PV Gap

Nelson Said:

What does Nuclear (Uranium) energy do?

We Answered:

Electricity and steam heat, irradiate gems, produce medical isotopes and tritium. Non uranium nuclear energy is used to sterilize things, irradiate food, radiography, medical diagnosis, medical treatment, and many other uses.
Despite all the cosmic energy that the word "nuclear" invokes, power plants that depend on atomic energy don't operate that differently from a typical coal-burning power plant. Both heat water into pressurized steam, which drives a turbine generator. The key difference between the two plants is the method of heating the water. While coal plants burn fossil fuels, nuclear plants depend on the heat that occurs during nuclear fission, when one atom splits into two.
There are several components common to most types of reactors:

Fuel. Usually ceramic pellets of uranium oxide (UO2) arranged in Zirconium steel alloy tubes to form fuel rods. The rods are arranged into fuel assemblies in the reactor core.

Moderator. This is material which slows down the neutrons released from fission so that they cause more fission. It is usually water, but may be heavy water or graphite.

Control rods. These are made with neutron-absorbing material such as silver, cadmium, hafnium or boron, and are inserted or withdrawn from the core to control the rate of reaction, or to halt it. (Secondary shutdown systems involve adding other neutron absorbers, usually boron in the primary cooling system.) This controls the average temperature and allows extra fuel to be added for a extended time between refueling.

Coolant. A liquid or gas circulating through the core so as to transfer the heat from it. In light water reactors the moderator functions also as coolant.

Pressure vessel or pressure tubes. Usually a robust steel vessel containing the reactor core and moderator/coolant, but it may be a series of tubes holding the fuel and conveying the coolant through the moderator.

Steam generator. Part of the cooling system in Pressurized Water Reactors where the heat from the reactor is used to make steam for the turbine. Some reactor designs, called Boiling Water Reactors, do not have S/Gs but instead allow boiling in the reactor core to produce steam for the turbine..

Containment. The structure around the reactor core which is designed to protect it from outside intrusion and to protect those outside from the effects of radiation in case of any major malfunction inside. It is typically a meter (3ft.) thick concrete and steel structure designed to be air/water tight to prevent any leak to the environment in the worst case Loss Of Coolant accident.

Most reactors need to be shut down for refueling, so that the pressure vessel can be opened up. In this case refueling is at intervals of 1-2 years, when a quarter to a third of the fuel assemblies are replaced with fresh ones. The CANDU and RBMK types have pressure tubes (rather than a pressure vessel enclosing the reactor core) and can be refueled while still generating electricity by disconnecting individual pressure tubes.

If graphite or heavy water is used as moderator, it is possible to run a power reactor on natural instead of enriched uranium. Natural uranium has the same elemental composition as when it was mined (0.7% U-235, over 99.2% U-238), enriched uranium has had the proportion of the fissile isotope (U-235) increased by a process called enrichment, commonly to 3.5 - 5.0%. In this case the moderator can be ordinary water, and such reactors are collectively called light water reactors. Because the light water absorbs neutrons as well as slowing them, it is less efficient as a moderator than heavy water or graphite.

Practically all fuel is ceramic uranium oxide (UO2 with a melting point of 2800°C) and most is enriched. The fuel pellets (usually about 1 cm diameter and 1.5 cm long) are typically arranged in a long zirconium alloy (zircaloy) tube to form a fuel rod, the zirconium being hard, corrosion-resistant and permeable to neutrons. Up to 264 rods form a fuel assembly, which is an open lattice and can be lifted into and out of the reactor core. In the most common reactors these are about 3.5-4.0 meters (12ft.) long.
The uranium 235 in these pellets absorb slowed down (moderated or thermal) neutrons, becoming unstable U-236 which splits, creating; heat, gamma, neutrons, and fission fragments. The heat generated can be calculated from the mass loss in the fission process equal to the famous equation E=MC squared, also known as binding energy. The energy released from a single fuel pellet is equivalent to the energy released burning 1 ton of coal.
The links below have some excellent detailed information and graphics about nuclear power. I hope this helps you to de-mystify nuclear power, it really isn't that complicated, and is a safe, reliable, environmentally friendly, economical, energy source.