4 reactors on fire!!!
- Thread starter libby lou lou
- Start date
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ColJack said:
Unfortunately not.
Fission can be stopped instantly by dropping the control rods but it accounts for only 80% of a reactor's power. The remaining 20% comes from the radioactive decay of the fission products which are overloaded with neutrons and thus highly unstable. It's this decay that heats up the rods and it can't be turned off. You have to keep on taking the heat out until it runs down.The spent fuel rods pose a similar problem. They're spent only in the sense that they contain insufficient fissionable material to be worth using but the fission products are still breaking down. That's why they have to sit in cooling ponds for a long time.
There are quite a few things wrong with the design of the Japanese reactors. Firstly, water is a terrible choice of coolant:
1) If you lose the pressure, it boils and you lose your cooling.
2) It limits the operating temperature of the turbines which is not good for efficiency. Fossil fuel power stations can superheat their steam up to 900°C. This would create impossibly high pressures inside a water cooled reactor so they have to run at a rather pathetic 300°C.
3) Water absorbs the neutrons that are needed to sustain a fission reaction so you have to put extra fissionable material in. This is, arguably, its biggest shortcoming. If you must use water, it should at least be heavy water but, as far as I know, only Canadian reactors do this.
Water cooling was originally developed for submarines where space was at a premium. Sadly, it's now the most common choice for land based reactors because it's cheap. Moreover, the boiling water reactor, which is what the Japanese ones are, is the cheapest and nastiest of the lot. There isn't even a secondary heat exchanger in there. Radioactive steam goes directly to the turbines!
And then there's the cooling ponds for spent fuel rods. It would appear that the Japanese ones are kept just above the reactors (but outside the primary radiation shielding), ideally placed to be damaged in any reactor explosion.
There's a lot of misconception about spent fuel. I remember a survey in which a substantial fraction of the general public wouldn't go anywhere near a new fuel rod but would happily pick up a spent one.
It's not just the decaying fission products you have to worry about. The greatest danger comes from long-lived heavy elements, including plutonium, which you get when you leave uranium stewing in a neutron soup. Plutonium isn't particularly radioactive but it is highly toxic, even in microgram quantities. You really don't want it being blown into the atmosphere.So, to summarize:
1) Cheap, nasty reactor design.
2) Cooling plant not protected from tsunamis.
3) Spent fuel ponds not protected at all.
That's what you call an accident waiting to happen.
On a happier note, you might like to know that UK reactors are CO2 gas cooled. This allows for much higher operating temperatures (650°C) with no risk of boiling. Our only nuclear accident involved an air cooled reactor in which the graphite moderator caught fire, something that really should have been foreseen.
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Tokyo Electric Power Company (TEPCO) - They do not bear too much scrutiny - inscrutable as they appear.
I am betting bean counters and legislators will be ultimately to blame - But they, nor theirs, will be toiling in the danger zone - Therein lies one answer... Get 'em suited and boot 'em into the fray, they'll not be so keen to put profit before safety - if they should survive !
Overall source - (neat).
http://jpquake.wikispaces.com/Some+Good+Journalism
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[url=http://www.csmonitor.com/World/Asia-Pacific/2011/0316/Reports-Lax-oversight-greed-preceded-Japan-nuclear-crisis]The CSM[/url] said:
I am betting bean counters and legislators will be ultimately to blame - But they, nor theirs, will be toiling in the danger zone - Therein lies one answer... Get 'em suited and boot 'em into the fray, they'll not be so keen to put profit before safety - if they should survive !
Overall source - (neat).
http://jpquake.wikispaces.com/Some+Good+Journalism
-0-
The same thought the Americans gave, before using an Atom Bomb? That doesn’t seem to have stopped them from being the leaders in nuclear policing.
Blind leading the blind, comes to mind.
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J
joinerjohn
SALL, Leaders at the time of the end of WW2 gave a lot of thought to the atomic bomb. Had they not taken the decision to bomb Hiroshima, the war in the Pacific, could well have dragged on for months if not years. Don't forget who started the aggression in 1941.
Whether the USA should have carried on and subsequently bombed Nagasaki is open to debate though. Some historians feel the Japanese were ready to capitulate after Hiroshima and others think Nagasaki was a show of strength for the benefit of Russia..
I'm sure however, the use of atomic weapons did bring the war to an end and without them many more lives would have been lost, had the war continued.
Whether the USA should have carried on and subsequently bombed Nagasaki is open to debate though. Some historians feel the Japanese were ready to capitulate after Hiroshima and others think Nagasaki was a show of strength for the benefit of Russia..
I'm sure however, the use of atomic weapons did bring the war to an end and without them many more lives would have been lost, had the war continued.
Back again, glasgow and oxford affected,all hidden, don't panic the people
All hidden? It's not like there's anything to hide or cause a panic, the radiation levels are pathetic.
The Japanese energy industry are manipulative in the way they set themselves up and able to rebuff any public criticism about their conduct.
1. They are a major contributor to advertising in the media. So, any criticism by the media means a loss of revenue. Hence, the lack of transparency in the reporting of incidents.
2. They are a major contributor of jobs for the retiring government ministers etc..
My conclusion.......Tepco amongst others have got everything stitched up quite nicely. Hence their cavalier attitude to public safety. E.g. Their completely stupid and false reporting of the incident.
Tongue in cheek.....Since the Emperor has shown his displeasure this is a very serious kick up the backside for Japanese psyche. Unless they think he's a spent power as well.
1. They are a major contributor to advertising in the media. So, any criticism by the media means a loss of revenue. Hence, the lack of transparency in the reporting of incidents.
2. They are a major contributor of jobs for the retiring government ministers etc..
My conclusion.......Tepco amongst others have got everything stitched up quite nicely. Hence their cavalier attitude to public safety. E.g. Their completely stupid and false reporting of the incident.
Tongue in cheek.....Since the Emperor has shown his displeasure this is a very serious kick up the backside for Japanese psyche. Unless they think he's a spent power as well.
M
merlin50
the radiation levels were up a week ago in cornwall, but not by anything to worry about
Are we still alright to eat pasties.
H
holmslaw
No, stop eating the goddamn things and let us have some for a change!
Yes, but you probably won't need to heat them in an oven any more.
J
joinerjohn
Just don't eat any pasties that start growing 13 fingers , or an extra leg .
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