One of the urgent tasks of the uranium industry in Kazakhstan is the extraction of radionuclide residues from spent uranium wells.We proposed to extract the remains of radionuclides from the drilled wells and to impro...One of the urgent tasks of the uranium industry in Kazakhstan is the extraction of radionuclide residues from spent uranium wells.We proposed to extract the remains of radionuclides from the drilled wells and to improve the radiation safety of the contaminated area.We conducted a chemical analysis of the content of radionuclides in the ore material.The radionuclides U,Th,Pa,Ra,Ac,Rn were extracted,which can be used in industry and medicine in Kazakhstan.展开更多
Individual monitoring of workers exposed to the risk of intake of actinides requires suitable methods for measuring low level of excreted activity. The current protocols used for actinides analysis in bioassay are usu...Individual monitoring of workers exposed to the risk of intake of actinides requires suitable methods for measuring low level of excreted activity. The current protocols used for actinides analysis in bioassay are usually complicated and highly time consuming. In this work, a protocol based on the microwave digestion of urines followed by the separation of actinides using calix[6]arene-based chromatography columns and their measurement by a quadrupole ICP-MS is developed and validated, for the first time, on urine samples containing the three actinides, U, Pu and Am. With this protocol, the total analysis time is about 2 days, including the mineralization of urine and the chromatographic separation of actinides. Detection limits of actinides in urine are determined and compared to those obtained after “dilute and shoot” ICP-MS analysis or after alpha spectrometry measurement.展开更多
Ⅰ. INTRODUCTION The well-known Pauling’s electron theory for metals and alloys established the empirical general equation of the single bond radii R(1) for transition elements to the 4th, 5th and 6th periods in the ...Ⅰ. INTRODUCTION The well-known Pauling’s electron theory for metals and alloys established the empirical general equation of the single bond radii R(1) for transition elements to the 4th, 5th and 6th periods in the periodic table. Yu Ruihuang first utilizes the form of Pauling’s R(1) equation but changes the physical meaning and thereby the real physical nature of展开更多
Ⅰ. INTRODUCTION The valence state changes of actinides are complicated by their electron structures, because the valence electron structures of an element are different in different compounds. For this reason, study ...Ⅰ. INTRODUCTION The valence state changes of actinides are complicated by their electron structures, because the valence electron structures of an element are different in different compounds. For this reason, study on the electron structures of metals and compounds of actinides is of important theoretical significance. The equation for calculating the single bond radii R(1) and the hybrid levels of valence 3 actinides have been established by Chen et al.,展开更多
The previously derived Lane consistent dispersive coupled-channel optical model for nucleon scattering on 232Th and 23Su nuclei is extended to describe scattering on even-even actinides with Z=90-98. A soft-rotator- m...The previously derived Lane consistent dispersive coupled-channel optical model for nucleon scattering on 232Th and 23Su nuclei is extended to describe scattering on even-even actinides with Z=90-98. A soft-rotator- model （SRM） description of the low-lying nuclear structure is used, where the SRM Hamiltonian parameters are adjusted to the observed collective levels of the target nucleus. SRM nuclear wave functions （mixed in K quantum number） have been used to calculate the coupling matrix elements of the generalized optical model. The ＂effective＂ deformations that define inter-band couplings are derived from the SRM Hamiltonian parameters. Conservation of nuclear volume is enforced by introducing a dynamic monopolar term to the deformed potential, leading to additional couplings between rotational bands. The fitted static deformation parameters are in very good agreement with those derived by Wang and collaborators using the Weizs^cker-Skyrme global mass model （WS4）, allowing use of the latter to predict cross sections for nuclei without experimental data. A good description of the scarce ＂optical＇experimental database is achieved. SRM couplings and volume conservation allow a precise calculation of the compound-nucleus formation cross sections, which is significantly different from that calculated with rigid-rotor potentials coupling the ground-state rotational band. The derived parameters can be used to describe both neutron- and proton-induced reactions.展开更多
Partitioning of actinides from lanthanides is pivotal for advancing nuclear waste management and sustaining nuclear energy development,yet it remains a formidable challenge due to the intricate chemical behaviors of t...Partitioning of actinides from lanthanides is pivotal for advancing nuclear waste management and sustaining nuclear energy development,yet it remains a formidable challenge due to the intricate chemical behaviors of these f-block elements.In this study,we introduce 3,6-di-2-pyridyl-1,2,4,5-tetrazine(L1),whose hydrolysis product of pyridine-2-carbox-aldehyde(pyridine-2-carbonyl)-hydrazone(L2)can fractionally crystallize U(Ⅵ)ions over Ln(Ⅲ)cations with high selectivity and efficiency.Through hydrolysis-induced C–N bond cleavage,L2 acts as a tetradentate ligand,coordinating with two UO_(2)^(2+) ions in a planar arrangement to form a zerodimensional cluster,[(UO_(2))2(μ_(3)-O)(L2)(CH_(3)COO)]·DMF(U-L2),while lanthanide ions(Ln=La,Pr,Nd,Sm,Eu,Gd,Tb,Yb,and Lu)remain in solution due to their inability to achieve similar coordination.This selective crystallization strategy yields exceptional separation factors(SFs)between U(Ⅵ)and Ln(Ⅲ),with a value of 756276 between U(Ⅵ)and Sm(Ⅲ),the highest reported to date.Furthermore,this fractional crystallization separation process can be achieved under mild ambient conditions with high SFs,enabling the development of a rapid,safe and energy-efficient strategy for once-through separation of high oxidation state actinides from lanthanides.展开更多
