Nuclear Catastrophie

[Dean Los Angeles]

A US agency helping Japan tackle its nuclear crisis at a stricken nuclear power plant says there is no water in one of the reactor's pools, leading to "extremely high" radiation levels.

The announcement by the chairman of the US Nuclear Regulatory Commission (NRC), Gregory Jaczko, came as the operator of the Fukushima Daiichi plant said it had almost completed a new power line that could restore electricity to the facility and avoid a meltdown.

Mr Jaczko, who was briefing US politicians in Washington, said the NRC believed "there has been a hydrogen explosion in this unit due to an uncovering of the fuel in the spent fuel pool".

"We believe that secondary containment has been destroyed and there is no water in the spent fuel pool. And we believe that radiation levels are extremely high, which could possibly impact the ability to take corrective measures."

The spent fuel storage is in the upper right labeled "fuel storage pool".

[Tman]

Thank you, that explains a lot!

[hotrod]

Now to go look up the decay rate on nuclear stuff.  My evening is full.  My heart is empty.

Geo

It varies a bit depending on what the fuel mix is, but a close approximation often used in nuclear weapon planning for fall out,  is that the exposure rate decreases exponentially at an exponent of -1.8 (or very close to that value). The short hand rule of thumb is that for every 7 fold increase in time, the exposure rate decreases by approximately a factor or 10.

Once the reactor shuts down (the emergency scram) the decay products begin this exponential decay. 7 hours after the shut down the radiation intensity of the decay products would be about 10% of its initial value, 7x7 hrs (2 days) after shut down the radiation intensity would be 1% or the original value. After 2 weeks 0.1% of the original value. As you can see the initial decay rate is very rapid, but begins to slow down as only the long half life isotopes are left.

The fission products in an operational reactor are a bit different than a nuclear weapon because the fission process is spread out over time, rather than all happening at a single moment in time. As a result the decay products from fission that occurred weeks or months ago, are in a much later stage of decay that the decay products of fission that occurred just moments before the shut down. As a result the decay is not as abrupt as it would be for a weapons fall out.

This however only applies to the full load of decay products from nuclear fission. In this sort of situation you get fractionation where only certain radio nuclides are mobile enough to get out of the reactor.The nobel gasses decay very rapidly (which accounts for the sharp but brief spikes in radiation as a puff of material escapes the containment. The two most prominent radio nuclides are Iodine 131 which has a 1/2 life of 8.02 days (ie every 8.02 days half of the remaining I 131 ceases to be radioactive). This is easily absorbed by the body and concentrated in the thyroid gland, and is the reason behind issuing potassium iodide tablets to flood the body with non-radioactive iodine to minimize uptake of radioactive iodine.

The second important isotope is Cesium Cs 137 which is a beta and moderate energy gamma emitter but has a half life of 30.17 years, so it takes a significant time to decay away to nothing. Medically it acts much like potassium and the good news is that it washes out of the body fairly quickly, taking only about 70 days for 1/2 of it to be excreted if any is ingested.

The third important radio isotope is probably strontium 90 which has a 1/2 life of 28.8 years. Only about 20% - 30% of the strontium 90 ingested is actually absorbed by the body. The bad news is that it is treated by the body as an analog of calcium and gets deposited in the bones. Its biological half life is about 18 years. Since it mimics calcium, the source of a persons calcium intake impacts how much Sr 90 they will absorb. Persons who get most of the calcium from milk products will take up less Sr 90 than people that get most of their calcium from vegetables, because the cow that makes the milk, preferentially filters out some of the Sr 90.

One of the problems with cooling the reactor core and rods with sea water, is that common salt when irradiated with neutrons captures neutrons and converts to a radioactive isotope Na 24. Sodium 24 has a short half life of 15 hours but it is a gamma emitter so the salt in the sea water could create a new short lived radiation hazard if it is exposed to high neutron irradiation in the core. I am not sure if the neutron flux in the shut down reactor is high enough for this to be an issue there or in the spent fuel rod pool, as I do not know how much fission occurs in the fuel rods in the cooling pool. It is obviously below the threshold to support a chain reaction but it may be high enough to activate some of the salt in the sea water.

