KYODO NEWS - Jan 11, 2018 - 13:57 | All

The chief of Japan's nuclear regulator said Thursday water at the crisis-hit Fukushima Daiichi nuclear plant that contains radioactive tritium even after being treated should be released into the sea after dilution.

"We will face a new challenge if a decision (about the release) is not made within this year," Nuclear Regulation Authority Chairman Toyoshi Fuketa told a local mayor, referring to the more than 1 million tons of coolant water and groundwater that has accumulated at the facility crippled by the 2011 disaster triggered by a devastating quake and tsunami.

As local fishermen are worried about the negative impact from the water discharge, the Japanese government and Fukushima plant operator Tokyo Electric Power Company Holdings Inc. have not made a final decision on the treated water, which is currently stored in tanks.

In his meeting with Yukiei Matsumoto, mayor of Naraha town near the Fukushima plant, Fuketa said, "It is scientifically clear that there will be no influence to marine products or to the environment" following the water release.

The nuclear regulator chief underlined the need for the government and Tepco to quickly make a decision, saying, "It will take two or three years to prepare for the water release into the sea."

At the Fukushima plant, toxic water is building up partly because groundwater is seeping into the reactor buildings to mix with water made radioactive in the process of cooling the damaged reactors.

Such contaminated water is treated to remove radioactive materials but tritium, a radioactive substance considered relatively harmless to humans, remains in the filtered water as it is difficult to separate even after passing through a treatment process.

At other nuclear power plants, tritium-containing water is routinely dumped into the sea after it is diluted. The regulator has been calling for the release of the water after diluting it to a density lower than standards set by law.

With limited storage space for water tanks, observers warn tritium could start leaking from the Fukushima plant.

On March 11, 2011, tsunami inundated the six-reactor plant, located on ground 10 meters above sea level, and flooded the power supply facilities.

Reactor cooling systems were crippled and the Nos. 1 to 3 reactors suffered fuel meltdowns in the world's worst nuclear catastrophe since the 1986 Chernobyl disaster.