14 replies to this topic

[Burned_Follower]

Ok i know that according to the BT universe a battlmech uses a fusion engine.

But has the BT universe, novels, sourcebooks or otherwise expounded more on the technology and how it works?

I'm just a bit confused because when i googled how the nuclear power source works on an aircraft carrier for example, it works the same way a steam engine does(if i'm understanding it properly)...except radiation is the source of the heat instead of burning coals, oil, gas, etc.

I have also heard the term "cold fusion engine" thrown around in scifi circles but i doubt that a mech runs off of that since mechs do have heat problems when pushed too hard and explode like a small nuke when i play MWLL.

So when a Mech is fusion powered, does that mean nuclear, as in you can and will get radiation sickness if you are around enough mechs long enough? I do occasionally read BT novels and haven't heard of people struggling with radiation sickness after battle. If this is the case, then Solaris should be the "three mile island" of the inner sphere because of how many mechs probably to critical in the arenas. In a typical BT Mech vs Mech battle that i read in novels it usually goes like this: friendly mech meets enemy mech. Enemy mech gets destroyed. End of story. No radiation issues that follow.

Edited by XxDRxDEATHxX, 10 February 2012 - 03:08 PM.

[Kami Shinigami]

The main thing I would point out here is the difference between fusion & fission technology. Fusion technology would not blow up, when damaged... it would implode, if anything. The cases of games with Mechs using fusion engines blowing up is simply fan-gratification.

As far as the radioactive side of things, I can only guess that in the BTU they have come up with a way of building Nuclear Fusion Engines that do not produce radiation, similar in principal to the tactical nukes we have today (nuclear fission bombs with no fallout).

[Sug]

http://www.sarna.net...i/Fusion_Engine

Kapow!

[ice trey]

I can't really go too far into detail.

What I can tell you is that it supposedly runs on water, and just about any water source can be used, making it very easy to power a 'mech pretty much indefinitely. I can also tell you that it uses magnetic fields to keep the fusion plasma "Flame" from melting the inside of the engine, and that exposure to air will drown the plasma like water on a campfire - part of why MW4 style exploding 'mechs were a huge exaggeration for microsofts' idea of "Rule of Cool".

Beyond that, the lions' share of the info can be found inside of Techmanual, the rulebook that talks about how to build most anything in the Battletech universe using the Battletech rules. The only thing is that there's a limit. If we knew how to build fusion engines, we would have. Too much detail, and you find engineering students all in a huff about how unrealistic it is.

[Pht]

http://www.sarna.net...#Fusion_Engines

Quote

Fusion Engines

Fusion reactors generate huge quantities of electrical power by fusing light elements like hydrogen into heavier elements like helium. Nuclear fission, on the other hand, splits heavy elements like uranium into lighter materials.
The usual fuel used in modern fusion engines is normal hydrogen, the protium isotope to be specific. Historically other fuels were used in early fusion reactors. Anything from heavier hydrogen isotopes like deuterium and tritium, to the helium-3 isotope and even lithium. These heavier isotopes are easier to use, but the fusion engines that operated on them generated more nuclear waste than the modern fusion engines.
In modern fusion reactors, the normal hydrogen used for fuel is extracted from any number of sources - particularly water. Because of this is most military fusion engines include an electrolysis unit to extract hydrogen from water.
[edit] Containment and Power Generation

The fusion engine utilizes a super hot (tens of millions of degrees Celsius) ball of hydrogen plasma which converts into helium to create energy. In order to keep the plasma ball from melting the engine it is contained within a magnetic field. This is possible because plasma is electrically charged and thus it can be positioned and shaped by magnetic fields. There are magnetic fields inside the plasma ball and fields generated outside the plasma. In fact, the plasma never (normally) touches the walls of the engine. The reactor chamber is kept as a vacuum for heat insulation.
Power is extracted in two ways - the first is called "magnetohydrodynamics" or MHD. The shorter and mostly correct description of this process is that the plasma is like a dynamo, generating electrical currents in conductor loops that wrap around the reactor. MHD directly converts heat from the fuel into electricity. By operating at extreme temperatures MHD can exceed 90 percent efficiency in turning heat into electricity.
The second way of generating power is purely secondary and is called regenerative cooling. Regenerative cooling uses waste heat to generate power. Usually this is done with a closed-cycle gas or steam turbine. In a small way this is a part of the 'Mechs cooling system, even though this is not a part of the heat sink system proper. Regenerative cooling machinery is very different from purpose built heat sinks. The regenerative cooling system adds negligible volume to the engine, due to its using the existing plumbing of the engines cooling system. It would be quite useful if all the waste heat from an engine could be soaked up by these so-called "integral heat sinks," but practical limitations mean only so much energy can be extracted from this lower-quality source. Bigger engines make more waste heat and can have larger regenerative cooling systems, but most 'Mechs will use some conventional heat sinks placed elsewhere to handle the excess.

