Starship Reactors and Dead Man Switches

[Praeothmin]

No, it wouldn't. Not when you need to have the core pushed out.

Actually, I believe small explosive release charges would do the trick, similar to the explosive charges that release the emergency pods in case of a ship wide failure.

[GStone]

Well, let's say you did do that (and I'm not being a smart ass about it, I'm actually curious and you can be sure I am because I mean what I say, not like some that will lie through their teeth when they say it).

Say you rigged the explosives to detonate once they no longer detect something, so they explode. There are probably things in place to hold the core where it's at. So, could there be enough push from the explosives, but not enough that it makes the core tip too far to one side, so it doesn't get caught on anything? The thing's several decks high.

[Knife1138]

No, it wouldn't. Not when you need to have the core pushed out.

Actually, I believe small explosive release charges would do the trick, similar to the explosive charges that release the emergency pods in case of a ship wide failure.

Considering it's space, why wouldn't a small explosive device to seperate the mechinism, and depressurizing the space be enough?

[Who is like God arbour]

OK, that ...

Maybe you should have read this. If I'm wrong, you could have shown me, where my mistake is. Then I could accept, that my further conclusions, basing on this assumption, are wrong too. But until now, I act on the assumption that I am correct.

Very well. Having looked, I will concede that modern fusion designs do use magnetic fields to contain the plasma. The point, though, is that if the field fails, the reactants won't explode if they contact the walls of the reactor. The failsafe I described is still perfectly valid.

... is a perfect example, why I dont like it, if my posts are torn apart and why I prefer an essay like answer. It happens always again, that, if only one sentence is quoted, it is taken out of context, or other statements, made before the quoted sentence, are ignored.

I have already argued this objection.

By the way, I think, it is wrong to assume, that, if antimatter is feeded into the reactor at only the rate, it is needed to maintain the desired power output, there would be no need for a warp core ejection system at all. It isn't enough to shut off the flow of antimatter in the event of a containment problem. The reaction of matter-antimatter release energy and exert pressure. These energy and pressure have to be contained by a containment field The energy and pressure in the reaction chamber doesn't vanish at once, only because there are no further matter-antimatter reactions. If the containment of the reaction chamber begins to weaken, one could stop the antimatter flow but nevertheless could be obliged to eject the warp-core because the energy and pressure in it doesn't decrease as fast as the containment is collapsing.

The same goes for fusion reactors. A huge problem today is not only to induce a constant fusion reaction, but to create a stabil containment field, therewith the reactor doesn't melt down due to its own released energy. But if the pressure and energy in such a reactor (from the 24th century) is high enough and suddenly released due to a failing containment, the consequence would be something, what I would describe as an explosion.

I have not said, that the reactant will cause an explosion, if it contact the walls of the reactor.

What do you think, why there are containment fields? To contain nuclear fusion reactions. The plasma in such an reactor will be heated to its operating temperature of greater than 10 keV (over 100 million degrees Celsius) [1]. I have no idea, what a pressure would there be in such a reactor. But even if the pressure is ignored, what do you think, how much time is needed for a plasma with a temperature of over 100 million degrees Celsius to vaporize its encompassing reactor, once the containment is collapsed?
And usually, I would say, that contained plasma with a temperature of over 100 million degrees Celsius would be under considerable pressure. If this assumption is correct, there will be an explosion, if the containment field is collapsed. The explosion power will depend on this pressure and the energy behind it.

The failsafe, you have described...

And, as I said, if you have a seal on your fusion reactor in a "safe" location (like a hatch to the outside of the ship) that will fail before the reactor actually explodes, the seal will break before the whole reactor goes, dropping the pressure and venting the hot gases inside safely out to space. It's a relatively simple failsafe.

• • and

Since fusion reactors don't require force fields to keep the fuel from contacting matter, it's a much simpler design. In a fusion reactor, if the pressure gets to high, you can just let it blow off an emergency hatch to release the pressure. With the loss of pressure, the fusion reaction would die, end of problem.

... has exact the problems, I have described already ...

And it is not possible to vent on the spur of the moment the internal pressure out to space. It would have to be channelled through pipes, which goes from the reaction chamber to and through the hull of the ship. But if I would be an engineer of a ship, I wouldn't build a shaft from the hull of the ship to the warp core. (Unlike another engineer, whose huge battle station could have been destroyed through such an emergency exhaust shaft) Another problem is, that these pipes would have to be included in the containment system too or would have to have their own containment system. Both, the containment system and the pipes itself could get damaged in a battle, especially because these systems are near the hull and therefore less protected than the warp core in the center of the ship.

