Investigating the Permeability of Hydrogen Isotopes through High Z Materials

Abstract

Due to its aneutronic properties, the combination of deuterium and helium-3 (D-He3) is being studied as potential fuel for nuclear fusion as D and He3 react to produce high energy helium isotopes that can be extracted for electric power. However, deuterium in the fuel can react with itself and produce tritium, a radioactive H isotope that if left in the plasma, reacts with deuterium to produce high energy neutrons that sputter metal atoms from the reactor’s walls, damaging the reactor and weakening the plasma. The objective of this thesis is to aid in the evaluation of Palladium as a candidate material for the proposed ZBZ sandwich structure for tritium removal at the exhaust stream of a reactor. To do this, a detailed investigation on deuterium permeation through Pd was conducted, varying conditions, such as Pd temperature, ion energies and fluence, to study each parameter’s effect on the permeability of Pd. Additionally, this study expanded upon previous work on deuterium permeation through the Pd foil by determining the principal species of deuterium in Pd permeation. The study determined that deuterium permeation is not only temperature dependent and dominated by D atoms but also has a negative correlation with rising nitrogen fluence through Pd foil, showing that at low temperatures of 200 oC, D permeation decreases as nitrogen implantation in the Pd sample increases.