Fuel performance under continuous high-temperature operation of the HTTR

HTTRの連続高温運転における燃料性能

植田 祥平   ; 相原 純 ; 坂場 成昭 ; 本田 真樹*; 降旗 昇*; 沢 和弘

Ueta, Shohei; Aihara, Jun; Sakaba, Nariaki; Honda, Masaki*; Furihata, Noboru*; Sawa, Kazuhiro

商用規模では初の国産高温ガス炉燃料であるHTTR燃料は、被覆燃料粒子の製造時破損ならびに原子炉運転中の追加破損を最小限に抑えるよう策定した燃料設計および安全基準をもとに世界最高レベルの製造品質を達成した。また、HTTR運転中における燃料性能を把握するため、燃料から放出された核分裂生成物ガスの測定およびガス放出挙動のモデル化による高精度な評価手法を開発した。950C・50日間の高温連続運転を含むHTTRの運転時において、燃料からの核分裂生成物ガス放出率は1.210を下回る結果が得られ、国産高温ガス炉燃料の優れた照射性能が実証された。これらの日本のHTTR燃料技術によってGEN-IV・VHTR等の実用型高温ガス炉用燃料を世界に先駆けて実用化できる見通しを得た。

Although the HTTR fuel was the first mass-produced HTGR fuel in Japan, it has been fabricated with the highest quality in the world on the basis of design principle and safety criteria to minimize both as-fabricated failure and on-operating-additional failure of the coated fuel particle. A precise technology for evaluating irradiation performance of the HTTR fuel has been developed by measuring fission gases released from fuel and constructing the fission gas release model. Through the HTTR operations including the continuous high temperature operation with 950 C and 50 days, the measured fractional release of fission gas from fuel resulted less than 1.2 10, and a superior irradiation performance of Japanese HTGR fuel has been demonstrated. The HTTR fuel technologies could make a prospect for realization of the practical HTGR as well as the VHTR as a Generation IV nuclear power plant before the rest of the world.