Nuclear Meltdown

  Graham. 23:28 14 Mar 2011

As I understand it, this is when the chain reaction can no longer be controlled and the fuel melts down into the ground and just keeps going down.

Will it only stop when it reaches the Earth's core?

  Uboat 00:18 15 Mar 2011

ive been keeping an eye on the media & the japanese goverment & to be totaly honest i'm NOT impressed! with them, they have denied the world the truth over what is REALY happening over there & they have now made themselves look fools!
for days ive wondered what is "realy" happening with the nuclear power station???
its all been smothered & kept it just about pride...

  Forum Editor 00:43 15 Mar 2011

is when the cooling system fails, and reactor fuel rods overheat to such a degree that they begin to melt.

Initially the molten metal pools on the floor of the reactor chamber, but if that fails the melt will fall through into the outer containment chamber. This chamber is deigned to withstand an event like that, and all being well the metal will stay there.

If something goes wrong the metal could possibly melt through the floor of the containment chamber and reach the ground below. Molten metal would come into contact with groundwater and cause a massive steam explosion. Apart from scattering radioactive fragments into the surrounding area there's the danger of radioactive contamination of groundwater. It's a very serious situation indeed.

"Will it only stop when it reaches the Earth's core?"

There's absolutely no chance of that happening. The molten metal would cool and solidify quite soon after it came into contact with the ground. The danger is from radioactivity.

  Forum Editor 00:51 15 Mar 2011

How do you know that?

I very much doubt that the people at the power plant are keeping anything secret, they're far too busy trying to avert a disaster in top of a disaster.

Try to understand what it must be like for the Japanese authorities in the face of the cataclysmic events of the past week. The one thing the situation doesn't need right now is a lot of misinformation and panic. I imagine the very last thing on their minds is worrying about holding press conferences so we can all be told every detail of what's going on.

Neither you, me or the bloke at the pub have any right to expect the Japanese government to tell us anything - they're busy trying to stop a few thousand more people from dying needlessly. Complaining that "they have denied the world the truth over what is REALY happening over there" is ridiculous in the circumstances, especially as you have no basis for making such an allegation.

  Chegs ®™ 03:06 15 Mar 2011

Besides FE's comments,consider that whatever the country they aren't going to reveal the workings of an atomic power station.

  Noldi 06:35 15 Mar 2011

What I understand is they had 3 safety procedures and they have all failed one after the other.

When the quake struck they used first procedure and that was to insert rods to stop the nuclear reaction and to pump water through the chamber to cool the rods from 1200 to around 200 deg. Second problem was the power to the pumps failed and the backup Diesel pumps kicked in and all was fine. After that the Tsunami stuck and at this time the Diesel pumps failed so the next option was to flood the chamber with sea water and cool the steam to return into the chamber as coolant. I think the problem is they have a leak and they are loosing fluid and that is very worrying.


  carver 08:12 15 Mar 2011

As far as I can see they have been trying to stop a meltdown and been doing everything they can do stop it.

This is not some thing that you can practise, you can read all the books and manuals you want but this is the real thing, they have tried to control it and now are asking for help from the IAEA, so Uboat what have they been hiding?

I don't suppose there are many Experts who have had to deal with this scenario first hand, I suppose the experts in Japan who have been trying to stop this are the ones who were injured in the explosions.

  morddwyd 08:43 15 Mar 2011

As you say, it's been over hyped.

For days the media have been talking about a serious problem.

Now it looks as though there really may be a serious problem, they don't know what to frighten people with next.

The time to start worrying is if it starts to look like another Chernobyl, and at the moment there is little chance of that.

  interzone55 09:22 15 Mar 2011

There's a couple of very interesting pieces about this on The Register at the moment.

The power stations reacted exactly as they should in the case of an earthquake, they shut down and the back-up diesel generators kicked in to keep the cooling pumps in action.
Unfortunately the tsunami then struck and wiped out the first & second backup diesel generators. At this point the battery backups kicked in - but these only have a shortish life, designed as they are to cover between the first & second backup generators. So they soon expired.

The rest of the tale is complicated, but events largely have gone to plan - hydrogen built up, so was vented into the rest of the building, when this built up too much it was allowed to explode as damage to the outer building was less bad than damage to the containment chambers or venting radioactive gases into the atmosphere.

Read more here - click here & click here

  Armchair 10:03 15 Mar 2011

"Neither you, me or the bloke at the pub have any right to expect the Japanese government to tell us anything"

That's also my take on the situation. Got enough problems of my own without worrying about people on the other side of the world.

  Mr Mistoffelees 10:04 15 Mar 2011

Read this click here from the BBC for a more sensible view of what is happening in Fukushima.

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