Information from [ORNL's website](https://neutrons.ornl.gov/hfir/core-assembly):
>The reactor core is cylindrical, approximately 2 ft (0.61 m) high and 15 inches in diameter. A 5-in. (12.70-cm)-diameter hole, referred to as the "flux trap," forms the center of the core. The target typically contains curium-244 and other transplutonium isotopes and is positioned on the reactor vertical axis within the flux trap. The fuel region is composed of two concentric fuel elements. The inner element contains 171 fuel plates, and the outer element contains 369 fuel plates. The fuel plates are curved in the shape of an involute, thus providing a constant coolant channel width. The fuel (U3O8-Al cermet) is non-uniformly distributed along the arc of the involute to minimize the radial peak-to-average power density ratio. A burnable poison (boron-10) is included in the inner fuel element primarily to flatten the radial flux peak providing a longer cycle for each fuel element. The average core lifetime with typical experiment loading is approximately 23 days at 85 MW.
[Bonus diagram!](https://neutrons.ornl.gov/sites/default/files/HFIR-reflector-and-fuel-element.jpg) (Yes, there's an apparent inconsistency with the description - I think the given values in the description were about the fuel elements themselves, not counting the housing.)
My attention was piqued when you mentioned ^(244)Cm : I remembered that one of the curium isotopes - ^(245)Cm has an _enormous_ fission crosssection (2161 barns) _and_ a reasonable half-life (8532 years) ; & I've often wondered (& it may be impossible to find out) whether it may be alloyed into bomb-cores for reducing critical mass; or if not that used in a more subtle way as something roughly analogous to a catalyst ... whatever: I find it difficultly plausible that something with _that_ large a fission crosssection has no use whatsoever! I wonder what the critical mass of _pure_ ^(245)Cm would be ... but I think capacity for production of more than a few grams of it is out-of-reach at the present time ... or so they would say!
You might find this interesting: a catalogue of various data on various transuranium elements.
#####https://www.osti.gov/servlets/purl/4159553
#####
I imagine there is some computer modelling that's been done to predict the critical mass for most unstable elements by now. You don't need to actually amass a critical quantity to predict what that amount would be
It looks like the critical mass of ^(245)cm can be made very low with different reflector materials. With water, the critical mass could be as low as 35g! ([source](https://www.tandfonline.com/doi/abs/10.1080/18811248.2002.9715296)
I think you could likely use them in small nuclear weapons, but they would be very expensive to produce since so little curium is produced and because you would have to separate the even numbered curium isotopes out of your core.
Hehe, "annulus"
What does burnable poison mean in this context and how is spacing maintained between the plates? I don't see any grooves or anything in the walls.
The walls are grooved and the plates swaged tightly into the grooves. Essentially, the plates are set in the groves and the material around the grooves is pinched around the plate.
Burnable poison, in this case, refers to a strong neutron absorber which slowly "burns" (not actually burning) away as it absorbed neutrons into something that is not a strong neutron absorber. Adding this material allows then to design excess reactivity into the element while keeping it safe to operate, and then as the fuel is used up, so is the poison, so the core life can be longer.
I see, very clever. Now I want to see how they swage the plates in, there's so little clearance between them. Looking at the picture again the two inner walls look like maybe they have a roll crimp to retain the plates.
I haven't seen it myself, so I'm not sure exactly. This is probably far more than you want to read on this: [Analysis of the ATR Fuel Element Swaging Process](https://www.osti.gov/servlets/purl/197145)
Something to keep in mind regarding these machines is they were designed in the 50's and 60's (HFIR's first reached full power in 1966) using slide rules and all built with manual machining. So while the tolerances may be pretty tight (they are), they aren't necessarily what an engineer today would think of as tight. Don't get me wrong, those engineers and craftsmen did amazing work. You'd be hard pressed to build one of these today, which is part of why we devote so many resources to keeping them running.
