Vessel Transorbital tug / Hauler

[Urwumpe]

Just curious. I don't know much about this style reactor, obviously nothing like the pressurized water plants on my Enterprise. What is the heat sink for the fission products after shutdown? Of course that can be minimized if it was run near idle for a substantial time before shutdown. We ran the turbogenerators until residual product output decreased enough, then dumped steam to the main condenser. Would the coolant pumps with radiators to space be enough heat sink? Are you planning on criticality be used to heat the reactor or just use the coolant pumps. We used the coolant pumps and fluid friction to heat up the plant before pulling rods.
I think it'll be interesting to play with this one.
Never mind the shutdown part, I just realized your #106 where you said you'll ignore decay heat for now.

No, its more like a gas-core reactor, running on a mixture of Helium and Xenon (HeXe, Helium for heat capacity, Xenon for density), with a single primary loop running in the Brayton cycle, not the Rankine cycle like a PWR does. The Brayton cycle is what gas turbines use. Also, the moderator is not water in this case, but a carbide at low power operation (for producing electricity) and hydrogen gas in high power mode.

Since it is operating on gas, the compressor already puts some amount of heat into the coolant by its operation, when bypassing the radiator during startup, this should be able to quickly heat the reactor to about 600K. Its just maybe 50 kg of coolant in the system, including 16 kg in the 600 psi accumulator tank to compensate changes in volume during operation. While the reactor is slowly heating up, small amounts of liquid hydrogen are passed through a heat exchanger, turned into gas and starts filling up the other tie tubes in the reactor and adding a small amount of moderator more.

From this point on, the control drums are slowly rotated to expose more reflector surface, until reactivity has climbed high enough to let the reactor become critical. In low power mode, the reactor power should mostly depend on delayed neutrons, like in a PWR, but in NTR operation, this seems to change towards a fast reactor type of operation.

From what I can tell from how a SCRAM was supposed to work, the simplest solution to the residual heat was to pulse hydrogen through the engine (producing tiny amounts of thrust) for rejecting heat until the HeXe coolant loop was able to handle the coolant alone. An intermediate step could be using the hot hydrogen gas attitude control system for dumping hot hydrogen gas from the reactor tie tubes without producing net thrust. Because of the small size of the reactor, the ultimative way to stop the chain reaction would be explosively ejecting the control drums from the reflector, increasing neutron leakage. As long as enough drums leave the reflector (just 1 or 2 would be fatal), the reactor would stop.

I'll add decay heat later, in first place, it is now about producing a good enough model for going on with the rest of the spacecraft.

 

[Urwumpe]

We can, if you quickly explain how that works and how to set it up... I thought what I was doing was the dependency handling of visual studio.
I'm not very fond of multi-module projects if the libraries are not really part of the project, i.e. I treat them as 3rd-party dependencies, because that's the level of separation I wanted them to have. In the case of Oparse that's a bit iffy though, since most of the code is contained in the headers anyways because they're doing a lot of generics, which apparently in C++ you have to do completely in the headers.

You can take a look at the "VC++ directories" settings for the project, there should be a section for public project content. those files would automatically included in any project referencing it. To reference a project, there is a node called "References" ("Verweise" in German) in the Project Explorer (just disable the remove all files view there). Just adding it to the project dependencies for the build order in the solution is not enough. When you added it to references, VC++ will automatically add the public include directories of that project and reference the library files for it.

Its quite nice to use, slightly more comfortable than doing everything manually. Also it allows a distinction between internal and public header files.

 

[jedidia]

Also it allows a distinction between internal and public header files.

So how does VS know which include directories in a project are public and which private? Because that's what seems to have gone wrong when you referenced Oparse. Its include directory was not added to the configuration of the reference...

 

[Urwumpe]

So how does VS know which include directories in a project are public and which private? Because that's what seems to have gone wrong when you referenced Oparse. Its include directory was not added to the configuration of the reference...

Thats should be mentioned in the project settings for OParse. Also, I did not yet reference it that way, because it wasn't configured.

 

[jedidia]

Thats should be mentioned in the project settings for OParse. Also, I did not yet reference it that way, because it wasn't configured.

