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Construction of the standard system for absolute measurement of tritium

氚绝对测量标准体系的构建

基本信息

批准号：
15206103
负责人：
MATSUYAMA Masao
金额：
$ 29.12万
依托单位：
University of Toyama
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15206103/
关键词：
tritiated water non-destructive measurement heat of decay calorimeter standard system fusion reactor tritium plant トリチウム

项目摘要

To evaluate the absolute amount of tritium, a calorimetric system was designed and constructed, and its basic performance has been tested. The calorimetric system is applicable to measure solid, liquid and gaseous tritium. For this application the present calorimetric system is equipped with a high sensitivity calorimeter, a tritium container, total pressure gauges, a quadrupole mass spectrometer, and high vacuum systems. A twin type thermal conductivity calorimeter with a vacuum shielding was specially employed for the present purpose. A calibration curve of the calorimeter has been prepared at first using solid materials absorbed a given amount of tritium, and the following linear relation was obtained : E_<out>=(0.2694±0.0010) Q_<in>, where E_<out> describes the output (μV) from the heat sensors and Q_<in> the input power (μW) by Joule heating to the sample cell. In addition, the lower detection limit was estimated to be 0.15μW from stability of the calorimeter, which corresponds to the tritium amount of 0.16 GBq. As the first test, Zr-Ni alloy powder loaded with a given amount of tritium was measured by the calorimeter and the amount of tritium was evaluated to be 26.3 GBq, which was a little lower than the tritium activity determined previously by using a small ionization chamber. The second test was applied to measurement of tritiated water. The observed calorific value was about ten times greater than that of the expected value. It was seen that this is due to the oxidation reaction of a liquid cell with oxygen dissolved into tritiated water. Improvement of a liquid cell will lead to successful measurements of tritium.

为了评估氚的绝对量，设计并构建了量热系统，并测试了其基本性能。该量热系统适用于测量固体、液体和气态氚。对于该应用，本量热系统配备有高灵敏度量热计、氚容器、总压力计、四极质谱仪和高真空系统。为此，专门采用了带有真空屏蔽的双型热导量热仪。首先使用吸收给定量氚的固体材料绘制热量计的校准曲线，并获得以下线性关系：E_<out>=(0.2694±0.0010) Q_<in>，其中E_<out>描述热传感器的输出（μV），Q_<in>描述焦耳加热到样品池的输入功率（μW）。此外，根据量热计的稳定性估计检测下限为0.15μW，对应于0.16GBq的氚量。作为第一个测试，通过量热计测量负载一定量氚的Zr-Ni合金粉末，评估氚量为26.3GBq，略低于先前使用小型电离室测定的氚活度。第二个测试应用于氚化水的测量。观察到的热值比预期值高出约十倍。可以看出，这是由于液体电池与溶解在氚化水中的氧发生氧化反应所致。液体池的改进将导致氚的成功测量。