The Japanese government has just started a new experiment in the very highly contaminated Iitate-mura in Fukushima Prefecture where the soil contamination exceeds 50,000 becquerels/kg of radioactive cesium, with a host of other nuclides including strontium and neptunium which has since decayed into plutonium.
What's the experiment? To burn the radioactive soil to reduce the bulk for disposal.
What's this Japanese obsession with "decontamination" and with "incineration"? Do they think they can somehow "purify" the radioactive fallout by burning? (Hint: this is a rhetorical question. Answer is yes of course.)
The nuclear researchers at the government's JAEA seem to think burning the soil will revive the soil.
It will kill the soil.
From Kyodo News Japanese (10/26/2011):
On October 26, Japan Atomic Energy Agency (located in Tokai-mura, Ibaraki Prefecture) showed off its new experiment to see if radioactive cesium could be effectively removed by burning the farm soil in Iitate-mura in Fukushima Prefecture. The experiment is aimed at reviving the farm fields contaminated by the Fukushima I Nuclear Power Plant accident.
It is part of the soil remediation technology development as assigned by the Ministry of Agriculture, Forestry and Fisheries. JAEA and National Agriculture and Food Research Organization (in Tsukuba City, Fukushima Prefecture) are jointly conducting the research. The result of the experiment will be known in 2 to 3 weeks.
According to the Ministry of Agriculture, if all the farm soil with 5000 becquerels/kg and higher [of radioactive cesium] is removed in Fukushima Prefecture, it would fill 2 to 3 Tokyo Domes, or about 3 million tonnes. How to dispose the removed soil is a big issue.
Let's assume the lowest number, 5,000 becquerels/kg of radioactive cesium in the Fukushima farm soil. 1 tonne is 1000 kilograms. So,
1 tonnes contains: 5 million becquerels of radioactive cesium
3 million tonnes contains: 1.5 x 10^13, or 15 terabecquerels, or 15,000,000,000,000 becquerels.
If the national government's much-publicized past experiments (like planting sunflowers to absorb radioactive materials in soil) in Iitate-mura are any indication, this one may also fail.
Besides, by strongly encouraging farmers outside the no-entry evacuation zone and the planned evacuation zone (like Iitate-mura) in Fukushima to grow crops as usual, the soil was probably turned deep, mixing radioactive materials with deeper, clean soil. So, removing the top 5 centimeters are likely to do hardly anything other than making people feel good that they have done the "decontamination".
There are areas and spots with high radiation outside Fukushima Prefecture, but those are none of the concern for the national government, although it has said it may consider the national-level decontamination for the areas with expected annual radiation exposure (external only) of more than 1 millisievert.