In addition, one negative of nuclear I don't see come up on HN very often, is that nuclear power plants pose an extra risk in regards to nuclear proliferation and terrorism concerns. I do think that some of the recent decline of nuclear is, in part, geopolitical. You don't see groups of nations banding together to stop another nation from building a coal plant.
For example, http://large.stanford.edu/courses/2012/ph241/chowdhury2/
[1] https://en.wikipedia.org/wiki/Nuclear_power_proposed_as_rene...
Russia, S. Korea, India, & China are building economically feasible reactors right now because they standardized on a design and are building multiple of the same kind. [1,2]
Current batteries are not a feasible solution for leveling large capacity renewables. The 10-day total wind outage that just happened in the US pacific northwest kept 4 GWe of wind offline. The battery to back that would have been 100 stories high on a football field and cost $90B, and would have to be replaced every 20 years or less. Not even 100% renewable superstar Jacobsen [3] (who's suing his scientific critics) suggests using batteries for large-scale load balancing. (He uses hydro with pumped storage, which is actually not a good option due to biogenic methane emissions) [4]
Nuclear waste is a solved problem, technically. You put it in crystalline bedrock, salt deposits, or deep boreholes. The Finns are opening their repository in 2023 [5]. It's a political problem.
There's also very little of it; you're entire lifetime of waste (were you 100% nuclear) fits in a soda can. Nuclear is one of the only energy sources where it's even feasible to consider handling the total waste because of this energy density.
[1] http://www.world-nuclear-news.org/C-Russia-achieves-serial-n...
[2] https://www.sciencedirect.com/science/article/pii/S030142151...
[3] http://www.pnas.org/content/112/49/15060
[4] http://journals.plos.org/plosone/article?id=10.1371/journal....
[5] https://en.wikipedia.org/wiki/Onkalo_spent_nuclear_fuel_repo...
Look, HN loves nuclear. You’ll find people here who propose running an actual nuclear reactor in every backyard. You’ll find excuses why the Sowjets were obviously incapable of securely running a nuclear plant, but capitalist societies can do it without a hitch. Then, two years later, you’ll have people telling you the Japanese were obviously incapable of running a nuclear plant, but France is obviously different. Plus, the Green conspiracy has somehow thwarted the breakthrough of cold fusion pebble bed thorium reactors, but now it’s just around the corner.
Meanwhile, in reality, it has simply become economically unfeasable to build nuclear reactors. Solar and wind are doing their version of Moore’s law. Batteries, and other storage technologies, are taking a bite out of the storage problem. Smart grids, combining load variability and harnessing end-user storage capacity for grid storage are basically there.
Your suggestion of throwing nuclear waste into the most corrosive substance available in quantity (sea water) nicely demonstrates this naïveté. There’s a post on the front page right now that shows that low-grade radioactive exposure has literally killed hundreds of thousands. Just because you can’t see it, and it was once the darling of science fiction, does not mean it won’t kill you.