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UC San Diego researchers concluded that 400 billion neutrons were released per square meter surface of the cooling pools at Fukushima Daiichi

The 9.0-magnitude earthquake that shook Japan and crippled the reactor at Fukushima Daiichi nuclear plant back in March caused quite a bit of havoc with the release of radioactive water, contamination of crops and of course, the thousands of lives lost. At the same time, news networks like CNN and MSNBC sensationalized reports, causing unnecessary nuclear-related fear. U.S. senators even demanded the Nuclear Regulatory Commission to repeat an expensive inspection of U.S. nuclear plants.

In an attempt to clear some confusion and understand exactly how much radiation actually leaked from the damaged nuclear reactor at the Fukushima Daiichi nuclear plant in Japan on March 11, atmospheric chemists at the University of California, San Diego, have produced the first quantitative estimate of how much radiation actually leaked from the reactor.

Mark Thiemens, study leader and Dean of the Division of Physical Sciences at UC San Diego, along with post-doctoral researcher Antra Priyadarshi, and a team of researchers, observed the amount of radioactive sulfur in the air soon after the earthquake in Japan and was able to report a quantitative measurement of the amount of radiation leaked.

When fuel rods melt, products like neutrons leak from the fuel rods. Seawater is used to cool the hot reactors, and absorbs the leaked neutrons. These neutrons "collide" with chloride ions in the seawater, which results in the loss of a proton out of the nucleus of a chloride atom and turns the atom into a radioactive form of sulfur. Most of this vaporizes into steam when the saltwater comes into contact with the hot reactors, and to avoid explosions due to the collection of hydrogen, operators vent the steam into the atmosphere. Once in the air, the sulfur reacts with oxygen to create sulfur dioxide gas and eventually sulfate particles.

On the other side of the Pacific Ocean in La Jolla, California on March 28, 2011, Thiemens and his team noticed an "unprecedented spike" in radioactive sulfur in the air. They used a model, which was based on the NOAA's observations of atmospheric conditions, to determine the path the air took to get to California over the previous 10 days, and found that it had come from Fukushima Daiichi.

The next step was to calculate how much radiation had leaked from the reactor based on the path over the Pacific Ocean. They took into account that some sulfate particles had fallen into the ocean or decayed along the way, and concluded that 400 billion neutrons were released per square meter surface of the cooling pools. They predicted that this occurred between March 13, 2011 and March 20, 2011. March 13 was when operators began flooding the reactor with seawater.

"You know how much seawater they used, how far neutrons will penetrate into the seawater and the size of the chloride ion," said Priyadarshi. "From that, you can calculate how many neutrons must have reacted with chlorine to make radioactive sulfur."

To achieve the levels observed in California, the team said the concentrations a kilometer above the ocean close to Fukushima must have been 365 times above normal levels. Over the four days that the team took measurements, which ended March 28, Thiemens measured 1501 atoms of radioactive sulfur in sulfate particles per cubic meter of air. They mentioned that this was the highest they had seen in two years of observations and recordings.

According to the researchers, the radioactive sulfur observed was produced by partially melted nuclear fuel in the storage ponds or reactors. While cosmic rays can produce radioactive sulfur, the team noted that these rays rarely mix into the layer of air right above the ocean.

Despite the high levels of radioactive sulfur recorded in California, Thiemens and his team said these levels were not dangerous to human health.

"Although the spike that we measured was very high compared to background levels of radioactive sulfur, the absolute amount of radiation that reached California was small," said Thiemens. "The levels we recorded aren't a concern for human health. In fact, it took sensitive instruments, measuring radioactive decay for hours after lengthy collection of the particles, to precisely measure the amount of radiation."

This study was published in Proceedings of the National Academy of Sciences.

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Way to not give out info
By Dr of crap on 8/16/2011 1:03:17 PM , Rating: 3
"They took into account that some sulfate particles had fallen into the ocean or decayed along the way, and concluded that 400 billion neutrons were released per square meter surface of the cooling pools"

Why not give the explaination in the begining that this translates into nothing to be concerned about.

"First we'll scare them with the 400 billion figure, and only at the end will we say what that number means - he he he!"

Once again bad news reproting.

RE: Way to not give out info
By Flunk on 8/16/2011 1:28:13 PM , Rating: 2
Then you wouldn't have read the rest of the article of course.

RE: Way to not give out info
By FITCamaro on 8/16/2011 2:26:02 PM , Rating: 2
You can guarantee the major media outlets will seize on this report as well and will, at most, casually mention at the end that what it ACTUALLY means is nothing.

