Fusion Essay

CHAPTER 2:

TOKAMAK

1.1 What is Fusion?

Fusion is the process at the core of our Sun. What we see as light and feel as warmth is the result of a fusion reaction: hydrogen nuclei collide, fuse into heavier helium atoms and release tremendous amounts of energy in the process.

The gravitational forces at play in the Universe have created the perfect conditions for fusion. Over billions of years, these forces caused the hydrogen clouds of the early Universe to gather into massive stellar bodies. In the extreme density and temperature of their cores, fusion occurs. Fig. 1 Fusion is the energy source of the Universe, occuring in the core of the Sun and stars.

1.2 How does fusion produce energy?

Atoms never rest: the hotter they

In a star as in a fusion device, plasmas provide the environment in which light elements can fuse and yield energy. Fig. 3 European JET Tokamak

In ITER, the fusion reaction will be achieved in a tokamak device that uses magnetic fields to contain and control the hot plasma. The fusion between deuterium and tritium (D-T) will produce one helium nucleus, one neutron, and energy.

The helium nucleus carries an electric charge which will respond to the magnetic fields of the tokamak and remain confined within the plasma. However, some 80 percent of the energy produced is carried away from the plasma by the neutron which has no electrical charge and is therefore unaffected by magnetic fields. The neutrons will be absorbed by the surrounding walls of the tokamak, transferring their energy to the walls as heat. Fig. 4 ITER Tokamak

In ITER, this heat will be dispersed through cooling towers. In the subsequent fusion plant prototype DEMO and in future industrial fusion installations, the heat will be used to produce steam and—by way of turbines and alternators—electricity. [1]

1.4 WHAT IS A