Tepco: Fukushima Fuel Rods Are Fully Exposed By Michio Nakayama and Tsuyoshi Inajima - May 12, 2011 Tokyo Electric Power Co. said fuel rods are fully exposed in the No. 1 reactor at its stricken Fukushima Dai-Ichi nuclear plant, setting back the utility’s plan to resolve the crisis. The water level is 1 meter (3.3 feet) below the base of the fuel assembly, Junichi Matsumoto, a general manager at the utility known as Tepco, told reporters at a briefing in Tokyo. Melted fuel has dropped to the bottom of the pressure vessel and is still being cooled, Matsumoto said. The company doesn’t know how long the rods have been exposed, he said. Tepco is trying to contain the worst nuclear disaster since Chernobyl after a quake and tsunami two months ago knocked out power and cooling systems at the Fukushima station. The utility planned to flood the No. 1 containment chamber, which surrounds the reactor vessel, in a procedure known as water entombment to prevent fuel from overheating. “I’ve been saying from the beginning the water tomb plan won’t work,” said Tadashi Narabayashi, a professor of nuclear engineering at Hokkaido University. “Tepco must work on a water circulation cooling system as soon as possible. They’ve been going round and round in circles and now realize this is what they need to do.” It’s unlikely the situation has worsened with the discovery the rods are exposed because they’ve probably been out of the water since shortly after the crisis started, Narabayashi said.
Spewing Radiation Tepco shares fell 8.8 percent to 479 yen in Tokyo today. The stock has declined 77 percent since the quake and tsunami, which left more than 24,000 people dead. The six-reactor complex, Japan’s third-largest by capacity, has been spewing radiation since March 11 and the severity rating of the accident was raised to the same as Chernobyl nearly one month ago. The station is located about 220 kilometers (137 miles) north of Tokyo. Flooding the containment chamber was one of the steps Tepco outlined in April to bring the crisis under control. “The plan needs to be revised,” Matsumoto said. “We can’t deny the possibility that a hole in the pressure vessel caused water to leak.”
The surface temperature of the pressure vessel is between 100 and 120 degrees Celsius (248 Fahrenheit), meaning melted fuel is still getting cooled by steam and water, Matsumoto said. The utility discovered the water levels in the reactor vessel were lower than thought after repairing a gauge on May 10, Takeo Iwamoto, spokesman at Tepco, said by telephone today. Workers last week started entering the No. 1 reactor building for the first time since a blast destroyed its roof. Thereâ€™s no danger of another hydrogen blast, Matsumoto said at the briefing. Tepco expects a sustained drop in radiation levels at the entire plant by July, according to the plan announced on April 17. Following that, a cold shutdown of reactors No. 1, 2 and 3 may take place as early as October, the utility said at the time. To contact the reporters on this story: Michio Nakayama in Tokyo at email@example.com; Tsuyoshi Inajima in Tokyo at firstname.lastname@example.org To contact the editor responsible for this story: Amit Prakash at email@example.com -0May/12/ :31 GMT ÂŽ2011 BLOOMBERG L.P. ALL RIGHTS RESERVED.