Radioactive Waste Woes in Japan

Tuesday, August 2, 2011 @ 03:08 PM gHale

With everything the country has been going through, local governments in Japan remain troubled over how to handle waste containing radioactive cesium, including sludge discharged from water and sewage treatment plants, and ash.

More than 120,000 tons of such radioactive waste is in storage in Tokyo and 13 prefectures in the Tohoku and Kanto regions, according to surveys by the Health, Labor and Welfare Ministry and The Yomiuri Shimbun.

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Although the government aims to establish a new law to create a government-led framework to dispose of the waste, it is uncertain how quickly this will resolve the problem.

About 180 tons of sludge is at a disposal site in Fukushima as of Wednesday. Sludge discharges when river water and sewage undergoes purification at treatment plants–water treatment plants discharge sludge containing mostly earth and sand, while sludge from sewage treatment plants contains domestic wastewater and excrement.

In a normal scenario, officials incinerate most of the sludge to reduce its volume, after which they bury it or recycle it into materials for cement.

At the disposal site in Fukushima’s Horikawacho district, sandbags weighing one ton each were recently piled up inside an outdoor tank about 5 meters deep and surrounded by concrete walls 15 centimeters thick.

The bags filled with dehydrated sludge containing radioactive cesium. Workers in protective suits lifted the bags into the tank with a crane.

The quantity of the radioactive sludge was increasing by about 14 tons a day, and according to workers, the 10 tanks at the site will be full by the end of the year.

Separately from the bags, about 5,000 tons of sludge containing higher levels of radioactive substances remain untouched in tanks. This is because official detected 446,000 becquerels of cesium per kilogram in the sludge in May, and about 300,000 becquerels at a later date.

The government presented a preliminary guideline for handling such radioactive waste in June. It asked local governments to take measures to block radiation rays if radioactivity exceeds 100,000 becquerels, but it does not give directions as to final disposal methods.

An official of the city government said: “Many residents have expressed fears about the effects of radioactive rays and complained about the odor. We want the government to indicate how we should handle the waste as soon as possible.”

The guideline stipulates that if the radioactivity is less than 100,000 becquerels, waste can temporarily store at controlled landfill sites where hazardous substances will not leak into soil.

But little progress has occurred in securing such disposal sites to accommodate radioactive waste.

At a water purification center in Maebashi, official detected 41,000 becquerels of radioactivity in ash in May. The center is storing 190 tons of radioactive waste.

However, there is not a controlled disposal site in Gunma Prefecture that fulfills the guideline’s requirement for how far such a site must be from residential areas.

A law for regulating nuclear reactors and other facilities stipulates that if the radiation level in finished products is less than 100 becquerels, sludge and ash with radioactive substances can be mixed into materials for cement.

However, companies producing the recycled materials have become nervous. They will not accept sludge or ash unless the radiation level at the time of delivery is less than 100 becquerels.

The companies are especially reluctant to accept ash, which contains higher levels of radioactivity than sludge.

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