Thorium Reactor as a purification plant

[Blue Ghost]

So, one of the hand wave aspects of Traveller is using water for fuel, presumably the hydrogen. And yet the chemical bonding with two oxygen atoms has rendered any chemical energy in the H20 molecule null and void; i.e. "you can't get there from here" kind of thing using water as a fuel (which used to be one of the big scams in the 60s and 70s ... maybe it still is, I don't know).

So, it got me to thinking. In order to separate the hydrogen from it's two oxygen companions, you'd need some kind of energy to do that. Some other power from somewhere to crack the molecule so you could re-harness the hydrogen and get it to re-react with whatever oxidizer was being used (or however power plants work in Traveller).

Which, to me at least, means a nuclear power plant. Last I heard some researchers in Japan (back in the 90s) were trying to make portable nuclear powerplants for the home. And I think one of the designs was a thorium based reactor. I wonder if that would work for starships; a thorium reactor that acts as a water "smasher" to feed hydrogen to the ship's power plant, maneuvre drive and jump drive.

I don't know ... it's just something that came to mind.

What do you think?

 

[mike wightman]

H2O means two hydrogen atoms to every oxygen atom.

You electrolyse it to release the hydrogen, which you then use for a fusion reaction.

The fusion reaction produces vastly more energy than the electrical energy needed to electrolyse the water in the first place.

Another thing you can do once you have a source of hydrogen is to recombine the hydrogen and oxygen in a fuel cell - this generates electricity, but nowhere nearly as much energy as you get from the fusion of hydrogen.

Summary - fusion reactors use nuclear reactions, not chemical reactions.

That said, using a small thorium based reactor to electrolyse the water to make the hydrogen in the event of a main reactor failure is an interesting idea - there has to be a reason radioactives are still so valuable as a trade commodity in the fusion powered Traveller universe.

 

[Condottiere]

Multiple fusion reactors and/or batteries.

 

[kilemall]

I could see a Thorium plant being the main hydrogen cracker for TL6-7 A/B starport fuel supplies.

I allow for fission plants IMTU way past TL7, as refueling only has to occur once every few years, saves on fuel space, but power plant damage in battle is..... dangerous....

And, the fuel/refuel cycle is expensive. If the power plant is destroyed, a replacement will cost just that much more for initial fueling.

Thorium would probably be a preferred choice for OTU or other universes concerned about nuclear proliferation- it makes for a lousy fission bomb source.

Also, Thorium plants have been touted as potentially burning nuclear waste, getting cheap fuel and solving that particular issue.

https://www.extremetech.com/extreme...t-nuclear-reactor-that-eats-radioactive-waste

 

[Blue Ghost]

H2O means two hydrogen atoms to every oxygen atom.

You electrolyse it to release the hydrogen, which you then use for a fusion reaction.

The fusion reaction produces vastly more energy than the electrical energy needed to electrolyse the water in the first place.

Another thing you can do once you have a source of hydrogen is to recombine the hydrogen and oxygen in a fuel cell - this generates electricity, but nowhere nearly as much energy as you get from the fusion of hydrogen.

Summary - fusion reactors use nuclear reactions, not chemical reactions.

That said, using a small thorium based reactor to electrolise the water to make the hydrogen in the event of a main reactor failure is an interesting idea - there has to be a reason radioactives are still so valuable as a trade commodity in the fusion powered Traveller universe.

Right, but how do you electrolyte it in the first place when you need the stuff to feed your power plant? It's been 20 years since I took university physics, so someone refresh my memory.

 

[whartung]

H2O means two hydrogen atoms to every oxygen atom.

You electrolyse it to release the hydrogen, which you then use for a fusion reaction.

The fusion reaction produces vastly more energy than the electrical energy needed to electrolyse the water in the first place.

This is the key point right here. The cost to create the fuel in terms of energy is less that the energy created by burning the fuel.

For example, the amount of energy necessary to chop up a tree for a fire is much less than how much burning that wood creates. But, obviously, that's not a closed loop equation. Since the wood is essentially a solar battery, storing solar radiation and other effects over time. The addition of a little more energy in to the equation by turning the tree in to fire size pieces empowers the extraction of the energy.

The issue with a starship is the "dark start" problem.

One of the concerns during Y2K was that you needed a power plant to supply power to a power plant in order to start the power plant from a cold start, but if all of the power plants were zapped out by the glitch, where do you get that kind of power? So, how do you start a starship cold?

