/sci/ - Science & Math

I would think that even if something went horribly wrong, the whole thing would fly apart before any serious quantity of the fuel reacted.

Usually U-238 is used.
This atom is then splitted by a neutron.

How the reactor doesn't explode, I have no idea.

>>2607971
>>2607956
NO
it doesn't work that way

>>2607956
>yfw you realise that water is the most common form of coolant for a nuclear reactor and thus why they have those huge cooling towers though fuck knows why these figures become the poster boy of pollution when it's motherfucking steam and this is why power stations tend to be built near rivers streams etc without creating three-eyed fish as depicted in fictional cartoons such as the simpsons

And I'm fairly sure the uranium in fuel rods doesn't have anywhere near as much U235 as bomb uranium.

Whoops, got my facts mixed up.
U-235 is used mostly.

Sup OP.
While it may be fun to see a picture that I originally posted still circulating months after the posting date, I'm here to inform you that it isn't up-to-date.
Here's a newer one.

>>2608004
Sup dear impersonator. I posted these pictures on /sci/ a long time ago and all of them belong to me.

>>2608010
Sup dear denier.
Please post us an updated pic of your account to prove it, much like I just have.

>>2608010
>>2608018
dear impersonators. stop impersonating me. i posted the "new" pic weeks ago on /b/

to anyone still interested, I think graphite rods are used to absorb free neutrons and slow down the reaction

>>2608018
The one in OP is the updated picture. The one you posted is the outdated picture which I posted a while ago on /sci/.

>>2607956
Very simplistic explanation OP:

A nuclear reactor uses radioactive fuel [Say, uranium] to heat water until the water turns to steam. This steam then drives a steam turbine which provides power to people.

The nuclear fuel itself cannot go critical like in a nuclear explosion, that sort of thing requires a fair bit of energy to get the process started. A very basic nuclear bomb involves taking two subcritical masses of uranium-235, and smashing them into each other to create a supercritical mass and cause a nuclear explosion.

This is incredibly different from what is happening in a nuclear reactor.

The worst thing that can happen in a nuclear reactor is you get something that is so incredibly hot it melts through your containment vessel and causes a massive steam explosion that rips the entire reactor apart.

YOU GUYS ARE FUCKING RETARDED BEARDED HAND OF MOSES, IT'S FUCKING WATER, DO YOU KNOW WHAT FUCKING WATER IS? AND SOMETIMES GRAPHITE TOO BUT MOSTLY WATER.

WATER WATER EVERYWHERE SO LETS ALL HAVE A DRINK

Nuclear reactors do not explode even when you shut down all safeties and remove coolant.

Meltdowns are not explosions.

>>2608034
A reactor is close to critical mass, right? What exactly happens if it goes over that prevents it from exploding like a bomb?

>>2608057
>A reactor is close to critical mass, right?
Not even. Even if you introduced more fuel there is still not a high enough percentage of 235 to produce an explosion.

At the very worst you would generate far too much heat for any coolant to absorb and have a meltdown.

>>2607956

>Is coolant the only thing which prevents nuclear fission reactors from exploding like a nuclear bomb?

No

>>2608057

a reactor is critical and has _way_ more nuclear material than any bomb. ignore that other dude. nuclear bombs are built so that the inertia of the trigger (explosion) holds the device together long enough (1us) for it to release enough energy to have an explosion.

in a reactor the uranium is sitting there with nothing really to contain it after an absolutely worst case accident. if the core destroys itself and you have a uranium pile it will melt itself (and I suppose if it gets hot enough vaporize). the steam from the coolant will boil and carry off particles from the core. but the energy released will push the uranium apart before a nuclear explosion (in the bomb sense) can happen.

Theoretically, the containment building is tough enough to withstand even this. the water spray within the containment building captures any particles released from the destroyed core.

Not a NE

>>2608029
this.
i'm afraid nobody knows how nuclear reactors function.
the water is not used to slow down the reaction or cool down the reactor.
it is used as a power exchange.
graphite rods are used to control the reaction and avoid core meltdown.
25 years after the chernobyl catastrophe, it is just horrifying that nobody knows the basic principles of nuclear power reactors.

