Nuclear meltdown: race to save reactors in Japan

Pick a number, and that reactor is described as being near a meltdown.  The news coverage coming out of Japan is even more confused when American media deciphers it.  Hopefully hard facts come in soon…

Meltdown occurred according to Nuclear and Industrial Safety Agency

URGENT: March 12 00:00 PST: Explosion at Nuclear Facility

VIDEO of explosion at nuke plant.

Reuters Live Earthquake News Feed

Several people appear to be injured at Fukushima nuclear plant – NHK

Walls and roof of a building at site destroyed by blast – NHK via Sky News

UPDATE:  22:50 PST:  BREAKING NEWS: Pressure successfully released from Fukushima No. 1 reactor: agency

UPDATE:  21:47 PST:  Meltdown underway at Reactor #1?  http://twitter.com/#!/dicklp

Fukushima fuel cores are melting at 2000C and dropping onto steel floor. Steel melts at 1500C. Could still be brought under control, but Four other Fukushima nuke reactors are struggling with similar problem. If multiple meltdown begins, it will be uncontrollable.

Nuclear reactor coolant systems are running on batteries, and the coolant has reached the boiling point.  Extremely critical situation currently at several earthquake affected nuclear reactors. Officials are concerned that a Three Mile Island 1979 meltdown could happen here.  Reuters Link

From the LA Times:

Conditions appear to be worsening at a nuclear power plant in Fukushima Prefecture in northeastern Japan, according to local media.

The Kyodo news agency reported that the cooling system has failed at three reactors of Fukushima No. 2 nuclear power plant. The coolant water’s temperature had reached boiling temperature, the agency reported, citing the power plant’s operator, Tokyo Electric Power.

The cooling system failure at the No. 2 power plant came after officials were already troubled by the failure of the emergency cooling system at the Fukushima No. 1 plant, which officials feared could cause a meltdown.

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u.k.(us)

This seems like a good time to check sources of information.
The engineers and control operators are not wasting their time giving progress reports (I hope), the situation is being handled by people that know the system.
The best, and brightest are on the job.

vigilantfish

Japan has previously had an excellent nuclear record, barring the accident at the enrichment facilities at Toka-Murai. What a shame this is. Japan uses essentially 1960s nuclear technology, i.e. US Westinghouse reactor designs. I don’t understand completely what happened here but wonder if the automatic shut-down feature might be a poorly designed system.
The one possible bright note, once Japan pulls itself back together, is that these reactor accidents are always opportunities to better understand the causes of failure and to make corrections and improvements. It’s hard to imagine a greater test of the technology than the circumstances of these earthquakes. If the containment buildings remain intact this should be no worse than Three Mile Island. It will represent a massive economic loss and a major problem in terms of real energy shortages for Japan – but hopefully no harm will come to the people who work in and live around these plants.
My thoughts and prayers are with the people of Japan.

Claude Harvey

This is serious. Loss of coolant is the Achilles heel of all nuclear power plants. Even after a shutdown, if the residual heat cannot be rejected for several days, the danger of fuel bundle meltdown (a partial meltdown occurred at Three Mile Island), loss of pressure containment and a thermal explosion is very real. The worst case result would be a giant “dirty bomb” that could render a wide swath (depending on prevailing wind at the time) uninhabitable for many decades.
Seeing to it that such failure cannot happen under any imaginable circumstance is at the heart of all nuclear power plant safety design. Design typically includes the assumption that external electric power to the plant is lost and provides for a minimum of two redundant backup cooling systems for such an emergency. Those backup safety systems are “seismically qualified” to withstand the worse calculated earthquake possible for the geologic zone in question and protected against the worst postulated flooding.
If those backup systems failed at three of the Japanese reactors, there was by definition a defect in the design of those systems.

Sam Hall

I read that they had done a SCRAM on the Fukushima No. 1 plant and the standby generators that power the cooling system had failed. If true, they could have a partial core meltdown like 3-mile Island. Very bad PR and very expensive, but no danger.

pochas

The important thing is to keep the cores covered, even if they have to vent some steam to the outside, which is really harmless if they can keep the cores covered. If not, their reactor is toast and they will spend a couple of billion on cleanup. But regardless, the activists will set up a howl like we haven’t heard since TMI, only worse since this is Japan, the one-time nuclear target. The question is, why did those auxiliary diesel generators fail? And what does this mean for the future, assuming there is one?

