Working with plutonium fuels in a beta-gamma laboratory

Commissioned in 1961, the High-Activity Analysis and Measurement Laboratory (LAMA) was designed for the purpose of examining irradiation devices from experimental reactors at the Grenoble Nuclear Research Centre. LAMA comprises a line of concrete-walled cells affording protection against 100,000Ci of 1-MeV γ-radiation, and a number of hot laboratories equipped with lead-walled cells. Work has been in progress since 1969 on the possibility of examining devices containing plutonium. Of particular value in this connection was the experience gained in examining highly irradiated UO2 fuels, which showed that the containment was fully effective. Hazard evaluation studies indicate that accidental plutonium contamination can always be detected from the associated β-γ contamination, provided that certain fuel irradiation and cooling conditions are fulfilled. Modifications have been carried out on the cells intended for irradiated plutonium, and include enhanced leak-tightness and improved handling facilities through provision of special equipment, reinforced ventilation of the line of test cells, and introduction of fresh safety devices. Notwithstanding the improved levels of containment, additional precautions are applied within the shielded areas to limit contamination, and external checks are carried out during operations involving plutonium. In addition, more rigorous operating rules have come into force. The experience acquired shows that, at quite low cost and in return for a few additional constraints, it is possible to adapt a β-γ laboratory for work with irradiated plutonium. (author)