Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Isozaki, Kazunori;
PNC TN9410 97-062, 169 Pages, 1997/05
Sodium leak accident of MONJU was caused high cycles fatigue damage of thermometer well by flow-induced vibration. It was due to the sy㎜etric vortex shedding which was occurred rear flow of thermometer well. So, Thermometer wells installed in primary and secondary heat transport systems of JOYO were evaluated of flow-induced vibration. Evaluation of flow-induced vibration of thermometer well was done checking of flow-induced vibration base on authorized design report for JOYO, evaluation of summary flow-induced vibration by natural frequency of thermometer well in sodium as cantilever models, and evaluation based on small velocity rule of ASME Code Section III Appendix N-1300. By this result, thermometer wells (12B piping of secondary cooling system) were not sattisfied requirement to avoid flow-induced vibration by small velocity rule. Therfore, Detailed vibration characteristic analysis, water flow-induced vibration test, dumping test and evaluation of structural integrity were carried out. These results, vibration amplitude of well on the tip was 0.13mm (vibration non-dimensional amplitude of 0.015) and peak stress of 2.9kg/mm
is occurred. Thermometer wells (12B piping of secondary cooling system) which occurred peak stress by flow vibration was confirmed enough to satisfy 5.3kg/mm2 of design fatigue limit.
Furukawa, Tomohiro; ; Yoshida, Hidekazu;
PNC TN9410 93-042, 56 Pages, 1993/02
Mod.9Cr-1Mo steel is a candidate material of once-through type steam generators for the Fast Breeder Reactors, and it is required to clarify low-cycle fatigue properties in air at high temperature on this material for structural design. So the tests were carried out for three heats (12mmt plate, 25mmt plate and 250mmt forged) on conditions that temperature is 450
650
C and strain range is 0.41.2%. Results obtained are su㎜araized as follows. (1)For cyclic stress-strain behavior of Mod.9Cr-1Mo steel cyclic hardening was. observed in the early stage, and after that changed to softening to failure. The behavior was similar to normalized and tempered 2.25Cr-1Mo steel. (2)Low-cycle fatigue strength of Mod.9Cr-1Mo steel in air was remarkably higher than that of 2.25Cr-1Mo steel, and almost same as much as that of SUS304 steel. Moreover, fatigue life of Mod.9Cr-1Mo steel was longer than that of 9Cr-2Mo or Low C-9Cr-1Mo-Nb-V steel under low strain conditions. (3)In the case of Mod.9Cr-1Mo forged steel, the influence of the sampling position and direction of specimens was not effective. These results were reflected to prepare of tentative material strength standard in 1992.
; Kawasaki, Hirotsugu; Aoto, Kazumi; Yoshida, Eiichi; ;
PNC TN9410 92-089, 61 Pages, 1992/03
The allowable strain range 
of Mod.9Cr-1Mo (NT) steel has been substituted by that for 2-1/4Cr-1Mo (NT) steel in last version of material strength standard in 1989. Because of the a small amount of fatigue test data on Mod.9Cr-1Mo (NT) steel, it is difficult to determine the best fit curve and allowable strain range of Mod.9Cr-1Mo (NT) steel can be evaluated conservatively by the values of 2-1/4Cr-1Mo (NT) steel. Low-cycle fatigue tests by various strain rates and the high-cycle fatigue tests were carried out to determine the new best fit fatigue life equation of this material. In this report, the fatigue life equation of Mod.9Cr-1Mo (NT) steel is and the interim new version of allowable strain range is proposed. The obtained results are as follows, (1)In the best fit fatigue life equation of Mod.9Cr-1Mo (NT) steel the effects by both of the temperature and low strain rate should be considerd. As the analytical methods to consider these dependency in the fatigue life equation, the correlation to the fatigue properties of 2-1/4Cr-1Mo (NT) steel is examined. Some data fitting methods based on the fatigue equation for 2-1/4Cr-1Mo (NT) steel are tried and compared. One of these methods could give a good prediction for the fatigue properties of the Mod.9Cr-1Mo (NT) steel up to high cycle range. (2)The interim standard of allowable strain ranges A , B and C (for strain rate of 10
, 10
and 10
s 
) for Mod.9Cr-1Mo (NT) steel could be proposed by the new best fit fatigue life equation. (3)The proposed allowable strain range at 375C was compared to the present design fatiuge curve of low alloy steel of MITI Notice No501, and it was clarified that the fatigue strength of Mod.9Cr-1Mo steel was too higher. The design fatigue curve for Mod.9Cr-1Mo (NT) steel will be revised to higher design value (twice for starin range at l0
cycles) than the present design fatigue curve of low alloy steel.
; ;
PNC TN9410 92-148, 65 Pages, 1992/02
Mod.9Cr-1Mo steel is the material whose future utilization is expected as an advanced material of the steam generater of the Fast Breeder Reactors. A procedure for evaluation of weldment is being developed as one of the main concerns for the utilization of this material. The purpose of this report is to propose a fatigue strength evaluation method of Mod.9Cr-1Mo weldment which incorporates the effect of the heat affected zone which forms the softest portion of the weldment on the strength of the weldment. The mechanisms of strain concentration in the weldments of Mod.9Cr-1Mo steel was analysed and fatigue fracture was evaluated in terms of strain concentration. It was shown that the maximum strain concentration occured in the heat affeted zone at the begining of cyclic strain loading but that as a result of cyclic softning which was evident with the base metal but negligible with the heat affected zone the maximun strain concentration moved on to the base metal after half-life under the assumption that the hardness of the base metal and the heat affected zone coincide with each other at about half-life. Furthermore, based on this result, fatigue damage was evaluated. It was shown that the accumulated fatigue damage was not the maximum in the heat affected zone and that fatigue failure did not occur in the heat affected zone as far as the present analyses concerns. It was also made clear that fatigue failure occur in the base metal due to the strain concentration at strain ranges higher than elastic reagion and that it occur in the weld metal due to its inferior fatigue strength compared with the base metal. As a result, it was clarified that the fatigue strength of Mod.9Cr-1Mo weldment is reasonably evaluated by FE-analysis, which observation is able to be applied to the analysis of structures with weldments to be evaluated.
*
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.
; *;
JAERI-M 6213, 43 Pages, 1975/08
no abstracts in English