Larry

[Tman]

All I know is there were some big 'splosions by looking at those reactor buildings!

[Stan Back]

Slim, I don't know if this guy knows what he's talking about, but he's sure got me convinced he does.  Thank you for not closing this off as we know it's a little off our usual subjects.

Stan

[wobblywalrus]

It is a good thread for learning about an important subject we do not usually deal with.  Explosions, meltdowns, etc are not totally unfamiliar for most of us.

[DocBeech]

As a former vet of Iraq and someone that has worked in the medical field yes he is mostly correct. The only part that he left out is that radiation does not hurt the body hollywood style. You don't enter the reactor and come out looking like you just had the workout of your life unless you had incredible doses of it. More over it can take up to weeks to show signs and symptoms of radiation poisoning and months to die from it. Some of the firefighters might not even begin to show symptoms of poisoning until April. Those who did recieve lethal doses might live another 6 months. Usually it takes 30-90 days to die from radiation poisoning. Radiation Poisoning is a very slow and painful death. Organ failure, tissure burns, loss of apetite followed by intense stomach cramps. Diahrea, Headcahe, and Fever are pretty good signs that sometimes show themselves within 10 min, or some symptoms can wait 4 weeks before presenting themselves like slow healing injuries, bloody vomit or stool, fatigue, disorientation, and other signs as well. Basically some of these exposed peopel could be the walking dead and not know it.

The other problem I havn't seen a lot of talk about is food contamination. Cesium 137 with its half life of 30 years means it has 600 years before it reaches safe levels. So that means it could possibly be spread through the food supplies of the pacific ocean for a long time. The same goes for the more dangerous Strontium 90. Remember once absorbed it doesn't always leave. So lets say it deposits itself in your body, either one of these. Now you live in seattle and love to eat crab. Just an example. You continue to eat crab from the pacific for 30 years or more. That Cesium 137 will still be in the food chain. So you are continuing to add to the levels in your body. Unlike a toxin once deposited in your bones, it will continue to radiate until you die.

[sailingadventure]

This may be the dumbest thing I`ve ever written, but if there is a complete melt down, would detonating a low power nuclear weapon burn up the remaining radioactive material or just spread it around?

[coloradodave]

As a former vet of Iraq and someone that has worked in the medical field yes he is mostly correct. The only part that he left out is that radiation does not hurt the body hollywood style. You don't enter the reactor and come out looking like you just had the workout of your life unless you had incredible doses of it. More over it can take up to weeks to show signs and symptoms of radiation poisoning and months to die from it. Some of the firefighters might not even begin to show symptoms of poisoning until April. Those who did recieve lethal doses might live another 6 months. Usually it takes 30-90 days to die from radiation poisoning. Radiation Poisoning is a very slow and painful death. Organ failure, tissure burns, loss of apetite followed by intense stomach cramps. Diahrea, Headcahe, and Fever are pretty good signs that sometimes show themselves within 10 min, or some symptoms can wait 4 weeks before presenting themselves like slow healing injuries, bloody vomit or stool, fatigue, disorientation, and other signs as well. Basically some of these exposed peopel could be the walking dead and not know it.

The other problem I havn't seen a lot of talk about is food contamination. Cesium 137 with its half life of 30 years means it has 600 years before it reaches safe levels. So that means it could possibly be spread through the food supplies of the pacific ocean for a long time. The same goes for the more dangerous Strontium 90. Remember once absorbed it doesn't always leave. So lets say it deposits itself in your body, either one of these. Now you live in seattle and love to eat crab. Just an example. You continue to eat crab from the pacific for 30 years or more. That Cesium 137 will still be in the food chain. So you are continuing to add to the levels in your body. Unlike a toxin once deposited in your bones, it will continue to radiate until you die.

OMG, you read this and it makes you wonder why we ever thought this was a good idea, sounds like a truly horrific way to die.

[Dreamweaver]

Well, once upon a time there was this insane house painter named Adolf

[hotrod]

This may be the dumbest thing I`ve ever written, but if there is a complete melt down, would detonating a low power nuclear weapon burn up the remaining radioactive material or just spread it around?

