Solar panels need to be cleaned and at the end of their lifespan, several years if not decades, need to be replaced. I dont know about nuclear rods, but they do require security and safety measures.
http://googleblog.blogspot.com/2009/07/should-you-spring-cle... indicates that solar panels mounted flat do indeed need to be cleaned, but panels mounted at a sufficient angle will be rinsed off adequately by the rain and do not seem to benefit measurably from manual cleaning.
Average soiling loss for tilted installations is around 5%, but it can vary quite a bit with location and rainfall patterns, so it is occasionally worth manually cleaning them.
Plus they must be first made of silicon and rare metals and then deconstructed, both in a very toxic and energy consuming processes. Nuclear waste on the other hand is not only coming form nuclear plants but also from medicine, industry (mostly food disinfection) and science -- shutting down all nuclear plants won't make this issue disappear.
