Online estimation approach of the steam specific enthalpy for wet steam turbines in nuclear power plants

Abstract

Wet steam turbines are widely used in pressurized water reactor nuclear power plants. The specific enthalpy of the wet saturated steam is an indispensable variable for the thermodynamic balance and performance monitoring of the wet steam turbines, but it is rarely online measured in practice. In this study, a model-based online estimation approach of the steam specific enthalpy for the wet steam turbine in nuclear power plants is proposed. The wet steam turbine is divided into several stage groups. In each stage group, the steam expansion process, the moisture separation process, and the steam extraction process are captured in mechanism modeling at first. Then, by solving the model, the specific enthalpy and the dryness fraction of the wet saturated steam are obtained. Using the historical operation data of a 1000 MW pressurized water reactor unit, the model-based pseudo-online simulations and the measured data are compared which suggests a high accuracy of the proposed approach.