Colibri HTR 3, an Advanced Fuel Coating Irradiation. Part 1: Principles and Preparation

The previous experiment in the OSIRIS ''Colibri'' rig, HTR 2, contained a ''geometrical'' sequence of fuel particle coatings derived from methane. HTR 3 involves a wider variety in which the pyrocarbon source gas includes butane and propene. A similar series is being irradiated in the RAPSODIE reactor at Cadarache with an emphasis on fast neutron effects but in Colibri both fast dose and burn-up will exceed the requirements of a power reactor. Part I of this report sets out the principles behind the particle design, the detailed pre-irradiation data, the arrangement of the fuel varieties in the rig, and a proposed programme of examination. (author)