SLEEP TIGHT TONIGHT

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Henry Vilas
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Re: SLEEP TIGHT TONIGHT

Postby Henry Vilas » Tue Mar 15, 2011 10:18 am

Prof. Wagstaff wrote:
Henry Vilas wrote:...strontium-90 ended up in milk and was then absorbed into children's teeth. Cancer rates went up as a result.


While I'm not necessarily doubting this conclusion -- it seems reasonable enough -- it is always worth pointing out that correlation does not prove causation. Lots of other possible factors could explain rising cancer rates.

From WIKI:
The results of a study of hundreds of thousands of teeth collected by Dr. Louise Reiss and her colleagues as part of the Baby Tooth Survey showed that children born after 1963 had levels of 90Sr in their deciduous teeth that was 50 times higher than that found in children born before the advent of large-scale atomic testing. The findings helped convince U.S. President John F. Kennedy to sign the Partial Nuclear Test Ban Treaty with the United Kingdom and Soviet Union, which ended the above-ground nuclear weapons testing that placed the greatest amounts of nuclear fallout into the atmosphere. A set of 85,000 teeth that had been uncovered in storage in 2001 were given to the Radiation and Public Health Project. By tracking the individuals who had participated in the tooth-collection project, the RHPR published results in a 2010 issue of the International Journal of Health Service that showed that those children who later died of cancer before the age of 50 had levels of strontium 90 in their stored baby teeth that was twice the level of those who were still alive at 50.[3][4]

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Re: SLEEP TIGHT TONIGHT

Postby kurt_w » Tue Mar 15, 2011 10:39 am

narcoleptish wrote:Kurt, how long have you been waiting to casually drop the term "seiche" into a conversation?


No comment.

Just kidding. Very informative post and I have a question. Does the sea water being used to cool the reactors in Japan become radioactive or polluted in any way, and then is it just pumped out to sea again?


This is one of those maddening questions where the answer could be anywhere from "yes" to "no" and it's almost impossible to find out until long after the fact. Over the past three days I've spent a huge amount of time reading technical discussions of what's going on at those reactors, and I still can't figure out exactly what's happening.

Some of the seawater gets heated to high temperatures, turns into steam, and is released into the atmosphere to keep the pressure from getting too high.

However, the heated water and steam also reacts with the zirconium in the cladding around the fuel rods, damaging the cladding and splitting the H2O, producing hydrogen gas, which accumulates at the top of the reactor building and eventually explodes in a dramatic PUFF! The reaction with the cladding and fuel rods also liberates radioisotopes of cesium and iodine, which are carried out to the atmosphere during the steam-venting or the explosions, I guess. This is why they're distributing potassium iodide tablets as a precautionary measure, though so far the levels don't sound too bad.

I don't think large amounts of seawater are being circulated back out from the reactors and reaching the ocean directly. Radioactive materials vented during the steam releases and explosions will land on the sea surface and be effectively diluted by the very large mass of the ocean. That's not what concerns me here.

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Re: SLEEP TIGHT TONIGHT

Postby Prof. Wagstaff » Tue Mar 15, 2011 10:39 am

Thanks for the link, Hank. But there's nothing there that refutes my cautionary statement that correlation does not prove causation. Lots of things cause cancer besides Strontium-90. Are all of those causes accounted for in the study you cite?

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Re: SLEEP TIGHT TONIGHT

Postby Henry Vilas » Tue Mar 15, 2011 10:50 am

The study showed that those with higher levels of strontium-90 in their teeth had higher rates of cancer than those who did not. I consider that strong evidence.

And as far as nuclear waste and the oceans, it is common practice in the Navy to discharge radioactive coolant water directly into the sea. I was stationed aboard a submarine tender which stored such coolant water pumped from nuclear submarines. About the only time the tender got underway was when it dumped that contaminated water. We sailed just beyond the continental shelf and did figure eights while discharging that poison.

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Re: SLEEP TIGHT TONIGHT

Postby Huckleby » Tue Mar 15, 2011 10:51 am

I went to bed last night certain that the meltdown was coming. Now radiation levels are falling.

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Re: SLEEP TIGHT TONIGHT

Postby kurt_w » Tue Mar 15, 2011 11:07 am

"Meltdown" is not actually an unambiguous term. It's possible that one of the reactors has partially "melted down" already. Or ... not. The conflicting and uncertain information coming from that facility is maddening.

It wouldn't necessarily make a huge difference in terms of environmental impacts, though it would complicate things and make the cleanup more expensive and difficult.

