Reduction of radioxenon emissions from radiopharmaceutical facilities – A pilot study

The CTBT Organization is building an International Monitoring System (IMS) in order to verify that the state signatories of the treaty fulfil their commitments of not performing any kind of nuclear explosion. The atmospheric noble gas monitoring is a part of this verification system and focuses on the measurement of short-lived radioxenon isotopes in the atmosphere. In order to improve the sensitivity of the IMS noble gas network, the radioxenon background should be decreased. Previous research has shown that radiopharmaceutical facilities are responsible for the major part of the radioxenon background. In addition xenon releases from such facilities can hide the release of radiological more important nuclides. Reduction of radioxenon release will consequently decrease the global background and enhance the basic safety of such nuclear facilities. This study was centred on the Institut des Radioéléments (IRE) – the worldwide third largest 99Mo producer. Each production step was analysed to determine the amount and the isotopic composition of a possible xenon release. Many techniques were discussed in terms of performance and practical aspects for the reduction of xenon fission gas emissions. It has been demonstrated in this work that significant reductions of radioxenon discharges from 99Mo production facilities are theoretically possible.