A 7.4-magnitude earthquake struck off the coast of northeastern Japan’s Fukushima prefecture late Wednesday causing damage and service disruptions to two nuclear power plants in Fukushima and killing three people across Japan, the Asahi Shimbun newspaper reported Thursday.
The Fukushima Daiichi (No. 1) nuclear power plant was the site of a nuclear disaster on March 11, 2011, after a 9.0-magnitude earthquake off the prefecture’s coast together with a resultant tsunami “disabled the power supply and cooling of three Fukushima Daiichi reactors, causing a nuclear accident,” according to the World Nuclear Association.
Though not nearly as destructive as the March 2011 earthquake, Wednesday’s tremor did affect the normal operations of the Fukushima Daiichi (No. 1) and Fukushima Daini (No. 2) nuclear plants.
The Tokyo Electric Power Co. (TEPCO), which runs the two nuclear plants, said “coolant pumps for pools storing spent nuclear fuel were shut down for hours at [the] two nuclear power plants” after the March 16 earthquake struck around 11:30 pm.
Japan’s Asahi Shimbun newspaper relayed an explanation of the incident by TEPCO on March 16, writing:
At 11:34 p.m., right after the first quake struck off the coast of Fukushima Prefecture, the coolant pump automatically halted for the spent fuel pool in the No. 5 reactor building at the stricken Fukushima No. 1 nuclear power plant.
The cooling facilities in the No. 2 reactor building also stopped running at around midnight because the water level in the tank connected to the spent fuel pool had dropped. …
TEPCO also confirmed that water inside the spent fuel pools spilled out at the No. 5 and No. 6 reactor buildings but remained within the structures.
At the Fukushima Daini (No. 2) nuclear power plant, “coolant pumps for spent fuel pools were shut down at the No. 1 and No. 3 reactor buildings,” according to TEPCO.
The Fukushima Daini (No. 2) nuclear power plant additionally suffered the following effects from the March 16 earthquake, according to the Asahi Shimbun:
The quake … warped a panel opening in a door at the No. 1 reactor building that releases pressure in emergencies to prevent hydrogen explosions. … [and] slightly shifted the position of a tank storing contaminated water in the compound of the plant.
Wednesday’s natural disaster affected 11 Japanese prefectures outside of Fukushima, resulting in over 180 injuries and at least three deaths, Tokyo’s Kyodo News Agency reported on March 17. The earthquake derailed a high-speed train full of passengers as it traveled between the prefectures of Fukushima and Miyagi on Wednesday night.
“A Tohoku Shinkansen bullet train derailed between Fukushima Station and Shiroishizao Station [in Miyagi], but all 78 passengers and crew members aboard were unharmed,” the East Japan Railway Co., which operates the locomotive, said.
“The quake also caused power outages in northeastern and eastern Japan, affecting a total of more than 2.2 million households, including some 700,000 in Tokyo, according to TEPCO Power Grid Inc. and Tohoku Electric Power Network Co.,” Kyodo News reported on Thursday, adding “Power was later restored to most.”