聚变发电反应堆概念设计研究

在广泛分析聚变能相关领域研究发展状况和国际热核聚变实验堆(ITER)物理与技术基础上,提出了一个考虑了技术可行性的聚变发电反应堆概念(称之为FDS Ⅱ)。这个概念具有ITER参数适量外推的等离子体物理与技术水平的聚变堆芯和具有发展潜力的液态锂铅氚增殖包层,在对这个概念进行中子学、热工水力学、力学、安全与环境影响和经济学等一系列计算分析的基础上,给出了初步的概念设计和进一步设计优化的共性原则。     

具有双冷液态锂铅包层的聚变动力电站经济性初步分析

利用聚变系统分析软件SYSCODE对具有双冷液态锂铅包层的聚变动力电站(FDS-Ⅱ电站)经济性进行了计算和分析。采用包层材料预期价格,对成本进行了计算,同时分析了成本与工程参数及包层材料价格不确定性因子的关系,为进一步改进FDS-Ⅱ设计提供参考。     

聚变发电反应堆双冷液态锂铅包层氚增殖中子学分析研究

针对聚变发电反应堆(FDS Ⅱ)双冷液态锂铅(DLL)包层进行了中子学设计与分析,设计主要的原则是满足聚变堆的氚自持,并在此基础上,分析计算DLL包层核热分布。中子学一维优化分析使用的程序是自主开发的多功能中子输运/燃耗/优化程序VisualBUS1.0以及相应的数据库HENDL1.0/MG。基于二维模型进行校核计算所使用的程序为MCNP4C,相应的数据库为FENDL 2/MC。     

W/Cu和W/C涂层的循环热负荷实验

用等离子体喷涂和热压方法制作了W /Cu梯度功能材料和W /C涂层 ,其中W/C涂层具有多层的钨 (W )、铼 (Re)扩散阻挡势垒。为了试验这些复合材料能否经受聚变等离子体破裂时的高热负荷 ,用大功率ND :YAG激光进行了模拟实验。结果表明 :在 1 0 0～ 4 0 0MW /m2 的瞬时 (脉冲宽度为 4ms)热负荷作用下 ,经过 2 0 0～ 70 0次热循环 ,未发现W /Cu复合体的开裂。其中在 1 2 3MW /m2 的功率密度下作用70 0次后 ,发现等离子体喷涂试样表面的再结晶现象和严重的晶界腐蚀 ,由于激光的冷效应 ,晶粒生长的趋势并不明显 ,再结晶层的晶粒呈垂直于表面的柱状结构。W/C试样的退火实验表明 ,钨涂层的再结晶温度稍高于 1 4 0 0℃。在更高的功率密度下 (3 98MW /m2 )出现了明显的腐蚀坑 ,坑内呈疏松的蜂窝结构 ,坑的边缘形成了沉积区 ,能谱分析表明沉积区集聚了大量的金属杂质。等离子体喷涂试样比热压试样更易产生晶界的断裂和裂纹。在同等的热负荷条件下 ,W /CuFGM的质量损失低于石墨材料     

基于GDT的聚变裂变混合堆堆芯参数初步设计研究

基于Gas Dynamic Trap(GDT)装置的实验进展,提出了用于驱动聚变裂变混合堆包层的聚变堆芯参数设计。基于零维堆芯物理模型,计算分析给出了一套聚变功率为50MW的初步堆芯参数方案。利用GDT装置的实验结果对该物理模型进行计算对比校验,显示该物理模型和设计参数的可靠性。     

聚变裂变混合堆燃耗计算及燃料成本分析

基于轻水冷却的压力管式混合堆,采用压水堆卸载的乏燃料以及天然铀氧化物陶瓷燃料,建立混合堆包层的换料方案,详细计算了包层中子学性能随燃耗的变化情况,计算结果表明,包层在维持3000 MW热功率输出的同时,可以保证氚自持(氚增殖比TBR>1.20),而每5 a仅需向包层添加80 t左右的重金属燃料。基于建立的平衡循环计算了包层采用不同燃料时的单位发电燃料成本。结果表明,采用乏燃料和天然铀时的单位发电燃料成本分别为1.82×10-3、1.35×10-3$/(k W·h)。     

