Vagueness and the Aftermath - A sporadic diary

[Skippy]

So this is a picture of a nuclear reaction like you get in a nuclear reactor or a nuclear bomb.



The uranium nuclei are at the centre of each uranium atom. What happens is you fire a neutron in to get the whole party started (on the left in the picture). When the neutron hits the uranium nucleus it splits into two smaller nuclei (you've "split the atom"). plus some more neutrons (labelled n in the diagram).

Every time one of these atoms split, it releases some energy, which is where the heat comes from to power a power station, or where the explosion comes from in a bomb.

You get more neutrons out than you put in - so you start with 1 neutron in, but you get 3 out. These 3 neutrons can then go off and hit another uranium nucleus. For every one that hits, you get three more neutrons. Each one of the new neutrons can then make 3 more neutrons and so on.

As you can imagine it snowballs out of control which is what happens in a bomb.

To stop your power station to blowing up what you can do is have control rods. These are made of a material that act like fly paper for neutrons- they fly in, get stuck and don't leave. By adjusting the number of control rods you can keep the number of neutrons flying around down to acceptable levels, so the reaction doesn't snowball.

What happened at Chernobyl is that they took too many control rods out for a laugh. Too many neutrons meant the entire reaction got out of control and we had a disaster.

[RED-DOG]

So this is a picture of a nuclear reaction like you get in a nuclear reactor or a nuclear bomb.



The uranium nuclei are at the centre of each uranium atom. What happens is you fire a neutron in to get the whole party started (on the left in the picture). When the neutron hits the uranium nucleus it splits into two smaller nuclei (you've "split the atom"). plus some more neutrons (labelled n in the diagram).

Every time one of these atoms split, it releases some energy, which is where the heat comes from to power a power station, or where the explosion comes from in a bomb.

You get more neutrons out than you put in - so you start with 1 neutron in, but you get 3 out. These 3 neutrons can then go off and hit another uranium nucleus. For every one that hits, you get three more neutrons. Each one of the new neutrons can then make 3 more neutrons and so on.

As you can imagine it snowballs out of control which is what happens in a bomb.

To stop your power station to blowing up what you can do is have control rods. These are made of a material that act like fly paper for neutrons- they fly in, get stuck and don't leave. By adjusting the number of control rods you can keep the number of neutrons flying around down to acceptable levels, so the reaction doesn't snowball.

What happened at Chernobyl is that they took too many control rods out for a laugh. Too many neutrons meant the entire reaction got out of control and we had a disaster.

That's a terrific explanation. Thank you for taking the time.

Of course you know I now have a flood of other questions....

Why do they use uranium? Is it easier to split a uranium atom, or is the result of the split more predicable/controllable?

I assume that radiation is an unwanted by-product. Does the uranium give off radiation continuously or is it produced by the nuclear reaction?

Where does uranium come from, what are the control rods made of?

Should I be using an upper case U for uranium?

[kinboshi]

Actually the uranium in a nuclear power plant wouldn't just go 'boom' like the uranium in a nuclear bomb as the material would be blown apart before it could go critical.  You can have a meltdown, which is dangerous (see Chernobyl), but it's not the same as a nuclear bomb.  That link I posted previously mentions it a bit.

Basically, you need the lump of uranium to go supercritical, and to do that you need some clever engineering to hold the lump together long enough for the mass to go supercritical.

More here on the actual uranium required: http://en.wikipedia.org/wiki/Enriched_uranium

[kinboshi]

The reason uranium (and plutonium) are used for nuclear plants/bombs is that they are massive atoms that are 'easily' split

For example - uranium 235:

Has 92 protons (atomic number of uranium is 92, that's the number of protons).  It has 143 neutrons, and 92+143=235, which is the mass number.

Plutonium and uranium are the elements with the highest mass numbers, and therefore the biggest atoms that are found 'nautrally'.  Plutonium is far less available than uranium, and is only found in traces - instead it needs to be 'created' in nuclear reactors from other elements to make amounts that are 'useful'.

[RED-DOG]

I hope the FBI don't read blonde...

[RED-DOG]

Try this one with some copper pipe & your magnet Red....

Don't understand this at all. Is it camera trickery?

[kinboshi]

Try this one with some copper pipe & your magnet Red....

Don't understand this at all. Is it camera trickery?

Nope, it's magnetz innit.

http://www.bbc.co.uk/bang/handson/magneticcopper.shtml

[RED-DOG]

Try this one with some copper pipe & your magnet Red....

Don't understand this at all. Is it camera trickery?

Nope, it's magnetz innit.

http://www.bbc.co.uk/bang/handson/magneticcopper.shtml

So obv when you know.


The braking force in the demonstration is due to an eddy current. That's an electrical current that forms in the copper, in response to the moving magnetic field of the falling neodymium magnet.

That eddy current produces a magnetic field of its own. The two magnetic fields overlap and slow the fall of the magnet.

[atdc21]

thats bloody good eddy

[RED-DOG]

Good things that happened to me yesterday.

I found a pair of reading glasses that I though we're lost forever. (Top pocket of my overalls).

I finally stopped my chainsaw from idling too fast by removing a small leaf that had somehow got behind the gauze in the air filter where it restricted the air flow causing a semi-choking effect.
 
I now have a second grey fleck in my tache which matches the first one and prevents it from looking like a stray bogie.

[RED-DOG]

Mrs Red found this on facebook.

Even though it must have been around for years and it's narrated by one of my all time favourite presenters, I've never seen it before.

This is the Appleby Fair of my youth.

[Tractor]

Hi Red, have you heard anything about Stow, I just caught the end of the local news and it seems the land the horse fair is on has been sold for development. Just wondered if you have heard anything? I think it used to be down the Swell road, who/how do they decide where to move it?

Just found a link.

http://www.bbc.co.uk/news/uk-england-gloucestershire-24361762

[RED-DOG]

Hi Red, have you heard anything about Stow, I just caught the end of the local news and it seems the land the horse fair is on has been sold for development. Just wondered if you have heard anything? I think it used to be down the Swell road, who/how do they decide where to move it?

Just found a link.

http://www.bbc.co.uk/news/uk-england-gloucestershire-24361762

Nope. it's news to me, and I know the bloke who owns the land.

Looks like he played his cards close to his chest.

[booder]

Jack Hargreaves , proper legend.

[mondatoo]

What's your favourite place that you've ever visited ?

What's your favourite landmark you've ever visited ?

Where in the world would you like to go to most that you haven't already been to ?

Which landmark have you yet to visit that would be top of the list to do ?