Four novel compounds based on hexanuclear thorium cluster were synthesized and characterized.Compound 1[Th_(6)(HPy C)_(8)(HCOO)_(4)]is formed by replacing formate ligands of preassembled thorium cluster[Th_(6)O_(4)(OH...Four novel compounds based on hexanuclear thorium cluster were synthesized and characterized.Compound 1[Th_(6)(HPy C)_(8)(HCOO)_(4)]is formed by replacing formate ligands of preassembled thorium cluster[Th_(6)O_(4)(OH)_(4)(H_(2)O)_(6)(HCOO)_(12)]with eight H_(2)Py C(4-pyrazolecarboxylic acid)under solvothermal conditions.Each of the HPy C^(-)ligands is coordinated with one Cu^(2+)to form the(4,8)-connected scu-net structure of compound 2[(Cu Cl_(2))_(2)Th_(6)(HPy C)_8(HCOO)_(4)].In compound 3[(Cu Cl_(2))_(2)Th_(6)(HPy C)_(10)(HCOO)_(4)],ten of the formate ligands of preassembled Th_(6)cluster are replaced by HPy C^(-)ligands.Compared with compound 2,the two extra HPy C^(-)ligands in the equatorial plane of the Th_(6)cluster in compound 3 are not further connected to copper ions.Therefore,the topology structure of compound 3 is same with that of compound 2.Compound 4[(Cu_(3)Cl_(2))(Cu Cl_(2))Th_(6)(Py C)_(3)(HPy C)_(4)(HCOO)_(5)]contains three kinds of metal nodes,Th_(6)cluster,Cu_(3)cluster and mononuclear Cu^(2+),and exhibits a novel(5,7)-connected net structure,which was first discovered in actinide MOFs.Furthermore,considering the satisfactory stability of compound 4 and its unsaturated metal nodes and Lewis acid sites,the catalysis of cycloaddition of CO_(2)was further studied.We found that this thorium-copper heterometallic cluster organic framework can be used as a potential actinide functional material for catalyzing the efficient CO_(2)conversion to value-added products.展开更多
We systematically calculated the multinucleon transfer reactions of ^(208)Os,^(208)Pt,^(208)Hg,^(208)Pb,^(208)Po,^(208)Rn,^(208)Ra,and ^(132,136) Xe when bombarded on ^(232) Th and ^(248) Cm at Coulomb barrier energie...We systematically calculated the multinucleon transfer reactions of ^(208)Os,^(208)Pt,^(208)Hg,^(208)Pb,^(208)Po,^(208)Rn,^(208)Ra,and ^(132,136) Xe when bombarded on ^(232) Th and ^(248) Cm at Coulomb barrier energies within the dinuclear system model.These results are in good agreement with the available experimental data.The influence of Coulomb and shell effects on actinide production in these reactions has been rigorously studied.We calculated and analyzed the potential energy surface (PES) and total kinetic energy (TKE) mass distributions for the reactions involving ^(208)Hg,^(208)Pb,and ^(208) Po with ^(248) Cm and ^(232)Th.The PES and TKE spectra shed light on the fragment formation mechanisms in multinucleon transfer reactions,with clear indications of isospin and shell effects.The production cross sections for multinucleon transfer products show a strong dependence on isobar projectiles with a mass number A=208.Isobar projectiles with high N/Z ratios are advantageous for generating neutron-rich target-like fragments.Conversely,products induced by isobar projectiles with larger charge numbers tend to shift toward proton-rich regions.The intertwining of the Coulomb potential and shell effect is evident in the production cross sections of actinide isotopes.Drawing from reactions induced by radioactive projectiles,we anticipate the discovery of several new actinide isotopes near the nuclear drip lines,extending our reach into the superheavy nuclei domain.展开更多
Internal contamination of actinides has led to significant health hazards to the public and workers in the context of nuclear power plant accidents,uranium ore mining,and reprocessing of the used fuel.An effective seq...Internal contamination of actinides has led to significant health hazards to the public and workers in the context of nuclear power plant accidents,uranium ore mining,and reprocessing of the used fuel.An effective sequestering agent that is able to remove accidentally incorporated actinides in vivo with low toxicity is always in urgent need.The molecular decorporation ligands have been the most widely researched agents for the past few decades,while preliminary studies of functionalized nanoparticles have shown their clear advantages in metal binding selectivity,toxicity,and oxidative stress alleviation.Herein,the state-of-the-art of those two types of decorporation agents is presented with special attention being paid on the correlation between the solution and solid-state chemistry of those agents with actinides and the corresponding decorporation efficacies.展开更多
A process for actinide(Ⅲ)and lanthanum(Ⅲ)extraction separation from high-level liquid waste(HLLW)was proposed,with N,N,N’,N’-tetraoctyl diglycolamide(TODGA)as the extractant,tri-n–butyl phosphate(TBP)as the phase...A process for actinide(Ⅲ)and lanthanum(Ⅲ)extraction separation from high-level liquid waste(HLLW)was proposed,with N,N,N’,N’-tetraoctyl diglycolamide(TODGA)as the extractant,tri-n–butyl phosphate(TBP)as the phase modifier and 2,6-bis[1-(propan-1-ol)-1,2,3-triazol-4-yl]pyridine(PyTri-Diol or PTD)as hydrophilic stripping agent.This‘hot test’was successfully carried out,achieving 99.92%removal of americium-241(^(241)Am)with a separation factor SF(Eu/Am)of 3.8×10^(3)in the actinide(Ⅲ)product solution.The results show that bisamide podand extractants can effectively realize the extraction and separation of actinide(Ⅲ)and lanthanum(Ⅲ)from Chinese commercial HLLW and thus have a bright practical application potential for the treatment of commercial HLLW.展开更多
