The paper considers health risk of Japanese population and neighboring countries being the consequence of the major accident (level 7 on INES scale) in Fukushima Dai-ichi I nuclear power station. On March 11 an earthquake of magnitude 9 on Richter scale, off the Pacific coast of the Japanese main land, caused a massive tsunami that crippled the cooling systems at the nuclear plant. That led to reactor meltdowns, hydrogen explosions, and major release of radioactive material into the air. To enable a better understanding of the different and severe consequences of the accident, the article describes the physical background of functioning of nuclear reactors, the hypothetical reasons of damages and interference of their operations, the mechanism of mreleasing radioactive pollutants into the atmosphere and the consequences for the population living in the area, on which radioactive fallout is observed The accident in Fukushima is remarkable because for the first time considerable amounts of plutonium isotope 239Pu were released into the environment. The author presents his negative opinion concerning the prospect that nuclear power stations will be 100% failure-free and will be totally safe for human population. The Fukushima nuclear disaster is the third major accident known in the history of nuclear power plants caused or enabled by man. Attention is also paid to phenomenon of lobbing pro existence and development of nuclear power. It is motivated by selfish corporation interest in which representatives of scientific community, industrial corporations and military bodies play a significant role.