Research on improvement of HTGR core power-density, 4; Feasibility study for a reactor core

沖田 将一朗; 水田 直紀; 高松 邦吉; 後藤 実; 吉田 克己*; 西村 洋亮*; 岡本 孝司*

Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 10 Pages, 2023/05

Adoption of SiC-matrix fuel elements in future pin-in-block type HTGR designs will enhance oxidation resistance of the fuel element in the event of the air ingress accident, one of the most worrisome accidents in HTGRs. This would eliminate the need for the graphite sleeves used in the current pin-in-block type HTGR designs and enable high power density core designs with sleeveless and direct coolable fuel structure. Such a concept itself has been suggested by Japan Atomic Energy Agency (JAEA) in the past. However, JAEA has not yet demonstrated the feasibility for a core design with the SiC-matrix fuel elements. The present work is intended to demonstrate the feasibility for a new core design upgraded from an existing conceptual core design, called HTR50S, with 50 MW thermal power and reactor outlet temperature of 750C. The new core design uses SiC-matrix fuel elements and increases the reactor power density to 1.2 times higher than the original HTR50S design. The feasibility is determined by whether the core satisfies the target values in nuclear and thermal-hydraulic designs by performing burn-up calculation with the whole core model and fuel temperature calculations. The calculation results showed that the new core design satisfied these target values on the reactor shutdown margin, the temperature coefficient of reactivity, and the maximum fuel temperature during normal operation.

高温ガス炉の核特性解析手法と核設計に関する研究(学位論文)

後藤 実

JAEA-Review 2014-058, 103 Pages, 2015/03

JAEA-Review-2014-058.pdf:22.36MB

HTTRの試験結果を用いて、以下の検討を行った。(1)核データライブラリの高温ガス炉の核特性解析に対する適用性、(2)改良した高温ガス炉核特性解析手法の適用性、(3)棒状可燃性毒物の高温ガス炉の反応度制御に対する有効性。これらの結果を用いて、2030年代の開発途上国等への導入を目指した熱出力50MWの小型高温ガス炉HTR50Sの核設計を行った。HTR50Sの核設計は、出力密度の向上および燃料濃縮度数の削減を、HTTRの核設計からの主な改良項目として検討を進めた。その結果、HTTRでは12種類あった燃料濃縮度を3種類に削減し、出力密度をHTTRの約1.4倍に向上した炉心を設計することができた。