Much like a car, you would have to have some kind of battery, or another external power source to bootstrap the ship. Something to turn the pumps to bring fuel and spark the fusion reaction.

(There's a movie with Jimmy Stewart movie, "Flight of the Phoenix", where the motor has to be started using some kind of charge similar to a shotgun shell. I don't know if that's used to kick over a magneto, or pressurize some system, or what.)

So, its clear that a starship can not be fueled by water. Rather, it needs LHyd and electricity. However, starships are large enough that they can carry the machinery to create H2 out of water.

But I've never seen a good analysis of refined vs unrefined fuel.

 

[Condottiere]

It gunks up the plumbing.

Though the better game device would have been inefficiency and/or misjump.

 

[mike wightman]

Right, but how do you electrolyte it in the first place when you need the stuff to feed your power plant? It's been 20 years since I took university physics, so someone refresh my memory.

Any source of electricity can be used to electrolyse the water:
solar panels
a wood/hydrocarbon burning engine linked to a generator
a muscle powered dynamo
hydroelectric power station
wind turbine
fission power station
a chemical battery
etc.

 

[McPerth]

So, its clear that a starship can not be fueled by water. Rather, it needs LHyd and electricity. However, starships are large enough that they can carry the machinery to create H2 out of water.

But I've never seen a good analysis of refined vs unrefined fuel.

While the H₂ cold be carried in form of wáter (and it will take less space to do so) and electrolyzed for use, I guess this will only work for the Power Plant, as the JD burns the H₂ too fast, and you ned it ready when you start it.

If HG breaking by jump rules serve, the full fuel for a jump is burned in 2 turns (40 min). How much water can you electorlyze in this time?

 

[mike wightman]

Feed water, methane or ammonia into a fusion reactor chamber that is running - that is it has a plasma in excess of a million degrees at least - and your water/methane/ammonia molecule falls apart anyway.
The hydrogen can then fuse, the oxygen/carbon/nitrogen is just 'dirt' - highly corrosive dirt which explains why CT military drives had to be 'ruggedised' to cope with the contaminants.

Traveller fusion reactors may well use grav tech to hold and compress the plasma, and at higher TL a damper technology based 'catalyser' could make the process even more efficient.

 

[AnotherDilbert]

You can collect unrefined fuel (water) from oceans and feed it directly to the drives.

Water is dipped from oceans by ships landing in the body of water and opening fuel cocks, or through the use of fuel shuttles. Fuel which is skimmed or dipped is unrefined, and may result in misjumps; fuel purification plants can convert such unrefined fuel to refined fuel for safe use.

Apparently Traveller drives are not especially picky about what chemical form the hydrogen is in.

 

[Blue Ghost]

Any source of electricity can be used to electrolyse the water:
solar panels
a wood/hydrocarbon burning engine linked to a generator
a muscle powered dynamo
hydroelectric power station
wind turbine
fission power station
a chemical battery
etc.

... start a starship like a model T? Some guy (or your wife) stands out in front of the ship with a hand crank? o:

 

[Blue Ghost]

Traveller fusion reactors may well use grav tech to hold and compress the plasma, and at higher TL a damper technology based 'catalyser' could make the process even more efficient.

This was a notion I had a few years back when I was thinking about the game. HE3 rockets use a magnetic field to suspend the plasma reaction and kick it aft. An "ultra tech" version, as per Traveller, would probably use a form of grav tech as a compressor to achieve the appropriate temperatures.

Wow. Interesting.

 

[McPerth]

Feed water, methane or ammonia into a fusion reactor chamber that is running - that is it has a plasma in excess of a million degrees at least - and your water/methane/ammonia molecule falls apart anyway.
The hydrogen can then fuse, the oxygen/carbon/nitrogen is just 'dirt' - highly corrosive dirt which explains why CT military drives had to be 'ruggedised' to cope with the contaminants.

Traveller fusion reactors may well use grav tech to hold and compress the plasma, and at higher TL a damper technology based 'catalyser' could make the process even more efficient.

See that by using water, you can store 1 ton of hydrogen in 9 kl (instead of 14), so saving 40% volumen in exchange to use unrefined fuel...

 

[kilemall]

See that by using water, you can store 1 ton of hydrogen in 9 kl (instead of 14), so saving 40% volumen in exchange to use unrefined fuel...

