Evolution of the discharge impact assessments in the French regulation framework
Chartier, M.; Despres, A.; Guillaume, R.; Plazanic, P.; Supervil, S.; Hubert, P.
IRPA-10: 10. international congress of the International Radiation Protection Association Hiroshima (Japan) 14-19 May 2000, P-4b-248.
The French regulation on discharge authorisation procedures has been modified in 1995. The French authorities are thus committed to re-examined the discharge authorisations for all French nuclear installations. A new examination of discharge authorisations is in progress. The authorisations to discharge liquid and gaseous effluents had been granted at the time of the development of the nuclear installations (power plants, laboratories, facilities) according to a procedure defined in 1976. The recommendations of the ICRP expressed in the publication n deg 60, endorsed for the main part of them by the 1996 European, modified the concept of <> for discharges, inter alia with an increased stress on optimisation. This evolution is consistent with the French low which does not recognise the right to pollute but defines a regime of authorisations which are always revocable. Consequently, the French authorities committed themselves to reductions of discharge limits as low as possible, at economically affordable cost. Since 1976, the evolutions of the principles of radiation protection for populations and of the French regulation together with the experience of 25 years of operations yielded significant changes of the approach of radiological impact assessments used in the regulation framework. This paper discuss and illustrate these changes: 1. Differences between the situation in 1976 (installations were planned) and now (most installations have operated since several years or tens of years) are first put forward: discharged activities, compositions of the effluents, variations of the discharges and their grounds are now better understood. Techniques to reduce discharges have been developed. The opportunities in terms of discharge reductions and accuracy of radiological impact assessment are underlined. 2. Main characteristics of the bases of the radiological impact assessments used in the French regulation framework are then described: identification of existing reference groups, realistic dose calculations (no more << envelope assessments>>), combination of impacts of liquid and gaseous discharges and possibly of direct shine from installation, combined analysis of the effects of chemical and radioactive discharges (possibly thermal discharges), taking into account uncertainties, demonstration of optimisation. The state of the art with respect to those various improvements is discussed together with differences with the previous approach of radiological impact assessments (dose envelope assessments, liquid and gaseous impact assessed separately, deterministic calculations, no optimisation demonstrations). 3. New evolutions wished by the experts of IRSN are sketched out: systematic a posteriori assessment of the doses due to real discharges, more quantitative approach of uncertainty, more formalised and quantitative approach of optimisation. 4. Eventually, the scope of discharge authorisations is discussed in connection with the definition of the << normal operation>> (as opposed to incidental/accidental situation).