Question

Compare the energy input and output for nuclear fission and nuclear fusion.
short paragraph

Answer 1

Fission and fusion both release energy because the products are more tightly bound (higher binding energy per nucleon), but they differ in scale and how much input is needed: a typical thermal-neutron fission (e.g., U‑235) releases ≈200 MeV per nucleus and can be made self‑sustaining with a small initiating neutron, so net energy output is readily harvested in reactors; fusion (e.g., D–T) releases ≈17.6 MeV per reaction but, because it involves much lighter nuclei, yields more energy per unit mass of fuel and cleaner long‑term waste. Fusion, however, requires far greater initial energy to heat and confine plasma (very high temperatures/pressures to overcome the Coulomb barrier), so achieving net positive power is more challenging than for fission.