Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Kobayashi, Fuyumi; Sumiya, Masato; Kida, Takashi; Kokusen, Junya; Uchida, Shoji; Kaminaga, Jota; Oki, Keiichi; Fukaya, Hiroyuki; Sono, Hiroki
JAEA-Technology 2016-025, 42 Pages, 2016/11
JAEA-Technology-2016-025.pdf:17.88MB
A preliminary test on MOX fuel dissolution for the STACY critical experiments had been conducted in 2000 through 2003 at Nuclear Science Research Institute of JAEA. Accordingly, the uranyl / plutonium nitrate solution should be reconverted into oxide powder to store the fuel for a long period. For this storage, the moisture content in the oxide powder should be controlled from the viewpoint of criticality safety. The stabilization of uranium / plutonium solution was carried out under a precipitation process using ammonia or oxalic acid solution, and a calcination process using a sintering furnace. As a result of the stabilization operation, recovery rate was 95.6% for uranium and 95.0% for plutonium. Further, the recovered oxide powder was calcined again in nitrogen atmosphere and sealed immediately with a plastic bag to keep its moisture content low and to prevent from reabsorbing atmospheric moisture.
Kato, Masato; Uchida, Teppei; Matsumoto, Taku; Sunaoshi, Takeo*; Nakamura, Hiroki; Machida, Masahiko
Journal of Nuclear Materials, 451(1-3), p.78 - 81, 2014/08
Times Cited Count：9 Percentile：58.08(Materials Science, Multidisciplinary)Linear thermal expansion of PuO
was measured by dilatometry in an oxygen partial pressure-controlled atmosphere. The measured data of PuO slightly increased with deviation 
. The linear thermal expansion of PuO was determined as a function of temperature and O/M ratio, and the equation for the thermal expansion coefficient was derived. Heat capacity of PuO was evaluated using this equation. The effect of O/M ratio on heat capacity was small. In addition to the vibration and dilatational terms, it is important to analyze the Schottky term in evaluating heat capacity of PuO
.
-concrete systemIzawa, Kazuhiko; Uchida, Yuriko; Okubo, Kiyoshi; Totsuka, Masayoshi; Sono, Hiroki; Tonoike, Kotaro
Journal of Nuclear Science and Technology, 49(11), p.1043 - 1047, 2012/11
Times Cited Count：12 Percentile：67.11(Nuclear Science & Technology)Possibility of criticality of fuel debris in a form of UO-concrete mixture is evaluated by calculating infinite multiplication factor (
) for a study of criticality control on the fuel debris generated through the molten core concrete interaction (MCCI) in a severe accident of a light water reactor (LWR). The infinite multiplication factor can be greater than unity, which means that handling of the mixture is subject to criticality control. This paper shows that concrete have efficient slowing-down capability of neutron and points out the necessity of further investigations on the criticality of low-enriched UO-concrete system for actual handling of fuel debris.
Okamura, Hiroki*; Tsuchida, Takashi*; Okada, Masao*; Yamagata, Ryohei; Seito, Hajime; Haruyama, Yasuyuki; Kaneko, Hirohisa
2011 Nen (Dai-29-Kai) Denki Setsubi Gakkai Zenkoku Taikai Koen Rombunshu, p.367 - 368, 2011/09
no abstracts in English
Seki, Naoki*; Kamiyama, Takashi*; Kiyanagi, Yoshiaki*; Iwasa, Hirokatsu*; Hiraga, Fujio*; Uchida, Tsutomu*; Igawa, Naoki; Yamauchi, Hiroki; Ishii, Yoshinobu; Ebinuma, Takao*; et al.
no journal, ,
no abstracts in English
Hama, Katsuhiro; Uchida, Masahiro; Amano, Kenji; Takeuchi, Ryuji; Hagiwara, Hiroki; Yoshida, Takuma*; Noshita, Kenji*; Nagasaki, Shinya*; Oe, Toshiaki*; Futakuchi, Katsuhito*
no journal, ,
The micro-chemical probe for characterization of geological environment has been developed. The performance test shows that this equipment can be applicable for the in-situ experiment.
Yamauchi, Tatsuya; Iwai, Hiroki; Hayashi, Kenta; Tsuchida, Daisuke
no journal, ,
no abstracts in English
Uchida, Hiroki*; Tada, Eiji*; Tsuru, Toru*; Ishijima, Yasuhiro; Ueno, Fumiyoshi; Yamamoto, Masahiro; Uchiyama, Gunzo; Nojima, Yasuo*; Fujine, Sachio*
no journal, ,
no abstracts in English
Sakurahara, Tatsuya; Tanaka, Satoru*; Kato, Masato; Uchida, Teppei; Uno, Hiroki*
no journal, ,
Elastic constants of 20% Pu-containing MOX sintered pellet were measured by ultrasonic pulse echo method as a function of porosity and O/M ratio. In addition, the effects of O/M ratio on elastic constants and its atomic scale mechanism were investigated based on the modeling by first-principle calculation which was performed on Ce-O system as a surrogate material of MOX. Measured Young's and shear moduli decreased linearly as the porosity increased in the range from 5% to 15%, where as poison's ratio remained almost constant. Young's and shear moduli of non-stoichiometric samples (O/M = 1.973 and 1.963) decreased slightly from stoichiometric sample (O/M = 2) by less than 5%, which was in a fairly good agreement with first-principle calculation on Ce-O system. Computational results by first-principle calculation indicated that O/M ratio effect on Young's modulus was dominated by the contribution of chemical lattice expansion.
