Some questions about setting up a HTGR from Reactorcraft

[Starfang42]

Playing Direwolf20 for MC1.7, with Rotarycraft, Electricraft, and Reactorcraft added. Been looking to upgrade my power system (Currently running 21 Magmatic Dynamos), so I started playing around with the HTGR in creative to get a feel for it. Thing is, I'm only getting about 4-5k rf/t average off of a system with 8 pebble bed cores (4 cores around a CO2 exchanger, 2 high, with a layer of concrete around the thing, as well as concrete around the heat exchanger/boilers), and I've made sure I'm not exceeding the 8192 torque/speed limit on the rotational dynamo, so I want to make sure I haven't missed anything with the reactor setup itself. I've gone through a couple tutorials, which were nice for the basics, but I feel like some of the details have changed (Unless I seriously messed up, 4 pebble beds are not going to max out a turbine anymore). So...Onto the questions.

1) Is whether a block can insulate or not an all-or-nothing thing, or are some blocks better than others? If there's a range, what would you recommend?

2) Should I insulate more than one layer out from the "core" of the system? One of the changelogs mentioned insulation being "less effective" for HTGRs, though that change was towards the end of the 1.6.4 line. On that note, do vanilla minecraft hoppers count as insulation? How about AE2's ME Interfaces? Haven't quite decided how I want to automate things, yet. Probably with an interface, now that I think about it.

3) How many Pebble Bed reactors would I need to max out a turbine at this point, assuming I'm using water for the steam boilers? What's the expected max torque and speed?

4) Am I correct in assuming the heat exchanger/steam boiler(s) needs insulation as well? I'm pretty much assuming anything involved in heat transfer should not be exposed to air.

Edit: Thought of another question. How much does ambient temperature affect the output of this thing? My test build has an ambient temperature of 30, for reference. Would I be better building this thing deep underground or in the nether?

 

[ax1m]

First off, a Rotational dynamo isn't anywhere near enough to efficiently convert the power from a reactor turbine. A max size turbine (i.e. 5 turbine blocks in line) at full capacity will generate about 170'000 RF/t. Anything less than a 5 block turbine will still use the exact same amount of steam, but produce way less power, so definitely go max size. You absolutely need to use the turbine generator multiblock to convert that energy, unless you feel like using several shaft junctions in split mode and about 12 rot. dynamos.
Of course none of the usual RF cables are able transfer that amount of energy, which is why you'll either wanna a) stick a Tesseract right at the output, or b) use the RF transfer cable from Electricraft, if you can afford to. Edit: An Extra Utilities hyper energy transfer node with some amount of speed upgrades would also work

As for your questions:

1) Yes insulation is an all or nothing type deal. If there is an air block adjacent the block is not considered insulated by Reactorcraft. If there is literally anything else there, it is. I usually like to go with things like microblock corners, since it still allows easy access to the core.

2) More than a single layer of insulation is not necessary, a least not for HTG reactors. This comes in later with fission reactors, which emit neutrons. You do not want these neutrons escaping, which is why you should build thick shielding out of concrete and/or steel. HTGRs do not emit neutrons, the only concern is heat loss. As explained above, anything other than air will do.

3) My default setup is 4 reactor cores around 1 carbon dioxide heat exchanger, feeding 1 heat exchanger with 7 boilers sorrounding it. This will produce just a bit more than enough steam to run one turbine at full capacity. Over time, steam will build up in the steam lines, but that doesn't need to bother you, their capacity is virtually infinite and they do not explode or anything like that. A turbine at full capacity should spin at 65 krad/s and produce 15 kNm of torque.

4) Yes that assumption is entirely correct. The core and the boiler need to be isolated, however the pipes containing hot CO2 and steam don't.

5) I'm not entirely sure on this one, but I think you'll generally want colder ambient temperatures, not hotter. Building deep underground and especially in the nether will get you closer to the reactors failure point, but not give any better efficiency. 30°C is perfectly fine though for most applications.

 

[Starfang42]

Ok, upping the number of steam boilers to 7 seems to have helped a bit, but...Are you playing the latest version? V3D? I'm pretty sure that 4 pebble beds isn't enough to max a turbine anymore. I'm not getting a constant stream of steam even with 8. Considering going back to V3C for a comparison.

