流气延时法测量氡(气)/(土)浓度的研究

文章涉及同时测定氡气土浓度的方法———流气延时法。该方法采用两套闪烁室测量装置和1台由50mmPVC U排水管和50mmPVC U接头制成的总体积为24L的延时装置。当氡气土混合气体以恒定流率3L·min-1流经测量系统时,延时装置后的闪烁室测量装置测定气土室中氡的参考浓度,延时装置前的闪烁测量装置经扣除气土的贡献后可测定气土室中气土的参考浓度。流气闪烁法测氡气土浓度的刻度因子的不确定度小于5.0%。     

基于单小闪烁室延时法绝对测量222Rn／220Rn方案验证

文章提出了单小闪烁室采用延时法对222 Rn/220 Rn进行绝对测量的方案,并给出了使用222 Rn对这种方案进行验证的条件,设计了验证实验.实验结果表明,延时后小闪烁室的浓度与球形闪烁室作为参考值的偏差在-2.9%～+3.4%之间.从小闪烁室的浓度随时间的波动来看,延时后最佳测量氡的时间段是10～45分钟.实验证明采用单小闪烁室延时法对222 Rn/220 Rn浓度进行绝对测量是可行的.     

气球法环境中氡(气土)测定

由于大气环境中氡(气土)浓度比矿井中的浓度低3～4个数量级,因此要求测量方法灵敏度高、本底低以及能在测氡时排除(气土)的干扰,在测(气土)时排除氡的干扰。目前国内测氡普遍采用的活性炭吸附-加热解析-电离室静电计测定方法,不仅速度慢而且操作过程较长,人为影响因素难于控制。其它测(气土)方法如静电计法、闪烁室法、活性炭滤纸法等灵敏度也较低。美国能源研究和发展管理署保健和安全实验室(HASL)的大体积双层滤纸法(ERM-2型及ERM-3型)灵敏度虽较高(0.01pCi/1),但测定时间仍过长,且装置也较庞大。     

氡、(气土)子体浓度测量数据的微型计算机处理

吸入含有氡、(气土)子体的空气会使人体肺组织受到电离辐射的照射,多年来人们对测定氡、(气土)子体浓度的方法进行了大量的研究,归纳起来可分为两类:(1)总α放射性测量法。滤膜采样后,用α探测装置测定RaA和RaC′放出的总α计数,从而计算出RaA、RaB和RaC浓度。由于测量条件和需要测定的核素不同,而选择各种各样的测量时间。(2)α能谱学方法,可更准确地测定氡子体的浓度。滤膜采样后,在两段时间内用α谱仪测定滤膜上RaA衰变放出的6MeV和RaC′衰变产生的7.68MeV的α计数,从而算出RaA、RaB和RaC浓度。     

在南马奇铜铀矿点上进行的铀矿勘探方法的比较

概述在过去的二年中,铀的许多地球化学勘探方法已在安大略省南马奇的已知铜铀矿点上进行了试验。进行此项工作的目的部分是为了进行方法比较,部分是为了改进并试验新方法。此项研究工作所包括的方法如下: 射气测量方法把气体抽到闪烁室或射气仪中来测量土壤气中的氡。收集器方法收集器可以是金属丝、塑料片或金属,把它们悬挂起来测量空气或土壤气中的氡浓度。氡的衰变产物(~(218)Po、~(214)Pb、~(214)Bi和~(214)Po)沉淀或聚集在这些收集器上。收集器上沉淀物的α放射性与它所在的空气中的氡浓度成正比。把收集器悬挂在闪烁室中进行测     

第二次全国矿山辐射环境学术讨论会论文题录

铀矿山测尘技术的发展方向 吴静固体径迹探测器的α能量分辨特性 王瑞凯等广州市区空气中氡、(气土)及其子体浓度调查 吴增汉等局部静态法测多孔介质氡析出率 张哲改进的块状矿样射气系数测定的γ法 丘寿康改进的循环法转移氡装置 吴桂惠等     

