OOPS

ThinksMarkedly wrote:

Loren Pechtel wrote:That's going to require incredibly more force.

tlb wrote:That is clearly not a problem in the Honorverse: consider the enormous amount of energy needed to create a wedge.

That's what I was thinking. Under normal circumstances, using gravity to create fusion is going to require vast amount more energy than you get out of the fusion, unless you have so much mass helping you with that gravity. In that case, no amount of stealth is going to help you hide that mini-sun you're carrying in the belly of your ship.

We don't understand energy when hyperspace and the alpha wall are concerned in the Honorverse. Ships seem to get free energy from somewhere, and yet they still need fusion reactors with prodigious amounts of mass to sustain them for 6 months. So tlb's remark is valid.

Maybe they can harness hyperspace energy but only for gravitation, but to transform that energy into some other kind of useable energy requires the reactors. I just don't know why you'd use fusion for that: if you have a force capable of moving stuff, move some charged particles in a magnetic field.

I think ships only get free drive energy, they must pay the normal power bill of anything else.

I don't see why you say gravity must use a great amount of power. There are two cases: bombs and reactors. I don't think bombs have any vast inherent energy requirements, it must use as much power as is needed to compress the material but that's not really all that great. Anything beyond that is because the process isn't 100% efficient.

Reactors are more problematic as you have to keep containing the material.

cthia wrote:I didn't remember that ships' reactors use gravity - in the manner that they do. Recall that I was once invited to visit several nuclear power plants. Presently, they are designed to resist a complete failure of all systems for some significant amount of time far beyond "instant" destruction.*

For instance, the control rods use magnetism to keep them suspended above the reactor, and to lower them when needed. A complete failure of that system automatically uses gravity to drop all control rods. That is the meaning of fail-safe. If a system fails, it is still safe, for a reasonable amount of time.

You can design fail-safes to resist failure modes, you can't make a reactor that resists all forms of damage without bad results.

Look at Chernobyl. While I have seen some debate as to whether the power excursion actually went prompt critical or merely came very close to it the result was an energy release far beyond what could be contained. (And note that stronger containment wouldn't have helped--if you somehow kept it from going boom it would have kept on generating ever more power until the reaction poisoned itself. The power excursion would have gone into large h-bomb levels.)

Likewise, if you're containing a lot of very hot plasma you simply can't build a reactor that can guarantee to contain it against all forms of battle damage.

Loren Pechtel wrote:

cthia wrote:I didn't remember that ships' reactors use gravity - in the manner that they do. Recall that I was once invited to visit several nuclear power plants. Presently, they are designed to resist a complete failure of all systems for some significant amount of time far beyond "instant" destruction.*

For instance, the control rods use magnetism to keep them suspended above the reactor, and to lower them when needed. A complete failure of that system automatically uses gravity to drop all control rods. That is the meaning of fail-safe. If a system fails, it is still safe, for a reasonable amount of time.

You can design fail-safes to resist failure modes, you can't make a reactor that resists all forms of damage without bad results.

Indeed, your notion is part and parcel of my disgust with the Floating Chernobyl.

They are simply designed to allow enough time to mitigate the danger, instead of instant destruction.

Loren Pechtel wrote:Look at Chernobyl. While I have seen some debate as to whether the power excursion actually went prompt critical or merely came very close to it the result was an energy release far beyond what could be contained. (And note that stronger containment wouldn't have helped--if you somehow kept it from going boom it would have kept on generating ever more power until the reaction poisoned itself. The power excursion would have gone into large h-bomb levels.)

Likewise, if you're containing a lot of very hot plasma you simply can't build a reactor that can guarantee to contain it against all forms of battle damage.

A hydrogen bomb type explosion never could have occurred. The structure would have destroyed itself.

Loren Pechtel wrote:You can design fail-safes to resist failure modes, you can't make a reactor that resists all forms of damage without bad results.

Look at Chernobyl. While I have seen some debate as to whether the power excursion actually went prompt critical or merely came very close to it the result was an energy release far beyond what could be contained. (And note that stronger containment wouldn't have helped--if you somehow kept it from going boom it would have kept on generating ever more power until the reaction poisoned itself. The power excursion would have gone into large h-bomb levels.)

Well, it was beyond what the reactor shell could contain. From what I've read if the reactor had been within a containment dome like US reactors have, that multi-foot thick reinforced concrete dome would have been able to absorb the steam explosion that blew the reactor vessel apart. (And the area inside that containment dome is large enough that all the exploding steam coming out of the reactor will spread and cool enough that it can't rupture the dome). That dome would have prevented blowing all the radioactive parts of the explosion and meltdown all over the place. But instead the building around the Chernobyl reactor was basically a lightweight shell against the weather, and so anything strong enough to rupture the reactor's primary containment would easily blow through the rest of the building.

