The functions of the Pressurized Water Reactor are:
Diagram and Flow Path
|The figure to the left illustrates the reactor vessel. The green and
orange colored core barrel sits within the reactor vessel. Water enters from the cold leg
nozzles, flows downward in the space between the core barrel and the reactor vessel, then
flows upward through holes in the bottom support plate on which the fuel assemblies stand.
The water flows along the fuel assembly, out the top support plate, then into the upper
plenum of the reactor. From there, the water flows out one of the hot leg nozzles.
The protrusions on top hemispherical head of the reactor are the control rod drive mechanisms (CRDMs) and position indicating devices. The actual control rods are inside of the reactor and stick partway into the top of the fuel assembly. If the reactor protection system actuates, the power is cut off to control rod drive mechanisms and the CRDMs drop by gravity into the reactor. Testing after each refueling verifies that the rods will insert within a design time period (about 2-3 seconds).
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|Courtesy Westinghouse Electric Corp.|
Joseph Gonyeau. Copyright © 1996 Cannon Valley Web-Lynx. All rights reserved. Revised: November 15, 1996