I'm surprised you spend that much time with these. Alternative.nu looks like an online MTV station, and last I checked, the Winamp stations were simple video loops of stuff that people thought would be cool to put online. Has something changed?
I've heard other people talk about Internet TV, but I haven't seen any concrete examples yet. And sites like IFilm are really just collections of clips. What Internet TV stations do you watch?
Modern nuclear reactors are pretty safe. Modern reactors are actually designed so that the mere act of a melt-down would cause the reaction to stop in much the same way a fuse cuts power in a surge. If something went wrong with the reactor or the pump, the engine should be designed to simply shut down.IIRC, the original author even pointed out that a failure of one engine would still allow the others to power the craft into orbit.
So safety wise, I can't really come up with a better design. Nuclear engines has enough power at their disposal to bring a craft up to orbital speed much more gently than an atmospheric technology like Ramjets and Scramjets. A structural failure of any sort could be disastrous in a scramjet. Not to mention the high possibility of loss of control.
It's interesting to read accounts from SR-71 pilots. They said that taking the thing hypersonic was a difficult feat as the craft wanted to buck at the pressures being applied. As a result, they had to fly within an exceedingly constrained flight envelope. If they failed to maintain that flight envelope, the craft could do anything from completely lose control, to twist itself into an unflyable shape. Titanium is strong, but the pressures applied at Mach 6+ are much stronger.
In any case, this is all moot. Whatever transportation technology gets chosen will be refined through use until it is as safe as a modern airline. Heck, did you know that the first jet planes for commuters had to be shut down because they were falling out of the sky? It turned out that the square windows on the planes were putting stress on the airframe. After enough flights, the airframe would rupture and the whole plane would go down. They fixed the problem by switching the the curved windows that you see in airplanes today.
You know, friendly fire isn't friendly at all. I appreciate people correcting me because it improves my education on the matter. And education is what this entire story is about. I wouldn't have posted it otherwise.
Don't think for a minute that I didn't realize that this story would bring just about every environmental wacko and uninformed person to the surface. But I was hoping that by exposing them to positive thinking about nuclear power I could get at least a few people to open their eyes and say "Look what nuclear power can do for us!"
The time has certainly never been better. About 60% of people are in favor of nuclear power and about 80% are in favor of renewing the licenses for existing nuclear plants. And despite that truth, I get attacked by EDUCATED people when suggesting that nuclear power could change everything. And I mean everything from your cell phone, to your laptop, all the way up to space exploration. We just have to stop being afraid of it.
Am I crazy? Perhaps. But I never liked to bullshit around. I will bash my way through every anti-nuclear roadblock in existence if it means bringing the benefits of nuclear power to the world.
The only reactor I'm aware of having a melt down is Chernobyl and that was a fucking *huge* issue.
Was it? About 40 people were killed, and the other three stacks continued to operate for a decade or two afterwards. It's really not much worse than any other industrial accident.
As for why it was a big deal, well that's a different story. For one, the public was still freaked about the cold war. Nukes were a thing to fear and would wipe out the entire world. Secondly, the people running the plant caused the problem by trying to use unqualified workers to do a safety test in the middle of the night. The Russian government covered this little fact over. Thirdly, the Russian government didn't do much cleanup beyond sealing the blown reactor. As a result, quite a bit of radioactive material polluted the nearby area and caused a few health problem. (Not all that different from a major chemical spill.)
You realize that you're about the TENTH person to tell me this? If you'd taken the time to read other posts you would have seen my response where I said I was using "critical" in the colloquial sense of the term. Yes, it's not correct and I'll be sure to use "prompt critical" in the future.
Now would you like to argue that a "prompt critical" situation generally results in something much worse than a large boiler explosion? And would you like to explain how I was trying to "scaremonger"? I mean, I was only trying to demonstrate how safe nuclear reactors actually are. Or did you simply read "critical", think "this guy knows zero, therefore he's an environmentalist wacko! Get him!" Do you really think that will help improve public perception?
BTW, to everyone who responded. Thank you for your corrections. I'm still pretty new to nuclear science, so my explanations may be slightly off at times. I'm glad to know that there are some of you still out there who can be polite when correcting me.
Don't you think it's a little presumptuous to say that I don't know what I'm talking about when you yourself admit to not understanding half the spectrum I'm referring to?
Besides, I said before that eCos probably has a market. It just isn't a big one (i.e. niche).
