Behavior of plasma facing surface in the large helical device / by Hino, T., Sagara, A., Nobuta, Y., Inoue, N., Hirohata, Y., Yamauchi, Y., Masuzaki, S., Noda, N., Suzuki, H., Komori A., Ohyabu, N., Motojima, O., LHD Experimental Group, IAEA Fusion Energy Conference (19th : 2002 : France)