Earthquake/Tsunami Thread - FG Members Check In.

Wikipedia is pretty informative on the Chernobyl disaster.

The main issues with that reactor included control rods that, upon insertion into the core, led to a power spike before lowering the power output, which is their task. Since all the rods were inserted at the same time in Chernobyl, they produced a massive power spike which initiated the disaster. Then there was the issue of the lacking containment building - Fukushima has one, albeit it seems to be damaged. After the explosions, the graphite used to moderate the reactor burned for days and the heat and gases from those fires elevated radioactive dust into the atmosphere, which caused the wide spread of contamination. AFAIK, there is no graphite inside the Fukushima plant.
 
Also surprisingly says Chernobyl was only decommisioned in 2000. Fire broke out in reactor 2 in 91, then reactor 3 finally shut down in 99.

hansvonaxion;1613436[/QUOTE said:
Where are those images from?
 
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You seem to know something about nuclear plants and radiation, so elaborate or explain if you can: I read experts saying this is different type of plant to Chernobyl and that chances for a huge explosion sending radioactive particles flying all over the place would be pretty slim. Of course there's still the matter of the exposed core if it melts down.

Correct. While not going into long boring details about it, there were two elements to the Chernobyl disaster that made it so bad - seriously flawed design and stupid operators. The Wikipedia article goes into it quite exhaustively and does explain it. Basically the design was such that when you attempted to shut it down or reduce power, power output (and heat) would actually increase for a while. Unfortunately, the operators didn't know this, so when they tried to shut it down after a stupid and failed experiment that they'd run with the reactor, wherein they took the few safeties the thing had offline, the thing looked like it was running away. They did a stop-start-stop-start sort of thing because they were trying to figure out why it was reacting like that... unfortunately, nobody at the plant realized that every time you tried to 'stop' the reactor, more coolant was displaced.... Eventually someone hit the panic kill button when the thing was at full output. Unfortunately, like prior attempts, this displaced coolant, the already redlined core spiked and overheated and the thing melted down. It then went critical and the result was (effectively, though this is not exactly technically correct) a very, very small nuclear explosion which ripped through the plant - and threw debris over a huge radius.

While it is faintly possible for a Western-design reactor to have such an explosion (and you can even have them on scales down close to hand-grenade energy levels), you won't have the debris scattered over several hundred miles like Chernobyl because unlike the Soviet RBMK design, Western reactors all have a massive containment vessel or shield placed around them. Even if you do have a 'nuclear excursion' critical event, it shouldn't breach the containment vessel. Western reactors also do not operate with anywhere near the quantity or density of radioactives so any such explosion would be considerably smaller (and therefore within the capabilities of the containment vessel to retain). In fact, the Soviet RBMK reactor design could best be classified as "nuclear power generation through brute force and mass with little concern for user safety" like many Russian designs, and it operated with enormous amounts of radioactives.

Mostly the failure mode for Western reactor designs is going to be meltdown, which while not good isn't going to produce The China Syndrome or Chernobyl.

Western reactor designs also (and I'm being very general here) include multiple passive safeties that are intended to operate whether or not the operator is doing their job, and that cannot be taken offline. Things that rely on floats and such and not complex electromechanicals that are prone to failure. You also don't get to run experiments in Western commercial power generation reactors - we use research reactors for that. On top of that, Western reactors are designed such that in a worst case scenario, if everything fails, additional systems try to buy time for the populace to get the hell away from the thing, something else the RBMKs didn't have or even consider.

Unfortunately, while this reactor is a Western design, it dates back to 1971 and it doesn't have nearly the insanely multiply redundant safety systems that later designs do, especially post-TMI and -Chernobyl. I live near a reactor complex and this sort of failure can't happen to it - but they're 20 years newer and are the US Navy-style military-type PWR design. This Japanese one is the simpler but more failure prone BWR type of which the Chernobyl RBMK was a member (but without the safeties and with far more radioactives than we'd use in the West - because all that costs money that they didn't have and they didn't see the need). You could never get the Soviet RBMK design approved in the West, it was just too blatantly dangerous.

Edit: And yes, the resulting graphite fire also spread radioactive particles through the area - though, IIRC, it was the initial explosion that did most of the local spreading (it went upwind, the graphite fire crap went downwind and into the stratosphere). Western reactors like Fukushima do not use graphite rods as moderators precisely because of their flammability under those conditions. We use boron, halfnium (my personal favorite, and IMHO why the US Navy has never had a rod fail, ever) and silver-indium-cadmium - none of which are flammable in conditions obtaining in a reactor.
 
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For information, within the last hour or so, a BBC TV News team heading for the facility at Fukushima, got turned back by a Police road block 60 kilometers from the site. Probably just a precaution in case they need to extend the exclusion zone.

(Note: The Police were turning back everyone else as well, not just the media.)
 
