多方向加权方法在D-T聚变中子能谱测量中的应用

中子能谱是研究和诊断核反应过程特性最重要的特征量之一。建立了一种新的多方向加权方法用于D-T聚变中子能谱测量:在反冲质子出射方向的多个不同角度上,同时布置探测器,最终的中子能谱由各方向所获取的反冲质子能谱结合相应的权重值确定。Geant4模拟结果显示,多方向加权方法可以提升探测效率和求解结果精度。利用多方向加权方法对高斯分布中子源以及实际的D-T聚变中子能谱进行测量模拟与求解分析,分析结果验证了该方法的可行性和有效性。     

用伴随粒子法测量加速器聚变中子注量率

用伴随粒子法测量加速器聚变中子注量率。采用金硅面垒半导体探测器测量α粒子。对靶室设计、氘束束流、氚靶等提出了技术要求。重点介绍了得到最佳α粒子能谱的方法。对测量中重要的修正因子也尽可能作详细介绍。给出了测量数据处理和计算的公式或方     

用伴随粒子法测量加速器聚变中子注量率

用伴随粒子法测量加速器聚变中子注量率。采用金硅面垒半导体探测器测量α粒子。对靶室设计、氘束束流、氚靶等提出了技术要求。重点介绍了得到最佳α粒子能谱的方法。对测量中重要的修正因子也尽可能作详细介绍。给出了测量数据处理和计算的公式或方法。指出目前达到的测量误差在1％～1.5％。     

中子能谱测量中的本底测定及计数损失分析

分析了中子能谱测量中的本底测定技术,实验测量了DT源中子能谱、源本底中子能谱和样品本底中子能谱,在不同线性门设置、主放大器成形时间常数下测量了线性门信号输入输出比,通过选择在分辨谱谷底附近不同位置的单道阈值,测量了由DT源中子产生的反冲质子谱,测量了不同能量范围的中子、伽玛分辨二维谱,对BC501A液体闪烁体探测器信号计数损失的相关因素进行了分析,提出了几种减少计数损失的方法,结果可供中子能谱测量相关实验研究参考。     

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。     

英稳步推进聚变能发展战略的实施

<正>英国已选定“用于能源生产的球形托卡马克”（STEP）原型聚变电厂的建设厂址，并宣布将与相关技术开发商合作在卡勒姆园区建设三座聚变设施：英国托卡马克能源公司紧凑球形托卡马克原型堆ST80-HTS、英国第一光聚变公司弹丸聚变研究装置Machine 4和加拿大通用聚变公司（General Fusion）“磁化靶”原型聚变电厂。这意味着英在推进聚变能发展战略实施方面取得显著进展。     

贫化铀、贫化铀/氢化锂组合装置的泄漏中子能谱

建立了贫化铀和氢化锂球壳的聚变裂变混合能源堆的包层模拟装置.在PD300氘氚中子发生器直流运行模式下,用BC501A液体闪烁体探测器在0 °方向测量贫化铀和贫化铀/氢化锂球壳组合装置的DT中子轰击下的泄漏中子能谱(0.75-16 MeV),并用MCNP5程序和ENDF/B-VI数据库对装置进行模拟计算其泄漏中子能谱,两...     

冷聚变实验探索

采用电解法和氘气吸附法研究了冷聚变现象。在一次电解实验中,电解开始后约90h,长中子计算器和液体闪烁中子计数器中都同时观察到一个持续时间达4h、峰值强度为400聚变/s的中子讯号。长中子计数器和液体闪烁计数器的计数均比本底高15倍,液体闪烁计数器同时记录了2.45MeV中子的反冲质子能谱。     

用大角度伴随粒子法测量聚变中子产额及其校对实验

描述了用大角度（178.2°）伴随α粒子方法测量绝对D-T 聚变中子产额及其校对实验。为此,设计和加工了一套三叉管校对靶室,α粒子探测器分别置于与D∧ 束成90°、135°和178.2°的方向上,测量和比较了三个方向的α粒子谱和绝对中子产额。分析了实验误差来源,并对实验结果进行了讨论。     

基于金活化片的单球谱仪研制及能谱测量

中国先进研究堆(CARR)H-8水平孔道是提供中子的实验孔道,可以提供稳定的辐射场,对于不同的中子实验,其所需的中子能谱谱形不同,准确测量中子能谱具有重要意义。为测量H-8水平孔道中子能谱,研制一种以金活化片为热中子探测器的被动式单球中子能谱仪,使用MCNP程序对10^-11～15 MeV能区的中子能量响应进行计算,并分析能量响应的合理性。在CARR堆导管大厅对单球谱仪进行测试实验,使用高纯锗探测器测量各金活化片活度,使用UGA(unfolding based on genetic algorithm)解谱程序对实验数据进行解谱计算。结果表明,导管大厅出射中子能量在10^-9～10^-6 MeV范围内,单球中子谱仪可以较为精确的给出中子能谱数据,适用于CARR堆H-8水平孔道中子能谱测量研究。     

Behavior of the Pb–Li alloy impurities by ICP-MS

The ITER and DEMO projects are developing new test blanket modules (TBM), such as HCLL where the Li–Pb alloy plays a key role in the new commercial fusion reactors functionality. Lithium–lead eutectic alloy has no known uses outside of fusion technology, so the available databases of this material are currently incomplete. It is very important, within the material specifications, to have a complete characterization in order to define their chemical and physical properties, because any variation in the alloy composition has significant consequences in their behavior, and therefore in their regenerative function inside the blanket.This report provides a procedure to perform a wide material characterization, assessing the concentrations of major elements, as well as a review of trace level impurities that can be found both in the eutectic alloy as in starting materials. In this determination inductively coupled plasma mass spectrometry (ICP-MS) technique plays an important role, because as a highly sensitive technique it allows very low detection limits.     

