Beta
×

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!

New 'Stellarator' Design for Fusion Reactors

Zonk posted about 7 years ago | from the less-whoosh-boom-for-your-money dept.

Power 171

eldavojohn writes "The holy grail of fusion reactors has always seemed 'just a few years off' for many decades. But a recent design enhancement termed a 'Stellarator' may change all that. The point at which a fusion reactor crashes is when particles begin escaping due to disruptions in the plasma. A NYU team has discovered that coiling specific wires to form a magnetic field may contain the plasma. This may be a a viable way to create a plasma body with axial symmetry, and a far better chance of remaining stable. Like other forms of containment this does require energy itself, but could bring us closer to a stable fusion reactor. It may not be cold fusion or 'table top' fusion but it certainly is a step forward. The paper is up for peer review in the Proceedings of the National Academy of Sciences."

cancel ×

171 comments

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

Princeton 1951 called... (2, Insightful)

Anonymous Coward | about 7 years ago | (#20190041)

...they want credit.

STELLLLAAAAA! (0)

Anonymous Coward | about 7 years ago | (#20192257)

SSTTTEEEEELLLLLLAAAAAAA!

If they used... (3, Funny)

jd (1658) | about 7 years ago | (#20190079)

...Axl symmetry, they could produce something that was violently unstable but produced vast amounts of marketable energy and money.

Re:If they used... (1, Insightful)

Anonymous Coward | about 7 years ago | (#20190369)

The whole thing is a huge CON and a case of lifetime 'jobs for the boys' - a bunch of overblown assholes who aren't remotely interested in finding a CHEAP energy source - they want a CENTRALISED energy source that a government can completely control.

We already can get ALL the energy we need from renewable sources - ITER and its ilk are just money pits, and guess who pays for this bullshit? The PUBLIC.

It's always "It'll be ready in 50 years' time". i.e. in 50 years' time, they'll STILL be saying "It'll be ready in 50 years' time".

Re:If they used... (3, Funny)

heinousjay (683506) | about 7 years ago | (#20190755)

I hope you're serious, I take great solace in knowing the world is full of crazy people.

Re:If they used... (2, Interesting)

jd (1658) | about 7 years ago | (#20191569)

I don't - they keep getting elected. What we don't need right now is more crazies in power. What we need is someone so totally and utterly insane, they'll spend two or three trillion dollars a year on getting a full-scale fusion reactor built and operational before they get kicked out of office or shot. Yes, there are many unsolved problems, but we're running a little low on time and researchers are too busy on corner cases that might never happen in a real reactor under normal conditions. Building a live system and requiring the scientists to live within blast radius would likely get faster results and just as much reliability.

Re:If they used... (1)

Dachannien (617929) | about 7 years ago | (#20192441)

If they used Axel symmetry, it would fight crime, too.

what took so long? (1)

ILuvRamen (1026668) | about 7 years ago | (#20190127)

Haven't they used gigantic super magnets to contain (and accelerate) particles on particle accelerators for like...ever? Probably at least 10 years. I mean really, why did it take so long to figure out that that was a good way to keep particles in?

From the No-Sheet-Sherlock Dept... (0)

Anonymous Coward | about 7 years ago | (#20191209)

After the magnetic field inside the boundary of a physically desirable plasma has been optimized, we determine the number, shape, and position of coils that are required to generate the external field, the scientists wrote
Good, now we can get back to the easy task of optimizing the field...

From the chasing your own tail dept. (3, Insightful)

Lord Balto (973273) | about 7 years ago | (#20192083)

For the $1,000,000,000,000 Monkey Boy will spend in Iraq we could have put solar collectors on every home in America for free. So they finally figure out how to make fusion work. Energy will still be monopolized by the power companies and you'll still be paying through the nose. And if you try to do anything about it they'll call you an enemy combatant and send you to Guantanamo. There is no technological fix. There is only a political fix.

Stellarators aren't new (4, Informative)

Anonymous Coward | about 7 years ago | (#20190141)

The summary makes it sound like stellarators are something novel, which they are not. Research has been going on for decades, most notably with the German Wendelstein experimental reactors.

Re:Stellarators aren't new (5, Informative)

iamlucky13 (795185) | about 7 years ago | (#20190853)

In fact, the stellarator design is almost as old as the Tokamak design. The first one was built in 1951.

Somebody over at physorg got a little too excited about a fairly low-impact paper from NYU. If you read the abstract, you'll see that the paper just deals with the design of the coils for a stellarator.

Most likely, this is for the National Compact Stellarator Experiment (NCSX) being built at nearby Princeton, which will be the first stellarator designed with a computer optimized plasma geometry. I think it will also be the largest stellarator to date, with 12 MW of heating capacity. In contrast, the JET Tokamak has 37 MW and the ITER Tokamak will have 110 MW of heating. Unlike ITER, NCSX will not be capable of break-even operation.

Stellarators often get mentioned in fusion power discussions because they provide a more stable containment design, whereas a Tokamak needs one extra set of electromagnets to deal with the fact that the magnetic field is weaker at the outside of a torus of magnets than at the inside. Although a stellarator is therefore a little simpler in that regard, the geometry and plasma modelling is much more complex, and this in turn creates problems for designing the coils and the exhaust diverter. Because of this, most of the funding and research effort has gone to the Tokamaks.

A little more info here: http://en.wikipedia.org/wiki/Stellarator [wikipedia.org]

Anybody care to bet on whether this shows up on CNN's tech page in a day or two as some major "recent design enhancement?"

input-output (2)

polar red (215081) | about 7 years ago | (#20190145)

Like other forms of containment this does require energy itself
I find it weird that the amount of energy needed to contain, is less than the energy contained in the plasma. Can anyone explain this ?

