含氚硅胶中氚回收率的测量

采用加热解吸结合催化氧化及吸附法对含氚硅胶中的氚回收率进行了精确量化.结果显示,含氚硅胶中的氚主要以化合态的形式存在,含氚硅胶中氚回收率随样品的加热解吸温度的升高而增加,在相同的解吸温度下,含氚硅胶中氚回收率随载气流速的增加而呈下降趋势,在解吸温度为500℃及载气流速为60 mL/min下仍有5%以下的氚滞留在硅胶中,...     

尿氚制样系统的研制

为改善尿氚制样过程中自动控制差、制样效率低、操作流程复杂、耗能高等问题,研制了一套用于尿中氚分析的快速、批量尿氚制样系统,并通过相关实验对系统性能进行了测试。结果表明,系统制样的最佳制样条件是加热温度为200℃,蒸馏冷凝时间为10 min;系统制样稳定度高,重现性好,较以往的尿氚蒸馏装置制样效率提高了5倍,能耗降低了1/3,操作流程实现自动化。     

退役核设施不锈钢中氚的分析

在自制的氚污染不锈钢的高温热解析制样系统中对氚污染不锈钢样品进行解析分析,并对影响不锈钢样品中氚回收率的解析温度、解析时间、催化氧化效率、冷凝收集效率等条件进行了优化研究。结果表明,当载气（空气）流速为60～80 L/h,解析温度和催化氧化温度为700 ℃,冷凝温度为-20 ℃,解析时间为2 h时,氚污染不锈钢样品高温制样系统的冷凝收集效率为99%,催化氧化效率为98.6%,不锈钢样品中氚的解析率＞95%。以上结果表明,该不锈钢高温热解析制样系统及其解析条件能够满足退役核设施不锈钢样品中氚的分析要求。     

监测环境空气中氚(HTO)的简便方法

本文介绍了一种测定环境空气中氚(HTO)浓度的方法。本方法以变色硅胶作为干燥剂,置于环境空气中自行吸收空气中的氚化水蒸汽,用加热蒸馏法将硅胶吸附的水蒸汽解析制备成水样品,在液体闪烁计数器上测定其氚的活性,根据采样时的温度和相对湿度估算空气中氚(HTO)的浓度。本方法的探测下限不仅与所用的液体闪烁计数器的灵敏度、本底有关,而且与环境温度和相对湿度密切相关。现场实验表明,本方法灵敏度高,简单易行,且不受样品数量限制,特别适用于较大范围内环境空气中氚浓度监测工作。     

松针中组织自由水氚的测量

本文用生物样品与有机溶剂共沸蒸馏分离法对秦山核电厂附近秦山上松针中组织自由水氚进行测量。选择甲苯为共沸蒸馏溶剂。松针与甲苯共沸蒸馏,组织自由水回收率达90%。结果表明,松针中组织自由水氚浓度为1.8 Bq/L,与同期大气中氚化水蒸气(HTO)的浓度在同一水平。     

氚监测中蜂蜜样品的处理方法

本文介绍了一种氚监测中蜂蜜样品的处理方法。样品处理装置由供蜜、供氧系统、石英催化燃烧室和冷却系统组成,蜂蜜经蒸馏、裂解和炭化过程,生成水蒸汽。该装置对氚水和有机氚的回收率分别为99.0±4.5%和96.0±2.0%。     

低温解析-液闪法检测植物中氚含量

为评价涉氚活动中氚对环境的影响,建立了低温解析—液闪法检测核设施周围植物样品中氚含量的分析方法。该方法将核设施周围植物样品中组织自由水氚(TFWT)在110~120℃解析出来,用液闪计数仪测量其氚含量。该分析方法比传统分析方法缩短约120 min,对植物样中TFWT的平均回收率优于76%,能够满足涉氚场所植物中TFWT的快速分析。     

高压氘氚气氛下铜对氚的吸附

为了解氚在铜表面的吸附和解吸行为，对铜样品在n（D）∶n（T）=1∶1，503 K时，15 MPa下恒温8 h后，再在27 MPa恒温6 h下进行了氚的吸附，并对吸附氚的铜样品在室温下和加热到1 173 K时的解吸氚量和吸附总氚量进行了测量。结果表明，铜的吸附总氚量为31.89 MBq/cm²,解吸氚量为29.18 MBq/cm²，测量的标准差为6.49％；室温和加热条件下铜所释放的氚中，化学成分主要是HTO和HT，大部分以HT形式存在；铜的自由氚量占吸附总氚量的3.64 ％；铜的热解吸谱至少存在3个解吸峰，其解吸温度分别为650，750和1 173 K以上。     

土蕊样品含氚量的测定

本文介绍一套真空加热解析装置,可将5g数量的土壤样品所含的90％的HTO在2h内解析收集到冷凝瓶中,制成液闪测定样品。该装置和方法在放射性示踪核素迁移实验研究中,已用于土蕊样品含氚量的测定。     

分子筛床对氚化水气体过滤效能的研究

为了准确掌握分子筛床在现场的实际防护效果,需要进行含氚(氚化水,HTO)空气穿透实验。将露点一定、氚浓度一定的普通氮气以稳定的流速通过分子筛床,并连续测量气体通过分子筛床前后氚浓度的变化和分子筛床穿透前后的质量变化,从而确定分子筛床在现场实际环境中的防氚效果。实验结果表明,无水分子筛床的氚化水吸附效果最好,4 h之内的过滤效率保持在95%以上,过滤效率高,使用时间长;1/3吸水的分子筛床的吸附效果较好,3 h之内过滤效率保持在90%以上。综合考虑使用舒适度和过滤效能,1/3吸水的分子筛床更适合用于现场的实际氚防护。     

