Nuclear World

Topics to be covered:-1. Nuclear fission

2. Nuclear fusion

3. Nuclear Fuel

4. Atom bombs

5. Nuclear Power stations

6. Nuclear waste

7. Controlling rate of reaction

8. Benefits of fission

9. The fusion Bomb

Nuclear fissionIn one of the most remarkable process in nature, a slow neutron can be captured by a uranium-235 nucleus, rendering it unstable toward nuclear fission. A fast neutron will not be captured, so neutrons must be slowed down by moderation to increase their capture probability in fission reaction.A single fission event can yeild over 200 million times the energy of the neutron which triggered it!!!!!!

Fission reaction

Nuclear fusion

Nuclear fusion is the energy source of the future. It is what provides the sun and the stars with the energy to shine continously for billions of years. Fusion has been used here on earth to produce nuclear bombs,but has not yet been controlled yet so that we can obtain useful energy.We will try to show how fusion works, and describe current efforts to tame this limitless energy source.

The first generation fusion reactors will use deuterium and tritium for fuel because they will fuse at a lower temperature. Deuterium can be easily extracted from seawater, where 1 in 6500 hydrogen atoms is deuterium. Tritium can be bred from lithium, which is abundant in the earth's crust. In the fusion reaction a deuterium and tritium atom combine together, or fuse, to form an atom of helium and an energetic neutron.

It only takes a small amount of these isotopes to produce a lot of energy! The deuterium-tritium fusion reaction results in an energy gain of about 450:1!! No other energy source we can tap releases so much energy for the amount that is input.

Nuclear fuel

Some of the most commonly used elements are:-

1. uranium-235

2. Plutonium-238

3. Lithium (tritium source)

4. And some other elements

When uranium-238 absorbs a neutron it turns into uranium-239 and this decays by giving out beta radiations to form neptunium-239, which in turn decays again by beta radiations to form plutonium-239. Plutonium also undergoes fission and can be used as a fuel and also in the manufacturing if nuclear weapons. In this way, as the uranium-235 is used up, it actually makes plutonium-239. This can be extracted and used for subsequent energy production or bombs.

The fissioning of uranium-235 in the reactor of a nuclear power plant produces two to three neutrons, and these neutrons can be absorbed by uranium-238 to produce plutonium-239 and other isotopes. Plutonium-239 can also absorb neutrons and fission along with the uranium-235. Plutonium fissions provide about one-third of the total energy produced in a typical commercial nuclear power plant. The use of plutonium in power plants occurs without it ever being removed from the nuclear reactor fuel, i.e., it is fissioned in the same fuel rods in which it is produced.

Atom BombsAn atomic bomb is an explosive device in which a large amount of energy is released through nuclear reactions. This makes an atomic bomb, more properly called a nuclear weapon, a much more powerful device than any conventional bomb containing chemical explosives.

There are two types of nuclear weapons

1. Fission weapons

2. Fusion weapons

Nuclear Power Stations

There are many different designs of nuclear reactor but they all have a nuclear reaction at the core.The energy is released when the nuclei splits is given to the fission fragments.

There are 400 nuclear power plants worldwide in 2009, and those plants supply 16 percent of the world's electricity. France is far and away the leader in this regard, as nuclear plants produce 80 percent of that country's power. In the United States, 104 nuclear power plants produce 20 percent of all electricity. Thirteen of those plants are in Illinois, the most of any state.

Its Envinronmental

ImpactNuclear energy accounts for 73% of total electric power generation in United States. Even its envinronmental impact is not so long lasting as most of its waste byproducts are buried underground.

How is power created The fission of an atom of one atom of uranium can create as much energy as 10 million times one atom of coal can produce. One ton of uranium can produce more energy than several million tons of coal or several million barrels of oil.

Nuclear WasteNuclear waste are those that contain radioactive materials. These byproducts which are released are hazardous to human health and enviornment.

Radioactivity diminishes over time. So some of the waste can be stored until no longer it poses a problem.Low level waste with low level of radioactivity can be stored only for days or weeks but on the other hand high level waste with high level of radioactivity have to be store for month or thousands of years.

There are numerous sites that contain or are contaminated with radioactivity. Despite copious quantities of waste, the Department of energy has stated a goal of cleaning all presently contaminated sites successfully by 2025.

Benefits of fissionThe biggest advantage is that it is an established way to generate electricity without emitting carbon dioxide. This is more and more important as global warming becomes a real threat to the environment.

It also does not emit other pollutants into the air, such as smog or particulates.

nuclear power production does not contribute any harmful gases to the atmosphere. no carbon, no acid, no sulfur. It is safe, contained, and can produce as much as 5 lbs. of coal with a fuel pellet weighing 6 grams!

The advantages are that nuclear power plants make 33% of the United States electricity. They also make 15% of the world's electricity. The good thing is that to make all this electricity they don't burn anything like coal or wood. This means they don't pollute the air so it keeps the environment clean near the plants. In fact they have discovered that many endangered species of animals live very near to the power plants. Nuclear energy is the most concentrated energy on the earth so we can control it very well. This is good because rarely an explosion will occur. A nuclear power doesn't take up a lot of room so people can make a lot of these machines all over the earth to make electricity.

Fusion BombA fusion bomb is a nuclear explosive that is powered by a hydrogen fusion reaction. The force is much greater than that of a conventional nuclear fission bomb. The main material used for fusion bombs is the tritium isotope of hydrogen. This is because hydrogen is the atomic element with the lightest weight. This makes it an ideal fusible material for a bomb.

It is actual a fission assisted fusion bomb. That is because most hydrogen bombs are of the Teller Ulam design. This is a design where a bomb is detonated in stages. The first stage or primary explosive is a conventional nuclear fission bomb. This is triggered and the fission of the uranium releases neutrons and heat.

The first fusion bomb ever detonated was “Ivy Mike” in 1952 at the Enewetak Atoll in the Pacific Ocean. The bomb though it only a first attempt produced a yield 450 times more powerful than the nuclear bomb that was dropped on Nagasaki. The largest hydrogen fusion bomb ever detonated was Tsar Bomba a Russian bomb that was detonated in 1964.

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-Shanil savla

IBDP-1