More at the link.

[Burned_Follower]

awesome! thanks for the replies and the link. I never really heard of Sarna.net until i started lurking around the forums on this website about a month a go. This will help me better understand things when i read the BT novels. I read a toal of ten BT novels over the years but i'm starting over with Ardath Mayhar's "The Sword and the Dagger". Yes i own a copy. Cost me 90bucks on Amazon when i got it about 5 years ago but worth every penny. Just started reading it again yesterday which got me thinking about fusion reactors. The book is a great read if you can actually find a copy.

[Zakatak]

Aircraft carriers/submarines use fission. Splitting Uranium-235 to extract about 0.3% of energy from atoms. When Uranium splits, neutrons fly off on there own. That causes radiation.

BTech uses fusion. Likely by splitting combining Deuterium and Helium-3 (non-radioactive) to extract 1.2% of energy from the atoms. Modern fusion isn't currently capable of producing sufficient power since we lack the materials and methods. Heat inside reactors is upward of 1,000,000 degrees unless BTech uses cold fusion.

[Euclid]

Kami Shinigami, on 10 February 2012 - 03:14 PM, said:

Fusion technology would not blow up, when damaged... it would implode, if anything. The cases of games with Mechs using fusion engines blowing up is simply fan-gratification.

Fan-gratification?!? Implode?!? Dunno 'bout that. It isn't a huge leap to imagine that breaching the containment of what, at a fundamental level, is basically an H-Bomb results in... an H-Bomb. H-Bomb's are known for their explosions, not implosions. Although I have to admit that I'm not too fond of the way every torso kill in MW resulted in the engine blowing up and it is just a wee bit on the flashy side.

To the OP: Radiation is a side effect of both fission and fusion. On the nasty fusion side of nuclear power is the long lived radioactive isotopes in the fuel that can take millenia to decay to stability. The byproduct of fusion is pretty much just a single burst of gamma (for Hydrogen fuel). Another nasty consequence of using fission is that unlike fusion, which will pretty much blow itself out (unless another form of energy is fed into the system like the sun's gravity), the only way to prematurely stop fission is to forcably disperse the fuel source.

Edited by Euclid, 10 February 2012 - 07:31 PM.

[Kami Shinigami]

Euclid, on 10 February 2012 - 07:16 PM, said:

Fan-gratification?!? Implode?!? Dunno 'bout that. It isn't a huge leap to imagine that breaching the containment of what, at a fundamental level, is basically an H-Bomb results in... an H-Bomb. H-Bomb's are know for their explosions, not implosions. Although I have to admit that I'm not too fond of the way every torso kill in MW resulted in the engine blowing up and it is just a wee bit on the flashy side.

To the OP: Radiation is a side effect of both fission and fusion. On the nasty fusion side of nuclear power is the long lived radioactive isotopes in the fuel that can take millenia to decay to stability. The byproduct of fusion is pretty much just a single burst of gamma (for Hydrogen fuel). Another nasty consequence of using fission is that unlike fusion, which will pretty much blow itself out (unless another form of energy is fed into the system like the sun's gravity), the only way to prematurely stop fission is to forcably disperse the fuel source.

H-Bombs (along with any other nuclear bomb) are fission based. Not fusion. Fusion does not explode. Fission does. Most of what we can put into actual use with today's technology is fission based nuclear reactions.

Read some of the other posts here; there aren't many. The radiation depends on the type of cells used. Please do some research before contradicting people.

