1. General presentation

A nuclear reactor comprises :

• the fissile material (fuel) in which fission takes place;

• a light material (moderator) or, on the contrary, no light material; depending on whether or not one wants to favour fission by low (< 1 eV) or high (> 100 keV) energy neutrons;

• generally, fertile material (uranium or thorium) which is transformed into fissile material by the absorption of a neutron followed by the emission of one or more electrons;

• a heat transfer fluid that recovers the thermal energy produced by fission and transfers it to the end user in the form of heat or electricity;

• structural materials, which are used to position the various components and give the reactor its specific shape;

...