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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Preparation of UC0.07-0.10N0.90-0.93 spheres for TRISO coated fuel particles

The U.S. Department of Energy is considering a new nuclear fuel, which should be much more impervious during a loss of coolant accident. The fuel would consist of tristructural isotropic coated particles with dense uranium nitride (UN) kernels. The objectives of this effort are to make uranium oxide microspheres with adequately dispersed carbon nanoparticles and to convert these microspheres into UN kernels. Recent improvements to internal gelation process were successfully applied to the production of uranium gel spheres with different concentrations of carbon black. After the spheres were washed, a simple, two-step heat profile was used to produce kernels with a chemical composition of UC0.07 0.10N0.90 0.93. The first step involved heating the microspheres to 2023 K in a vacuum, and in the second step, the microspheres were held at 1873 K for 6 hrs in nitrogen.

internal gelation↗
DOE OSTI2022

AGR Program TRISO Fuel Topical Report Dialog

AGR Program Overview and Current Activities Fission Product Transport Data Short-Lived Fission Product Release Fuel Performance Margin Data Oxidation Testing Data

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2016

Initial examination of fuel compacts and triso particles from the US AGR-2 irradiation test - 18443

Post-irradiation examination was completed on two as-irradiated compacts from the US Advanced Gas Reactor Fuel Development and Qualification Program's second irradiation test. These compacts were selected for examination due to indications that they may have contained particles that released cesium due to a failed or defective SiC layer. The coated particles were recovered from these compacts by electrolytic deconsolidation of the surrounding graphitic matrix in nitric acid. The leach-burn-leach (LBL) process was used to dissolve and analyze exposed metallic elements (actinides and fission products), and each particle was individually surveyed for relative cesium retention with the Irradiated Microsphere Gamma Analyzer (IMGA). Data from IMGA and LBL examinations provided information on fission product release during irradiation and whether any specific particles had below-average retention that could be related to coating layer defects or radiation-induced degradation. A few selected normal-retention particles and six with abnormally-low cesium inventory were analyzed using x-ray tomography to produce three-dimensional images of the internal coating structure. Four of the low-cesium particles had obviously damaged or degraded SiC, and x-ray imaging was able to guide subsequent grinding and polishing to expose the regions of interest for analysis by optical and electron microscopy. Additional particles from each compact were also sectioned and examined to study the overall radiation-induced microstructural changes in the kernel and coating layers. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2016

Electron probe microanalysis of irradiated and 1600 deg. C safety-tested AGR-1 Triso fuel particles with low and high retained {sup 110M}Ag - 18570

Advanced Gas Reactor (AGR)-1 fuel Compact 4-3-3 achieved 18.63% FIMA and was exposed to a safety test at 1600 deg. C. Two particles, AGR1-433-003 and AGR1-433-007, with measured-to-calculated {sup 110m}Ag inventories of <22% and 100%, respectively, were selected for electron microprobe analysis to determine whether the distribution or abundance of fission products differed proximally and distally from the deformed kernel in AGR1-433-003 and how this compared to fission product distribution in AGR1-433-007. On the deformed side of AGR1-433-003, xenon, cesium, iodine, europium, strontium, and tellurium concentrations in the kernel buffer interface near the protruded kernel were up to six times higher than on the opposite, non-deformed side. At the silicon carbide (SiC)-inner pyrolytic carbon (IPyC) interface proximal to the deformed kernel, palladium and silver concentrations were 1.2 and 0.04 wt% respectively. On the SiC-IPyC interface distal from the kernel deformation, those elements measured 0.4 and 0.01 wt%, respectively. Palladium and silver concentrations at the SiC-IPyC interface of AGR1-433-007 were 2.05 and 0.05 wt.%, respectively. Rare earth element concentrations at the SiC-IPyC interface of AGR1-433-007 were ten times higher than at the SiC-IPyC interfaces measured in AGR1-433-003. Palladium permeated the SiC layer of AGR1-433-007 and the SiC layer of the non-deformed side of AGR1-433-003. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