Evaluation of the initial and final radiological status of a nuclear facility in sanitation status

This technical report is a guideline for radiological assessment of a nuclear facility in remediation stages. From initial state of remediation to final status survey it describes the best suited statistical or geostatistical approach for the characterization of sites contaminated by radionuclides. Prior to any characterization campaign an historical analysis coupled with a function analysis targeted investigations is fundamental to obtain a robust overview. The evaluation of the amount of radioactive material present in a defined area requires a sampling strategy correlated with characterization objective. On the other hand correlation between remediation objectives and characterization objectives also requires knowing acceptable level of risk. This give better inputs to allow available resources and take into account environmental constraints. In particular, radiological characterization of infrastructures is one of the key step to conduct industrial project of decommissioning nuclear facilities in remediation. It needs a reliable initial diagnosis to obtain an efficient waste management with a financial control Optimization of the production of nuclear waste. It is an important part of Setting the Off Final - Dismantling). This approach is compatible with French Regulation (Guide 14 ASN) for the first and second line of defence. Annexes provide feedback of experimentation of this methodology. This report supplements the methodological guide published by the GT10 CETAMA entitled 'Soil Radiological Characterisation Methodology' (CEA-R 6386). The latter is intended for project managers and covers all issues related to the characterization projects for soil. This guideline concern specifically design engineers in charge of implementation program at the different stages of investigation and data processing. Similarly, the proposed methodology can be broken for the characterization of chemical pollution and process equipment. (authors)