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Reference Number EP/R001499/1
Title Three Dimensional Optical Imaging of Neptunium Redox Speciation-A Feasibility Study
Status Completed
Energy Categories NUCLEAR FISSION and FUSION(Nuclear Fission, Nuclear supporting technologies) 100%;
Research Types Basic and strategic applied research 100%
Science and Technology Fields PHYSICAL SCIENCES AND MATHEMATICS (Chemistry) 80%;
ENVIRONMENTAL SCIENCES (Earth Systems and Environmental Sciences) 20%;
UKERC Cross Cutting Characterisation Not Cross-cutting 100%
Principal Investigator Dr LS Natrajan
No email address given
University of Manchester
Award Type Standard
Funding Source EPSRC
Start Date 01 July 2017
End Date 31 March 2019
Duration 21 months
Total Grant Value £196,048
Industrial Sectors Energy
Region North West
Programme Energy : Energy
Investigators Principal Investigator Dr LS Natrajan , Chemistry, University of Manchester (99.996%)
  Other Investigator Dr A Ward , Central Laser Facility (CLF), STFC (Science & Technology Facilities Council) (0.001%)
Professor SW Botchway , Central Laser Facility (CLF), STFC (Science & Technology Facilities Council) (0.001%)
Dr K (Katherine ) Morris , Earth, Atmospheric and Environmental Sciences, University of Manchester (0.001%)
Dr S Shaw , Earth, Atmospheric and Environmental Sciences, University of Manchester (0.001%)
  Industrial Collaborator Project Contact , National Nuclear Laboratory (0.000%)
Web Site
Abstract One of the most pressing problems facing society today is the management of existing and future waste forms arising from nuclear energy production. Here, the redox chemistry of the actinide elements plays a crucial role in many aspects of nuclear fission including safe disposal strategies and new recovery and recycling routes. Understanding the chemistry of actinides in engineered environments is imperative for the management of existing and future fission products (nuclear waste) arising from nuclear power production, particularly for underground geological disposal. In particular, the redox chemistry of neptunium, a key radionuclide found in appreciable quantities in high level waste is complex, changeable and currently not well understood.Over the lifespan of the proposed geological disposal facility, one of the principal hazards is a change in chemistry of neptunium that may result in leaching from the repository, breaching primary containment and entering the engineered environment. Due to the particular complex redox and chemical speciation of neptunium, crucial mechanistic information on redox chemistry and speciation that affects its interactions with engineered and natural encapsulating materials including the host rock and backfill material is lacking and remains one of the principal chemical challenges facing this field. In this feasibility study, we will address the prospect of using one and two photon fluorescence and phosphorescence spectroscopy and microscopy as a non-destructive technique to address this problem. We aim to visualise, locate and spatially map the different oxidation states of neptunyl that can co-exist in solution in model conditions using well defined complexes and aqua ions in with the ubiquitous geologically relevant minerals silica, alumina and calcite at previously unseen levels of detail (sub micrometer resolution). We have recently demonstrated that neptunyl(V) and (VI) emission occurs in the green and blue regions of the electromagnetic spectrum and are equally as intense as the uranyl(VI) ion, whose optical properties are well known and have been used by us for fluorescence and phosphorescence microscopy imaging. This means that both oxidation states can be detected simultaneously so that highly sensitive, informative three-dimensional imaging can be used to understand neptunyl geochemistry below the micron scale. This will add much needed important information to the safety case for nuclear waste disposal in a range of heterogeneous systems.
Publications (none)
Final Report (none)
Added to Database 21/02/19