Evacuation after nuclear accident: 12 hours to 6 days

January 14, 2013

12 hours needed for people within 30-km radius of nuclear plants to evacuate: study

http://mainichi.jp/english/english/newsselect/news/20140114p2a00m0na010000c.html

At least 12 hours would be needed for everyone living within a radius of 30 kilometers from nuclear power plants in Japan to evacuate in the event of a nuclear accident, according to research results conducted by a private group.

In cases where the use of evacuation routes is limited to national highways due to complex disasters such as earthquakes, people within a radius of 30 kilometers from the Tokai No. 2 Power Station in Ibaraki Prefecture would need five days and a half to complete their evacuation. Those people living near the Hamaoka Nuclear Power Station in Shizuoka Prefecture would likely need about six days to move out of the 30-kilometer zone, the research findings show.

The research, conducted by "Kankyo Keizai Kenkyujo" (research institute on environmental economics), is apparently the first analysis covering all of the nuclear power plants in Japan. The research results highlight the fact that it is almost impossible for all of the residents near a nuclear power station to evacuate fast enough to avoid radiation exposure in the event of an accident in which radioactive substances are released into the atmosphere.

The research results are due to be announced at a seminar to be hosted on Jan. 25 by the Association for the Research of Transportation Problems and Human Rights.

The research was conducted on municipalities that lie within a radius of 30 kilometers from nuclear power plants and are required to prepare emergency evacuation plans under the government's guidelines for responses to nuclear disasters. The research was also based on the assumption that 30 percent of registered buses and 50 percent of registered privately-owned cars in each of those municipalities would be used for evacuation.

The study was also based on the assumption that all of the residents in a given area would start moving simultaneously to evacuate, and traffic engineering techniques, which take into account such factors as traffic jams, were employed for the analysis. The research dealt with two different scenarios for calculations: cases in which only national highways can be used because of disaster-inflicted damage or emergency vehicles taking other routes; and cases in which all of the routes including national highways, expressways and other major local roads can be used.

As it turned out, in cases where only national highways are used for evacuation, at least 15 hours are estimated to be needed for all of the residents within the 30-kilometer radius of the Tomari Nuclear Power Plant in Hokkaido to complete their evacuation, while nearly six days are estimated to be needed for residents near the Hamaoka Nuclear Power Station. Even in cases where expressways and other roads can be used, eight hours are estimated to be needed for residents near the Oi Nuclear Power Plant in Fukui Prefecture to complete their evacuation -- the shortest among nuclear plants across the country -- while 63 hours are required for residents near the Hamaoka Nuclear Power Station -- the longest of all when using expressways.

In the case of the Hamaoka Nuclear Power Station, although about 740,000 people are living within a 30-kilometer radius, there are limited numbers of roads available. The situation is such that there will likely be heavy traffic jams involving private cars and even bus transportation will likely make little headway, forcing residents to take a long time to evacuate. Similar research results were found for the Tokai No. 2 Power Station which involves the prefectural capital, as well as for the Shimane Nuclear Power Plant in Shimane Prefecture.

Although the estimates were based on simplified assumptions, they show similar tendencies seen in detailed simulations released by some of the municipalities. The Hokkaido Prefectural Government estimates that it will take 12 hours and a half for residents within a 30-kilometger radius of the Tomari Nuclear Power Plant to complete their evacuation. The Ibaraki Prefectural Government estimates that residents within a 30-kilometer radius of the Tokai No. 2 Nuclear Power Station would need 17 hours to complete their evacuation, and it would take 39 hours and a half for them to evacuate if the Joban Expressway is closed. Kyoto Prefecture residents living within a 30-kilometer radius of the Takahama Nuclear Power Plant and the Oi Nuclear Power Plant, both in Fukui Prefecture, are estimated to take up to 29 hours and 20 minutes, respectively, according to an estimate made by the Kyoto Prefectural Government.

Naomi Kamioka, who heads the research institute and also serves as vice chairman of the Association for the Research of Transportation Problems and Human Rights, said, "Although activities aimed at restarting nuclear reactors are shifting into high gear, road conditions around the nuclear power plants have not been drastically improved even after the Fukushima nuclear accident."