Nuclear Reactors

Because "ordinary" uranium is mostly 238U, which won't fission and create a chain like its lighter cousin 235U will. When critical mass is achieved with the 235U isotope of uranium, fission will occur spontaneously. Or with a significantly enriched uranium fuel (one where the natural concentration of 235U has been increased a bunch so the fuel has a much higher percentage of this isotope), fission and a chain reaction is also possible. But with just natural uranium, a big pile of it will just sit there. It won't fission and create a chain reaction. Note that 238U is radioactive and decays over time because it is unstable, but it has a long half-life. Also, the fact that it's unstable (radioactive) doesn't mean it's fissile. It isn't.

A nuclear fission reaction is controlled in a nuclear reactor by using control rods made of materials that absorb neutrons, such as boron or cadmium. By adjusting the position of these control rods within the reactor core, the rate of fission and thus the power output can be regulated. Inserting the control rods absorbs neutrons and reduces the number available for further fission reactions, helping to maintain a steady power level.

it comes from nuclear fission
Nuclear energy is the fission of certain, materials such as uranium or plutonium,within a nuclear reactor. This produces heat, which turns water into steam. This steam rises, driving a turbine which creates electricity for commercial and public use.

You don't need nuclear power, energy can be generated using other methods, fossil fuels, hydro-electric etc.

However nuclear power does reduce a countries reliance on fossil fuel, which can be particularly important for countries with few fossil fuel reserves of their own. Nuclear power stations do not release CO2 into the atmosphere so do not directly contribute to global warming. Many countries are looking at an investment in nuclear power to help meet CO2 emissions targets.

Nuclear power stations are also required to make plutonium for nuclear weapons. Plutonium does not occur naturally and can only be made from uranium in nuclear reactors. Any country with a nuclear weapons program will have a civilian nuclear power industry for this reason.

It's greener and safer than fossil fuel power plants, but produces far more energy than wind or solar power plants.

For example, coal power plants produce the same amount of radiation as Three Mile Island every few days, and produce extremely large amounts of particulate pollution, which kill the same number of people as Chernobyl every few weeks.

Wind turbines cost about the same amount as nuclear plants, per watt, but to produce the same amount of energy, they require 300 times as much land.

Spent uranium is usually reclaimed in thermal-neutron reactors.

This process is possible only in CANDU reactors and other similar types, which use heavey water as a moderator (a moderator slows neutrons to a speed at which they are more likely to be absorbed by a nuclei, as the neutrons impact the molecules of the moderator and are slowed).

Normal water (usually refered to as light water when dealing with nuclear reactors) is H20, H being a hydrogen atom, which does slow the neutrons, but it also sometimes absorbs neutrons that impact it. This means less neutrons are getting through to the reactor core, which means once a fuel bundle has less than a certain percentage of fissionable material left in it (idealy it should be about 5% for commercial reactors, that it, before it has been used. It can only continue to be productive in a light-water reactor above about 1- 2%.), not enough neutrons are getting through to keep the reactor critical (the point where enough neutrons are being released from fissions to sustain a chain reaction), and the fuel is discarded.

Heavy water, on the other hand, is D2O, with two deuterium atoms (an isotope of hydrogen which has 1 proton and 2 neutrons, instead of the regular 1 and 1). This means that the hydrogen atoms already have an extra neutron, making them less likely to absrob the neutrons they are supposed to be slowing down.

Thus more neutrons are getting through, and there are enough to cause fission in a significant portion of the remaining fissionable material, allowing such reactors to run on depleted uranium.

The energy in a nuclear reactor comes from nuclear reactions, specifically fission reactions where the nucleus of an atom is split into smaller parts. This process releases a large amount of energy in the form of heat, which is then used to produce steam to turn turbines and generate electricity.

The Open Pool Australian Lightwater (OPAL) reactor is mainly used to produce radioisotopes for medical use (nuclear medicine). It also performs irradiation services and is used for neutron beam research. Although the fission process does generate heat, the facility is not used to generate power mainly due to political reasons. Australia made the decision not to build power reactors, though there was at one time a proposal to build one at Jervis Bay.

Australia has a large amount of cheap black coal and generates most of it's power in coal burning power stations. The black coal is slightly more efficient than most of the world's brown coal.

The energy output of a nuclear reactor can vary greatly depending on its size and design. However, on average, a nuclear reactor can generate around 1-2 billion kilowatt-hours (kWh) of electricity in one day.

Mines, usually it is uranium, with only 0.7% (aproximately) U-235 (the isotope that is used for fission), the rest is U-238, known as depleted uranium, or natural uranium. Then it enriched to about 3-5% U-235, unless it is used in a CANDU reactor, in which case it can almost literaly be used straight out of the ground.

Using control rods that obsorb neutrons, and can be gradualy raised or lowered into the core. In emergencies, "neutron poisons" are used, which almost instantly stop most fission within the core.

