Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Ask MIT Researchers About Fusion Power

Soulskill posted more than 2 years ago | from the can-you-build-me-a-reactor dept.

Power 318

Nuclear fusion power is the process of fusing light nuclei together to release energy, and ultimately, to put electricity on the grid. Today, we have six researchers from MIT's Plasma Science and Fusion Center here to answer your questions about fusion power, tokamaks, and public support and funding in the U.S. for this research. The Obama Administration's budget request for fiscal year 2013 is paying for the U.S. share of ITER construction out of the domestic program, starting with the closure of the MIT fusion lab. The interviewees are ready to answer technical and policy questions, so don't be shy! And, as always, please break unrelated questions into separate posts. Read on for information about the researchers who will answer your questions.Dr. Martin Greenwald is a Senior Scientist and Associate Director of the MIT Plasma Science and Fusion Center. His experimental work focuses on turbulence and transport, density limits, and pellet fueling of magnetically confined plasmas. More recently, Dr. Greenwald has been heavily involved with data management, computation, simulation, networks, and remote collaborations for fusion research.

Professor Ian Hutchinson is interested in plasma control in tokamaks, as well as spatially resolved measurements of the radiated power coming from the plasma. He is the author of the standard fusion textbook Principles of Plasma Diagnostics. Prof. Hutchinson also works on particle-in-cell simulations of astrophysical and laboratory plasmas.

Assistant Professor Anne White researches turbulence phenomena on the Alcator C-Mod tokamak, developing new diagnostics to resolve the small fluctuations which cause energy and particles to leak out. She is the recent recipient of the U.S. Department of Energy Early Career Award.

Professor Dennis Whyte pursues research into plasma–material interactions; that is, the way the hot plasma in a magnetic fusion reactor interacts with the surrounding solid materials walls. His team is also developing novel diagnostics for fusion nuclear science, which is critical as fusion reactors start producing power (and neutrons) over long periods of time.

Nathan Howard and Geoff Olynyk are Ph.D students on the Alcator C-Mod project. Nathan, who is in the final year of his studies, studies turbulent transport phenomena experimentally and through simulation. Geoff, in his fourth year, is working on disruption mitigation, which is a way to quickly and safely shut a tokamak plasma down in a few thousandths of a second.

cancel ×


Sorry! There are no comments related to the filter you selected.

Polywell fusion (4, Interesting)

mknewman (557587) | more than 2 years ago | (#39440529)

What do you think of the efforts at [] and [] ? They seem to be making real, measurable and open results but the mainstream physics community seems to ignore this progress.

Re:Polywell fusion (0)

Anonymous Coward | more than 2 years ago | (#39440615)

this. Dr. Robert Bussard had a strong belief in the practicality of the truncated cube reactor right up to the time of his death. Many people wonder why it hasn't gained more traction.

Re:Polywell fusion (0)

Anonymous Coward | more than 2 years ago | (#39440709)

Also throwing my vote in for this question to be answered

Re:Polywell fusion (1)

kiick (102190) | more than 2 years ago | (#39441135)


Re:Polywell fusion (1, Insightful)

BlueParrot (965239) | more than 2 years ago | (#39440955)

At least polywell is complete bull. You often see these kind of things pop up. They make a bunch of claims on webpages, blogs, conferences and so on, but when it comes to peer reviewed journals they're very lacking. Sometimes they claim their results have been reproduced, but it's again almost impossible to get any details.

How can I be so sure? Well, basically the polywell crowd is claiming they can arrange a magnetic field in such a way as to maintain a non-maxwellian velocity distribution without using energy to do so. This violates the 2nd law of thermodynamics. In addition the polywell concept was heavily debunked some years ago, by a scientists who showed that the energy needed to maintain a mono-energetic distribution was more than what fusion would produce. Instead of addressing these concerns the polywell supporters basically just accuse their critics of not understanding polywell, without giving any real explanation of how it works beyond vague descriptions of the general concept.

I've seen enough of it to call it for what it is. It's a fraud intended to attract investors, and it will never produce anything useful.

Re:Polywell fusion (4, Interesting)

Rei (128717) | more than 2 years ago | (#39441091)

It does not violate the 2nd law of thermodynamics beause it's not claiming to do so without energy. There is a constant energy input into the system. As Rider's work shows (Rider being the "scientist who showed..." that you mention), you can maintain fusion in a non-Maxwellian plasma but only if you selectively accelerate low energy ions instead of the bulk plasma.

Does Polywell do that? I doubt it, but I'm not versed enough to make a judgement.

Re:Polywell fusion (0)

Anonymous Coward | more than 2 years ago | (#39441309)

Because both sites are fraudulent and are not based on any kind of real science. It's snake oil being served up to people too stupid to see through the lies.

Light nuclei (3, Funny)

Soruk (225361) | more than 2 years ago | (#39440549)

> fusing light nuclei together

Light nuclei? They're just photons.

Re:Light nuclei (0)

Anonymous Coward | more than 2 years ago | (#39440699)

> fusing light nuclei together

Light nuclei? They're just photons.

The article is referring "light nuclei" as atoms with low atomic mass. For example fusing Hydrogen with a mass index of 1 to Helium with a mass index of 2.

