Historical research guide · 0008 · 2025
Accessing Icy World Oceans using Lattice Confinement Fusion Fast Fission
Theresa L Benyo · Lawrence P Forsley · Rodger Dyson · Michael Becks
In one minute
NASA Glenn's Theresa Benyo, with Lawrence Forsley, Rodger Dyson and Michael Becks, asks how you power a robot that has to melt its way through twenty to forty kilometres of ice to reach the ocean under Europa or Enceladus. Their answer is a reactor with no enriched uranium and no plutonium-238 in it at all. Pack deuterium into a metal lattice, let the lattice's own electrons screen the positive charges so the nuclei can reach each other, and the fusion neutrons that come out are energetic enough to split depleted uranium or thorium — material that cannot sustain a chain reaction on its own. The team modelled the core in the Los Alamos Monte Carlo particle code and settled on deuterated depleted uranium ringed by beryllium and tungsten carbide: 59 kilograms, 12 kilowatts of heat, and about ten times the electrical power of the Kilopower reactor it is based on, with less shielding. Building and testing it is the next step.
Connection
This is chapter 12's design case: lattice confinement fusion used not as a curiosity but as the neutron source for a flight reactor, sized in kilograms and kilowatts, that needs neither enriched uranium nor plutonium. It is the first engineering answer to the thesis's claim that lowering the effective Coulomb barrier turns fusion from a confinement problem into a screening problem.
From the source
Lattice confinement fusion has been demonstrated by NASA, published in Physical Review C, and by Lawrence Berkeley National Laboratory, published in the Journal of Applied Physics, and commercialised by Astral Systems; both methods operate at much higher energies than any attempt at cold fusion.Introduction
A metal lattice holds deuterium at about 10^23 ions per cubic centimetre while the lattice electrons screen the positive charges, lowering the Coulomb barrier; triggered by a gamma beam or phonon-nuclear coupling this produces an equivalent local deuteron ion temperature of up to 3 keV, against 1.5 keV for the Sun.Lattice Confinement Fusion Fast Fission
Because lattice fusion neutrons carry more than 2 MeV, they can fast-fission non-fissile material — depleted uranium or thorium — so the reactor needs no highly enriched uranium, no HALEU, no LEU and no plutonium-238, and the fission products consume the neutrons that would otherwise demand shielding.Lattice Confinement Fusion Fast Fission Mechanisms
Work with the Naval Surface Warfare Centers has observed 90 to 200 watts-thermal per gram without actinides, against the 0.54 watt-thermal per gram of the plutonium-238 that powers radioisotope thermal generators.Lattice Confinement Fusion Fast Fission Mechanisms
Monte Carlo modelling selects a deuterated depleted uranium inner core with a depleted uranium-lithium outer core, beryllium and tungsten carbide reflectors and a stainless steel vessel: 59.2 kg of core, 12 kWth, and 4.2 kWe at 20 percent conversion — ten times the 420 We of the Kilopower reactor it is derived from, in a package 1.75 times smaller.Tables 2, 3, 4 and 5
The report states that while lattice confinement fusion has been demonstrated by both NASA and Lawrence Berkeley National Laboratory, a hybrid lattice fusion fast fission reactor still needs to be fully demonstrated, and that further study is required on shielding that would protect any lifeforms the probe encounters.Summary
The way in
https://ntrs.nasa.gov/citations/20260001675How to cite it
Theresa L Benyo, Lawrence P Forsley, Rodger Dyson, Michael Becks (2025) Accessing Icy World Oceans using Lattice Confinement Fusion Fast Fission https://ntrs.nasa.gov/citations/20260001675