Modelling and Comparative Analysis for Residual Heat Removal Thermosyphon Heat Transport Devices in Thorium Fuelled PWR

Here, heat transport devices with fluid flow in the closed loop are modelled. A generalized, steady-state analysis for thermosyphon heat transport devices has been devised in this work. Temperature-dependent non-linear thermophysical properties of the working fluid are considered for the analysis. The buoyancy force effect by the working fluid has been taken into account. To increase the height of the thermosyphon loop, physical structures are incorporated. The natural circulation loop may be partly laminar and partly in transition or turbulent flow; thus, a single friction law is not applicable. With varying friction factors, the momentum, mass, and energy equations are solved for thermosyphon heat transport devices, and a methodology has been established to predict the flow rates. Two types of thermosyphon heat transport devices are developed. The THTD I with fluid flow in the shape-of-eight pattern has a higher flow rate than the THTD II. The numerical and experimental data for the flow rates are compared. The flow rate variation against heater power has been analysed. The comparison of predicted steady-state flow rates and experimental data shows agreement with less than 2% variation. To observe the effect of change in diameter on the mass flow rate, parametric analysis has been performed. The flow rate increases exponentially with an increase in diameter. Geometrical parameters, heater power range, and configuration are selected such that unidirectional, non-pulsating, single-phase fluid flow is obtained which is complementary to the work by Ferreri et al. (2007). THTDs are employable in any hazardous hot section to remove the residual heat passively.