A nuclear disaster drill for simultaneous accidents at the Oi and Takahama nuclear power plants in Fukui Prefecture ended Sunday after mobilizing 21,000 people.

It was the first disaster response drill designed for serious simultaneous accidents at multiple plants since the Fukushima nuclear crisis in March 2011.

The drill involved about 21,000 people including residents and officials from the Cabinet Office, the Nuclear Regulation Authority and municipal governments.

Sunday’s exercise focused on evacuating residents from Fukui and surrounding prefectures. It also involved personnel aboard the Maritime Self-Defense Force minesweeper tender Bungo, which was deployed to provide first aid to “injured” participants who were ferried there by helicopter.

In the town of Takahama, 20 residents were flown to Osaka on a Ground Self-Defense Force CH-47J chopper and bused to Sanda in Hyogo on the assumption that a evacuation route was cut off by a landslide.

Preparations involving the Oi and Takahama plants, both managed by Kansai Electric Power Co., are deemed necessary as they are just 13.5 km away from each other.

The exercise assumed radioactive substances were released after an earthquake in northern Kyoto knocked out the cooling systems of the two plants’ reactors.

As part of the drill, task forces created at the two plants’ off-site emergency response centers were integrated into Oi’s task force.

Katsunori Yamamoto, 64, who runs a nursing home 5 km from the Takahama plant, played one of his residents. He was evacuated to Tsuruga by a wheelchair-accessible van driven by a Kansai Electric worker.

“I want to assess risks to our nursing home residents,” he said.