Speaker
Maria Gonzalez
(LNF-DTF)
Description
The tritium release behaviour of candidate ceramic materials for the HCPB breeder concept is still an issue. High experimental costs, long experimental periods, and handling difficulties for activated materials after being tested in experimental fission reactors have motivated the validation of alternative methods for testing the gas desorption behaviour of tritium breeder materials. In the framework of EUROFusion, desorption experiments are being performed during irradiation by means of accelerated electron and ion beams to simulate the electronic and structural changes induced in breeder ceramics due to neutron radiation. The aim of this four year study is two fold: an understanding of the diffusion and release phenomena which take place in a ceramic pebble bed, and the efficiency of these radiation sources will be validated for a DEMO-like simulated environment.
Deuterium desorption results for advanced lithium orthosilicate pebbles, mechanically improved by additions of lithium metatitanate (developed at KIT) are presented here. Pebble beds of different composition were first deuterium loaded under ionizing radiation and breeder temperature operational conditions, and then thermally induced gas desorption recorded during heating. The experimental results indicate that the gas release is more efficient when the pebble bed is loaded at temperature and under irradiation. Furthermore the observed enhancement of deuterium desorption efficiency has been attributed not only to the ionizing radiation, but also to the increase of surface roughness, which changes with the addition of the reinforcing second phase, lithium metatitanate. Fusion operational conditions in advanced breeder blanket ceramics will then facilitate the release of the tritium produced due to lithium transmutation reaction.
Co-authors
Alejandro Morono
(LNF-DTF, CIEMAT, Madrid, Spain)
Elisabetta Carella
(LNF-DTF, CIEMAT, Madrid, Spain)
Eric R. Hodgson
(LNF-DTF, CIEMAT, Madrid, Spain)
Maria Gonzalez
(LNF-DTF, CIEMAT, Madrid, Spain)
Marta Malo
(LNF-DTF, CIEMAT, Madrid, Spain)
Matthias H.H. Kolb
(Institute for Applied Materials (IAM-KWT), Karlsruhe Institute of Technology, Karlsruhe, Germany)
Regina Knitter
(Institute for Applied Materials (IAM-KWT), Karlsruhe Institute of Technology, Karlsruhe, Germany)