Activation Characteristics of Fuel Breeding Blanket Module in Fusion Driven Subcritical System

Shortage of energy resources and production of long-lived radioactivity wastes from fission reactors are among the main problems which will be faced in the world in the near future. The conceptual design of a fusion driven subcritical system (FDS) is underway in Institute of Plasma Physics, Chinese Academy of Sciences. There are alternative designs for multi-functional blanket modules of the FDS, such as fuel breeding blanket module (FBB) to produce fuels for fission reactors, tritium breeding blanket module to produce the fuel, i.e. tritium, for fusion reactor and waste transmutation blanket module to try to permanently dispose of long-lived radioactivity wastes from fission reactors, etc. Activation of the fuel breeding blanket of the fusion driven subcritical system (FDSFBB) by D-T fusion neutrons from the plasma and fission neutrons from the hybrid blanket are calculated and analysed under the neutron wall loading 0.5 MW/m2 and neutron fluence 15 MW.yr/m2. The neutron spectrum is calculated with the worldwide-used transport code MCNP/4C and activation calculations are carried out with the well known European inventory code FISPACT/99 with the latest released IAEA Fusion Evaluated Nuclear Data Library FENDL-2.0 and the ENDF/B-V uranium evaluated data. Induced radioactivities, dose rates and afterheats, etc, for different components of the FDS-FBB are compared and analysed.     

Fabrication of Nano-Columnar Tungsten Films and Their Deuterium and Helium Ion Irradiation Effects

Nuclear fusion energy for electricity generation is drawing significant attention, due to the fact that it is a clean, safe, and environmentally friendly energy source. The plasma facing material （PFM） is one of the key factors that determine the development of fu- sion reactors. The fusion energy system requires ex- cellent performance of PFMs under high heat flux de- position and particles irradiation. PFMs not only are exposed to unprecedented steady-state and tran- sient power fluxes, but also are bombarded with un- precedented neutron fluxes. In nuclear fusion reactors, the PFM suffers from high-energy （14MeV） neutron irradiation and a high heat flux of ～10MW/m2. A variety of point defects （e.g., interstitials, vacan- cies, helium, and hydrogen gas atoms） are produced in the process of irradiation through atomic displace- ment and nuclear transformation. These point defects form defect clusters （e.g., voids and interstitial loops） and thus change the mechanical properties and mi- crostructure of the material even to the extent that their structural integrity is compromised.     

重离子惯性聚变的研究

本文描述了重离子惯性聚变的研究现状和用于重离子惯性聚变的重离子加速器． The present researching status and the heavy ion accelerators used for inertial fusion of heavy ions are decribed in the paper.     

Effects of a liquid lithium curtain as the first wall in a fusion reactor plasma

This paper explores the effect of a liquid lithium curtain on fusion reactor plasma, such curtain is utilized as the first wall for the engineering outline design of the Fusion Experimental Breeder （FEB-E）. The relationships between the surface temperature of a liquid lithium curtain and the effective plasma charge, fuel dilution and fusion power production have been derived. Results indicate that under normal operation, the evaporation of liquid lithium does not seriously affect the effective plasma charge, but effects on fuel dilution and fusion power are more sensitive. As an example, it has investigated the relationships between the liquid lithium curtain flow velocity and the rise of surface temperature based on operation scenario II of the FEB-E design with reversed shear configuration and high power density. Results show that even if the liquid lithium curtain flow velocity is as low as 0.5 m/s, the effects of evaporation from the liquid lithium curtain on plasma are negligible. In the present design, the sputtering of liquid lithium curtain and the particle removal effects of the divertor are not yet considered in detail. Further studies are in progress, and in this work implication of lithium erosion and divertor physics on fusion reactor operation are discussed.[第一段]     

Opacity enhanced by the localization of electrons

Plasmas absorbing and scattering photons are often described according to the conception of opacity. The opacity in hot, dense plasmas is crucial in many fields, including astrophysics and controlled nuclear fusion. It is a difficult problem because of many complex mechanisms involving,for instance, excited states, line broadenings, relativistic effects, and two-photon contributions. Studies on opacity.     

