Eventos Anais de eventos
ENCIT 2016
16th Brazilian Congress of Thermal Sciences and Engineering
TWO-PHASE FLOW INSTABILITIES ANALYSES IN BOILING WATER REACTOR
Submission Author:
Antonella Lombardi Costa , MG
Co-Authors:
WILMER ARUQUIPA COLOMA, Antonella Lombardi Costa, Claubia Pereira, Maria Veloso, Patrícia Reis, Mario Cerrogrande Ramos
Presenter: WILMER ARUQUIPA COLOMA
doi://10.26678/ABCM.ENCIT2016.CIT2016-0140
Abstract
The problem of two-phase flow instabilities is frequent in several engineering systems such as the Boiling Water Reactors (BWR). BWR instabilities occur when an operating condition becomes unstable after some change in system parameters. As a consequence, state variables identifying the reactor working conditions (as the system temperature, pressure and mass flow) are observed to oscillate in different ways depending on the steady state condition of the reactor affecting the power behavior. Out-of-phase oscillations are an important type of instability and its study is relevant for its potential safety implications; in fact, during out-of-phase instabilities, local power oscillates in a self-sustained way so that average reactor power remains nearly constant. In this work, the RELAP5 thermal-hydraulic system code coupled with the PARCS neutron kinetic code have been used to simulate the instability phenomenon. Data from a real BWR nuclear power plant (NPP) have been used as reference conditions and reactor parameters. Typical parameters used to evaluate the instabilities such as the Decay Ratio (DR) and the Natural Frequency (NF) have been analysed and presented in this work.
Keywords
Boiling Water Reactor, PARCS, RELAP5, instability, Power Oscillation
