Abstract:
The aim of this work was to study resistance to helium accumulation processes in the
structure of the surface layer of lithium-containing ceramics and the subsequent destruction and
embrittlement processes, depending on radiation fluence. The objects of study were Li2TiO3
-type
ceramics obtained by thermal sintering. The fluence dependency of changes in the structural and
strength properties of ceramics was determined to be in the range from 1018 to 1022 ion/m2
, which
corresponded to the concentration of implanted helium from 0.01% to 0.8–1 at.%. Irradiation was
carried out at a temperature of 700 ◦C, which made it possible to simulate the processes of radiation
damage that were closest to the real conditions in the reactor core. During the studies carried out, it
was found that, at irradiation fluences of 1018–1020 ion/m2
, the formation of point radiation defects
was equaled by the process of thermal annealing of defects, as a result of which the concentration
of defects and their effect on the change in the structural and strength properties of ceramics were
insignificant. An increase in the concentration of implanted helium in the structure of the surface
layer to above 0.5 at.% led to the dominance of radiation damage processes over the annealing of
defects and the formation of gas-filled cavities, which negatively affects the strength of ceramics.
