60,000 becquerels per liter.
The Fukushima Daiichi plant released more than 2 trillion becquerels of tritium in 2010, the year preceding the nuclear accident there.
Tritium is also released into the sea or the air from nuclear facilities abroad according to government-set standards.
The amount of the material released differs depending on the type of facility.
Japan's industry ministry says the Daya Bay nuclear power plant in China, which is the same type of facility as those in Japan, released 42 trillion becquerels in 2002.
The Callaway plant in the United States, another facility of the same type as those in Japan, released the same amount that year.
The Darlington plant in Canada released 241 trillion becquerels in the form of liquid, and 254 trillion becquerels in the form of gas in 2015.
At the Wolseong nuclear power plant in South Korea, 17 trillion becquerels were released in the form of liquid, and 119 becquerels in the form of gas in 2016.