Methods for Recovering Molybdenum from High-Level Raffinate of Extraction Reprocessing of NPP Spent Fuel

A large set of experimental data obtained previously with real industrial products and model solutions were analyzed, and problems related to formation of precipitates of fission molybdenum compounds in various steps of NPP spent fuel reprocessing were outlined. Molybdenum-containing precipitates prevent partitioning of long-lived radionuclides from the raffinate of the first extraction cycle of spent fuel reprocessing. Comparative analysis of methods (precipitation, sorption, extraction) for removing molybdenum from this raffinate was performed, and flowsheets involving localization of Mo using a TBP-compatible extractant with acid additives were suggested. An experimental study was made on precipitation of molybdenum from its backwash, followed by preparation of nonvolatile forms suitable for incorporation by hot pressing, together with the other long-lived radionuclides, into polycrystalline matrices for long-term storage.     

Mathematical Models and Computer Simulation of Nitrogen Concentration Profiles in Pulse Plasma Nitrided Layers

Two materials, pure Fe and pure Al, were nitrided in a pulse plasma nitriding facility. The nitrogen profiles in surface layers and the surface phase structures of specimens nitrided at 500℃ for 8 h for Fe and for 6 h for Al were measured using the glow     

A Laser System for Real-Time Measurement of the 129I and NO2 Concentrations in a Spent Nuclear Fuel Reprocessing Medium

A laser system was developed for real-time detection of the global radionuclide ¹²⁹I and NO₂ during spent nuclear fuel reprocessing. This system was used for determining the concentrations of these substances in a gas stream under actual conditions of nitric acid dissolution of spent nuclear fuel at the Khlopin Radium Institute, Research and Production Association. The tests showed that the laser system is suitable for measuring both the ¹²⁹I and NO₂ concentrations directly in the gas phase during spent nuclear fuel reprocessing (this is essential for monitoring this process and controlling the dissolution cycle safety) and in the gases emitted by radiochemical enterprises. The sensitivity with respect to ¹²⁹I, achieved with the laser system developed, also makes it suitable for real-time monitoring of ¹²⁹I and NO₂ at the maximum permissible concentration (MAC) level. This will allow evaluation of the environmental condition of air in the working areas of radiochemical enterprises, as well as in residential areas.     

bcc-Fe空位浓度对辐照损伤影响的分子动力学模拟

中子辐照引起的位移级联能在金属中产生各种缺陷.通过三维分子动力学方法模拟了bcc-Fe在不同空位浓度下中子辐照的位移级联过程.模拟结果表明,在空位浓度0％和初始碰撞原子能量5keV的情形下,位移级联过程会出现大量空位、间隙原子团等缺陷.经过0.5ps后点缺陷数量NF达到最大值1632,之后其逐渐减少,10ps后稳定在6...     

Radiation-Chemical Behavior of TBP in Hydrocarbon and Chlorohydrocarbon Diluents under Conditions of Reprocessing of Spent Fuel from Nuclear Power Plants

Experiments were performed for comparative assessment of the effect of ionizing radiation on the service characteristics of 30% TBP solutions in various diluents: hexachlorobutadiene (HCBD), mixtures of n-paraffins (RED diluent), and fraction of naphthenic hydrocarbons (RZh diluent). The following main parameters were chosen for comparative assessment of the quality of irradiated extractant solutions: composition and behavior of diluent radiolysis products, effect of diluents on the TBP radiolysis, and aggregative stability of emulsions in the main operations of the extraction cycle. The service life of the extraction mixtures was estimated from variation of the above parameters with the irradiation dose. Principles for choosing solvents with increased service life under irradiation were substantiated.     

Mathematical Simulation of Dissolution of Rocks in the Course of Karsting Processes

Journal of Engineering Physics and Thermophysics - A mathematical model of dissolution of rocks has been developed with regard for the specifics of the dissolution processes in the porous space of...     