Re:input-output (4, Insightful)

Paul Pierce (739303) | about 7 years ago | (#20190251)

Like other forms of containment this does require energy itself
I find it weird that the amount of energy needed to contain, is less than the energy contained in the plasma. Can anyone explain this ?

Picture Chinese handcuffs

Re:input-output (4, Funny)

feepness (543479) | about 7 years ago | (#20190575)

Picture Chinese handcuffs
Great now I can't let go of that image.

Re:input-output (0)

Anonymous Coward | about 7 years ago | (#20191301)

I can help picture Two Gay Men playing with Chinese Handcuffs :-p

Re:input-output (2, Interesting)

thanatos_x (1086171) | about 7 years ago | (#20190791)

It's intrinsically harder to do useful work that raw work, just like it's easier to destroy than create....

It could also be that it's a brute force attempt to force cohesion, and since force must be met with equal force it's very difficult. That also assumes it could concentrate the exact amount of energy at exactly the right point. Just imagine trying to not only stop a terrorist attack, but subdue them without lethal force. They need one leak to win. You need a perfect record.

Re:input-output (1, Insightful)

Anonymous Coward | about 7 years ago | (#20191651)

just like it's easier to destroy than create...

Actually, at a fundamental physical level, that's untrue. The only thing that costs energy is erasure of information.

Re:input-output (5, Informative)

iamlucky13 (795185) | about 7 years ago | (#20191035)

Well, I'm not a plasma physicist, so I'm not intimately familiar with all the details, but one thing that jumps out at me right away is the distinction between energy and power.

Energy is the ability to do work. Power is the rate at which work is done or energy is extracted.

The plasma contains a great amount of thermal energy with a tendency to do work (by difussing to the reactor walls), so you have to set up a barrier to accomplishing that work. This is analogous to a dam holding back water. The water, due to it's elevation, has a lot of potential energy, but no power is required to hold it back. Power is extracted as it's let through the turbines.

It's a little more complicated for a plasma. A charged particle moving through a varying magnetic field (like that surrounding the reactor) does work and thereby loses energy. As a result, there is a tendency, although less definite than with a dam and water, for the hydrogen ions to only move around in the reactor along lines of constant magnetic field strength.

Once a magnetic field is established, it ideally takes no energy to maintain, except as charged particles move through it. So power only has to be supplied to the electromagnets to account for their inefficiency (0 under ideal conditions in a superconducting Tokamak) or as work is done on the field by charged particles escaping. Since most of the energy from the reactions is carried away by neutrons, which have no electric charge and therefore don't affect the field, the containment power is sufficiently smaller than the reaction power that this is theoretically feasible as a power plant.

Actually, the biggest power demand in a Tokamak as I understand is for heating the plasma to a temperature where fusion will take place. The hotter it gets, the faster fusion occurs, eventually reaching a breakeven point energy is released by fusion faster than it is carried away by escaping neutrons and gamma rays. Then the plasma can sustain itself. We haven't gotten there yet.

Sorry, the dam analogy isn't great and talking about charged particles in a magnetic field is a little abstract. Hope this helps.

Magnetic fields do no work (1)

supergumby (141149) | about 7 years ago | (#20191337)

While a varying magnetic field can do work on a charged particle, magnetic confinement fusion systems use static magnetic fields. A static magnetic field does not do work on a charged particle.

Also, the particles move to the position of lowest potential energy, not necessarily along lines of constant field strength.

Good summary otherwise.

Re:input-output (1)

mako1138 (837520) | about 7 years ago | (#20192037)

Actually, the biggest power demand in a Tokamak as I understand is for heating the plasma to a temperature where fusion will take place. The hotter it gets, the faster fusion occurs, eventually reaching a breakeven point energy is released by fusion faster than it is carried away by escaping neutrons and gamma rays. Then the plasma can sustain itself. We haven't gotten there yet.
Some subtleties:

Fusion reaction rates are proportional to temperature, but only up to a certain point. The trend is roughly parabolic.

'Breakeven' is usually calculated on the assumption that energy leaving the plasma is reinjected with a certain efficiency, typically 1/3. 'Ignition' is when the fusion reaction can go on without any external power input.

Also, I realize it's a rough analogy, but the dam picture is inadequate. My professor described fusion confinement as "trying to hold jell-o with string".

Re:input-output (5, Informative)

counterfriction (934292) | about 7 years ago | (#20191067)

"Energy" in the context of containing a plasma is actually work. They have the same units, so they're like exchangeable currencies (i.e. some energy will buy you work, and some negative work will buy you energy)
The energy that a plasma intrinsically has (like kinetic energy) is just that; energy.

Here's a related (but certainly not airtight) analogy: A brick can have some gravitational potential energy relative to the earth's surface. If you're standing on the ground, that brick will have some nominal gravitational potential energy. If you lift that brick 1 meter, you'll do some amount of work. If you're hanging over the edge of a helicopter at a couple hundred meters, that brick has substantially higher gravitational potential energy. However, if you lift the brick a distance of 1 meter, you'll still do the same amount of work.

So, what's going on here is that a plasma can indeed have a lot of energy (relative to the earth's environment). However, the "energy" we're putting in is actually work to contain that plasma.

Huh... (2, Funny)

Greyfox (87712) | about 7 years ago | (#20190163)

SCO Loses and they figure out fusion* on the same day. Coincidence? I think NOT!

* Sure it doesn't say they figured it out in TFA but humanity will point to this day and say 'That is the day SCO lost and they figured out fusion.'

to clarify (1)

spune (715782) | about 7 years ago | (#20190209)

It is the improved stellarator design that is new; stellarators have been around for decades.

