Power is energy per unit time, so a Watt power output means you are producing a Joule of energy every second. A MW is a million Joules per second. One Joule is the energy released when a 100 gram mass is dropped a distance of 1 meter--not all that much, really.

Although you never actually say it, I presume what you meant to say was those 30 tons per plant are produced over a year of operation.

What you don't understand is that the fuel elements that are placed into a plant are not consumed during the generation of electricity. So little uranium actually undergoes fission that the elements weigh pretty much the same when they come out as waste as when they went in as fuel. Nuclear plant don't create waste mass, they convert fuel assemblies into waste.

Only a fraction of each fuel element is Uranium, and only a few percent of the Uranium is fissionable U235, and most of that is never consumed before the fuel element is removed as waste. Even the Uranium that does fission survives as fission products, other elements formed from the fragments of the split Uranium nucleus.

So, 30 tons of waste is not 30 tons of potential fuel. Most of that weight is in fission products, or in the cladding and structure of the fuel elements, or in the inert U238 that makes up about 95% of the fuel. These materials are highly radioactive, contaminated, (which is why they are dangerous waste) but they have very little energy in them. The energy is trapped in the small amount of unconsumed U235 fuel still in the fuel elements, and the Plutonium that is formed by neutron absorption in the non-fissile, inert Uranium 238. This adds up to at most a few tons--not thirty. The unconsumed fuel must then be extracted and put back into another reactor before that energy can be released. The Plutonium is not allowed in reactors by law, because it is potential weapons material. Its energy is accessible only if it is incorporated into a bomb. The reason most of the fuel (U235) in a fuel element is not consumed is because fission products absorb stray neutrons and inhibit the chain reaction so the element must be replaced long before all the fissionable material is consumed.

However, its a moot point since both the newly produced plutonium and the unconsumed U235 are still trapped in the "waste", and we do not process the waste and extract it. It is all just warehoused at the plants where it is generated. The stuff generates heat, but only a tiny amount compared to the uranium that fissioned.

You seem to think that because this material is radioactive, all the energy locked up in it is being constantly released into the environment through radioactive decay. That is simply not true. The plants generate their energy from fission, not radiation. Radioactive waste is not fissionable. That's why it is waste. It is not going to heat up the planet. The reactors produce a lot of heat, but it is no different from the heat produced by fossil fuels, and it is not heat from power generation that causes global warming, it is greenhouse CO2 generated by burning fossil fuels to generate heat. The warm in global warming comes from sunlight, not our industry. The amount of energy the earth absorbs from the sun, and then radiates back into space every day, far exceeds what we manufacture. Because of greenhouse gases, the earth's ability to radiate excess heat into space is impaired, it has NOTHING to do with the heat we generate here. This is why nuclear power has the potential to combat global warming, if its other problems can be worked out..

Think about it. All that uranium that you think is heating up the planet would be heating up the planet if it were still in the ground as an unprocessed ore. Its only spread out over a much larger area. I'm sorry, Johannes, I don't mean to embarass you, but though you employ a lot of unnecessary algebra, you don't understand the basic physics of what is going on, so you are only embarassing yourself.