GAMMA+ Analysis on High Temperature Helium Heater for Its Optimized Operation Procedure

KAERI is constructing a middle-sized Helium Experimental LooP (HELP) to simulate Very High Temperature gas-cooled Reactor (VHTR) for the main component tests such as intermediate heat exchanger, hot gas duct and others. A high temperature helium heater is one of key components in HELP, because it raises the helium temperature from 500 .deg. C to 950 .deg. C, VHTR outlet temperature. The heater is designed based on the design and operation experiences of the high temperature heater in the small-scale gas loop. Hong et al. discussed the design methodology of a high temperature heater and showed that its design was validated by thermal hydraulic analyses using the system analysis with GAMMA+ and the computational fluid dynamics analysis with CFX. The heater has the following design specification: Power : 300 kW Pressure: 9.0 MPa Inlet/Outlet Temperature: 500/1000 .deg. C Flow Rate: 0.1 kg/s In this study, the high temperature heater was systematically analyzed with GAMMA+ to optimize the operation procedure. The heated material can't stand the thermal shock due to the sudden temperature change. The power-rising step of the heater is found to decrease the temperature rising time without the reduction of the heated element life time. In addition, the operation condition was analyzed for the removal procedure of oxygen and humidity in the helium system