Effects of radiation on water

[SpliFF]

I assume there aren't any nuclear physicists around here but I can't be bothered registering to ask anywhere more appropriate. Maybe somebody has read something.

I have a question about the seawater cooling the damaged reactors in Japan. Assuming (and I know it's unknown at this time) that the fuel has melted and the containment vessel isn't watertight what would be the effect of contact between seawater and Uranium and/or MoX?

Obviously there'll be a lot of steam and presumably the steam will be radioactive but can it carry the fuel with it? What sort of transformations would happen within the steam/water itself. How long would it remain radioactive and what effect would it have on humans?

Does the water that doesn't escape as steam simply get pumped into the sea?

Given that that TEPCO and the Jap government began by saying everything was fine and every statement since has been followed by something exploding or another 10km being added to the "safe" zone I'm only interested in answers where it is assumed containment has been breached and that official comments are completely meaningless (ie, worst case).

[yuritch]

The water will surely carry some radioactive stuff in it. At least that's what happened during Chernobyl disaster.

Steam is likely to carry small bits of radioactive materials higher into the athmosphere (where they will be carried by winds to great distances), and water will have some of those dissolved and suspended in it (if that water gets back into the ocean that is).

Uranium is likely not the worst of that stuff - it's active isotopes are relatively short-lived. Cesium-137 and strontium-90 would be worse as they tend to accumulate in organic matter (strontium replaces calcium in bones for ex.) and their half-lives are about 30 years, so nearby sea life will be contaminated for a long time.

[SwiftSpear]

I can't give you a worst case scenario, but I can tell you that flooding the coolant chambers with sea water is the correct course of action. Cooling down the coolant rods is by far the best chance of preventing the worst case scenario, and the only accepted method of doing that is watercooling.

I do know that the explosions that have already occurred are caused by superheated steam separating into hydrogen and oxygen by radiation, and then being ignited by high temperatures.

I've read that the Japanese reactors, in the case of a worst case melt down, are designed to fail less dangerously than Chernobyl did. I've also read by some experts on the subject that that photo of horrendous lethal radiation bathing the west coast of the USA is entirely fear-mongering and not at all based on fact. What exactly could be expected in a legitimate worst case scenario though, I'm not sure.

[knorke]

the only accepted method of doing that is watercooling.

After a while the pressure inside becomes too high to pump in more water. So they have to let off steam/pressure which leaks radiation.

[SinbadEV]

the only accepted method of doing that is watercooling.

After a while the pressure inside becomes too high to pump in more water. So they have to let off steam/pressure which leaks radiation.

Water itself can't be radioactive but heavy water is still really bad for you... mind you there's probably lot's of radioactive particulate.

Guy at work says we should dump a couple tons of gold on it which would melt, coat the reactive materials and then block further reaction... would this work?

[smoth]

dihydrogen monoxide is serious shit man and is used in those japanese reactors.

[knorke]

sea water is not heavy water.
Using heavy water to cool would be stupid: It is usually used as moderator because it slows down neutrons (needed for chain reaction) but absorbs less neutrons then ie regular water. Absorbed neutrons are no longer avaivable for the reaction. So for cooling you want regular water or even something like boric acid, stuff that cools and also absorbs neutrons.

really bad for you

Toxicity in humans
Because it would take a very large amount of heavy water to replace 25% to 50% of a human being's body water (which in turn is 70% of body weight) with heavy water, accidental or intentional poisoning with heavy water is unlikely to the point of practical disregard.

dump a couple tons of gold on it which would melt, coat the reactive materials and then block further reaction

Not sure, but isnt gold able to change into a radioactive isotope? I think there are/were plans to increase the fallout of nuclear bombs by putting gold or cobalt inside. Don't know if that applies to power plants or only bombs. Also the fuel/fuel rods might melt into one clump and still produce heat, dunno if gold could transport that away.

[Licho]

Yeah both Chernobyl and recent Fukushima explosions were caused by dihydrogen monoxide!

Support ban of DHMO today!
http://www.dhmo.org/

[knorke]

that shit has been found in thousands years old ice samples at the poles, its not man made.

[SinbadEV]

sea water is not heavy water.
Using heavy water to cool would be stupid: It is usually used as moderator because it slows down neutrons (needed for chain reaction) but absorbs less neutrons then ie regular water. Absorbed neutrons are no longer avaivable for the reaction. So for cooling you want regular water or even something like boric acid, stuff that cools and also absorbs neutrons.

really bad for you

Toxicity in humans
Because it would take a very large amount of heavy water to replace 25% to 50% of a human being's body water (which in turn is 70% of body weight) with heavy water, accidental or intentional poisoning with heavy water is unlikely to the point of practical disregard.

dump a couple tons of gold on it which would melt, coat the reactive materials and then block further reaction

Not sure, but isnt gold able to change into a radioactive isotope? I think there are/were plans to increase the fallout of nuclear bombs by putting gold or cobalt inside. Don't know if that applies to power plants or only bombs. Also the fuel/fuel rods might melt into one clump and still produce heat, dunno if gold could transport that away.

