核乳胶在激光直接驱动内爆DT燃料离子温度诊断中应用

在神光Ⅱ基频光直接驱动内爆实验中，采用国产核乳胶测量了DD反应产生的质子产额，根据DD反应的质子产额与DT反应的中子产额的比值，诊断了DT燃料离子温度；由于核乳胶对质子的探测效率比中子探测效率高，产额比值法在低产额特别是间接驱动实验条件下诊断燃料离子温度是一种较好的方法。     

激光直接驱动内爆中子产额实验诊断

利用激光驱动充 DT燃料的内爆靶丸 ,完成了“神光 ”激光装置首轮内爆出中子实验。通过超快猝灭塑料闪烁探测器测到了直接驱动内爆中子产额。中子产额 10 7～ 10 9,测量误差± 7%～± 10 %。中子产额实验值与理论部提供的计算值 (爆推靶 )在± 2 0 %范围内一致。     

辐射驱动低产额中子诊断数据处理

本文介绍了在“神光”装置上用塑料闪烁探测器测量辐射驱动内爆低产额中子的数据处理方法,将实验数据输入计算机模拟出了所测中子产额几率分布公式及曲线,对测量结果的可信号度进行了分析讨论。     

超快猝灭塑料闪烁探测器氘氚中子灵敏度标定

本文概要介绍了超快猝灭塑料闪烁探测器特性，并在不同闪烁体、光导和微通道板光电倍增管的组合条件下用１０ｎｓ脉宽的窄脉冲中子管对探测器的Ｄ－Ｔ中子灵敏度进行了标定。由这些标定数据推算出的探测器不同条件下的Ｄ－Ｔ中子灵敏度与实测数据在误差范围内是一致的。     

用BF3探测器阵列测量"神光Ⅱ"辐射驱动DD中子产额

利用激光辐射驱动充纯氘燃料的内爆靶丸,完成了"神光Ⅱ"激光装置辐射驱动内爆出中子实验.通过BF3探测器阵列测到了DD中子产额.中子产额103～105,测量误差±20%到±100%.实验结果表明燃料中加杂质后,中子产额明显下降.     

“神光Ⅲ原型”装置首轮实验中子产额诊断

利用激光辐射驱动充D-D燃料的内爆靶丸,完成了"神光Ⅲ原型"大型激光装置首轮出中子实验。通过塑料闪烁探测器测到了辐射驱动内爆中子产额。中子产额107~108,测量不确定度~10%。     

快电子对快离子损失诊断测量的影响

基于闪烁体原理的快离子损失探针(Fast Ion Loss Detector,FILD),可以同时测量损失快离子的能量和pitch-angle的值,是核聚变装置中对高能粒子诊断的重要方式。根据先进实验超导托卡马克(Experimental Advanced Superconducting Tokamak,EAST)的发展需求,为了更好地对损失快离子行为进行研究,设计并安装了快离子损失诊断,且探测到在中性束加热条件下产生的损失快离子。同时,探测到在放电中产生的逃逸电子,以及低杂波注入时快电子产生X射线对快离子损失背景信号的影响。并且在H-mode放电时边界扰动也对快离子损失信号产生影响,这些探测到的现象都为不断升级损失诊断系统提供依据。     

利用次级中子诊断燃料面密度

介绍了一种用于测量在低中子产额下的压缩燃料面密度诊断方法,并且这种方法在实验中得到了实现。它是利用塑料闪烁体探测器对辐射驱动充纯D的内爆靶所产生的初级中子和次级中子进行测量,在中子产额较低的情况下,实现了利用次级中子和初级中子的产额比值法来诊断燃料面密度〈ρR〉,并获得了实验数据。这个工作对我们以后开展燃料面密度的诊断奠定了基础。     

