Nuclear Energy

Einstein's energy/mass formula. (E=mc2)

Fission: the splitting of large nuclei such as Uranium or Plutonium into smaller pieces with the release of considerable energy (equivalent to a mass lose by Einstein's formula). For example:

235U92 + 1n 144Ba56 + 89Kr36 + 3n +E

Critical mass: the mass of a substance (which is also dependent upon the geometry and other physical factors) necessary to sustain a nuclear explosion.

Control rods: rods which can be inserted in a reactor core to modulate the speed of the atomic fission reaction by absorption of neutrons. They are made of materials that tend to absorb neutrons such as graphite (carbon) and cadmium.

Fussion: the combining of atomic nuclei into larger pieces with the release of energy. This is the type of process that powers the sun. In the solar interior, 4H nuclei combine (through a step by step process) to form a single He nucleus. This requires a temperature of tens of millions of degrees C.
A possible reaction for a future fusion reactor is the following in which deuterium and tritium are combined to form energy:

2H1 + 3H14He2 + 1n + Energy

Binding energy: The energy that atomic nuclei need to hold themselves together. You can only get usable nuclear energy by changing nuclei from high binding energy to nuclei of lower binding energy. Iron is the nucleus with the minimum binding energy. Atomic nuclei with atomic numbers greater than iron require energy to form. They are formed in star, in particular in nova and supernova events.


Radioactive products.