Nuclear Fission

For fusion, the main disadvantage is that nobody has been able to make it work. However it does have promise and if it can be developed it will not produce the dangerous fission products that fission does.

For fission, see reply to question 'What are the disadvantages of nuclear fission power'

The consequences of nuclear fission for the Earth include the potential for environmental contamination if radioactive materials are not properly contained, long-term storage challenges for radioactive waste, and the risk of accidents or meltdowns at nuclear power plants. Additionally, nuclear fission contributes to the proliferation of nuclear weapons, which poses a global security risk.

Two dangers associated with nuclear fission are the risk of nuclear accidents, such as the Chernobyl or Fukushima disasters, which can release radiation into the environment and pose health risks to people nearby. Another danger is the potential for proliferation of nuclear weapons if nuclear materials are not properly secured.

Fusion is the process that powers the Sun and other stars. In the Sun's core, hydrogen nuclei combine to form helium, releasing energy in the process. Nuclear fission, on the other hand, involves splitting of heavy atomic nuclei and is not the primary energy source of the Sun.

The results are not always the same, what is actually produced varies from one nucleus to another, so the result can only be represented statistically. There is one peak at around atomic mass of 100 and another at around 135. See the link below for a graph and more details

The basic concept is that certain heavy nuclei, notably uranium 235 and plutonium 239, can be split or fissioned by capturing a neutron, giving rise to other lighter nuclei, further neutrons, and released energy. By careful arrangement of the nuclear fuel a chain reaction can be produced which is self-sustaining and produces a lot of thermal energy. See the link below for more reading

Nuclear fission is a process where the nucleus of an atom splits into two or more smaller nuclei, releasing a large amount of energy. This process is the basis for nuclear power plants and nuclear weapons.

Fusion is harder to control/contain than fission.

The Sun is fusion energy and we are 150 000 000 kilometers away, it is still dangerous to be exposed to that radiation for many consecutive hours. Inside the Earth, and many rocks, have ongoing fission and it is no trouble to live on the surface of this planet.

Only because you can put an unlimited amount of fusion fuel in a bomb (unlimited yield), while more than a certain amount of fission fuel in a bomb will trigger predetonation and a fizzle (negligible yield) probably killing the people assembling the bomb with neutron radiation (not the blast).

The energy released per fusion event is less than 1/10 of the energy released per fission event.

This statement is incorrect. The products of nuclear fission of uranium are typically highly radioactive, including elements such as cesium, strontium, and iodine. These radioactive byproducts require proper handling and disposal to prevent harm to human health and the environment.

* There are now some 435 commercial nuclear power reactors operating in 30 countries, with 370,000 MWe of total capacity.* They supply 16% of the world's electricity, as base-load power, and their efficiency is increasing. Source: www.world-nuclear.org

Nuclear fission is quite simply when an atom is split. It is done my hitting atoms with other atoms so they break up into their individual particles. This can be used as a reliable energy source, as when nuclear fission occurs there is a huge release of energy. This is because when split into it's individual particles, an atom does not require energy to hold it together any more, so this energy has to go somewhere and is released. Nuclear fission is used to generate power in nuclear power plants by causing fission in the midst of other atoms. when the atom is split it's particles hit other particles and causes more fission to take place. This is known as a chain reaction.

The initial release of energy is in the form of kinetic energy of the fission fragments, but they are quickly stopped inside the fuel and the energy appears as heat, which is then passed into the coolant, whether water or gas.

the "disappearance" of a small amount of mass. Most of the energy from nuclear fusion of deuterium and tritium, which is the most likely reaction to be harnessed by man, is given off as kinetic energy of the neutrons formed. This is one of the problems involved-how to make use of this energy, even when the plasma can be contained and made to fuse, which has only been achieved for brief bursts so far. The neutrons will have to be stopped in some material surrounding the plasma to produce heat, but what material will stand up to these conditions is not clear.

In nuclear fission most of the energy appears first as kinetic energy of the fission fragments, which are then stopped in the fuel resulting in heat being generated which can be removed by the coolant, water or gas. There is also some gamma ray energy released.

Nuclear fission can be used in destructive ways, such as in atomic bombs where a chain reaction is initiated to cause a powerful explosion. Additionally, nuclear fission can be used in nuclear reactors to produce energy for electricity, but if not controlled properly, accidents like meltdowns can occur, leading to environmental and health hazards.

Energy comes from the nuclear fusion of hydrogen atoms to form helium atoms in the core of stars, including our sun. This process releases a tremendous amount of energy in the form of light and heat.

