Finding the depth of radioactivity in construction materials

Abstract

A key challenge in disposing of nuclear legacy facilities and planning a new nuclear plant is how to assess the extent or likelihood of radioactive contamination in construction materials and the ground. This paper summarises the status of two techniques based on the analysis of emitted radiation from materials that comprise such structures, and describes how this analysis can be used to infer the depth of contamination without the need to penetrate the structure or to destroy it in the process. Two experimental facilities have been developed to test the efficacy of these techniques, and data are provided for the most widespread contaminant experienced in the sector: caesium-137.Finally, the influence on the technique of the likely variety of silica-based media to be encountered in the nuclear industry is described, together with a summary of challenges to be addressed in future research. Notation ddepth in the material E photon energy I(x) intensity of the radiation I(0)intensity at x ¼ 0 R 0 and R X/g ratios of the counts in the X-ray and g-ray photopeaks at zero depth and depth d x thickness of material x and y constants and w is a function of an angle u derived between successive principal components derived at increasing depths m(E) attenuation factor m X and m g attenuation coefficients for the X-ray and the g-ray, respectively

Editorial

“…Another paper relating to construction materials and decommissioning (Joyce et al, 2013) addresses the complex problem of identifying the extent to which these materials are contaminated. Construction materials such as concrete (or the ground itself ) are by definition porous and, when used in nuclear facilities, have the potential to become contaminated.…”