Discovery sheds light on nuclear reactor fuel behavior during a severe event

November 20, 2014
An Argonne-led research team found that when uranium dioxide melts, the number of oxygen atoms around uranium changes from eight-fold to a mixture of six- and sevenfold, which alters how it interacts with other materials. The discovery about will help scientists select the best computational model to use when simulating severe nuclear reactor accidents.

A new discovery about the atomic structure of uranium dioxide will help scientists select the best computational model to simulate severe nuclear reactor accidents.

Using the Advanced Photon Source (APS), a Department of Energy (DOE) Office of Science User Facility, researchers from DOE's Argonne National Laboratory and Brookhaven National Laboratory, along with Materials Development, Inc., Stony Brook University, and Carnegie Institution of Washington, found that the atomic structure of uranium dioxide (UO2) changes significantly when it melts.

UO2 is the primary fuel component in the majority of existing nuclear reactors, but little is known about the molten state because of its extremely high melting point. Until now, the extremely high temperature and chemical reactivity of the melt have hindered studies of molten UO2. This lack of fundamental information has made it difficult to evaluate issues associated with the interaction of molten UO2 with a reactor's zirconium cladding and steel containment vessel.

The research team found that when uranium dioxide melts, the number of oxygen atoms around uranium changes from eight-fold to a mixture of six- and seven-fold, which changes the way it interacts with other materials. Many existing models, however, do not account for this change in structure or the rapid oxygen dynamics that occur at high temperatures.

"Determining the behavior of UO2 under extreme conditions is essential to enhancing our understanding of reactor safety during severe accidents," said Mark Williamson of Argonne's Chemical Sciences and Engineering Division.

"Very few places in the world have the capability to safely measure the structure of molten UO2 at 3,000 degrees Celsius without introducing contamination from the container that holds the melt," added Chris Benmore of Argonne's X-ray Science Division.

Researchers studied the UO2 in the hot crystalline and molten states. In this experiment, researchers relied on the APS's high-energy synchrotron X-ray beam to study a bead of UO2 that was aerodynamically levitated on a stream of argon and heated with a laser beam.

X-ray experiments were performed at sector 11-ID-C at the APS.

The work was funded by the DOE Office of Science (Office of Basic Energy Sciences), the DOE Small Business Innovation Research program and the Argonne Laboratory Directed Research and Development program.

The paper, "Molten uranium dioxide structure and dynamics," is published in Science magazine.

"Our group plans to continue to use innovative synchrotron techniques to study molten materials like this," said John Parise, who holds a joint appointment with Brookhaven National Laboratory and Stony Brook University. "The next steps include putting molten materials under different atmospheres, and that requires modifications to the existing set-up used at APS."

Parise said this group of researchers, which includes colleagues from Materials Development, Inc., who built the apparatus used to study UO2, is discussing designs for next-generation levitation devices that could be installed at the X-Ray Powder Diffraction beamline at Brookhaven's National Synchrotron Light Source II, for example.

"There's a lot more work to be done," Parise said. "It's important to understand how many other materials behave in a molten state. Theory is a good way to do that, but theorists need data on how atoms interact with each other in the molten state, under conditions that are as realistic as possible."

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21 comments

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gkam
1.7 / 5 (11) Nov 20, 2014
Why don't those smart nuclear engineers just go get some of those three molten blobs that used to be reactors and hundreds of tons of fuel at Fukushima?
gkam
1.9 / 5 (9) Nov 20, 2014
Perhaps one of the three malcontents has an answer?
Da Schneib
5 / 5 (1) Nov 20, 2014
You gonna go in and get a sample?

gkam
1.9 / 5 (9) Nov 20, 2014
We do not even have robots which can. Nor vision devices which can survive the radiation environment.

We had several instances of Neutron flux, signifying a self-criticality in one of the units. Reporting negatively about Fukushima is against Japanese secrecy laws.
FredZ
not rated yet Nov 20, 2014
This is really nice work for fresh nuclear fuel. Unfortunately, burnup will change both the physical and chemical characteristics of the fuel. At 30,000 MWD/MTU, this research would not be very relevant.
Da Schneib
3 / 5 (4) Nov 20, 2014
Reporting negatively about Fukushima is against Japanese secrecy laws.
Don't lie or I'll put you on ignore.

You already got pwnt on this lie by Eikka (did I spell that right?).

This is really nice work for fresh nuclear fuel. Unfortunately, burnup will change both the physical and chemical characteristics of the fuel. At 30,000 MWD/MTU, this research would not be very relevant.
It's irrelevant what the chemical structure of the base material is?

Wow, you have a pretty bad relevancy-sniffer there, sport.

