Methodological guide for risk assessment and management of industrial sites contaminated with radionuclides
A. Oudiz, J. Brenot, B. Cessac, P. Charbonneau, J.P. Maigné, P. Santucci
IRPA-10: 10. international congress of the International Radiation Protection Association Hiroshima (Japan) 14-19 May 2000, P5-318
France has known about the existence of industrial sites contaminated with long-lived radionuclides such as radium for a long time and the clean-up of the first sites dates back to the 1960s.
In the mid 1990s, the authorities responded to the needs of the operators responsible for the clean-up of sites by establishing operational objectives for the decontamination of soil and buildings on a case-by-case basis. Thus, for example, for certain sites contaminated with radium-226, the decontamination objectives are as follows (1):
- Outdoor, the levels for hot points are 5 Bq/g of soil and 1 ì Gy per hour;
- Indoor, the levels are 1 Bq/g of material and 0.2 ì Gy per hour;
- For all surfaces with a non-fixed contamination, the level is 1 Bq/cm 3 of material collected (sampling of 10 cm by 10 cm by 0.1 mm).
These levels are based on the hypothesis of 1000 hours spent outside per year and 5000 hours spent inside per year. They were established to satisfy implicitly an equivalent dose of some tenths of a mSv per year, barring an exceptional case (someone staying permanently in the immediate vicinity of the hot points). Such levels were effectively applied for the remediation of certain sites.
The current regulatory framework for the management of sites contaminated with radionuclides may change with the transposition into French law of the European directive on Basic Safety Standards (96/29) of May 1996. The authorities assigned the task of preparing a guide for industrial sites potentially contaminated with radioactive substances 1 to the Nuclear Safety and Protection Institute. Similar guides had been already drafted for sites polluted by chemical substances in France. They covered the initial diagnosis, the simplified risk study (1995, revised in 1997) (2) and the detailed risk study (to be published in 2000).
For the sake of consistency, the authorities requested that our guide be based, as far as possible, on the approach adopted for sites polluted by chemicals. The guide completed by the end of February 2000 will be made public once it has been approved by the two ministries (Health and Environment) that commissioned it. The aim of the guide is to provide an operational framework for the management of radioactively contaminated sites, which will replace the current case-by-case approach by a set of recognized procedures that will ensure the "traceability" of the whole process from assessment to decision. It will provide a system of reference for all the stakeholders involved and will permit dialogue on a common basis.
1 Sites at which industrial activity or research involving radioactive substances was carried out in the past. The sites of nuclear facilities in operation or in the process of decommissioning are excluded from the scope of the guide.