Strategic Separation of Technetium and Rare Metal Fission Products in Spent Nuclear Fuel: Solvent Extraction Behavior and Partitioning by Catalytic Electrolytic Extraction

Extraction behavior of Tc in the PUREX process was discussed on the basis of the observations at TRP, a semi-industrial scale reprocessing plant for spent LWR fuel in Tokai-mura. The Tc extraction in the HA/HS banks of the TRP was significantly enhanced by the coextraction with Zr(IV), while more than 99% of Tc was finally acccumulated in HLLW. Catalytic electrolytic extraction (CEE) was studied to separate Pd, Ru, Rh, Tc, Te, and Se, categorized as rare metal fission products (RMFP) in the HLLW. Cyclic reaction of metallic cations such as Pd^{2 +} or Fe^{2 +} can accelerate the electrochemical deposition of RuNO^{3 +}, Rh^{3 +}, and ReO₄ ^- owing, e.g., to the promoting effect of Pd adatoms or to behavior of Pd as mediator. Apart from being the first step for transmutation or other selective strategies for radioactive waste management containing long-lived fission products, the RMFP separation also offers alternative material resources to meet expanding demands for catalysts in fuel cell/hydrogen soft energy systems. Extended recycling of RMFPs is proposed as a new strategy on nuclear fuel reprocessing.     

Mathematical Simulation of Mass-Transfer Processes in Off-Furnace Degassing of Metal by Floating Inert Gas Bubbles

A mathematical model of mass-transfer processes in off-furnace degassing of metal in blasting by inert gas bubbles has been developed. The model allows for the effect of both the concentration of molten surfactants and the modes of floating of gas bubbles in the liquid bath on mass transfer and describes a wide class of mass-transfer processes in technologies, which differ in kind and composition of metals. The factor of resources and energy saving is determined. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 78, No. 3, pp. 68–71, May–June, 2005.     

Using Structural Equation Modeling (SEM) for the Study of Impurity Profiles of Drug Substances

The impurity profile is one of the most important quality characteristics of a drug substance. Although it is always desirable to determine the chemical structure of all impurities forming the impurity profile, unfortunately this is not always economically and technically feasible because of the extremely low concentrations at which some impurities may be found in the drug substance. Therefore, alternative approaches to the chemical analysis are needed for trying to determine the origin of the unidentified impurities.

In a previous study conducted by our group, based on exploratory (principal component and hierarchical cluster) analysis, we were able to suggest a hypothesis for explaining the origin of the unidentified impurities of a drug substance. However, there was still a concern that alternative hypotheses might explain the same phenomenon equally well. This article explores the application of recent developments in structural equation modeling for the systematic generation and selection of hypotheses (models) worthy of being confirmed by chemical research.     

Prediction of Crack Location in Deep Drawing Processes Using Finite Element Simulation

Sheet metal forming process like deep drawing subjected to large irreversible deformation. It leads to high strain localization zones and then internal or superficial micro defects. The deformation behavior and crack initiation in cylindrical deep drawing of aluminum alloy are simulated by the elasto-plastic finite element simulation. A1100-O and A2024-T4 sheet material are used in the simulation. Material properties based on the tensile and plane strain test is used in the simulation. Six cases are simulated in this study with different blank diameter. The simulated results are compared with the experimental results in terms of the crack location and critical punch displacement. The comparison of simulated results with experimental results shows a good agreement.     

Simulation of Wave Processes under Conditions of Friction of Rough Surfaces (Review)

We show that, under conditions of friction, there arise heat, deformation, and acoustic waves. We also describe the nature of their onset and analyze the statistical distribution of regular and irregular roughness on an actual discrete contact surface for different levels of structure and dimensions. We substantiate the possibility of development of new heat-dynamic models of temperature flashes with regard for the periodic discreteness of actual friction surfaces.     

Simulation of Thermal Processes in a Well with a Multibed System in the Extraction of Live Crude

Journal of Engineering Physics and Thermophysics - Based on the numerical model describing the nonisothermal motion of a two-phase fluid in a well with a multibed system, the problem of the takeoff...     

