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Horii, Yuta; Hirooka, Shun; Uno, Hiroki*; Ogasawara, Masahiro*; Tamura, Tetsuya*; Yamada, Tadahisa*; Furusawa, Naoya*; Murakami, Tatsutoshi; Kato, Masato
Journal of Nuclear Materials, 588, p.154799_1 - 154799_20, 2024/01
Times Cited Count：1 Percentile：68.31(Materials Science, Multidisciplinary)The thermal conductivities of near-stoichiometric (U,Pu,Am)O
doped with NdO
/SmO, which is major fission product (FP) generated by a uranium-plutonium mixed oxides (MOX) fuel irradiation, as simulated fission products are evaluated at 1073-1673 K. The thermal conductivities are calculated from the thermal diffusivities that are measured using the laser flash method. To evaluate the thermal conductivity from a homogeneity viewpoint of Nd/Sm cations in MOX, the specimens with different homogeneity of Nd/Sm are prepared using two kinds of powder made by ball-mill and fusion methods. A homogeneous Nd/Sm distribution decreases the thermal conductivity of MOX with increasing Nd/Sm content, whereas heterogeneous Nd/Sm has no influence. The effect of Nd/Sm on the thermal conductivity is studied using the classical phonon transport model (A+BT)
. The dependences of the coefficients A and B on the Nd/Sm content (C
and C
, respectively) are evaluated as: A(mK/W)=1.70 
10
+ 0.93C + 1.20C, B(m/W)=2.39 10
.
Wakaida, Ikuo; Oba, Hironori; Miyabe, Masabumi; Akaoka, Katsuaki; Oba, Masaki; Tamura, Koji; Saeki, Morihisa
Kogaku, 48(1), p.13 - 20, 2019/01
By Laser Induced Breakdown Spectroscopy and by related resonance spectroscopy, elemental and isotope analysis of Uranium and Plutonium for nuclear fuel materials and in-situ remote analysis under strong radiation condition for melt downed nuclear fuel debris at damaged core in "Fukushima Daiichi Nuclear Power Station", are introduced and performed as one of the application in atomic energy research field.
Horii, Yuta; Hirooka, Shun; Kato, Masato; Uno, Hiroki*; Ogasawara, Masahiro*; Tamura, Tetsuya*; Yamada, Tadahisa*
no journal, ,
The low-decontaminated fuel which contains significant amount of fission products (FPs) has been investigated as a fuel for the advanced fast reactor cycle. In this cycle, it is expected to reduce reprocessing cost and strengthen nuclear proliferation resistance of recovered plutonium accompanying high radiation dose FPs. However, FPs could affect on thermal properties of MOX. In particular, thermal conductivity is one of the most important properties for fuel design. Many studies have been reported on the thermal conductivity of MOX that evaluated the effect of plutonium and minor actinide (Am, Np) contents. However, the number of studies on the thermal conductivity of MOX containing FPs are limited; only Nd, Eu and Zr. In this study, thermal conductivity of MOX including NdO and SmO, which are expected to be the main FPs remaining as solid solutions in low-decontaminated fuel, was evaluated by measuring thermal diffusivity of sintered pellet. NdO powder and SmO powder was added into raw MOX powder of 20% plutonium content and they were milled by ball-mill. Sintered pellets were obtained by pressing and sintering this powder. The thermal diffusivities were measured by a laser flash method from 973 K to 1673 K at every 100 K. The thermal conductivities up to 1400K are expressed by classical phonon transport model as 
=(A+BT) where A(mK/W)=2.010
+4.810C
and B(m/W)=2.510. This means the thermal conductivity decreased with enhancement of phonon scattering by adding NdO/SmO, similar to the previous studies.