RE: Way to not give out info
By Dr of crap on 8/16/2011 3:36:38 PM , Rating: 2
Well absolutly.

That's what they do best now.

It's the scare the sh&t out of the viewers first, then tell the real story way of telling the news.

And the best part - there will be those "fringe" people that will get others to join them in believing that the sky is falling in on them and get some damn law passed about protecting EVERYONE from the fallout!

RE: Way to not give out info
By sleepeeg3 on 8/16/2011 8:00:20 PM , Rating: 2
There was already an article on this on SciAm yesterday:

End of long-winded article: "The chemicals posed 'no risk'"

At least their front page properly lists their bias:
"Science Agenda "

By MrBlastman on 8/16/2011 12:35:07 PM , Rating: 5
*psst* "Hey, over here!" "Mans, I gots a deal for ya," the sinister guy in a trenchcoat interwoven with lead paneling said in a quiet tone.

"I gots 3.9212 x10^-13 Kilos of Neutrons for ya! It's the stufffffffffff!" "Here, try it out yourself man, I just cut it," he said as he pulled back the leaded curtains, filling the alley with a green glow.

While it might seem like a lot (400 billion neutrons per sq. meter seems massive), it really isn't. Through some common internet diagrams, photos, I figure the pools were about 30 feet by 30 feet on average and they had 7 pools. The atomic mass of a neutron is 1.6749 x 10-27 kg. We're given that there are 400 billion neutrons released per square meter so with those facts and a little imperial to metric conversion, we can come up with absurd figures like the neutron dealer did above. (I'm such a nerd I computed it).

So, all I have to say for now is... *yawn* It might be a kinda cool experiment for my 18 month old to learn how to use a geiger counter on her bananas; though, her efforts might be fruitless, ha ha ha. Nothing to see here, move along everybody.

By Samus on 8/17/2011 12:52:34 AM , Rating: 2
Blastman smokes mad chronic.

By 0ldman on 8/17/2011 7:43:40 AM , Rating: 2
I'd give you a six if I could.


By Frank Truth on 8/16/11, Rating: 0
RE: Sensationalized?
By MindParadox on 8/16/2011 2:52:20 PM , Rating: 2
Over 10,000 people died in the Chernobyl disaster. Several hundred died within the first month. But several hundred thousand people were exposed to deadly levels of raditation.

get yer fact straight, moron

The Chernobyl accident in 1986 was the result of a flawed reactor design that was operated with inadequately trained personnel.
The resulting steam explosion and fires released at least 5% of the radioactive reactor core into the atmosphere and downwind.
Two Chernobyl plant workers died on the night of the accident, and a further 28 people died within a few weeks as a result of acute radiation poisoning.
UNSCEAR says that apart from increased thyroid cancers, "there is no evidence of a major public health impact attributable to radiation exposure 20 years after the accident."
Resettlement of areas from which people were relocated is ongoing.

next yer gonna tell us about the millions who died because of 3 mile island, right?
(link to page from where the above quote was taken)

The accident occurred in the very early morning of 26 April 1986 when operators ran a test on an electric control system of unit 4. The accident happened because of a combination of basic engineering deficiencies in the reactor and faulty actions of the operators. The safety systems had been switched off, and the reactor was being operated under improper, unstable conditions, a situation which allowed an uncontrollable power surge to occur. This power surge caused the nuclear fuel to overheat and led to a series of steam explosions that severely damaged the reactor building and completely destroyed the unit 4 reactor.

the link to that page (more specifically, the page denoting deaths attributed, and some facts concerning chernobyl and the surrounding regions)

RE: Sensationalized?
By bh192012 on 8/16/2011 6:33:45 PM , Rating: 4
Well since "There is no safe level of radiation" I suggest we move the earth as far away from the sun as possible. It is by far the most radioactive thing in our solar system and we must get as far away from it as possible ASAP. Unless we can devise some way to extinguish this runaway radioactive catastrophy!

Plants are also not safe, as radiation will also harm them, move all of your plants to a safe dark place, shielded from the sun.

Also, there are 200,000 disentigrations of Potassium-40 per minute in your children. 10% of this radiation is in the form of gamma rays! So make sure you douse your children in sea water whenever you see them.

RE: Sensationalized?
By goodsyntax on 8/17/2011 10:08:33 AM , Rating: 2
You should get your facts straight before you spout off like this.

- Nuclear power has one of the lowest total death rates of any power generation method (Reference:

- Radiation comes in numerous forms, some, such as Alpha radiation can't even penetrate a sheet of paper. Others are only dangerous if ingested.

