Fabrication of simulated DUPIC fuel

Abstract

Simulated DUPIC fuel provides a convenient way to investigate the DUPIC fuel properties and behavior such as thermal conductivity, thermal expansion, fission gas release, leaching, and so on without the complications of handling radioactive materials. Several pellets simulating the composition and microstructure of DUPIC fuel are fabricated by resintering the powder, which was treated through OREOX process of simulated spent PWR fuel pellets, which had been prepared from a mixture of UO2 and stable forms of constituent nuclides. The key issues for producing simulated pellets that replicate the phases and microstructure of irradiated fuel are to achieve a submicrometre dispersion during mixing and diffusional homogeneity during sintering. This study describes the powder treatment, OREOX, compaction and sintering to fabricate simulated DUPIC fuel using the simulated spent PWR fuel. The homogeneity of additives in the powder was observed after attrition milling. The microstructure of the simulated spent PWR fuel agrees well with the other studies. The leading structural features observed are as follows: rare earth and other oxides dissolved in the UO2 matrix, small metallic precipitates distributed throughout the matrix, and a perovskite phase finely dispersed on grain boundaries.

RECYCLING PROCESS OF U3O8 POWDER IN MnO-Al2O3 DOPED LARGE GRAIN UO2 PELLETS

“…Cyclic heat treating is a method to utilize the mechanical stresses induced during the oxidation and reduction phase transition. This approach has been applied in the DUPIC pellet fabrication process [23]. Fig.2 shows the particle morphology evolution according to the milling time when the ball mill process was applied to the LT powder.…”

Characterization of irradiated simulated DUPIC fuel

“…A lot of fine cracks as well as large cracks were observed in the D2 pellet in radial direction compared with the D1 pellet [8]. Fig.…”

“…Precipitates of less than 1 μm in size are shown at the junction of the grain boundaries. The precipitates confirmed by EPMA were mainly Mo and Ru, and the others were Zr, Ce, Pd, and Sr in small amounts [8].…”

Thermal Expansion of Simulated Fuels with Dissolved Fission Products in a UO2 Matrix

“…A complete description of the fabrication methods and characterization results was provided in a previous publication [17].…”