potential benefit of nuclear energy

Priority: Ensure safe and advance technology utilized for peaceful use.
Less Carbon Dioxide and global warming and other benefits.

You can pick and list the advantage and disadvantages...try to read and list 2 columns:

*****

Only 30 years ago, nuclear energy was an exotic, futuristic technology, the subject of experimentation and far fetched ideas. Today, nuclear energy is America's second largest source of electric power after coal. More than 110 nuclear energy plants supply more electricity than oil, natural gas or hydropower. Since 1973, they have saved American consumers approximately $44 billion, compared to the other fuels that would have been used to make electricity. Since our electricity system is interconnected, practically every American gets some electricity from nuclear energy. In addition to the economic benefits achieved through the use of nuclear energy, there are environmental benefits as well. There are, however, various drawbacks caused by the production of electricity through nuclear power. Although there are various risks involved when using nuclear energy as a source of power, we argue that the benefits greatly outweigh any potential problems that may arise.

The use of nuclear reactors to generate electricity continues to increase all over the world. By December of 1979, about 128,000 million watts were being generated by 249 reactors operating in 22 countries.

Before we can truly understand how a nuclear reactor works, we must first examine the processes that occur in its core. In order for a reactor to work there needs to be at least one free neutron per fission. Nuclear reactors are fueled by uranium or plutonium in a solid form. They are ceramic pellets approximately the size of the end of your finger. These pellets are placed into 12 foot long, vertical tubes, which are bundled together and placed underwater inside the reactor. When the plant starts up, neutrons are let loose to strike the uranium atoms or the plutonium atoms. When the neutrons hit either of these types of atoms in pellets, the atoms split to release neutrons of their own, along with heat. On average 235U and 239Pu yield two free neutrons. Initial fissioning of 235U produces neutron energies of 2 Mev. To convert to more everyday units, this is equal to approximately 3.2 x 10-11J. These neutrons must be slowed down in order to increase the fission probability in the core of the reactor. The way in which these neutrons slow down is by hitting something that has approximately its own mass. Water is effective at slowing down neutrons. Once the neutrons slow down, they go back into Uranium and fission probability increases considerably. Heat is then transferred from the core of the reactor to the water and then induces steam.
Sometimes a neutron and proton will combine and produce a deuteron and therefore that neutron is now lost. Companies use heavy water in order to alleviate this dilemma. Some neutrons are captured directly by 235U or 238U and gamma rays are emitted. Some neutrons simply escape form the core altogether. These are considered fast neutrons. These fast neutrons have the ability to produce a fission reaction with 238U to produce heat and more neutrons. 239U could also be produced if 238U were to capture a slow neutron. The product rapidly decays into 239Pu. 239Pu has a greater fission probability than 235U, hence as 239Pu builds up, it fissions and contributes fuel (neutrons) to the reactor. Control rods absorbs neutrons in order to keep the number of neutrons, and therefore, the reactions are controlled. They are usually made of boron steel or graphite, since they are high neutron absorption material.

Pressurized water reactors and boiling water reactors are the two major types of generators that the US. uses to produce electricity. Pressurized water reactors consist of a single fuel element assembly of up to 200 zircaloy cadded fuel 'pins'. These 'pins' are immersed in a large steel pressure vessel containing ordinary 'light' water. The light water serves as both a coolant and moderator. Light water has a higher neutron-absorbing capacity than heavy water (D2O). This causes it to increase the percentage of 235U in the core. Uranium dioxide is a source of fuel for this reactor. The pressure vessel consists of control rods that pass through the lid, the light water under pressure, and the reactor core. The water attains a temperature of approximately 270 C without boiling, due to a pressure of about 13.8 to 17.2 MPa. This pressure is maintained through a pressurizer. The 'light' water passes in a closed circuit to a heat exchanger. This causes the water in the heat exchanger to heat up and convert to steam. This steam drives one or more turbine generators, is condensed, and pumped back to the steam generator. Another stream of water from a lake, river, or cooling tower, is used to condense the steam. It is necessary to shut down the reactor completely, remove the lid, and replace an appropriate portion of the fuel pin assembly, in order to refuel it, which occurs every 12 to 18 months

A more efficient way of removing heat is allowing water to boil. The boiling water reactor allows the coolant within the reactor core to boil. The steam generated is then separated, dried, and passed directly to the turbine generators. After going through the generators, the steam is condensed and passed back into the reactor core. Like the pressurized water reactor, the boiling water reactor fuel is 235U, enriched as uranium dioxide. In addition, the steam collection also occurs on top of the reactor. One other thing the boiling water reactor has in common with the pressurized water reactor is that it must be shut down for refueling. (see above figure)
As far as safety is concerned, the entire reactor is housed within a primary containment chamber which incorporates, underneath, a large ring-shaped tunnel somewhat filled with water. If any water or steam were to escape, it enters this tunnel, and condenses. In addition to this tunnel, there are several emergency systems in place.

Protecting Our Environment:
Nuclear energy plants produce electricity through the fission of uranium, not the burning of fuels. Consequently, nuclear power plants do not pollute the air with nitrogen oxides, sulfur oxides, dust or greenhouse gases like carbon dioxide.
America's nuclear energy plants reduce electric utility emissions of greenhouse gases by 20 percent, or 128 trillion tons per year. Without our nuclear power plants, electric utility emissions of nitrogen oxides would be 2 million tons per year higher. Emissions of sulfur dioxide would be 5 million tons a year higher. Thus, nuclear energy has drastically cut our dependence on foreign imported oil.
In France for example, from 1980 to 1986, SO2 and NOX emissions in the electric power sector were reduced by 71% and 60% respectively, causing reductions of 56% and 9% respectively, in total SO2 and NOX emissions in France (Trudeau 160).
Nuclear energy also offers an alleviation of the global carbon dioxide (CO2) problem that the world can do without. About 1,600 million tons of CO2 annual emissions would have resulted if 16 percent of the world's electricity now generated by nuclear power were to have been generated using coal. This is a significant amount. In fact, it is 8 percent of CO2 now emitted annually from the burning of fossil fuels.