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PostPosted: Mar 10, 2016 4:04 pm 
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I just saw an interesting article on the problems that they are having with robots becoming irradiated to the point that it destroys the electronics, rendering them quite literally dead in the water.

https://ca.news.yahoo.com/fukushimas-gr ... nance.html

I seems to me that the biggest problem is that they have an incredible amount of water that is contaminated with radioactive material. This water tends to leak from it's tanks and there is a threat of ground water seeping into the reactor site which would mean having to contain even more radioactive water.

A question I'd like to pose to the reader is, how can this radioactive water be best handled? What means could be employed to dispose of it, remove the radioactive material, or whatever might make this big problem much smaller?

One piece of information that would be helpful is knowing what isotopes are causing the radiation hazards, does anyone here know? If the isotopes are known then I suspect some chemical process could be employed to remove that element, then the now "clean" water could be then dumped into the ocean.

Personally I think the water should be dumped in the ocean anyway. The ocean is big and can take a huge radioactive load before anyone would even notice. I'm certain such a solution would bring all kinds of political resistance but as a matter of safety and logistics I'd think this is the best option. Don't dump it in all at once, or in one location. Get something like a large oil tanker, fill it with radioactive water and then go on an around the world cruise, slowly dumping the water along the way. When it's finished then fill it again and repeat until it's all gone. Is that such a bad idea?

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PostPosted: Mar 15, 2016 7:21 pm 
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Robots are indeed surprisingly intolerant of radiation. They can be designed to be shielded and use simpler more rad resistant electronics and sensors... but it takes a bit of money to do so. Using your off-the-shelf robot is not going to work well. NASA has spent a lot of money re-designing probes to survive the rads in space, going to places like the sun, jupiter, etc.

If the water is active enough to fail a robot by ionizing radiation then you'd have to clean it. Pretty simple - resin beds, and the like, can remove the fission products to acceptable levels.

One would not dump water with large amounts of fission products in it. The current considerations are to dump cleaned up water to the ocean. It has only tritium in it in trivial amounts, but somehow is causing a lot of fuss. Very odd since the water that is suggested to be 'dumped' complies with World Health Organization guidelines for drinking water - so considerably more "drinkable" than ocean water. Main reason is these are light water reactors that don't make much tritium in the first place. I would rather drink 10 liters of the water to be dumped than 10 liters of sea water myself, if given the choice. The LD50 of seawater is rather high - judging by the LD50 values, there's plenty of regular seawater to kill the world's population millions of times over. Of course that is quite silly but it is on the same vein of argument that is being used to prevent release of this WHO class drinking water to the oceans.


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PostPosted: Apr 02, 2016 3:55 am 
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Kurt Sellner wrote:
I seems to me that the biggest problem is that they have an incredible amount of water that is contaminated with radioactive material. This water tends to leak from it's tanks and there is a threat of ground water seeping into the reactor site which would mean having to contain even more radioactive water.

A question I'd like to pose to the reader is, how can this radioactive water be best handled? What means could be employed to dispose of it, remove the radioactive material, or whatever might make this big problem much smaller?
At this point, the water in all those tanks has been treated to remove all the isotopes disolved in the water. It is basically distilled water. There is effectively nothing in the water. The only issue now is that there is tritium as part of the water itself.

The IAEA has stated repeatedly that they should dilute the water to where the T concentration meets international standards and dump it. But the Japanese have been fear mongered for so long they would be needlessly terrified of that prospect.

My suggestion has been to take it to the arctic (or antarctic) and freeze it into a stable glacier until it is gone in about 120 years.

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PostPosted: Apr 02, 2016 3:59 am 
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Cyril R wrote:
Robots are indeed surprisingly intolerant of radiation.
NASA once bought a large number of 286 cores to have on hand because they had found that the features on that size die were radiation tolerant. The smaller the features, the less tolerant. Another lesson the Japanese have refused to learn?

