Development of laser ion source for heavy ion applications

We have been developing a high-performance laser ion source (LIS) for practical applications since 2009. Ideally, the LIS should generate a carbon beam with a peak current of 20 mA and a pulse duration of over 1 μs. We selected a Nd:YAG laser with a Gaussian-coupled resonator as the laser source based on our experience of generating high-charge-state ion beams. This laser can produce fundamental pulses with a power of 650 mJ and durations of about 6 ns. The graphite target used is 10 cm high and 10 cm in diameter, as it can be irradiated with up to 10⁵ laser shots. The maximum extraction voltage was designed to be 50 kV. We have already finished designing the LIS and we commenced fabrication. We intend to measure the source performance by performing plasma and beam tests up to the end of March 2011.     

Benchmarks of 3D Laplace Equation Solvers in a Cubic Configuration for Streamer Simulation

The aim of this paper is to test a developed SOR R&B method using the Chebyshev accelerator algorithm to solve the Laplace equation in a cubic 3D configuration.Comparisons are made in terms of precision and computing time with other elliptic equation solvers proposed in the open source LIS library.The first results,obtained by using a single core on a HPC,show that the developed SOR R&B method is efficient when the spectral radius needed for the Chebyshev acceleration is carefully pre-estimated.Preliminary results obtained with a parallelized code using the MPI library are also discussed when the calculation is distributed over one hundred cores.     

Molecular laser isotope separation versus atomic vapor laser isotope separation

In this work, the competitive molecular and atomic laser isotope separation methods are investigated to evaluate the potential of each une for more economical fuel fabrication of enriched uranium celas which can be practically used in light water reactors (LWR). The advantages, drawbacks and feasibility of various techniques of laser isotope separation including AVLIS and the main MLIS methods such as MOLIS, CRISLA, and SILARC techniques have been reviewed. Laser isotope separation (LIS) deserves an intensive research, because laser techniques have a number of advantages over traditional ones, such as highly selective elementary separation event, possibility of separating the required isotope, low energy consumption, short start up time and practically single-stage production, which may economize fuel processing [11.     

Ge and Ti post-ion acceleration from laser ion source

Laser ion sources (LIS) are employed with success to generate, in vacuum, Ge and Ti ion beams with high current, ion energy, charge states and directivity.Nanoseconds infrared laser pulses, with intensities of the order of 10¹⁰ W/cm², induce high ablation in Ge and Ti targets. Ions are produced in vacuum with energy distribution following the Coulomb–Boltzmann-shifted distribution and they are ejected mainly along the normal to the target surface. The free ion expansion process occurs in a constant-potential chamber placed at 30 kV positive voltage. An electric field of 5 kV/cm was used to accelerate the ions emitted from the plasma at INFN-LNS laser facility. Time-of-flight technique is employed to measure the mean ion energies of the post-accelerated particles. Ion charge states and energy distributions were measured through an ion energy spectrometer.     

Sorption-Extraction Processes in Uranium Hydrometallurgy: Processing of Monometallic Uranium Ores

The method used to develop sorption-extraction processes in uranium hydrometallurgy over the last 50 years is examined. The first-generation sorption-extraction processes, ionites, and apparatus are described. Data for the second-generation sorption-extraction technology and improvement of apparatus are generalized.The third generation of these processes is characterized by the adoption of porous anionites AM-p and AMP-p in order to make the kinetic characteristics of the sorption and extraction processes closer to one another, by sorption leaching of uranium ores, and by adoption of double synergetic mixtures of extracting agents at the stage of repurification of the commercial reclaim and by the development of fast sorption processes for extracting uranium from productive solutions used in mound and underground leaching. The fourth-generation processes are characterized by the use of high-volume vinyl pyridine ionites, tertiary synergetic mixtures at the extraction stage, combined extraction-desorption processes, solid-phase regeneration of saturated ionites, and conversion of absorbed anions of uranyl-trisulfate into nitrate and chloride complexes. 1 figure.     

