Compatibility of advanced tritium breeders and neutron multipliers

•Compatibility tests between advanced tritium breeders and neutron multipliers were performed at 973, 1073 and 1173 K.•A reaction layer with a thickness of less than a few μm at 1073 K or 1173 K for 100 h formed on the Be12V surface.•Be12V in contact with LTZO had a reaction layer whose growth rate was considerably lower than Be in contact with LTZO. A new blanket concept of demonstration (DEMO) fusion reactors has been suggested using a mixture of tritium breeders and neutron multipliers. This concept requires long-term stability between tritium breeders and neutron multipliers. To verify the feasibility of the mixing pebble packing concept, compatibility tests of Li-access Li2+xTiO3+y with 20 % Li2ZrO3 (hereinafter referred to as LTZO) and Be12V as an advanced tritium breeder and neutron multiplier, respectively were performed at 973 K, 1073 K, and 1173 K for 100 h, 300 h, and 1000 h, respectively. Cross-sectional scanning electron microscopic observations and X-ray diffraction (XRD) analysis revealed that Be oxides (Li with small intensity) were formed on the surface of Be, however, no reaction layer or a very thin layer was identified. Clarity was received that as the time at each temperature increased, the thickness tended to increase. The thickness of the reaction layer could be described by a parabolic rate law. The conclusion was reached that Be12V in contact with LTZO had a reaction layer whose growth rate was considerably lower by one order of magnitude than that of Be in contact with LTZO.