Select All. Close Proceed. Export to Mendeley. Get permanent URL for this record. Please provide a name for this query:. Saved to Workspace! Close Go to Workspace. Email Results. Email URL only? Number of results:. 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.
As the steam is cooled, it condenses back into water and is returned to the steam generator to be used again and again. This steam and water mixture rises to the top of the reactor and passes through two stages of moisture separation. Water droplets are then removed and steam is allowed to enter the steam line. The steam is directed to the turbine. However, the walls do not need to be as thick as in PWRs, so the costs are essentially the same.
Since the BWR has only one primary loop, as mentioned earlier, the very water that flows through the reactor core is the same one used to spin the turbines. In contrast, pressurized water reactors do not convert the hot water in the core to steam, therefore, two loops are necessary. Less water needs to flow through a BWR than through a PWR, however, there are complications because the water becomes radioactive in its circulation.
This means that there must be extra shielding in the non-reactor parts of the power plant. Control rods are placed in the bottom of the reactor, rather than the top as in PWRs.
This is because in a boiling water reactor there is more steam at the top visible in Figure 4 below , and placement of control rods in the steam portion would have a lesser effect than their placement in the water portion of the reactor.
Seen below is the flow of water through a boiling water reactor power plant, and its production of electricity. Fossil Fuels. Nuclear Fuels. Here steam is generated within the reactor itself.
Here the water in the primary loop is maintained at high pressure 15 — 17 MPa to avoid boiling at reactor exit. Here water pressure remains comparatively low 7 — 8 MPa as it is allowed to boil. A pressurizer is required to use mandatorily to maintain water pressure in such a way that it does not evaporate even at very high temperature. No such pressurizer is employed as evaporation of the water is desired.
PWR has comparatively low thermal efficiency owing to two different loops. BWR offers higher thermal efficiency. In PWR, the control rods are inserted from the top of the nuclear reactor. In BWR, the control rods are inserted from the bottom of the nuclear reactor. Since the fluid is maintained at high pressure, so the PWR core volume is less. For the same power generation, core volume of the BWR is comparatively larger. Since the working fluid loop is separated from the primary loop, so PWR is less risky in spreading of radioactive materials owing to leakage.
Since same fluid passes through the reactor and turbine in BWR plants, so any leakage in the turbine can spread radioactive elements into the atmosphere.
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