Progress on Lithium Ceramic Breeder Materials Development, Characterization and R&D Activities in IPR

Full text: Several materials have been developed and being investigated for reliable and sustainable breeder candidate material. Lithium meta-titanate (Li₂TiO₃) and Lithium orthosilicate( Li₄SiO₄) are the prominent among the suitable candidate materials for breeders. India has proposed lithium meta-titanate (Li₂TiO₃) as the tritium breeder materials in the form of pebble bed for LLCB TBM. Li₂TiO₃ power was prepared by solid state reaction using LiCO₃ and TiO₂ followed by ball-milling and calcination. Li₂TiO₃ pellets and pebbles are prepared from this powder followed by high temperature sintering. Effect of sintering time and temperature on the properties of pebbles has been studied. At every stage of preparation, extensive characterizations are being carried out to meet the desired properties of these materials. The geometry and loading conditions of the breeder blankets makes the analysis complex. For a robust design of blankets requires a thorough understanding of the thermo-mechanical response of the breeder materials at different loading conditions. In this context, the material characterization plays a vital role in determining the breeder response. It is essential to measure the mechanical and thermo-mechanical properties of pebble bed. Experimental set ups have been built indigenously at IPR for the measurement of effective thermal conductivity of pebble bed using steady state-axial heat flow and transient hot wire methods. The effective thermal conductivity (k_eff ) of pebble beds is an important parameter for the design and analysis for a fusion tritium breeder blanket. The k_eff of Li₂TiO₃ pebble bed is measured as a function of average bed temperature from RT to 500°C in different environment (vacuum, helium gas, etc.). Initial results obtained from these experiments will be discussed in this paper. Details of lithium ceramic breeder material development, their characterizations and related R&D activities will be discussed in this paper. (author)