Measurement of Thermal Diffusivity of Li₂TiO₃ Pellets By the Laser Flash Method and Comparison With Finite Element Simulation

Lithium metatitanate (Li₂TiO₃) is one of the candidate tritium-breeder materials for the ITER test blanket module (TBM) and the DEMO blanket. It will be used as the tritium-breeder material for the Indian lead-lithium–cooled ceramic breeder concept of the TBM to be tested in ITER. Thermal conductivity is one of the most important parameters in the design of TBMs using ceramic materials. The design of breeder blankets is strongly affected by the low values of the thermal conductivity and density of ceramic breeder pebble beds. A significant increase in both quantities would enhance thermal performance and lead to an increased tritium-breeding ratio. Thermal transport properties of Li₂TiO₃ were measured using the laser flash method, which determines the thermal diffusivity from the transient temperature rise measured at one side of a pellet with laser pulse heating at the other side. The thermal conductivity of Li₂TiO₃ pellets was then estimated from the experimentally obtained thermal diffusivity values. Finite element analysis using ANSYS software was performed to simulate the transient thermal measurements, and the results were compared with those obtained by the laser flash method. The experimental and simulation results were found to be in good agreement. The experimental details and ANSYS simulation are presented in this paper.