NaK 

You guys really have a nak for chemistry.

So you're telling me they built a sodium potassium pump?

We deal with this at my uni, people with parasitical nonresearch nonteaching positions dictate to working scientists what is safe despite having less understanding than the scientists they dictate to. All this does is reduce training in how to make experiments safe and so, ultimately, reduce safety.

If I were choosing a uni to do chemistry at I would partly base my decision on how unsafe an experiment I was allowed to do. If I caught fire on the campus tour I would pick that uni for sure.

"Destroyed"... uh huh. Let's not ask Steve what that bubbling noise is coming from his basement.

It's truly unfortunate that science is being limited these days. At our school my chemistry and biology teachers told us about experiments they used to do that were really fun. But now we can't do them because of "safety reasons". If no one gets hurt and care is taken why not do them? Proper handling of dangerous chemicals never hurt anyone, just as the professor said with the liquid sodium.

I think I just found my next GPU cooling system.

It would be interesting to see 1) how the NaK alloy was created and 2) the process used to seal it in the apparatus without exposing to air.

in the company I used to worked for we saved historic pieces by getting the management approval for destruction and then bringing it to an unspecified "disposal company". At the end of it, it was in a private basement. Management of course did not know but also not care as it was out of the way. Of course, in this case they must prove that the NaK gets disposed safely at with all papers, but the pump it self could be "disposed" by bringing it to a "metal scrapper" but never arriving there.

There's quite a lot of NaK apparently floating around in space. It was used as the coolant for the reactors that powered a number of Soviet satellites- called RORSATs; a total of 31 were launched between 1967 and 1988. When they reached their end of life, the satellites were sent up to a higher 'graveyard' orbit and the reactor core was ejected into space. In most cases, this process released the coolant which continues to orbit the Earth.

Mechanical pumps where used with NAK in the reactors. If I recall they used cryogenics to freeze NAK and use the frozen NAK as a bearing surface. Clever but unreliable and leaks were common.

The Sov's had NaK- or Sodium-cooled reactors on a few subs and power plants. They had a few accidents and "oops" incidents involving maintenance of the coolant loops. One or two reactors had to be literally disassembled due to someone shutting off the heaters and the metal coolant solidifying in the pipes, causing damage to the system. A couple of explosions due to sodium leaks forced the Sov's to discontinue using the liquid metal and settle for water/barium solutions in a PWR setup.

4:09 Induction pump motors based on this principle, but not the same materials, were first invented by Einstein & Szilard to replace the toxic SuO2 in the refrigerators of the late 1920's

Oliver Sachs in his autobiography Uncle Tungsten described how he and his friends (young boys) contrived to get a lump of sodium the size of a loaf of bread. Naturally, they cycled to the local park and heaved it off the bridge into the duck pond with a predictable outcome. He did not say what happened to the ducks. Every boy dreams of this kind of chemistry. Glad to see your programs as you are able to do these things and neither man nor duck is harmed.

"I need to demonstrate something really quick. I think I'll just grab some of my award trophies and use those." Yep, that's Sir Martyn for ya.

Have you considered doing a subseries of chemical instruments and/or tecniques on this channel? Hearing the professors talking about MS, NMR, IR etc would be interesting!

Professors Steve Howdle looks like a young version of Martyn.

NaK is back, babyyyy! Game of the year!

My brother is a chemist and when he was doing his PhD, they had another chemist in the lab nicknamed Char Dog. They had flasks of NaK in kerosene (if I remember right, it was something like that) all over the lab. One shattered and splashed him, he went to the eyewash station, which ignited the NaK and thus the kerosene that covered him. He had some scarring but was otherwise more or less okay.

NaK is back baby

And the reason we like to use NaK in fast reactors is that it is basically transparent to neutrons. With things like water, neutrons end up bumping into them and slowing down or being absorbed quite a lot. With NaK, the absorption and bumping is pretty minimal. NaK was what we like to use in the west for fast reactors, while the Russian's favored using lead and lead-bismuth alloys. There are advantages and disadvantages to both, Lead might not react with the air like NaK, but it is super heavy and can also be corrosive at high temperatures and flow rates. Lead is also a solid at room temperature which means you have to worry about your coolant freezing and clogging things up. We favor NaK in the west as a result, even though it can be explosively reactive. Which is better is mostly a matter of what you are attempting to design for.

"They got rid of it" - We want a video of the decision makers! :D

Wish we had this guy teaching chemistry when I was at school. I might have paid a bit more attention and spent less time washing sodium hydroxide out of my mouth.

Always heard of sodium-cooled reactors, but never understood the principle behind it... thanks!

The best safety is solid working knowledge. If you cannot teach or work with something because it is "unsafe" then that in itself is creating the safety issue by lack of knowledge! Keep up the Excellent videos Professor!

Hello! I beg you to please activate spanish subtitles. Every hispanic kid and boy should see your videos. Thank you and greetings from Mexico.

I swear the health and safety bureaucrats will bring about the second dark ages 😒. How are we meant to inspire the next generation if all the interesting stuff can't be shown! Thank you for having the common sense to record it before it was disposed of.

