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Domain: corrosionsource.com
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Comments · 6
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Re:Not great for everyone
And helium is very expensive !
Dude, either you're using an impossibly large volume of gas, or your local helium guy is taking you for a (balloon?) ride.
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Re:Hydrogen
The answer is no...
Can we safely transport Hydrogen. Yes... Can we safely transport Hydrogen and float? Answer is no...
Using Hydrogen means we need to weigh how much safety to reasonable expect. Unless of course we happen to develop some super tensile spider web type technology that can be used to safely contain hydrogen. Though I would not trust that technology worth a darn. From the periodic table Hydrogen is just too darn unstable... Look at the periodic table and see what it neighbors are...
http://www.corrosionsource.com/handbook/periodic/
Li, Na, K, etc... Not exactly the stable sort of chemicals... -
Re:Oh great
Ahhh.... Welll.... If we run out helium we are actually kind of buggered. Look at the periodic table.
http://www.corrosionsource.com/handbook/periodic/
The reason why we use Hydrogen, or Helium is because they are light and actually make it worthwhile to float. Hydrogen is the lightest because it has a weight of 1. Below that is Li which is slightly heavier than H, but just as unstable as H. Though if you look at the noble gasses below Helium is Neon, which has a weight of 10. In other words 5 times heavier. Actually heavier than air because air is O, and N, which are both lighter than Ne.
In the end this boils down to use H, or He. And if He runs out well then we are buggered because we can't just created another base element.... Or we live with the dangers of H. -
Re:Movie AND Film?
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Re:Your numbers a little off...Correct, it is biased. Everything is biased except raw numbers (not including statistics). A more important question would be, "Did you find any falsehoods in that source?"
That said, I'll answer a few of your good points.Embrittlement resulting from bombardment with neutrons, usually encountered in metals that have been exposed to a neutron flux in the core of a reactor. In steels, neutron embrittlement is evidenced by a rise in the ductile-to-brittle transition temperature. - results of a Google search
It would be naive to think that nuclear engineers are not intimately familiar with this phenomenon. Can you point out an occurance of neutron embrittlement that has gone unchecked and/or caused an accident? Nuclear power has been in use for fifty years. Surely if it were a serious problem, it would have shown itself by now.
Second, I assume that your 2,000 year assessment was by taking an expected uranium reserve of less than 50 years and multiplying by the expected efficiency of IFRs over LWR/BWRs? Unfortunately this fails to take into account the amount of spent fuel sitting in pools at nuclear plants. This is fuel as well and still retains approximately 98% of its energy potential. Yes, the current generation of LWR are that inefficient and current legislation does not allow nuclear fuel reprocessing. I also fails to take into account the aging stockpiles of nuclear weapons. This is fuel as well. Even without getting into uranium collection from the oceans, I'm sorry sir, but the longevity of this fuel source far exceeds two thousand years.
Third, sodium is indeed highly reactive with water and air. But liquid sodium and metallic sodium have been used successfully in various industries for some time. There is a great deal of experience with that substance. As far as the claim, "Every fast-neutron sodium reactor design ever built has had some serious accidents related to sodium," this is false. Yes, there has been the incident in Japan in 1995 -- the Monju reactor accident which caused no deaths, no injuries, and no damage to the reactor itself. The EBR-II, the prototype test bed for IFR/AFR reactors, was in operation for twenty years with a sodium pool. "Every" fast-neutron sodium reactor? By the way, just how many have been built thus far? (I don't know, but it's certainly a very small number -- statistically insignificant)
In response to your plutonium usage as a bomb, it is important to note that not a single bomb has ever been made from traditional nuclear power-generated spent fuel. Ever. In any country. That said, one can make a bomb from Uranium as well. As far as plutonium goes, the plutonium that is most useful to power generation (the heat-generating isotopes) are precisely the kind of plutonium you don't want for weapons. Plutonium-bearing material taken from anywhere in the IFR cycle is so ornery, because of inherent heat, radioactivity and spontaneous neutrons, that making a bomb with it without chemical separation of the plutonium would be essentially impossible - far, far harder than using today's reactor-grade plutonium.
Now keep in mind that plutonium is never intended to leave an IFR. Ever. There are no shipments "to and from" an IFR. There are only shipments "to." The processing facilities are on-site. And the only plutonium to enter the site is plutonium that already exists in the form of spent fuel or weapons. IFR/AFRs, if you completely disregard the power generation qualities, are still the only large-scale method of disposing of transuranics that I am aware of. What's the alternative? Yucca Mountain for 10,000 years?
Once again, because this bears repeating, spent fuel from a nuclear reactor designed solely for power generation has never before been used by any country to make a nuclear weapon . It would be -
Re:Sensible?A mini FAQ
Why is diving...
Expensive?
It's an extreme enviroment, and we are fragile creatures. Even unmanned machines have to contend with fantastic pressures, and the special care that goes with an enviroment like salt water. Many of the considerations involved with such ambitious undertakings require that the equipment be almost unique. This combined with the very small market, prevent the advantages of large economies from easing much of the burden. When factors like the on-site nature of the research, the technical and saftey demands are fully factored; each excursion demands a wide array of very talented people, in adverse to extremely adverse consitions, be available to support it.
With many supermaterials, and magic a ways off, perhaps never to reach fruition, this will always be so.
Difficult?
Aside from the temperatures, and the long term care of devices that spend their lives in salt water. There's all the stuff that needs to be brought with the people for the people. Food, of course, science is hard enough without starving. Where food goes, waste follows.
Boats aren't planes, and the ocean is very large. Further more weather can be less than cooprative. So not only does it take a long time to get to the place miles above where one wishes to investigate, much waiting might be required. And then there are the large weather systems that can threaten even large craft, and seasonal trends which might even make some locations off limits for parts of the year. One might ask the question, "If no one can go to Vermont in the fall, do the trees there change color?"
Then there is the actual dive. The trip down can take hours, and might have to be aborted for any number of reasons. If humans are making the trip with the gear, well then an atmosphere has got to go with them. CO2 poisoning, is probably not the best way to go, but I imagine implosion has got to be one of the less painful (but most dramatic) ways to make an exit. At least with humans, thanks to the drive for self-preservation, and the diligent efforts of those maintaining the craft, the loss of craft itself is unlikely. Unmanned craft, costing perhaps millions, are not always so lucky. Of the problems, this one might has a techological solution likely to be employed in the near term.
Slow?
Well, aside from water being "sticky" and dense. It also holds gasses in solution. This causes cavitation. (Links here, on metal fatigue, and corrosion, might also be of interest.) Which is EXTREMELY BAD.Cavitation Corrosion. Cavitation is a special case of erosion corrosion caused by the formation and collapse of vapor bubbles in high-velocity fluid flow near a metal surface. This produces surface cavities and causes the surface to appear spongy. The bubbles, caused by the conjoint influence of high velocity and geometry of the flow path, which induces hydrodynamic pressure differences in the flowing stream, subsequently collapse with considerable impact at the metal-liquid interface sufficient for plastic deformation of some metals. It also disturbs any protective film that may exist on the metal surface. This type of damage has been observed on water-turbine blades, ship and boat propellers, pump impellers, pipes carrying fluids at high speed and pressure, water cooled sides of internal combustion engines, etc. Cavitation damage can be prevented or considerably reduced by changing design to reduce hydrodynamic pressure difference in process streams as much as possible; using superior materials of construction, such as stainless steels; coating vulnerable components with resilient coatings of rubber or plastics; operating the pump at a speed and head that minimizes bubble formation.
-- ASM
There is supercavitation, but yeah, unless you're just tryi