The Effect of Dissolved Gas Bubble Nucleation on Natural Convection Heat Transfer in Narrow Channels

Research reactors present a different set of operating conditions than do light water (power) reactors (LWRs). Thermal-hydraulic transient/safety codes, such as the Reactor Loss of Coolant Analysis Program (RELAP), have been verified against experimental data from several test facilities designed for the operating conditions of LWRs. However, the operating pressures, temperatures, fuel type, and flow direction are quite different in most high-power research reactors. Furthermore, the coolant (water) in these reactors generally is not degasified and hence contains dissolved air. Results are given of benchmark experiments compared with RELAP predictions for the conditions encountered during a loss-of-coolant accident for a typical research reactor.