Purdue engineers create safer, more efficient nuclear fuel, model its performance

[K1052]

Purdue University nuclear engineers have developed an advanced nuclear fuel that could save millions of dollars annually by lasting longer and burning more efficiently than conventional fuels, and researchers also have created a mathematical model to further develop the technology.


New findings regarding the research will be detailed in a peer-reviewed paper to be presented on Oct. 6 during the 11th International Topical Meeting on Nuclear Reactor Thermal Hydraulics in Avignon, France. The paper was written by Shripad Revankar, an associate professor of nuclear engineering; former graduate student Ryan Latta, now an engineer at Brookhaven National Laboratory; and Alvin A. Solomon, a professor of nuclear engineering.

The research is funded by the U.S. Department of Energy and focuses on developing nuclear fuels that are better at conducting heat than conventional fuels. Current nuclear fuel is made of a material called uranium dioxide with a small percentage of a uranium isotope, called uranium-235, which is essential to induce the nuclear fission reactions inside current reactors.

"Although today's oxide fuels are very stable and safe, a major problem is that they do not conduct heat well, limiting the power and causing fuel pellets to crack and degrade prematurely, necessitating replacement before the fuel has been entirely used," Solomon said.

Purdue researchers, led by Solomon, have developed a process to mix the uranium oxide with a material called beryllium oxide. Pellets of uranium oxide are processed to be interlaced with beryllium oxide, or BeO, which conducts heat far more readily than the uranium dioxide.

This "skeleton" of beryllium oxide enables the nuclear fuel to conduct heat at least 50 percent better than conventional fuels.

"The beryllium oxide is like a heat pipe that sucks the heat out and helps to more efficiently cool the fuel pellet," Solomon said.

A mathematical model developed by Revankar and Latta has been shown to accurately predict the performance of the experimental fuel and will be used in future work to further develop the fuel, Revankar said.

Pellets of nuclear fuel are contained within the fuel rods of nuclear fission reactors. The pellets are surrounded by a metal tube, or "cladding," which prevents the escape of radioactive material.

Because uranium oxide does not conduct heat well, during a reactor's operation there is a large temperature difference between the center of the pellets and their surface, causing the center of the fuel pellets to become very hot. The heat must be constantly removed by a reactor cooling system because overheating could cause the fuel rods to melt, which could lead to a catastrophic nuclear accident and release of radiation ? the proverbial "meltdown."

"If you add this high-conductivity phase beryllium oxide, the thermal conductivity is increased by about 50 percent, so the difference in temperature from the center to the surface of these pellets turns out to be remarkably lower," Solomon said.

Revankar said the experimental fuel promises to be safer than conventional fuels, while lasting longer and potentially saving millions of dollars annually.

"We can actually enhance the performance of the fuel, especially during an accident, because this fuel heats up less than current fuel, which decreases the possibility of a catastrophic accident due to melting," Revankar said. "The experimental fuel also would not have to be replaced as often as the current fuel pellets.

"Currently, the nuclear fuel has to be replaced every three years or so because of the temperature-related degradation of the fuel, as well as consumption of the U-235. If the fuel can be left longer, there is more power produced and less waste generated. If you can operate at a lower temperature, you can use the fuel pellets for a longer time, burning up more of the fuel, which is very important from an economic point of view. Lower temperatures also means safer, more flexible reactor operation."

Solomon said a 50 percent increase in thermal conductivity represents a significant increase in performance for the 103 commercial nuclear reactors currently operating in the United States.

"Just a 5 to 10 percent increase would be pretty significant, so a 50 percent increase would be quite an improvement," Solomon said.

The next step in the research is to test the new fuel inside a nuclear reactor to make sure it stands up to the extreme conditions inside reactors over its entire lifetime.

"We know it holds up well to very high temperatures, and now we are at the point where we want to irradiate this material and see what it does," Solomon said.

The researchers also had created fuel pellets containing fingers of another high thermal conductivity material called silicon carbide, but the silicon carbide reacted with the uranium oxide at elevated temperatures. New fuel designs made of compatible uranium compounds are presently being studied. The research paper being discussed in October concentrates on the model's accuracy in predicting the results of experiments with silicon carbide and beryllium oxide, Revankar said.

Source: Purdue University

http://www.physorg.com/news6834.html


More power, less waste, better saftey, and longer between refueling outages. Looks like a win-win development all if it pans out as they expect it to.

 

[Future Shock]

GO PURDUE!!!

 

[Malfeas]

Wow, thanks for the link. I've been browsing through the headlines of all the articles. I can see myself spending quite a bit of time over the next few weeks reading all of those. Lots of cool stuff there.