Effects of kinetic profiles on neutron wall loading distribution in CFETR

The China Fusion Engineering Test Reactor (CFETR) is under design,which aims to bridge the gaps between ITER and the future fusion power plant.The neutron wall loading (NWL) depends on the neutron source distribution,which depends on the density and temperature profiles.In this paper,we calculate the NWL of CFETR and study the effects of density and temperature profiles on the NWL distribution along the first wall.Our calculations show that for a 200 MW fusion power,the maximum NWL is at the outer midplane and the vaule is about 0.4 MW m-2.The density and temperature profiles have little effect on the NWL distribution.The value of NWL is determined by the total fusion power.     

中国环流器二号A装置工程与实验进展

介绍了中国环流器二号A(简称HL-2A)装置上关键聚变工程技术取得的新进展及在磁约束聚变科学若干关键课题研究取得的重要实验成果,特别是在HL-2A装置上成功实现了偏滤器位形下具有边缘局域模的高约束模式运行,是我国磁约束聚变实验研究史上具有里程碑意义的重大进展,使我国的磁约束聚变科学和等离子体物理实验研究进入了一个崭新的阶段。     

基于最小化发电成本的聚变驱动次临界堆参数优化分析

利用自主发展的聚变驱动次临界堆 (FDS)系统分析软件SYSCODE ,通过遗传算法求解以最小化发电成本为目标函数 ,以聚变功率、中子壁负载、安全因子和包层平均热功率密度限等为约束条件的最优化模型 ,得到FDS的包层能量增益因子 (Qb) ,等离子体位形参数 :环径比 (A)、拉长比 (κ)和三角变形因子 (δ) ,工程与物理参数 :规一化比压 (βN)、轴上纵场 (BT)与等离子体电流 (IP)等的最优化设计 ,并详细分析了发电成本对最优设计点的敏感性。分析分两种情况 :一是聚变功率为定值 (设为 1 5 0MW ) ;二是包层平均热功率密度为定值 (分别设为 1 5、5 0、1 0 0和 5 0 0MW /m3)。     

基于GDT的14MeV中子源初步设计研究

为满足聚变材料测试对D-T聚变中子源的需要,本文首先根据国际上对用于聚变材料测试的中子源的要求给出设计目标,然后基于Gas Dynamic Trap(GDT)装置的实验进展,提出了基于GDT装置的14MeV中子源的设计初步方案,并建立了GDT中子源的物理模型。计算分析给出了两套中子源参数初步方案,其中FDS-GDT2中子壁负载为2MW/m2,可用于聚变材料的测试。     

工业CT技术特点及应用实例

概述了工业CT技术的主要特点及其在无损检测中的应用,介绍了工业CT在缺陷检测、焊缝质量诊断、密度分布表征、结构分析及装配质量检测等方面的应用实例.     

Investigating Neutronic Parameters of a Thorium Fusion Breeder with Recurrent Neural Networks

Artificial neural networks (ANNs) have recently been introduced to the nuclear engineering applications as a fast and flexible vehicle to modeling, simulation and optimization. In this paper, a new approach based on recurrent neural networks (RNNs) was presented for the neutronic parameters of a thorium fusion breeder. The results of the RNNs implemented for the tritium breeding ratio computation, energy multiplication factor and net ²³³U production in a thorium fusion breeder and the results available in the literature obtained by using Scale 4.3 were compared. The drawn conclusions confirmed that the proposed RNNs could provide an accurate computation of the tritium breeding ratio computation, the energy multiplication factor and the net ²³³U production of the thorium fusion breeder.     

Deuteron tunneling at electron-volt energies

We speculate on a new mechanism for deuteron-deuteron fusion reactions at electron-volt energies. Appealing to conservation principles, it is shown that deuteron tunneling leading to fusion is very unlikely to take place between two isolated deuterons. It is argued that in solids, however, tunneling may lead to fusion via a new reaction mechanism which populates energy levels of⁴He, with simultaneous energy transfer to an electron. Predictions of this theory are that d+d+e^– fusion at electron-volt energies in solids should lead to copious production of tritium, protium, energetic electrons, and small quantities of⁴He.     

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.     

Fusion Safety Research and Development in JAERI

This paper describes the current status and future plans of the fusion safety research and development regarding to the developments of the dust removal system and safety analysis code and the thermofluid experiments in the Japan Atomic Energy Research Institute (JAERI) for a fusion experimental reactor. The containment of the radioactive material is the key to achieve fusion safety. In the event of accidents, the source terms need to be evaluated with sufficient accuracy. Therefore, in JAERI, the dust characterization have been investigated and the dust removal system using electric force has been developed and tested. A safety analysis code including both thermal and plasma transient analyses under the various event sequences has been developed. Moreover, the preliminary experiments of thermofluid transients in the vacuum vessel such as Ingress of Coolant Event (ICE) and Loss of Vacuum Event (LOVA) have been started and the experimental results using preliminary LOVA/ICE apparatus during 1995–1996 are summarized in this paper.