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"If There Were a Reactor Meltdown or Major Leak at Fukushima, the Radioactive Cloud Would Likely be Blown Out ... Towards the US West Coast"

George Washington's picture




 

Washington’s Blog

Agence-France Presse notes:

California
is closely monitoring efforts to contain leaks from a quake-damaged
Japanese nuclear plant, a spokesman said Saturday, as experts said
radiation could be blown out across the Pacific.

 

***

 

"At
present there is no danger to California. However we are monitoring the
situation closely in conjunction with our federal partners," Michael
Sicilia, spokesman for

 

California Department of Public Health, told
AFP.

"California does have radioactivity monitoring systems in
place for air, water and the food supply and can enhance that
monitoring if a danger exists," he added.

 

***

 

Experts have
suggested that, if there were a reactor meltdown or major leak at
Fukushima, the radioactive cloud would likely be blown out east across
the Pacific, towards the US West Coast.

 

***

 

"The wind
direction for the time being seems to point the (nuclear) pollution
towards the Pacific," said Andre-Claude Lacoste of the French Nuclear
Safety Authority, briefing journalists in Paris on the Japanese crisis.

 

***

 

Earlier
the NRC said it was "examining all available information as part of
the effort to analyze the event and understand its implications both
for Japan and the United States."

The winds could shift at any time, blowing radiation into Tokyo or other parts of Japan.

However, even if the prevailing winds remain off-shore - towards California and Washington - those American states are still a long way away. As AFP notes:

While
US nuclear experts acknowledged the seriousness of Japan's reactor
crisis, some stressed that taking steps in the United States such as
distributing iodine tablets -- which prevent iodine 131 from being
absorbed into the body -- would be "vastly premature."

 

"It's a
big ocean. These (radiation) releases are essentially going to be at
ground level," said Ken Bergeron, a physicist who has worked on nuclear
reactor accident simulation.

 

"We should not confuse it with health issues in the United States."

 

Japan is roughly 5,000 miles (8,000 kilometers) from the US West Coast.

But while the great distances make the risk of radiation exposure to Californians and Washingtonians small, it is not zero.

For example, pollution from Chinese coal factories routinely hits California. For example, Mongabay noted in 2008:

Previous
studies have documented that dust from Asia — especially from deserts
and industrial regions of China — routinely crosses the Pacific Ocean on
prevailing winds to sully the air over the western U.S.

And see this and this.

As as the Lawrence Berkeley National Laboratory wrote last December:

About
a third of the airborne lead particles recently collected at two sites
in the San Francisco Bay Area came from Asia, a finding that underscores
the far-flung impacts of air pollution and heralds a new way to learn
more about its journey across vast distances.

In a
first-of-its-kind study, scientists from the U.S. Department of Energy’s
Lawrence Berkeley National Laboratory and the California Air Resources
Board tracked variations in the amount of lead transported across the
Pacific over time.

***

It’s well known that particles and
other aerosols cover long distances through the Earth’s atmosphere. But
the details of this transport, such as that of the lead particles’
7,000-mile journey from the smokestacks of China to the west coast of
North America, are largely unknown.

 

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Sun, 03/13/2011 - 14:50 | 1046907 New_Meat
New_Meat's picture

alarmist as noted.

Sun, 03/13/2011 - 21:12 | 1047932 nmewn
nmewn's picture

I'm sure they are busily working up an angle.

May I?...you know I can't resist ;-)

You see the Stuxnet virus (unleashed on the world by the Jooos) infected a US prototype drone nuclear submarine which lodged itself in the fault line off the Japanese coast and blew up, causing the earthquake & tsunami wave thus diverting everyone's attention away from Charlie Sheen's suicidal meltdown to a real meltdown...because the media is really controlled by a three headed reptilian alien (as can be seen by their presence in a UFO surfing the tsunami wave in their ship in a recent Russian video).

I got it all in there, I think...the Canadians, Europeans & Arabs are completely in the clear on this one...no worries...LOL.

Sun, 03/13/2011 - 23:59 | 1048804 Hook Line and S...
Hook Line and Sphincter's picture

you shouldn't drink on a Sunday night nmewn.

