Japan, with US help, was getting ready to forge huge nuclear arsenal

... and also for War

Since the Reagan presidency the USA, as well as Great Britain and Canada, helped Japan to circumvent legality in order to mass up enough plutonium to develop a nuclear arsenal bigger than those of China, India and Pakistan combined.

The whole nuclear energy program, now in dire straits and threatening the very viability of the country as such, was in fact a gigantic cover up intended to hide the nuclear weapons program, something that Japan secretly ambitioned since WWII.

The use of MOX (mixed plutonium-uranium fuel) was the perfect excuse for this accumulation of plutonium, which would allow Japan to develop nuclear weapons in no time would the need arise. It was also a convenient way for other nuclear states such as France to get rid of their nuclear wast, which would be "recycled" in Japan and not anymore be a problem at home.

A long detailed article on this process, culminating in the Fukushima catastrophe, is available at the National Security News Service (found via EneNews).

'Great Wall' to be built to contain the worst of Fukushima

July 2011 snapshot of this regularly updated radiation map

Fukushima Diary mentions today that a 88km long wall will be built around the worst damaged area near Fukushima Daiichi.

Finally the Japanese Government seems to have accepted that the severity of the disaster requires evacuations (a year too late but better late than never) and is proposing the following zoning:

>50mSv/year zone (~5.7 μSv/hr) - No entry zone, walled

20-50mSv/year zone - No living zone

~20mSv/year (~2.3 μSv/hr) zone - Advisory evacuation area

That means that much of the reddish area in the map would become inaccessible, however most of Fukushima city, Koriyama and the other cities along the Tohoku highway would only fall in the advisory evacuation area probably.

For more detailed maps see this September 2011 entry.

The max. recommended exposure for civilians (US standards) is anyhow 1 mSv/year. Background radiation can be slightly higher in some areas however. 20mSv/year is the max exposure theoretically allowed for nuclear workers. 

However the local authorities, specially the once populous Minamisoma city, just outside Fukushima Daiichi NPP, are reluctant to evacuate in most cases, giving the central government a pretext to delay all these measures.