Doug Allen

Hmmm. Scary for Japan which has suffered enough. Scary for all of us. I think a lot of us old conservationists/environmentalists who had opposed nuclear were “warming up” to it as the best and cheapest alternative to fossil fuels should they run out or global warming actually proved to be CAGW, which I doubt. Now, I suppose, for better or worse, we are stuck with fossil fuels, very inefficient wind, and very expensive solar. BTW, there are millions of us conservationists/environmentalists who feel the global warming zealots and green extremists have hijacked our beloved movement. Lets take it back!

Jimmy Haigh

Scary. This is why I’ve never been a big fan of nuclear…

ggm

Does anyone know if these are breader reactors or slow thermal reactors ?
From what I understand – slow reactors like these can NOT ever, under any circumstances “melt down”. They can not explode. Infact, nothing more than coolant release can happen (and that coolant is mildly radioactive, but not long lasting ??). If the coolant releases, the reactor gets a little hot, and shuts down. End of story.
“melt downs” and “dirty bomb exposions” are a myth with these sort of reactors. It`s only breader reactors (fast breaders) that have this risk, and I think it`s only the crazy Russians and Chinese who built these. If these are breader type reactors, then the Japanese are frikkin crazy people for building them in an earthquake zone. Surely the Japanse are not that crazy ??

Stas Peterson

These are Gen II reactors much like the current reactors operating in the USA for decades. To provide for extra coolant in the event of a Loss of Coolant accident, to cool the reactor after shutdown. Just like your home oven after you have baked a cake and turned the oven off, it remains hot until it cools off. This is neccessary until the reactor cools off, they have spare diesel generators to provide the electricity to drive the water pumps which pump in extra coolant, in the case that standard electricity sources are unavailable.
The 30-odd new Gen III+ designs being prepared for construction in the USA, the NRC and the reactor builders have anticipated that it is possible that regular electricty may be down, and the spare diesel generators might be unable to come online, however remote.
So the new reactor designs place the extra coolant in tanks higher than the reactor so the extra coolant can flow into the reactor with simple gravity without needing any pumps, at all. In addition the new reactors have much larger reactors vessels, that are large enough that the reactor will not need any extra coolant. Further they have been re-designed so that the coolant already there, circulates by natural thermal convection, wihtout needing any internal pumps during a shutdown.
Proving once again that the new GEN III+ reactors in the process of building in the US, are even safer than the ones that have been running safely for decades, today.

Doug Badgero
wsbriggs

I agree, waiting for more non-MSM information is probably prudent. I’m having a hard time imagining the, properly paranoid, Japanese doing a slipshod version of Peachtree.
Peachtree in my mind was much worse than TMI. It showed that some of our nuclear “engineeers” didn’t have a clue about failsafe design. When a lighted candle in a plenum can take out 5 failsafe systems, the system isn’t exactly failsafe. One of the Swiss professors in my graduate studies group was a expert witness in the examination of the accident. The stories he told… As an American I was embarrassed to hear how poorly our “Leading Engineering Firms” had designed that plant.

Les Francis

According to some Nuclear specialist sites I visited, the reactor and core is self regulating and cooling however this is regulated by a series of valves and switches which are nominally powered by D.C. The D.C. is provided by a series of back up generators and batteries.
The generators have allegedly failed (W.T.?). They were operating and have shut down?
Could be the inverters have failed and not be charging the batteries?

If ever there was an ad for thorium salt reactors, this, unfortunately is it. They can’t “melt down” because the fuel is already molten. When the power fails, the fuel cools and the reaction stops.
I just hope they can cool these suckers down enough to remove the rods.

Bob Buchanan

It seems that while they were designed to withstand earthquakes, apparently they were not designed to operate after a serious tsunami.
I don’t understand why the systems don’t automatically withdraw the fuel rods and stop the energy producing chain reaction.

