Transmission sputtering of titanium by 114 MeV fluorine ions

A perturbed hard core equation of state, applicable to both spherical and non-spherical cores, is described and tested with both molecular fluids and liquid metals (Na and U). The theory was found to be particularly accurate in describing the vapour pressure curve of molecular fluids but provides only a qualitative picture for liquid metals. The applicability of the equation to describe the thermodynamic properties of liquid UO₂ has been studied and a full set of thermodynamic data is reported.     

The enthalpy of formation of uf4 by fluorine bomb calorimetry

The energies of combustion in fluorine of two samples of uranium tetrafluoride, UF₄, were measured in a bomb calorimeter. Based on these measurements, the standard enthalpy of formation of crystalline UF₄, $\text{ΔH}{}^0{}_{\mathrm{f}}\text{(UF}{}_4\text{, c, 298.15 K) = ?1910.6 ± 2.0 kJ mol}{}^{-1}$ was derived.     

Radiation vulcanization of fluorine copolymers

Irradiation of rubberlike fluorine copolymers gives a rubber with poor physicochemical properties, but with fillers it is possible to obtain rubbers with valuable technical properties. The surface activity of the filler has a strong effect on the properties of the rubbers obtained. The most valuable properties are those of radiation rubbers that contain active channel black. They have a higher resistance to heat aging, are more stable to solvents and static deformation than the usual peroxide rubbers. In contrast to polytetrafluoroethylene and polytrifluorochloroethylene, rubberlike fluorine copolymers of the Kel-F type are cross-linked under the action of ionizing radiation. The degree of cross-linking of the fluorine copolymers is determined by their composition and the irradiation dose and medium. The presence of oxygen promotes a greater degree of cross-linking.     

Oxidation of Zircaloy-4 by oxygen and the production of water

The interaction of isotopic oxygen (¹⁸O₂) with Zircaloy-4 (Zry-4) at 150 and 300 K has been studied using Auger electron spectroscopy (AES) and temperature-programmed desorption (TPD) methods. AES reveals the oxidation of the Zry-4 surface, reflected in shifts of the Zr(MNV) and Zr(MNN) features by about 5.5 and 3.0 eV, respectively, for both adsorption temperatures. The O(KLL)/Zr(MNN) Auger peak-to-peak height ratios as a function of exposure show the same trends at both temperatures. Following ¹⁸O₂ adsorption at 150 or 300 K, TPD experiments show hydrogen desorption near 400 K that is attributed to the presence of a surface-stabilized form of hydrogen. Additionally, water (H₂¹⁸O and H₂¹⁶O) desorption below 200 K and above 700 K is observed after 150 K oxygen adsorption. However, after oxygen adsorption at 300 K the only significant desorption features are from isotopic water (H₂¹⁸O). These findings indicate that mass transport involving the near-surface region contributes to the observed desorption, and that this behavior is dependent on the original adsorption temperature. Charging experiments using D₂ prior to and after ¹⁸O₂ adsorption were also performed and support our conclusions about the role of surface–subsurface mass transport in this system.     

离心法分离锗同位素实验研究

采用气体离心法,以GeF4作为分离介质,通过国产离心机的单机实验成功分离了锗同位素,初步掌握了不同供料流量、分流比下GeF4离心分离的基本全分离系数,得到的基本全分离系数大于1.40,并且通过1-2-1级联实验及相关计算,对高丰度76GeF4产品的生产进行了模拟。实验证明,以GeF4为工作介质,采用国产离心机分离锗同位素可以获得高丰度的76GeF4产品。     

H-D体系的低温精馏分离实验研究

在自制低温精馏氢同位素装置上进行了H-D分离的初步实验.结果表明,以D/H比为1.4×10-4的氢气为原料,进料流量5 mol/h,运行120h后,再沸器的D/H比达1.27×10-2;增加原料气氘浓度,其浓集效果明显提高.随着再沸器中氘浓度增加,柱顶氘浓度增加,脱氘率降低.全回流实验下,再沸器加热功率增加,脱氘率增加,但造成柱压力明显增加.为控制精馏过程操作压力,选择适当的再沸器加热功率是必要的.     

