Nuclear synthi-jetfuel plants wanted for US Afghan bases In a potentially controversial move, US military tech chiefs have decided to investigate the idea of using mobile nuclear reactors to provide power and synthetic jet fuel at forward bases overseas. In a request for information issued yesterday, Pentagon scientists say they would like to hear proposals for "deployable nuclear …
Worked on during the early 1960s some were deployed to heat US bases in Greenland. Deployment could be managed by about 3 20 foot containers, with a *large* (800 ft IIRC) exclusion zone around 1 design to reduce (virtually eliminate) shielding. Generating hydrogen from high temperature reactors has been on the European agenda since at least the mid 1970s.
In principle HC synthesis is a step up the chain. Doable with the right catalysts and a fairly large supply of heat.
Proliferation resistance (running it on U238) is quite a feature of the breed/burn design from the Microsoft spinoff Intellectual Ventures. Most modern designs make some efforts to limit (or exclude) the enriched or highly enriched Uranium
However IIRC the reason why US submarine reactors are *so* compact is *not* the density of Uranium (19x that of water) but its *enrichment* which is high relative to the stuff in civilian plants. Excellent should you find yourself inside such a base near its reactor with a substantial supply of explosive and a sudden urge to martyr yourself.
Mine's the one with "nucle Engineering for Dummies" in it.
Changing World Technologies has been creating fuel from waste for years using TDP. Why would the US government need to come up with a new process? CWT's process is scalable from huge recycling complex to back of truck sizes. All they should need to add would be the portable reactor.
http://www.changingworldtech.com/
The obvious universal CO2 source is the atmosphere.
Extracting it from the atmosphere or, in a more concentrated form, from exhaust gasses is the standard way of making dry ice (solid CO2). This is a known, commonly used process and is obviously fairly cheap to operate. The current price for dry ice is around $US 1.00 / kilogram.
In addition to processing the sewage, it seems they could design the methane burnoff, and possibly even the engines that run on the resulting fuel, to capture the CO2 as it is being produced, to bring back into the processing. Redesigning the engines is probably pretty technically challenging, but capturing the CO2 from burning off the methane seems like a no-brainer.
I think with all these sources combined it should be trivial to get enough CO2 to maintain operations, given sufficient hydrogen.
<em>This is why anyone who is truly concerned about the environment should always, without exception, light their farts. Failure to do so is colossally irresponsible in a global warming context.</em>
According to Dr. James L. A. Roth, the author of Gastrointestinal Gas (Ch. 17 in Gastroenterology, v. 4, 1976) most people (2/3 of adults) pass farts that contain no methane. Exceptions must be allowed, else the unnecessary combustion of of matches or lighter fluid creates a greater problem than it potentially solves.
Those are the ones I had in mind. Not SL-1 had a spectacular ending when it's 300Kw output went up to about 3GW (not a typo) for less than a second, with the loss of 4 lives.
Most of the rest IIRC actually had fairly uneventful lives. The *main* reason for ending it AFAIK was the rising costs of the Vietnam war and the view that other options were nearer term and (more or less) as effective, but that was when oil was 2$/barrel.
The big problem with any of these plans is cooling the process. Oil-refineries, petrochemical plants, power-stations are sited on coasts/rivers for a reason - they all need a reliable supply of vast quantities of cooling-water.
OK, a shipborne process has the entire sea as a potential heatsink - but cooling-water by the millions-of-litres-per-day isn't exactly easy to source in Afghanistan.
Just add a huge fancoil to the reactor, and you can start cooling it immediatly.
Use the main turbine's shaft to drive the fan and you will have an inherent negative coeficient system, because the hotter the reactor will get, the quicker the fancoil will remove the heat.
Just assure yourself thar the heat is sent upwards directly, to avoid recirculation problems.
Figure that you need 40 MW of power to meet the requirements. That means that you need to dissapate about 35 MW of heat, given a VERY efficient chemical process.
How big a heatsink do you need to dissapate 35 MW, using 330-340 K outside air? (Or do you want to shutdown during a hot day?)
Also, the negative temperature coefficient of reactivity does not mean that a higher temperature results in more cooling- it means that raising the core temperature of the reactor will result in shutting down the reactor.
http://en.wikipedia.org/wiki/Temperature_coefficient#Temperature_coefficient_of_reactivity
Submarine reactor cores are relatively small, but have very highly enriched fuel. Also, the shielding is an important concern, as is protecting the reactor vs. enemy action. One airstrike could well turn a reactor into a dirty bomb. Carried bombs would be harder, as there is no need to allow physical access to the reactor to anyone in normal conditions, even the operators.
Call me stupid (and people often do) but could someone please explain how and why methane should be produced as a by product?
