Marcatlas
SOC-12
At these TLs the suit would warn the user...
Cargo Capacity and volume and mass
- Thread starter Badenov
- Start date
Most “radioactives” are fairly benign unless they have been in a neutron field.
Weapons grade Plutonium and Uranium are safe to handle unless / until either they are subjected to a neutron field or you manage to pile up enough in one spot to start to create a neutron field. It is worth noting that the second method is hard to do. Sustaining a chain reaction requires neutrons to be at the right speed in the same space as the target fuels.
A simple method used to store refined materials was to form it into hollow cylinders and put it into stainless steel cans. The hollow cylinders ensured that one could not stack enough material to get to the necessary concentrations. The stainless steel cans kept other materials (like water) from filling those voids. If the engineers on Earth today can design this, one could imagine this to be a shipping standard in a star faring civilization.
Now lets look at the farm boys stealing fuel rods scenario…. Either the fuel rods are not yet used or the farm boys die. XKCD describes this well.
The radiation coming off a spent fuel rod will take care of theft scenarios.
If we want to play with other radioactives, we can imagine things like Depleted Uranium. Sounds bad, right? Again, unless subjected to a neutron flux, that stuff is inert. Lead is more toxic.
We can certainly wander around the list of radioactive elements to find something that meets the plot reasons. https://en.m.wikipedia.org/wiki/List_of_radioactive_nuclides_by_half-life
Personally, I like to head off to the “Island of Stability” and summon elements that we Earthlings have not discovered yet.
Island of stability - Wikipedia
Hard for the nuclear physicist at the game table to tell you your radioactives are all wrong when you are using stuff that is still beyond the known space of our tech level.
I was under the impression plutonium was flat out toxic, for a long time.
Thank you for the explaination.Most “radioactives” are fairly benign unless they have been in a neutron field.
Weapons grade Plutonium and Uranium are safe to handle unless / until either they are subjected to a neutron field or you manage to pile up enough in one spot to start to create a neutron field. It is worth noting that the second method is hard to do. Sustaining a chain reaction requires neutrons to be at the right speed in the same space as the target fuels.
A simple method used to store refined materials was to form it into hollow cylinders and put it into stainless steel cans. The hollow cylinders ensured that one could not stack enough material to get to the necessary concentrations. The stainless steel cans kept other materials (like water) from filling those voids. If the engineers on Earth today can design this, one could imagine this to be a shipping standard in a star faring civilization.
Now lets look at the farm boys stealing fuel rods scenario…. Either the fuel rods are not yet used or the farm boys die. XKCD describes this well.
The radiation coming off a spent fuel rod will take care of theft scenarios.
If we want to play with other radioactives, we can imagine things like Depleted Uranium. Sounds bad, right? Again, unless subjected to a neutron flux, that stuff is inert. Lead is more toxic.
We can certainly wander around the list of radioactive elements to find something that meets the plot reasons. https://en.m.wikipedia.org/wiki/List_of_radioactive_nuclides_by_half-life
Personally, I like to head off to the “Island of Stability” and summon elements that we Earthlings have not discovered yet.
Island of stability - Wikipedia
en.m.wikipedia.org
Hard for the nuclear physicist at the game table to tell you your radioactives are all wrong when you are using stuff that is still beyond the known space of our tech level.
What would happen in an asteroid mining operation that was casting 30kg bars of natural uranium and stacking them on pallets in vaccuum cause that is safe to do, and then the farm boys grab the 27 pallets, load them into the cargo hold in the previous 3x3x3 stack then pressurize the cargo hold with normal atmosphere with say relative humidity at perhaps 60% at 18 degrees C. Let's further assume the local star is a proto star still forming from a cloud of supernova ejecta, and the local U is already way beyond weapons grade enrichment (well not enrichment, let's just say it has not had the 8 billion years of half life reducing the isotope that is so radioactive). Obviously the danger can be lessened or increased by the assumptions one cares to put into the scenario. Real question: Does atmospheric water act as a moderator?
Such as the assumption that the miners are not ignorant idiots and take whatever proper precautions are necessary.
