Latest news from Fukushima, they have found hotspots at 10 Seiverts an hour. What's the context here? Maximum safe annual exposure for a worker at the Tepco site was raised to 250 milliSeiverts a year, from the original non-emergency 100 milliSeiverts a year.
Peter Burns, former chief executive officer of the Australian Radiation Protection and Nuclear Safety Agency, says given the scale of the Fukushima emergency, the high reading is to be expected.
"The levels reported of 10 sieverts per hour are very high levels and it's going to be very difficult to manage workers going into those areas and doing operations," he said.
"To put the 10 sieverts into context, that 10 sieverts is actually a lethal dose of radiation. So you can't afford to be exposed for more than a few minutes at those levels.
"It means you're directly exposed to fuel rods in the reactors or the spent fuel ponds very closely and while it's possible to get to those levels it means there is very little shielding going on there."
My calculation would be that you would get the yearly limit in two and half minutes, which means that manual work is not going to solve the Fukushima clean up.
In fact, it's going to take decades, say Japanese sources. Now, the next fly to swallow is the idea that the safe zone round this mess is 20 km, which is barely credible. so, what do you do if you have to evacuate a large portion of the habitable land of a densely populated island, during a decade long clean up operation?
This one will be a long term one to watch.