A pump with no moving parts, beautiful. Still I'm amazed they never eventually had a leak with it, the consequences would be unfathomable. How would you even explain that to the fire crew?

There are a few metals that have a low mp. Gallium has been mentioned. Density 5.91 g/cm3. There is also Wood's metal. There is Gallinstan (gallium, indium, tin alloy) that you find in new thermometers.

The NaK fountain operates by using (reversed) MHD (MagnetoHydroDynamics) as a motor. Was wondering, to get better views of 'bangs' if NaK could be dropped while in an container filled with dense inert gas into water or have it bubbled in through a thin pipe underwater? Plain Na or K can be used, if apparatus is kept warm enough, if liquid contact is desired.

What an *awesome* device (and video)!

This is the best title I have seen on RU-vid.

It would be very interesting to find out what kind of metal piping could be used for NaK, as well as what could be used for piping gaskets.

I had one week of winter break in my 1 year Bachelor of Science chemistry studies and used it for binge watching periodic videos

Could you make a video explaining why two solid metals make a liquid alloy? Seems like a bit of a mystery to me.

Why does a alloy of solid Na and solid K become liquid?

There are types of coating you can apply to glass, to make it so gallium doesn't stick to it. That means, if you also introduce a little heating coil, you can safely make this apparatus using gallium as the liquid metal.

Are the electrodes in actual contact with the NaK? Do the electrodes pierce the glass container? If so, how does the NaK effect the electrode tips? And if not, how does the current effect the system at all?

I so love all your videos. Thank you all.

This channel has a NaK for producing interesting content.

I recently (bout 2 weeks ago) found this amazing channel and I feel it would be the perfect place to ask about oklo where several natural nuclear fission reactors were found. I was hoping you can do a video on that and maybe get the professors views on Nuclear power and its hopefully bright future?

First to comment who bothered to watch the video before commenting ;) The apparatus should have been kept, but with no NaK in it.

Excellent video, it is well made and stays on subject without straying.

Hi Sir Martyn I couldn't help laughing the compound NaK was chosen because very high heat capacity a little above Aluminium but the fast breeder reactors had problems of leaking under great pressure meaning the Nak just spontaneously combustion creating fires so that's the reason most of the Europeans had to close all there FBR programs. The only solution is to use D2O yes its expensive but safer even with a cloak of graphite surrounding the U238 blanket, the graphite slows the neutrons to bounce back into the blanket of U238 to produce Pu 239 .

it would be nice to talk about the connection between temperature, re-activity and corrosion and how corrosive a substance is is actually relative to what it is contained in such as how a FliBe molten salt (though normally corrosive) can be managed inside a Hastelloy N or related alloy. o/

Should be Natrium and Kalium. That's why the symbols are Na and K.

Another alloy that's liquid at room-temperature is a combination of Gallium, Indium, and Tin, which is sold under the commercial trade-name of Galinstan. It can be left exposed to ambient air without being hazardous to people, but unlike mercury, it wets glass (it sticks to glass) and porcelain, and human skin, which makes it almost as much of a hassle to handle as mercury's toxicity makes it to handle.

Could this work for FLiBe (Lithium Fluoride Beryllium Fluoride)?

have you guys done a video of thorium? and how people say its the power of the future.

I've seen that red and yellow magnet from inside the apparatus in another video where the professor is using it in a classroom demo! I like that magnet.

Great video, I'm a chemist and I never even knew about NaK!!!

This video is very apropos for me. I'm taking a summer physics course and we just started talking about magnetic fields today. We're told to use the right hand rule rather than the left. Now I'm curious if it's taught differently in the US vs. UK, or if it differs everywhere.

So... is NaK attracted to a magnet? as well as being conductive?

The Soviet era Russian Navy used "liquid" Sodium coolant in the reactors of the Alpha class SSN's in the 1970's which gave them huge power out of small reactors ( the Alpha class was the fastest ever built nuclear powered submarine at 47+ knots ( 54 mph ) but with the huge disadvantage of being heard by old sonar sets several thousand miles away , also the huge problem that they had to use a shore supplied steam feed to keep the Sodium liquid as once the Sodium cooled to a solid state the reactor was beyond being saved and had to be removed and scrapped

"Too dangerous" Riiiiiight.. Stop fighting in wars then mr government man.

Are these videos flipped? Why are you guys using your left hands for the right hand rule?

Does it react with copper of aluminium? I am tempted to try cooling a PC with this...

How do you get 2 elements right next to each other, that are extremely reactive too, to stick together??

I was going to suggest if a higher temperature was used, gallium might be suitable, but as I recall, it wets glass, does it not?

Wasn't there a proposed electricity generator that used NaK (or maybe just pure Na or K, I can't recall anymore) where you had the loop of liquid metal, and the magnetic field, but then hated it and used the heat to cause circulation around the loop, and used that to generate electricity?

If Sodium-Potassium alloy called NaK, is steel something like FeC?

I prefer right hand slap rule rather than left hand grip rule, because it can be related to the right hand grip rule, as the thumb is the current for both :)

This blew my mind. I've been on holidays too long, got me keen to go back to uni.