Plasma is the form of matter found in lightning bolts, nuclear reactors, and stars. It is a state of matter that consists of charged particles, such as electrons and ions, and is characterized by its high energy and conductivity.

how the nuclear reactor can work?

A nuclear reactor is a system which generates a nuclear fission reaction. A nuclear reaction is a self-sustaining reaction where the output of one stage is the input of the next stage. Therefore, if there is enough fuel, the reaction will continue indefinitely.

The most common type of fission reaction is a Uranium 236 reaction. Nuclear fission involves splitting an atom into smaller atom(s). In a U236 reaction, Uranium 235 is the fuel. A neutron is propelled, which strikes the nucleus of a Uranium 235 atom, creating a U236 atom. U236 is highly unstable, and undergoes radioactive decay. This means the U235 atom turns into a Krypton atom, and a Barium atom, plus 2 extra neutrons and some energy. This energy is generally heat, and is absorbed by nearby water, which boils and turns a turbine.

The two neutrons continue the reaction by hitting another U235 atom (each).

There are other types of nuclear reactions as well, but the principle is the same. The output is generally atoms of different atomic mass, energy, and some other byproduct which will continue the reaction (e.g. an alpha particle - a Helium nucleus, or a neutron). In nuclear fission, the atom byproducts have a lower atomic mass.

In nuclear fusion, the atom byproducts have a higher atomic mass (since multiple atoms are fused together). Nuclear fusion is the basic power plant in the core of the sun (combining Hydrogen atoms into Helium, or Helium into Carbon, etc.). The byproduct here is the energy that we see as light.

Slow neutron fission chain reaction.

Most reactors use uranium fuel enriched slightly to about 3-4 percent U-235, in the form of uranium dioxide UO2. Some older reactors used metallic natural uranium, while some other reactors use plutonium or a plutonium-uranium mix as fuel.

Plasma is highly ionized atoms. This results in extremely energetic ions, and these ions carry an electrostatic charge. The tokamak is a container with magnetic fields for boundaries. The plasma is a moving group of electrostatic charges, and moving charges create magnetic fields. The magnetic field thus created interacts with the magnetic field set up in the tokamak to deflect and thus confine the charged plasma.

Nuclear power plants can generate electricity by using nuclear reactions to heat water and produce steam, which then drives turbines to generate electricity. This source of energy is generally considered low-carbon and can help reduce greenhouse gas emissions compared to fossil fuel sources. Additionally, nuclear power can provide a reliable and steady source of electricity, contributing to energy security and grid stability.

The development of nuclear weapons was a collaborative effort by several scientists working on the Manhattan Project during World War II. The key figures involved in this project were J. Robert Oppenheimer, Enrico Fermi, and the physicist Albert Einstein who wrote to President Roosevelt urging the research on nuclear weapons.

As of 2021, India has 22 operational nuclear reactors across seven nuclear power plants. India has plans to increase its nuclear energy capacity through the construction of additional reactors in the coming years.

Nuclear centrifuges are machines used to enrich uranium by separating isotopes. The centrifugal force causes the heavier U-238 isotopes to collect on the outer rim, while the lighter U-235 isotopes concentrate towards the center, allowing for enrichment. This technology is a critical step in the production of nuclear power and nuclear weapons.

Nuclear power creates jobs across various sectors, including engineering, construction, maintenance, operations, research, and support services. Specific job titles may include nuclear engineer, reactor operator, radiation protection technician, and waste management specialist. Additionally, nuclear power plants create indirect jobs in industries such as manufacturing, transportation, and supply chain.

No, the neutrons produced in nuclear reactors don't travel anywhere near the speed of light. Let's look at this a bit. In the "standard" fission reactor, fissile nuclear fuel is "started up" and the neutron chain reaction begins. Neutrons are produced during atomic fission events, and these neutrons are sometimes called "fission energy" or "prompt" or "fast" neutrons. They are the free neutrons that appear as the result of the fission event. And they're moving pretty darn quick when they're "blown out" of the fissioning nucleus. But they're not moving anywhere near the speed of light. The Boltzman distribution (a fancy way of speaking about the range of energies at which the fast neutrons appear), has a strong peak at close to 2 MeV (20 TJ/kg). That translates into a speed of 28,000 km/s. The speed of light is some 299,792 km/s as we've defined it, and that puts the speed of those fast neutrons at roughly 10% the speed of light.

I make it 104 on the NRC website (operating units, that is)

For water reactors the danger would be mainly from the high temperature, escaping water would flash to steam and scald anyone nearby.

CO2 cooled reactors would also present high temperature and risk of asphyxiation.

There might be some radioactivity, but not a huge amount as failed fuel would have been removed before it became high enough to be dangerous.

Of course if a Loss of Coolant (LOCA) occurred resulting in fuel failure, there might be more activity released, but design is aimed at preventing a LOCA, even in extreme cases such as an earthquake.