同位素稀释-多接收电感耦合等离子体质谱法测量国际比对红酒样品中铅的含量

采用同位素稀释-多接收电感耦合等离子体质谱法(ID-MC-ICPMS)测量了国际比对红酒样品中铅的含量。因为红酒中铅含量仅有约3 ng/g,而流程空白却有0.3 ng,使本次测量几乎达到了方法检测限。比对结果表明,采用同位素稀释质谱法容易取得较一致的结果。在不确定度分析中将与方法相关的各项影响因素都做了定量分析,实际上,流程空白给实验结果精密度造成了很大的影响,从而增大了不确定度。因此,本方法中流程空白的控制在超低浓度样品分析中起到至关重要的作用。     

环境放射性样品的锗γ谱测量比对

本文报道中国计量科学研究院最近组织的一次环境放射性样品锗γ谱测量比对。21个比对实验室用锗γ谱仅测量了两个封装在凹形杯内的河泥样品中7种放射性核素的活度。比对取得比较满意的结果。掌握正确的测量分析方法和有可靠的刻度标准源是测量取得好的结果的重要原因。对比对测量中存在的问题进行了讨论。     

全国环境样品中放射性核素γ谱分析比对

介绍了国家环境保护总局组织的一次全国环境样品放射性核素γ谱测量比对。１４个实验室参加了比对,测量了土壤基质样品中的＾２３８Ｕ、＾２２６Ｒａ、＾２３２Ｔｈ和＾１３７Ｃｓ活度及生物样品中的＾１３７Ｃｓ和＾１３４Ｃｓ活度。比对取得比较满意的结果,同时也对比对测量中存在的问题进行了讨论。     

环境样品γ放射性测量国际比对

为了提高测量水平，促进环境样品放射性测量的质量保证工作，从１９８５年起本实验室开始参加环境样品放射性测量国际比对，本文报道了所参加的国际比对项目、γ放射性核素分析方法及部分比对结果。１　ＷＨＯ－ＩＲＣ和ＩＡＥＡ－ＡＱＣＳ比对项目从１９８５年到１９９３...     

^131I放射性活度的相对测量

本文报道选用与样品源相同的核素作标准源,运用稳定性较好的探测仪器,控制样品源与标准源测量时的相同几何条件,进行比对源~(131)I活度的相对测量,~(131)I测量值为672.6±4.7Bqmg~(-1),与4πβ-γ符合活度基准测量值670.8±2.7Bqmg~(-1)和各比对单位上报结果平均活度671.1±1.7Bqmg~(-1)相对误差均低于3‰,比对结果颇为理想,说明相对测量方法乃是目前基层放射性监测单位测量放射性活度行之有效的方法。     

铀同位素标准物质在核燃料系统实验室间比对中的应用

在核燃料系统分析检测实验室间比对活动中,首次开展铀同位素检测项目的设计、策划和实施,选取国家一级标准物质“八氧化三铀中铀同位素标准物质”作为分割样品对,分别采用Z比分数、标准物质测量结果的误差允许限(E)作为能力统计量,对实验室间铀同位素丰度的比对结果进行统计和分析,对测量结果有问题或不满意的情况进行分析和建议.通过首...     

广东核电站事故场外应急辐射测量比对

本文主要介绍了1998－1999年粤港地区“广东核电站事故场外应急辐射测量比较”的方法和结果。辐射测量比对项目包括环境贯穿辐射剂量率，辐射累积剂量和水与食品样品中γ放射性核素含量。文中还分析和讨论了测量比对中存在的问题。     

CTBT放射性核素实验室127Xe国际比对样品的实验测量研究

相较于全面禁止核试验条约关注的~(131)Xe~m、~(133)Xe~m、~(133)Xe和~(135)Xe 4种放射性氙同位素,~(127)Xe具有半衰期较长、样品纯度高、大气环境中本底低等特点,全面禁止核试验条约组织筹委会临时技术秘书处(Provisional Technical Secretariat,PTS)计划利用~(127)Xe进行国际监测系统(International Monitoring System,IMS)放射性核素台站的质量控制。为检验IMS国际放射性核素实验室对~(127)Xe的测量能力和水平,PTS组织开展了~(127)Xe样品的国际比对。描述了北京放射性核素实验室参加比对的样品测量流程和分析方法,将~(127)Xe样品定量转入测量源盒后,利用高纯锗(HPGe)γ谱仪系统测量了该比对样品的活度,测量结果为(53±10)Bq,与参考值偏差为4.3%。从比对结果看,北京放射性核素实验室测量结果准确可靠。     

