The Ministry of Economy, Trade and Industry estimates that discharging tritium in the contaminated water at the Fukushima No. 1 nuclear plant into the ocean is the fastest and least costly way of disposing of the radioactive material, it has been learned.
The ministry is set to present the estimate at an April 19 expert panel meeting. The ministry has been looking into ways to dispose of radioactive tritium, which cannot be removed by the plant's "ALPS" (Advanced Liquid Processing System) multi-nuclide removal equipment and has thus been accumulating in storage tanks on the plant premises.
While the expert panel will also present other methods, the ministry's estimate may affect the decisions of the government and plant operator Tokyo Electric Power Co. over the tritium disposal method.
The ministry had examined five tritium disposal methods, including burying it underground, vaporizing it, and releasing it into the atmosphere after reducing the tritium to hydrogen gas -- on top of the ocean release plan. For each of the five methods, the ministry calculated the time and cost required for disposal, based on an estimate of 800,000 metric tons of tritium-tainted water to be processed at the rate of 400 tons a day.
As a result, the ministry found that discharging tritium into the ocean would take up to seven to eight years and cost up to some 3.5-4.5 billion yen -- the least among the five methods, though the figures may vary depending on the concentration of tritium. Burying tritium underground, meanwhile, would require a maximum 76 years of management and would also be costly.
The ALPS system is capable of removing 62 types of radioactive materials, but not tritium.