Many countries have nuclear reactors: United States, United Kingdom, Russia, China, France, Japan, India, Canada, Romania, Bulgaria, Hungary, etc.

Involving fission & fusion at the same time? These reactions are completely different from each other and have no physical or mathematical relationships. I suppose you could claim that a hydrogen bomb that uses a fission trigger is an example of such an equation, however, the fission occurs before the fusion, so they are still separate and distinct from each other. The mass-energy equivalence equation, E=mc^2, is used to calculate the energy released due to the missing masses found in the fission or fusion calculations, but it comes at the end to convert the mass result into energy only.

Incomplete question

Fission is the splitting of the nucleus of a large heavy atom such as uranium into two smaller parts. Fusion is the sticking together of two light nuclei to make a heavier one, as occurs in the stars. Both processes release energy.

Components in the reactor inside the primary shielding will be radioactive, even after all the fuel has been removed. Provided everything is monitored and assessed properly and health physics advice followed by the operators, there should be no need for anyone to be exposed to dangerous levels during decommissioning.

Nuclear fission involves splitting a heavy nucleus into lighter ones, releasing energy and neutrons. This process is used in nuclear power plants and atomic bombs. Nuclear fusion involves merging light nuclei to form a heavier one, releasing more energy than fission. It is the process that powers the sun and hydrogen bombs. Fusion is more difficult to achieve and sustain on Earth compared to fission, but it has the potential to be a cleaner and more efficient energy source.

Plutonium I think.

Nuclear fission means that in this process the heavy nuclei are split into fragments (or fission products) when bombarded by neutrons and results in release of energy.

The nuclear fission and/or fusion results in loss of mass (or mass defect) that transforms into energy according to formula E = mc2 (c is light velocity). The resulting energy manifests itself as heat energy that produces steam. The steam spins the turbines that spins electric generators and hence producing electricity.

Yes, by introducing a neutron absorber such as boron. In a nuclear reactor this is done by inserting the control rods

In breeder nuclear fission more fuel is produced than what consumed. In conventional nuclear fission less fuel is produced than what is consumed.

Nuclear fission

In actuality, a spontaneous fission event begins a nuclear chain reaction. It kick starts a nuclear chain reaction. And a neutron from that fission will initiate another fission to continue and rev up that nuclear chain reaction.

The process of nuclear fission involves the coming together of smaller atoms to make larger atoms. During this process energy or heat is created by the joining of these atoms.

yes, it is.. when two hydrogen atoms combine to form a helium atom, high amount of energy is liberated both in the form of Heat and light...

They just stay around, being stopped in the fuel rod material. Some are highly radioactive and constitute the high level waste, but if the fuel rods are stored intact, as normally happens with commercial reactors, they just remain in the rods indefinitely.

no one

You must not ask "what element", but "what isotope". Uranium-235 is one example of an ISOTOPE that is appropriate for nuclear fission. Uranium-238 is the same for chemical reactions, but for purposes of nuclear reactions, different isotopes must be considered to be different types of atoms.