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Umeda, Maki; Chudo, Hiroyuki; Imai, Masaki; Sato, Nana; Saito, Eiji
Review of Scientific Instruments, 94(6), p.063906_1 - 063906_8, 2023/06
Times Cited Count：0 Percentile：0(Instruments & Instrumentation)Chudo, Hiroyuki; Imai, Masaki; Matsuo, Mamoru; Maekawa, Sadamichi; Saito, Eiji
Journal of the Physical Society of Japan, 90(8), p.081003_1 - 081003_11, 2021/08
Times Cited Count：3 Percentile：41.09(Physics, Multidisciplinary)Imai, Masaki; Chudo, Hiroyuki; Matsuo, Mamoru; Maekawa, Sadamichi; Saito, Eiji
Physical Review B, 102(1), p.014407_1 - 014407_5, 2020/07
Times Cited Count：6 Percentile：38.95(Materials Science, Multidisciplinary)
Dy
Fe
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detected by the Barnett effectImai, Masaki; Chudo, Hiroyuki; Ono, Masao; Harii, Kazuya; Matsuo, Mamoru; Onuma, Yuichi*; Maekawa, Sadamichi; Saito, Eiji
Applied Physics Letters, 114(16), p.162402_1 - 162402_4, 2019/04
Times Cited Count：20 Percentile：73.01(Physics, Applied)Imai, Masaki; Ogata, Yudai*; Chudo, Hiroyuki; Ono, Masao; Harii, Kazuya; Matsuo, Mamoru*; Onuma, Yuichi*; Maekawa, Sadamichi; Saito, Eiji
Applied Physics Letters, 113(5), p.052402_1 - 052402_3, 2018/07
Times Cited Count：18 Percentile：65.6(Physics, Applied)Ismailov, K.*; Nishihara, Kenji; Saito, Masaki*; Sagara, Hiroshi*
Annals of Nuclear Energy, 56, p.136 - 142, 2013/06
Times Cited Count：6 Percentile：44.02(Nuclear Science & Technology)The transmutation of iodine-129 in accelerator driven system (ADS) is studied. The sodium iodide assembly loadings inside the core of ADS and in the surrounding core region are considered. The introduced concept of ADS with a power of 800 MWt is able to transmute 250 kg/y of minor actinides (MAs) and 46 kg/y of Iodine-129 that supports ten PWRs. The initial loading masses of MAs and I-129 in ADS were equal to 3810 kg and 824 kg, respectively.
Kamiyama, Kenji; Saito, Masaki*; Matsuba, Kenichi; Isozaki, Mikio; Sato, Ikken; Konishi, Kensuke; Zuyev, V. A.*; Kolodeshnikov, A. A.*; Vassiliev, Y. S.*
Journal of Nuclear Science and Technology, 50(6), p.629 - 644, 2013/06
Times Cited Count：19 Percentile：81.37(Nuclear Science & Technology)In core disruptive accidents of sodium cooled fast reactors, fuel discharge from the core region reduces the possibility of severe re-criticality events. In-core coolant channels such as the control-rod guide tube and a concept of the FAIDUS (Fuel Assembly with Inner Duct Structure) provide effective fuel discharge paths if effects of sodium in these paths on molten fuel discharge are limited. Two series of experiments conducted in the present study showed that the discharge path can be entirely voided by the vaporization of a part of the coolant at the initial melt discharge phase, that this is followed by coolant vapor expansion, and that melt penetrates significantly into the voided channel. In conclusion, the effects of the sodium on fuel discharge are limited and therefore in-core coolant channels provide effective fuel discharge paths for reducing neutronic activity.