Thorium reactors (4, Interesting)

Bombula (670389) | about 7 years ago | (#20190237)

I was reading about thorium reactors recently. Seems like that's much closer to being rolled out, and its developers are claiming it solves a lot of the problems with existing reactors: it's more stable because thorium reactions don't chain the same way, it doesn't produce waste or plutonium, it can actually burn up other waste - including plutonium, and it can be used in some types of existing reactors (there are trials in Russian reactors right now).

Does anyone know any more about this?

Re:Thorium reactors (1)

meringuoid (568297) | about 7 years ago | (#20191083)

Thorium good, but if possible, fusion even better.

If you want to see thorium-fuelled fission reactors in operation, you'll probably want to go to India. They're sitting on about a quarter of the world's thorium supply, and quite reasonably think that they ought to get some use out of the stuff.

Re:Thorium reactors (3, Interesting)

Bombula (670389) | about 7 years ago | (#20191269)

Thorium good, but if possible, fusion even better.

It's important to define 'better' here. Cost would seem to be an important consideration, for example. I don't know what the price tag of fusion is so far, but it's awfully, awfully high already and without a great deal to show for it. If we've already got a pretty good thing in thorium, and we already have the reactors, and there's enough thorium and uranium to keep us in electricity at present consumption rates for thousands of years, and it's non-polluting and all the rest, then how is fusion - a hugely expensive, so far unproductive technology - 'even better'. I'm not quibbling or trying to be antagonistic here - it's a serious question, and it needs a serious answer considering what's at stake: we need clean, non-polluting power that doesn't ultimately come from politically volatile parts of the world.

Re:Thorium reactors (3, Informative)

mdsolar (1045926) | about 7 years ago | (#20192513)

Solar and wind power fit the bill of being clean and local. A lot of our nuclear fuel these days comes from Russian weapons stockpiles. But the process of diluting it back down from weapons grade to fuel grade is not going all that well. In an accident in Tennessee last year that was covered up until congress stepped in, the plant managers thought that a big spill of highly enriched uranium soulution, enough to cause the kind of accident that killed 2 people in Japan 1999, was natural uranium. There were two places where the spill might have accumulated and cause criticality. That is pretty poor materials control if you don't know what it is that you are working with.

Uranium reserves are estimated to be about 85 years at present use. Plans to extend the life of nuclear power all pretty much include breeder reactors (such as thorium reactors) and have unresolved fuel cycle problems. Fast breeder reactors are also illegal in the US owing to proliferation concerns. Their prototypes have also tended to melt down.

The new reactor being planned for Calvert Cliffs has an estimated price tag of $2.50/Watt for construction alone, though with federal loan guarranties included in the Senate Energy Bill, this price will likely rise substantially. The price compares poorly with wind and solar, both at about $1.30/watt to build, but with much less in the way of operating costs, and obviously no fuel or long term waste disposal costs.

The level of effort put into fusion has not really been that large. You hear about it, but compared to the Manhatten Project, out of which nuclear power came, it gets much less in the way of GDP. Renewables get even less than that. This was deliberate. The idea was to give it enough effort so that it would be ready when oil and coal ran out. The problem is that at the time, the growth in the use of coal and oil was not foreseen. So, fusion is actually right about on schedule. When it is here, there may be some trouble siting it since nuclear power plants squat on some of the better cooling resources and our storage in place policy for nuclear waste may keep these prime resources tied up for hundreds of years. But, wind was 20% of new generation in 2006 and is growing at 50% per year, while solar is growing at 30% per year and this should accelerate as the silicon purification bottleneck clears. So, fusion may enter a market that is already dominated by clean inexpensive power and thus find only niche applications in any case.
--
Go solar the easy way: http://mdsolar.blogspot.com/2007/01/slashdot-users -selling-solar.html [blogspot.com]

Re:Thorium reactors (1)

quanticle (843097) | about 7 years ago | (#20192715)

The problem with thorium, as with all nuclear fission, is that eventually you'll still get waste that's unusable for energy production, but still emitting enough radiation to be dangerous. As the waste sits in this phase for quite a time (I've heard spans on the order of centuries) you have to find landfill locations that are stable enough to hold spent fuel for extremely long spans of time. Its the lack of space to store waste, rather than lack of fuel that's the limiting factor with nuclear fission.

With fusion, though, all outputs are stable; therefore waste isn't a concern.

Re:Thorium reactors (2, Informative)

barawn (25691) | about 7 years ago | (#20192821)

That's not exactly true. The ideal output of most fusion cycles is stable. You get side production of tritium and a few other radioactive isotopes, though.

But fusion does, however, produce a large amount of radioactive waste. Not through the products of the reaction. Through the byproducts of the high level of irradiation.

The difference is that fission radioactive byproducts are long lived. Fusion radioactive byproducts are extremely radioactive, but very short lived, and therefore easier to deal with

Re:Thorium reactors (2, Informative)

Your.Master (1088569) | about 7 years ago | (#20192895)

Advantages of Fusion:

* Fuel for fusion can be extracted from water, including non-potable water. Fission requires Uranium & Thorium to be mined and transported, and your country might not have it. By the time the fuel runs out, our sun will be a red giant, so we should worry about escaping the solar system before doing any better than that.
* No weapons material generation (Thorium is in some respects similar here).
* Radioactive waste: there's a lot less of the stuff sticking around, and really no high-level waste at all. This can save a lot of money with disposal and some with safety equipment, not to mention avoiding the headaches of dealing with people who believe that radioactive waste should not be produced at any cost. Note that this is actually partly a problem, since many nuclear "waste" materials have important industrial and medical uses, so we will likely continue to run some of these fission reactors anyway (or perhaps figure out ways to produce these radioactive isotopes more directly).
* Although fission plants are perfectly safe, there are a lot of people who still fear them for a variety of reasons, mentioning any of which is likely to lead to a fruitless and flame filled side-discussion if anybody reads my post at all. Fusion power is inherently even safer, which might satisfy a few of these people.

