Long-term experiences in keeping balance between safety and usability in research activities in KEK Tadashi Murakami, Fukuko Yuasa, Ryouichi Baba, Teiji Nakamura, Kiyoharu Hashimoto, Soh Y. Suzuki, Mitsuo Nishiguchi and Toshiaki Kaneko EPJ Web Conf., 214 (2019) 08001 Published online: 17 September 2019 DOI: 10.1051/epjconf/201921408001