turn heat into electricity

[Tulse]

The foil captures x-rays, not the alpha particles, which go out in a beam. And there are plenty of other commercially-available x-ray sources around. If one uses deuterium, then the reaction produces neutrons, but there are plenty of other commercially-available neutron sources.

In other words, a FF reactor does not do anything that other, far more easily obtained devices do.

[Brian H]

Tulse wrote: The foil captures x-rays, not the alpha particles, which go out in a beam. And there are plenty of other commercially-available x-ray sources around. If one uses deuterium, then the reaction produces neutrons, but there are plenty of other commercially-available neutron sources.

In other words, a FF reactor does not do anything that other, far more easily obtained devices do.

Although it can, it seems, be modified to produce superdooper Xray beams. Go to the LLP site and check out the XScan subsections. Earlier, that product was planned as a money-maker to support the FF development.

[texaslabrat]

Axil wrote: I do not intend to offend anyone; this is only a devils advocate argument.

A sub-national group steals an unguarded FF reactor from an unattended site. They then modify it to burn deuterium instead of boron. In this conversion process they replace the multi-layer foil electric generator with a beryillium/U238 blanket. They then operate this reconfigured reactor covertly for three months. They then chemically reprocess the Be/U238 blanket to extract plutonium.

Is this not possible?

What design provisions are necessary to preclude this scenario?

They’re gonna rack up a heck of an electric bill doing it that way (effectively, due to the energy budget of the process and the fact that no electrical energy is being made here, you are basically supplying all the energy for the reactions from the wall socket in a brute-force sort of way)…and 3 months is really quite, quite generous considering the amount of plutonium needed for a crude base-line implosion fission weapon (~10kg) with this sort of transmutation technique :p Unless this group also owns their own power plant and thus has access to unlimited free electrical power (how many did they steal? These things are small but they’re not THAT small!), you are probably looking at 30 years rather than 3 months if this is supposed to be done “on the sly” in some warehouse in the industrial district. The mechanics of fusion pinch reactors has been known for a long time (assuming your goal is not to have net positive energy production but instead just want to make high-energy fusion products)…yet everybody still makes their plutonium pit material (of those who are making them..N Korea for example) from breeder reactors. There’s a reason why. Plutonium can be made in particle accelerators too…but there’s no outcry about regulating those by the IAEA for non-proliferation issues. And the efficiency rate would be about the same as the modified FF device you’ve proposed from what I can surmise.

And I’m far more concerned that the sub-national group has obtained a large amount of refined U238 with which to attempt Pu239 production without drawing attention to themselves. Perhaps they went on a scavenger hunt in Serbia digging up expended A-10 round fragments from the soil? Creating a neutron source is relatively trivial these days for a group with a decent amount of financing…you don’t need a FF device to do that. What you are effectively asking is what design provisions are necessary in the manufacture of kitchen knives that will prevent violence in a world where an AK-47 can be had for under $100. A valiant goal yes..but not likely to make a difference in the big scheme of things.

[Rematog]

I am a lay person in regard to nuclear physics. With that said, I ask the following question:

Is the 5,000 watt FF a more powerful ion and/or x-ray source then the others mentioned as ways to breed plutonium?

If so, then yes, it would be a proliferation threat. But, I don’t think it would be one that could be controlled. And stealing a distributed generation module is not the real risk.

If it works as well and cheaply as this board has been assuming, then FF modules will be copied (some licensed, some not…China has a record of not respecting intellectual property) around the world very soon. We will encourage it! The world will want cheap power to reduce poverty and reduce CO2 emissions… so FF will be everywhere.

A large sub-national group, or just a regular small nation state with an axe to grind, could buy 12 modules (installed cost, roughly $12 million, a single well heeled group could raise this much) and running 3 power modules to supply power to one “breeder” could have 3 breeders running day and night…. a year or two later, enough plutonium for a dirty bomb, at the very least… maybe a couple of years more for a small fission weapon….

In a FF future, non-proliferation would, IMHO, have to concentrate on uranium supply, FF modules will be ubiquitous.

