If nuclear fusion power reactors were built they would depend on the fusion of Deuterium with Tritium which are two isotopes of hydrogen. However this cannot be done at this time.
If you mean the nuclear fission power reactors now used, the chain reaction that sustains fission depends on neutrons: each fission generates 2 to 3 free neutrons which can potentially cause another fission. Impurities in materials and the positioning of control rods absorb enough of the excess neutrons to keep the reaction at a constant rate (i.e. the reactor is exactly critical at all times it is running at constant power).
Readable spelling helps get the right answer, otherwise we must guess and might answer wrong because of a single letter.
Proton
The answer is PION, short for PI Meson.
Nuclei are held together by the Strong Nuclear Force, which is mediated by the gluon. In particle physics, pion (short for pi meson) is the collective name for three subatomic particles: π0, π+ and π−. Pions are the lightest mesons and play an important role in explaining low-energy properties of the strong nuclear force.
There are two types of subatomic particles located within the nucleus, the proton and the neutron. They way they are arranged, however, is in a kind of jumbled way. That, and the fact that they are constantly interacting via the strong nuclear force by changing back and forth from one to the other means that their really is no single, specific subatomic particle that is located at the center of the nucleus.
The four forces govern the behavior of subatomic particles are the only four forces that we know about in our Universe: the strong nuclear force, the electro-magnetic force, the weak force, and gravity.
it is (c), nuclear energy, in other words changes in the nucleus, which determine the energy and type of particle.
No. The strong nuclear force works through the exchange of a subatomic particle called a meson. Additionally, the strong nuclear force has to hold protons and neutrons together in the nucleus, so having a charge would have no effect on the neutrons.
Nuclear reactions
Neutron particle is needed to begin nuclear chain reaction.
Electrons only.
A positron is a fundamental particle because it does not consist of smaller particles, which would make it a composite particle. Fundamental particles can still decay or change identity however, but they have no (at least at this point) discernible internal structure. A proton on the other hand is a composite particle; it has an internal structure and consists of a mixture of gluons and quarks (which both are fundamental particles).
neutron