Fission and Fusion / Nuclear power

3) Fission and Fusion
Nuclear energy is 10 million times more concentrated than chemical energy. One consequence is the awesome destructive power of nuclear weapons.
Nuclear energy plays a major role in the natural universe, powering the Sun and other stars. On Earth, applications of nuclear energy became a serious possibility in the 1930s, a reality in the 1940s, and a fact of life in the 1950s. Since then, the use of nuclear energy for both peaceful and military purposes has increased substantially. Proliferation of nuclear weapons throughout the world presents a serious threat to human survival. On a more positive note, nuclear fission supplies more than 15% of the world's electrical energy, and nuclear fusion raises the prospect of a cleaner, safer nuclear power source with nearly limitless fuel resources. The curve of binding energy leads to the possibility of nuclear energy release through fusion-the joining of lighter nuclei to form heavier ones nearer the peak of the binding energy curve. Fusion in the Sun provides the energy that sustains life on Earth. Fusion energy released in our thermonuclear weapons, on the other hand, has the potential to destroy that life. For nuclei heavier than iron, energy release can occur if a nucleus splits, or fission, into two lighter nuclei. In contrast to fusion, nuclear fission seems to be of little consequence in the cosmic scheme of things. A self-sustaining fission reaction did occur naturally in what is now a uranium mine in Africa some three billion years ago, and it has provided useful information on the long-term movement of nuclear waste through the environment. Technologically, though, nuclear fission is important: it is the one major energy-releasing nuclear reaction that we can now sustain in a controlled manner to produce electricity, while uncontrolled fission reactions play an important role in nuclear weapons.
The curve of binding energy , shows regimes where fusion and fission can result in the release of nuclear energy .

Fission and Fusion :

a) Nuclear Fission

b) Nuclear Fusion