Nuclear Fission

Basically ...

You fire electrons at a piece of uranium, which creates heat (or thermal energy). This heat is used to heat water up, which turns it to steam. This steam is then used to turn a turbine, which allows electricity to be created.

Fission products and unused fuel were lofted by the smoke of the burning graphite moderator. This fell back down as fallout (not much different from fission bomb fallout, although no nuclear explosion was involved).

Nuclear fission happens spontaneously in nature. Uranium-235 does this, and is the only commonly occurring natural isotope that does.

Nuclear fission can be induced by crashing a neutron into a fissionable atom. Some things other than Uranium-235 are fissionable, notably Uranium-238. Fission has been induced in various experiments. It happens in nuclear reactors and in nuclear bombs.

Nuclear fission was used in the atomic bombs dropped on Hiroshima and Nagasaki during World War II, leading to devastation and loss of lives. It was also harnessed for energy production in nuclear power plants, providing electricity to communities around the world.

It is not bad to generate electricity using nuclear power. However, there are concerns some people have with nuclear power, in particular with the side effects of it. In the process of generating electricity nuclear fuel is used up and left as what is called nuclear waste. This waste is very radioactive and a danger to living things for upwards of 10000 years. This waste must be stored, and debates about where and how it should be stored can lead people to consider nuclear power to be a "bad" method of generating electricity.

Temperature of the UO2 fuel must be kept below melting point of 2800 deg C. UO2 is not a good conductor of heat and the design parameters of max heat rate and fuel pin diameter have to be optimised to give a satisfactory operating condition.

A typical nuclear fission equation can be written as: ( \text{Uranium-235} + \text{Neutron} \rightarrow \text{Krypton} + \text{Barium} + \text{Neutrons} + \text{Energy} )

Uranium is the only naturally occurring element used for nuclear fission in commercial nuclear reactors. It is typically found in two isotopes, uranium-235 and uranium-238, with uranium-235 being the primary isotope used for nuclear fission reactions.

Involving fission & fusion at the same time? These reactions are completely different from each other and have no physical or mathematical relationships. I suppose you could claim that a hydrogen bomb that uses a fission trigger is an example of such an equation, however, the fission occurs before the fusion, so they are still separate and distinct from each other. The mass-energy equivalence equation, E=mc^2, is used to calculate the energy released due to the missing masses found in the fission or fusion calculations, but it comes at the end to convert the mass result into energy only.

Hydrogen is not changed into helium in nuclear fission. In nuclear physics, nuclear fusion is a reaction in which two or more lighter atomic nuclei are forced together and are fused into a heavier nucleus. In the case of the formation of hydrogen into helium, our sun does that in what is called the proton-proton reaction.

The use of nuclear energy in civilian society is to generate electricity. In the military it is to make bombs (and hopefully not use them). There are also some uses in medicine where radio isotopes can be used for diagnosis and treatment. These isotopes are produced by irradiation in low power reactors which enable short lived radio isotopes to be obtained as required.

A fission reaction diagram typically shows a heavy nucleus (like Uranium-235) being struck by a neutron, resulting in the nucleus splitting into two lighter nuclei, along with the release of additional neutrons and energy. This process is the basis for nuclear power generation and atomic bombs.

the absorption of a free-moving neutron by the atom's nucleus

The sun's nuclear fusion occurs in its core, where high temperatures and pressures allow hydrogen atoms to combine and form helium, releasing energy in the process. This energy is what fuels the sun and provides heat and light to our solar system.

The amount of energy released during nuclear fission reactions is primarily determined by the mass difference between the initial nucleus and the fission products. This mass difference is converted into energy according to Einstein's mass-energy equivalence principle (E=mc^2). Additionally, the way in which the fission process is initiated and controlled can also impact the amount of energy released.

Nuclear fission reactions in certain atoms can be initiated through processes such as bombarding the atoms with neutrons or by using controlled conditions that allow for the splitting of atomic nuclei. These processes can trigger a chain reaction leading to the release of energy, which can be harnessed for various applications, including nuclear power generation.

A Uranium or Plutonium nucleus fissions (whether in bomb or reactor) by capturing a neutron and entering an unstable excited state. This excited state releases its excess energy a couple nanoseconds later by splitting into two pieces, one about 1/3 and the other about 2/3 the mass of the original nucleus, and 2 or 3 neutrons.

It is related to the specific nuclear reactor design including the nuclear fuel amount and the reactor control system and the energy extracting medium (coolant) capacity.

1 BTU = 1.055 kilojoules. For a nuclear plant with an electrical output of say 1000 MWe, the reactor thermal output will be about 3000 MW (at 33 percent efficiency), or 3000 Mega joules/second, which is 3000 x 1000 kilojoules/sec, or 3000/1.055 x 1000 BTU/sec. this reduces to 2.84 x 106 BTU/second, Scale it according to the actual electrical output of the plant.

The only practical choice initially is Uranium-235, which occurs at 0.7 percent in natural uranium, the rest being U-238. U-235 is fissile, whilst U-238 is not. Reactors using natural uranium have been built but need either graphite or heavy water for the moderator. The US has used another route which is to enrich the uranium to 4 to 5 percent and use light water as the moderator, and most countries are now following this type of reactor, as enrichment costs using centrifuges are now much reduced.

During burnup of the fuel some of the U-238 is conerted to plutonium, which does not occur in nature. Pu-239 is also fissile and can therefore be used in replacement fuel, but it has first to be separated out from the used up initial fuel by a chemical process. In Europe this has been done and a mixed oxide fuel produced (MOX) which contains both U-235 and Pu-239. I think the US will also do this in the future, but probably using ex military sources for the Pu.

Another route is to irradiate Thorium to produce U-233 which is fissile and then separate that chemically. This is possible but has yet to be done on a commercial scale, and it is not yet economically worthwhile, though some countries with a lot of thorium have interest in the method.

Nuclear processes that can release large amounts of energy.

The fuel most commonly used in fission reactions is uranium-235. This isotope undergoes nuclear fission when bombarded by neutrons, releasing energy in the process.

Burning wood, cooking food on a stove, and rusting metal are all examples of chemical reactions that are not examples of nuclear fission. Additionally, photosynthesis, respiration, and fermentation are biological processes which do not involve nuclear fission.

Uranium-235 consists of 92 protons and 143 neutrons in its nucleus.