Guidance

Wales - Subregion 2

National Geological Screening for a GDF - Wales region

From:: Nuclear Waste Services
Published: 19 December 2018
Last updated: 16 January 2019 — See all updates

The screening report hosted on this site is a technical exercise across England, Wales and Northern Ireland. No specific location in England, Wales or Northern Ireland has been identified as a potential GDF site. Any future decision on geological disposal would be subject to community agreement and planning and environmental consents.

Details

Our work shows that we may find a suitable geological setting for a GDF in a small part of this subregion, although the thickness and properties of the potential host rocks present may not be suitable.

Rock cannot generally be seen at the surface in this subregion, except in man-made excavations such as quarries or road cuttings. However, deep boreholes and geophysical investigations, largely associated with mining, give us an understanding of the rocks present and their distribution.

There are various types of gaps in our understanding of geology and we deal with these gaps in a number of ways.

There are clay-rich rock layers to the east of Wrexham and rock salt layers to the west of Whitchurch in which we may be able to site a GDF. The available information suggests that they may be too thin and we would need to do more work to find out whether these rocks have suitable properties and thicknesses.

Even where individual clay-rich rock layers are found not to be thick enough to host a GDF they may support the siting of a GDF in deeper rocks as they could act as a barrier to groundwater flow from depth. This is important because movement of groundwater is one of the ways in which radioactive material could be carried back to the surface.

Some of the subregion has been mined to depths below 100m for coal resources in the Flint and Denbighshire portions of the North Wales Coalfield, and lead and zinc south of Holywell and west of Wrexham. In these areas the mining is likely to have affected the way in which water moves through the rock. Also possible exploration in the future in these areas means that it is more likely that future generations may disturb a facility.

Parts of the east of the subregion have Petroleum Exploration & Development Licences to allow companies to explore for oil and gas. This exploration is currently at an early stage and it is not known whether oil or gas in these licence areas will be exploited. RWM will continue to monitor how this exploration programme progresses.

Parts of this area, in the Dee Estuary and south of Buckley, are Coal Authority Licence Areas allowing companies to explore for coal. It is not known whether coal in these licence areas will be exploited. RWM will also continue to monitor how this exploration programme progresses.

For further information, read the report below.