Not the nuclear thing again...

[graham]

reliable[/i]!? ffs that's just an unbelievable statement. If he meant inevitable then I apologise.

I suspect what is meant is that they are, to an extent predictable.

 

[Peter Burgess]

Clearly an eminant and respectable science journalist then... 

More credible in respect of the article under discussion than the emotive and ill-conceived rubbish some people are contributing to the debate.

 

[AndyF]

Clearly an eminant and respectable science journalist then... 

More credible in respect of the article under discussion than the emotive and ill-conceived rubbish some people are contributing to the debate.

Certainly, if you are prepared to just ignore the many factual inaccuracies in the article and read what you want to read from it. That the science and safety is all o.k. and that this is just "unlucky"... because thats what it's comfortable to believe, rather than the planners, scientists, engineers and government en masse proceeded with a really, really stupid idea. Because once you realise that, it knocks confidence in the whole system, and most people like to stay in denial when it comes to that.

So do you actually think siting these stations at the seafront in a tsunami zone is an "ok" idea....?

 

[Peter Burgess]

The vast majority of nuclear stations are sited next to the sea or a large body of water for a very good reason, Andy.

 

[owd git]

More credible in respect of the article under discussion than the emotive and ill-conceived rubbish some people are contributing to the debate.
[/quote]

 
Nuf said!
O. G.

 

[owd git]

So do you actually think siting these stations at the seafront in a tsunami zone is an "ok" idea....?
[/quote]

one side sea. other side only a seaside area or town, 
it's a win win situation. :tease:
O. G.

 

[whitelackington]

Four reactors are now in trouble at Fukushima,
including one, apparently switched off.
The Japanese government now prepared to think all is not under control!
People told not to go outdoors or drink tap water.

Germans now reconsidering their decision to keep their aging reactors
working past their design period.
Surely a government would not extend a reactors working life,
would that not be potentially dangerous?

 

[graham]

(Reuters) - Japan faced potential catastrophe on Tuesday after a quake-crippled nuclear power plant exploded and sent low levels of radiation floating towards Tokyo, prompting some people to flee the capital and others to stock up on essential supplies.

Prime Minister Naoto Kan urged people within 30 km (18 miles) of the facility north of Tokyo to remain indoors and conserve power amid the world's most serious nuclear disaster since the Chernobyl disaster in Ukraine in 1986.

As concern about the crippling economic impact of the nuclear and earthquake disasters mounted, Japanese stocks fell as much as 14 percent before ending down 9.5 percent, compounding a slide of 7.6 percent the day before. The two-day fall has wiped some $620 billion (385 billion pounds) off the market.

The French Embassy in Tokyo warned in an 1 a.m. British time advisory that a low level of radioactive wind could reach the capital -- 240 km (150 miles) south of the plant -- in about 10 hours.

Radiation levels in the city of Maebashi, 100 km (60 miles) north of Tokyo were up to 10 times normal levels, Kyodo news agency said. Only minute levels were found in the capital itself, which so far were "not a problem," city officials said.

"The possibility of further radioactive leakage is heightening," a grim-faced Kan said in an address to the nation. "We are making every effort to prevent the leak from spreading. I know that people are very worried but I would like to ask you to act calmly."

There were two explosions on Tuesday at two of the reactors at the nuclear facility after days of frantic efforts to cool them. Japan told the U.N. nuclear watchdog a spent fuel storage "pond" was on fire and radioactivity was being released "directly" into the atmosphere.

Levels of 400 millisieverts per hour had been recorded at the plant, the government said. Exposure to over 100 millisieverts a year is a level which can lead to cancer, according to the World Nuclear Association.

Japan announced a 30-km no-fly zone around the reactors.

Despite pleas for calm, residents rushed to shops in Tokyo to stock up on supplies. Don Quixote, a multi-storey, 24-hour general store in Roppongi district, sold out of radios, flashlights, candles and sleeping bags.

In a sign of regional fears about the risk of radiation, China said it was strengthening monitoring of the area and Air China said it had cancelled flights to Tokyo.

Several embassies advised staff and citizens to leave affected areas. Tourists cut short vacations and multinational companies either urged staff to leave or said they were considering plans to move outside Tokyo.

"I'm scared. I'm so scared I would rather be in the eye of a tornado," said 10-year-old Lucy Niver of Egan, Minnesota, who was on holiday in Japan. "I want to leave."

Winds over the nuclear facility were blowing slowly in a southwesterly direction that includes Tokyo but will shift westerly later on Tuesday, a weather official said.

Japanese media have became more critical of Kan's handling of the disaster and criticised the government and nuclear plant operator TEPCO for their failure to provide enough information on the incident.

 

[AndyF]

The vast majority of nuclear stations are sited next to the sea or a large body of water for a very good reason, Andy.

