Electric fusion (inertial electrostatic confinement fusion - IEC)

Dr. Robert W. Bussard predavanje

wikipedia

I first read about inertial electrostatic confinement (IEC) fusion reactors in the Dec 1998 issue of Analog and became quite enthused, but it seemed like I never heard anything further about the topic. As years went by with no news, I had to assume the idea turned out to be a technological dead end.

Little did I imagine, EMC2's contract with the US Navy prevented them from publishing anything or talking about any specifics of what they were doing. That situation continued until very recently when budget tightening (prompted by the War in Iraq) forced the Navy to shut down all their energy research -- not just IEC fusion, they cut off everything.

Now Dr. Robert Bussard has surfaced claiming that right at the end of the project they figured out how to solve the problem. Their final experimental reactor, he says, was a success. It produced 100,000 times higher rate of fusion reactions than previous IEC designs.

They've completely gotten rid of the electrode grid in the middle of the reactor. They've replaced it with a magnetic field. The reasoning being, they can use the magnetic field to trap electrons in the center of the reaction chamber, which creates a virtual electrode. Meanwhile, the positive ions are too massive to be affected much and can flow freely through the system without hindrance.

Now Bussard is pitching a proposal to build a new reactor and repeat the experiment with better instrumentation. This would cost about one or two million dollars, and would be followed by convening a panel of experts to evaluate the results. If they confirm the potential that Bussard believes it has, then the next step would be construction of a full-scale prototype for $150 million (using D+T) or $200 million (using P+B11).

The P+B11 (proton fuses with a boron-11 isotope) fuel cycle is particularly interesting since it produces no neutron emissions or radioactive by-products. The end products of the reaction are only helium atoms. It may also be possible to derive electrical power directly from this reaction with upwards of 90% efficiency, rather than having to go through the whole thermal conversion of steam-and-turbines that conventional reactors require.

The name Bussard should ring a bell, since he's known in science fiction circles for inventing the idea of the Bussard ramjet for interstellar propulsion. What I didn't know was that he also co-founded (with Robert Hirsch) the US nuclear fusion program, which is mostly based on Tokamak research. He doesn't have many kind things to say about Tokamaks (superconducting cathedrals!) these days, though.

Here's an interesting quote: "The R&D device to build is small and fixed and quick and cheap -- quick and cheap not compared to my budget, but quick and cheap compared to the eighteen billion dollars we've spent -- and it's straightforward testing of critical physics. These are all classical physics machines, and that's one of our problems in finding people to hire. Nobody's trained in gaseous electronics anymore, nobody's trained in gyrotrons and thyratrons. You can't find people who do the work of (Irving) Langmuir in the 20s and 30s and that's what we need."

I've watched the presentation a couple of times. The first time I couldn't understand most of what he was saying. The second time I learned more about fusion reactors than I ever imagined knowing. I'm convinced his experiment needs to be done (or re-done, really). It's at least as promising as ITER -- probably moreso -- and the cost would be far less.

Google recently paid $1600 million dollars for YouTube. Their annual electricity bill probably isn't much less than $200 million. Somebody, somewhere in the world, needs to step forward and fund this. If nobody does, then our civilization really deserves to lay down and die.

Mnenja?

Hja, sem gledal filmček par dni nazaj. Samo meni se pa ni zdelo STja s tem niti vznemirjat.

Prmejduš, rečem na filmček!

Ne, hočem rečt da ni nujno, da naklada. Da lahko še res pride do kakšnega zlivanja.

Ker od lokalnih fizikov ni slišat besede, kopija posta z useneta:

Can The Problems Be Overcome?

While machines based on Farnsworth's Fusor are indeed easy to build, and worked better than any thermonuclear fusion machines until quite recently, it was immediately apparent to the researchers that they could never reach breakeven. The reason, quite simply, was that either configuration required grids, and grids simply could not be built more than about 98% transparent and be expected to support their own weight, especially as they typically run red hot when fusion conditions are achieved. The machines seemed doomed to operate at no more than 0.01% of breakeven.

A few researchers struggle on, tantalized by the fact that the machines seem to have modes of operation which are better than theory predicted. Dr. George Miley of the University of Illinois has shown that a "star mode" develops in which recirculation passes primarily through the grid openings, reducing grid losses. There also appears to be considerable fusion occurring immediately outside the convergent focus region, where head-on collisions dominate, which was neglected in early analysis. Still, these improvements fall far short of what is needed for a power reactor. Basically, the grids had to disappear!

A way may be forthcoming. The actual inventor of the scheme below asked me to drop my original glowing testimonial. He is entirely too modest, if you ask me, but I understand his motives. Still, he isn't getting off without his name being mentioned here, and at least a few of his extensive accomplishments. You may have heard of him as the inventor of the interstellar ramjet concept featured in Tau Zero and many other science fiction stories: Dr. Robert W. Bussard. In the 1950's, he proposed and designed a workable nuclear fission rocket engine, which led to KIWI-A, the first predecessor of NERVA. KIWI-A was ready to test before Sputnik was launched.

Dr. Bussard also worked with Dr. Hirsch in the thermonuclear fusion pro gram at the old Atomic Energy Commission, predecessor of the DOE. Both of them recognized the finer points of the IEC machines, and wondered if a way could be found to get around the grid problem.

When life hands you a lemon, it has been said, you should make lemonade. Dr. Bussard was struggling with another of his inventions, a small tokamak called the Riggatron, which looked marginally workable, but had turned out to be far too expensive to build with the available money. The enormous energy required to bring the magnets up to a field strength that would trap the plasma would require a monster flywheel-generator that was simply way over budget. The problem with tokamaks, he realized, was that ions are so damnably hard to trap with magnetic fields, particularly under fusion conditions. Yes, using superconductors, or by putting copper coils very close to the plasma and pushing them to their limits, it was possible to trap light ions like deuterium and tritium, but as soon as they collided they would tend to jump field lines, unless the fields were especially powerful. Achieving that field strength was turning out to be a killer problem.

It was a pity, Bussard thought, that ions are not as simple to trap with magnetic fields as are electrons. Because electrons are thousands of times lighter than fusion fuel ions, they are deflected easily by much weaker magnetic fields. If the little tokamak contained only electrons, they could be held at high energy and density quite efficiently. And then an epiphany struck.

It might just be possible to build an EXL machine with magnetically insulated grids. The magnetized grids would accelerate electrons just as well as wire grids, but it would be next to impossible for the electrons to actually bit the grid. Ions formed just inside the grid would be drawn into the potential well and oscillate until they collided, totally unimpeded by grids, and trapped by the one thing that holds them vigorously-an electrostatic potential. From time to time, theory seemed to pose a fatal obstacle, but each time a closer analysis of the obstacle revealed a solution that made the theory work even better.

Funding was found to build a largescale (1-meter radius) machine, which demonstrated that the system could produce a deep potential well. Further small-scale work showed successful magnetic trapping of dense electron clouds. Theory and computer simulation seem to support the models and experiments, with no roadblock problems found, yet.

The theory and preliminary lab studies look good. A few million dollars would fund a working prototype, and if that doesn't work, indications are that scaling up a factor of ten in volume almost certainly would. While not cheap for most of us, compared to the DOE budget for the last 20 years it is practically petty cash. Will it succeed? At this point, only time will tell.

The Possibilities

If successful, the impact of this type of reactor would be enormous. I need not describe the overall economic consequences in too great a detail to this audience: science fiction is chock-full of stories in which we developed cheap, clean fusion to replace petrochemical fuels and to power our spacecraft. However, Bussard's magnetic-grid EXL version of the Fusor shows promise as a power source that sounds like science fiction. One reason is that it doesn't have to run on nasty neutron-producing fuels like deuterium and tritium.

As mentioned earlier there are many nuclei which can produce net fusion energy besides deuterium, tritium, and helium-3. Most of them are not commonly discussed, because they require far higher collision energies than DT reactions. Since DT reaction conditions themselves are a formidable challenge for thermonuclear approaches, the other fuels are simply out of the question for tokamaks or ICF systems. These limitations become almost trivial in spherical convergent focus accelerators, however. By simply jacking the voltage up to a couple of hundred kilovolts, the electrons can be made to produce a deeper potential well, and the ions race to the focus region faster. This requires scaling up the hardware, but does not appear to require any great leaps of technology.

Among the fusion fuels is a favorite of Dr. Bussard: the reaction between ordinary hydrogen nuclei (protons) and boron-11. Boron can be mined as borax or other minerals, and is readily extracted from seawater. About 80% of natural boron is the boron-11 isotope. The fuel is plentiful.

The p-B11 reaction is ideal: When the two nuclei fuse, they form excited carbon-12, which is unstable and almost immediately begins to fly apart. In two rapid stages, it casts off an energetic alpha particle (a helium nucleus), then the remaining nucleus splits into a pair of alpha particles. The first particle, carries 43% of the reaction energy, and comes off at precisely 3.76 million electron volts, which turns out to be very handy. The other two alphas come off at an average of 2.46 million electron volts each, over a spread of energies. Finally, the reaction produces no neutrons or high-energy gamma rays. There is a little bremsstrahlung ("braking radiation" basically x-rays) from collisions associated with the reaction, easily shielded. Alpha particles are dangerous if produced in your body, but can be stopped by the thinnest of shields, and are essentially harmless in a reactor vessel. Once they pick up two electrons, alpha particles become helium, a harmless
inert gas. There is no radioactive waste produced in this reaction!

Lithium can also undergo similar reactions, producing charged particles, and is an alternative fuel for such a reactor. Most nuclear power generation systems produce heat by one mechanism or another, which is in turn used to heat a "working fluid" to run turbines or otherwise do mechanical work. The process of converting heat to mechanical energy by such means is inherently inefficient. Rarely does more than about a third of the energy end up in usable electrical or mechanical form, and the theoretical limit is around 40% for most practical fluids, engine materials, and operating temperatures. This fact has depressed thermodynamics students for the last century or so, but there appears to be no getting around it using primitive "Promethean" technology.

While you could simply, allow the alpha particles from the p-B11 reaction to slam into the reactor walls producing heat, there turns out to be a much better way to extract their energy. Alpha particles, which are helium atoms stripped of their two electrons, have a charge of +2. Each of the particles produced by this reaction has a kinetic energy of around 3 million electron volts. An electron volt is the energy a particle of charge 1 will pick up when accelerated through a field of 1 volt. The reverse is true, too. To slow down a 3MeV particle with a charge of +2, simply decelerate it with a +1.5-million-volt electric field. The particle will just kiss into the charged surface, and draw two electrons from it, producing current at high voltage. This method has been used to extract small amounts of power from alpha-emitting radioactive substances, and should also work for a large reactor of the correct configuration.

The correct configuration is a spherical vacuum chamber (which this reactor just happens to be) with several charged grids to pick off the lower energy alphas, and the outer walls charged to catch the high energy alpha. It should be possible to approach 95% conversion of fusion energy to electricity with such a system (the rest being lost to bremsstrahlung and a few other minor mechanisms). This is quite remarkable-a nuclear reaction which allows almost all of the energy produced to be directly converted to high-grade electrical power!"

To paraphrase Ligon, the details of making a working EXL fusor reveal a number of possible refinements in the design that make break-even operation plausible - at least more so than years and years of trying to housebreak the H-Bomb into a viable power reactor.

We'll never need or want the storm of neutrons that a "working" thermonuclear power reactor would create. Strangely enough, we don't seem to have seriously tried (by the standards of the thermonuclear fusion research community/lobby) to develop electrostatically-confined fusion, which doesn't have a neutron flux problem worth considering.

You can just tell that fusion power has been a government-managed project from beginning to end, can't you?

Vance P. Frickey

Stvar je zelo zanimiva, samo res bom moru materiale še večkrat prebrat, pa še vmes kam drugam pokukat.

Ne štekam povsem, kako tip ve, da ioni ne bodo ujeli kak elelktron ali dva pri preletu skozi elektronski oblak in kako dejanjsko drži elektrone v tistem oblaku. Ja, z magnetnim poljem, ampak ne predstavljam si točno kako.

> Ne štekam povsem, kako tip ve, da ioni ne bodo ujeli kak elelktron ali dva pri preletu skozi elektronski oblak

To lahko storijo samo pri dovolj nizki temperaturi. Sicer jih kaj hitro spet zapusti. IMHO.

Ne vem, ne vem kako bo tole laufalo, ampak v principu ne vidim kakšne temeljne ovire.

Sem bil pa "fuzijski skeptik", vse do tega filma.

Samo eno vprašanje:
Kaj se zgodi, če se pri fuziji kaj zalomi? Recimo zmanjka štroma za vzdrževanje magnetnega polja, nekaj prebije,...

kakšen rizik "meltdowna" predstavlja takšen reaktor?

na konc pravi da so rešl fizikalne probleme, ostajajo še inženirski. začuda pa na netu ni najt kej konkretnga na to temo. še to kar je, je iz 60ih let.

noben ne upa izpadit hoaxbeliever?

to je res. da pa so bli edini ki so delal v tej smeri mi je pa mal čudno. sploh ko prav da nitii niso mel kej hudo velik dnarja.

ma pa tip baje vse ključne patente. usa dvigne nos, evropa in japonska sanjata ITER, kitajci mu dajo laboratorij in četo oldschool inženirjev pa smo lahko lepo v riti. če se stvar obnese seveda.

Samo eno vprašanje:
Kaj se zgodi, če se pri fuziji kaj zalomi? Recimo zmanjka štroma za vzdrževanje magnetnega polja, nekaj prebije,...

kakšen rizik "meltdowna" predstavlja takšen reaktor?

