A control rod is a device that controls the power of a nuclear reactor. A reactor has several control rods. There are different types of rods, such as rods, plates, or tubes, made of neutron-absorbing substances such as aphnium, cadmium, graphite, or boron. These rods are inserted inside the core of a nuclear reactor.
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And can move in and out of nuclear reactors If the control rod is moved inside the reactor core Fission reactions are rare. Because the fuel rod will absorb a certain amount of neutrons. But if the control rod is moved away from the reactor core. Fission is more likely because there are more neutrons in the fission reaction. And if you want to turn off the nuclear reactor This is done by sliding all the control rods into the nuclear reactor core.
summarize
– Function of the joystick is to absorb neutrons. to stop the fission reduction reaction
– Substances used are boron, cadmium and hafnium.
– The joystick will move up and down. to reduce and increase the fission reaction
1) nuclear reactor core (reactor care)
the nuclear reactor core will be in the middle of the nuclear reactor. It is the region where the chain reaction occurs. Fuel bundles, control rods, neutron velocity fluids, and other supporting structures power a nuclear reactor. The reactor core is contained within the reactor tank.
2) Nuclear reactor
stainless steel High pressure resistance serves to contain the reactor core and cooling agent
3) Containment Vessel
It has a duty to prevent neutron radiation and gamma radiation caused by fission reactions. spread out from the nuclear reactor building Nuclear reactor shields are constructed of thick reinforced concrete. They are also often designed to withstand destruction in the event of a war.
Since the radiation source is from the fuel pellets, there are 4 layers of radiation blockers:
1) Fuel Cladding
2) Reactor Pressure Vessel
3) Containment Vessel
4) Nuclear Reactor Building
Nuclear reactors in Thailand
There is only one Thai nuclear reactor. Located at the Office of Atoms for Peace Ministry of Science and Technology, power size 2 MW (heat builder is General Atomics Company, USA wotpost
– nuclear power plant
nuclear power plant Refers to a power plant that uses nuclear fuel as a power source. Nuclear power plant is a type of thermal power with the same working principle as conventional thermal power plants. If the reader knows the operation of other thermal power plants, then you must understand the operation of nuclear power plants. Because thermal power plants and nuclear power plants are different sources of heat energy only. Other thermal power plants may run on coal, oil or natural gas. fuel But nuclear power plants use uranium-235 as fuel.
Types of Nuclear Power Plants
Nuclear power plants can be divided into three types:
1) High pressure water nuclear power plants
This type of power plant has two cooling water systems. The first system is a closed system. Therefore, the 1st cooling system is a high-pressure cooling system. so that the cooling water circulating in the system does not boil and does not turn into steam This system serves Directly cools the nuclear reactor core. Then there will be a cooling system, system 2, acting as a cooling system for the first cooling system. The nuclear fuel used in such power plants is uranium-235 with a concentration of about 2 to 3 %.
Advantages of this power plant is the water in the secondary cooling system as well as the steam that is used to turn the turbine. It is not exposed to any radioactive material, so such a power plant does not leak any radioactive material to the environment. But the disadvantage of this kind of power plant is that there is difficulty in operating the machine
2) Boiling water nuclear power plant
A nuclear power plant like this It’s not much different from a high-pressure water nuclear power plant. But this type of power plant has only one water cooling system. Therefore, the cooling water and steam are used to spin the turbine. There is contact with the fuel rods in the nuclear reactor core.
So this kind of power plant There is a chance of radioactive material leaking into the environment. The fuel used in such plants is uranium-235, with a concentration of about 2 to 3%, as is the case with high-pressure water nuclear power plants.
3) Heavy water nuclear power plants
CANDM stands for Canada Deuterium Uranium, developed by Canada using heavy water as both a coolant and retarder. The fuel used is Uranium-235 with a concentration of about 0.7%. The working principle is similar to a PWR power plant. There are 2 separate water cooling systems.
Since this type of electricity uses only 0.7% uranium-235 fuel, further uranium enrichment is not required.
1 gram of Uranium-235 gives heat equivalent to 3 tons of fine coal.
1 kg of coal produces 3 units of electricity.
1 kg of uranium produces 300,000 units of electricity.
Amount of electricity produced from 1 kg of various fuels
– 1 unit of firewood
– Coal 3 units
– 4 units of fuel oil
– Natural gas 6 units
– 50,000 units of natural uranium
– Uranium concentrate 3 – 4% 300,000 units
Advantages of nuclear power plants
1) It is a large power generation source with low cost of electricity generation
2) It is a clean power plant. It does not cause pollution and greenhouse gasses, helping to strengthen the stability of the power generation system.
3) Low fuel consumption stabilizing fuel supply
4) Fuel and fuel prices affect costs.
Small production has many fuel sources such as Canada and Australia. and the price does not fluctuate much compared to fossil fuels
limitations of nuclear power plants
1) High investment in construction
2) It is necessary to prepare the infrastructure and develop it.
3) Must have personnel with high knowledge and competence. in order to operate efficiently
4) Need preparation for handling radioactive waste and safety control measures to prevent accidents
5) is not acceptable to the public. People are concerned about their safety.
Top 10 largest nuclear power plants in the world
Untap 1, Kashiwazaki-Kariwa nuclear power plant, generating capacity of 8,212 megawatt hours Japan
2nd place: Uljin Nuclear Power Plant with a capacity of 6,157 megawatt hours South Korea
3rd place: Yonggwang Nuclear Power Plant, capacity of 6,187 megawatt hours South Korea
4th place Zaporizhia Nuclear Power Plant with a capacity of 6,000 megawatt hours, Ukraine
Untap 5, Grave Lines Nuclear Power Plant, generating capacity of 5,700 megawatt hours France
6th place: Paluel nuclear power plant with a capacity of 5,528 megawatt hours France
No. 7 Cattenom nuclear power plant with a capacity of 5,448 megawatt hours France
No. 8 Bruce Nuclear Power Plant, generating capacity of 5,090 megawatt hours, Canada
No. 9 Oil Capacity 4,710 megawatt hours Japan
No. 10 Fukushima Daiichi nuclear power plant with a capacity of 4,696 megawatt hours Japan