Safety Testing of AGR-2 UCO Compacts 5-2-2, 2-2-2, and 5-4-1

Technical Report · Mon Aug 01 00:00:00 EDT 2016

DOI:https://doi.org/10.2172/1328314· OSTI ID:1328314

Hunn, John D. ^[1]; Morris, Robert Noel ^[1]; Baldwin, Charles A. ^[1]; Montgomery, Fred C. ^[1]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fusion and Materials for Nuclear Systems Division

Post-irradiation examination (PIE) is being performed on tristructural-isotropic (TRISO) coated-particle fuel compacts from the Advanced Gas Reactor (AGR) Fuel Development and Qualification Program second irradiation experiment (AGR-2). This effort builds upon the understanding acquired throughout the AGR-1 PIE campaign, and is establishing a database for the different AGR-2 fuel designs. The AGR-2 irradiation experiment included TRISO fuel particles coated at BWX Technologies (BWXT) with a 150-mm-diameter engineering-scale coater. Two coating batches were tested in the AGR-2 irradiation experiment. Batch 93085 had 508-μm-diameter uranium dioxide (UO₂) kernels. Batch 93073 had 427-μm-diameter UCO kernels, which is a kernel design where some of the uranium oxide is converted to uranium carbide during fabrication to provide a getter for oxygen liberated during fission and limit CO production. Fabrication and property data for the AGR-2 coating batches have been compiled and compared to those for AGR-1. The AGR-2 TRISO coatings were most like the AGR-1 Variant 3 TRISO deposited in the 50-mm-diameter ORNL lab-scale coater. In both cases argon-dilution of the hydrogen and methyltrichlorosilane coating gas mixture employed to deposit the SiC was used to produce a finer-grain, more equiaxed SiC microstructure. In addition to the fact that AGR-1 fuel had smaller, 350-μm-diameter UCO kernels, notable differences in the TRISO particle properties included the pyrocarbon anisotropy, which was slightly higher in the particles coated in the engineering-scale coater, and the exposed kernel defect fraction, which was higher for AGR-2 fuel due to the detected presence of particles with impact damage introduced during TRISO particle handling.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE), Nuclear Reactor Technologies (NE-7). Advanced Reactor Technologies
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1328314
• Report Number(s): ORNL/TM-2016/423; TRN: US1700305
• Country of Publication: United States
• Language: English

Related Subjects

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
URANIUM DIOXIDE
PYROLYTIC CARBON
SILICON CARBIDES
CARBON MONOXIDE
MINIMIZATION
FABRICATION
ARGON
IRRADIATION
URANIUM CARBIDES
COMPACTS
HYDROGEN
OXYGEN
COMPARATIVE EVALUATIONS
COATED FUEL PARTICLES
DEPOSITION
DESIGN
MIXTURES
SAFETY
TESTING
POST-IRRADIATION EXAMINATION
ANISOTROPY
COATINGS
DAMAGE
DEFECTS
DILUTION
GETTERS
MICROSTRUCTURE
ACCIDENT-TOLERANT NUCLEAR FUELS
AGR TYPE REACTORS
SILANES
TRISO
Coated Particle Fuel
AGR
PIE