The Chemical Kinetics of Alkaline Extraction of Tellurium from Lead-Bismuth Eutectic

Abstract

Developing the technology to remove neutron activation products from lead-bismuth eutectic requires understanding the chemical kinetics of the removal reaction. Polonium-210, an important radioactive product caused by neutron activation of lead-bismuth eutectic, poses a radiological hazard if a system breach occurred or system maintenance is performed. Methods to remove 210 Po have been discussed in the literature. One approach under consideration is to develop a system that would chemically remove 210 Po. The removal method under investigation in this research is alkaline extraction.Chemical kinetic measurements were made to determine first and second order rate constants and the activation energy at various temperatures using tellurium as a surrogate. First and second order alkaline extraction rate constants were measured to be: k 1 ¼2:17e À40;483=RT and k 2 ¼8:18e À74;018=RT where R is the ideal gas constant and T is the temperature in degrees Kelvin. Alkaline extraction is dependent on temperature and was found to follow the Arrhenius rate law. The activation energy (E a ) ranged between 40,483-74,018 JÁmol À1 . With a strong foundation of surrogate work completed, this work should be validated using 210 Po.