• • and

I think, it is not so simple. The reaction champer is completely encased in the containment field. There would be no pressure on a hyphenation point unless the containment field is collapsed. But then, it would be to late, to vent the gases safely out to space.
If the field around the reaction chamber is weakening, it would be necessary to open a small hole in the containment field, through which the hot gases can be channelled in the pipes, which would have to need their own containment field and are going through the ship to and through the hull.
That doesn't seems to me as a relatively simple failsafe, notwithstanding that it is an active fail-system and not a CR fail-safe system (or how ever you want to call it). I would even allege, that it is outright dangerous - if not impossible - to open a hole in a destabilised containment field. It could collapse at once.

... Anyway I have not seen an objection to this arguments.

The M/AM chamber has an entirely different problem. One of the reactants, the antimatter, most definitely will explode if it comes into contact with the chamber wall. Consequently, you have a more serious safety problem that requires you to quickly get rid of either the antimatter or the entire chamber of your field starts to fail.

I don't see such an entirely different problem. The containment field of the warp core has to not only prevent the antimatter to contact the walls of the reaction chamber but has to resist the huge pressure and energy, which is released in the reaction chamber. The real problem is the latter and not the first.
What do you think, why there was never real problems with the antimatter pods on the Enterprise (as far as I can remember)? I would say, because to contain antimatter, which is not under considerable pressure, is far easier than to contain the hellfire in the warp core reaction chamber. In whole Star Trek, there was only problems with the antimatter pods under extraordinary circumstances and even then very rarely.

• • Antimatter pod
    Antimatter pod are special magnetized self-contained storage units which contain un-reacted antimatter fuel for a starship. Antimatter pods use an antimatter containment field to isolate the fuel within from contact with normal matter which would cause it to be annihilated with catastrophic ramifications. (Star Trek: The Next Generation Technical Manual)
    
    Incidents
    In 2365 the USS Yamato's antimatter containment field in their antimatter pods failed, causing the destruction of the ship. (TNG: "Contagion")
    
    In 2366 the non-corporeal Koinonians drained antimatter from the containment pods to use it as energy to create their replica of Marla Aster. This was stopped by increasing the shield harmonics to match the antimatter containment effectively severing the Koinonian beam. (TNG: "The Bonding")
    
    Later that year, radiation that had leaked from Doctor Nel Apgars station in orbit of Tanuga IV threatened the Enterprises antimatter pod. If the radiation had surged in or near them, it would have destroyed the ship. (TNG: "A Matter of Perspective")
    
    In 2369, Commander Benjamin Sisko ejected the antimatter pod of the USS Yangtzee Kiang just before the runabout crashed on a planet in the Gamma Quadrant. (DS9: "Battle Lines")
    
    Later that year, while traveling back to the Enterprise by Runabout, the starboard antimatter pod has been completely drained, despite the fact that there was no leak and all of the other engine systems were fully operational. It turned out that the runabout had entered a region of temporal fragments that made the antimatter pod work longer then the rest of the shuttle had. (TNG: "Timescape")
    
    In 2372, while Captain Janeway and Commander Chakotay were trapped on a planet, Lieutenant Commander Tuvok had to fight off several Vidiian ships. To do so, he released an antimatter pod and let it get close to the ships, and then fire a photon torpedo at it. (VOY: "Resolutions")
    
    Antimatter pods are self-contained units, their containment fields continuing to function even after being ejected from the starship. (VOY: "Resolutions")
    
    Background
    We can assume that antimatter pods are self-contained and survive some sorts of disasters aboard starships -- such as the destruction of the starship, uncontrolled entry into an atmosphere etc. This is because vehicles in the Star Trek universe do not consistently explode on every single occasion a vessel is catastrophically damaged. It is probably safe to assume that each pod has its own battery, other power source to maintain the containment field, or some kind of post-exhaustion flush method. This way, it is believable that a free floating antimatter pod from a destroyed starship, or a pod remaining in a derelict hulk, could remain intact until such a time as all of the antimatter within was expended.

Oh, come on. Failsafes have to work under abnormal conditions; you build them to prevent disasters under unusual circumstances. The type of failsafe Mike and I described would have prevented the explosion of the ship in all three of the situations in which a Galaxy-class blew up due to a warp core breach.

Yes, but the ship has to work under abnormal conditions too - contrary to a terrestrical reactor. The problem with a CR fail-safe system (or how ever you want to call it) is, as I have already described, that it would be released already, although it is expected from the ship to still work. That's the purpose of a CR fail-safe system (or how ever you want to call it): to be released in abnormal conditions.

Again, this debate has come full circle. There is no real progress.