[Rematog]

Note, by “more powerful ion and/or x-ray source” I meant quantity, not energy state of individual ions/x-ray photons.

Second…. think about trying to license and inspect, world wide, every FF module. Refer to my previous posts about number of modules needed, in the US alone, just to generate electrical power for current usage…. over 200,000 modules.

“Based on total US electrical generation capacity of 1,032,000 MW (Jan, 2009 per Energy Information Administration figures), you would need 206,400 FF power modules of 5 MW capacity to equal this. “

So world wide, what, 1 million modules…and with load growing to double the current load in US and and triple world wide in 20 years (less developed countrys will have more load growth to catch up with western standards of living), that would mean something on the order of 3 million modules in 20 years…

Sure, the world regulatory bodies won’t lose track of a dozen modules out of a world wide population of 3,000,000. That’s at least 0.0004%… and we all know international governement agencies are 99.9996% accurate, and can’t be bribed or fooled….

The world will continue to be dangerous and bad things will happen….just hope my kids and grandkids aren’t in the city that happens to be unlucky…

[Rematog]

But, before you think I’m negative about things…. I believe that a world with 3 million FF modules in 20 years is to be strongly wished for… yea, it will add some risks but…

The reduction of poverty will reduce more risks than the deployment of FF would cause.

and

It is already a riskly place.

and

Despite how terrible the detonation of a small fission device in a major city would be…. it’s a lot less terrible than the all out nuclear exchange between the USA and USSR would have been… and I grew up halfway expecting that to happen, so the world is already a lot better then it was when I was my children’s age.

[dash]

texaslabrat wrote: a world where an AK-47 can be had for under $100

Do you have a source for this? I’d like to buy 20 at that price.

[texaslabrat]

dash wrote:

a world where an AK-47 can be had for under $100

Do you have a source for this? I’d like to buy 20 at that price.

Most any gun show around here…but they are the cheap Chinese versions not the Russian ones. Not that it matters much.

[Phil’s Dad]

I’m with Rematog on this one. I wouldn’t ban water just because it can be a killer used in the wrong way.

[Axil]

Here are some of my opinions; all of which are subject to change based on your opinions and discussions thereof:

First, the FF reactor as currently envisioned is too small to effectively control and police world wide and I think such control will be required in this day and age.

To meet the world’s energy needs, a bigger reactor form factor is called for. This is not to say that a 5 Mw form factor has no place in the world power tool kit; on the contrary, it could be very useful.

Flexibility and many form factors and design approaches are optimum.

For example, the US navy needs a new high power dense reactor for their subs and aircraft carriers. About 100Mwe to 200Mwe would fit the bill nicely.

A small 5MWe reactor might be useful to supply power to a small marine base in the desert.

Second, I am not yet convinced that boron fusion is worth the pain and very low power density that goes with it. For me, deuterium fusion is the “Holy Grail”.

For another thing, neutrons are not to be feared from an engineering, operations and maintenance (O&M;), or a proliferation perspective.

Alpha particles damage fusion reactor structural material more than neutrons do because of the electric charge that they carry. On the other hand, material is available that can withstand high energy neutrons for a very long operational period without part replacement especially if these high energy neutrons are thermalized near the plasmoid. Using heavy water as the fissile material is one way to do this.

I think that the multilayer foil electric generator currently envisioned for the FF reactor won’t last very long; but time will tell on this.

Using molten salt as the “heat” exchange medium can provide power conversion efficiency greater than that of the direct conversion shell/ ion tube.

[texaslabrat]

Axil, you want FF to be a Tokamak when it really, really isn’t for a very good reason. You’ve completely missed the point and the elegance of aneutronic fusion. Deuterium may be the “holy grail” for you…but it’s not for those who want fusion without the downsides that D-D fusion brings.