Re:Light nuclei (0)

Anonymous Coward | more than 2 years ago | (#39440759)

Whoosh. You missed the very obvious play on words being made there.

Re:Light nuclei (-1)

Anonymous Coward | more than 2 years ago | (#39441323)

I "get" the play on words. The play on words is more ignorant sounding than funny. I'd figure i'd spread some edumacation just in-case it was not intentional.

Re:Light nuclei (1)

omnichad (1198475) | more than 2 years ago | (#39440915)

Yeah, it took me 3 tries reading that bit to realize what they were saying.

Re:Light nuclei (3, Funny)

arthurpaliden (939626) | more than 2 years ago | (#39441149)

Are you positive?

Power Loss Scenario in Alcator C-Mod? (5, Interesting)

eldavojohn (898314) | more than 2 years ago | (#39440555)

Not to raise any fears -- rather out of genuine curiosity -- what happens when the magnetic fields that hold the 90,000,000 degrees Celsius plasma in place fail or loser power on the Alcator C-Mod? I understand it's probably in prototype mode but what sort of safety advantages or disadvantages do Alcator C-Mod designs offer over conventional large scale designs? Does the plasma come into contact with the toroidal super conducting coil? Then what?

Re:Power Loss Scenario in Alcator C-Mod? (4, Interesting)

benjfowler (239527) | more than 2 years ago | (#39440813)

Ultimately, you'd have to ask an expert -- but I do know that there is a fairly substantial first wall between the plasma and the coils (and just as well -- a quench on a machine the size of ITER would truly be something to behold). Not sure what you mean by Alcator C-Mod being 'unconventional' -- were you referring to the superconducting magnets, as opposed to copper ones?

Particularly on large machines, during disruptions, there is potential for serious damage to the first wall from heating, runaway electrons, and substantial mechanical forces. Disruption mitigation is considered a priority for ITER, because the problems get worse for large machines, especially research machines not designed with the duty cycles of actual, real power plants.

The plasma DOES come in contact with the 'divertor', which is a part of the interior of the reactor where the cool outer edge of the plasma outside the last set of closed field lines is drawn out over a large surface area to trap and remove the helium 'ash' and other contaminants from the plasma. The plasma is held tightly within the closed magnetic field lines within the torus, and only the 'scrape off layer' ever comes anywhere near the walls. This is key to performance, as performance is closely related to purity (contaminants wastefully radiate away energy).

Re:Power Loss Scenario in Alcator C-Mod? (2)

mhajicek (1582795) | more than 2 years ago | (#39440991)

But do you contain the exotic particles or push them into a parallel universe?

Re:Power Loss Scenario in Alcator C-Mod? (1)

benjfowler (239527) | more than 2 years ago | (#39441353)


Re:Power Loss Scenario in Alcator C-Mod? (1)

mhajicek (1582795) | more than 2 years ago | (#39441373)

Stargate Atlantis reference.

Re:Power Loss Scenario in Alcator C-Mod? (0)

Anonymous Coward | more than 2 years ago | (#39441531)

Stargate Atlantis reference.

I was going to go with Spiderman II reference, myself.

I think the most important question... (4, Interesting)

monsted (6709) | more than 2 years ago | (#39440577)

When will fusion power my house?

2050 (4, Funny)

Anonymous Coward | more than 2 years ago | (#39440703)

just skip the Microwave Power Plant in 2020

Expanding on this: (5, Interesting)

Anonymous Coward | more than 2 years ago | (#39440987)

Could you break down the various barriers/bottlenecks to the introduction of commerical fusion?

What are the technical problems in the state of the art, what other factors (political, economic, etc.) do you see at play?

How do you and your labs collaborate with others, and how is technology transferred? Is there much international cooperation?

Are there policy communities (China, India?) that might be more primed for the introduction of fusion technology into their grids than in North America? What would need to happen for North America to start using fusion?

I have many more questions, but those are the ones that popped into my head first. This is such a great opportunity -thank-you for taking the time today!

Re:I think the most important question... (1)

who_stole_my_kidneys (1956012) | more than 2 years ago | (#39441029)

Or vehicle?

Re:I think the most important question... (1)

ArsonSmith (13997) | more than 2 years ago | (#39441211)

or my DeLorean?

Re:I think the most important question... (1)

DigiShaman (671371) | more than 2 years ago | (#39441427)

When you get your flying car?

All that dough! (0)

Grindalf (1089511) | more than 2 years ago | (#39440581)

If I don't see a glowing doughnut filled with plasma pumping out exawatts of juice by next Tuesday, there'll be heck to pay! :0)

What's the problem in building the future. (5, Interesting)

Bucc5062 (856482) | more than 2 years ago | (#39440623)

As a non-scientist, what are the biggest stumbling blocks for effective fusion reaction? is this truly throwing money down the energy hole, or are there verifiable, measurable benchmarks that lead us from one point to the next. Something like, we got x to work, now we need y, when we get y, we get z and then we get fusion. Is it technology holding us back, politics, or the science?

