Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

MIT engineers work to improve nuclear power generation

26.09.2006
MIT researchers are working on several innovations that could make existing nuclear power plants more efficient and safer to run. These include a new fuel and a way to boost the cooling capability of ordinary water.

With U.S. electricity demand projected to increase by nearly 50 percent over the next 25 years, the Bush administration and others see nuclear power as an increasingly attractive energy option.

Nuclear power has the potential to help make the United States less dependent on foreign fuel and to cut the carbon dioxide emissions that contribute to global warming.

Pilot models of next-generation nuclear plants are being built around the world, but such plants are not likely to produce consumer electricity in the United States for 20 years or more, said Pavel Hejzlar, a principal research scientist in MIT's Department of Nuclear Science and Engineering.

In a nuclear power plant, the fission of uranium atoms provides heat to produce steam for generating electricity. While nuclear plants are already energy-intensive - one pickup-truck full of uranium fuel can supply enough electricity to run a city for a year - Hejzlar and Mujid S. Kazimi, the TEPCO Professor of Nuclear Engineering, professor of mechanical engineering and director of the Center for Advanced Nuclear Energy Systems, wanted to make fuel go even further.

Uranium fuel typically is formed into cylindrical ceramic pellets about a half-inch in diameter. The pellets look like a smooth, black version of food pellets for small animals.

In a three-year project completed recently for the U.S. Department of Energy, Hejzlar and Kazimi teamed up with Westinghouse and other companies to look at how to make a fuel for one kind of reactor, the pressurized water reactor (PWR), 30 percent or more efficient while maintaining or improving safety margins.

They changed the shape of the fuel from solid cylinders to hollow tubes. This added surface area that allows water to flow inside and outside the pellets, increasing heat transfer. The new fuel turned out even better than Hejzlar dared hope. It proved to be easy to manufacture and capable of boosting the plant power output of PWRs by 50 percent.

The next step is to commercialize the fuel concept, which will include testing a limited number of rods filled with the new pellets in an operating reactor and examining the results to ensure the safety and performance of the new fuel.

Water is used in many nuclear reactors to help generate electricity and to ensure safe operation. Now Jacopo Buongiorno, assistant professor of nuclear science and engineering, has come up with a way to change water's thermal properties. This change may contribute to plants' safety while boosting their power density, or the amount of energy they can pump out.

In these reactors, energy released from fission of the fuel's atoms is harnessed as heat in water, which creates steam that drives turbines and produces electricity. In both PWRs and their close cousin, the boiling water reactor (BWR), that steam is turned back into water and reused. Water also is used as a coolant in the reaction process and in safety systems.

The efficiency of PWRs and BWRs is limited to around 33 percent because water can be heated to only a certain temperature and only a certain amount of heat can be taken out of water. If that limit were pushed higher, more heat could be extracted, and the plant would generate more energy at a lower cost.

This may soon be possible, thanks to Buongiorno.

His laboratory works on nanofluids - base fluids such as water interspersed with tiny particles of oxides and metals only billionths of a meter in diameter. Buongiorno's nano-spiked water, transparent but somewhat murky, can remove up to two times more heat than ordinary water, making it an ideal substance for nuclear plants.

The nanoparticles "change some key properties of the way water behaves when it boils," Buongiorno said, improving its heat transfer capabilities.

The spiked water could provide an extra measure of protection in the event of a nuclear meltdown. In a meltdown, molten nuclear fuel sinks to the bottom of the big stainless steel pot containing it, which sits in a cavity of cooling water. If the excess heat is not removed, the molten fuel could breach the pot.

Nanoparticles in the water that cools the outer surface of the vessel raise the amount of heat that can be drawn away from the core, making the plant less susceptible to the negative repercussions of a possible meltdown.

The key issue to be resolved before nanofluids can be used in nuclear plants, Buongiorno said, is the stability of the nanoparticles, which could agglomerate and settle quickly if appropriate chemical and thermal conditions are not carefully maintained.

This work is funded by the Idaho National Laboratory, the nuclear energy vendor AREVA and the MIT Nuclear Reactor Laboratory.

Elizabeth A. Thomson | MIT News Office
Further information:
http://www.mit.edu

More articles from Power and Electrical Engineering:

nachricht Supersonic waves may help electronics beat the heat
18.05.2018 | DOE/Oak Ridge National Laboratory

nachricht Researchers control the properties of graphene transistors using pressure
17.05.2018 | Columbia University

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Research reveals how order first appears in liquid crystals

23.05.2018 | Life Sciences

Space-like gravity weakens biochemical signals in muscle formation

23.05.2018 | Life Sciences

NIST puts the optical microscope under the microscope to achieve atomic accuracy

23.05.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>