The long-term evolution of candidate Pu wasteforms as a function of groundwater composition

Lead Research Organisation: University of Sheffield
Department Name: Materials Science and Engineering

Abstract

Research and development is currently being undertaken to underpin a Nuclear Decommissioning Authority recommendation to Government in 2025 regarding the preferred re-use / disposal option for the UK's civil stockpile of separated plutonium. This research, part-funded by Radioactive Waste Management Limited, aims to build underpinning science for the decision about which disposal option is preferred for the part of the plutonium inventory that cannot be re-used, or the whole inventory, if plutonium is declared a waste in the future.

This PhD project aims to quantify the dissolution kinetics and mechanisms of two candidate Pu-wasteform materials - disposal MOX [(U,Pu)O2] and zirconolite ceramics (e.g. CaZr0.8Ce0.2Ti2O7) - as a function of varying groundwater composition. The project will use batch, flow-through and surface-sensitive techniques to rapidly (within days to months), and precisely, quantify the effect of pH, Eh and ionic strength on the dissolution rates of Pu surrogates (Th and Ce), U and neutron poisons (e.g. Gd, Hf). Dissolution in synthetic groundwater solutions, backfill pore water, under oxic and anoxic conditions, will also be investigated using these techniques.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/S022295/1 01/04/2019 30/09/2027
2570862 Studentship EP/S022295/1 21/09/2020 30/09/2024 Ismail Aldean