Ydinpolttamista

Ydinpolttamista refers to the process of nuclear fission where a fissile atom, typically uranium-235 or plutonium-239, absorbs a neutron and splits into two or more lighter nuclei. This splitting releases a significant amount of energy in the form of heat and gamma radiation, as well as additional neutrons. These newly released neutrons can then go on to induce fission in other fissile atoms, creating a self-sustaining chain reaction.

The concept of nuclear fission was first experimentally demonstrated in 1938 by Otto Hahn and Fritz Strassmann, with theoretical explanation provided by Lise Meitner and Otto Frisch. The energy released during fission is harnessed in nuclear reactors to generate electricity. In these reactors, a controlled chain reaction is maintained by using materials that absorb excess neutrons, such as control rods made of cadmium or boron. The heat produced by fission is used to boil water, creating steam that drives turbines connected to generators.

Uncontrolled nuclear fission forms the basis of nuclear weapons. In a nuclear explosion, a rapid and exponentially growing chain reaction releases a massive amount of energy in a very short period. The fissile material must be assembled into a critical mass, where the rate of neutron production exceeds the rate of neutron loss, for a chain reaction to occur. The efficiency and yield of a nuclear weapon depend on factors such as the type and purity of the fissile material, the geometry of the assembly, and the effectiveness of the implosion mechanism (in some designs).