Hell No, We Don't Glow!

[firebird77clone]

Hey y'all.

 

My dad is a retired nuclear engineer, whom was heavily involved in researching the three mile island nuclear power plant mishap, and he has written a nice article on Japan's situation. It's a good read.

 

 

 

Anatomy of a meltdown...or why Jane Fonda is a drooling idiot.

.by Darwin Grigg

 

 

As advertised yesterday, today I am going to try giving some insight as to what happens during a core meltdown,

 

specifically as might apply to the types of reactors at the Japanese plant. Unfortunately, it is impossible to do

 

that without having to use a lot of boring technical and scientific stuff. A logical starting place is to describe

 

the basics of how a reactor core is constructed. The nuclear fuel is usually in the form of uranium oxide pellets.

 

The pellets are placed in metal tubes (usually zirconium, sometimes aluminum, and much less frequently, stainless

 

steel) that are sealed at both ends. These are called fuel rods. The metal wall of the rod is usually referred to

 

as the "fuel cladding," and is the first of many engineered barriers between fuel and public. In most reactor

 

designs, the fuel rods are assembled into 'fuel bundles,' which are arrays of tens to possibly hundreds of

 

individual rods. As well as fuel rods, the bundles may contain spacer rods that only have structural material in

 

them (no fuel), or possibly rods that are loaded with a 'nuclear poison' instead of fuel. In this case, 'poison'

 

does not necessarily mean the material loaded in the rod is toxic to human health, but that it has the ability to

 

'poison' the fission chain reaction by absorbing neutrons without an accompanying nuclear fission. Typically used

 

nuclear poisons are halfnium, cadmium, and boron. The spacer rods and poison rods are used to shape the neutron

 

flux profile across and to equalize the amount of heat production across the cross section of the reactor. As well

 

as rods, the bundles have several structural elements, such as bundle end plates having channels to direct the flow

 

of cooling water into and out of the bundle, spacer elements to prevent bowing of the rods, and edge posts that the

 

various structural elements are attaached to. In some commercial reactors, the various rods are inserted

 

individually into the core rather than being bundled. The completed reactor core will contain thousands of

 

individual rods that are arranged in a roughly cylindrical shape. Along with the fuel rods, the core also contains

 

control rods...these are 'poison rods' that can move into or out of the core to control the fission chain reaction,

 

including entirely stopping the fission process, or "turning off" the reactor. The core is placed into a reactor

 

vessel, which is essentially a stainless steel tank with walls varying from six to ten inches of solid steel. Along

 

with the core, the reactor vessel also contains a lot of structure that routes the cooling water through the

 

reactor. The top of the reactor vessel consists of yet more structural components, motors that move the control

 

rods, instrumentation clusters, and other good stuff. Collectively, this part of the structure is referred to as

 

the 'containment head,' 'closure head,' 'top hat,' or some other term of endearment specific to the reactor

 

facility.

 

What points should one glean out of all this discription? First, a nuclear reactor is an extremely complex device,

 

and is carefully designed, configured, and constructed to enable it to attain a controlled nuclear chain reaction.

 

Second, the nuclear fuel is only a very small fraction of the mass of material comprising the reactor. Third, the

 

reactor is housed in a very substantial container that is the primary means of protecting the public from the

 

nuclear fuel and its waste products; however, as substantial as it is, it has its weak points and vulnerabilities,

 

especially in the closure head.

 

Now on to the meltdown. Prior to the earthquake, at least some of the affected reactors were operating at power,

 

fat, dumb, and happy. The earthquake hit, and automatic protective systems shut down the reactors by rapibly

 

inserting the control rods into the reactor cores. Heat generation in the core dropped drastically, the turbines

 

tripped off the line, and backup power supplies kicked in. However, since 7 percent of the heat produced in the

 

reactor comes from the decay of radioactive fission products and only time is going to decrease that production,

 

core cooling is still needed. The Coolant pumps are still operating, and cooling heat excangers are easily handling

 

that heat, and there is no evidence anywhere that any of the reactor containments have been damaged, all is still

 

well with the world....a big earthquake occurred, and all the safeguards worked as designed. Now, several minutes

 

later, along comes a 30 foot tall flood of seawater sweeping away everything it contacts...the transformer yard

 

connecting the complex to the electrical power grid is submerged and shorted out by seawater. The transmission

 

lines are swept away. The emergency diesel generators are shorted out and drenched in seawater. The lights go out,

 

and some feeble battery powered emergency lights come on. The coolant pumps, which moved the decay heat from the

 

reactor core to the emergency cooling heat exchangers stop running. All plant instruments not provided with battery

 

backups no longer work. The plant operators start to realize that their world just turned brown and they are in a

 

world of hurt. Minutes now feel like hours as the operators try to determine the condition of their reactor plant.