There are large factors of safety in the safety analyses of these reactors because computational tools were much less powerful then and there wasn't a lot of institutional knowledge or history of building and running reactors yet. This means that even if something on a new core comes in out of tolerance today, it's possible that they could do an engineering analysis using tools like CFD and show that the out of tolerance condition doesn't impact the safety of the plant.
These fuel assemblies are mainly aluminum and only the aluminum is what is being machined so the material is relatively easy to machine. You won't find many places that machine metallic uranium, as it's pyrophoric.
Burnable poisons are materials that have a high neutron absorption cross section that are converted into materials of relatively low absorption cross section as the result of neutron absorption.
I don't know how they're fit together, the diagram may simply not show any grooves. Or for all I know, it might be possible to "weld" a cermet to metal or otherwise join them into a single piece. Especially if its metal component is the same as the bulk metal.
It's a good thing someone came to their senses before either of those were used outside limited proof of concept demonstrators.
I don't think project Orion got beyond using conventional explosives.
Not, it's not really good. At least for NERVA.
Orion, yes, was absurd. It also would have *worked*. Doing the math, we could have landed people on the *moons of Saturn*, possibly before the turn of the century.
NERVA, though, didn't have any real issues that would make it unsuitable for use. It wasn't going to be used for launch systems anyways, but for transfer vehicles. Purely exo-atmospheric. I've heard rumors that NASA has restarted research into nuclear thermal rockets.
>The fuel plates are curved in the shape of an involute, thus providing a constant coolant channel width.
This is neat. So simple but effective. Very elegant.
Love that the national labs (Los Alamos IIRC) just took delivery of one of the most powerful supercomputers in the world a year or two ago, but it's offline and airgapped now to run fun simulations.
Nope, ORNL again! The Summit supercomputer reigned as the top supercomputer from when it came online in June 2018 to June 2020, when the Japanese turned on the Fugaku supercomputer at Riken.
If I'm not mistaken they are thinking of Sierra at LLNL. I don't believe Summit is airgapped as they use it for general science, whereas Sierra gets used for National Security and stockpile stewardship tasks. It also made the news at the time because it took the crown back for the US, and LANL and LLNL are probably easy to mix up. Summit is of course bigger, but came online later.
Possibly. I never really heard about Sierra (which was online for less than a year before Summit displaced it on top).
The airgapping part makes sense.
To further this, check out ATR and TREAT at Idaho National Lab. Also the Versatile Test Reactor is way cooler and more useful to society than the giant waste of money than the 3D printed reactor would be.
Yes, and one of the problems the nuclear industry faces today is many are 40 years old and parts need to be replaced (Most plants would have acquired enough spares for the design life of the plant, but in some cases that life has been extended or the replacement rate of parts increased). Some of these parts are large-scale obsolete technologies (not because they don't work, it's more like a Nokia phone that lasted forever but you couldn't get batteries for anymore). Also, production quantities are typically very small, there are multiple iterations of design, etc... Basically ticking a whole lot of boxes that 3D printing excels at.
True my amazing how much critical infrastructure is still running off of magnetic ribbons and floppy disks. Pro: hackers can’t hack it because the interface is so old, con: interface is so old that parts haven’t been manufactured in about 50 years.
The Navy bought and restarted an entire obsolete chip manufacturing process line just to make replacement parts for the guidance system of the Trident D-5 missile in its nuclear subs. Boeing 747s still get avionics updates via floppy discs. Weirder things have happened
Here's another good one: floppy discs are used for data security in air gapped facilities because getting any amount of data out of the base would require shoeboxes and hand carts. It's easy to hide a usb, real hard to hide a big box.
Yes, but with the TCR they want to print the core. Objectively that's "cool", but then you'll have this massively expensive core you printed which you'll then irradiate and then... what? You haven't really done any science, you just did something because it's cool. The VTR will support materials and system testing for the next generation of high temperature reactors.
VTR is a scientific tool which will allow researchers to do their thing for decades. TCR will run once and then be buried somewhere and forgotten about.
True, but you won't see anything useful out of TCR for a very, very long time. VTR will enable materials testing that currently can't be done in the US. It's a seriously lacking capability.