(reptilians can be great lovers)

Mon, 03/14/2011 - 06:48 | 1049486 nmewn
nmewn's picture

LOL...beer goggles.

Sun, 03/13/2011 - 06:21 | 1046184 BigDuke6
BigDuke6's picture

Och, calm doon laddie.

Ye didnae git sae excited when ye drapped thae twa nukes oan thae japs in WW2.

-untranslated from scots.

Sun, 03/13/2011 - 23:24 | 1048601 Rich_Lather
Rich_Lather's picture

"George Washington" doing what suits him/her again: fear mongering.

 

I'm still waiting for my evacuation order from the gulf of Mexico region, George. The bags are packed...just give the word.

Mon, 03/14/2011 - 00:49 | 1049008 LeBalance
LeBalance's picture

oh?  The letter with the information that BP is still taking a long black pee (mixed more than liberally with the dispersant Corexit) in your backyard pool didn't get to you yet?

Strange, I thought most folks in the area with any common sense got that one.

oh!  I get it! You are waiting for the GOV evac notice.

Sorry mate, the BP & GOV agenda that ends in your slow poisoning and death is not in the business of sending out such warnings. Kind of defeats their goal.

Sun, 03/13/2011 - 13:34 | 1046747 rocker
rocker's picture

Easy for you to say laddie. Your on the other side of it.

Sun, 03/13/2011 - 12:40 | 1046605 chunga
chunga's picture

Which way was the wind blowing on August 6, 1945 I wonder.

Sun, 03/13/2011 - 20:04 | 1047624 Commander Cody
Commander Cody's picture

Irrelavent.  We bombed ourselves many more times than we bombed the Japanese.  Think above ground tests at the Nevada test site.

As for impact of the meltdown at the Fukushima Daichi Unit 1 reactor, it will be zero or near zero for the US.  Some radioactive particles may be transported by the prevailing winds.  But by the time it gets to the US west coast, it will be dispersed and dissipated to the extent that concentration is nil to none.  How do I know?  I work in the industry and know these things.

As for Unit 1, I pray the operators are not required to sacrifice themselves as did the brave Ukrainain fire fighters who were directed to pick up core debris that had been blown out of the reactor and throw it back into what remained of the Chernobyl Unit 4 reactor cavity.  Of the 30 or so people who were lethally exposed to radiation in that accident, they were the majority.  May God rest their souls.

As for Fukushima Daichi 1, as far as I can tell by observing pictures of the site before the explosion, during, and after, there is no more containment.  The primary containment, also called the drywell, was overpressurized to the extent that its top cover was blown off.  The drywell is an inverted lightbulb-shaped, steel-lined and reinforced concrete structure that is designed for a pressure of about 60 psig without any deleterious effects.  It can withstand about double that pressure without complete failure.  In this case, it failed catastrophically.

As a result, the secondary containment, or reactor building, had its roof blown off.  The top floor of the reactor building consists of structural steel with siding.  Yep, plain old siding.  The secondary containment is not designed to withstand large pressures.  The drywell (primary containment) is designed to contain accident effects.  You can see the structural steel still in place in the after explosion pictures.  The siding is gone.

In the slow-motion close-up of the explosion you can faintly see a circular smoke-ring-like halo emanate directly above the reactor building.  This is from the top of the drywell being blown off.  It is most likely condensed steam as it disipates rapidly.  There is no longer any containment structure remaining at this plant.  The reactor vessel and the nuclear fuel rods are the only barriers to a radiation release.

As for the fuel rods, many have been perforated and are releasing their radioactive contents.  How did I know this?  Well, the only way for the drywell to have failed is for the reactor cooling system to have failed.  If the cooling system failed, then the fuel will be impacted.  How much?  At this time, I can only guess.

Let's look at what happened.  The earthquake occurred.  Based on the robust design of Japanese nuclear plants to resist earthquake forces, it is unlikely that the ground motion damaged vital plant equipment.  However, it is apparent that the design basis did not anticipate a tsunami of such strength.  The reactor building, because of its sheer size and robust construction, most probably withstood the effects of the tsunami with minimal impact, including flooding.  Offsite power was lost to all four Fukushima Daichi units.  This was likely caused by the shutdown of most, if not all, power plants in the region.  If it was exascerbated by damage to the transmission lines and switchyard equipment at the plants from the tsunami, then even if power was available, it could not be utilized at the plants.

