Calculation of thermal power and low flow rate of main feedwater in 320 MW nuclear power unit

According to the reactor thermal power QinShan 320MW and feedwater flow decreased, starting from the calculation principle of thermal power, analyzes the factors affecting the thermal power calculation, a direct impact on the accuracy of the thermal power of the reactor feedwater flow calculation in thermal equilibrium is analyzed by the heat balance test and water flow diagnostic tests. Then introduces the shortcomings of the conventional method of nuclear power plant feedwater flow measurement and Venturi flowmeter, confirmed the cause of low flow 320MW nuclear power group is the main water supply pipe Venturi throat appear erosion, larger diameter, lead to the differential pressure differential pressure measurement value smaller than the real value, which makes the flow measurement value is less than the true flow. Then, the relative improvement measures of low water supply are put forward. At last, the adverse effects of reactor thermal power reduction on the safety of power operation are discussed on the basis of technical specification requirements. (authors)