Concrete and Metal Chemical Decontamination Methods for D&D Applications

Abstract

Radiologically contaminated concrete and metal surfaces pose a major challenge in nuclear demolition and decommissioning (D&D) projects. This is mainly due to the large volumes of solid radioactive wastes needing suitable management and disposal protocols. Contaminated surfaces can be a significant source term as well as a major dose contributor in highly contaminated sites, especially in post-accident environments.

Chemical decontamination methods are effective in reducing radiological contamination. Which in turn means that there is an overall reduction of solid waste volumes as well as exposure to site personnel. This results in higher worker efficiencies and improved ALARA goals, while reducing radiation protection and engineering controls. Particularly, when compared to conventional concrete scabbling or surface scrubbing techniques.

Recently, Westinghouse has successfully completed a series of decontamination projects in the United States and Europe, where the efficacy of a chemical process to remove contamination from various substrates, including concrete, metal and polyurethane/polyurea, has been demonstrated. The process utilizes several proprietary agents and tools in varying sequences to achieve the desired results.

This paper will further discuss the above-mentioned processes and will provide an overview of the used agents as well as their application to varying site conditions. Further, it will address potential owners’ concerns such as secondary waste streams and their management. The authors will present results from recently completed projects and will explore potential applications at Canadian nuclear sites.