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snowcelt
2004-Nov-16, 09:51 PM
Let us think that we could go to a earth like place, and we need a power source, and we choose fission as that source.

Let us say that the colony would have ten thousand original colonists. Let us further say that you want the fission reactor to last for fifty years. Furthermore, you want this reactor to be able to generate enough energy for the decendence of the colony. Ten thousand on landing: twenty five years later twenty thousand, fifty years later there will be forty thousand people looking for energy that you and I take for granted today.

1. How practicable would this be?
2. How much would such a system cost?
3. Could a somewhat isolated colony of this size run this beast---along with all other systems that would be neccessary?

Ilya
2004-Nov-16, 09:57 PM
Nuclear power plants capable of supporting 40,000 people are commonplace today, even if not exactly cheap. For a civilization capable of sending 10,000 people to another star, such a plant would be like a child's waterwheel to us. I suspect the ship's power consumption -- and onboard power plant, -- would dwarf it completely. Which is why a lot of SF stories involve using the colony ship as the colony's power plant.

frogesque
2004-Nov-16, 10:08 PM
Ilya wrote:


...... I suspect the ship's power consumption -- and onboard power plant, -- would dwarf it completely. Which is why a lot of SF stories involve using the colony ship as the colony's power plant.

Which makes a lot more sense than using that same ship to also send a DIY builditbynumbers kit which would take away payload from other essentials like food and water. If the planet/moon/asteroid is Earth-like then you wouldn't need food and water but you wouldn't need a nuke installation either.

snowcelt
2004-Nov-16, 10:26 PM
What if the ship's drive was not compatable with a colonies' need for energy?

Let us say that the ship got us to this place with a "warp feild'. No power except by a fission plant dragged from earth.

Glom
2004-Nov-16, 10:38 PM
Is it my birthday?


Let us think that we could go to a earth like place, and we need a power source, and we choose fission as that source.

What else would we choose? We would need something powerful yet compact and aside from fusion, not yet feasible and possibly not as compact as would be required, fission is the only option.


Let us say that the colony would have ten thousand original colonists.

Let's say per person (and of course this in an average over the population, which includes all industrial needs) 1kW of power. That means that at first, the power requirements will be 10MW. A nice little Magnox will handle that... except that Magnox is crap.


Let us further say that you want the fission reactor to last for fifty years.

I guess naval is the best way to go on that. 40% enriched uranium with burnable poisons so the reactor can go for fifty years without refuelling. Pressurised water is common in naval reactors, but more outlandish would be lead-bismuth cooling which take the form of nuclear "batteries". However, these require regional reprocessing. The batteries can have a 20 year life, so if three were carried, then the timeline is satisfied, but with the requirement for refuelling.

I think the best would be molten salt reactors, which used fuel dissolved in sodium flouride coolant. They operate at high temperature for good efficiency and is versatile in use. The fuel use is low, which is obviously good for the fledgling colony and can be made to run on thorium easily enough. They also use in built recycling. The problem is that MSRs are designed to be 1GW and I'm not sure how adaptable they would be like the LFR to smaller groups.

VHTRs are small and versatile, but they're designed for a dynamic developed economy. They are less compact for the energy, are only useful through large scale industry, and are strictly open cycle.


Furthermore, you want this reactor to be able to generate enough energy for the decendence of the colony. Ten thousand on landing: twenty five years later twenty thousand, fifty years later there will be forty thousand people looking for energy that you and I take for granted today.

First off, I have to say that eventually, we'd expect the colony to develop their own energy independence through the use of thorium and uranium reserves on the new planet.

For the moment, I am strongly looking towards the LFR. There is a 50MW version that uses a replaceable core "battery" with solid lead-bismuth coolant encasing the core. The battery is inserted into the reactor, the coolant is melted and the energy of the reaction is harnessed. If a few of these batteries were brought along, we could expect that the colonies needs could easily be met for a hundred years, even up to the forty thousands population.

