与散裂中子靶物理相关的理论计算程序探讨 II厚靶计算

散裂中子靶是加速器驱动洁净核能系统的一个重要环节.相关的理论计算程序和蒙特 卡罗方法是研究该系统的散裂靶物理的一个重要手段.对相关程序进行了比对和介绍,并对SHIELD程序系统在中国的发展和在散裂靶物理上的应用作了介绍.     

Heavy density liquid metal spallation target studies for indian ADS programme

Department of Atomic Energy, India has taken up the development of ADS in view of many attractive features like inherent safety, capability to transmute large quantities of nuclear waste, better utilization of thorium etc. A roadmap has been finalized for the development of ADS. One of the key components of the ADS is the spallation target. Considering the neutron yield, thermal-hydraulics and radiation damage issues, we are proposing to develop spallation target based on heavy density liquid metals like lead and lead-bismuth-eutectic (LBE). Both window and windowless target configurations are presently being studied. In view of the various advantages we are also studying liquid metal flow circulation based on gas lift mechanism. An R&D programme has been initiated to address various physics and technology issues of ADS target. Under this programme, mercury and LBE experimental facilities are presently being set up. Along with these facilities, computational tools related to spallation physics (FLUKA) and CFD are being developed, and the existing ones are utilized to design the entire target loop as well as sub-systems. In this presentation the details of these activities are presented.      

磁约束聚变堆及ITER实验包层模块设计研究进展

目前国际上代表性的磁约束聚变反应堆设计包括美国的ARIES系列和APEX系列、欧洲的PPCS系列、日本的SSTR系列、中国的FDS系列设计,以及国际合作的国际热核聚变实验堆等。这些设计研究涉及到聚变能科学技术发展的各个方面,包括聚变实验堆、商用示范堆和商用动力电站等的设计研究、相关物理和技术发展以及相关的能源技术与经济策略研究等。简要介绍了上述设计研究领域的现状和发展趋势。The uhimate goal of the fusion program is to develop large scale power plants for the production of electricity. At present, there are many representative designs of magnetic confinement fusion reactors in the world,e.g. ARIES and APEX in USA, PPCS in EU, SSTR in Japan, FDS in China, and International Thermonuclear Experimental Reactor （ITER）. These studies cover many aspects on fusion experimental reactors, DEMO reactors, and commercial fusion power plants, including plasma physics, blanket technologies, material behavior, and technologies required to construct and operate such complex plants. The study status and development strategy in various countries are summarized and reviewed.     

Neutron cross-sections above 20 MeV for design and modeling of accelerator driven systems

One of the outstanding new developments in the field of partitioning and transmutation (P&T) concerns accelerator-driven systems (ADS) which consist of a combination of a high-power, high-energy accelerator, a spallation target for neutron production and a sub-critical reactor core. The development of the commercial critical reactors of today motivated a large effort on nuclear data up to about 20 MeV, and presently several million data points can be found in various data libraries. At higher energies, data are scarce or even non-existent. With the development of nuclear techniques based on neutrons at higher energies, nowadays there is a need also for higher-energy nuclear data. To provide alternative to this lack of data, a wide program on neutron-induced data related to ADS for P&T is running at the 20–180 MeV neutron beam facility at ‘The Svedberg Laboratory’ (TSL), Uppsala. The programme encompasses studies of elastic scattering, inelastic neutron production, i.e., (n, xn′) reactions, light-ion production, fission and production of heavy residues. Recent results are presented and future program of development is outlined.      

Broad energy spectrum of laser-accelerated protons for spallation-related physics

A beam of MeV protons, accelerated by ultraintense laser-pulse interactions with a thin target foil, is used to investigate nuclear reactions of interest for spallation physics. The laser-generated proton beam is shown (protons were measured) to have a broad energy distribution, which closely resembles the expected energy spectrum of evaporative protons (below 50 MeV) produced in GeV-proton-induced spallation reactions. The protons are used to quantify the distribution of residual radioisotopes produced in a representative spallation target (Pb), and the results are compared with calculated predictions based on spectra modeled with nuclear Monte Carlo codes. Laser-plasma particle accelerators are shown to provide data relevant to the design and development of accelerator driven systems.     

Beam dynamics study of RFQ for CADS with a 3D space-charge-effect

The ADS (accelerator driven subcritical system) project was proposed by the Chinese Academy of Sciences. The initial proton beams delivered from an electron cyclotron resonance ion source can be effectively accelerated by 162.5 MHz 4.2 m long room temperature radio-frequency-quadrupoles (RFQ) operating in CW mode. To test the feasibility of this physical design, a new Fortran code for RFQ beam dynamics study, which is space charge dominated, was developed. This program is based on Particle-In-Cell (PIC) technique in the time domain. Using the RFQ structure designed for the CADS project, the beam dynamics behavior is performed. The well-known simulation code TRACK is used for benchmarks. The results given by these two codes show good agreements. Numerical techniques as well as the results of beam dynamics studies are presented in this paper.     