Re:Thorium reactors (1)

mdsolar (1045926) | about 7 years ago | (#20191381)

You want to be careful with that stuff. There was a boy who built a breeder in his mother's shed in the ninties using thorium. He was arrested again at the beginning of this month for stealing smoke detectors. He does not look so healthy in his mugshot: http://freep.com/apps/pbcs.dll/article?AID=/200708 03/NEWS04/70803062 [freep.com] . Sad story. There just isn't any such thing as clean fission. It makes a mess every time.
--
Get clean energy: http://mdsolar.blogspot.com/2007/01/slashdot-users -selling-solar.html [blogspot.com]

Re:Thorium reactors (1)

Hoi Polloi (522990) | about 7 years ago | (#20191983)

Yow, what happened to his face? I think he should be stealing chemotherapy drugs instead of smoke detectors. I guess once you've made one reactor you just can't quit.

Oh, great! (4, Funny)

Sloppy (14984) | about 7 years ago | (#20190297)

I just bought a fusion reactor that uses the old design!

Re:Oh, great! (-1, Redundant)

Anonymous Coward | about 7 years ago | (#20190667)

And you just bought an iMac as well!!!

Re:Oh, great! (1)

magus_melchior (262681) | about 7 years ago | (#20191499)

"'Best before November 1959.' Damn it, Bob, there were plenty of brand-new bombs, but you had to go for that retro 50's charm."

I'm Sorry (1)

JamesRose (1062530) | about 7 years ago | (#20190365)

But Some Rapscallion has slipped an extra cyllable into the name of your system!

Stellarator? Its somehow wrong

Stellarators have been around as an idea for years (4, Insightful)

Zarhan (415465) | about 7 years ago | (#20190391)

...and as prototypes too.

http://en.wikipedia.org/wiki/Stellarator [wikipedia.org]

Anyway, basically what I know about this is that stellarator designs avoids lots of the problems that are present in Tokamak - namely, degrading of the reaction chamber due to escaped neutrons. A fusion reactor using stellarator instead of Tokamak would, in effect, last forever since the material does not become radioactive.

Especially the Germans have been researching this stuff a lot, however, most of the big money is currently in Tokamak designs, including ITER. Which is kinda a shame - since we're not in the Manhattan Project-type "if you have 3 designs and think one of them might work, build all three, here's the money"-situation..so these nice ideas may only be developed further if Tokamak fails to become viable..

Re:Stellarators have been around as an idea for ye (1)

Grishnakh (216268) | about 7 years ago | (#20190423)

According to the comments at the end of the physorg article, that's not true.

Also according to those comments, the idea of fusing atoms is completely unproven.

I think I'm just going to give up on humanity.

Re:Stellarators have been around as an idea for ye (1)

FleaPlus (6935) | about 7 years ago | (#20190805)

Right. The slashdot summary is faulty: What's new isn't the stellerator design itself, but a new coil configuration for a stellerator. The new configuration "generating an external magnetic field designed to prevent the plasma from deteriorating", although I'm not familiar enough with stellerators to know how much of a problem this was in previous designs.

Re:Stellarators have been around as an idea for ye (1)

DerekLyons (302214) | about 7 years ago | (#20191235)

Anyway, basically what I know about this is that stellarator designs avoids lots of the problems that are present in Tokamak - namely, degrading of the reaction chamber due to escaped neutrons.

So, where in the stellerator design does the unobtanium shielding goes that stops the neutrons?
 
This is a serious question. If you have [hot] fusion you have neutrons, and they have to go somewhere. Magnetic fields won't stop them.

Re:Stellarators have been around as an idea for ye (1)

sanman2 (928866) | about 7 years ago | (#20191579)

NEUTRons may be NEUTRal in terms of ELECTRIC CHARGE, but as fermions they do have magnetic spin, which means they are NOT IMMUNE to the effects of a magnetic field.

Doh! (4, Informative)

the eric conspiracy (20178) | about 7 years ago | (#20190407)

A stellarator is not a new design. The first examples were built here [pppl.gov] in 1951.

Re:Doh! (0, Offtopic)

psydad (12743) | about 7 years ago | (#20191251)

To comment your sig... Nope - 12743

Re:Doh! (0, Offtopic)

the eric conspiracy (20178) | about 7 years ago | (#20191593)

My sig said 'probably', which is certainly true.

Why reinvent the wheel? (4, Interesting)

viking80 (697716) | about 7 years ago | (#20190485)

Design parameters for fusion reactor:
1. Contain a plasma ball with high density for fusion reaction. Ball is much better than doughnut if you just can figure out a way to keep the plasma together.
2. Make a wall that is far enough away to not melt from this plasma ball to absorb heat/radiation to make power, and keep it close enough to get high enough energy density on its face.
3. Make the wall 1 ton/m^2 to protect the people outside
4. Use magnetic field outside plasma ball to contain radiation.

This seems like a tall order, and it is, but consider the sun/earth:
1. Gravity works great compared to magnetism.
2. Well, here on the earth, it is 1kW/m^2. That is much higher than the energy consumption in most cities. Should be good.
3. Our atmosphere stupid.
4. The earth again has a great magnetic field that protects us pretty well.

Bottom line: Why reinvent the wheel?

