Production of Low-Density Aerogel Nuclear Fuels for Use in Fission Fragment Rockets and Novel Reactor Design

TL;DR

This paper reports the creation of ultra-low density graphene aerogel nuclear fuels loaded with uranium or thorium, enabling high-energy ion escape and potential applications in space propulsion, modular reactors, and medical therapeutics.

Contribution

It introduces a novel low-density graphene aerogel nuclear fuel fabrication method with enhanced alpha activity and fission capabilities for advanced nuclear applications.

Findings

Aerogels had densities of 0.018-0.035 g/cm3.

Alpha activity could be increased to ~49 pCi/mg.

Fission induced by high energy neutrons demonstrated.

Abstract

Graphene hydrogels were created and loaded with uranyl nitrate or thorium nitrate and freeze-dried to produce graphene aerogel nuclear fuels. These aerogels had densities between 0.018-0.035 g/cm3 and consisted of ~7.3 +- 0.5% uranium/thorium by mass. The ultra-low density of the aerogels allows for high energy ions to escape the fuel particles without depositing all their energy as heat, as is typical in nuclear fuels. Their measured alpha activity was ~16 pCi/mg, which could be enhanced up to ~49 pCi/mg by decreasing the thickness of aerogel samples to allow all alpha particles to escape. Additionally, high energy neutrons were used to induce fission to provide a source of fission fragments from the aerogel fuels. This novel form of nuclear fuel has potential applications in space propulsion such as fission fragment rocket engines, as well as in terrestrial applications for modular reactors, direct conversion methods, and in medical radiotherapeutics.