U.P.B. Sci. Bull., Series C, Vol. 68, No. 3, 2006 SATURATED STEAM TURBINE OPERATION MODELING WITH APPLICATION AT NPP CERNAVODA I.PRISECARU, D.DUPLEAC ∗ Lucrarea prezintă rezultatele cercetării în scopul dezvoltării de modele matematice pentru componentele centralei nucleare de la Cernavodă şi anume turbina cu abur saturat. Modulele pentru simularea grupurilor de trepte şi modulul pentru simularea extracţiilor de abur şi sau umiditate la prize sunt module noi, originale. Modelele matematice au fost implementate în codul de calcul MMS cu ajutorul programului CompGen. Sunt descrise rezultatele obţinute pentru un regim tranzitoriu ce constă în reducerea puterii turbinei de abur. The paper presents a part of a work in developing mathematical models for the components of the nuclear power plant with application to the Cernavoda NPP focusing to the steam turbine model development. The whole steam turbine configuration is modeling in modular form. Thus, four interconnected modules are using that describe the turbine stages, the steam extraction, the intermediate moisture separator and steam reheated and the turbine governor valve. The authors propose a new mathematical model for the turbine stages and steam and/or humidity extractions at turbine casings. The mathematical models have been implemented in the MMS code using the CompGen tools. The results obtained for the transient represent a steam turbine power reduction is presented. Keywords: steam turbine, nuclear power plant, mathematical model, MMS Introduction For the steam turbine configuration, more complex or simple mathematical models are mentioned and described in the literature. The mathematical models of the MMS program [1,2] are very general with a smaller degree of precision due to the exclusive usage of theoretical relations for the variation of the internal efficiency and for the calculation of the steam energy loss at the exit from the low- pressure body of the turbine. The mathematical model and simulation module developed respect the modularity principle. The whole turbine is modeled using four modules that are interconnected to simulate the real turbine: the stage group module, the steam extraction module, the intermediary system module (moisture separator and reheater) and the admission valves module. ∗ Prof. , Reader, Dept. of Power Plant, University “Politehnica” of Bucharest, Romania