Self-irradiation effects in plutonium alloys stabilized in the δ-phase

Abstract

Plutonium aging leads to the creation of decay products, such as americium, uranium, helium, but also to selfirradiation defects such as vacancies and interstitials. These self-irradiation defects can affect the properties of plutonium; as an example, swelling of PuGa or PuAI alloys has been observed at room temperature. This work is devoted to the study of the effect of aging on the magnetic susceptibility of pure and alloyed plutonium. An anomaly has been revealed at low temperatures (T < 75K) for magnetic fields lower than 4.5 T. This anomaly decreases after heat treatment. A tentative explanation, based on results from molecular dynamics calculation in 8-plutonium, is given to explain the origin of the anomaly.

Study by XRD of the lattice swelling of PuGa alloys induced by self-irradiation

“…The difference of lattice swelling under self-irradiation suggests that some electronic effects could eventually contribute to the lattice swelling. Besides, a change of electronic structure during self-irradiation was already observed through magnetic susceptibility measurements performed at low temperature on plutonium-gallium and plutonium-americium alloys [31,32]. Moreover, resonant photoemission experiments performed on a new and aged plutonium-gallium alloy stabilized in the d-phase suggested differences particularly at the Fermi level which has a strong 5f character [33].…”

Final Report for Plutonium and Quantum Criticality LDRD 03-ERD-077

“…7 shows the magnetic isochronal annealing results for δ-Pu 1-x Am x (x = 0.224) where the damage was accumulated at sufficiently low temperatures that once formed, the damage cascades are frozen in place. Previous work on radiation damage in PuAm alloys has also investigated the consequence of damage on magnetic susceptibility, but such damage was accumulated near room temperature [45,46] which as may be observed in Fig. 7, is very close to the annealing stage where small vacancy clusters are unstable.…”

Isochronal annealing studies in Pu and Pu alloys using magnetic susceptibility

“…2 shows the EMS annealing results for ␦-Pu 1−x Am x (x = 0.224) where the damage was accumulated at sufficiently low temperatures that once formed, the damage cascades are frozen in place. Previous work on radiation damage in PuAm alloys has also investigated the consequence of damage on magnetic susceptibility, but such damage was accumulated near room temperature [16,17], which as shown in Fig. 2, is very close to the annealing stage where small vacancy clusters are unstable.…”