Lecture 13 (3.8.2021) - Rudiments of Nuclear Weapons Physics

[@iitzfizz]

There actually were 'wet' bombs designed and fielded as 'emergency capability weapons' based on the Mike design which used cryogenic Dewar flasks to store the fusion fuel.

[@Aaron-zu3xn]

couldn't they just take the flask turn it sideways and put it in a nuclear torpedo?

[@Clancydaenlightened]

Tsar Bomba did something like this Tanks full of liquid deuterium and helium With a small atom bomb or trigger nuke

[@Clancydaenlightened]

Wen ussr records propaganda of the internal construction

[@Clancydaenlightened]

Americans figured by accident they can use lye drain unclogger instead so no need for high pressure cryogenic tanks

[@Clancydaenlightened]

Ain't your normal lithium hydroxide

[@Evan_Bell]

23:00. Popular misconception. The primary and the sparkplug don't produce sufficient neutron flux to breed a meaningful number of Tritons. D-D ignition is initiated and it's its fusion neutrons that breed Tritium.

[@mutiur7396]

Don't they place tritium in the center of core... I have not seen the lecture just enjoying the comments so far😂😂😂

[@Evan_Bell]

@mutiur7396 Yeah, gram quantities of a stoichiometric mixture of deuterium and tritium are injected into hollow cavities of the primary pit and secondary sparkplug, which undergoes fusion to boost the fission yields of those components. But those also don't produce enough neutrons to breed significant amounts of tritium from the lithium in the secondary...

[@daynosdr]

this guy says 'Ugh" mega-tones

[@paulhoughton1691]

Almost un-listenable

[@abcde_fz]

. At about an hour and fifty minutes our presenter talks about Uranium enrichment in Iran, Iraq, Libya, and such. What he didn't mention is that his friend who saw the materials being trucked away in the one country also did inspections in Libya. The centrifuges, because they must rotate at incredible speed, must be balanced to the point of the margin for error being absolutely ridiculously small, like .0000001 inch in the radius of the device, so that the weight is balanced and the thing won't spin up and explode like a bomb. The fun part is when the guy was in Libya, they showed him parts of the centrifuges, but they insisted that they were being used for some mundane purpose. They tried to hide behind lies. Well when the guy was being shown the dozens and dozens of $100,000.00 aluminum central portions of the centrifuges, all he did was touch each one as he was counting them. The minute weight of the oil in his fingerprints on each unit was enough to throw the balance off to the point that when each rod was first spun up, the rods would shake themselves badly enough to make them useless from that point on. I heard the story in another video called something like "How Nuclear Bombs Work 101: Part 2/2"

[@fieryweasel]

kzbin.info/www/bejne/sIfLgoKercdkg8U is part 1 of that lecture, and kzbin.info/www/bejne/g5-6aHeuqK-nnpI is part 2. The story is mentioned at 26:50 of the second video.

[@abcde_fz]

@@fieryweasel Excellent! Your comment does allow people to see for themselves, which is better than me telling the story, as I may have gotten a detail or two wrong. Thanx!!! 🙂🙂

[@fieryweasel]

@Down The Rabbit Hole Glad to help. If you're interested in the physics of decay, etc check out the MIT Open Course Ware lectures, there's one series about ionizing radiation with a bunch of very detailed lectures.

[@GlenCooper-sj4lh]

Michael Short does a good job in the MIT OCW series.

[@Oneover_137]

Um um um um um um curious um um um um um thank um um um you um um um um.... holy hell

[@LCdrDerrick]

I've always problems with my designs. Whenever I crush the first stage into criticality, the corresponding chemical charges also destroy the shared casing with the second and third stage, but which is important as a radiation reflector to start the fusion, long before it could suit this role. I almost destroyed and irradiated seven livable planets now, but I don't come further. I've tried bigger casings, less tamper, even pits with extra layers and a floating core, to achieve criticality sooner. Do you have any tips for me please? Perhaps the Teller-Ulam design is a propaganda lie from the beginning and those bombs follow completely different principles? I've even tried to work around Pu239 and fission, using the intercept of potent pulse lasers to start the fusion. Please, I do not want to destroy and poison whole civilisations and biospheres.

[@7177YT]

What he said!

[@Nickle314]

Question 1. On the plastic, is that expanded, or just solid plastic? Question 2. The mean path of a neutron, and the probability it hits a nucleus. If the metal is compressed and so the density rises, then the length available to hit a nucleus goes down, before it escapes. How does that interaction pay out with yield? I presume it reduces it. Question 3. With explosives, what increase in density can you achieve? Fat man, levitated pip etc, how does that work.

