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Abe, Yuta; Otaka, Masahiko; Sekiya, Naoki*; Makuuchi, Etsuyo*
Hihakai Kensa, 71(2), p.69 - 74, 2022/02
no abstracts in English
Ozu, Akira; Takase, Misao*; Haruyama, Mitsuo; Kurata, Noritaka*; Kobayashi, Nozomi*; Kureta, Masatoshi; Nakamura, Tatsuya; To, Kentaro; Sakasai, Kaoru; Suzuki, Hiroyuki; et al.
Nuclear Instruments and Methods in Physics Research A, 798, p.62 - 69, 2015/10
Times Cited Count:2 Percentile:17.52(Instruments & Instrumentation)The light transport properties of scintillator light inside alternative He-3 neutron detector modules using scintillator sheets have been investigated by a ray-tracing simulation code. The detector module consists of a light-reflecting tube, a thin rectangular ceramic scintillator sheet laminated on a glass plate, and two photo-multiplier tubes (PMTs) mounted at both ends of the detector tube. The light induced on the surface of the scintillator sheet via nuclear interaction between the scintillator and neutrons are detected by the two PMTs. The light output of various detector modules in which the scintillator sheets are installed with several different arrangements were examined and evaluated in comparison with experimental results. The results derived from the simulation reveal that the light transport property is strongly dependent on the arrangement of the scintillator sheet inside the tube and the shape of the tube.
Neudatchin, S. V.; Takizuka, Tomonori; Shirai, Hiroshi; Fujita, Takaaki; Isayama, Akihiko; Kamada, Yutaka; Koide, Yoshihiko; Dnestrovskij, Y. N.*
JAERI-Research 2001-056, 32 Pages, 2001/12
no abstracts in English
; kasahara, Naoto; ; ; Kamide, Hideki
JNC TN9400 2000-010, 168 Pages, 2000/02
Thermal striping is significant issue of the structural integrity, where the hot and cold fluids give high cycle fatigue to the structure through the thermal stress resulted from the time change of temperatur distibution in the structure. In the sodium cooled fast reactor, temperature change in fluid easily transfers to the structure because of the high thermal conductivity of the sodium. It means that we have to take care of thermal striping, The thermal striping is complex phenomena between the fluid and structure engineering fields. The investigations of thermal striping are not enough to evaluate the integrity directly. That is the fluctuation intensity at the structure surface is assumed to be temperature difference between source fluids (upstream to the mixing region) as the maximum value in the design. 0therwise, the design conditions are defined by using a mockup experiment and large margin of temperature fluctuation intensity. Furthermore, such evaluation manners have not yet been considered as a design rule. Transfer mechanism of temperature fluctuation from fluid to structure has been investigated by the authors on the view points of the fluid and structure. Attenuation of temperature fluctuation was recognized as a dominant factor of thermal fatigue. We have devdoped a numerical analysis system which can evaluate thermal fatigue and crack growth with consideration of the attenuation of temperature fluctuation in fluid, heat transfer, and structure. This system was applied to a real reactor and the applicability was confirmed. Further verification is planned to generalize the system. For the higher cost performance of the fast reactor, an evaluation rule is needed, which can estimate thermal loading with attenuation and can be applied to the design. An idea of the rule is proposed here. Two methods should be prepared; one is a precise evaluation method where mechanism of attenuation is modeled, and the other is simple evaluation method where ...
