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The Working Team for Examination of the Sample from Core Shrouds and Primary Loop Recirculation Pipi
JAERI-Tech 2004-011, 64 Pages, 2004/02
At the Kashiwazaki-Kariwa Nuclear Power Station Unit-1 of the TEPCO, cracks were confirmed at the weld joint (H4) in the middle of core shroud, by the visual inspection test for the weld joint of core shroud during the 13th periodic examination by a direction of the Nuclear and Industrial Agency. TEPCO has conducted a material examination with NFD on the specimen including cracks sampled from the core shroud. The present research has been performed with the objective to independently investigate and evaluate the materials by jointly attending the examination with NFD from the planning stage, receiving the final data given by the examination and providing JAERI's own evaluation report as a third-party organization for assuring the transparency. As a result, the consideration of residual stress induced with welding process and dissolved oxygen concentration in core cooling water, it was concluded that the cracks were initiated by SCC and propagated three-dimensionally through grains, and some cracks reached weld metal.
Kikuchi, Kenji; Saito, Shigeru; Kurata, Yuji; Futakawa, Masatoshi; Sasa, Toshinobu; Oigawa, Hiroyuki; Umeno, Makoto*; Mori, Keijiro*; Takano, Hideki; Wakai, Eiichi
Proceedings of 11th International Conference on Nuclear Engineering (ICONE-11) (CD-ROM), 7 Pages, 2003/04
In order to construct ADS Target Test facility in J-PARC project the research and development on Pb-Bi technology have been carried, which cover target design with computer simulation, flowing loop test, stagnant corrosion test, oxygen sensor and cleaning techniques. Obtained results are as follows: Corrosion rate of SUS316 under flowing Pb-Bi at 1m/s at 450C is 0.1 mm / 3000 hrs. Fe and Cr were melted into lead bismuth from SS316 in the high temperature part and deposited in the low-temperature part according to the difference of solubility. The corrosion thickness decreases with increasing Cr content in the stagnant corrosion test at saturated oxygen concentration. Reliable oxygen sensors are to be developed by using suitable reference electrodes. As a result of cleaning tests, blushing process was needed to remove Pb-Bi effectively after immersion in the silicon oil. The mixed acid easily dissolved Pb-Bi and removed almost perfectly. But specimens themselves were affected by coloring.
Nishitani, Takeo; Ebisawa, Katsuyuki*; Walker, C.*; Kasai, Satoshi
JAERI-Tech 2002-033, 40 Pages, 2002/03
no abstracts in English