*sigh* First off, I'm not a nuclear physicist, so you have to cut me some slack. Second, I was referring to "critical" in the colloquial sense of the term. i.e. The melt-down reaches a point where an explosion happens. Not being a nuclear physicist, it's a bit difficult to know about things like "prompt critical".
Actually, I take that back. It probably came up in my private studies, but it's one of those things that tends to slip your mind when you have 20+ years of television crammed into your head. "You should run before the reactor reaches critical! Where can I run? There's no way to escape the blast!" Blech. I should have watched less TV growing up.
I'm actually speaking as an ISV who's done a lot of work to try to add as much support for RedHat as possible. Obviously I want to deliver the best experience to my customers possible, but that's not really possible when installing icons in the foot menu causes them all to disappear! And you know who that hurts? Both of us. RedHat will catch some blame for being a crappy OS, and I will catch some blame for not providing a good user experience.
Well pardon me for posting the story in the first place. I didn't realize how little the Nuclear Space servers could take and scrambled to post mirror links in a hurry. And I at +2 so the mirror would get seen. I'm hardly looking for Karma. I'm already capped and in no danger of dropping.
It is when they use a not-yet-released-for-public-consumption-because-it 's-still-under-development kernel. Would it have killed them to use the stable kernel?
And it is their responsibility as an OS manufacturer to make sure the hardware works. The fact that they gave no consideration to that was a bit upsetting.
Allow me to rephrase. NERVA got up to 75,000 pounds of thrust out of the TEST rockets. The GCNR rockets are far more efficient, plus we can boost efficiency by use of particle accelerators on the plasma. Thus we can get MORE THRUST with THE SAME REACTION MASS that is used for chemical thrusters.
Think of the nuclear rockets as ultra-powered chemical rockets. Somehow we've managed to get the hydrogen to higher velocities than was previously possible with a simple chemical reaction.
BTW, Force = Mass * Velocity2. So more velocity at the expense of mass will improve our thrust. Obviously there's an upper limit to how much velocity we can obtain, so we need to throw more mass. But if you consider that a nuclear engine can throw the same amount of mass as a chemical engine (minus some "light" electrons lost in plasma conversion), then we have greater overall force coming from our nuclear than our chemical reaction. Although, to be exact we're both throwing and pulling against the plasma. First we create the plasma which is exhausted (throwing). Then we use EM accelerators to pull on the plasma on the way out. The "pull" transfers that much more energy from the mass to the craft.
That being said, I am NOT a rocket scientist, so I can't give you exact numbers. However, the article I linked to in the story does give quite a few numbers, and a bit of googling will produce even more exact numbers. (I've seen some right down to the force per molar mass on usenet. Since I wasn't going to be building one of these things myself, my eyes kind of glazed over at that.)
It has been theorized that if this happens, the molten core will burn through the earth until it reaches water
Umm... are those the same guys who thought a tether would be a good way to test the Pluto Project? (A mach 3 unmanned missile.) If the core melts, it's going to start merging with other materials. Those other materials will begin to shield against the neutrons, thus preventing the reaction.
Trust me, there's plenty of "hot" (both radioactive and temperature wise) stuff at the core of the earth.
Upon contact with the core the water will turn into steam and create what is in effect a steam cannon, blasing the core back up the hole and showering bits of the core for miles around.
Assuming you're correct (which really assumes an amount of runaway material that wouldn't be available), rockets are launched over the Atlantic for just this reason. Any unpredictable event will have as good as unlimited space for whatever destructive forces it expends. "Miles" may seem like a long distance, but in this situation we've got plenty of them.
Now, if say a nuclear disaster happens, say only a mere 5000 ft. in the air, how far will the nuclear fallout go in a worst case scenerio?!
I don't have actual numbers, but not far at all. An explosion of a nuclear rocket would produce about the same results as a chemical explosion. i.e. The remaining rocket and debris would drop to the ocean. As for a melt-down, it's like I said before. A melt-down would produce more thrust instead of an actual explosion. BTW, plutonium and uranium are pretty tough materials. An explosion really wouldn't be sufficient to turn them to powder. An uncontrolled reentry would be more of a concern. But that's where building it in a "black-box" type of shell would help mitigate the problems.
The boosters have more than enough thrust to weight ratio. (ISP of 3000-5000) The problem as I've heard it, is that a much larger thrust to weight ratio is necessary to initially get off the ground. Chemical rockets apparently overburn for the first few seconds to deliver a few million pounds of thrust that get the liftoff started. I haven't managed to verify any of this yet, but that's my understanding.
