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Shibata, Taiju; Kunimoto, Eiji*; Eto, Motokuni*; Shiozawa, Shusaku; Sawa, Kazuhiro; Oku, Tatsuo*; Maruyama, Tadashi*
Journal of Nuclear Science and Technology, 47(7), p.591 - 598, 2010/07
Times Cited Count：10 Percentile：56.06(Nuclear Science & Technology)no abstracts in English
Shibata, Taiju; Eto, Motokuni*; Kunimoto, Eiji*; Shiozawa, Shusaku; Sawa, Kazuhiro; Oku, Tatsuo*; Maruyama, Tadashi*
JAEA-Research 2009-042, 119 Pages, 2010/01
JAEA-Research-2009-042.pdf:26.28MB
For the design of the graphite components in the High Temperature Engineering Test Reactor (HTTR), the graphite structural design code for the HTTR etc. were applied. However, general standard systems for the High Temperature Gas-cooled Reactor (HTGR) have not been established yet. The authors had studied on the technical issues which is necessary for the establishment of a general standard system for the graphite components in the HTGR. The results of the study were documented and discussed at a "Special committee on research on preparation for codes for graphite components in HTGR" at Atomic Energy Society of Japan (AESJ). As a result, "Draft of Standard for Graphite Core Components in High Temperature Gas-cooled Reactor" was established. In this draft standard, the graphite components are classified three categories (A, B and C) in the standpoints of safety functions and possibility of replacement. For the components in the each class, design standard, material and product standards, and in-service inspection and maintenance standard are determined. This draft standard is the first standard in the world which shows the concept of standard for the graphite core components in HTGR.
Kunimoto, Eiji; Shibata, Taiju; Shimazaki, Yosuke; Eto, Motokuni*; Shiozawa, Shusaku; Sawa, Kazuhiro; Maruyama, Tadashi*; Oku, Tatsuo*
JAEA-Research 2009-008, 28 Pages, 2009/06
JAEA-Research-2009-008.pdf:4.6MB
The VHTR is being focused and developed internationally. In Japan, the HTTR of the JAEA is in operation, and research and development for the development of commercial HTGRs are carried out. Nuclear graphites are used for core components of the HTGRs and expansion of irradiation data is necessary when enough irradiation data are not established, because the graphite components in the HTGRs are used at severer condition than that in the HTTR. The necessary database can be established by expansion of existing irradiation data with appropriate interpolation and extrapolation methods. This paper shows the reasonable interpolation and extrapolation method for IG-110 graphite which is used for the HTTR and a major candidate for the VHTR. The interpolation and extrapolation method was developed so as to be general by using the irradiation data of the other graphites. As a result, irradiation properties of the IG-110 graphite were successfully expanded to the VHTR condition for the first time and the irradiation properties being necessary for the design could be developed.
B
CMorohashi, Yuko; Maruyama, Tadashi*; Donomae, Takako; Tachi, Yoshiaki; Onose, Shoji
Journal of Nuclear Science and Technology, 45(9), p.867 - 872, 2008/09
Times Cited Count：11 Percentile：58.97(Nuclear Science & Technology)Maruyama, Tadashi*
JNC TJ4420 2004-001, 76 Pages, 2004/03
JNC-TJ4420-2004-001.pdf:15.02MB
Ion irradiation ezperiment was carried out to elucidate microstructural change of neutron-irradiated B4C. The materials used in this investigation were boron carbides made of carbothermi-reduction method. The specimens were irradiated with helium ions having 15 MeV and 100 to 200 keV, to the fluences of 1
10
to 210
/cm
at temperatures from room temperature to 1000
C. After ion irradiation, the microstructure of specimens was analyzed by transmission electron microscopy (TEM). The difference in maicrostructures disappeared among different BC pellets after ion irradiations. The ion-irradiation by 15 MeV helium ions produced a radiation-induced amorphization in the matrix. A radiation-enhanced precipitation of micro-crystals which consists of Fe-rich composition was observed in the materials irradiated below 800C. High temperature helium ion irradiation created a number of He bubbles which is associated with strain fields. When irradiation temperature was increased to 1000C, extended planer bubbles were formed on the (001) plane of BC, Extremely higher helium irradiation lead to initiation of itragranular clarks. We have also carried out studies of method for measurement of isotopic content was accurately measured when recovery of boron from irradiated BC was higher than 60%. Since ICP-MS is rather cheap and easy to measure isotopic content of materials, we studied the feasibility of using ICP-MS for measurement of 10 B in BC.