Re:What's the problem in building the future. (5, Informative)

Dynetrekk (1607735) | more than 2 years ago | (#39440719)

Fusion reactors generate enormous amounts of neutrons, which interact only weakly with matter. Making a reactor casing that can withstand the radiation damage and collect the heat for useful purposes (power generation, desalination of water, heating for industrial processes etc.) for long enough is extremely hard. This is expected to be the ultimate limit to how well fusion power can work. I don't have a citable source, but I got this from a talk at CERN by the guy in charge of the ITER [] project.

Re:What's the problem in building the future. (1)

benjfowler (239527) | more than 2 years ago | (#39440963)

Mod parent up. Advanced materials are a BIG issue for future machines. Everyone else recognises this, and are trying to find ways to get a head start on the problem now, instead of in 20 years time.

Re:What's the problem in building the future. (2)

tragedy (27079) | more than 2 years ago | (#39441379)

Do neutrons react weakly with matter? That's kind of news to me. In fact, the radiation damage that you mention would seem unlikely to happen if the neutrons interact weakly. Are you sure you're not thinking of neutrinos with that first line? The rest of the post seems to make sense. There are some fusion reactions which don't directly produce neutrons, such as hydrogen-boron-11, but even those would almost certainly produce some neutrons through secondary effects.

Re:What's the problem in building the future. (1)

Dynetrekk (1607735) | more than 2 years ago | (#39441493)

I'm 100% sure. Neutrons are uncharged and interact very weakly with matter compared to electrons and protons. Hence, they penetrate deeply into any material. We're talking on the order of magnitude of meters, though. Neutrinos, however, will interact only once per several thousand light years when passing through solids - that's a whole different business.

tl;dr: Neutrons interact weakly enough to penetrate, but strongly enough to be annoying.

NIMBYA (5, Interesting)

GeneralTurgidson (2464452) | more than 2 years ago | (#39440625)

How do you explain the safety/benefits of fusion to a generation of people terrified of nuclear anything?

Re:NIMBYA (1, Funny)

19thNervousBreakdown (768619) | more than 2 years ago | (#39440649)

Not In My Back Yard ... Asshole?

lower limit on tokamak design (5, Interesting)

gyepi (891047) | more than 2 years ago | (#39440637)

Are there any good guesstimates on how small a tokamak-based fusion reactor (which produces more energy than consumes) can become? Theoretical limitations on size of the reactor would have obvious implications for pragmatic issues. AFAIK there is very little limitation on how small fission-based reactors can get.

Stellerators (0)

Anonymous Coward | more than 2 years ago | (#39440647)

Do you see Stellerators, or Quasi Helically Symmetric Stellerators as being a more practical design for power generation than tokamaks?

Or not?

Does the plasma current ever hit the wall on a tokamak?

What do the numbers really look like? (5, Interesting)

Erich (151) | more than 2 years ago | (#39440661)

ITER is a hugely expensive project, and won't produce a commercially viable power generation system.

In a lot of areas where research is done on things which don't work yet -- rockets, bridges, transmission systems, etc -- there's a general idea of how things might be able to "scale up" to meet the goals.

Is tokamak fusion really in sight of being commercially viable source of energy? If we need unobtanium to make a commercially viable reactor, wouldn't it make sense to wait until the materials are viable before making even larger tokamaks? What do we learn from making these new, bigger, more expensive reactors?

Or are we trying to build ever-bigger spark gap transmitters as a way to make radio better? Maybe we should look at other schemes?

Or, alternatively, we know of a nice, large, gravity-fed fusion reactor fairly nearby, is the engineering simpler to harness energy from that on a large scale?

ISS = 5x ITER (1)

tp1024 (2409684) | more than 2 years ago | (#39441125)

I wouldn't call ITER cheap either, but it's an international project (and the Chinese aren't locked out, as is currently the case on the ISS) and the cost is distributed over several decades and billions of people. Germany's share is on the order of $2bn over 35 years. That's $0.70 per capita per year. Much less than a lottery ticket, but with much better chances than 1 in 140mio for winning the jackpot.

Careers in fusion (5, Interesting)

benjfowler (239527) | more than 2 years ago | (#39440663)

As practicing researchers, can you tell us about the health of the pipeline of young researchers coming into the field? Is there a glut of trained physicists at this stage, or is there still a need for trained specialists to enter the field, especially with ITER and follow-on machines coming online in the next couple of decades?

Well... (0)

Anonymous Coward | more than 2 years ago | (#39440677)

20 years is up where's the fusion you promised?

Re:Well... (1)

benjfowler (239527) | more than 2 years ago | (#39440935)

It turned out to be way harder than we expected. Remember Donald Rumsfeld and his 'unknown unknowns'?

IEC's / Fusor (4, Interesting)

claytongulick (725397) | more than 2 years ago | (#39440681)

Why aren't IEC reactors based on Farnsworth's designs taken more seriously? From what I understand, IEC's have been more effective at producing fusion, and they are cheap to build. People even build them in the garage [] . From everything I've read, no one really takes the "fusor" seriously in the fusion science realm, and it's considered a dead line of inquiry. I've never understood why.

