Metals and Alloys for Nuclear Energy
Metals and alloys for nuclear energy
There are two important ways in the making of nuclear energy: nuclear fission and nuclear fusion. Fusion and fission have a different working mechanisms, thus other materials are used. In a nuclear reactor fuel rods are bombarded with neutrons causing fission of the fuel. This way energy is released. With this energy water is heated to steam and with the use of heat exchangers and steam turbines electricity is generated. As fuel is usually uranium used, but also plutonium and thorium are possible energy sources. To protect the environment from radioactivity, the fuel is cladded. For the cladding is usually zirconium alloys or stainless steels used because it should be able to let the neutrons pass and be corrosion resistant. This cladding has also the advantage to give strength to the rod. The reaction in the nuclear reactor is controlled with control rods. These control rods should be able to absorb the neutrons, so cadmium and boron are most of the time used. This reaction takes place in a stainless steel pressure vessel. Nuclear fusion takes typically place in a tokamak. This is a toroidal chamber with magnetic coils. In this chamber fusion takes place under the form of plasma. A lot of energy is released. The vacuum vessel is made of stainless steel that is constantly cooled because the plasma is very hot. The magnetic coils are made of niobium-tin superconductors causing a magnetic field to keep the plasma away from the walls of the vacuum vessel.
Astrid Standaert
1
Nuclear fission
Introduction
One of the most common reactions in nuclear fission is the attack of an 235U atom by a neutron. The result of this collision is that the uranium splits in 91Kr, 142Ba and 3 neutrons and energy is released, see Figure 1.
Figure 1: Typical nuclear fission reaction
Other reaction products are also possible. These energy is then used to heat up water. This hot water or steam (depending on the type of nuclear reactor)
There are two important ways in the making of nuclear energy: nuclear fission and nuclear fusion. Fusion and fission have a different working mechanisms, thus other materials are used. In a nuclear reactor fuel rods are bombarded with neutrons causing fission of the fuel. This way energy is released. With this energy water is heated to steam and with the use of heat exchangers and steam turbines electricity is generated. As fuel is usually uranium used, but also plutonium and thorium are possible energy sources. To protect the environment from radioactivity, the fuel is cladded. For the cladding is usually zirconium alloys or stainless steels used because it should be able to let the neutrons pass and be corrosion resistant. This cladding has also the advantage to give strength to the rod. The reaction in the nuclear reactor is controlled with control rods. These control rods should be able to absorb the neutrons, so cadmium and boron are most of the time used. This reaction takes place in a stainless steel pressure vessel. Nuclear fusion takes typically place in a tokamak. This is a toroidal chamber with magnetic coils. In this chamber fusion takes place under the form of plasma. A lot of energy is released. The vacuum vessel is made of stainless steel that is constantly cooled because the plasma is very hot. The magnetic coils are made of niobium-tin superconductors causing a magnetic field to keep the plasma away from the walls of the vacuum vessel.
Astrid Standaert
1
Nuclear fission
Introduction
One of the most common reactions in nuclear fission is the attack of an 235U atom by a neutron. The result of this collision is that the uranium splits in 91Kr, 142Ba and 3 neutrons and energy is released, see Figure 1.
Figure 1: Typical nuclear fission reaction
Other reaction products are also possible. These energy is then used to heat up water. This hot water or steam (depending on the type of nuclear reactor)
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