[GStone]

No, it wouldn't. Not when you need to have the core pushed out.

Actually, I believe small explosive release charges would do the trick, similar to the explosive charges that release the emergency pods in case of a ship wide failure.

Considering it's space, why wouldn't a small explosive device to seperate the mechinism, and depressurizing the space be enough?

Because the core's many decks high and it isn't sitting on the edge, you have to make sure it doesn't tilt and get caught on something. You could say that the air and gravity fields inside the ship might simulate earth conditions for a passive fall, but that isn't gonna help. Not every square inch of volume is gonna have the gravity field, especially the outermost part of the hull.

If you have to worry about depressurizing the section without effecting the rest of engineering and the other decks the core goes through, that means a partially active system, which goes against the dead power switch idea. DPS for ships can never be totally passive.

[Who is like God arbour]

If you have to worry about depressurizing the section without effecting the rest of engineering and the other decks the core goes through, that means a partially active system, which goes against the dead power switch idea. DPS for ships can never be totally passive.

That's another good objection.

But it's not only that. I have already described another problem:

Furthermore, I doubt, that the ejection system of the warp core could be constructed as a CR fail-safe system. You can't on the spur of the moment eject the warp core. There a pipes and power supply line from and to the warp core, which have to be sealed. Through some of these pipes is anti-matter flowing. These pipes have to have their own containment and aren't closeable as easily as a water tap. But a CR fail-safe system is so "dependable" because it is so simple designed. The more complex it is the more accident-sensitive it is.

You wouldn't want to eject the warp core only that antimatter, which usually would flow in the warp core or that the energised plasma from the electro-plasma distribution network, which usually would be channelled from the warp core to the warp nacelle pylons, can flow in the engine room, if the warp core is suddenly not there anymore. That would destroy the ship too. To prevent that, the pipes and power supply line from and to the warp core have to be sealed. I don't see, how all that can be done, by a passive CR fail-safe system.

[GStone]

Not only that, you'd need a way to draw the antimatter back into the pod. The power circuits probably get shut off by some kind of circuit breaker that's tripped when they start to disconnected the core. To draw the antimatter back in, there might be a type of mini-tractor beam that can keep it from touching the feed lines, if containment in these eed lines is lost.

But, ENT didn't have tractor beams, well the Earth ships didn't. So, I wonder what kind of safeguard they had in place for that tpe of situation?

[GStone]

The only thing I can think of at the moment for what ENT would have to draw the antimatter out would be an independent particle accelerator grid inside the feed lines that would kick in to pull it back.

[Praeothmin]

Because the core's many decks high and it isn't sitting on the edge, you have to make sure it doesn't tilt and get caught on something.

You could easily do that by attaching it to guides that go from the top to the bottom of the shaft, and it would move on frictionless bearings.

But

You can't on the spur of the moment eject the warp core. There a pipes and power supply line from and to the warp core, which have to be sealed. Through some of these pipes is anti-matter flowing. These pipes have to have their own containment and aren't closeable as easily as a water tap. But a CR fail-safe system is so "dependable" because it is so simple designed. The more complex it is the more accident-sensitive it is.

That might be a little more problematic... :)

But I still think that a failsafe that ejects individual antimatter pods would be good, in the case that 1 pod ruptured.

But that brings up one question:
Do ISDs have such a system?
What happens if they lose the containment field in their Hypermatter reactor?
It goes boom, and they have no chance of ejecting it?
Because, if that is the case, then they would need to redesign the Imperial ships as well...

[Who is like God arbour]

But I still think that a failsafe that ejects individual antimatter pods would be good, in the case that 1 pod ruptured.

Now to the point, why I think, that it would be disadvantageous to employ a CR fail-safe system wherever possible in a star ship.

There is no doubt, that it would be better, if the warp core or the anti matter pods are ejected, before they explode in the ship. The question would be, what fail safe system would be advisable for this task.

I think, that a CR fail-safe system would be disadvantageous because they tend to be released in unfavourable situations, in which a star ship - contrary to a terrestrical reactor - can get but have to continue to functioning nevertheless. They don't have damage-tolerance or fault-tolerance (other construction principles), which is especially needed by a star ship in a battle.

• • For example, if the Enterpise in Star Trek II would have had CR fail-safe systems, they would have lost at least their warp core and maybe even all anti matter pods, after the warp core was damaged and the ship hast lost its main- and secondary-power.
    If the Enterprise in TNG "The Last Outpost" or "The Booby Trap" would have had CR fail-safe systems, they would have lost their warp core and all anti matter pods, after their energy was drained.

