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Hatano, Toshihisa; Kuroda, Toshimasa*; Barabash, V.*; Enoeda, Mikio
Journal of Nuclear Materials, 307-311(2), p.1537 - 1541, 2002/12
Times Cited Count：4 Percentile：29.25(Materials Science, Multidisciplinary)no abstracts in English
Uwaba, Tomoyuki; ;
JNC TN9400 2000-006, 50 Pages, 1999/11
JNC-TN9400-2000-006.pdf:2.17MB
In the fast reactor the swelling of the fuel cladding occur due to the irradiation. Under the irradiation, the temperature gradient of the cladding through the direction of its thickness causes the swelling gradient and this will cause the secondary stress. In this study, we analyzed this secondary stress using the finite element model of the irradiation induced deformation of the cladding by FINAS code. The result of this analysis is summarized as follows. (1)The secondary stress is mainly caused by the gradient of the incubation period of the swelling, The secondary stress becomes very small at the end of irradiation due to the relieving of the stress by the irradiation creep deformation accelerated by the swelling. (2)The calculated maximum stress including the secondary stress under the irradiation is compared with the design value of the ultimate tensile strength for PNC316 for trial. The calculated value are lower than the design value. (3)The effect of the swelling accelerated by the stress is analyzed using the correlation between the swelling and the stress. The result shows that the increasing of the secondary stress due to the acceleration of the swelling is very small because the irradiation creep deformation relieves the stress more effectively by the acceleration of the irradiation creep rate due to the swelling.
Takachi, Kazuhiko; Suzuki, Hideaki*
JNC TN8400 99-041, 76 Pages, 1999/11
The buffer material is expected to maintain its low water permeability, self-sealing properties, radionuclides adsorption and retardation properties, thermal conductivity, chemical buffering properties, overpack supporting properties, stress buffering properties, etc. over a long period of time. Natural clay is mentioned as a material that can relatively satisfy above. Among the kinds of natural clay, bentonite when compacted is superior because (1)it has exceptionally low water permeability and properties to control the movement of water in buffer, (2)it fills void spaces in the buffer and fractures in the host rock as it swells upon water uptake, (3)it has the ability to exchange cations and to adsorb cationic radioelements. In order to confirm these functions for the purpose of safety assessment, it is necessary to evaluate buffer properties through laboratory tests and engineering-scale tests, and to make assessments based on the ranges in the data obtained. This report describes the procedures, test conditions, results and examinations on the buffer material of unconfined compression tests, one-dimensional consolidation tests, consolidated-undrained triaxial compression tests and consolidated-undrained triaxial creep tests that aim at getting hold of static mechanical properties. We can get hold of the relationship between the dry density and tensile stress etc. by Brazillian tests, between the dry density and unconfined compressive strength etc. by unconfined compression tests, between the consolidation stress and void ratio etc. by one-dimensional consolidation tests, the stress pass of each effective confining pressure etc. by consolidated-undrained triaxial compression tests and the axial strain rate with time of each axial stress etc. by consolidated-undrained triaxial creep tests.
; Hirakawa, Yasushi; Kano, Shigeki; Yoshida, Eiichi
PNC TN9410 98-048, 56 Pages, 1998/03
Planar specimens of functionally gradient material (FGM) for thermal stress relaxation in fast reactor environment were formed and evaluated. FGMs of Al
O
-SUS316L system and YO-SUS316L system were deposited on SUS316L substrates by low pressure plasma spraying. The deposited coatings with 6 layers in which the ratio of ceramics/SUS316FR changes from 0 to 100% by 20% were successfully formed. Cross-sectional observation of the coatings showed no cracks and the hardness in the coating increased continuously from the substrate to the surface. From the results of X-ray diffraction, there were no changes in the structure of SUS316L and YO between the powder and the coating. On the contrary, in the case of AlO, 
- AlO phase was detected in the coating formed from 
_
_
$ powder. The specimens were exposed in liquid sodium at 823K or 923K for 3.6Ms(1000h). The coatings were damaged with many cracks in liquid sodium. It was revealed that the bonding strength between the sprayed particles were not sufficient. To improve the stability in liquid sodium, another specimens were formed with changing the chamber pressure during deposition. From the microstructural inspections of the specimens, the coating formed at higher chamber pressure showed less porosity.
CKikuchi, Kenji; H.J.Penkalla*; Nishi, Hiroshi
Nihon Kikai Gakkai Rombunshu, A, 63(613), p.2032 - 2037, 1997/09
no abstracts in English
Mori, Koji*; Neyama, Atsushi*; *; Nishimura, Kazuya*
PNC TJ1458 97-003, 179 Pages, 1997/02
None
H.J.Penkalla*; Kikuchi, Kenji
Nihon Kikai Gakkai Rombunshu, A, 62(593), p.162 - 167, 1996/01
no abstracts in English
Ito, Masayuki; *; *
Nihon Gomu Kyokai-Shi, 69(1), p.62 - 67, 1996/00
no abstracts in English
; *; ; Yoshida, Eiichi;
PNC TN9410 94-261, 143 Pages, 1994/06
In this study, tensile, creep and relaxation test in air were performed in order to examine the mechanical properties of Mod.9Cr-1Mo steel which is a candidate material for once throuth type steam generator of large scale fast breeder reactor. Tested materials were plate(12mmt) simulating heat exchenger tube and heat exchenger tube of Mod.9Cr-1Mo steel and 9Cr-2Mo steel was also tested as reference material. Results obtained are summarized as follows. (1)Tensile properties (a)Ultimate tensile strength and 0.2% yield strength of Mod.9Cr-1Mo steels were higher than the tentative Su and Sy values of the design allowable stress in the test temperature below 600C. (b)Ultimate tensile strength of Mod.9Cr-1Mo steels plate and tube were higher than that of 9Cr-2Mo Steels. (3)The difference in ultimate tensile strength and 0.2% yield strength between steel plate and tube could not be found in these tests. (2)Creep properties (a)Creep rupture strength of Mod.9Cr-1Mo steel plate and tube was higher than the tentative S
value of the design creep-rupture stress intensity at 500
600C, and this tendency is significant in the range of longer rupture time. (b)For the relation between steady creep rate and creep rupture time, steady creep rates obtained in this study coincided well with the 
of tentative creep strain equation. (c)Creep rupture strength of Mod.9Cr-1Mo steel plate and tube was higher than that of 9Cr-2Mo steel. (3)Relaxation properties (a)In the strain range of 0.10.5%, stress rapidly relaxed during the short hold time, and stress relaxation tended to be saturate beyond 50hours. These relaxation stresses became large in higher temperature and higher strain level. (b)Stress relaxation behavior was predicted approximately by tentative creep equation of Mod.9Cr-1Mo steel. The analysis of these test results is continued to develop of evaluation method of material strength.