Separation and recovery of U(Ⅵ)and Th(Ⅳ)from rare earth minerals is a very challenging work in rare earth industrial production.In the present study,a homemade membrane emulsification circulation(MEC)extractor was u...Separation and recovery of U(Ⅵ)and Th(Ⅳ)from rare earth minerals is a very challenging work in rare earth industrial production.In the present study,a homemade membrane emulsification circulation(MEC)extractor was used to separate U(Ⅵ)and Th(Ⅳ)from rare earth elements by using Cyphos IL 104 as an extractant.Batch experiments were carried out using a constant temperature oscillator to investigate the extraction parameters of the single element and the results indicated that Cyphos IL 104could reach the extraction equilibrium within 30 min for all the three elements,i.e.,U(Ⅵ),Th(Ⅳ),and Eu(Ⅲ).Besides,the MEC extractor possessed a strong phase separation ability.The extraction efficiencies of U(Ⅵ),Th(Ⅳ),La(Ⅲ),Eu(Ⅲ)and Yb(Ⅲ)increased with the increase of pH.La(Ⅲ),Eu(Ⅲ)and Yb(Ⅲ)were hardly extracted when pH≤1.50,which was beneficial for effectively separating U(Ⅵ)and Th(Ⅳ)from La(Ⅲ),Eu(Ⅲ)and Yb(Ⅲ).In the multi-stages stripping experiments,when the stripping stage number was 3,the effective separation could be achieved by using HCl and H_(2)SO_(4),since the stripping efficiency reached 80.0%and 100.0%for Th(Ⅳ)and U(Ⅵ),respectively.Slope method and FT-IR spectra showed that Cyphos IL 104 reacted with U(Ⅵ)and Th(Ⅳ)by chelation mechanism.The extraction of multi-elements indicated that U(Ⅵ)and Th(Ⅳ)could be well separated from the solution which contains all rare earth elements,and the extraction efficiencies of U(Ⅵ)and Th(Ⅳ)both were close to 100.0%.Based on the above experimental results,a flowchart for efficient separation of U(Ⅵ)and Th(Ⅳ)from rare earth elements was proposed.展开更多
Soft N-donor bis-triazin bipyridines derives(R-BTBP)are a type of very promising extratant for extraction and complexation with long-lived trivalent minor actinides over lanthanides from highly active liquid waste(HLW...Soft N-donor bis-triazin bipyridines derives(R-BTBP)are a type of very promising extratant for extraction and complexation with long-lived trivalent minor actinides over lanthanides from highly active liquid waste(HLW).In addition to minor actinides,R-BTBP also holds very strong complexation ability toward fission palladium.However,few studies have been focused on the separation and complexation with the fission product Pd(Ⅱ)by R-BTBP.Herein,the complexation behaviors of Pd(Ⅱ)with four typical R-BTBP ligands were systematically studied by single crystal X-ray diffraction,1H NMR titration and theoretical calculation.The effects of R-BTBP initial conformation and nitrate anions on the complexation behaviors of R-BTBP with Pd(Ⅱ)were thoughtfully analyzed.Both the 1:1 and 2:1 binuclear complexes could be formed between Pd(Ⅱ)and R-BTBP with initialⅡconformation in the presence of nitrate anions,while only one 1:1 type Pd(Ⅱ)complex could be formed for those with initial OO conformation.Without nitrate anion,only one 1:1 type complex was formed in solution.The structure of the 1:1 Pd(Ⅱ)/R-BTBP complex was firstly characterized by single crystal crystallography.DFT calculation results showed that a significant large rotational energy barrier(21.8~22.6 kcal/mol)must be overcome to form theⅡtype 2:1Pd(Ⅱ)complex for those OO type R-BTBP ligands,however which would not prevent them from forming the 1:1 type complex.展开更多
Ideas, solely related on the nuclear shell model, fail to give an interpretation of the experimental central role of 54Xe in the asymmetric fission of actinides. The same is true for the β-delayed fission of ...Ideas, solely related on the nuclear shell model, fail to give an interpretation of the experimental central role of 54Xe in the asymmetric fission of actinides. The same is true for the β-delayed fission of 180Tl to 80Kr and 100Ru. The representation of the natural isotopes, in the Z-Neutron Excess plane, suggests the importance of the of the Neutron Excess evolution mode in the fragments of the asymmetric actinide fission and in the fragments of the β-delayed fission of 180Tl. The evolution mode of the Neutron Excess, hinged at Kr and Xe, is directed by the 50 and 82 neutron magic numbers. The present isotope representation offers a frame for the interpretation of the post fission evaporation of neutrons, higher for the AL compared to the AH fragments, a tenet in nuclear fission. Further enlightened is the functional meaning of the 50 proton magic number, marking the start of the yield rise of the AH fragments in actinide fission.展开更多
One of the postponed problems of nuclear power (NP) is the problem of the management of long-lived radioactive waste (RAW), and, first of all, with minor actinides (MA), of which americium-241 is the most difficult. T...One of the postponed problems of nuclear power (NP) is the problem of the management of long-lived radioactive waste (RAW), and, first of all, with minor actinides (MA), of which americium-241 is the most difficult. The aim of this work is to study the efficiency of americium transmutation in a fast reactor with a heavy liquid metal coolant lead-bismuth eutectic alloy. The article presents the results of calculations of the transmutation of americium in the SVBR-100 reactor using standard uranium oxide fuel with the addition of americium-241. The obtained values of the rate of transmutation of americium are compared with similar values for the SVBR-100 reactors on MOX-fuel and in the BN-800 reactor.展开更多
A number of reports have indicated that a sizable percentage of the nation＇s experts in radiochemistry are nearing retirement age. This reality has been a concern since the 1970s, when declining numbers of radiochemi...A number of reports have indicated that a sizable percentage of the nation＇s experts in radiochemistry are nearing retirement age. This reality has been a concern since the 1970s, when declining numbers of radiochemists worldwide was first observed. Therefore, the NAMP （National Analytical Management Program） has organized a subcommittee focused on training and education in radiochemistry. To bolster interest and increase awareness in radiochemistry, NAMP is offering webinars developed by experts on different topics relevant to radiochemistry. This paper presents our accomplishments in developing these webinars and highlights our efforts in outreaching the national and international radiochemistry community.展开更多
