In the study and design of a nuclear power plant, extensive system modeling is necessary to determine how the reactor will perform in any given situation, not only in the normal performance of the reactor, but also in transients including unanticipated transients without scram and hypothetical accidents. One type of nuclear power plant under study is the hybrid energy system, which uses nuclear power to generate both electricity and heat for facilities. Obviously, the second steam cycle in the nuclear power plant requires several design updates and experiments. Unfortunately, the current versions of the Reactor Excursion and Leak Analysis Program (RELAP) do not allow online data streams from experimental facilities to the computational model of the secondary steam loop. Therefore, this study develops a coupling between RELAP5 and Laboratory Virtual Instrument Engineering Workbench (LabVIEW) to model primary and secondary coolant loops. In this way, the LabVIEW model can easily be connected to an experimental apparatus to provide an online data stream and the online transient behavior of an entire nuclear power plant system. This study shows two different coupling approaches and makes qualitative and quantitative comparisons between these approaches.

This paper demonstrates the results of different couplings between the primary and secondary systems of a typical pressurized water reactor (PWR). The primary loop model is a four-loop PWR. The model has been executed with steady state and transients (in this case, a loss-of-coolant accident). The results of both coupling methods have been compared with the typical RELAP5 results.