Events related to performance of turbogenerators

This group includes failure of one or two turbogenerators, loss of the main heat sink and turbogenerator load surge. 

Generator load surge is attributed mainly to the reduction in frequency of the grid. The resulting increase in steam consumption by the turbine will cause the pressure to drop in the coolant circuit, with the appearance of steam possible at the MCP inlets, cavitation failure of these pumps and impaired thermal conditions of the fuel channels. 

Special attention should be paid to the pressure dynamics and the possible cavitation failure of the MCPs. 

Loss of in-house electric power supply results in tripping of all pumps (for example MCPs, feedwater pumps and service water pumps) and of both turbogenerators. 

With the transition of coolant flow from forced to natural circulation, a flow-power mismatch is hkely to occur. Turbogenerator trip leads to a pressure increase that should be restricted by operation of MSVs. It will take some time for the emergency pumps to deliver water to the coolant circuit as the diesel generators will first have to be started and loaded. 

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