-
Anonymous users2024-02-10reflective layer in the guide tube.
Because it is difficult to set the control rod guide tube in the core, the control rod is difficult to insert, and the control rod is usually inserted in the guide tube arranged in the reflective layer. Although the column bed can be equipped with a control rod guide pipe in the core, the control rod is usually set in the reflective layer due to the high temperature of the core and the harsh working environment of the control rod, which is used for reactive control and reactor power regulation during normal operation, and can also be used for emergency shutdown for small reactors.
For large reactors where the reflective layer control rod does not provide sufficient slot margin, a core control rod should be installed as a safety rod for core insertion during long-term shutdown.
-
Anonymous users2024-02-09High-temperature gas-cooled reactors are developed on the basis of low-temperature gas-cooled reactors with natural uranium as fuel, graphite as moderator, and CO2 as coolant. The cryogenic gas-cooled reactor is one of the earliest reactor types in the development of reactors in the world, which was used to produce plutonium in the early days, and began to become a commercial power reactor for power generation after the mid-50s. The development of gas-cooled reactors can be broadly divided into four phases:
Early gas-cooled reactors, improved gas-cooled reactors, high-temperature gas-cooled reactors, and modular high-temperature gas-cooled reactors.
Early gas-cooled reactors (magnox).
In 1956, the 50 MW Calder Hall gas-cooled reactor was built in the United Kingdom, marking the commercialization of this reactor type. This kind of gas-cooled reactor uses graphite as the moderator, CO2 gas as the coolant, natural uranium metal as the fuel, and Magnox alloy as the cladding material for the fuel rods, so this kind of reactor is also called the Magnox gas-cooled reactor. By the early 70s, 36 Magnesium Knox reactors had been built and operated in Britain, France, Italy, Japan and Spain, with a capacity of 8 200 MW.
This reactor type is in good condition and has high availability, which has played a great role in the early entry of nuclear energy into the commercial market.
Improved Gas-Cooled Reactor (AGR).
In order to improve the thermal performance of the reactor, the United Kingdom has developed an improved gas-cooled reactor (AGR), the reactor still uses graphite as a moderator and CO2 gas as a coolant, but stainless steel is used instead of magnesium nox alloy as the cladding material for fuel, and the outlet temperature of CO2 is increased from about 400 to 670 after the improvement. A prototype reactor with an electric power of 32 MW was built in Windskel, UK, in 1963, and from 1976 to 1988, a total of 14 improved gas-cooled reactors were in operation with a total electrical power of 8 890 MW.
High-temperature gas-cooled reactors (HTGR).
The use of chemically inert helium with good thermal properties as the coolant, the all-ceramic coated particles as the fuel element, and the use of high-temperature resistant graphite as the moderator and core structural material, so that the helium temperature at the outlet of the core reaches 950 or even higher, which can not only be used for power generation, but also has a wide range of application prospects in high-temperature process heat.
Modular High Temperature Gas-Cooled Reactor (MHTGR).
Modular high-temperature gas-cooled reactor is characterized by miniaturization and inherent safety characteristics, which technically ensures that the reactor can be safely shut down in any accident situation, even in the case of coolant loss, the waste heat of the core can be exported from the reactor by natural convection, heat conduction and radiation, so that the core temperature rises slowly, and the maximum temperature of the fuel element is limited to the allowable temperature below 1 600; Economically, it can compete with other reactor-type nuclear power plants with the advantages of modular combination, standardized production, short construction time, and low investment risk.
The dry sprinkle fermentation bed seems to have a national patent, which seems to be better.
Inverted bucket traps and free float® traps are both mechanical traps. They work on the basis of the density difference between condensate and steam, have a relatively small degree of supercooling, and are suitable for hydrophobicity of heating equipment in production processes. >>>More
The advantages of fluidized bed dryer mainly include:
High efficiency: The fluidized bed dryer adopts fluidized drying technology, which makes the material in a moving state through high-speed vibration and air flow, so as to make the contact between the material and the drying medium more sufficient, and improve the drying efficiency. >>>More
Now most of the school football is used this kind of dribbling often to dodge and block the opponent, most of the origins are more violent, it doesn't look like playing, the same as wrestling, so playing rugby often breaks hands and feet, so use the hand to block instead of throwing the opponent out, which can reduce the damage, and relative to the short stature of people to make up for the gap between strength, but also more balanced, American high schools also mostly adopt this way of playing, but still retain the original style.
Aggression is defense, as the name suggests, aggression When defending a player with a ball, when his ball is exposed, immediately reach out to copy, but when he wants to break through, use his body against him and prevent him from entering the three-second zone, but when he holds the ball again, he is dribbling is a second dribble, you have to go up and use your body to cling to him, and block all passing routes, and at the same time reach out to copy the ball, giving him the feeling of sticking to his body, Zhenyang's defensive method has a high ball break rate (hands-on practice)!! When defending a player who is not looking for a player, he goes to **you follow**, and when his teammates want to pass the ball to him, you have to squeeze him tightly, (that is, around the front defense) speed is important at this point! In this way, force his teammates to make a mistake in passing, and then let him (your defender) miss the ball, and immediately dodge and grab the ball!