Radioactive Waste Management Limited (RWM), trading as Nuclear Waste Services (NWS), has recently published the Guide to reference groundwater and porewater compositions. This report has been prepared by British Geological Survey (BGS) in collaboration with Quintessa, as an output for the project RWM543 “Reference Groundwaters”.
This guide provides a summary of available data and information relating to chemical compositions of groundwaters and porewaters within a defined group of Lower-Strength Sedimentary Rocks (LSSRs) across England. This includes the Kimmeridge Clay Formation, Oxford Clay Formation and Mercia Mudstone Group.
The available data has been collated as a first step towards the production of a set of ‘reference’ chemical compositions of water typical in these LSSRs. These are intended to encompass the compositional ranges likely to be encountered in a Geological Disposal Facility (GDF) during the construction, operation and post-closure periods.
Quintessa’s role in delivering the guide was to provide project management and technical steer in defining credible and internally consistent chemical compositions of groundwaters and porewaters that could occur in a specified LSSR formation under given environmental and hydrogeological conditions. This involved the use of water analyses for the rock formations of interest and data for analogous formations provided by BGS, and geochemical modelling.
Quintessa’s participation in the project built on our existing expertise and knowledge in deep geological disposal and quantitative geoscientific consulting.