It is proposed to assist and substantially increase the production of Plutonium 238 by inertial fusion inside a pipe made of stainless steel passing through the core of a conventional nuclear fission reactor, by injecting a stream of pellets of Neptunium 237 encapsulated liquid deuterium–tritium (DT) under high pressure. Then, if from both ends of the pipe, a pulse of multi-megajoule intense relativistic electron beams are injected, they will compress the pellets and heat the liquid DT to reach ignition, leading to a smoldering thermonuclear burn, releasing a burst of 14 MeV neutrons, converting the Neptunium 237 into Neptunium 238, which after leaving the pipe outside the reactor, will by radioactive decay be converted into Plutonium 238. This strategy permits that the surplus of neutrons are not lost, because they are absorbed in the bulk of the fission reactor and not lost into the environment.