Re:Why reinvent the wheel? (4, Informative)

OeLeWaPpErKe (412765) | about 7 years ago | (#20190587)

4. Use magnetic field outside plasma ball to contain radiation

This seems like the exact reason why basic physics should be mandatory in schools. Dear God. How exactly would a magnetic field contain neutral photons ? They will generate zero flux and will not interact with the field at all.

Re:Why reinvent the wheel? (0)

Anonymous Coward | about 7 years ago | (#20190843)

How exactly would a magnetic field contain neutral photons ?

It's a lot easier to understand once you realise that to some people, "magnetic" is merely a fancy way of spelling "magic".

Re:Why reinvent the wheel? (1, Funny)

Jherek Carnelian (831679) | about 7 years ago | (#20190915)

This seems like the exact reason why basic physics should be mandatory in schools. Dear God. How exactly would a magnetic field contain neutral photons ? They will generate zero flux and will not interact with the field at all.
Clearly adding a flux capacitor to the magnetic field generator is necessary to add flux to the contained photons.

Re:Why reinvent the wheel? (0)

Anonymous Coward | about 7 years ago | (#20190973)

The funny thing is, photons are the magnetic field. But yeah, photons carry no charge and do not interact with each other directly.

Re:Why reinvent the wheel? (2, Insightful)

lawpoop (604919) | about 7 years ago | (#20190981)

This seems like the exact reason why basic physics should be mandatory in schools.
Okay...

Dear God. How exactly would a magnetic field contain neutral photons ? They will generate zero flux and will not interact with the field at all.
Is this the kind of basic physics that the average student would understand in their mandatory class?

Ummm... yes? (0)

Anonymous Coward | about 7 years ago | (#20191097)

We covered that at the high school level (neutrons = no charge). What did your physics class cover?

Re:Ummm... yes? (1)

Tmack (593755) | about 7 years ago | (#20191557)

We covered that at the high school level (neutrons = no charge). What did your physics class cover?

And neutrons != photons....Though it wasnt until college Emag (Phys5 or 6 I think) that I learned all the math behind the em wave functions (yes, light IS an electro-MAGNETIC field/wave) that make all this stuff happen.

tm

Re:Why reinvent the wheel? (1)

hab136 (30884) | about 7 years ago | (#20192411)

Dear God. How exactly would a magnetic field contain neutral photons ? They will generate zero flux and will not interact with the field at all.

Is this the kind of basic physics that the average student would understand in their mandatory class?

The fact that protons are positive, electrons are negative, and neutrons are.. you know.. neutral and therefore not affected by magnetic fields.. yes, I learned that in about 6th grade.

Re:Why reinvent the wheel? (1)

Creepy Crawler (680178) | about 7 years ago | (#20192415)

If we're dealing with fusion, what are the effects of mass amounts of neutrinos going through living tissue?

You know, 1/d^2 is sort of a problem when you are d close to me. (When d is is 1/500 AU).

And yes, I do know about the super-pure H2O and Cl- deep-mine tanks that monitor for neutrinos.

Dumbass! (0)

Anonymous Coward | about 7 years ago | (#20191111)

Just reverse the polarity!

Re:Why reinvent the wheel? (1)

Aqua OS X (458522) | about 7 years ago | (#20191217)

I took physics in high school and I still have no idea what you're talking about.

Please read post before commenting (1)

viking80 (697716) | about 7 years ago | (#20191237)


4. Use magnetic field outside plasma ball to contain radiation

This seems like the exact reason why basic physics should be mandatory in schools. Dear God. How exactly would a magnetic field contain neutral photons ? They will generate zero flux and will not interact with the field at all.

Please reread parent post. Note: 1 ton/m^2 of mostly Nitrogen *and* magnetic field to protect people.
Life on earth has pretty much evolved around surviving radiation not caught by this protection. The physics is sound. 1. Atmosphere is opaque to photons with ionizing energy. 2. Neutrons are slowed down very well. 3. Charged particles are caught by magnetic field

Re:Why reinvent the wheel? (1)

qbwiz (87077) | about 7 years ago | (#20191265)

Not all radiation is made of photons. Specifically, alpha rays are made of helium nuclei (and are therefore positive) and beta rays are made of electrons (and are therefore negative).

Seems like you are flat wrong in many ways (1)

tryingagain (1140573) | about 7 years ago | (#20191319)

1. The article includes atmosphere and magnetic field as a shield. 2. Photons interact with magnetic field in many ways. -a magnetic field is just photons, and if you play with magnets, you know how these photons interacts. -both have mass, and interact gravitationally -the upper atmosphere is a plasma. There is a interaction between photons and plasma(phase/group velocity, as well as plasma and magnetic fields.

Re:Seems like you are flat wrong in many ways (1)

ConceptJunkie (24823) | about 7 years ago | (#20191485)

Photons have mass? That's news to me. I need to go back to school.

Re:Seems like you are flat wrong in many ways (1)

viking80 (697716) | about 7 years ago | (#20191575)

Photons have 0 "rest" mass, but remember:
E=mc^2 and for a photon, E=hc/l, 'l' is wavelenght and h is planck's constant, so
photon mass, m=h/(lc)

Re:Why reinvent the wheel? (1)

mdsolar (1045926) | about 7 years ago | (#20191567)

Radiation is not just photons. There is a good point here. While there are very few nuclear reactions going on on the surface of the Sun, mainly spalations from accelerated protons, there are accelerated protons from the corona (the same) that impinge on the Earth's magnetosphere and are deflected. It is the Sun's magnetic field, rather than escaping fusion products, that are responsible for the high energy particle flux.