Sorry, I was heavily misinformed and retract my prior statement... I though Heavy Water was caused by regular water being ionized by being bombarded by neutrons (similar to the production of uranium-235 isotopes from uranium-238 by neutron bombardment... sorry).

[dizekat]

sea water is not heavy water.
Using heavy water to cool would be stupid: It is usually used as moderator because it slows down neutrons (needed for chain reaction) but absorbs less neutrons then ie regular water. Absorbed neutrons are no longer avaivable for the reaction. So for cooling you want regular water or even something like boric acid, stuff that cools and also absorbs neutrons.

really bad for you

Toxicity in humans
Because it would take a very large amount of heavy water to replace 25% to 50% of a human being's body water (which in turn is 70% of body weight) with heavy water, accidental or intentional poisoning with heavy water is unlikely to the point of practical disregard.

dump a couple tons of gold on it which would melt, coat the reactive materials and then block further reaction

Not sure, but isnt gold able to change into a radioactive isotope? I think there are/were plans to increase the fallout of nuclear bombs by putting gold or cobalt inside. Don't know if that applies to power plants or only bombs. Also the fuel/fuel rods might melt into one clump and still produce heat, dunno if gold could transport that away.

Sorry, I was heavily misinformed and retract my prior statement... I though Heavy Water was caused by regular water being ionized by being bombarded by neutrons (similar to the production of uranium-235 isotopes from uranium-238 by neutron bombardment... sorry).

what you can get (a little) is tritium, which is nasty because you can't detect it with garden variety geiger counters (due to it's beta radiation having low penetration depth), all while it is as bad as anything else if irradiating you from inside.
I'd be more concerned about salts in the water, and them absorbing neutrons. I don't know from top of the head what radioactive isotopes can be formed from seawater, and it's a lot of elements so it's a major pain to look through them all on wiki.

[Cheesecan]

Probably a literal drop in the water compared to the likes of this.

[SwiftSpear]

The seawater is flushed back into the sea after it's done (assuming there isn't a total meltdown) so the small level of radioactive corruption it receives is diluted millions of times within the first few days.

The steam is undoubtedly dangerous, but there's not enough of it compared to a full reactor meltdown to cause serious harm far outside of the evacuation zone.


I thought this was cute :)

[Cheesecan]

The seawater is flushed back into the sea after it's done (assuming there isn't a total meltdown) so the small level of radioactive corruption it receives is diluted millions of times within the first few days.

The steam is undoubtedly dangerous, but there's not enough of it compared to a full reactor meltdown to cause serious harm far outside of the evacuation zone.


I thought this was cute :)

Um the core of reactor 1 is partially exposed.

What astonishes me is that they did not plan how to run the pumps when the electricity grid dies. Human error is always the biggest problem.

[SinbadEV]

The seawater is flushed back into the sea after it's done (assuming there isn't a total meltdown) so the small level of radioactive corruption it receives is diluted millions of times within the first few days.

The steam is undoubtedly dangerous, but there's not enough of it compared to a full reactor meltdown to cause serious harm far outside of the evacuation zone.


I thought this was cute :)

Um the core of reactor 1 is partially exposed.

What astonishes me is that they did not plan how to run the pumps when the electricity grid dies. Human error is always the biggest problem.

I think the point is that it survived multiple catastrophic failures in multiple redundancies which was significantly more then has been needed to set off meltdowns in the past (usually human error or poor maintenance of simple things like valves).

[PicassoCT]

There were diesel-generators there, but they got flooded. They bridged with batterys.. but those were just for minutes. What i dont get is - why build the reactors on land at all? Why not just a enterprise-carrier sized powerplant offshore?

And why not have robots start digging beneath the molten cores, to install catches? Oh, wait there was a tsunami, everything is in ruins, ups, nearly forgot that.

[SinbadEV]

What i dont get is - why build the reactors on land at all? Why not just a enterprise-carrier sized powerplant offshore?

Would be difficult to get the wires to the mainland grid I imagine...

[PicassoCT]

Like we have difficulties with underseaoilpipelines. And never forget, we could get in difficulties. Electrically charged water.

[BaNa]

http://mitnse.com/

this is a pretty good review of the situation imo, coming from good people. scroll down for the essay that details how the plant works.

[Sucky_Lord]

Im not an expert but im pretty sure the water vapour can't 'carry radioactivity'. Only things that are radioactive can give off radiation, bringing something into contact with radiation does not make it radioactive.