Bearing in mind that JP-8 is essentially kerosene with various additives and kerosene consists of molecules that are basically 6->16 (average 12) methane groups chained together, how come methane is willingly given off as a by product? Surely it would, at the very least, be recycled back into the synthesis process?
In the unlikely event that methane really is given off as waste, one could either burn it to get back some CO2 for input or more usefully, pump it into the gas grid and let someone else (with more clue) get some use out of it. After all methane is the principle component of "natural" gas.
...small reactors have almost always used highly enriched uranium as their fuel. Some even use bomb grade uranium. Even the more modern designs which use c. 20% enrichment are a serious proliferation risk as it is much easier to go from 20 -> 90% U235 than from natural uranium to 20% enrichment.
I'd like to know DARPA's plan of safeguarding nuclear materials if an American base equipped with a nuclear thunderbox came under sustained attack and was likely to fall to the enemy. It's not like you can haul a hot reactor out of harm's way.
So the whole process creates a methane by product, and methane is a viable alternative to fuel cars (will fuel LPG conversions for example).. ok so you won't get great MPG's using it, less so than LPG at present (although tweaks to systems could probably improve it). But it creates a potential new fuel source that the military can sell to help pay for it's own upkeep... Want new planes, sell the fuel so the taxpayer doesn't have to foot the bill.
Imagine how worried the oil industry would become if the military suddenly started making fuel for 'General' consumption (no need to salute, it's just a Major pun)... No chance of a price war with the US military because those guys actually have guns. :)
I'd gladly buy my fuel from them if it helped fund proper equipment for the troops being put in harms way by govts scrambling to secure (irony alert) oil supplies.
It seems to me that an army base, especially one of those remote "inflate-a-camps" can find many uses for methane.
1) Heating Hot Water
2) Cooking
3) Convert small portable, field generators to burn methane, instead of diesel
4) Convert some vehicles to use methane
5) Heating the camps
6) Go look up Thermophotovoltaic systems. Use methane as the starter fuel
7) ??
But not thinking clearly agency.
Option 1:
Small scale power plant to charge batteries, to run slow electric propeller driven drones, to spy on and drop bombs on guys on donkeys.
Option 2:
Huge nuclear plant to produce synthetic Jet fuel at 0.001% efficency to power mach2 fighter jets, to spy on and drop bombs on guys on donkeys.
Fission-based portable reactors are a nice, attractive, KNOWN technology. Very accessible.
Unfortunately, as has been pointed out both in the article and in the various comments, the risks associated with the idea outweigh the benefits.
This is one time when we MUST PUSH for stable FUSION reactor technology; it's time for Mr. Fusion to come off the back deck of Dr. Brown's DeLorean, out of the Movie, and onto the deployed forces' bases. Between the U.S. and Russia, we've been working on stable fusion power technology for over 50 years now, and they KNOW it's possible, they KNOW it can be done economically.
Tell ExxonMobil, Texaco, BP, and AtlanticRichfield that they can't keep the patents any longer. Get them out to market or get up OFF them; it's now a National Security Issue.
Yeah, I know; I sound like one of those Conspiracy Theory Idiots.
So?
Google "ITER fusion".
ITER is the 500 MW fusion reactor pilot plant currently under construction in the south of France. The fundamental physics is solved, solved, solved. However there is still some pretty hairy engineering problems involved and they don't expect to progress to commercial plants before 2020 at the earliest.
Another issue is that tokamaks can't be made small. The Q-factor depends on the scale of the device; below a certain size, it cannot be be made to be an overall generator of power. And that minimum size is too big for portability, even in a ship.
The Taliban would make it job one to fire RPGs into the American nuclear reactor. Seriously, why has anyone given thought to the contamination issues after the enemy cracks the reactor open?
If a forward operating base is overrun, well, hey, you've just given the Taliban a nice chunk of uranium with which to build a dirty bomb!
I think this idea needs more analysis, people!
Most diesel powered military equipment will run just fine on JP-8. I know that we fueled the trucks and generators with it. It's pretty common practice in Aviation Battalions. They already require enormous amounts of fuel for the helicopters, why make things more difficult by carrying two different types?
The whole "dirty bomb" thing is a tad overplayed. We hear about it plenty, but how often is it used to any real effect? Besides actually blowing up (which is probably the most effective part of a dirty bomb), the worst it'd do would be to convince a bunch of guys in hazmat suits to pay the place a janitorial visit. It is unlikely, besides the explosion itself, to seriously harm more than somebody's nerves. It takes a lot of radioactive material to expose a usefully large area to enough of the stuff to do serious harm--especially if everybody is leaving because a bomb went off. Well, I guess it has one area of efficacy: Scaring people when real threats are in short supply.