聚变发电反应堆双冷液态锂铅包层模块结构设计与分析

给出聚变发电反应堆FDS Ⅱ模块式液态锂铅包层(DLL)结构方案,以低活化马氏体(RAFM)钢为结构材料,采用液态金属LiPb作为增殖材料和冷却剂,使用碳化硅流道插件作为电绝缘和热绝缘。包层的设计特点体现在:从增殖区、冷却剂流道、屏蔽包层、母管、机械连接、维修装配等几个方面全局考虑包层设计,结构布置完整;独有的“”形隔板设计使氦气冷却回路容易实现,增殖流道简单,可简化制造工艺,提高可靠性。同其他液态锂铅包层相比,DLL包层在冷却剂系统、制造、装配上可成就较高的可行性。     

聚变发电反应堆双冷锂铅包层热工水力学设计与分析

依据结构设计和中子学计算结果给出了聚变发电反应堆FDS-Ⅱ双冷锂铅(DLL)包层热工水力学设计方案。采用数值计算软件对液态金属增殖区LiPb流场和第一壁热-结构等进行了模拟,并对功率转换系统的热效率进行了计算。通过分析评估,证实该包层热工水力学方案能较好地实现FDS-Ⅱ聚变发电反应堆预期目标。     

聚变驱动次临界堆经济性分析

利用自主开发的聚变系统分析软件SYSCODE对聚变驱动次临界堆的经济性进行了计算和分析。首先,对典型的环径比(标准环径比)设计方案,从堆芯几何参数、物理及工程参数等两个方面分析它们与成本的关系,然后,详细分析低、标准、高环径比三套候选设计方案的经济性与中子学参数的关系。研究发现,其经济性主要取决于包层中子学参数,另外,其经济性与几何、物理及工程参数的关系在一定条件下有别于纯聚变系统。     

托卡马克聚变中子源的数值模型研究

托卡马克(Tokamak)聚变装置中子学分析中,聚变中子源描述是重要的输入参数,其准确性直接影响分析结果的可靠性。通过分析ITER和欧洲聚变示范堆(EU DEMO)中子学分析中所采用的聚变中子源模型,提出了一种完整描述Tokamak中L-mode、H-mode等离子体的D-D、D-T聚变中子源的数值模型。在中国聚变工程实验堆(CFETR)的工程集成设计平台上,编写了基于蒙特卡罗算法的程序SCG求解该数值模型,实现了读取(零维)等离子体参数、输出可供典型中子学软件MCNP直接读取的中子源定义文件的功能。以CFETR氦冷球床包层的中子学分析模型为基准,在相同的L-mode等离子体D-T聚变工况下,相较于采用EU DEMO源子程序,采用本模型计算得到的中子壁负载差异最大值为2.02%,包层氚增殖率差异为0.18%,全堆能量增益因子的差异为0.23%。结果表明,本模型与其他源描述的差异较小,可应用于CFETR的中子学分析。     

Application of Numerical Simulation in the Design of HECLIC Blanket for CFETR

China Fusion Engineering Test Reactor is a new tokamak device which is proposed by China National Integration Design Group. The fusion power is 50–200 MW and its plasma major radius and plasma minor radius are 5.7 and 1.6 m. The helium cooled lithium ceramic (HECLIC) blanket, as a key component of the tokamak, has the basic function to provide tritium breeding and plasma limiter. The blanket also provides main thermal and nuclear shielding of the vacuum vessel and ex-vessel components such as magnetic coils during plasma operations. With the development of the numerical simulation technology, more and more design parameters can be obtained by this method. Numerical simulation has been used for design and optimization, because some parameters are very hard to obtain though theoretical calculation. In this study, the simulation methods are investigated for HECLIC blanket design. Besides, design flow of the blanket is discussed and related analysis is also introduced to improve the design.     

Conceptual design study of fusion DEMO plant at SWIP

The basic definition and development strategy of the DEMO plant based on the Chinese fusion power plant (FPP) program are presented briefly. A conceptual design study of fusion HCSB-DEMO reactor with a fusion power of 2550 MW and a neutron wall loading of 2.3 MW/m² is performed recently. Three sets parameters of core plasma for different DEMO design objectives are proposed. A helium-cooled blanket system with ceramic breeder (Li₄SiO₄), the structure material of low-activation ferritic steel (LAF/M) and Be neutron multiplier based on Chinese ITER HCSB-TBM design foundation are considered. The design parameters, preliminary analyses and the basic structure as well as development strategy of HCSB-DEMO reactor are introduced.     

