Pre-conceptual design of a gas-cooled microreactor with two-phase composite moderators

Interest in microreactors because of the need for energy in remote locations is leading to the development of new nuclear energy technologies. These technologies are aimed at reducing overall core size without compromising on safety. The HTGR size limitation is primarily based on the graphite moderator. By replacing graphite with a beryllium-based moderator, a larger power output or longer cycle length could be achieved. Early optimization studies show significant gain in performance for all cases. Optimization studies are currently being expanded to fully harness the moderating capabilities of the beryllium moderators. Parametric studies show acceptable design criteria for pressure, moderator temperature, and cycle length limitations for beryllium-based moderators.