Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : September 03, 2017 - September 06, 2017
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 subassembly can mix with the cold sodium from the control rod (CR) channel and the blanket assemblies at the bottom of Upper Internal Structure (UIS). Temperature fluctuation due to mixing of the fluids at different temperature between the core outlet and the bottom of the UIS may cause high cycle thermal fatigue on the structure around the bottom of the UIS. A water experiment using a 1/3 scale 60°-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. By the velocity measurement using the particle image velocimetry (PIV), it was known that the swirling flow in vertical direction from the upper to the lower regions of the CIP was formed around the flow-hole of the back-up control rod (BCR) channel. The large intensity of the temperature fluctuations was observed near the cold fluid outlets simulating the BCR channel. The countermeasure to mitigate the temperature fluctuation intensity was applied and its effectiveness was confirmed.
