The Environment Ministry released a road map on Jan. 26 for decontaminating areas around the Fukushima No. 1 nuclear power plant, hoping to provide encouragement for residents forced to flee the radioactive fallout from the accident.
“I hope the evacuees will be able to return to their homes as early as possible,” Environment Minister Goshi Hosono told reporters.
But not all evacuees received a timeline for when they might eventually be allowed return to their homes. Given the enormity of the decontamination project, the road map showed that the most dangerous areas will be virtually abandoned for the time being and that much of the plan could end up depending largely on natural decreases in radiation levels.
According to the document, the central government will be directly involved in decontamination work in the no-entry zone within a 20-kilometer radius of the nuclear plant and the “planned evacuation zone” extending beyond that radius in the northwest direction.
In areas with annual radiation doses below 50 millisieverts at a height of 1 meter above ground, work should be completed by March 2014 to reduce the level to 20 millisieverts or less, making those areas habitable, according to the road map.
The ministry, however, decided that it would be difficult to achieve that reduction goal in areas with annual doses exceeding 50 millisieverts.
The Environment Ministry used a three-way zoning structure based on radiation levels to determine priority for decontaminating land plots other than forests–including residential land for about 60,000 households, farmland, commercial and industrial estates.
For “zones being prepared for the lifting of the evacuation order,” with annual doses of 20 millisieverts or less, explanatory meetings will be held for evacuees from those areas as early as this month on steps for their return home.
Owners and occupants of privately owned land will be asked to approve workers’ entry into and decontamination of their properties.
The efforts will start in areas with annual doses of 10-20 millisieverts, where a sizable reduction can be expected and the reduction goal is 10 millisieverts or less. A stricter reduction target of 1 microsievert per hour (corresponding to 5 millisieverts per year) or less will apply to schools.
Decontamination work, including soil removal, will begin in July and hopefully be finished by December 2012, according to the road map. That time frame may provide an indication of when the evacuation order will be lifted.
Owners’ approval will be sought and decontamination efforts will start in June for areas with annual doses below 10 millisieverts.
Under the road map, decontamination will be finished by March 2013 in areas between 5 and 10 millisieverts and by March 2014 in areas between 1 and 5 millisieverts.
March 2014 is also the target date for completing decontamination in the “no-residence zones,” or areas with annual doses between 20 and 50 millisieverts. The target for dose reduction there is 20 millisieverts or less per year.
But for the “no-return zones,” where annual doses exceed 50 millisieverts, the road map provided no specific schedule for decontamination work, leaving room for abandonment of efforts as an option. Only pilot decontamination programs will be conducted in those zones.