Due to the Great East Japan Earthquake and tsunami of March 2011, the power supply was cut off, and it caused a major radiation leak at the Fukushima No.1 nuclear power plant. A nuclear power plant uses the energy released in the nuclear fission of uranium-235 absorbing neutron. The nuclear energy derived from the fission of 1 g of uranium is three millions times the energy compared with the fossil fuel energy such as oil. The reason why most countries rely on the nuclear energy is because its power generation efficiency is high and there is a concern over fossil energy procurement and depletion in the future. But nuclear fission produces unstable radioactive materials such as iodine-131 and cesium-137. Even though we could prevent a fission chain reaction over the critical point, we have to deal with radioactive materials with a long half-life over the coming decades.