And there's plenty of spent fuel around for them to run the next experiment on.
FredZ
5 / 5 (3) Nov 20, 2014
I have a Ph.D. in nuclear engineering with emphasis in materials science, and about 40 years of experience in both Naval nuclear propulsion and commercial nuclear power plants. You should be more reluctant to put your profound ignorance on public display.
Da Schneib
3 / 5 (2) Nov 20, 2014
Bullshit. Good bye.
TheGhostofOtto1923
3.5 / 5 (8) Nov 20, 2014
Bullshit. Good bye.
Perhaps he does. Perhaps he was talking about the megacrank gkam and not you. Perhaps he would like to stick around and expose some of gkams megashit. Although it doesn't really take a phd to do this.
gkam
1.9 / 5 (9) Nov 20, 2014
Reporting negatively about Fukushima is against Japanese secrecy laws.

"Don't lie or I'll put you on ignore."
----------------------------------------------------

Before you go in your silly snit, let me give you some references.

http://www.reuter...20131025

http://www.npr.or...japanese

http://www.thegua...-secrets

http://www.theeco...own.html

https://blog.nade...america/

http://www.washin...ism.html

Those are just the first references listed. Want the rest? Go look.

Da Schneib
3.7 / 5 (3) Nov 20, 2014
None of them says anything about the Japanese actually restricting data about Fukushima.

Good bye, gkam. I don't consort with liars. I've been watching you for quite a while to see if you had integrity and you have totally failed.
gkam
1.9 / 5 (9) Nov 21, 2014
You are the big fibber. If you had read the articles you would have seen the headlines:
"Japan Reacts to Fukushima Crisis By Banning Journalism"

Your ignorance has caught up with you. Go to Fukushima Diary or EXSKF for some sensationalist but accurate reporting of what we can get from TEPCO and the government.

"Been watching me"? Oh, NO!!

Challenge me. Read the reports. Go look elsewhere than places to confirm your biases.
gkam
2 / 5 (8) Nov 21, 2014
http://www.indepe...296.html

There is some more integrity for you.
gkam
1.9 / 5 (9) Nov 21, 2014
And if you want to check some more, I specified some computer-operated IC testers we used in the early 1970's, which you can look up and challenge, in the Improving Flash Memory thread.

Come on by. But stop the character assassination.
Da Schneib
3.7 / 5 (3) Nov 21, 2014
Sorry, gkam, I don''t like anti-nuke cranks and liars any more than I like climate cranks and liars. You're doing a serious disservice to the cause of combating climate cranks by being a crank yourself. I don't like it, I don't approve, and I don't want to watch.

Good luck.
Eikka
4.5 / 5 (8) Nov 21, 2014
You are the big fibber. If you had read the articles you would have seen the headlines:
"Japan Reacts to Fukushima Crisis By Banning Journalism"


Sensational headlines are irrelevant.

Has Japan actually legislated against spreading information of Fukushima?

No.

Have they actually thrown journalists in jail and censored their output for giving out information about Fukushima?

No.

Would it make sense for them to do so amidst all the protest against the new laws?

No.

So you can now stop spreading your misinformation and actually have some integrity yourself.
Doug_Huffman
not rated yet Nov 21, 2014
[ ... ]You should be more reluctant to put your profound ignorance on public display.
LOL I saw the 'comments' number and couldn't imagine any good sense driving numbers like that. Tip o' the hat. Retired NS 0989-028-5000 test engineer.
Uncle Ira
4 / 5 (8) Nov 21, 2014
@ Obama-Socks-Skippy where you at Skippy?

Reporting negatively about Fukushima is against Japanese secrecy laws.

"Don't lie or I'll put you on ignore."
----------------------------------------------------

Before you go in your silly snit, let me give you some references.

http://www.reuter...20131025

Those are just the first references listed. Want the rest? Go look.



Well golly gee Cher. Since you've learned to put the linkums, why you don't put up some to prove about the the lies you was telling everybody to find some way to look up your lies?

You got the advantage on us Skippy. You just too smart for us.
TheGhostofOtto1923
3.7 / 5 (6) Nov 21, 2014
I suppose these have been posted before:
http://en.wikiped...recy_Law
http://www.npr.or...japanese

-NPR the quintessential liberal news source makes no mention of meltdowns re this law. Gkam/mother jones is on the rag again.
dtxx
5 / 5 (1) Nov 22, 2014
I suppose these have been posted before:
http://en.wikiped...recy_Law

-NPR the quintessential liberal news source makes no mention of meltdowns re this law. Gkam/mother jones is on the rag again.


He's double full of shit because none of the news sources he listed are from japan and thus would not be bound by japanese laws. He put the Guardian in that list for fuck's sake. That's the same paper that published all of the wikileaks stuff. If they will piss the US off that much, why would they give a shit about doing something minor to irritate Japan?
Da Schneib
1 / 5 (1) Nov 22, 2014
The Snowjob shot the Grauniad's cred for me. They went for the money, just like Greenwald was doing writing the crap in the first place.

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