Question

We have plenty of nuclear reactors around the world. They are consuming nuclear resources of the Earth. Nuclear elements are scarcer than the other elements, aren't they? When are we going to run out of them? How many years do we have left?

Answer 1

According to this site, we have about 433 working reactors, 65 under construction, 160 planned and 323 proposed which is too many... We're consuming about 67,990 tons per year of U-238 which would probably die out soon within about 75 years.

Besides fission products, spent fuel rods contain some plutonium produced by the U-238 in breeder reactors by absorbing neutrons. This plutonium and leftover uranium can be separated in a reprocessing plant (Reprocessing involves the removal of any leftover uranium and the plutonium that has been formed) and could be used as reactor fuel again.

In fact, Not only U-235 is used as a Nuclear Fuel. For now, it's the one which is mostly used. But, there are other fuels like Pu-239 from Breeders which we would use after constructing enough Breeder reactors and U-233 obtained from Th-232 whose fissile properties are somewhat similar to U-235 but it emits higher levels of radiation compared to Pu-239. It's used as fuel in the KAlpakkam MINI Reactor (KAMINI) which is near my area, at Chennai.

After the fuel has been in the reactor for about 18 months, much of the uranium has already undergone fission (We know about Half-life, don't we?) and a considerable quantity of fission products would've been built up in the fuel. The reactor is then refueled by replacing about 1/3 of the fuel rods. This generally takes one or two months. The fission products are then put in a form for long term storage. A large reactor produces about 1.5 tons of fission products per year. The fission products are originally in a mixture with other substances, so reprocessing is required to get it down to a 1.5 tons.

If the waste is incorporated into a glass, the total weight is 15 ton. If the density is 3 times that of water, which means the volume of the waste is 0.5 cubic meters, and the volume of the waste glass is about 5 cubic meters.

But one thing, WE humans (especially the Government) won't leave it like that as these facts have already scared us before few years. As Breeder reactors have more neutron economy than normal power reactors, we would increase the proposals for them and even we would jump toward Integral Fast reactors for now. Due to these increasing technologies, we would somehow fuse some creepy things to produce Uranium in the near future. For now, we won't consider it, 'cause it's available to us as common as tin or zinc..!