ナトリウム循環ループを利用した低流量評価技術の適用性に係る予備検討

Preliminary study in a sodium-loop facility for low flow-rate evaluation technology

田中 正暁  ; 今村 弘章; 鈴木 将; 村上 諭*

Tanaka, Masaaki; Imamura, Hiroaki; Suzuki, Masashi; Murakami, Satoshi*

ナトリウム冷却高速炉において、自然循環時に循環流量が著しく低下する場合、電磁流量計による流量計測精度の確保に課題がある。そこで、原子炉の安全性を高める上で主配管に設置される電磁流量計の測定精度を補強する有効な手段を整備しておくことは重要な課題である。本報では、既設ナトリウム循環ループの配管外表面に複数設置した熱電対からの温度データ処理による低流量評価技術の適用性に係る予備検討結果を報告する。

In sodium-cooled fast reactors, electro-magnetic flow-meters (EMFs) installed in the cooling loops may have some degree of measurement uncertainty during the operation of the decay heat removal system by natural circulation because the flow rate in such condition is much decreased from that in the normal operation condition. Then, an evaluation technology in the low flow-rate condition complementary to the EMF has been developed. As the first trial, evaluation technology by analyzing correlations of temperature transient data on the outer surface of the pipe measured by thermo-couples at several locations along flow direction was examined in the existing sodium test loop. Preliminary evaluation results were reported and potentiality of the low flow-rate evaluation technology was confirmed.