検索対象:     
報告書番号:
※ 半角英数字
 年 ~ 
 年

Prevention of segregation of pore former by granulating with MOX powder in low density pellet fabrication for fast breeder reactors

高速増殖炉用低密度ペレット製造におけるMOX粉末との造粒による密度降下剤の分離防止について

村上 龍敏 ; 青野 茂典

Murakami, Tatsutoshi; Aono, Shigenori

原子力機構では、高速増殖炉もんじゅのMOX燃料製造技術の開発を行っている。MOX燃料ペレットは、原料となるMOX粉末をタブレット造粒法により造粒した後、圧縮成型,焼結して製造する。高速増殖炉もんじゅ燃料ペレットは、低密度仕様であるため、MOX粉末に有機添加物である密度降下剤を添加・混合して製造する。ペレットに含まれる密度降下剤は、焼結中に熱分解し、MOXペレット中に気孔を形成させる。従来、密度降下剤は、造粒粉末に添加・混合していたが、密度降下剤の比重がMOX粉末に比べ非常に軽いため、MOX粉末中に偏析し、燃料ペレットの密度のばらつきが大きくなるという問題があった。このため、造粒前の粉末に添加・混合し、造粒粉末内に密度降下剤を閉じ込めることとした。この結果、密度降下剤の偏析が抑制され、密度のばらつきが小さくなった。

Japan Atomic Energy Agency has been working to advance fabrication technology of mixed plutonium-uranium oxide fuel pellets for fast breeder reactors. In brief, the usual fabrication method of MOX pellets for FBRs consists of granulating raw MOX powder by a tabletting method, followed by pressing into compacts. Then, the compacts are sintered to get the MOX pellets. For the FBR "MONJU", MOX pellets having low density are required as the fuel pellets. The low density pellets are fabricated by adding an organic additive called a "pore former" to the MOX powder. The pore former is thermally decomposed and pores are incorporated into MOX pellets by sintering the compacts containing the pore former. In the past, the pore former was blended with the granulated MOX powder after the granulation process. But the pore former became segregated from the granulated MOX powder during feeding to the press machine, because the specific gravity of pore former is significantly lower than that of granulated MOX powder. In order to solve the problem, blending the raw MOX powder with the pore former was carried out before the granulation process to keep the pore former in the granulated MOX powder. As the result, segregation of pore former was prevented.

Access

:

- Accesses

InCites™

:

Altmetrics

:

[CLARIVATE ANALYTICS], [WEB OF SCIENCE], [HIGHLY CITED PAPER & CUP LOGO] and [HOT PAPER & FIRE LOGO] are trademarks of Clarivate Analytics, and/or its affiliated company or companies, and used herein by permission and/or license.