technicians were last night battling to save from meltdown nuclear reactors with failed emergency cooling systems. Only a few weeks away from the 25th anniversary of the world\’s worst nuclear accident, no one can be under any illusions of what could result if the technicians lose their battle.
Absolutely the worst that could happen, absolutely the worst possible outcome, is that the reactors end up as a puddle of cold metal at the bottom of their containment vessels.
That\’s it. The chain reaction is already shut down. All that is left is the residual heat which the water is cooling. If the water doesn\’t cool it then yes, the rods and fuel might melt. At which point they might stay liquid until they hit that 2-3 metres of reinforced concrete underneath them where they will solidify.
So the worst possible outcome is a 40 year old reactor which cannot be used again.
There cannot be a nuclear explosion, there is no possibility of a fire as at Chernobyl (because there is no graphite to catch fire). We can have, as we have had, a hydrogen explosion, but that\’s outside the reactor and outside the containment vessel. No radioactivity released as a result.
Just to give you an idea of the \”raised levels of radioactivity\” that have been reported. Between 500 and 1,000 microsieverts per hour. The top end of that range is about half what you would get if you had a CT scan.
Or, if we use the Banana Equivalent Dose (you do indeed absorb radiation from eating a banana, a pile of bananas will indeed set off a radiation detector) the mid range there is like eating 20 bananas a day for a year. One banana a day for a year is around 35 microsieverts.
So, we\’ve just had the fifth worst earthquake in the past century, the 7 th worst we have on record, a 30 foot wall of water sweeping in at 500 miles an hour and the worst part of the nuclear power system is that if you were standing right there, right at the plant, you might get the same radiation dose as a fruitarian?
And you want to use this to tell us that nuclear power is dangerous?
I\’ve got bells on the other one which will jingle if you pull it.
“The top end of that range is about half what you would get if you had a CT scan.”
Well yes, but you don’t have a CT Scan every hour of every day for a year. That sounds a bit scarier.
Does that mean that one CT Scan is approximately a banana? If so, that also suggests that people might be making a bit of a unnecessary fuss about CT scans too….
The source for this, incredibly enough, was Ritchie’s comments section yesterday:
http://morgsatlarge.wordpress.com/2011/03/13/why-i-am-not-worried-about-japans-nuclear-reactors/
Despite the provenance, well worth reading, although proved beyond the apprehension of the semi-retired accountancy community judging by his response.
Maybe we should have a whip around and buy them some kyocera zirconia knives to cut their wrists with?
I bet a year’s supply of lollipops that when the crisis is past and the Japanese get the info into the public domain we will have over 20,000 deaths and not one due to radiation exposure or even hydrogen explosions.
Every other variety of death you can imagine. But not one, not now and not even in 25 years’ time from the nuclear power plants.
Maybe I’ll be wrong by 4 or 5 people?
Somebody barking up the wrong tree? Axes to grind? Rents seeked (sic), found and needing protection.
So you can’t imagine any mechanism which would lead to anything beyond a molten reactor core inside its confinement. Well that is exactly the problem with all nuclear engineers: they only plan for the emergencies they thought about and then the thing will fail dramatically because of the things they forgot. Let me give you an example of a more spectacular outcome. One of the hydrogen blasts which seem to be inevitable destroys the pressure relief devices at the top of the pressure vessel (they have to be somewhere at the top, because you want to vent vapour, not liquid). Then the pressure vessel is on its own, happily converting water into steam until it pops. Oops, this was too much for the containment vessel, and now we are faced with Tschernobyl-like catastrophy. Unlikely? Perhaps, but there are enough other unlikely scenario’s like this for a machine which is already totally out of control which could make things much worse than you can imagine. And even if I were wrong, the general public, after seeing reactors reproducibly failing in a most spectacular way, will never buy this reassuring story anymore that nuclear power is safe. In any democratic country, political parties now in favor of nuclear power better change their opinion fast or the next election will put them out of business!
PG – no, a CT scan is 21,000 bananas (a banana is 0.1 microsieverts)
BB – it’s possible that some of the workers who’ve been injured by debris/burns from the hydrogen explosions in the outer shells of the two power stations will end up dead. I agree with you, nobody will die from radiation.
Does Daiichi-3 have the melted-uraium-puddle-catching tray? Some comments on the internet suggest it’s an older model that doesn’t have that. If not – meltdown into the water table? IANANP
Tim adds: Sorry, but that China Syndrome story is just that, a story. No, the uranium will not burn down into the water table. Try a few inches at maximum, even without the puddle catching tray. We know this from steel spills (what are called spills and skulls in the industry). There have been times when someone’s dropped 100 tonnes of molten steel onto the factory floor. Penetrates the odd centimetre before it freezes.
You might even recall what happened at 9/11. Thousands upon thousands of computers melted up in those buildings as they burned. All that solder, copper etc, flowed downwards in the heat. All ended up sitting in the basement.
