RWM703 - Site Characterisation Interpretation Support

RWM (NWS) is a wholly owned subsidiary of the Nuclear Decommissioning Authority ("NDA") and is the body responsible for implementing geological disposal of higher activity radioactive wastes. Government policy has confirmed that RWM will act as the developer of a Geological Disposal Facility (GDF) for such wastes. As such, RWM is responsible for ensuring that the siting, construction, operation and eventual closure of a GDF are carried out in a manner which adheres to, and complies with, the UK's high standards of safety, security and environmental protection, as well as applicable requirements which are set out in relevant policy documentation.

RWM has identified Search Areas with adjacent inshore areas (offshore up to the 12 nautical mile UK territorial limit) to be investigated. The geological understanding of each area is different and is determined by the complexity of the geological setting, the amount of previously published information and the quantity and quality of legacy data (historic oil and gas seismic and well data, mining boreholes etc).

RWM are in the process of instigating Contract, RWM169 (Site Evaluation, Lot 2, underway) which is tasked with producing an initial understanding of the search areas, based on accessible public datasets (for example held by BGS or published in peer reviewed journals) and the outcomes of previous studies (such as NIREX). RWM also is undertaking a first look analysis of legacy oil and gas data, carried out under Contract RWM400 (Site Characterisation, underway). The output from these two works will be delivered as a series of databases, reports and an overarching synthesis report to this Contractor.

The next stage of work is this Site Characterisation Interpretation work package, which will enable RWM to move from the initial general understanding gained from the work carried out under RWM169 and RWM400, described above, to a more integrated site-specific understanding. This requires the evaluation of additional legacy data and new seismic data sets, being acquired by RWM. These additional data include further legacy 2D and 3D seismic and borehole data for all search areas, plus newly acquired seismic data, starting with a 250 km2 3D seismic volume for offshore Copeland (acquired by RWM in August 2022). Further seismic campaigns are being considered for other search areas.

The focus of this Site Characterisation Interpretation work will be on developing a fully integrated and detailed understanding of the potential GDF host rock volume for each site. This will include an evaluation of its geometries, including structural and stratigraphic variations, based on detailed analysis of the regional, sub-regional and site-specific sub surface.