variavel0=<b>Lamartine N. F. Guimarães</b> - guimarae@ieav.cta.br Centro Técnico Aeroespacial
<b>Glauco Antonio Santos da Silva</b> - glaucoass@ig.com.br Consultor independente
<b>Eduardo Madeira Borges</b> - eduardo@ieav.cta.br Centro Técnico Aeroespacial
<b>Abstract.</b> In this work a Once Through Steam Generator (OTSG) numerical model is presented. This model was developed and programmed in the MATLAB simulation environment. Steam generators in general are very important components of the steam cycle of every thermal power plant, in especial nuclear power plant. The particular model presented here is to be used in a fast metal cooled reactor. And it is, as the name gives it up, the straight tube and counter current type. This model is part of a larger set of models named "SIStema MODular Integrado de Simulação - SIMODIS," which together are designed to represent a good portion of a power plant. The OTSG model presented here is part of the REARA-60 concept developed at IEAv/CTA. Together with the model development a friendly graphical interface has also been developed. This graphical interface is to be executed in the MATLAB simulation environment, it is WINDOWS compatible and it was built using the VISUAL C++. The graphical interface allows the user to visualize the behavior of the OTSG in the steady state as well as in the transient. It also allows the user to choose between some pre defined transients or change important input parameters directly. Several tests were performed and the results obtained match quite well previous results published in the literature. It must be said that the graphical interface facilitates quite a lot the programs use, allowing even it to be used in classes were a demonstration of the working of this equipment may be considered of importance.
<b>Keywords.</b> Straight tube steam generator, Computational Modeling, Simulators.