Tokyo Electric Power (Tepco), operator of the Fukushima nuclear plant, is currently flushing water to keep the reactors' temperature low enough in an effort to avoid radioactive releases. Radioactivity of the used water is reduced through a special treatment procedure, however current technology cannot remove a relatively harmless radioactive isotope called tritium. Tepco now wants to evaporate huge amounts of that water, raising concerns over the particular practice.
Contaminated and treated water was so far been kept in hundreds of tanks, leading the plant operator to consider releasing the tritium-laced water into the ocean, a practice commonly adopted in the case of normally operating plants. However, fishermen opposition has led the government to consider the evaporation method or the underground storage according to chief decommissioning officer Naohiro Masuda.
The evaporation method has also been applied following the Three Mile Island disaster in the USA, however the amounts of tritium-laced water were significantly smaller. Dale Klein, an outside adviser to Tepco, said that considering the huge amounts of contaminated water, even it is evaporated, it will condense and fall back as rainwater, stressing out that there is no safety enhancement. Klein also expressed his concern over Tepco's current practice of storing the water in tanks, characterizing it as "asking for failure".