In the present work, we use DFT calculations to determine hydrogen adsorption energies ranging from low to high surface coverage on low-index facets on δ-Pu. We first use a simple two-state model to discuss relevant hydrogen surfaces coverages in terms of adsorption energetics when P H 2 ≈ P eq H 2 . This simple model helps place bounds on the numbers and types of adsorptions and their resulting energies that are likely relevant to initiating surface hydriding on different crystalline facets. We quantify bulk absorption of hydrogen in δ-Pu and PuH 2 at varying hydrogen concentrations, including the formation of point defects in PuH 2 .