Effects of Thermal Treatments on Helium Retention and Thermal Desorption Behaviors in a V-4Ti Aalloy

Vanadium alloys are considered as the promising first wall and structure materials of the future fusion reactors owing to their perfect low neutron-induced radioactivity and good high temperature performance. Helium retention and thermal desorption behaviors are key issues for the applications of vanadium alloys in fusion reactors since helium can be produced by helium discharge cleaning and neutron transmutation. A. van Veen groupt investigated helium trapping and thermal desorption mechanisms in vanadium alloys by using 1 keV helium ion irradiation to the fluence of 10^13～10^14He/cm^2, and the influenee of pre-annealing treatments on helium trapping. Two group of peaks were found at the thermal helium desorption spectrum. They thought one was due to helium-vacancyimpurity clusters and the other was corresponding to helium trapping into pre-existing traps, such as fine-size precipitates.     

Microstructure and Mechanical Properties of Ti3SiC2 Irradiated by Carbon Ions

Thanks to its noteworthy mechanical properties, excellent damage tolerance and good thermal stability, the Ti3SiC2 ternary compound has attracted great concern and has been considered as a potential structural component material for the 4th generation of reactors （e.g., gas fast nuclear reactors） and future fusion reactors. The outstanding properties are due to the nanolameIlar structure which imparts characteristics of both metals and ceramics to this material In our work, Ti3SiC2 samples have been irradiated by C^＋ ions with a high fluence of 1.78 × 10^17 ions/cm^2 at a range of temperatures from 120℃～850℃. Subsequently, series of characterization techniques including synchrotron irradiation x-ray diffraction, scanning electron microscopy and nano-indentation are carried out to understand the changes of microstructure and mechanical properties. The composition exhibits high damage tolerant properties and a high recovery rate through the analysis, especially at high temperature. The minimum damage to an irradiated sample appears around 350℃ in the temperature range 120℃-550℃. At a high irradiation temperature, a significant reduction in the damage can be achieved and an almost complete lack of damage compared with an un-irradiated sample is revealed at the temperature of 850℃.     

受控热核聚变发展现况

核聚变动力的应用将提供几乎是无限、清洁的新一代能源．当前已经看到受控热核聚变的科学可能性,在利用核聚变生产动力之前,还要解决其工艺技术可行性及经济竞争能力等问题．聚变裂变混合堆是改善其经济性和减少工艺技术难点的方向之一,还可创造一个核能利用的有效途径． An almost limitless and clean source of energy for future generation should be provided by the successful use of nuclear fusion for generating power.At present the scien-tific feasibility of controlled nuclear fusion is visible and before fusion can be harnessed for generating power,it will be necessary to develop suitable technology and to prove economic viability.The fusion-fission hybrid reactor is one way to improve the economy and to reduce the technological difflculties...     

300＃堆在线产氚回路及其应用

本文介绍了３００~＃堆在线产氚回路的组成及其主要指标、回路运行和释氚实验概况,阐明了在线产氚回路在聚变裂变混合堆包层产氚研究中的应用和前景． An in-pile tritium production apparatus in SPRR-300 and its main charactersare introduced. The operation of the apparatus and the tritium release experiments arebriefly described. The utilization of the apparatus in tritium production study of fusionfission hybrid reactor blanket and its future are reviewed.     

Prospects for and problems of using light-water supercritical-pressure coolant in nuclear reactors in order to increase the efficiency of the nuclear fuel cycle

Trends in the development of the power sector of the Russian and world power industries both at present time and in the near future are analyzed. Trends in the rise of prices for reserves of fossil and nuclear fuels used for electricity production are compared. An analysis of the competitiveness of electricity production at nuclear power plants as compared to the competitiveness of electricity produced at coal-fired and natural-gas-fired thermal power plants is performed. The efficiency of the open nuclear fuel cycle and various versions of the closed nuclear fuel cycle is discussed. The requirements on light-water reactors under the scenario of dynamic development of the nuclear power industry in Russia are determined. Results of analyzing the efficiency of fuel utilization for various versions of vessel-type light-water reactors with supercritical coolant are given. Advantages and problems of reactors with supercritical-pressure water are listed.     

