Nuclear Reactor Pulse

[Gregiorp]

I dont get it what am I..(00:12)...WOAH AWESOME

[ApolloWasReal]

As I understand it, these pool-type reactors use uranium hydride as the fuel. UH reactors have a very negative temperature coefficient, meaning they essentially shut themselves down instantly when they get hot. This makes them unsuitable for generating power, but they're ideal for teaching or for producing isotopes by neutron irradiation. Chernobyl had several positive feedback effects that all combined in a perfect storm that made all the difference.

[NFLization]

I'd hate to be in that room while it's pulsing.

[bi0hazardous]

That blue pulse is a clear example of Cherenkov radiation right? Because I know in the spent fuel bays in reactors there is a permenant blue colour in the water from this effect.

[ProxyNuker]

There is a BIG difference between a nuclear reactor and a nuclear bomb, a nuclear reactor will never create a gigantic nuclear explosion.

At most hydrogen or steam explosion.

[x65535x]

@ProxyNuker

Yeah, but when those pressure vessels burst it isn't a small explosion, then you have to deal with potential aerosol nuclear material, it's just messy.

[navsquid32]

More correctly... prompt supercritical.

[dekkkaimara]

May I as how dangerous the radiation is? The blue light mean neutron is also coming out ? Im kind a surprised that you guys are not wearing any protective gear or mask

[pyro637]

@dekkkaimara Its no more dangerous that the radiation you receive from standing outside in the sun.

[dekkkaimara]

@pyro637 is it because the amount was so little? besides water is protecting from radiation? sorry Im kind a noob

[pyro637]

@dekkkaimara Yes, the water does protect you from much of the radiation, but the main reason is that the duration is so short. It would be dangerous for you to be in that much radiation for an hour or more, but since it only lasts a few milliseconds it is very small.

[ApolloWasReal]

@pyro637 Water is actually an excellent shield against neutron and gamma radiation, as long as it stays liquid. If the reaction produced considerably more energy the danger would come from the water getting too hot and boiling, not from the radiation making it through the liquid water.

[glukaschlok]

Indian guy accidentally goes to underwater cross burning ritual.wmv

[Sturmkanone]

all attendants are now impotent !



[TheAcehd]

MAXIMUM POWAR

[douro20]

What series Triga is this?

[danilomazzanti73]

scusate, ma cosa si intende per "pulsazione" o "pulse", riferita ad un reattore nucleare? accensione? cambio del livello di potenza? o accensione conseguente alla fulminea estrazione delle barre di controllo? non capisco come possa verificarsi un fenomeno apparentemente brusco come quello nel video... grazie.

[emercito]

Is the light saw here the same, released an atomic bomb?

[qbasic16]

@emercito no, the light in the reactor is called "Cherenkov radiation" ;)

You can find an article on Wikipedia about that.

[TheGodParticle]

0.38 Hello, i am hans and i would like to sleep with your wife.

[flashkillerffff]

im sorry my friend but from now on if you want kids ,you'll have to adopt

[YousefsPie]

If someone was to jump into the water when the pulse happens what would happen to them?

If I did do I would be scared so shitless. Wow just wow.

[AirsoftShenanigans]

@YousefsPie That would scare the shit out of me. If it were a glowstick, it would be awesome, but since its's radioactive, the thought of possibly losing any future children scares me.

[GIRLIKESTACOS]

@AirsoftShenanigans Forget children. You wouldn't be able to survive the pulse if it went off.

[sweetness00peace]

@GIRLIKESTACOS looooooooooooooooooooooooooooo­l

[powerfulpup]

So they remove control rods, which results in the pulse? Then almost immediately re-insert a control rod to absorb some neutrons to slow the reaction back down? Is that basically what this is, or am I way off?

[soylentgreenb]

@powerfulpup Way off. They kick the control rod out and don't put it back in until the pulse is over.

Reactors are not bombs. If you insert a little bit of positive reactivity the power does not rise forever. There is thermal expansion, there is resonance broadening and other mechanisms reduce reactivity as a result of the rising temperature.

This particular reactor is designed to gracefully handle a HUGE insertion of reactivity, with very strong negative temperature coefficient of reactivity.

[jonydictado]

Why does it bright with that blue light?

[RadioAnarchia]

@jonydictado Cherenkov radiation

[ZXLNT]

@jonydictado Thats called Cherenkov radiation. It's caused when a charged particle travels faster than the speed of light in that medium. In this case, the charged particle is probably an electron and the medium is water. The speed of light in water is only .75C. The electron travels faster than that. When it falls back to its ground state it releases light which you see as the blue glow..

[Triethylborane]

sounded like JFK or ted kennedy was on the mic

[spanizzo84]

Chiara dimostrazione dell'effetto Cherenkov!!

[raist20]

Lol, mate if it was an nuclear explosion, how did you post that video on youtube :D? It is not explosion. It is prompt critical effect. For 1 second, you see power increase and thats all. It is normal operation of test reactor. Already you had given a good name for your post, dont scare people with the wrong information.

[ironcross44]

@raist20 nicely put. Also the U235 and byproducts of the fission process would never sustain a nuclear explosion. The uranium used in reactors has not been enriched nearly enough to be weapons grade. Plus, there is nothing to drive the U235 into itself fast enough to cause it to react in such a way.

