ICONE19-43157 Boron Evaluation of Diffusion Phenomenon and Distribution in the Core Using Fluent

Abstract

In the design of pressurized water reactor (PWR), the control rods, the burnable poison rods and the boron acid solution are used to control the core power. Among these facilities, the boron acid solution is indispensable to maintain the critical condition for normal core operation during the compensation of negative reactivity for the fuel consumption and the accumulation of the fission product. The high head safety injection of Maanshan power plant once malfunctioned and therefore the reactor coolant system obtained unnecessary boron. In this study, the validated Computation Fluid Dynamics (CFD) commercial software FLUENT is employed to investigate the boron diffusion phenomenon during the boron acid solution flow into the core, in the high head safety injection malfunction accident. The calculation scope of the model in this paper is cold leg to top of core. The diffusion behaviors within the model can be reasonably captured by the present CFD commercial code. According to the calculation result, the non-uniform boron distribution at the core support forging and the core can be found.