激光聚变驱动器的光束相干性及其控制:回顾与展望

高功率强激光与物质相互作用蕴藏着丰富的非线性效应,激光聚变驱动器的光束具有高度相干性,它在光束传输过程中极大地凸显了这种效应,并不可避免地制约着激光功率的提升和激光能量的有效利用。回顾激光聚变驱动器的发展史,在提升激光输出能力的主线外,还存在一条与光束相干性做斗争的暗线贯穿其中。以激光与物质相互作用为牵引,从高功率强激光传输中非线性效应抑制和激光等离子体相互作用的抑制两方面回顾了激光聚变驱动器光束相干性的控制现状,并针对潜在需求,展望了未来高功率激光发展的创新技术。     

Electric-arc plasma-chemical reactors of separated,single-chamber,and combined types

A wide variety of electric-arc reactors are involved in different areas of science and technologies. Therefore, a demand arose for their systematization. Here we present the classification of most existing types of electric-arc reactors regarding the mutual positioning of plasma-generation and reaction zones. There are three types of reactors: separated, single-chamber, and combined type. Different engineering solutions in each type led to some scatter in the thermal efficiency, power range, lifetime, and other results. No consideration has been given to the reactors of single-chamber heating. They are very special and require individual researches.     

Microstructure change in deuterium implanted CLAM steel induced by electron irradiation

As Reduced Activation Ferritic/Martensitic (RAFM) steel is considered the primary candidate for use as a structural material in fusion power reactors,many countries are developing different kinds of RAFM.China is developing new CLAM (China Low Activation Martensitic) steel.The study investigates microstructural changes in CLAM steel implanted with deuterium ions induced by 1250 keV electron irradiation from R.T.to 873 K,and observes both the growth and shrinkage of the defect clusters produced by deuterium ...     

Advantages of Production of New Fissionable Nuclides for the Nuclear Power Industry in Hybrid Fusion-Fission Reactors

A concept of a large-scale nuclear power engineering system equipped with fusion and fission reactors is presented. The reactors have a joint fuel cycle, which imposes the lowest risk of the radiation impact on the environment. The formation of such a system is considered within the framework of the evolution of the current nuclear power industry with the dominance of thermal reactors, gradual transition to the thorium fuel cycle, and integration into the system of the hybrid fusion-fission reactors for breeding nuclear fuel for fission reactors. Such evolution of the nuclear power engineering system will allow preservation of the existing structure with the dominance of thermal reactors, enable the reprocessing of the spent nuclear fuel (SNF) with low burnup, and prevent the dangerous accumulation of minor actinides. The proposed structure of the nuclear power engineering system minimizes the risk of radioactive contamination of the environment and the SNF reprocessing facilities, decreasing it by more than one order of magnitude in comparison with the proposed scheme of closing the uranium–plutonium fuel cycle based on the reprocessing of SNF with high burnup from fast reactors.     

Radiation effect of neutrons produced by D–D side reactions on a D–3He fusion reactor

One of the most important characteristics in D–³He fusion reactors is neutron production via D–D side reactions. The neutrons can activate structural material, degrading them and ultimately converting them into high-level radioactive waste, while it is really costly and difficult to remove them. The neutrons from a fusion reactor could also be used to make weapons-grade nuclear material, rendering such types of fusion reactors a serious proliferation hazard. A related problem is the presence of radioactive elements such as tritium in D–³He plasma, either as fuel for or as products of the nuclear reactions; substantial quantities of radioactive elements would not only pose a general health risk, but tritium in particular would also be another proliferation hazard. The problems of neutron radiation and radioactive element production are especially interconnected because both would result from the D–D side reaction. Therefore, the presentation approach for reducing neutrons via D–D nuclear side reactions in a D–³He fusion reactor is very important. For doing this research, energy losses and neutron power fraction in D–³He fusion reactors are investigated. Calculations show neutrons produced by the D–D nuclear side reaction could be reduced by changing to a more ³He-rich fuel mixture, but then the bremsstrahlung power loss fraction would increase in the D–³He fusion reactor.     