燃料试样堆内辐照温度设计与实验研究

为使燃料尽可能在最恶劣设计工况下进行辐照实验,开展基于高通量工程试验堆（HFETR）的燃料试样堆内辐照温度设计与实验研究。按照铀装量设计燃料试样在辐照装置内的位置,能够改善轴向燃料试样热流密度的不均匀性。HFETR主冷却剂低温状态下,在燃料试样外包覆液态铅铋合金和不锈钢能够实现燃料芯体及燃料包壳的高辐照温度指标。设计和实验结果表明,稳态和短期瞬态运行工况下,不锈钢盒表面辐照温度始终低于HFETR燃料元件包壳表面最高温度限值,满足反应堆运行和燃料辐照实验安全要求。为提高稳态运行工况下燃料试样的辐照温度,堆芯设计时应避免或降低由于反应性扰动造成的辐照装置内燃料试样短期瞬态功率影响,减小辐照孔道内燃料试样的热点因子。      

温度及pH敏感N-异丙基丙烯酰胺/β-环糊精水凝胶的辐射制备及其性能研究

采用顺丁烯二酸酐(MAH)对β-环糊精(β-CD)进行改性,合成了丁烯二酸单酯化β-环糊精(MAH-β-CD).以电子束为辐射源对 MAH-β-CD 和N-异丙基丙烯酰胺(NIPAAm)混合物水溶液进行辐照,制备了PObr(NIPAAm-co-MAH-β-CD)水凝胶.研究了辐照剂量对水凝胶溶胀性能的影响;同时研究了温度、pH值和离子强度等因素对水凝胶溶胀率的影响.结果表明,poly(NIPAAm-co-MAH-β-CD)水凝胶具有温度敏感性、pH敏感性和离子强度敏感性.     

Medium energy ion irradiation capability for studies of radiation damage effects over a wide temperature range

In this report, we present preliminary ion irradiation experiments performed using a new medium energy (up to ∼20 MeV), high temperature ion irradiation capability that we developed at Los Alamos National Laboratory. Details of ion fluence and irradiation temperature (including ion beam heating) control, measurements procedure and accuracy are described. In particular, we investigated irradiation-induced atomic intermixing in a layered structure composed of MgO and HfO₂ thin films deposited on a sapphire substrate. This multi-layered structure represents a dispersion nuclear fuel form surrogate. To simulate a nuclear reactor environment, we performed ion irradiation using 10 MeV Au ions to a fluence of 5 × 10¹⁵ cm⁻² at a substrate temperature of 1000 °C. The degree of atomic intermixing was assessed from depth profiles of Mg, Hf, and Al atoms, which were obtained using Rutherford backscattering spectrometry. We found considerable interlayer mixing for sample regions in close proximity to the sapphire substrate.     

高温气冷实验堆燃料元件双向探测器的研制

介绍了高温气冷实验堆燃料元件双向探测器的基本原理和实现方法。它以两个并联的感应线圈为敏感元件,通过双通道法采集信号,以８９Ｃ５１单片机为处理核心,系统软件采用循环扫描输入端口的方式获取过球信号,经智能分析、判断,实现了燃料元件的双向检测。     

Requirements for high temperature reactor fuel particle design assessment

In the framework of a large Research and Development programme devoted to High Temperature Reactors (HTR) and set up in the CEA from 2000 on, we will address ourselves to the issue of coated fuel performance and design. Although HTR fuel main features have been established for a long time, we need today to reassess the fuel design to make sure that it meets the requirements linked to the most recent projects of High Temperature Reactors. Thus, in collaboration with Framatome and in connection with the Gas Turbine - Modular Helium Reactor (GT-MHR) international project, we are planning to perform parametric thermal and mechanical studies, regarding different particle design options (kernel diameter, layers composition and thickness) and seeking optima concerning particle leak tightness and fission product retention. But to initiate such studies, we have first of all to define the design bases and the requirements for HTR fuel, in terms of kernel composition (fissile element, oxide stoechiometry, enrichment), particle and compact geometry (dimensions, particle volume fraction in the graphite matrix), power density, cooling gas temperature and irradiation conditions (burnup, fast fluence).     