[Euclid]

Not trying to contradict here. Just breaking things down to some basic principles. Yes H-Bombs are fusion/fission combinations. Because it takes a **HUGE** amount of energy to initiate the fusion process (say like the energy of a fission bomb or the sun). That's why inventing cold fusion would net you billions of dollars right now and is a Sci-Fi answer to the future's power needs (anti-matter being another that immediately jumps to mind).

Fusing is the process of joining together, fission breaking apart. On this topic what is getting fused and or fissioned are atomic nuclei. For elements greater than the atomic number of lead energy is released as a nucleus is split, conversely energy is released when two nuclei less than the the atomic number of lead are joined. (I'm still fascinated by the fact that any element heavier than lead is the result of a supernova.) Both result in energy released, ie an explosion. What do you think would happen to the sun, whose source of EM energy is fusion, if it weren't for gravity? What do you think a supernova is exactly?

Again, not trying to contradict. Just breaking things down into what works for Sci-Fi.

EDIT: Since everything now days is links or it didn't happen: http://en.wikipedia..../Nuclear_weapon .
And since I knew/acknowledged that H-Bombs are actually fusion/fission hybrids I will just quote the part that I want to emphasize. Particularly "a fission weapon is required as a "trigger" for the fusion reactions. Remove the need for a trigger, ie cold fusion, and viola. Free energy.

Such fusion weapons are generally referred to as thermonuclear weapons or more colloquially as hydrogen bombs (abbreviated as H-bombs), as they rely on fusion reactions between isotopes of hydrogen (deuterium and tritium). However, all such weapons derive a significant portion, and sometimes a majority, of their energy from fission. This is because a fission weapon is required as a "trigger" for the fusion reactions, and the fusion reactions can themselves trigger additional fission reactions.

Edited by Euclid, 10 February 2012 - 10:06 PM.

[Lycan]

Can't offer any more, or better, input then what has already been said.

Only thing i can say is that even though the Fusions reactors on a mech probably wouldn't explode, I still think it's extremely cool that they do.

[pesco]

re exploding fusion reactors:

the way my rudimentary (i'm no physicist either) understanding goes, well there's a whole lot of thermal energy in your plasma ball (or torus or what have you) all pressed together really tight by strong magnetic fields. very strong fields. so if you break it, i.e. your fields collapse, the whole bucket is very much going to explode. but there won't be any chain reaction. just a real big badaboom. how much of a fireball it would be, i don't know. probably not much from the reactor itself because the fuel (water) is not that flammable. and the plasma will probably cool off pretty fast while blowing apart the mech. so my guess would be you'd get a molten mech core, everything else ripped to shreds, a huge blast with a good amount of smoke, heat and also radiation, and secondary explosions from things like missiles and other ammo.

on radiation: the fusion process produces it in the form of short-lived gamma rays (as mentioned by Euclid above), that's the point. so if you break the shielding on your core, you'll get that leaking out as long as it's running. but the whole apperatus is still likely to be at least somewhat radioactive itself, because the gamma rays will "activate" the atoms of whatever the machine is made of (metals presumably). future materials science can be expected to lessen this effect by using things that are hard to activate, but it's probably fair to assume that it won't be wholly eliminated.

[daytrader]

Euclid, on 10 February 2012 - 07:16 PM, said:

Fan-gratification?!? Implode?!? Dunno 'bout that. It isn't a huge leap to imagine that breaching the containment of what, at a fundamental level, is basically an H-Bomb results in... an H-Bomb. H-Bomb's are known for their explosions, not implosions. Although I have to admit that I'm not too fond of the way every torso kill in MW resulted in the engine blowing up and it is just a wee bit on the flashy side.

To the OP: Radiation is a side effect of both fission and fusion. On the nasty fusion side of nuclear power is the long lived radioactive isotopes in the fuel that can take millenia to decay to stability. The byproduct of fusion is pretty much just a single burst of gamma (for Hydrogen fuel). Another nasty consequence of using fission is that unlike fusion, which will pretty much blow itself out (unless another form of energy is fed into the system like the sun's gravity), the only way to prematurely stop fission is to forcably disperse the fuel source.

