Modeling Simulation And Fault Diagnosis Of Condenser In Nuclear Power Plant

The condenser is one of the important nuclear power plants in the secondary circuit of the nuclear power plant.And its key function is to condense the steam exhaust of the steam turbine and,to generate and maintain a proper vacuum at the exhaust port.The operation of the condenser has a direct impact on the efficiency of the steam turbine unit,in extension,the overall safety of the secondary loop system in a nuclear power plant.In this paper,the split-unit flow surface condenser which operates in Hainan Changjiang nuclear power plant is taken as the research object.After the structure and working process of the condenser are simplified,a centralized parameter model based on energy conservation and mass conservation is established according to its working characteristics.Considering the effect of non-condensing gas,cooling tube fouling on the heat transfer process of the condenser and the interference caused by the condensed water flooding the cooling pipe under extreme conditions,when the model is built.Then the simulation model of the condenser is built by SimGen modeling tool,and the model is programmed by Fortran language.The model is embedded in the RINSIM simulation platform and debugged in the SimUgd debugging tool.After the stabilization,the characteristics of the condenser model are studied.Under steady state operation,the error between the main parameters of the condenser and the design value of the system manual is less than 1.5%,which meets the nuclear power plant’s design requirements.The dynamic conditions of the model are simulated,and the operating characteristic curves of different steam exhaust steam loads,different circulating water flows and inlet temperatures are obtained which are consistent with the theoretical trend.In addition,the common faults of the condenser are simulated,including circulating pump trip failure,vacuum pump failure,vacuum failure valve failure,air leakage,seawater leakage,condensate pump failure,clean condensate pump failure,and cooling tube junction.So a reference for maintenance inspection of condensers can be provide by the scale.And compared with the debugging report of the special working condition of the condenser half-side disengagement of the circulating pump of Hainan Changjiang nuclear plant and the 50%exhaust steam load,the change trend is basically the same.Afterwards,the back pressure optimization is carried out,and the appropriate circulating water pump operation mode is selected for different circulating water inlet temperatures,which can obtain the maximum net power point to determine the optimal back pressure.Finally,combined with the operating experience of the unit,the common faults and fault symptom sets of the condenser are summarized,and the fault vector diagnosis is carried out by the support vector machine method of the radial basis kernel function.The established training model has high precision and can accurately determine the type of instance fault.