backtop


Print 31 comment(s) - last by fteoath64.. on Aug 20 at 4:30 AM


  (Source: ibtimes.com)
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.


Comments     Threshold


This article is over a month old, voting and posting comments is disabled

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

...so 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.


"What would I do? I'd shut it down and give the money back to the shareholders." -- Michael Dell, after being asked what to do with Apple Computer in 1997














botimage
Copyright 2014 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki