Abstract
The safe and cost-effective decommissioning of legacy nuclear sites relies on accurate measurement of the radioactivity content of the waste materials, so that the waste can be assigned to the most appropriate disposal route. Such measurements are a new challenge for the science of radionuclide metrology which was established largely to support routine measurements on operating nuclear sites and other applications such as nuclear medicine. In this paper, we provide a brief summary of the international measurement system that is established to enable nuclear site operators to demonstrate that measurements are accurate, independent and fit for purpose, and highlight some of the projects that are underway to adapt the measurement system to meet the changing demands from the industry.