Nuclear barrels

Solving an old problem with new solutions

Nuclear Waste Services (NWS) has successfully sealed existing boreholes at Rosemanowes Quarry in Cornwall, as part of a research project for the safe and permanent disposal of higher activity radioactive waste. 

As part of the search for a suitable site for a geological Disposal Facility (GDF) in the UK, NWS has begun a USD $6 million project to investigate and demonstrate its approach for deep borehole sealing. 

A GDF comprises of a network of highly engineered underground vaults and tunnels built to permanently dispose of higher activity radioactive waste so that no harmful levels of radiation ever reach the surface environment. Countries such as Finland, Sweden, France, Canada and the USA are also pursuing this option.

During August and September 2022, the latest phase to find a suitable site was carried out at the Borehole Test Facility at the Rosemanowes quarry. NWS said the site, formerly a working quarry, offers access to one of the most comprehensively mapped well systems in the world.

Two pre-existing boreholes in granite – one two kilometres deep and the other 300 metres deep – were successfully sealed using new technology called a Downhole Placement System (DPS) tool.

Bentonite clay was used as sealant because of its low permeability and swelling properties, with cement being used for seal support. 

Commonly found world-wide and used in international waste management programmes, bentonite will also be packed around some GDF waste packages as part of the engineered barrier system that will isolate and contain disposed waste in the UK GDF.

The results demonstrated that the bentonite could be released by the DPS into a borehole at a depth of two kilometres.

Simon Norris, Principal Research Manager at NWS and Project Technical Lead said, “we wanted to show that we have the necessary toolkit of approaches, procedures, and equipment to seal any boreholes we may construct in the GDF siting process, and this research was a step closer to achieving this goal.”

The DPS tool is currently being tested in different locations with varying rock types and at varying borehole depths.

Like articles on nuclear topics? Check out last month’s piece on Nuclear Density Gauges.