Sounds like the recent large releases of radiation were associated with the fire at the spent fuel pool (sfp) not from the operating reactor itself.

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Re: SLEEP TIGHT TONIGHT

Postby Prof. Wagstaff » Tue Mar 15, 2011 11:24 am

Henry Vilas wrote:The study showed that those with higher levels of strontium-90 in their teeth had higher rates of cancer than those who did not. I consider that strong evidence.


I consider it strong evidence too. But it isn't proof.
There's a difference, Hank.

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Re: SLEEP TIGHT TONIGHT

Postby snoqueen » Tue Mar 15, 2011 11:53 am

The spent fuel stored at the Fukushima reactor sites is now considered to be at least as big a concern as the damaged reactors themselves, because the spent fuel is not housed as securely as the fuel in the reactors themselves.

http://www.thenation.com/article/159234 ... ave-danger

Quote from article:

" "...There is smoke coming from reactor No. 3, and steam coming from the spent fuel pool next to it. That indicates that the water in the pool is boiling. And that means the spent fuel rods are getting hot and could start burning.”

If the spent rods start to burn, huge amounts of radioactive material would be released into the atmosphere and would disperse across the Northern Hemisphere."


I think we aren't going to get any clear information from the reactor site for a while, because it seems the engineers and staff are in a complete panic. The situation has gone way beyond their training and experience, same as the Gulf Horizon blowup went way beyond the training and experience of the engineers and crew on the platform. Holding news briefings is probably the last thing on their minds.

The public here should want to know how well the spent fuel at US reactors is being protected in light of the present crisis.


HV: I also remember those "chocolate pills" or iodine pills from grade school in the 50s. The way it was presented to us at the time, our diets did not provide enough iodine for health due to the fact we lived so far inland. Iodine was supposedly found in sea salt but not our table salt. At some point we started to use "iodized salt" as table salt (think of those blue Morton Salt packages) and then the schools quit handing out the "chocolate pills." I never had any idea it was about protecting people against the effects of radiation until now -- are you totally sure that was the reasoning? I'm not disagreeing -- this is just a new angle to me. Since we were in the middle of the bomb shelter era, I would not be surprised if the pills were part of a 50's era civil defense plan.

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Re: SLEEP TIGHT TONIGHT

Postby narcoleptish » Tue Mar 15, 2011 12:46 pm

Question time:

How/why do spent fuel rods begin to heat up. "Spent" makes me think they aren't functional anymore.

kurt_w wrote:
However, the heated water and steam also reacts with the zirconium in the cladding around the fuel rods, damaging the cladding and splitting the H2O, producing hydrogen gas, which accumulates at the top of the reactor building and eventually explodes in a dramatic PUFF!


Is a certain amount of hydrogen needed before it is combustible? Would some kind of a periodic ignition system be possible that would ignite the hydrogen in smaller, less damaging "puffs" in times of emergency such as this?

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Re: SLEEP TIGHT TONIGHT

Postby Henry Vilas » Tue Mar 15, 2011 1:15 pm

narcoleptish wrote:Question time:

How/why do spent fuel rods begin to heat up. "Spent" makes me think they aren't functional anymore.

While no longer usable for fuel, spent rods are still highly radioactive.

Sno, while we were told that those iodine pills were needed because we didn't eat enough seafood, they were for protection against the effects of radioactive fallout, not only from above ground testing, but also because of the threat of nuclear war during the 1950s.

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Re: SLEEP TIGHT TONIGHT

Postby kurt_w » Tue Mar 15, 2011 1:38 pm

narcoleptish wrote:Question time:

How/why do spent fuel rods begin to heat up. "Spent" makes me think they aren't functional anymore.


OK, first of all, I'm not an expert on this -- my engineering background is civil, not nuclear. But I'll do my best.

Nuclear fuel isn't like a tank of gasoline, where it starts at "full", you drain it at a constant rate until it runs out, at which point it's "empty". It's an exponential decay process whereby the fuel's power gets smaller and smaller but never completely stops. At some point the primary fission fuel drops below what can be economically used in the reactor, at which point they remove the fuel.

But it's still experiencing fission decay, both from the low levels of U or Pt that remain, and from continued decay of the fission products that accumulated while the fuel was being consumed in the core (strontium, cesium, iodine, etc.) So ... the stuff is still quite dangerous (at first) and also still capable of producing heat. To deal with both these problems, they generally put the spent fuel in a "pool" (literally, it's filled with water) on-site, for some long period of time (months???) until the various radioisotopes have decayed still further. The water in the pool serves two purposes -- it keeps the spent fuel cool, and it blocks emission from the fuel rods.