Sorry, you'll have to help me out here a bit... the only way I know to add include folders to a VS project is the "include folders" option in the VC++ Directories tab. OParse has the correct include directory noted in there. where else do I have to put them?
Wat I'm seeing when checking out your fork is that you added Oparse directly to your solution, and in the project configuration that is active in the solution, OParses include folder is missing.
So, this thing with referencing is different to a solution with multiple projects? What I'm still not quite clear about is why you pulled these projects into the solution in the first place. If you cloned them in the right place, the OrbitalHauler project configuration should have picked them up without issues. I really tried to make this as painless as possible...

 

[Urwumpe]

Can you wait until the evening? I have some paid work to do, before I could configure the projects as an example.

 

[jedidia]

Yeah sure, didn't mean to hurry you. In fact, it's doubtful I'll have any time at all today to work on it.

 

[Arvil]

Hmmm, looks like I've some reading to do about LANTR, Brayton cycles and such.

 

[Urwumpe]

Hmmm, looks like I've some reading to do about LANTR, Brayton cycles and such.

If you want some literature recommendations:

Innovative concept for an ultra-small nuclear thermal rocket utilizing a new moderated reactor

Although the harsh space environment imposes many severe challenges to space pioneers, space exploration is a realistic and profitable goal for long-t…

www.sciencedirect.com

https://ntrs.nasa.gov/api/citations/19950005290/downloads/19950005290.pdf

https://ntrs.nasa.gov/api/citations/20150006874/downloads/20150006874.pdf

 

[MaxBuzz]

On December, 2021, a Angara rocket with an upper stage launches with a nuclear tug model



several of MLM "Nauka"experiments are dedicated to the nuclear tug (experiment "Капля-2")
it is worth recalling that Russia is creating two nuclear tugs "Nukcleon" and "Zeus"

 

[Urwumpe]

Ok, so we have some weeks to finalize our model design and then ask them to launch a subscale model of our for ummm "testing purposes", "Engineering science"....

 

[MaxBuzz]

Yesterday Biden was so jealous of Merkel for Putin that he imposed sanctions on any activity in Russia

 

[Urwumpe]

Yesterday Biden was so jealous of Merkel for Putin that he imposed sanctions on any activity in Russia

The German perspective is a lot different there. But that is politics and not add-on development.

 

[N_Molson]

several of MLM "Nauka"experiments are dedicated to the nuclear tug (experiment "Капля-2")

Looks based on the trusted Blok-DM architecture, I'm on Tianwen right now, but I'll sure can add later a nuclear version of the tug to the Proton, as a "what if" scenario.

 

[MaxBuzz]

I am working on splitting the Soyuz ship into three parts and firing a parachute

photo of the model of the tug starting in December, 2021

 

[MaxBuzz]

diagram and image of a nuclear reactor

 

[Urwumpe]

Interesting, it also uses HeXe as coolant. So, our design starts to get pretty conservative. Any suggestions for obscure sci-fi technology to include? ?

(Just kidding. jedidia is the "customer" there, but I wanted to stay close to available technology as long as possible)

 

[Urwumpe]

Who wants to know more about the basic design work so far: This is how the planned implementation now looks like compared to the abstract basic Brayton cycle.



Most of the additional stuff is needed for supporting startup and NTR mode operation. The numbers denote how the connections will be named in the implementation.
The accumulator is needed for controlling coolant loop pressure. The NTR Heat eXchanger is used for reducing the coolant temperature by about 1000K, when the reactor is operating at 2700K. The radiator bypass is only needed during startup for quickly increasing the temperature of the coolant loop. Otherwise the compression heating wouldn't be strong enough to really heat the core before going nuclear. In an emergency situation or during startup, the motor generator keeps the coolant flowing at maximum mass flow rate.

One later option for development is to create multiple redundant coolant loops. But now I am happy if I have just one big coolant loop done.

 

[Urwumpe]

Once we have this one mostly done .... what about modifying the basic spacecraft to become an orbital construction vehicle? Replace the cargo containers with a huge platform for EVA work with attachment points for parts and tools, two strong robot arms, more flood lights...

 

[jedidia]

Well, the code is open, so whoever wants to can have a go at it. I can't really plan that far into the future right now...