After one hundred years, we'd expect the colony would have developed its own energy resources. They could also develop suitable recycling facilities so my answer would be the lead-cooled fast nuclear battery.

frogesque
2004-Nov-16, 10:40 PM
What if the ship's drive was not compatable with a colonies' need for energy?

Let us say that the ship got us to this place with a "warp feild'. No power except by a fission plant dragged from earth.

Then I would say you have designed the wrong type of system to transport a new colony. Your scenario would only be appropriate for a marooned ship and that would only have to maintain its own crew from its own life supports.

snowcelt
2004-Nov-16, 11:15 PM
What if the ship's drive was not compatable with a colonies' need for energy?

Let us say that the ship got us to this place with a "warp feild'. No power except by a fission plant dragged from earth.

Then I would say you have designed the wrong type of system to transport a new colony. Your scenario would only be appropriate for a marooned ship and that would only have to maintain its own crew from its own life supports.


I do not mean quite what you state. I mean, what if your drive has no practicable use 'ground side.'

I am not looking for a hybrid drive/energy converter.

I like what glom is talking about. All are invited to make a solution as to if we could go to a star today easy. We can carry lots of stuff. However, what we want is the lightest, fastest, and the most powerful power source for the buck.

Not trying to be a Killjoy. Is there a way that someone could go to another star with what we have for technology? Personally, I can not see this. On the other hand. If someone came up with a "warp drive" and sailed to the next stars, would it be practicable to carry a independent fission reacter?

snowcelt
2004-Nov-16, 11:18 PM
I see what you mean frogesque. Think like as if god put the colony where it will be. There is no way that god will run a powersource for the next fifty years.

Van Rijn
2004-Nov-17, 12:16 AM
You might be interested in the possible Alaska micronuke project (do a search on "Alaska nuclear reactor"). For instance:

http://www.adn.com/front/story/4214182p-4226215c.html

It would be a 10 MW reactor that would run 30 years on a small fuel cartridge.


Not trying to be a Killjoy. Is there a way that someone could go to another star with what we have for technology? Personally, I can not see this. On the other hand. If someone came up with a "warp drive" and sailed to the next stars, would it be practicable to carry a independent fission reacter?

Just maybe, with an absolute worldwide effort we could build an Orion drive generation ship to go to Alpha Centauri. It would take several centuries (at least) to get there. The "Starflight Handbook" by Mallove and Matloff provides a really good overview of possible slower than light starship technology.

As for FTL travel, it is impossible in theory. You can assume anything you want for a fictional story of course.

Sheki
2004-Nov-17, 06:06 PM
Scowcelt wrote:


Is there a way that someone could go to another star with what we have for technology?

I have been wondering about this a bit myself lately. I have been thinking along the lines of what van rijn wrote:


Orion drive generation ship to go to Alpha Centauri. It would take several centuries (at least) to get there

But I am a bit more optimistic. I figure (admittedly based on no particular expertise at all) that if we (humanity) absolutely had to do it, we should be able to travel to the nearest neighbouring star in less than a century. Of course the expense would be just obscene...

I figure it would mean a multi-trillion dollar initiative starting with about 10 - 15 years worth of directed research on orion drive technology, and related life-support technologies. The latter half of this period would be used to re-tool the ground-based infrastructure to support an orion-type launch. I figure if we can perfect the blast-plate and shockabsorption engineering we could get a ship going at a pretty good speed. I am thinking orbital insertion around the target approximately 65 years from the word go. Anyone disagree, that if we spend about a hundred billion a year on researching the needed techs for the next 10 - 15 years we couldn't build a ship that could travel to our closest neighbour in 50 years of flight time?

I also have been toying with the notion that we could send an unpiloted probe to the next star system even faster. Assuming that the probe could take about 30 Gs of accelleration without breaking, and assuming it does not have to slow down (fly-by mission).

Thoughts?

Sorry, i don't have anything to add about powering the colony.

Sheki