If going "critical" means that it has gone beyond the safeguards and is melting the containment safeguards (which is what I meant..) then who's to say the pumps (or any other piece of equipment) wouldn't just melt?
Because the Turbopumps are in a different part of the craft. Did you read the article? Turbopumps push a steady stream of fuel from the tanks to the core where the core heats the material to PLASMA. Don't suppose you know how hot plasma is, do you? I'll try to explain it this way: The reactor is DESIGNED to run under what would be considered melt-down conditions in a normal reactor. More heat from the reactor means more energy transfered to the fuel, which means more thrust. If you cut the thrust, the backend of your rocket will melt and fall into the ocean. The ocean will provide a new moderator that will stop the reaction completely. The reactor will still be contained in its shielding, so little to no radiation will be exposed to the underwater environment. (Not that underwater volcanos don't already put out enough of that.)
But that's all besides the point, the point was, if it DID go critical, and it DID explode, that would be inherently WORSE then if the shuttle just blew up.. You said: "Thus the containment itself can produce a big explosion"
Doesn't that one statement agree with what I'm saying?!
No. Because you took two different designs and equated them. Nuclear engine != Nuclear powerplant. A powerplant exists under pressure. It can only operate within certain heat tollerances before a boiler explosion (and it IS a boiler explosion) happens.
A nuclear engine exists in a state where ALL the heat is being transferred to fuel. More heat is actually a GOOD thing in the engine as it provides more thrust. The problem with a runaway reaction (which doesn't just happen by itself, sorry to say) is control. You're now sending your astronauts on a trip to the moon when all they wanted was to achieve orbit. That's a problem. In many ways that's less of a problem than a failed chemical booster which would simply explode, or fail, or just about anything else. Assuming the craft survived the initial failure (not likely), a chemical booster helpfully drops you back to Earth at terminal velocity, on an unknown vector.
With a little education, you should be MORE scared of chemical rockets than nuclear ones.
It has nothing to do with the tonnes of nuclear waste produced for which the only solution seems to be "put it down a large hole, that'll do" then?
Nuclear waste is a big lie. Here's how it breaks down: we have reactors that can reprocess nuclear waste into useful fuel for reactors (e.g. the "breeder" reactor). However, doing this would require that more companies get involved with dealing with nuclear materials. Despite the fact that 99% of the "nuclear waste" is unsuitable for radioactive weapons of any kind (including "dirty bombs"), the US government has decided that it's safer to bury the stuff and cover it with cement. They apparently think that will somehow stop terrorists from developing a nuclear bomb. Go figure.
And would dispersal be greater if the nuclear reactor went critical?! Thought so...
Here's where education is important. Do you understand what "going critical" is? Very specifically, it's a build up of heat from a "melt-down". (A "melt-down" being when a nuclear reaction gets out of control and produces excessive amounts of heat.) Usually reactors are highly contained units. All that extra heat builds up pressure that has to go somewhere. Thus the containment itself can produce a big explosion. Still, it's more like an industrial boiler exploding than a nuclear bomb. The only radiation is from any radioactive material that gets ejected. (Usually not much, and cleanup isn't too large of an issue.)
Now in a nuclear rocket, specifically a Nuclear Thermal Rocket, heat is what we want. Assuming the reaction goes beyond the safeguards (which should be impossible), you can simply increase power to the turbopumps and flow more fuel through the reactor. This will end up providing far more thrust than originally intended (read: serious KICK IN THE PANTS), but the melt-down will not become critical.
You're quite wrong.:-) The Orion was originally intended for launches from some remote area. The nuclear pulsing could blast just about any weight into orbit, then take that same weight around the solar system. When various treaties banned the use of nuclear weapons on the ground, Orion switched to space only mode. Then they banned space-based bombs and Orion became a dead-duck.
That's why the article suggests using seven boosters together. Actually, that's not all that surprising when you think about the fact that even the Saturn V was a combination of multiple boosters.
BTW, the primary concern when we're talking nuclear rockets is the initial velocity on takeoff. Apparently, it takes a tremendous amount of energy to get the thing off the pad. Once in the air, you simply need enough thrust to slowly build Delta-V. If this did become a problem, a few short burn, chemical-based "starter" rockets could be attached (like with the Space Shuttle).
Slashdot Mirror
I'm surprised you spend that much time with these. Alternative.nu looks like an online MTV station, and last I checked, the Winamp stations were simple video loops of stuff that people thought would be cool to put online. Has something changed?
