Tritium in Water.
The IAEA, which has a permanent office at Fukushima, said an “independent, on-site analysis” had shown that the tritium concentration in the water discharged was “far below the operational limit of 1,500 becquerels per litre (Bg/L)”.
The World Health Organisation’s limit for tritium in drinking water is 10,000 Bg/L.
Critics of the treated water discharge, from the Fukushima nuclear plant, say a lack of long-term data means it is impossible to say with certainty that tritium poses no threat to human health or the marine environment, even though Nuclear power plants worldwide have routinely discharged water containing tritium for over 60 years without apparent harm to people or the environment.
Tritium is produced naturally in the upper atmosphere when cosmic rays strike nitrogen molecules in the air, and gets into the oceans through rainfall.
Tritium is naturally present in surface waters at about 0.4–1.2 Bq/L.
Tritium is also produced during nuclear weapons explosions, and as a byproduct in nuclear reactors.
Some experts have pointed out that nuclear power plants in other countries, including China, have released diluted tritium into the sea for decades without incident.
“Nuclear power plants worldwide have routinely discharged water containing tritium for over 60 years without harm to people or the environment, most at higher levels than planned for Fukushima,” Tony Irwin, an honorary associate professor at the Australian National University, said.
China’s Fuqing power plant in Fujian province releases about three times more tritium into the Pacific than the planned Fukushima discharge.
China has condemned the discharge, with China’s foreign ministry said it was an “extremely selfish and irresponsible act”.
The Kori nuclear power plant in Busan in South Korea releases a similar amount to Fuqing. The South Korea government recently said it accepted the IAEA’s safety report approving the plan.
The La Hague reprocessing facility releases about 10,000 Terabecquerels of tritium per year (8,190TBq in 2008) into the English Channel, and there is no evidence of significant ecosystem impacts. The planned release from Fukushima of 22 Terabecqurels per year to the Pacific Ocean is about 450 times lower than the La Hague releases and 50 times lower than releases from the UK’s Sellafield facility.
Atmospheric levels of tritium peaked in the 1960s, before the ban on testing nuclear weapons, and according to the latest estimates there is less than 20 kg of tritium on Earth as at 2022.
Sources:
https://www.epa.gov/radiation/radionuclide-basics-tritium
Atmospheric levels peaked in the 1960s, before the ban on testing nuclear weapons, and according to the latest estimates there is less than 20 kg (44 pounds) of tritium on Earth right now.
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