Solar power just isn't practical. Not only is it not a constant source of power, but it just can't compete with the amount of power a nuke plant can put out.
Look at it this way:
Golmud Solar Park is the largest solar field in the world. It can output a max of 200MW of power and has an annual average of 317GWh.
Three Mile Island is that nuke plant that everyone made a big deal about when one of its reactors failed. It is still operating on the other, undamaged reactor, and can put out four times as much power (800MW) and has an annual average of 6,645GWh.
Despite all this green, environmental nonsense everyone has adopted lately, our power consumption is still going up. Solar power isn't enough to meet the growing demand.