Tim–if you can find a second hand copy of “The Health Hazards of NOT going Nuclear” by the late Dr Peter Beckmann, there is an interesting account of a natural nuclear reactor (a concentraition of uranium–I’m hazy on the specs-its a long time since I read the book) that started up and then went into meltdown some 1,800 million years ago in what is now the Gambia. The radioactive products (very little radioactivity after all that time of course) are still a few inches underneath the site, still there and have not “leaked” into the enviroment after 1800 million years and the land masses having traveled a good way around the Earth by plate tectonics in that time. We have long term proof of the lack of real danger in a meltdown, the worst case scenario.
There is another ready example of what hot stuff does when it hits the ground – lava flows. They run along the top rather than melt downwards.
The obvious difference between lava and steel compared to a nuclear reactor core is that the reactor core can sustain its temperature unlike the other two but it will presumably just sit there and stay hot rather than work its way downwards.
I’ve missed reading you, Tim. ;o)
So the claim the “the mid range there is like eating 20 bananas a day for a year” is similar to claiming that flying in Concorde somewhere which takes a hour is no faster than if you walked there over three weeks?
It’s a sermon to the faithful
re PG et al
““The top end of that range is about half what you would get if you had a CT scan.”
Well yes, but you don’t have a CT Scan every hour of every day for a year. That sounds a bit scarier.”
500-1000 microsieverts per hour is the rate. It’s the duration that counts. 10 seconds’ worth is trivial. Several hours’ worth is still nothing to worry about.
(1,000,000 microsieverts per hour is nasty – nausea as an immediate effect, then longer-term damage)
Bugger. Meant to say 1,000,000 musieverts in an hour, not per hour.
Mr Ecks – “if you can find a second hand copy of “The Health Hazards of NOT going Nuclear” by the late Dr Peter Beckmann, there is an interesting account of a natural nuclear reactor (a concentraition of uranium–I’m hazy on the specs-its a long time since I read the book) that started up and then went into meltdown some 1,800 million years ago in what is now the Gambia.”
Gabon. This is the Oklo Reactor.
http://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor
No containment at all. We all survived.
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So Much For Subtlety
Thanks–a long time since I read the book
“So the worst possible outcome is a 40 year old reactor which cannot be used again.”
This is not a little thing. Presumably, a portion of Japan’s power supply will be gone, and some of that portion gone permanently, after these events.
“This is not a little thing.”
Of course, neither would 700MW of windmills flattened by an earthquake/tsunami be a little thing.
http://online.wsj.com/article/SB10001424052748704893604576198421680697248.html
Also makes the point that ‘meltdown into the water table’ doesn’t happen.
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Tschernobyl-like catastrophy
I don’t know if you are trying to imply specialist knowlegde about Chernobyl by spelling it like that, but the Ukrainian word is ?????????. There is no ? at the front to give its transliteration a Ts sound.
“after seeing reactors reproducibly failing in a most spectacular way, will never buy this reassuring story anymore that nuclear power is safe.”
It doesn’t help that dickheads like your ilk keep regurgitating bullshit, to be honest.
@Techie – “Then the pressure vessel is on its own, happily converting water into steam until it pops” – that would be a seal popping (assuming ALL safety valves have failed) and a stream of steam coming out.
Unlikely to pop as in be rent asunder and blown to the wind.
So the Guardian that is putting the downer on nuclear power is the same Guardian that was keen to pile on the pressure regarding the cancellation of the loan to Sheffield Forgemasters. A loan which was for building a press to forge pressure vessels for, ermm, new nuclear reactors.
From our mutual ‘friend’, in response to someone questioning the basis for his scaremongering about nuclear power:
Tremendous.
the vast majority of people I reject utterly your rationality
Hah! Ahhhh…
Fucksake.
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bigcitylib – “This is not a little thing. Presumably, a portion of Japan’s power supply will be gone, and some of that portion gone permanently, after these events.”
They started building Unit 1 in 1967. It was originally due to shut down in 2011 anyway. But last month it got another ten year lease on life. It is not such an unexpected or big loss.
fucks sake, there’s been a third explosion – surely the activity should be dying down by now, unless there’s still a chain reaction going on, in which case who knows.
Tim: Did you see Lewis Page’s take on this at El Reg?
Tim adds: Yes, I did. Thought it very good…
So is the evacuation around the plant a waste of time?
Tim – I don’t know if they’re dropping now, but radiation levels were pretty damn high – millisieverts not microsieverts.
“Radioactivity levels increased rapidly in Japan early Tuesday as two new explosions hit reactors at the country’s earthquake-damaged Fukushima nuclear power complex, the third and fourth blasts since Saturday.
“There is no doubt that unlike in the past, the figures are the level at which human health can be affected,” said chief government spokesman Yukio Edano.
Edano said that radiation levels on Tuesday morning were 30 millisieverts between the Number 2 and Number 3 reactors, 400 millisieverts near the Number 3 and 100 millisieverts near Number 4.”
