“Plans are being made to use dry ice blast for cleaning radiation contamination on roads which was caused by the incident at the Fukushima Nuclear Power Plant. Talks regarding the details have not made any headway, however.

Dry ice blasting is a cleaning by spraying dry ice in the form of pellets to the material targeted at a set pressure. When the pellets strike the material energy is created chiefly at the point of impact and but also in the periphery. Surface of the material is then lifted away by this energy. What is also based on the use of this same principle is sandblasting but with this some sand remains after cleaning. Contaminants can be held down after cleaning because dry ice sublimates.

The dry ice blasting equipment used in the cleaning business planned and operated by general construction companies is an integrated vehicle mounted cleaning equipment. The dry ice blasting equipment and dust collector mounted on the truck are connected to the targeted contaminated road in front of the truck through pipeline. The cleaning equipment works with activating switch, and while moving ahead automatically the dry ice pellets which are supplied from the blast equipment at a pressure of 0.7MPa, are sprayed onto the road, and removal is conducted. The waste material taken off from the road at that time is sucked up by the dust collector operating like a vacuum cleaner. About 70% of the radiation can be removed by using this facility.

The facility, operating 8 hours a day, can conduct cleaning of 10 m from a road of normal width. The amount of pellets consumed at that time comes to 300-480 kg. Trials are currently being conducted regarding specific methods of operation. During operation a considerable amount of dry ice will be required as it is assumed that several such units will be used each day. Three qualities are required for the pellets, these being uniformity of size, strength, and no moisture. With pellets which do not have these qualities prices could arise such as clogging inside the facility, a lowering of the cleaning effectiveness, or residual contaminants.

These facilities could become the source of large consumption of dry ice are yet to be scheduled to go into operation due to the fact that the government’s plans for recovery for the damaged area by the Fukushima incident are just not moving along. For this reason no specific schedule for operation has been made. Also the problem remains as to how to treat the radioactive material sucked up into the dust collector when cleaning is carried out”