Re:IEC's / Fusor (3, Informative)

Anonymous Coward | more than 2 years ago | (#39440957)

I spent my fusion time at NBTF (Neutral Beam Test Facility at Berkeley). Fusor type stuff is really easy and the plasma discharge is great to watch (got lots of photos). Making a few D-D fusion neutrons is easy. Making enough to be useful requires a larger machine. After a bit of quality slide rule time one ends up with a REALLY BIG tokamak or mirror machnine (MFTF, my project).
Sorry, fusor type setups are for show. I did work with a fusor like project afew years ago that might work as a neutron source, but not for fusion energy.

Re:IEC's / Fusor (1)

mhajicek (1582795) | more than 2 years ago | (#39441049)

"Good news everyone!"

Will I live to see Fusion power available? (2, Interesting)

Tragek (772040) | more than 2 years ago | (#39440685)

Is fusion power going to be feasible in the next 60 years (extrapolating my expected lifespan)?

Re:Will I live to see Fusion power available? (1)

arthurpaliden (939626) | more than 2 years ago | (#39441181)

No, but you will get your flying car.

What level of investment would get fusion going? (4, Interesting)

Tragek (772040) | more than 2 years ago | (#39440713)

Do you think a program of the size of the Apollo program could kickstart fusion to general availability? Or would a rather smaller program suffice?

Re:What level of investment would get fusion going (1)

arthurpaliden (939626) | more than 2 years ago | (#39441201)

Don't know. How much money has the government got?

Why is it taking so long? (-1)

Anonymous Coward | more than 2 years ago | (#39440715)

I keep hearing we'll get Fusion within the next 50 years, will it ever happen within the next 50 years or is this just some pipe dream ?

Patents (5, Interesting)

Anonymous Coward | more than 2 years ago | (#39440721)

Will patents get in the way of your research?

Does new technology solve safety concerns? (1)

Anonymous Coward | more than 2 years ago | (#39440725)

I've heard things like pebble bed reactors and other emerging technologies make safety concerns about 70's era reactors out of date.

With what we know now, can we make nuclear power as safe (or at least "seem" as safe) as coal and other fossil fuels? Are nuclear pundits fighting against science, or are their concerns still legitimate?

Re:Does new technology solve safety concerns? (1)

Dr_Barnowl (709838) | more than 2 years ago | (#39440975)

Your question seems to be about fission reactors - anything that involves anything heavier than iron as a fuel is not a fusion reactor.

Re:Does new technology solve safety concerns? (2)

Stellian (673475) | more than 2 years ago | (#39441453)

Well, one of the major arguments for fusion research is that fission is dangerous and dirty. If we can have clean and safe fission, there absolutely no reason to pursue the fusion pipe dream.

The most important item in the economic equation of a nuclear plant are the capital costs. If we already established fusion needs to be big in order to work, probably much bigger than existing fission plants, then we should stop spending money on large experimental fusion reactors - it is not a solution in it's current form, not if fusion can solve the same problem today.

Re:Does new technology solve safety concerns? (1)

tragedy (27079) | more than 2 years ago | (#39441539)

The safety issues you talk about for fission reactors shouldn't be much of an issue for fusion reactors. The huge problem in fusion is getting the fusion to even happen in the first place. Pretty much every system for getting it to work involves carefully pumping in a lot of energy in a controlled manner in some way or another to keep the fusion going. If the equipment regulating the fusion stops working, the fusion just stops. You shouldn't really be able to get a melt-down type situation where the fuel melts and pools and you have a self-sustaining reaction. You could still certainly get a boom of some sort from, for example, some sort of magnetic plasma containment failing. Then you have equipment damage and a radioactive cloud, but the reaction will have completely stopped. So, the maximum amount of pounding the containment vessel might have to take should be easy to calculate (for a nuclear physicist anyway) and a safe containment vessel could be designed. Not that it would ever be 100% safe. No industrial endeavour ever is. It would almost certainly be safer than a fission reactor however.

Future Prospects, Laymen Versus Experts (4, Interesting)

Iskender (1040286) | more than 2 years ago | (#39440733)

From the outside fusion research looks like a desperate field that's always struggling with its fundamental research/engineering questions. I know more than most laymen: I know the reactions work, I know the sun is powered by (very slow) fusion, I know fusion reactors have produced at least around 50% return on the electricity put in. Still, it feels like it's possible it'll never work, even knowing that difficult problems take time to solve.

This is the outside view. What does the future of fusion look like when you experts look at it from the inside? Does it look like a gamble? Or does it look more like "just give us proper funding and we'll give you your reactor."?

Are Tokamaks practical? (2, Interesting)

Anonymous Coward | more than 2 years ago | (#39440745)

The late Dr. Bussard of EMC2 [emc2fusion. org] claimed that the fundamental concepts of Tokamak fusion did not provide a platform for cost-effective positive-return power reactors. With the enormous ITER project reactor still not expecting positive return, at what point, if ever, will Tokamak research benefit the power grid?

Helium 3 (1)

Anonymous Coward | more than 2 years ago | (#39440779)

Would having access to cheaper Helium-3 (if we can ever get the space infrastructure to mine the lunar surface for it where there is plenty) tip the scale on development of real fusion? I presume we have yet to get past breakeven, even with using the better He3 + H reaction, so maybe a comment about the immediate probability that He3-H fusion can be made to work in a lab to generate power would be in order.