In this article,a comprehensive study of the fission process of Th,U,Pu,and Cm isotopes using a Yukawa-folded meanfield plus standard pairing model is presented.The study focused on analyzing the effects of the pairin...In this article,a comprehensive study of the fission process of Th,U,Pu,and Cm isotopes using a Yukawa-folded meanfield plus standard pairing model is presented.The study focused on analyzing the effects of the pairing interaction on the fragment mass distribution and its dependence on nuclear elongation.The significant role of pairing interactions in the fragment mass distributions of^(230)Th,^(234)U,^(240)Pu,and^(246)Cm was demonstrated.Numerical analysis revealed that increasing the pairing interaction strength decreased the asymmetric fragment mass distribution and increased the symmetric distribution.Furthermore,the odd-even mass differences at symmetric and asymmetric fission points were examined,highlighting their sensitivity to changes in the pairing interaction strength.Systematic analysis of the Th,U,Pu,and Cm isotope fragment mass distributions demonstrated the effectiveness of the model in reproducing the experimental data.In addition,the effects of the zero-point energy and half-width parameter on the fragment mass distribution for^(240)Pu were explored.Thus,this study provides valuable insights into the fission process by emphasizing the importance of pairing interactions and their relationship with nuclear elongation.展开更多
In this work,we report a novel octa-nuclear uranyl(U8)motif[(UO2)8O4(μ3-OH)2(μ2-OH)2]4+embedded in a uranyl-oxalate coordination polymer(compound 1)based on a U-shaped linker with extra-long xylylene chains for stab...In this work,we report a novel octa-nuclear uranyl(U8)motif[(UO2)8O4(μ3-OH)2(μ2-OH)2]4+embedded in a uranyl-oxalate coordination polymer(compound 1)based on a U-shaped linker with extra-long xylylene chains for stabilizing the resulting high-nuclear motif through additional cross-linking connectivity.A comparison with dimeric and monomeric uranyl compounds obtained at different pH value from the same hydrothermal system reveals that,solution pH plays a vital role in formation of this octa-nuclear uranyl motif by promoting hydrolysis of uranyl source.Since high similarity of eight uranium centers in this nearly planar U8 motif here,overlapping and broadening of signals in fluorescence,infra-red(IR)and Raman spectra can be found.展开更多
The solid solubilities of 207 binary alloys based on the three actinide metals (Th, U and Pu) at room tem- perature are studied with the two theoretical schemes suggested by one of the present authors (ZBW).The re- su...The solid solubilities of 207 binary alloys based on the three actinide metals (Th, U and Pu) at room tem- perature are studied with the two theoretical schemes suggested by one of the present authors (ZBW).The re- sults show that the soluble elements can be distinguished from the insoluble ones by a parabola y_1=a--bx^2 or an ellipse (x_2,-m)~2/c^2+(y_2-n)~2/d^2=l with the total reliabilities of 87.9% and 92.3% respectively for the 207 binary alloys. The contants a and b in the parabola equation, and c, d, m and n in the ellipse equation can be related to some appropriate parameters for each host metal respectively. The reasons are discussed. From the theories the soluble elements in these actinide host metals that have not been measured yet can be predicted in the accuracies of the schemes.展开更多
In these studies the isotopic inventories and corresponding activities of important nuclides for different fuel cycles of a CANDU reactor have been compared. The calculations have been performed using the computer cod...In these studies the isotopic inventories and corresponding activities of important nuclides for different fuel cycles of a CANDU reactor have been compared. The calculations have been performed using the computer code WIMSD4. The isotopic inventories and activities have been calculated versus the fuel burn-up for the natural UO2 fuel, 1.2% enriched UO2 fuel and for the 0.45% PuO2-UO2 fuel. It is found that 1.2% enriched uranium fuel has the lowest activity as compared to other two fuel cycles and vice versa for the 0.45% PuO2-UO2 fuel.展开更多
In order to promote our understanding on electronic structure of actinide dioxides, we construct a tight-binding model composed of actinide 5f and oxygen 2p electrons, which is called f-p model. After the diagonalizat...In order to promote our understanding on electronic structure of actinide dioxides, we construct a tight-binding model composed of actinide 5f and oxygen 2p electrons, which is called f-p model. After the diagonalization of the f-p model, we compare the eigen-energies in the first Brillouin zone with the results of relativistic band-structure calculations. Here we emphasize a key role of f-p hybridization in order to understand the electronic structure of actinide dioxides. In particular, it is found that the position of energy levels of Г7 and Г8 states determined from crystalline electric field (CEF) potentials depends on the f-p hybridization. We investiagte the values of the Slater-Koster integrals for f-p hybridization, (fpσ) and (fpπ), which reproduce simultaneously the local CEF states and the band-structure calculation results. Then, we find that the absolute value of (fpπ) should be small in comparison with (fpσ) = 1 eV. The small value of |(fpπ)| is consistent with the condition to obtain the octupole ordering in the previous analysis of the f-p model.展开更多
文摘One of the urgent tasks of the uranium industry in Kazakhstan is the extraction of radionuclide residues from spent uranium wells.We proposed to extract the remains of radionuclides from the drilled wells and to improve the radiation safety of the contaminated area.We conducted a chemical analysis of the content of radionuclides in the ore material.The radionuclides U,Th,Pa,Ra,Ac,Rn were extracted,which can be used in industry and medicine in Kazakhstan.