Nuclear Power System Based on Fission and Fusion Reactors is the Strategic Line of Nuclear Power Industry Development

Physics of Atomic Nuclei - The strategic line of development of a nuclear power system based on fission and fusion reactors which ensures electricity generation on a specified scale, solves the...     

The key role of heat exchangers in advanced gas-cooled reactor plants

The use of helium as a nuclear reactor coolant has been successfully demonstrated in plants built and operated in the U.K., U.S.A., and Germany. Following the pioneering proof of principle plant, two small power plants were operated for several years and this led to the construction of two commercial power stations. For the next generation of gas-cooled reactors new criteria have been developed, namely, the plants will be smaller, simpler, safer and of lower cost. The base case Modular High-Temperature Gas-Cooled Reactor (MHTGR) utilizes existing technology to offer a tried and proven power generating plant using a conventional steam turbine power conversion system that could be in utility service just after the turn of the century. The capability of the MHTGR to operate at very high temperatures will be exploited early in the next century in the form of advanced variants to meet the needs of the power generation and process industries. A key component in the MHTGR is the heat exchanger, since this is where the reactor thermal energy is transferred to the prime-mover or process system. This paper addresses the various roles that heat exchangers will play in advanced MHTGRs, recognizing that the requirements for the steam cycle, gas turbine (direct- or indirect-cycle), and process heat reactor are unique. Topics include thermodynamic considerations, differing configurations, and construction types; materials (metals, composites, ceramics); germane technology bases; and advanced heat exchanger technologies.     

On the role of fusion neutron source with thorium blanket in forming the nuclide composition of the nuclear fuel cycle of the Russian Federation

The possible role of available thorium resources of the Russian Federation in utilization of thorium in the closed (U–Pu)-fuel cycle of nuclear power is considered. The efficiency of application of fusion neutron sources with thorium blanket for economical use of available thorium resources is demonstrated. The objective of this study is the search for a solution of such major tasks of nuclear power as reduction of the amount of front-end operations in the nuclear fuel cycle and enhancement of its protection against uncontrolled proliferation of fissile materials with the smallest possible alterations in the fuel cycle. The earlier results are analyzed, new information on the amount of thorium resources of the Russian Federation is used, and additional estimates are made. The following basic results obtained on the basis of the assumption of involving fusion reactors with Th-blanket in future nuclear power for generation of the light uranium fraction ^232+233+234U and ²³¹Pa are formulated. (1) The fuel cycle would shift from fissile ²³⁵U to ²³³U, which is more attractive for thermal power reactors. (2) The light uranium fraction is the most “protected” in the uranium fuel component, and being mixed with regenerated uranium, it would become reduced-enrichment uranium fuel, which would relieve the problem of nonproliferation of the fissile material. (3) The addition of ²³¹Pa into the fuel would stabilize its neutron-multiplying properties, thus making it possible to implement a long fuel residence time and, as a consequence, increase the export potential of the whole nuclear power technology. (4) The available thorium resource in the vicinity of Krasnoufimsk is sufficient for operation of the large-scale nuclear power industry of the Russian Federation with an electric power of 70 GW for more than one quarter of a century. The general conclusion is that involvement of a small number of fusion reactors with Th-blanket in the future nuclear power industry of the Russian Federation would to a large extent solve its problems and increase its export potential.     

氘氚聚变中子发生器旋转氚靶传热特性研究

强流氘氚中子发生器可用于模拟聚变堆中子环境, 对于开展聚变堆包层材料相关实验研究具有重要意义. 本文提出了一种用于10¹² n·^-1量级氘氚中子发生器HINEG (high intensity neutron generator)的旋转氚靶系统设计方案, 并对其技术难点和强化传热方法进行了介绍. 为考查该氚靶系统的传热特性, 利用Computational Fluid Dynamics方法对冷却水层厚度、冷却水流速和氚靶系统旋转速度对靶面冷却的影响进行了分析, 并对不同热功率密度下靶面的传热过程进行了研究. 结果显示, 大的水层厚度、大的冷却水流速和高的靶系统旋转速度有利于靶面的冷却, 但水层厚度和水流速的变化对靶面传热影响较小. 一定条件下靶面所承受的热功率密度不能超过某个限值.