Event Priority Instrumentation System for Nuclear Experiments on Scientific Satellites

The number of information bits per unit time, or data rate, which can be telemetered back to earth from a scientific satellite is limited by restrictions on weight, volume and power. Thus, each experimenter (generally one of many) is allotted a very limited data rate capability. In nuclear experiments, where a wide variety of events may occur per unit time, use of this rate capability may be optimized by selection of events on a priority basis. Described here is an event priority instrumentation system developed for use in scientific satellites. The system allows for the selection of the highest priority event occurring during a telemetry sequence. Also, provision is made for periodically changing the order of priority. All circuitry was designed and developed to minimize weight, volume and power drain and to maintain stable characteristics while unattended for periods as long as one year. The operating temperature range is -20°C to 60°C.     

Cost-Effective Superconducting Magnet Design for Next-Step Fusion Experiments

It is widely believed that the use of superconducting magnets in next-step fusion experiments is driven only by the reactor relevance of low circulating power in a fusion plant. However, there is a broad range of fusion magnet applications in which the use of superconducting magnets in near-term experiments will reduce the capital cost of an experiment, along with further reductions in the operating cost. This claim extends to Proof-of-Principle and Proof-of-Performance experiments for Steady-State and Spherical Tori, Compact Stellarators, Spheromaks, and Heavy Ion Fusion Drivers.     

Study of Nuclear Physics for Nuclear Fusion

Based on the concept of damp matching [1] and the famous d + t fusion data, a conventional quantum mechanics calculation shows that the plasma fusion, muon-catalyzed fusion, and the low-energy nuclear reaction are essentially same in the sense of resonant tunneling through the Coulomb barrier. The good agreement between theory and experimental data justifies the selectivity in resonant tunneling, which implies the possibility of having fusion energy with no strong neutron and gamma radiation.     

Nuclear Analysis of Blanket/Shield Design for D-D Tokamak Fusion Reactor

A study is made of the nuclear characteristics of blanket/shield design intended for the D-D tokamak reactor incorporating a cooperative effort by the University of Illinois, Brookhaven National Laboratory and Lawrence Livermore Laboratory. The reactor is characterized by high value of plasma beta (β=0.3) and low value of neutron wall loading (W _n =0.436 MW/m²). The 1 m-thick blanket is composed mainly of graphite, and the 1 m-thick shield is a combination of B₄C, Al and H₂O. Multi-dimensional calculations are carried out to confirm the results of one-dimensional calculation and to assess the problems inherent in the design.

Compared to blankets constituted of other materials, the graphite blanket possesses the characteristics of much smaller residual radioactivity, afterheat and biological hazard potential, which could possibly more than offset the lower nuclear heating that can be provided. The design requirements for the magnet shield are satisfied by the present combination and thicknesses of blanket/shield materials.     

核聚变实验装置HT-7U一维及二维辐射防护设计研究

主要介绍一维、二维中子输运程序ANISN,DOT3.5在核聚变实验装置HT-7U辐射屏蔽物理设计中的应用。计算和分析了该装置实验大厅内外中子注量/能谱、γ注量/能谱、中子剂量率、γ剂量率的空间分布,对屏蔽材料的选取及屏蔽层厚度进行了优化设计,为HT-7U装置的辐射屏蔽物理设计提供了建议性意见及理论依据。     

核岛水过滤器滤芯性能鉴定试验研究设计和验证

核岛水过滤器是核电厂水质净化的重要设备,起到了去除腐蚀产物和固体颗粒物的作用。通过对国内外滤芯鉴定标准的研究,本文对自主研制的核岛水过滤器滤芯开展了主要性能鉴定试验研究设计,搭建了滤芯鉴定试验台架,成功测试了滤芯的主要性能参数,滤芯各项测试性能参数能够满足核电厂核岛系统运行要求。     

基于FPGA的数字核脉冲高速传输系统设计

针对高速数字核脉冲采集中的实时传输问题,提出了一种基于FPGA和USB的传输结构。该结构采用现场可编程逻辑阵列(FPGA)作为核心控制器,并通过乒乓操作原理对高速核脉冲进行采集,定义特定的简单可靠的传输帧结构。利用USB与PC机通信,既实现了高速数据的实时传输又真正实现了"即插即用",提高了整套系统的实用性。实验测试验证了该系统的高效性。     

脉宽调制器单粒子效应测试系统研制

本文在分析脉宽调制器(PWM)单粒子效应主要失效模式的基础上,研制了具备频率异常测试、占空比异常测试和参考电压测试功能的PWM单粒子效应测试系统,并在中国原子能科学研究院HI-13串列加速器上开展了单粒子效应试验。试验结果表明:单粒子效应会导致PWM输出信号的脉冲丢失和占空比改变,脉冲丢失时间和占空比改变的持续时间有时可达数ms;UC1825AJ型PWM的单粒子效应LET阈值约为4.4MeV·cm2·mg-1,UC1845AJ型PWM的抗单粒子性能受工艺批次的影响较大。     

一种仿252Cf中子源随机脉冲信号参数检测系统的FPGA设计与实现

从252Cf自发裂变中子源之裂变中子在时间分布上相互独立的基本原理出发,针对随机核信号在时间上呈泊松分布,在幅度上服从高斯分布这一特征,开展了基于FPGA技术的仿252Cf中子源随机核信号产生及其脉冲参数的检测研究。研究结果表明,仿252Cf中子源随机核脉冲参数检测系统,在脉冲上升沿或下降沿到达后的第一个时钟周期,便能开始输出检测结果,满足了随机脉冲参数检测的实时性要求。通过观察LabVIEW GUI上显示的参数检测结果,与核脉冲的计数率、幅度统计特性、时间间隔统计特性基本相吻合,表明基于FPGA的仿252Cf源的核信号参数检测系统是切实可行的。     