Maruyama, Tadashi*; Nagatomo, Jinro*
JNC TJ2410 2004-005, 157 Pages, 2004/03
JNC-TJ2410-2004-005.pdf:6.01MB
From these investigation ,it was recommended that when we make enrichment of noble gases by using adsorption bed of activated charcoals,it is desirable to provide two adsorption beds;one for enrichiment and other for separation of noble gases from Ar base gas.
Maruyama, Tadashi*; Nagatomo, Jinro*
JNC TJ2410 2003-001, 170 Pages, 2003/08
JNC-TJ2410-2003-001.pdf:6.32MB
The results of measurement showed that anomalous breakthrough curves were observed at -180C which is effect of condensation of noble gas. However, the amomalous breakthrough curves was not observed at -170C. It was shown that the activated good performances. The effect of materials propertied on the absorption and the desorption properties is summarized as follows: The longer breakthrough time and the steeper break through curves were obtained as the grain size became smaller and the specific surface area gets larger. Further studies are needed to elucidate effect on enrichment of experimental conditions by varying such as the heating rate,sweep gas velocity,and the onset tempertuer of heating
Maruyama, Tadashi*
JNC TJ4400 2001-007, 169 Pages, 2002/03
JNC-TJ4400-2001-007.pdf:33.79MB
no abstracts in English
Maruyama, Tadashi*; Nagatomo, Jinro*
JNC TJ2410 2001-030, 265 Pages, 2002/02
no abstracts in English
Maruyama, Tadashi*
JNC TJ4420 2001-012, 100 Pages, 2001/03
JNC-TJ4420-2001-012.pdf:15.53MB
no abstracts in English
Maruyama, Tadashi*
JNC TJ4420 99-004, 118 Pages, 2000/03
no abstracts in English
Maruyama, Tadashi*
JNC TJ4420 2000-005, 101 Pages, 2000/03
JNC-TJ4420-2000-005.pdf:3.49MB
no abstracts in English
; Onose, Shoji
Dai-3-Kai Shoshago Shiken Ni Kansuru Nikkan Semina, 0 Pages, 1999/00
None
; Onose, Shoji
Journal of Nuclear Science and Technology, 36(4), p.380 - 385, 1999/00
Times Cited Count：28 Percentile：86.68(Nuclear Science & Technology)None
; Onose, Shoji
Proceedings of International Symposium on Environmental-Conscious Innovative Materials Processing with Advanced Energy Sources (ECOMAP-98), 0 Pages, 1998/00
None
Maruyama, Tadashi; Onose, Shoji; Kaito, Takeji; Horiuchi, Hiroto
Journal of Nuclear Science and Technology, 34(10), p.1006 - 1014, 1997/10
None
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 ...
Nagata, Takako; Maruyama, Tadashi; Onose, Shoji
PNC TN9470 97-001, 52 Pages, 1996/11
In order to extend life of control rods for fast reactors, development of both helium-bonded and sodium-bonded absorber pins with shroud are now under investigation. Also, in development of advanced absorber materials which are alternative materials to B4C, the materials that exhibited better properties in out of pile experiments are needed to do irradiation tests to evaluate applicability as neutron absorber in long life control rods. In irradiation tests of AMIR-8, capsules of two types of helium-bonded and three types of sodium-bonded absorber pins are to be irradiated. In designing these capsules, it is requested that the capsules must possess integrity during irradiation at burnup values of 50 
200 10 cap/m at maximum irradiation temperature of 1200C. In order to satisfy above requirements, the design of capsules was done by adjusting the gap size between absorber and cladding, the loading positions and the volume of plenums. The results of design study indicated that, although a target burnup was limited in some capsules, it was confirmed that the irradiation tests are successfully carried out in the other capsules to meet the object of irradiation tests, thereby numerical values in the design of capsules were able to fix.
Kano, Shigeki; Tachi, Yoshiaki; ; Onose, Shoji; ;
Proceedings of MC'96 International Symposium, 0 Pages, 1996/00
None
Kaito, Takeji; ; Onose, Shoji; ;
IAEA IWGFR Kosokuro Seigyobo Semmonka Kaigi, 0 Pages, 1995/07
no abstracts in English
