Design of the first manoeuvrable NPP with heat accumulators

Design of a NPP with feedwater accumulators, ensuring manoeuvrable operation of the power unit with WWER-1000 type reactor and K-1000-60/3000 type turbine including the unit load decrease by 35-40% is described. 4-6 feedwater accumulators each of 7 tousand m3 capacity are included into the power unit. The pressure of supplied water is 3.2 MPa, the temperature is 230 deg C. During load decrease the water from cold condensation tanks is supplied through the system of charging heat exchanger to feedwater accumulators. Condensate is heated by reduced live and wet steam after the high pressure cylinder. As a result the volume of steam which passes through the turbine is reduced and the reactor heat capacity remains stable. When cold condensate tanks are drained, and accumulators are filled, the charging is quenched and power unit is transfered to the basic operation mode. At maximum load water from accumulatos is replaced by reduced live steam and using a special pump it is supplied to steam generator. This mode ensures steam turbine capacity forcing by 166 MW. Simultaneously electric power consumption for the unity needs decreases by 4 MW which results in total gain of capacity equal to 170 MW per one power unit. Technical-and economic comparison with altrnatie variants of NPP participation in the regulation of 24-hourly loading diagrams has shown high economic efficiency of feedwater accumulator application