All reactors require some form of controllable neutron absorber to accommodate power changes, which cause changes in the concentration of fission product neutron poisons such as Xenon, and to accommodate fuel burn up caused reactivity changes. The reactor must be held at criticality during steady operation and very near it during slow power changes, and moveable control rods are provided for this, usually containing boron which absorbs neutrons strongly. When the reactor is tripped or scrammed the rods drop fully in, and start up requires a slow careful approach to criticality.

The following applies to PWR's and is taken from Wikipedia

Generally, reactor power can be viewed as following steam (turbine) demand due to the reactivity feedback of the temperature change caused by increased or decreased steam flow. Boron and control rods are used to maintain primary system temperature at the desired point. In order to decrease power, the operator throttles shut turbine inlet valves. This would result in less steam being drawn from the steam generators. This results in the primary loop increasing in temperature. The higher temperature causes the reactor to fission less and decrease in power. The operator could then add boric acid and/or insert control rods to decrease temperature to the desired point. Reactivity adjustment to maintain 100% power as the fuel is burned up in most commercial PWRs is normally achieved by varying the concentration of boric acid dissolved in the primary reactor coolant. Boron readily absorbs neutrons and increasing or decreasing its concentration in the reactor coolant will therefore affect the neutron activity correspondingly. An entire control system involving high pressure pumps (usually called the charging and letdown system) is required to remove water from the high pressure primary loop and re-inject the water back in with differing concentrations of boric acid. The reactor control rods, inserted through the reactor vessel head directly into the fuel bundles, are moved for the following reasons: * To start up the reactor. * To shut down the reactor. * To accommodate short term transients such as changes to load on the turbine. The control rods can also be used: * To compensate for nuclear poison inventory. * To compensate for nuclear fuel depletion. but these effects are more usually accommodated by altering the primary coolant boric acid concentration.

Fusion: smaller atoms are made into bigger atoms (2 Deuterium atoms -> 1 Helium atom) Fission: larger atoms are made into smaller atoms (1 Uranium 235 (Z=92) + 1 neutron -> 1 Krypton 92 (Z=36) + 1 Barium 141 (Z=56))

When a neutron is fired at a U235 atom, it splits the atom in two forming two very unstable forms of krypton and barium: Kr92 and Ba141. While this process is going on, which is called nuclear fission, enormous amounts of energy and three more neutrons are released. Then these three other neutrons hit more waiting U235 atoms, and this process repeats.

Uses:

This can be used for many things, it can be harnessed for energy, or packed into a bomb for warfare. No matter what it is being used for, we are still imagining the possibilities of nuclear fission.

A nuclear fission diagram typically shows a uranium or plutonium nucleus being bombarded by a neutron, splitting into two smaller nuclei, releasing additional neutrons and a significant amount of energy. The diagram helps illustrate the process of nuclear fission and its potential for generating power in a controlled manner in nuclear reactors.

You have a misapprehension there, it is uranium oxide that is used in fuel rods, not fossil fuel

Otto Hahn and Fritz Strassmann are credited with the discovery of nuclear fission in 1938. They observed that uranium atoms could be split into smaller nuclei by bombarding them with neutrons, releasing a considerable amount of energy.

The amount of energy released from a fission reaction is much greater than that from a chemical reaction because fission involves the splitting of atomic nuclei, leading to a significant release of nuclear binding energy. This energy release is millions of times greater than the energy released in chemical reactions, which involve breaking and forming chemical bonds.

An atom fission machine is typically referred to as a nuclear fission reactor. This device generates energy by splitting atoms, releasing a large amount of heat that is converted into electricity. It is commonly used in power plants to produce electricity on a large scale.

nuclear fission is where, i am going into a lot of detail here i found out in full extent a few days ago, you have U (uranium) 235 (isotope number) and it is floating around in the water around the reactor, the U235 now sucks up a thermal (same speed and temperature) neutron and Uranium explodes. Which releases 3 elements, heat, and 3 neutrons which all cause friction to heat up water. That water is usually 600ºF and is under about 2100lbs psi (pounds square inch) and that water heats up other water which turns turbines. It heats up other water so turbines and those items are not radioactive. Then that water is around 400ºF 900psi and is cooled off by other water under no pressure and that non-radioactive vapor forms clouds and stuff in the sky, the cooling tower near my house gives off 10,000 gallons of water a minute 80,000lbs. In the case of a "meltdown" the control room drops the control rods to suck up neutrons in water. If the Uranium is still causing heat they increase the boric acid % in the water. The acid sucks up neutrons right from uranium and gives no reaction. The tower, usually 2nd tallest on land, contains the reactor and normally can be hit by a Boeing 737 and only have a burn mark. 2.5ft concrete 3 inch steel and some lead.

Hope this answers your question =) I have more info about the Uranium and other things not mentioned.