Slashdot Mirror
'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."
Popular Mechanics explains this. Not that I think it will matter to the conspiracy crowd.
See my journal for slashdot ID's by year. Mine created in 2005. http://slashdot.org/journal/289875/slashdot-ids-by-year
Yeah. The Twin Towers should have toppled over, but instead, they blew up like a building that was being imploded for demolition.
It figures that today of all days would bring out the conspiracy theories. So you're saying that a building weighing probably millions of tons could topple over a specific and single pivot point?
Also, the melting point of the steel used in the Twin Towers is actually about 400 degrees HOTTER than the temperature at which jet fuel burns.
If the jet fuel is out in the open, where heat can dissipate, that would be true. But this was a whole LOT of fuel in an enclosed space, so as the fuel burnt, the steel could keep getting hotter and hotter. Burning fuel = energy released. If the energy cant escape, it builds up in the form of heat.
The Twin Towers would also be the first example in history of a steel building where the steel failed due to fire.
And the thousands of tons that slammed into it at high velocity had nothing to do with it? (Actually, I'm guessing that had something to do with it, but not sure.) If you're spinning theories here, you need to stick to WTC building 7, the collapse of which was thoroughly studied, and concluded that fire alone was the result of it's collapse.
$7.95/mo, 200 GB disk, 2TBxfer, MySQL, PHP, RoR.
And the thousands of tons that slammed into it at high velocity had nothing to do with it?
NOVA recently did a special about this. Apparently the NIST investigation concluded that the impact of the jets stripped away a lot of the fire-proofing material that should have protected the steel.
Once the steel was exposed to all that heat it was only a matter of time before it failed. It never melted either -- it became flexible and eventually failed as a result.
I want peace on earth and goodwill toward man.
We are the United States Government! We don't do that sort of thing.
The point of this article eludes me.
You aren't the only one. If you want something that can retain it's strength at high temperatures, don't use steel. I recommend some sort of engineered ceramic, like tungsten carbide (which I believe is what you meant).
The article seems to ignore the fact that engineers see steel becoming weaker with heat as a benefit. If steel was always super strong at any temperature, how would you make anything out of it? Engineers currently utilize the "irregularities" (we call them dislocations) in steel to manufacture things. One such process is known as work hardening. When certain materials, like steel, are formed (bent, rolled, etc.) at low temperature, the dislocations propagate and move. The dislocations interact with each other, like tangling up a ball of yarn, making the material stronger. The component can then be heated to make further manufacturing easier, or left in it's cold worked state to make the finished part stronger. This property of steel is utilized around the world to make very strong, and inexpensive parts. A variety of other heat treatments are available to perform similar tasks.
In summary, the thermal properties of steel are considered a asset, because it allows us to manufacture things with high strength inexpensively. Using a material that is strong at all temperatures will increase costs. Such materials do exist but steel isn't one of them.
Disclaimer: If you find anything above factually incorrect, I was a C student in material science.
One of our competitors trademarked the term "hypothesis". From now on, we will call them "boneheaded ideas".
The jet fuel had almost nothing to do with the collapse other than it was a big match that set everything else on fire. The vast majority of the fuel was consumed in the initial fireaball or within a few minutes of the crash. The critical part was the removal of fire protection and the severing of the sprinkler stack. The solution is a more robust and adhesive fire coating (like foam bead containing cement with polymer binders added to the liquid portion) and redundant sprinkler stacks. NIST estimates the cost increase to be between 2 and 5 percent for ALL of their building code enhancement guidelines including the biggest cost of increase emergency stairwell size. To me this seems like a small price to pay for general emergency preparedness and can most likely be offset over the lifetime of the building through decreased insurance premiums.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
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.