 

(So far as the time dialation, I can verify that by personal experience, having been the plant operating supervisor

 

on a reactor plant that totally lost all electrical power. In my case, the external power grid was still operating,

 

and it was possible to reenergize all critical systems within minutes...that doesn't change the panic you feel when

 

you realize the only electrons moving in the plant are in the battery-powered emergency lights. And, the hours if

 

subjective time that passed until we got the essential equipment running was really less than five minutes.) The

 

first and foremost thought in the plant operators is that core temperatures are going to start going up toward a

 

core damage event unless some cooling water flow can be started and maintained. Here I'm just guessing, based on a

 

general knowledge of various reactor plant design, but there is likely a stopgap reservoir of emergency cooling

 

water available that can be moved into the core by air pressure from banks of high pressure air tanks. This will

 

provide cooling for a short interval of time in the absence of eletrical power, but once that is gone, there is go

 

good means of moving cool water through the reactor core.

 

Again, I'm guessing at exact numbers, but at the start of the festivities, the water temperature in the core is

 

probably around 600 degrees F, and the temperature at the inside of the reactor fuel is about 700 degrees F. The

 

temperature difference between the center of the fuel and the surface of the cladding needed to remove the decay

 

heat is less than 100 F degrees. As long as the amount of heat being generated by the fission products can be moved

 

from the surface of the fuel rod to somewhere/something else, there is no danger of damaging the rods or releasing

 

fuel, since the melting point of the fuel cladding is a bit more than 3300 degrees F. All is well (relatively)

 

until the plant operators run out of cool water that can be moved into the core. Once that happens, the decay heat

 

starts increasing the temperature of the water in the reactor vessel. Even though at a temperature far above the

 

212 degree F boiling point of water that immediately comes to the minds of most of us, the pressure in the core is

 

keeping it in a water state instead of steam. Somewhere in the piping attached to the core is a steam bubble with a

 

pressure correspoindint to a 600 degree F boiling point. Since retiring, I no longer have a set of steam tables at

 

my fingertips so am just shooting from the hip, but that pressure is probably somewhere around 1800 pounds per

 

square inch (psi). To this point, heat removal from the fuel rod has been by conduction into the water, which is a

 

very efficient heat transfer mechanism. The surface temperature of the cladding is only slightly (10 or 15 F

 

degrees) greater than the water temperature. Since heat is still being produced in the fuel by nuclear decay, the

 

water temperature in the core now starts increasing (the heat transferred into the water has no removal route, so

 

starts increasing the water temperature. The hotter the water gets, the hotter the fuel temperature becomes in

 

order to keep moving heat out to the coolant water. The water temperature next to the fuel rod is now higher than

 

the boiling temperature correspoinding to the water pressure, so boiling starts to occur. This is still a very

 

effecient mechanism for heat transfer, and the Japanese reactor plants are designed for boiling to occur in the

 

reactor vessel (they are a class of reactors referred to as boiling water reactors). However, since coolant is no

 

longer being pumped through the vessel, a steam bubble now starts forming in the top of the vessel. At this stage

 

of the accident, core temperatures slowly increase, pressure slowly increases, and the size of the steam bubble

 

slowly increases. So far they are within the systems design limits, so no serious damage is occurring...however, as

 

the cladding temperature elevates, it starts undergoing a metal-water reaction. In layman's terms, it starts

 

rusting...the zirconium metal on the surface of the rod gets converted to zirconium oxide by robbing oxygen atoms

 

from the water. A little rust never really hurt anyone, right? Wrong...when the oxygen is removed from the water

 

molecule, the two hydrogen atoms left behind combine into a Hygrogen gas molecule, and start collecting in the top

 

of the reactor vessel. That is bad....but not as bad as events to come.