Watanabe, Ryuzo*; *
PNC TJ9601 94-003, 87 Pages, 1994/03
This report is the PNC contract research for fiscal year of 1993 titled "Formation of Ti/SUS/Mo graded layer by slurry dipping." Fuel sheath material for FBR is used under a severe enviroment. The life of conventionally used SUS316 is known to be only two years. The development of long-life core material having high temperature strength, radiation resistance and anti-corrosion property is now essential. To create a super-long-life core materials for FBR it seems promising to employ the concept of functionally gradient material, in which these different materials are configurated with grading : as base material is used SUS316 stainless steel, the inner wall is made of Ti for the radiation resistant and anti-corrosion property with graded intermediate layers towards the base metal and the outer shell is the graded Mo layer for the corrosion resistance against liquid sodium. The shape of the core tube is a long cylindrical tube and its dimensions are 8.5mm in outer diameter, about 2m in length, shell thickness is 0.5mm and the thickness of the gradient layer is about 0.1mm. However, we have not yet acquired sufficient techniques to realize such shape and dimmensions, and the investigation is planned to get basic informations on the processing of the core materials with graded structures. Slurry dipping has been employed for forming a graded layer on curved inner and outer surfaces. And it is indispensable that the graded layers have showed sufficient thermal-stress relief function, as well as good bonding capability. In this year (FY 1993), the formation of the graded inner layer of Ti/SUS316 by slurry dipping was investigated. The formation procedure is briefly mentioned here as follows. Cylindrical green compacts of SUS304 stainless steel powder was prepared by die compaction and CIP as a substrate for slurry dipping. A coarse Ti powder was suspended in ethanol and milled by tumbler ball mill to get a slurry having an appropriate viscosity for dipping. The ...
Ito, Masayuki
DEI-92-113, p.57 - 62, 1992/12
no abstracts in English
Kikuchi, Kenji; Kaji, Yoshiyuki
Engineering Fracture Mechanics, 40(4-5), p.749 - 755, 1991/00
Times Cited Count：0 Percentile：0.02(Mechanics)no abstracts in English
*; Udagawa, Akira; *; Hama, Yoshimasa*; Seguchi, Tadao
EIM-90-126, p.11 - 18, 1990/12
no abstracts in English
C*
PNC TN9410 90-086, 47 Pages, 1990/05
Since stainless steels like SUS 304 and SUS 316 tend to be carburized in sodiun, the grain boundary near surface may be degraded due to carbides precipitation. In order to clarify the effect of the grain boundary degradation upon creep fatigue strength, long term creep fatigue tests of SUS304 stainless steel were performed in carburized sodium, 0btained results are summarized as follows: (1)Creep fatigue life in carburized sodium was nearly equal to that in air, in spite of the fact that severe carburization and carbides precipitation on grain boundary were observed on tested specimen surface. (2)Creep fatigue life calculated using usual linear damage summation rule showed good agreement with experimental results, (3)It was revealed that crack initiation life in carburized sodium was almost the same as that in air, although crack initiated on degraded grain boundary in carburized sodium. (4)The above fact supplies an evidence to justify the concept that creep fatigue crack initiation life in sodium is longer than 1/20 of failure life obtained using small specimens in air, which is basic assumption of our creep fatigue evaluation method. It is conjectured from this study that FBR grade SUS316 stainless steel will show almost the same creep fatigue life as that in air, however, a few creep fatigue tests of FBR grade SUS316 in carburized sudium will be necessary to clarify this conjecture.
*
PNC TN9410 90-093, 68 Pages, 1990/01
The authors have conducted a series of axial and torsional biaxial fatigue/creep-fatigue tests with :304 stainless steel at 550 C and obtained the following conclusions, (1)A fatigue life under nonproportional loading reduces to 1/2-1/3 of that under proportional loading. (2)The life reduction under nonproportional loading can be accouted for by path-dependent Mises type equivalent strain range. In this report, the results of creep-fatigue tests under proportional and nonproportional loading are examined. The following results were obtained. (1)A creep-fatigue life under nonproportional loading reduces to 1/2-1/5 of that under proportional loading. (2)Stress relaxation occurs towards origin proportionally (to the point where axial and torsional loads are zero) even under nonproportional creep-fatigue loading. (3)A creep-fatigue life under nonproportional loading can resonably be evaluated based on the fatigue properties and the creep properties obtained under uniaxial loading conditions, using the path dependent Mises type equivalent strain range and Mises equivalent stress.
Nucl.Eng.Des., 97, p.279 - 296, 1986/00
Times Cited Count：2 Percentile：32.47(Nuclear Science & Technology)no abstracts in English
