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Filtering of Radioactive Water

04/06/2011 11:19 AM

What would state of the art filtration processeses accomplish with radioactive contaminated water?

Could the reverse osmosis process remove the salt and radioactive particles in order to allow the purified water to be returned to the storage pools? Obviously the prefilters, RO equipment and pumps would be heavily contaminated but it would be far better than dumping contaminated seawater into the ocean.

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#1

Re: Filtering of radioactive water

04/06/2011 12:02 PM

It all depends on what are the radioactive elements in the water. Every element on the periodic table has radioactive isotopes, some elements only exist as a radioactive isotope. So reverse osmosis should concentrate the radioactive salts and solids so that only water that might itself be radioactive (very unlikely) exists on one side.

Do we really want to concentrate the radioactive contaminants though. If you can control the contaminated water flow well enough that you capture it for reverse osmosis before it reaches the sea, then just stop the flow.

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#2

Re: Filtering of Radioactive Water

04/06/2011 12:33 PM

My understanding is that they need to remove the salt out of the water since it can accelerate the reaction not to mention corroding all of the equipment. They probably don't have multiple swimming pool size containers in order to process the water in the existing storage pools. Continuous filtering would potentially allow them to recirculate the water in the storage pools until the salt is removed. One line would run to the prefilters, then triplex pumps, RO bank and back to the storage pool(s).

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#3

Re: Filtering of Radioactive Water

04/06/2011 2:48 PM

Filtration and ion exchange resin can be used to remove radioactive contamination from water. Fission product gasses are not usually removed by these processes, but since those typically have short half lives and also may not stay in the water anyway, it isn't as big of a concern.

Fission product Radioisotopes which occur in the highest percentages, have high enough energy, long enough half lives, like cesium or rubidium and possibly special concern due to involvement biological processes, like iodine, as well as activated material with high energy decay and long half life, like cobalt 60, can all be effectively removed to purify the water....

The problem is one of having that equipment in place and having the time to do it. I'm certain every effort is being made to minimize the amount of radioactive material that reaches the sea. As i understand it, water with lower level radioactivity is being released to make room for more highly contaminated water.

None of this is good.

The news coverage is even worse and will damage the world for decades to come.

I doubt that the amount of radioactive material released so far or even after a protracted conclusion, will be anywhere near the equivolent of releasing 30 tons of uranium (plus much much more radioactive thorium) into the environment.

30 Tons of uranium is the average amount released to the environment every year by the average 1000megawatt coal plant. This would be a incrmdibly huge disaster in the nuclear power arena, but it is no accident with coal. It doesn't happen in obe plant in one country every twenty years, but at every coal plant reliably every year.

If you run in fear from nuclear power, like the drunk teen in every horror flick, you are not running to safety.

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#4

Re: Filtering of Radioactive Water

04/06/2011 3:38 PM

Any idea how much the background radiation level has increased due to human interaction? If we keep elevating the background levels and still use it as the "benchmark" for no harm to plant and animal life where does that leave us? It is all cumulative, food consumption, radon, background, flying at altitude, medical, or security scans...

Huge RO systems are in place in countries with a lack of fresh water. Navy ships have a substantial capacity to generate it. It would seem to make sense to put a kidney loop system in place to filter the storage pools on site provided portable systems are available.

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#5
In reply to #4

Re: Filtering of Radioactive Water

04/06/2011 3:47 PM

It depends on many variables on where you live and your lifestyle. You might want to try here to get a perspective.

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#14
In reply to #4

Re: Filtering of Radioactive Water

04/07/2011 5:59 AM

Here is some info related to increases in background radiation due to human activity.

http://www.ornl.gov/info/ornlreview/rev26-34/text/colmain.html

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#6

Re: Filtering of Radioactive Water

04/06/2011 4:08 PM

Good information. It just doesn't indicate how much the world wide background levels have changed since we started burning coal or introduced other sources that are now considered background radiation. Anyway this is getting off topic.

Anyone know why the RO systems are not being used? Is it because they can't get equipment in place or is there something wrong with the option of filtering the water on site?

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#8
In reply to #6

Re: Filtering of Radioactive Water

04/06/2011 4:37 PM

Frankly I think that they're a little too busy right now. The initial problem they were having was getting enough coolant of any grade where it was needed. This is why they choose to use sea water, it was plentiful and conveniently available. I'm sure they would've preferred having a vast quantity of distilled, salt free or boron salted water available when the temperatures started to climb. Instead of waiting for somebody to dismantle or take off the shelf a RO system that could fabricate a few million gallons of water, they wisely but reluctantly choose to pump seawater in. I'm also certain that nobody was happy to find out that the 9.0 earthquake had cracked some cement seals or whatever it was I saw gushing in a video.