文摘Individual monitoring of workers exposed to the risk of intake of actinides requires suitable methods for measuring low level of excreted activity. The current protocols used for actinides analysis in bioassay are usually complicated and highly time consuming. In this work, a protocol based on the microwave digestion of urines followed by the separation of actinides using calix[6]arene-based chromatography columns and their measurement by a quadrupole ICP-MS is developed and validated, for the first time, on urine samples containing the three actinides, U, Pu and Am. With this protocol, the total analysis time is about 2 days, including the mineralization of urine and the chromatographic separation of actinides. Detection limits of actinides in urine are determined and compared to those obtained after “dilute and shoot” ICP-MS analysis or after alpha spectrometry measurement.
文摘Ⅰ. INTRODUCTION The well-known Pauling’s electron theory for metals and alloys established the empirical general equation of the single bond radii R(1) for transition elements to the 4th, 5th and 6th periods in the periodic table. Yu Ruihuang first utilizes the form of Pauling’s R(1) equation but changes the physical meaning and thereby the real physical nature of
文摘Ⅰ. INTRODUCTION The valence state changes of actinides are complicated by their electron structures, because the valence electron structures of an element are different in different compounds. For this reason, study on the electron structures of metals and compounds of actinides is of important theoretical significance. The equation for calculating the single bond radii R(1) and the hybrid levels of valence 3 actinides have been established by Chen et al.,
基金Supported by International Atomic Energy Agency,through the IAEA Research Contract 19263the Spanish Ministry of Economy and Competitivity under Contracts FPA2014-53290-C2-2-P and FPA2016-77689-C2-1-R
文摘The previously derived Lane consistent dispersive coupled-channel optical model for nucleon scattering on 232Th and 23Su nuclei is extended to describe scattering on even-even actinides with Z=90-98. A soft-rotator- model （SRM） description of the low-lying nuclear structure is used, where the SRM Hamiltonian parameters are adjusted to the observed collective levels of the target nucleus. SRM nuclear wave functions （mixed in K quantum number） have been used to calculate the coupling matrix elements of the generalized optical model. The ＂effective＂ deformations that define inter-band couplings are derived from the SRM Hamiltonian parameters. Conservation of nuclear volume is enforced by introducing a dynamic monopolar term to the deformed potential, leading to additional couplings between rotational bands. The fitted static deformation parameters are in very good agreement with those derived by Wang and collaborators using the Weizs^cker-Skyrme global mass model （WS4）, allowing use of the latter to predict cross sections for nuclei without experimental data. A good description of the scarce ＂optical＇experimental database is achieved. SRM couplings and volume conservation allow a precise calculation of the compound-nucleus formation cross sections, which is significantly different from that calculated with rigid-rotor potentials coupling the ground-state rotational band. The derived parameters can be used to describe both neutron- and proton-induced reactions.
基金supported by the National Natural Science Foundation of China(U22B20139,22322609,22076152,and 22476158).
文摘Partitioning of actinides from lanthanides is pivotal for advancing nuclear waste management and sustaining nuclear energy development,yet it remains a formidable challenge due to the intricate chemical behaviors of these f-block elements.In this study,we introduce 3,6-di-2-pyridyl-1,2,4,5-tetrazine(L1),whose hydrolysis product of pyridine-2-carbox-aldehyde(pyridine-2-carbonyl)-hydrazone(L2)can fractionally crystallize U(Ⅵ)ions over Ln(Ⅲ)cations with high selectivity and efficiency.Through hydrolysis-induced C–N bond cleavage,L2 acts as a tetradentate ligand,coordinating with two UO_(2)^(2+) ions in a planar arrangement to form a zerodimensional cluster,[(UO_(2))2(μ_(3)-O)(L2)(CH_(3)COO)]·DMF(U-L2),while lanthanide ions(Ln=La,Pr,Nd,Sm,Eu,Gd,Tb,Yb,and Lu)remain in solution due to their inability to achieve similar coordination.This selective crystallization strategy yields exceptional separation factors(SFs)between U(Ⅵ)and Ln(Ⅲ),with a value of 756276 between U(Ⅵ)and Sm(Ⅲ),the highest reported to date.Furthermore,this fractional crystallization separation process can be achieved under mild ambient conditions with high SFs,enabling the development of a rapid,safe and energy-efficient strategy for once-through separation of high oxidation state actinides from lanthanides.
