Suppose the Three Mile Island accident was averted (there seem to be plenty of ways to do this, so it shouldn't be particularly hard; for instance, Unit-2 is taken offline as per NRC regulations during routine maintence). What happens?
I would imagine that anti-nuclear protestors would have a generally harder time of it, at least in the US, for the next few years. Nuclear power might remain reasonably popular through the mid-80s, and many of the planned or under construction stations that were canceled or delayed indefinitely IOTL after the accident might end up being built.