Yes, but that large body of water can be an inland lake like Trawsfynydd in Wlaes. There is no functional requirement to use the sea. Lots of stations inland in Europe and Russia.

I see we have had big explosion number three now, and a fire thrown in. You guy don't get the fundamantal that when things go wrong you can't put your reactor in a safe state. We are days after the event and like a Frankenstein monster they can't "switch the things off"

The people that campaigned against the siting of these stations have been proved totally right. The scientists, engineers, planners and government have been proved to be wrong and there assurances of safety to the public worthless.

It seems that the tsumani that hit japan in 1933 from an 8.3 quake swept over the very site of this station, so the history was there, but they ignored that and built it anyway. Doh!

Who was it said that those who fail to study history are doomed to repeat it?

 

[graham]

Further facts ignored by the 'clever' engineers who built these reactors where they did:

1933 Sanriku earthquake

1896 Meiji-Sanriku earthquake

From the latter reference:

At 7:30 pm on June 15, families were celebrating the return of soldiers from the Sino Japanese War and a Shinto holiday when they felt a small earthquake. There was little concern because it was so weak and there had been many small tremors in the previous few months. About 35 minutes later the Sanriku coast was struck by the first wave of the tsunami, followed by a second a few minutes later. The tsunami damage was particularly severe because it coincided with high tide. Wave heights of up to 38.2 meters (125 ft) were measured. Nearly 9,000 homes were destroyed and 22,066 deaths were recorded. Most deaths occurred in Iwate and Miyagi, although casualties were also recorded from Aomori and Hokkaido. An unusual number of the victims were found with fractured skulls and limbs either broken or missing, testifying to the power of the tsunami.

So it is wholly predictable that such events will occur with relative frequency at this precise location.

 

[whitelackington]

As Graham has shown us in 1896,
a one hundred and twenty five feet high tsunami wave would be three times higher than wot happened Friday.
I wonder why this was all forgotten about when the nuclear plants were sited.

 

[Jopo]

What if the reactors are cooled without 'meltdown', major radiation release and the situation is brought under control?

I don't know - any better than anyone else - if this will be the case but this disaster could subsequently prove to be a boost for the nuclear industry.

To have survived, albeit in a dire condition, without a major release of pollution or a melt down will be used as a plus point.

'Look folks the reactors have survived a 8.9 earthquake, a 10m tsunami and a breakdown in emergency cooling without a human or environmental disaster'

Where then could a modern reactor not be built in the UK?


It has been 4 days since the reactors automatically shut down and the activity within the cores will be reducing. My understanding is that the temperature will continue to fall and the danger of melt down likely to recede. As far as I can ascertain this is not what happened in Three Mile or Chernobyl where reaction was not shutdown and ran away as cooling failed.


Just like the rest of you I might be wrong! But of one thing I am certain. If this happened in the UK then the flow of information from our government (of any colour) and the power companies would be pitiful.

Jopo

 

[Peter Burgess]

What I know from my own experience on a tiny scale compared to the Japanese challenge, is that when you are under pressure to think fast and concentrate on a vital task, the last thing you need are distractions from people after information. I know information is important, but surely getting through the immediate problems is of paramount importance, and I just hope that those actually getting on with the job on the ground are being shielded from the world's attentions.

 

[whitelackington]

You could not make this up.
Quote BBC
"Indonesia says it will go ahead with its plans to build a nuclear reactor,
even as Japan battles to contain the radiation leak at its Fukushima plant.
Indonesian officials insist the plant,
set for Sumatra, will be safe."


I seem to recall Sumatra was recently the island which suffered a quarter of a million deaths from a tsunami.
Are governments so blinkered they can not see beyond the mantra of growth?

The Japanese government have today, yet again, increased the exclusion zone,
this time to 30k. They would have to be seriously worried that the situation is out of control to do this, they must think there is likely to be radioactive material spewing outside the plant.

 

[graham]

Four days on from the earthquake and not only is the nuclear crisis not over, it is getting worse. According to BBC Breaking on Twitter it has now been 'upgraded' to a level 6 (of 7) emergency.

 

[Alex]

As with all dangerous technology , it is only through disasters that it is made safer, just think how safe nuclear power will be after this one.

It is like airplains just think how many of them have crashed to make them as safe as they are today. It will get safer but like the plains how many deaths and disasters will this take?

 

[TheBitterEnd]

I thought this post on another forum (http://slashdot.org/pollBooth.pl) put it very well,  particularly the comment towards the end

[Nucelar power] isn't safe. It is, however, worth it. That some risk should accompany great power seems fitting.

I thought that dropping the control rods stopped the reaction almost instantaneously.