Not quite sure what you mean by your last sentence, but a good way of prematurely stopping fission is by upsetting neutron balance. In order for a fission reaction to progress, energetic neutrons must collide with the fissile material. If you absorb/adsorb enough energetic neutrons, and that is accomplished by using an awesome neutron absorber material, e.g: boron, then the reaction will grind to a halt.

It's sort of been mentioned in the thread, but I should stress this for pro-nuke educational purposes anyway:
Neither nuclear nor fusion reactors can explode in nuclear explosions. The three major types of radiation are:
1) Alpha particles (helium nuclei) - Usually harmless since they can't penetrate human skin. May cause serious damage if inhaled/ingested though.
2) Beta particles (neutrons) - Highly problematic radiation that can generate gamma rays from neutron capture, and can "breed" radioactive atoms that will quickly decay, producing more gamma rays and neutrons.
3) Gamma rays (high-frequency EM radiation) - A gamma ray is deadly to all living tissue, but their only danger comes from their ability to knock an electron out of their orbits, ionizing the affected atoms. Their beauty comes from the fact that they don't interact with atomic nuclei, and therefore don't generate any radioactive junk what-so-ever. So if you were to go hunting with a gamma ray gun, your target would die, but their remains would immediately be safe to eat.

[Pht]

Well, if you want it from the horses mouth; right from the original source, directly on the topic:

Quote

Fusion engine explosions

This is an urban legend that will not die ... fusion engines going critical and exploding as mini-nukes.
The magnetic fields which contain the plasma also protect the plasma from the frigid (relative to the temperature of the plasma) reactor chamber walls. The fusion reactions in a BattleMech fusion reactor only occur in a very narrow band of temperature and pressure conditions. The hotter and the higher the pressure, the faster the reactions occur.
When heat is added to a gas, it expands. If it can't expand, its pressure goes up. Thus when the reactions spike a bit the plasma gets hotter and in turn it tries to expand. However, the magnetic fields aren't rigid so they will expand a little a bit, allowing the plasma ball to expand, which, in turn, lowers the pressure in the plasma - which cools the plasma and allows it to collapse to its normal size. There is a little bit of extra room in the reactor chamber for just this reason.


There are, however, other ways the reaction can cool down. If the magnetic fields don't do their job, the plasma ball can actually touch the frigid walls of the core which results in the plasma ball "blinking out." This barely even scuffs the walls of the reactor. When the plasma ball contacts with the frigid walls of the fusion reactor the fusion reactions in the plasma stop almost instantly because there is no stored thermal mass in the plasma ball. All of the heat in the plasma comes from active reactions. The multi-ton reactor walls (comparative to the plasma ball) have so much thermal mass that they can soak up the heat of the reaction and barely heat up. The plasma ball does not normally have enough thermal energy to do more than add a little heat to the walls of the engine around it.


Fusion reactors do on very rare occasions die in a spectacular manner, but the majority of those times isn't due to an exploding reactor.

What normally happens is that the reactor core is breached allowing a large quantity of relatively cold air into the vacuum of the reactor chamber which puts out the fusion reaction instantly... but in so doing, the intruding air in the reactor chamber soaks up all the heat and comes blasting back out in a white-hot blinding gout of flame. Considering that it takes massive damage to breach a reactor core so quickly that the safety fields can't drop down before something intrudes into the chamber... the visual end effect is that the 'Mech has very nearly been blasted in half, followed very quickly by a blinding fireball. This is a spectacular way to decommission a fusion reactor - a rampaging super-hot oxygen flash fire - but it is not a nuclear blast.


In the last instance it will happen that a MechWarrior will figure out that they can overcharge the engine, causing the plasma ball to heat up to an amazingly high temperature - far beyond their normal operating range - and than kill the magnetic field quickly, causing the extremely overheated plasma to hit the reactor walls which causes the reactor lining to explosively evaporate. The result of this is that the reactor is over pressurized, which causes a respectable explosion - but again, not a nuclear explosion.

http://www.sarna.net...gine_explosions

Edited by Pht, 26 February 2012 - 05:16 PM.

[Seabear]

Basically, what makes a fusion reactor go boom and rip a mech to pieces is not the thing that powers the mech. Hence, no radiation.