Jim

The situation is basically this
The reactor would have been shutdown No more chaim reaction.
However about 10% of heat released by a reactor comes from the decay of radiocative
byproducts after original fission event. This is the energy that is the cause of the
problem. The energy release decreases rapidly. From member, after 24 hours
the energy release from these byproducts decreases by at least a factor of 10.
There should be an ECCS (Emergency Core Cooling System). This is a big
tank of water located at an elevation higher than the reactor that can be
dumped into the reactor to help keep the core from being exposed in the
case of pump failure. There has been no mention of this in any news story.
In TMI (Three Mile Island) the core was exposed. This irrevocably
damaged the reactor, but otherwise caused no harm. It was a commercial
as opposed to human disaster. One of the problems at TMI was that
the operators did not know what was going on, but I suspect that the
engineers in Japan will know what is going inside the reactor core.
The TMI accident showed that a reactor vessel and containment
vessel could withstand a loss of coolant accident that exposed the core.
If the operators vent steam from the reactor to release energy and
pressure, there may be a lot of adverse publicity, but this does
not constitute a disaster. The steam which will be radiactive and hot
will rise and disperse through the atomsphere. Compared to the
devastation caused by the Tsunami, this is a fleabite.
If the operators have access to an ECCS with water in it, then I do not
believe the worst case scenario will occur. As far as the news stories go
the frustrating thing is no mention of the ECCS which should be available
when the pumps fail.

Doug Badgero

Moderator, I think my last comment is in the spam filter.
[Posted. ~dbs]

Domenic

I read that the backup generators at the affected plants were flooded by the tsunami.
It seems strange to me that the Japanese didn’t protect their nuke plant backup generators against the worst possible tsunamis.

Phil

From: http://www.world-nuclear-news.org/RS_Battle_to_stabilise_earthquake_reactors_1203111.html

Three of Fukushima Daiichi’s six reactors were in operation when yesterday’s quake hit, at which point they shut down automatically and commenced removal of residual heat with the help of emergency diesel generators. However, these suddenly stopped about an hour later for reasons as yet unknown.
This led the plant owners Tokyo Electric Power Company (Tepco) to notify the government of a technical emergency situation, which allows officials to take additional precautionary measures.
Even now, the primary focus of work at the site remains to connect enough portable power modules to fully replace the diesels and enable the full operation of cooling systems.

To the extent that there is evaporation inside the containment vessel, some steam may need to be vented, but it is reportedly filtered before it is released, so any radiation release into the environment would be limited. After watching TV and reading other news accounts, the reporting on this story appears to be more than terrible. Let’s hope that Tepco will be able to properly manage this situation. It would appear that they are well prepared for it.

Radiation levels 1000 times normal to me is indicative that the problem at at least one plant is past the point of just being a core cooling problem. The plant is shutdown and radiation levels should be lower than normal and dropping — normal being operating at power. With rad levels that high, at least some reactor core damage may have already occurred.

Phil

From: http://nuclearstreet.com/nuclear_power_industry_news/b/nuclear_power_news/archive/2011/03/11/japanese-reactors-fine-after-7.2-magnitude-earthquake031101.aspx

As of Friday afternoon, additional backup generators were en route to the plant, and unit 1’s coolant system was running temporarily on a battery. Japanese regulators stated that pressure in the reactor had risen to 1.5 times normal levels. At 750 degrees, an engineer familiar with the BWR design told the Los Angeles Times Friday, the temperature is well below the 2,200-degree design limit for preventing cladding failure.

Cynthia Lauren Thorpe

While I promised not to comment with TOO MUCH sensitive ‘Truth’ for you ‘scientist guys’ ~ Perhaps you’d like to indulge me by going to this site and deciphering the data for me.
It regards ‘Global Weather Modification’. The results certainly ‘seem’ to be compelling – for an amateur, such as myself. I’d love to read what your insightful thoughts are.
http://www.youtube.com/user/NufffRespect#p/a/f/1/Xbp6umQT58A
The title of the youtube video is called ‘HAARP CHART FOR NEW ZEALAND’ – with any ‘luck’ – maybe in a day or two they’ll post one for Japan.
In Truth,
Cynthia Lauren Thorpe

Ed Waage

The International Atomic Energy Agency (where I worked for a year) has some info on the situation:
http://www.iaea.org/press/
The reactor is a boiling water reactor and has numerous backup systems. The situation is not a dire as the news media indicate. See also a report from the Nuclear Energy Institute:
http://www.nei.org/newsandevents/information-on-the-japanese-earthquake-and-reactors-in-that-region
The operators of the plant seem to be making some progress. The core is still covered, and the operators plan to relieve some of the pressure inside containment by venting the containment through filters which reduce the amount of radiation released. Backup power supplies are on site.