Now that salt water has been used, I also think that using copious amounts of RO generated potable water to cool rods and a reactor that will never be used again is not a proper use of precious resources.

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#12
In reply to #8

Re: Filtering of Radioactive Water

04/06/2011 11:19 PM

Fred, that sort of rational, reasoned response has no place in the nuke debate.(GA)

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#7

Re: Filtering of Radioactive Water

04/06/2011 4:34 PM

There is an internet site, easily discovered, that tell me they have equipment that filters out arsenic, mercury, lead, bacteria and heavy metals, and is also able to filter out radioactive water contamination. The site is not heavy with content about how this is accomplished... I remain skeptical.

OK, we have figured out how to filter the water. Now, how about milk? More importantly, what about the beer?

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#10
In reply to #7

Re: Filtering of Radioactive Water

04/06/2011 10:51 PM

The only thing filtering my beer is my liver. Cheers!

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#9

Re: Filtering of Radioactive Water

04/06/2011 6:49 PM

There appears to be a problem with the salt accumulation blocking the heat transfer and coolant flow to the fuel rods. The sooner they can flush the storage pools the better. Using outside RO water isn't the solution if you have to dump the seawater into the ocean to make room for it. Using a kidney loop would be a better solution.

Article describing 100 tons of salt accumulation:

http://www.joewein.net/blog/2011/03/27/fukushima-a-future-cast-in-concrete/

I ran a quick search to see what skid mounted RO systems are out there. This is a sampling:

Skid mounted RO systems up to 260,000 GPD:

http://www.raindancewatersystems.com/watertreatment.html

Emergency mobile trailer unit up to 40,000 GPD:

http://www.ampacpure.com/turnkey_reverse_osmosis_systems.html/emergency_mobile_trailer_water_treatment

Trailer unit up to 200 GPM:

http://www.water.siemens.com/en/services/mobileandtemporary/Pages/Mobile_Reverse_Osmosis_Trailers.aspx

300 GPM unit:

http://www.marlo-inc.com/download/com/pdf/1100w.pdf

100 Cubic meters/hour:

http://www.lenntech.com/systems/reverse-osmosis/ro/rosmosis.htm

100,000 GPD:

http://ampac1.com/skid-mount_ro.htm

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#11

Re: Filtering of Radioactive Water

04/06/2011 11:17 PM

Yes, of course they could. But dumping a small amount of contaminated water wont cause any problems either.

Use a sewage analogy, human poo is a potent source of e-coli. at a concentration of millions of times over the recommended drinking water limits, Grind it up and drop it the ocean and next day you wont be able to detect it.

There's a lot of anti nuclear hysteria out there, it important to keep things in perspective.

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#15
In reply to #11

Re: Filtering of Radioactive Water

04/07/2011 11:21 AM

Take your example and place it at a lake next to your beautiful new lake cottage. Consider the exclusion zone similar to the one in Japan. Should I care if the global net effect is inconsequential? How does proximity change your perspective?

The original purpose of my question was not how to clean up just the mildly radioactive water but all of it so you aren't faced with the choice of what to release into the environment.

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#16
In reply to #15

Re: Filtering of Radioactive Water

04/07/2011 12:03 PM

I understand the purpose of your question, you seem to be willingly misunderstanding the point of my answers. The operators at Fukushima are mitigating the problems as they understand them with what they actually have available not with what you think that they should have. The earthquake and tsunami combination exceeded the disaster preparation levels this facility anticipated. So many parts of the system that were intended to be activated in the event of a lesser disaster do not function for yet to be determined reasons. Before they can try to repair the facility, they are working on controlling the reactors and stored spent fuel rods with what they have available.

Now to get back to answering your initial question, concentrating the radioactive contaminants of the runoff coolant that is reaching the sea requires first collecting the runoff coolant. If any facility can successfully gather all of the runoff before it reaches the sea then returning any of the water back to the sea means that you have less coolant in the storage ponds and the reactor chamber. Instead of cleaning this contaminated water, send it back to where it can again cool.

Also, your idea will render a machine that can sustain human life in the middle of a disaster into a hazard concentrating device. That has to be an engineering sin.

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#17
In reply to #16

Re: Filtering of Radioactive Water

04/07/2011 1:33 PM

I've laid out a scenario using your example, considering the magnitude similar to the current situation (Exclusion zone). You can pick the hazardous waste, it doesn't have to be nuclear. Would your perspective change based on your proximity?

The question started with: Would filtering of radiactive water help this situation by removing the radioactive particles? I know it will remove the salt. The goal was to reduce the radioactive levels in the storage pools water, flush out the salt interfering with the cooling of the storage pools and accelerating the reaction. This proposal is describing a kidney loop system that has nothing to do with the leakage or runoff. That is another issue. The kidney loop if functional would have the added benefit of reducing the radioactive levels of any water escaping.

