Nuclear Reactors

The first Indian nuclear reactor's name is APSARA.

This was part of the Manhattan Project in WW2 to develop the atomic bomb. You must remember that at that time science was being pushed hard to come up with answers in order to understand basic nuclear facts, with the aim of making a bomb. Nobody even knew if it was possible, but the US was afraid that Nazi Germany might get there first, so every avenue was looked at for answers. It was known that enriched uranium, in fact nearly pure U235 would be needed, and this was done by using the gaseous diffusion process with uranium hexafluoride. The other route, only known theoretically, would be to produce plutonium 239 by irradiating uranium 238 in a neutron flux. The way to get enough neutron flux was to produce a continuous controlled neutron chain reaction, and Fermi was the scientist who had the best ideas how to do this. The first 'pile' as it was called was the result, built in Chicago as an experiment to prove the theory. This used a graphite moderator and metallic natural uranium fuel. It worked as predicted, but to get enough plutonium something much bigger and more powerful was needed. The same type of reactors but more powerful were therefore built at Hanford in Washington State and these produced the plutonium used in the second atomic bomb (Nagasaki) The following para is taken from Wikipedia article on Manhattan Project:

The first major scientific hurdle of the project was solved on December 2, 1942, beneath the bleachers of Stagg Field at the University of Chicago, where a team led by Enrico Fermi, for whom Fermilab is named, initiated the first artificial self sustaining nuclear chain reaction in an experimental nuclear reactor named Chicago Pile-1. A coded phone call from Compton saying, "The Italian navigator [referring to Fermi] has landed in the new world, the natives are friendly" to Conant in Washington, D.C., brought news of the experiment's success.

The cost of a nuclear reactor is nuclear waste witch is produced by The reaction in a nuclear reactor happens because neutrons hit the nuclei of atoms, which can divide, producing energy, new atoms, and more neutrons.

When a neutron hits the nucleus of an atom, four different things can happen. In the case of most collisions with the nuclei of non-radioactive atoms and some radioactive atoms, the neutron imparts some of its energy to the atom and bounces off.

In some cases the neutron is trapped in the nucleus, changing the atom from its isotope to the next heavier isotope. This usually means the atom becomes less stable and will quickly decay or undergo fission.

In some cases the neutron simply causes the atom to decay.

In some cases the neutron causes the atom to undergo fission.

When an atom decays it loses mass and nearly always changes to a different element. Sometimes it emits an alpha particle and in so doing it drops 2 in atomic number and 4 in isotope. An example is when uranium-238 (atomic number 92) becomes Thorium-234 (atomic number 90)

Sometimes it emits a beta particle, and when this happens its atomic number increases by one, but the isotope number stays the same. An example is when thorium-234 (atomic number 90) becomes protactinium 234 (atomic number 91).

The decay of an atom is a long, multi-stepped process that ultimately ends with a radiologically inert isotope, such as lead-208.

Fission happens when the atom, such as uranium-235, is divided into two daughter atoms with a combined mass somewhat less than the original. This process is rather unpredictable as to what atoms are produced, but they are typically radioactive. An example is uranium-235 dividing to produce barium-141 and krypton-92 (notice these atomic numbers add to 233, slightly less than the uranium's number). The by products of fission are all waste, as are the atoms they decay into.

Nuclear waste is short lived, which usually decays in a spent fuel pool; medium lived, which usually decays in a couple hundred years; or long lived, which can last for millions of years. All of it remains dangerous as long as it is appreciably radioactive.

A breeder reactor is one that is designed to produce more fissionable fuel from material that is not initially fissionable, thus enabling a self-sustaining fuel cycle to be set up so that new supplies of the fissionable U235 are not needed (that is the concept).

Note that even the normal thermal (ie moderated slow neutron) type of reactor does breed fuel, in that some of the U238, which constitutes about 95-96 percent of the uranium used, is converted to plutonium. If the fuel is processed after unloading from the reactor, the Pu can be recovered, and a mixed oxide fuel produced (MOX) which contains Pu and U235, for subsequent use in thermal reactors. This has benn done in the UK and France, but in the US this has not been done on any large scale, the used fuel has been and still is being stored on the power plant sites.

However the concept of the breeder reactor as a new generation of reactors is aimed at using the fast reactor, that is one in which there is no moderator, the fission chain reaction is maintained by fast neutron fission. This requires a higher enrichment of fuel for its first load, this can be provided by Pu239, which is available from old nuclear weapons which have been taken out of service, and from chemical separation of used fuel as said above. Such a fast reactor can have an outer blanket of U238, which is available as a byproduct of the U235 enrichment process, and during operation neutron capture would convert this to Pu239 (together with higher Pu isotopes). This could then be recovered and used for subsequent fuel charges. Thorium is also a possible breeding material, producing U233.

These ideas have been tried in prototypes, some large enough to produce power (Dounreay PFR in UK, Phenix in France), with some technical success, but at the moment it is not commercially attractive, the thermal types of PWR and BWR are still the main intention for new builds, and this will probably continue while U235 supplies are plentiful and reasonably priced. At some fairly distant time the fast breeder may become the preferred commercial option, but not yet.

Substances commonly used as moderators in nuclear reactors include light water (H2O), heavy water (D2O), and graphite. These materials help slow down fast-moving neutrons to speeds at which they are more likely to cause fission in uranium fuel.

Water is the most common coolant used to remove heat from a nuclear reactor core. In pressurized water reactors (PWRs), water is used both as a coolant and as a moderator.