Re:Helium 3 (1)

hattom (1876314) | more than 2 years ago | (#39441377)

D-T (deuterium-tritium) has a larger reaction cross-section that He_3 + H. And given the vast abundance of deuterium (a bathtub of seawater contains a human's approximate lifetime energy suppy of deuterium for fusion) and the availability of lithium (a laptop battery likewise for lithium (and hence tritium)). So I can't see why you would suggest helium-3 at all. On the subject of breaking even JET got close to break-even in 1997 - the last time it tried. It's known that D-T reactions can be done on JET, so no additional plasma physics is learnt during D-T reactions that isn't learnt during D-D experiments. The only difference is that D-T produces fusion power, looks great in the press, but irradiates the tokamak, which on a constantly upgraded research machine, is rather impractical. If JET performs another D-T spell soon as was recently stated, then it's likely that it will beat break-even. Of course that's thermal power output, electrical conversion isn't fitted on JET, but thermal efficiency is expected to scale with R^3, hence the 20+ year need for a machine larger than JET.

What could you do with unlimited resources? (4, Interesting)

petes_PoV (912422) | more than 2 years ago | (#39440785)

Given $1Tn, the pick of the best brains in the world to work willingly on the project, a large enough location away from any and all governmental regulation and every facility you could ever need - WHEN WILL IT BE COMMERCIALLY AVAILABLE?

Re:What could you do with unlimited resources? (0)

Stellian (673475) | more than 2 years ago | (#39441233)

Given real-world resources and at the same time assuming that fusion power is an impractical fairy-tale that will never become reality, please give an estimate about the time interval we should expect societies to wisen-up and stop funding fusion projects. Does it outlast your own career ? How many PhDs will the fusion field create in the meantime ? What would be the total costs ? How much practically useful science will come of it, assuming again that the actual goal of fusion power is a hoax ?

Reactor comparison (1)

kestasjk (933987) | more than 2 years ago | (#39440807)

Thanks for taking the time to do this, I went to a lecture given by someone who worked on the JET reactor and it was fascinating.

Given that fusion creates (shorter-lived) nuclear waste, the cost of it is unknown and the timeframe is unknown, how can you justify the relatively large amounts of money going towards fusion research reactors when so little goes towards fission research reactors?

I know that the economics of larger reactor = more economical are well known with tokomaks. Does this mean you have a good idea of the minimum cost / generating capacity of the first commercial reactors, and if so what do those numbers look like?

What is the main technological challenge you're facing? Is it containing the neutron flux, getting the waste products out, separating the tritium, ...? Are there major surprises which come up or is it all working on a few well known problems for a long time?

Thanks again.

Re:Reactor comparison (2)

kestasjk (933987) | more than 2 years ago | (#39440817)

Oh and how does it feel to be working on something which you probably will never see come to fruition in your lifetime?

Re:Reactor comparison (3, Insightful)

benjfowler (239527) | more than 2 years ago | (#39440883)

This has happened many times throughout history. I'm certain the stonemasons who toiled away on Europe's beautiful cathedrals must've worked away, knowing that despite their own obscurity, they were still leaving a legacy.

Why is this more useful than exploiting thorium? (4, Insightful)

gestalt_n_pepper (991155) | more than 2 years ago | (#39440835)

I understand that long term, we would want fusion, but we face increasing energy problems over the next 50 years and severe energy problems before 2100. Wouldn't it make sense to allocate research and development resources to something that we know works?

The talk is always about break-even with fusion (3, Interesting)

circletimessquare (444983) | more than 2 years ago | (#39440839)

But about capturing the power? Are we generating heat that will drive steam turbines?

What schemes to capture and harness the power exist?

Re:The talk is always about break-even with fusion (1)

benjfowler (239527) | more than 2 years ago | (#39440913)

A tokamak power plant would use a thick wall, called a blanket, which slows the fast neutrons from the reaction, and using the resulting heat to heat a working fluid, driving a turbine. Note that this hasn't been demonstrated yet though -- they'll do this on ITER.

Re:The talk is always about break-even with fusion (2)

majanz (2601225) | more than 2 years ago | (#39441351)

So it'll just be like Fission, Gas or Coal? Provide a heat source to boil water to drive a turbine? How's that going to power my starship? Is there anyway to use something like an MHD generator ( to convert the fusion plasma directly into energy?

Re:The talk is always about break-even with fusion (1)

tp1024 (2409684) | more than 2 years ago | (#39441405)

JET almost broke even in 1997 - they got Q=0.7. Theoretically, they could achieve Q=1, but what's the point in that? The turbine has an efficiency of about 33% (give or take), so you'd need Q=3 just for steady state operation without further losses. Economical power generation will need more than this, on the order of q=20. However it's not as bad as it sounds. The plan is to try to achieve plasma ignition at ITER (which is Q hitting infinity - the fusion reaction sustaining itself, needing no outside heating, just magnetic confinement). So, it's not a linear scale at all.

Dense Plasma Focus (5, Interesting)

mbradmoody (732860) | more than 2 years ago | (#39440849)

Do you see any merit in the "dense plasma focus" approach to commercial fusion power production, specifically the work of the Lawrenceville Plasma Physics group?

