Qantas is doing contingency planning for the evacuation of Australians from Tokyo if called upon by the Australian government.

However, so far the official Australian response, despite some emphatic urging by Foreign Minister Kevin Rudd that people should consider leaving now, is more measured than that of the US, which this morning urged its nationals to retreat at least 80 kilometres from the stricken Fukushima Daiichi nuclear power reactor complex 240 kilometres north-east of Tokyo.

In fact, Qantas flights from Tokyo are still showing seat availability in coming days.

But the precision of the US advice reflects the total breakdown of the protocol between nuclear treaty nations not to comment on each other’s nuclear regulatory affairs.  The Japanese authorities are sticking to a 20-kilometre exclusion zone in the open air or 30 kilometres for those who stay indoors. They are also refusing to budge on their claim of a level 4 nuclear crisis at the plant, despite now being contradicted by at least four nuclear treaty nations who have through their agencies described it as level 6, the same level first applied to the Chernobyl disaster of 1986, which was later raised to a level 7 event with global consequences and a need for concerted international action.

Overnight, the regulatory authorities of France, Germany, Switzerland and lastly the US have become the leading sources of accurate data and assessment of the situation at the six Japanese reactors that are collectively, in severe crisis and risk of total meltdowns.

Air France is operating two additional evacuation flights out of Tokyo on instructions from the French government, which like Germany, has told its nationals to leave.

The winds are currently forecast to blow directly  from Fukushima to Tokyo tomorrow.

The US Department of Energy and the US Nuclear Regulatory Commission have nuclear reactor-trained personnel at, but now presumably some distance from, Fukushima Daiichi.

The most urgent concerns, at least at this moment, concern reactor No.4, where the temperature monitor in the spent fuel rod cooling pool went off line yesterday after remaining at 84 degrees  throughout  Monday and Tuesday.

The chairman of the NRC, Gregory Jaczko, says all of the coolant has drained or evaporated from the No.4 pool, leaving the fuel rods fully exposed.  This is a prerequisite for a total meltdown of the fuel rods, in a reactor design that has been criticised for not being sufficiently robust to contain the consequences.

The temperature readings from de-activated reactors No.4, No.5 and No.6, for their spent fuel rod cooling pools, have been published by the International Atomic Energy Agency.  The cooling ponds are specified to remain at 25 degrees with continuous coolant level maintenance.  As of early this morning units 5 and 6 were also showing high and gradually rising readings.

Earlier today the director general of the International Atomic Energy Agency, Yukiya Amano, admitted that he didn’t know who he would be able to meet with when he arrives in Tokyo to learn more about the state of affairs at Fukushima Daiichi.

At the moment Tokyo Electric says it hopes to restore power to the water pumping system at the complex today.  It earlier abandoned attempts to drop water and boric acid on reactor 4.  There has been no further guidance on official disclosures of structural damage inside reactor 2.