Phil

From: http://ansnuclearcafe.org/2011/03/11/media-updates-on-nuclear-power-stations-in-japan/

Japanese officials also told the International Atomic Energy Agency (IAEA) that pressure is increasing inside unit 1’s containment and they have decided to vent the containment to lower the pressure. The controlled release will be filtered to retain most radioactive substances within the containment, the IAEA said.

and

After the quake triggered a power outage, a backup generator also failed and the cooling system was unable to supply water to cool the 460-megawatt No. 1 reactor, though at least one backup cooling system is being used. The reactor core remains hot even after a shutdown.

ferdberple

“This is serious. Loss of coolant is the Achilles heel of all nuclear power plants”
I’m not sure that is true. Loss of coolant is the Achilles heel of some nuclear designs. For example, the light water civilian reactors developed from nuclear submarine technology were not really optimized to cope with loss of coolant, but rather to fit in a confined space. There are designs that are better able to handle loss of coolant.
However, the news will not make that distinction. The blame will fall on nuclear energy, not on the design faults, making it all the more difficult to built nuclear plants. A really significant failure could end to nuclear power for years to come.

rbateman

SOYLENT GREEN says:
March 11, 2011 at 7:58 pm
I hope they get it under control and pull the rods out too.
One has to wonder what was going through minds to put this plant on a 10 year extension just last month.
The design is straight out of the 1960’s.

Phil

From: http://www.world-nuclear-news.org/RS_Massive_earthquake_hits_Japan_1103111.html?je

Tohoku Electric Power Company’s Onogawa 1 suffered a fire in the non-nuclear turbine building which took eight hours to extinguish. A minor fire burned in a non-nuclear service building of Tepco’s Fukushima Daini 1 but this was extinguished within two hours.

and

JAIF issued a statement giving the status of nuclear power reactors in the effected area of Japan. This was based on various information sources, including event reports from Nisa released half an hour after the earthquake struck.
Reactor Operator Status
Onagawa 1 Tohoku Automatically shutdown
Onagawa 2 Tohoku Automatically shutdown
Onagawa 3 Tohoku Automatically shutdown
Higashidori 1 Tohoku Shut for periodic inspection
Fukushima Daiichi 1 Tepco Automatically shutdown
Fukushima Daiichi 2 Tepco Automatically shutdown
Fukushima Daiichi 3 Tepco Automatically shutdown
Fukushima Daiichi 4 Tepco Shut for periodic inspection
Fukushima Daiichi 5 Tepco Shut for periodic inspection
Fukushima Daiichi 6 Tepco Shut for periodic inspection
Fukushima Daini 1 Tepco Automatically shutdown
Fukushima Daini 2 Tepco Automatically shutdown
Fukushima Daini 3 Tepco Automatically shutdown
Fukushima Daini 4 Tepco Automatically shutdown
Tokai Japco Automatically shutdown
Hamaoka 3 Chubu Shut for periodic inspection
Hamaoka 4 Chubu In normal operation
Hamaoka 5 Chubu In normal operation
Kashiwazaki-Kariwa 1 Tepco In normal operation
Kashiwazaki-Kariwa 2 Tepco Not operating
Kashiwazaki-Kariwa 3 Tepco Not operating
Kashiwazaki-Kariwa 4 Tepco Not operating
Kashiwazaki-Kariwa 5 Tepco In normal operation
Kashiwazaki-Kariwa 6 Tepco In normal operation
Kashiwazaki-Kariwa 7 Tepco In normal operation
Tomari 1 Hokkaido In normal operation
Tomari 2 Hokkaido In normal operation
Tomari 3 Hokkaido In normal operation
In addition, the reprocessing plant at Rokkasho is being supplied by emergency diesel power generators.

crosspatch

I have been following this pretty closely.
1. Current worker exposure inside the plants is 2% above normal … or negligible.
2. Pressure buildup in containment vessels is thermal and not due to coolant leaks. Basically, the HVAC has stopped working and the air in there is getting hot which builds pressure so they are venting it. Radiation released so far is negligible.
3. Backup power has arrived at the one plant and is being installed.
4. External grid power is now available at the second plant.
So it looks like this is going to be a non-event. The problem is that these reactors are the 1970’s – 1980’s design that requires external power, HVAC, and a lot of other control systems to operate its myriad of valves, pumps, controls, etc. Modern plants don’t need all that.

crosspatch

Also, looks like the reason the diesel generators failed is because they were at ground level and flooded by the tsunami.

