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Nuclear regulator launches study of sea contamination off Fukushima


Japan's Nuclear Regulation Authority on Wednesday started an investigation of the contamination of the seafloor off the coast of Fukushima Prefecture to check the impact of the 2011 Fukushima Daiichi nuclear power plant disaster.

The study of the density of radioactive cesium is being conducted with the aid of a ship that trails a radiation counter along the seafloor and will cover an area of about 1,000 square kilometers.

Studies in the past have focused on certain points in the Pacific Ocean around the radiation-leaking Fukushima plant, while the NRA's investigation aims to analyze the spread of contamination through a broader investigation.

The results will be compiled by March next year and the data could be used to confirm the safety of marine products.

The NRA has outsourced the project to a team involving the University of Tokyo and the National Maritime Research Institute.

The team from early Wednesday started a sonic survey and other activities to check the geological formation of the seafloor. It will start measuring the density of cesium between November and February.

The survey will cover an area within 20 kilometers off the coast and 50 km north and south of the Fukushima Daiichi plant.

An official of the NRA secretariat said that such an investigation needs to continue for at least three years in order for the changes in the spread of contamination to be properly recorded.

Highly radioactive water is increasing daily at the plant as a result of water continually being pumped into the three crippled reactors. The liquid is kept at hundreds of huge tanks set up at the site, posing a risk of leaks.

Most recently, 300 tons of contaminated water was found to have escaped from one of the tanks, part of which could have flowed into the ocean through drainage channels.

All fisheries operations off the coast of Fukushima have been suspended from September amid signs of further contamination stemming from the nuclear complex.

But on Wednesday, a local fisheries cooperative covering the southern part of the prefecture decided to start what it terms a trial operation from Sept. 26. The operation limits the type of marine products to be fished and only allows those confirmed to be safe to be shipped.

The decision came after the cooperative postponed its plan to start from Sept. 5 its first trial operation after the Fukushima nuclear accident.

Another fisheries cooperative covering the northern part of the prefecture is also seeking to resume its trial operation from Sept. 26.