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大釜 和也; 大木 繁夫; 北田 孝典*; 竹田 敏一*
Proceedings of 21st Pacific Basin Nuclear Conference (PBNC 2018) (USB Flash Drive), p.942 - 947, 2018/09
A core concept of minor actinides (MAs) transmutation with improved safety was designed by applying sodium plenum and axially heterogeneous configuration. In this study, heterogeneous MA loading methods were developed for the core concept to explore the potential of further improvement of MA transmutation amount and "effective void reactivity" which was introduced by assuming the axial coolant sodium density change distribution for the unprotected loss of flow accident. By investigating characteristics of heterogeneous cores loading MA in different radial or axial positions, preferable MA loading positions were identified. The core loading MA in the radial position between inner and outer core region attained the largest MA transmutation amount and lowest maximum linear heat rate (MLHR) among heterogeneous cases. The lower region of the core was beneficial to improve the effective void reactivity and MLHR maintaining the nearly same MA transmutation amount as that of the homogeneous core. The radial blanket region was also useful to increased MA transmutation amount without deterioration of the effective void reactivity.
Ti)O
ceramics fabricated by high-pressure sintering北田 和也*; 小舟 正文*; 足立 渉*; 矢澤 哲夫*; 齋藤 寛之; 青木 勝敏; 水木 純一郎; 石川 健哉*; 平永 良臣*; 長 康雄*
Chemistry Letters, 37(5), p.560 - 561, 2008/05
被引用回数：9 パーセンタイル：37.59(Chemistry, Multidisciplinary)Bi(NiTi)O ceramics with a perovskite structure was synthesized at a high pressure of 6 GPa. It was confirmed that the synthesized samples had a multidomain structure and ferroelectricity on the basis of scanning nonlinear dielectric microscopy (SNDM) and polarization-electric field (P-E) hysteresis loop measurements.
Ti)O齋藤 寛之; 北田 和也*; 小舟 正文*; 足立 渉*; 矢澤 哲夫*; 石川 健哉*; 平永 良臣*; 長 康雄*; 青木 勝敏
no journal, ,
Ferroelectric lead zirconate titanate is widely used as integral parts of electrical devices due to the high dielectric and electromechanical properties. However, the toxicity of lead oxide results in serious environmental problems and hence alternative compounds free from lead are urgently under development. Since Bi
ion has the same electronic structure as the Pb
ions, Bi-containing perovskites are promising candidates for lead-free ferroelectric ceramics. Bi(NiTi)
, BNT, ceramic was synthesized using reagent-grade Bi
O, TiO and NiCOnHO as starting materials. A mixture of the starting materials was calcined in air and then grounded to fine powder to fill up densely a high-pressure reaction cell. The sample was initially compressed and successively heated on keeping constant pressure. The single-phase perovskite structure was formed. P-E hysteresis loop shows that the BNT ceramic is ferroelectric. A multi domain structure of the BNT ceramic was also measured by scanning nonlinear dielectric microscopy.
大釜 和也; 大木 繁夫; 北田 孝典*; 竹田 敏一*
no journal, ,
核変換量と安全性に係わる反応度係数の調和を考慮したMA核変換炉心概念を開発している。本研究では、炉心上部にナトリウムプレナムを設置するボイド反応度低減方策を用いたMA核変換炉心概念をもとに、径方向および軸方向に非均質にMAを装荷した場合の炉心特性およびMA核変換量のMA装荷位置依存性を評価し、実効ボイド反応度およびMA核変換量等において有利な装荷方法について検討した。また、MA核変換量向上のため、Zr-H減速材付MAターゲットの適用性について検討した。
