[BSFusion]

NIF

[BSFusion]

A thread titled “Is lithium in FLiBe going to cause unsurmountable problems?” has been started at a LFTR site.

Please stay on topic here, and use this link to redirect there.

[BSFusion]

Joeviocoe wrote: Has any confirmed BSF experiment ever produced ANY neutrons and ANY energy level?

There has never been an experiment performed on a completed BSF device, because BSF is only an idea, having just recently been discovered; the necessary, interconnected parts, do not exist together, as a whole, in one place, but, nevertheless, each of BSF’s subsystems has been verified to work in isolation, at least conceptually, based upon examples of proven technology.

Joeviocoe wrote: Is there ANY peer-reviewed (non-discredited) research that suggests that ANY fusion (even DT) can be achieved using this approach?

BSF’s approach to ignition is similar to the concept of an “exploding pusher,” as explained in Phys. Plasmas, Vol. 2, No. 11, November 1995:

“…Higher implosion velocities are possible in certain types of high-entropy implosions, in which the high-density shell is heated rapidly to high temperature and then explodes. In a so-called “exploding pusher target,” the center of mass of the shell or “pusher” is almost stationary as it explodes. The radius of the boundary between the inner edge of the shell and the fuel typically converges only a factor of 3 or 4. Such targets are quite insensitive to asymmetry. The direct-drive, electron-conduction-driven exploding pusher target was the most common early ICF target and was the first type of target to produce thermonuclear neutrons…”

Joeviocoe wrote: …The BSF problems and limitations are not known because nobody in the scientific community has even looked at it yet. So to claim that a problem is “solved” is way too premature. A patent application cannot identify the shortcomings in the design or theory. You MUST write the paper…

I agree, patent applications are not held to the same standards as professionally written journal articles, and I pity the unfortunate patent examiner who’s job it is to process mine. I also agree with you that it would be easier for an outsider to scrutinize the key concepts of BSF if a peer reviewed paper were published. But, it would be foolish for me to start writing that paper. There are certain requirements, unknown to me, that must be adhered to if one wishes to write a such a paper. Perhaps if I had had more exposure to reading scientific articles, I might consider attempting to write my own, but my knowledge is limited to a few “Scientific American” magazine articles that I read many years ago at a local public library, before they stopped carrying that subscription. That said, I would still like to continue improving my patent application, filling in missing details and making it easier to read. You could assist with that project, by pointing out the things about BSF that you find questionable. I expect some mistakes will be found in BSF’s patent disclosure, because it is so complex. Perhaps someone with a special expertise or willingness to look at it with fresh eyes can examine it, because an opportunity for improvement may be more obvious to them. Please, let me know if any flaws or potential weaknesses are identified.

Thanks

[BSFusion]

KeithPickering wrote: Robert Hargraves is fairly down on LiF as a salt for LFTRs in his recent book Thorium: Energy cheaper than coal because the Li produces radioactive tritium inside a LFTR, in quantities higher than can be legally released into the air (in the US, anyway). That means you need a chemical process to capture and sequester the tritium, hence more expense. Instead, Hargraves suggests another fluoride salt be subsituted for LiF, such as NaF for example. Not as good a neutron moderator, but that can be finessed by putting graphite into the core.

Thanks Keith.

I do not have access to Robert’s book, but here is a discussion about lithium-7 usage in LFTRs.

AFAIK, Natural lithium is a mixture of two different isotopes, 7.5% Li-6 and 92.5% Li-7. Because it has a high thermal neutron capture cross section (see ENDF chart), Li-6 is classified as a neutron poison. If Li-6 were present in a LFTR’s LF salt, unwanted tritium would be produced via neutron capture: Li-6 + n -> T + alpha, but if the salt only contained Li-7 this would not be a problem. That is why the advocates of LFTR are suggesting such high levels of enrichment (+99.99% Li-7).

When reading the chart below, it is important to realize that the spallation events on the right side are not expected to occur inside a LFTR because the average kinetic energy coming from prompt neutrons, released by fissioning one atom of U-233 (thorium reactors produce/consume this), is only 4.9 MeV.

