Radiation leaks from Fukushima now “harmful” ["levels of up to 400 units of radiation an hour"]

Euro News ^ | 15/ 03 /11

[Double Tap]

Earlier I was seeing the microsievert unit used. Until we know what “unit” they are talking about we are just wild ass guessing unfortunately.

If they are indeed using millisieverts now, that is a whole nother can of poop.

[RummyChick]

YOu make it all sound so safe.
HOWEVER

lets point to a few things.

TEPCO lied and had to have all the plants closed down years ago.

It falsified safety tests on a containment vessel.

Is it true that this organization

http://www.icrp.org/

Has said that only 1 MG of Plutonium should be released from a MOX facility under safety guidelines verus 2 KG of uranium in an accidental release.

[RummyChick]

They are using millisieverts. Thus the no fly zone and the evacuation in a 20 kilometer radius last night.

400 MILLIESEVERTS outside of Reactor 3.

[RummyChick]

So let’s say the worst happens at Reactor 3.

No wind damage to California.

But plutonium has been released in Japan.

Why about radioactive materials coming from people and imports.

[chimera]

Believe what you want. I am only commenting about the technology as I know it. The source term for a LWR accident release contains very little of the native fuel material. Things like uranium and plutonium in the chemical and physical form they are in MOX or uranium fuel simply are not that mobile. They have a very high boiling point and so don't vaporize. They essentially stay in solid form and as such are not readily dispersed, like gases or liquids are.

And no, there is no comparison to Chornobil because LWR fuel, as we are seeing, does not undergo an explosive energy release. It is a slower process. Less energy, less dispersion. The explosions we have seen so far are most likely from a buildup of hydrogen gas. The explosive process is not within the fuel material.

[RummyChick]

You didn’t really answer my question.

We know that TEPCO has had issues about the safety of their containment vessels .

So, is this true:

http://www.icrp.org/

Have they said that only 1 MG of Plutonium should be released from a MOX facility under safety guidelines verus 2 KG of uranium in an accidental release.

[ScubieNuc]

It is important to remember that that chart is REMs per year. While the radiation measurements coming out last night was measured in per hour. And doses are cumulative. So while short exposures aren't dangerous you wouldn't want to work in a place where you were pulling 3 REM per hour.

Yes, that is a good point. I wasn't trying to minimize dose rates, but trying to give a scale on which people could estimate what the actual physical danger level might be.

For example, I know that in the nuclear industry, the NRC limits workers to no more then 5 Rem per year. If a person were to exceed that then you could see some kind of story along the lines of "Workers recieve excessive radiation doses". While it is true on one hand, the dose may have just been 7 Rem, in which case there was no real physical threat to the workers.

[GonzoGOP]

But plutonium has been released in Japan.
Why about radioactive materials coming from people and imports.

One thing about plutonium is that it tends to have very visible effects very quickly. PU-239 is an alpha emitter, so it has to get inside your body, but if you inhale or injest it you will start to show symptoms almost immediately.

The point is nobody should be tramping around an uncontained radioactive site to get this stuff on the feet.

[chimera]

I went to your ICRP link and didn't see any specific articles related to either the Japan situation, or LWR source terms. Is there a more specific link to what you wanted?

If anything, those numbers seem high to me. The ratio of Pu to U seems about right, at least in the ball park. Remember that we are only talking about 7% of the original material being Pu. That gets you an order of magnitude right off the bat. The difference in diffusion coefficients and mobility, plate-out rates and trapping mechanisms, probably gets you another 3 orders of magnitude. So you are down from KG to tens of milligrams. Without running the particular models, probably differences in dilution rates gives you another order of magnitude. So I can see how you'd probably get in the range of five orders of magnitude difference.

BTW, plutonium has been released in Japan before. The Nagasaki weapon dispersed kilograms quantities of material in the local area, and vaporized quite a lot (a weapon generates more heat than a core accident). Last I checked, they had cleaned up pretty well from an event infinitely worse than anything we'll see here:

[HereInTheHeartland]

“Four reactors at the plant have now exploded. “

No reactors have exploded.

[mrsmith]

"If they are indeed using millisieverts now"

They were using millisieverts last night.
The one 400 reading was unusual and may be an anomaly.
It dropped back into the micro range a few hours later.

This chart of the time around the fire is in micros:

[Captain Peter Blood]

I believe the Enviros, Left Wing idiots, etc., are fueling an hysteria that is not warranted by the facts.
It seems hard to get any kind of unbiased information on what is really going on.
Other reports I have seen indicate ,that while there are still major problems, there are no meltdowns and radioactive emissions are coming under control.

[silverleaf]

melted down reactor cores do not “blow up”
they melt down

The explosions you are seeing are coming from vented hydrogen and other gasses, they are not nuclear detonations

What is unclear from GOJ reports is how much radiation iis being intentionally vented with the gas buildups from each reactor to reduce pressures and heat, and how much is escaping uncontrolled (and to what extent) because the core containment vessel has been breached

In Chernobyl (not remotely similar deisgn) the core was exposed and vented into the atmosphere, less primitve designs are redundant to contain at least some (most) of the material from exposure and dangerous levels of radiation from escaping in large uncontrolled plumes (exposure radius and danger level unclear in this plant, tbd, controlled venting while undesirable is probably a long term project)

the radiation if released comes from steam and dust blown off the site, which to reach the USA would have to reach an altitude to be carried acorss the Pacific and then settle

If you want to be really really alarmed, just look at the USA death toll from Three Mile Island because it melted down right in the heart of the eastern seaboard

If there are true nuc engineers here maybe they can correct any misstatements here

[Hector_in_FL]

What happens when the spent fool pools dry up?

[gunsequalfreedom]

Thanks for the info. Had never seen that scale before.

[silverleaf]

well, I suppose when the material reaches a stage in its life when radioactivity levels allow the intervention of human technology, it will either be removed via dry storage containment, as it was when it was shipped there

or if not, they will figure out a way to prevent it from leeching into or migrating into the surrounding soil and groundwater (if that is an issue here) and encase and entomb it at the site -

more likely eventual removal given the seismic risks just guessing!