船用核反应堆概率安全评价的初始事件分析

根据船用核反应堆的特点,对概率安全评价的初始事件分析方法进行了全面研究,提出了初始事件的分组原则及分组方法,给出了初始事件频率评估的量化模型。     

核脉冲微分峰位检测电路的研究

高性能峰位检测电路是峰值保持器的关键.从电路传递函数出发,分析了准高斯核脉冲经CR微分电路后波形表达式和幅度变化,讨论了核脉冲峰位与微分过零点的关系,并用MATLAB软件进行了数值计算.结果表明,无源CR微分电路不能准确地测出核脉冲峰位,电路灵敏度低、通频带窄;有源CR微分峰位检测电路可以准确地测出核脉冲的峰位,灵敏度高、通频带宽.最后介绍了基于有源CR微分峰位检测电路煤矸石能谱仪峰值保持器的设计.     

Design and Seismic Analysis of the Large Biological Shielding Door in Nuclear/Fusion Reactor

The large biological shielding door is the important protective equipment of nuclear/fusion reactor. Considering the seismic load and the gravity, it is designed. Based on the modal theory, the modal analysis is performed to obtain the natural frequency and the vibration modes of the door. Using the response spectrum method, the seismic analysis is performed to obtain the stress and displacement. Results show that the biological shielding door can meet the requirement of ASME and the design is reasonable and feasible; the horizontal acceleration being perpendicular to the door leaf is the major factor for the design of the door.     

CFBR-Ⅱ堆脉冲产额超额定值事件概率浅析

简介了CFBR-Ⅱ堆结构、运行机理、固有安全性特点,列举了CFBR-Ⅱ堆可能发生的事故/事件类型.采用概率安全评价方法,计算了CFBR-Ⅱ堆脉冲产额超额定值事件发生概率,完成了底事件重要度的分析.     

用于核反应测量的脉冲波形数字甄别系统设计方案

针对核物理实验对核反应测量脉冲波形甄别系统的性能要求,提出了基于多片高速A/D和高端FPGA的数字化脉冲波形甄别系统设计方案。高速A/D完成对探测器输出波形信号的数字化,而后通过可编程的方式在FPGA内部采用先进的数字信号处理算法完成对信号的甄别,可以解决模拟电子线路对超大信号难以处理的问题,进而对探测器输出不同粒子特征进行准确提取,实现准确实时地触发高速数据采集主板系统。     

北京核电站模拟器硬件的功能和特点

本文介绍北京核电站模拟器硬件构成并分析其功能和特点。     

气凝胶的制备及其在惯性约束聚变实验中的应用

气凝胶是惯性约束聚变(ICF)实验中的一种理想的靶材料.文章介绍SiO2气凝胶、有机和碳气凝胶、二元气凝胶、掺杂SiO2气凝胶和其它几种气凝胶的研制,探讨了气凝胶在ICF相关研究领域的应用.     

Versatile Logic System for Use in Nuclear Experiments on Scientific Satellites

An improved fast low-power-drain logic system has been developed for use in nuclear experiments on scientific satellites. The basic unit of the system is an AND-NAND gate which has a response in the 10 nanosecond range, a power drain of 2.0 milliwatts and operates over the temperature range of -40°C to +80°C. In addition to providing the AND-NAND logic functions, one or more of the basic units may be connected to yield the following: a. monostable pulse generator, b. pulse generator yielding an output pulse at the leading edge of the input pulse, c. Delay, d. Threshold Detector, and e. Bistable Circuit. The system requires relatively simple circuitry for interfacing at its outputs and inputs.     

A Fusion Nuclear Science Facility for a fast-track path to DEMO

An accelerated fusion energy development program, a “fast-track” approach, requires proceeding with a nuclear and materials testing program in parallel with research on burning plasmas, ITER. A Fusion Nuclear Science Facility (FNSF) would address many of the key issues that need to be addressed prior to DEMO, including breeding tritium and completing the fuel cycle, qualifying nuclear materials for high fluence, developing suitable materials for the plasma-boundary interface, and demonstrating power extraction. The Advanced Tokamak (AT) is a strong candidate for an FNSF as a consequence of its mature physics base, capability to address the key issues, and the direct relevance to an attractive target power plant. The standard aspect ratio provides space for a solenoid, assuring robust plasma current initiation, and for an inboard blanket, assuring robust tritium breeding ratio (TBR) >1 for FNSF tritium self-sufficiency and building of inventory needed to start up DEMO. An example design point gives a moderate sized Cu-coil device with R/a = 2.7 m/0.77 m, κ = 2.3, B_T = 5.4 T, I_P = 6.6 MA, β_N = 2.75, P_fus = 127 MW. The modest bootstrap fraction of ƒ_BS = 0.55 provides an opportunity to develop steady state with sufficient current drive for adequate control. Proceeding with a FNSF in parallel with ITER provides a strong basis to begin construction of DEMO upon the achievement of Q ∼ 10 in ITER.     

核辐射脉冲幅度分析的基线自适应Kalman滤波估计

为实现核辐射脉冲幅度分析中的基线估计,该文探讨了一种用自适应Kalman滤波方法对基线进行估计的方法。通过对核辐射脉冲信号波形物理特性的分析,结合自适应Kalman滤波算法,对核辐射信号基线进行数学建模,进而实现基线估计。实验结果证明了该方法的有效性,能为脉冲数字成形等后续工作提供很好的预处理数据。