However Chernobyl had a lot less power concentrated than an Honorverse fusion reactor carries, so it's failure was far less explosive. Plus ships don't have room for the huge secondary containment enclosures that stationary power reactors have. (Even today a CVN doesn't exactly have the kind of containment dome that shore-side reactors do - so it its reactor suffers a meltdown or steam explosion it'll likely spread the radioactive debris and gases much further than if the same explosion happened in a US power station). So even if fusion plants down on the planets of the Honorverse have enormous and super strong containment facilities able to dissipate much of an uncontrolled failure a ship doesn't have room to install that same protection.

kzt wrote:

Galactic Sapper wrote:I think we can safely ignore the power drop-off from the distance around the reactor for intra-ship purposes. Regardless of how such power levels are achieved, we know from canon that a single fusion plant blowing can vaporize armor off the unshielded hull of ship hundreds of kilometers away (PNS Atilla and PNS Farnese in EoH), and that was under typical operating regimes and not a deliberate overload. Of course, we see something similar from the ejected core from Fearless in OBS as well, but that's a smaller plant and IIRC a sidewall is involved.

It’s really odd how David didn’t talk about the huge firestorm that enveloped all the habitable planets in the manticore systems when dozens of ship reactors lost containment at the same time when the stations were destroyed.

Inverse square law. What can boil the hull at 1000km is barely a flash at 1,000,000km and the battles were probably much farther away than that.

Jonathan_S wrote:Eh, he said in some posts here that the microfusion reactors on Mk16 and Mk23 missiles (and presumably also the ones Ghost Rider recon drones) had to be "jump started" with a packet of reactor plasma.

I don't recall him ever saying that full sized spaceship units were subject to the same limitation, so I wouldn't assume that a warship's reactors are incapable of started off auxiliary or stored power.

My thought, also. Missile and recon drone reactors are built small, realistically plasma will always be available and there's no reason for redundancy. Just because they can only be started by feeding them plasma doesn't mean there aren't other procedures available to cold-start a shipboard reactor.

Loren Pechtel wrote:Look at Chernobyl. While I have seen some debate as to whether the power excursion actually went prompt critical or merely came very close to it the result was an energy release far beyond what could be contained. (And note that stronger containment wouldn't have helped--if you somehow kept it from going boom it would have kept on generating ever more power until the reaction poisoned itself. The power excursion would have gone into large h-bomb levels.)

Likewise, if you're containing a lot of very hot plasma you simply can't build a reactor that can guarantee to contain it against all forms of battle damage.

cthia wrote:A hydrogen bomb type explosion never could have occurred. The structure would have destroyed itself.

Should that be atomic bomb, rather than hydrogen bomb; since we are talking about a fission reaction and not a fusion one?

cthia wrote:

Loren Pechtel wrote:Look at Chernobyl. While I have seen some debate as to whether the power excursion actually went prompt critical or merely came very close to it the result was an energy release far beyond what could be contained. (And note that stronger containment wouldn't have helped--if you somehow kept it from going boom it would have kept on generating ever more power until the reaction poisoned itself. The power excursion would have gone into large h-bomb levels.)

Likewise, if you're containing a lot of very hot plasma you simply can't build a reactor that can guarantee to contain it against all forms of battle damage.

A hydrogen bomb type explosion never could have occurred. The structure would have destroyed itself.

Read my post again. Of course it couldn't contain it--what I'm saying is that if you beefed up the containment with unobtainium to withstand the Chernobyl blast you would simply have held the reactor together during it's power excursion, the power would have gone ever higher until something gave or it's fuel was too poisoned to sustain the reaction.

The point is you build fail-safes to avoid a prompt critical, there's nothing you can do to make it safe if it does happen.

tlb wrote:

Loren Pechtel wrote:Look at Chernobyl. While I have seen some debate as to whether the power excursion actually went prompt critical or merely came very close to it the result was an energy release far beyond what could be contained. (And note that stronger containment wouldn't have helped--if you somehow kept it from going boom it would have kept on generating ever more power until the reaction poisoned itself. The power excursion would have gone into large h-bomb levels.)

Likewise, if you're containing a lot of very hot plasma you simply can't build a reactor that can guarantee to contain it against all forms of battle damage.

cthia wrote:A hydrogen bomb type explosion never could have occurred. The structure would have destroyed itself.

Should that be atomic bomb, rather than hydrogen bomb; since we are talking about a fission reaction and not a fusion one?

Yes, but read his post. He is talking about the "level" of the explosion.

Loren Pechtel wrote:Look at Chernobyl. While I have seen some debate as to whether the power excursion actually went prompt critical or merely came very close to it the result was an energy release far beyond what could be contained. (And note that stronger containment wouldn't have helped--if you somehow kept it from going boom it would have kept on generating ever more power until the reaction poisoned itself. The power excursion would have gone into large h-bomb levels.)

Likewise, if you're containing a lot of very hot plasma you simply can't build a reactor that can guarantee to contain it against all forms of battle damage.

cthia wrote:A hydrogen bomb type explosion never could have occurred. The structure would have destroyed itself.

tlb wrote:Should that be atomic bomb, rather than hydrogen bomb; since we are talking about a fission reaction and not a fusion one?

cthia wrote:Yes, but read his post. He is talking about the "level" of the explosion.

I realize that, but still thought that the H-bomb was considerably more energetic.