Neutrons are not to be feared from an engineering et al perspective? Yeah, I guess if you don’t mind the structure turning brittle and becoming long-lived radioactive waste..I suppose that’s true. Good luck finding someone who wants to maintain your gear in that scenario though…and the long-term radioactivity will GREATLY reduce the appeal and rate of adoption of the technology into the mainstream. Nobody wants a fission reactor in their neighborhood…and a D-D FF reactor would have many of the same negative traits.

Great idea about thermalizing the neutrons with heavy water so the reactor vessel won’t be damaged. So, instead of just going with nice and clean aneutronic Boron-Hydrogen reactions and getting a direct-to-electric conversion in a setup that has such simplistic elegance that a refrigerator factory should be able to mass produce it…you want to try and put a heavy water shield around the plasmoid (which is a pumped vacuum, btw), and THEN capture the energy as heat (and requiring all structural components be designed to withstand the high temperatures that you want to transfer to the molten salt loop..and what happens to the heat captured in the heavy water shield if you want to eventually heat salt to 700C? You putting in an electric heat pump to step up the temperature too or do you plan to run it at earth-core pressure?) and THEN run everything through a Carnot-limited heat engine attached to a mechanical generator to eventually produce….wait for it….electricity? Great solution if you were the captain of your school’s “Rube Goldberg” device team. And then there’s the tremendous additional capital costs of such a setup that is orders of magnitude higher than the as-envisioned FF system. Ever priced a gas turbine engine?

Let’s just assume for a moment that a Brayton-cycle based power generation scheme WAS more efficient overall from a pure watts produced from a certain amount of fuel burned (and I’m not convinced that it is..just playing devil’s advocate as you are) perspective. Is that the metric you are using? Ok…assuming that’s the case…and let’s say it’s even 10 times more efficient. Heck, let’s say the deuterium is FREE in this scenario. What does a year’s worth of Boron fuel cost versus a year’s worth of deuterium? Congratulations..you’ve saved a couple thousand dollars a year (or in that ballpark). In the process, you’ve made the actual total device 10 times larger (at least), made it far more complicated to manufacture, and thus at *least* 10 times as expensive (or if you forgo the neutron shielding, you’ve now made the manufacture a little cheaper but now the NRC requirements will make it 100 times more expensive due to the radioactive waste you will create over time). It’s going to take a lot of years of that few thousand bucks/year to make up for the additional $3million-plus you’ve sunk into the system (compared to a $300k FF system of equal electrical generation capacity). Nevermind the huge increase in ongoing maintenance costs for all the additional mechanical components (and very tight-tolerance, expensive ones at that). Or you could have just built 10 FF systems and had 10 times the power output for a nominal increase in fuel costs (either way the fuel costs are negligible in the larger scheme of things when you are talking a few kg a year that produces millions of kilowatt-hours of sellable power).

I know if I had $3million to invest in one setup versus the other..I know which one I’d pick. I’d pick the one that put out more power and made the most profit for me for that $3 million spent…and that one sure as heck isn’t the one that requires a gas turbine engine 😉

[Brian H]

texas;
good posting; thanks for saving me the effort and time! 😉 But there is a change-of-paradigm issue (one of several, actually) Axil and others are responding to here: the sheer numbers of FF modules is overwhelming compared to existing large plant. The utilities and others are used to and comfortable with big. “Proliferation” of small units (though, as I discussed with A. and R. elsewhere, clusters and stacks are quite feasible) will present all kinds of choices and incentives to industrial, civilian, and military users that haven’t been at issue before. So there will certainly be much more distributed generation, often for projects and options that simply never existed previously.

As I said once or twice: once this genie is out of the bottle, there’s no stuffing it back in. By regulation or monopoly muscle or any other way. The dollar slope is just too steep, and expenses will aggressively seek the lower level.

[Axil]

texaslabrat, thanks for your response. Please allow me to add some detail to my position.

Axil, you want FF to be a Tokamak when it really, really isn’t for a very good reason.

A Tomamak is not what I had in mind. The LIFE inertial confinement laser reactor is closer to my concept but not very close.

You’ve completely missed the point and the elegance of aneutronic fusion.

