MAIN RESULTS OF THE ANALYSES RELATED TO A FEW REFERENCE ACCIDENT SEQUENCES OF NET ITER TRITIUM SYSTEMS

Based on the existing conceptual design, a set of Reference Accident S equences (RAS) has been defined by tritium system experts. This paper presents the main results related to a preliminary analysis of the fol lowing RAS for fuel cycle systems: hydrogen detonation in the isotopic separation system, rupture of a cryoline in a cryopump, fire in the l ong-term storage beds, and mechanical faulty operation in the pellet i njector. The systems and the component mode of operation have been ana lyzed, as well as the characteristics of all streams, the inventory of T, D, and H, and the energy released under accident conditions. Failu res that could give rise to the release of tritium and/or to the forma tion and ignition of oxygen/hydrogen mixtures and failures that could lead to containment pressure transients are discussed and examined.