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Compacts with/without Uranium ParticlesIshii, Tetsuya; Yuda, Ryoichi*; Hirai, Mutsumi*; Tsuboi, Yasushi*; Ukai, Shigeharu
Journal of Nuclear Science and Technology, 41(12), p.1204 - 1210, 2004/00
Times Cited Count：2 Percentile：17.1(Nuclear Science & Technology)The thermal conductivities of granular UO compacts with and without uranium particles were measured to evaluate the thermal performance of vibro-packed granular MOX fuels containing metallic fine particle oxygen getters. The thermal conductivity of the compact with 10wt.% of the uranium particles was higher than without uranium particles and after heating beyond 1408K, the melting point of the uranium particle, the thermal conductivity further increased..The evaluation model for analyzing such phenomena were developed and it was revealed that once the UO compact with the uranium particles was exposed to the temperature beyond 1408K, the uranium particle should melt and provide interconnect area between the UO granules and uranium particles, and between the uranium particles with each other. The resulting increase of the thermal conductivity was reasonably expressed by the effect of necks in the compact on the heat conduction.
Kase, Takeshi; Koizumi, Tsutomu; Yuda, Ryoichi*; Matsuyama, Shinichiro*
no journal, ,
no abstracts in English
Ishii, Tetsuya; Yuda, Ryoichi*; Matsuyama, Shinichiro*
no journal, ,
For improvement of the physical properties of MOX fuels containing americium, the method that metallic uranium particles are mixed with fuel powders and sintered could be one of the probable techniques. In this work, the feasibility of the method was studied using UO with metallic uranium particles
Morihira, Masayuki; Segawa, Tomoomi; Matsuyama, Shinichiro*; Yuda, Ryoichi*; Namekawa, Takashi
no journal, ,
Removal of excess oxygen in a MOX fuel element during the irradiation is required to attain a high burn up of FBR fuel because the increase of the oxygen potential in a fuel element during the irradiation accelerates FCCI. The oxygen getter method is an alternative to the low O/M ratio pellet option. Preliminary surveillance suggested Zr and Ti were most expecting candidates. In this study, the compatibility of these candidate materials with MOX, UO and FMS as well as their oxygen uptake abilities were evaluated.
Morihira, Masayuki; Segawa, Tomoomi; Namekawa, Takashi; Matsuyama, Shinichiro*; Yuda, Ryoichi*; Mizusako, Fumiki*
no journal, ,
Investigation of oxygen getter option is in progress for FBR MOX fuel to restrain the cladding inner surface corrosion at the high burn-up of 150 GWd/t. Evaluation of the requirement for the oxygen getter materials showed that Zr and Ti were promising candidate materials. Method of loading getter materials into a fuel element was also investigated. Their oxygen uptake ability and restructuring behavior during the oxidation were evaluated by the heating at 1573 K for 10 h under the controlled oxygen potential. As a result, it was shown that both Zr and Ti were available as an oxygen absorber but Ti was superior from the geometrical stability.
and FMSSegawa, Tomoomi; Morihira, Masayuki; Namekawa, Takashi; Matsuyama, Shinichiro*; Yuda, Ryoichi*; Mizusako, Fumiki*
no journal, ,
Heating tests were carried out for the disc pares of Zr-FMS, Ti-FMS, Zr-UO and Ti-UO to evaluate the compatibility of the candidate materials of oxygen getter with UO and FMS, and the interfaces of each disc were investigated. No reaction was observed between Zr and UO also FMS in the test conditions. For Ti and FMS, Ti-Fe-O phase with the maximum thickness of 14 
m was formed in the Ti disc at 700
C for 100 h but no penetration of Ti into FMS disc was observed. For Ti and UO, Ti-U or Ti-U-O phase were formed near the surface of the Ti disc but these were limited in Ti disc side. No penetration of Ti into UO disc was observed. As a result, it is considered that no harmful influence is expected for Zr and Ti on the integrity of UO and FMS cladding.
