The Man-Made Sun Exploration -- Tungsten Material Upgrading Plan
- Details
- Category: Tungsten Information
- Published on Monday, 02 October 2017 00:03
As people's demand for energy continues to grow rapidly, conventional energy such as oil and fuel, are about to dry up in the foreseeable future.
The fusion energy produced by light nuclear fusion reaction is an important way to solve the energy problem of human beings. The ITER ITER device is a test project for human exploration of nuclear fusion power generation. The international thermonuclear fusion experimental reactor ITER device is an experimental project for the generation of nuclear fusion power. At present, the world has the European Union, China, the United States, Japan, South Korea, Russia and India 7 Parties participated in the project. China and the European Union have leading progress. China's nuclear fusion device is called EAST, the eastern super ring.
Tungsten plays an important role in ITER. Tungsten and tungsten alloys have excellent properties such as high melting point, high thermal conductivity, high density, low thermal expansion coefficient, low vapor pressure, low tritium retention, low sputtering yield and high self sputtering threshold, so they are considered by IAEA as the most promising plasma facing wall material in the future, and the tungsten divertor is one of the key components of ITER.
However, there are still many problems in the application of tungsten in nuclear fusion devices, such as ductile brittle transition temperature is high (about 400°C), Recrystallization temperature is low (about 1400°C), irradiation hardening and embrittlement etc. The properties are characterized by low temperature brittleness, recrystallization brittleness and irradiation brittleness.
In order to improve the defects of tungsten in China, scholars have done a lot of test drive levigation, three schemes are proposed to solve the problems. They are nanometer tungsten powder , synthetic tungsten based alloycarbide alloy and doped rare earth.
Scientists have found that, although tungsten is considered the most promising facing plasma wall material in fusion device. However, the major products of nuclear reaction, He and neutron irradiation, can cause damage to tungsten, ultrafine grain and nanocrystalline tungsten have more grain boundaries and resist higher He radiation. The smaller the grain size is, the shorter the diffusion path of He particles to trap and the radiation damage can be greatly reduced.
Secondly, due to high ductile brittle transition temperature (DBTT), tungsten is easy to produce a strong thermal stress in the plasma during the operation, a more effective method is to let other tungsten and other plastic good, difficult to melt, low activation metal alloying. The scholars found that tantalum has good plasticity, low activation, high radiation resistance, and transformation to tungsten under high energy neutron irradiation, thus preventing the formation of brittle phase. Adding a small amount of metal Ta to the tungsten matrix can obviously improve the plasticity of the tungsten matrix composites. W - Ta alloy in the future hopefully become the divertor tungsten alloy material.
Dispersion of tungsten is not strong, after calcination researchers found out that, TiC has a high melting point, low density, and similar thermal expansion coefficient with tungsten, and it can form nano tungsten and (Ti, W) C solid solution, it is an effective reinforcement materials of tungsten alloy. The experimental results show that the hole density of W-TiC irradiated by neutron irradiated tungsten and titanium dioxide is obviously less than that of pure tungsten. Compared with other strengthening phases, the irradiation hardening resistance of ultrafine W-TiC is stronger.
Through these schemes, scientists have improved some problems with tungsten materials. However, science also believes that the existing materials are difficult to meet the severe conditions of high temperature, high pressure and intense neutron irradiation in the future fusion reactors. Tungsten and tungsten alloys, due to their excellent properties, are considered to be the most promising facing plasma first wall materials for nuclear fusion devices in the future. But it also need to have a high improvement in order to fully meet the requirements of future nuclear fusion equipment for commercial applications, it is also an important challenge and task to find and develop new materials for anti radiation damage tungsten materials for future nuclear fusion devices.
- Tungsten Manufacturer & Supplier, Chinatungsten Online: www.chinatungsten.com
- Tungsten News & Prices of China Tungsten Industry Association: www.ctia.com.cn
- Molybdenum News & Price: news.molybdenum.com.cn
- Tel.: 86 592 5129696; Fax: 86 592 5129797; Email: sales@chinatungsten.com
sales@chinatungsten.com
闽公网安备 35020602000140号