Fabrication and characterization of Li-enriched LiTiO pebbles for a high Li-burnup irradiation test
高Li燃焼照射試験のためのLi濃縮LiTiO微小球の製造と特性評価
土谷 邦彦 ; 河村 弘
Tsuchiya, Kunihiko; Kawamura, Hiroshi
チタン酸リチウム(LiTiO)微小球は、低い温度(約300C)における容易なトリチウム放出及び化学的安定性の観点から核融合炉のためのトリチウム増殖材料の候補材料として考えられている。本研究では、直径1mmのLi濃縮LiTiO微小球の試作試験を脱水反応を利用した湿式法(脱水型ゲル化法)により行い、試験炉を用いた高Li燃焼照射試験の準備のために、Li濃縮LiTiO微小球の特性を評価した。96at%のLi濃縮度を有するLiTiO粉末を固相反応により調整し、TiOの無添加のものとTiOを添加したものの2種類のLiTiO微小球を湿式法により製作した。微小球製造試験の結果に基づき、目標値(焼結密度: 80-85%T.D.,結晶粒径: 5m以下,直径: 0.851.18mm)を有する2種類のLi濃縮LiTiO微小球を製造することに成功した。また、これら2種類の物理的,化学的及び機械的特性を評価し、これらのLiTiO微小球の真球度が約1.05、微小球の接触強度が約6300MPa等の特性データを取得した。
Lithium titanate (LiTiO) pebbles are considered to be a candidate material of tritium breeders for fusion reactor from viewpoints of easy tritium release at low temperatures (about 300) and chemical stability. In the present study, trial fabrication tests of Li-enriched LiTiO pebbles of 1mm in diameter were carried out by a wet process with a dehydration reaction, and characteristics of the Li-enriched LiTiO pebbles were evaluated for preparation of a high Li-burnup test in a testing reactor. Powder of 96at% Li-enriched LiTiO was prepared by a solid state reaction, and two kinds of Li-enriched LiTiO pebbles, namely un-doped and TiO-doped LiTiO pebbles, were fabricated by the wet process. Based on results of the pebble fabrication tests, two kinds of Li-enriched LiTiO pebbles were successfully fabricated with target values (density : 80-85%T.D., grain size : 5m, diameter : 0.85-1.18mm). Physical, chemical and mechanical properties of these pebbles were also evaluated before neutron irradiation tests. Sphericity of these LiTiO pebbles was a satisfying value of about 1.05. Contact strength of these pebbles was about 6300MPa, which was almost the same as that of the LiTiO pebbles with natural Li.