Thermal-hydraulic analysis of the noise effects in super critical water reactor by using the porous media approach in the frequency domain

Abstract

Noise analysis in a supercritical water reactor (SCWR) is considered. This type of reactor is one of the generation IV reactors in which supercritical water is used as a coolant. Since the thermodynamic properties of water at supercritical pressure near the pseudo-critical point is quite sensitive to any perturbation in temperature, one would be interested in having a precise stability analysis in this region.In this research, the effects of coolant temperature fluctuations at the inlet of a fuel assembly were investigated by using the porous media approach (PMA) for a typical SCWR reactor.This analysis is performed using the Fourier transform of the mass, momentum, and energy conservation equations in the frequency domain. The transformed equations were discretized with the finite volume method and numerically solved. Noise calculation was performed for two different frequencies of 0.1 and 1 Hz.The comparison between the achieved results of the applied model and previous studies performed with sub-channel analysis in a typical SCWR (in case of steady-state condition) as well as a VVER-1000 (in case of noise condition) reactors, showed a good agreement.The porous media approach noise calculation code showed that any increment in coolant temperature would result in severe changes in thermal–hydraulics parameters.