 

As the accident progresses, the steam bubble at the top of the core becomes large enough it starts uncovering the

 

fuel rods..this is very bad. The portion of the fuel rod no longer in contact with water now has convection as a

 

heat removal mechanism, which is not very efficient. The temperatures of the exposed region of the rods now start

 

really ramping up. Some of the heat produced in the exposed region is removed by conduction down the side of the

 

fuel rod to the part of the rod still in contact with the remaining water, and some of the heat in the exposed

 

region starts to be removed by black-body radiation. However, as the steam bubble continues to grow, heat cannot be

 

removed from the exposed portion of the rods as fast as it is being created, and temperature in that region

 

continues ramping up. The larger the steam bubble grows, the faster the temperatures increase in the exposed

 

portions of the core. As the exposed cladding increases in temperature, the amount of heat removed by black-body

 

radiation increases....however, the really bad part of this is that the surface temperature needed to remove the

 

heat being produced only by radiation is greater than the melting point of the zirconium. As well, the hotter the

 

clad becomes, the greater the amount of oxidation through metal-water reaction and the greater the amount of

 

hydrogen collecting in the vapor region of the core. Along with all this, many of the fission products in the fuel

 

are gasses. As the fuel temperature goes up, these gasses start expanding and increasing the internal pressure of

 

the rods. The fuel pellets start cracking and fracturing. The thermal stresses in the core are causing the fuel

 

rods and structural pieces to start deforming, cracking, and otherwise turning into scrap metal. At some point in

 

this nightmare, the temperature of the upper regions of the core are large enough to melt the cladding, and possibly

 

even the oxide fuel pellets. Meltdown has started. The metal temperatures are great enough the cladding and other

 

metals are not just rusting, but are actuall burning. The steam bubble in the top of the vessel is now collecting

 

not just hydrogen, but radioactive gasses from the fuel. Molten cladding, structural material, and possibly even

 

fuel starts flowing down into the bottom of the reactor vessel. The bottom of the vessel still contains some

 

water...the melt falls into that water and, since it is now thousands of degrees F greater than the water's boiling

 

point, instantaneously boils away any water it contacts, boiling so rapid it actually acts like an explosion, and in

 

fact this termed a "steam explosion. It creates a pressure front that moves up the reactor vessel, continuing the

 

process of converting the structure to scrap and knocking large pieces loose that fall into the bottom of the

 

vessel. These steam explosions act like a crankcase explosion...if it doesn't knock a hole through the block, it is

 

damned well going to blow out the seals...which is what is happening in the reactor closure head. The pressure

 

spikes break down the seals between the vessel head parts and between the closure head and the reactor vessel. The

 

radioactive gasses and hydrogen are released from the primary containment.

 

And, at this point, someone is going to shout out "China syndrome." The core is now going to melt through the

 

bottome of the vessel, then melt through the concrete floor, and then continue melting through the soil towards

 

China (which for these reactors would be difficult, as that would require the melt to start going perpendicular to

 

the force of gravity. Please pardon my levity (sarcasm, actually) and bluntness of expression....but my reply is a

 

resounding "bullshit." The china syndrome makes a thrilling movie and a great boogieman for the anti-nuke crowd,

 

but it cannot possibly happen. Consider this....as the core melts, the heat producing fuel is being diluted by

 

melted cladding and structural materials, so the specific heat production is decreasing. At the same time, the

 

volume of the material is increasing, so there is more area for heat removal. And, far more significant, when the

 

blob hits the bottom of the vessel, the heat transfer mechanism reverts back to conduction, which starts removing

 

heat from the glob far faster than it is being created by the fuel. As well, the melt no longer looks like a

 

sphere, but becomes a plate....the ratio of surface to volume is increased a hundredfold. The temperature of the

 

glob drops precipitously, and very quickly is less than the melting point of the blob...it solidifies, and heat

 

removal is great enough (the vessel makes one hell of a big heat sink) to keep it solid. At TMI, which had a very

 

large portion of its core melt, the slag in the vessel bottom did melt about 3/8-inch into a small area of the

 

vessel bottom....leaving it at nearly six inches of unaffected steel to contain it. Nothing gets out of the bottom