基金support of the National Natural Science Foundation of China(Nos.22076187,22122609)the Hunan Province Natural Science Foundation of China(No.2023JJ40530)+1 种基金the Scientific Research Fund of Hunan Provincial Education Department(No.22C0202)The National Science Fund for Distinguished Young Scholars(No.21925603)。
文摘Four novel compounds based on hexanuclear thorium cluster were synthesized and characterized.Compound 1[Th_(6)(HPy C)_(8)(HCOO)_(4)]is formed by replacing formate ligands of preassembled thorium cluster[Th_(6)O_(4)(OH)_(4)(H_(2)O)_(6)(HCOO)_(12)]with eight H_(2)Py C(4-pyrazolecarboxylic acid)under solvothermal conditions.Each of the HPy C^(-)ligands is coordinated with one Cu^(2+)to form the(4,8)-connected scu-net structure of compound 2[(Cu Cl_(2))_(2)Th_(6)(HPy C)_8(HCOO)_(4)].In compound 3[(Cu Cl_(2))_(2)Th_(6)(HPy C)_(10)(HCOO)_(4)],ten of the formate ligands of preassembled Th_(6)cluster are replaced by HPy C^(-)ligands.Compared with compound 2,the two extra HPy C^(-)ligands in the equatorial plane of the Th_(6)cluster in compound 3 are not further connected to copper ions.Therefore,the topology structure of compound 3 is same with that of compound 2.Compound 4[(Cu_(3)Cl_(2))(Cu Cl_(2))Th_(6)(Py C)_(3)(HPy C)_(4)(HCOO)_(5)]contains three kinds of metal nodes,Th_(6)cluster,Cu_(3)cluster and mononuclear Cu^(2+),and exhibits a novel(5,7)-connected net structure,which was first discovered in actinide MOFs.Furthermore,considering the satisfactory stability of compound 4 and its unsaturated metal nodes and Lewis acid sites,the catalysis of cycloaddition of CO_(2)was further studied.We found that this thorium-copper heterometallic cluster organic framework can be used as a potential actinide functional material for catalyzing the efficient CO_(2)conversion to value-added products.
基金supported by National Natural Science Foundation of China (Nos. 12105241, 12175072)Natural Science Foundation of Jiangsu Province (No. BK20210788)+3 种基金Jiangsu Provincial Double-Innovation Doctoral Program (No. JSSCBS20211013)University Science Research Project of Jiangsu Province (No. 21KJB140026)Lv Yang Jin Feng (No. YZLYJFJH2021YXBS130)Key Laboratory of High-Precision Nuclear Spectroscopy,Institute of Modern Physics,Chinese Academy of Sciences (No. IMPKFKT2021001)。
文摘We systematically calculated the multinucleon transfer reactions of ^(208)Os,^(208)Pt,^(208)Hg,^(208)Pb,^(208)Po,^(208)Rn,^(208)Ra,and ^(132,136) Xe when bombarded on ^(232) Th and ^(248) Cm at Coulomb barrier energies within the dinuclear system model.These results are in good agreement with the available experimental data.The influence of Coulomb and shell effects on actinide production in these reactions has been rigorously studied.We calculated and analyzed the potential energy surface (PES) and total kinetic energy (TKE) mass distributions for the reactions involving ^(208)Hg,^(208)Pb,and ^(208) Po with ^(248) Cm and ^(232)Th.The PES and TKE spectra shed light on the fragment formation mechanisms in multinucleon transfer reactions,with clear indications of isospin and shell effects.The production cross sections for multinucleon transfer products show a strong dependence on isobar projectiles with a mass number A=208.Isobar projectiles with high N/Z ratios are advantageous for generating neutron-rich target-like fragments.Conversely,products induced by isobar projectiles with larger charge numbers tend to shift toward proton-rich regions.The intertwining of the Coulomb potential and shell effect is evident in the production cross sections of actinide isotopes.Drawing from reactions induced by radioactive projectiles,we anticipate the discovery of several new actinide isotopes near the nuclear drip lines,extending our reach into the superheavy nuclei domain.
基金supported by grants from the National Natural Science Foundation of China(Nos.21976127,U2167222,21790370,22106116)the Natural Science Foundation of Jiangsu Province(No.BK20190044,BK20210736)+1 种基金funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)China Postdoctoral Science Foundation(No.2020M681716)。
文摘Internal contamination of actinides has led to significant health hazards to the public and workers in the context of nuclear power plant accidents,uranium ore mining,and reprocessing of the used fuel.An effective sequestering agent that is able to remove accidentally incorporated actinides in vivo with low toxicity is always in urgent need.The molecular decorporation ligands have been the most widely researched agents for the past few decades,while preliminary studies of functionalized nanoparticles have shown their clear advantages in metal binding selectivity,toxicity,and oxidative stress alleviation.Herein,the state-of-the-art of those two types of decorporation agents is presented with special attention being paid on the correlation between the solution and solid-state chemistry of those agents with actinides and the corresponding decorporation efficacies.
