Effects of Wall Roughness on Flow Stability Analysis of Supercritical Heated Channel

CHAPTER ONE: INTRODUCTION

1.1 Background of the Study

The world‟s population growth is increasing rapidly and requires a corresponding growth in electric energy production. The current worldwide electricity sources, consists of approximately coal 41%, gas 20%, oil 6%, nuclear 15%, and hydro and renewable together 18% [1]. For the world to support its population there must be an increase in the use of energy supplies that are clean, safe and cost-effective. Prominent among these supplies is nuclear energy.

The need to produce energy that is clean, safe and cost-effective led to the formation of a framework for international cooperation known as Generation -IV International Forum (GIF) [1]. This gave rise to future generation of nuclear energy systems, known as Generation IV (Gen IV) which further enabled six nuclear systems to be selected for consideration to assist in meeting the energy needs of the world. The Supercritical Water Reactor (SCWR) [2-4] is one of the six reactors under consideration in the GIF network. The supercritical reactor which is yet to be constructed has been proven from design to be clean, safe and reliable. 

SCWR is a type of light water reactor (LWR) which operates at higher pressure and temperature, with a direct once-through cycle like boiling water reactor (BWR), and the water is always in a single fluid state like the pressurized water reactor (PWR). A common feature shared with the BWR is that as dense fluid enters the reactor core, being subjected to considerable expansion and acceleration along the fuel channels, this phenomenon is the basis for a possible unstable behaviour of that may occur especially in conditions of high power-to-flow ratios.