Discharge of radioactive water of the Fukushima Daiichi Nuclear Power Plant
[5][6] Since then, contaminated water has been pumped into storage units and gradually treated using the Advanced Liquid Processing System (ALPS) to eliminate most radionuclides,[3][7] except notably tritium with a half-life of 12.32 years.
"Continuing indirect releases of about 5 to 10 TBq [terabecquerel, 1012 Bq] of Caesium-137 per year via rivers draining catchment areas", according to the UNSCEAR report in 2020.
[18][19] TEPCO estimated that a total of 520,000 tons of untreated radioactive water had escaped into the ocean before it could place silt fences to contain further spills.
[5] After repeated denials,[22] the operator of the nuclear plant, Tokyo Electric Power Company (TEPCO), finally admitted on 22 July 2013 that leaks to groundwater had been happening.
[24][25][verification needed] For instance, in 2014, TEPCO blamed its own measuring method and revised the strontium in a groundwater well in July 2013 from 900,000 Bq/L to 5,000,000 Bq/L, which is 160,000 times the standard for discharge.
TEPCO has since tried to stem or divert the inflow of groundwater to the damaged reactor sites and prevent contaminated water from escaping into the ocean.
The company estimated that 5.5 tonnes of water, which potentially contained 22 billion becquerels of radioactive materials such as caesium and strontium, had escaped from an air vent, pooled outside and seeped into the surrounding soil, but did not leave the plant compound.
The contaminated water is pumped out and combined into the reactor-cooling loop, which includes stronium–cesium removal (KURION, SURRY) and reverse osmosis desalination processes.
[30][31] In October 2012, TEPCO introduced the "Advanced Liquid Processing System" (ALPS, Japanese: 多核種除去設備), which is designed to remove radionuclides other than tritium and carbon-14.
[42] Some scientists expressed reservations due to potential bioaccumulation of ruthenium, cobalt, strontium, and plutonium, which sometimes slip through the ALPS process and were present in 71% of the tanks.
[46][47] Mainichi Shimbun criticized the government for showing "no sincerity" in "unilaterally push[ing] through with the logic that there will no longer be enough storage space"[48] On 13 April 2021, the Cabinet of Prime Minister Suga unanimously approved that TEPCO dump the stored water to the Pacific Ocean over a course of 30 years.
NRA also set up a system to monitor the radionuclide concentration in ALPS-processed water in order to verify TEPCO's readings.
[12] On 22 August 2023, Japan announced that it would start releasing treated radioactive water from the tsunami-hit Fukushima nuclear plant into the Pacific Ocean in 48 hours, despite opposition from its neighbours.
[54][55] Japan says the water is safe after the use of Advanced Liquid Processing System (ALPS), which removes nearly all traces of radiation from the wastewater, with tritium being the primary exception to this.
As a result, Japan has committed to diluting the water in order to bring levels of tritium below the regulatory standards set by the International Atomic Energy Agency.
The International Atomic Energy Agency has stated that the plan meets safety standards, but critics contend that more studies need to be done and the release should be halted.
[60] The Japanese Fishery Agency reported that fish caught 4 km away from the discharge pipe contained no detectable amounts of tritium.
For comparison, the La Hague nuclear processing site in France released 11,400 TBq of tritium in the year of 2018.
[126] "There is consensus among scientists that the impact on health is minuscule, still, it can't be said the risk is zero, which is what causes controversy", Michiaki Kai, a Japanese nuclear expert, told AFP.
[127] David Bailey, a physicist whose lab measures radioactivity, said that with tritium at diluted concentrations, "there is no issue with marine species, unless we see a severe decline in fish population".
[120] Ferenc Dalnoki-Veress, a scientist-in-residence at the Middlebury Institute of International Studies at Monterey, said regarding dilution that bringing in living creatures makes the situation more complex.
[122] Robert Richmond, a biologist from the University of Hawaiʻi, told the BBC that the inadequate radiological and ecological assessment raises the concern that Japan would be unable to detect what enters the environment and "get the genie back in the bottle".
[120] Dalnoki-Veress, Richmond, and three other panelists consulting for the Pacific Islands Forum wrote that dilution may fail to account for bioaccumulation and exposure pathways that involve organically-bound tritium (OBT).
