The US nuclear fleet does do significantly better than the world average, (0.9 CF is about right) but you are grossly underestimating the wind fleet performance and potential. The US wind fleet capacity factor was 0.29 in 2011. (That's the most recent figure I could find quickly.) And if anything, it is the current wind farms that were poorly sited because they were only intended as experimental or demonstration projects. Analyses of wind potential show that the most promising sites, particularly mountain ridges and offshore, have hardly been touched. Scientific studies predict we could expect fleet CFs of 0.4 in the future.