闪烁室法现场水中氡浓度测量及其仪器功能开发

ZnS(Ag)闪烁室法水中氡浓度测量仪具有准确度高,探测下限低,操作简便,受湿度影响小的优点。从方法原理、测量装置及软硬件设计进行阐述,探讨了影响仪器测量准确性的因素。用液体镭源测试的结果验证了仪器的线性和准确性,其线性相关系数为0.9811,相对误差为-17.16%~10.21%;并与RAD7测氡仪水中氡浓度测量的数据作对比,相对误差在-14.28%~18.57%。     

用加电场法测定(气土)浓度

根据加电场测氡理,利用(气土)产生的初始游离态ThA具有正电荷、能在电场作用下收集的特性,使用FDC-80加电场测氡仪,测定(气土)浓度。对方法的理论计算公式和使用条件进行了一些探讨;并与静电计和气球法测(气土)方法作了对比实验,表明该方法在快速和精确度上较上述方法有着优点。若对装置进一步改进,灵敏度可高于上述方法。     

保加利亚放射性测量简况

苏联文摘1986年5(?)297和5(?)296报道了保加利亚一些放射性测量情况: 用闪烁爱曼仪(?)-6(?)从1978年9月1日起系统地观察了索非亚矿泉水中的氡浓度,此矿泉水位于两组断层构造(N-W和N-E)的交叉部位。文章中介绍了测量方法。在地震相对稳定期间氧浓度为11.8Bq/1(3.2em)。但在1980年3月9日20时30分记录到氡的微弱增高(13Bq/1),这个增高是由于距索非亚50km处于1980年3月9日18时18分发生了地震所致。在地震后的一个月发现了最高氡浓度为15.5 Bq/1(4.2 em)。山此可得出看法:氡法和其它方法配合可用于预报地震。文章还介绍了应用真空法和循环装置测量水中氡浓度的方法、技术和解决地震预报问题。     

广州地区室内氡、(气土)浓度随季节及昼夜变化规律的探讨

本文报道1984年7月至1985年6月间在本院实验室内测定的氡、(气土)浓度随季节和昼夜变化的情况。结果表明氡浓度的昼夜变化为早晨6—7时较高,下午1—3时较低,最高与最低值之比达3—4倍,接近日平均水平的时间为上午8—11时;氡、(气土)浓度随季节的变化规律相似,都是冬季(1—3月)较高,夏季(6—9月)较低,氡、(气土)月平均浓度的最高和最低值之比,分别为7.0和5.0倍,春(4—5月)、秋季(10—12月)的氡,(气土)浓度都分别与其年平均水平接近。     

Sorption methods of separating barium and radium,aluminum and gallum,and zirconium and hafnium

Chromatographic methods of separating elements with very similar properties have now been developed. However, a number of these methods are difficult to use industrially as their throughput is low. The efficiency of chromatographic separation methods could be increased considerably by using appropriate complex formers, which decrease the effective concentration of the ions being separated, and,in the first approximation, this is equivalent to a decrease in the amount of elements being separated. The difference in the formation constants of the complex compounds increases the separation coefficient. By investigating chromatographic separation with the use of various complex formers, we found the optimal conditions for separating barium and radium, zirconium and hafnium, and aluminum and gallium. The throughput of these methods, with respect to the macroelement was 15–60 kg/hr per m² of column cross section.     

医源性电离辐射损伤及其生物医学防护

随着核与辐射技术在医学检查、诊断和治疗领域运用的增加,世界范围受照人群不断增多,医源性辐射已成为人类最主要的人工辐射来源之一。医疗机构和个人在选择利用放射手段获取诊断和治疗利益的同时,需要注意和防护伴随的辐射损伤效应。本文介绍了医源性辐射及其危害、机体组织的辐射损伤特性和类型、辐射生物效应分子及效应调节研究的进展,简要概述目前临床已经使用或最具应用潜力的辐射防护策略。     

Distribution and Fixation of Cesium and Strontium in Zeolite A and Chabazite

The selective removal and fixation of Cs and Sr have been studied in zeolite A and chabazite. Cesium ion was preferentially distributed into chabazite with a high distribution coefficient (K _Cs>10³ cm³·g^?1) in the presence of NaCl (10^?1 mol·dm^?3). The K _Sr values for zeolite A attained about 10³ cm³·g^?1 in the pH range of 8～10, and they gradually decreased with an decrease in pH.

