Study on characterization of ceramic materials for nuclear engineering

Ceramic materials are very important in nuclear engineering。They have such complicated textures that gas transport process through them is not easy to understand.The aim of this study was to measure the structure and the characterisitics of adsorption and the gas permeation in order to clarify the relationship among them on fusion reacter blanket materials.This study was performed in the following themes：1.Gas permeability and pore structure of sintered lithium fluoride(LiF).As a syhaving weak interaction between permeating gas and sintered matrix，a pair of LiF and Ar-He gas mixure as characterisitics of adsorption and pars.It was shown that they can be expressed by a simple function of porosity in the matrix determined by a mercury porosimeter.2。Adsorption of H_2O on Li_2O and equilibrium vapor pressure of H_2O in the system of Li_2O-LiOH mixture.Adsorption amount of H_2O on lithium oxide(Li_2O)samples with various sizes of apparent particle radius as well as its enthalpy change was measured to investigate the chemical interaction of permeating gas and sintered matrix.In addition，equilibrium vapor pressure of H_2O in the system of Li_2O-LiOH mixture was obtained in high accuracy in the wide temperature range of 350-620°c.3。Estimation of tritium inventory in fusion reactor blanket.Computational code to calculate tritium transport in fusion reactor blanket was constructed in order to estimate the tritium inventory of RFP-type fusion reactor.In this code，some data obtained in this study swre utilized，and its availability and importance were recognized.The final report on this project has been published.

Ceramic materials are very important in nuclear engineering. They have such complicated textures that gas transport process through them is not easy to understand. The aim of this study was to measure the structure and the characterisitics of adsorption and the gas permeation in order to clarify the relationship among them on fusion reacter blanket materials.This study was performed in the following themes:1. Gas permeability and pore structure of sintered lithium fluoride(LiF).As a system having weak interaction between permeating gas and sintered matrix, a pair of LiF and Ar-He gas mixture was chosen, and the gas permeability and the diffusity through LiF samples prepared in various sintering condition. It was shown that they can be expressed by a simple function of porosity in the matrix determined by a mercury porosimeter.2. Adsorption of H_2O on Li_2O and equilibrium vapor pressure of H_2O in the system of Li_2O-LiOH mixture.Adsorption amount of H_2O on lithium oxide (Li_2O) samples with various sizes of apparent particle radius as well as its enthalpy change was measured to investigate the chemical interaction of permeating gas and sintered matrix. In addition, equilibrium vapor pressure of H_2O in the system of Li_2O-LiOH mixture was obtained in high accuracy in the wide temperature range of 350-620゜c.3. Estimation of tritium inventory in fusion reactor blanket.Computational code to calculate tritium transport in fusion reactor blanket was constructed in order to estimate the tritium inventory of RFP- type fusion reactor. In this code, some data obtained in this study swre utilized, and its availability and importance were recognized.The final report on this project has been published.