Fusion-Fission System Burns Hot Radioactive Waste 432
An anonymous reader writes "A hybrid fission-fusion process has been developed that can be used in some traditional fission reactors to process radioactive waste and reduce the amount of waste produced by 99%. This process uses magnetic bottle techniques developed from fusion research. This seems like the first viable solution to the radioactive waste problem of traditional nuclear reactors. This could be a big breakthrough in the search for environmentally friendly energy sources. Lots of work remains to take the concept to an engineering prototype and then to a production reactor."
One small hitch... (Score:5, Interesting)
First, they have to get sustainable fusion working, then they can installed the Super-X Divertor to bleed off neutrons to burn fission waste.
Why not use safe, proven technology [nationalcenter.org] available TODAY to burn 99% of current fuel AND WASTE?
Re:Neat technology (Score:5, Interesting)
Life Cycle Analysis (Score:5, Interesting)
This idea was (in some sense) around in the 1960's, believe it or not.
The high neutron flux produced means that the CFNS would itself become radioactive, and the steel of its construction weakened by neutron irradiation. I would like to see a life-cycle analysis to make sure that the total waste consumed was more than that produced by the CFNS itself.
This general issue is why I would like to see a lot more emphasis places on He3 fusion, and also on linear fusion devices. (He3 fusion, either He3 - Dt or He3-He3, produces much less neutron flux. To me, the end goal would be to have nuclear fusion power that did not produce radioactive waste, which ITER definitely will do. Linear fusion is for spacecraft propulsion, of course - it is thought to be much easier technically than making a tokomak work.)
Re:One small hitch... (Score:5, Interesting)
You know there is no problem sustaining a fusion reaction with todays tech, the problem is sustaining a fusion reaction that has a net surplus of energy.
There are even tabletop fusionreactors that are used as a source of neutrons.
The point of this tech is to scale the fusionreactor up so you get alot of neutrons to bombard the sludge, the fusion doesn't need to generate any energy.
Re:One small hitch... (Score:3, Interesting)
A couple of questions.
1) Are current fusion reactors able to provide the necessary neutron flux to assist a fission reactor in burning this waste?
2) Is the energy generated by the boosted fission enough to power the fusion reactor if you don't have the luxury of a self-sustaining fusion reactor?
If either answer is no, I'd rather see IFR technology put into place starting now than wait for this to become feasible.
Transmutation of waste (Score:5, Interesting)
I'm also guess here. A decade ago, Los Alamos pioneered Accelerator Transmutation of Waste. There the idea was you bombard high level waste with a particle beam to, ironically, make it even higher level waste. The clever thing was this. The higher the radioactivity the shorter the half life.
The plan was to convert things with halflifes of 50,000 years to half lifes of hours. An insanely clever idea. But it never got much funding.
I'm guessing that this Fission/fussion system is probably playing the same game. Fusion makes for heavier nuclii, which if they are not stable, tend to be even short lived as a general trend.
Re:Weapons Grade Production? (Score:5, Interesting)
That was the consequence of materials costing more than manhours. Now thanks to industrialization and automation, manhours are vastly more expensive than material, simply because one manhour produces 1000x more material than it did before. (In the grand scheme of things, the cost of either is a function of its exchange rate with the other.)
Our allegedly wasteful modern society is wasteful of the visible component (material) because it is so careful to conserve the invisible component (manhours). Unfortunately most people are concrete-bound and so do not understand what's going on.
Indeed.
Re:One small hitch... (Score:4, Interesting)
1) Yes.
2) Yes.
We can build stable, multi-Megawatt Fusion reactors that are close to break even. The basic idea is used by H-bomb's. They use the high neutron flux from fusion to increase fission yield. One of the basic fission problems is it becomes hard to have a stable reaction as you scale things up. You can use lot's of crappy fuel in a huge mound, but you have little control over what that pile is going to do. And as you burn fuel you change the nature of the fuel in such a way that it becomes even harder to maintain stability. If you can have a fixed source of neutron that feeds the pile you can setup a multiplier where 1 neutron in produces X reactions, but it's not self sustaining so it can't get out of control.
PS: Breeder reactors are far less stable than non breeder reactors. Think of a traditional oil lamp filled with gasoline. With with great care it can work, but it's just not as stable as heavy oil.
Re:Weapons Grade Production? (Score:5, Interesting)
As a former nuclear engineer you must also be aware that nuclear material can and is frequently used with virtually no risk to anyone.
