Uranium-235
A fuel rod is a long, slender tube that contains the fuel pellets (usually uranium or plutonium) used in a nuclear reactor. These fuel rods generate heat through nuclear fission reactions, which is then used to produce electricity. Multiple fuel rods are assembled together in a fuel assembly to power the reactor.
The nuclear fuel is typically contained in the reactor core, which is a central part of the nuclear reactor where the fission reaction takes place. The fuel rods, which contain the nuclear fuel pellets, are inserted into the reactor core during operation.
Control rods in a nuclear reactor are typically made of materials such as boron, cadmium, or hafnium. These materials are selected for their ability to absorb neutrons and regulate the reactor's power levels by controlling the rate of nuclear reactions.
Fuel rods in nuclear plants are typically made of zirconium alloy tubes filled with uranium dioxide pellets. The zirconium alloy provides structural support and heat transfer capabilities, while the uranium dioxide serves as the fuel source for the nuclear reaction.
Boric acid solution is used to bathe the control rods and fuel bundles of a nuclear reactor. This solution helps control the nuclear reaction by absorbing excess neutrons.
For the PWR, the reactor core which is an array of fuel assemblies, inside a very strong pressure vessel made of thick steel. The top of the vessel is removable for fuelling, and also holds the control rods and their mechanisms. The whole thing is enclosed in a secondary containment. Also inside this is the primary circuit which circulates water through the core to carry away the heat produced by the fuel assemblies, and the secondary circuit steam raising units which send steam to the turbine. See link below
Nuclear fission takes place in the nuclear fuel rods that are placed in the reactor core that is situated in the reactor pressure vessel. The reactor pressure vessel is usually situated inside the reactor containment.
The reactor vessel is the main container that houses the nuclear fuel, control rods, and coolant in a nuclear reactor. Its purpose is to contain and shield the nuclear reactions happening inside, and to provide structural support and safety for the reactor core.
fuel rods and control rods
Fuel rods are used to hold pellets of uranium in nuclear reactors. These rods are typically made of a material like zirconium to encase the uranium pellets and control the nuclear fission reactions within the reactor.
The fuel in a nuclear reactor is located in the fuel rods, which are typically made of materials such as enriched uranium or plutonium. These fuel rods are where the nuclear fission reaction takes place, producing heat that is used to generate electricity.
The fission happens in the fuel, which is usually in fuel rods inside the reactor. The rods are spaced at a particular distance apart and fill the reactor.
The number of fuel pins in a reactor will vary depending on its design and objectives. In one reactor that I worked with, I seem to recall 137 fuel assemblies, with four bundles each, with 62 fuel pins each. That translates to 33,976 fuel pins in the reactor, each about 12 feet long.
Making the base of a reactor vessel out of a neutron absorbing material like the control rods are made out of (like boron) would have little effect on a meltdown. The primary source of heat in a meltdown is the radioactive decay of fission fragments. This decay heat cannot be stopped by anything. It can only be carried away by a coolant of some kind. If a meltdown is severe, the molten fuel and cladding will pool on the bottom of the reactor vessel and melt through it. This will be true in a gross meltdown regardless of the material from which the reactor vessel bottom is made.
for pressurized light water reactor type, as an example, the nuclear reactor components are * Reactor vessel (that contains the nuclear fuel and surrounded with water and contains control rod for power control and for safety) * reactor coolant pump * steam generator * reactor pressurizer * piping out of the vessel to the pressurizer, from pressurizer to steam generator, from steam generator to reactor coolant pump, and from pump back to the reactor vessel.
Uranium is the fuel... moderators can be water... control rods are various substances to absorb extra neutrons some use carbon. Steel (iron) is what the reactor vessel is made of.
The nuclear fuel is found in the fuel rods. These fuel rods are formed into fuel bundles called fuel assemblies, and together they make up the reactor core.