Helicopter Operation at Fukushima Nuclear Disaster

At 14:46 JST on March 11, 2011, a massive earthquake hit the northeastern coast of Japan. The magnitude of the earthquake was 9.0 (Mw). It was the most powerful earthquake ever recorded in Japanese history. The earthquake triggered a deadly tsunami and swept away thousands of houses and lives. At the same time, the Fukushima Dai-ichi (No1) nuclear power plant was struck by the tsunami and the reactor took serious damage. This caused reactors to have a core meltdown and explode. There had been a radiation leak in the nuclear power plant. On March 15, the Japanese government set the restricted area within 30 km from the Fukushima nuclear power plant due to the radiation leakage. On March 17, two Japan Self Defense Force (JSDF) CH-47J helicopters dropped water to cool the failing reactor. The mission was successful, and the radiation around the reactor was gradually decreased, allowing for further operations. On April 14, one month after the disaster, the Japanese government requested the dispatchment of the Japan Coast Guard (JCG) for a search and rescue mission within the restricted area. This was the first search and rescue mission held at sea within a radioactive-contaminated environment in Japan, for which nine patrol boats, two airplanes, and three helicopters were sent for the mission. This paper describes the general outline about the cooling, thermo-monitoring, and the search and rescue missions as well as the equipment used, maximum permissible dose of radiation, and the mission environment. Then it compares this data with the helicopter operations during the Chernobyl accident. The purpose of this paper is to expand readers' knowledge about helicopter operations during nuclear disasters with the hopes for it to be a useful material for future missions. The story of this paper is based on the author's experience as a dispatched Japanese Coast Guard helicopter pilot.