In regard to working with what they have... This isn't an Apollo 13 situation where you have to make do with what you have available. Likewise people outside the emergency zone can be sought to devise potential solutions.

Regarding the issue of highly contaminated RO equipment:

Yes, it would be highly contaminated containing the 100 tons or so of salt and radioactive particulate. Would it be better to have the RO equipment skid based and be able to dispose of it rather than using pumps and RO systems in the plant (If they can get them to work again).

What would you suggest doing with the heavily salt ladden water in the storage pools considering they still have to circulate water for cooling?

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#18
In reply to #17

Re: Filtering of Radioactive Water

04/07/2011 5:10 PM

You just seem to refuse to accept the situation, in many critical ways this is an Apollo 13 like scenario. Unlike Apollo 13, people can leave the area and small amounts of supplies can be brought in. Similar to Apollo 13, they cannot just stop all processes they have because something went wrong. Similar to Apollo 13, incidents happened that required immediate responses before things got worse. Similar to Apollo 13, we can only ascertain what is happening from looking at things from outside the incident. Now that the control room has power brought in to turn on the monitoring equipment, they do have a better picture of the conditions in the storage pools and the shutdown reactors. But several of the critical incidents at Fukushima (particularly the use of sea water) happened prior to having power in the control room. I find it insulting to imply that the Fukushima operators made the wrong choice to use sea water when they did.

Now many an irritating implication was simply a case of reading too much into a comment. I'll assume that I'm reading too much into your comment.

As far as the sea water in the pools, I'd leave it to engineers that know both the facility and the contaminants in the water to decide what to do. I don't know either of these critical concerns.

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#19
In reply to #18

Re: Filtering of Radioactive Water

04/07/2011 6:59 PM

That is the beauty of a kidney loop filtration system. It acts in parallel to current operations. Nothing would have to be shut down or disrupted. The technicians in the control room would be free to do what they need to do. This is provided you are using independent equipment and lines to the storage pools.

I find no fault and offer no criticism of their use of seawater in this emergency. It was the right thing to do at the time. I never implied that it was the wrong decision.

Is this an engineering forum or not to discuss possible solutions to difficult problems? If the last gulf oil spill was any example, leaving it to the experts didn't provide a very speedy solution. They can use all of the ideas available. They can weed out the ones that are not practical.

If you don't care to answer the question regarding your proximity to an equivalent hazardous waste scenario, I understand.

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#20
In reply to #19

Re: Filtering of Radioactive Water

04/07/2011 7:45 PM

I was really hoping that you could think a little bit more about what you are proposing.

Circulating the cooling water and concentrating the radioactive contaminants outside of the containment pool or reactor chamber will make things worse and not better. To propose doing anything with zircon encapsulated fuel rods, you should know the chemistry and physics why fuel rods are encapsulated in zircon. Uranium salts are water soluble. Most of the radioactive fission product salts are water soluble. Zircon is chemically stable in water and will not dissolve in water. The byproducts though are so radioactive that they need lots of water around them to shield the radiation they are releasing. So if the zircon cladding melts, the fission byproducts and uranium salts can now dissolve in water. Of course only once cooling water returns. When a pool gets refilled the radiation level outside of the pool will be higher than before even though the same average number of disintegrations per second is occurring. The radioactive salts dispersed in the water will just have less shielding to travel through. Circulating this cooling water into the Reverse Osmosis device will concentrate the radioactive elements in the device. The device does not have as much water shielding and cooling as the pool. Instead of containing a problem, you will be dispersing the problem to the Reverse Osmosis filters at higher concentrations than just letting the water overflow the pools.

Now can you see why this is a bad idea or do you prefer to still not think this through.

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#21
In reply to #20

Re: Filtering of Radioactive Water

04/07/2011 8:38 PM

Thanks for the information. I see in the following article that Japanese scientists tried to harvest uranium from sea water finding it technically feasible but the yield being too low "due to the carbonate present in the water". It is under the Resources and reserves section. What would be the potential of dusting off this experiment using additional feed water to the ion exchangers to limit uranium concentration to a safe working level?

http://en.wikipedia.org/wiki/Uranium

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#13

Re: Filtering of Radioactive Water

04/07/2011 12:12 AM
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#22

Re: Filtering of Radioactive Water

04/07/2011 9:30 PM

I ran a search based on the Wiki reference. It appears the main issue was the cost of extraction. Since uranium concentration is high in the storage pools it would make sense to dilute it during processing to a level you can safely manage.

http://dspace.mit.edu/bitstream/handle/1721.1/60556/EL_TR_1981_038.pdf?sequence=1

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