'Super Steel' Sought For Fusion Reactors

Smivs writes "New research shows how steel will fail at high temperatures because of the magnetic properties of the metal. Scientists say an understanding of how the Twin Towers collapsed will help them develop the materials needed to build fusion reactors. The New York buildings fell when their steel backbones lost strength in the fires that followed the plane impacts. Dr Sergei Dudarev told the British Association Science Festival that improved steels were now being sought. The principal scientist at the United Kingdom Atomic Energy Authority (UKAEA) said one of the first applications for these better performing metals would be in the wall linings of fusion reactors."

Comments

Re:If it doesn't work...

[MyLongNickName]

Popular Mechanics explains this. Not that I think it will matter to the conspiracy crowd.

Re:Current record holder

[BlueParrot]

What you say is largely true, but for nuclear applications you usually have a few more constraints that make steel look more attractive again.

The core of a fast breeder reactor, or the structural components of a fusion reactor, will unavoidably be exposed to a very intense flux of high energy neutrons. These neutrons can cause all kinds of defects in the material you use, ranging from dislocating atoms to changing their elements due to nuclear transmutations, and whatever material you use must be able to withstand the irradiation. Many nickel alloys fail for this reason.

Also any material which absorbs a lot of neutrons, or reduces their energy, is going to cause issues. If you use Nitrogen in a ceramic it may need to be enriched to prevent excessive Carbon-14 production as an example. Some elements, like Lithium, Cobalt and Bismuth, produce very troublesome radioactive isotopes when irradiated. Carbon is quite good, and carbon based ceramics are heavily researched, but it is a rather light nucleus, and will slow neutrons that scatter against it. This may be desirable in a thermal reactor, but for fusion reactors and fast breeder reactors you want a very high neutron energy to enable the destruction of long lived waste isotopes, and this means you need to limit the amount of carbon present in your core and structural materials.

Furthermore materials to be used for a reactor need to go through very time consuming and thorough testing program , and this is why steels are very attractive candidates since much of the necessary data already exists. Sure, using something like Silicon Carbide may be worth investigating ( and it is indeed being investigated for a number or reactor designs ) , but even thou it has good thermal conductivity, corrosion resistance and thermal stability, it is not immediately clear that it will withstand the radiation environment, it's fracture hardness is less than ideal, and you need to be able to reliably produce it to the strict standards required by the nuclear industry. To develop and test a material for nuclear applications is a very expensive procedure, so if you can use materials that you already have data for, it will dramatically reduce the necessary research and development costs.

Also, as usual there is a cost issue of the material itself. Tungsten, with its high melting point, good strength at elevated temperatures, and low neutron absorption is very attractive from technological aspects, but building an entire reactor from it will hurt your bank account.