Am content on homogenization of denatured Pu with broad range of neutron energy based on U irradiation test in the experimental fast reactor JoyoShiba, Tomooki*; Sagara, Hiroshi*; Onishi, Takashi; Koyama, Shinichi; Maeda, Shigetaka; Han, C. Y.*; Saito, Masaki*
Annals of Nuclear Energy, 51, p.74 - 80, 2013/01
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)The design consideration of DU-Am oxide fuel pin was performed for Pu denaturing in the framework of the protected plutonium production based on the irradiation analyses of the depleted U (DU) samples irradiated in the environment of broad range of neutron energy in the experimental fast reactor Joyo. From the results of irradiation analyses of DU, it was confirmed that there is a strong dependence of transmutation behavior of DU on the resonance neutron ratio even in a fast reactor. Also, it was confirmed that there is a strong effect of sample material form and shape on generated Pu nuclide inventory especially near the reflector area (
20% resonance neutron ratio), because of the intensive self-shielding of 
U, though less is expected for Am. Sensitivity study of hypothetical DU-Am oxide fuel pellet irradiation on neutron energy and burn-up was performed to evaluate significant gradient of radial Pu isotopic composition profile (e.g., from 12 to 18% distribution in 3% Am doping, in 30% resonance neutron ratio and in 4.0
10
[n/cm
] of neutron fluence inside a large pellet with softened neutron spectrum), and vulnerability of the fuel pellet surface in terms of Pu denaturing was revealed. Design consideration of radial zoning of Am content was introduced to flatten the radial distribution of isotopic composition of Pu. The results of radial zoning of Am (4% and 3% of Am in the outer and inner zone of DU-Am oxide fuel pellet) in hypothetical irradiation neutronics analysis showed the radial profile of produced Pu is over 15 at.% of Pu isotopic composition in any zone and meets the criteria of Kimura et al. based on decay heat of Pu to impede utilization to fission explosive devices.
Ab
nades, A.*; 
lvarez-Velarde, F.*; Gonzlez-Romero, E. M.*; Ismailov, K.*; Lafuente, A.*; Nishihara, Kenji; Saito, Masaki*; Stanculescu, A.*; Sugawara, Takanori
Nuclear Engineering and Design, 254, p.148 - 153, 2013/01
Times Cited Count：1 Percentile：10.69(Nuclear Science & Technology)The design of Accelerator Driven Systems (ADS) requires the development of simulation tools that are able to describe in a realistic way their nuclear performance and transmutation rate capability. In this publication, we present an evaluation of state of the art Monte Carlo design tools to assess their performance concerning transmutation of long-lived fission products. This work, performed under the umbrella of the International Atomic Energy Agency, analyses two important aspects for transmutation systems: moderation on Lead and neutron captures of 
Tc, 
I and 
I. The analysis of the results shows how shielding effects due to the resonances at epithermal energies of these nuclides affects strongly their transmutation rate. The results suggest that some research effort should be undertaken to improve the quality of Iodine nuclear data at epithermal and fast neutron energy to obtain a reliable transmutation estimation.
Matsumoto, Koji*; Sagara, Hiroshi*; Han, C. Y.*; Onishi, Takashi; Saito, Masaki*; Yamauchi, Ippei*
Transactions of the American Nuclear Society, 107(1), p.1018 - 1019, 2012/11
Protected plutonium production (P
) with a high proliferation-resistance was proposed by increasing the Pu ratio in the total plutonium through minor actinides (MAs) doping into the fresh blanket fuel. Moderator effect on P was evaluated. As a result, the transmutation ratio is larger with the heterogeneous moderator than with the homogeneous one, and the isotopic ratio of Pu was increased.
Onishi, Takashi; Koyama, Shinichi; Shiba, Tomooki*; Sagara, Hiroshi*; Saito, Masaki*
Progress in Nuclear Energy, 57, p.125 - 129, 2012/05
Times Cited Count：1 Percentile：10.14(Nuclear Science & Technology)In order to develop blanket fuel with high proliferation resistance in fast breeder reactor, chemical analysis of nine U samples irradiated in experimental fast reactor Joyo and Pu contents and Pu isotopic composition of the samples were measured. As results, dependence of Pu production behavior from U on neutron spectra was revealed.