Re:Dense Plasma Focus (4, Interesting)

Dr_Barnowl (709838) | more than 2 years ago | (#39441213)

I would mod up, but I have already commented.

Their reactor design is certainly the most elegant, being the only device I've seen that proposes collecting the energy in a solid-state manner, and not just boiling a damn great kettle like everything else. It's also one of the smaller scale devices, the design reactor fitting in a shipping container and projected to cost on the order of a million dollars rather than being in the billions, producing on the order of 5 MW, making it a shoe-in for military funding to prime the development pump (the military would go ape for something the size of a shipping container that can produce 5 MW without having to ship in diesel fuel).

It doesn't require rare and expensive tritium fuel. If their project manages to prove over-unity it would also seem to have the fewest engineer hurdles to becoming a commercial product, the difficulties mostly surrounding the construction of really fast high power switches, and an X-photoelectric collector.

Their operating budget is tiny compared to the likes of NIF and ITER as well ; it would be great to see even a few percent of these budgets distributed to alternative approaches.

Fusion Milestone Prizes (4, Informative)

Baldrson (78598) | more than 2 years ago | (#39440887)

In 1992, with the assistance of fusion technologists such as Robert W. Bussard, I developed legislative language for a series of 12 milestones, each of which would be awarded a $(1992)100M prize for the achievement of objectives toward the attainment of practical fusion energy [] . This legislation also provided a grace period during which scientists and technologists that had been working on the US fusion program would be provided full salaries, without obligation, during which time they could seek support for their ideas to achieve these milestones. This legislation presaged a number of other prizes including the X-Prize and BAFAR [] /CATS prize [] .

In 1995, Robert W. Bussard submitted this legislation to all relevant Congressional committees, copying all US plasma physics laboratories.

Needless to say, the legislation wasn't passed.

Do you think the time is right?

Scaling of Tokamaks (1, Interesting)

tp1024 (2409684) | more than 2 years ago | (#39440907)

I haven't really found a concise statement on this so far. Assuming the current state of the art in plasma dynamics, how do fusion reactors scale with respect to size and magnetic field strength? Both in terms of the Q value of D-T reactions and D-D reactions. So, what happens when you scale up the size or magnetic field strength by a factor of 2?

(What Q values have been achieved with D-D fusion anyway? I've seen 0.7 for JET in a real-world D-T trial in 1997. What's typical fori D-D? How much effort does it take to get D-D to the current level of D-T?)

LPP (0)

Anonymous Coward | more than 2 years ago | (#39440923)

Do the guys at have a real chance of achiving their goals? They seem pretty confident but do they have merits to be so? if so, why can't the goberment just fork 100mil to them?

Your take on Rossi Cold Fusion? (0)

Anonymous Coward | more than 2 years ago | (#39440961)

I was wondering if I could get an expert opinion on the latest cold fusion fad going around:

Is it just bunk or is there more to it? Thanks in advance!

ITER (2)

MpVpRb (1423381) | more than 2 years ago | (#39441033)

Is the ITER project good science?

Or, is it a politically motivated, pork laden boondoggle?

Infighting by fusion researchers? (1, Interesting)

Medievalist (16032) | more than 2 years ago | (#39441039)

Researchers studying different types of reactors (Bussard polywells, tokamaks, LENR like the Rossi eCat, Farnsworth fusors, etc.) seem to spend an inordinate amount of time making negative public statements about each others' work.

Are there any researchers outside your own field that have attacked your work? Do you see this as a problem? Is it an unavoidable consequence of trying to gain funding when fission is the favored technology? Does all non-fission research suffer when fusion researchers fight among themselves, or is this just part of the normal scientific debate?

A solution to a lot of problems (1)

boddhisatva (774894) | more than 2 years ago | (#39441051)

A safe, clean, reliable, inexpensive source of energy many orders of magnitude greater than anything we have is (or could be) a solution to many of our problems, economic and environmental. Lowering costs of everything means, well, a lot. Better world standard of living, health care, food goes on. The future of manned space exploration depends on this. Without a new, very powerful source of energy, we aren't going anywhere. Is fusion the answer? Is it the answer? Is it at least a step in the right direction?


Anonymous Coward | more than 2 years ago | (#39441053)

Suffering *BSD []

NIF (3, Interesting)

Grond (15515) | more than 2 years ago | (#39441059)

Is the NIF approach even plausibly capable of generating electricity in a useful way, or is it purely a research platform / smokescreen for nuclear weapons research?

How the heat would be transfered? (0)

Anonymous Coward | more than 2 years ago | (#39441081)

As so far as I know fusion experiments have sought to make fusion happen but not to harvest the energy. Obviously for a workable system, one would need to be able to harvest this energy. How could that be done at all? In Nuclear power plant, the water is directly in contact with the uranium/plutonium but that is obviously not an option here. How could the heat transfer be done?

Helium3 ? (1)

tekrat (242117) | more than 2 years ago | (#39441099)

I've always heard that fusion was very, very difficult without Helium3, which is in short supply Earth-wise, but more available on the moon.

How is your process dealing with the Helium3 issue (if at all), and how did you overcome the difficulties involved?

Ironically, if we still had a space program, we'd probably have had fusion since the mid-80's since we'd be mining all that Helium3....

