RWM has updated its inventory for geological disposal (IGD) to take account of the 2016 UK Radioactive Waste Inventory (UK RWI).
The UK has been producing Radioactive Waste Inventories for over 30 years. The production process has been improved iteratively and is now well-established.
The IGD is drawn from the UKRWI, which is periodically published by the Government and NDA as an inventory of all radioactive waste in the UK. The last version of the UK RWI was published in 2017. Only a small proportion of the waste reported in the UK RWI (less than 10% by volume) is designated for geological disposal.
The 2016 IGD comprises four reports:
• the Main report describes the principal features of the 2016 IGD
• the Method report describes how IGDs are developed and updated
• the Differences report sets out the differences between the 2016 IGD and the previous version (the 2013 Derived Inventory). Uncertainty in the IGD is explored through the consideration of a number of alternative scenarios. The impact of the changes to the inventory on these scenarios has also been evaluated
• the Implications report describes the implications of the 2016 IGD for the generic DSSC
The inventory changes are small and the implications of these changes are:
• no impact on RWM’s Disposal System Specification as the scope of the inventory has not changed
• small changes to RWM’s illustrative generic Geological Disposal Facility (GDF) designs
- changes of -1% to +1% to the GDF footprint (host rock dependent)
- slight changes to the operational programme
• no change to the conclusions of RWM’s generic Transport Safety Case, as the number of disposal units is very similar and there are no significant changes to the activities
• no change to the conclusions of RWM’s Operational Safety Case, which is based on bounding source terms that are unaffected by the inventory changes
• no change to the conclusions of RWM’s generic Environmental Safety Case as the changes to the inventory are small
• no change to the Disposability Assessment process, as there are no significant changes to the findings of the generic DSSC
Overall, the inventory changes do not affect the conclusions of RWM’s 2016 generic DSSC.
A key objective of the work described in this report was to identify any new research needs arising as a result of the changes to the IGD. No new research needs were identified. However, the scope of existing tasks has been extended to cover the inclusion of UK Advanced Boiling Water Reactor (ABWR) spent fuel in the areas of criticality safety and spent fuel dissolution.
Much of the analysis and information we publish is based on certain planning assumptions, and is often subject to caveats. In providing the latest information on materials designated for geological disposal, it is important to ensure consistency in the way in which the data is presented. It would not be appropriate to simply extrapolate data by, for instance, making different assumptions, e.g. for different new nuclear build scenarios.