Cooling system design and structural integrity evaluation

Abstract The high temperature engineering test reactor (HTTR), which is the first high temperature gas-cooled reactor (HTGR) in Japan, is a test reactor with a thermal output of 30 MW, and it can provide heat with temperature of up to 950 °C. The cooling system of the HTTR contains the primary cooling system, the secondary helium cooling system, the pressurized water-cooling system and the residual heat removal system. The structural integrity of the high temperature component such as the heat transfer tubes of the intermediate heat exchanger (IHX) was evaluated by analysis and non-destructive inspections since they are exposed to the coolant temperatures higher than 900 °C during operation. The results showed that there was no problem on the structural integrity. This paper describes design details of the cooling system and the typical structural evaluation results for high temperature components.