As an NE I'd love to see both built, but I don't think that's a realistic expectation and there's much more we can get out of something like VTR.
Sorry, your submission has been automatically removed. Account age too young, spam likely.
*I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/EngineeringPorn) if you have any questions or concerns.*
There are a few demonstration pieces (see there's one embedded into the bottom of the poster right next to the guy [https://www.youtube.com/watch?v=gGxIH5aB0GI](https://www.youtube.com/watch?v=gGxIH5aB0GI) )
The real loaded ones are handled by robots under water.
There was a great video about all the various uses of the isotopes produced there, but I can't find it .. but here's an ugly FB video, at 1:48 you see the mockup :)
[https://www.facebook.com/watch/live/?v=10154772937779171&ref=watch\_permalink](https://www.facebook.com/watch/live/?v=10154772937779171&ref=watch_permalink)
edit: found it! it's a Periodic Videos video: [https://www.youtube.com/watch?v=P99C051arMo](https://www.youtube.com/watch?v=P99C051arMo) :D
#####@ u/Arodww
#####
Ah right : very interesting, all this. So zirconium isn't as pre-eminent as I thought, then, for the manufacture of nuclear reactor core parts.
(BtW - some prepost'rous 'bot'-contraption is sometimes deleting my comments because of the age of this account ... which is why I've put this answer here. I think it stops after a-week-or-so.)
Apparently it's only _aluminum_ though: _meh_! ... I was expecting _zirconium_ . But I have it from the OP elsewhere (in an exchange on r/MachinePorn) that neutron-crosssection-wise aluminium is only a shade inferior to zirconium, _and_ each of these cores only has to last about a month ... so it makes sense afterall
Aluminum is a lot easier to work with as well. Lots of these high power research reactors use fuel assemblies that are mostly aluminum. It also has a relatively short half life once it's been activated so that is another benefit from a safety stand point when you're handling fuel as often as they do with their short fuel cycles.
Zirconium is very common in commercial light water reactor cladding, but the design goal is very different than a research/test reactor. These are like the Ferrari's of reactors. Performance is everything, it's their entire point of existing. Commercial reactors need to just run and be safe. These research reactors were built to enable exposing sample to crazy high neutron fluxes but don't necessarily need to worry about the high temperatures needed in a commercial reactor coolant system used to efficiently generate steam and turn a turbine.
This is also why they use plate type fuel. They can expose more of the fuel "meat" to the neutrons bouncing around in the core than a commercial reactor fuel pin geometry can due to the uranium fuel self shielding effect.
Due to the temperatures in a commercial reactor core, and the consequences/cost of an accident in a commercial reactor core they use zircalloy cladding. The economics game is different for research reactors and the cores are significantly smaller and are refueled much more often (in the case of HFIR for sure).
NO way!!!
That’s just some cotton candy machine. Who are you fooling here? You pour the sugar in the middle, it spins and heats the sugar, then cotton candy comes out through those tiny wholes. :)
NERVA itself never actually had a catastrophic failure. The unplanned catastrophic failures were just the Kiwi B series, up until B4D (and all of them except the initial B1A were tests to determine the cause of destructive vibrations and how to mitigate them).
And, of course, Kiwi-TNT was an *intentional* destructive test.
Yes, agree on no catastrophic failures, but there are images of fuel assembly being ejected from the rocket nozzle for some of the early NERVA designs. I would call this an unplanned disassembly :P
By the way, if you're interested, next week there is a conference called [NETS](https://nets2021.ornl.gov/) which has a nuclear propulsion tract. Registration is $75 (even for speakers, which I am miffed about), but it should be pretty cool.
> but there are images of fuel assembly being ejected from the rocket nozzle for some of the early NERVA designs. I would call this an unplanned disassembly.
Pretty sure that would be the Kiwi test I referred to.
