Experimental study on the passive residual heat removal system of swimming pool-type low-temperature heating reactor

The Passive Residual Heat Removal System (PRHRS) of Swimming Pool-type Low Temperature Heating Reactor (SPLTHR) runs at low temperature and pressure condition, which is completely different from the PRHRS of other reactors. According to the previous calculation results, an experimental facility with a power of 240 kW was built. Experimental data shows that after PRHRS is running, the temperature of the reactor pool water drops rapidly. The power of PRHR heat exchanger (HX) will gradually stabilize at about 1500 s, and both the pool water temperature and the air temperature have a significant effect on the power. The experimental Nusselt number (Nu) are all bigger than the calculated values of correlations, indicating that these correlations are not applicable to the natural convection outside the PRHR HX tube bundle. After analyzing the 30 groups of natural convection data outside the PRHR HX vertical tube bundle, the fitting correlation is in good agreement with the experimental data, which can provide important reference for engineering applications.