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Yoshida, Ryoichiro; Yamane, Yuichi; Abe, Hitoshi
Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.408 - 414, 2019/09
In a criticality accident, it is known that some kinds of radiolysis gases are generated mainly due to kinetic energy of fission fragments. Hydrogen gas (H
) is one of them, which is able to initiate explosion. The rate of H generation and its total amount can be estimated from the number of fission per second if its G value is known. In this study, it was tried to estimate G value of hydrogen gas (G(H)) by using the H concentration measured as time-series data in Transient Experiment Critical Facility (TRACY) which was carried out by Japan Atomic Energy Agency. There was time lag in the measured H concentration from its generation. To overcome those problems, measured profile of H concentration was reproduced based on a hypothetical model and its total amount was evaluated. Based on the model, the obtained G(H) was 1.2.
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.
Kokusen, Junya; Seki, Masakazu; Abe, Masayuki; Nakazaki, Masato; Kida, Takashi; Umeda, Miki; Kihara, Takehiro; Sugikawa, Susumu
JAERI-Tech 2005-004, 53 Pages, 2005/03
JAERI-Tech-2005-004.pdf:5.92MB
This report presents operating records of dissolution of uranium dioxide and concentration of uranyl nitrate solution and acid removal, which have been performed from 1994 through 2003, for the purpose of feeding 10% and 6% enriched uranyl nitrate solution fuel to Static Experimental Critical Facility(STACY) and Transient Experimental Critical Facility(TRACY) in Nuclear Fuel Safety Engineering Facility(NUCEF).
Watanabe, Shoichi; Yamamoto, Toshihiro; Miyoshi, Yoshinori
Transactions of the American Nuclear Society, 91, p.431 - 432, 2004/11
Temperature effect is a main factor which affects the transient characteristics at a criticality accident. A series of reactivity effects due to changes in fuel temperatures were measured for two kinds of STACY heterogeneous lattice configurations. The core was composed of LWR-type fuel rod array and low-enriched uranyl-nitrate-solution concerning the dissolver of the reprocessing facility for LWR spent fuel. The critical solution heights at various solution temperatures were measured. From the change of the critical water height with fuel temperature, the reactivity effect was evaluated by a critical-solution-level worth method. The temperature effect was also calculated by using SRAC and the transport calculation code TWODANT. The experimental value was estimated to be -2.0 cent/
C for the case "2.1cm-pitch", and -2.5 cent/C for the case "1.5cm-pitch". The calculated results gave agreement with the experiments within 
10%.
Haga, Takahisa*; Gunji, Kazuhiko; Fukaya, Hiroyuki; Sonoda, Takashi; Sakazume, Yoshinori; Sakai, Yutaka; Niitsuma, Yasushi; Togashi, Yoshihiro; Miyauchi, Masakatsu; Sato, Takeshi; et al.
JAERI-Tech 2004-005, 54 Pages, 2004/02
JAERI-Tech-2004-005.pdf:2.06MB
Criticality experiments using uranyl nitrate solution fuel are being conducted at STACY (the Static Experiment Critical Facility) and TRACY (the Transient Experiment Critical Facility) in NUCEF (the Nuclear Fuel Cycle Safety Engineering Research Facility). Chemical analyses of the solution have been carried out to take necessary data for criticality experiments, for treatment and control of the fuel, and for safeguards purpose at the analytical laboratory placed in NUCEF. About 300 samples are analyzed annually that provide various kinds of data, such as uranium concentration, isolation acid concentration, uranium isotopic composition, concentration of fission product (FP) nuclides, tri-butyl phosphoric acid (TBP) concentration, impurities in the solution fuel and so on. This report summarizes the analytical methods and quality management of the analysis for uranyl nitrate solution relating to the criticality experiments.
Tonoike, Kotaro; Miyoshi, Yoshinori; Okubo, Kiyoshi
Journal of Nuclear Science and Technology, 40(4), p.238 - 245, 2003/04
Times Cited Count：2 Percentile：19(Nuclear Science & Technology)The reactivity effect of neutron interaction between two identical units containing low enriched (10% 
enrichment) uranyl nitrate solution was measured in the STACY. The unit has 350mm of thickness and 690mm of width and distance between those two units was adjustable from 0mm to 1450mm. Condition of the solution was about 290gU/L in uranium concentration, about 0.8N in free nitric acid molarity, 2427C in temperature and about 1.4g/cm
in solution density. The reactivity effect was estimated from variation of critical solution level from 495mm to 763mm depending on the core distance. The reactivity effect was also evaluated by the solid angle method and a computational method using the continuous energy Monte Carlo code MCNP-4C and the nuclear data library JENDL3.2. Comparison of those estimations is presented.
