Stainless steels are non-combustible and have good temperature behaviour, with a melting point higher than 1,420°C, giving them a major advantage over lead.
The most common grades are austenitic stainless steels 304L (Z2 CN18-10) and 316L (Z2 CND17-12).
For fasteners, the common names are A2 and A4 stainless steel (A2 for grade 304L, A4 for grade 316L).
Used for welding and machining, stainless steels are ideal for making shielding screens such as stationary or moving mechanical parts.
They are often used for containment walls in contact with the radioactive source.
Stainless steels have excellent resistance to gamma radiation.
However, under neutron flux, they produce capture gamma rays, with energies between 1 and 10 MeV, and activate at highly variable levels depending on the level of impurities (presence of Mn, CO, Ti, etc.).
Under very high neutron flux, the transition temperature (brittle fracture / ductile fracture) also increases.