For information, within the last hour or so, a BBC TV News team heading for the facility at Fukushima, got turned back by a Police road block 60 kilometers from the site. Probably just a precaution in case they need to extend the exclusion zone.

(Note: The Police were turning back everyone else as well, not just the media.)

Yes - because what you need is MORE potential casualties heading into an area where an reactor could breach containment. I would agree with the Japanese authorities - you need to keep people out of the area overall to prevent them from adding to the body count in case the worst happens.

I'm sure they don't want people flooding into the area, it makes sense. Also, need to keep roads clear for emergency vehicles and possible future evac.

Yeah, especially if they have plans to implement contraflow on the highways for maximum vehicle traffic away from the area. Texas did something similar when we got millions of people away from the coast ahead of Hurricane Ike - the press complained as well.

But because of those policies we only had 103 deaths. Screw the press.
 
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Lots of info

Cheers. With the amount of bullshit reporting going on it's hard to tell whether the experts quoted are actual experts or "experts" picked from the street.



Was this posted yet? Looks like the news were on TV pretty swiftly as well.

[video=youtube;871E8_DJ-rw]http://www.youtube.com/watch?v=871E8_DJ-rw[/video]
 

I was speaking to a friend of mine about that earlier this evening. The energy levels involved are literally on an astronomical scale. As in, drop-a-very-large-rock-from-orbit scale.

Cheers. With the amount of bullshit reporting going on it's hard to tell whether the experts quoted are actual experts or "experts" picked from the street.

To present the other side of this - nobody, least of all me, is saying that a Western reactor is totally, 100%, utterly safe. Or that there will never be anyone outside the reactor complex injured by an accident, or that bad things won't happen. But it's one of the safer things designed by Man and great thought went into the failure modes. And you won't get a Chernobyl event with one.

Prior to this, Three Mile Island was the worst Western nuclear disaster. Number of people outside the reactor complex proven to be killed by the reactor meltdown: Zero. You read that right - ZERO. Nobody has ever been able to prove a single offsite death, and people have been looking for decades now.

TMI didn't even change the cancer, birth defects or death statistics in the area. Due to the prevalence of Radon gas and the general high background count of the area, all of those were already elevated long before the reactor was constructed - TMI didn't even move the needle.

Like I've said elsewhere - I have a nuclear reactor for a not-so-distant neighbor and while there is an element of risk, I would much rather have one of those nearby than a coal-fired plant or a natural gas one.
 
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according to german tagesschau news, fukushima meltdown has been confirmed.

(sorry if this has been in here before, somehow i lost any overview in here)
 
I was speaking to a friend of mine about that earlier this evening. The energy levels involved are literally on an astronomical scale. As in, drop-a-very-large-rock-from-orbit scale.

The atomic bomb registers at a 5.0 on the richter scale. This earthquake was equivalent to ~705,000 atomic bombs going off simultaneously in terms of energy.

I'm somewhat relieved that Japan has quite possibly the best retrofitting of its buildings in its major cities and whatnot, but it still doesn't take your attention away from the lives unfortunately lost in the countryside and rural coastline areas.
 
So apparently those on the West Coast need not be worried about a quake on the magnitude of this one, although you'll still see massive infrastructure damage.

http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2011/03/11/MN961I9FJ8.DTL

California unlikely to see a quake like Japan's

(03-11) 17:34 PST SAN FRANCISCO -- Earthquakes the size of the one that struck Japan on Friday are highly unlikely ever to hit the California coast, but smaller quakes along the San Andreas or Hayward faults could prove just as devastating, experts say.

No temblor greater than a magnitude 8 is ever likely in California, say scientists at the U.S. Geological Survey in Menlo Park.

"But the next big quake in the Bay Area on either the San Andreas or the Hayward will be a $200 billion disaster," warned Thomas M. Brocher, who leads the USGS region's efforts at preparedness for the next Big One.

The San Andreas, which runs for some 810 miles from Cape Mendocino to the Salton Sea, is the state's most dangerous fault because the magnitude of any earthquake is primarily dependent on the length of a fault's rupture zone, explained Ross Stein, a geophysicist at the USGS.

But the north and south segments of the fault are separated by a central stretch of about 100 miles between Hollister and Parkfield in Monterey County, and it is that section that should prevent any earthquake as powerful as the one that struck Japan on Friday. In the Hollister-Parkfield segment, the brittle rock of the Earth's upper crust "is lubricated like talcum powder," Stein said. The result, he said, is a steady creeping motion that acts to relieve the constant buildup of stress within the fault that otherwise could trigger a major temblor along the entire length of the fault.

The '06 quake

The Great San Francisco quake of 1906, for example, did not rupture the entire San Andreas fault, but ripped the northern segment for about 400 miles between Cape Mendocino and San Luis Obispo. That quake is now scored at magnitude 7.8, which is about as large a quake as we're ever going to see around here, Brocher said.

