Numerical Investigations of Ball Valve Performance in Variable Valve Diameters, Openings and Flow Regimes

Abstract

A United States Nuclear Regulatory Commission’s (USNRC) study found that 65% of Nuclear Power Plant (NPP) system failures are due to human errors [1]. The Strategic Management Analysis Requirements and Technology (SMART) valve initiative by the Department of Energy (DOE) is a part of the Light Water Reactor Sustainability (LWRS) program to improve the energy economics of the existing light water reactors (LWR) [2]. SMART valves can improve plant safety by reducing human intervention, balancing thermal dispatch, and reducing operation costs. An NPP has complex hydraulic networks containing various valves. Regarded as the backbone of an NPP, hydraulic networks are responsible for core-cooling, heat transfer, thermal extraction, and dispatch while maintaining their safety. This study presents three different-sized full-port ball valves’ performance in both water and steam flow conditions. Using Star-CCM+, different flow regimes at various valve positions are analyzed, and performance parameters are compared to strategize the automated SMART valve network control. It is observed from the performance parameters that the ball valves are suitable to control the flow from 45° to 90° with loss coefficient values below 100 and follow a distinct pattern across all the sizes. The rate of change for flow coefficients per degree gives us an overview of the precision of control needed for flow regulation, predominantly in wider openings, where a slight actuation of the valve causes significant changes in flow parameters.