A CONTAMINATED LAND APPRAISAL OF AN OPERATING NUCLEAR LICENSED SITE

Key words: characterisation, decommissioning, groundwater, heterogeneity, management, prevention, radionuclides, remediation, risk assessment, sam- pling programme, site investigation, soil, soil gas

Nuclear licensed sites are generally environmentally complex. Invariably there has been a long and varied industrial site history prior to nuclear operation. The potential for the presence of historically sourced and diverse contamination is, therefore, greatly increased. For those nuclear licensed sites that are still in operation and may not be decommissioned for many years to come the charac- terisation of contamination issues may be hampered by existing structures and processes still in operation, yet there may be shorter term drivers to undertake such work. A heterogeneous geological and complex hydrogeological setting can present complications to the characterisation process in their own right but these complications may be exacerbated if combined with other factors such as varied historical industrial site usage and current operations. Clear goals, there- fore need to be established and the interactions between the geological and hydrogeological processes operating locally to the site need to be understood. To ensure that all goals are met characterisation work needs to be undertaken in a well co-ordinated and cost effective manner. On many nuclear sites the ma- jority of site investigation work previously undertaken has been focused on the acquisition of geotechnical and health physics data in support of decommis- sioning and construction activities. Data sets specifically required for contami- nated land appraisal have, therefore, not been systematically established. The limited nature of key data sets can offer only tentative direction to future con- taminated land appraisal. Through the utilisation of a Value Engineering Study it should be possible to capture all the drivers and objectives that a site wide investigation should underpin. These include the following, most of which are inextricably linked: