Nuclear Fission or Fusion, Clearing Up the Confusion

Before I TELL you what significance this day has in history... the teacher in me is asking you to bring yourself back to 1986. (Of course the title of this entry is a huge hint!)

That's easy for me to do, and I remember the year well, as it's the year I was married. Of course, silly girl that I was, my world revolved around my husband-to-be, and at this point in the year we were not engaged "just" dating.

But this event transcended the dreamy nature of a girl whose heart and mind were focused elsewhere.

Have you figured out yet what it was that happened on this day?

It happened on another continent. It was shrouded in secrecy for quite some time, although its effects may have been global in nature.

Ok... so on this day in 1986 the Chernobyl Nuclear Reactor disaster occurred. This was the feared actual nuclear meltdown. The fallout was much greater than Hiroshima, estimates put it at around 40% more! Quite something to imagine! (I've been to Hiroshima and seen the damage.)

The disaster was something that could and should have been prevented. It was a result of man's arrogance over proven theories and procedures. Officially it was ruled as human error and faulty design.

This incident along with our country's own Three-Mile Island disaster did much to create fear about nuclear energy, which I believe may be a viable source to replace our dependence on oil. In light of that, I'd like to share a report our daughter did in 2005 that was the winner at our local science fair judged by local scientists.

I hope that it will give you reason to consider nuclear energy as a source for our country's energy.

It's called, Fission or Fusion, Clearing Up the Confusion


Introduction
Nuclear science has been around since 1913, although research leading up to the discovery of the atom and the structure of it had been occurring since the 1890s. Nuclear energy has powered electricity plants, bombs, submarines, ships and perhaps in the near future, cars. The energy produced as a result of fission and fusion is enormous. There is often confusion about the two processes that allow nuclear energy to be produced, however. The purpose of this report it to clarify the confusion and to shed light on this amazing source of power.

The History of Nuclear Science
The discovery of nuclear science occurred in 1895 when Wilhelm Roentgen discovered a new kind of ray he named “x-rays”. This discovery lead to others, such as the discovery of radioactivity in 1896 by Antoine Henri Becquerel, electrons by J.J. Thompson in 1897 and alpha and beta rays in 1899 by Ernest Rutherford. In 1900, Fredrick Soddy discovered the spontaneous decay of radioactive elements and called the byproducts “isotopes”. Albert Einstein’s Special Theory of Relativity (relating to the famous equation E=mc2) was published in 1905.
Niels Bohr, in 1913, published a combination of nuclear and quantum theories that is generally accepted in the science community. Experiments pertaining to radioactivity, the structure of atoms, and quantum mechanics have continued to today.
The most important advances in the history of nuclear science were made during World War II. President Roosevelt initiated the Manhattan Project, originally called the Manhattan Engineering District, on December 6, 1941. The purpose of the Manhattan Project was to create an atomic weapon before Germany did. The main centers of this project were in Los Alamos, New Mexico, Oak Ridge, Tennessee and Hanford, Washington with many experiments occurring in the Metallurgical Laboratory at the University of Chicago in Illinois. J. Robert Oppenheimer and Brigadier General Leslie Groves were in charge of this project. The culmination of these efforts occurred on July 16, 1945 in Alamogordo, New Mexico with the Trinity Test, the first explosion of an atomic bomb in the world.
After this, two atomic bombs, both fission bombs, were dropped on Hiroshima (August 6, 1945) and Nagasaki (August 9, 1945). The bomb dropped on Hiroshima is called “Little Boy”, and is a uranium bomb, and this caused between 80,000 and 140,000 deaths. A “Fat Man”, or plutonium, bomb was dropped on Nagasaki, killing around 74,000 people.
After the war, focus shifted to include the production of nuclear powered submarines, ships and power plants. Also, in 1950, President Truman authorized scientists to begin designing and building a hydrogen bomb, a fusion bomb, which was tested in 1954. The first nuclear power plant in the United States, built in Pennsylvania, began operations in 1957. Currently, there are 104 operating nuclear power plants in the United States.

Fission
Nuclear fission is the process by which nuclear reactors, bombs, ships and submarines are powered. It starts with either 235U (Uranium) or 239P (Plutonium), isotopes of the original element. Fission is the separation of one element, for example, Uranium, when it is struck by a free neutron and becomes unstable into two elements (such as 134Xe [Xenon] and 100Sr [Strontium]) with 1-3 free neutrons (in the case of 134Xe and 100Sr, there will be two neutrons), causing a chain reaction which can be controlled by what the reactor core is made out of. When controlled properly, fission creates a lot of energy (according to Einstein’s Special Theory of Relativity) and thus creates power for electricity generation, submarines and ships.
There are two main kinds of fission reactors in the United States – Boiling Water Reactors (BWR) and Pressure Water Reactors (PWR). They operate slightly differently, but both are just as effective in producing electricity. A new kind of plant, called a Pebble Bed Modular Reactor (PBMR), is being currently tested in South Africa and Germany, and a kind of car engine using this idea is being built and tested in Holland.
For an atomic bomb, it is necessary to have a critical mass, and more importantly, a supercritical mass, for the bomb to explode. A critical mass is the minimum amount of fissionable material necessary to maintain a chain reaction under specified conditions. For an explosion to occur, the system must be supercritical, meaning that it exceeds the amount of a critical mass for the material and circumstances. A bomb is built so that when released, the critical masses will be pushed together, creating a supercritical mass and an inevitable explosion.

Fusion
Nuclear fusion is the process of creating the energy that powers all the stars, including our sun. As of today, fusion is not cost effective for mass electricity production, but ongoing experiments are being conducted to make it cost effective. To produce fusion, it takes two isotopes of hydrogen, an 2H atom, also called deuterium, and 3H atom, also called tritium, and with the addition of extreme heat and pressure, it fuses them together to create the unstable 5H atom. Because it is unstable, it releases a neutron, and you are left with a 4H atom, free neutron and masses of energy.
Hydrogen bombs are about ten thousand times more powerful than atomic bombs. They are built so that the nuclei of hydrogen are joined together in an uncontrolled fusion reaction to release massive amounts of energy. This process is actually started by nuclear fission of the element lithium deuteride to create tritium, which fuses with deuterium, and begins the fusion process, which happens very quickly creating energy and heat allowing the bomb to explode.
As I stated before, fusion is not cost effective today, and several experiments are being conducted to try and make it that way. There are five operating reactors for fusion, the oldest is in Culham, England (near Oxford) and is called Joint European Torus, or simply JET. It has been operating since 1983. Here, a constant temperature of 40-50 million degrees Celsius is maintained in the core, or tokomak, and temperatures of over 300 million degrees Celsius have been achieved. It uses plasma coils to maintain these high temperatures and a vacuum vessel maintains the constant pressure necessary for fusion to occur. The record for fusion power is held by JET and is 16 megawatts, achieved in 1997. The other fusion reactors are in Canada, Germany, Japan and the United States.

Conclusion
As nonrenewable energy sources are diminishing, nuclear energy will be able to sustain us because it is environmentally safe, is relatively inexpensive to operate, boosts our economy, provides for national security and is the solution to the energy crisis in America. Nuclear reactors release very few pollutants, therefore they are environmentally safe. Due to the inexpensive costs and reduced imports from other countries, increasing domestic production and adding jobs, nuclear reactors are a boost to our economy. National security is improved because we will be importing less from volatile regions in the world.
Recent advances in technology, and those to come, are driving down the operational costs and have drastically improved the safety of nuclear reactors. Terrorism is not a major threat to the power reactors because of the amounts of security at these reactors. Nuclear fission is already cost effective, and nuclear fusion is well on its way to becoming cost effective. Advances continue to improve our knowledge of these processes, and show us how wonderfully God made the earth, not ignoring any details.

Glossary
Boiling-Water Reactor (BWR) – A reactor in which water is boiled directly in the reactor vessel.
Chain Reaction – A process taking place during nuclear fission in which one fission event releases neutrons and energy, causing another.
Fissionable Material –Any element capable of nuclear fission, e.g., uranium or plutonium.
Isotope – The term isotope defines atoms that have the same number of protons but a different number of neutrons; that is, they are atoms of the same element that have different masses.
Lithium Deuteride – Used as the fuel for the fusion bomb. A neutron is added to the lithium, producing tritium which is in turn fused with the deuteride and begins the chain reaction necessary for it to explode.
Nucleus – The nucleus is the center of an atom. It is composed of one or more protons and one or more neutrons. The plural form is nuclei.
Pebble Bed Modular Reactor (PBMR) – This kind of reactor is a type of advanced reactor called a high temperature gas cooled reactor. The uranium, thorium or plutonium fuels are in oxides contained within spherical pebbles made of graphite and an inert gas, such as helium, nitrogen or carbon dioxide, then circulates through the spaces between the fuel pebbles, carrying the heat away from the reactor to an electricity generator.
Plasma Coils – Plasma coils are used in nuclear fusion reactors to produce the high temperatures necessary for fusion.
Pressurized-Water Reactor (PWR) – A reactor in which neutrons heat pressurized water, which is then used to produce steam to run a turbine.
Radioactivity – The spontaneous emission of radiation from the nuclei of an unstable isotope, and the results of this emission convert the radioactive isotope into the isotope of a different element which may or may not be unstable. Ultimately, as a result of one or more stages of radioactive decay, a stable end product is formed.
Reactor – A facility in which fissile material is used in self-sustaining chain reactions (nuclear fission), and a reactor includes fissionable material such as uranium or plutonium, a moderating material, a reflector to conserve escaping neutrons, provisions for heat removal, and measuring and control elements.

Bibliography
WEBSITES:

http://www.atomicarchive.com/index.shtml
http://en.wikipedia.org/wiki/Main_Page
http://www.jet.efda.org/index.html
http://www.nei.org/index.asp
http://www.nmcco.com/
http://www.atomicheritage.org/home.htm
http://nuclearweaponarchive.org/Usa/Med/Med.html
http://www.iter.org/
http://www.romawa.nl/welcome.htmlhttp://www.atomicengines.com/