Separation of Uranium Isotope by Plasma Centrifuge

A method of centrifugal separation of isotopes by electromagnetic means is presented. The principle proposed utilizes electromagnetic acceleration by the interaction between an electric current in a slightly ionized gas and an external magnetic field. The analysis shows that an azimuthal flow of 2.6 km/sec can be realized with a magnetic field of 200 gauss and an electric current of 1.5kA. The resulting centrifugal force is large enough to permit realization of a more compact concentration cascade than the conventional mechanical centrifuge.     

Hydrogen Isotope Separation by Plasma-Chemical Method

Deuterium transfer (exchange) reaction as shown in HDO+H₂=H₂O+HD was studied as a case similar to the tritium transfer reaction as shown in DTO+D₂=D₂O+DT, the first step in tritium isotope separation of the tritiated heavy water DTO. The transfer reaction was plasma-chemically catalyzed by allowing a gas mixture such as H₂O/D₂, D₂O/H₂, H₂O/HDO/H₂ or H₂O/D₂O/HDO/H₂ to flow through an atmospheric pressure discharge zone formed in a reaction chamber, the inner temperature of which was maintained just above 100°C. The plasma-chemical reactions diagnosed by infrared and emission spectroscopy revealed that the mixture underwent instantaneous deuterium transfer reactions as it passed the zone. The effectiveness of the method was demonstrated by high deuterium transfer rate, high separation factor of the transfer and a possibility of miniaturizing the separation facility.     

76Ge同位素的离心级联分离制备

高丰度⁷⁶Ge同位素在基础物理研究、医用放射性同位素领域有广泛应用,⁷⁶Ge富集的高纯锗探测器可用于探测无中微子双β衰变。为实现⁷⁶Ge同位素的分离制备,本文以四氟化锗（GeF₄）为介质,使用气体离心法开展研究。采用阶梯级联模型的计算结果表明,5轮分离可将⁷⁶Ge的丰度从天然丰度7.73%提升至90%以上。在21级阶梯级联实验平台上进行离心分离实验,调节流量、分流比等工况参数,制定分离流程,探索实验规律并优化实验方案。最终经过5轮分离,获得百克量级的丰度为94.21%的⁷⁶Ge同位素产品,为国产离心级联制备高丰度⁷⁶Ge产品及其工业化生产提供参考。     

Rapid Separation of Fission-Product Rare Earths and Yttrium by Electromigration

The separation of fission-product La, Ce, Pr, Nd and Y was performed in 4 min by electro-migration. As complexing agent, nitrilotriacetic acid was used at two concentrations of the NTA ion selected so as to optimize mutual separation of the elements. Rapid location of the zone on the paper strip reached after migration was obtained by color reaction of the carrier added to the irradiated sample. The purity of the elements thus separated was checked by γ-ray spectrometry. At the higher concentration of NTA ([[NTA]=1.0×10^?2M, pH=4.1) under which all of rare earths and Y migrate toward the anode, the elements were well separated from each other, although appreciable amounts of other F.P. were also found in each fraction. On the other hand, at the lower NTA concentration ([NTA]=4.0 × 10^?3M, pH=2.0) where the F.P. all migrate toward the cathode, each zone contained the isotopes of the respective element almost exclusively, except for a few small photo-peaks attributable to other elements. In each fraction, the 92.5 min ¹⁴²La and 14 min ¹⁴³La, the 14 min ¹⁴⁶Ce (24 min ¹⁴⁶Pr), the 24 min ¹⁴⁶Pr and 12 min ¹⁴⁷Pr, the 1.8 hr ¹⁴⁹Nd, the 20.3 min ⁹⁴Y and 10.9 min ⁹⁵Y were identified from the energies of photo-peaks and their decay rates.     

Potential and Local Efficiency of the Separation of Nonisotopic Binary Gas Mixture by Centrifuge

The balance of value, the separation potential, and the separation efficiency for nine isotopic binary mixture of gases are studied on the basis of a systematic application of local nonequilibrium thermodynamics and the Dirac axioms. In the first approximation of the kinetic theory, a universal classical expression for the potential is substantiated; this expression is valid for nonisotopic mixtures with arbitrary and not only weak or symmetric separation. It is established that the transition from molar to mass terms changes the potential. In contrast to the potential, the observed separation power of a system is invariant under a change of variables.