Nuclear power is by a country mile the most expensive way the human race has ever discovered to produce electricity. And BTW, pumped storage was originally built in the UK grid in the fifties, to stabilise what what was planned to be an predominantly nuclear powered grid, because back then, nuclear power was pretty much completely inflexible.
From one armchair expert to another, the cost is not really the issue when one looks at the long term. In terms of availability ther is enough fissile thorium to last (the planet) several hundred years. In addition the principal deposits are in 'friendly' countries.