ROSA/LSTFを用いたPWR頂部破断LOCA模擬実験における炉心過熱時の3次元蒸気流れと炉心出口温度への影響

Effects of three-dimensional steam flow on exit temperatures during core boil-off in PWR vessel top break LOCA simulation experiments by using ROSA/LSTF

鈴木 光弘; 竹田 武司 ; 浅香 英明; 中村 秀夫  

Suzuki, Mitsuhiro; Takeda, Takeshi; Asaka, Hideaki; Nakamura, Hideo

OECD/NEA ROSAプロジェクト等で実施したPWR事故時のアクシデントマネジメント策の有効性を調べるROSA/LSTF実験において、原子炉頂部破断を模擬した場合の炉心過熱条件下で、制御棒クラスタ案内管に集中流入する高温の蒸気流と、炉心外周部等の非加熱構造材による低温の蒸気流によると考えられる炉心温度分布が検出された。この3次元蒸気流れと、炉心出口での過熱温度検出への影響について報告する。

A core fluid temperature distribution which is considered to be affected by both high-temperature steam flow towards the control rod cluster guide tubes and low-temperature steam flow affected by non-heating structural materials especially in the core peripheral regions was detected during a core boil-off condition in PWR vessel top break LOCA simulation experiments conducted at ROSA/LSTF to study effectiveness of accident management measures in the OECD/NEA ROSA project. Reported are these three-dimensional steam flows in the core and their influences on detection of the super-heated temperatures at the core exit.