Emergency diesel generators are provided in the event offsite power is lost.  The diesel generators are usually housed in separate smaller buildings at ground level.  In addition, the diesel generators have small fuel tanks that are well-protected, however, they need larger, less-well-protected fuel tanks to replenish the supply to the smaller tanks.  When the small tanks run dry, the diesel stops.

It is apparent from the after tsunami photos that the large fuel tanks were damaged.  Perhaps even some of the diesel generators were also damaged.  Without AC electric power, most valves and all pumps cannot work.  Only DC (battery-backed) instruments and valves can work, but only for a limited time while the batteries have enough charge.

The GE design of Fukushima Daichi 1 has a simple and elegant natural circulation cooling system called an isolation condenser.  Natural circulation means that pumps are not needed.  Basically, the steam from the reactor vessel goes through tubes contained in a big tank full of water.  The heat from the steam is transferred to the water and the steam condenses to liquid which then returns to the reactor vessel.  The water in the tank heats up and then boils with the steam from boiling going out vents in the side of the reactor building.  This works beautifully as long as there is water in the tank.  Unfortunately, at Unit 1, with no AC power they were probably not able to replenish the water in the isolation condenser.  This is evident in the after-explosion photos showing no steam emanating from the vents.  No water, no core cooling.  The valves to operate this system, by the way, are usually DC powered and will operate until battery power is exhausted.

With no way to add water to the reactor vessel and no way to continue to remove heat, the water in the vessel heats up, turns to steam, pressure builds and needs to be relieved so that the reactor vessel is not overpressurized.  There are AC-activated relief valves that vent the reactor vessel steam to what's called a suppression pool.  The steam is condensed in the pool.  The suppression pool is directly connected to the drywell (remember that?).  If the controllable relief valves cannot be operated because power is lost, then there are manual safety valves that discharge directly into the drywell.  In either case, when steam is released from the reactor the coolant level goes down since there is no way to pump water back in without AC power.  With all this heat energy being released to the primary containment (drywell and suppression pool) there is no way to remove the energy and cool it down since no cooling pumps are operable.  As a result, the pressure in the drywell increases.

What is not evident since there is no detailed information being released is what caused the failure of the containment system.  There are only three possible scenarios, none of which are palatable.  Scenario one is that there was no way to relieve the pressure build up due to the energy release from the reactor.  I am dumbfounded to believe this was the case as all similar US plants have what is called a hardened vent pipe that can be manually opened from the outside of the reactor building for just this type of event.  It is imperative to retain containment integrity to minimize the spread of radioactive material in the event of a severe accident.

The second scenario involves the generation of large amounts of hydrogen due to the failure of the fuel rods.  In this case the vented steam contains hydrogen which then accumulates in the drywell/suppression pool until an explosive mixture develops.  An ignition source will cause the hydrogen to ignite causing an explosion as happened at TMI-1.

The third scenario, and one which is highly probable due to the lack of power, coolant and cooling capability is a catastrophic failure of the reactor vessel due to a core melt.  This would result in a instantaneous pressurization of the primary containment that it would not be able to manage.  That is what the world has seen in the explosion.  If it was caused by a reactor vessel breech or one of the other two scenarios, then there is no doubt that core damage has occurred.

I cannot see why plant operators would want to bottle up the drywell until catastrophic failure since it is the only way to minimize radioactive material release in the event of a severe accident.  I believe it was clearly out of their control.

Since the Japanese government is admitting the possibility of a core melt accident, then it is most likely already happened.  They are trying to minimize the trauma to an already traumatized population.  Luck is on their side since the winds are blowing the radioactive plume out to sea.