供测量比对用土壤放射性样品的制备和应用

介绍了可供测量比对用的环境放射性模拟土壤样品及氚分析土壤样品的制备以及实验室比对结果。模拟土壤基质的化学成分为:SiO2、Al2O3、Fe2O3、MgO、CaO、NaCl、KCl、TiO2,掺合后基质经过研磨、干燥、过筛,加入放射性核素后充分混匀,按照GB 15000.5—1994的要求对模拟样品进行均匀性检验,未发现样品之间有显著性差异。3H分析样品为含水率15%的掺标自然土壤。8家实验室参加了该样品的相关比对活动,结果显示所研制的模拟土壤能够满足实验室间样品测量比对的要求。     

氢-氘体系的氘丰度质谱分析技术

介绍了用低分辨MAT253质谱计准确测量氢-氘体系中氘丰度的分析技术.通过建立实验室次级标准样品配气系统,并考虑氢同位素的灵敏度差异,测得了几何校正因子(k).对不同氘丰度的气体样品比对分析,2个独立检测的结果吻合较好.     

Need for and requirements for a neutron irradiation facility for fusion materials testing

The construction and operation of an intense 14-MeV neutron source is essential for the development and eventual qualification of structural materials for a fusion reactor demonstration plant (DEMO). Because of the time required for materials development and the scale-up of materials to commercial production, a decision to build a neutron source should precede engineering design activities for a DEMO by at least 20 years. The characteristic features of 14-MeV neutron damage are summarized including effects related to cascade structure, transmutation production, and dose rate. The importance of a 14-MeV neutron source for addressing fundamental radiation damage issues, alloy development activities, and the development of an engineering database is discussed. For these considerations, the basic requirements and machine parameters are derived.     

Criteria for Optimizing Technical Solutions for NPP

Atomic Energy - Criteria for optimizing technical solutions in designing and modernizing NPP are considered. Based on their analysis, it is shown that it is economically efficient to increase the...     

Experimental Results for an Acoustic Driver for MTF

General Fusion is planning to form an FRC or spheromak of 10¹⁷ cm⁻³, 100 eV, 40 cm diameter by merging two spheromaks with reverse or co-helicity. This target will be further compressed in a 3 m diameter tank filled with liquid PbLi with the plasma in the center. The tank is surrounded with pneumatically powered impact pistons that will send a convergent shock wave in the liquid to compress the plasma to 10²⁰ cm⁻³, 10 keV, 4 cm diameter for 7 μs. General Fusion has built a 500 kJ, 80 μs, 6 GW pneumatic impact piston capable of developing 2 GPa (300 kpsi). In this paper we will present the performances achieved to date.     

地震工况下设备土建载荷的计算方法

在设备抗震分析中,设备对基础的作用力是土建设计时所需的重要参数。本文根据不同的工程实例,给出2种设备在地震工况下土建载荷的计算方法,即简便方法和谱分析计算中的刚性区域法,并给出了算例。     

AC—600非能动安全特性分析

AC-600概念设计的研究重点包括堆芯、非能动安全系统及简化系统。本文讨论 AC-600自然循环能力、LOCA 或全厂断电期间,非能动安全系统的性能,也初步讨论了 AC-600对过剩反应性及热工水力瞬态的非能动限制。     

New code for digital imaging system for track measurements

A code for the numerical analysis of images from a CCD camera, including correction of acquisition system defects, has been written and applied to the visualization of α-particle tracks in the solid state nuclear track detectors CR39 and LR115. A standard mask having different diameter holes permitted the calibration of the imaging system. Comparison of manual scanning results with those given by the automatic system are presented for detectors exposed to α-particles of ²⁴¹Am source. As application, the system was used to measure specific activities of ²³⁸U in the Moroccan phosphates and their phosphogypsums samples by contact autoradiography.     

Principles for Finding Matrices for Immobilizing High-Level Wastes

The principles for selecting matrices for immobilizing high-level wastes are examined. It is concluded that actinides should be separated and embeeded in the matrix separately from fission products. The minimum significant specific activity, regulated by NRB-99, cannot be used to estimate the storage time. It is suggested that such values be established as a function of the leach rate of radionuclides and matrix materials from matrices. For this, a standard leaching method using pulverized materials must be specified. Two criteria are proposed for comparing matrix materials.     

Software for gamma cameras for mapping radioactive contamination

The software for portable systems for obtaining γ image with coding apertures (masks) is described. The software developed controls all systems that form an image and obtain shadow patterns, reconstructs the initial γ-image, and processes previously obtained images. The software is used with portable systems in which URA and MURA type masks with different rank are used as the coding aperture. Programs for modeling the process of obtaining shadow patterns using real apparatus which has different positionsensitive detectors are described. Possible configurations of new apparatus which could be of practical interest are examined.