Control rods control only the primary reaction; splitting Uranium atoms by knocking them with neutrons. Fission is, however, rather messy. When an atom splits it becomes two or more different elements. Those elements are typically weird and unstable isotopes (atoms) that then spontaneously decay (regardless of the state of the control rods) again and again until they reach some (relatively) stable state. Unfortunately this takes some time and each decay event radiates energy which creates more heat. When someone says dropping the control rods stops the reaction it is implied that only the primary reaction is actually halted; the byproducts of that reaction continue to decay spontaneously.

This is why the reactor continues to produce a lot of heat immediately after scram. The amount of heat radiated after scram is sufficient produce the catastrophe we see today. Cooling must be provided to prevent this.

Either way, I would have thought that they could and would have shut down the reactors a long time ago, like, while the tsunami was on its way or even when they realized the pumps were flooded.

The reactors scrammed immediately with the earthquake. As you should now understand this isn't sufficient to safe the reactor; cooling must continue for days after scram. This is usually done with 'off-site' power supplied by another power plant. That wasn't available because of the earthquake. Backup power generation should have then provided sufficient power to cool. This equipment was incapacitated by a huge tsunami that appeared about ten minutes after the earthquake. Batteries are then expected to provide temporary power. Batteries die.

Now we have achieved the condition known in the reactor business as 'blackout.' No off-site power, no backup power. No power means no circulation and no cooling.

At this point you're stuck. The reactor is overheating and overpressure. You must release pressure to keep the reactor vessel from rupturing (because a nuclear powered radioactive steam explosion is undesirable.) Releasing pressure means releasing coolant. Coolant loss exposes fuel. Exposed fuel overheats and causes a chemical reaction that produces clouds of pure Hydrogen. The Hydrogen accumulates someplace until it burns (blows up.) The explosions do fun things like put your staff in the hospital (15 so far) and knock out the fire pumps you've rigged up to supply coolant to the reactor (4 of 5 on Monday.) Equipment failures and mistakes continue apace as usual but now you have no margin for error; when some valve fails during normal operation the operators have an array of responses. A valve failure or inadvertent actuation during a blackout means you expose the core, as happened late Monday.

Meanwhile a spent fuel pool in an otherwise safely shutdown reactor (#4) catches fire due to lack of circulation and contaminates the site with enough radiation to sterilize mammals. The damn island won't stop moving either. Several times a day a 5+ aftershock tests every piece of equipment you care about. The tsunami wiped out most of the out-buildings where you kept the tools and spare parts you might have used to fix things. Folks show up with various forms of emergency power generating equipment, but it's all the wrong voltage, phase or current capacity so it doesn't just hook up; you go into engineer mode and decipher 40 year old technical material to get it wired up. Anything you break is irreplaceable. Turn your back and generators run out of fuel.

Did your family survive the waves? They were only a few kilometers inland...sure would be nice to leave and find out. Oh, wait.

To the pole question; my opinion hasn't changed about the safety of nuclear power. It isn't safe. It is, however, worth it. That some risk should accompany great power seems fitting. Japan salvaged itself from a ruined military dictatorship steeped in mysticism and theocracy to become a rational, peaceful first world liberal democracy in part by building stuff like Fukushima Dai-ichi. The No.1 reactor has been making abundant power for 40 years; every Japanese car you've ever seen has some Fukushima Dai-ichi in it. Their drivers have a bit of culpability in all of this as well, no matter how much hatred of nuclear power they choose to indulge. If the display you're reading this on wasn't manufactured with Japanese reactor power, then it was probably South Korean reactor power. Behold the wages of your existence and then lecture me about the solar panels and windmills and other things being built with Chinese reactors.

We will learn a great deal from this incident. The last time the first world damaged nuclear fuel was 31 years ago. Perhaps the next interval will be 50. One thing is certain; we're going to find out. Even if the first world abandons nuclear the emerging world won't; hysteria doesn't rule everywhere on this Earth.

 

[dunc]

The vast majority of nuclear stations are sited next to the sea or a large body of water for a very good reason, Andy.

Yes, but that large body of water can be an inland lake like Trawsfynydd in Wlaes. There is no functional requirement to use the sea. Lots of stations inland in Europe and Russia.

Yes, but Europe and Russia both have vast tracts of reasonably 'flat' land, whereas Japan doesn't as it's mostly mountainous (and significantly more so than, say, Wales) And as for the majority of the flatter land it is densely populated and close to the sea.

 

[whitelackington]

The Germans are switching off all their old reactors.

Mind you, that's probably only until after their forthcoming election.

 

[AndyF]

Where then could a modern reactor not be built in the UK?

Its a good question. We obviously don't have many earthquakes here, and those we do have are minor...

...but how about this:-

http://en.wikipedia.org/wiki/North_Sea_flood_of_1953

So you wouldn't really want to build on the East Anglia coast...that would be reckless wouldn't it.

..oh no wait....

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

:blink: