Senior officials advise that there has been ‘no significant worsening’ and other such statements to that effect.  This type of statements always ring alarm bells for me.  Questions such as no significant worsening from what spring to mind and how bad was it to start with?

MSBNC report on the current crisis:

Emergency workers seemed to try everything they could think of Thursday to douse one of Japan’s dangerously overheated nuclear reactors: helicopters, heavy-duty fire trucks, even water cannons normally used to quell rioters. But they couldn’t be sure any of it was easing the peril at the tsunami-ravaged facility.

Three reactors have had at least partial meltdowns, but an even greater danger has emerged. Japanese and U.S. concerns were increasingly focusing on the pools used to store spent nuclear fuel: Some of the pools are dry or nearly empty and the rods could heat up and spew radiation.

It could take days and “possibly weeks” to get the complex under control, U.S. Nuclear Regulatory Commission Chairman Gregory Jazcko said. He defended the U.S. decision to recommend a 50-mile evacuation zone for its citizens, a much stronger measure than Japan has taken.

A senior official with the U.N.’s nuclear safety agency said there had been “no significant worsening” at the Fukushima Dai-ichi nuclear plant but that the situation remained “very serious.” Graham Andrew told reporters in Vienna that nuclear fuel rods in two reactors were only about half covered with water, and in a third they were also not completely submerged.

If the fuel is not fully covered, rising temperatures and pressure will increase the chances of complete meltdowns that would release much larger amounts of radioactive material than the failing plant has emitted so far.

Low levels of radiation have been detected well beyond Tokyo, which is 140 miles (220 kilometers) south of the plant, but hazardous levels have been limited to the plant itself. Still, the crisis triggered by last week’s earthquake and tsunami has forced thousands to evacuate and drained Tokyo’s normally vibrant streets of life, its residents either leaving town or holing up in their homes.

Physicist Michio Kaku tells msnbc’s Richard Liu that cooling attempts like using helicopter drops to cool down the 700 tons of spent fuel at Japan’s Fukushima reactor site won’t be enough, that they would be better served with a ‘Chernobyl’ approach.

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