We have seen in many episodes, that a containment field usually doesn't lost its integrity suddenly. There is usually enough time to prevent its collapse. We can conlude, that there is a capacitor or some other systems, which maintain the containment field. Therfore, as we have seen, the crew has in most cases enough time, to repair the damage. An ejection would be necessary only if the crew fails to repair the damage and the total collapse of a containment field is not preventible anymore. But that must be decided, either through the computer or through the operator.

• • For example, if the Enterprise in the TNG episode "11001001" would have had a CR fail-safe system, the warp core would have been ejected in the star base. But because it has had no such disadvantageous system, they had enough time to evacuate the Enterprise and program the auto-pilot to fly the Enterprise away. (We don't know, wether the computer should have ejected the warp core, after the Enterprise has left the star base and has arrived at a safe dictance.)

Furthermore, I doubt, that the ejection system of the warp core could be constructed as a CR fail-safe system. You can't on the spur of the moment eject the warp core. There a pipes and power supply line from and to the warp core, which have to be sealed. Through some of these pipes is anti-matter flowing. These pipes have to have their own containment and aren't closeable as easily as a water tap. But a CR fail-safe system is so "dependable" because it is so simple designed. The more complex it is the more accident-sensitive it is.

That's why I think, you need an active, but dependable ejection system.

Sure, there it the danger, that the ejections system itself fails and in an emergency, the warp core is not ejectable anymore. But an engineer has to ponder the different probabilities and measures of damages. And I think it is better, that the crew of a ship has the last word, wether essential systems are shut off or even ejected with the minimal risk, that the ejection system could fail than that for example in a battle the CR fail-safe systems are released due to damage, which is in a battle very probable although the crew could have maybe repaired the damage and continued the battle.

Another question would be, if the active ejection system itself could be improved, that there are not so many malfunctions. (I think, that this is realy stupid written from the authors of the diverse episodes.) But to design a CR fail-safe system instead would be a bad solution.

I provide the following quotation from TNG "Contagion":

• • GEORDI
    Sensor recordings reveal that what we witnessed was an uncontrolled and catastrophic matter/antimatter mix. The magnetic seals between the chambers collapsed --
    
    PICARD
    That's not possible.
    
    GEORDI
    Yes, sir, it is, but a highly improbable series of events has to take place before such an occurrence can result.
    
    PICARD
    Explain.
    
    GEORDI
    In the event of a breach of seal integrity there is an emergency release system which dumps the antimatter.
    
    DATA
    Apparently such a dump began, was then halted, and the containment
    seals were dropped. There was still sufficient antimatter present to lead to the result we observed.

As I understand it, such an event was highly improbable. Sure, a CR fail-safe system would have prevented it. But as a basic principle, it wouldn't be needed because such a situation wouldn't normally happen.

As I have already asked earlier:

• • There was how many warp core breachs in whole Star Trek with (ENT: 97, TOS:80, TNG:176, DS9:173, VOY:168) 694 episodes and 10 movies? How many was due to a battle or some other exceptional circumstances?

For me, it seems, that Star Trek Engineering is not idiot engineering. They have decided, to take some mini-risks substitutional for important vantages.

A terrestrial reactor is a whole other question because, as it is obviously, it has total other requirements to security, damage-tolerance and reliability. As I have said already, if a terrestrial reactor is shut down, nobody has to die. Other reactors would undertake the electricity supply. But if it explodes, many people are affected by this. That's different for a star ship.

A star ship has also to work under abnormal conditions - contrary to a terrestrical reactor. The problem with a CR fail-safe system (or how ever you want to call it) is, as I have already described, that it would be released already, although it is expected from the ship to still work. That's the purpose of a CR fail-safe system (or how ever you want to call it): to be released in abnormal conditions.
The danger is, that in battle, in which the ship is damaged (or other, already listed or similar extraordinary circumstances) several or all CR fail-safe systems (or how ever you want to call it) could be released.

That's why I think, it would be better, if a computer ...

• • Galaxy-class starships in the 24th century had a system of seven independent computer safety locks to prevent antimatter containment from being breached, assuming that there was no damage to the warp core components.

...or a operator decides to eject a damaged and not repairabel antimatter pod or warp core.

[Jedi Master Spock]

But that brings up one question:
Do ISDs have such a system?
What happens if they lose the containment field in their Hypermatter reactor?
It goes boom, and they have no chance of ejecting it?
Because, if that is the case, then they would need to redesign the Imperial ships as well...

According to the ROTJ novelization, Star Wars reactors can go boom. According to the ROTS novelization, however, a fuel explosion won't total the ship. Ejecting fuel doesn't seem to be an option for them AFAIK, but IMO, most Trek ships are worse off in regard to this problem.