Attached files

[BSFusion]

zapkitty wrote: 1. Alpha particles are helium nuclei.

2. As the He nuclei are sans electrons they carry a charge.

3. An FF unit happens to eject a stream of these charged particles at high velocity along the axis of the core with each pulse.

4. If one wraps a coil around the path these particles take it is basic induction physics to charge the coil and extract work from these fast-moving particles. The slowed particles then hook up with some electrons and become the helium that is the “exhaust” of an FF unit.

As with the x-ray photovoltaics this is known physics, no speculation as to possibility required, but there’s never been any need outside of fusion physics to research the best methods of building these things… and with the tokamaks dominating fusion research funding there was almost no money to check it all out regardless.

The closest practical research along these lines was “alpha batteries” which generally rely on plutonium radiating the alphas in an omnidirectional spray. and thus are not applicable to an FF unit. However you will find that the Polywell (another aneutronic fusion contender) and its “venetian blinds” alpha collectors are closer to the alpha battery designs than anything in an FF unit.

Does this help?

I have a stupid question: After C12* fissions into three alpha particles, what happens to the electrons? Its been said that the alpha particles all fly off in the same direction, is there some reason that the electrons do not follow after them? And, if the electrons catch them, will that neutralize the charge and make the energy recovery coil ineffective?

[BSFusion]

jamesr wrote:

Do you know a book with tables about cross sections for different elements, like proton or deuterium + element? It might be that D+B10 cross section is much higher than D+D at its peak value.

This is a little 30-page chapter from a larger book that discusses a number of reactions relevant to controlled fusion and fusion in stars. (Warning: PDF.) Unfortunately, nothing about D + B 10. Interestingly, it shows p + B 11 with a huge, but very sharp resonance at 146 kEV, before its main peak over 500. Could some machine be designed to take advantage of that?

The full book is “Tokamaks” by John Wesson

Although the resonance is important, the ions will be close to thermal equilibrium as so have a Maxwellian velocity distribution. If you refer to fig 1.5 on page 18 of the pdf, rather than fig 1.3 it shows the Maxwellian averaged fusion cross section. The averaged fusion cross section is slightly higher at temperatures below 100keV than it would otherwise be if you didn’t take the resonance into account. But to get to appreciable reaction rates you still need to be over 100keV.

You could try a to create a non-Maxwellian system eg a beam of protons at exactly that energy. But the energy you need to create a beam will always be many orders of magnitude more than the benefit.

I think you have the wrong source for that pdf, it has been copied verbatim from Chapter #1 of “The Physics of Inertial Fusion” by Stepfano Atzeni and Jurgen Meyer-ter-vehn (2009).

[BSFusion]

Multiphysics

[BSFusion]

Here is what the New World Encyclopedia has to say:
—

Bremsstrahlung losses in quasineutral, isotropic plasmas
The ions undergoing fusion in many systems will essentially never occur alone but will be mixed with electrons that in aggregate neutralize the ions’ bulk electrical charge and form a plasma. The electrons will generally have a temperature comparable to or greater than that of the ions, so they will collide with the ions and emit x-ray radiation of 10–30 keV energy (Bremsstrahlung). The sun and stars are opaque to x-rays, but essentially any terrestrial fusion reactor will be optically thin for x-rays of this energy range. X-rays are difficult to reflect but they are effectively absorbed (and converted into heat) in less than mm thickness of stainless steel (which is part of reactor shield). The ratio of fusion power produced to x-ray radiation lost to walls is an important figure of merit. This ratio is generally maximized at a much higher temperature than that which maximizes the power density (see the previous subsection). The following table shows the rough optimum temperature and the power ratio at that temperature for several reactions.

fuel Ti (keV) Pfusion/PBremsstrahlung
D-T 50 140.0
D-D 500 2.9
D-3He 100 5.3
3He-3He 1000 0.72
p-6Li 800 0.21
p-11B 300 0.57

The actual ratios of fusion to Bremsstrahlung power will likely be significantly lower for several reasons. For one, the calculation assumes that the energy of the fusion products is transmitted completely to the fuel ions, which then lose energy to the electrons by collisions, which in turn lose energy by Bremsstrahlung. However because the fusion products move much faster than the fuel ions, they will give up a significant fraction of their energy directly to the electrons. Secondly, the plasma is assumed to be composed purely of fuel ions. In practice, there will be a significant proportion of impurity ions, which will lower the ratio. In particular, the fusion products themselves must remain in the plasma until they have given up their energy, and will remain some time after that in any proposed confinement scheme. Finally, all channels of energy loss other than Bremsstrahlung have been neglected. The last two factors are related. On theoretical and experimental grounds, particle and energy confinement seem to be closely related. In a confinement scheme that does a good job of retaining energy, fusion products will build up. If the fusion products are efficiently ejected, then energy confinement will be poor, too.

The temperatures maximizing the fusion power compared to the Bremsstrahlung are in every case higher than the temperature that maximizes the power density and minimizes the required value of the fusion triple product. This will not change the optimum operating point for D-T very much because the Bremsstrahlung fraction is low, but it will push the other fuels into regimes where the power density relative to D-T is even lower and the required confinement even more difficult to achieve. [em]For D-D and D-3He, Bremsstrahlung losses will be a serious, possibly prohibitive problem. For 3He-3He, p-6Li and p-11B the Bremsstrahlung losses appear to make a fusion reactor using these fuels with a quasineutral, anisotropic plasma impossible. Some ways out of this dilemma are considered—and rejected—in “Fundamental limitations on plasma fusion systems not in thermodynamic equilibrium” by Todd Rider.[/em] This limitation does not apply to non-neutral and anisotropic plasmas; however, these have their own challenges to contend with.

—
When I told Todd Rider (the expert mentioned above) that I wanted him to examine BSF, he Emailed me back that overcoming Bremsstrahlung losses might be the most difficult obsticle facing the developement of fusion power, and that my approach (BSF), which combines reflection (of transparent IR, UV, and light) with local absorption (of opaque x-rays), has the potential to succeed, but that he was too busy to update his article “Is There a Better Route to Fusion?” (FusionRoute.pdf), which is a critique of all the major approaches to fusion.

[BSFusion]

@Joeviocoe,

Laser ICF projects like NIF have at least achieved fusion on some level… although it is doubtful they will ever get a complete and symmetrical burn of the fuel pellet.

That problem has already been solved, by BSF, using matter confinement, which is an extrapolation of the “exploding pusher” concept, as explained in Phys. Plasmas, Vol. 2, No. 11, November 1995:

“Higher implosion velocities are possible in certain types of high-entropy implosions, in which the high-density shell is heated rapidly to high temperature and then explodes. In a so-called “exploding pusher target,” the center of mass of the shell or “pusher” is almost stationary as it explodes. The radius of the boundary between the inner edge of the shell and the fuel typically converges only a factor of 3 or 4. Such targets are quite insensitive to asymmetry. The direct-drive, electron-conduction-driven exploding pusher target was the most common early ICF target and was the first type of target to produce thermonuclear neutrons. However, it does not scale to high gain, because all of the mass of the target is on a high isentrope, which precludes high compression.”

Note, the scaling problem mentioned above only applies to orthodox ICF, where the highly compressed, high-pressure pellets instantly disassemble into the vacuum of the chamber. It does not apply to BSF, which is expected to scale to higher gains because of its superior confinement, which prevents dispersion and allows for extended periods of compression and self-heating.

[BSFusion]

@Joeviocoe,

Sorry, but YOUR OWN patent application does not dictate the conventions of common acronyms in science or engineering. The BSF acronym stands as a general concept to be Bubble SonoFusion.

Contrary to what you just said about common usage, the combination of letters “BSF” is not currently in wide use. In fact, if you Google “BSF” cross-referenced with “Bubble-confined Sonoluminescent-laser Fusion,” you’ll only get a few dozen hits, which is a lot more than the zero hits you get when you cross-reference it with “SonoFusion.” In this situation, the strongest logical argument is an appeal to the highest authority, ultimately: “When I use a word,” Humpty Dumpty said, in rather a scornful tone, “it means just what I choose it to mean—neither more nor less.” In summary, therefore, contrary to your *minority* opinion, the *majority* opinion of my patent application dictates, by default, how the BSF acronym gets used.

As far as I can tell right now… you have a unique “APPROACH” to an old idea. And you are the only one trying to call it something completely different.

BSF is not sonofusion, it is a hybrid of ICF that combines directed energy (laser) fusion with material confinement. It is important to realize that lasers are capable of generating much higher temperatures and pressures than chemical reactions, which, even for high-explosives, are only on the order of 0.5 eV (5500 K) and 500kBar. In comparison, the flux inside a BSF reactor, at the bubble’s surface, is expected to be at least a thousand times less intense than NIF’s laser, yet, even at this relatively low intensity, when BSF’s laser fires, the material near the bubble’s periphery is expected to obtain a temperature of around 90 eV (1,000,000 K) and a pressure of around 4 Mbar. In summary, BSF’s laser produces over 30 times the heat and pressure of TNT (~3000 C and ~50,000 atm.), way more intense than anything achievable by simple acoustical methods.

I did not imply there are “connections” between you and Taleyarkhan. I implied that the general concept of attaining fusion through Bubble Sonoluminescence has been tried before, and failed. I understand that your approach to this is very different. But you do have an uphill battle since much of the science has not been proven yet.

You seem to be WAY more worried about your patent being distinct, than the science being valid. All I am saying is that you need a lot more work and you NEED to get published. Until then, it is the same general concept that has been discredited.

I’m not worried about my patent being distinct – I know it is distinct. What troubles me is that you keep claiming (a false claim) that BSF is sonofusion. I think you might be confusing sonoluminescence with sonofusion. I mentioned several times that BSF relies on sonoluminescence, which is a valid scientific phenomena, distinct from sonofusion. In BSF, sonoluminescence (the blackbody radiation that is emitted from a hot, compressed gas) triggers an outgoing laser cascade, which, after returning with amplification, heats and compresses the fuel until, ultimately, it ignites. In summary, BSF is laser fusion, not sonofusion.

It is very likely that, although your approach is somewhat different, any device based on this would suffer the same problems as conventional bubble sonofusion that Professor Andrea Prosperetti of Johns Hopkins had encountered.

This is another red herring, since BSF is not sonofusion (SF). Some of the problems associated with SF that currently prevent ignition might be eliminated by increasing the scale, but scaling alone cannot overcome all deficiencies. SF experiments typically use bubbles that are around a million times smaller than what a fusion power plant would require. Personally, I think it is impractical to scale SF to the size necessary for successful ignition, but, to be fair, it is also reasonable to upgrade ones confidence about achieving ignition, burning and energy gain as the scale increases because the size of the hot-spark and surrounding fuel is larger (meaning slower heat loss) and the implosion would proceed with increased energy. In addition, the thickness of the mixed region and loss of the hot-spark region will become less serious, and once ignition occurs… In “crum.pdf,” Nigmatulin explained that while chemical reactions can be important limitations in SBSL experiments, they are overcome in Acoustic ICF experiments due to the significant additional energy available for compression. But why dwell on SF, which is a dubious approach, when a surefire approach, like BSF, holds so much more promise?

[BSFusion]

@Jamesr,

Just to pick 2 points from your list (13 & 14) Laser technology has moved on enormously since NIF was designed – for example, new diode pumped lasers are much more efficient, resulting in less heat needed to be dissipated between shots. They are not quite there yet, but progress is good.

Yes, diode pumped lasers are more efficient than those pumped by flashlamps, I agree. The reason for this is that diodes have a narrow optical bandwidth that allows them to pump directly to certain transitions of laser-active ions without losing power in other spectral regions. In addition, there has also been progress made toward raising the electrical-to-optical efficiency, which is now greater than 80%, and lowering the cost per Watt (see chart below). But, there is another inefficiency, unrelated to the pump frequency mismatch mentioned above, that produces a significant amount of waste heat.

