2018-2019 MIAE Graduate Seminar Series
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About The Event
MIAE 2018-2019 Graduate Seminar Series
“Pipeline Break Mechanism in Mihama Power Plant Caused by Flow Accelerated Corrosion”
By Prof. Nobuyuki Fujisawa, Niigata University, Japan
Pipeline break mechanism in Mihama Nuclear Power Plant (NPP) is known as one of the wall thinning accidents in Japan in 2004, which is caused by flow accelerated corrosion (FAC). FAC is a corrosion phenomenon of carbon steel pipeline caused by flow turbulence. The Mihama pipeline consisted of an elbow and orifice, while the flow was highly swirling in the upstream. The water tunnel experiment by the authors showed that the mass transfer coefficient was locally increased behind the orifice to a value several times larger than that of the straight pipe. This phenomenon was found to be caused by the high intensity swirling flow through the elbow, which generated a spiral motion downstream of the elbow and sustained a longer distance than expected from an elbow flow without swirl. This type of non-axisymmetrical flow triggered strongly biased flow at the orifice, and resulted in non-axisymmetric pipe-wall thinning downstream of the orifice leading to pipe-break accident in the NPP.
Dr. Fujisawa is a Professor in Department of Mechanical Engineering at the Niigata University. He received a PhD degree in Mechanical Engineering from Tohoku University. He worked as Research Associate and Associate Professor in Gunma University before moving to Niigata University as a Professor. He has studied various flow visualization techniques, such as the flow visualization (smoke-wire, oil film, tuft, particle), scalar measurement (laser-induced fluorescence, temperature sensitive liquid crystal, shear-sensitive liquid crystals, flame reaction) and velocity vector measurement (planar, stereo, scanning particle image velocimetry). These experimental flow visualization techniques were applied to study various flow fields, such as wind and water turbines, jets, plumes, combusting flames. Recently, he has been working on Flow Accelerated Corrosion (FAC) and Liquid Droplet Impingement (LDI) erosion, which is closely related to the pipe-thinning accidents of Mihama Nuclear Power Plant (NPP) in 2004. Dr. Fujisawa was the Director of Flow Visualization Society of Japan, Managing Editor of J. Visualization, and President of Visualization Research Center of Niigata University more than a decade. Now, he is working as a Vice president of Flow Energy Society of Japan and as an Editor-in-Chief of J. Flow Control, Measurement and Visualization. Now, he is a Technical Committee Member for Niigata Prefecture for preventing NPP accident in Japan.