There are also possible photon-magnetic field interactions though with a low coupling: http://www.sciam.com/article.cfm?chanID=&articleID =0006BA85-FC58-1492-BAAC83414B7F0000 [sciam.com] .
--
Get fusion on your roof:http://mdsolar.blogspot.com/2007/01/slashdot- users-selling-solar.html [blogspot.com]

Re:Why reinvent the wheel? (0)

Anonymous Coward | about 7 years ago | (#20191713)

Dear God. How exactly would a magnetic field contain neutral photons ? They will generate zero flux and will not interact with the field at all.
But it would contain all those charged neutrons. Duh.

Re:Why reinvent the wheel? (3, Funny)

Wonko the Sane (25252) | about 7 years ago | (#20190725)

3. Make the wall 1 ton/m^2 to protect the people outside

Houston, we have a unit problem

Re:Why reinvent the wheel? (1)

LinuxEagle (1123659) | about 7 years ago | (#20191077)

Errm, point me to a working fusion generator. (other then then stars and the like)... I don't think we have yet invented the wheel in this case.

Re:Why reinvent the wheel? (1)

mako1138 (837520) | about 7 years ago | (#20192157)

We're not reinventing the wheel. The sun's fusion reactions are very different from the ones envisioned for terrestrial fusion reactors.

The sun starts by fusing hydrogen. (http://www.tim-thompson.com/fusion.html)
This first step happens on a huge timescale:

p + p --> d + e+ + nu 7.9 x 10^9 years

This only works out in the sun because it's a frickin huge ball of gas.

Terrestrial reactors will use DT fusion. The time it takes for this reaction to happen is not worth talking about.

And regarding the "plasma ball with high density", consider that the typical DT fusion plasma has a density of 10^20 /m^3, which is one millionth the density of air.

In short, we can do fusion better than nature can. In 50 years (TM), that is.

Re:Why reinvent the wheel? (1)

hairykrishna (740240) | about 7 years ago | (#20192249)

Honestly, how is this insightful?

Your answer is "we should use the sun". Well done. Got any better methods than what we're using currently?

Magnetically confined plasma fusion reactors (4, Informative)

the_kanzure (1100087) | about 7 years ago | (#20190517)

Re:Magnetically confined plasma fusion reactors (1)

SchizoDuckie (1051438) | about 7 years ago | (#20190565)

I would suggest strapping on a couple of octopus clamps to your back and controlling it by hand!
At least, that's how dr. octopus did it in spiderman :P

Hurry it up, science people (0)

Anonymous Coward | about 7 years ago | (#20190609)

We're running out of petroleum faster than ever. Get cracking on this fusion thing. And what's with all the qualified statements? "Might", "may", "could": dammit, we need "can", "will", and "shall"! Where's Doctor Octopus when we need him?

somewhere over the rainbow (1)

nuzak (959558) | about 7 years ago | (#20190761)

"The holy grail of fusion reactors has always seemed 'just a few years off' for many decades. But a recent design enhancement termed a 'Stellarator' may change all that.


Practical uses of Stellarator technology are projected, of course, to be "just a few years off".

Not "up for peer review" (0)

Anonymous Coward | about 7 years ago | (#20190783)

The comment that paper is "up for peer review" makes it sound like it hasn't undergone peer review, but it has been reviewed. It will, of course, receive wider scrutiny now that it has been published...

just more big waste from big science (0)

Anonymous Coward | about 7 years ago | (#20190789)

most research funding goes directly to excessive salaries

imho, big science is largely corrupt and generally inept

Mmhmm (1)

tttonyyy (726776) | about 7 years ago | (#20190909)

Quasineutrality? Quasi-likely-to-work-in-the-real-world more like. :P

But Stella Kowalski Is The Old Style Stella (1)

NeverVotedBush (1041088) | about 7 years ago | (#20190969)

STELLLAAAAAA!!!!!

"Stellarator" (2, Funny)

flickwipe (954150) | about 7 years ago | (#20191047)

Refrigerator full of Stella?

Re:"Stellarator" (1)

SpeedyGonz (771424) | about 7 years ago | (#20191415)

Refrigerator full of Stella?

Creepy...
You sure you're not that guy that chopped his wife to pieces and left the remains in a duct-tape sealed fridge?
I know, I know, I read too much "Reuters: Oddly Enough"

Re:"Stellarator" (1)

pipingguy (566974) | about 7 years ago | (#20192631)

Stelllaaaaaa!

Nice News for Nerds but... (2, Interesting)

swokm (1140623) | about 7 years ago | (#20191179)

If society won't even accept safe fission designs, what makes you think we will ever get far more powerful fusion reactors built? I think the largest problem now is the culture of misinformation and fear, not the problem of technology.

Unless I'm wrong, the production of non-military nuclear reactor designs in the US for the last 30 years have been... zero. Unless you count the Galileo, Ulysses, and Cassini space probes. Call me when we upgrade all of our reactors from 1973 designs [wikipedia.org] to a much safer and cleaner Gen IV [wikipedia.org] design -- like this bad boy [ga.com] (now with free hydrogen!) instead of taking high-level radioactives --potential fuel-- driving them recklessly around the country in truck, and shoving it into a salt mine, or some similar brilliant idea.

Besides, though I lust for the sheer coolness of magnetically confined plasma as much as any proper geek, the the simple fact is we have had the technology to use fusion for power [wikipedia.org] for quite some time now [sandia.gov] (press release from 1998, although building the X-1 was promptly cancelled without reason) with Z-pinch inertial confinement on the insanely cool Z machine [sandia.gov] at Sandia.

Yawn. Wake me went the politics of our time aren't ruled by Luddites with pitchforks and torches...

