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Two plants near Tokyo, each with multiple reactors are on the verge of meltdown after emergency backup cooling was shut down by loss of power due to flooding.  (Source: CNN)

An explosion damaged the roof of one plant, releasing radiation on Saturday.  (Source: Reuters)

The plants lie within the Tokyo metropolis. People are being evacuated from within a 20 km radius.  (Source: CNN)
Japanese nuclear disaster is cause for pause, reflection

The Sendai Earthquake struck Japan early Friday morning with unrelenting fury.  Measuring 8.9 to 9.1 Mw-megathrust the quake was among the five most severe in recorded history and the worst quake to hit Japan.  In the aftermath of this severe disaster, as the nation searches for survivors and contemplates rebuilding, an intriguing and alarming storyline has emerged -- the crisis at the Fukushima Daiichi nuclear plant.

You may recall that a few years back Japan was struck by another quake which cracked the concrete foundation of a nuclear plant, but yielded virtually no damage.

By contrast, this time the damage was far worse, creating what could legitimately be called a nuclear disaster.

I. Fukushima Daiichi - a Veteran Installation

The Tokyo district of Fukushima is home to two major nuclear power installations.  

In the north there is the Fukushima "Daini" II plant, which features four reactors -- the first of which went online in 1982.  These units produce a maximum of 4.4 GW of power and are operated by the Tokyo Electric Power Company.

To the south lies the Fukushima "Daiichi" I plant, a larger and older installation featuring six reactors, the first of which went online in 1970.  Operated by Tepco, the installation offers a combined 4.7 GW of power.  It was here that disaster struck.

II. Disaster at Fukushima Daiichi 1

While the southern installation is over four decades old, Japan has been responsible in retrofitting the plant with modern safeguards.  Among those is an automatic switch which shuts off the reactor when an earthquake struck.

The switch performed perfectly when the quake hit Friday morning, shutting of the three reactors that were active at the time.  Control rods lowered and the reaction stopped.

The next step was the cooling the power rods, composed of uranium-235, to prevent them from melting.

Cooling water was pumped over the rods for about an hour, but before the rods could be fully cooled, stopping the reaction, the pumps failed.  According to the International Atomic Energy Agency, and multinational oversight group, the failure was due to failure in the backup generators due to the tsunami flooding.

On Saturday Japanese authorities and power officials tried to use sea-water injections to complete the cooling process, but those plans were stalled when another tsunami warning arrived.

An explosion occurred inside at least one of the reactor buildings.  It is believed to be due to the build-up of pressure after the pumps failed creating hydrogen and oxygen gases, which subsequently combusted from the heat.

Malcolm Grimston, Associate Fellow for Energy, Environment and Development at London's Chatham House told CNN:

Because they lost power to the water cooling system, they needed to vent the pressure that's building up inside.My suspicion is that as the temperature inside the reactor was rising, some of the metal cans that surround the fuel may have burst and at high temperature, that fuel cladding can react with water to produce zirconium oxide and hydrogen.

That hydrogen then will be part of the gases that need to be vented. That hydrogen then mixes with the surrounding air. Hydrogen and oxygen can then recombine explosively. So it seems while the explosion wasn't directly connected with the nuclear processes, it was indirectly connected, because the hydrogen was only present because of what was going on in the reactor core.

The explosion damaged the roof of the plant and sent billows of smoke up into the air.  According to officials some radioactive material was released into the atmosphere.  Outside the plant perimeter, levels of radiation measured 8 times higher than normal.

Meanwhile reactors at the newer Fukushima II are also beginning to heat up after their own cooling systems failed.

Japanese officials have evacuated people from an expanding radius around the plants as a precaution.  Currently the evacuation zone is at almost 20 km.  They hope to try to continue cooling, but have to work around tsunami alarms from earthquake aftershocks that have continued into Saturday.  U.S. Secretary of State Hillary Clinton has announced that the U.S. is sending high-tech coolant to the plants, in and attempt to avert disaster.

III. Can a Meltdown be Avoided?

Without proper cooling, the rods will continue to heat and proceed towards meltdown, releasing clouds of radioactive gas.  The first question is thus whether meltdown can be avoided.

At the Fukushima I plant, radioactive cesium was discovered.  Cesium is in the beta decay chain tellurium -> iodine -> xenon -> cesium.  Its occurs roughly 16 hours after an unchecked uranium reaction and its presence indicates that one of the fuel rods may already have melted down.

Once one rod melts, it will be much more difficult to prevent the others from melting down as well.

According to reports, the coolant temperatures inside the reactor have exceeded 100 degrees Celsius.  If they reach 540 degrees Celsius the fuel rods will fully melt down.