Hes3 is the decay product of Tritium, no shortages (2)

tp1024 (2409684) | more than 2 years ago | (#39441277)

Sorry to tell you, but the whole He-3 story is a bunch of crap.Neither is He-3 rare, as it is absolutely no problem to make Tritium out of Lithium - you just need to wait 11 years for half the tritium to turn into He-3.

That said, D-He-3 fusion is as hard to achieve as D-D and certainly much harder than D-T fusion. Worse yet, in D-He3 fusion there is a parasitic D-D fusion process that is actually favoured (by nature) over D-He-3. The whole thing is just irrelevant and a huge strawman.

Patent issues? (1)

reovirus1 (722769) | more than 2 years ago | (#39441173)

Do you find yourself hamstrung by patent issues? Are there approaches you would like to take that are just not worth pursuing because existing patents would get in the way?

Ignoring all questions of *can* they work... (2)

Rei (128717) | more than 2 years ago | (#39441183)

and even ignoring all questions of whether they can generate net useful, saleable electricity... how likely do you feel that descendants of tokamaks like ITER are to produce economically viable electricity (including capital cost amortization), given their large scaling requirements, and on what sort of timeframe? What about inertial confinement alternatives based on the HiPER [] approach? As an ousider, it seems to me that the HiPER concept can be scaled down much more, and hence looks more attractive as a generation method.

Your Favorite Books? (3, Interesting)

eldavojohn (898314) | more than 2 years ago | (#39441185)

So I'm not a physicist (software guy) but I've taken a few physics classes. At an early age I found a tattered copy of George Gamow's One Two Three . . . Infinity [] which, although incorrect in some parts (I guess that's why they revised it and that's why 'speculations' was in the title), was perfectly written for my then fifth grade mind. It set me on a path toward science and a few weeks ago I saw the same 1960s Viking Press edition and flipped through it noticing what was slightly off and remembering it. I've since grown to love other obvious books like Hawking, Penrose, Hofstadter, etc.

So, quite simply, what are your favorite books for all minds young and old? Also, can you annotate which are written for the layman's entry into the given field and which are written to encompass the field for the researcher? I find that some books start off with the jargon so strong and the references and footnotes so thick that you start to have to reread every paragraph as they're clearly condensing entire historic papers into lengthy sentences. Any fiction books worthy of influencing your work and desires?

Ranking different fusion concepts (3, Interesting)

Anonymous Coward | more than 2 years ago | (#39441187)

There are many potential routes to economic fusion. Assuming each of these concepts were funded at ITER levels, how would you rank the potential for economic fusion (cost competitive with nuclear) coming from each of the following concepts within the next 25-30 years:
1/ Field Reversed Configuration - eg Helion Energy, Tri Alpha
2/ Electrostatic Confinement - eg Polywell/EMC2
3/ Magnetised Target Fusion - eg General Fusion
4/ Laser Inertial Confinement - eg NIF, HiPER
5/ Heavy Ion Inertial Confinement - eg Fusion Power Corporation
6/ Tokamaks - eg ITER, DEMO
7/ Stellarator - eg Wendelstein 7-X
8/ Levitated Dipole - eg MIT LDX

How do Tokamaks scale with size/field/etc.? (0)

Anonymous Coward | more than 2 years ago | (#39441191)

I mean, how does the physical size of the reactor influence how hard/easy it is to achieve breakeven fusion power? I imagine there is some minimum size that one needs to have in order for the fusion to produce more heat than escapes the reactor. If you'd double the size of iter size of ITER (8 times the reactor volume), how much more fusion power it could produce?
How about magnetic field - for example - if there were superconductors available that could support, say 20% stronger magnetic field than currently used ones, how much more power would one get?

DPF and Polywell (0)

Anonymous Coward | more than 2 years ago | (#39441197)

Both the Dense Plasma Focus and thr Polywell seem like novel approaches to break even fusion compared to much larger and much more expensive programs. I was wondering if you could give me your take on these technologies currently being researched, I'm particularly interested in Lawrenceville Plasma Physics' DPF research @

Logistical Simulation Determination? (1)

LifesABeach (234436) | more than 2 years ago | (#39441199)

I figure everyone that is actively working on this project has an overall understanding as to what needs to be done before their part of the project "kicks in." But what of Logistics? Consider that glory of glories, tomorrow, it works. Someone is going to eventually call up and ask the question, "Great work team! But where do I plug in?"

I figure, right about now, that in the back of the room that holds the team meeting for this project, 3 or 4 Engineering Gieniuses are vapor locking.

Where do you see the answers to the questions? (1)

MarkvW (1037596) | more than 2 years ago | (#39441225)

Where are the answers posted?

Fusion fuel. (1)

tragedy (27079) | more than 2 years ago | (#39441253)

Achieving break-even fusion seems like it has to be an eventually achievable goal. After all, stars show us that it's just a matter of scale in the end and it's been achieved non-sustainably with fusion bombs (some have argued that sustainable fusion power is achievable now by detonating fusion bombs in giant underground chambers). The question I have is, once we have sustainable fusion reactors, are they really viable as a general-use power source? The reason I wonder is because, unlike stars which run on plain-old single proton hydrogen, most sustainable fusion reactors seem to require tritium or other reasonably exotic isotopes. There aren't really any natural processes that concentrate tritium that I'm aware of, so we either need to concentrate it or make it ourselves through other nuclear reactions. That's fine for experimental reactors, military applications, space missions, etc. where it doesn't matter if the fuel costs more per unit of output energy than other power generation methods. The question is whether the fuel can be supplied in a way that is economic and sustainable for regular power generation. Has anyone done any work on what a future fuel supply chain for fusion power would look like?