The term quantum defect refers to the fact that the input energy of a pump photon is generally higher than that of the output laser photon. The energy difference goes into heating the laser medium. The quantum defect of a laser can be defined as the part of the energy of the pumping photon which is lost (not turned into photons at the lasing wavelength) in the gain medium upon lasing. At given pump frequency vpump and given lasing frequency vlaser, the quantum defect equals h*vpump – h*vlaser, where h is Planck’s constant and v stands for frequency. For example, if an 808 nm pump is used to produce 1060 nm laser output, then [1-(vlaser/vpump)] = 23.7% of the energy goes into waste heat.

Unfortunately, the quantum defect in ICF turns into low-level waste heat, which costs additional energy to remove, because it has to be actively removed in order to prevent damage to the solid-state gain medium. BSF was designed to avoid this handicap; BSF pumps directly into the hot, circulating, liquid coolant, so the quantum defect can be recovered in subsequent heat cycles. And, because BSF uses a reflective spherical mirror, instead of using transparent lens for its laser optics, there is no danger of optics damage (warping, melting, or fracturing).

I’m sure someone could come up with an equally long list of points regarding your BSF concept. Have you submitted any papers to peer reviewed journal
that cover it? I find the paper format easier to scrutinise than a patent application, since journals insist on being suitably succinct.

Perhaps a list of obstacles facing BSF could be started, but, so far, no potential objections have even been raised. 😉 A peer-reviewed paper might be a good idea too, but what journal would publish it, and who would write it? Not me, I have neither the time nor the skill to undertake a major writing project. So, unless someone wants to volunteer, that idea is DOA.

Attached files

[BSFusion]

annodomini2 wrote: @BSFusion, To me you are coming across as trolling to promote you’re own concept.

In Internet slang, a troll is someone who posts inflammatory, extraneous, or off-topic messages in an online community, such as an online discussion forum, chat room, or blog, with the primary intent of provoking readers into an emotional response or of otherwise disrupting normal on-topic discussion.

Contrary to your implications, my post titled “obstacles to ICF” was dead-on the forum topic “NIF et al.” But yes, I was hoping to get some feedback on BSF, which, you should know, is a hybrid of, and superior to, orthodox ICF … errr … in my opinion. 😉

[BSFusion]

The energy released in the pB11 process comes from fusion: the fusion of a hydrogen nucleus (a proton) with a boron-11 nucleus into a stable and quite non-radioactive carbon 12 nucleus.

Humm… it instantly decays – this stable nucleus??

OK, but isn’t it also true that energy is released according to Einstein’s E=mc2, with the final products (three alphas) containing less mass than the original reactants (p+B11), regardless of whether or not there was an intermediate C12* formed?

But the C12 nucleus can’t contain the energy that resulted from its creation and it flies apart… but the [em]cause[/em] of breakup is not an unstable heavy nucleus decaying, as happens in fission.

So, are you saying, fission can only be thought of as a process of spontaneous radioactive decay, not induced through neutron bombardment?

… the energy released in the pB11 process comes strictly from fusion.

A less strict interpretation would be that energy comes from the change in mass between product nuclii and reactant nuclii.
Maybe a third option, “aneutronic spallation,” should be added to the poll. What do you think?
Anyway, this is only an opinion poll, nothing serious, but please remember to cast a vote.

Thanks

[BSFusion]

continuing….

(12) Most mainline systems (except for liquid-metal-wall ICF reactors, such as HYLIFE) have steel first walls, which are necessary to maintain a good quality vacuum and to endure the intense x-ray and neutron radiation. The first walls of all such reactors will be highly radioactive (2 to 5 billion curies). In addition, these first walls will require replacement every few years because of neutron-induced damage, either from helium embrittlement or from atomic displacements. Because both neutron energy and neutron population are reduced in the steel first walls of these reactors, neutron multipliers (such as lead or beryllium) or isotopic enrichment of Li-6 are usually required to achieve acceptable tritium breeding ratios. The same applies to magnetic fusion reactor chamber walls. For example, the STARFIRE tokamak walls will have a radioactivity of more than 5 billion curies and must be replaced every four or five years. The significance of this should not be ignored, chamber walls exposed to damage rates of 35 dpa/yr (displacements per atom per year) will require replacement every 5-7 years. Assuming that only the inner structural walls need to be replaced at 30% of the original reactor vessel cost, then about 5% of the plants lifetime must be devoted to replacement activities.
(13) ICF laser firing times need to be increased. NIF requires a timeout for cool-down and recovery after each firing. The high precision laser optics that ICF uses must cool for several hours between firings to recover from thermal expansion.
(14) Cooling the laser medium is very inefficient. NIF uses external flash tubes that create significant amounts of non-recoverable low level waste heat which must actively be removed (requiring extra energy) from the gain medium.
(15) The Halite-Centurian tests in Nevada apparently showed the DT targets might require up to 20 MJ to ignite. Current ICF designs produce less than 3 MJ.