- There is a branch of healthcare (Nuclear Medicine) which utilizes and introduces radiation into the human body for the treatment, imaging and diagnosis of numerous ailments. This is certainly not dangerous, and much to the contrary has saved countless lives.

- Radiation occurs naturally and is everywhere, from cosmic rays, to natural sources like C-14 (which is used in radio-carbon dating), K-40 (or potassium, which is found in many foods), Radon Gas (another naturally occurring source). In fact, a nuclear fission reaction occurred naturally in Oklo, Gabon, Africa 1.5 billion years ago - long before men and their evil nuclear reactors.

- Coal based power plants release more radioactivity into the atmosphere than nuclear power plants, especially older ones that do not have an effective fly ash recapture program.

- Fly ash (a byproduct of coal based power plants) is a major contributor of background radiation exposure to humans and is currently a major source material for sheet rock production.

Finally, how do you propose generating over 84,000 MegaWatts per day to replace the capacity generated at all US nuclear power plants?

- Are you willing to dedicate an area of 300 square miles to wind turbines for each nuclear reactor site you want to replace?

- Maybe you are willing to sacrifice 200 square miles to solar farms for each nuclear reactor site?

The fact is that the energy density in a nuclear powerplant is unrivaled. A nuclear site encompassing about 7 square miles produces the same energy output as hundreds of square miles of alternative energy sources. Add in the fact that high voltage transmission infrastructure is already in place at these sites and the alternatives do not, makes the decommissioning all nuclear powerplants an expensive proposition monetarily and ecologically as well.

Finally, I'm not sure where you get your facts regarding death rates due to Nuclear power. The fact is that the safety records at nuclear powerplants are unrivaled, even given Chernobyl and Fukushima. Consider for a moment that not a single nuclear powerplant worker has died in any of the 104 nuclear sites, spread over 40 years of service. More people have died from dog bites this year alone than in the entire history of US nuclear power.

Just some food for thought...

Math and basic chemistry
By monitorjbl on 8/16/2011 5:12:26 PM , Rating: 3
Ideal gas law: PV = nRT

P = the pressure of the gas (air at sea level, 101.325 kPa)
V = the volume of the gas (1 cubic Meter)
n = the number of moles of a gas (what I'm trying to find)
R = the gas constant (8.314 J·K-1·mol-1)
T = the temperature (30 C)
6.022x10^23 = number of atoms in a mole of a substance

This is an approximation because air is a mixture of gases, not pure. Anyway, there are .04 moles of air in a cubic meter, which means there are 2.41x10^21 atoms in that cubic meter. The source said there are 1501 radioactive particles (or as they are more colloquially known, "Scary Al-Qaeda Death Particles") in that cubic meter. To put this in more visual terms:

_________ 1501 _________ = 6x10^-18 % of the air

Frankly, I'm terrified.

RE: Math and basic chemistry
By sleepeeg3 on 8/17/2011 7:19:00 AM , Rating: 2
I would rate you up, but... oh wait... @#$%it!

By sleepeeg3 on 8/16/2011 7:40:38 PM , Rating: 2
One problem for another
By Paj on 8/17/2011 8:17:12 AM , Rating: 2
Its great that theyre releasing sulfur containing compounds into the atmosphere.

By fteoath64 on 8/20/2011 4:30:01 AM , Rating: 1
Not a single sesmic meter reading registers more than 6.7 magnitude. Also, if an 8.0 really hit, the skyscrapers will be falling down like dominoes. Was there a single tall building over 10 floors that fell over then ?. None! Nada, Zilch!. So quit spreading lies like CNN etc.

By boobo on 8/16/2011 3:51:46 PM , Rating: 2
2: We KNOW there is NO SAFE AMOUNT of radiation exposure. If you could eliminate it completely, you'd be better off.

I thought that if we eliminated all radiation completely, we would instantly freeze to death... no?

By MrTeal on 8/16/2011 4:08:39 PM , Rating: 2
Well, not instantly.

By letmepicyou on 8/16/2011 4:10:01 PM , Rating: 1
When posting at a site called "dailytech", one could hope for a modicum of intelligence in the posts. To infer that no one here knows the difference between the infrared radiation from the sun which provides our planet with heat, and ionizing radiation from beta and gamma sources locally within our environment, is ludicrous. If this is some kind of "joke", it's a poor one.

By Master Kenobi on 8/16/2011 7:05:22 PM , Rating: 2
The average DailyTech poster would most likely know the difference and it goes without saying. However, there are plenty of exceptions to that rule. The internet is a strange and terrifying place filled with people that probably shouldn't be allowed to exist, let alone vote and drive. All those warnings about thing not to do with a product came from people doing exactly that and someone sued over it. Just think, since the late 90's and early 00's all of those people are now on the internet posting stuff on websites just like this one. Scary shit isnt it?

