Lättvattentekniken

Lättvattentekniken, which translates to "light water technology," is a term that generally refers to nuclear reactor designs that utilize ordinary water as both a coolant and a neutron moderator. This is in contrast to heavy water reactors, which use heavy water (deuterium oxide) for these purposes. Light water reactors are the most common type of nuclear reactor in operation worldwide.

The two primary types of light water reactors are the Pressurized Water Reactor (PWR) and the Boiling Water Reactor (BWR). In a PWR, the water in the primary loop is kept under high pressure to prevent it from boiling. This hot, pressurized water then flows through a steam generator, where it transfers heat to a secondary loop of water, producing steam. This steam drives a turbine connected to an electric generator. In a BWR, the water is allowed to boil directly within the reactor core. The steam produced rises and is used to drive the turbine directly.

Light water reactors require enriched uranium fuel, typically with a concentration of 3-5% uranium-235, because ordinary water is less efficient at moderating neutrons compared to heavy water. Despite this, the abundance and low cost of ordinary water, along with the established technological base, have made light water reactors the dominant choice for civilian nuclear power generation. They are known for their operational stability and relatively straightforward design compared to some other reactor types.