TOKYO -- The cooling system of a pool that stores spent fuel at the Fukushima Daini nuclear plant's No. 3 reactor automatically shut down at around 6:10 a.m. Tuesday, after a magnitude-7.4 earthquake struck off the coast of Fukushima Prefecture, Tokyo Electric Power Co. Holdings said the same day.
The cooling system was restarted at 7:47 a.m. Tepco said it had not detected any radiation leaks or unusual radioactivity in the area. The plant has been shut down since the earthquake and tsunami in March 2011, but spent nuclear fuel remains in storage in the cooling pool.
"We are very sorry for worrying you," said Naohiro Masuda, the Tepco executive overseeing the decommissioning of the Fukushima Daiichi plant at a news conference at the company's Tokyo headquarters. According to the utility, no new problems have been observed at Fukushima Daiichi.
Toyota Motor East Japan, a subsidiary of Toyota Motor that has three plants in the Tohoku region of northern Japan, is checking for damage from the quake.
East Japan Railway temporarily halted the Tohoku, Joetsu and Hokuriku Shinkansen bullet trains. All lines have resumed operation. Airlines also have restarted flights at Sendai Airport.