Thermal influence on steam generator heat transfer tube during sodium-water reaction accident of sodium-cooled fast reactor

ナトリウム冷却高速炉蒸気発生器におけるナトリウム-水反応事故発生時の伝熱管熱的影響

山口 彰*; 高田 孝*; 大島 宏之; 栗原 成計 

Yamaguchi, Akira*; Takata, Takashi*; Ohshima, Hiroyuki; Kurihara, Akikazu

ナトリウム-水反応はナトリウム冷却高速炉の設計基準事故である。蒸気発生器で伝熱管が破損すると、高圧の水蒸気がナトリウム中に噴出、ナトリウム-水反応を引き起こし、隣接する伝熱管に破損が伝播する可能性がある。安全性を確認するためには、隣接伝熱管の温度変化を評価する必要がある。そこで本研究では、伝熱管の温度変化を求める解析手法を開発した。また、本手法をJAEAで実施した実験解析に適用し、その良好な予測精度を確認するとともに、多成分・多相流の特性把握及び伝熱管表面の熱伝達評価を実施した。

A breach of the heat transfer tube (HTT) in a steam generator (SG) of a Sodium Fast Reactor causes sodium-water reaction. The design and safety concern is a possibility of the secondary failure of nearby HTTs that could cause undesirable development of the accident. One needs to evaluate the temperature transients of the HTTs in the reaction region for safety evaluation. In the present study, a computational method is developed for this purpose. It solves the sodium thermal-hydraulics and the heat conduction in the adjacent HTTs. An experiment performed at JAEA is analyzed with the method developed in this study. It is found that analyzed temperatures are in good agreement with the experimental data. Based to the experimental and computational results, multi-phase multi-component flow characteristics are depicted. Furthermore, the heat transfer coefficient is evaluated using the numerical simulation result.