A5022957234- Radioactive element chemistry and processing
- Radioactive contamination and transfer
- Nuclear materials and radiation effects
- Nuclear Materials and Properties
- Radioactivity and Radon Measurements
- Nuclear Physics and Applications
- Nuclear and radioactivity studies
- Mercury impact and mitigation studies
- Chemical Synthesis and Characterization
- Graphite, nuclear technology, radiation studies
- International Law and Aviation
- Optics and Image Analysis
- Geological and Geochemical Analysis
- Conflict of Laws and Jurisdiction
- Geochemistry and Geologic Mapping
- Advanced Electron Microscopy Techniques and Applications
- Coal and Its By-products
- Advanced X-ray Imaging Techniques
- Radiation Shielding Materials Analysis
- Ion-surface interactions and analysis
- 3D Modeling in Geospatial Applications
- X-ray Diffraction in Crystallography
- Geophysical Methods and Applications
- Selenium in Biological Systems
- Laser-induced spectroscopy and plasma
University of Helsinki
2019-2022
University of Manchester
2014-2022
University of Cumbria
2014-2019
National Nuclear Laboratory
2016
University of Huddersfield
1912
Highly radioactive cesium-rich microparticles (CsMPs) were released from the Fukushima Daiichi nuclear power plant (FDNPP) to surrounding environment at an early stage of disaster in March 2011; however, quantity CsMPs remains undetermined. Here, we report a novel method quantify number surface soils or around and fraction radioactivity they contribute, which call "quantification CsMPs" (QCP) is based on autoradiography. photostimulated luminescence (PSL) linearly correlated various...
Understanding the long-term fate, stability, and bioavailability of uranium (U) in environment is important for management nuclear legacy sites radioactive wastes. Analysis U behavior at natural analogue permits evaluation biogeochemistry under conditions more representative equilibrium. Here, we have used bulk geochemical microbial community analysis soils, coupled with X-ray absorption spectroscopy μ-focus fluorescence mapping, to gain a mechanistic understanding fate transported into an...
Argillaceous rocks, such as Opalinus Clay, are considered potential hosts for high-level radioactive waste repositories due to their low permeability and ability retard radionuclide migration. In these formations, diffusion is the primary transport mechanism radionuclides. Previous laboratory studies have indicated that effective coefficients non- or weakly-sorbing radionuclides increase exponentially with temperature between 0 70°C, suggesting higher temperatures could enhance...
Laser Induced Breakdown Spectroscopy (LIBS) has the potential to allow direct, standoff measurement of contaminants on nuclear plant. Here, LIBS is evaluated as an analytical tool for Sr and Cs contamination type 304 stainless steel surfaces. Samples were reacted in model acidic (PUREX reprocessing) alkaline (spent fuel ponds) bearing liquors, with multi-pulse ablation also explored measure contaminant penetration. The II (407.77nm) I (894.35nm) emission lines could be separated from bulk...
Metaschoepite is commonly found in U-contaminated environments and metaschoepite-bearing wastes may be managed via shallow or deep disposal. Understanding metaschoepite dissolution tracking the fate of any liberated U thus important. Here, discrete horizons (UO3·nH2O) particles were emplaced flowing sediment/groundwater columns representative UK Sellafield Ltd. site. The column systems either remained oxic became anoxic due to electron donor additions, sacrificed after 6- 12-months for...
Stainless steel coupons have been exposed to uranium-containing nitric acid solutions, in conditions similar those found various uranium handling nuclear facilities across the fuel cycle. Solid state analysis of stainless samples and solution composition were undertaken gain a better understanding contamination process mechanisms. immersed 12 M HNO3 containing (1 g/L), form uranyl, for periods up 255 days. Uranium was observed all time lengths exposure. Solution indicated that levels reached...
Analysis of a radioactive, coated concrete core from the decommissioned, spent nuclear fuel cooling pond at Hunterston-A site (UK) has provided unique opportunity to study radionuclides within real-world system. The core, obtained dividing wall and sampled fill level pond, exhibited radioactivity (dominantly (137)Cs (90)Sr) heterogeneously distributed across both painted faces. Chemical analysis was undertaken using microfocus spectroscopy Diamond Light Source, UK. Mapping Sr surface...
