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Control rods are usually used in control rod assemblies (typically 20 rods for a commercial PWR assembly) and inserted into guide tubes within the fuel elements. Control rods often stand vertically within the core. In PWRs they are inserted from above, with the control rod drive mechanisms mounted on the reactor pressure vessel head. In BWRs ...
The term static differentiates it from DRAM, which must be periodically refreshed. sound card. Also audio card. An internal expansion card that facilitates economical input and output of audio signals to and from a computer under control of computer programs. storage device synchronous dynamic random-access memory (SDRAM)
PC—Personal Computer; PCB—Printed Circuit Board; PCB—Process Control Block; PC DOS—Personal Computer Disc Operating System; PCI—Peripheral Component Interconnect; PCIe—PCI Express; PCI-X—PCI Extended; PCL—Printer Command Language; PCMCIA—Personal Computer Memory Card International Association; PCM—Pulse-Code Modulation
Control rods are a series of rods that can be quickly inserted into the reactor core to absorb neutrons and rapidly terminate the nuclear reaction. [2] They are typically composed of actinides, lanthanides, transition metals, and boron, [3] in various alloys with structural backing such as steel. In addition to being neutron absorbent, the ...
In light-water reactors, this is achieved by inserting neutron-absorbing control rods into the core, although the mechanism by which rods are inserted depends on the type of reactor. In pressurized water reactors the control rods are held above a reactor's core by electric motors against both their own weight and a powerful spring. A scram is ...
A control rod channel filled with graphite absorbs fewer neutrons than when filled with water, so the difference between inserted and retracted control rod is increased. When the control rod is fully retracted, the graphite displacer is located in the middle of the core height, with 1.25 m of water at each of its ends.
The control unit (CU) is a component of a computer's central processing unit (CPU) that directs the operation of the processor. A CU typically uses a binary decoder to convert coded instructions into timing and control signals that direct the operation of the other units (memory, arithmetic logic unit and input and output devices, etc.).
Some reactor poisons are deliberately inserted into fission reactor cores to control the reaction; boron or cadmium control rods are the best example. Many reactor poisons are produced by the fission process itself, and buildup of neutron-absorbing fission products affects both the fuel economics and the controllability of nuclear reactors.