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How are uranium dioxide fuel pellets arranged inside a light-water reactor?

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Labeled diagram showing the process of a nuclear power plant with a pressurized-water reactor. Water circulates through the reactor core, heats to produce steam in a steam generator, which drives a turbine connected to an electric generator. Steam is then cooled in a condenser using water from a cooling tower, which releases nonradioactive water vapor. Control rods, pumps, and transmission lines are also indicated. — nuclear power Schematic diagram of a nuclear power plant using a pressurized-water reactor.

In a light-water reactor (LWR), uranium dioxide is processed into dense, sintered ceramic pellets. These pellets are loaded into cladding tubes made of a zirconium alloy, which are then filled with an inert gas and welded shut to form fuel rods or pins.12

To create a fuel assembly, these rods are bundled together in a square lattice arrangement. Proper spacing between the rods is maintained by top and bottom manifolds, through which the ends of the pins pass, as well as by spacer grids distributed along the middle portion of the pins. These completed assemblies are then loaded into the reactor core.213