先進的なナトリウム冷却高速炉の炉心出口部における サーマルストライピング現象に関する水流動試験 (1)制御棒周辺部の温度変動緩和対策の提案
Water Experiments on Thermal Striping Phenomena at the Core Outlet of an Advanced Sodium-cooled Fast Reactor? (1) Proposal of Countermeasures to Mitigate Temperature Fluctuations around Control Rods?
小林 順 Jun KOBAYASHI 相澤 康介 Kosuke AIZAWA 江連 俊樹 Toshiki EZURE 栗原 成計 Akikazu KURIHARA 田中 正暁 Masaaki TANAKA
High Cycle Thermal Fatigue Particle Image Velocimetry Sodium-cooled Fast Reactor Thermal Striping Upper Internal Structure
A design study of an advanced sodium-cooled fast reactor (Advanced-SFR) has been conducted in Japan Atomic Energy Agency (JAEA). Hot sodium from the fuel assembly can mix with cold sodium from the control rod (CR) channel and the blanket assemblies at the bottom plate of the Upper Internal Structure (UIS). Temperature fluctuation due to mixing of the fluids at different temperature between the core outlet and cold channel may cause high cycle thermal fatigue on the structure around the bottom of UIS. A water experiment using a 1/3 scale 60 degree sector model simulating the upper plenum of the Advanced-SFR has been conducted to examine countermeasures for the significant temperature fluctuation generated around the bottom of UIS. In this paper, we focused on the temperature fluctuations near the primary and backup control rod channels, and studied the countermeasure structure to mitigate the temperature fluctuation through temperature distribution and flow velocity distribution measurements. As a result, effectiveness of the countermeasure to mitigate the temperature fluctuation intensity was confirmed. And we obtained knowledge to avoid high cycle thermal fatigue that can be applied in the design of the reactor.?