氚化水蒸气硅胶取样方法研究

本文研究了用硅胶取样空气中氚化水蒸气的简便方法。提出两个估算空气中氚化水蒸气浓度的公式,一个不包括取样效率,适用于快速取样或直接暴露取样,另一个不包括相对湿度,适于对结果要求更加准确的场合。     

Effect of hydrocarbons on the efficiency of catalytic reactor of detritiation system in an event of fire

Detritiation system of a nuclear fusion plant is mandatory to be designed and qualified taking carefully into consideration all the possible extraordinary situations in addition to that in a normal condition. We focused on the change in the efficiency of tritium oxidation of a catalytic reactor in an event of fire where the air accompanied with hydrocarbons, water vapor, and tritium is fed into a catalytic reactor at the same time. Our test results on the effect of these gases on the efficiency of tritium oxidation of the catalytic reactor indicated; (1) tritiated hydrocarbon produces significantly by reaction between tritium and hydrocarbons in a catalytic reactor; (2) there is little possibility of degradation in the detritiation performance because the tritiated hydrocarbons produced in the catalyst reactor are combusted; (3) there is no possibility of uncontrollable rise in the temperature of the catalytic reactor by heat of reactions; and (4) saturated water vapor could temporarily poison the catalyst and degrades the detritiation performance. Our investigation indicated a saturated water vapor condition without hydrocarbons would be the dominant scenario to determine the amount of catalyst for the design of catalytic reactor of the detritiation system.     

Hidex 300SL液闪装置测量低水平氚水活度的参数优化

Hidex 300SL是基于三管符合计数/两管符合计数(TDCR)方法绝对测量低水平氚水活度的液闪装置。本工作基于该装置对标准非淬灭氚水样品进行测量研究,明确了系统的探测效率与TDCR的关系;讨论了该装置的测量模式、符合时间等参数对计数率、衰变率和TDCR的影响;并对仪器的运行参数进行选择优化,在"H-3"测量模式及35ns的符合时间窗下,系统对3 H的探测效率达73.2%,衰变率稳定性好于0.47%;最后对空气本底样品进行测量,评估了该装置对氚水样品的探测下限,为后续环境低水平样品的精确测量提供有益参考。     

基于铝箔封装碳酸锂探测片产氚率测量的液闪样品制备方法

氚增殖包层中产氚率的测量是聚变核能系统中需要研究的重要问题之一,本文开展了用于产氚率测量的Al箔封装碳酸锂探测片液闪样品制备化学处理方法的研究。结果表明,首先采用氢氧化钠溶液来溶解Al箔,然后再用盐酸溶解碳酸锂探测片的溶解方式,能制成透明度高且无分层的液闪样品。为了提高测氚计数效率和保证样品兼容性,对20 m L的标准液闪样品,闪烁液体积应至少取12 m L,同时还应将液闪样品保持在10-20°C范围进行储存和测量。     

Tritium dose criteria and radiological impact of a tritium plant

Radiation safetry criteria adopted in Russia (in the former USSR) distinguish five classes of tritium compounds. The lowest permissible tritium concentration in the air is set for insoluble tritium compounds (3.10⁵ times lower than that for HT). Russia's criteria for tritiated radioactive waste are outlined. It is explained why the tritium weighting factor of two is used as a basis for the tritium dose criteria development in this country. The ecological situation nearby a large tritium processing plant is considered. Amounts of tritiated waste produced at the plant, sources of tritium effluents, tritium content in the air, water, snow, soil and vegetation as well as HTO sorption parameters of various food products are reported. On the basis of HTO near-surface concentrations in the air and public doses measured 3 km away from the plant stack, the tritium dose factor was calculated.     

Tritium permeation experiments using reduced activation ferritic/martensitic steel tube and erbium oxide coating

Low concentration tritium permeation experiments have been performed on uncoated F82H and Er₂O₃-coated tubular samples in the framework of the Japan-US TITAN collaborative program. Tritium permeability of the uncoated sample with 1.2 ppm tritium showed one order of magnitude lower than that with 100% deuterium. The permeability of the sample with 40 ppm tritium was more than twice higher than that of 1.2 ppm, indicating a surface contribution at the lower tritium concentration. The Er₂O₃-coated sample showed two orders of magnitude lower permeability than the uncoated sample, and lower permeability than that of the coated plate sample with 100% deuterium. It was also indicated that the memory effect of ion chambers in the primary and secondary circuits was caused by absorption of tritiated water vapor that was generated by isotope exchange reactions between tritium and surface water on the coating.     

Optimization for the tritium isotope separation factor and permeation by selecting temperature and thickness of the diffusion Pd-Ag alloy cathode

Large quantities of tritiated water will be produced in the controlled fusion reactors for power generation. To eliminate the concentrated tritiated water and for recycling tritium, an industrial electrolyzer was developed. The aim of this paper is to give the design of this electrolyzer and the results for optimization in diffusion and in isotopic exchange by selecting thickness of a thimble-shaped Pd-25%Ag cathode working at high temperature and current. In this process, the tritium recovery system is based on the principle of the tritium diffusion Pd-Ag cathode which produces very pure hydrogen isotopes from enriched tritiated water.