The initial rate of Cs adsorption was fairly fast in chabazite, and the adsorption ratio reached almost 100% within a few hours. The adsorption ratio of Sr in binderless A zeolite reached almost 100% after 15 h. The adsorption of Cs and Sr on these zeolites was followed by Langmuir-type isotherm. Cesium forms of these zeolites recrystallized to pollucite (CsAlSi₂O₆) above 900°C for zeolite A and above 1,200°C for chabazite. As for Sr forms, these zeolites changed to SrAl₂Si₂O₆ above 900°C.

These recrystallized phases were suitable hosts for the immobilization of Cs and Sr in the nuclear waste solutions.     

清洁解控和退役若干动向与新发展

对国际辐射防护协会第 1 0届大会 ( IRPA-1 0 )涉及的清洁解控和退役问题作了论述 ,包括排除、豁免、清洁解控和废物最少化 ;退役工程技术的发展 ,包括去污技术、切割解体技术、探测技术 ;介绍了一个研究堆退役例子和加速器退役 ;最后 ,还论及了退役中受关注的一些问题 ,如 :石墨废物、混凝土废物、重水堆退役的氚防护、退役时间和退役废物量等。     

Development and diversity and defense-in-depth application of ABWR feedwater pump and controller model

This work developed an advanced boiling water reactor (ABWR) feedwater pump and controller model, which was incorporated into Personal Computer Transient Analyzer (PCTran)-ABWR, a nuclear power plant simulation code. The feedwater pump model includes three turbine-driven feedwater pumps and one motor-driven feedwater pump. The feedwater controller includes a one-element/three-element water level controller and a specific feedwater speed controller for each feedwater pump. The performance tests, including step change of dome pressure, feedwater pumps transfer, inadvertent closure of all turbine control valves, and one feedwater pump trip at 100% power, demonstrate the feasibility of dynamic response of stand-alone model and incorporated model. Furthermore, a diversity and defense-in-depth analysis is performed to demonstrate the feasibility for motor-driven feedwater pump as an emergency core cooling system (ECCS) automatic diverse back-up. In Lungmen nuclear power plant (NPP), a diverse manual initiation means for the high pressure core flooder (HPCF) loop C is designed as the back-up of digitalized engineered safety features actuation system (ESFAS). If the motor-driven feedwater pump (MDFWP) can be an automatic digital diverse back-up for ESFAS, Lungmen NPP would be more robust to defend against software common-cause failure (CCF).     

全国核与辐射安全监管信息系统的研究和建议

文章简要介绍了全国核与辐射安全监管信息系统的前期规划建设情况,包括基本建设内容、系统总体架构、以及工作中发现的影响和制约工作开展的主要问题,并提出了建议。     

Plastic and dissipated work and stored energy

This paper depicts one theoretical and experimental method to take into account the energy phenomena, associated with the elasto—plastic deformation process, during the elaboration of behaviour laws. The energy balance definition is examined in order to relate the stored energy of cold work to the hardening state variables. Two experimental approaches are used to study the evolution of the energy balance. The first one uses microcalorimetric technique and the second infrared technique. Several industrial metallic materials are studied by both approaches. Energy data are used to control the validity domain of the classical behaviour laws and to elaborate new more appropriate ones. Therefore, the hardening parameters cannot be identified with the thermodynamical forces. The use of energy considerations allows the definition of new thermodynamical forces and state variables, in the case of isotropic or kinematical hardening.     

Construction and operational experience with small and medium power reactors and expected improvements

Past experience with small and medium power reactors (SMPRs) in the areas of construction and operation is examined in this paper. Current development of SMPRs focuses on passive safety features; larger design and safety margins; reduction of construction periods through simplification, modularization and increased shop fabrication.