Tom Jones

One thing that is never mentioned in the media stories, which are everywhere, is the potential safety difference of a thorium reactor, or alternative design approaches.

Dave Worley

There are rail lines nearby. Generators have arrived and wiring is being installed.
More generators are on the way.
The media, as per standard form, is overplaying the situation for ratings.

TomRude

Let’s appreciate how Reuters is quoting their convenient sources:
“Such a blackout is “one of the most serious conditions that can affect a nuclear plant,” according to experts at the Union of Concerned Scientists, a U.S. based nuclear watchdog group.”
UCS is of course a CO2 bashing global warming group.
“(It’s) a sign that the Japanese are pulling out all the stops they can to prevent this accident from developing into a core melt and also prevent it from causing a breach of the containment (system) from the pressure that is building up inside the core because of excess heat,” said Mark Hibbs, a nuclear expert at the Carnegie Endowment for International Peace.”
The Carnegie Endowment for International Peace is a private NGO.
It’s almost as if no official atomic energy source could be found to comment here.
Reuters is of course controlled by Thomson Reuters, a company owned mostly by the wealthiest Canadians the Thomson family. Among their Foundation Trustee, Sir Crispin Tickell is global warming advocate connected to the UN UNEP and IPCC since 1991. Also the Woodbridge Company, investment arm of the Thomsons bought last year Point Carbon, providing leadership in Carbon market analysis etc…
imo this Reuters report and the choice of sources is not innocent. Should the situation deteriorate, watch for a full blown attack on nuclear energy from the green lobby.

Tucci78

The USS George Washington (CVN 73) carrier battle group of the 7th Fleet is assigned to Yokosuka as its homeport. With its propulsion provided by two Westinghouse A4W nuclear reactors, the George Washington carries not only an engineering department trained in handling damaged light water fission power systems but also primary and secondary hardware created to address loss of coolant accidents (LOCA).
Not to mention the assets of other ships in the battle group, which include electrical generation machinery which could be of great value in stabilizing the situation at Fukushima No. 2.
Has anybody been able to discover the officers and men of the George Washington task group are doing right now?

Doug Badgero

Mike,
I work at a nuke in the USA for AEP. I speak for myself not AEP. I have held both a reactor operator and senior reactor operator license. My experience is with Westinghouse PWR design and this is a GE BWR design but the basics don’t change much. As water level lowers rad levels will rise even if no fuel damage has occurred yet because water is a pretty effective radiation shield. As I said on a previous thread, the public safety issue would only occur if fuel damage occurs due to lack of heat removal AND a significant failure of containment occurred also. Your last sentence may or may not be true we can’t tell yet.
For others,
The chain reaction ended when the plant tripped during the earthquake. Heat is still generated from the decay of fission fragments. As was stated up thread, although values were overstated, this amounts to few percent power immediately after trip to a fraction of a percent an hour later decaying slowly after that. However, some form of heat removal is required for a long time or system will heat up……it’s just a matter of how fast it heats up. Lots of energy will be absorbed heating up and evaporating/boiling the water away. As I understand they also still have some capability to remove heat via a heat exchanger that would extend time to fuel damage even further. A year from know the specifics of this event will be disseminated throughout the nuke industry. I look forward to finding out the specifics.

mike g

What we may learn from this tragedy is that we just can’t engineer our society to withstand magnitude 9 earthquakes. Measly 7’s, yes, and the ocasional 8.0. But, maybe not 9.x.

