Reactors are not becoming more complex, that is a key thing on which the industry, both vendors and utilities, can agree upon with the anti-nukes out there. Complex reactors cause accidents because humans aren't that great at dealing with pressure. So the next generation of reactors, termed Gen IV, are relying on passive safety systems that require little if any human interaction. If something goes wrong, the reactor defaults to a controlled state whether it be a huge loss of coolant accident (LOCA) or otherwise. Before you go saying that legacy reactors are overly complex, massive upgrades and plant optimizations in both control and safety systems have been performed over the last 15 years. Introduction of passive safety systems have significantly lowered PRA's (probabilistic risk assessment) across the board. No one is saying that nuclear power may be a cure all, but it is a prolonged solution that has proven to be quite viable whether people approve or disapprove of it.
Renewable energy would be great it if works. I would love nothing more than to have my house off-grid, if only because of the "coolness" factor. Unfortunately, some renewable forms aren't good everywhere, and people even complain about those. Wind power isn't favored by some because it kills birds or ruins their landscape. Some people don't like the look of solar panels, so many home owners associations have banned their use in their neighborhoods. So unfortunately, while renewables are a hot topic right now, they still have to contend with people's preferences, no matter how petty they are.
I'll say again, it is pretty hard to separate tritium. It's bound in water molecules first of all, so the only way you can really separate it is with gravity-derived methods as there are no chemical differences. The weight difference is fractional, 20g/mol for tritiated water vs 18g/mol for regular. Now, the Canadians use natural uranium reactors with heavy water, D20, well that component of the reactor is very expensive. Separating tritium out of water is ridiculously more expensive as the massive amount of cooling water that is passed through a centrifuge would require quite a large system with a low separation efficiency per CCF of water. Looking at the cross section of hydrogen then deuterium, this double absorption of a neutron isn't going to be a very large product, which is why it is chosen as the moderator in the first place, so very small quantities are produced. The activity is high because of the relatively short half life, not a massive quantity. Now if you do a separations facility for the tritiated water, you would have to either couple it directly to the coolant of the plant or devise a shielded transportation method. Obviously, the coupled method would work the best. Now, you'll also have water at elevated temperatures, probably saturated, so the density will be lower. The loss of thermal efficiency from the separations facility would be huge as you would either have to reheat the feedwater before it enters the reactor, otherwise you'll have a rather nasty reactivity swing, or run the reactor at a much lower power for control reasons. If you see where I'm going with this, you'll see why tritium isn't separated out like this in commercial reactors. The economic cost of producing tritium this way is far more than the benefits would be.
Carbon-14 is low in coal because of its short half-life and atmospheric origin. Uranium and thorium are present in coal, but do not undergo the accelerated fission that occurs in nuclear reactors and so release daughter species at the natural rate rather than concentrating the very hot waste produced by reactors. Owing to the long half-life of uranium, the radioisotopes of iodine or cesium are rarely produced. It would be better to not burn coal, but sulfur, carbon and mercury are much higher reasons to avoid it than trace uranium and thorium.
I'm not sure where you were trying to go with this, but C-14 is a very large release of coal burning, not uranium or thorium. C-14 really won't do too much to anyone in terms of dose, but in terms of total radioactivity, this release is far greater than any other from nuclear.