Zgodilo bi se ene tolk, kot če ti recimo "neonko" raznese- če jo priklopiš recimo direktno, brez dušilke.

Ajde, majčkeno več. Če bi kdo stal tam neposredno ob komori in bi pomotoma odtranil kos radiacijskega oklepa, bi ga mogoče ujelo kaj alfa žarčenja, če ga ne bi prej scvrla svetloba. Lahko bi razneslo komoro ampak to je bolj tko- v najslabšem primeru reda velikosti eksplozije plina v stanovanju ali kaj takega, verjetno še to ne.

Cela fora je v tem, da se "gorenje" lahko dogaja samo če vse dela 100.0%. Najmanjša malenkost zaduši reakcijo in ostaneš z nekaj bolj ali manj inertnega plina. Ja, vodik (devterij, tricij) gori, ampak par m3 vodika je totalen mušji prdec na tej skali stvari.

Glede varnosti ? Kot vem, še bistveno bolj. Tudi ko bo delal, bo delal komajda.

Najmanjša sprememba parametrov ga lahko samo ugasne.

O tej fusiji se govori že vrsto let, a še vedno ni nič. Ali je mogoče postaviti vsaj okvirno oceno kdaj bi ta zadeva lahko zalaufala, tako da se bomo končno rešili razne ropotije, kot so kolektorji, sončne celice, jedrske elektrarne, termoelektrarne,...

In ali je to sploh mogoče, pe ne samo zaradi problemov s tehničnimi reštvami, ampak zaradi propada energetskih lobijev??

Torej lahko rečemo, da so vsi ki še razmišljjo o drugih alternativnih virih energije 100 let za kačami in samo po nepotrebnem zapravaljajo denar za nepotrebne investicije.

Hm dons sm neki slišu po radijo o podpisu pogodbe o gradnji fuzijskega reaktorja ITER v franciji do leta 2018.
Ve kdo kaj več o tem in kolk je to glede na tele zadnje novice sploh smiselno. Ker če tole tu drži potem bodo tako rekoč gradili zastarel reaktor ?

Bussard:

The power output goes with seventh power of the radius. There is no point in making it half size. Power would be down two to the seventh. About two and a half meters for p+11B. It doesnt become aircraft carrier.

Stvar dimenzijsko praktično ni skalabilna. Pomanjšana verzija za v avto torej odpade:)

Pomanjšana verzija za v avto torej odpade:)

Odvisno s čem se voziš...

Kakšen soliden 40-tonski MAN z dirkalnimi gumami na vseh 20 kolesih, z dvema reaktorjema s turbinskim vpihavanjem Bora-11 (=twinturbo) in pospeševanjem 0.2s 0-200 bi znal presenetiti radarje na avtocestah...

Brez veze komplicirate z baterijami.

Brez veze kompliciraš z "odvzemnimi kanali".

Ja za take pospeške bi rabu takšno opremo, kot jo imajo piloti nadzvočnih letal, da ti neb kake žile razf*** , pa še vseen bi te za ene 20 cm v stol pogreznal

Dr Bussard je bil tudi gost na International Astronautical Congress. Valencia, Spain. October 2-6 2006

Od tam je tale malo podrobnejša predstavitev njegovega dela:
The advent of clean nuclear power

Če je vse to res, me prav zanima kaj bo potem ITER naredil s svojim tokamakom? Morda ga bodo cigani uzeli za staro železo?
Se mi pa zdi pametno da se probava na več področjih, samo na enega konja stavit je malce tvegano.

Iz Wikipedije :

IAS unites 1189 scientists and philosophers, politicians and public figures of the world. Among them there are 120 Nobel Prize laureates, more than 30 former and acting ministers and head of states and members of 81 national academies. Over 40 universities from different countries and many research centers are institutional members of the International Council of Scientific Development Network (ICSD)

Dokaj kredibilna organizacija. Brihten je tale Bussard! Ker je vedel, da ga nihče ne upa vzeti resno, je dal svoj izum na karseda težak test. Izgleda, da mu bo treba počasi verjeti!

Ameriška mornarica bo financirala Bussarda in njegov projekt fuzije.

Blo je na Slashdotu.

Sicer je blo potem rečeno, da je šlo za neko zaknjižbo in da ne gre za pravo nadaljevanje financiranja, le da enega dela predvidenega denarja še ni porabil ali nekaj takega in da bo imel še nek kratek čas mir. Če je verjeti Slashdotu, seveda.

Navy mu mora denar dati že ravno zato, da mu ga ne bi dal kakšen izven US.

Ni za riskirat!