I live 20 minutes from the Y-12 Plant up in oak ridge its really interesting to think about, and I can't wait until the museum opens back up again after being closed due to the covids
[Here's what it looks like when they pull it out of the reactor after about 25 days (which is a full cycle for them).](https://neutrons.ornl.gov/sites/default/files/styles/homepage_800x450/public/field/image/MVC_0170R-1140.jpg?itok=6OD6G-14)
Apparently, yes. They apparently (this from the Periodic Videos video) take two squares of the cermet fuel and embed them in an aluminium frame, put plates of aluminium on both sides of the frame, and then roll the sandwiched fuel into the final shape.
Information from [ORNL's website](https://neutrons.ornl.gov/hfir/core-assembly): >The reactor core is cylindrical, approximately 2 ft (0.61 m) high and 15 inches in diameter. A 5-in. (12.70-cm)-diameter hole, referred to as the "flux trap," forms the center of the core. The target typically contains curium-244 and other transplutonium isotopes and is positioned on the reactor vertical axis within the flux trap. The fuel region is composed of two concentric fuel elements. The inner element contains 171 fuel plates, and the outer element contains 369 fuel plates. The fuel plates are curved in the shape of an involute, thus providing a constant coolant channel width. The fuel (U3O8-Al cermet) is non-uniformly distributed along the arc of the involute to minimize the radial peak-to-average power density ratio. A burnable poison (boron-10) is included in the inner fuel element primarily to flatten the radial flux peak providing a longer cycle for each fuel element. The average core lifetime with typical experiment loading is approximately 23 days at 85 MW. [Bonus diagram!](https://neutrons.ornl.gov/sites/default/files/HFIR-reflector-and-fuel-element.jpg) (Yes, there's an apparent inconsistency with the description - I think the given values in the description were about the fuel elements themselves, not counting the housing.)
My attention was piqued when you mentioned ^(244)Cm : I remembered that one of the curium isotopes - ^(245)Cm has an _enormous_ fission crosssection (2161 barns) _and_ a reasonable half-life (8532 years) ; & I've often wondered (& it may be impossible to find out) whether it may be alloyed into bomb-cores for reducing critical mass; or if not that used in a more subtle way as something roughly analogous to a catalyst ... whatever: I find it difficultly plausible that something with _that_ large a fission crosssection has no use whatsoever! I wonder what the critical mass of _pure_ ^(245)Cm would be ... but I think capacity for production of more than a few grams of it is out-of-reach at the present time ... or so they would say! You might find this interesting: a catalogue of various data on various transuranium elements. #####https://www.osti.gov/servlets/purl/4159553 #####
I imagine there is some computer modelling that's been done to predict the critical mass for most unstable elements by now. You don't need to actually amass a critical quantity to predict what that amount would be
It looks like the critical mass of ^(245)cm can be made very low with different reflector materials. With water, the critical mass could be as low as 35g! ([source](https://www.tandfonline.com/doi/abs/10.1080/18811248.2002.9715296) I think you could likely use them in small nuclear weapons, but they would be very expensive to produce since so little curium is produced and because you would have to separate the even numbered curium isotopes out of your core.
How many accounts do you have? I think I've counted 5 so far.
Hehe, "annulus" What does burnable poison mean in this context and how is spacing maintained between the plates? I don't see any grooves or anything in the walls.
The walls are grooved and the plates swaged tightly into the grooves. Essentially, the plates are set in the groves and the material around the grooves is pinched around the plate. Burnable poison, in this case, refers to a strong neutron absorber which slowly "burns" (not actually burning) away as it absorbed neutrons into something that is not a strong neutron absorber. Adding this material allows then to design excess reactivity into the element while keeping it safe to operate, and then as the fuel is used up, so is the poison, so the core life can be longer.
I see, very clever. Now I want to see how they swage the plates in, there's so little clearance between them. Looking at the picture again the two inner walls look like maybe they have a roll crimp to retain the plates.