What no one is talking about yet is that the spent fuel pool is located on the top floor of the reactor building which is now open to the elements.  With the 25 or so ton drywell shield blocks blown out, it is likely that the pool and the fuel inside is damaged by some of this debris (25 ton pieces of reinforced concrete).  With no pumps to cool it, it will boil dry eventually if it has not already done so.  When it does, the fuel will overheat and more radioactivity will be released.  This is an extremely bad situation and one that the operators will be challenged to mitigate.  The reactor building it most likely uninhabitable due to high radiation levels.  The only way to quickly mitigate these issues is to manually add water via portable pumps and hoses.  The fact that we have reports of sea water being added is a last ditch desparate attempt to cool the reactor and/or spent fuel pool. 

I pray for the brave operators at the Fukushima Daichi plant so that they can mitigate the situation without adverse affects.

If the same loss of AC power situation exists at the other units, then they are all subject to the same result.  Let's hope that is not the case.

Sun, 03/13/2011 - 20:52 | 1047733 SWRichmond
SWRichmond's picture

The primary containment, also called the drywell, was overpressurized to the extent that its top cover was blown off.

I am curious as to what you base this statement on.  It looks to me like they'd been venting the reactor vessel into the secondary containment stucture (the observable external rectangular building) and, since there'd been core damage, free hydrogen had been released into the secondary which ignited and blew off the roof.   This is consistent with reports that water levels had fallen temporarily, which would have exposed fuel and probably led to breakdown of zirc cladding and resultant hydrogen production.  This is also consistent with reports that onsite rad levels had risen and then fallen; some shine from the core is possible under core exposure scenarios.

We don't know what's working and what isn't.  We don't know what survived the quake and what didn't.  Without adequate AC power they can't make water and so the choice to use seawater is obvious after a few days.  Trucking water in is also apparently not an option; I don't know about road access, who has power in the area and the ability to make for them and deliver it, etc.  All of the non seismically-qualified equipment is probably caput, especially the stuff that was running when the quake hit.

You can see them following procedures here (this is for Daini but similar statements can be seen elsewhere):

- 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.

http://www.tepco.co.jp/en/press/corp-com/release/11031311-e.html

I'm a PWR guy so my knowledge of BWRs is a bit rusty. It seems they've lost their ultimate heat sink and have been feeding the reactor and condensing the steam into the suppression pool. After awhile, the pool is at 100C (boiling) and so they can't do that anymore. Where to put the heat? Vent it to atmosphere. Also, now they need to vent the containment so that it doesn't overpressure. If there has been fuel damage, there will be hydrogen vented to the reactor building.
Sun, 03/13/2011 - 20:14 | 1047647 akak
akak's picture

Outstandingly informative post CC --- thank you!

Sun, 03/13/2011 - 20:23 | 1047677 Commander Cody
Commander Cody's picture

You are welcome.  I have been very upset by the happenings at Fukushima Daichi.  While some folks criticize the industry, and at times for good reason, the fact is that almost all plants are well-designed, constructed and operated.  The Japanese had an opportunity to assess the possibility of such an occurrence based on the Indian Ocean earthquake and tsunami, and the last major quake a few years back that impacted Kashiwasaki Kariwa plant.  They failed to put two plus two together and have paid the price.

Sun, 03/13/2011 - 20:29 | 1047693 akak
akak's picture

I am sure that I am not nearly the first person to think this, but one has to wonder just what Japanese Einstein decided to build a nuclear power plant at sea level, on the coast, of a nation historically and famously known to be vulnerable to tsunamis as well.

Mon, 03/14/2011 - 00:20 | 1048043 New World Chaos
New World Chaos's picture

This was undoubtably a cost-saving decision.  It helps to build a nuclear power plant next to a large, cold body of water to use as a heat sink.  It also helps to keep it close to the level of that body of water, so as to minimize pumping costs.  Still, they could have put the power plant on a hill and put the heat exchanger in a bunker at the bottom of the hill near the edge of the sea, with everything connected via tsunami-proof underground pipes.  They also could have put their backup generators on giant stilts.

Sun, 03/13/2011 - 09:29 | 1046325 falak pema
falak pema's picture

It's wonderful what a glass of Glenfiddich on the rocks can do to a guy wearing a kilt and scraping the ground with his niblick to chase the moles from his eighteen holes.

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