Nuclear isn't the only option for replacing base load production. Natural gas and renewables+pumped hydro are also good options. Though none of them are popular.
(2) Renewable + pumped hydro is much more expensive that just producing electricity directly from nuclear. The environmental impact of dam failures is also bigger than that of an nuclear accident.
For example the Banqiao+Shimantan dam failure killed 110,000, displaced 6,000,000. For comparison Chernobyl killed 9,000 to 93,000 (probably closer to the lower end) and displaced ~130,000.
[1] http://journals.plos.org/plosone/article?id=10.1371/journal....