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PostPosted: Apr 10, 2016 3:21 pm 
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Dear Kurt most of the water stored at the Fukushima site has a radioactivity of a couple of 100 Bq/L..not far away from drinking water. The sea contains about 70 bn tons of radioactive nuclides. If there is no additional serious chemical contamination it is the best to stop throwing away money and to dump it some 100 miles of the coast.

Best regards

Holger


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PostPosted: Apr 10, 2016 3:32 pm 
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The more interesting topic is the break down of the robots.

In the future in a MSR the primary circuit and the fuel treatment is due to the plating out of radioactive noble metals highly radioactive. If thorium is used in the fuel cycle there is as well the very hard gamma radiation from the decay of 232U.

The use of robots for maintenance and repair is a key to make internal fuel treatment and thorium feasible. It is as well an opportunity to make maintenance and repairs during the operation of such a reactor.

On the other hand electronic circuit becoming smaller and smaller and thus a few gammas or neutrons can put the electronics out of order. It is a very important matter to develop more resistant electronics for such a purpose.

Best regards

Holger


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PostPosted: Apr 10, 2016 7:27 pm 
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HolgerNarrog wrote:
If there is no additional serious chemical contamination it is the best to stop throwing away money and to dump it some 100 miles of the coast.


Perhaps you are correct in that the radiation is not as much of a hazard as the chemical composition. I have to wonder if it isn't a combination of the two. If the radiation takes the form of strontium, which the body can accumulate in bone, then that could be a problem. Naturally occurring radioactive isotopes that one might find in drinking water would be things like tritium and potassium, both of which will work their way out of the body in a few days like the very uncommon strontium.

I am reminded of an article I saw a few days ago. http://www.mirror.co.uk/news/world-news ... ng-7705006

Radioactive boars are finding shelter in the abandoned structures in the exclusion zone around the Fukushima power plant. With no predators to speak of, the meat being unsuitable for human consumption, and plenty of free space to roam, these boars are breeding like mad and will eat anything. Their diet will include the contaminated plant and animal life in the area.

Perhaps I do not understand the scale of the problem that the water poses. In that case I see no problem with dumping the water. At the same time I'd think that dumping the radioactive boars in the ocean should be acceptable.

I also believe that we should not get in the habit of just dumping radioactive waste into the ocean. We should treat this as an exceptional case.

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PostPosted: Apr 10, 2016 10:00 pm 
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Kurt Sellner wrote:
Radioactive boars are finding shelter in the abandoned structures in the exclusion zone around the Fukushima power plant. With no predators to speak of, the meat being unsuitable for human consumption, and plenty of free space to roam, these boars are breeding like mad and will eat anything. Their diet will include the contaminated plant and animal life in the area.

The boars are almost certainly only radioactive due to cesium. Te solution o that is take the boars to a feed yard. Feed them uncontaminated feed plus insoluble prussian blue for about 3 or 4 months. Slaughter and sell the meat.
Cesium doesn't bioaccumulate or concentrate, and iPB can reduce the bio halflife to about 20 days.

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PostPosted: Apr 11, 2016 3:14 am 
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KitemanSA wrote:
Kurt Sellner wrote:
Radioactive boars are finding shelter in the abandoned structures in the exclusion zone around the Fukushima power plant. With no predators to speak of, the meat being unsuitable for human consumption, and plenty of free space to roam, these boars are breeding like mad and will eat anything. Their diet will include the contaminated plant and animal life in the area.

The boars are almost certainly only radioactive due to cesium. Te solution o that is take the boars to a feed yard. Feed them uncontaminated feed plus insoluble prussian blue for about 3 or 4 months. Slaughter and sell the meat.
Cesium doesn't bioaccumulate or concentrate, and iPB can reduce the bio halflife to about 20 days.


Clearly you've never tried to catch a pig. I have, and it's not easy even for the more docile domesticate kinds I've dealt with.

Also, by decontaminating a boar in this manner you've merely moved the problem to disposing of the contaminated boar to that of handling the radioactive waste products the boars would produce.