 

of the reactor vessel, and hydrogen production tails off to zilch. Hydrogen and radioactive gasses have been

 

released from the vessel, but are still within the containment barrier that exists around the reactor system. If

 

that containment has been breached, those gasses escape out into the secondary containment. In reality, hydrogen is

 

so mobile that it is nearly impossible to contain...the best the primary containment is going to do is slow down the

 

rate it gets released. The hydrogen gas inevitibly builds up in both the primary and the secondary containment

 

regions. Hydrogen burns...and, if it builds up to more than 10% of the air volume, it explodes. At Three Mile

 

Island, the hydrogen buildup in the reactor building ignited before reaching an explosive mixture. There was a

 

pressure pulse in the TMI building, but it was not enough to breach the building walls. At the Japanese plants, the

 

hydrogen reached an explosive mixture, with the result of the blown out building walls and dust plume we have been

 

seeing over and over again. And that is the anatomy of a core meltdown.

 

For several reasons, there is going to be a greater release of radioactive material from the Japanese plants than

 

from Three Mile Island. It will primarily be in the form of radioactive gasses with some of the lighter metals

 

(during a fuel failure, Cesium acts more like a gas than a metal...as rapibly as it moved through the Power Burst

 

Facility reactor building during a fuel failure test, I swear it even moved upstream in the ventilation ducts.) How

 

much material gets released to the public is going to depend largely on how well they can maintain intactness of the

 

primary containment barrier. In no event will the reactors release radioactives in amounts that even begin to

 

approach the severity of the Chrenobyl accident. That said, the fuel in the spent fuel cooling ponds is a totally

 

different animal, and what I'm mainly concerned over. If they melt, it goes directly into the atmosphere. The

 

mitigating part is that the rods in those pools have had far more time for the fission product decay, therefore

 

likely producing a lot less decay heat relative to the rods in the reactor vessels. My number one grandson may yet

 

get an answer to his question about what would happen during a meltdown with a complete failure of the containment

 

structure....however, we still will not be talking about Chrenobyl-type releases.

Edited March 19, 2011 by firebird77clone

[BONMYI]

Thanks, enlightening, Great post..

 

 

Dave

[secinv]

I personally believe that Nuclear Power is the right way to go.

[uplander]

Wow................

I have over 30 years in nuclear (military and civilian) been listening to so many people that do not know what there talking about on the news, it is refreshing to hear someone who knows what they are talking about!

[Indian Brave]

Additional info!

 

A great post and very informative!

 

It mentions Cesium... so how does radioisotope Xenon-133 from the nuclear incident at Fukushima arrive on the West Coast of USA 9 days later?.

 

 

http://www.kndu.com/Global/story.asp?S=14284357

 

First West Coast radiation detection

RICHLAND, Wash. - Pacific Northwest National Laboratory in Richland detected trace amounts of the radioisotope Xenon-133 from the nuclear incident at Fukushima. (my emphasis).

 

This occurred Wednesday, March 16, and was the first detection in the continental United States. Subsequent measurements here at PNNL were a bit higher but again significantly below levels that would impact public health. On Friday, March 18, sensors here also showed the presence of iodine isotopes, but at even lower levels than the xenon isotopes.

 

Read the rest etc at the link.

 

Other reports suggest that the worst damaged Fukushima reactor number 4? was actually using and also had stored - MOX fuel rods - which are somewhat different to your normal garden variety Uranium fuel rods - (and for which the General Electric mark 1 boiling water reactor of the types used by Daiichi at Fukushima, were never designed for and are far more harmful to human health in a meltdown scenario) in that they are reprocessed spent nuclear reactor rids from France and contain the much more harmful and potentially magnitudes more dangerous too human health, Plutonium - also useful in manufacturing nuclear weapons.

 

Containment vessel breach is definitely confirmed now by the Japanese, and the radioisotopes now being measured on the other side of the pacific in West Coast mainland USA, might maybe tell us something more about whats really going down?

 

There are 3 ways you can die from radiation exposure (and I don't claim to be any kind of a Gnu Cue Lar expert having no more knowledge than that gained thru making gnu cue lar bombs out of glow in the dark watch faces in my basement garage as a hobby too kill rats, that's a joke Joyce you homeland security peeps can stand down).

