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Yoshida, Eiichi; Yaguchi, Katsumi*; Aoto, Kazumi
JNC TN9400 2004-061, 42 Pages, 2004/05
JNC-TN9400-2004-061.pdf:3.78MB
In sodium cooled fast reactors, when a very small-scale sodium leakage occurs to an air atmosphere through a fine crack of component or piping in the sodium systems, sodium may produce corrosive compounds by the chemical reactions with the air atmosphere, and corrosion damage of component materials may be induced. Therefore, evaluation of the corrosion behavior and the amount of damages of the component materials by the corrosive compound is important from the viewpoint of a design of a plant and maintenance management. The corrosion tests were conducted with the parameters NaOH concentration [55-100mass.% NaOH] and NaOH solution temperature [348-1027K] for the SUS304 stainless steel which is a typical structure material. The corrosion rate and corrosion crack susceptibility were examined. As the results, the corrosion rate of SUS304 was dependent on the temperature of NaOH solution, though the influence of NaOH concentration in solution was small. The different temperature dependency was shown in 55-85% NaOH solution and 100% NaOH. The activation energy was about 30kcal/mol in 55-85% NaOH solution and was about 9kcal/mol in 100% NaOH, respectively. The corrosion rate of this experiment was roughly in agreement with the reference values in NaOH solution obtained by the past experiments. The morphology of corrosion was general corrosion under all conditions. In the SCC experiment using the U-bend test specimen, TGSCC was observed under a part of condition. However, the observed region in this study was within the limits of the SCC boundary region of SUS304 in sodium-hydroxide solution.
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".
; Yoshida, Eiichi; Sakurai, Tadashi*; Yaguchi, Katsumi*
JNC TN9450 2003-001, 192 Pages, 2003/03
JNC-TN9450-2003-001.pdf:11.59MB
In order to evaluation of high temperature creep strength, creep tests under internal pressure on the fuel cladding tube for fast breeder reactor (FBR) has been preformed in New Technology Development Group. In this report, the result of the creep and creep-rupture properties on the advance austenitic stainless and high-Ni steels obtained up to this time was collected. Valuable test data totals 149 points including sodium environment test data. These data will be reflected in development and design for fuel cladding material. Contents of the data sheet are as follows ; (1)Material and number of data: 15Cr-20Ni steel (2 heats) 72 points, PNC1520 steel (1 heats) 6 points, 14Cr-25Ni steel (8 heats) 56 points, High-Ni steel (1 heat) 15 points (2)Test environment : In-air, In-argon gas and In-sodium (3)Test temperature : 600
C to 750C(873K to 1023K)