The creeping segment between Hollister and Parkfield is a "very real barrier" that prevents a rupture of the ground along the entire length of the San Andreas, said geologist David Schwartz, a member of an expert panel on seismic hazards that concluded recently there is a 62 percent probability of a "major damaging earthquake" with a magnitude greater than 6.7 striking the Bay Area before 2032.

But a temblor's magnitude has little to do with damage and destruction caused by any earthquake. The depth at which a quake originates can be a more important cause, Schwartz said.

Ground matters

The nature of the ground where a fault lies can also be a major cause of death and damage. Last month, for example, a magnitude 6.3 quake hit the New Zealand city of Christchurch, which lies on a river delta, where the ground is highly unstable. As a result, much of the earthquake damage was caused when the earth turned to liquid under the shaking - called liquefaction - similar to what occurred during the Loma Prieta quake of 1989 when San Francisco's Marina district was heavily damaged, Brocher noted.

'Strike-slip' events

Most of California's earthquakes - including the 1906 quake - are known as "strike-slip" events, meaning one side of the fault moves sideways against the other as the fault itself snaps abruptly to relieve the stress building up deep inside it.

The entire San Andreas marks the grinding of two great slabs of the Earth's crust past each other: The vast Pacific Plate on the west side of the fault is actually moving slowly northward past the North American plate on the east, and that's where the stress builds.

But in California's far northern region where the San Andreas appears to end on the coast of Humboldt county, it actually turns due west beneath the Pacific into a region where another slab of the Earth, known as the Juan de Fuca Plate, is diving ponderously beneath the coast of North America.

Subduction zone dangerous

This is the Cascadia Subduction Zone, and here the danger of truly large quakes is much greater than anywhere in California, Schwartz said. Many quakes there are caused when one side of a fault thrusts upward or downward against the other, and some of them can be huge.

Old quake discovered

Brian Atwater of the USGS in Seattle, for example, discovered evidence of an earthquake hundreds of years ago that struck the Cascadia region and ruptured along a fault 600 miles long at a depth of 40 to 70 miles.

He found the evidence in layers of rotting vegetation and the growth rings of downed trees, and by using radiocarbon dating technology, Atwater estimated the date between 1700 and 1730.

Then, in ancient Japanese records of coastal damage, Atwater found that a huge tsunami had wiped out many villages there. By calculating the speed of the tsunami across the Pacific, Atwater and his colleagues determined that a "megathrust" quake must have struck at almost exactly 9 p.m. on January 26, 1700, with an estimated magnitude of 9.

That date and time are now on the record books.

By comparison, Friday's 8.9 quake that hit Japan and caused a devastating tsunami, ruptured a fault 186 miles long and 15 miles beneath the ocean floor, 80 miles off the nation's eastern coast.

Combined with the constant preparation for disasters like wildfires as well as a massive military presence, I think the majority of CA or Oregon won't experience the level of human chaos and lack of response seen in Katrina, at least if you stay away from the major metropolitan areas. Nevertheless I found via Lifehacker a site that purportedly helps you prepare for such a disaster and building a 72-hour survival kit. http://72hours.org/
 
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Correct. While not going into long boring details about it, there were two elements to the Chernobyl disaster that made it so bad - seriously flawed design and stupid operators. The Wikipedia article goes into it quite exhaustively and does explain it. Basically the design was such that when you attempted to shut it down or reduce power, power output (and heat) would actually increase for a while. Unfortunately, the operators didn't know this, so when they tried to shut it down after a stupid and failed experiment that they'd run with the reactor, wherein they took the few safeties the thing had offline, the thing looked like it was running away. They did a stop-start-stop-start sort of thing because they were trying to figure out why it was reacting like that... unfortunately, nobody at the plant realized that every time you tried to 'stop' the reactor, more coolant was displaced.... Eventually someone hit the panic kill button when the thing was at full output. Unfortunately, like prior attempts, this displaced coolant, the already redlined core spiked and overheated and the thing melted down. It then went critical and the result was (effectively, though this is not exactly technically correct) a very, very small nuclear explosion which ripped through the plant - and threw debris over a huge radius.

While it is faintly possible for a Western-design reactor to have such an explosion (and you can even have them on scales down close to hand-grenade energy levels), you won't have the debris scattered over several hundred miles like Chernobyl because unlike the Soviet RBMK design, Western reactors all have a massive containment vessel or shield placed around them. Even if you do have a 'nuclear excursion' critical event, it shouldn't breach the containment vessel. Western reactors also do not operate with anywhere near the quantity or density of radioactives so any such explosion would be considerably smaller (and therefore within the capabilities of the containment vessel to retain). In fact, the Soviet RBMK reactor design could best be classified as "nuclear power generation through brute force and mass with little concern for user safety" like many Russian designs, and it operated with enormous amounts of radioactives.