[ApolloWasReal]

@raist20 I think the prompt critical period lasted much less than 1 second here before thermal expansion and Doppler broadening brought the reactivity back down. The glow lasts longer because you're seeing the decay of the short-lived fission products produced in that very brief fission pulse. Most fission products are beta emitters; beta particles are electrons and they're energetic enough to move faster than the speed of light in water, hence the Cerenkov effect.

[wog222]

@ApolloWasReal are beta particles really "bad" to come in contact with?

[ApolloWasReal]

@wog222 Beta particles are just energetic electrons. Any charged particle can be ionizing if it's energetic enough, as these are. That means it can rip up molecules like those in your body. Fortunately, beta particles are so ionizing that they quickly give up their energy when they hit something -- even air -- so they can't penetrate very far. So as long as the beta-emitting material is outside you it's not very dangerous. But if it gets inside you, then it can be pretty bad.

[ApolloWasReal]

@wog222 Beta particles are just energetic electrons. Any charged particle can be ionizing if it's energetic enough, as these are. That means it can rip up molecules like those in your body. Fortunately, beta particles are so ionizing that they quickly give up their energy when they hit something -- even air -- so they can't penetrate very far. So as long as the beta-emitting material is outside you it's not very dangerous. But if it gets inside you, then it can be pretty bad.



[ApolloWasReal]

@wog222 The real hazard from both a nuclear reactor and spent nuclear fuel is their gamma radiation. They're photons, just like light and X-rays, except they're far more energetic than even X-rays. What makes them dangerous is that they're ionizing but not TOO ionizing. So it takes heavy shielding to absorb enough of their energy to protect people beyond. Fortunately, water is a very good shield that's also cheap, transparent and easy to store and move.

[wog222]

@ApolloWasReal Thanks for your reply's. That is interesting to me that water is used for shielding and for cooling. Oh, and also steam. I assume that is why the nuke plants are near water.

[ApolloWasReal]

@wog222 Most nuclear plants are near large bodies of water (lakes, oceans, rivers) not because they need water to make steam for their turbines. That water is easily recycled. The real reason is to increase thermodynamic efficiency, the fraction of reactor heat energy that becomes electricity. The hotter the steam and the cooler the condenser, the greater that efficiency. Since about 2/3 of the reactor heat is still wasted, that's a LOT of cooling water!

[ApolloWasReal]

@wog222 Many (but not all) reactors use water for yet another purpose: neutron moderation. That slows down the neutrons emitted from fission to make them more likely to trigger another fission. That's actually not the case in this research reactor; the moderator is the hydrogen in the uranium hydride fuel. The fuel heats it instantly, unmoderating and slowing the reaction. That's what makes pulsing this reactor safe. It'd be very unsafe in a reactor with a separate moderator.

[wog222]

@ApolloWasReal That is cool - there is so much more to reactors then I ever would of thought. So if you pulse the wrong type of reactor you will have a bad day.

[ApolloWasReal]

@wog222 Yes indeed. Reactors differ enormously in their various 'coefficients' - whether the reactor power tends to go up or down as it heats up, runs dry of coolant, etc. Chernobyl had numerous design flaws and incompetent operators unaware of the safety rules. It went supercritical and the power shot to ~100x normal. These research reactors have very strong negative temperature coefficients that make this impossible, but they're not useful for power generation for the same reason.

[usbiker133t]

Not an explosion, supercritical is normal. Don't make people scared please.

[kpshc707]

that's a little slow for a explosion

[Garrett85]

Questo effetto si chiama effetto Cherenkov ed è del tutto simile alla generazione di un onda urto da parte di un corpo che supera la velocità del suono nell'aria.

[Garrett85]

Il reattore è concepito in modo tale da avere un coefficiente di reattività negativo all'aumentare della temperatura di esercizio in modo da auto arrestare la reazione e spegnersi. Il lampo blu è dovuto ai raggi beta (elettroni) che superando la velocità della luce nel mezzo (acqua) cedono parte della loro energia cinetica sottoforma di radiazione luminosa azzurra.

[Garrett85]

E' un reattore affogato in una piscina d'acqua leggera in cui vengono rimosse simultaneamente tutte le barre di controllo in modo tale che la reazione di fissione nucleare possa procedere in maniera molto veloce raggiungendo picci di potenza dell'ordine di 600MW in qualcosa come 50 millisecondi.

[Garrett85]

E' un reattore nucleare didattico presso un università statunitense.

[riccardobevilacqua]

Tutto corretto quello che scrivi, Garrett85, tranne una cosa: il reattore dove ho girato questo video si trova a Vienna! (ma ce n'é uno uguale anche a Pavia, tuttora funzionante!)

[Garrett85]

Non sapevo che esistessero anche in Italia!!!!!

[elydeda81]

Cos'è sta roba????

[Alcamps]

riccardo puoi spiegare cosa è successo in poche parole :| io vedo una luce ma non capisco cosa sia successo

[brescialeonessa]

Invitare qualche ministro italiano per una BREVE immersione? ;-)