 

1. From the air you breath - easy fix stop breathing and you won't die from nuclear radiation sickness (but might from lack of oxygen but thats a different story so we don;t need to go there just yet).

 

2. From the water you drink.

 

So far the water in the USA remains safe however there are reports today that the drinking water in Tokyo city is already contaminated now and unsafe to drink.

 

So unless your planning a holiday there and intending to shower in it or drink from the taps in Japan, then you SHOULD be safe!

 

Ohh don't go drinking any imported "Mt Fuji Snowmelt Pure Fresh" bottled water either (Specially any made from yellow snow!).

 

3. From the food you eat (injest)!

 

Well again Japanese food milk spinach etc is already contaminated according to press reports today!

 

BUT - here's the biggee!

 

Nations near bye too Japan who produce food crops (or manufactured goods as well) that's exported around the world could well be contaminated up too a week ago if they are close to Japan and the wind blew that way for any length of time straight after the reactor explosions.

 

Just twixt us, The air monitoring stations I looked at online between the reactors at Fukushima, and Toko - increased their readings from normal Japanese background radiation levels of 40 microseiverts before the earth quake to over 1200 Microseivertson the day we saw the steam explosions on the TV news at the Fukushima plant.

 

Thats a 3000% increase - with levels of 100 micrseiverts considered injurious too human health and 1000 microseiverts potentially lethal to humans on the US radiation risk scale I saw online.

 

Elevated levels were detected as stated in Tokyo according too the press.

 

If you draw a straight line from Fukushima, and continue it on past tpkyo - guess where it leads?

 

Yes across the sea straight to China!

 

Why should that worry YOU (or me for that matter?)

 

Well - how much of your food is imported from China - non right?

 

 

You'd think this home brand bag of vegetables from my local multinational corporation owned supermarket, would be local produce right, specially since it is selected for freshness!

 

 

Well you'd be wrong because it was grown and packaged in CHINA - it says so right there on the back in the fine print that non of us read!

 

So - just how much contaminated "Chinese" product, are we all buying and eating - does the contaminated Chinese product sit in a deep freeze at the supermarket and while in storage there in their cool rooms and freezers out the back alongside your own homegrown clean green produce and cross contaminate that with its radiation as well and do the same too all the locally grown food in your home freezer too?

 

Of course you all take your personal Geiger counter dosimeter too the supermarket and wave it around the frozen vegetables freezer to see if anythings contaminated before you buy it don't you

 

Well a week ago you could have bought one out of the Ukraine where most of them are manufactured for about164 bucks plus postage of another $31 on evilbay but non of us did, because we don;t need one right?

 

Well this week they START at $800 and the waiting lists are already MONTHS behind on a triage basis supply as they come off the manufacturing line!

 

Talk about milk a bad situation for a fast buck! Them Ukranian's are diabolical I tell you!

 

So...

 

Your not worried about your food because you never buy food from China (meaning your too blind too read the fine print on the back of the pack.

 

I guess you don't buy any cheap product out of China from the Wallyworld Chinese Hardware cjhains either.

 

I'm guessing you also won't be buying one of these anytime soon either.

 

 

Imagine sitting all day every workday in a company supplied fleet vehicle made in China that was sitting out in a shipping yard in China waiting for shipment on the days after the Japan earthquake last week - and got totally exposed too the 1200 microseiverts plume!

 

I wonder what that does too your radiation doeage when you get exposed too it forevery day over the next 5 years or so?

 

And of course we all take ourpersonal geiger counter and dossimeter too the car yard with us and too wally world too check the product we buy and bring back into our home.

 

Building a house are we? What about that load of cheap Chinese manufactured drywall rocksheet from wally world, is that made with radioactive contaminated Gypsum too?

 

I guess your going too sheet out the new baby's nursery room with that eh?...to keep momma happy!

shame about the childhood long doses of radiation that new child will be accumulating every time she is put too bed or taken anywhere in that cheap new Chinese 4wd vehicle...never mind the approved child restraint from China (that probably glows in the dark) will keep her/him "safe" in case of an accident might actually be what kills her from radiation poisoning in the end aged 16 or will it be the radioactive vegetables that she gets mushed up once she is on solids, out of a bag from China bought at the local supermarket be what eventually causes her fatal leukemia?

