After several explosions at the Fukushima I nuclear plant, Asian countries are being alerted as Japanese officials say that "the nuclear fuel rods appear to be melting." The situation has intensified the debate on nuclear power in many countries while the Japanese and the nearby people are preparing themselves for the worst case scenario.
The best case study available as to what the implications of a fallout is the Chernobyl incident. When the core of the nuclear plant at Chernobyl melted as a result of human and instrumental errors, the fallout affected many states. Much affected was the Soviet Socialist Republic of Belarus in the Soviet Union.
While Uranium and especially Plutonium are dangerous nuclear fuel, more dangerous are the fission products of the fuel. Radioactive isotopes of iodine and strontium are dangerous because they can accumulate in food chains. Gaseous isotopes and very small particles can be dispersed by air. In Chernobyl, radioactive isotopes of noble gases were released to the atmosphere immediately.
Exposure to dangerous levels of radiation will give rise to Acute Radiation Sickness. In an accident in a nuclear plant, this is mainly possible in the people in the vicinity of the accident. Residual radioactivity arises through the accumulation of radiation in groundwater, fish etc. Its impact may be seen after several months or years. It depends on the half lives of the isotopes.
It is feared that Japan will be the victim of yet another disaster after the devastating Tsunami.