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Radioactive water fuels fresh Fukushima fears
Publication Date : 06-08-2013
Fresh worries have surfaced over the stricken Fukushima nuclear plant in Japan, where there is an increasing risk of radioactive ground water spilling over barriers meant to contain it and into the sea.
But officials of Tokyo Electric Power (Tepco), which manages the facility, are quick to dismiss any concerns of a health threat.
The Nuclear Regulation Authority (NRA), Japan's nuclear watchdog, has raised doubts about Tepco's plan to construct underground walls to prevent the contaminated water at the Fukushima No.1 plant from reaching the Pacific Ocean. The plant is located about 210km north of Tokyo.
The reason is that water in observation wells has already risen to a level higher than the top of the proposed underground walls.
According to the influential Asahi Shimbun daily, if water levels continue to rise at the present speed, the radioactive water could rise to the surface in about three weeks.
Officials of Fukushima prefecture, which hosts the nuclear plant, said consumers need not be worried by the latest reports.
"Nothing has changed. All produce remains safe to eat as it must clear radiation tests mandated by the government," said Isao Otomo, who heads a division overseeing the distribution of farm products, in response to a query from The Straits Times.
"The problems reported at the nuclear plant are confined to the plant and not elsewhere in the prefecture," he stressed.
Concerns about fish caught in contaminated water are also unfounded. "Fishermen can only fish in open waters far from shore. In any case, everything they catch must be tested for radiation before it can go to market," Otomo added.
Apart from no-go zones within roughly 20km of the stricken plant, travel within the prefecture is unrestricted.
Still, the NRA is not the only one critical of Tepco. The Japanese media and citizens' groups have also blasted the utility's secrecy, while foreign experts recently took it to task for its lack of transparency over radioactive leaks.
Last month, the former head of the US Nuclear Regulatory Commission, Dale Klein, told a nuclear reform monitoring panel here that included Tepco's chief executive that "you (Tepco) do not know what you are doing".
Last week, Tepco also surprised the Japanese with the revelation that between 20 trillion and 40 trillion becquerels of tritium could have been washed out to sea from the crippled plant over a period of 26 months from June 2011 to July this year.
Tritium is a radioactive isotope of hydrogen and normally measured in becquerels. It is dissolved in water when released from a nuclear plant.
The 40 trillion figure cited by Tepco arises from calculations which assume that 400,000 litres of water are used every day to cool the reactors and that each litre of water contains 500,000 becquerels of tritium.
The lower 20 trillion figure comes from another method of estimation using seawater, which contains a lower level of tritium.
Tepco, however, pointed out that the maximum estimated outflow comes to about 20 trillion becquerels of tritium a year, which is close to the normally allowed level of 22 trillion becquerels for all six reactors at the plant before the March 2011 disaster.
The problem was not the amount of tritium leaked, but that it was leaked into the sea in an uncontrolled manner, a Tepco official was reported as saying.