Tritium permeation modelling in DEMO WCLL cooling system

Abstract

• Tritium permeation in DEMO represents a risk for safety and plant performance. • H 2 addition and CPS sizing in DEMO WCLL have strong impact on tritium release. • PRF barriers have to be taken into account to maintain tritium losses at acceptable levels. Tritium management is one of the most critical aspects in DEMO design. Knowledge of tritium permeation is a priority both in terms of safety and plant performance, as it may represent a radiological risk for the employed personnel and a significance loss of plasma fuel. Generally, high pressures and temperatures promotes the permeation phenomenon, which is mainly driven by partial pressure of tritium in gas phase and depends on system geometry, operative conditions and permeability of involved materials. This contribution presents a preliminary model for the calculation of partial pressures and tritium permeation flow rates inside the cooling system and the steam generator of a WCLL (Water Cooled Lead-Lithium) system. A parametric analysis was made to test the variation of key design parameters and preliminary results are shown.