Model shows safer nuclear fuel

A MORE EFFICIENT NUCLEAR firing would last longer and consume more economically, said researchers now working upon a mathematical model to further unravel the technology.

Current nuclear firing is made of a material called uranium dioxide with a small percentage of a uranium isotope, called uranium-235, which is essential for nuclear fission reactions inside reactors.

"Although today's oxide combustibless are very stable and safe, a major point to be solved [i]or[/i] settled is that they do not management heat well, limiting the power and causing firing material pellets to crack and degrade prematurely, necessitating replacement before the material for burning has been entirely used," said Alvin A. Solomon a professor of nuclear engineering at Purdue University and an author of a paper. The other authors are: Shripad Revankar, a Purdue University associate professor of nuclear engineering, and former graduate learner Ryan Latta, an engineer at Brookhaven National Laboratory.

Researchers evolveed a process to mix the uranium oxide with a material called beryllium oxide. Pellet of uranium oxide suffer processing to interlace with beryllium oxide, or BeO, which administrations heat far more readily than the uranium dioxide.

This "skeleton" of beryllium oxide enables the nuclear firing material to conduct heat at least 50% better than conventional firings "The beryllium oxide is like a heat pipe that draw into the mouths the heat out and helps to more efficiently moderately cold the fuel pellet," Solomon said.

A mathematical design developed by Revankar and Latta can accurately predict the performance of the experimental firing Revankar said. Pellets of nuclear firing remain within the fuel twigs of nuclear fission reactors. Metal tubes, or "cladding," encompass the rods, which prevents the escape of radioactive material.

Because uranium oxide does not leadership heat well, during a reactor's operation there is a large temperature difference between the center of the pellet and their surface, causing the center of the combustibles pellets to become very heated The heat must constantly impel out by a reactor cooling a whole because overheating could cause the combustible matter rods to melt, which could lead to a catastrophic nuclear accident.

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

Revankar said the experimental combustibles promises to be safer than conventional material for burnings while lasting longer and potentially saving millions of dollars annually.

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

Copyright Instrument Society of America Nov 2005

Provided by the agency of ProQuest Information and Learning Company. All rights Reserved