P.S. I am not being sarcastic, that site really looks cool.

 

[2cpuminimum]

This sounds like a great advance, but wouldn't it be much better to start using breeder reactors? Why hasn't carter's 1977 decree not to use fast breeder reactors been repealed yet?

 

[Pabster]

FWIW, Purdue University was recently the subject of an investigation into security of nuclear resources in this country. Evidently a pair of journalists with a backpack walked right in to a supposedly secure area with no questions asked.

So while I applaud their work on alternative energy, they ought to work on security while they're at it.

 

[CycloWizard]

I'm very surprised something this basic is seen as a big breakthrough. This kind of thing has been done in conventional chemical reaction catalysis for decades for the very same reasons. BeO is even a common substrate for catalyst deposition...

Originally posted by: Pabster
FWIW, Purdue University was recently the subject of an investigation into security of nuclear resources in this country. Evidently a pair of journalists with a backpack walked right in to a supposedly secure area with no questions asked.

So while I applaud their work on alternative energy, they ought to work on security while they're at it.

Any university with radioactive materials has this problem. Here, we have keypad combination locks on the door, but they still get propped open sometimes. Heck, if you really wanted, you could break the window and take the stuff. The government (nor anyone else) can keep you safe if someone really wants to kill you.

 

[zephyrprime]

They should put some AS5 in those rods and then they'd reach 40C on air easy. 30C with water cooling. I bet some fins on those rods would help heat transfer also.

 

[EatSpam]

Originally posted by: 2cpuminimum
This sounds like a great advance, but wouldn't it be much better to start using breeder reactors? Why hasn't carter's 1977 decree not to use fast breeder reactors been repealed yet?

That's a good question... anyone know?

 

[kyp275]

Originally posted by: zephyrprime
They should put some AS5 in those rods and then they'd reach 40C on air easy. 30C with water cooling. I bet some fins on those rods would help heat transfer also.

I think they should try to incorporate heatpipes into those rods on top of the fins.

 

[Stretchman]

That's fascinating stuff. I love to hear about progress in these areas.

 

[K1052]

Originally posted by: EatSpam

Originally posted by: 2cpuminimum
This sounds like a great advance, but wouldn't it be much better to start using breeder reactors? Why hasn't carter's 1977 decree not to use fast breeder reactors been repealed yet?

That's a good question... anyone know?

Very low uranium costs over the last couple decades and opposition to the reprocessing facilites that would have to handle the fuel.

Many of the anti-nuclear groups cite weapons proliferation concerns since these facilites would handle large amounts of enriched plutonium (which was the basis for the Carter ban). If done under close DOE/NRC control I don't see how this is really much of a concern since the government ran their own breeders to create Plutonium for the weapons program for decades.

 

[Moonbeam]

The half life of Uranium is 4.5 billion years, the half life of Plutonium is 24,000 years. Imagine what humans would do to pigs if pig sh!t lasted that long. Look in the mirror. You can outsh!t any pig.

 

[Googer]

:thumbsup:

 

[Ryan]

MMMMMMMMMMMMMmmmmmmmmmmmmm - PURDUUUUUUUUUUEEEEEEEEEEEEEEEEEEEEEEEEEE is hot

 

[czech09]

Purdue Engineers = cool, especially when they help you with Circuits HW hehe.

 

[Hacp]

More nuclear fuel=better.

 

[PurdueRy]

Originally posted by: Future Shock
GO PURDUE!!!

Exactly!

FWIW, Purdue University was recently the subject of an investigation into security of nuclear resources in this country. Evidently a pair of journalists with a backpack walked right in to a supposedly secure area with no questions asked.

Our nuclear reactor is tiny....I doubt anything would even happen if someone had gotten there...but I haven't even heard this story so I am skeptical.

They should put some AS5 in those rods and then they'd reach 40C on air easy. 30C with water cooling. I bet some fins on those rods would help heat transfer also.

Yeah actually we were thinking about overclocking it...what do you think??

The half life of Uranium is 4.5 billion years, the half life of Plutonium is 24,000 years. Imagine what humans would do to pigs if pig sh!t lasted that long. Look in the mirror. You can outsh!t any pig.

Thats true, I can't...

MMMMMMMMMMMMMmmmmmmmmmmmmm - PURDUUUUUUUUUUEEEEEEEEEEEEEEEEEEEEEEEEEE is hot

Yes we are....We have a fraternity you might like....

Purdue Engineers = cool, especially when they help you with Circuits HW hehe.

You are very welcome