I've heard other people talk about Internet TV, but I haven't seen any concrete examples yet. And sites like IFilm are really just collections of clips. What Internet TV stations do you watch?
Modern nuclear reactors are pretty safe. Modern reactors are actually designed so that the mere act of a melt-down would cause the reaction to stop in much the same way a fuse cuts power in a surge. If something went wrong with the reactor or the pump, the engine should be designed to simply shut down.IIRC, the original author even pointed out that a failure of one engine would still allow the others to power the craft into orbit.
So safety wise, I can't really come up with a better design. Nuclear engines has enough power at their disposal to bring a craft up to orbital speed much more gently than an atmospheric technology like Ramjets and Scramjets. A structural failure of any sort could be disastrous in a scramjet. Not to mention the high possibility of loss of control.
It's interesting to read accounts from SR-71 pilots. They said that taking the thing hypersonic was a difficult feat as the craft wanted to buck at the pressures being applied. As a result, they had to fly within an exceedingly constrained flight envelope. If they failed to maintain that flight envelope, the craft could do anything from completely lose control, to twist itself into an unflyable shape. Titanium is strong, but the pressures applied at Mach 6+ are much stronger.
In any case, this is all moot. Whatever transportation technology gets chosen will be refined through use until it is as safe as a modern airline. Heck, did you know that the first jet planes for commuters had to be shut down because they were falling out of the sky? It turned out that the square windows on the planes were putting stress on the airframe. After enough flights, the airframe would rupture and the whole plane would go down. They fixed the problem by switching the the curved windows that you see in airplanes today.
You know, friendly fire isn't friendly at all. I appreciate people correcting me because it improves my education on the matter. And education is what this entire story is about. I wouldn't have posted it otherwise.
Don't think for a minute that I didn't realize that this story would bring just about every environmental wacko and uninformed person to the surface. But I was hoping that by exposing them to positive thinking about nuclear power I could get at least a few people to open their eyes and say "Look what nuclear power can do for us!"
The time has certainly never been better. About 60% of people are in favor of nuclear power and about 80% are in favor of renewing the licenses for existing nuclear plants. And despite that truth, I get attacked by EDUCATED people when suggesting that nuclear power could change everything. And I mean everything from your cell phone, to your laptop, all the way up to space exploration. We just have to stop being afraid of it.
Am I crazy? Perhaps. But I never liked to bullshit around. I will bash my way through every anti-nuclear roadblock in existence if it means bringing the benefits of nuclear power to the world.
The only reactor I'm aware of having a melt down is Chernobyl and that was a fucking *huge* issue.
Was it? About 40 people were killed, and the other three stacks continued to operate for a decade or two afterwards. It's really not much worse than any other industrial accident.
As for why it was a big deal, well that's a different story. For one, the public was still freaked about the cold war. Nukes were a thing to fear and would wipe out the entire world. Secondly, the people running the plant caused the problem by trying to use unqualified workers to do a safety test in the middle of the night. The Russian government covered this little fact over. Thirdly, the Russian government didn't do much cleanup beyond sealing the blown reactor. As a result, quite a bit of radioactive material polluted the nearby area and caused a few health problem. (Not all that different from a major chemical spill.)
You realize that you're about the TENTH person to tell me this? If you'd taken the time to read other posts you would have seen my response where I said I was using "critical" in the colloquial sense of the term. Yes, it's not correct and I'll be sure to use "prompt critical" in the future.
Now would you like to argue that a "prompt critical" situation generally results in something much worse than a large boiler explosion? And would you like to explain how I was trying to "scaremonger"? I mean, I was only trying to demonstrate how safe nuclear reactors actually are. Or did you simply read "critical", think "this guy knows zero, therefore he's an environmentalist wacko! Get him!" Do you really think that will help improve public perception?
BTW, to everyone who responded. Thank you for your corrections. I'm still pretty new to nuclear science, so my explanations may be slightly off at times. I'm glad to know that there are some of you still out there who can be polite when correcting me.
Don't you think it's a little presumptuous to say that I don't know what I'm talking about when you yourself admit to not understanding half the spectrum I'm referring to?
Besides, I said before that eCos probably has a market. It just isn't a big one (i.e. niche).
*sigh* First off, I'm not a nuclear physicist, so you have to cut me some slack. Second, I was referring to "critical" in the colloquial sense of the term. i.e. The melt-down reaches a point where an explosion happens. Not being a nuclear physicist, it's a bit difficult to know about things like "prompt critical".
