Radioactivity

Radioactive contamination occurs when a radioactive product is deposited on an object or being or is ingested or inhaled. Contamination is distinct from irradiation, in which the object or being is subjected to ionising radiation.

In case of contamination, the object or being is in permanent contact with the radioactive source until it has been eliminated. In case of irradiation, simply isolate or move the object or being away from the radiation source which will reduce the effect of irradiation.

Due to the radioactive materials they contain or produce, nuclear power plants, industrial fuel production sites or nuclear waste treatment sites, certain research laboratories, hospitals using radioactive sources and certain industries are potential sources of contamination and irradiation.

REGULATIONS

The objective of nuclear safety is to protect people and the environment in all circumstances, by preventing the dispersion of radioactivity. At the beginning of the 1970s, the concept of “defence-in-depth” was established, with successive lines of defence being set up in power plants. These are based on material, organisational, and human measures designed to ensure optimum safety conditions.

Defence-in-depth comprises of five levels, which aim to prevent the occurrence and limit the consequences of failures likely to lead to incidents or accidents. These levels apply in the different states of facility, from normal operation (level 1) to core meltdown accidents leading to releases into the environment (level 5).

PROTECTION AGAINST RADIOLOGICAL HAZARDS

In the field of passive fire protection of basic nuclear installations (BNI), a radiological protection requirement is necessary to ensure the safety of equipment and the protection of people.

The required level of radiological attenuation is defined according to the radiological surveys on the premises concerned. For construction elements, such as joints, doors or penetrations, the requirement is generally an attenuation at least equal to that of the surrounding concrete. For temporary protection elements, such as radiation protection, the reference is generally attenuation of Gamma (γ) and Neutron (η) radiation.

The distribution of radiation types is a function of the emitting radiation source. Attenuation performance can be proven by two distinct methodologies:

• Either by an approved laboratory test,
• Or by a justification report issued by a qualified organisation.

Our products can be optimised and sized according to the specific radiations and/or risks of each BNI. These studies have been carried out for ITER, EDF and CEA.