Timerover51
SOC-14 5K
Weapons grade enrichment is 93%. A 30 kilogram bar is border-line critical mass depending on its configuration. Stacking a load of bars on a pallet and then stacking the pallets puts you into a likelihood of a meltdown if there is a neutron flux. You would not need atmospheric water as a moderator. The men at Los Alamos when determining critical mass for the U-235 gun device used in the Little Boy bomb did what they called "tickling the tiger". The made a hollow cylinder of highly enriched U-235 and then dropped a can of highly enriched U-235 that was small enough to cleanly drop through the hollow cylinder. The natural neutron flux was sufficient to start a chain reaction as the smaller cylinder dropped through the hollow cylinder.
I have read the story about the guy that was tickling the tiger using two hemispheres of fissile material, and the screwdriver slipped, and the chain reaction started, the guy shoved the hemi spheres apart with his hands, saving the other men in the room from dying, but he himself died.
Timerover51
SOC-14 5K
He was working with Plutonium, which has a lot lower critical mass than U-235.
Timerover51
SOC-14 5K
It happened after the Manhattan Project, later in the 1940s, following the war.
mike wightman
SOC-14 10K
Here are a couple of videos about it:
The point of the moderator is to slow down the fast neutrons so they are more easily absorbed in the nucleus of the target atoms.
Water is popular for this because it helps remove / transport the generated heat to a device that can use it (Steam Generation > Steam Plant). It also has lots of Hydrogen which has a single proton in the nucleus. This means a high speed neutron hitting the proton will impart about half of its kinetic energy to the proton before moving on to the next collision. The proton is still locked up with it’s electron to the larger H2O molecule so it stay put and releases that extra energy as heat, etc.
In your “farm boys grabbed the fuel”, I suggest it would be fun to watch them store it in the smuggling compartment, hidden inside the fuel tanks. Now to get to that secret smuggling spot the tank is empty. Once the cargo is loaded, the smuggling void is sealed and the tank is filled. Makes it hard for inspectors to get to it. Very secure.
Farm boys swing by the local gas giant / filling station, load up on fuel to top off that tank and all is well, right? Then things start to get hot. Because, you know, our handwavium starships use Hydrogen for fuel. How much pressure is there in that fuel tank? Is the Hydrogen liquid?
Did they scoop unrefined and now that it is being refined, the clean liquid hydrogen is filling the tank around the smuggling void?
Oh, the fun we can have.
Even having all this happen off the stage and the Players just encounter a disabled 200T freighter will damage from an internally vented fuel tank and a missing / dying crew. Rescue / Salvage is started but that tank will need to be patched in order to have enough fuel for a jump. Do they figure out filling that tank will be a bad idea? Even more troublesome is the theft has been discovered, reported and the local security forces are looking for the ship.
Confuse the plot more. What else was being smuggled / transported? Drugs? Slaves? Weapons? People with ownership interests will be looking for stuff. Slaves will be looking for freedom and the players may not be clear about providing that. Weapons of sufficiently high TL and government provenance can really get things interesting. And don’t forget that the mysterious hot spot in the fuel tank may not be discovered for a while. When / if it is finally discovered, the rad level in the smuggling void is off the charts, the material is no longer really desired by any reputable dealer and the folks who are interested are more on the “lets build a dirty bomb and kill the infidels” scale of sanity. Can they be trusted to actually pay and is the connection deniable enough to allow the players to clear the area before they have to answer uncomfortable questions?
This whole sequence might be a fun way to get a game started. PCs are in a run down shuttle, moving from one Belter base to another. Between jobs and the shuttle pilot gets himself killed attempting to collect an extra fee from one of the female passengers. While they are cleaning up the blood, they hear the “open microphone” transmission from the damaged drifting freighter. <for fun, swap the genders of the pilot and the victim>
Anyway, I need to get back to my campaign. Good luck.
Badenov
SOC-12
So, the conversation has gotten way off track and down the rabbit hole, though it amuses me that we have so many members that are knowledgeable enough to contribute to what is generally a very obscure branch of science, and I will dig the rabbit hole a bit deeper before I point out that this was not the main point of the thread, which was my confusion over tons generally referring to volume rather than mass.
The idea that packing a hold entirely with 'radioactives' as a cargo sounds like a bad plan even at 1,000,000 cr/ton, but that never addresses how much of each ton of cargo is actual active material. A 'ton' of radioactive cargo might be 1 m^3 of radioactive material and 13 m^3 of shielding, such that the adjacent pallet never knows that it's got dangerous cargo closeby. A 'ton' of radioactives can always refer to 'a ton as safely stored'.
