Photo : Spent nuclear fuel in Reactor 3 pool in February 2021. [Link]
According to the report of Ministry of Economy, Trade and Industry in Japan, the current stored amount of Tritium in Fukushima nuclear plant takes 39 years to be discharged to the Pacific, and it increases faster than being discharged.
In Fukushima nuclear plant, Tepco is still cooling the molten fuel by water without a circulating coolant system. The water which directly touched the fuel is mixed with the natural ground water inside the crippled reactor buildings and Tepco is continuously pumping it up. According to Tepco, such contaminated water increases by 180 m3 everyday.
Tepco is reportedly filtering the radionuclides from the water by applying Advanced Liquid Processing System (ALPS) but still high level of radioactive water, Tritium, remains in the water.
The stored amount of Tritium water is currently over 1.2 million m3 and it is continuously growing. Tepco is estimated to run out of the storage tanks by the summer of 2022.
On the 13th of April, 2021, the government of Japan decided to discharge the contaminated water to the Pacific in two years by diluting it 100 times with seawater.
On the 30th of July, 2021, Nuclear Regulation Authority in Japan decided the annual limit of the total amount of Tritium to be discharged at 22 trillion Bq, which was the safety standard of Fukushima nuclear plant before the accident. However, according to Ministry of Economy, Trade and Industry in Japan, the total amount of Tritium stocked in the tanks is 16 grams, which is 860 trillion Bq up to October 2020. It is going to take 39 years to dilute and discharge to the Pacific. Additionally, 50,000~60,000 m3 of contaminated water is annually produced and the average density of Tritium is 730,000,000 Bq/m3. It is calculated that approximately 36.5 trillion Bq of Tritium is annually produced. Thus even after discharging the maximum amount under the safety limit, which is 22 trillion Bq, still 14.5 trillion Bq of Tritium will end up being piled on land every single year.
The current technology to extract Tritium from water can only be applied to the density from 0.1 to 1.5 trillion Bq / L and the processed water still contains Tritium more than the contaminated water in Fukushima plant in density.