The British Nuclear Fuels Drigg low-level waste site characterization programme

Abstract

Abstract Site characterization work is being undertaken to underpin the post-closure radiological assessment of the UK’s Drigg low-level radioactive waste disposal site. This work is providing high-quality data on the geology, hydrology and hydrogeology of the site, thus ensuring that both the monitoring programme and predictions of the radiological impact are based on a good understanding of the hydrogeology. The programme has two phases. The first addresses the surface water balance of the site; this has been achieved by constructing a surface water balance model which has been combined with a forest interception model to determine the hydrologically effective rainfall. This model has been calibrated using extensive soil moisture data gathered on-site. The second phase is concerned with improving knowledge of the site geology and hydrogeology. Continuously cored rotary boreholes are being drilled across the site to recover geological data. Additionally, a complementary geophysical programme and trial trench studies have been undertaken. Hydrogeological data are being provided by a series of borehole clusters, drilled using cable percussion rigs, centred around the rotary boreholes. During the drilling of the cable percussion boreholes, extensive hydrogeological and hydrogeochemical data are being acquired. These data, in conjunction with data from weirs on the site streams, will provide the data required to complete the hydrogeological water balance.