Tritium behavior in the primary coolant of bebble and prism type gas cooled reactor

In 2004, the Korea Atomic Energy Research Institute (KAERI) launched a nuclear hydrogen program in which it aimed to develop and demonstrate by 2019 a mass producing hydrogen. Preconceptual designs for both pebble and block-type HTGR cores are being performed. Because the main purpose of these reactors is to produce heat-induced hydrogen, none of the radioactive nuclide must contain in any generated hydrogen. Furthermore, because tritium is the only radionuclide that can permeate from the primary circuit through the heat exchanger walls into the secondary circuits where it causes unwanted contamination, this nuclide is of particular interest in relation to high-temperature gas-cooled reactors. This study is based on the conceptual design parameters of a gas turbine-modular helium rector (GT-MHR) which is 600 MWth and a PBMR which is 300MWth because these types of reactors are reference reactors of the nuclear hydrogen program. Tritium is produced in the HTGR by ternary fission and by activation reactions among trace impurities of the reflector grahphite and control materials that contain Lithium and boron. In addition, a HTGR-specific tritium source is given by the helium coolant itself in the form of the neutron-absorbing nuclide 3He, which has an abundance of extremely low isotopes. Compared with these sources, the contributions of other tritium-producing reactions with nuclides such as 9Be or 12C are negligible