Also keep in mind, Traveller (the main setting) is like 300 years into TL15, and the incidents mentioned above were the leading edge of TL6 (and TL5 was like 20 years old at the time), so the amount of understanding gained and ingrained as 'everyman' type knowlegde by Traveller's present day should be considerable. Compare this to our TL7 understanding of TL1 processes. We apparently still have actual blacksmiths, but they have so much more understanding of their processes than their TL1 counterparts, and I would say that the same thing should apply to TL15 workers handling things we've known about since TL5/6, so I can't imagine that anyone would be foolish enough to shovel in unshielded radioactives until a catastrophe happens. Forget how specialized the knowledge is today, this is ~3,500-year-old knowledge in an 1105-era campaign. That's several times as old as blacksmithing in AD2024.
Radioactive cargo may make your cargohold wildly dangerous if it gets hit in combat, but a hit strong enough to damage the shielding of your cargo might reasonably be expected to disperse enough of the contents to space in the same hit that it wouldn't go critical. And I'm not sure how dangerous it is compared to your 10-60% of hull volume devoted to liquid hydrogen fuel, which ought to be quite a problem if struck by weapons that might superheat and ignite it (given lasers are common weapons), but there's no provision for striking a fuel tank and detonating a ship, or even causing a Hindenburg-style incident. Worst case is loss of fuel (at least in the edition I own).
It might be interesting for ships to be required to use non-flammable metal hydride and drop tanks for 'safety purposes' and any old ships using liquid hydrogen storage viewed much like the Hindenburg is today.
The idea that packing a hold entirely with 'radioactives' as a cargo sounds like a bad plan even at 1,000,000 cr/ton, but that never addresses how much of each ton of cargo is actual active material. A 'ton' of radioactive cargo might be 1 m^3 of radioactive material and 13 m^3 of shielding, such that the adjacent pallet never knows that it's got dangerous cargo closeby. A 'ton' of radioactives can always refer to 'a ton as safely stored'.
Also keep in mind, Traveller (the main setting) is like 300 years into TL15, and the incidents mentioned above were the leading edge of TL6 (and TL5 was like 20 years old at the time), so the amount of understanding gained and ingrained as 'everyman' type knowlegde by Traveller's present day should be considerable. Compare this to our TL7 understanding of TL1 processes. We apparently still have actual blacksmiths, but they have so much more understanding of their processes than their TL1 counterparts, and I would say that the same thing should apply to TL15 workers handling things we've known about since TL5/6, so I can't imagine that anyone would be foolish enough to shovel in unshielded radioactives until a catastrophe happens. Forget how specialized the knowledge is today, this is ~3,500-year-old knowledge in an 1105-era campaign. That's several times as old as blacksmithing in AD2024.
Radioactive cargo may make your cargohold wildly dangerous if it gets hit in combat, but a hit strong enough to damage the shielding of your cargo might reasonably be expected to disperse enough of the contents to space in the same hit that it wouldn't go critical. And I'm not sure how dangerous it is compared to your 10-60% of hull volume devoted to liquid hydrogen fuel, which ought to be quite a problem if struck by weapons that might superheat and ignite it (given lasers are common weapons), but there's no provision for striking a fuel tank and detonating a ship, or even causing a Hindenburg-style incident. Worst case is loss of fuel (at least in the edition I own).
It might be interesting for ships to be required to use non-flammable metal hydride and drop tanks for 'safety purposes' and any old ships using liquid hydrogen storage viewed much like the Hindenburg is today.
As long as the H2 is not able to react with something (like O2), it is not a Hindenburg waiting to happen.
Actually, with enough H2, the risk of explosion (and fire) actually go away.
Yes. Another bit of obscure facts from a rather different career. ;-)
As for the CONEX box puzzle you initially proposed, I did this for other reasons while making a trip to the Middle East.
These numbers were handy:
Weight of a shipping container | Tare, max cargo | Alconet Containers
The weight of a 20FT shipping container is 2.180 kg (tare), a 40FT container weighs 3.620 kg (tare). Read more about the weight of shipping containes.
www.alconet-containers.com
| 20ft | 40ft | 40ft hc | |
|---|---|---|---|
| Maximum cargo | 28.300 kg | 26.860 kg | 26.660 kg |
| Maximum weight | 30.480 kg | 30.480 kg | 30.480 kg |
| Tare | 2.180 kg | 3.620 kg | 3.820 kg |
From this, you can get a maximum density measurement for the various containers.
