Thermo-chemical Characteristics of Powder Fabricated by Oxidation of Spent PWR Fuel
Thermochemcial characteristics of powder fabricated using oxidation treatment of spent PWR fuel and SIMFUEL were evaluated for recycling of spent fuel such as DUPIC process. Especially, the influence of spent fuel burn-ups on the powder fabrication characteristics was experimentally evaluated, ranging from 27,300 to 65,000 MWd/tU. Densities of powder manufactured from an oxidation, OREOX and the milling processes at the same process conditions were compared as a function of the fuel burn-ups respectively. Also, based on chemical analysis results, homogeneity of fissile elements in oxidized powder was confirmed. Keywords—Spent PWR fuel, DUPIC, Oxidation, OREOX, Powder, Chemical analysis
Studies of Reaction Processesfor Voloxidation Methods
The oxidation of UO2 pellets contained in 316 stainless steel cladding was studied. Depleted uranium oxide pellets within the cladding were partially reacted with exposure to an oxidant at one end. The partially reacted samples prepared at temperatures of 325, 450, 500, and 600°C were spatially mapped by neutron diffraction to determine phase distribution. Measurements were taken at the Oak Ridge National Laboratory (ORNL) High Flux Isotope Reactor (HFIR) on the HB-2B beam line, which is equipped with an automated sample positioning system and a collimated neutron beam. After neutron interrogation, the samples were cross-sectioned to allow for correlation of the data with micrographs. The study presented is novel in the use of spatial mapping by neutron diffraction to study uranium oxide phase distribution of spatially oxidized clad pellets and density gradient of the oxide product above the reaction interface. 3.
The release of fission products from degraded UO2 fuel: Thermochemical aspects
Abstract This review describes the chemical aspects of the release of the important fission products. Their behaviour in the fuel, in the reactor coolant system (primary system), and during core-concrete interactions, is discussed. Special attention is given to thermochemical modeling to incorporate the results of recent studies on the acquisition of thermochemical data for relevant species by experimental and evaluation techniques.