The question now becomes what to do.  

According to reports by Nippon Hoso Kyokai (Japan Broadcasting Corporation), three individuals have already been exposed been the victims of radiation poisoning (likely plant workers) and that radioactivity levels at the plant have risen to 1,000 times the normal levels at the plant control room.

One option on the table is to vent the reactors, allowing them to blow off the steam and prevent a greater buildup of pressure and heat.  However, doing so could release significant levels of radioactivity into the surrounding area.

The alternative is to try last ditch cooling and hope that if the rods do melt, that the secondary containment will hold.  The release of radioactive gases from venting would pale to that if the secondary containment was breached.  Such a scenario would likely result in the modern day equivalent of Chernobyl.

Whichever course of action is selected, there's a great deal of risk of radiation exposure to those who inhabit the area in the near future.  States James Acton, international physicist, in an interview with CNN, "There's a possibility of cancer in the long term -- that's the main hazard here."

IV. Grim Lessons From the Disaster

At Three Mile Island, the U.S. learned the hard way not to put vital controls in the hands of plant operators.  Operators almost created a meltdown, when they accidentally disabled necessary cooling.  That was due to the poor quality of indicators. 

As the result, the nuclear community learned to automate shutdown processes.

Ultimately the Fukushima disaster illustrates the need for sealed backup generators.  The containment procedures in all their modern glory are useless if the backup power goes out.  And, if possible, it shows that it is desirable to build new nuclear plants farther from the sea and from fault lines (though this could cause costs to increase).

As the fight to avert meltdown plays out, the final damage won't be known for weeks to come.  But the international community is already reacting.

At this time it's vital not to overreact to this worse case scenario.  

The disaster does illustrate that nuclear fission power is far from failsafe, particularly older reactors -- even if retrofitted with modern controls.  Ultimately the international community needs to work towards fusion power, which should be much safer and cheaper.

At the same time, it's important to consider that there's a great deal of background radiation released from the burning of fossilized coal and that mining fossil fuels has led to many a great loss of life and resources as illustrated by recent coal and oil disasters.

And nuclear power is far less expensive than solar or wind power in base costs, and generally less expensive even after all the red tape that increases plant creation costs by an order of magnitude in the U.S.

There's no easy answers here.  Oil and coal power emit dangerous nitrogen and sulfur-containing gases and carbon dioxide into the ozone.  And their fuel is dangerous to obtain.  But they're cheap.  Solar and wind power are relatively safe, but they're expensive and offer inconsistent power.  Nuclear power is cheap and produces no emissions normally, but it can be a danger in the case of natural disaster or malicious attack.

It's important not to turn a blind eye to this disaster, but it's equally important not to overreact.


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RE: A bad placement decision on Japan's part....
By chrnochime on 3/13/2011 1:19:33 AM , Rating: -1
Mince words all you want. But what it boils down to is that an area contaminated by nuclear meltdown is uninhabitable for *much* longer than any other kind of power plant destroyed. That and the widespread effect on people and the wildlife is much longer lasting as well.

If you find nuclear power plant so safe, are you living near one already?


RE: A bad placement decision on Japan's part....
By Scabies on 3/13/2011 1:58:14 AM , Rating: 3
people seem to lump all nuclear events into the Cherynobyl category, what with the catastrophic explosions and uncontrollable fires and lie-till-they-die government coverup.

Nuclear reactors in "civilized" nations are designed to be self-contained in the event of a fully screwed pooch. If a meltdown occurs and the reactor is lost, its NOT going to create a ghost town of radiological quarantine. The reactor sits within a containment vessel that, unless breached by explosion or environmental damage, will hold all the fun stuff inside. (note that the explosion video is a hydrogen explosion outside the reactor building, which this article is somewhat misleading about.) Venting steam might have some of the core products in it, but once the water runs out and everything turns to magma, they just seal it and walk away. Three Mile Island, also a light water reactor (though pressurized as opposed to boiling) still has a working reactor today (TMI-1) and there's no exclusion zone.

tl;dr- until the building explodes, there really isn't any danger unless you're sitting under the steam clouds they periodically (and temporarily) vent. and the building isn't going to explode.


RE: A bad placement decision on Japan's part....
By MPE on 3/14/2011 3:17:03 PM , Rating: 2
Well we are about 1 step away from 2 buildings blowing up and releasing bad stuff.

It is fucking terrible but this is the reality. We can do the blame game later but for now, we hope Japanese and her citizens are OK.


