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MIT Designs Less Expensive Fusion Reactor That Boosts Power Tenfold
jan_jes writes: Advances in magnet technology have enabled researchers at MIT to propose a new design for a practical compact tokamak (donut-shaped) fusion reactor. The stronger magnetic field makes it possible to produce the required magnetic confinement of the superhot plasma — that is, the working material of a fusion reaction — but in a much smaller device than those previously envisioned (abstract). The reduction in size, in turn, makes the whole system less expensive and faster to build, and also allows for some ingenious new features in the power plant design.
You do understand that Chernobyl used a flammable material for the neutron moderator and poring water onto the plant, where necessary, caused a significant amount of radiation to become airborne, even after the steam explosion blew it apart. What eventually brought the situation under control was the partial burying of the core in lead and sand to reduce the radiation so a makeshift containment building could be hastily assembled over the blown apart reactor.
Also, the problem with Chernobyl was more about the lack of safety engineered into the system, than a fault of Nuclear power persay. In Soviet Russia times the imperative was to generate power cheaply, and NOW. They literally built a house of cards, with inadequate safety, cut corners on all kinds of safety systems, and had complex interactions between seemingly unrelated systems. Then they skimped on operator training and safety standards. It's no wonder that this reactor design didn't blow up more often. It truly was an accident waiting to happen.
Modern reactors can be designed to be fail safe. One design I saw claimed that you could literally walk away from it running at full power and it was both thermally and physically safe. It would insert the control rods if it got too hot and there was nothing that could stop it. At that point, even a total loss of coolant pumps would not result in a melt down as a number of plugs would melt, flooding the area around the containment vessel and allow the conduction/convection cooling of the core. Even then, if the core continued to heat, it would release the fuel assemblies which would fall into deep pools of reserved cooling water and end up far apart in the bottom of the containment building. All this didn't require ANY operator input, or power to accomplish, it was totally mechanical and automatic and only required the reactor containment system to remain in tact and right side up.
There are a number of very safe and practical designs for nuclear power today, it's just impossible to get a permit to actually build one because the environmentalists won't let that happen..
"File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
Contrats, of all of the many thousands of radioactive isotopes created by man or nature, you picked the one with the 32nd longest known half life. Try compared to nuclides in general.
There's a balance in terms of half life. The shorter the half life, the more intense the radiation - but the shorter you have to deal with the problem. The longer the half life, the less intense the radiation, but the longer you have to deal with the problem. The only way around this is a product that has a very low energy in its radioactive decay. And indeed, that's just what tritium is .
Tritium's decay energy is only 18.591 keV, which is tiny by the standards of radioactive decay - by comparison, U235's decay energy is 4678 keV - 251 times more intense. Furthermore, alpha radiation, while harmless outside the body (like tritium's ultra-weak beta), is (unlike beta) terrible inside it - its biological effectiveness is 20x that of beta. Hence a decay from a atom of U235 inside of you is 5032 times more damaging than a 18.591keV electron (beta). On top of this, you have biological half lives. Uranium's is only slightly longer than tritium's, 15 days instead of 12. But, again, U235 is not normally a problematic radioisotope. 239Pu, 90Sr, 226Ra, 45Ca, etc have biological half lives so long that they're effectively with you until they decay or you die. Oh, and on top of all of this? All of the energy of beta decay doesn't go into the electron; a higher percentage goes into the muon antineutrino, which escapes harmlessly off into space. The average energy of the beta particle from tritium decay is only 5.694 keV. Net result? Before controlling for the difference in half life, U235 is 20540 times worse for the body than tritium.
Now, of course, due to 235U's incredibly long half life, its radioactivity rarely a problem - which is why fresh fuel rods are not considered very dangerous, but spent ones are. People's concerns in nuclear accidents center around the fission products: strontium, iodine, plutonium, etc - things with shorter (but still problematically long) half lives and strong biological effectiveness. Versus them, the ridiculously low energy tritium is almost irrelevant in terms of biological effect, even if present in similar quantities. Combined with the very small amount of tritium that's in the torus at any point in time, it's just simply not even remotely comparable.
Did I even bother to mention that gaseous tritium tends to rapidly escape wherever it is and ascend up and out of the atmosphere? Tritium in the form of heavy water can be problematic in higher quantities, but of course, there's no "higher quantities" of any form of tritium in the torus.
I'll never forget the last thing grandma said to me before she died: "What are you doing in here with that knife?!?"
At the ICOPS conference (International Conference on Plasma Science) I asked a couple of professors what they thought of this.
They thought it was pretty telling that Lockheed wasn't investing a lot more money in this concept than they are.
If Lockheed isn't putting significant money into it, maybe you should think twice about putting your money (figuratively speaking) into it.....
That said, I really hope Lockheed does succeed with this, and starts shipping units like crazy and displacing coal power production worldwide.
--PM
Do you want to live near nuclear plant? I don't, no matter how new and shiny with latest "bug-free" design it is.
Well done, NIMBY. I hold you arseholes partially responsible for the fucking mess we're in today. Thanks so much for your efforts!
..Mullah or Pope, Preacher or Poet, who was it wrote: "Give any one species too much rope and they'll fuck it up"?