Detection of Low Sugar Concentration Solution Using Frequency Selective Surface (FSS)

Sugar is important in daily food intake since it is used as food preservative and sweetener. Therefore, is important to analyze the influence of sugar on the spectroscopic properties of the sample. Terahertz spectroscopy is proven to be useful and an efficient method for sugar detection as well as for future food quality industry. However, the lack of detection sensitivity in Terahertz Spectroscopy has prevented it from being used in a widespread spectroscopic analysis technology. In this paper, Frequency Selective Surface (FSS) using the Terahertz Spectroscopy Time Domain Spectrum (THz-TDS) which operates at terahertz frequency range has been demonstrated for application of sugar detection. The FSS is designed with a circle slot structure and has been optimized in line with the molecular resonance of glucose and fructose at different level concentration at 1.98 THz and 1.80 THz, respectively. Transmission magnitude of glucose and sucrose is inversely proportional with the level of sugar concentrations. The realization of the FSS structure is using electron beam lithography and wet etching technique. Results show that the FSS performance for glucose and sucrose reveal fair shifts in measured transmission magnitude from its original in CST by approximately 30%. The use of fabricated FSS with circle structure indicates that the concentration can be improved averagely at 25% for glucose and 13% for sucrose. Thus, it shows that the FSS circle structure combined with THz-TDS has the potential to become an alternative method for food sensing technology in the future.     

A New Control Scheme for Phase‐II Monitoring of Simple Linear Profiles in Multistage Processes

In this paper, a new control scheme is proposed for Phase‐II monitoring of simple linear profiles in multistage processes. In this scheme, an approach based on the U transformation is first applied to remove the effect of the cascade property involved in multistage processes. Then, a single max‐EWMA‐3 control statistic is derived based on the adjusted parameter estimates for simultaneous monitoring of all the parameters of a simple linear profile in each stage. Not only is the proposed scheme able to detect both increasing and decreasing shifts but it also has the feature of identifying the out‐of‐control parameter responsible for the source of process shift. Using extensive simulation experiments, the performance of the proposed method is evaluated and is compared with the ones of some other available methods for both weak and strong autocorrelations. Moreover, the diagnostic performance of the proposed method is evaluated. The results show that the proposed scheme performs well and works better than the competing methods. The application of the proposed method is illustrated at the end using a numerical example. Copyright © 2016 John Wiley & Sons, Ltd.     

固体氧化物燃料电池连接材料的研究进展

平板型燃料电池是固体电解质燃料电池的主要构成方式,而连接材料的研究是平板型燃料电池实用化研究的关键技术之一。本文简要介绍了连接材料的特点和主要存在的问题及今后的研究重点。     

多孔结构Bi2WO6光催化剂的制备及其模拟燃油催化氧化脱硫活性

采用水热法合成了多孔结构Bi₂WO₆光催化剂, 借助X射线衍射(XRD)、场发射扫描电子显微镜(FESEM)、透射电子显微镜(TEM)、X射线能量色散谱(EDS)、紫外-可见漫反射(UV-Vis-DRS)、N2吸附/脱附等测试手段对样品的物相组成、形貌、比表面-孔径分布和光吸收特性等进行了表征。考察了水热温度、水热反应时间对Bi₂WO₆的形貌、比表面-孔径分布和光吸收特性影响, 并探讨了Bi₂WO₆光催化剂对模拟燃油的脱硫活性。结果表明, 在强酸性条件下水热温度和水热时间对Bi₂WO₆的形貌、比表面积和催化活性影响显著, 190℃水热反应2 h所得Bi₂WO₆为新颖的鸟巢状微晶, 且鸟巢状Bi₂WO₆由片层状二级结构组装而成。XRD和EDS表明, 鸟巢状结构的Bi₂WO₆为正交晶系, 纯度较高。N₂吸附-脱附测试结果表明, 鸟巢状Bi₂WO₆具有多孔结构, 孔主要分布在10 nm, 比表面积大约为17.49 m²/g。催化活性测试结果表明, 三维介孔结构Bi₂WO₆具有较好的模拟燃油脱硫效果, 在空气流量为100 mL/min, 催化剂加入量为1.2 g/L, 可见光照射180 min, 模拟汽油脱硫率高达91.2%, 且催化剂的稳定性能较好。