Design of a multi-isotopic hydrogen co- and counter-permeation experiment for HCPB related tritium mitigation studies

Abstract

A safe operation of the HCPB breeding blanket requires tritium permeation from the breeder into the coolant to be kept as low as possible. Previous studies could identify co- and counter-permeation of different hydrogen isotopes as a method to affect the permeation fluxes of the involved species. For the investigation of multi-isotopic transport as a permeation mitigation or enhancement mechanism in an HCPB related environment a new permeation experiment has been designed in which tritium is substituted by deuterium. It consists of two gas cavities inside of a vacuum chamber separated by a EUROFER sample disk that can be heated to temperatures of up to 600 . The set-up allows injecting arbitrary partial pressure combinations of and into each chamber. Co- and counter-permeation processes can be analysed for different temperatures and pressure configurations by measuring the occurring deuterium permeation fluxes using a calibrated quadrupole mass spectrometer. Apart from the determination of characteristic hydrogen isotope transport coefficients of the sample material the presented experiment is designed to serve as a validation tool for existing multi-isotopic transport models which are used to explain and simulate co- and counter-permeation effects in breeding blankets.