[en] In this study, the TRITGO code was introduced, which can predict the amount of tritium production, its transport, removal, distribution and the level of contamination for the produced hydrogen by the tritium in the VHTR (Very High Temperature Gas Cooled Reactor). The contamination level of the produced hydrogen by the tritium was predicted by an improved code for the VHTR with a 600 MW thermal power. The contamination level for the produced hydrogen by tritium was predicted as 0.56 Bq/H₂-g. This level is two orders lower than the regulation value of 56 Bq/H₂-g from Japan. From the analysis of the calculation results, it is important that the fuel coating (SiC layer) should be kept intact to prevent the tritium from releasing. Also it is necessary that the level of an impurity such as ³He and Li in the helium coolant and the reflector consisting of the graphite should be kept as low as possible. It was found that the capacity of the purification system for filtering the impurities directly from the coolant will be an important design parameter