Eric

Jim
I am assuming they are talking about the ECCS here:
Kakizaki, the safety agency official, said the emergency cooling system is intact and could kick in as a last line of defense. “That’s as a last resort, and we have not reached that stage yet,” he added.
http://www.foxnews.com/world/2011/03/11/japan-issues-emergency-nuke-plant-leak/

Utter NONSENSE!
Sorry, worked in Nuclear Power for 20 years. This is pure crap.
Running the cooling systems on “batteries”. B.S. Not happening.
Unable to start emergency generators? ALSO B.S., you can fly them in.
The reactors “shut down” as soon as the earthquake was above about 8.0 on the R. scale. Control rods in, reactors shut down.
Then the only “power” is decay heat.
At this time the decay heat is about 1/1000 the reactor capacity. I believe these are 1000 MW Electric, or 3,000 MW Thermal. That means decay heat is 3 megawatts.
That’s 10,000,000 BTU per hour. Divide by 1000 that means the need to vaporize 10,000 lbm per hour or 20 gallons per minute.
You could HAND PUMP 20 gallons per minute into the reactor. Dump the steam through the plant Xenon stack. It will have primarily Xenon in the output, with a little radioactive nitrogen, and a minor amount of trace radioactive elements aside from Xenon. NOT a crisis! Oh, wait, were the Japanese running with a bunch of failed fuel rods? UNLIKELY. Japanese BWR’s have been some of the cleanest in the world.
I just don’t trust the completely moronic media about this matter.
Max

After the deepwater horizon fiasco and this – let’s hope that anyone that has a battery powered fail safe, for which there is no simple backup system, is quadruple checking and testing…regularly.

PS: Radiation level’s 1000 times above “normal” is also NOT A PROBLEM.
If your background is .005 mR per hour and you vent Xenon and have a local dose of 5 MR per hour, you are 1000 times above background. If the integrated dose to any member of the public is less than about 1000 mR you are within acceptable guidelines.
That would take 200 hours, and it is UNLIKELY that any Xenon release would continue for that amount of time.

DD More

“WASHINGTON (Reuters) – The United States has transported coolant to a Japanese nuclear plant affected by a massive earthquake and will continue to assist Japan, Secretary of State Hillary Clinton said on Friday.
“We just had our Air Force assets in Japan transport some really important coolant to one of the nuclear plants,” Clinton said at a meeting of the President’s Export Council.”
http://news.yahoo.com/s/nm/20110311/pl_nm/us_japan_quake_nuclear_clinton
Some aide to the SoS let her step in it. A bit like the Russia ‘Reset’ button.
These are BWR’s (boiling-water), made by GE(1,2&6), Toshiba(3&5) and Hitachi (4). BWR’s have the reactor steam go thru the turbines, so they have extra filtering capacity.
TMI’s reactor problem, in addition to the loss of coolant, was a high pressure hydrogen bubble which if I remember right from our Power Group VP, ‘used up about 6 of the 7 safety factors for reactor pressure.’

Phil

From: http://www.science20.com/chatter_box/blog/japan_quake_media_mischief-77102

Why do some reporters like to get hold of a range of values from a scientist or engineer and then quote the number at the scariest end of the range?

and

The [Japanese Nuclear and Industrial Safety] agency says radiation levels have risen to up to about 100 times the normal figure in the central control room where the reactor’s operators are working.

Since when does up to 100 translate into 1000 times?

Source quoted: http://www3.nhk.or.jp/daily/english/12_24.html
Not that anybody would want to alarm anyone. (/sarc)

crosspatch

“I hope they get it under control and pull the rods out too.”
All of the reactors were stopped. What happened is about an hour after they shut down, the stations lost external power due to the tsunami. Without external power, they can not run the cooling systems. One site now has external power restored, the second site is operating on battery backup and will have generator power running shortly (generators are on site being installed).
It takes time to get the heat out of those reactor cores even after the reaction stops. One thing to note: NONE of the reactors have gone to their emergency cooling system. They are all still operating with the normal cooling systems. The problem at the moment is the lack of HVAC allowing the environment to heat up in the containment vessel and build pressure.
If your monitoring systems don’t have power, you can’t add makeup coolant because you can’t monitor coolant levels. They apparently lost the ability to monitor/control coolant levels when they lost power. I would expect the situation at the one plant to settle fairly soon. The other plant is a little more dicey and is still waiting that generator install.

