Er, TWh isn't a measure of power. It's a measure of energy. Presumably that 120,000 TWh is consumption per year?

Then we get

120000 TWH/year * (1 / 24 / 365) hours/year ~= 13.7 TW

So you would need 13700 reactors, not 14 million.

Edit: maybe you were just off by a factor of 1000 in your calculation?