Actually, I take that back. It probably came up in my private studies, but it's one of those things that tends to slip your mind when you have 20+ years of television crammed into your head. "You should run before the reactor reaches critical! Where can I run? There's no way to escape the blast!" Blech. I should have watched less TV growing up.
To compress and distribute multiple files?! Right. You just keep telling yourself that.
I'm actually speaking as an ISV who's done a lot of work to try to add as much support for RedHat as possible. Obviously I want to deliver the best experience to my customers possible, but that's not really possible when installing icons in the foot menu causes them all to disappear! And you know who that hurts? Both of us. RedHat will catch some blame for being a crappy OS, and I will catch some blame for not providing a good user experience.
mod down this fuckin karma whore.
Well pardon me for posting the story in the first place. I didn't realize how little the Nuclear Space servers could take and scrambled to post mirror links in a hurry. And I at +2 so the mirror would get seen. I'm hardly looking for Karma. I'm already capped and in no danger of dropping.
Hello, Melt Down. its a "Gaseous Core Reactor"
:-)
it can't melt its already gas.
Good point. My bad. I wasn't thinking straight.
It is when they use a not-yet-released-for-public-consumption-because-it 's-still-under-development kernel. Would it have killed them to use the stable kernel?
And it is their responsibility as an OS manufacturer to make sure the hardware works. The fact that they gave no consideration to that was a bit upsetting.
Allow me to rephrase. NERVA got up to 75,000 pounds of thrust out of the TEST rockets. The GCNR rockets are far more efficient, plus we can boost efficiency by use of particle accelerators on the plasma. Thus we can get MORE THRUST with THE SAME REACTION MASS that is used for chemical thrusters.
Think of the nuclear rockets as ultra-powered chemical rockets. Somehow we've managed to get the hydrogen to higher velocities than was previously possible with a simple chemical reaction.
BTW, Force = Mass * Velocity2. So more velocity at the expense of mass will improve our thrust. Obviously there's an upper limit to how much velocity we can obtain, so we need to throw more mass. But if you consider that a nuclear engine can throw the same amount of mass as a chemical engine (minus some "light" electrons lost in plasma conversion), then we have greater overall force coming from our nuclear than our chemical reaction. Although, to be exact we're both throwing and pulling against the plasma. First we create the plasma which is exhausted (throwing). Then we use EM accelerators to pull on the plasma on the way out. The "pull" transfers that much more energy from the mass to the craft.
That being said, I am NOT a rocket scientist, so I can't give you exact numbers. However, the article I linked to in the story does give quite a few numbers, and a bit of googling will produce even more exact numbers. (I've seen some right down to the force per molar mass on usenet. Since I wasn't going to be building one of these things myself, my eyes kind of glazed over at that.)
It has been theorized that if this happens, the molten core will burn through the earth until it reaches water
Umm... are those the same guys who thought a tether would be a good way to test the Pluto Project? (A mach 3 unmanned missile.) If the core melts, it's going to start merging with other materials. Those other materials will begin to shield against the neutrons, thus preventing the reaction.
Trust me, there's plenty of "hot" (both radioactive and temperature wise) stuff at the core of the earth.
Upon contact with the core the water will turn into steam and create what is in effect a steam cannon, blasing the core back up the hole and showering bits of the core for miles around.
Assuming you're correct (which really assumes an amount of runaway material that wouldn't be available), rockets are launched over the Atlantic for just this reason. Any unpredictable event will have as good as unlimited space for whatever destructive forces it expends. "Miles" may seem like a long distance, but in this situation we've got plenty of them.
Now, if say a nuclear disaster happens, say only a mere 5000 ft. in the air, how far will the nuclear fallout go in a worst case scenerio?!
I don't have actual numbers, but not far at all. An explosion of a nuclear rocket would produce about the same results as a chemical explosion. i.e. The remaining rocket and debris would drop to the ocean. As for a melt-down, it's like I said before. A melt-down would produce more thrust instead of an actual explosion. BTW, plutonium and uranium are pretty tough materials. An explosion really wouldn't be sufficient to turn them to powder. An uncontrolled reentry would be more of a concern. But that's where building it in a "black-box" type of shell would help mitigate the problems.
The boosters have more than enough thrust to weight ratio. (ISP of 3000-5000) The problem as I've heard it, is that a much larger thrust to weight ratio is necessary to initially get off the ground. Chemical rockets apparently overburn for the first few seconds to deliver a few million pounds of thrust that get the liftoff started. I haven't managed to verify any of this yet, but that's my understanding.
