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Radiological protection

Radiological protection, or radiation protection, encompasses all measures taken to protect people and their environment by preventing or reducing the harmful effects of the ionizing radiation to which they might be exposed, either directly or indirectly.
Radioelements, i.e. atoms with radioactive nuclei, emit radiation that interacts with other matter, possibly ionizing it by removing one or more electrons from its atoms. This is called ionizing radiation.
Ionizing radiation has two types of effects on human health:
- Short-term (or deterministic) effects such as temporary masculine sterility, burns, tissue necrosis, nausea or fatigue;
- Long-term (or stochastic) effects such as cancer and genetic anomalies.
The tissues that are most vulnerable to radiation are the reproductive tissues, those involved in blood cell formation, the skin and the lens of the eye.

The three basic principles of radiological protection, related to the source and regardless of the circumstances of exposure, are:
- Justification: techniques involving ionizing radiation must not be used if there are alternative solutions, unless the benefit to society outweighs the risk;
- Optimization, or what is called the ALARA (“as low as reasonably achievable”) principle: keeping exposure to ionizing radiation to a minimum;
- Dose limitation: legally-defined maximum radiation thresholds per person per year.
There are three main sources of exposure: natural, professional / medical, and environmental due to current or past human activity involving ionizing radiation.
- Natural radioactivity can cause external exposure due to telluric or cosmic radiation, or internal exposure due to radioactive elements in food, drinking water, or the air we breathe (radon gas). In both cases, the radiation is absorbed by the body. The intensity of natural radiation varies from one geographic area to another. In France it averages 2.4 mSv per person per year.
- The medical sector (radiation therapy, radiology), the nuclear industry, research laboratories and many industrial sectors (food preservation, X-ray inspection) use ionizing radiation. The level of exposure is determined by a number of factors, including the type of radiation, the distance from the source, the duration of exposure, the thickness and material of the protective barriers, as well as the possible presence of dynamic confinement systems. The worksites are subjected to regular technical inspections and to measurements of the radiation doses received by the personnel. Operational dosimetry, which measures external exposure in real time, became mandatory in France in 2000 for all personnel working in a controlled zone. It supplements passive dosimetry (with delayed readout), which has been required for all types of restricted zones for the past 30 years. Internal exposure is assessed by measuring isotope levels in urine, feces and secretion samples, or by anthropogammametry (whole body counting). For workers exposed to radiation, the total effective dose, the sum of external and internal exposure, is limited to 20 mSv per year. For the rest of the population, the maximum dose is 1 mSv per year, excluding medical, natural and environmental exposure.
-Environmental exposure associated with human activity primarily concerns the environmental impact of the nuclear industry. In France, it is subject to radiological monitoring by the National Network for the Measurement of Environmental Radioactivity (RMN)). This multidisciplinary network was set up in 2003 in order to respond to societal concerns about nuclear power.