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《中国原子能科学研究院年报》2019,(0)
<正>针对生产工艺特定时期内产生的废物中钚的总量,开展了NDA实验研究。主要包括涉及中子测量的实验装置改进设计和涉及钚同位素测量的γ能谱测量实验条件选择,后者包括标准样品测量。1)中子测量装置的改进设计根据测量对象,完成了中子测量装置的改进设计,以便于进行含钚废物的有源测量分析。中子测量分为无源中子测量和有源中子测量两种模 相似文献
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《核技术》2018,(12)
以辐射场全能段中子能谱获取及周围剂量当量转换为目的,针对一套以3He正比计数器为探测器的多球中子谱仪,介绍了采用脉冲幅度分析法进行中子-γ甄别,准确测量中子计数率的方法;测量并获取了实验室本底环境中子、Am-Be中子源、氘氘中子管连续出射中子三种辐射场的中子能谱,并予以分析;基于中子能谱进行周围剂量当量转换,分析了不同能量段中子所占的剂量比重,发现快中子是主要贡献者;在比较测量中,对三种单慢化体中子剂量仪器产生的误差进行了理论分析,并给出了依靠多球中子谱仪测准中子周围剂量当量的三点建议。多球中子谱仪可以直接测算周围剂量当量,可以指导其它中子剂量仪器的标校,还可以针对具体能量段进行中子防护设计,精准有效指导外照射剂量防护工作的开展。 相似文献
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绝缘体上硅(SOI)硅微剂量测量系统可以通过测量中子和伽马混合辐射场的线能谱来获取不同类型辐射的剂量当量贡献。本文根据SOI硅微剂量探测器物理设计,采用GEANT4软件建模对Cf-252中子和伽马混合辐射场及Co-60伽马辐射线能谱测量进行蒙特卡罗模拟,并进一步分析了SOI探测器转换层对伽马线能谱测量的影响。结果表明,SOI硅微剂量探测器能够区分中子和伽马的剂量贡献,并且伽马线能谱峰值随着转换层厚度发生变化,有可能利用该特性实现不同贯穿深度下伽马辐射剂量贡献的测量。模拟分析结果可为SOI硅微剂量探测器设计及应用提供参考。 相似文献
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曲冰刘保生李秀川张敬之薛东帅 《辐射防护通讯》2022,(6):21-26
反应堆现场中子能谱对评估反应堆设施的设计以及对工作人员的辐射防护监测有重要意义。本工作利用两台反冲质子谱仪及一台便携式中子剂量仪,对某CPR1000型机组反应堆厂房内6个不同标高处的中子能谱和中子周围剂量当量率进行了测量,并对结果进行了分析。为同类型机组现场中子能量分布提供参考数据。 相似文献
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Bonner球谱仪是开展中子能谱测量的重要仪器,本文利用自行研制的Bonner球谱仪对已知源强的Pu-Be中子源进行能谱测量,以验证谱仪测量方法和中子能谱解谱方法的准确性。首先制作出由8个球组成的Bonner球谱仪,再根据谱仪的测量读数,采用最大熵法获得中子能谱信息,与国际原子能机构公布的数据基本符合,进一步计算得到所测Pu-Be中子源的中子周围剂量当量转换系数为0.37nSv.cm2,与目前已经公布的数值0.36nSv.cm2基本一致,表明求解出的能谱测量数据基本符合物理事实,测量所使用的Bonner谱仪和解谱方法的准确可靠性。 相似文献
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钍基熔盐堆10 MW固态实验堆设计采用活化法测量反应堆内部中子能谱分布,中子活化样品在堆外装载后通过传输装置将其快速输送到堆内测量位置进行辐照,辐照完后将其输出到能谱样品间进行解谱分析,进而获取堆内能谱分布情况。为实现中子能谱样品快速进出反应堆,设计了一种堆内双层套管中子活化样品气力输送系统,采用Fluent仿真方法研究样品在不同管道间隙下的运动规律。采用气力输送理论对原理样机的流量、两相流压损等工作参数进行设计并对原理样机的结果进行对比验证试验。试验结果表明:样品运动速度、气体流量和压损等测量参数与理论设计值符合较好,设计方法可行,双层套管的结构设计可以实现样品顺畅进出堆芯的功能。 相似文献
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阈探测器是研究中子能谱的一种有效工具,而中子能谱是解决某些辐射剂最学问题(其中包括确定紧急核事故中子剂量)所不可缺少的资料。用核乳胶和活化阈探测器测量事故中子剂量有一定的局限性。1967年,K.Becker 等人提出用“非照相方法”测量事故中子个人剂量的建议,并用天然铀和聚碳酸酯制作一种简单的裂变径迹个人中子剂量计~([1])。近年来,我们也研制了这种固体裂变径迹中子剂量计。在超临界紧急事故中,应用这种剂量计来测量中子剂量具有许多明显的优点:测量速度快,可测量的剂量范围大,环境适应性强和径迹计数能自动化等。其缺点是剂量计本身固有的γ放射性虽然已降低到很弱,但仍高出环境本底 相似文献
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Wu Yu Wang Shouguo 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(18):3137-3139
A facility which is called atmospheric pressure and normal temperature plasma jet was introduced in this paper. After the wool surface was treated by this kind of facility with Ar in different irradiating times, the time-effect of the fabric wettability has been weakened, and if the parameters of the irradiating time and the voltage of the facility are appropriate, the time-effect of wettability can be effectively inhibited. With the stable wettability, the fabric can be dressed without PVA (polyvinyl alcohol) which can cause lager pollution in the textile field, so the method without the time-effect of the textile wettability will be useful in the field of clean textile production. Undoubtedly, the stable wettability of textile surface was caused by the stable hydrophilic molecules on the textile surface. Thus, the reaction process and results on the textile surface treated by plasma needs to be studied to optimize the parameters of the irradiating time and the voltage of the plasma jet. So the initial experimental studies on the optimization of the parameters of the plasma jet were discussed in this paper, and the authors believe that the method without the time-effect also can be used in other fields of plasma application. 相似文献
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《等离子体科学和技术》2016,18(4):382-387
