Plutonium's unique material properties make it useful as a heat source in power plants and in radioisotope thermoelectric generators. 1 However, plutonium is highly reactive and will corrode if exposed to atmospheric gases, even in trace amounts. Hydriding in face-centered cubic (fcc) δ-Pu occurs if the hydrogen concentration exceeds a temperature-dependent solubility limit. As it incorporates hydrogen to form plutonium dihydride (PuH 2 ), the plutonium lattice expands by approximately 60 volume %, causing cracks and fissures in the plutonium surface. Moreover, PuH 2 is pyrophoric, catalyzing rapid, violent exothermic oxidation. As a result, uncovering the mechanisms by which plutonium corrodes can improve safety regulations and eliminate toxic waste.