First, concerning the uranium 235 that would be used, there is the old problem, that has not been solved in any country, of where the nuclear waste can be permanently stored.
Another concern is what would happen to a nuclear power station should an earthquake occur in the vicinity of the station. Also, if it is built near the sea, a tsunami might affect people’s safety.
When uranium 235 decays it splits up in many ways and more than 200 isotopes of 35 different elements have been identified among the fission products. Strontium 90 is one of the products and this can combine to form strontium carbonate. Now strontium carbonate is unfortunately incorporated into the bones of animals and human beings and so this radioactive strontium remains in the body. It has been reported that fortunately the amount of strontium carbonate taken into the body can be reduced if the person takes liberal amounts of calcium (for example by means of calcium tablets), but strontium 90 is a very dangerous element.
There is also the worry as to what would happen if the uranium was stolen, perhaps by terrorists.
Then there is doubt as to whether the uranium supplies from the earth would last for many decades. A solution to this problem has been suggested in the so-called breeder reactor that converts the more abundant uranium 238 to plutonium 239, but this substance is extremely toxic and highly reactive (one hundred thousandth of one gram of plutonium 239 on entering the body can cause cancer).
With all these problems, is it worth building nuclear reactors?
One alternative is to use industrial hemp as an alternative fuel for power stations. This has been suggested by many. Hemp is a fast growing crop and provides a lot of heat when burnt, is cleaner than coal, and is carbon neutral if more is grown after burning. There are also the cleaner alternatives of wind, solar, wave and other energies.