Three reactors at Japan’s stricken power plant have melted fuel rods and it may take longer than nine months to gain control at the site, said William Ostendorff, a member of the U.S. Nuclear Regulatory Commission.
About 55 percent of the radioactive fuel rods in the Unit 1 reactor at Tokyo Electric Power Co.’s Fukushima Dai-Ichi plant melted after a March 11 earthquake and tsunami, Ostendorff said. About 30 percent of the rods in unit 2 and 35 percent of the fuel in reactor 3 also melted, he said at a hearing of the Senate Environment and Public Works Committee.
The Japanese utility is trying to put the reactors into a cold shutdown, where core temperatures fall below 100 degrees Celsius (212 degrees Fahrenheit). Senator Barbara Boxer, a California Democrat and committee chairman, said the plan calls for a shutdown within six to nine months. Ostendorff said chance of meeting the goal, on a 10-point scale, is six or seven.
The NRC is conducting a safety review of U.S. reactors to determine if tougher regulations are needed. The agency may have a draft report ready by mid-July, Ostendorff said. The failure of pressure-relieving venting systems at the Japan plant is a “key part” of the review, he said.
“If we need to make changes to our regulatory framework as a result of this accident, we will,” Ostendorff said.
Entergy Corp., the second-largest U.S. nuclear operator, and Duke Energy Corp. have said U.S. reactor owners may need to retrofit their plants or bolster safety systems after the failure of the Fukushima vents. The venting systems let engineers release pressurized gas to avoid dangerous hydrogen explosions during a reactor accident.
The disaster in Japan destroyed power lines and diesel generators at the Fukushima plant, depriving cooling systems of electricity. Fuel rods overheated, causing fires, explosions and radiation leaks in the worst nuclear accident since the 1986 Chernobyl disaster.
There are probably holes in the containment chambers of the three damaged reactors at the Fukushima site, Tokyo Electric said today, citing computer simulations.
Ostendorff testified today at a hearing on his nomination to a full, five-year term at the NRC. President Barack Obama appointed Ostendorff last year to replace Dale Klein, who resigned before the June 30 expiration of his term. Klein was chairman of the NRC under President George W. Bush. Obama has asked the Senate to vote to keep Ostendorff on the commission.