Tritium measurement I—tritium in gas, liquid, and solid

Since tritium (T) handled in fusion environment distributes so widely in its concentration and chemical form, no single T-measuring method can cover the wide concentration ranging from environment level (a few Bq) to carrier free level (GBq or above) and distinguish various tritiated compounds (gas, water, and organics). In principle, any methods used for hydrogen measurements can be used for T measurements. However, safety requirements owing to the radioactivity of T give limitation in the measurements. Furthermore, electric noises caused by β-electrons emitted at T decay often disturb the measurements. On the other hand, they are allowed to use the radioactivity measurement. Nevertheless, their energy is so low to make their detection difficult. In this chapter, the principle of T detection and measurements is introduced, and its applications are described targeting quantitative analyses of wide ranges of T in gas, liquid, and solid separately. In a fusion reactor, T in plasma is a new target to be quantified, which is described in Chap. 8, separately.