文摘A process for actinide(Ⅲ)and lanthanum(Ⅲ)extraction separation from high-level liquid waste(HLLW)was proposed,with N,N,N’,N’-tetraoctyl diglycolamide(TODGA)as the extractant,tri-n–butyl phosphate(TBP)as the phase modifier and 2,6-bis[1-(propan-1-ol)-1,2,3-triazol-4-yl]pyridine(PyTri-Diol or PTD)as hydrophilic stripping agent.This‘hot test’was successfully carried out,achieving 99.92%removal of americium-241(^(241)Am)with a separation factor SF(Eu/Am)of 3.8×10^(3)in the actinide(Ⅲ)product solution.The results show that bisamide podand extractants can effectively realize the extraction and separation of actinide(Ⅲ)and lanthanum(Ⅲ)from Chinese commercial HLLW and thus have a bright practical application potential for the treatment of commercial HLLW.
基金supported by the National Natural Science Foundation of China(Nos.11775214 and 51803205)the China Scholarship Council(No.201906345006)。
文摘Separation and recovery of U(Ⅵ)and Th(Ⅳ)from rare earth minerals is a very challenging work in rare earth industrial production.In the present study,a homemade membrane emulsification circulation(MEC)extractor was used to separate U(Ⅵ)and Th(Ⅳ)from rare earth elements by using Cyphos IL 104 as an extractant.Batch experiments were carried out using a constant temperature oscillator to investigate the extraction parameters of the single element and the results indicated that Cyphos IL 104could reach the extraction equilibrium within 30 min for all the three elements,i.e.,U(Ⅵ),Th(Ⅳ),and Eu(Ⅲ).Besides,the MEC extractor possessed a strong phase separation ability.The extraction efficiencies of U(Ⅵ),Th(Ⅳ),La(Ⅲ),Eu(Ⅲ)and Yb(Ⅲ)increased with the increase of pH.La(Ⅲ),Eu(Ⅲ)and Yb(Ⅲ)were hardly extracted when pH≤1.50,which was beneficial for effectively separating U(Ⅵ)and Th(Ⅳ)from La(Ⅲ),Eu(Ⅲ)and Yb(Ⅲ).In the multi-stages stripping experiments,when the stripping stage number was 3,the effective separation could be achieved by using HCl and H_(2)SO_(4),since the stripping efficiency reached 80.0%and 100.0%for Th(Ⅳ)and U(Ⅵ),respectively.Slope method and FT-IR spectra showed that Cyphos IL 104 reacted with U(Ⅵ)and Th(Ⅳ)by chelation mechanism.The extraction of multi-elements indicated that U(Ⅵ)and Th(Ⅳ)could be well separated from the solution which contains all rare earth elements,and the extraction efficiencies of U(Ⅵ)and Th(Ⅳ)both were close to 100.0%.Based on the above experimental results,a flowchart for efficient separation of U(Ⅵ)and Th(Ⅳ)from rare earth elements was proposed.
基金financially supported by the National Natural Science Foundation of China(Nos.91126021 and 21376210)Natural Science Foundation of Zhejiang Province(Nos.LY22B070003 and 2016R401088)。
文摘Soft N-donor bis-triazin bipyridines derives(R-BTBP)are a type of very promising extratant for extraction and complexation with long-lived trivalent minor actinides over lanthanides from highly active liquid waste(HLW).In addition to minor actinides,R-BTBP also holds very strong complexation ability toward fission palladium.However,few studies have been focused on the separation and complexation with the fission product Pd(Ⅱ)by R-BTBP.Herein,the complexation behaviors of Pd(Ⅱ)with four typical R-BTBP ligands were systematically studied by single crystal X-ray diffraction,1H NMR titration and theoretical calculation.The effects of R-BTBP initial conformation and nitrate anions on the complexation behaviors of R-BTBP with Pd(Ⅱ)were thoughtfully analyzed.Both the 1:1 and 2:1 binuclear complexes could be formed between Pd(Ⅱ)and R-BTBP with initialⅡconformation in the presence of nitrate anions,while only one 1:1 type Pd(Ⅱ)complex could be formed for those with initial OO conformation.Without nitrate anion,only one 1:1 type complex was formed in solution.The structure of the 1:1 Pd(Ⅱ)/R-BTBP complex was firstly characterized by single crystal crystallography.DFT calculation results showed that a significant large rotational energy barrier(21.8~22.6 kcal/mol)must be overcome to form theⅡtype 2:1Pd(Ⅱ)complex for those OO type R-BTBP ligands,however which would not prevent them from forming the 1:1 type complex.
文摘Ideas, solely related on the nuclear shell model, fail to give an interpretation of the experimental central role of 54Xe in the asymmetric fission of actinides. The same is true for the β-delayed fission of 180Tl to 80Kr and 100Ru. The representation of the natural isotopes, in the Z-Neutron Excess plane, suggests the importance of the of the Neutron Excess evolution mode in the fragments of the asymmetric actinide fission and in the fragments of the β-delayed fission of 180Tl. The evolution mode of the Neutron Excess, hinged at Kr and Xe, is directed by the 50 and 82 neutron magic numbers. The present isotope representation offers a frame for the interpretation of the post fission evaporation of neutrons, higher for the AL compared to the AH fragments, a tenet in nuclear fission. Further enlightened is the functional meaning of the 50 proton magic number, marking the start of the yield rise of the AH fragments in actinide fission.
