Dr. Tsubokura's Radiation Lecture Vol.122

Author: Masaharu Tsubokura M.D., PhD.

Editors: Akihiko Ozaki M.D., PhD., Yuki Senoo

243. Reformed evacuation plan

　　　　The 2011 Fukushima Daiichi nuclear accident provided a vivid visual of the importance of an emergency response plan for a nuclear accident. Reflecting on the events that occurred during and after the nuclear accident, various countermeasures and preparations have been modified.

　　　　One of the significant changes made to the nuclear emergency response after the Fukushima nuclear accident was the evacuation zone’s extent. Before the nuclear accident, disaster prevention measures were focused on areas within an 8?10 km radius from a nuclear power plant. However, as you know, this accident required the evacuation of a larger area. Therefore, taking international standards into consideration as well, disaster prevention and evacuation plans are now formulated for areas within approximately 30 km of power plants.

　　　　Additionally, strict standards were specially designated for areas within a 5 km radius from power plants, called precautionary action zones (PAZs). During a nuclear emergency, such as a nuclear power plant accident or reactor coolant system failure, precautionary evacuations will be implemented in PAZs before the emission of radioactive substances.

244. Residents in areas close to nuclear power plants require precautionary evacuation

　　　　As mentioned in the previous article, the 2011 Fukushima Daiichi nuclear provided a vivid visualization of the importance of an emergency response plan for a nuclear accident. Reflecting on the events that occurred during and after the nuclear accident, various countermeasures and preparations have been modified.

　　　　One of the major changes made after the nuclear accident was the extension of the area for evacuation plans. Under the previous nuclear emergency response system, disaster prevention plans and evacuation plans were designated for areas within a radius of approximately 30 km from the power plant. However, new orders, including the process of emergency preparation, radiation protection, and the schedule for evacuation orders during a nuclear accident, are different depending on a location’s distance from a power plant. For example, a mandatory evacuation order will be issued immediately for areas closest to a nuclear emergency, while residents in areas further away will wait until the air radiation dose rate increases.

　　　　The area within a 5 km radius of a plant is called a PAZ (precautionary action zone), and the area within 5 to 30 km of a plant is called the UPZ (urgent protective action planning zone). When a nuclear emergency occurs, precautionary evacuation will be implemented in the PAZ before the release of radioactive substances from the power plant. On the other hand, in a UPZ, an evacuation order will be issued to a specific location when high radiation doses are actually measured.

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The Japanese version of the manuscript was originally published in Fukushima Minyu, a local newspaper in Fukushima prefecture, Japan, 8th and 15th of September 2019 was reproduced for MRIC Global under the author's permission.