Accelerator-driven sub-critical reactor system (ADS) for nuclear energy generation

In this talk we present an overview of accelerator-driven sub-critical reactor systems (ADS), and bring out their attractive features for the elimination of troublesome long-lived components of the spent fuel, as well as for nuclear energy generation utilizing thorium as fuel. In India, there is an interest in the programmes of development of high-energy and high-current accelerators due to the potential of ADS in utilizing the vast resources of thorium in the country for nuclear power generation. The accelerator related activities planned in this direction will be outlined.     

倍频纳秒激光驱动类氖锗X射线激光的研究

利用JB19等程序分别对基频和倍频激光驱动条件下类氖锗X射线激光进行了模拟计算,结果表明利用倍频激光驱动同样也能够获得高强度的类氖锗X射线激光输出,只是对驱动激光的输出要求要高3.3倍.尽管如此,这也为将来在大型激光装置上开展类氖系列X射线激光研究指明了方向.初步的实验研究也证实了利用倍频纳秒激光驱动能够获得类氖锗X射线激光输出的结果. 关键词： X射线激光 类氖锗 数值模拟     

Possible use of accelerator driven subcritical reactors for minor actinides incineration

The possible interest of accelerator driven subcritical reactors for minor actinides incineration is examined. The physics of neutron multiplying systems is recalled. The differences between critical and subcritical reactors' control are described, with emphasis on the importance of the delayed neutrons fraction. The minor actinides fuel evolution is studied with the conclusion that fast neutron spectra are clearly more efficient then thermal neutron spectra. It is, also, shown that characteristic times for incineration should be in the order of 10 years. The number of minor actinides incinerators necessary for 60 PWRs is estimated to be about 6 with total thermal power of 9 GW. These reactors will, also, be able to transmute essentially all ⁹⁹Tc and ¹²⁹I produced by the 60 PWR. The excess electricity cost for MA incineration is estimated to be about 5%.     

新一代干净的核能——加速器驱动的次临界堆

介绍了新一代干净的核能－加速器驱动的次临界堆的原因和国际研究进展，并对国内如何开展这方面的研究提出了建议。     

Atomic nucleus as the laboratory for symmetry tests. The SPIN program

Two complementary facilities for nuclear orientation of radioactive nuclei, based on hyperfine interactions at low temperatures obtained with top loading ³He?⁴He dilution refrigerators, have been developed at JINR Dubna and Charles University in Prague. These facilities are well suited for nuclear orientation studies practically of any nuclei of physical interest, which can be produced on JINR YASNAPP and DRIBs complexes. Wide variety of precise nuclear spectroscopy experiments with oriented nuclei is carried out with this technique-SPIN program at JINR. The physics potential of nuclear orientation experiments and the information, which can be obtained from the study of directional distribution of gamma radiation from oriented nuclei, are summarized. As the result of such nuclear orientation experiments extensive tests of different symmetry and supersymmetry schemes relevant to nuclear physics can be performed. Some examples of such symmetry and supersymmetry schemes in nuclei, which can be tested in the framework of SPIN program, are indicated.     

Simulation of n-qubit quantum systems: A computer-algebraic approach

During the last decade, the field of quantum computation has attracted a lot of interest and motivated many theoretical and experimental studies of n-qubit quantum systems. But apart from the promise of more efficient quantum algorithms, these investigations also revealed a number of obstacles which still have to be overcome in practice. In this context, the use of simulation programs has proved to be an appropriate method. In order to facilitate the simulation of n-qubit quantum systems, we present the Feynman software program to provide the necessary tools to define and to deal with quantum registers as well as the operators acting on them. Using an interactive design within the framework of the computer algebra system Maple, we hope that the Feynman software program will be useful not only for teaching the basic elements of quantum computing but also for studying their physical realization in the future. The text was submitted by the authors in English.     

Exploring Quantum Physics through Hands-On Projects,by D. Prutchi and S.R. Prutchi

In the last decade there have been extensive advances in the use of sonar systems for the mapping of the sea floor. Different sediment types can now be delineated and displayed in analogue form for subsequent mapping and analysis.

Earlier restrictions on operating depth have been overcome, and acoustic sensors in the side-scan sonar mode can now be used from ships at normal hydrographic survey speeds over the whole Continental Shelf.

Research effort at the University of Bath has led to the development of systems which are now widely used for cable survey problems, and for studying the transport of sediment in coastal waters. The geophysical use of these new techniques is still only at an early stage. With the greatly increased interest now in marine problems and in undersea technology, one may look forward to considerable development in this field of applied physics.     

