What do pressurized water reactors do

As the fuel is "burned" in the reactor, its density gradually increases, resulting in small voids to develop inside the fuel tube. These void spaces can cause a problem because high pressures could cause stress to the tubes, increasing the likelihood of a rupture.

To avoid this problem, the tubes are pressurized with helium at about 3. As fission gas products accumulate over the fuel's lifetime, the pressure gradually balances with the high pressure of the core.

As mentioned before, light water is used as the coolant and moderator for a pressurized water reactor. Light water is much more abundant than heavy water, as it makes up Light water does not make as good of a moderator as heavy water or graphite as a result of its relatively high absorption of neutrons. However, its use as a moderator makes for an important safety feature; if there is a loss of coolant accident LOCA , there will also be a loss of moderator causing the nuclear chain reaction to stop.

Also if the moderating water overheats and becomes steam inside the bottom reactor core, there will be less moderator and therefore the chain reaction will stop. As the name implies, the water in the reactor is pressurized.

This is due to the fact that as the pressure gets higher, the boiling point of water increases with it. This stem is pushed to the main turbine generator, and powering it and further creating electricity. Any unused steam is condensed into water and pumped out of the condenser, reheated and then pumped back into the steam generator where the cycle begins again. Pressurized water reactors have advantages over the other light water reactors and earlier generation nuclear sites.

Since the primary and secondary loops are separate, water can never be contaminated by radioactive material in the main system loop. Pipes then feed the steam directly to a turbine to produce electricity. Nuclear reactors are the heart of a nuclear power plant. Nuclear Fission Creates Heat The main job of a reactor is to house and control nuclear fission —a process where atoms split and release energy.

Fission and Fusion: What is the Difference? There are two types of light-water reactors operating in America. Pressurized water reactors. Graphic by Sarah Harman U. Department of Energy. These tubes are surrounded by another water system called the secondary or steam generating system. The heat, but not the water, from the primary coolant is transferred to the secondary, system which then, turns into steam.

The primary and secondary systems are closed systems. This means the water flowing through the reactor remains separate and does not mix with water from the other systems. The steam is pumped from the containment building into the turbine building to push the giant blades of the turbine.

The turbine is connected to an electrical generator. After turning the turbines, the steam is cooled by passing it over tubes carrying a third water system called the condenser coolant.