I too am scared by unregulated, corner-cutting businesses working with the stuff. But no more afraid of a commercial farmer breeding a potentially lethal or ecologically dangerous super-crop though... and that's legal. So is colliding particles that may or may not cause the end of the planet.
The nuclear industry exists now, and there have been tremendous strides in the technology and safety. To suggest that we should not encourage an industry that may, with advances such as this article discusses, result in nearly zero net effect on the environment is pretty awesome if you ask me.
Honestly, nuclear fission is probably the best energy source we could pursue right now. Why, because we can do it now with virtually no waiting and no chance of finding out later that we rushed into something we shouldn't have (like corn ethanol).
Re:Mr. Fusion (Score:5, Interesting)
What we need is a mainstream movie and miniseries about the hazards of coal; perhaps going through the life of a Chinese coal miner?
Oh, and point out the cost/hazards of solar and wind while you're at it.
Re:Transmutation of waste (Score:3, Interesting)
As a byproduct, of course, the decay produces a huge amount of heat, easily enough to feed a steam turbine to power the beam and other stuff.
I wish the article had mentioned something about it's energy generation capabilities. By the sounds of it, it probably doesn't process 'raw' waste out of cores, instead treating the waste resulting from reprocessing them to sort out the still usable fuel elements.
I'm still for using breeder reactors.
Re:Transmutation of waste (Score:1, Interesting)
ADS (accelerator driven systems) have other problems as well, basic ones and the research on those is "still on the way".
In theory, the idea to shoot neutrons on nuclear waste and therefore transmutate it into something that you can use in a fission reactor again is good. But:
- You need a VERY high powered linear accelerator for your neutrons that is also VERY stable (max downtime less than half a dozen times for less than "minutes" each time). Those accellerators simply do not (yet) exist.
- You have high powered neutrons everywhere. Therefore, they'll activate anything around (your accellerator, your reactor, everything). You have new waste to dispose of.
- It's not trivial to build an interface between "reactor" and "accellerator". Either you have no material, then particles from the reactor will pollute ("make less good") the vacuum in your accellerator or you have a "window" that will get blown to pieces by the highy energy neutrons over time. Which material you will use there? Unknown.
- You must reasearch what sort of reactor is best for such an setup. What sort of cooleant do you use? What setup? All that is unknown.
There are other very, very basic problems and those neutron-plans aren't "the solution".
Re:One small hitch... (Score:5, Interesting)
The solution is to educate people about the pros and cons, and reasonable people will start siding with nuclear. (Of course, whether or not people are reasonable is another question entirely...)
Re:I'm selling a bridge! Cheap!! (Score:5, Interesting)
Unfortunately much (most?) of the US public thinks that:
Everything that's "natural" is good. (Umm... what about ricin? Perfectly respectable "natural" product...)
Everything "nuclear" is bad. (The parent is potentially a good counterexample).
Everything "renewable" is good. (Using corn-based ethanol as a fuel source is a really bad idea ... there are better sources that have less environmental and economic impact).
Etc. Unfortunately the state of science education in the US is in such a sorry state that too many people are unable to think rationally about many of the choices facing us - they'll pay more attention to what Oprah or Paris think about some scientific question than they would to the scientists and engineers who actually do know something about those choices.
For all those people, I've got a bridge for sale in Manhattan! Cheap!! Buy it now while you have the chance, because it'll sell fast!!!
:-( :-( :-( Our country is so screwed... hopefully some of the rest of the world can keep civilization going until the nitwits here die out ... :-( :-( :-(
Re:One small hitch... (Score:3, Interesting)
The anti-nuclear lobby has nowhere near the kind of clout that you seem to attribute to it. I can think of only 1 reactor project off the top of my head in the United States that was canceled due to environmentalist pressure (the Shoreham plant on Long Island).
It's often claimed that Three Mile Island was the catalyst that caused the eco lobby to sink nuclear power projects in the United States. What's not often mentioned is that power companies and their investors took a hard look at nuclear power after 3 Mile Island. Even if not a single person is injured in a reactor cock-up and any radioactive emissions are completely contaiend, you suddenly have a massive cleanup project on your hands that will be enormously expensive to complete. It was not lost on power companies and their shareholders that an American nuclear plant, with what was assumed to be the highest safety standards and top quality operators, could be turned from a $2 billion asset to a $1 billion liability in the space of half an hour.
