SOME STUDIES OF AEROSOLS PRODUCED BY COMBUSTION OR VAPORIZATION OF PLUTONIUM-ALKALI METAL MIXTURES .I.

Experiments are reported in which aerosols were generated by either the combustion or the sudden vaporization of plutonium-sodium mixtures. In the combustion experiments it was found that in general the airborne release was little affected by the presence of the sodium, although in one case a higher release occurred. The properties of the residue were of interest in that after extraction with water a large proportion of the plutonium (1% to 5%) was apparently soluble, a colloidal suspension of fine particles being formed. It was found that even sodium hydroxide or sodium peroxide, if present during the ignition, could induce formation of a large colloidal plutonium fraction after extraction with water. The exploding wire experiments were more reproducible. Here it was found that the aerosol was changed by the presence of the sodium from chains of submicron spheres to a narrow distribution of particles having a mass median diameter of about 1.4 μm. On extraction with water these disintegrated to a stable colloidal suspension in which about 40% of the plutonium was present as particles of diameter less than 50 Å. The sodium-plutonium aerosol was dark brown in colour, and its reactions with water vapour indicate the possibility of a new chemical species of plutonium. It was also found that vaporization of plutonium with sodium hydroxide or sodium peroxide resulted in the formation of limited amounts of the colloidal material after extraction with water. Coagulation experiments indicated that the colloidal material was negatively charged. This result was confirmed by electrophoresis experiments. © 1969.