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Katsuyama, Jinya; Yamaguchi, Yoshihito; Nemoto, Yoshiyuki; Furuta, Takuya; Kaji, Yoshiyuki
Proceedings of ASME 2022 Pressure Vessels and Piping Conference (PVP 2022) (Internet), 9 Pages, 2022/07
Kanayama, Hideyuki*; Hiyoshi, Noritake*; Ogawa, Fumio*; Kawabata, Mie*; Ito, Takamoto*; Wakai, Takashi
Zairyo, 68(5), p.421 - 428, 2019/05
This study presents creep damage assessment method for Mod. 9Cr-1Mo steel by sampling creep testing with thin plate specimen. Tensile creep rupture tests were performed using three different sizes of specimen under two different test environments to verify the creep testing with the thin plate specimen. Time to rupture of Mod. 9Cr-1Mo steel using three different sizes were almost same. In addition, there was no effect of environment on time to rupture. Pre-damaged thin plate specimens were machined from a bulk specimen's gage section that pre-damage test was performed with. Pre-damage based on life fraction rule were 8%, 16% and 25%. No effect of the process of machining pre-damaged specimen on time to rupture was confirmed by verification tests in same test condition as pre-damage test. Stress acceleration creep rupture tests were performed to estimate creep damage assessment. Creep damage assessment by stress acceleration creep rupture tests was sufficiently accurate estimate. Creep damage assessments by Vickers hardness and lath width were compared with the assessment by stress acceleration creep rupture tests to study applicability of these methods.
Aizawa, Kazuya; Tomimitsu, Hiroshi; Tamaki, Hideki*; Yoshinari, Akira*
Journal of Applied Crystallography, 33(1), p.847 - 850, 2000/06
no abstracts in English
Momma, Yoshio*; *; ; ; ; Aoto, Kazumi
JNC TN9400 2000-044, 22 Pages, 2000/03
JNC-TN9400-2000-044.pdf:1.37MB
ln the past the microstructural observation was mostly applied to understand the materials behavior qualitatively in R&D of the new materials and the life prediction for the fast breeder reactor components. However, the correlation between the changes in properties and microstrutures must be clarified to ensure the structural integrity. Particularly we are interested in the method to correlate the long-term properties and microstructural changes at high temperatures. The current research is to quantify the changes in microstructure of the weld metal for the welded structure of the reactor vessel. ln this research we have conducted creep testing of the weld metals at 823 and 873K up to 37,000h. Two types of the weld metals (16Cr-8Ni-2Mo and 18Cr-12Ni-Mo) were subjected to the creep testing. Based on the areas of the precipitates, the microstructural characterization with time and creep damage was attempted. The creep strength of the 16Cr-8Ni-2Mo weld metal is lower than that of the 18Cr-12Ni-Mo one at higher stresses, shorter times. But there is a trend toward to become similar strength with lower stresses and increasing times. The creep-rupture ductility of the 16Cr-8Ni-2Mo weld metal is superior to that of the 18Cr-12Ni-Mo one. The creep-rupture takes place at the interface of the sigma (
) phases precipitated in the delta (
) ferrites at 823K lower stresses and 873K. The amount of precipitates in the 16Cr-8Ni-2Mo weld metal is smaller than that in the 18Cr-12Ni-Mo one at each temperature and stress. Also it is apparent that the amount of the precipitates is primarily responsible to the decomposition of the phase, because the amount of the residual ferrites measured by the Magne-Gauge reduces with times. Using the Larson-Miller parameter it was possible to correlate the amount of the precipitates linearly with the LMP values.
Kawasaki, Hirotsugu; *
JNC TN9400 2000-018, 37 Pages, 2000/03
JNC-TN9400-2000-018.pdf:1.34MB
The damage evaluation for the vessel model on the cyclic thermal transient loading in sodium were performed by the ultrasonic detection method. The wavelet analysis that was an analysis method of the waveform was applied to detect the micro damage before a sign of the crack initiation. The time-frequency analysis by the wavelet transform was performed to evaluate the ultrasonic parameter for the micro damage. As the results, the ultrasonic echo was analyzed by some mother wavelet, and Gabor wavelet was reasonable. The analysis of ultrasonic echo by Gabor wavelet showed drop of the sound velocity at higher frequency than the peak frequency because of attenuation in the high frequency component. The difference of the peak frequency △fp between B1 and B2 echoes increased with the amount of damage, and △ fp was available as a parameter for the micro damage detection. The correlation between the sound velocity and the micro hardness for the amount of damage was also found, and each method suggested to available alternately. ln this study, it was indicated that an ultrasonic wave characteristic value that can detect damaged state before crack initiation was obtained from the wavelet analysis.
; ; Mizuta, Shunji
JNC TN9400 2000-023, 126 Pages, 2000/02
JNC-TN9400-2000-023.pdf:2.94MB
Modified 316 and 15Cr-20Ni base austenitic stainless steels had been developed by Japan Nuclear Cycle Development lnstitute as the candidate materials for Monju and Demonstration fast breeder reactor. Previously, irradiation creep correlation of modified 316 and 15Cr-20Ni had been evaluated using pressurized tubes irradiated in FFTF/MOTA. 0n the other hand, for other austenitic S.S. developed abroad, it was reported that irradiation creep behavior of fuel pin could not be sufficiently described using results of pressurized tube experiments. ln this study, irradiation creep properties of modified 316 and 15Cr-20Ni fuel pins (MFA-I, 2) irradiated in FFTF were evaluated. And irradiation deformation of MFA-1, 2 fuel pins were estimated using the irradiation creep correlation based on MOTA data. The results are summarized as follows : (1)Irradiation creep compliance B
calculated from MFA-I, 2 data are 5.6
15.0
10
[(I0
n/m
, E>0.1Mev)
(MPa)], Which are larger than B based on MOTA data of 2.26.410 and are within the range of B of other austenitic S.S. abroad. (2)Creep-swelling coupling coefficient D derived from MFA-1, 2 data tend to decrease with increasing swelling rate. And the range of D based on MFA-1, 2 data include values calculated from MOTA data of 3.88.210
[(MPa)] and for other austenitic S.S. abroad. (3)As the result that irradiation creep deformation of MFA-1, 2 fuel pins could be appropriately estimated using the irradiation creep correlation derived from MOTA data, it is considered that the creep, correlation based on MOTA data can be applied to estimation of fuel pin deformation.