Mostly the failure mode for Western reactor designs is going to be meltdown, which while not good isn't going to produce The China Syndrome or Chernobyl.

Western reactor designs also (and I'm being very general here) include multiple passive safeties that are intended to operate whether or not the operator is doing their job, and that cannot be taken offline. Things that rely on floats and such and not complex electromechanicals that are prone to failure. You also don't get to run experiments in Western commercial power generation reactors - we use research reactors for that. On top of that, Western reactors are designed such that in a worst case scenario, if everything fails, additional systems try to buy time for the populace to get the hell away from the thing, something else the RBMKs didn't have or even consider.

Unfortunately, while this reactor is a Western design, it dates back to 1971 and it doesn't have nearly the insanely multiply redundant safety systems that later designs do, especially post-TMI and -Chernobyl. I live near a reactor complex and this sort of failure can't happen to it - but they're 20 years newer and are the US Navy-style military-type PWR design. This Japanese one is the simpler but more failure prone BWR type of which the Chernobyl RBMK was a member (but without the safeties and with far more radioactives than we'd use in the West - because all that costs money that they didn't have and they didn't see the need). You could never get the Soviet RBMK design approved in the West, it was just too blatantly dangerous.

Edit: And yes, the resulting graphite fire also spread radioactive particles through the area - though, IIRC, it was the initial explosion that did most of the local spreading (it went upwind, the graphite fire crap went downwind and into the stratosphere). Western reactors like Fukushima do not use graphite rods as moderators precisely because of their flammability under those conditions. We use boron, halfnium (my personal favorite, and IMHO why the US Navy has never had a rod fail, ever) and silver-indium-cadmium - none of which are flammable in conditions obtaining in a reactor.

So what you wanna say is: Western reactors are safe, unless some natural disaster hits them. Something that can't happen at sea that way, btw., except you are in a war of course, and a nuclear-driven ship is destroyed.

according to german tagesschau news, fukushima meltdown has been confirmed.

(sorry if this has been in here before, somehow i lost any overview in here)

Yep, SPIEGEL Online confirms it. Looks like the meltdown is in process.
 
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Edano says Japan will allow Fukushima plant owner Tepco to fill the reactor with sea water to cool it down, and that there was an explosion at the plant, but not at the reactor container.
 
So what you wanna say is: Western reactors are safe, unless some natural disaster hits them. Something that can't happen at sea that way, btw., except you are in a war of course, and a nuclear-driven ship is destroyed.

Nuclear reactors on ships at sea can be subjected to more Gs of acceleration and impact than even the Fukushima plant endured, and they have to stay online and operational, they don't have the option to shut down any time the sea gets rough.

Natural disasters have hit Western reactors before. San Onofre Nuclear Generating Station has been hit by many, many earthquakes over the years including the 89 Loma Prieta quake, and the later Northridge quake, which while numerically low on the Richter scale had the highest ground acceleration ever recorded in urban North America, approaching a full 2G. Likewise the Diablo Canyon plant. None of them have had a breach.

That said, most plants in the US are the military-type PWR reactors, which are inherently more stable than the BWR types. Europe and Japan seem to favor the BWR types, mostly because they're cheaper. PWRs cost a lot more to make.


Yep, SPIEGEL Online confirms it. Looks like the meltdown is in process.

Not good, but not end of the world, either - so long as the containment vessel is intact. (What blew up and is visibly missing is the shell around the unit, not the unit itself, though we don't know the status of the vessel.)

Edano says Japan will allow Fukushima plant owner Tepco to fill the reactor with sea water to cool it down, and that there was an explosion at the plant, but not at the reactor container.

That sounds like the containment vessel is intact and the 'venting hydrogen igniting' theory of what happened is most likely. If it was a hydrogen explosion, the containment vessel (if properly made and maintained) should shrug it off as it is a tiny fraction of the energy it is designed to withstand.

You can detonate a tactical nuclear weapon on top of what we use here as a containment vessel for commercial reactors and it should still retain containment. It's not going to be happy about it, but it should retain structural integrity.
 
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Not good, but not end of the world, either - so long as the containment vessel is intact. (What blew up and is visibly missing is the shell around the unit, not the unit itself, though we don't know the status of the vessel.)

A Japanese poster on another forum says (from a government press conference) that the outer wall of the building was blown off by a hydrogen explosion, but that the reactor containment itself is not breached.
 
Yeah I heard it was between the the reactor and the outer building.

They reported 1015millisievert (1.015sievert) at the site, but the level apparently fell after the explosion. I didn't know what that meant but wiki says...

For acute (that is, received in a relatively short time, up to about one hour) full body equivalent dose, 1 Sv causes nausea...
 
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