³He Release From Ti, Zr, Er and Nd Tritides

3He release from 4 kinds of metal tritide such as Ti, Zr, Er and Nd were measured by means of QMS method. Comparison of ³He release behavior among them shows that their 3He release rates are very low which are less than 1% of their 3He generation rate, and 3He release factors are 10^－6-10^－5 for Ti and Zr tritides and 10^－3 for Er and Nd tritides. Their 3He release factors will increase rapidly to 10^－1 level while enough ³He accumulates in metal tritides with storage time increase.