Everything has a downside even aneutronic fusion. For a commercial fusion reactor the ‘fusion energy gain factor’ (Q) must be at minimum about 30 and ideally at about 50. That will be very hard to achieve if not impossible with aneutronic fusion. But I could be wrong in the end; I hope I am.

Even D-D fusion is hard to achieve but it is ideal for a fission/fusion hybrid.

but it’s not for those who want fusion without the downsides that D-D fusion brings.

D-D fusion does have downsides but they can be overcome. Those downsides are material erosion due to alpha particles, high energy electrons, and neutrons.

A liquid will mitigate all these problems; heavy water. Heavy water will slow the neutrons down through mediation, and turn alpha particles and X-rays, and high energy electrons into heat that can be removed from the fusion core. This heat is removed by a cooling system; after all it is at most only 5 megawatts.

The thing that is important is only thermalized neutrons; slow and gentle neutrons that are very easy on the reactor structure.

Neutrons are not to be feared from an engineering et al perspective? Yeah, I guess if you don’t mind the structure turning brittle and becoming long-lived radioactive waste

There have been thermal reactors in operation for over 50 years and will be licensed to operate to another 20. People maintain them with no ill effects as proved by the history of these reactors.

A pure thorium cycle hybrid reactor will produce wastes that are safe in 300 years. It takes a few centuries to cool the wastes down; they are mostly platinums and rare earths.

Nobody wants a fission reactor in their neighborhood…and a D-D FF reactor would have many of the same negative traits.

I can see a nuclear plant cooling tower from my house and I have a million neighbors. There are no revolts around me.

The ash effluent from grandfathered coal power plants drop radioactivity on the landscape and that must be removed.

Great idea about thermalizing…. Ever priced a gas turbine engine.

The capacity of the plant I had in mind is between 2 and 4 GWe. That can be done using a FF reactor core to drive a thorium fission blanket.

The plasmoid is produced inside the heavy water. The electrodes and first wall are composed of polycrystalline boron doped diamond. The diamond first wall that separates the heavy water from the molten fluoride thorium salt is double walled with a vacuum to thermally isolate the heavy water which operates below 100C from the molten salt that operates at 700C.

Diamond is virtually transparent to neutrons and any neutron damage is annealed at 700C.

Nuclear fission will heat the molten fluoride thorium salt to operating temperature. The thermalize neutrons from the fusion core will take a few months to get the salt up to operating temperature as U233 is gradually built up.

The neutron fluence will be about 10e20 neutrons per second. This is the same as the LIFE laser reactor.

The hybrid will use a primary heat exchanger and a secondary heat exchanger that will drive a CO2 based turboelectric generator at 50% thermal efficiency.

The heat from the fusion core is dumped to the ambient air. Its heat output is too small to economically deal with.

Let’s just assume for a moment that a Brayton-cycle based power generation…

The price of fuel is not a cost driver. What is expensive is the “Return on Investment” on the cost of construction. This is interest on capital. Labor is also expensive.

This construction cost should be about $1000/kw.

The thorium hybrid will require about 150 people to operate. It will be the size of a pebble bed modular reactor and can be built in a factory.

It will produce the power equivalent of 1000 FF reactors that need 5 to 10 men each to operate.

150 men for the hybrid vs. 5,000 to 10,000 men for the FF reactor fleet; at 100,000 per year cost each. This is called the “economy of scale”

[Brian H]

Axil wrote: texaslabrat, thanks for your response. Please allow me to add some detail to my position.

Axil, you want FF to be a Tokamak when it really, really isn’t for a very good reason.

A Tomamak is not what I had in mind. The LIFE inertial confinement laser reactor is closer to my concept but not very close.

You’ve completely missed the point and the elegance of aneutronic fusion.

Everything has a downside even aneutronic fusion. For a commercial fusion reactor the ‘fusion energy gain factor’ (Q) must be at minimum about 30 and ideally at about 50. That will be very hard to achieve if not impossible with aneutronic fusion. But I could be wrong in the end; I hope I am.