Don't get me wrong, even if fusion power will never be viable versus say solar power (which is, after all, just a way of capturing the output of a natural fusion reactor), I still think that it's worthwhile developing it simply for the increased understanding we'll gain, let alone the applications in space and other endeavours where fuel cost is not the primary concern. I'm just wondering if we'll end up with the situation where we have workable fusion reactors, but fuelling them economically will be the next advance that will continuously be 20 years away. Also I wonder if they will be another power source that looks good on paper until you consider the externalities. You know the sort of thing: marvellously clean and cheap reactor fuelled by a chain of very dirty and expensive mining and fuel processing operations.

Obviously there are a number of potential fuels for fusion and some are cheaper and easier to get than tritium. In an ideal world, we would be able to use regular hydrogen in which case we're swimming in fuel. Back of the envelope calculations suggest that, even if we could replicate the conditions of the core of the sun, a reactor that could power the city of New York running on regular hydrogen fuel would need to mass many times more than the entire city, so it seems like we'd need to develop some truly amazing fusion technology to use regular hydrogen for fusion fuel.

Extracting the heat (2)

onyxruby (118189) | more than 2 years ago | (#39441257)

How do you extract the heat once you are successful in fusion? Is there a safe zone where it is just right to run water to convert to steam? With fusion running so hot and containment being such an issue it makes me think that extracting the energy could also be a fair challenge.

If you could have anything you wanted... (3, Interesting)

reovirus1 (722769) | more than 2 years ago | (#39441269)

If the president came to you and said, "We have a national emergency. We need this to become a viable form of energy as soon as possible. You have the entire resources of the nation available. I will use my executive powers to make it happen. Whatever resources, funding and people you need..." What kinds of things would you ask for? How long with the entire backing of a nation and the political will to make it happen would it take?

Focus Fusion / aneutronic fusion (5, Interesting)

mwk88 (633079) | more than 2 years ago | (#39441275)

Focus Fusion Society [] is posting research on their project to do aneutronic e.g. Proton Boron (pB11) fusion. The concept sounds great, and as an engineer several parts of their design such as direct extraction of electric power are elegant. Is this credible research or pie-in-the-sky? I have not seen much mention in mainstream fusion research.

The Saint (1)

Iniamyen (2440798) | more than 2 years ago | (#39441333)

My wife wants to know if any of you guys look like Val Kilmer.

They've spent billions on a dead end solution! (2)

Paracelcus (151056) | more than 2 years ago | (#39441369)

Making fusion power with a massive laser and a tiny bit of deuterium, is what's holding them back, it's rediculous! How about speeding a matter stream of deuterium atoms around a toroid, in a vacuum using superconductive "pinch points" around the circumference? it would set up tiny shockwaves of very high temperature and pressure. As the system is refined the matter stream could become self propelling, sacrificing only a very small percentage of deuterium atoms per cycle. And the potential power generation could be accomplished not through heat, but by using the spinning matter stream as the armature (rotating center) of a generator/alternator.


Relative price (1)

chebucto (992517) | more than 2 years ago | (#39441413)

Do you have an estimate for how much fusion will cost per kWh relative to today's technologies, like fission, coal, and natural gas?

I'm interested in knowing whether fusion will bring down the cost of electricity. A pet idea of mine for some time has been that commercial fusion power could bring down the cost of desalination enough that access to fresh water will no longer be a problem for countries that can afford to build the infrastructure in the first place.

Plasma Control at NIF (1)

Scottingham (2036128) | more than 2 years ago | (#39441433)

nuclear-fusion-simulation-high-gain-energy []

How likely is this approach to pan out in testing? It seems to me that plasma control would be paramount to success. I've read elsewhere that there have been advances is plasma control for tokamak reactors using supercomputers. Could these advances also be applied to this technique?


Proving it impossible (1)

Anonymous Coward | more than 2 years ago | (#39441467)

What would it take to prove it cannot be done in controlled and sustainable manner?

We're talking about a process that's currently only ``controlled'' at the center of the sun---with amazing pressures generated by the huge gravity well... is still manages to spew out huge amounts of harmful radiation in all directions. What makes us think that any materials we create on earth could contain a reaction that takes an entire star to control.

(yes, playing devil's advocate; would love to see controlled fusion materialize sometime in the near future---just have doubts about feasibility of the thing).

mod UP (-1)

Anonymous Coward | more than 2 years ago | (#39441489)

Romeo and Juliet T4lk to one of the

General Fusion approach? (2)

yyzmcleod (1534129) | more than 2 years ago | (#39441535)

What is your opinion of General Fusion's ( approach to a fusion reactor design?
Load More Comments
Slashdot Login

Need an Account?

Forgot your password?