Solid state physics at ISOLDE

Radioactive atoms have been used in solid state physics and in materials science for decades. Besides their classical applications as tracers for diffusion studies, nuclear techniques such as Mössbauer spectroscopy, perturbedγγ angular correlation,β-NMR, and emission channeling make use of nuclear properties (via hyperfine interactions or emittedα orβ particles) to gain microscopic information on structural and dynamical properties of solids. During the last decade, the availability of many different radioactive isotopes as clean ion beams at ISOL facilities like ISOLDE/CERN has triggered a new era involving methods sensitive to the optical and electronic properties of solids, especially in the field of semiconductor physics. This overview will browse through ongoing solid state physics experiments with radioactive ion beams at ISOLDE. A wide variety of problems is under study, involving bulk properties, surfaces and interfaces in many different systems like semiconductors, superconductors, magnetic systems, metals and ceramics.

     

论FeCr合金辐照损伤的多尺度模拟

铁素体/马氏体钢具有优异的抗辐照肿胀和抗腐蚀能力,是聚变堆、ADS和四代堆结构材料重要候选者之一.多尺度模拟在核武器自辐照损伤、压力容器辐照脆化、医学材料辐照损伤等方面有着广泛的应用.国际上围绕F/M FeCr合金辐照损伤开展了大量的多尺度模拟工作.论文概述了F/M FeCr合金辐照损伤多尺度模拟研究现状及进展,并针对目前存在的某些问题提出了解决建议. 关键词： 铁素体/马氏体FeCr合金 辐照损伤 多尺度模拟     

Accelerator development in India for ADS programme

At BARC, development of a Low Energy High Intensity Proton Accelerator (LEHIPA), as front-end injector of the 1 GeV accelerator for the ADS programme, has been initiated. The major components of LEHIPA (20 MeV, 30 mA) are a 50 keV ECR ion source, a 3 MeV Radio Frequency Quadrupole (RFQ) and a 20 meV drift tube linac (DTL). The Low Energy Beam Transport (LEBT) and Medium Energy Beam Transport (MEBT) lines match the beam from the ion source to RFQ and from RFQ to DTL respectively. Design of these systems has been completed and fabrication of their prototypes has started. Physics studies of the 20–1000 MeV part of the Linac are also in progress. In this paper, the present status of this project is presented.      

Molecular collisions: From near-cold to ultra-cold

In the past two decades, the revolutionary technologies of creating cold and ultracold molecules have provided cutting-edge experiments for studying the fundamental phenomena of collision physics. To a large degree, the recent explosion of interest in the molecular collisions has been sparked by dramatic progress of experimental capabilities and theoretical methods, which permit molecular collisions to be explored deep in the quantum mechanical limit. Tremendous experimental advances in the field have already been achieved, and the authors, from an experimental perspective, provide a review of these studies for exploring the nature of molecular collisions occurring at temperatures ranging from the Kelvin to the nanoKelvin regime, as well as for applications of producing ultracold molecules.     

医用放射性同位素99Mo/99mTc生产现状和展望

99mTc是目前临床诊断应用最为广泛的医用放射性同位素。现有医用99mTc主要通过在实验堆中辐照高浓缩235U生成的99Mo衰变得到,存在工艺复杂、成本高、长距离运输损失等弊端以及核扩散风险。此外,全球实验反应堆为数不多且面临老化、退役问题,也多次因计划内的维修或意外停产事件而使99mTc供应面临困难。本文从99Mo/99mTc的供求现状入手,分析了目前供应链中存在的主要问题,重点介绍了六种传统及新型99Mo/99mTc生产技术的原理、研究进展及其经济性效益。详细评述了三种99Mo/99mTc分离纯化工艺,提出了99Mo/99mTc生产的发展趋势和展望。其中,以加速器驱动裂变低浓缩铀盐溶液的生产方式具有无反应堆、无高浓缩铀、放射性废物少等优势,是未来的重点研究方向。同时,为减少99Mo/99mTc损失,提高产品质量,开发和优化与生产体系相适应的分离纯化工艺也势在必行。中国科学院核能安全技术研究所FDS中科凤麟核能团队设计开发的一种氘氚聚变中子源驱动的99Mo次临界生产系统方案,可获得27Ci/d的99Mo产量,能满足国内一个中等省份的医疗诊断需求。     

Nuclear physics and ideas of quantum chaos

The field nowadays called “many-body quantum chaos” was started in 1939 with the article by I.I. Gurevich studying the regularities of nuclear spectra. The field has been extensively developed recently, both mathematically and in application to mesoscopic systems and quantum fields. We argue that nuclear physics and the theory of quantum chaos are mutually beneficial. Many ideas of quantum chaos grew up from the factual material of nuclear physics; this enrichment still continues to take place. On the other hand, many phenomena in nuclear structure and reactions, as well as the general problem of statistical physics of finite strongly interacting systems, can be understood much deeper with the help of ideas and methods borrowed from the field of quantum chaos. A brief review of the selected topics related to the recent development is presented.