PNNL

Abstract

Volatile radioisotopes represent a substantial health risk when released into the environment. To better understand the environmental fate of radioisotopes, the authors constructed a cylindrical steel-walled chamber constructed to simulate the atmospheric photooxidation and processing of volatile radioactive gases. Optical modeling was performed to understand the distribution, intensity, and homogeneity of simulated sunlight introduced into the chamber with the goal of better characterizing atmospheric reaction studies in the chamber. Optical simulations were performed using two wall materials (steel, and thin-film silica) and validated against experimental measurements. In cases where optical irradiance is a rate-limiting factor for photooxidation reactions this optical model can be used to improve the fidelity of atmospheric models by accounting for optical inhomogeneities enabling a firmer grasp of isotopes’ environmental fate.