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Kato, Shoichi; Yoshida, Eiichi; Ishigami, Katsuo*; Yaguchi, Katsumi*
JNC TN9400 2003-108, 92 Pages, 2004/02
JNC-TN9400-2003-108.pdf:36.44MB
A high Cr-Mo steel is a candidate for structural materials of future advanced fast reactors, because of good thermal properties and high creep strength. In this study, creep, creep-fatigue and corrosion tests were carried out to confirm the long-term extrapolation of sodium environmental, effects on the mechanical properties of HCM12A (2001). The exposure to sodium was conducted using a sodium test apparatus constituted by austenitic steels. For the conditions of in-sodium test, the sodium temperature was 550 deg-C and the oxygen concentration in sodium was below 2 ppm. The creep and creep-fatigue strength data in sodium, and in the carburized sodium were within the scattered range of those in air under the same conditions. It is considered that the creep damage in the bulk of the material was dominant. The creep and creep-fatigue life calculated using the usual rule for air showed good agreement with the sodium experimental results. The maximum corrosion rate of HCM12A (2001) was 0.4 micro-m/year at 550 deg-C, and it was almost same as SUS304 and Mod.9Cr-1Mo steels. Corrosion allowance of HCM12A (2001), therefore, can be estimated conservatively by the equation defined in "the elevated temperature structural design guide of prototype fast reactor".
Kato, Shoichi; Sakurai, Tadashi*; Yoshida, Eiichi
JNC TN9400 2003-107, 127 Pages, 2004/02
JNC-TN9400-2003-107.pdf:29.28MB
An oxide dispersion strengthened(ODS) ferritic steel have excellent resistance to swelling and superior creep strength, they are expected to be used as a long-life cladding material in future advallced fast reactor. In this study, sodium environmental effect on the ODS steel developed by JNC were clarified through tensile test after sodium exposure for maximum 10,000hrs and creep-rupture test in sodium at elevated temperature. The exposure to sodium was conducted using a sodium test loop constituted by austenitic steels. For the conditions of sodium exposure test, the sodium temperatures were 923K and 973K, the oxygen concentration in sodium was below 2ppm and sodium flow rate on the surface of specimen was less than 1
10 sup-4 m/s. Further the specimen with the nickel diffused was prepared, which is simulate to nickel diffusing through sodium from the surface of structural stainless steels. The main results obtained were as follows;(1)The results showed excellent sodium-resistance up to a high temperature of about 973K in stagnant sodium conditions, and its considered that the effects of sodium environment on tensile properties were negligible. In case of stagnant sodium condition, creep-rupture strength in sodium was equal to the in argon gas, and no sodium environmental effect was observed. The same is true for the creep-rupture ductility. (2)The tensile properties of nickel diffused test specimens at high temperatures simulating microstructure change were equal to that of the thermal aging process specimens. These tensile tests suggest that sodium environmental effects can be ignored. However, the effect of nickel diffusion on creep strength are not clear at present and experimental investigation are being conducted. (3)The coefficient of nickel diffusion in the ODS steel can be estimated based on the results of nickel concentration measurement. This value is larger than that of the diffusion coefficient for typical alpha-Fe steel at temperature below 973
Kato, Takehiko*;
JNC TN9400 2003-102, 145 Pages, 2004/01
JNC-TN9400-2003-102.pdf:3.74MB
Creep fatigue failure probability calculation program "REAL-P Ver.1.0" (REAL-P here after) is one of the programs of the MSS-REAL system containing REAL-A and REAL-D which perform material strength evaluation, and is a program developed as incorpration of probability theory became necessary in the System Based Code which is being developed. This report describes both the theoretical side and technical specifications including programingi of REAL-P .Particularly, probabilistic fracture mechanics and related techniques such as the Monte Carlo method are explained indetail.
Takasho, Hideki*; Kasahara, Naoto; Kazuteru Garatani/CRC Solution*
JNC TN9400 2003-096, 76 Pages, 2003/12
JNC-TN9400-2003-096.pdf:4.05MB
Commercialized fast reactors, intend to adopt large scale heat exchangers, since they aim at capacity enlargement and reduction of the cooling loops from a demand of the economical efficiency. And, they have planned the adoption of the double-wall heat transfer tubes for reliable design against sodium coolant, which become straight type without tube welding. As the result, steam generators change to large double straight pipe types and the large-scale dished tubesheets are required from a balance with the pressure proof design. The establishment of method of structural analysis for the complicated and three-dimensional shape is required in order to realize the large-scale dished tubesheets. Conventional analysis models for tubesheets are equivalent solid plates with stress multipliers, which are difficult to be applied to dished tubesheets since their un-homogeneity. A large-scale three-dimensional analysis model is desirable to consider precious configurations around holes.. The iterative solver for efficiently calculating, when the large-scale analysis is carried out, was developed, and it was mounted to FINAS code. A dished tubesheet model for commercialized fast reactors was made in three-dimensional element which exceeded 1 million degrees of freedom. FINAS code with the iterative solver analyzed thermal transient stress under the manual trip condition. 20 step calculation was carried out within 72 hours on PC. As the result, it was confirmed that applicability of three dimensional analysis methods to dished tubesheets.
Yoshida, Eiichi; Hirakawa, Yasushi; Kuroko, Koichi*; Yoshida, Eiichi
JNC TN9400 2003-049, 119 Pages, 2003/06
JNC-TN9400-2003-049.pdf:6.54MB
A lead-bismuth eutectic (PbBi alloy) is one of candidates for an intermediate heat transport medium used in a steam generator of future sodium cooled fast reactor. This experimental study has been carried out to investigate the reaction phenomena and the basic physical properties of reaction products of the PbBi alloy and sodium (Na), when the PbBi alloy leaks to the sodium circuit system.