Effect of Hydrogen Concentration on Neutron Moderation of Hydrides at 900 K

Published

September 5, 2025

Author(s)

Moiz Butt, Abdullah Weiss, Erik Pavlina, Thomas Nizolek, Michael Hahn, Caitlin Kohnert, Sean McDeavit, Erik Luther

Abstract

The neutron attenuation and permeation characteristics of several metal hydrides were studied to determine the efficacy of metal hydrides as neutron moderators and shields. These metal hydrides comprised yttrium, zirconium, and yttrium-chromium-based hydrides and deuterides. Neutron attenuation coefficients (μ_n) and neutron permeation coefficients (ξ_n ) of these hydrides were determined using Monte Carlo N-Particle (MCNP) transport simulations. The effect of impurities on the moderating efficacy of specific hydrides was evaluated by comparing ideal, or pure, hydride compositions with hydrides of metals containing impurity levels typical of commercially available metal alloys. The analysis showed that metal alloy hydrides, particularly those of a yttrium-5wt% chromium and other impurity containing yttrium materials do not significantly decrease the moderating capability of the moderator when compared to pure yttrium. The analysis also compared the difference in moderating capabilities between the different hydrides of yttrium and zirconium, where zirconium performs better for neutron attenuation, but yttrium performs better with respect to neutron permeation over the range of energies investigated.

Citation

Annals of Nuclear Energy

Pub Type

Journals

Keywords

Yttrium, Zirconium, Hydride, Hydrogen, Moderation, Shielding, Attenuation, Permeation, Neutron

Citation

Butt, M. , Weiss, A. , Pavlina, E. , Nizolek, T. , Hahn, M. , Kohnert, C. , McDeavit, S. and Luther, E. (2025), Effect of Hydrogen Concentration on Neutron Moderation of Hydrides at 900 K, Annals of Nuclear Energy (Accessed October 13, 2025)