A Semi-Automated Metal Decontamination and Recycling Process

摘要

A semi-automated and patented process for decontaminating and recycling radioactively contaminated heat exchanger tubes has been successfully demonstrated at the Ignalina nuclear power plant in Lithuania. Low-level radioactive waste burial volumes and disposal costs are reduced by supplying the clean, surveyed metal strips for industrial reuse. Nuclear plants employ tubular heat exchangers in which the reactor core's heat energy - in the form of steam used to power a steam turbine-generator system - is condensed and returned to the reactor core without coming in direct contact with the recirculated cooling water. Tubular heat exchangers are typically made of copper alloys, in which copper often constitutes greater than 90% of the mass. Benefits include high thermal conductivity; ductility and toughness over a wide range of temperatures; and corrosion resistance. This ensures the tubes maintain a stable and durable shape. However, these tubes tend to absorb and trap radionuclides in a shallow oxide film. This accumulated contamination is very difficult to remove while the plant is in operation.