ICRP
For many decades now, the International Commission on Radiological Protection (ICRP) has been publishing radiation protection recommendations which are usually adopted as the basis for international standards (particularly those issued by the IAEA) and community directives. New recommendations are currently being prepared. After consultation concerning an initial draft in 2004 on its website (www.icpr.org), new proposals were made in 2005 for a publication planned for 2007, following a further consultation. These recommendations will be issued together with fundamental documents concerning the biological and epidemiological bases for risk assessment, the values and units used in radiation protection, characterisation of the reference individual for dose estimates, optimisation of radiation protection and protection of the environment.

Thus an estimate of the number of cancers attributable to exposure to ionising radiation can be calculated, using a linear extrapolation without threshold of the relationship observed at high doses. The legitimacy of these estimates however remains open to debate within the scientific community.

In this context, and on the basis of the scientific work performed by UNSCEAR (see box), the International Commission on Radiological Protection (see ICRP publication 60) published coefficients for the risk of death by cancer due to ionising radiation, identifying a 4% excess risk per sievert for workers and 5% per sievert for the population at large. Use of this model, for example, would lead to an estimate of about 7000 deaths in France every year, as a result of cancer due to natural radiation.

Evaluation of the risk of lung cancer due to radon is the subject of a specific model, based on observation of epidemiological data concerning mine workers. Assuming a linear relationship without threshold for low-dose exposure, the relative risk linked to radon exposure, for a radon concentration of 230 Bq/m3, would be about the same as passive smoking (USA Academy of Science, 1999).

The health goal of reducing the risk of cancer linked to ionising radiation cannot be directly observed through epidemiology; the risk can be calculated if we assume the existence of a linear relationship without threshold between exposure and the risk of death from cancer.
  1.3 Scientific uncertainty and vigilance
The action taken in the fields of nuclear safety and radiation protection in order to prevent accidents and limit detrimental effects has led to a reduction in risks but has not reached either zero risk nor zero impact, whether in terms of the doses received by medical or industrial workers, or those associated with releases from BNIs. However, many uncertainties and unknown factors persist and require the ASN to remain attentive to the results of the scientific work in progress, for example in radiobiology and radiopathology, with possible spin-offs for radiation protection, particularly with regard to management of risks at low doses.