You are asking for a lot in one question! For thermal reactors there are replies available. Ask 'What are the advantages of nuclear fission power' and see the reply, there is also in the links section another reply to 'What are the disadvantages of nuclear fission power', so there is no need to repeat these.

Reactors specially designed for breeding are aimed at either producing plutonium from uranium 238, or uranium 233 from thorium. Various theoretical designs are possible, the difficulties are in the practical engineering, and of course the fuel separation which would be required to obtain the bred fuel. The most used design so far is the liquid metal (sodium or sodium/potassium mixture) fast reactor, which can breed plutonium from fast neutron capture in uranium 238. A fast reactor, that is one where the neutrons from fission are not slowed down by a moderator, is going to breed more Pu than a thermal one (with a moderator). Therefore water reactors are not suitable, as water moderates neutrons. If you know about chemistry, you will know how reactive sodium is, and if it is hot it is even more so, so it is potentially dangerous although the liquid metal does not have to be pressurised. But it has to circulate through heat exchangers to give its energy up to a steam/water circuit for power generation, so any leak there will result in water ingress to the reactor.

I think that at present there is no great incentive to press ahead with breeders, as PWR and BWR designs have been developed to be reliable workhorses and there is no shortage of uranium for enrichment. This could change in the future and breeders could come back, but mostly the impetus has gone, prototypes have been shutdown and building programs have been abandoned, though theoretical studies continue in some countries. India seems to be interested in the thorium cycle, but again I wonder if this will become reality, especially now with the US-India deal for co-operation, which will I expect deliver US water reactor technology to India.

To learn more see Wikipedia 'Fast Breeder Reactors', and also Dounreay PFR

At present, after a long period in which the Labour government set its face against nuclear, they have now said that a number of new units should be built, in view of the declining North Sea gas production which means the UK will have to import liquefied natural gas. The gas cooled reactor design has been abandoned and new ones will be PWR (or possibly BWR). Only one PWR was built at Sizewell, and the teams that built this have dispersed mostly, with the breaking up of the CEGB (the previous nationalised generating body). The most likely outfit to build new PWR's is the French company EDF with their reactor supplier Areva. However their bid to purchase British Energy, which owns some of the likely sites, has not been finalised. This has government support and probably will go through though not certain. Other suppliers may also join in the bidding, so nothing is certain yet. Talk is of about 8 new units total.

it is a device in which chain reaction is initiate or controlled $generate heat energy typcially for power

Dr. Klein was head of the team that designed Canada's first nuclear reactor during the 1940's. The reactor contributed to military inventions that were key in siding the Allies during the 2nd World War.

ADVANTAGES

1. releases large amounts of energy from small amounts of mass

2. very efficient

3. fuel lasts a long time

4. convert nuclear energy into thermal energy

DISADVANTAGES

1. they are very expensive

2. they are hard to keep up

3. the waste is hard to get rid of

One of the primary functions of a nuclear reactor is to maintain a chain reaction. Also, nuclear reactors are meant to provide a steady flow of neutrons.

Most nuclear reactors, in general, are designed and built to produce usable energy. The energy helps supply public demand for electricity, or provide propulsion for a combat vessel at sea, especially submarines. Some nuclear reactors are built for research only, to learn more about nuclear power and about better ways to utilize it. Nuclear reactors do not emit atmospheric contaminants like other energy-making processes do. They are not like combustion engines, and require no oxygen to burn for their function.

Breeder reactors are a different story indeed. They do produce usable energy, but in too many cases their design purpose is to "breed" more fissionable material during the reaction process.

Nuclear reactors use a type of fuel that can last much much longer than coal or gas or biomass fuels, and is much more clean, producing a comparitively tiny amount of waste which, although radioactive, can be properly handled and disposed of, and may soon even be able to be bred into non-radioactive elements.

Another advantage of nuclear is that it produces a vaste amount of energy compared to other forms of power generation. A pelet of uranium about the size of a "Mike & Ike" (or the gold part on the end of a pencil, for those not familiar with the candy) produces energy equivilant to several train cars full of coal.

One more advantage is that nuclear plants, unlike tidal power stations or dams, can be built anywhere, though they are more expensive than almost all other forms of power plants (though they do much more than pay for themselves in the long run).

The first inventor of a nuclear reactor was Enrico Fermi. Refer to link below.

Nuclear disasters are incidents that result in the release of radioactive material from a nuclear facility. They include both minor and major radiation releases.

Most nuclear fallouts were caused by mismanagement of a nuclear reaction/reactor (such as chernobyl), though the Japanese fallouts were the cause of a last ditch effort to cripple the Japanese in their efforts to aid their coalition, the Axis of Evil, to which our current president has often made mention.

A nuclear reactor requires the neutrons released from one reaction to trigger the fission of other nuclei. Control rods are required to absorb some of these neutrons so as to prevent a runaway chain reaction.

A nuclear power plant can cause catastrophic damage if a meltdown occurs, releasing dangerous levels of radiation into the environment. This can lead to long-term health implications for people living nearby and result in environmental contamination. Additionally, accidents at nuclear power plants can have far-reaching economic consequences and require extensive cleanup efforts.

The part of a nuclear reactor in which the fuel is located is called the core. This is where the nuclear fission reactions take place, producing heat that is used to generate electricity.

I suggest you would need to ask one of the companies operating nuclear plants. "The short answer is, "it depends." NRC licensed reactor operators employed with public utilities generally make $40-$45/hour, more or less, depending on location. Including overtime, shift differential, and bonuses; most ROs can expect to make well over $100k/yr. Senior reactor operators (those with an SRO license) are usually salaried employees (no OT) and may make about the same as an RO, possibly more, possibly less.