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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%.
Tonoike, Kotaro; Miyoshi, Yoshinori; Okubo, Kiyoshi
Journal of Nuclear Science and Technology, 40(4), p.238 - 245, 2003/04
Times Cited Count：2 Percentile：18.9(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：36.77(Nuclear Science & Technology)no abstracts in English
Tabata, Toshio; Nagao, Yoshiharu; Komukai, Bunsaku; Naka, Michihiro; Takeda, Takashi*; Fujiki, Kazuo
JAERI-Tech 2002-100, 108 Pages, 2003/01
JAERI-Tech-2002-100.pdf:4.44MB
After the investigation of the new core arrangement for the JMTR reactor in order to enhance the fuel burn-up and consequently extend the operation period, the "improved LEU core" that utilized 2 additional fuel elements instead of formerly installed reflector elements, was adopted. This report describes the results of the thermal-hydraulic analysis of the improved LEU core as a part of safety analysis for the licensing. The analysis covers steady state, abnormal operational transients and accidents, which were described in the annexes of the licensing documents as design bases events. Calculation conditions for the computer codes were conservatively determined based on the neutronic analysis results and others. The results of the analysis, that revealed the safety criteria were satisfied on the fuel temperature, DNBR and primary coolant temperature, were used in the licensing. The operation license of the JMTR with the improved LEU core was granted in March 2001, and the reactor operation with new core started in November 2001 as 142nd operation cycle.
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：77.32(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.
Yamamoto, Kazuyoshi; Watanabe, Shukichi; Nagatomi, Hideki; Kaminaga, Masanori; Funayama, Yoshiro
JAERI-Tech 2002-034, 40 Pages, 2002/03
JAERI-Tech-2002-034.pdf:1.97MB
JRR-4, a swimming-pool type research reactor with a thermal power of 3.5MW, attained criticality in July 1998, after replacing its 90% enrichment fuel with a 20% enrichment fuel under the Reduced Enrichment Program. As a part of the program, safety analysis on thermo-hydraulics of the reactor core was conducted on cases including single channel blockage accident. With the conclusion that a certain margin on thermo-hydraulics was necessary, investigation and experiments were carried out with an aim to increase the core flow rate. To increase the core flow, it was carried out to reduce the bypass flow in the core and to increase the primary coolant flow rate from 7m/min to 8m/min. After flow measurements using a mock-up fuel element, flow velocity of the fuel channel was determined as 1.45m/s as opposed to the designed value of 1.44m/s, and the ratio of core flow to total flow was 0.88, exceeding the value 0.86 used for the safety analysis.This report describes the JRR-4 core flow increase plan as well as the results of the channel flow rate measurement
Nakajima, Ken
Journal of Nuclear Science and Technology, 38(12), p.1120 - 1125, 2001/12
no abstracts in English
Nakajima, Ken; ; ; ; *; Sakuraba, Koichi; Ono, Akio
PHYSOR 96: Int. Conf. on the Physics of Reactors, 4, p.L83 - L92, 1996/00
no abstracts in English
; Yamane, Tsuyoshi
JAERI-Research 95-081, 32 Pages, 1995/11
JAERI-Research-95-081.pdf:1.28MB
no abstracts in English
Yanagisawa, Kazuaki;
Journal of Nuclear Science and Technology, 32(10), p.981 - 988, 1995/10
Times Cited Count：1 Percentile：17.52(Nuclear Science & Technology)no abstracts in English
Yanagisawa, Kazuaki;
Journal of Nuclear Science and Technology, 32(9), p.889 - 897, 1995/09
Times Cited Count：2 Percentile：28.04(Nuclear Science & Technology)no abstracts in English
; Yamane, Tsuyoshi; Sasa, Toshinobu
JAERI-Data/Code 94-013, 17 Pages, 1994/10
JAERI-Data-Code-94-013.pdf:0.77MB
no abstracts in English
Yanagisawa, Kazuaki; ; Horiki, Oichiro; Soyama, Kazuhiko; Ichikawa, Hiroki; Kodaira, Tsuneo
Journal of Nuclear Science and Technology, 30(8), p.741 - 751, 1993/08
Times Cited Count：4 Percentile：44.86(Nuclear Science & Technology)no abstracts in English
Yanagisawa, Kazuaki; ; Horiki, Oichiro; Soyama, Kazuhiko; Ichikawa, Hiroki; Kodaira, Tsuneo
Journal of Nuclear Science and Technology, 29(3), p.233 - 243, 1992/03
no abstracts in English
and 
(
) counting using a CsI(T1) scintillatorUsuda, Shigekazu; Abe, Hitoshi
Nuclear Instruments and Methods in Physics Research A, 321, p.242 - 246, 1992/00
Times Cited Count：17 Percentile：81.26(Instruments & Instrumentation)no abstracts in English
Yanagisawa, Kazuaki
JAERI-M 91-152, 195 Pages, 1991/10
no abstracts in English
Yanagisawa, Kazuaki; ; ; Horiki, Oichiro; Soyama, Kazuhiko; Ichikawa, Hiroki; Kodaira, Tsuneo; Yamahara, Takeshi
Proc. of the 3rd Asian Symp. on Research Reactor, p.391 - 398, 1991/00
no abstracts in English
Nakamura, Hiroo; Tobita, Kenji; Hirayama, Toshio; Koide, Yoshihiko; Arai, Takashi; Kuriyama, Masaaki; Kubo, Hirotaka; Kusama, Yoshinori; Sugie, Tatsuo; Sugihara, Masayoshi; et al.
Fusion Technology, 18, p.578 - 582, 1990/12
no abstracts in English
Okuno, Hiroshi; Komuro, Yuichi
JAERI-M 90-058, 174 Pages, 1990/03
no abstracts in English
Yamane, Tsuyoshi; ; Akino, Fujiyoshi; Kaneko, Yoshihiko
Journal of Nuclear Science and Technology, 27(2), p.122 - 132, 1990/02
no abstracts in English
