Radioactive Technetium-99 Discharges from Sellafield

Publication date: December 2002

Summary
Tc-99 is formed by the fission of uranium and plutonium when uranium is used as fuel in nuclear power stations; it does not occur in nature. Tc-99 has a half-life (i.e. the time taken for half of its activity to radioactively decay) of 213,000 years. The annual arisings of Tc-99 from the reprocessing of spent Magnox fuel in the Magnox reprocessing plant and the reprocessing of spent oxide fuel in the Thermal Oxide Reprocessing Plant ("THORP") that are currently destined for discharge to sea are around 30 - 40 TBq (Terabecquerels) and less than 1 TBq respectively.