Dr_Barnowl
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Dr_Barnowl
ParticipantHenning wrote:
That’s the neutron shielding that requires that heavy water (1 ton per m^3), but that compensates the tons of fuel required.A lot of that weight is in the wings – but you can’t put shielding in the wings for a reactor in the body. The space consumed by the reactor and shielding would displace passengers which is a non-economic prospect.
An FF powered fuel reformer is a far more likely solution to the aviation issue.
Not only does FF have to work, but you need a better battery than current technology.
The two energy techs I have my eye on are FF and EESTOR (a high density capacitor technology company), although I find FF a lot more credible than EESTOR, I’d be fairly cheery if either of them were to come to fruition. If LPP meet their goals this year then I will throw a hell of a party. Really, FF is my source of hope for the future – my instinct tells me that there are hard times ahead without a solution to the energy crisis. EESTOR would be nice, but the existing pool of ICE powered cars are not going to vanish overnight. With the predicted break-even on a DPF reactor somewhere less than a year, you can bet that as soon as they are viable, the rush to build and install them won’t end until all the coal powered stations are offline.
ParticipantStar Trek is rife with fusion – they just consider it so commonplace it rarely takes centre stage. The reactors only get mentioned in passing, but they are present in most facilities including starships. Starships only use matter-antimatter reactors because i) it’s a useful plot device and ii) the justification is that you can’t make a compact fusion reactor that emits enough power to run a warp drive well enough for modern interstellar flight. DS9 runs on fusion (two of 6 reactors that originally powered the ore processing operations on board, if you believe the extended fiction).
The “arc reactor” in Iron Man is probably supposed to be fusion. Tony Stark uses a palladium wire when constructing his prototype in a cave, which is a nod to “cold fusion” which uses palladium electrodes. It must convert energy to electricity incredibly efficiently or it would barbecue Tony from the inside from waste heat… and if it’s running on hydrogen it must get it’s fuel from electrolysing atmospheric water. Lots of impossible engineering, but great fun.
If people are going to parody fusion in film … the archetypical use of fusion reactors in film is to provide something that goes “bang” very impressively.
e.g. – The exploding hydrogen from the sonofusion reactor in Chain Reaction, the terraforming station in Aliens which is noted to be “a big fusion reactor”, the self sustaining fusion reaction in Spiderman 2 that threatens to eat New York.
Perhaps it’s worthwhile to point out that fusion is almost certainly going to be really safe, because it’s so easy to interrupt the reaction. Maybe just have a lab-coated geek flip a switch to avert disaster… not that disaster would be imminent in real reactors. The first thing many people are going to say if you propose a fusion reactor in their neighbourhood (hopefully just before “Really? That cheap?”) is “Nukular! Eeeeek!”. Eroding the perception of danger that real-life fission accidents, fusion weapons and Hollywood have attached to fusion would be useful.
Star Trek is a positive image of fusion as a depiction of a future where it’s so commonplace and accepted that it’s rarely mentioned. So is the Mr Fusion in Back to the Future. Chain Reaction puts forward the energy message well, right at the beginning, with a great speech (albeit focussing too much on electrolysing hydrogen and not enough on the fusion) – what a shame it then spoils it by blowing up a few city blocks. Maybe we should be lobbying well-known scriptwriters to put sensible, practical, reliable, everyday fusion reactors into their scripts….
ParticipantI think the thing about LIFE is the engineering sounds pretty impossible.
They use the phrase “gatling gun” and it’s about right – in NIF at the moment you have to position absolutely pristine fuel pellets with world-class precision in terms of position AND alignment.
For LIFE you need 600 a second… you can’t afford any imperfections like magazine extractor scratches … the engineering boggles.
And then you need a factory capable of churning out 90,000 of these a day – bear in mind these are cryocooled gold-uranium alloy enclosures with a beryllium sphere containing the D-T fuel mix. So you need to make 600 of these perfect targets every second from expensive and rare materials that are also difficult to handle and toxic (the tritium being the largest fraction of the cost, but uranium and deuterium are not exactly cheap and beryllium is nasty, as we already know from assessing it’s intended use as DPF electrodes.).
Whereas the DPF essentially constructs it’s own self-compressing “fuel pellets” from nothing more than electricity and tenuous gas.
ParticipantIf the military are truly there to provide peace, they could do much worse than release the schematics of a working polywell reactor to the world. And then pull out of oil-rich eastern nations.
ParticipantYou seem to have misunderstood something. since what i am trying to describe is basically a form of afterburner for the DPF
Energy is conserved – you can’t buy additional kinetic energy by adding inert mass. Afterburners only work because the mass that’s added to the exhaust stream is more fuel, which combusts, adding energy and mass to the exhaust gases, causing greater expansion of the gases and higher exhaust velocity.
You may be able to increase momentary thrust (by releasing superheated bursts of inert propellant), but you now have a much, much, much, larger propellant tank to haul, you lost energy in the preheat chamber due to thermal leakage, and the average thrust you’ll manage will be less than just venting the ion stream out of the back.
ParticipantLook at the photo of the chamber near the bottom – all 130 metric tonnes of it. And it doesn’t even include all the ancillary equipment like the lasers.
