Fukushima I in undeniable meltdown

The information is piling up and all supports the idea that at least one of the reactors at Fukushima I is in unstoppable meltdown. Latest reports from Energy News:

• Report on neutron beams — Has a reactor at Fukushima gone “critical”?
• *ALERT* IAEA says Fukushima reactors may have achieved “re-criticality” — Increased radiation releases possible.
• IAEA: “Uncontrolled nuclear chain reactions” may be coming from melted fuel in No. 1 reactor.
• Radioactive iodine now at 4,385 times legal limit in water near Fukushima plant — “Radiation may be leaking continuously into sea”.
• “Very high levels of contamination” far away from Fukushima exclusion zone — More than double amount Soviets set for “relocation” at Chernobyl.

This is just from the last few hours but indications of meltdown were apparent earlier, I understand, just that played down.

Also a nearby reactor, Fukushima II, showed a smoke plume yesterday. Let's not forget that there are other three reactors that have got cooling problems.

Now the authorities may finally acknowledge that this is a Chernobyl-like situation that requires Chernobyl-like measures but there are serious unspoken difficulties.

The evacuation zone is ridiculously small: criminal negligence

The true danger zone around Fukushima I (legend here)

This has been an obvious issue: Japan has tried to avoid evacuating its citizens from a large area, even if that would be the rational thing to do. Already since day two or three, the USA suggested an evacuation zone of 80 km (50 miles), what is more than half the Fukushima prefecture, including the capital. However Tokyo has insisted in keeping the evacuation zone at the smallest size imaginable and, even when they decided to expand it, they did it only minimally. 

Dangerous levels of radiation have been detected at the latitude of Tokyo, by people and ships traveling to China, where radiation scanning is strict. This implies that all Northern Honshu is affected at levels that endanger human health to at least some extent and in ways pervasive enough as to be carried around the World through transport (i.e. it's not mere acute radiation but deposited, maybe inhaled, radioactive materials, where the true danger is). 

A 'Chernobyl solution' may not work

The Chernobyl solution consists in encasing the damaged reactors in a thick concrete sarcophagus. It is not a good solution but a lesser evil and surely needs persistent maintenance of some sort (a second sarcophagus to encase the original one is planned for Chernobyl but in wait of funding, design pictured at left).

The sarcophagus surrounds the reactor by five sides out of six. The sixth side, bottom, is Earth's ground. In the case of Chernobyl, well inland, this sixth side may not be a huge problem (though I am unsure of the details) but in the case of Fukushima and other seaside reactors it may be  big problem. 

Almost at sea level, Fukushima I surely sits on land that is continuously impregnated of water from the sea and/on underground channels flowing to the sea. One of the characteristics of a meltdown is that the magma-like radioactive core penetrates, by action of its corrosive nature and gravity, the bottom of the reactor and into the soil. 

While Tokyo may still decide to use the "Chernobyl solution" for lack of better ideas, I understand that there is clear risk that this solution is much worse for the circumstances of Fukushima I than for Chernobyl: continued radioactive filtration to the sea will not be possible to avoid most likely and that means that contaminated water will not just be spreading around the NE coasts of Japan (and beyond, how far?) but also that, via evaporation, some of that radiation will reach the atmosphere and keep haunting the region for centuries to come.