Magnetic Separation as a Plutonium Residue Enrichment Process

Avens, Larry R.; Gallegos, Ubaldo F.; McFarlan, James T.

doi:10.1080/01496399008050437

Cited by 13 publications

(4 citation statements)

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“…SEM–EDX showed discrete Pu particle association with certain metals (e.g., Cu and Zn). These elements were expected as they were present in waste streams as impurities from bomb reduction of Pu and as inclusions in Pu scrap solids. , Pu was also identified in association with Bi via bulk Bi L 3 -edge XANES (as bismite, Bi 2 O 3 ) in the Z9-4-5A sample. Although Bi was not identified in PFP wastes, it may have been a contaminant in the Pu feedstock.…”

Section: Discussionmentioning

confidence: 99%

Influences on Subsurface Plutonium and Americium Migration

Emerson

Pearce

Delegard³

et al. 2021

ACS Earth Space Chem.

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Plutonium (Pu) has been released to the environment worldwide, including approximately 1.85 × 1015 Bq (200 kg) of Pu from process waste solutions to unconfined soil structures at the Hanford Site in Washington State. The subsurface mobility of Pu is influenced by complex interactions with sediments, groundwater, and any co-contaminants within the waste stream. Previous investigations at Hanford have shown that Pu exists as discrete PuO2 particles forming before or after disposal, as secondary solid phases formed from waste interactions with sediments as adsorbed/incorporated species, and/or as dissolved species. In this research, new evidence is presented for the existence of PuO2, PuO2-Bi2O3 composites, and particles from burnt Pu metal in near-surface sediments where Pu-laden acidic process waste was disposed to sediments. Pu and americium (Am) L 3 X-ray absorption spectroscopy and density functional theory suggest that, in larger, more crystalline PuO2 particles, Am formed from radioactive decay is retained in the PuIVO2 structure as AmIV. The Pu and Am that were disposed of in an acidic waste stream have since migrated deeper into the subsurface with detection to at least 37 meters below ground surface. In contrast, Pu deposited near the ground surface from neutral pH waste is found to be homogeneously distributed and relatively immobile. Groundwater extractions performed on contaminated sediments indicate that both Pu and Am are recalcitrant, with Am being fractionally less extractable than Pu on a molar basis. These results suggest that the more mobile fraction of Am has migrated from the near-surface and may be present in the deeper sediments as a different phase than Pu. From these results, it is suggested that Pu and Am deposited from acidic wastes were initially mobile and became significantly less mobile as wastes were neutralized within the soil profile.

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Section: Discussionmentioning

confidence: 99%

Influences on Subsurface Plutonium and Americium Migration

Emerson

Pearce

Delegard³

et al. 2021

ACS Earth Space Chem.

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“…The reprocessing of the spent fuels comprises the methods for the recovery of such actinides from the waste material, and the recovered actinides can be reused, which diminishes hazardous radiation that could deteriorate the environment. There have been a number of techniques developed already for nuclear fuel reprocessing such as solvent extraction, ion exchange, electrophotolysis, precipitation, magnetic separation, volatilization, and molten fuel and coolant salt processing . However, the traditional methods to remove heavy metals from industrial wastewater and clean technologies due to their common drawbacks such as low selectivity, high capital and energy costs, slow separation kinetics, and secondary waste generation are not cost effective.…”

Section: Areas Of Nntmentioning

confidence: 99%

Advanced Nanomaterials for Nuclear Energy and Nanotechnology

2019

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The use of the latest engineered nanomaterials in nuclear energy systems has opened doors for improving the performance and safety of nuclear power. Nuclear nanotechnology (NNT) deals with the use of engineered nanomaterials for future nuclear energy applications. Herein, the recent progress in research and benefits of using nanomaterials in different areas of nuclear energy like nuclear fuel extraction and fabrication, fission product capturing, creating robust reactor materials, radiation sensing and monitoring, and radioactive waste separation and spent nuclear fuel reprocessing are summarized. Ongoing research around the world in this field is reviewed, including experimental and computational methods.

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“…Nuclear waste streams have traditionally been treated by solvent extraction and ion exchange . The PUREX (Plutonium Uranium Extraction) process, invented by Anderson and Asprey in 1940s, has become a standard nuclear reprocessing method to recover plutonium and uranium for reuse in mixed oxide (MOX) fuel. , Besides these two processes, many other methods have been developed including electrophotolysis, − precipitation, magnetic separation, volatilization, molten fuel and coolant salt processing . Some of these methods are in practical use, but research into alternative approaches that potentially simplify the remediation process is warranted.…”

Section: Introductionmentioning

confidence: 99%

Conjugates of Magnetic Nanoparticle—Actinide Specific Chelator for Radioactive Waste Separation

Kaur

Zhang

Martin

et al. 2013

Environ. Sci. Technol.

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A novel nanotechnology for the separation of radioactive waste that uses magnetic nanoparticles (MNPs) conjugated with actinide specific chelators (MNP-Che) is reviewed with a focus on design and process development. The MNP-Che separation process is an effective way of separating heat generating minor actinides (Np, Am, Cm) from spent nuclear fuel solution to reduce the radiological hazard. It utilizes coated MNPs to selectively adsorb the contaminants onto their surfaces, after which the loaded particles are collected using a magnetic field. The MNP-Che conjugates can be recycled by stripping contaminates into a separate, smaller volume of solution, and then become the final waste form for disposal after reusing number of times. Due to the highly selective chelators, this remediation method could be both simple and versatile while allowing the valuable actinides to be recovered and recycled. Key issues standing in the way of large-scale application are stability of the conjugates and their dispersion in solution to maintain their unique properties, especially large surface area, of MNPs. With substantial research progress made on MNPs and their surface functionalization, as well as development of environmentally benign chelators, this method could become very flexible and cost-effective for recycling used fuel. Finally, the development of this nanotechnology is summarized and its future direction is discussed.

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Magnetic Separation as a Plutonium Residue Enrichment Process

Cited by 13 publications

References 0 publications

Influences on Subsurface Plutonium and Americium Migration

Influences on Subsurface Plutonium and Americium Migration

Advanced Nanomaterials for Nuclear Energy and Nanotechnology

Conjugates of Magnetic Nanoparticle—Actinide Specific Chelator for Radioactive Waste Separation

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