Physics question Thermal properties of matter?

A typical nuclear reactor generates 1000 MW (1000MJ/s) of electrical energy. In doing so, it produces 2000 MW of "waste heat" that must be removed from reactor. Many reactors where the intake water is at 18 degrees C. Stae regulations limit the temperature of the output wat to 30 degrees C so as not to harm aquatic organisms. How many kilograms of cooling water have to be pumped through the reactor each minute?