 

Just listen too the Govt peeps - they will tel you all you need to know about the dangers too you from this catastrophe in Japan!

 

Move along people - nothing happening here, nothing too see - your all quite safe.

 

You can trust the multinational corporation owned supermarkets with your family's health - they will check all the food and consumables coming in from China for nuclear contamination on your behalf, after all that's what they REALLY care about, they aren't only motivated by their fat end of year bonuses and the bottom line and generating dividends for shareholders!

 

Yup - everythings sweet and you got nuthin too worry about!

 

It's true - the Govt said so and they wouldn't lie, after all - Saddam really did have weapons of mass disappearance and everyone knows he flew one of the planes that hit the twin towers on 9/11 - it wasn't a false flag attack by the Israelis to get the US moms n dads to send 5000+ of their Goyim Kids to die in the battle against Iraq, so that the Israelis "chosen ones" kids didn't have to go do the fighting and dieing!

 

Yup yup yup.

 

Nuthin to see here all right!

 

Good luck with that hope and change!

 

You know - for all of Odumbo's faults and broken promises - at least up until yesterday he hadn't started any NEW illegal wars of aggression against innoicent wommins and kids in the samnd arabs nations like Dubya before him, but NOW hes gone and prived tha he is just as bad as the others with the attacks on Libya.

 

I guess when your already fighting simultaneous wars on 2 fronts and $13+ trillion in the hole financially with the country teetering on the brink of bankruptcy, whats one more war in North Africa this time?

 

Talk about a sitting duck for your enemy's (Iran & Russia, not too mention Syria, North Korea and China for starters) - seeing the USA stretched thin across the world with 3 simultaneous wars and supply lines thin and unable too be protected, and the country so broke no one but your own federal reserve will your debt any longer - this would be the ideal time to give the USA a ass whupin they would neverforget.

 

If I were afterdinnerjacket from Iran, I'd be thinking about busting out of Iran and into eastern then western europe and when they do and they get control of all the nukes there - they just might aim them at good ol mainland USA and push the damn red button.

 

When that happens - well guess what? - contamination from the Japan Nuclear Power station meltdown will be the last of your problems!

 

Cheers

[maninbox]

Very informative article. Thanks for posting. Very impressed with the senior Grigg's knowledge of the subject. .

 

Eron, while I'm at it, thanks for your service in Afghanistan as well.

You are an American patriot although you may not feel like one right now.

[Indian Brave]

 

Ya'll SURE you don't glow now?

 

Can't wait to get delivery of my new Japanese Toyota 200 series twin turbo diesel land cruiser wagon - a steal at a tad over $120K, and just think = I'll be getting my daily radiation treatment dosage every time I sit in it for the life of the vehicle!

 

Yes and that Honda Yamaha Suzuki motorbike - all that radiation between the missus legs off the irradiated seat, she won't need no Brazilian bikini wax job - her pubic hairs will likely fall out bye themselves!

 

Ohh yeah - the "fallout" over this cat arse trophy for Japan will essentially finish off their economy - you won't be able to give away Japanese product into the foreseeable future for generations is my best guess.

 

Cheers

Edited March 26, 2011 by Indian Brave

[Mickdanewf]

Yes Thx FB77....a great post and an unfortunate situation!

....and what Kevin said....

[Indian Brave]

You don't glow now.

 

Why?

 

Because the glow goalposts have been shifted to "accommodate the japan nuclear crisis" by some 100,000 fold!.

 

http://www.activistpost.com/2011/03/epa-to-help-mainstream-media-obscure.html

 

Nothing to see here folks - move along move along - just keep your faith in all the smoke and mirrors.

 

Cheers & jolly good luck with that!

[RCH]

We had to endure the antics of Senators Feinstein and Boxer the other day at San Onofre Nuclear Generating Station (SONGS). What a waste of resources.........

 

My condolences go out to the Japanese people impacted by the tsunami that has killed thousands, while the medias attention has gone into hyperbole mode over the nuclear incident that has not killed a single soul.

[Doc Loco]

We had to endure the antics of Senators Feinstein and Boxer the other day at San Onofre Nuclear Generating Station (SONGS). What a waste of resources.........

 

Don't let those resources go to waste...show F&B the 'hot tub'.