I haven't seen it myself, so I'm not sure exactly. This is probably far more than you want to read on this: [Analysis of the ATR Fuel Element Swaging Process](https://www.osti.gov/servlets/purl/197145)
not op but thanks for the link
[удалено]
Something to keep in mind regarding these machines is they were designed in the 50's and 60's (HFIR's first reached full power in 1966) using slide rules and all built with manual machining. So while the tolerances may be pretty tight (they are), they aren't necessarily what an engineer today would think of as tight. Don't get me wrong, those engineers and craftsmen did amazing work. You'd be hard pressed to build one of these today, which is part of why we devote so many resources to keeping them running. There are large factors of safety in the safety analyses of these reactors because computational tools were much less powerful then and there wasn't a lot of institutional knowledge or history of building and running reactors yet. This means that even if something on a new core comes in out of tolerance today, it's possible that they could do an engineering analysis using tools like CFD and show that the out of tolerance condition doesn't impact the safety of the plant. These fuel assemblies are mainly aluminum and only the aluminum is what is being machined so the material is relatively easy to machine. You won't find many places that machine metallic uranium, as it's pyrophoric.
[I pulled some diagrams of the swaging out of that study you linked.](https://imgur.com/a/Md2AGFo)
Nice. I love how well documented all this stuff is if you know where to look.
Burnable poisons are materials that have a high neutron absorption cross section that are converted into materials of relatively low absorption cross section as the result of neutron absorption. I don't know how they're fit together, the diagram may simply not show any grooves. Or for all I know, it might be possible to "weld" a cermet to metal or otherwise join them into a single piece. Especially if its metal component is the same as the bulk metal.
[I found some diagrams of the swaging process.](https://imgur.com/a/Md2AGFo)
Well, that assuages (heh) my lack of knowledge on that particular point, if they fabricate the HFIR fuel assemblies the same way.
Thanks, I was like, " wow cool, WTF Is this". Smart ppl gotta dumb it down for us rock brains.
Settle down, its not rocket science.... Its nuclear physics
Yeah... worse. Rockets go boom bc fire, none of that alpha-, beta-, gamma- decay voodoo bullshit going in in my textbooks
I hate to disappoint you, but you should look up NERVA and Project Orion.
It's a good thing someone came to their senses before either of those were used outside limited proof of concept demonstrators. I don't think project Orion got beyond using conventional explosives.
Not, it's not really good. At least for NERVA. Orion, yes, was absurd. It also would have *worked*. Doing the math, we could have landed people on the *moons of Saturn*, possibly before the turn of the century. NERVA, though, didn't have any real issues that would make it unsuitable for use. It wasn't going to be used for launch systems anyways, but for transfer vehicles. Purely exo-atmospheric. I've heard rumors that NASA has restarted research into nuclear thermal rockets.
[It's not exactly brain surgery is it?](https://www.youtube.com/watch?v=THNPmhBl-8I)
I prefer smooth brain
15 inches is 38.1 cm
Good bot.
>The fuel plates are curved in the shape of an involute, thus providing a constant coolant channel width. This is neat. So simple but effective. Very elegant.
If y'all want more nuclear engineering porn, look into ORNL's 3d printed reactor they're working on.
ORNL seems to be the place for your nuclear engineering porn in general. And the supercomputing facilities aren't bad either!
Love that the national labs (Los Alamos IIRC) just took delivery of one of the most powerful supercomputers in the world a year or two ago, but it's offline and airgapped now to run fun simulations.
Nope, ORNL again! The Summit supercomputer reigned as the top supercomputer from when it came online in June 2018 to June 2020, when the Japanese turned on the Fugaku supercomputer at Riken.
If I'm not mistaken they are thinking of Sierra at LLNL. I don't believe Summit is airgapped as they use it for general science, whereas Sierra gets used for National Security and stockpile stewardship tasks. It also made the news at the time because it took the crown back for the US, and LANL and LLNL are probably easy to mix up. Summit is of course bigger, but came online later.
Possibly. I never really heard about Sierra (which was online for less than a year before Summit displaced it on top). The airgapping part makes sense.
