Treatment of Low-Level Radioactive Waste by Plasma: A Proven Technology?

Abstract

Large amounts of actual and historical low level radioactive waste, with varying characteristics, are stored and generated from the operation and maintenance of nuclear power plants, the nuclear fuel cycle, research laboratories, pharmaceutical and medical facilities. Virtual all of these waste streams can be treated by the plasma technology resulting in a final product free of organics, liquids and moisture, and meeting without a doubt the acceptance criteria for safe storage and disposal. The plasma is a highly desirable heat source. Its high temperature of up to 10.000 °C can treat the radioactive waste as is. The inorganic materials are melted into a glassy slag, containing most of the radioactive isotopes, while the organic material is vaporized into a syngas and subsequently oxidized in an afterburner. This technology is very suitable for historical waste containing mixtures of inorganic, organic, liquids, sludge, etc, with almost no waste preparation and with minimal risk for radioactive contamination and exposure. Plasma technology offers a high volume waste reduction factor (VRF) that minimizes the volume and overall costs of waste storage and disposal. In addition, as plasma technology can recondition previously conditioned waste packages that no longer meet the present acceptance criteria for final disposal, it offers a solution to the growing demand for improved quality of final waste forms. As such, plasma technology is of great value, not just to waste producers but to future generations as well. This paper describes further the principles of plasma, the different waste feed systems, off-gas treatment, operational experience and future plasma plants.