What is the meaning of Fusion ?

Fusion is the same process that powers the sun and is already being conducted in laboratories all over the world. Scientists have made exponential progress in fusion energy over the past few decades but progress was slowed by budget cuts in the 1990’s.

Bethe chose this sequence of reactions because it requires less energy than does the direct fusion of four protons and, thus, is more likely to take place in a star. Bethe was able to show that the total amount of energy released by this sequence of reactions was comparable to that which is actually observed in stars.

Fusion produces energy by fusing together two hydrogen isotopes, deuterium and tritium, that are virtually inexhaustible. Deuterium comes from ocean water and tritium, though limited today, will be produced from lithium as a byproduct of the reaction. Fusion therefore holds the promise of complete energy security.

The Bethe carbon-cycle is by no means the only nuclear fusion reaction. A more direct approach, for example, would be one in which two protons fuse to form a deuteron. That deuteron could then fuse with a third proton to form a helium-3 nucleus. Finally, the helium-3 nucleus could fuse with a fourth proton to form a helium-4 nucleus.

The only byproducts of the fusion process are helium and a fast neutron, which carries the heat to make steam, meaning there is none of the long-lived radioactive waste produced by conventional nuclear fission reactors.

The net result of this sequence of reactions would be the combining of four protons (hydrogen nuclei) to form a single helium-4 nucleus. The only net difference between this reaction and Bethe's carbon cycle is the amount of energy involved in the overall set of reactions.

Other fusion reactions include D-D and D-T reactions. The former stands for deuterium-deuterium and involves the combination of two deuterium nuclei to form a helium-3 nucleus and a free neutron.

Fusion does not rely upon a chain reaction so there is no chance of a runaway reaction that could lead to a meltdown. In the event of an equipment failure, the small amount of fuel available stops reacting instantly and the plant cools automatically.

The second reaction stands for deuterium-tritium and involves the combination of a deuterium nucleus and a tritium nucleus to produce a helium-4 nucleus and a free neutron.

The positive spillover effects of the U.S. fusion program are already being felt. Fusion scientists are making advancements in superconductors, super-power lasers, new high-efficiency semiconductor light sources, large and small-scale robotics, and supercomputing and modeling.

The term "less energy" used to describe Bethe's choice of nuclear reactions is relative; however, since huge amounts of energy must be provided in order to bring about any kind of fusion reaction. In fact, the reason that fusion reactions can occur in stars is that the temperatures in their interiors are great enough to provide the energy needed to bring about fusion

The fusion industry already supports thousands of jobs and businesses across the country. 47 out of 50 states support the fusion industry.

Because those temperatures generally amount to a few million degrees, fusion reactions are also known as thermonuclear (thermo = heat) reactions. The heat to drive a thermonuclear reaction is created during the conversion of mass to energy during other thermonuclear reaction.

Despite pioneering fusion energy research, a lack of commitment risks ceding leadership to other countries. Although the National Ignition Facility currently leads the world in inertial fusion research, the magnetic fusion facilities in other countries have surpassed the technological capabilities of the best American labs.

Fusion bombs. From a military standpoint, the fusion bomb had one powerful advantage over the fission bomb. For technical reasons, there is a limit to the size one can make a fission bomb. However, there is no technical limit on the size of a fusion bomb. One simply makes the casing surrounding the fission bomb larger.

Without the need for fossil fuels, the U.S. can conduct foreign policy according to its values and interests, not according to commodity prices.

On August 20, 1953, the Soviet Union announced the detonation of the world's first fusion bomb. It was about 1,000 times more powerful than was the fission bomb that was dropped on Hiroshima less than a decade earlier. Since that date, both the Soviet Union (now Russia) and the United States have stockpiled thousands of fusion bombs and fusion missile warheads.

The establishment of a high-tech industry will bring vast new streams of revenue to America’s leading industrial companies, creating thousands of new jobs. Creating a new industry will give America a “first mover advantage” that will increase our global competitiveness with economic implications for generations.

Possible peaceful uses for fusion. As research on fusion weapons continued, attempts were also being made to develop peaceful uses for nuclear fusion. The containment vessel problems remain daunting because at the temperatures at which fusion occurs, known materials vaporize instantly.

Absent steps to accelerate fusion development, current projections estimate that commercial-scale fusion power plants could be built in the 2040’s. Yet a timeframe that always remains decades away lacks ambition and forecloses on domestic leadership. The American fusion community believes that given adequate resources, developing commercial fusion power can be achieved on an accelerated timeframe.

One way to control hot plasma is with a magnetic field. One can design such a field so that a swirling hot mass of plasma within it can be held in a specified shape. Other proposed methods of control include the use of suspended microballoons that are then bombarded by the laser, electron, or atomic beam to cause implosion. During implosion, enough energy is produced to initiate fusion.

The production of useful nuclear fusion energy depends on three factors: temperature, containment time, and energy release. That is, it is first necessary to raise the temperature of the fuel (the hydrogen isotopes) to a temperature of about 100 million degrees.

Then, it is necessary to keep the fuel suspended at that temperature long enough for fusion to begin. Finally, some method must be found for tapping off the energy produced by fusion.

In late twentieth century, scientists began to explore approaches to fusion power that departed from magnetic and inertial confinement concepts. One such approach was called the PBFA process. In this machine, electric charge is allowed to accumulate in capacitors and then discharged in 40-nanosecond micropulses.

Lithium ions are accelerated by means of these pulses and forced to collide with deuterium and tritium targets. Fusion among the lithium and hydrogen nuclei takes place, and energy is released. However, the PBFA approach to nuclear fusion has been no more successful than has that of more traditional methods.