Activation analyses for the IFMIF-Liquid Breeder Validation Module (LBVM)

Abstract

The Liquid Breeder Validation Module (LBVM) will be one of the medium flux irradiation modules of the International Fusion Materials Irradiation Facility (IFMIF) neutron source. The objective of this module – presently under design – is the test of functional materials related to liquid breeders for future nuclear fusion power reactors (DEMO). This paper aims to describe the activation analyses performed to estimate the radioactive inventory and the expected contact dose from the activated materials of the module following a 345 day irradiation period. These calculations supply valuable information for different aspects related to the design of the module, such as the safety evaluation and the waste management and disassembly plan.The neutron transport calculations have been performed using the McDeLicious code. The ACAB nuclear inventory code, with the activation nuclear libraries EAF-2007, has been used for the activation analyses.The main results point out that the contact dose of the LBVM materials is much higher than the hands-on-limits, as expected. Therefore, remote handling operations are requested for disassembling the module. It is important to remark that after 8h decay time, the contact dose rate of the LBVM decreases 76% for the EUROFER steel components and 46% for the 316LN components. Regarding the isotopic inventory, although the main activation comes from the module steel structures, the production of tritium and Po-210 in the lithium lead inside the experimental capsules deserved a careful analysis.