文摘One of the postponed problems of nuclear power (NP) is the problem of the management of long-lived radioactive waste (RAW), and, first of all, with minor actinides (MA), of which americium-241 is the most difficult. The aim of this work is to study the efficiency of americium transmutation in a fast reactor with a heavy liquid metal coolant lead-bismuth eutectic alloy. The article presents the results of calculations of the transmutation of americium in the SVBR-100 reactor using standard uranium oxide fuel with the addition of americium-241. The obtained values of the rate of transmutation of americium are compared with similar values for the SVBR-100 reactors on MOX-fuel and in the BN-800 reactor.
文摘A number of reports have indicated that a sizable percentage of the nation＇s experts in radiochemistry are nearing retirement age. This reality has been a concern since the 1970s, when declining numbers of radiochemists worldwide was first observed. Therefore, the NAMP （National Analytical Management Program） has organized a subcommittee focused on training and education in radiochemistry. To bolster interest and increase awareness in radiochemistry, NAMP is offering webinars developed by experts on different topics relevant to radiochemistry. This paper presents our accomplishments in developing these webinars and highlights our efforts in outreaching the national and international radiochemistry community.
基金This work was supported by the National Natural Science Foundation of China(Nos.12275115 and 12175097)the Educational Department of Liaoning Province(No.LJKMZ20221410).
文摘In this article,a comprehensive study of the fission process of Th,U,Pu,and Cm isotopes using a Yukawa-folded meanfield plus standard pairing model is presented.The study focused on analyzing the effects of the pairing interaction on the fragment mass distribution and its dependence on nuclear elongation.The significant role of pairing interactions in the fragment mass distributions of^(230)Th,^(234)U,^(240)Pu,and^(246)Cm was demonstrated.Numerical analysis revealed that increasing the pairing interaction strength decreased the asymmetric fragment mass distribution and increased the symmetric distribution.Furthermore,the odd-even mass differences at symmetric and asymmetric fission points were examined,highlighting their sensitivity to changes in the pairing interaction strength.Systematic analysis of the Th,U,Pu,and Cm isotope fragment mass distributions demonstrated the effectiveness of the model in reproducing the experimental data.In addition,the effects of the zero-point energy and half-width parameter on the fragment mass distribution for^(240)Pu were explored.Thus,this study provides valuable insights into the fission process by emphasizing the importance of pairing interactions and their relationship with nuclear elongation.
基金National Natural Science Foundation of China(21671191,21577144,11405186)。
文摘In this work,we report a novel octa-nuclear uranyl(U8)motif[(UO2)8O4(μ3-OH)2(μ2-OH)2]4+embedded in a uranyl-oxalate coordination polymer(compound 1)based on a U-shaped linker with extra-long xylylene chains for stabilizing the resulting high-nuclear motif through additional cross-linking connectivity.A comparison with dimeric and monomeric uranyl compounds obtained at different pH value from the same hydrothermal system reveals that,solution pH plays a vital role in formation of this octa-nuclear uranyl motif by promoting hydrolysis of uranyl source.Since high similarity of eight uranium centers in this nearly planar U8 motif here,overlapping and broadening of signals in fluorescence,infra-red(IR)and Raman spectra can be found.
文摘The solid solubilities of 207 binary alloys based on the three actinide metals (Th, U and Pu) at room tem- perature are studied with the two theoretical schemes suggested by one of the present authors (ZBW).The re- sults show that the soluble elements can be distinguished from the insoluble ones by a parabola y_1=a--bx^2 or an ellipse (x_2,-m)~2/c^2+(y_2-n)~2/d^2=l with the total reliabilities of 87.9% and 92.3% respectively for the 207 binary alloys. The contants a and b in the parabola equation, and c, d, m and n in the ellipse equation can be related to some appropriate parameters for each host metal respectively. The reasons are discussed. From the theories the soluble elements in these actinide host metals that have not been measured yet can be predicted in the accuracies of the schemes.
文摘In these studies the isotopic inventories and corresponding activities of important nuclides for different fuel cycles of a CANDU reactor have been compared. The calculations have been performed using the computer code WIMSD4. The isotopic inventories and activities have been calculated versus the fuel burn-up for the natural UO2 fuel, 1.2% enriched UO2 fuel and for the 0.45% PuO2-UO2 fuel. It is found that 1.2% enriched uranium fuel has the lowest activity as compared to other two fuel cycles and vice versa for the 0.45% PuO2-UO2 fuel.
文摘In order to promote our understanding on electronic structure of actinide dioxides, we construct a tight-binding model composed of actinide 5f and oxygen 2p electrons, which is called f-p model. After the diagonalization of the f-p model, we compare the eigen-energies in the first Brillouin zone with the results of relativistic band-structure calculations. Here we emphasize a key role of f-p hybridization in order to understand the electronic structure of actinide dioxides. In particular, it is found that the position of energy levels of Г7 and Г8 states determined from crystalline electric field (CEF) potentials depends on the f-p hybridization. We investiagte the values of the Slater-Koster integrals for f-p hybridization, (fpσ) and (fpπ), which reproduce simultaneously the local CEF states and the band-structure calculation results. Then, we find that the absolute value of (fpπ) should be small in comparison with (fpσ) = 1 eV. The small value of |(fpπ)| is consistent with the condition to obtain the octupole ordering in the previous analysis of the f-p model.