UH OH, DID SOMEONE SAY NAAAAAAAAAAK????!?!!!!!!

Oh that is so cleaver. To make a NaK pump with magnets, I never would have thought of it.

Would this not be possible with gallium? It's a light element, so would still work, but is (as far as I'm aware) non-toxic. Might need to do it in a hot room/use mild heating pads, but it would be an excellent demonstration piece to show how the original experiment worked.

Would it be possible to use a coil of wire surrounding the base of the tube instead of having to lug the 2 large magnets around? You could use a lower current and still achieve a stronger magnetic field theoretically via this inductor configuration.

What is in the bulb in which the NaK fountain is located? An inert atmosphere or a vacuum? I don’t mean the argon filled bell jar.

Question,2V@40A is 80Watt How did you got rid of that heat? Or did you run is short times to not get to much heat in that system? Like that mercury idea :D The multiple "motor" set works and at most needs external cooling to adsorb the heat produced in the mercury resistor. IT can be done dudes! When the set-up is really big it doesn't even need forced cooling well almost not,we still need some fans or .chiller to chill execs heat. after long runs. Big is as large as the jar that contains the original experiment.

7:02 It was a NaK-t of vandalism

Dear Steve and Martyn, do you think that Lithium-Potassium deuteride could be used as fuel for a hydrogen bomb, much like Lithium deuteride was used in Operation Castle Bravo? I wonder of this could be a better manifestation of an electro-magnetic pulse which the nuclear devices are famous for.Thank you for your answer.

When will this compound evaporate? A bit of online research didn't give me a clue, making me believe it would somehow decompose when reaching a critical temperature?

What about gallium or a gallium-indium-tin alloy? Though of course you'd have to coat the inside of the apparatus in gallium(III) oxide for it not to wet the glass.

7:50 why not with Gallium tin Alloy ?

Is the area inside the glass dome filled with argon, or was he saying that the place where the spout is at is filled with argon? Or both?

They use NAK in high end oven thermostats whenever I replaced one they always send an explosion proof bags... Which never get used because I take them apart and play with the NAK.

Mercury does not need any pump to circulate in such situations. As a metal, Mercury expands inside the reactor and with one way valve in the circulation line, forced to move in one direction where it cooled by the heat exchanger. The more the reactor temperature, the faster mercury moves.

Other than the glass in the display pump, what metals were determined to be non-corrosive when exposed to NaK during testing?

How are samples of metals introduced into the system to test whether they will corrode from the NaK or not?

😱 Left hand rule! ... Over here we use the right-hand-rule. Thumb for current, fingers for magnetic field, and palm for force. It corresponds with the right-hand-rule for finding magnetic field caused by a current, where the thumb is again the current, and the curl of the fingers indicate the magnetic field. Is this another UK vs. North America thing? Also, I thought from the title that this must be a computerphile video, but checked the channel when I noticed the lowercase 'a'.

could have wrapped a coil around it then upped the voltage to increase the force safely for the mercury. really interesting stuff, thanks for posting.

So what was the result of the experiment? Does NaK corrode the metal pipes?

If I have many alloys, and they are all not marked... is there any way to safely determine the one NaK-ID? >....< I'm so so very sorry, I couldn't resist... I'm so immature sometimes :D

My cousin, a retired chemical engineer for an oil company, told me they used NaK by the tankcar.

This same principle is used to pump molten solder in electronic industry soldering machines

What about Cs-K-Na?

+Periodic Videos instead of NaK or Mercury you can use for example gallistan (68% Ga, 21% Indium, 11 Sn%)

Is this the same magnet that the prof. Poliakoff uses to demonstrate the magnetic propriety of the liquid O2?

To pump the mercury you just need to put the electrodes higher, so that the mercury column is shorter, therefore, less heavy to lift. If the electrodes are kept at the base, it would be too much mercury to push up. Even with a little amount, gravity will try to balance the levels and it will keep running in the same way as the NaK one was doing. But the stream of mercury will not go up too high anyway.

How does two solid alkali metals become a liquid? Does this have to do with a rearrangement in their metallic bonding from the the new alloy? Cheers.

Could galinstan be used instead of NaK for cooling as long as they aren't using aluminium piping? It's a lot safer.

I think the Soviets used NaK in their nuclear subs. There was a major problem with the speed of cooling and the density change between output and input.

Great lecture sir Martyn. Hope to hear from you again the soonest. Leo and Sofia.

What about using Gallium and just keeping the average temperature above 30C so that it stays liquid?

Are all sodium cooled reactors in fact NaK cooled reactors or are there also reactors that are cooled only with liquid sodium?

At first, I thought that this video was on a compound of sodium and potassium. That would be pretty cool, but very unlikely.

Has there been any research into materials with similar characteristics as NaK, e.g. good thermal conductivity, but not quite as reactive?

Fill one with Galinstan alloy instead of mercury. Galinstan is inert and non toxic and the density is pretty low too

They sound very sour about the apparatus being deemed too dangerous 😂

perhaps you could build it using mercury, but changing the argon for a denser and clear fluid in order to reduce the A^density. Maybe with this you could avoid to crank the amps