Kawasaki, Nobuchika; kasahara, Naoto
PNC TN9410 96-294, 47 Pages, 1996/07
As main components of fast reactors, there are reactor vessels, pipes, heat exchangers, nozzles. In order to keep their structural integrity, the elevated temperature structural design guide evaluates primary stress, strain, and creep-fatigue damage of them. Especially in fast reactors which operate under low pressure and high temperature conditions, creep-fatigue damage is dominant, and limits a design range. For the purpose of extending a design range, author evaluated strength of cylindrical structures by an advanced proposed method based on the generalized elastic follow-up model. Furthermore we studied evaluation accuracy of a method of 'monjyu" and a proposed method, through comparison of thermal transient strength test data with damage calculated by two strength evaluation methods. Results are summarized as follows. (1)An advanced proposed method predicted lower fatigue damage (Df) than a method of 'monjyu'. (However, in structural discontinuities where an elastic follow up is large, a proposed method shows higher damage than a method of 'monjyu'.) (2)An advanced proposed method calculated lower creep damage (Dc) than a method of 'monjyu'. (About 0.7 times lower in a cylindrical structure with a structural discontinuity (STF-3). About 0.1 times lower in a cylindrical structure without a structural discontinuity (STF-10). (3)On no-crack portions in STF-3, prediction of a method of 'monjyu' is out of a limit of crack initiation, nevertheless one of an advanced proposed method is within the range. Through above results, an advanced proposed method was evaluated to be more accurate in prediction of creep-fatigue damage. We concluded from the above investigation that we calculated more rational and lower damage by proposed method, and it has the possibilities to get extension of a design range.
Tsuji, Hirokazu; *; Nakajima, Hajime
Journal of Nuclear Materials, 208, p.111 - 118, 1994/00
Times Cited Count：0 Percentile：0.01(Materials Science, Multidisciplinary)no abstracts in English
Tsuji, Hirokazu; *; Nakajima, Hajime
JAERI-M 93-173, 19 Pages, 1993/09
no abstracts in English
Tsuji, Hirokazu; *; *; Nakajima, Hajime
Journal of Nuclear Science and Technology, 30(8), p.768 - 776, 1993/08
Times Cited Count：3 Percentile：38.1(Nuclear Science & Technology)no abstracts in English
Tsuji, Hirokazu; *; *; Nakajima, Hajime
JAERI-M 93-105, 22 Pages, 1993/05
no abstracts in English
Tsuji, Hirokazu; *; *; Nakajima, Hajime
Journal of Nuclear Materials, 199, p.43 - 49, 1993/00
Times Cited Count：2 Percentile：27.49(Materials Science, Multidisciplinary)no abstracts in English
Tsuji, Hirokazu
Journal of Nuclear Materials, 203, p.187 - 188, 1993/00
Times Cited Count：0 Percentile：0.68(Materials Science, Multidisciplinary)no abstracts in English
*; Tsuji, Hirokazu; Nakajima, Hajime; *
Proc. of the 4th Int. Symp. on Advanced Nuclear Energy Research (JAERI-CONF 1/JAERI-M 92-207), p.561 - 566, 1992/12
no abstracts in English
Tsuji, Hirokazu; *; *; Nakajima, Hajime
JAERI-M 92-074, 19 Pages, 1992/05
no abstracts in English
Kikuchi, Kenji; Kaji, Yoshiyuki
Transactions of the 11th Int. Conf. on Structural Mechanics in Reactor Technology,Vol. L, p.295 - 300, 1991/08
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 90-053, 56 Pages, 1990/02
A series or multiaxial creep-fatigue tests (uniaxial fatigue, pure torsional fatigue, pure torsional creep-fatigue, proportional fatigue, proportional creep-fatigue) was conducted by Toshiba Corporation as a part of a joint study with PNC. The results of the tests were evaluated by the multi-axial creep-fatigue evaluation method which was developed by the authors in the previous report. The following observation were obtained. (1)Results of multiaxial creep-fatigue tests obtained by Toshiba Corporation coincide well with those obtained by PNC, except those of pure torsional fatigue/creep-fatigue tests. In the case of pure torsional fatigue/creep-fatigue, Toshiba data showed slightly longer lives, (2)Pure torsional creep-fatigue lives reduced as the peak strain hold time increased from 3 minites to 60 minites. A longer hold time would have redeced the creep-fatigue lives even more. (3)In pure torsional creep-fatigue tests with a peak strain hold of 15 minuites, recovery of life was not observed with an additional strain hold time (from 3 minites to 15 minuites) at the other strain peak. (4)It was shown that the multiaxial creep-fatigue evaluation method proposed by the authors could cvaluate the Toshiba data conservatively. Life predictionswere conservative for a factor of 5 and nonconservative for a factor of 2.
*
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
