Radioisotopes for many uses (e.g. medical, industrial, scientific) are produced in nuclear reactors.
In some reactors it is, depends on the design.
The most common coolant used in nuclear reactors is water. There are light water reactors (using "regular" water), and the heavy water kind of reactor.
It is Uranium
Plutonium is used as nuclear fuel for nuclear reactors. Plutonium isotopes (239, 241) are fissionable with thermal neutrons releasing an extremely great quantity of energy.
Uranium
There is a small reactor at Sydney used to produce radioisotopes. No power reactors.
Well, as nuclear reactors are nuclear reactors, nuclear reactors are not used inside nuclear reactors.
It is mostly used to generate electricity, that is all large power reactors can do. There are some small reactors designed to enable samples to be irradiated and removed quickly, to provide radioisotopes for medical and industrial use.
Current nuclear reactors rely on nuclear fission as their nuclear reaction.
We use nuclear fission in nuclear reactors to tap nuclear energy.
No, at least not for power reactors
There may be Radium, Thorium, Uranium or even Plutonium which can be used in nuclear reactors.
No substitute for nuclear power reactors especially if there is no available fossil fuel.
Nuclear reactors and nuclear weapons
No, nuclear fission operates all nuclear reactors. If they are power plant reactors it is used to generate electricity.
Lots of different things, especially in certain types of laboratories.But considering the categories you have the question in I guess the answer might be: radioisotopes of elements.
Mainly generation of electricity. However production of isotopes used to examine structures such as welds, to calibrate instruments, or to incorporate into devices such as smoke alarms, is also important. These radioisotopes are produced in small reactors built for the purpose. They also produce medical radioisotopes.