JG

Seems to be a bunch of misinformation out there.
Rods don’t get “pulled”, the control rods are inserted to add a neutron “poison” that absorbs neutrons. This is called a “scram” or automatic shutdown. Rods inserted, no more sustainable fission reaction.
Decay heat is produced by radiocative decay of fission products. This will continue for days.
If a plant is not producing power on its own, it then needs external power to operate pumps. You have to remove heat from the source, to a sink (which is usually the ocean or big heat exchangers.)
This was an 8.9 earthquake with 7. something aftershocks.
Is anyone really surprised there wouldn’t be some damage?
My mother worked for BofA and visited the Northridge branch after the 1993 earthquake. The safety deposit boxes were propeled from the ground and hit the ceiling. And these things are not light by any stretch of the imagination.

mike g

I suspect the diesel generators tried to aspirate water when their building was over-topped by the Tsunami. Without AC power from offsite or from the DG’s, the station batteries would deplete in a few hours. This would result in a loss of all control room electronics. There is no battery-powered emergency cooling system. There is battery-powered control (solenoid valves, etc.) to control a turbine-driven pump that would inject water into the core. The steam for this would come from the reactor and exhaust into the suppression pool. This, in addition to relief valve discharge from the reactor, would result in the suppression pool (torus) water heating up and eventually reaching saturation pressure, as the news reports indicate. This would require venting to relief the pressure that would build up as the temperature builds up and as more and more water from outside the cycle is added.
Reports have continued to state the core has remained covered. If true, I suspect the high radiation levels are from damage the fuel assemblies sustained from the 8.9 magnitude shake.
I’ve been following reports from the Tepco website but it has been several hours since the last update. Unless they have brought temporary generators in, all batteries are likely dead now, meaning the turbine-driven pump would only be able to be controlled by some makeshift actuation of its governor.
Hopefully, sufficient external power to re-power the emergency core cooling systems is being provided. The TMI accident was only stopped because the operators eventually re-started the high pressure injection and put water in the core.
If water isn’t put in the core, the core will melt and eventually melt its way through the vessel and into the bottom level of containment. If this slag encounters water, it wall cool and solidify in a coolable geometry.

5 nuclear reactors have problems after power outage.
All back up failed
There is only one possible explanation
Windows Vista [sarcastic / off]

Al Gored

After reading some of the comments here, knowing how hysterical fears are about radiation and how useless the media is, and reading this here recently:
http://wattsupwiththat.com/2011/02/16/going-bananas-over-radiation/
I’m wondering how serious this leak is? No doubt the anti-nuclear power gang is going to make it seem as scary as possible.

Laurence M. Sheehan, PE

“Three Island Meltdown”, the great nuclear disaster that never occurred!!!!!
There never was a meltdown at the Three Mile Island nuclear plant. The steam pressure got large enough that a minor amount of slightly radioactive steam from the cooling system got past the emergency pressure valve. Yellow journalism at its nastiest.
And . . . they don’t build them like that, and have not for a long, long time now.
The April 1986 disaster at the Chernobyla nuclear power plant in Ukraine was the product of a flawed Soviet reactor design coupled with serious mistakes, complete meltdown, and there was no “China Syndrome”.
France gets 80% of its electrical power from nuclear power plants, sells a lot of the power generated to other nations, and there has not been even a hint of radioactive material escaping from those nuclear power plants in France that I am aware of.
Any source of power goes wrong when there is an earthquake of this magnitude. I am just hoping that the large aftershocks don’t light up a serious volcano.

mike g

@Max Hugoson
At 24 hours after shutdown the decay heat would still be around 15 megawatts. After a couple of weeks it would be around 4-5 megawatts.

rbateman

crosspatch says:
March 11, 2011 at 8:54 pm
Also, looks like the reason the diesel generators failed is because they were at ground level and flooded by the tsunami.

Drain the oil and fuel lines, bring in fresh diesel, reprime the injectors and fire up. I’m sure the plant operators are already on it.

mike g

@Max Hugoson
The hand driven pump would need to discharge into somewhere around 1000 psig.

BREAKING NEWS: Radioactive Cesium detected near Fukushima plant: nuke safety commission
http://english.kyodonews.jp/news/
BREAKING NEWS: Fukushima nuke plant might be experiencing nuclear meltdownNote