Nuclear Reactors

Uranium and Plutonium atoms require nuetrons moving at a certain speed, with a certain amount of kenetic force, to fission properly and often, and to achieve this speed, a neutron moderator is placed between the neutron source and the fuel, which slows the neutrons down by causing them to hit its molecules. Water is often used, since the energy transfer is much more efficient, as hydrogen atoms are almost identical in size to neutrons, possesing only one proton (like two billiard balls striking each other), but hydrogen atoms sometimes absorb neutrons, meaning less get through to cause fissions, and once the concentration of fissionable material drops blow a certain percentage (usualy somewhere around 5%) fission is no longer maintainable. Heavy water posses hydrogen atoms with one extra neutron, so althought the energy transfer is slightly less efficient than with hydrogen atoms, there is much less chance of the atoms abosorbing neutrons, and so many more neutrons get through, allowing the reactor to run on fuel with much lower concetrations of fisionable material (even as low as 0.7%, the natural level of U-235 in Uranium ore). Thus somereacotrs using heavy warer as a neutron moderator (such as the CANDU) can even run on the waste from other, "light water moderated" reactors (light water is just another name for normal water, as opposed to heavy water).

It is the moderator in a nuclear reactor that is used to slow neutrons down in a thermonuclear reactor. The moderator, which is often water, slows the neutrons by providing a "target" for the neutron to slam into. The resulting collision (called a scattering event) will allow the moderator to absorb some of the kinetic energy from the neutron, and that neutron will come away at a lower velocity than it did coming in. The hydrogen in water (it's H2O) has, in most cases, a single proton in its nucleus. As the proton in a hydrogen nucleus has approximately the same mass as a neutron, there will be, in general, a larger amount of energy stripped from the neutron in a given scattering event. (If you consider, say, a scattering even between a golf ball and a bowling ball, the golf ball won't lose much energy to the bowling ball. But if the golf ball undergoes scattering with another golf ball, there is a "better" result and more slowing of the neutron.)

In addition to the use of water (both light and heavy water) as a moderator, we also find that graphite (an allotrope of carbon -- pencil lead) and liquid metals are also used as moderators. The same idea applies, and the moderator, whatever one it is, provides a target for higher energy neutrons to slam into. The result of the scattering events is that the neutrons are slowed in the process.

The material used to slow down high-speed neutrons in a reactor is called the moderator. The moderator in a pressurized water reactor is the water, which is the main coolant. Collisions between the neutron and hydrogen nuclei (protons) slow the neutron down (thermalizing it) and increasing the probability that it will be absorbed by another fissionable atom. That makes the chain go, it maintains the chain reaction. Slowing down neutrons does NOTslow down the process of nuclear fission. If anything, it maintains it or speeds it up because slower moving neutrons have a higher probability of being absorbed and continuing or building the chain reaction. A link is provided.

The thick steel vessel is to contain the high pressure of the water in the reactor, the concrete is to provide radiation shielding, for the operating crew mainly but also to prevent outside equipment from becoming irradiated

Nuclear fission is used in nuclear weapons to create what some might call an atomic blast (nuclear blast). Nuclear fission used this way can also be applied in special complex designs to generate enough thermal energy (heat) to initiate a fusion reaction. This creates an even bigger nuclear blast.

Depends on the size of the city, but probably yes, in fact why not for a year

I guess it's the strongest form of structure to form the end of the upright cylinder which is the basic reactor enclosure. The reactor must be enclosed with a structure which can contain the worst type of reactor failure which would release a lot of steam. It also protects the reactor and its equipment from the weather.

1. it is a clean source of producing energy and doesn't cause CO2 or greenhouse gas emissions.
2. It is safer than other fossil or renewable energy sources.
3. it could be used for medical treatment.

Based on current events and researched gathered by IAEA: an exposed core, with unusable fail safes (to cool the reactors) as well as assuming staff are continually dosing the external housing with a coolent (i.e. salt water), you may believe it may take just a number of days to advert a nuclear catastrophe and cool down the reactor, right? Unfortunatley, the reality looks very grim. Without a proper circulation of coolent WITHIN the reactor, the build-up of hydrogen atoms and water vapor would expose the fuel-rods that would create am imminent partial-meltdown, assuming all fail safes are still non-functional/ Unlike chernoybl, technology has improved greatly, however, the heat generated from the fuel rods are capable to slice through the housing similar to that of melted butter exposing the core to the atmosphere. (i.e. Swiss cheese) Assuming the worse, an individual reactor in no way could generate the same nuclear fall-out as Chernoybl, however, with four reactors on the verge of a partial-meltdown and assuming these cores are exposed to the atmospehere in a partial-meltdown the catasrophe would be similar to that of chernoybl. The time frame you can expect a disaster of this magnitude to be adverted would be roughly * 2 - 4 weeks depending. However, you can expect the nuclear fall-out to be contained not anytime soon. If I were to make an educated guess with the clean-up process and containment, you would be looking at roughly 1 year. Worse case scenario would contaminate an area the size of the state of Maine, USA partiallu unusable for hundreds of thousands of years.* This worse case scenario would be approx half as destructive as Chernobyl.

