Thursday, September 25, 2008
2008 R&D 100 Winner
Advanced nuclear reactor design, particularly fourth-generation gas-cooled reactors, requires a specific shape and consistency of coated particle fuel, called tristructural isotrophic. These particles are 800 m to 1,000 m in diameter and are formed from five different layers to allow the fuel to sustain the 900°C temperatures of these reactors. Quality control of the particles is crucial. To help evaluate the optical anisotropy of the second and fourth layers of the particle, which are made of pyrocarbon, Hinds Instruments, Inc., Hillsboro, Ore., and Oak Ridge National Laboratory, Oak Ridge, Tenn., have developed the 2-MGEM Optical Anisotropy Factor Measurement System, which can measure eight elements of the Mueller matrix in reflection at near-normal incidence of a sample spot less than 4 microns in diameter. The microscope’s complex optics can measure diattenuation, principal direction, retardation, circular diattenuation, and the polarization factor. For non-depolarizing samples this information is sufficient to completely characterize the light polarization properties of the sample. Plus, 2-MGEM’s accuracy of the sample Mueller matrix is typically 0.001 or 0.002 per point, satisfying the requirements for coated particle fuel fabrication. Because variations in the diattenuation from processing conditions are often as small as 0.002, this accuracy level is crucial to the development of reliable and consistent advanced nuclear fuels.
Technology
Optical anisotropy measurement system
Developers
Oak Ridge National Laboratory
Hinds Instruments, Inc.
