Fusion reactors and high explosives

[IanBruntlett]

In last night's Traveller game, "Mission to Mithril", the Travellers decided to coerce some NPCs by installing high explosives in the starport's reactor shed.

I'm wondering - what would have happened if they detonated the explosives?

 

[CordwainerFish]

Depends on what magic the fusion reactor uses to coerce protons to fuse in a laboratory environment. For a tokamak, the answer would be "nothing, really", but Trav fusion plants almost certainly aren't tokamaks.

 

[WHULorigan]

The issue in Fusion is maintaining temperature and pressure sufficient to overcome the Coulomb (Electromagnetic) Force repulsion at subatomic scales to the range at which the residual strong nuclear force kicks in. That requires immense power and effort. Destroying that system causes it to shut down. You may still have a conventional thermal/pressure explosion depending upon the exact mechanism that is being used to achieve compression (and whatever magic nuclear damper technology employs) but you won't have a nuclear event.

 

[Condottiere]

I suspect rather more forceful within the confines of a spacecraft, especially an armoured one.

Depends on the amount of velocity and volume of the contents exiting the confines of the magnetic bottle.

If fusion is the compression of hydrogen molecules, and energy goes from a controlled release, to an uncontrolled one, things should start to heat up.

 

[Sigtrygg]

No.
As soon as the reaction vessel stops functioning the plasma can no longer be squeezed to produce fusion, the fusion process stops. So all you have to deal with is a few grams of very hot plasma.

 

[Condottiere]

I kinda suspect it would depend on how fast the magnetic bottle collapses, and internal pressure.

If it's a slow release like a balloon with a hole, it will probably droop limply.

Though, I would think, you'll get more than a sunburn.

 

[MonsterX]

According to a Mongoose published adventure which I won't name because of spoilers, nothing happens due to the reactor.

There is a lot more potential for interesting reactions if you go after the hydrogen fuel with incendiaries. The reactor doesn't NEED that much fuel to provide a lot of energy for a long time because fusion is like that, which reduces the potential for drama, but it doesn't mean they don't have big tanks of fuel. Just in case.

 

[Condottiere]

Let's see.

One tonne standard fusion reactor, technological level twelve, fifteen power points.

One tenth of a tonne hydrogen over twenty eight days, or fifty litres per day.

Fifty litres divided by two hundred forty, is 0.2083333333333333 litres per six minutes.

0.2083333333333333 litres in six minutes creates fifteen power points.

And fifteen power points is what, three hundred seventy five megawatts, or three and three quarters of a gigawatt?

Do we further divide that by a hundred to get six second combat rounds?

And finally, how of much that would be expressed in explosive force, if the magnetic bottle collapsed?

Assuming, that the reactor in the shed is fourteen cubic metres.

 

[Sigtrygg]

Regardless of the purely fictitious numbers...
There is no explosive force, as soon as the reactor is damaged the fusion reaction stops and all you have are a few grams of hot plasma, by the made up numbers it is less than that by several orders of magnitude.

0.0006 litres per second... 60 micrograms there or there about.

 

[Arkathan]

The description of leaking plasma in Flatlined for the small base reactor is exaggerated from reality, but the threat of electrocution is real. If someone is close to the breach, and in a direct line of escaping plasma, they may experience varying degrees of burns based on both the size/design of the plant, and referee fiat. The latter being the more dangerous of the two. The electronics controlling the magnets as they randomly deconstruct themselves, on the other hand, would be detrimental to anyone in the reactor compartment.
Whatever caused the breach is going to be more hazardous to people or equipment, providing the breakers prevent arcing.

 

[WHULorigan]

Hot hydrogen plasma would of course rapidly recombine to form hot H ₂ , which if leaked into a compartment with significant O ₂ could create issues in sufficient quantity.

 

[Arkathan]

Hot hydrogen plasma would of course rapidly recombine to form hot H ₂ , which if leaked into a compartment with significant O ₂ could create issues in sufficient quantity.

