nuclear fission

[azamc]

hey all, a thought iv been having:

from wiki...

'Further work by Enrico Fermi in the 1930s focused on using slow neutrons to increase the effectiveness of induced radioactivity. Experiments bombarding uranium with neutrons led Fermi to believe he had created a new, transuranic element, which he dubbed hesperium.

also

'But in 1938, German chemists Otto Hahn[32] and Fritz Strassmann, along with Austrian physicist Lise Meitner[33] and Meitner's nephew, Otto Robert Frisch,[34] conducted experiments with the products of neutron-bombarded uranium, as a means of further investigating Fermi's claims.'

my question is, if in these experiments they had used suitably enriched uranium or plutonium and fired the neutrons with the required energy, could they have unknowingly started an uncontrolled chain reaction and therefore destroyed the city?

 

[doofer]

 

[kwerk]

you need quite a big lump of it for a chain reaction.

 

[piggeh]

hey all, a thought iv been having:

from wiki...

'Further work by Enrico Fermi in the 1930s focused on using slow neutrons to increase the effectiveness of induced radioactivity. Experiments bombarding uranium with neutrons led Fermi to believe he had created a new, transuranic element, which he dubbed hesperium.

also

'But in 1938, German chemists Otto Hahn[32] and Fritz Strassmann, along with Austrian physicist Lise Meitner[33] and Meitner's nephew, Otto Robert Frisch,[34] conducted experiments with the products of neutron-bombarded uranium, as a means of further investigating Fermi's claims.'

my question is, if in these experiments they had used suitably enriched uranium or plutonium and fired the neutrons with the required energy, could they have unknowingly started an uncontrolled chain reaction and therefore destroyed the city?

The quotes say nothing about them being in a city.

 

[ChroniC]

Doesn't it depend on what type of Uranium? If it hadn't been enriched, it is difficult to cause fission.

 

[Tunney]

The quotes say nothing about them being in a city.

Their lab was a converted squash court in downtown Chicago. Quite scary!

 

[Duff-Man]

No...

Even if they were working with Uranium that was enriched to weapons-grade (which is an incredibly lengthy process involving extremely powerful centrifuges), they would still need to achieve critical mass. This isn't something you do by accident...

 

[Aod]

No...

Even if they were working with Uranium that was enriched to weapons-grade (which is an incredibly lengthy process involving extremely powerful centrifuges), they would still need to achieve critical mass. This isn't something you do by accident...

A chain reaction also requires a neutron containment vessel otherwise the neutrons escape the fissile material into the surrounding area.

 

[Tefal]

A chain reaction also requires a neutron containment vessel otherwise the neutrons escape the fissile material into the surrounding area.

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

just don't use a screwdriver to adjust your containment vessel

 

[malfunkshun]

No...

Even if they were working with Uranium that was enriched to weapons-grade (which is an incredibly lengthy process involving extremely powerful centrifuges), they would still need to achieve critical mass. This isn't something you do by accident...

One does not.....ahh forget it

 

[azamc]

critical mass is the minimum required, so if there's excess mass its OK? im not sure how big the minimum size must be for a nuclear chain reaction in uranium or plutonium, can anyone give an estimate?

plutonium doesn't need to be enriched right? it was entirely plausible that they could have used plutonium in the experiment..

also lets assume the designed the apparatus to hold the nuclear fuel to be made of steel, which wiki tells me is a reflector of neutron.

so the likeliness of a chain reaction is still possible...?

 

[Col_M]

It's actually really hard to get fissile material to go supercritical, to get a nuclear explosion large enough to destroy a city you have to get to critical mass really quickly or it'll just fizzle and blow the fissile material apart in a small explosion before a large explosion can occur.

Just bombarding fissile material that's sub-critical won't really do much apart from give off radiation and convert the material into another element.

My nuclear knowledge is a bit rusty but that should be mostly right

 

[estebanrey]

The OP is just fission for compliments

 

[D.P.]

with my minimal knowledge of nuclear physics I tend to agree with the above posters, it is actually very hard to achieve nuclear fission, otherwise every terrorist would be making their own A-bombs.

 

[Rroff]

critical mass is the minimum required, so if there's excess mass its OK? im not sure how big the minimum size must be for a nuclear chain reaction in uranium or plutonium, can anyone give an estimate?

plutonium doesn't need to be enriched right? it was entirely plausible that they could have used plutonium in the experiment..

also lets assume the designed the apparatus to hold the nuclear fuel to be made of steel, which wiki tells me is a reflector of neutron.

so the likeliness of a chain reaction is still possible...?

IIRC for enriched uranium 2 parts of ~13.5kg?

 

[drunkenmaster]

Someone should trace the OP's IP, which would probably see he is posting from some top secret government lab in Iran... which suggests where they are at in terms of making their own bomb

 

[SickAsAParrot]

According to Wikipaedia there may have been a small chain reaction during the Chernobyl disaster, but this just resulted in some of the core being splurged out of the top of the already destroyed reactor vessel.

 

[Fire_fly]

with my minimal knowledge of nuclear physics I tend to agree with the above posters, it is actually very hard to achieve nuclear fission, otherwise every terrorist would be making their own A-bombs.

The hard part is getting the required materials such as the enriched Uranium 235 to make the bomb. Getting it go bang is comparatively easy. Most Physics graduates who cover cover aspects of nuclear physics / engineering should be able to design one.

The Americans never bothered to test their designs for the Little Boy atomic bomb that they used on Hiroshima as they were so confident that it would work. The Trinity test was of a 'Fatman' implosion type bomb, not the Gun-type that was dropped on Hiroshima.

 

[LateX'Dog]

my question is, if in these experiments they had used suitably enriched uranium or plutonium and fired the neutrons with the required energy, could they have unknowingly started an uncontrolled chain reaction and therefore destroyed the city?

Well its sounds like they where in the middle of a chain reaction!