Thousands of tonnes of contaminated water are to be discharged from Fukushima Daiichi to give plant operators a better chance to manage more serious contamination.
Tokyo Electric Power Company (Tepco) has faced increasing problems with large bodies of water at the nuclear power plant site, some of which have significant levels of radioactivity. While turbine buildings have flooded basements, cabling trenches are also full of water. Of particular concern are the waters in unit 2, where dose rates at the surface reach over 1000 millisieverts per hour. Efforts are ongoing to plug a 20 centimetre crack at unit 2 that was allowing contaminated water to flow directly into sea.
Some 134 samples of various foods from twelve prefectures around Japan have been taken in the last three days. They included a range of fruit, vegetables and milk as well as beef and pork. All but one showed either no detection of iodine-131 or caesium-137 or levels within limits. The single affected food was shiitake mushrooms from Fukushima prefecture.
Now, the Japanese government has approved Tepco's plan to move the most contaminated water to the central radioactive waste treatment facility. This means that the stocks of water already present there have to be displaced, taking with them low levels of radioactivity.
Some 10,000 tonnes of this will be allowed to enter the sea, Tepco said, as well as 1500 tonnes from the sub drain pits of units 5 and 6. Subsurface water is running into the buildings of those units and Tepco said this could eventually affect safety equipment.
The company calculates that a person who ate fish and seaweed from the nearby sea every day would have an additional radiation dose of 0.6 millisieverts per year, but did not say how long this would continue. The additiona dose compares to the 2.4 millisieverts people receive from natural sources each year.
Researched and written
by World Nuclear News