[@ravener96]

Compression improves yield, as the likelihood of hitting a target particle also increases as the size decreases. Additionally higher compression means you'll have more time to react as you pass into and out of the higher compression levels.

[@mutiur7396]

@@Nickle314 I think more than mfp the purpose of compression is to keep the geometry... I suspect the plastic as even being present in real device

[@johanfredin5153]

Thanks! Great content!

[@Kokyiintx]

This reminds me of how conservation of energy is the bedrock that all verifiable science springs from.

[@hypercomms2001]

What about Thermal Diffusion for the separation of Uranium 235 from 238??!!

[@vibrolax]

Both USA and Japan built small scale thermal diffusion separation plants during the war, according to R. Rhodes. Not enough advantageous enough for USA relative to EM and gaseous diffusion.

[@hypercomms2001]

@@vibrolax I guess you gotta try everything when you are the first to actually attempt the separation of uranium 235 from uranium 238... What I do remember reading about the gaseous diffusion plant... That while they were contracting it... The gaseous diffusion technology for it was still being developed in parallel! I guess given it was a war on, they didn't have the luxury of having to build a pilot plant first.... They had to build the production plan from the very beginning... And sort the problems out later... I don't think any building now would get an approval on that basis.....

[@hypercomms2001]

@@vibrolax what was the principal behind thermal diffusion?

[@vibrolax]

@@hypercomms2001 www.osti.gov/opennet/manhattan-project-history/Processes/UraniumSeparation/thermal-diffusion.html#:~:text=The%20basic%20principle%20in%20liquid,between%20two%20concentric%20vertical%20pipes.

[@vibrolax]

@@hypercomms2001 KZbin deleted my reply with link. Simply search for thermal diffusion method of separating isotopes.

[@matthewrecord8371]

Actually a very valuable lecture, and clearly presented. Thank-you Professor ! Little biased for Berkeley, and too few mentions of Col U or Chicago, but that is forgivable.

[@emilkarpo]

The use of this lecture in a drinking game by anyone but the most professional and experienced drinkers is strongly not advised. Stamina is an absolute must to get through the first 10 minutes.

[@Live.Vibe.Lasers]

is the slide in the thumbnail with the neutron initiator featured anywhere in this video? If not, where might I find it?

[@martinross6416]

Ummm ahhh um ah ah ehhhh umm ah ah um umm ah um ah ah um etc etc

[@bradleyknopp7303]

Although I find any talks on these topics to be very interesting... this one is almost unlistenable with how much he says "um" "uh" "uhh" "um"... good information presented ... if you can break though the maddingly distracting ums and uhs... good god... I'll just read the transcript...

[@HappyBear376]

Emmm, eh, urr, ahhh.

[@hanniballisticbear]

I cannot listen to a lecture full of UM UH UMM UMMM UH

[@BigDaddy-yp4mi]

Never use 'uh', 'um', 'like', 'aaaahhh' when publicly speaking.

[@Metastasic]

Even the closed captions are saying “ehhh. Ummm” it’s infuriating. Please redo these lectures with a person able to speak the English language clearly. What a waste.

[@7177YT]

It's for free, you're not forced to watch it, and still you demand they redo it.wow, the entitlement. (:

[@PlasmaRayInSpace]

What are yall saying? He speaks fine, well i get it.

[@999cathou]

uh-uh-uh

[@MrYukon2010]

I find uhm, uhm, this talk uhm, lecture uhm, uhm not uhm so, so uhm ins- uhm spiring.

[@Vinzmannn]

Too bad for you

[@thedouglasw.lippchannel5546]

I'll stick with Lady Fingers

[@camresearch5120]

Teller was really smart. If I had built an exploding fusion factory, I would not be out to watch the event. You would find me also hiding in a basement far away ☀️... Not fun in the Sun.

[@darby5987]

Next time find an actual physics lecturer - someone who can speak to an audience and hold its attention. If you take out all of the ummms, ahhhs, eerrrrrs from this video you might have a 5 minute short. I wanted to hear this information but the delivery was so gawd awful that I had to fold my tent and leave after less than 10 minutes. What was NSSC thinking?

[@julientucker3395]

Tried to watch, had to shut it off . Terrible speaking skills

[@kennyhumphries100]

This is un-listenable due to the poor speaking skills of the lecturer. Very annoying.

[@robertmandell526]

Any lecturer can train him/herself to real-time edit out all the intellectual 'crutch' mouthing. These are just bad habits of casual speaking, unfortunately carried in train by sloppy thinkers. They lean on the nonsense words while their brains attempt completing thoughts. I had a Physics professor like this in undergraduate days. I brought it to his attention repeatedly after weekly lectures . He'd always get steamed, but he improved throughout the year. UCLA, PHYSICS AND ENGLISH, BS/BA, 1970.