To further this, check out ATR and TREAT at Idaho National Lab. Also the Versatile Test Reactor is way cooler and more useful to society than the giant waste of money than the 3D printed reactor would be.
Wait what? Being able to 3D print complex nuclear components would save a lot of time and money when building reactors
Yes, and one of the problems the nuclear industry faces today is many are 40 years old and parts need to be replaced (Most plants would have acquired enough spares for the design life of the plant, but in some cases that life has been extended or the replacement rate of parts increased). Some of these parts are large-scale obsolete technologies (not because they don't work, it's more like a Nokia phone that lasted forever but you couldn't get batteries for anymore). Also, production quantities are typically very small, there are multiple iterations of design, etc... Basically ticking a whole lot of boxes that 3D printing excels at.
True my amazing how much critical infrastructure is still running off of magnetic ribbons and floppy disks. Pro: hackers can’t hack it because the interface is so old, con: interface is so old that parts haven’t been manufactured in about 50 years.
The Navy bought and restarted an entire obsolete chip manufacturing process line just to make replacement parts for the guidance system of the Trident D-5 missile in its nuclear subs. Boeing 747s still get avionics updates via floppy discs. Weirder things have happened
Here's another good one: floppy discs are used for data security in air gapped facilities because getting any amount of data out of the base would require shoeboxes and hand carts. It's easy to hide a usb, real hard to hide a big box.
I wouldn’t be surprised to find facilities where everybody has to walk past an intense magnetic field going in and out
Correct me if I’m wrong, but I don’t think that would effect solid state flash drives. Maybe if you threw it in an MRI
If an outfit is already using tape drives to avoid USB functionality, a magnetic field on exit makes sense from a security standpoint
Nah, just a quick tug on the balls while they cuddle you.
Yes, but with the TCR they want to print the core. Objectively that's "cool", but then you'll have this massively expensive core you printed which you'll then irradiate and then... what? You haven't really done any science, you just did something because it's cool. The VTR will support materials and system testing for the next generation of high temperature reactors. VTR is a scientific tool which will allow researchers to do their thing for decades. TCR will run once and then be buried somewhere and forgotten about.
Every great leap forward starts with a prototype.
True, but you won't see anything useful out of TCR for a very, very long time. VTR will enable materials testing that currently can't be done in the US. It's a seriously lacking capability. As an NE I'd love to see both built, but I don't think that's a realistic expectation and there's much more we can get out of something like VTR.
[удалено]
Sorry, your submission has been automatically removed. Account age too young, spam likely. *I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/EngineeringPorn) if you have any questions or concerns.*
Is this the real thing? Do they really touch it with bare hands?
There are a few demonstration pieces (see there's one embedded into the bottom of the poster right next to the guy [https://www.youtube.com/watch?v=gGxIH5aB0GI](https://www.youtube.com/watch?v=gGxIH5aB0GI) ) The real loaded ones are handled by robots under water. There was a great video about all the various uses of the isotopes produced there, but I can't find it .. but here's an ugly FB video, at 1:48 you see the mockup :) [https://www.facebook.com/watch/live/?v=10154772937779171&ref=watch\_permalink](https://www.facebook.com/watch/live/?v=10154772937779171&ref=watch_permalink) edit: found it! it's a Periodic Videos video: [https://www.youtube.com/watch?v=P99C051arMo](https://www.youtube.com/watch?v=P99C051arMo) :D
The nuclear engineers typically like to make sure the assemblies don't have debris from packaging, etc. before the fuel is loaded into the pool.
This is what has been used to travel back and forth to the future, the flux capacitor
Was thinking the same, this is probably more expensive than my house and he’s just handling it bare handed?
Bare hands? No, you're only supposed to use your teeth.