I suppose a captured reactor might have enough of the stuff to be dangerous. Then again, the *real* weapons stored at the hypothetical overrun outpost are probably a lot more dangerous in the hands of Taliban soldiers than the contents of a portable nuclear reactor, but I don't see anybody flipping out over that. Granted, those aren't radioactive, so they're totally not scary. What're a few hundred thousand bullets, a few crates piled high with machine guns, and several boxes of military high explosives next to something radioactive? Zilch as far as public opinion is concerned.
Some previous posters mentioned that this stuff would probably have to be enriched a lot to be used in small reactors, and they'e probably right. In that case, it might make more sense to try to find something more useful to do with enriched uranium than to strap it to a pipe bomb. Or maybe not--because, to build an actual atomic weapon, the Taliban guys would need not only a source of enriched uranium but all the *other* parts of the bomb. They could probably find former Soviet nuclear physicists if they looked hard enough, but what about all the explosives and the circuitry, and the manufacturing capabilities to make the parts they'd need? If they've got that, do they need to steal a tiny fuel-producing reactor?
If small reactors are so much known tech, why aren't they used to power space craft? Like harnessing a reactor to run an ion drive and flying to Mars for the weekend?
Expecting prompt answers from the nuclear boffins so clearly swarming in this forum :-)
(IT? Well that was the only icon with a question mark on it)
...but do then radioisotope thermoelectric generators onboard such probes as the Voyagers, Cassini, New Horizons et al count? I know they're technically generaing electricity from radioactive decay and not fission reactors per se. But we do have nuclear power tech flying already.
And by 'we', I obviously mean 'Not the UK'.
"..but do then radioisotope thermoelectric generators onboard such probes as the Voyagers, Cassini, New Horizons et al count?"
No. They are more like a 1 shot battery pack. They have a known beginning-of-life output and a more or less known end-of-life output. They cannot be throttled and do not have active cooling loops. OTOH they have *no* critical mass size limit as they do not go critical. RTG's are to space nuclear reactors what LED's are to semiconductor lasers. Simpler to construct (relatively) but with lower useful performance.
You *may* have heard that the general public has developed a certain reluctance regarding the use of nuclear power in *any* area which could lead to a substantial increase in the number of reactors or exposure to risky environments. If not I suggest you Google "three mile island" and "Chernobyl."
The term "Small" is *relative*.
"If small reactors are so much known tech, why aren't they used to power space craft? "
They have. Mostly by the Russians. They were also used to power ocean surveillance radar on intelligence satellites by Russian and possibly the US.
However the *massive* protests on the use of RTG for NASA and ESA missions to the outer planets make it *very* unlikely they will be used outside of the military. Multiple proposals have been made for reactor powered missions both for electric power (reactors can be throttled up and down, RTG's cannot) and for drive, both various electric thrusters and direct fuel heating.
BTW reactors have *very* poor thrust to weight ratios. Only the molten salt design *may* be compact enough and pack the energy density needed to build a vehicle which *could* take off from sea level.
It strikes me that the US could solve the narcotics problem AND the fuel problem in Afghanistan, as well as boosting the Afghan economy, by guaranteeing farmers an good price for poppies, and then converting it into biofuel. The farmers could bring it to collection points manned by the Americans (so no troops are at risk as it is transported over dangerous roads) where it is turned into biodiesel and biokerosene for use by US planes and vehicles.
Pas air through potassium hydroxide and the CO2 reacts to form something whose name escapes me but turned the flask milky white in the school chemistry experiment. Add hydrogen (produced by cracking water with lekky from the reactor) and you reform the potassium hydroxide and produce methanol.
Distill out the methanol and you have a liquid that can be used in spark ignition engines with almost no modifications - make sure the seals are suitable, and ECU software is flex fuel so it can handle any mix of petrol, ethanol, and methanol.
Methanol can be used as a feedstock to produce heavier things - like petrol, diesel, and plastics.
Bury plastics when whatever you make with it is end of life, and you have a carbon negative cycle !
it seems to me
1 the methane rather than simply being burnt could drive a turbine to produce more electricity to power the conversion - thus lessening the load generally
2 as an alternative, I've seen propane fridges, I dare say a methane 'fridge' would be simple to build, thus could assist in the cooling
3 it looks as though darpa's brief was specifically to improve generation of J-8 jetfuel - possibly mainly algal generation see for instance http://www.greenaironline.com/news.php?viewStory=346 , http://www.darpa.mil/sto/solicitations/BioFuels/ hence the focus that apparently overlooks some parallel technologies - that may be less cost-effective in fact;
so, in summary, let's look forward to less global warming hype, less pointless conflicts in ungrateful regions, relatively lower fuel prices :-)
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