Nuclear Radiation
Nuclear radiation is a combination of Alpha, Beta and Gamma particles.
The first particle found was the Alpha particle. This also happens to be the heaviest out of the three. This particle is the breakdown of heavier elements, such as Plutonium and Uranium. The Alpha particle is composed of two neutrons and two protons. When the Alpha particle is ejected it doesn't go very far. Your own bare skin will be able to prevent any danger from these particles. However if these particles are inhaled, or enter your body in any other way, they can cause damage. These particles are able to mutate or destroy the organs inside your body.

This
is used to indicate radioactive material.
The Beta particles are up to 8,000 times smaller than the Alpha particles. These particles are electrons produced by the nucleus of isotopes. These electrons produce energy that can damage you. Due to its size, the Beta particle can penetrate farther into people, animals, plants etc. Anytime a Beta particle interacts with a cell, it will tamper and eventually mutate a cell's nucleus. These mutations have been known to be passed onto generations after generations. However, the Alpha and Beta particles are harmless compared to the Gamma particles.
The Gamma rays, or particles, are in the same clan as x-rays and light. However, Gamma rays are far more powerful. These particles will destroy living cells as they pass through and object. It is powerful enough to go through walls. Only very concrete structures can stand against Gamma rays. These rays are also very capable of moving great distances. This will prove to be a powerful section of a nuclear bomb.

Examples of Alphe, Beta, and Gamma
radiation