The Environment Ministry on Aug. 27 dramatically lowered the level of radiation-contaminated ash that can be disposed of at municipal disposal plants, while requiring strict measures to prevent the ash from contaminating groundwater.
The Environment Ministry on Aug. 27 dramatically lowered the level of radiation-contaminated ash that can be disposed of at municipal disposal plants, while requiring strict measures to prevent the ash from contaminating groundwater.
Under the new guidelines, to be given to municipalities, ash contaminated with 100,000 becquerels per kilogram or less of radioactive cesium can be buried at ordinary final processing plants, up from the previous 8,000 becquerels or less per kilogram level.
Municipalities will be required to take strict measures, including cementing the tainted ash, placing it in a durable container, setting up a layer to avoid water seepage and using roofed disposal facilities. At the ministry experts' meeting on Aug. 27, some suggested that those four measures be adopted for security reasons.
The new guidelines raise the provisional level approved in June that ash contaminated with 8,000 or less becquerels of radioactivity per kilogram can be disposed of by municipalities.
In June, the ministry said if ash contains 100,000 becquerels or less radioactivity per kilogram, residents' safety would not be threatened.
However, at the same time it set a provisional level of 8,000 becquerels or less radioactivity per kilogram that could be treated at municipal disposal plants, in consideration of the health of plant workers.
After the release of the guidelines, ash containing more than the permissible level were found at incineration plants in seven prefectures, including Tokyo and Chiba prefectures, making disposal more difficult for municipalities.
The government will continue to discuss methods for the treatment and disposal of ash containing more than 100,000 becquerels per kilogram of radiation.