RE: A bad placement decision on Japan's part....
By JediJeb on 3/15/2011 12:57:14 PM , Rating: 2
Even if the buildings blow up, which they have already, you still are not losing the containment on the reactor only the shell of a building that surrounds that containment unit. Except for the cooling units, everything else at the plants is working as it is supposed to when something like this happens. Had the backup generators been protected from the sea water these plants would probably not had much of a problem at all. That is one design feature that can now be improved on all other nuclear plants around the world to make them even more safe.


By MPE on 3/16/2011 9:46:50 AM , Rating: 2
As of today, there is a possibility you may need to revise your thinking.


RE: A bad placement decision on Japan's part....
By Solandri on 3/13/2011 3:23:33 AM , Rating: 5
quote:
what it boils down to is that an area contaminated by nuclear meltdown is uninhabitable for *much* longer than any other kind of power plant destroyed. That and the widespread effect on people and the wildlife is much longer lasting as well.

You're making the same mistake I just pointed out. You're looking at a specific risk instead of overall risk. Chernobyl resulted in about 336,000 people evacuated. Pollution from coal plants is estimated to kill 100,000 people each year in the U.S. 100,000 people killed each year vs 336,000 people evacuated in 65 years. Yet people shrug at the pollution billowing out of a coal plant's smokestacks, while they freak out at the mere presence of a nuclear plant. Why?

Because if there's a serious nuclear accident, the harm is concentrated in a small area and thus avoidable by declaring the region uninhabitable. When you operate a coal plant, the harm is spread all around and avoidable. Just running the things normally is much more dangerous than the worst nuclear accident in history. But because you can't avoid the air pollution there is no evacuation, no declaration of contamination, no keep out signs.

quote:
If you find nuclear power plant so safe, are you living near one already?

I have no problem living next to a nuclear plant. I am looking to buy a house near the San Onofre plant because I like the area. I hear the fishing near its warm water oulet is pretty good too.

If you're so afraid of nuclear power, here are some other risks you should take steps to minimize:
http://www.flatrock.org.nz/topics/older_and_under/...

Nuclear accident: 1 in 10,000,000 chance of dying
Scalding: 1 in 5,000,000
Food poisoning: 1 in 3,000,000
Falling out of bed: 1 in 2,000,000
Drowning in bath: 1 in 685,000
Work accident: 1 in 43,500
Car crash: 1 in 8,000

All of these are more likely to kill you than a nuclear power accident. So if you think nuclear power is too dangerous to use, then I assume you aren't doing any of these other things which are even more dangerous. You must not use hot water, you must grow/harvest/prepare all your own food, you must sleep on the ground, you must not take baths, you must not work, and you must not drive/ride in a car.

Do you do any of these things? If you do then you need to stop doing them, or you need to reassess how dangerous you think nuclear power is.


By Solandri on 3/13/2011 3:25:16 AM , Rating: 2
quote:
When you operate a coal plant, the harm is spread all around and avoidable

Obviously that should be "unavoidable".


By monitorjbl on 3/14/2011 3:12:56 PM , Rating: 2
quote:
Nuclear accident: 1 in 10,000,000 chance of dying Scalding: 1 in 5,000,000 Food poisoning: 1 in 3,000,000 Falling out of bed: 1 in 2,000,000 Drowning in bath: 1 in 685,000 Work accident: 1 in 43,500 Car crash: 1 in 8,000


Just to play devil's advocate, the chance for nuclear accidents would go up as more reactors are brought online. Not that I buy into any of the FUD about nuclear power, just pointing out that your numbers are not static.


By someguy123 on 3/13/2011 3:59:57 AM , Rating: 2
Even with meltdowns causing areas to become completely uninhabitable, and issues with radiation spreading far distances, nuclear power has still, by far, killed the least amount of people out of all power sources.

Nuclear still accounts for about 6% of total global energy. It's not like we merely stopped using nuclear after Chernobyl. I'm sure there are plenty of people who receive nuclear power and don't even realize it. Even though it's a source that generates quite a bit more power than "green" sources it still kills significantly less people than all of these sources combined.


RE: A bad placement decision on Japan's part....
By kattanna on 3/14/2011 1:37:16 PM , Rating: 1
quote:
If you find nuclear power plant so safe, are you living near one already?


do you own a cat or eat bananas?

cause if so, you are exposed daily to more radioactivity then you will find living next to a nuclear plant

knowledge.. look into it ;>)


RE: A bad placement decision on Japan's part....
By sascham on 3/14/2011 8:27:50 PM , Rating: 1
Totally missed the point. The point is that however safe the plant is when operating properly, accidents can occur no matter how many safeguards are put in place.


By JediJeb on 3/15/2011 1:00:26 PM , Rating: 2
True, but a meteorite can also fall from the sky and hit you on the head and kill you, but you don't see everyone wearing Kevlar helmets.


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