A Study on the Effect of Geometry and Operating Variables on Density Wave Oscillation in a Supercritical Natural Circulation Loop

Santosh Kumar Rai,Pardeep Kumar,Vinay Panwar,Neha Ahlawat,Raghvendra Upadhyay

doi:10.3390/computation10020025

Abstract

Nowadays, a prime technology in generation IV nuclear reactors, the supercritical water reactor (SCWR), is the main object of focus. The current article aims to develop a thermal hydraulic numerical model for predicting density wave oscillation (DWO) in a supercritical water natural circulation loop (SCWNCL). A one-dimensional thermal hydraulic mathematical model was developed. The numerical model consists of nonlinear mass, momentum, and energy conservation equations, which were discretized by applying the implicit finite difference technique. The numerical model was validated with experimental results, and numerical simulations were carried out to find the marginal stability boundary (MSB) and draw the stability map for the loop. Further, the effects of geometry (i.e., diameter and hot leg length) and operating parameters (i.e., inlet system pressure and friction factor) on the density wave oscillation of the SCWNCL were analyzed.

Highlights

A natural circulation loop (NCL) is a passive safety device used to transfer heat from a heat source to the sink due to fluid flow in the system
The supercritical water natural circulation loop (SCWNCL) stability is demonstrated by the ratio of the mass flow rate of the current time step to that of the preceding time step
The results demonstrate a monotonic enhancement of the marginal stability boundary (MSB) with the increase in the loop diameters

Summary

Introduction

A natural circulation loop (NCL) is a passive safety device used to transfer heat from a heat source to the sink due to fluid flow in the system. In the SCWRs, the size of the turbine is compact due to high steam enthalpy and specific heat capacity, which reduces the capital cost of the load [15]. It will be very helpful for nuclear power plants (NPPs) to combine these advantages. Many researchers have investigated various aspects of SCNCL, and the majority of them have focused on stability assessment

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Conclusion