Conceptual Neutronic Design of a Research Pin-in-block type HTGR

The core neutronic design was performed for a research High Temperature Gas-cooled Reactor (HTGR) as a part of the research cooperation with Polish National Centre for Nuclear Research (NCBJ).This research HTGR is designed to supply high temperature steam for industrial use and has 30 MW thermal power.The design policy of the research HTGR is to construct it without any additional demonstration tests, i.e., using only proven technology in Japanese HTGR development, with the aim of deploying it in the 2030s.In the core neutronic design of the research HTGR, we have challenged to reduce the reactor core height, the number of fuel enrichments and the number of control rods compared with the High Temperature Engineering Test Reactor (HTTR) in Japan for the purpose of cost reduction.We have confirmed that the design feasibility parameters related to reactor shutdown margin, temperature coefficient, xenon spatial oscillation, maximum fuel temperature and kernel migration distance satisfy the prescribed limits.As a result, the core neutronic design has been completed successfully by shortening the reactor core height by one fuel block, reducing the number of fuel enrichments from twelve to three, and reducing the number of control rod from sixteen pairs to seven pairs.