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Isozaki, Misaki; Sasaki, Shinji; Maeda, Koji; Katsuyama, Kozo
JAEA-Technology 2015-058, 28 Pages, 2016/03
During irradiation in the fast reactor "JOYO", the changes of fuel structures with the formation of central void occur in the uranium-plutonium mixed oxide fuels (MOX fuels) because of radial temperature gradient. The changes of element (U, Pu, and so on) distributions along radial direction proceed from these changes. Therefore, it is important to study the changes of fuel structures of the minute area in fuel pellet and the changes of element distribution behavior for development of fast reactor fuels. In order to make detailed observations of microstructure and elemental analyses of fuel samples, a field emission scanning electron microscope (FE-SEM) equipped with a wavelength-dispersive X-ray spectrometer (WDS) and an energy-dispersive X-ray spectrometer (EDS) were installed in Fuel Monitoring Facility (FMF). The samples of this FE-SEM are very high radioactivity because the samples contain the nuclear fuel elements (U, Pu, etc.), the fission products (Cs, Rh, etc.) and activation product (Co, Mn etc.). Owing to this, it is necessary to prevent leakage of radioactive materials (particularly, U, Pu is need tight accountancy in law) and to protect operators from radiation. In this installation of FE-SEM, it is selected JSM-7001F (made by JEOL) for base model. The notable modified points were as follows. (1) To protect operators from radiation, lead shields was installed around FE-SEM. (2) To prevent leakage of radioactive materials, the instrument was attached to a remote control air-tight sample transfer unit between a shielded hot cell and the FE-SEM and the instrument was fixing rigid structure without vibration damper. (3) The design and manufacture the lead shields with consideration of instrument maintainability. This paper was described the summary of FE-SEM, the notable modified points, the ways of FE-SEM installation, the result of performance test.
Sasaki, Shinji; Isozaki, Misaki; Ishimi, Akihiro; Maeda, Koji
no journal, ,
Fuel rods containing annular MOX pellets were irradiated at over 400 W/cm to burnup of nearly 30,000 MWd/t in the experimental fast reactor, Joyo. The microstructural change and redistribution of Pu and U in the pellets were investigated by ceramography and EPMA.
Sasaki, Shinji; Isozaki, Misaki; Ishimi, Akihiro; Maeda, Koji
no journal, ,
no abstracts in English