IMTU, there are equivalent limits for containered and palleted loads. This keeps the cargo mass inside some standard limits that allow RAW volume limits to be sensible.
At the end of the day, we are playing a game and the value of the game system is to provide enough foundation to feel realistic _from the viewpoint of the player_. Those tables for random starship encounters, while interesting, are not a proper survey of all shipping traffic. That set of results from the available cargo list is not an accurate portrayal of the goods moving between star systems or a lot of folks are really hungry. Finally, in a game where the primary motivation of the PCs is to gain money to keep flying and/or upgrade their stuff, the monetary system is just broken. The Imperial Credit sees no inflation or deflation yet is a fiat currency, supported by an Imperial government that does not actually tax the trade that it spends all of it's money protecting. That does not work in so many ways it is just down right funny.
IMTU, that last bit, taxes, is subsumed into the costs paid by merchants to move goods in/out of the various starports and get the Imperial tax stamp for travel between the stars. Which makes goods from an E starport an interesting proposition.
Badenov
SOC-12
I'll file this under "Today I learned ..." and retract my concern about hydrogen fuel exploding. As long as the ship evacuates atmosphere for combat, of course. That procedure becomes much more urgent now, I think.
IMTU, we use 30-ton containers, about the size described above, as 'standard shipping containers'. This makes the Modular Cutter actually a lot more useful and provides a much better reason for its presence in large numbers near a starport. Sure it can do chores with specially built modules, but when its not otherwise busy, it can ferry cargo.As for the CONEX box puzzle you initially proposed, I did this for other reasons while making a trip to the Middle East.
These numbers were handy:
Weight of a shipping container | Tare, max cargo | Alconet Containers
The weight of a 20FT shipping container is 2.180 kg (tare), a 40FT container weighs 3.620 kg (tare). Read more about the weight of shipping containes.
20ft 40ft 40ft hc Maximum cargo 28.300 kg 26.860 kg 26.660 kg Maximum weight 30.480 kg 30.480 kg 30.480 kg Tare 2.180 kg 3.620 kg 3.820 kg
From this, you can get a maximum density measurement for the various containers.
Concur with all the above, but I am autistic enough to find generally my ideas of 'realistic' and other people's ideas do not always line up, so I was looking for guidance. Official, if possible. I would totally love a more reasonable trade system, the RAW (at least in Mongoose 2008) make is almost impossible to make your payments via trade alone. I realize that's not the point of the game, but I feel the games needs for it to be possible in order for the other parts to fit correctly.
AnotherDilbert
SOC-14 1K
Official? That's easy: Cargo is assumed to be 1 tonne per m³.
CT Striker, B3, p10:
MT RM, p85:
TNE FF&S, p14:
T4 FF&S, p17:
As a Dt is generally 14 m³, one Dt is about up to 14 m³ and 14 tonnes of cargo.
Badenov
SOC-12
That works, and gives roughly neutral buoyancy. It is way past overloaded for most wheeled and tracked ground vehicles in Mongoose Supplement 6 Military Vehicles, which cannot drive on normal roads past around 450kg/m^3, depending on the exact configuration.
1 tonne per m^3 will result in substantial empty space when carrying heavier things like mined ore, but will allow lighter things like manufactured goods to be stuffed in as tightly as can be managed. That is good information, thank you.
I was pointing out that T4 FF&S can have the players track the actual masses when it will be significant to the plot, the radioactives was just something dense, could have been osimum, did not matter about the point. When in space, and accellerating using reaction thrusters, (non-grav) the rules say to use the loaded mass. In most cases 1mt/m3 is fine. But when all you are doing is taking metal ores from an asteroidal mining site to an orbital refinery, with no need to land on a planet, why not fill every m3 you got with that 15mt/m3 metal ore instead of only 1/15 th. of your m3?
But, cargo in ground vehicles (FF&S p.20) and lift vehicles (FF&S p.26) is assumed to be 0.25 tonnes per m³. Not confusing or inconsistent at all.
MgT1's Vehicles assumes 0.1 tonne per m³, which seems a very low density.