What you propose sounds very expensive. Shooting the boars and disposing of the carcass seems simple and cheap by comparison.

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PostPosted: Apr 11, 2016 8:27 am 
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Wouldn't be easier to just keep the grass growing, strim it and store the strimmings?


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PostPosted: Apr 11, 2016 2:01 pm 
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Dear Both,

the radiation limit in Europa is a total contamination of 500 Bq/Kg of food. In Japan it is 100 Bq/Kg. The theorie in Europe is that a 75 Kg adult eats 1 Kg of this food/day (daily intake).

The equivalence dose for 137Cs is about 80000 Bq = 1m Sv radiation.

A dose of 100 m Sv/yr provides a statistical significant increase in cancer.

That means you can eat 16000 Kg of such boar/yr. to increase your probability of getting cancer significantly.

After Chernobyl my father gave a lot of presentations to hunters associations in Germany. We got some boar and deer....an enjoyed it.

Its a waste of food not to eat the boar.


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PostPosted: Apr 11, 2016 3:13 pm 
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HolgerNarrog wrote:
A dose of 100 m Sv/yr provides a statistical significant increase in cancer.

Ummm, no. A dose of 100mSv(acute) shows no detectible health effect. It takes at least 250mSv/a to reach the NOAEL (No Observable Adverse Effect Level). Some say 500mSv/a.

http://radiationeffects.org
http://dose-response.org

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PostPosted: Apr 12, 2016 11:51 am 
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Then you can eat the Fuskushima boar with more pleasure.

Holger


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PostPosted: Apr 12, 2016 1:21 pm 
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HolgerNarrog wrote:
Then you can eat the Fuskushima boar with more pleasure.

Holger

Even if we can assume the radioactive isotopes that are present in the meat pose no threat there are still other things to consider.

One example of a possible health risk is parasites. I had a raccoon problem a few years ago and one of my co-workers made something of a big deal out of a local group that had an annual turkey and raccoon dinner. I thought that if people around here eat raccoon then perhaps if I'm going to dispose of these raccoons anyway then perhaps I can get some meat from them. When reading up on the proper preparation of raccoons I saw numerous warnings about how to properly handle the meat so as to not to potentially get infected with a certain kind of parasite that raccoons are known to commonly carry. I read in several places that I should simply not bother.

Another example is what I heard of bear hunting. The phrase "you are what you eat" also applies to every other creature. People will look for bears in places with plenty of berries for them to eat. A bear that has a diet with plenty of sweet berries in their diet will have a much better taste than bears that can only find fish to eat. Bears are also like pigs in that they will eat many things that perhaps they should not, like poisonous berries, trash, and other things that can make their meat unpleasant or even dangerous.

Boars that crawl around in trash for food are likely to be dangerous to eat because of the parasites and diseases they pick up. Even if they are safe to eat because they were butchered and cooked properly then it's quite likely they won't taste very good.

I think it is wise to just kill them and burn the carcass.

I seem to recall that in Germany they also have a radioactive boar problem because of Chernobyl. It got so bad that no one wanted to hunt them. Without hunting the population grew to very problematic levels. The way the government addressed this is to require all boars killed to be tested, if the meat tested too high in radiation then the government would buy the boar and dispose of it. This way the public knew they would have safe meat and the government could control the boar population with minimal cost.

Looking at the article again it does not look like Japan does anything similar. It says they offer rewards for culling the boars but if they cannot harvest the meat then I'd think only the farmers seeing damage to their crops would have much of an incentive.

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PostPosted: Apr 14, 2016 2:56 pm 
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Hi Kurt,

there are of course plenty of green communists in Germany and a government that follows a strange ideology but..

"I seem to recall that in Germany they also have a radioactive boar problem because of Chernobyl. It got so bad that no one wanted to hunt them. Without hunting the population grew to very problematic levels."

There was plenty of things in the media. In some parts of Germany the radioactivity was in the years after chernobyl above the limits but hunters are in average more conservative than the average population. I assume that most of them made their hunting.


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