The water needs to be actively circulated through the pool to dump off the waste heat. If this circulation stops, or the water is somehow removed, the spent fuel rods will begin to overheat. Their protective casing (cladding) can then be damaged. The worst-case scenario is that they get so hot that the cladding catches fire and bits of the still-radioactive fission decay products from the fuel rods are dispersed into the environment.

In the current situation, they're worried that the water in the spent fuel pools is boiling. If too much evaporates, the rods start to get exposed, and they can't lose heat efficiently, so they heat up further. Hopefully they can get cold water circulating through there ASAP. It's a bad sign that multiple SPFs are apparently heating up and they're talking about jury-rigged methods to get more water in -- dropping it from helicopters, sprayed from firehoses, etc. That's not going to work very long.

At least, that's my understanding. If someone here knows more about this, I'll happily defer to her/him.

narcoleptish wrote:
kurt_w wrote:
However, the heated water and steam also reacts with the zirconium in the cladding around the fuel rods, damaging the cladding and splitting the H2O, producing hydrogen gas, which accumulates at the top of the reactor building and eventually explodes in a dramatic PUFF!


Is a certain amount of hydrogen needed before it is combustible? Would some kind of a periodic ignition system be possible that would ignite the hydrogen in smaller, less damaging "puffs" in times of emergency such as this?


Yes, that's a very sensible idea. I recall reading some discussion of this and can't remember whether they have such a system, and if so why it's not working, or if they don't use something like this, what the reasoning is. Recall, though that the fundamental problem here was the loss of power from the diesel backup generators -- if there was an ignition system, maybe it doesn't function when there isn't external power to the plant (yes, believe it or not, these reactors that normally produce electricity do need to be receiving external power from the grid, generators, or batteries to function during an emergency).

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Re: SLEEP TIGHT TONIGHT

Postby Beaver » Tue Mar 15, 2011 1:43 pm

NIRS: Experts Warned in 1970s Against Fukushima-type Reactors
http://www.nirs.org/

"There are currently 23 General Electric Mark I reactors in the U.S.--the design that exploded at Fukushima. A top Atomic Energy Commission official first proposed banning this design nearly 40 years ago. Three critical Atomic Energy Commission memos on the GE Mark I reactor design:

November 11, 1971: outlines problems with the design and pressure suppression system containment.

September 20, 1971: memo from Steven Hanauer recommends that U.S. stop licensing reactors using pressure suppression system

September 25, 1972: memo from Joseph Hendrie (top safety official at AEC) agrees with recommendation but rejects it saying it "could well mean the end of nuclear power..."

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Re: SLEEP TIGHT TONIGHT

Postby kurt_w » Tue Mar 15, 2011 1:57 pm

Henry Vilas wrote:Sno, while we were told that those iodine pills were needed because we didn't eat enough seafood, they were for protection against the effects of radioactive fallout, not only from above ground testing, but also because of the threat of nuclear war during the 1950s.


Is that really true? Everything I've heard about the introduction of iodized salt only concerns the public health/iodine-deficiency issue. I don't think there's actually enough iodine in salt to protect children's thyroids from nuclear fallout. In the US, the big push for nationwide iodization of salt was in the 1920s, long before anyone had heard of nuclear fallout.

In countries like India where iodized salt wasn't widely used in the recent past, iodine deficiency has been a serious problem. For cultural, political, and economic reasons, there has been a great deal of resistance to iodizing salt in India, leading to entirely preventable, unnecessarily high levels of thyroid disorders and neurodevelopmental problems. Unfortunately, India is plagued with conspiracy theories about iodization -- see, for example, the psychotic websites claiming that iodized salt causes AIDS. (The US has no monopoly on lunatics, unfortunately....)

Note that in the US, before the introduction of iodization of salt, the Great Lakes states including Wisconsin had some of the worst levels of preventable mental retardation and hyperthyroidism.

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Re: SLEEP TIGHT TONIGHT

Postby Henry Vilas » Tue Mar 15, 2011 2:24 pm

"...children who had been given potassium iodide pills to prevent them from absorbing ... of radioactive fallout exposure in the United States during the 1950s..."

From The Thyroid Sourcebook for Women

I know this is not definitive proof, but a google search revealed similiar claims.

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Re: SLEEP TIGHT TONIGHT

Postby Endo Rockstar » Tue Mar 15, 2011 3:43 pm

The New York Times makes an info-graphic for dummies like me:
http://www.nytimes.com/interactive/2011 ... actor.html

-Dan Motor


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