Abstract: The leak of tritium will cause radiation hazard for public safety and environment, therefore the leak of tritium contained pipes should be analyzed. The tritium contained pipes of the ITER gas injection system are analyzed in this paper. An estimation on the air equivalent leak rate at the tritium alarm threshold (3×10⁵ B_q·m^-3 for environment, 1×108 Bq·m‒3 for pipes) is given for the leak of the tritium supply pipe, the neutralizer pipe and the ion source pipe. The results show that the leak of the tritium supply pipe has highest risk. Although the tritium supply pipe operates at a pressure lower than that in the surrounding enclosure, leak rate higher than 3.2×10^-8 Pa·m³ ·s^-1 will trigger the tritium alarm due to high tritium concentration. To the contrary, the ion source pipe operates at a much higher pressure than that in the surrounding enclosure but has low tritium concentration. It will trigger the tritium alarm at leak rate higher than 6.1×10^-6 Pa·m³ ·s^-1 . The leak hazard of tritium contained pipes of gas injection system is not negligible, and real time monitoring and protecting is necessary. 

Key words: Tritium supply pipe, Ion source pipe, Neutralizer pipe, Leak, Diffusion 

摘要： 氚的泄漏会对公众安全和环境造成危害，有必要对含氚管道的泄漏进行分析。对 ITER 气体注入系 统的含氚管道进行分析，对触发系统氚报警阈值(3×10⁵ B_q·m^-3 /环境安全值，1×10⁸ B_q·m^-3 /系统安全值)时，氚送气 管、离子源管以及中性化管泄漏的等效空气漏率进行了计算。结果表明，氚送气管泄漏的风险最高。虽然氚送气 管的气体压力低于包容管的夹层压力，但由于管道的氚浓度高，漏率大于 3.2×10^-8 Pa·m³ ·s^-1时会触发报警。而在 离子源管中虽然氚浓度低，但管道的气体压力远高于包容管的夹层压力，漏率大于 6.1×10^-6 Pa·m³ ·s^-1 时会触发氚 报警。气体注入系统含氚管道泄漏的氚危害不可忽视，必须进行实时监测和防护。 

关键词: 氚送气管, 离子源管, 中性化管, 泄漏, 扩散