Towards Measuring Hydrogen Dynamics in Yttrium Hydride Moderators

A compact, nuclear microreactor that utilizes low-enriched uranium fuel is a promising solution to meet US demands in remote and decentralized energy grids. Yttrium hydride (YH) is the candidate moderator material for the microreactor design, chosen based on its superior retention of hydrogen at high temperatures. Hydrogen diffusion properties in YH are highly sought after for computer model validation and reactor prototyping. To meet design objectives, the so-called compact dual-zone furnace was developed at the Los Alamos Neutron Science Center (LANSCE) with the goal of characterizing hydrogen diffusion in YH samples as a function of applied temperature gradients. Herein, we share our recent progress in technique and hardware developments and include initial results from recent concentration- and temperature-gradient measurements at LANSCE.[i]<br/>[i] LA-UR-22-22241