核反應問題(唔該幫手)

This is a physics question not chemistry.

1. Of course, U-235 after getting a slow neutron will turn into U-236. But the collision makes the newly formed U-236 nucleus unstable and it spontaneously fissioned into 2 simplier nuclei.

2. 衰變 is decay. It is not necessary to be true for example when Xenon-135 (which is originally radioactive) absorbs a neutron, the newly formed nucleus Xe-136 is stable and is non-radioactive.

3. Nuclear fusion requires high temp, (energy) for the nuclei to move faster to overcome the electrostatic force between nuclei and to have collision. So high temp is important to nuclear fusion.

4. Every particle above absolute zero in fact contains energy. So, in this case, a slow neutron contains enough energy for the U-235 reaction, but may be insufficient for other nuclear reactions.

5. Nuclear fission is in fact breaking down a large nucleus into smaller ones. Releasing a nucleus is another matter.