Modeling primary and secondary coolant of a nuclear power plant system with a unique framework (MCUF)

Abstract

Within the study and design of a nuclear power plant extensive system modeling is necessary to determine how the reactor is going to perform in any given situation, not only in the normal performance of the reactor but also transients including anticipated transients without scram (ATWS) and hypothetical accidents. Primary and other loops in multiple coolant loop systems in nuclear power plants can be modeled in nuclear system codes, such as Reactor Excursion and Leak Analysis Program (RELAP5), COBRA-TRAC, TRACE, and ATHLET, for the interaction and feedback effects between the coolant loops. In the recent years, new components, such as turbine, coolant pump, advanced compact heat exchangers, valves, sensors, instrumentation and control systems, are being designed to use in the coolant systems. However, current system codes are not capable of integrating the computational model of the whole nuclear power plant system to an experimental apparatus. Therefore, this article proposes a new coupling between a system code and Laboratory Virtual Instrument Engineering Workbench (LABVIEW) in a unique framework (called as Modeling of Coolant Systems with a Unique Framework -MCUF-) that allows integrating an experimental apparatus or a facility to a whole power plant model. MCUF allows online or interactive data exchange by using the powerful and flexible tools of LABVIEW. This article demonstrates how coupling between the primary and secondary coolant system of a typical Pressurized Water Reactor (PWR) can be performed by using MCUF. The primary and secondary sides of the PWR are modeled with RELAP5 and LabVIEW computer simulators respectively. The coupling between RELAP5 and LabVIEW has been executed with steady state and transients, in this case a loss of coolant accident (LOCA) for a four loop PWR. The results of the coupling have been compared with the typical RELAP5 results which significantly depend on “hard coded” data for second coolant loop. Code-to-code benchmark results demonstrate that this unique coupling framework has a good agreement with the RELAP5 code results with “hard coded” data for the secondary coolant system.