If going "critical" means that it has gone beyond the safeguards and is melting the containment safeguards (which is what I meant..) then who's to say the pumps (or any other piece of equipment) wouldn't just melt?
Because the Turbopumps are in a different part of the craft. Did you read the article? Turbopumps push a steady stream of fuel from the tanks to the core where the core heats the material to PLASMA. Don't suppose you know how hot plasma is, do you? I'll try to explain it this way: The reactor is DESIGNED to run under what would be considered melt-down conditions in a normal reactor. More heat from the reactor means more energy transfered to the fuel, which means more thrust. If you cut the thrust, the backend of your rocket will melt and fall into the ocean. The ocean will provide a new moderator that will stop the reaction completely. The reactor will still be contained in its shielding, so little to no radiation will be exposed to the underwater environment. (Not that underwater volcanos don't already put out enough of that.)
But that's all besides the point, the point was, if it DID go critical, and it DID explode, that would be inherently WORSE then if the shuttle just blew up.. You said:
"Thus the containment itself can produce a big explosion"
Doesn't that one statement agree with what I'm saying?!
No. Because you took two different designs and equated them. Nuclear engine != Nuclear powerplant. A powerplant exists under pressure. It can only operate within certain heat tollerances before a boiler explosion (and it IS a boiler explosion) happens.
A nuclear engine exists in a state where ALL the heat is being transferred to fuel. More heat is actually a GOOD thing in the engine as it provides more thrust. The problem with a runaway reaction (which doesn't just happen by itself, sorry to say) is control. You're now sending your astronauts on a trip to the moon when all they wanted was to achieve orbit. That's a problem. In many ways that's less of a problem than a failed chemical booster which would simply explode, or fail, or just about anything else. Assuming the craft survived the initial failure (not likely), a chemical booster helpfully drops you back to Earth at terminal velocity, on an unknown vector.
With a little education, you should be MORE scared of chemical rockets than nuclear ones.
It has nothing to do with the tonnes of nuclear waste produced for which the only solution seems to be "put it down a large hole, that'll do" then?
Nuclear waste is a big lie. Here's how it breaks down: we have reactors that can reprocess nuclear waste into useful fuel for reactors (e.g. the "breeder" reactor). However, doing this would require that more companies get involved with dealing with nuclear materials. Despite the fact that 99% of the "nuclear waste" is unsuitable for radioactive weapons of any kind (including "dirty bombs"), the US government has decided that it's safer to bury the stuff and cover it with cement. They apparently think that will somehow stop terrorists from developing a nuclear bomb. Go figure.
I thought you'd like that. :-)
And would dispersal be greater if the nuclear reactor went critical?! Thought so...
Here's where education is important. Do you understand what "going critical" is? Very specifically, it's a build up of heat from a "melt-down". (A "melt-down" being when a nuclear reaction gets out of control and produces excessive amounts of heat.) Usually reactors are highly contained units. All that extra heat builds up pressure that has to go somewhere. Thus the containment itself can produce a big explosion. Still, it's more like an industrial boiler exploding than a nuclear bomb. The only radiation is from any radioactive material that gets ejected. (Usually not much, and cleanup isn't too large of an issue.)
Now in a nuclear rocket, specifically a Nuclear Thermal Rocket, heat is what we want. Assuming the reaction goes beyond the safeguards (which should be impossible), you can simply increase power to the turbopumps and flow more fuel through the reactor. This will end up providing far more thrust than originally intended (read: serious KICK IN THE PANTS), but the melt-down will not become critical.
3000-5000 ISP. Per booster. How's that sound?
You're quite wrong. :-) The Orion was originally intended for launches from some remote area. The nuclear pulsing could blast just about any weight into orbit, then take that same weight around the solar system. When various treaties banned the use of nuclear weapons on the ground, Orion switched to space only mode. Then they banned space-based bombs and Orion became a dead-duck.
That's why the article suggests using seven boosters together. Actually, that's not all that surprising when you think about the fact that even the Saturn V was a combination of multiple boosters.
BTW, the primary concern when we're talking nuclear rockets is the initial velocity on takeoff. Apparently, it takes a tremendous amount of energy to get the thing off the pad. Once in the air, you simply need enough thrust to slowly build Delta-V. If this did become a problem, a few short burn, chemical-based "starter" rockets could be attached (like with the Space Shuttle).
Ah, but that's the point of stories like this. Trying to explain to the public that *managed* dangers can bring tremendous benefits.