Water used to cool radioactive waste at the stricken nuclear complex in Japan did not dry up, as earlier feared, U.S. regulators said.
U.S. officials had warned all the water was gone from one of the spent fuel pools at Japan’s troubled nuclear plant, raising the possibility of widespread nuclear fallout. Loss of cooling water in the reactor core could have exposed highly radioactive spent fuel rods, increasing the threat of a complete fuel meltdown and a catastrophic release of radiation.
Japanese officials denied the pool was dry and reported that the plant’s condition was stable.
U.S. officials said after viewing newly obtained video the spent fuel pool at Unit 4 at the Fukushima Dai-ichi complex probably did not go dry, as Nuclear Regulatory Commission Chairman Gregory Jaczko insisted in March.
Bill Borchardt, the NRC’s executive director for operations, said U.S. officials welcomed the video evidence as “good news” and one indication the meltdown at the Fukushima plant’s Unit 4 reactor “may not have been as serious as was believed.”
A spokesman for the NRC said the belief the spent fuel pool may have gone dry played a role in Jaczko’s decision to recommend U.S. citizens stay at least 50 miles away from the crippled Japanese plant. The Japanese authorities had ordered evacuations of people within about 12 miles of the plant.
NRC spokesman Scott Burnell said Jaczko and other U.S. officials made the recommendation based on the best information available at the time.
“The NRC felt and continues to feel that the 50-mile recommendation was appropriate,” he said.
Meanwhile, Charles Miller, a senior NRC executive who is leading a 90-day safety review of U.S. nuclear plants, told commissioners current safety rules do not adequately weigh the risk of a single event that could knock out power from the grid and from emergency generators, as the quake and tsunami did in Japan. Safety experts until now have focused on the risk of losing electricity from the grid or from emergency sources, but not both.