[GStone]

But that brings up one question:
Do ISDs have such a system?
What happens if they lose the containment field in their Hypermatter reactor?
It goes boom, and they have no chance of ejecting it?
Because, if that is the case, then they would need to redesign the Imperial ships as well...

A star ship has also to work under abnormal conditions - contrary to a terrestrical reactor. The problem with a CR fail-safe system (or how ever you want to call it) is, as I have already described, that it would be released already, although it is expected from the ship to still work. That's the purpose of a CR fail-safe system (or how ever you want to call it): to be released in abnormal conditions.
The danger is, that in battle, in which the ship is damaged (or other, already listed or similar extraordinary circumstances) several or all CR fail-safe systems (or how ever you want to call it) could be released.

That's why I think, it would be better, if a computer or a operator decides to eject a damaged and not repairabel antimatter pod or warp core.

You know, I can just image the entire lower rear of an ISD disconnects from the ship. A couple of the pieces disconnect from the larger part and we see several tiny spots glow from inside the 'hole' in the back of the ISD, pushing it forward. Then, the ISD jumps to hyperspace right before the ion engines and the reactor explodes. It'd be a cool visual.

[Who is like God arbour]

A complement to this:

What do you think, why there are containment fields? To contain nuclear fusion reactions. The plasma in such an reactor will be heated to its operating temperature of greater than 10 keV (over 100 million degrees Celsius). I have no idea, what a pressure would there be in such a reactor. But even if the pressure is ignored, what do you think, how much time is needed for a plasma with a temperature of over 100 million degrees Celsius to vaporize its encompassing reactor, once the containment is collapsed?
And usually, I would say, that contained plasma with a temperature of over 100 million degrees Celsius would be under considerable pressure. If this assumption is correct, there will be an explosion, if the containment field is collapsed. The explosion power will depend on this pressure and the energy behind it.

It is correct, that fusion usually cannot run out of hand. But if the fuel supply is closed, the reaction is continued for a few seconds nevertheless. It doesn't stop at once. [1].

The International Thermonuclear Experimental Reactor in Cadarache, France will have one half gram of deuterium/tritium fuel [2], which will be heated to its operating temperature of greater than 10 keV (over 100 million degrees Celsius) [3]. Maybe someone can calculate, how many damage that can create, respectively how much matter could be vaporized therewith.

• • But that is only an experimental reactor. It is a research project designed to demonstrate the scientific and technological feasibility of a full-scale fusion power reactor. ITER is designed to produce approximately 500 MW (500,000,000 watts) of fusion power sustained for up to 500 seconds (compared to JET's peak of 16 MW for less than a second). [4] I think, one can assume, that a future fusion reactor would have more plasma to release more energy.

Furthermore, in the magnetic approach, strong fields are developed in coils that are held in place mechanically by the reactor structure. Failure of this structure could release this tension and allow the magnet to "explode" outward [5].

In addition, most reactor designs rely on the use of liquid lithium as both a coolant and a method for converting stray neutrons from the reaction into tritium, which is fed back into the reactor as fuel. Lithium is highly flammable, and in the case of a fire it is possible that the lithium stored on-site could be burned up and escape. In this case the tritium contents of the lithium would be released into the atmosphere, posing a radiation risk [6].

Fact is, a fusion reactor is not inherent safe and would need fail-safe systems.

[Who is like God arbour]

According to the ROTJ novelization, Star Wars reactors can go boom. According to the ROTS novelization, however, a fuel explosion won't total the ship. Ejecting fuel doesn't seem to be an option for them AFAIK, but IMO, most Trek ships are worse off in regard to this problem.

Why only according to the ROTJ novelization? In three of six movies, a Star Wars ship reactor is exploded after an attack [Episode 1, 4 and 6].

Not the torpedos have had such a explosion power. The reactors are detonated, after they were damaged by the torpedos.

Compare this to Star Trek with (ENT: 97, TOS:80, TNG:176, DS9:173, VOY:168) 694 episodes and 10 movies?

[Who is like God arbour]

You know, I can just image the entire lower rear of an ISD disconnects from the ship. A couple of the pieces disconnect from the larger part and we see several tiny spots glow from inside the 'hole' in the back of the ISD, pushing it forward. Then, the ISD jumps to hyperspace right before the ion engines and the reactor explodes. It'd be a cool visual.

How could it jump to hyperspace, if it has just lost it's main power? I have always thought, that would need huge amounts of energy.

Is there a canon evidence, that they have a battery backup, which is sufficient for a hyperspace jump?