I should point out that, none of these 15 are obstacles to Bubble-confined Sonoluminescent-laser Fusion (BSF).

[BSFusion]

Sorry if I am still not seeing the major differences. The “SF” in BSF DOES actually stand for sonofusion. It appears to be a different approach, to the same concept.

No, the accronym BSF stands for Bubble-confined Sonoluminescent-laser Fusion, as spelled out in patent appl#: 12/803901, not Bubble SonoFusion. The concepts overlap, but there are major differences. If I changed the name to Matter-confined Laser Fusion (MLF) would that eliminate your objection?

And yes, Professor Andrea Prosperetti of Johns Hopkins HAS indeed done some work on Laser ignited Sono bubble fusion. He concluded that it would NOT work.

As I said before, those links are irrelevent. Prosperetti uses a laser to create a vapor pocket inside of a tiny liquid filled tube. The focus of the laser is located a small distance away from the end of the tube, where surface tension creates a concave gas/liquid interface. The laser heats the liquid until a small vapor pocket forms. When the vapor pocket expands, it creates pressure in the surrounding liquid, which causes the concave geometry of the liquid to accelerate inward, similar to the way a “shaped charge” produces a high-speed jet of liquid metal. In summary, the article is about ink jet technology, not fusion.

One of the major advantages that BSF has over, what you are calling Prosperetti’s sonofusion, is that BSF’s laser impinges directly on the fuel, heating it to around 90eV (1,000,000 K) prior to compressing it. Laser compression, by the method of differential ionization, begins when material that is located at the periphery of the bubble is ionized, causing it to expand into the fuel, compressing and heating the fuel, until pressure (temperature and particle density) equalize. Note – the ideal ignition temperature for BSF is only 1.6 keV, much lower than the 4.3 keV of ICF.

This was all covered, in greater detail, in the patent application:

[0319] When two adjoining regions of “condensed matter” (solid or liquid) of different electron density are suddenly heated to the same extremely high temperature (high enough to fully ionize them) what will happen?

[0320] Since the temperature is the same, the radiation pressure in both regions will be the same also. The contribution of the particle pressure to the total pressure will be proportional to the particle density however. Initially, in the un-ionized state, the particle densities were about the same. Once the atoms become ionized, the particle densities can change dramatically with far more electrons becoming available from dense high-Z materials, compared to low density, low-Z materials. Even if the system is radiation dominated, with the radiation pressure far exceeding the particle pressures, the total pressures in the regions will not balance. The pressure differential will cause the high-Z material to expand, compressing the low-Z material. This type of compression is even more pronounced when low-Z gas is surrounded by high-Z condensed matter.

[0321] The process of ionization compression can be very important in a system, like BSF, where a high-Z coolant directly contacts low-Z fuel. In fact, it is interesting and relevant to note that the main effort Soviet scientists made towards an H-bomb was the “Layer Cake” or Sloika design. It employed Vitali Ginzburn’s idea of using solid lithium-deuteride fuel and Andrei Sakharov’s notion of ionization compression of the fuel…

…
But it is still very much in it’s infancy, and with all the stigma from Taleyarkhan, the physicist that has been found guilty of misconduct… you
have to prove more than the average scientist to gain acceptance for your hypothesis.

I asked you to stop, but you continue to imply that BSF has connections with Taleyarkhan and sonofusion. Why?

[Author]

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