Re:Nice News for Nerds but... (1)

mdsolar (1045926) | about 7 years ago | (#20191937)

Gen IV does not finish design for 25 years. The new reactor that is moving forward the fastest is Calvert Cliffs 3, a run-of-the-mill light water reactor. I suspect this one will have trouble. While the nuclear power industry is talking about global warming all the time now, they seem pretty foolish to be betting on a sea level reactor as their first new project since the Three Mile Island and Chernobyl disasters made clear what a problem nuclear power is. The rise in sea level is 5 cm every 15 years and the rate is doubling every 15 years, so from its current level http://www.realclimate.org/images/sealevel_2.jpg [realclimate.org] , in 45 years you get 35 cm of sea level rise, enough to make the foundations pretty soggy. That would be about halfway through the life of the plant. 90 years out you get more than 3 meters with a doubling projection. That makes a very difficult mess to clean up. Think New Orleans Lower Ninth Ward. There is more to read about this problem here: http://mdsolar.blogspot.com/2007/08/cliffhanger.ht ml [blogspot.com] , including a link to a study on proposed sea level reactors in the UK.

Re:Nice News for Nerds but... (1)

swokm (1140623) | about 7 years ago | (#20192789)

In a way, I think you restate my point, IMHO. You probably say it in a better way...

I'm not a nuclear engineer but the only info I find on Calvert Cliffs 3 is that it is still based on pre-1975 designs. That is not smart. I know Gen IV is not immediately available, but there is NO reason that we cannot start building reactors with passive fail safe technology that has been running in test IFRs for decatdes [wikipedia.org] . There is a reason everyone is moving away from light-water designs.

Why would people build in a swamp or low shoreline? No idea, I agree it sounds stupid. Although, why not run the reactor as smaller 30 year sealed design units if this HAS to be the scenario? Those, too, have existed for years. Just pull them up, service, reseal every 30 years. Nothing is simple about nuclear power, but it is not like we are not using it (or going to use it in the future). I think we should be smarter about it and use the work of the engineers from the past several decades to make better, more informed decisions -- as in site planning as you so rightly point out.

The only thing I really disagree with is:

Chernobyl disasters made clear what a problem nuclear power is
No. Chernobyl and 3Mile made clear what a problem poor design, and refusal to improve upon that design means. That is exactly where we are now, and it is why I am concerned. By sticking our heads in the sand, we are assuring that we will have a problem sooner, rather than later. Additionally, if a similarly carelessly designed and operated fusion reactor was near... say Chicago and things got out of hand there would be far more casualties, even including the lingering radioactive problems of the Ukraine.

We aren't shutting down all the nuclear reactors in the US. Period. Ain't going to happen. So why on earth aren't we doing everything we can to make them safe, or failing that rebuild them with new safer technologies ASAP? Self destructive politics. I do not think fusion will ever be a panacea for this problem.

Drop the illusions... (1)

woolio (927141) | about 7 years ago | (#20191939)

Doesn't the Z machine require vast amounts of electricity just to "fire" once? They only fire it once or twice a day at MOST and it fires for only billionths of a second. It's not a continually running thing. It also produces a shockwave something like a mini-earthquake when it fires.

Also look at this link: http://www.sandia.gov/media/z290.htm [sandia.gov]

"Stockpile stewardship" is not about solving our energy problems... Well, at least not peacefully... It's all about ensuring that the aging nukes will perform as expected on demand. A large part of Sandia is dedicated to this mission.

I believe all sorts of radiation is released when they vaporize things in the Z machine... THAT's why its useful for stockpile stewardship.

At one time, I was stupid enough to think that The Department of Energy was concerned with producing/supplying energy for the nation. Despite appearances, they seem more concerned with finding new ways of quickly releasing energy upon other nations.

Re:Drop the illusions... (1)

swokm (1140623) | about 7 years ago | (#20192875)

Doesn't the Z machine require vast amounts of electricity just to "fire" once? They only fire it once or twice a day at MOST and it fires for only billionths of a second. It's not a continually running thing. It also produces a shockwave something like a mini-earthquake when it fires.
Yes. Perhaps you missed it, but that is why I posted the link to wikipedia for Pulsed Power. This means a power cycle, much like the combustion engine in your car, where there is compression, explosion, and expansion. It is this process that eventually translates into power, by turning your car axle. This process is a little different on a large scale, but basically the same. It doesn't really matter it takes a while to charge up the capacitors for the initial fire. The only question is: 'do we capture much more power from the compression/fusion that we put into the charge?' In this case the answer is a resounding YES! We are all fortunate. I understand that you can hear it fire, again like your car engine. Is this a problem? FWIW, steam turbine generators are VERY loud, although more constant.

"Stockpile stewardship" is not about solving our energy problems... Well, at least not peacefully... It's all about ensuring that the aging nukes will perform as expected on demand. A large part of Sandia is dedicated to this mission.
Yes... I'm not sure I follow you here. It sounds like you are saying that because Sandia was originally commissioned to do testing so that the US would not have to explode live nuclear bombs on the earth's surface to see how radiation effects aging nuclear warheads, that they then are NOT allow to take use of discoveries that could use fusion to safely and peaceably generate power. Right here, right now. Sadly, this is a misunderstanding that the US government also shared, thereby canceling the new X-1 fusion power test reactor without any reason. This is a very strange and arbitrary viewpoint. Incidentally, this benefitted the existing petroleum industry that was lobbying against this reactor. I think we see how that has turned out, but I'll leave it to you to decide how much "tinfoil" is in that line of reasoning.