Development of laser ion source for heavy ion applications

We have been developing a high-performance laser ion source (LIS) for practical applications since 2009. Ideally, the LIS should generate a carbon beam with a peak current of 20 mA and a pulse duration of over 1 μs. We selected a Nd:YAG laser with a Gaussian-coupled resonator as the laser source based on our experience of generating high-charge-state ion beams. This laser can produce fundamental pulses with a power of 650 mJ and durations of about 6 ns. The graphite target used is 10 cm high and 10 cm in diameter, as it can be irradiated with up to 10⁵ laser shots. The maximum extraction voltage was designed to be 50 kV. We have already finished designing the LIS and we commenced fabrication. We intend to measure the source performance by performing plasma and beam tests up to the end of March 2011.     

Use of the MCNP-polimi code for time-correlation safeguards measurements

Active nuclear safeguards measurements that rely on the time correlation between fast neutrons and gamma rays from the same fission are becoming a useful technique. In previous works we have shown the feasibility of this method, in conjunction with the use of the well-known MCNP simulation code and the use of artificial neural networks, to estimate the mass and enrichment of fissile samples enclosed in special, sealed containers.

In a more recent works, we pointed out some features of MCNP that represent a drawback in the simulation of correlation measurements. In fact, MCNP is not intended for obtaining second order moments. Therefore, to achieve an agreement between the simulations and the experiment, we resorted to the use of effective physical parameters (for example detection threshold and light output). Recently, by suitably modifying MCNP, we developed the MCNP-PoliMi code, which attempts to simulate the physics of each interacton more realistically.

In this paper, we present the results of the calibration of a plastic scintillator using a Cf-252 source, traditionally used in the above-mentioned nuclear safeguards experiments. We show that the physical parameters found by calibration and used in the MCNP-PoliMi simulations are reasonable for this type of detector, and that the correlation functions thereby obtained are in good agreement with the experiment.     

Anomalous transport driven by ion temperature gradient instability in an anisotropic deuterium-tritium plasma

In this work, the anomalous transport driven by the ion temperature gradient instability is investigated in an anisotropic deuterium-tritium (D-T) plasma. The anisotropic factor α, defined as the ratio of perpendicular temperature to parallel temperature, is introduced to describe the temperature anisotropy in the equilibrium distribution function. The linear dispersion relation in local kinetic limit is derived, and then numerically evaluated to study the dependence of mode frequency on the anisotropic factor α of D and the fraction of T particle ε_T by choosing three sets of typical parameters, denoted as the cyclone base case, ITER and CFETR cases. Based on the linear results, the mixing length model approximation is adopted to analyze the quasi-linear particle and energy fluxes for D and T. It is found that choosing small α and large εT is beneficial for the confinement of particle and energy for D and T. This work may be helpful for the estimation of turbulent transport level in the ITER and CFETR devices.     

HTR-10燃料元件双向探测器敏感元件特性研究

探讨了将感应线圈用作探测器敏感元件的优点,研究了串联感应线圈的结构参数和性能之间的关系,并进行了优化。实验结果表明,采用电感线圈作为敏感元件可以获得的检测信号,满足实际使用要求。     

The plume diagnostics of 30 cm ion thruster with an advanced plasma diagnostics system

In order to achieve a better understanding of plume characteristics of LIPS-300 ion thruster, the beam current density, ion energy and electron number density of LIPS-300 ion thruster plume are studied with an Advanced Plasma Diagnostics System(APDS) which allows for simultaneous in situ measurements of various properties characterizing ion thruster, such as plasma density, plasma potential, plasma temperature and ion beam current densities, ion energy distribution and so on. The results show that the beam current density distribution has a double‘wing' shape. The high energy ions were found in small scan angle, while low energy ions were found in greater scan angle. Electron number density has a similar shape with the beam current density distribution.