By Dr of crap on 8/17/2011 8:54:28 AM , Rating: 2
And the problem that you list is -

They Do vote,
and they DO drive,
and they DO expect things to be handed to them and not work for them. And our society just caters to these people and doesn't stand up to them, and tell them NO.

By FITCamaro on 8/16/2011 7:41:51 PM , Rating: 1
If you eliminated all radiation other than output from the sun, you wouldn't know.

Why? Because it doesn't affect you in small amounts. The skin absorbs most of it.

By Hieyeck on 8/19/2011 11:51:03 AM , Rating: 2
Go Google the radioactivity of coal ash, a byproduct of burning coal for power.

Also bananas. Do us all a favor and stay away from your grocery store and starve.

By sleepeeg3 on 8/16/2011 7:41:41 PM , Rating: 2
More truth speak...
"these levels were not dangerous to human health"
All you need to know.

By zozzlhandler on 8/16/2011 8:23:12 PM , Rating: 3
Its not what you don't know that gets you, its the things you do know that just aint so.

I would not be nearly so sure that no radiation is healthy. There is evidence that a small level of radiation is beneficial to health. This would certainly make sense from an evolutionary point of view, since we evolved in a medium that included radiation.

By nmrahde on 8/17/2011 8:43:45 PM , Rating: 2
Some radiation is not just healthy, it's damn near necessary.

Our skin uses UV radiation to manufacture Vitamin D. There's actually a bunch of recent studies claiming that kids aren't getting ENOUGH radiation as nobody goes outside anymore.

Granted in a higher dose it can and will kill you. However this is true for pretty much everything from water to a 57 Studebaker.

Interesting side note for those not in the know - did you know the human body is naturally radioactive itself? Most of this comes from Potassium-40 (if I recall correctly). Apparently Potassium sometimes breaks down into this radioactive isotope.

Fun science experiment - fill your suitcase with bananas (or better yet, Brazil nuts) the next time you fly. The amount of Potassium-40 contained in a whole suitcase full should be enough to set off the airport's radiation detectors... :D

By Schrag4 on 8/17/2011 9:47:40 AM , Rating: 1
2: We KNOW there is NO SAFE AMOUNT of radiation exposure. If you could eliminate it completely, you'd be better off.

I'm not sure exactly what you mean by this. Since we all know that you cannot avoid radiation exposure, you must acknowledge that there's a certain level of radiation exposure that you personally will accept for yourself, right? Would you not get a chest x-ray or a CT-scan if your doctor said you needed one? Should women not get mammograms, especially those in families prone to breast cancer?

And if radiation exposure due to this accident turns out to be lower doses than these other forms of radiation that we willingly expose ourselves to, can't you see how this is a non-issue?

Or are you really, truely saying that you'd rather die of some undiagnosed illness than get an x-ray or CT-scan?

By nmrahde on 8/17/2011 9:03:36 PM , Rating: 1
Here's some more truth speak for you...

1. We KNOW radiation exists naturally. In all of us. Mostly in the form of Potassium-40.

2. We KNOW that UV radiation is necessary for the production of Vitamin D. If you could eliminate it completely you'd be like any number of fat kids who don't go outside anymore and have a Vitamin D deficiency.

3. Okay I don't really have an argument against this one.

As for the types of cancer increase from various sources, from what I understand there's a bit too many variables to make a simple chart for that. If you are truly concerned, stock up on iodine tablets. Your body will readily absorb iodine (radioactive or not) up to a certain point. If you're fully stocked on non-radioactive iodine your body will excrete the rest.

Many other radioactive materials aren't readily used in bodily processes so you only have to work about the radioactive particles themselves. Here what matters is the energy of the particle.

If I recall correctly (and I could easily be wrong lol) the heavier the particle the less energy it typically has. In most cases heavy alpha particles won't have enough energy to pierce the skin. Beta and gamma radiation have the potential to be more harmful as they can penetrate deeper.

------------------------------------------------- ----------
Perhaps more useful information for you (and all of us), would have been if the study provided the data in the form of Sieverts.

Straight from Wiki:
The sievert (symbol: Sv) is the International System of Units (SI) SI derived unit of dose equivalent radiation. It attempts to quantitatively evaluate the biological effects of ionizing radiation as opposed to the physical aspects, whichgray. are characterised by the absorbed dose, measured in that would have been far more useful in determining if this amount of radiation was actually harmful. It also would have been far less sensational.

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