 

[ax1m]

Can you maybe post some screenshots of your setup? I haven't been running an HTGR since at least a few versions back, but I looked over the changelogs and couldn't find anything about this. I'll try to do a test setup, but that'll have to wait until tomorrow, it's sleepy-time around these parts

 

[ax1m]

Alrighty, apparently I was really tired yesterday because I overlooked something in the changelogs, right in the latest update:

• ReactorCraft: Nerfed HTGR heat generation by 50%

So I started up a creative world to do some testing, and because of this change I doubled my usual core right off the bat, i.e. 8 pebble beds and 2 carbon dioxide heat exchangers, in a double layer + sign configuration. Since previously half that was easily enough to run a turbine, I expected this to work as I was used to.
However it is still not enough. In fact, nowhere near enough. Once it was fully heated up I let this thing sit to produce steam for 10 minutes with the steam grate disabled, then started the turbine, and it took just under 3 minutes until it ran out and started sputtering. From that I can extrapolate that you'd probably need something in the vicinity of 32 pebble bed reactor cores to run a turbine... which just doesn't sound right.

I highly suspect this version of reactorcraft is bugged somehow. Maybe Reika accidentally nerfed it way too much, or something else beyond my understanding is going on. I'll try summoning @Reika here, maybe he can help us out with this.

 

[Reika]

Alrighty, apparently I was really tired yesterday because I overlooked something in the changelogs, right in the latest update:


So I started up a creative world to do some testing, and because of this change I doubled my usual core right off the bat, i.e. 8 pebble beds and 2 carbon dioxide heat exchangers, in a double layer + sign configuration. Since previously half that was easily enough to run a turbine, I expected this to work as I was used to.
However it is still not enough. In fact, nowhere near enough. Once it was fully heated up I let this thing sit to produce steam for 10 minutes with the steam grate disabled, then started the turbine, and it took just under 3 minutes until it ran out and started sputtering. From that I can extrapolate that you'd probably need something in the vicinity of 32 pebble bed reactor cores to run a turbine... which just doesn't sound right.

I highly suspect this version of reactorcraft is bugged somehow. Maybe Reika accidentally nerfed it way too much, or something else beyond my understanding is going on. I'll try summoning @Reika here, maybe he can help us out with this.

I have since increased the HTGR power output a bit, but HTGRs can also fail now, making them much less abusable.

If there is literally anything else there, it is.

Not true. Several blocks like buttons count as air. FMP blocks do not, purely for technical reasons.

 

[Starfang42]

What do you mean by fail exactly? Will they explode like the other reactors now? And I tike it this is going to be an upcoming update?

 

[Reika]

What do you mean by fail exactly? Will they explode like the other reactors now? And I tike it this is going to be an upcoming update?

No, they melt. Yes, this is in v4.

 

[Starfang42]

I thought they already melted into a puddle of lava if they overheated?

 

[Reika]

I thought they already melted into a puddle of lava if they overheated?

Yes, but they now do that more easily.

 

[rowlock]

Ah, I'm glad I'm not the only one experiencing this. I also set up an 8 core plus-shaped config around two CO2 exchangers last night, my first foray into Reactorcraft, and was scratching my head like crazy wondering why it was barely able to tick over the 800C threshold to produce hot gas. 22C ambient in my case, and I was getting spikes up to about 15MW with averages of about 3MW and some moments that the turbine stopped spinning entirely.

Glad to hear things are increased again a little in v4 - looking forward to seeing how that goes. It's a shame people were abusing HTGRs, The evening I spent building it out was a good introduction to Reactorcraft, and really helped work out the kinks and concepts. Would be a shame to feel like it wasn't worth it for power purposes.

Thanks for your hard work, Reika, and for the continued communication here. Rotarycraft has been one of my must-have mods for a long time, and I'm glad to be finally getting my teeth into Electricraft and Reactorcraft now too.

 

[Plasmasnake]

So I decided to hop into creative to see how the seemingly giant nerf was treating the HTGRs and all I have to say is... wow. I couldn't get a single LP turbine to spin at max capacity with 8 PBRs. In fact, it never even went past 200MW. That's insanity.

Spoiler

Now I always built these in deserts, but from what I have experienced you may be forced to place these both underground and in the desert if you want to get any sort of decent power without an insane amount of PBRs. Unfortunately, I would have to suggest that you should just completely skip HTGRs unless you are doing it for neutron absorbers. I really don't think the cost is worth the payout and you might just be better off using 1 or 2 gas turbines :/

 

[Pyure]

Now I always built these in deserts, but from what I have experienced you may be forced to place these both underground and in the desert if you want to get any sort of decent power without an insane amount of PBRs. Unfortunately, I would have to suggest that you should just completely skip HTGRs unless you are doing it for neutron absorbers. I really don't think the cost is worth the payout and you might just be better off using 1 or 2 gas turbines :/

I'm not clear on why you figure multiple gas turbines at lower MW would be superior to a 200MW pebble bed reactor. The reactor's fuel is even easier to mass produce.

The more logical deduction here might be that there's an incentive to upgrade to a proper fission reactor, which will easily max out several turbines.