>>2608074
>implying cherynobyl's metre thick concrete walls were capabale of containing the reactor's accidentally-the-whole-thing with starved coolant supply

>>2607956
> Is coolant the only thing which prevents nuclear fission reactors from exploding like a nuclear bomb?

No. The lack of critical density prevents it.

> What elements and/or isotopes are used for nuclear fission?

Mostly U-235, although breeder reactors also use U-238 and Pu-239.

>>2608046
> Nuclear reactors do not explode even when you shut down all safeties and remove coolant.

This won't result in a *nuclear* explosion, but it might result in a chemical explosion e.g. from the production of hydrogen.

>>2608079
/g/ is full of 12 years old, don't blame them....
underage b& everywhere.

>>2608089
the thread is so dumb anon thought he was on /g/
i'm out !

>>2608079

hold on there partner.

In us reactors, the water is a moderator, and is used to drop the energy of the free neutrons to thermal energy making them more likely to be picked up by the odd 235 atom. If the water is _out_ of the core the 235 reaction stops, _but_ the half-life breakdown of the short lived isotopes can still cause the core to be damaged/destroyed, so water coolant in general should still be supplied.

I'm also pretty sure those professional NE's know how reactors work

>>2608079
http://lmgtfy.com/?q=nuclear+reactant+coolant
retards, retards everywhere

>>2608094
in my country we use pressurized heavy water as a moderator ( and graphite rods).
the water circuit is only used for thermal exchange.

>>2608094
Wow this thread has followed the exact course of one of my year 11 physics classes.

First you get the teacher asking people if they think a reactor can explode.
Then you get some people saying no but they dont know why.
Then he explains about isotopes of uranium
Then meltdowns
and then moderators and control rods.

I predict that next somebody will explain how the past nuclear accidents happened but they weren't technically "explosions"

>>2608096
you dum
water is used to produce energy, not to control the reaction.
dum, you so dum.

coolant is made to transfer heat.
If you remove it, everything will heat up and you may have problems like radioactive leakages.

It won't explode though.
The graphite rods prevent this from happening. Remove the graphite rods and if you have too much combustible, it will explode.
Safety measures don't allow this though.
In chernobyl they were doing weird experiments.

>>2608087

wat?

Chernobyl had _no_ containment structure. That was one of its many design faults.

http://en.wikipedia.org/wiki/Chernobyl_disaster

there is also a great document comparing the Canadian CANDU reactors to the russian Chernobyl reactor, demonstrating all the ways western reactors cannot fail like that.

>>2608103
So many people say this. So much wrongness...

>>2608105
[retard needed] oh wait you're already here.

Cherynobyl had plenty of insufficient containment. Your argument is worse than invalid, it's cerebal palsic incestuous offspring retarded.

>>2608105
> implying the western world has never had any near misses
three mile island
modern reactors cannot fail like that not just western ones

>>2608122

TMI's operators deliberately (and controllably) released a barely detectable level of radioactive gas into the air with no measurable effects on anyone.

Chernobyl blew physical chunks of the reactor core all over the surrounding area. In spite of the horrible accident, something like 50 people died from it (I think all operators or firefighters). It is my understanding that the effort to find long term cancer deaths has not turned up much. (people going to the doctors for check ups has resulted in fewer than normal deaths).

TMI was bad only in the political sense, because people were told before that nuclear power is 100% safe (which it is not -> nothing is 100%); the distrust created by that lie killed nuclear power in the US since then (but hopefully will come back).

>>2608150
Oh yeah that and oil companies funding Greenpeace to smear them.

>>2608150
Sure you didn't mean to say two to three hundred human deaths? not including fetal still-borns obviously.

>>2608122

TMI was nothing like Chernobyl, and even given a worst case scenario could not fail in that manner.

>>2608177

You might be right. but that number still seems shockingly low.

Lets talk about deaths of coal miners now.

>>2608177
56 is the official death toll after 15 years of investigation by the UN.

That includes long term heal problems, still births and cancer's not explained by normal regional statistics.

But did you know that more abortions were done out of fear of birth defects in the years following the CNPP incident. So basically propaganda and myth killed more than the accident itself.

>>2608194
>shockingly low
>mfw