Short answer is no that won't work, there is no way known to interrupt the radioactive decay process. Once started the radioactive elements begin their step wise decay toward lead or some other heavy non-radioactive elements.

As far as the radiation poisoning -- yes acute over dose is an ugly way to die, but the exposure levels they are talking about are no where near lethal. Radiation exposure is not "exact" the LD50/30 dose of acute gamma exposure is considered to be 450 RAD absorbed dose, but some folks have received in the neighborhood of 1000 and are still walking around.

Regarding the Cs137 and Strontium 90 in the food chain -- been there done that already conducted that experiment with open air testing of nuclear weapons that put several orders of magnitude more radioactive Cs137 and Sr90 in the atmosphere/pacific than these reactor incidents will ever accomplish, and you guys have been eating that trace radioactive material in your sea food for 60 years now. They did the same thing with large parts of Utah that was down wind from the Nevada test site and there are no mutant rabbits to show for it (except for that invisible one named Harvey).

Larry

[Seldom Seen Slim]

I remember the worry about contaminated milk from cows that grazed on grass that had collected Strontium 90 in fallout.  That's as close as I can recall about tainted food.  Fish?  Well, lucky for us - we don't eat much or often, so our chances of catching a doze of radiation are pretty limited there.  And most of what we eat is lake trout caught in the great lakes.  Keep on chomping.

On the subject of whether this very non-LSR topic should be discussed on the LSR website and Forum -- I personally am enjoying and learning plenty from it and don't want to have it come to an end.  If a bunch of members asked me to cease and desist the ongoing topic I would -- but 'til then I'll let it run.

[4-barrel Mike]

For a different perspective on radiation poisoning, try arch-conservative Ann Coulter's newest (March 16) column "A GLOWING REPORT ON RADIATION":

http://www.anncoulter.com/

Mike

[Geo]

OMG, you read this and it makes you wonder why we ever thought this was a good idea, sounds like a truly horrific way to die.

No worse than being swept to sea after the tsunami, buried alive in an earthquake, having cancer, a virus like HIV, an illness like Amyotrophic lateral sclerosis (ALS), often referred to as "Lou Gehrig's Disease," being hit by a bus and in a coma for months before passing, etc.  Time where one can live the slow death in any form is awful. The movies have made us perceive terrible things that do not occur because we like the scary side of things.  Much like the news.

I hope we will learn from this event and build smarter in the future.

I had heard bits about the the things Ann Coulter writes about but never gathered together. My fear of nuclear power generation is going away through the knowledge gained in this thread.

Thanks for everyone's contribution.

Geo

[Dean Los Angeles]

The radiation is the key to all of this.

If this had been a coal fired plant, natural gas fired, hydroelectric plant etc., the cleanup would have been under way and out of the news.

The legacy of this will go on for the next decade or more.

Until someone says this is under control the last page has yet to be written.

You guys build some incredible stuff, so tell me how you would fix this. I was driving to work this morning and heard they should have power by tomorrow. The pump motors were damaged by sea water and they are planning on powering pumps outside the plant. That means they have to somehow run pipes into the reactor. That seems like it would take weeks under decent conditions.

The radiation levels are going to make that super difficult. You need knowledgeable trade people. Anyone working will have a brief time to get the job done and never come back.

The interior of the plant suffered an explosion. It was heard 25 miles away. So just imagine the damage to the wiring, motors, pipes by a thousand pound bomb or something like that. The building structure and debris has collapsed over everything on the interior.

The integrity of the spent fuel pool is in doubt. If it won't hold water it doesn't matter how much you pour in. The aerial effort so far had put 65 tons of water into unit #3 to put water in. I doubt if a fraction of that actually hit the building or came close to the spent fuel pool based on the video. I heard the pool holds 7,500 tons of water.

I also heard an interview with a Russian and American nuclear expert. They looked at the records for unit #4 over the last several years and they say the pool was pretty full before the de-fueling in December. Although illegal, they think the very fresh rods removed in December may have been double stacked. Instead of 16 feet of water they would have had a few feet at best. Speculation, but not out of the question.