Permana, S.; Suzuki, Mitsutoshi; Suud, Z.*; Saito, Masaki*
Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 7 Pages, 2011/12
Spent fuel (SF) of light water reactors (LWR) is loaded to increase breeding capability and intrinsic aspect of proliferation resistance. This present study intends to evaluate the effect of different loaded doping materials in the blanket region of FBR to the reactor performance and plutonium proliferation resistance level. Basic reactor operation is adjusted to reach 800 days operation by adopting 4 fuel batches systems of Japan Sodium Fast Reactor (JSFR) design. LWR plutonium compositions of Isotopic Pu and Pu show more sensitive to the decay time due to it shorter half-life which affect to the vector composition of plutonium as well as minor actinide (MA) as a function of decay time.
Ismailov, K.*; Nishihara, Kenji; Sasa, Toshinobu; Sugawara, Takanori; Saito, Masaki*
Annals of Nuclear Energy, 38(10), p.2180 - 2186, 2011/10
Times Cited Count：4 Percentile：32.59(Nuclear Science & Technology)In present study the benchmarking of TARC experiment was done. MCNPX code with JENDL-HE, JENDL-4, JENDL-3.3 and LA-150 nuclear data libraries were used for simulations. The calculated neutron fluences, energy-time correlations of resonance reactions and transmutation rates of Tc and 
I were compared with experimental measurements. On the base of comparative analysis of simulations the validation of nuclear data libraries was performed and recommendations were given, as follows: (1) the JENDL-4 library contains better neutron elastic cross-section data for natural lead in energy range from 0.01 eV to 100 eV comparing to other considered data libraries; (2) the JENDL-HE (JENDL-3.3) has better neutron inelastic scattering cross-sections for lead in energy range of 1-3 MeV, although the experimental errors in neutron fluence are rather large; (3) neutron capture cross-sections of I in JENDL-4 library should be used for I transmutation process simulations.
Permana, S.; Suzuki, Mitsutoshi; Saito, Masaki*
Proceedings of 19th International Conference on Nuclear Engineering (ICONE-19) (CD-ROM), 7 Pages, 2011/10
Trans-uranium (TRU) compositions of LWR and multi-cycle FBR have been loaded in the FBR design by adopting 4 fuel batches system. 800 days of cycle length was used to investigate the proliferation resistance of plutonium as well as core performance, during reactor operation. Different compositions of TRU as initial fuel composition affect to the fuel behavior, criticality condition and fuel breeding capability. It shows less excess reactivity and better fuel breeding for MA doping in the core. High decay heat (DH) and spontaneous fission neutron (SFN) compositions of plutonium which is mainly caused by high production of even mass of plutonium isotopes will be compared from both typical trans-uranium compositions of LWR and FBR.
Ismailov, K.*; Saito, Masaki*; Sagara, Hiroshi*; Nishihara, Kenji
Progress in Nuclear Energy, 53(7), p.925 - 929, 2011/09
Times Cited Count：10 Percentile：60.88(Nuclear Science & Technology)A feasibility study on natural uranium spallation target in accelerator-driven system (ADS) for minor actinide (MA) transmutation was performed. As a result of comparative study of uranium and lead-bismuth (PbBi) targets in the bare case without blanket surrounding, it was found that uranium target had better neutron generation performance, but limited by the geometrical size due to high neutron absorption in U. In ADS for MA transmutation, uranium used as target instead of PbBi also absorbs neutrons passing the target area. More realistic concept of pin type uranium spallation target cooled by liquid PbBi was considered aiming at enhancing spallation target performance in terms of neutron generation efficiency and operation temperature. The uranium pin target design had nothing better effects on neutron balance of such system than a conventional PbBi target in ADS and it was concluded that uranium target was not suitable for the full-scale ADS.
