Evacuation drills to transport residents to safety by sea and air due to a nuclear plant accident have been canceled more than 20 times in the past five years due to inclement weather, showing the danger in an emergency.  

According to a survey conducted by The Asahi Shimbun, the figure accounts for more than 20 percent of about 100 planned drills by municipal and prefectural governments. 

In the survey, officials of 21 prefectural governments within a 30-kilometer radius from 16 nuclear plants across the country were contacted.

The results offer a reminder that residents could be left stranded when land routes become impassable due to earthquakes and other occurrences, while sea and air routes, which offer a final alternative, are also cut off depending on weather conditions.

EVACUATIONS FACE DIFFICULTIES

Under guidelines for emergency preparedness and response established by the central government, residents within 5 km of a nuclear plant must immediately evacuate in the event of a nuclear plant accident.

Residents living in a 5-to-30-km radius from the plant will be advised to take shelter indoors and evacuate beyond a 30-km radius when radiation levels reach a designated threshold.

Under local governments' evacuation plans, residents, except for those living on remote islands, are generally supposed to flee in their cars, buses or other means of land transportation.

But if they are stranded due to damaged roads or other reasons, sea and air routes will also be taken into consideration.

And when it is difficult to evacuate via any of the means, residents will be instructed to stay indoors.

Based on the basic law concerning countermeasures against natural disasters, prefectural and municipal governments within a 30-km radius of nuclear power plants conduct evacuation drills simulating an accident at a nuclear facility.

The drills are jointly hosted by the central government, utilities, the Self-Defense Forces, police and other organizations to train participants on how to guide evacuees to safety, maintain communication with authorities in emergencies, convey information to residents and restrict traffic.

Municipalities and prefectures hosting or surrounding nuclear power plants conduct such drills typically once a year.

Based on their evacuation plan, local governments conduct drills to evacuate residents by land, sea and air as necessary.

However, officials of 21 prefectural governments told The Asahi Shimbun that 11 of 47 drills using sea routes planned between fiscal 2020 and fiscal 2024 were canceled due to high waves and strong winds.

Meanwhile, 11 of 51 drills using air routes were called off during the same period due to poor visibility and other conditions.

Such cancellations were made in 12 prefectures.

NO ESCAPE ROUTES

Oct. 29 marked one year since Tohoku Electric Power Co. restarted the No. 2 reactor at its Onagawa nuclear power plant located in Onagawa town and Ishinomaki city in Miyagi Prefecture.

The restart marked the first of a nuclear plant that suffered damage in the 2011 Great East Japan Earthquake and tsunami.

In February, the first nuclear disaster drill after the restart was jointly conducted by the Miyagi prefectural government and municipalities within a 30-km radius of the Onagawa plant.

Shin Mitsumori, 67, head of a neighborhood association in the Ayukawahama district of Ishinomaki, located near the tip of the Oshika Peninsula, was planning to join the drill on a ship from a nearby port.

But the evacuation drill using sea routes was canceled the day before it was held.

According to prefectural officials, moderately strong winds were forecast for that day. The sea-route evacuation exercise was carried out as planned between 2021 and 2023.

"If we can't join the drill, there is no way we can evacuate," Mitsumori said.

The port was hit by an 8.6-meter-high tsunami generated by the magnitude-9.0 earthquake 14 and a half years ago.

The first floor of his house was flooded to the ceiling.

The roads were covered with debris, making it impassable for cars.

"The port was not operational because of the tsunami, and there was no way for ships to leave," he added. "Should something similar happen again, we can't flee."

In fiscal 2021, the Niigata prefectural government, which hosts Tokyo Electric Power Co. Holdings Inc.'s Kashiwazaki-Kariwa nuclear power plant, called off an evacuation drill by sea due to high waves and also a nighttime drill using a helicopter because of poor visibility.

During an evacuation drill jointly conducted by the state and prefectural governments in fiscal 2023, part of an exercise using a helicopter was canceled due to bad weather. Instead, they organized an evacuation drill via land routes.

"We prioritize residents' safety when we conduct drills, but things will be different if an accident threatening human lives occurs," an official said, adding that it is possible to mobilize helicopters and ships in the event of an emergency.

However, a senior member of the Self-Defense Forces in charge of transporting evacuees by sea and air said, "If we are to transport disaster victims, then we focus on safety even more. We go out into the field if it is urgent, but there will be increased danger of secondary damage."

When all land, sea and air evacuation routes become unusable, evacuees' only option is to stay indoors.

Taking such circumstances into consideration, several municipalities conducted a drill for participants to take shelter indoors after evacuation exercises using sea and air routes were suspended.

PRIORITIZE LAND ROUTES

Shinya Yasumoto, a project assistant professor specializing in disaster information at the University of Tokyo, said helicopters and other aircraft can carry only a limited number of people, while it is also unreasonable to dispatch ships when tsunami alerts are issued.

"Realistically, efforts must be made to flesh out land routes, which are the main means of evacuation, except in peninsula areas where it is difficult to evacuate via land routes," he said.

"For that, it is necessary (for local governments) to work with utilities, infrastructure companies, schools, police, the Self-Defense Forces, medical institutions, welfare facilities and other organizations to draw up training programs on a routine basis and share possible scenarios."

(This article was written by Megumi Kishi, Hiroyuki Yaginuma and Shiori Tabuchi.)