The Impact of Long- Lived Particulates on the Pickering NGS Retubing Program

Abstract

In March 1984, Pickering site staff commenced the long task of rehabilitating the Unit 1 and 2 reactors. The initial stages of the project were notable for several remarkable accomplishments in radiation field reduction and innovative measures in niinimizing dose consumption. The project took an unexpected turn in March 1985, when it was realized that vault work activities were giving rise to contamination control difficulties. The normal multiple barrier approach to contamination spread was inexplicably failing. The source of the problem was quickly identified. It proved to be a unique radiological hazard - a low energy beta emitter without the presence of the more familiar radionuclides like cobalt-60 and cesium-137. It was found to be carbon-14 in a particulate form. This paper discusses the origin and nature of the particulate hazard, workplace hazard controls, protective equipment contamination monitoring and dosimetry for this radionuclide.