I hadn’t realized how much the alignment of the holhraum mattered either ; I just thought they blasted the outside of it, but another picture indicates the beams have to thread through the holes in either end.
So if you want to use this for serious energy generation, not only do you have to have an ammunition factory churning out at least 10 fuel pellets a second, you have to have a gun that can shoot them 10 times a second… with extreme precision. The pellets are of course the most expensive bullets on the planet, made of a gold-uranium alloy with a beryllium core, all of which is a cheap coating for the tritium in the fuel mix.
Plus all the engineering challenges of getting a huge bank of lasers to fire 10 times a second, and extracting useful working heat from a reaction chamber the size of someones apartment – so somehow you have to get all those heat exchangers in without disrupting any laser paths.
Ok… so they’re dropping an order of magnitude more energy in their pellet (669 kJ vs 10s of kJ as per “paper 1”), after a quick search we find the holhraum is made of a gold-plated uranium-gold alloy (funny how they never mention the “uranium” part in the press releases ..), and that they are using around a milligram of fuel, which is enormous compared to a DPF plasmoid.
Do any of the people who are actual physicists here take it seriously? Does it have civilian value or is it just a testbed for nuclear weapons without the weapons?
January 13, 2010 at 1:50 pm in reply to: Focus Fusion in the New York Times? Well, not exactly, but perhaps #5716ParticipantHeh, it’s “like taking candy from a baby” ; something that’s easy (but probably not very nice). Usually attributed to stereotypical villains in comic books!
The “cub scouts” are a boys club ; leading boys to a candy store is easy because the contents are so appealing. The analogy is that FF is so appealing compared to Big Fusion, for all the reasons we’re familiar with.
Giving candy to a baby? You’d be fought off by paranoid mothers afraid that it contains LSD or warfarin…
January 13, 2010 at 11:50 am in reply to: Focus Fusion in the New York Times? Well, not exactly, but perhaps #5713Participantcub scout to a candy store
You catch more flies with honey than vinegar? 🙂
January 12, 2010 at 3:36 pm in reply to: Focus Fusion in the New York Times? Well, not exactly, but perhaps #5704ParticipantHow about an iPhone app?
If people will pay $1000 for “I Am Rich”, surely they’ll pay some small amount for some cool doodad that shows they care about energy generation?
“Want to support the next generation of energy research, so you can power cool things like cars, air-conditioners … and phones? There’s an app for that..”
ParticipantAre these spark-gap switches a scaling up of a krytron?
ParticipantWarren Buffet would seem to be the mostly likely source of funding in the top 5 ; he has a consistent habit of buying long-term prospects, and pledged $50 million to the Nuclear Threat Initiative (which exists to reduce nuclear proliferation).
Since FF will probably reduce nuclear proliferation by outmoding all those fission reactors producing plutonium it would seem to fit with his philanthropic urges.. as to whether he’d consider it a worthy investment, I don’t know. He seems to “buy large”, but the FF budget would be chump-change to him.
ParticipantStupid question :
Why won’t it work to just connect all the caps in parallel and put a big switch on that single bus?
I know it’s a stupid question because I’m not an EE.
ParticipantRezwan wrote: tips on how to convert a word doc into an html doc – without all that crazy extra formatting that word sticks in there! – please let me know.
My tips would be
* Don’t use Word to write web pages.
Sorry, that’s not very helpful, but if you’ve seen the output of Word as HTML you now know why. I tend to write documents that I know have to be HTML, using HTML and CSS, by hand, in a plain text editor.
The document is heavy on the copy, light on the formatting, so just reformatting the plain text by hand as HTML wouldn’t be too bad.
* Try OpenOffice.org
Exporting it as XHTML from OOo has lots of “Crazy formatting” too, alas, but exporting as MediaWiki format really pares it down ; the resulting format should convert back to nice clean HTML without too much effort, e.g. Mediawiki to HTML
* Maybe use TeX
Possibly using a cannon to kill a mosquito ; but very good for the inevitable publication of lots of scientific papers!
ParticipantBrian H wrote: Some people say “open the light” and “close the light”.
I think that probably stems from the lights being a shuttered lamp, so more historical precedent than electrical ignorance.
I always had trouble with open / closed for circuits when I was young. Something inside equated “open” with “open lets things through”. I thought it was intuitively backwards and I think only persistent reinforcement has instilled the opposite terminology.
You open valves, doors, shutters, windows, gates, etc. to let things through. Only in a circuit do you close something to let the electrons through. Counter-intuitive.
Back on the subject of capacitor banks, what kind of voltage / energy is required? Would 194MJ at ~ 4500V be enough, or is the high voltage more important? I’m thinking of EEStor cells ; OK, they’re currently even less tangible than a net-gain tokamak … but would they be useful if they could be bought?
ParticipantThe timeframe strikes me as both aggressive and impressive… net gain by the end of 2010, which is not much more than 13 months.
If you time it right, announce it on New Years Eve…. that will be one year I party like it’s 1999.
It’s no guarantee it works.. but at least we won’t be waiting for a recursive 30 years.
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