The Collaborative Materials Exercise (CMX) is organized by the Nuclear Forensics International Technical Working Group, with aim of advancing analytical capabilities participating organizations and providing feedback on best approaches to a nuclear forensic investigation. Here, model fuel materials from 5th CMX iteration were analyzed using NanoSIMS 50L (CAMECA) in order examine inhomogeneities 235U/238U ratio trace element abundance within individual, micrometer scale particles. Two pellets...
Abstract A detailed understanding of the response mineral phases to radiation fields experienced in a geological disposal facility (GDF) is currently poorly constrained. Prolongued ion irradiation has potential affect both physical integrity and oxidation state materials therefore may alter structure's ability react with radionuclides. Radiohalos (spheres damage minerals surrounding radioactive (α-emitting) inclusions) provide useful analogues for studying long term α-particle accumulation....
A critical radiation damage assessment of the materials that will be present in a Geological Disposal Facility (GDF) for radioactive waste is priority building safety case. Detailed analysis effects high-energy α-particle phyllosilicates such as mica necessity, these are model structures both clay-based backfill material and highly sorbent components crystalline host rock. The α-radiation stability biotite [general formula: K(Mg, Fe)3(Al, Si3O10)(F, OH)2] has been investigated using 5 MV...
Selenium (Se) is a toxic contaminant with multiple anthropogenic sources, including 79Se from nuclear fission. Se mobility in the geosphere generally governed by its oxidation state, therefore understanding speciation under variable redox conditions important for safe management of contaminated sites. Here, we investigate behavior sediment groundwater column systems. Experiments were conducted environmentally relevant concentrations, using range compositions, and impact electron-donor (i.e.,...
The complex, nanometer-scale structural changes resulting from long-term α-particle bombardment of the mineral biotite are revealed for first time using high-resolution transmission electron microscope (HRTEM) imaging. Radiohaloes product high-energy α-particles emitted radioactive inclusions penetrating into surrounding over long (~1.8 Ga) timescales, in intense discoloration attributed to ionization events and damage. HRTEM analysis these radiohaloes reveals breakdown structure three...
Abstract We have applied mechanical exfoliation for the preparation of ultra-thin samples phyllosilicate mineral biotite. demonstrate that 'scotch tape' approach, which was made famous as an early method production single-atom-thick graphene, can be used sheet-silicate specimens are sufficiently thin to allow high-resolution transmission electron microscope (HRTEM) imaging achieved successfully while also being free from specimen artefacts often caused by ion-beam milling techniques....
One of the most challenging components UK nuclear legacy is Magnox sludge, arising from corrosion Mg alloy-clad irradiated metallic U fuel that has been stored in high pH ponds. The sludges mainly comprise hydroxide and carbonate phases, contaminated with fission products actinides, including Pu. Cementation deep geological disposal one option for long-term management this material, but there a need to understand how Pu may be leached waste, if it exposed groundwater. Here, we show cemented...
Evaluating the radiation stability of mineral phases is a vital research challenge when assessing performance materials employed in Geological Disposal Facility for radioactive waste. This report outlines setup and methodology efficiently allowing determination dose dependence damage to from single ion irradiated sample. The technique has been deployed using Dalton Cumbrian Facility's 5 MV tandem pelletron irradiate suite minerals with controlled α-particle ((4)He(2+)) beam. Such are proxies...
A method of drawing the cusped wave-fronts produced by refraction and reflection at a spherical surface graphic treatment elementary theory rainbow are described in Paper. The is based upon properties centre junction. In case which aplanatic points not available position junction-centre obtained geometry. By use junction-centres distribution successive foci on readily plotted. If it assumed that emergent portion effective pencil, as well incident portion, one parallel rays, then with regard...
The Paper contains a development of optical imagery based on elementary geometry, including limiting positions, but excluding cross-ratios, centres perspective, &c. method adopted is useful for teaching the properties systems to those who are not essentially students pure mathematics, and can be very satisfactorily used by capable draughtsmanship with mathematical instruments.
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