 

[Reika]

So I decided to hop into creative to see how the seemingly giant nerf was treating the HTGRs and all I have to say is... wow. I couldn't get a single LP turbine to spin at max capacity with 8 PBRs. In fact, it never even went past 200MW. That's insanity.


Now I always built these in deserts, but from what I have experienced you may be forced to place these both underground and in the desert if you want to get any sort of decent power without an insane amount of PBRs. Unfortunately, I would have to suggest that you should just completely skip HTGRs unless you are doing it for neutron absorbers. I really don't think the cost is worth the payout and you might just be better off using 1 or 2 gas turbines :/

Or you could build HTGRs properly? Not every reactor has to be four cores around a heat exchanger.

 

[rowlock]

Or you could build HTGRs properly? Not every reactor has to be four cores around a heat exchanger.

OK, now that right there is an interesting quote. Intuitively surrounding the CO2 exchanger with the heat-generating blocks seemed the most obvious way to combat a low amount of generated heat versus the relatively giant cooling power of the CO2. But when it comes to physics, the gut is often a terrible guide.

Think I'm gonna waffle around a bit and see if there are any arrangements that will make better use of the heat we are generating.

 

[Plasmasnake]

I'm not clear on why you figure multiple gas turbines at lower MW would be superior to a 200MW pebble bed reactor. The reactor's fuel is even easier to mass produce.

The more logical deduction here might be that there's an incentive to upgrade to a proper fission reactor, which will easily max out several turbines.

Well here is my thought process:

You need a good lubricant supply to spin the turbine.
You need fairly low power for the heat exchanger
You need to have a friction heater to even make the TRISO pellets
You need a good water supply to avoid overheating
You also probably need a pump for the steam lines
Then there are resource requirements for all of these.

All these things require power and it isn't apparent to how much power profit is made with the HTGR. Of course, most of these requirements are also present for a generic fission reactor, but those generate a heap more power. I distinctively remember building a smaller HTGR back in v24 with my (according to Reika improper design) and it ran a turbine with no issues. I just feel like the work isn't worth the payout anymore. Maybe I just have to relearn ReC because it changes after each update. Maybe I am just dumb and there is a giant flaw in my reasoning, which is probably true. I'd like to learn by being a vocal idiot rather than just being a silent idiot who continues to be an idiot.

 

[Pyure]

I can't really debate this too much because I've never built an HTGR except in creative. I always skipped straight from a Gas Turbine to the Fission Reactor.

That said: my understanding was that the HTGR was just so simple to build and maintain that a large number of people would rather scale it up (multiple HTGRs) than upgrade to Fission (which to be fair is inheritantly dangerous due to being chunk-unload-unfriendy. Not in a fun way either; all players I know rely on world backups.)

Rather than remove the HTGR, a reasonable alternative was to make the HTGR less appealing. You can still build them, but you're incentivized to upgrade (fission) rather than simple scale up.

I traditionally shoot down a significant number of Reika's design decisions but this one I can't really argue. Take a look at the standard fission reactors, they're fun to play with if you back your world.

 

[fredfredburger]

There's also the fact that the fission reactor requires processed and centrifuged enriched uranium. The processors might be unpowered but the centrifuge will eat 268 MW all day long and still not run very quickly. Then there's the hazardous waste to deal with and the neutron radiation from it and the cores themselves.

I'll also back what Pyure said about instability. HTGRs aren't going to mess up your base like fission reactors are. If by some miracle you an HTGR to meltdown, there's no radiation and no corium produced. You'll lose some fuel pellets and the cores, but not much else.

I tested out a 2x16 core HTGR in creative which had a very slighty positive steam output with one turbine and the heat exchanger could keep up running on a geared steam engine.

 

[Plasmasnake]

I can't really debate this too much because I've never built an HTGR except in creative. I always skipped straight from a Gas Turbine to the Fission Reactor.
I traditionally shoot down a significant number of Reika's design decisions but this one I can't really argue. Take a look at the standard fission reactors, they're fun to play with if you back your world.

That's my problem right there. I see no reason to build a HTGR anymore. I'm not going to try attacking the nerf anymore, because the guy who made the mod obviously can own me any day of the week, but I just cannot shake the feeling like it's not worth the effort... like it took way too large of a hit. I hope I can get my point across because I'm having a lot of trouble finding the words to explain it.

-Edit- or perhaps its much simpler than that since in my particular mod pack, dealing with the hazards and needs of a fission reactor is much easier than it would be in other packs, especially official ones.

 

[Pyure]

Correct me if I'm wrong, but the centrifuge for enriching uranium only requires 1 torque. At 268M (?) rad/s it should be running obnoxiously fast. I used to run 3 or 4 of these each on a microturbine since it was the simplest engine to gear up the speed on.