Diffusion Behavior of Cesium, Strontium and Cobalt in Pellet Waste Package

Abstract

A leaching model for a radioactive pellet package for nuclear power plant wastes was studied. Calculated results obtained in term of the model were compared with experimental ones, where volumetric averages of diffusion coefficients in the Na₂SO₄ pellet and in the cement-glass were used to solve the diffusion equation in the pellet package. Since Na₂SO₄ pellets dissolved quickly, the pellet part were simulated by saturated Na₂SO₄ solution. The leaching ratios were meaured with different volume ratios of cement-glass in the package to discuss the validity of the model. The cement glass diffusion coefficient and distribution factor, which were required to solve the equation, were also measured. The calculated results agreed with the experimental ones within a 20% error.

KEYWORDS:

• radioactive waste
• waste package
• waste processing
• solidification
• leaching
• diffusion model
• pellets
• sodium sulfates
• cement-glass
• diffusion coefficient
• distribution factor
• cesium
• strontium
• cobalt