Permana, S.; Suzuki, Mitsutoshi; Saito, Masaki*
Transactions of the American Nuclear Society, 104(1), p.714 - 715, 2011/06
Material attractiveness concepts for evaluating the level of proliferation resistance of nuclear fuel have been evolving and can be useful for determining general rules to assess the potential use of nuclear material for explosive devices. The two approaches examined here for evaluating material attractiveness are the attractiveness (ATTR) and figure of merit (FOM) concepts. Similar trend of material attractiveness level with ATTR and FOM is obtained by introducing MA doping in the blanket region and these loading MA is effective to reduce the material attractiveness level to practically unusable level of ATTR and low attractiveness level of FOM2.
Permana, S.; Suzuki, Mitsutoshi; Saito, Masaki
Journal of Nuclear Science and Technology, 48(5), p.724 - 733, 2011/05
Times Cited Count：10 Percentile：57.01(Nuclear Science & Technology)Fuel behaviors of the large fast breeder reactor have been investigated as well as material attractiveness based on isotopic plutonium composition for evaluating proliferation resistance aspect in regards to combine evaluation of decay heat and spontaneous fission neutron barrier as key parameters of isotopic material barrier. Trans-uranium fuel TRU in the core regions and doping MA in the blanket regions as the option of loading MA, produces higher Pu composition for denaturing plutonium which mainly comes from converted 
Np. Isotopic plutonium composition of TRU fuel has relatively less than its Pu composition of MOX fuel except for Pu composition which is obtained higher composition than MOX fuel. MA in the core or blanket regions which produces higher Pu composition becomes the key role for obtaining higher level material barrier of decay heat and spontaneous fission neutron compositions.
Permana, S.; Suzuki, Mitsutoshi; Saito, Masaki
Nuclear Engineering and Design, 241(1), p.101 - 117, 2011/01
Times Cited Count：11 Percentile：64.09(Nuclear Science & Technology)The effect of trans-uranium (TRU) fuel loading on the reactor core performance as well as the actinide and plutonium composition in the core and blanket regions has been analyzed based on the large FBR type. Isotopic plutonium composition of TRU fuel obtains less composition than that of MOX fuel except for Pu composition which obtains relatively higher composition. The significantly increasing composition is shown by Pu for TRU fuel in the core region as well as its increasing value in the blanket region for doping MA case. Excess reactivity can be reduced significantly and an additional breeding gain can be obtained by TRU fuel in comparison with MOX fuel. Doping MA in the blanket regions reduces the criticality for a small reduction value and it gives a reduction value of breeding ratio.
Mishima, Kaichiro*; Saito, Masaki*; Nagata, Takashi*
Nihon Genshiryoku Gakkai-Shi ATOMO
, 52(9), p.536 - 552, 2010/09
The 1st of this series that was entitled, "Accelerating Fast Reactor Development: Start of Operation of Commercial Reactors in 2020" introduced mainly the activated development plan and in the major countries. This article introduces the development of the sodium-cooled fast reactor and related fuel cycle that each country is devoting one's energies to development, maily following the presentation in International Conference (FR09) held by organized by IAEA in December 2009, including the situation before and behind the conference. Especially, the development in Russia, India, China, USA, Republic of Korea, France and Japan.
Koyama, Shinichi; Osaka, Masahiko; Ito, Masahiko*; Sagara, Hiroshi*; Saito, Masaki*
Journal of Nuclear Science and Technology, 47(8), p.661 - 670, 2010/08
Times Cited Count：6 Percentile：40.28(Nuclear Science & Technology)A project on Protected Plutonium Production (P) was proposed by Tokyo Institute of Technology as part of a non-proliferation research program for plutonium (Pu) utilization in nuclear reactors. A determination of Pu isotopes in Np samples irradiated in the experimental fast reactor JOYO was done to evaluate Pu production from Np under fast neutron spectra. In the mean time, 2, 5 and 10% Np-containing U samples were irradiated in the Advanced Test Reactor at the Idaho National Laboratory (INL) to evaluate Pu production in the thermal neutron region. The verified transmutation data can be used to design fuel pellets for non-proliferation.
