Effective Radiological Contamination Control and Monitoring Techniques In High Alpha Environments

Funke, Kevin C.

doi:10.1097/00004032-200302001-00011

Cited by 3 publications

(2 citation statements)

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“…Radionuclides released from nuclear test explosions, nuclear reactors, processing sites, and spent-nuclear-fuel repositories contaminate natural aqueous systems and create great environmental concerns. [1][2][3][4][5][6][7][8][9][10][11][12] To remedy contamination and assess the safety of long-term storage of spent fuel, knowledge of sorption/desorption and precipitation/solubility of radionuclides is required.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of Uranyl Species onto the Rutile (110) Surface: A Periodic DFT Study

Pan

Odoh

Asaduzzaman

et al. 2011

Chemistry A European J

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To model the structures of dissolved uranium contaminants adsorbed on mineral surfaces and further understand their interaction with geological surfaces in nature, we have performed periodic density funtional theory (DFT) calculations on the sorption of uranyl species onto the TiO(2) rutile (110) surface. Two kinds of surfaces, an ideal dry surface and a partially hydrated surface, were considered in this study. The uranyl dication was simulated as penta- or hexa-coordinated in the equatorial plane. Two bonds are contributed by surface bridging oxygen atoms and the remaining equatorial coordination is satisfied by H(2)O, OH(-), and CO(3)(2-) ligands; this is known to be the most stable sorption structure. Experimental structural parameters of the surface-[UO(2)(H(2)O)(3)](2+) system were well reproduced by our calculations. With respect to adsorbates, [UO(2)(L1)(x)(L2)(y)(L3)(z)](n) (L1=H(2)O, L2=OH(-), L3=CO(3)(2-), x≤3, y≤3, z≤2, x+y+2z≤4), on the ideal surface, the variation of ligands from H(2)O to OH(-) and CO(3)(2-) lengthens the U-O(surf) and U-Ti distances. As a result, the uranyl-surface interaction decreases, as is evident from the calculated sorption energies. Our calculations support the experimental observation that the sorptive capacity of TiO(2) decreases in the presence of carbonate ions. The stronger equatorial hydroxide and carbonate ligands around uranyl also result in U=O distances that are longer than those of aquouranyl species by 0.1-0.3 Å. Compared with the ideal surface, the hydrated surface introduces greater hydrogen bonding. This results in longer U=O bond lengths, shorter uranyl-surface separations in most cases, and stronger sorption interactions.

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Section: Introductionmentioning

confidence: 99%

Adsorption of Uranyl Species onto the Rutile (110) Surface: A Periodic DFT Study

Pan

Odoh

Asaduzzaman

et al. 2011

Chemistry A European J

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“…In this regard, the fundamental science of actinides is becoming more and more important. However, diverse species, abundant oxidation states (OS), and easy coordination with various ancillary ligands almost throughout all elements in the periodic table make the actinide chemistry rather complicated. , Among them, thermodynamically stable and kinetically inert hexavalent uranyl U VI O 2 2+ is the most prevalent form of uranium, representing 98% in the spent nuclear fuel and having an environmental implication. − Recent studies have found that the uranyl(VI) is able to interact with other actinyl or actinide to construct cation–cation interaction (CCIs) complexes in solution and solid state, − although CCIs are well recognized between pentavalent actinyl ions An V O 2 + (An = U, Np, and Pu). − …”

Section: Introductionmentioning

confidence: 99%

Accessibility of Uranyl–Plutonium Complex Supported by a Polypyrrolic Macrocycle: An Implication for Experimental Synthesis

Zheng

Chen

et al. 2018

Inorg. Chem.

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The reaction of (THF)(H 2 L)(U VI O 2 ) (L is a tetra-anion of polypyrrolic macrocycle) with An III Cp 3 (Cp = cyclopentadienyl) afforded two intriguing cation−cation interaction (CCI) complexes (i.e., uranyl-Np and -U), but did not yield the uranyl−Pu analogue. To complement and extend experimental results, a scalar relativistic density functional theory has been performed on the formation reactions and various relevant properties of (THF)(A 2 L)(OUO)−An(CpX) 3 (A = Li and H; An = Pu, Np, and U; X = Me, H, Cl, and SiMe 3 ). Inspired by a strategy that improves uranyl precursor reactivity, we utilized (THF)-(Li 2 L)(U VI O 2 ) instead to gain a uranyl−Pu complex. Reaction free energy is reduced even to be negative (i.e., undergoing an exergonic process), which provides the thermodynamic possibility for experimental synthesis. This manner is further rationalized by the lithiated precursor showing the increased Li−O endo bond, uranium oxidation ability (VI → V), and exo−oxo basicity, as well as the lithiated uranyl−Pu product having more amount of electron transfer and a stronger O exo −Pu bond (i.e., representing the CCI). Electronic structures and electron-transfer analyses reveal a U V −Pu IV oxidation state for the new complex. Applying the more reactive lithiated precursor also decreases the formation reaction energies of uranyl−An (An = Np and U) complexes. The second strategy via exploiting substituted Cp to raise the reactivity of the plutonium reactant does not work well.

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Operational Health Physics

Miller¹

2005

Health Physics

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A review of the operational health physics papers published in Health Physics and Operational Radiation Safety over the past fifteen years indicated seventeen general categories or areas into which the topics could be readily separated. These areas include academic research programs, use of computers in operational health physics, decontamination and decommissioning, dosimetry, emergency response, environmental health physics, industrial operations, medical health physics, new procedure development, non-ionizing radiation, radiation measurements, radioactive waste disposal, radon measurement and control, risk communication, shielding evaluation and specification, staffing levels for health physics programs, and unwanted or orphan sources. That is not to say that there are no operational papers dealing with specific areas of health physics, such as power reactor health physics, accelerator health physics, or governmental health physics. On the contrary, there have been a number of excellent operational papers from individuals in these specialty areas and they are included in the broader topics listed above. A listing and review of all the operational papers that have been published is beyond the scope of this discussion. However, a sampling of the excellent operational papers that have appeared in Health Physics and Operational Radiation Safety is presented to give the reader the flavor of the wide variety of concerns to the operational health physicist and the current areas of interest where procedures are being refined and solutions to problems are being developed.

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Effective Radiological Contamination Control and Monitoring Techniques In High Alpha Environments

Cited by 3 publications

References 0 publications

Adsorption of Uranyl Species onto the Rutile (110) Surface: A Periodic DFT Study

Adsorption of Uranyl Species onto the Rutile (110) Surface: A Periodic DFT Study

Accessibility of Uranyl–Plutonium Complex Supported by a Polypyrrolic Macrocycle: An Implication for Experimental Synthesis

Operational Health Physics

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