1. Coolant materials: Common liquid coolant materials include water, heavy water and liquid metals - sodium, sodium-potassium alloy, bismuth, lead-bismuth alloy, etc. Common gas coolant materials include carbon dioxide (CO2), air and helium (He).
2. Moderating materials: Commonly used moderating materials include solid and liquid. Solid moderating materials include graphite, beryllium and beryllium oxide. Commonly used liquid moderating materials include light water and heavy water, as well as organic moderating materials.
3. Structural materials: Reactor structural materials include core structural materials, fuel (rod) cladding materials, reactor pressure vessels, driving mechanism materials, etc.
4. Control materials: Such materials include hafnium, silver-indium-cadmium alloys, boron-containing materials and samarium, erbium, europium, gadolinium and some of their oxides and carbides in rare earth materials .
5. Shielding materials: Materials used in facilities to prevent workers and equipment from radiation damage. They mainly include lead, iron, heavy concrete, water and other materials.
Extended information
Classification of nuclear fuel:
1. Metal fuel: Uranium is a commonly used nuclear fuel. Natural uranium contains only 0.7% U235, and the rest is U238. Generally, enriched uranium with a U content greater than 0.7% is used. This can be obtained by gas diffusion or centrifugation.
2. Ceramic fuel: including oxides, carbides and nitrides of uranium, plutonium, etc. Among them, UO2 is the most commonly used ceramic fuel. UO2 has a very high melting point (2865°C) and good high-temperature stability. During irradiation, a large amount of fission gas can be retained in the UO2 fuel pellet.
3. Fluid fuel: In a homogeneous reactor, nuclear fuel is suspended or dissolved in water, liquid metal or molten salt, thereby becoming fluid fuel (liquid fuel).
Baidu Encyclopedia-Nuclear Materials