警戒区域による船舶への影響

抄録

After the accident at the Tokyo Electric Power Company's Fukushima No.1 nuclear plant on March 11, 2011, 20 km within the plant became a caution zone. Since April 22, 2011, ship navigation within the marine area of the zone also became an off-limits area and the navigation area of domestic vessels that navigate the coasting area became nearly half. In this paper, ship wakes offshore of Fukushima were confirmed and the dangers of collision were evaluated quantitatively before and after the designation of the caution zone. After the designation of the caution zone, ship density (total ship navigation time) navigating offshore Fukushima had become 1.2 times larger and the mean ship velocity of ships that used to navigate the caution zone had risen. The danger of collision had risen after the designation. Three measures to lower the danger of collision were considered in this paper: lifting caution zone of the marine area, expansion of the coasting area and divided lane offshore Fukushima.