Even D-D fusion is hard to achieve but it is ideal for a fission/fusion hybrid.

but it’s not for those who want fusion without the downsides that D-D fusion brings.

D-D fusion does have downsides but they can be overcome. Those downsides are material erosion due to alpha particles, high energy electrons, and neutrons.

A liquid will mitigate all these problems; heavy water. Heavy water will slow the neutrons down through mediation, and turn alpha particles and X-rays, and high energy electrons into heat that can be removed from the fusion core. This heat is removed by a cooling system; after all it is at most only 5 megawatts.

The thing that is important is only thermalized neutrons; slow and gentle neutrons that are very easy on the reactor structure.

Neutrons are not to be feared from an engineering et al perspective? Yeah, I guess if you don’t mind the structure turning brittle and becoming long-lived radioactive waste

There have been thermal reactors in operation for over 50 years and will be licensed to operate to another 20. People maintain them with no ill effects as proved by the history of these reactors.

A pure thorium cycle hybrid reactor will produce wastes that are safe in 300 years. It takes a few centuries to cool the wastes down; they are mostly platinums and rare earths.

Nobody wants a fission reactor in their neighborhood…and a D-D FF reactor would have many of the same negative traits.

I can see a nuclear plant cooling tower from my house and I have a million neighbors. There are no revolts around me.

The ash effluent from grandfathered coal power plants drop radioactivity on the landscape and that must be removed.

Great idea about thermalizing…. Ever priced a gas turbine engine.

The capacity of the plant I had in mind is between 2 and 4 GWe. That can be done using a FF reactor core to drive a thorium fission blanket.

The plasmoid is produced inside the heavy water. The electrodes and first wall are composed of polycrystalline boron doped diamond. The diamond first wall that separates the heavy water from the molten fluoride thorium salt is double walled with a vacuum to thermally isolate the heavy water which operates below 100C from the molten salt that operates at 700C.

Diamond is virtually transparent to neutrons and any neutron damage is annealed at 700C.

Nuclear fission will heat the molten fluoride thorium salt to operating temperature. The thermalize neutrons from the fusion core will take a few months to get the salt up to operating temperature as U233 is gradually built up.

The neutron fluence will be about 10e20 neutrons per second. This is the same as the LIFE laser reactor.

The hybrid will use a primary heat exchanger and a secondary heat exchanger that will drive a CO2 based turboelectric generator at 50% thermal efficiency.

The heat from the fusion core is dumped to the ambient air. Its heat output is too small to economically deal with.

Let’s just assume for a moment that a Brayton-cycle based power generation…

The price of fuel is not a cost driver. What is expensive is the “Return on Investment” on the cost of construction. This is interest on capital. Labor is also expensive.

This construction cost should be about $1000/kw.

The thorium hybrid will require about 150 people to operate. It will be the size of a pebble bed modular reactor and can be built in a factory.

It will produce the power equivalent of 1000 FF reactors that need 5 to 10 men each to operate.

150 men for the hybrid vs. 5,000 to 10,000 men for the FF reactor fleet; at 100,000 per year cost each. This is called the “economy of scale”

Your labor costs/staffing levels for FF are off by about a factor of 30. So the labor costs are similar, while the capital costs for the hybrid are higher than FF ($50-$100/kW) by about a factor of 10-20.
So say again why the hybrid is cheaper?

[Rematog]

Diamond containment walls…..

fluoride thorium salt ….

Heavy water,

CO2 gas turbines are the closest thing you’ve mention to “off the shelf”

“This construction cost should be about $1000/kw. ” Where do you get this figure for a very high tech, cutting edge plant?

Axil, you most likely have a PhD. but…. how much time have you spent in a hard hat and steel toed boots?

You talk about doing things on an industrial scale and cost, that are hard to do and expensive in a lab….

Would this thing run 18 months between planned 4 week outages… and have a 90% capacity factor….?

Somehow, I don’t see something like this bringing cheap power to the 3rd world.

[Author]

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