, MOX and PuOKato, Masato; Matsumoto, Taku; Uno, Hiroki*; Sunaoshi, Takeo*; Uchida, Teppei; Komeno, Akira
no journal, ,
no abstracts in English
Morioka, Tatsuya; Sawazaki, Hiromasa; Uchida, Takenobu; Sato, Takeshi; Nakamura, Yoshihide; Shiotani, Hiroki; Kunogi, Kosuke
no journal, ,
Thermal natural convection occurred in Ar gas region between the inner and outer casing of the sodium pump in the past, which induces asymmetric circumferential temperature distribution on the casings. This thermal effect causes the contact of the pump shaft with the lower hydrostatic bearing, which places the bearing at risk for damage. This phenomenon strongly appears in long size pumps of sodium fast reactors. To prevent this risk for Monju primary sodium pump, convection prevention plates are installed between the inner and outer casing of the pump. Monju plant data indicates the plates decrease the circumferential temperature difference, and then no contact arose between the pump shaft and the bearing.
Sato, Takeshi; Sawazaki, Hiromasa; Morioka, Tatsuya; Uchida, Takenobu; Nakamura, Yoshihide; Shiotani, Hiroki; Okawachi, Yasushi
no journal, ,
In Monju, it is important to detect and respond to hydrogen concentration changes in secondary sodium at an early stage, before any water leakage from the steam generator heat transfer tube expands. For that purpose, it is necessary to understand the hydrogen concentration during normal operation. In this report, we estimated, using the purification efficiency evaluation of the cold trap reported at the fall programs of 2016, the amount of diffused hydrogen from the characteristic test data of 1995 and evaluated the hydrogen concentration in the secondary sodium during normal operation.
Shiotani, Hiroki; Sawazaki, Hiromasa; Nakamura, Yoshihide; Sato, Takeshi; Uchida, Takenobu; Arai, Masanobu
no journal, ,
We are evaluating operating data of about 20 years (Evaluation of "Monju Research Plan") through the collaboration of both older and younger engineers. In this study, we will propose the use of information technologies and/or statistics tools in future evaluation to make the data treatment in an effective and efficient manner. In addition to that, we will also present a vision for supporting and cooperating technical tradition and knowledge discovery, etc. nuclear engineers by machine learning technologies toward the commercialization of fast reactor cycle systems.
Sawazaki, Hiromasa; Nakamura, Yoshihide; Sato, Takeshi; Morioka, Tatsuya; Uchida, Takenobu; Shiotani, Hiroki; Kisohara, Naoyuki
no journal, ,
We are evaluating operating data of about 20 years (Evaluation of "Monju" Research Plan) Now, In this presentation, We extract the facilities that can be evaluated on the "Monju" research plan and report the result of selecting the evaluation items. In addition, some of the evaluations were found to be possible from another viewpoint. We added them as evaluation items, and we will add evaluation items in order and evaluate them in the future as they become obvious in the future. In addition, we are currently reviewing the results of the research and development on "Monju" including "Monju" Research Plan within the JAEA, and review the evaluation items and the plan itself as necessary.
Uchida, Takenobu; Sawazaki, Hiromasa; Morioka, Tatsuya; Sato, Takeshi; Nakamura, Yoshihide; Shiotani, Hiroki; Okawachi, Yasushi
no journal, ,
The reactor cavity and Primary room Heat Transfer System (PHTS) cells of FBR are designated as water prohibited area to prevent sodium-water reaction phenomena. In Monju, fluorocarbon is used as a refrigerant instead of water refrigerants for Reactor Building (R/B) Heating, Ventilation, and Air Conditioning (HVAC). R/B HVAC chiller system using fluorocarbon is characteristic equipment for FBR, and there is no example in light water reactors. In this study, we evaluated the running performance of R/B HVAC Chiller System by using about 20 years Plant data as an Evaluation of "Monju" Research Plan.
Nakamura, Yoshihide; Sawazaki, Hiromasa; Morioka, Tatsuya; Uchida, Takenobu; Sato, Takeshi; Shiotani, Hiroki; Kisohara, Naoyuki
no journal, ,
With the liquid metal sodium cooled fast reactor, sodium has to be maintained and managed at a high purity to prevent the channel blockage by the precipitation of impurities and the material corrosion with sodium. At Monju, primary heat transport system, secondary heat transport system, and ex-vessel fuel storage tank sodium cooling system are corresponding to this clean-up system. We evaluate the sodium purity control condition of these facilities for more than 20 years by the measurement of the plugging meter and chemical analysis, and confirm that we could maintain the purity with a value lower enough than the management targeted value.
Matsunaga, Keita*; Aizawa, Koki*; Ogawa, Hiroki; Utsugi, Mitsuru*; Yoshimura, Ryokei*; Yamazaki, Kenichi*; Uchida, Kazunari*
no journal, ,
no abstracts in English
