Measurement of the plutonium hold-up in a melting furnace at CEA Bruyeres-Le-Chatel

The Bruyeres-Le-Chatel research center is going through a period of dismantling and clean-up. Some equipment cannot be moved and are dismantled in situ. We need to evaluate the quantity of fissile materials to prevent criticality risk and to manage waste production. A melting furnace was dismantled. Measurements by gamma spectrometry (with an HPGe detector) and passive neutron counting (coincidence counting with shift register) are done in situ (furnace in the gloves box) and the 100-L and 200-L drums produced during the dismantling were also measured. Based on simplified assumptions to analyze in situ measurements, plutonium weight could be evaluated. The results show good agreement between in situ and waste measurements.