高強度な高温ガス炉用耐酸化燃料要素の開発; 燃料成形体の機械的強度特性評価

Development of high-strength oxidation-resistant fuel components for high-temperature gas-cooled reactor; Evaluation of mechanical strength properties of fuel compact

東條 拓也*; 山本 健義*; 黒田 雅利*; 相原 純 ; 橘 幸男 

Tojo, Takuya*; Yamamoto, Takenori*; Kuroda, Masatoshi*; Aihara, Jun; Tachibana, Yukio

高温ガス炉の燃料は黒鉛・炭素母材で成形した燃料要素を使用している。しかしながら、高温ガス炉の安全性・信頼性を更に向上させるため、高温ガス炉の特徴的な事故のひとつである空気侵入事故時に、想定をはるかに超える空気が侵入した場合でも、燃料の耐酸化性能が維持されるよう、耐酸化性能を持たせる研究が現在行われている。本研究では、様々なホットプレス条件で作製した耐酸化燃料要素に対して強度試験を行った。その結果、ホットプレス温度では13001600Cの範囲で温度が低いほど圧縮強さは大きくなる傾向を示した。

Fuel compact of high-temperature gas-cooled reactor (HTGR) with inherent safety employs fuel component which was molded from graphite. Development of oxidation-resistant fuel component has been advancing at present, which is fuel component having oxidation resistance formed by SiC. In this study, mechanical properties were obtained on oxidation-resistant fuel components prepared under various molding parameters. Young's modulus was measured by ultrasonic pulse velocity test, and compressive strength was measured by compression test. High correlation was not observed between Young's modulus and hot pressing conditions of temperature and time. There was no correlation between compressive strength and hot pressing time in range of hot pressing temperature of 1573-1873 K and time of 40-120 min, but high negative correlation was observed within range of hot pressing temperatures. Therefore, it was predicted that compressive strength was increased by decreasing hot pressing temperature.