Feasibility of Using BeO Rods As Secondary Neutron Sources in the Long-Life Fuel Cycle High-Temperature Gas-Cooled Reactor

External sources of neutron provide stable and sufficient neutron for initial startup of a nuclear reactor. They also provide signals for neutron detectors to monitor the safety of reactor during shutdown. In the high temperature engineering test reactor (HTTR), Cf-252 is used as the external neutron source. However, the Cf-252 sources must be renewed every approximately 7 years because of its relatively short half-life of 2.6 years. The renewal of Cf-252 sources requires a high cost and a very complicated procedure. This study investigated the feasibility of using BeO rods as the secondary neutron sources to avoid renewing the Cf-252 neutron sources periodically. The BeO rods could exist in the reactor for a long time so that if the reactor operates long enough, the neutron flux at the wide-range monitoring detectors remains more than 10n.s(-1).cm(-2) even if the reactor is shutdown for as long as 5 years. The results of this study indicated that using BeO rods as the secondary neutron sources would be an attractive option for the future HTGR design with a long-life fuel cycle.