How many dozens of years will the area around the bridge be inhospitable if the concrete is not poured, and mixed correctly? Who would take the risk doing the work except for people that are highly trained or extremely ignorant? There's a lot of specialized work involved with the whole process including creating the reactors, which until recently, have mostly been specialized designs for each plant. Lots of articles about nuclear energy and it's problems can be found online if you're interested in reading more.