In this paper,a two-dimensional physical model is established according to the discharging process in the Hall thruster discharge channel using the particle-in-cell method.The influences of discharge voltage on the distributions of potential,ion radial flow,and discharge current are investigated in a fixed magnetic field configuration.It is found that,with the increase of discharge voltage,especially during 250-650 V,the ion radial flow and the collision frequency between ions and the wall are decreased,but the discharge current is increased.The electron temperature saturation is observed between 400-450 V and the maximal value decreases during this region.When the discharge voltage reaches 700 V,the potential distribution in the axis direction expands to the anode significantly,the ionization region becomes close to the anode,and the acceleration region grows longer.Besides,ion radial flow and the collision frequency between ions and the wall are also increased when the discharge voltage exceeds 650 V. 相似文献
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Bo LIU 《等离子体科学和技术》2022,24(11):115301
The electromagnetic pulse excited by the collision between a hypervelocity meteoroid and a spacecraft is studied both numerically and theoretically. It is found that there are two kinds of electromagnetic pulse. The high-frequency electromagnetic pulse may be excited by the sum of all the electric dipoles. Each electron can be considered as an electric dipole. The low-frequency electromagnetic pulse is produced by the Langmuir oscillation of electrons. The energy flux density and the duration time of the excited low-frequency electromagnetic pulse by the meteoroid are also studied in the present paper. It is shown that the energy flux density increases as either the impact speed or the mass of the meteoroid increases. It is also shown that the duration time decreases as both the impact speed and the mass of the meteoroid increase. By measuring the strength and the duration time of the electromagnetic pulse excited by the collision between the hypervelocity meteoroid and spacecraft, we can estimate the speed and the mass of the hypervelocity meteoroid, which will be helpful in space flight and space exploration. 相似文献
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为探讨右侧卧位对左室下壁心肌衰减校正和心梗诊断的价值,对31名正常者和22名冠心病病人同时进行了仰卧位和右侧卧位的^99mTc-MIBI静息心肌显像,病人均作了冠状动脉血管造影。观察正常者在不同体位时下壁形态并通过靶心图计算各区象素计数。判定不同体位各供血区病变诊断的敏感性和特异性。结果表明,右侧卧位时下壁形态显示较好而且计数明显增高,P<0.05,同时对右冠状动脉病变的敏感性和特异性分别为100%和81.8%,较仰卧位明显提高,结果提示,右侧卧位不仅可使下壁衰减得以校正而且可提高对心梗诊断的准确性。 相似文献
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M. Yamamoto F. Arbeiter T. Yokomine E. Wakai J. Theile A. Garcia D. Rapisarda N. Casal A. Mas P. Gouat W. Leysen 《Fusion Engineering and Design》2013,88(6-8):746-750
Under Broader Approach (BA) Agreement between EURATOM and Japan, IFMIF/EVEDA (International Fusion Materials Irradiation Facility/Engineering Validation and Engineering Design Activities) has been performed since the middle of 2007. IFMIF presents three main facilities (the Accelerator Facility, Li Target Facility and Test Facilities). A previous design of IFMIF was summarized in the comprehensive design report [1]. The present EVEDA phase aims at producing a detailed, complete and fully integrated engineering design of IFMIF. The delivery of the “Intermediate IFMIF Engineering Design Report” is foreseen mid-2013. The goal of IFMIF is to obtain the indispensable design database to allow the design and licensing of DEMO and ensuring commercial reactors thanks to the materials data set obtained from planned evaluation tests such irradiations in high flux test modules (HFTM-vertical rig, HFTM-horizontal rig), medium flux test modules (creep fatigue test module, tritium release test module, liquid breeder validation module) and low flux test modules of IFMIF. In addition, the Startup Monitoring Module will be used for IFMIF commissioning. This paper is summarizing the overall current progress status of the engineering and conceptual design of the test modules in IFMIF/EVEDA. 相似文献
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本文通过对反应堆周期计响应时间、过冲量及噪声问题的分析,探论周期测量和周期保护信号分别处理的必要性和可能性,目的在于改善周期信号的品质,提高周期计的使用效果。本文首次报道了差分型周期计的响应函数。 相似文献
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