Comparison of coating processes in the development of aluminum-based barriers for blanket applications

Reduced activation ferritic-martensitic steels (RAFM), e.g. Eurofer 97, are envisaged in future fusion technology as structural material, which will be in direct contact with a flowing liquid lead–lithium melt serving as breeder material. Aluminum-based barrier layers had proven their ability to protect the structural material from corrosion attack in flowing Pb–15.7Li and to reduce tritium permeation into the coolant.Coming from scales produced by hot dipping aluminization (HDA), the development of processes based on electrochemical methods to produce defined aluminum-based scales on RAFM steels gained attention in research during the last years. Two different electrochemical processes are proposed: The first one, referred to as ECA process, is based on the electrodeposition of aluminum from volatile, metal-organic electrolytes. The other process called ECX is based on ionic liquids.All three processes exhibit specific characteristics, for example in the field of processability, control of coating thicknesses (low activation criteria) and heat treatment behavior. The aim of this article is to compare these different coating processes critically, whereby the focus is on the comparison of ECA and ECX processes. New results for ECX-process will be presented and occurring development needs for the future will be discussed.     

世界核电国家的发展战略历程与我国核电发展

概述世界上主要发展核电的国家的技术路线、发展战略历程及其经验与教训;当前国际上核电发展的动向及前景;我国核电中长期发展规划的目标任务;我国核电自主化取得的成绩、具备的能力以及为赶上国际先进水平所做的努力;我国核能开发利用的前景展望。     

低中放废物处置FEPs清单建立的方法研究

识别所有影响处置场长期安全的有关因素,即特征(Features)、事件(Events)和过程(Processes)(FEPs),是处置场安全全过程系统分析的关键过程之一。我国目前低中放固体废物处置场环境影响评价中未开展低中放处置场的FEPs识别和景象开发。本文拟以某处置场为例,对如何建立我国的低中放废物处置FEPs清单进行了初步的探讨。     

Scientific Principles, Technology, and Equipment for Hydrometallurgical Processing of Uranium and Complex Ores

The development, over the last 50 years, of a technology for leaching various types of monouranium and complex ores, processed at hydrometallurgical plants, is examined. Leaching processes and the equipment required for them (including autoclave processes) for silicate, aluminosilicate, iron-bearing, carbonate uranium ores and complex uranium-phosphorus-bearing, uranium-vanadium, and uranium-molybdenum ores are described.     

The Effects of Chemical (isotropic) and Anisotropic Etching Processes on the Roughening of Nanocomposite Substrates

Simulation results of roughening of nanocomposite materials during both isotropic and anisotropic etching processes based on the level set method are presented. It is clearly shown that the presence of two phases with different etching rates affects the development of surface roughness and that some roughness characteristics obey simple scaling laws. In addition, certain scaling laws that describe the time dependence of the rms roughness w for various etching processes and different characteristics of the nanocomposite materials are determined.     

Development of the methodology and approaches to validate safety and accident management

The article compares the development of the methodology and approaches to validate the nuclear power plant safety and accident management in Russia and advanced industrial countries. It demonstrates that the development of methods of safety validation is dialectically related to the accumulation of the knowledge base on processes and events during NPP normal operation, transients and emergencies, including severe accidents. The article describes the Russian severe accident research program (1987–1996), the implementation of which allowed Russia to reach the world level of the safety validation efforts, presents future high-priority study areas. Problems related to possible approaches to the methodological accident management development are discussed.     

PET发展的技术现状及展望

ＰＥＴ扫描仪是当今最昂贵的，最精密的医用诊断设备，本文就与ＰＥＴ扫描仪相关的技术（如闪烁体，光电转换器件，电子学系统，数据采集和图像重建系统以及ＰＥＴ系统设计等）发展的现状做了一个介绍，介绍对ＰＥＴ的发展前景给出了展望。     

The present level of the technology of uranium ore processing

The raw material basis of the uranium industry is presently formed by poor, often complex ores, which are processed on a very large scale. The net cost of uranium production based on this material has been reduced by employing processes which are more effective and economic and by extensive automation. The article gives a review of the present level and development trends of uranium ore processing (mechanical concentration, preparation, leaching, separation processes, sorption, extraction) and the conditions for the use of these processes for ores of different composition. The basic industrial systems of processing the principal types of ores are described. A detailed analysis is given of the basic technical-economic indices of uranium ore processing factories.     