The reactor on Mithril is a close to a mobile advanced base sized reactor. The amount of hydrogen is very small and contents under pressure cool rapidly under depressurization. The hydrogen plasma would be hard pressed to fill a small balloon using today's standards, and would hardly provide a flash in a test tube using Sigtrygg's calculation. Then without a spark, and you are going to have a spark or several, the hydrogen/oxygen mixture needs to be at just under 1000F, so residual heat and electromagnetically deconstructing parts' shrapnel and electrical arcing are your biggest concerns, after discounting, surviving or avoiding the effects of the breaching device.

 

[Condottiere]

Spacecraft power plants tend to be rather large.

There has to be a reason for magnetic bottles, and then you have to transform that hydrogen fusion into electrical energy.

A sudden release of either, could be a rather severe case of sunburn, and whatever happens when you release large amounts electrical energy out of containment, or a capacitor.

 

[Sigtrygg]

There is no large amount of energy.
The large amount of energy is generated by the mass deficit of the fusion reaction.

The reason for the magnetic/gravitic bottle is to hold the plasma away from the walls of the reaction vessel, as constant exposure to hot pressurised plasma will severely damage the reactor over time. Where the plasma is fused (laser ignition --- magnetic/gravitic field pinching or inertial --- a combination of both) is where the nuclear energy is released.

The instant the fusion reaction stops the plasma stops fusing and all you have is a few micrograms of rapidly cooling plasma.

 

[Condottiere]

Doesn't seem quite right, considering the amount of energy involved.

To create a fusion reaction, you have to compress the hydrogen atoms.

And since I don't think we're using the extra steam power step, that energy has to be directly converted to electricity.

One assumes if that if that transformation is interrupted, that energy has to go somewhere.

A battleship fusion reactor has to be several magnitudes larger than that in a backyard shed.

 

[Sigtrygg]

Doesn't seem quite right, considering the amount of energy involved.

The energy released from fusion reactions only released during the reaction. Take away the conditions necessary for the reaction and there is no energy.
Traveller fusion reactors use space magic to make the small reactors found on vehicles and ships, they have never described the energy inputs into the reactor...

To create a fusion reaction, you have to compress the hydrogen atoms.

Yup, and Traveller has magic gravitic fields...

And since I don't think we're using the extra steam power step, that energy has to be directly converted to electricity.

photovoltaics and thermocouples, I have yet to see a description of a fusion power plant using steam turbines... they could.

One assumes if that if that transformation is interrupted, that energy has to go somewhere.

The input energy switches off, the fusion reaction stops immediately, there is no eenrgy to go antwhere, or very little, the few micrograms of hot plasma.

A battleship fusion reactor has to be several magnitudes larger than that in a backyard shed.

So you get a gram of plasma, no big deal.

 

[Bryn the 2300AD guy]

Traveller fusion is explicitly protium fusion, which prettymuch rules out a plasma confinement reactor. I would suggest the gravity fields are probably compressing a tiny fraction of a gram, possibly inside an electrode a la cold fusion.

As for the amount of real energy, whilst a value has been given, it appears to not be realistic. From chemical reactions etc. 1 power point = 25 kW. This would make a 1 dTon reactor have a usable output of about 0.375 MWe, which is a sensible number.

Fuel use is 0.41 mg/s, which is 0.7% per second is converted is the energy equivalent to 150 kg of TNT. Clearly it is a lot less, and so it must be a very inefficient fusion process.

 

[gylesw]

Having done the maths previously it’s kind of a relief that we don’t have people saying a fusion power plant can be turned into a bomb.

I agree with the proton-proton fusion and gravetic compression to stellar densities idea.

What I have ruled IMTU is that a power plant can be set to ‘scuttle’ a ship. Basically the power planet will open an aperture in the confinement field that releases a short-lived pulse of plasma. This is normally enough to destroy and manoeuvre drive or Jump drive in the same compartment, perhaps the engineering compartment bulkhead, or maybe the hull. I’d allow the effect of a 10+ power plant roll in number of the above items damaged or destroyed. A simple 8+ would destroy the power plant. It also vents remaining fuel so get briefly burny.

 

[MasterGwydion]

Are nuclear missiles in Traveller fission or fusion?

 

[Sigtrygg]

You can get either type.