Thermal hydraulics and mechnical design of the blanket for the Tokamak conceptual reactor UWMAK-II

A conceptual blanket design for UWMAK-II based on breeding in LiAlO₂ and helium cooling for a D-T fusion reactor is described. The reactor is a Tokamak with 316 stainless steel as the primary structural material, a major radius of 13 m and a minor radius of 5 m. The power output is 5000 MW(th) and the maximum temperature in the stainless steel structure is 650°C. This reactor design study is one of a series performed to evaluate the merits of various fusion reactor design concepts. In this paper the mechanical and the thermal hydraulics problem associated with the blanket for this reactor is described. Special attention has been given to the need for repairing and replacing the first wall of the blanket. Other problems which may arise from such a blanket design are also discussed.     

Thermal-hydraulic design of water-cooled pressure tube blanket for a fusion driven subcritical reactor

A Water-cooled Pressure Tube Energy production blanket (WPTE) for fusion driven subcritical reactor has been designed to achieve 3000 MW thermal power with self-sustaining tritium cycle. Pressurized water has great advantages in energy production; however the high pressure may cause some severe structural design issues. This paper proposes a new concept of water-cooled blanket. To solve the problem of the high pressure of the coolant, the pressure tube was adopted in the design and in the meantime, the thickness of the first wall can be significantly reduced as result of adopting pressure tube. The numerically simulating and calculating of temperature, stress distribution and flow analyses were carried out and the feasibility of using water as coolant was discussed. The results demonstrated the engineering feasibility of the water-cooled fusion–fission hybrid reactor blanket module.     

Modeling and multi-pipe manifolds optimization of the WCCB blanket sector for CFETR

In this paper, one standard water cooled ceramic breeder blanket sector has been modeled for the Chinese fusion engineering test reactor using RELAP5/MOD3.3 with details of anisotropic structures, positions and nuclear heat of the blanket modules. The multi-pipe manifolds of the current sector design scheme has been designed and analyzed. And an optimized scheme was proposed to further reduce the pressure drop, uniform the flow distribution, and prevent overheating. Also the fusion power excursion transients were simulated to evaluate the system heat removal and recovery ability. The results indicated that high-transient heat flux up to 0.8 MW/m2 can cause sub-cooled boiling of the coolant in the first wall area of certain modules. Coolant returns to single phase soon after the end of the transient. According to the analysis, it is suggested that the blanket modules surrounding plasma have as similar structure design features as possible and sizes of the modules should be kept relatively small so as to obtain a reasonable pressure drop.     

The UWMAK-II study: A conceptual design of a helium cooled, solid breeder, Tokamak fusion reactor system

UWMAK-II is a conceptual design study of a low ß, circular Tokamak fusion power reactor. The aim of the study has been to perform a self-consistent analysis of a probable future fusion power system based on the philosophy that design decisions, wherever possible, should be conservative and should be based on present technology. As such, this system will not be the smallest, the least expensive, or the optimum Tokamak reactor. Rather, it represents a feasible system which we use to assess the technological problems uncovered and to examine possible solutions. The plasma is designed to generate 5000 MW(th) during a pulse and 1709 MW(e) continuously based upon a burn cycle with a 90 min burn and a 6.5 min rejuvenation period. The plasma carries a current of 14.9 MA and is designed with a double null poloidal divertor for impurity control and particle pumping. In addition, a low Z liner in the form of a carbon curtain is included to eliminate any source of high Z impurities. Plasma heating to ignition involves the use of neutral beam heating for a 10 sec period during which 200 MW of 500 keV deuterium atoms are injected into the plasma.The blanket design employs helium cooling and the solid lithium-bearing compound, lithium aluminate (Li₂Al₂O₄) for breeding tritium. The structural material is 316 stainless steel and beryllium is used as a neutron multiplier. The neutron radiation environment produces radiation damage that considerably influences blanket and system performance. The most significant effect is the loss of ductility which appears to limit the usable lifetime of the blanket first wall to about 2 yr at a 14 MeV neutron wall loading of 1.16 MW/m². The solid breeder blanket minimizes the tritium inventory but because of the low fractional burnup in the plasma and the need for roughly a one day reserve of fuel, the inventory is 17.7 kg. Induced radioactivity levels in the structure are of the order of 1 Ci/W(th) at shutdown after two years of operation. The main contributors to the activity are ) and ). Afterheat levels are slightly above 1% of thermal power but the afterheat power density is low, less than 0.1 w/g. The power cycle involves a He---Na intermediate heat exchanger followed by a sodium—steam system. The sodium intermediary is used to minimize tritium leakage through the power cycle and to provide a working fluid for thermal energy storage such that continuous electrical output is produced despite a pulse plasma cycle. A materials resource study has been completed for a UWMAK-II type system and beryllium appears to present a particular problem with regard to adequate resources. Other materials that could present problems of procurement include chromium and nickel. A preliminary economic analysis has been carried out to identify major cost areas and this is described.     

