Advancing microreactor materials technology: Next stop, the Moon!

Miniaturizing nuclear reactors offers a robust solution for generating reliable and efficient electricity, crucial for supporting human missions beyond Earth.

Such miniturization is not at all an easy task.

I have been pursuing research in this area since 2015, when we designed a ~ 3×3 metre-sized small nuclear reactor core for biological shielding optimization studies. In a compact reactor, it is essential to decrease both volume and weight while simultaneously increasing dose attenuation at positions outside the core.

The challenge lies, of course, in the seach for new materials. Developing microreactors is an even tougher task.

To reduce the kinetic energy of fast-born neutrons, a necessary step to achieve sustained nuclear fusion chain reaction, we need new moderator materials as traditional moderators like water and graphite are impractical in microreactors due to size constraints.

One solution is harnessing the power of hydrogen as a thermalizing agent for fast-neutrons. Hydrogen can be stored in the sub-lattice of most transition metals and form solid metal hydrides. The key scientific challenge in hydride moderators for microreactors is determining the stability of the hydrogen sub-lattice under the combined conditions of high temperatures and energetic particle irradiation. Hydrogen cannot depart solid-solution so the moderator power is lost.

In our new preprint, I have led coallition of scientists working in the USA in multiple and different areas of physics, metallurgy and materials science to target – once and for all – the stability of the most promising transition metal hydride candidate for moderators in microreactors: the yttrium dihydride (YH₂).

With this work, we aim to make a humble contribution to the future space exploration endeavors of the USA. The research conducted at LANL required significant effort and it took two years for completion, and I am particularly pleased with this latest preprint, marking the culmination of my tenure as a Director’s Fellow at the Los Alamos National Laboratory from 2021 to 2023.

We are now bringing our scientific expertise in hydrogen-materials technology to Austria, where a significant movement is taking shape. I am optimistic that Austria is on the path to becoming a global leader in both hydrogen energy and hydrogen materials technology. I have this strong intuition that we are here in Austria at a time of history where a Zeitgeist is being formed around hydrogen! Indeed, when a nation dares to dream big, everything falls into place!

Stay tuned for more news very very very soon!

Our destinity is in the stars.

– Stephen Hawking (1942-2018)