The radiation shield used on a large scale for fixed shielding is concrete. This is effective because the large mass of concrete absorbs gamma radiation well, and as it contains a lot of water molecules it also stops neutrons from penetrating.

Because there isn't supposed to be. It's bad when we see nuclear power plants release steam unless they are just venting the secondary system, blowing down vents, or testing valves or systems. Let's think this through. The really big "towers" at Three Mile Island (TMI) are the evaporative cooling towers for the plant. Water is cooled by evaporation in the towers and this cool water is (primarily) used to cool the main condensers below the steam turbines in the generating plant. If the weather conditions are right, water vapor can be seen rising from the "big towers" at the plant and it looks like steam. But it's really water vapor. Nothing more. It's normal. Note: There is a fine line between steam like that coming out of a tea kettle and water vapor like in a cloud. But it's pretty much the same thing - condensing water that can be seen. The difference may be that the steam is created through elevated temperatures while the cloud is just a "low temperature" product of weather related activity. A link is provided to a picture of the TMI complex, and water vapor can be seen rising from the cooling towers of the Number 1 unit. Number 2 is shut down and it's reactor core is a wreck. It's towers are not going to be showing any activity.

Yes

Just like a line reactor..

A 3-phase Line Reactor is a set of three (3) coils (also known as windings, chokes or inductors) in one assembly. It is a series device, which means it is connected in the supply line such that all line current flows through the reactor, as shown below. Line Reactors are current-limiting devices and oppose rapid changes in current because of their impedance. They hold down any spikes of current and limit any peak currents. This resistance to change is measured in ohms as the Line Reactor's AC impedance (XL) and is calculated as follows: XL = 2 π f L (ohms), where: f = frequency in hertz (cycles per second) harmonic frequency examples: harmonic (60 Hz)frequency (Hz)5th3007th42011th660 L = reactor inductance in henries (H), millihenries (mH) -- H x 10-3, microhenries (µH) -- H x 10-6 By inspection of the XL formula, the Line Reactor is directly proportional to the frequency (f) and the inductance (L). That is, if the impedance of a Line Reactor is 10 ohms at 60 Hz, then at the 5th harmonic (300 Hz) the impedance is 50 ohms. If the inductance (L) is increased, then the impedance will increase proportionally. This increase in Line Reactor impedance will reduce the current in the line. The higher the frequency (Hertz), the lower the current. A Line Reactor's DC resistance (R-ohms) is very low by design so that the power losses (watts-I2R) are low. Line Reactors are rated by % impedance, voltage and current. However, they are sized by % impedance, voltage and motor horsepower. The motor horsepower determines the necessary current rating for the Line Reactor. Line Reactors are rated by impedance, voltage and current. # Impedance (% impedance of load Z)

The load impedance (Z) is calculated by this formula:

Z = V/I, where Z = load impedance (ohms), V = line voltage (volts), and I = line current (amps)

This percent of load impedance also determines the voltage drop across the Line Reactor. For example, a 5% Line Reactor would have a 5% voltage drop. # Voltage rating

Since a Line Reactor is a current-sensitive device, the voltage rating is needed for dielectric concerns as a maximum voltage and horsepower. It is also used to determine the current rating when given only voltage and horsepower. # Current rating (amperes)

This is the current required by the load(s). It is total current flowing to the load(s) and through the reactor. This current is measured in amperes (amps).

It was 1000 megawatt electric (RBMK-1000)

Yes, it is the main moderator function in what is called "thermal nuclear reactors"

The Russians are working on the problem of creating a nuclear reactor fuel out of americium, but they're still working the problem. In addition, they haven't built a reactor that uses americium as a nuclear fuel yet, either.

It is not true that:

Carbon dioxide is produced during nuclear reactor operation or during nuclear fission.

Something which may happen in the future, at present it is only an experimental equipment which absorbs more energy than it produces. The most promising type is the tokamak, which you can look up in Wikipedia.

Through the conversion of mass to energy.