REVERSIBLE AND IRREVERSIBLE HYDROGEN TRAPPING IN METALS - NEW COMPUTER-BASED CODE THYDA

Use of metallic materials for fusion reactor components and their perf ormance in the presence of hydrogen isotopes require a development of a physical transport model that permits to explain the dynamics of hyd rogen absorption and release. Trapping and release processes will stro ngly affect hydrogen isotopes inventories. The non-linear nature of hy drogen diffusion equations requires a numerical analysis. In this work a new computer code named THYDA was developed. In relation to thermal cycles, THYDA permits to calculate the concentrations of trapped and movable hydrogen atoms in metallic samples as well as hydrogen evoluti on rates during thermal desorption at elevated temperature with variab le heating rates. In these calculations it is possible to take into ac count both the internal and external sources of hydrogen isotopes (i.e . generation in (n, p) nuclear reactions and by D-T ion implantation).