8 Juillet 2014
TOKYO (Kyodo) -- Nuclear regulators expressed strong concern Monday about a delay in Tokyo Electric Power Co.'s plan to freeze highly toxic water building up in underground trenches at its crippled Fukushima Daiichi nuclear site, amid fears it could flow into the ocean and spread pollution.
The problem of the contaminated water being pooled in the trenches -- resulting from cooling water for reactors that suffered meltdowns in the 2011 Fukushima nuclear crisis -- is seen as one of the most urgent tasks TEPCO needs to address.
According to the utility, a total of some 11,000 tons of highly radioactive water has flowed into the trenches through the Nos. 2 and 3 reactor turbine buildings.
Before pumping out the water, the operator has inserted frozen ducts to try to freeze some of the water near joint parts of the No. 2 reactor turbine building and the trenches -- where pipes and cables are stored -- to stop further inflow, but the water has not fully frozen after more than two months.
At a meeting Monday, Nuclear Regulation Authority Commissioner Toyoshi Fuketa urged TEPCO officials to review its plan as soon as possible and propose additional measures to successfully freeze the water.
TEPCO blamed the fluctuating water levels in the tunnels for preventing it from freezing, but the regulatory officials questioned the contention and told the company to investigate other possibilities.
Fuketa said earlier that the radioactive water in the trenches is the "biggest concern" among challenges facing workers at the Fukushima plant.
A glitch in the process has also raised concern about TEPCO's plan to build a massive underground ice wall around the complex's four reactors to address the buildup of toxic water, as similar technologies are used for the wall.
TEPCO pressed to make sure ice wall works
Tokyo Electric Power Company is under pressure to make sure that its plan to install "frozen walls" to halt the flow of radioactive water at the crippled Fukushima Daiichi nuclear power plant actually works.
Officials of the Nuclear Regulation Authority, or NRA, expressed their concern at a meeting on Monday.
TEPCO began work in April to create a wall of ice between the basement of the No.2 reactor building and its utility tunnel.
The idea was to prevent highly radioactive water in the reactor building from flowing into the tunnel, where the runoff could become mixed with groundwater and end up in the sea.
The wall of ice was supposed to be in place in May, but the structure remains incomplete.
TEPCO officials told the NRA that currents in the water in the tunnel are preventing it from freezing, and that they'll have to put off pumping out radioactive water from the tunnel for about 3 months.
NRA officials urged the utility to come up with concrete measures by the end of July to complete the ice wall.
NRA officials also expressed concern that similar problems may hamper the freezing of soil around 4 reactor buildings at the plant. The massive underground wall is supposed to prevent groundwater from flowing into the buildings.