I presume that’s millisieverts per hour, which is a pretty hefty dose and would surely make working near #3 dangerous.
link
http://www.dw-world.de/dw/article/0,,14911490,00.html
johnny bonk – ” there’s been a third explosion – surely the activity should be dying down by now, unless there’s still a chain reaction going on, in which case who knows.”
No. They are taking place in new reactors each time. Not the same reactor three times. The cooling systems in all three have failed because the tsunami seems to have got salt water into the diesel fuel supply. But at different speeds. The chain reaction has long since stopped. We are talking about delayed neutrons and residual heat. Or at least we seem to be. The activity is dying down.
Fukushima I does have a lot of reactors on the one site. It used to have the most in the world I believe. Six in all. There are another four at Fukushima II which is about 10 kilometres to the south.
What might be a worry is that their coolant systems also seem to have failed.
I get the impression (via The Oil Drum) that Fukushima II (Daini) is cool. Presuming it stays that way …
http://www.tepco.co.jp/en/press/corp-com/release/11031507-e.html
I don’t know if you are trying to imply specialist knowledge about Chernobyl by spelling it like that
No, I think he is indicating that he is German. Tschernobyl appears to be the usual German spelling.
Laban – “I get the impression (via The Oil Drum) that Fukushima II (Daini) is cool.”
Yeah but it sounds like the midden hit the wind mill.
http://www.tepco.co.jp/en/press/corp-com/release/11031501-e.html
Unit 1 (shut down at 2:48pm on Mar 11th)
….
– At 5:22am, Mar 12th, the temperature of the suppression chamber exceeded 100 degrees. As the reactor pressure suppression function was lost, at 5:22am, Mar 12th, it was determined that a specific incident stipulated in article 15, clause 1 has occurred.
….
Unit 2 (shut down at 2:48pm on Mar 11th)
….
– At 5:32am, Mar 12th, the temperature of the suppression chamber exceeded 100 degrees. As the reactor pressure suppression function was lost, at 5:32am, Mar 12th, it was determined that a specific incident stipulated in article 15, clause 1 has occurred.
….
Unit 3 (shut down at 2:48pm on March 11th)
….
– We decided to prepare implementing measures to reduce the pressure of the reactor containment vessel (partial discharge of air containing radioactive materials) in order to fully secure safety. The preparation woke started at around 12:08pm, Mar 12th and finished at 12:13pm, Mar 12th.
….
Unit 4 (shut down at 2:48pm on March 11th)
….
As the reactor pressure suppression function was lost, at 6:07am, Mar 12th, it was determined that a specific incident stipulated in article 15, clause 1 has occurred.
– We decided to prepare implementing measures to reduce the pressure of the reactor containment vessel (partial discharge of air containing radioactive materials) in order to fully secure safety. The preparation woke started at around 11:44am, Mar 12th and finished at around 11:52am, Mar 12th.
….
– At approximately 11:01am, Mar 14th, an explosion followed by white smoke occurred at the reactor building of Unit 3. It was believed to be a hydrogen explosion.
– There was an increase of radiation dose at site boundary measured at the monitoring post of Fukushima Daini Nuclear Power Station.
Accordingly, at 10:07pm Mar 14th and at 12:35am Mar 15th, it was determined that that a specific incident stipulated in article 10,
clause 1 (Increase of radiation dose at site boundary) has occurred.
Article 15 Clause 1 is loss of cooling systems. You really have to feel for these guys. Two of the reactors did this:
At 0:43pm, Mar 13th, there was a signal indicating that one of the control rods may have not properly inserted. However, we confirmed that it was inserted completely by another signal.
So your reactor is powerless, heating up, the cooling has been lost, there is a risk of a major hydrogen explosion, you think you have shut the damn thing down, but your instruments are telling you that perhaps you haven’t.
I bet some of these guys are taking early retirement and they all need clean underwear.
Tim, this seems incorrect: “.. absolutely the worst possible outcome is that the reactors end up as a puddle of cold metal at the bottom of their containment vessels. That’s it. The chain reaction is already shut down. All that is left is the residual heat which the water is cooling.”
When the complete mass of the material (some of which are Mox, containing a percentage of Plutonium with a half life of 25,000 years) including the control rods melts into one lump that exceeds critical mass, the chain reaction may start again, all by itself. Of course, my knowledge stems from Internet sources and other media, so it is incomplete, but it seems clear that a complete meltdown is very bad. The control rods contain Zirconium that burns at 700°C. When it burns, it produces gases. Gases produce pressure. The rest can be observed right now in Fukushima.
It seems very important to not take any risks here. Too many have been taken already.
Tim adds: Zr does not burn at 700 oC. Sorry, but you’re way off base there. Completely wrong in fact. Similarly, a complete meltdown will not restart the chain reaction. We are always going to be dealing with the fission products, not with a live reactor.
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