* The reactants in a fusion reaction are positively charged. This means that they repel each other, making it difficult to bring them close enough together to fuse. In contrast, the reactants in a fission reaction are negatively charged, which means that they attract each other.
* The reactants in a fusion reaction must be moving very quickly. In order to overcome the repulsive forces between them, the reactants in a fusion reaction must be moving at a very high speed. This is because the faster the reactants are moving, the more likely they are to collide with each other and fuse.
* The reactants in a fusion reaction must be at a very high temperature. In order to have enough energy to overcome the repulsive forces between them, the reactants in a fusion reaction must be at a very high temperature. This is because the higher the temperature, the more energy the reactants have.
In contrast, fission reactions are much easier to start. This is because the reactants in a fission reaction are negatively charged, which means that they attract each other. Additionally, the reactants in a fission reaction do not need to be moving very quickly or be at a very high temperature.
Because of these factors, fusion reactions are much more difficult to start and sustain than fission reactions. This is one of the reasons why nuclear power plants use fission reactions instead of fusion reactions.