D-T experiments on TFTR

Temperatures, densities and confinement of deuterium plasmas confined in tokamaks have been achieved within the last decade that are approaching those required for a D-T reactor. As a result, the unique phenomena present in a D-T reactor plasma (D-T plasma confinement, alpha confinement, alpha heating and possible alpha driven instabilities) can now be studied in the laboratory. Recent experiments on the Tokamak Fusion Test Reactor (TFTR) have been the first magnetic fusion experiments to study plasmas with reactor fuel concentrations of tritium. The injection of 20 MW of tritium and 14 MW of deuterium neutral beams into the TFTR produced a plasma with a T/D density ratio of 1 and yielded a maximum fusion power of 9.2 MW. The fusion power density in the core of the plasma was 1.8 MW m^–3 approximating that expected in a D-T fusion reactor. In other experiments TFTR has produced 6.4 MJ of fusion energy in one pulse satisfying the original 1976 goal of producing 1 to 10 MJ of fusion energy per pulse. A TFTR plasma with T/D density ratio of 1 was found to have 20% higher energy confinement time than a comparable D plasma, indicating a confinement scaling with average ion mass, A, of _E. The core ion temperature increased from 30 keV to 37 keV due to a 35% improvement of ion thermal conductivity. Using the electron thermal conductivity from a comparable deuterium plasma, about 50% of the electron temperature increase from 9 keV to 10.6 keV can be attributed to electron heating by the alpha particles. At fusion power levels of 7.5 MW, fluctuations at the Toroidal Alfvén Eigenmode frequency were observed by the fluctuation diagnostics. However, no additional alpha loss due to the fluctuations was observed. These D-T experiments will continue over a broader range of parameters and higher power levels.Work supported by U.S. Department of Energy Contract No. DE-AC02-76-CHO-3073.     

Updated neutronics analyses of a water cooled ceramic breeder blanket for the CFETR

The water cooled ceramic breeder (WCCB) blanket employing pressurized water as a coolant is one of the breeding blanket candidates for the China Fusion Engineering Test Reactor (CFETR).Some updating of neutronics analyses was needed,because there were changes in the neutronics performance of the blanket as several significant modifications and improvements have been adopted for the WCCB blanket,including the optimization of radial build-up and customized structure for each blanket module.A 22.5 degree toroidal symmetrical torus sector 3D neutronics model containing the updated design of the WCCB blanket modules was developed for the neutronics analyses.The tritium breeding capability,nuclear heating power,radiation damage,and decay heat were calculated by the MCNP and FISPACT code.The results show that the packing factor and 6Li enrichment of the breeder should both be no less than 0.8 to ensure tritium self-sufficiency.The nuclear heating power of the blanket under 200 MW fusion power reaches 201.23 MW.The displacement per atom per full power year (FPY) of the plasma-facing component and first wall reach 0.90 and 2.60,respectively.The peak H production rate reaches 150.79 appm/FPY and the peak He production reaches 29.09 appm/FPY in blanket module # 3.The total decay heat of the blanket modules is 2.64 MW at 1 s after shutdown and the average decay heat density can reach 11.09 kW m-3 at that time.The decay heat density of the blanket modules slowly decreases to lower than 10 W m-3 in more than ten years.