Carnot Engine Physics Question?

Suppose that a nuclear power plant operates in a Carnot cycle. Estimate the temperature change, in Celsius, of a river due to the exhausted heat from the plant. ume that the input power to the boiler in the plant is 27 x 10^8 W, the efficiency of the use of this power is 27%, and the river flow rate is 10.0 x 10^6 kg/min.