Yamane, Yuichi; Miyoshi, Yoshinori; Watanabe, Shoichi; Yamamoto, Toshihiro
Nuclear Technology, 141(3), p.221 - 232, 2003/03
Times Cited Count：5 Percentile：36.81(Nuclear Science & Technology)no abstracts in English
measurement on low enriched uranyl nitrate solution with single unit cores (600
, 280T, 800) of STACYTonoike, Kotaro; Miyoshi, Yoshinori; Kikuchi, Tsukasa*; Yamamoto, Toshihiro
Journal of Nuclear Science and Technology, 39(11), p.1227 - 1236, 2002/11
Times Cited Count：21 Percentile：77.35(Nuclear Science & Technology)Kinetic parameter of low enriched uranyl nitrate solution was measured by the pulsed neutron source method in the STACY. This measurement was repeated systematically over several uranium concentrations from 193.7 gU/
to 432.1 gU/. Used core tanks were two cylindrical tanks whose diameters are 600 mm and 800 mm and one slab tank which has 280 mm thickness and 700 mm width. In this report, experimental data such as solution conditions, critical solution level for each solution condition, subcritical solution levels where measurements were conducted, measured decay time constants of prompt neutron and extrapolated values are described as well as basic principle of the pulsed neutron source method. values were evaluated also by computation with the diffusion code CITATION in SRAC and the nuclear data library JENDL 3.2. Both experimental and computational values show good agreement.
Aizawa, Eiju; Ogawa, Kazuhiko; Sakuraba, Koichi; Tsukamoto, Michio; Sugawara, Susumu; Takeuchi, Masaki*; Miyauchi, Masakatsu; Yanagisawa, Hiroshi; Ono, Akio
JAERI-Tech 2002-031, 120 Pages, 2002/03
JAERI-Tech-2002-031.pdf:4.32MB
TRACY (Transient Experiment Critical Facility) in NUCEF (Nuclear Safety Research Facility) is the pulse-type critical facility using uranyl nitrate solution which can carry out various supercritical experiments changing reactivity addition up to 3$.TRACY achieved its first criticality on 20th December 1995,and transient operations have been conducted Since1996.This report summarizes the operation data of 176 experiments from the first criticality to FY2000.
Uchida, Masaaki
IAEA Regional Workshop on Accident Management and Emergency Response for Research Reactors, 11 Pages, 2002/00
no abstracts in English
Spectrochimica Acta, Part A, 53(4), p.501 - 507, 1997/00
no abstracts in English
Hirata, Masaru
JAERI-Research 96-033, 16 Pages, 1996/06
JAERI-Research-96-033.pdf:0.69MB
no abstracts in English
; Takahashi, Yoshihisa
Journal of Nuclear Science and Technology, 33(2), p.147 - 151, 1996/02
Times Cited Count：1 Percentile：14.44(Nuclear Science & Technology)no abstracts in English
; ;
Spectrochimica Acta, Part A, 52, p.149 - 156, 1996/00
no abstracts in English
; ;
Applied Spectroscopy, 49(2), p.216 - 219, 1995/00
Times Cited Count：14 Percentile：73.04(Instruments & Instrumentation)no abstracts in English
(NO
);M=Cs,Rb,K,NH
);
Spectrochimica Acta, Part A, 51(3), p.309 - 318, 1995/00
no abstracts in English
*; Arakawa, Takuya*; Okuno, Hiroshi
JAERI-Data/Code 94-018, 36 Pages, 1994/12
JAERI-Data-Code-94-018.pdf:1.09MB
no abstracts in English
Okuno, Hiroshi; Nomura, Yasushi
JAERI-Data/Code 94-014, 33 Pages, 1994/10
JAERI-Data-Code-94-014.pdf:0.98MB
no abstracts in English
Spectrochimica Acta, Part A, 35A(11), p.1283 - 1288, 1979/00
no abstracts in English
J.Coord.Chem., 8, p.35 - 39, 1978/00
Times Cited Count：12no abstracts in English