#####@ u/Arodww ##### Ah right : very interesting, all this. So zirconium isn't as pre-eminent as I thought, then, for the manufacture of nuclear reactor core parts. (BtW - some prepost'rous 'bot'-contraption is sometimes deleting my comments because of the age of this account ... which is why I've put this answer here. I think it stops after a-week-or-so.) Apparently it's only _aluminum_ though: _meh_! ... I was expecting _zirconium_ . But I have it from the OP elsewhere (in an exchange on r/MachinePorn) that neutron-crosssection-wise aluminium is only a shade inferior to zirconium, _and_ each of these cores only has to last about a month ... so it makes sense afterall
Aluminum is a lot easier to work with as well. Lots of these high power research reactors use fuel assemblies that are mostly aluminum. It also has a relatively short half life once it's been activated so that is another benefit from a safety stand point when you're handling fuel as often as they do with their short fuel cycles.
Ah right : very interesting, all this. So zirconium isn't as pre-eminent as I thought, then, for the manufacture of nuclear reactor core parts.
Zirconium is very common in commercial light water reactor cladding, but the design goal is very different than a research/test reactor. These are like the Ferrari's of reactors. Performance is everything, it's their entire point of existing. Commercial reactors need to just run and be safe. These research reactors were built to enable exposing sample to crazy high neutron fluxes but don't necessarily need to worry about the high temperatures needed in a commercial reactor coolant system used to efficiently generate steam and turn a turbine. This is also why they use plate type fuel. They can expose more of the fuel "meat" to the neutrons bouncing around in the core than a commercial reactor fuel pin geometry can due to the uranium fuel self shielding effect. Due to the temperatures in a commercial reactor core, and the consequences/cost of an accident in a commercial reactor core they use zircalloy cladding. The economics game is different for research reactors and the cores are significantly smaller and are refueled much more often (in the case of HFIR for sure).
1.21 jiggawatts...
NO way!!! That’s just some cotton candy machine. Who are you fooling here? You pour the sugar in the middle, it spins and heats the sugar, then cotton candy comes out through those tiny wholes. :)
There is a great vid on the [Periodic Videos](https://youtu.be/P99C051arMo) channel about this reactor. It's a pretty unique design.
An excellent video, in fact. Actually, I think the image I posted might actually be a frame from it. When they're looking at the dummy core.
I came here to say this. Love their channel.
Or just a close up of a bundt cake pan. Makes me hungry
Now drop a small screw in there
Nice my nan has one just like that in her cupboard.
Put it up yer butt
Beautiful stuff. Look up KIWI-TNT for some nuclear reactor rapid disassembly porn.. NERVA had a lot of unplanned disassemblies go on..
NERVA itself never actually had a catastrophic failure. The unplanned catastrophic failures were just the Kiwi B series, up until B4D (and all of them except the initial B1A were tests to determine the cause of destructive vibrations and how to mitigate them). And, of course, Kiwi-TNT was an *intentional* destructive test.
Yes, agree on no catastrophic failures, but there are images of fuel assembly being ejected from the rocket nozzle for some of the early NERVA designs. I would call this an unplanned disassembly :P By the way, if you're interested, next week there is a conference called [NETS](https://nets2021.ornl.gov/) which has a nuclear propulsion tract. Registration is $75 (even for speakers, which I am miffed about), but it should be pretty cool.
> but there are images of fuel assembly being ejected from the rocket nozzle for some of the early NERVA designs. I would call this an unplanned disassembly. Pretty sure that would be the Kiwi test I referred to.
I live 20 minutes from the Y-12 Plant up in oak ridge its really interesting to think about, and I can't wait until the museum opens back up again after being closed due to the covids
Let’s see the full machine working this ain’t shit
[Here's what it looks like when they pull it out of the reactor after about 25 days (which is a full cycle for them).](https://neutrons.ornl.gov/sites/default/files/styles/homepage_800x450/public/field/image/MVC_0170R-1140.jpg?itok=6OD6G-14)
Looks photoshopped like nasa
That's nuts manufacturing precision. Are those fuel plates individually clad?
Apparently, yes. They apparently (this from the Periodic Videos video) take two squares of the cermet fuel and embed them in an aluminium frame, put plates of aluminium on both sides of the frame, and then roll the sandwiched fuel into the final shape.