Some Definitions 2
(7) Subchannel: For a PWR, BWR or LMFBR, the smallest flow area which is bounded by fuel
rods or a combination of fuel rods and a fuel assembly can or housing is called a subchannel. Several subchannels make up the flow area for a single fuel assembly.
(8) Structure: The geometry and integrity of the reactor core is maintained by structural elements such as support plates, spacer grids, or the metallic tubes used to clad the fuel in some reactor designs. The structural materials may also serve a dual role by moderating neutrons such as the graphite in an HTGR.
(9) Control elements: Absorbing material inserted into the reactor to control core multiplication. Although most commonly regarded as movable rods of absorber (control rods or blades), control elements may also consist of fixed absorbers or absorbing materials dissolved in the coolant. Common absorbing materials include boron, cadmium, gadolinium, and hafnium.
(10) Reactor core: The total array of fuel, moderator, and control elements.
(11) Reactor blanket: In a breeder or high conversion reactor the core is usually surrounded by a blanket of fertile material that more effectively utilizes the neutrons leaking out of the core.
For PWRs and BWRs, fuel blanket material may exist at the top and the bottom of the fuel rods within the fuel assembly.
(12) Reflector: A material characterized by a low absorption cross section used to surround the core in order to reflect or scatter leaking neutrons back into the core.
(13) Shielding: The reactor is an intense source of radiation. Not only must operating personnel and-the public be shielded from this radiation, but reactor components must as well be
protected. Hence absorbing material is introduced to attenuate neutron and gamma radiation. Radiation shielding is used to attenuate the emergent core radiation to levels that do not result in significant damage in reactor components. Cooling is usually required for such shields. Biological shielding reduces the radiation still further to acceptable levels for operating personnel.
(14) Support structure: The support plates that serve to maintain the core geometry.
(15) Reactor pressure vessel: The high pressure containment for reactor and associated primary coolant system.
rods or a combination of fuel rods and a fuel assembly can or housing is called a subchannel. Several subchannels make up the flow area for a single fuel assembly.
(8) Structure: The geometry and integrity of the reactor core is maintained by structural elements such as support plates, spacer grids, or the metallic tubes used to clad the fuel in some reactor designs. The structural materials may also serve a dual role by moderating neutrons such as the graphite in an HTGR.
(9) Control elements: Absorbing material inserted into the reactor to control core multiplication. Although most commonly regarded as movable rods of absorber (control rods or blades), control elements may also consist of fixed absorbers or absorbing materials dissolved in the coolant. Common absorbing materials include boron, cadmium, gadolinium, and hafnium.
(10) Reactor core: The total array of fuel, moderator, and control elements.
(11) Reactor blanket: In a breeder or high conversion reactor the core is usually surrounded by a blanket of fertile material that more effectively utilizes the neutrons leaking out of the core.
For PWRs and BWRs, fuel blanket material may exist at the top and the bottom of the fuel rods within the fuel assembly.
(12) Reflector: A material characterized by a low absorption cross section used to surround the core in order to reflect or scatter leaking neutrons back into the core.
(13) Shielding: The reactor is an intense source of radiation. Not only must operating personnel and-the public be shielded from this radiation, but reactor components must as well be
protected. Hence absorbing material is introduced to attenuate neutron and gamma radiation. Radiation shielding is used to attenuate the emergent core radiation to levels that do not result in significant damage in reactor components. Cooling is usually required for such shields. Biological shielding reduces the radiation still further to acceptable levels for operating personnel.
(14) Support structure: The support plates that serve to maintain the core geometry.
(15) Reactor pressure vessel: The high pressure containment for reactor and associated primary coolant system.
posted by Nuclear Engineer @ 12:03 AM
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