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 Did you know that the wrapping of Easter eggs benefits from specialty light sources?
13.04.2017 | Heraeus Noblelight GmbH

nachricht To e-, or not to e-, the question for the exotic 'Si-III' phase of silicon
05.04.2017 | Carnegie Institution for Science

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: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

DGIST develops 20 times faster biosensor

24.04.2017 | Physics and Astronomy

Nanoimprinted hyperlens array: Paving the way for practical super-resolution imaging

24.04.2017 | Materials Sciences

Atomic-level motion may drive bacteria's ability to evade immune system defenses

24.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>