Reactor, turbine and feedwater regenerative system - assembly behavior

The paper presents the results of heat balance calculation for the secondary circuit of NPP Cernavoda Unit 1. We made several calculations for abnormal regimes caused by failure of one of the regenerative reheaters. Previous calculations reported by General Electric took into account a reduction of the reactor power level of 90% of rated power. The loss of power due to abnormal operation was of about 12-14%. In our calculation we considered that reactor power was kept at a constant level - the rated power level - in order to minimize the loss of power due to operating the reactor in an abnormal regime. From our calculation a loss of power of maximum 4% of rated power resulted, much less then the prior case in witch reactor power was reduced to 90%. We concluded that operating the reactor at 100% of its rated power in abnormal condition of loss of one of regenerative reheaters appears to be both safer and more economical (saving about 50000 Euro/day) and we recommend changing the operating procedures for this abnormal regime. (authors)