You could pressurize hydrogen too....

https://en.wikipedia.org/wiki/Slush_hydrogen

The metallic stuff is what I think capacitors are made of, another gravitic tech side benefit.

https://en.wikipedia.org/wiki/Metallic_hydrogen

 

[Blue Ghost]

Bootstrapping was how I saw it. You'd need some kind of basic electric "starter" to get some kind of fire or reaction going, and then the powerplant takes over the rest until you reach your next destination. At which point you land, or dock, and probably hook into the starport feed or something.

Not that the game needs to get that detailed, but it was a curiosity of mine. You obviously (at room temperature or STP at lest) cannot light water with a match, so it was a curiosity of mine.

 

[mike wightman]

You do not allow your fusion reactor to go out.

It may be stopped, refurbished and maintained and then re-started at the ship annual maintenance but for the rest of the time the fusion plasma will remain ready to go.

You could make quite an adventure out of trying to generate the electricity needed to start up a 'cold' fusion reactor (as in the reactor is out and needs 're-lighting')...

you could possibly store the energy in the jump drive capacitors to kick start the fusion power plant - all you need to do is find the minimum 1.21 gigawatts

 

[McPerth]

You could pressurize hydrogen too....

https://en.wikipedia.org/wiki/Slush_hydrogen

The metallic stuff is what I think capacitors are made of, another gravitic tech side benefit.

https://en.wikipedia.org/wiki/Metallic_hydrogen

Well, you could, but in the articles you linked I don't see what volume wil lbe needed for a ton of such hydrogen...

Aldo, having metalic hydtogen, wiht conduvtive properties, might have some drawbacks, mostly if the fuel tanks are hit and there's a short (remember fuel tanks use to be arround the hull as a layer of protection...).

 

[kilemall]

Bootstrapping was how I saw it. You'd need some kind of basic electric "starter" to get some kind of fire or reaction going, and then the powerplant takes over the rest until you reach your next destination. At which point you land, or dock, and probably hook into the starport feed or something.

Not that the game needs to get that detailed, but it was a curiosity of mine. You obviously (at room temperature or STP at lest) cannot light water with a match, so it was a curiosity of mine.

T4 got into that detail, you apparently have to have something like 10%-20% of the power output on tap to start up hot fusion. Fusion+ does not require that.

There are multiple fusion options that could be in use.

The following is very IMTU.

From various descriptions, I would define regular fusion as one of the classic hot fusions detailed here, likely with gravitic containment/compression.

http://www.projectrho.com/public_html/rocket/fusionfuel.php

Note that Lawson Criteria, that's your startup difficulty.

Fusion+ and the jump drive power surge are both likely muon-catalyzed fusion.

The former because of the cold fusion/deuterium aspect.

The latter because the muons cause fusion because they are so darn heavy and effectively compress the hydrogen nuclei 196 times- perfect for the jump drive situation where we need to feed huge amounts of fuel into a relatively small volume quickly and get a lot of juice to initiate jump.

https://en.wikipedia.org/wiki/Muon-catalyzed_fusion

I'm using CT/HG2, I figure the 4/3/2/1 breakdown of power plant TL improvements are respectively fission/D + D/D + T/p+p+p+p.

In addition, I have the He3 fusion come in as the TL8 breakthrough, with less shielding and so more output per ton, but fantastically expensive to fuel (and literally millions of tons of regolith that ends up in L-colonies).

The other drawback to He3 power plants are that they take a LOT of external power to start up, so they can never be shut down effectively. Bit of a risk when outside civilized space, but militarily this means there is no option for this sort of ship to shut down power and lie doggo.

Fission gets improved along with everything else and never goes away entirely, precisely because of that militarily useful shutdown/no startup power cost.

But it costs expensive radioactives to fuel, neutron embrittlement so definitely a lifespan, and unlike fusion the radioactivity just doesn't 'go away' upon SCRAM, it's always there to irradiate the ship and crew if things go wrong.

 

[kilemall]

Well, you could, but in the articles you linked I don't see what volume wil lbe needed for a ton of such hydrogen...

Aldo, having metalic hydtogen, wiht conduvtive properties, might have some drawbacks, mostly if the fuel tanks are hit and there's a short (remember fuel tanks use to be arround the hull as a layer of protection...).

Er, I rather thought the quoted 16-20% figure as the usable part.

I'm proposing metallic hydrogen as the core part of the capacitor, which is not about fuel and is already described as explosive when excessively charged.

Metallic hydrogen being the best superconductor, then exceeds capacity and heats up, unpacks all that electrical power AND explosive potential catastrophically, fits the capacitor criteria to me.