The majority of nuclear plants that have been canceled over the past 20 years have been canceled not because of environmentalist pressure, but simply because the ROI wasn't there. It has also not helped that the economic policies of the U.S. have tried to keep fuel prices artificially low for the better part of three decades; indeed one of the great dangers of the current economic situation is that fuel prices are ridiculously low and the impetus that may have existed to begin seriously working on alternative sources as the prices were driven up over the past years is being lost. Once the world's economic engines begin to come out of their torpor (however long it may take) the U.S. may find itself in a position where the result of energy companies consistently only caring about short-term profits will leave us in a state where the massively inflated prices of last summer will seem like a bargain.
Re:Weapons Grade Production? (Score:2, Interesting)
Plutonium generated from normal reactors have too high a content of Pu-240 to ever be weapons-grade. It gets bombarded with neutrons for too long, Pu-239 + n -> Pu-240. The containment shell makes it quite cumbersome (to the point of shutting down the reactor for weeks, I believe), so you can't just remove it earlier. So, If you have a containment shell around your reactor, you can't really use it to make weapons grade plutonium.
Not true
Thanks to Jimmy Carter declassifying this
http://www.ccnr.org/plute_bomb.html [ccnr.org]
The Department of Energy is providing additional information related to a 1962 underground nuclear test at the Nevada Test Site that used reactor-grade plutonium in the nuclear explosive.
SPECIFICALLY:
A successful test was conducted in 1962, which used reactor-grade plutonium in the nuclear explosive in place of weapon-grade plutonium.
Everyone now knows it's possible to use reactor grade plutonium in a bomb.
Re:Weapons Grade Production? (Score:2, Interesting)
Well one approach would be to not do anything and live with a reduced yield, i.e. 1kt-3kt (depending on who you believe) rather than 10kt.
http://www.ccnr.org/plute.html [ccnr.org]
Designing and building an effective nuclear weapon using reactor-grade plutonium is less convenient than using weapon-grade plutonium, for several reasons.
Some nuclear weapons are typically designed so that a pulse of neutrons will start the nuclear chain reaction at the optimum moment for maximum yield; background neutrons from plutonium-240 can set off the reaction prematurely, and with reactor-grade plutonium the probability of such "pre-initiation" is large. Pre-initiation can substantially reduce the explosive yield, since the weapon may blow itself apart and thereby cut short the chain reaction that releases the energy.
Nevertheless, even if pre-initiation occurs at the worst possible moment (when the material first becomes compressed enough to sustain a chain reaction) the explosive yield of even a relatively simple first-generation nuclear device would be of the order of one or a few kilotons. While this yield is referred to as the "fizzle yield," a one-kiloton bomb would still have a radius of destruction roughly one-third that of the Hiroshima weapon, making it a potentially fearsome explosive. Regardless of how high the concentration of troublesome isotopes is, the yield would not be less.
It's possible that the North Koreans did this. In fact they messed up even more because they got less than one kt.
http://www.sciam.com/article.cfm?id=kims-big-fizzle [sciam.com]
Soon after the news broke that North Korea claimed to have conducted a nuclear test, experts realized that the blast had been much smaller than is usual for a first device. Nuclear explosions are measured in kilotons, an energy release equivalent to that of thousands of tons of TNT. Most countries' first tests range from five to 25 kilotons. For example, the U.S.'s 1945 "Trinity" test had a yield of about 20 kilotons. Yet estimates of the North Korean test clustered around half a kiloton. Reportedly, North Korean officials had told China to expect a blast of four kilotons.
Sci am speculates they used reactor grade plutonium and didn't do anything clever or that they got the implosion design wrong. Or maybe both.
Re:Mr. Fusion (Score:2, Interesting)
Re:Mr. Fusion (Score:2, Interesting)
Solar power generates electricity from solar radiation that would normally be bounced back out of the atmosphere for some 90% orso. This energy is converted to heat in your microwave and electric car. Hence raising the temperature of the earth.
Wind generators have the tendency to chop up birds. As long as they're doves I don't mind much, but greenpeace kinda thinks otherwise. The generated electricity also gets converted to heat, but the friction between the air-particles that you slow down during power generation would've done thesame so I think that's about equal. (haven't calculated that)
Wave generators generally do thesame thing with fish as the wind generators do with birds, but there are a few types that are benign. They use the wave action in a column of air to push air back and forth in a tube, creating an airflow to generate power. This type when using a mesh in the air side, won't hurt birds or fish, so Greenpeace shouldn't have anything to complain about that, but I'm afraid they'll find a way anyway. Wacko's.