Neudatchin, S. V.; Takizuka, Tomonori; Shirai, Hiroshi; Fujita, Takaaki; Isayama, Akihiko; Koide, Yoshihiko; Kamada, Yutaka
JAERI-Research 99-063, p.38 - 0, 1999/11
no abstracts in English
J.S.Koog*; Sakasai, Akira; Koide, Yoshihiko; Shirai, Hiroshi; Kamada, Yutaka; Fukuda, Takeshi; Yoshino, Ryuji; JT-60 Team
Review of Scientific Instruments, 70(1), p.372 - 374, 1999/01
Times Cited Count:3 Percentile:33.24(Instruments & Instrumentation)no abstracts in English
Kado, Masataka; Nagashima, Keisuke; Sagisaka, Akito*; Hasegawa, Noboru; ; Kato, Yoshiaki
Inst. Phys. Conf. Ser., (159), p.293 - 296, 1999/00
no abstracts in English
Maruyama, Tadashi; ; ; Onose, Shoji;
PNC TN9410 97-077, 177 Pages, 1997/07
Postirradiation examinations of JOYO MK-II control rods have been carried out since 1983, where 16 subassemblies with total 110 absorber pins of initial load to the fifth reload control rods have been subjected to a number of both non-destructive and destructive examinations. In the course of postirradiation examinations, a cracking of cladding tube was found in the total 15 absorber pins in five control assemblies. This paper indicates the results of postirradiation examinations and analysis of absorber pin performance using CORAL code to elucidate the cause of absorber pin cracking in JOYO MK-II control rods. No crack was found in absorber pins whose maximum burnup was lower than 39 10 cap/m, whereas all the cracked pins had burnup of higher than 43 10 cap/m with the initial gap between BC pellet and cladding larger than 0.44 mm. The cracks were found at around positions corresponding to the lowest BC pellet in the stack. The ceramography analysis indicated that BC pellet exhibited extensive cracking and a part of gap between pellet and cladding closed. The cladding deformation had an ovality and the cracks tended to occur at the shorter diameter side. The cracked surface of absorber pin was of a typical grain boundary fracture. The result of He analysis for the cladding material indicated a substantial amount of He accumulation at the inner surface of cladding, but the bulk He content was not anomalously high compared with those in the neutron irradiated stainless steels. TEM observation indicated He bubbles was not clearly found in the as-irradiated cladding material. The cause of cladding failure was attributed to the ACMI where the gap closure due to relocation of BC pellet took place from early times of irradiation. The code analysis by CORAL indicated that the cladding strain due to ACMI was not fully absorbed by the irradiation creep and that the plastic strain became large enough to ...
Isozaki, Kazunori;
PNC TN9410 97-069, 134 Pages, 1997/07
Hyougo-ken southern earthquake broke out in 1997/01/17. The Atomic Energy Safety Co㎜ission considered reasonable of the design guide for seismic design. And the Science and Technology Agency(STA) required reevaluation of atomic power facilities built by old design guide according to the new seismic design guide. JOYO obtained the construction license in 1970/02. Heat transport system and buildings of JOYO was reevaluated by the new seismic design guide for the MK-III project. So, JOYO was not required reevaluation by STA. But, this evaluation of MK-III was limited to reconstruction area, and the seismic design was reevaluated extensively to confirm earthquake proof characteristics. The structural integrity of buildings and equipments was confirmed by the result of reevaluation by the new seismic design guide. The analysis model conditions were established according to the 1987 and 1991 version of JEAG. This was done by ground investigation result and buildings vaibration test. It was made clear that the analysis model conditions were reasonable and conservative from a technical view point.
Aoto, Kazumi; ; ; ; ; Hirakawa, Yasushi
PNC TN9410 97-076, 29 Pages, 1996/06
This report describes the check of the thermocouple well at the inlet of the intermediate heat exchanger (IHX) of C-loop of the secondary heat tansfer system of the prototype fast breeder reactor Monju, regarding the sodium leak accident of the thermocouple well at the outlet of the IHX of the same loop of the secondary heat transfer system of the same plant Monju. Various tests and inspections were performed to check damages at the part with rapid diameter change of the thermocouple well where stress concentration may occur, and to get the information about the integrity of the welded part between the thermocouple well and the attachment. The thermocouple well, the rapid diameter change part, larger and smaller part, respectively, of the thermocouple well, and welded part between the thermocouple well and the attachments were examined as written below. (1)Accurate measurement of the dimension. (2)Vibration test by tapping the thermocouple well. (3)Non destructive testing at some points. (4)Chemical composition analysis. (5)Microscopic observation of metalogical structure. (6)Detailed observation around the rapid diameter change part. (7)Hardness test. (8)Research on corrosion at the clearance. (9)Structure strength test of the thermocouple well. (10)Bending test of the thermocouple's sheath at high temperature.