Plutonium Release from Burning Sodium

The release of PuO₂ from plutonium-contaminated burning sodium and liquid sodium under a nitrogen atmosphere has been measured. Also investigated was the release of β-Na₄PuO₅ from burning sodium. Plutonium concentrations in the initial sodium pool ranged from 13 to 250 ppm. Plutonium dioxide concentrations in the aerosol released from the burning sodium ranged from 5.6 to 1360 ppb. The PuO₂ released along with the sodium metal, when the sodium pool was heated in nitrogen at 540°C, varied from 67 to 3632 ppb. The release of β-Na₄PuO₅ from burning sodium was very small and could only be detected using nuclear track techniques and extended alpha counting. Aerosol particles followed a log-normal particle size distribution. The count mean diameter was 0.48 µm for PuO₂ and 0.98 µm for Na₂O_x.