I believe all sorts of radiation is released when they vaporize things in the Z machine... THAT's why its useful for stockpile stewardship.
Yes... again I am confused. The only way we traditionally generate power on a large scale is harnessing SOME type of radiation, right? "Radiation" is neither BAD nor GOOD. It is like metal. It is all around us, and can be used for good or bad. It can even poison us, just like heavy metals. But really, "radiation" is just another word for power. I don't know about "all sorts" of radiation for the Z machine, but its primary purpose is to generate X-Rays, like the doctors office. Only at a much, much higher temperature. This radiation does not travel outside the building, nor is it "contagious". You don't want to sunbathe in 3 million degrees C, however.

At one time, I was stupid enough to think that The Department of Energy was concerned with producing/supplying energy for the nation. Despite appearances, they seem more concerned with finding new ways of quickly releasing energy upon other nations.
Hurray! We agree completely (see tinfoil above). This is in part why we don't want ANYBODY to build, or re-build, old dangerous FISSION reactors. If the US requires the rest of the world to only use FUSION, and we are the only country that makes FUSION reactors... well, there we are. Incidentally, if fusion ever does become practical in the US, I think all those pushing for coal, oil, and gas will suddenly sing a different tune, and wag their fingers at China, Africa, etc. "But here," they say, "I have just the thing to sell you to help you out..."

Ah, my fellow Americans... always anxious to corner the market (before there is even a market).

Re:Nice News for Nerds but... (1)

NeverVotedBush (1041088) | about 7 years ago | (#20192239)

Fusion reactors produce a whole lot less radioactive material as they run. Fission reactors make lots and lots of really hot stuff. Also, as people should take away from the article, fusion is really hard to keep going. If things get out of hand, it will just go out. No melted cores. No burning reactors dumping tons of highly radioactive material into the atmosphere and into the surrounding environment. And the whole process of refining reactor fuel does not create mega-tons of radioactive mine tailings, tons and tons of radioactive waste, and it doesn't have to be guarded because you cannot make a bomb out it (unless you already have a fission bomb to set it off).

Fusion reactors will be many many times safer than fission reactors. Hands down. I know the American public won't appreciate the above points, but if enough people explain this stuff to them, they might gradually get the upshot - fusion reactors are pretty damn safe.

University of Wisconsin HSX (0)

Anonymous Coward | about 7 years ago | (#20191197)

This monster is about 6 feet below my desk...
http://www.hsx.wisc.edu/ [wisc.edu]

Question for physicists who work on plasma (1)

zymano (581466) | about 7 years ago | (#20191541)

Why not just a sphere ????

Princeton did it first (0)

Anonymous Coward | about 7 years ago | (#20191687)

I've visited the Princeton Plasma Physics Lab, and they have one of these things in the final stages of construction
http://www.pppl.gov/polImage.cfm?doc_Id=27&size_co de=Doc [pppl.gov]
Either the NYU team did something new that's not mentioned in the article, or this is non-news

wow ... (0)

Anonymous Coward | about 7 years ago | (#20191809)

from tfa: "and to eliminate extraneous harmonics that may cause the magnetic surfaces in the plasma to deteriorate"

am i the only one here to think that sounds like a line from star trek ?

Re:wow ... (1)

DragonTHC (208439) | about 7 years ago | (#20192181)

Star Trek is REAL!

I'm gonna be Captain Kirk!

Re:wow ... (1)

toddhisattva (127032) | about 7 years ago | (#20192727)

"and to eliminate extraneous harmonics that may cause the magnetic surfaces in the plasma to deteriorate"

...overheard at a jam near Austin....

Still concave toward the plasma. (2, Interesting)

Ungrounded Lightning (62228) | about 7 years ago | (#20192379)

I seem to recall one of Bussard's points in his talk Should Google Go Nuclear? was that plasma confinement by magnetic fields is inherently unstable when the confinement is concave toward the plasma, no matter how you twist them. Thus Stellarators, Tokamaks, etc. are (in his opinion) doomed. (And that's why his design is conVEX toward the plasma.) [google.com]

(My take on that has been that even if passive geometries are unstable, if you can get it stable enough that instability growth occurs at no more than an HF rate you might be able to use an active system to finish the job of stabilizing the confinement. But that's a separate issue.)

am i the only one see it in? (1)

holywarrior21c (933929) | about 7 years ago | (#20192449)


Proceedings of National Academy of Scientist of the united states of america
,,,PNAS
i, for one welcome our public harrasing government organizations.

This sounds familiar (1)

thatskinnyguy (1129515) | about 7 years ago | (#20192471)

It seems that what they are trying to do is create an antimatter containment field to contain the matter/antimatter reaction. Bravo! We'll be going at warp speed in no time!

Power Drain Power Gain? (1)

Ztringz (1081803) | about 7 years ago | (#20192503)

you've got a self-contained energy source that takes power to start, power to maintain, and the net energy gain is...? Make it dense enough, maybe we can produce antimatter

In Soviet Fusion lab... (1)

aqk (844307) | about 7 years ago | (#20192747)

Tokamak YOU!



Don't cross the streams! (0)

Anonymous Coward | about 7 years ago | (#20192761)

Or maybe just this one time, crossing the streams isn't such a bad idea...

Did they change the plasma flow? So instead of having to pump all the energy into magnets, the induction of the current makes magnetic fields halfway useful as its own container... That way the plasma would flow around the path that a slinky would make connected end to end instead of a simple circle like a donut. Sorta like plasma flow some folks theorize might be going on in ball lightning. And there'd be a nice "pinch point" in the middle if there weren't any physical obstructions, that might be useful.
Load More Comments
Slashdot Login

Need an Account?

Forgot your password?

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>