Japan Nuclear Reactor Cores May Have Been Damaged

A fire and aftershocks struck the crippled Fukushima Dai-Ichi power plant today, as officials battling to prevent a nuclear meltdown said fuel rods at two reactors may have been damaged since last week’s record earthquake. Clouds of white smoke or steam started rising from reactor buildings at 10 a.m. and moving westward inland. Japan Chief Cabinet Secretary Yukio Edano said radiation levels at the plant rose at that time but have since fallen. About 70 percent of the uranium-plutonium fuel rods at the plant’s No. 1 reactor and a third of the No. 2 reactor’s fuel may have been impaired, Tokyo Electric Power Co. said.Radiation levels at the No. 4 reactor hampered efforts to confirm a fire that broke out this morning had been extinguished, a day after a similar blaze at the same structure. Prime Minister Naoto Kan, facing a nation reeling from its strongest earthquake on record, said yesterday the danger of further radiation leaks has increased at the nuclear complex, 135 miles north of Tokyo.

Temperatures in the spent fuel rod cooling pools of the shuttered No. 5 and No. 6 reactors were rising as of 7 a.m. today to about 60 degrees Celsius (140 degrees Fahrenheit), Tsuyoshi Makigami, head of nuclear maintenance at Tepco, said. The building that houses the inactive No. 4 reactor at the nuclear plant has two holes in it and water in the spent fuel pool may be boiling, Japan’s Nuclear and Industrial Safety Agency said yesterday.

Spent Fuel Rods

Exposed to air, the fuel bundles could chemically react with moisture, catch fire and spread radiation, said Edwin Lyman, a physicist with the Union of Concerned Scientists.

Conditions would become deadly for any worker trying to refill the pool with a fire hose, the standard solution, said David Lochbaum, director of nuclear safety for the Cambridge, Massachusetts-based watchdog group and a former staffer at the U.S. Nuclear Regulatory Commission.

Asia’s biggest utility reported yesterday that the containment chamber of the No. 2 reactor may be damaged after an explosion and radiation leakage was possible.

A Tokyo Electric worker at the Fukushima nuclear plant is being treated for radiation exposure, said Toshiriro Bannai, director of international affairs for the Tokyo-based agency. Tokyo Electric said it hadn’t decided whether to bring workers back after the utility evacuated 750 of its 800 employees following yesterday morning’s blast.

About 50 workers remained at the plant to manage the reactors, Hikaru Kuroda, head of nuclear maintenance at the Japanese utility, said yesterday.

Explosions

The latest incidents follow a blast at the No. 3 reactor March 14 after a buildup of hydrogen gas, and a similar explosion at the No. 1 reactor on March 12.

Japan informed the International Atomic Energy Agency about the explosion at the No. 2 reactor and reported a fire at the No. 4 unit’s spent fuel pond that released radioactivity directly into the atmosphere, the IAEA said in a statement yesterday.

About 140,000 people within a radius of 20 to 30 kilometers from the plant were ordered to stay indoors. The magnitude-9 March 11 temblor and subsequent tsunami have led to what Kan has called the country’s worst crisis since World War II.

The wind at the stricken plant is forecast to blow this morning to the south at 2 to 5 meters a second, Japan’s Meteorological Agency said. Later in the day, it’s expected to blow to the southeast at speeds of as much as 12 meters a second. The forecast, posted on the agency’s website, is as of 6 a.m. local time.

Tokyo Electric engineers restored water levels at the plant yesterday, helping drive down radiation after residents within 30 kilometers (19 miles) were ordered inside to avoid contamination.

To contact the reporters on this story: Tsuyoshi Inajima in Tokyo at tinajima@bloomberg.net; Michio Nakayama in Tokyo at mnakayama4@bloomberg.net

To contact the editor responsible for this story: Amit Prakash at aprakash1@bloomberg.net

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