诊断用放射性药物研究现状与展望

以放射性药物为基础的单光子断层扫描(SPECT)和正电子断层扫描(PET)已成为十分有效的诊断手段,可在分子水平反应活体功能和代谢过程。放射性药物的研发也为分子影像和核医学的发展提供了强有力的保障。国内放射性药物的研究已有坚实的基础,并且不断探索新的领域。本文介绍了近几年中国诊断用放射性药物领域的最新研究进展,对今后一段时期内中国放射性药物的发展进行了展望,并提出了加强加速器放射性核素开发、放射性药物研究等方面的建议,更好地为人类健康事业服务。     

低温喷嘴装置内流场的数值模拟研究

激光抑制凝聚法(CRISLA)是目前极具工业应用潜力的激光同位素分离(LIS)方法.在应用激光抑制凝聚法分离S同位素时,需要借助低温喷嘴装置获得低温过饱和S F6气体,因此该方法的实际分离性能和优化除与激光参数相关外,还依赖于低温喷嘴装置内的流动状态,为了研究低温喷嘴装置结构和设计参数对分离性能的影响规律,优化分离性能...     

Amplification process of a gas electron multiplier simulated by PIC-MCC model

The performance of a single gas electron multiplier(GEM) in pure Xe at an atmospheric pressure is investigated by Particle in Cell-Monte Carlo Collision(PIC-MCC) model.The micro development processes with electrons and ions distributions in space have been revealed.Based on the micro development processes,the macroscopic parameters such as GEM gain and the effective efficiency have also been obtained.The simulation results indicate that after tens of nanoseconds,electrons are collected by the readout electrode while the ions still exist in the gas space for several microseconds.The main signal current is formed by the electrons arriving at the readout electrode,but electrons and ions are also collected by the copper electrodes near the GEM hole and the thin Kapton film boundary.The simulated gain of GEM exponentially increases with the applied GEM voltage.With the PIC-MCC simulations,both the physical amplification and charging mechanisms in the GEM device can be well understood,which is beneficial to the device design.     

On the history of a stochastic ansatz for solving the transport equation

A very useful approximate tool for understanding the role of random material properties on solutions of the transport equation is described and its historical derivation given. The development of this stochastic tool, from its introduction by Randall, to its use in describing current problems involving dichotomic or pseudo-dichotomic Markov processes is discussed.     

高放废液岩石化的发展现状

本文介绍了高放废液岩石化的发展情况。这项高放废液处理技术经过十年的研究已发展到中试规模,并具备多种工艺,是一项有发展前途的高放废液处理技术。     

Chemistry and technology of Molten Salt Reactors - history and perspectives

Molten Salt Reactors represent one of promising future nuclear reactor concept included also in the Generation IV reactors family. This reactor type is distinguished by an extraordinarily close connection between the reactor physics and chemical technology, which is given by the specific features of the chemical form of fuel, representing by molten fluoride salt and circulating through the reactor core and also by the requirements of continuous ‘on-line’ reprocessing of the spent fuel. The history of Molten Salt Reactors reaches the period of fifties and sixties, when the first experimental Molten Salt Reactors were constructed and tested in ORNL (US). Several molten salt techniques dedicated to fresh molten salt fuel processing and spent fuel reprocessing were studied and developed in those days. Today, after nearly thirty years of discontinuance, a renewed interest in the Molten Salt Reactor technology is observed. Current experimental R&D activities in the area of Molten Salt Reactor technology are realized by a relatively small number of research institutions mainly in the EU, Russia and USA. The main effort is directed primarily to the development of separation processes suitable for the molten salt fuel processing and reprocessing technology. The techniques under development are molten salt/liquid metal extraction processes, electrochemical separation processes from the molten salt media, fused salt volatilization techniques and gas extraction from the molten salt medium.