Melted fuel from U.S. nuclear accident may help Japanese efforts

March 07, 2012

By NAOYA KON / Staff Writer

The Japan Atomic Energy Agency said on March 5 melted nuclear fuel from the 1979 accident at the U.S. Three Mile Island power plant in its possession may be analyzed to help prepare for the decommissioning of the crippled Japanese reactors.

The agency is considering a new round of analysis of the melted fuel for hints on how to go about dismantling the crippled reactors at the Fukushima No. 1 nuclear power plant.

“We want to use (the findings) to develop the technology to retrieve the melted fuel at the Fukushima plant and dispose of it,” said Fumihisa Nagase, leader of the Fuel Safety Research Group at the JAEA’s Nuclear Safety Research Center.

The agency's Nuclear Science Research Institute in Tokai village in Ibaraki Prefecture was provided the melted fuel by the Idaho National Laboratory, the U.S. Department of Energy’s nuclear and energy research facility, in 1991.

The melted fuel--60 fragments weighing about 3 kilograms in total--was given as part of an international project to jointly study the material. It is stored in a container in a pool to shield radiation.

Some of the fragments are dark blocks that resemble melted rock from volcanic eruptions, while other pieces look like sand and some are in the form of dark blocks with metal particles attached.

The main components that make up the fragments are uranium compounds, which also contain zirconium, used to make the cladding tubes that encased the nuclear fuel.

Some of the nuclear fuel at the Fukushima No. 1 plant is believed to have eaten into the reactors’ containment vessels after it melted through pressure vessels as a result of the failure of cooling systems.

In the accident at the Three Mile Island plant, a partial meltdown occurred at the Unit 2 reactor after its cooling system malfunctioned, culminating in the most serious nuclear accident in the United States.

By NAOYA KON / Staff Writer
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Part of the melted nuclear fuel from the accident at the U.S. Three Mile Island nuclear power plant (Provided by the Japan Atomic Energy Agency)

Part of the melted nuclear fuel from the accident at the U.S. Three Mile Island nuclear power plant (Provided by the Japan Atomic Energy Agency)

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  • Part of the melted nuclear fuel from the accident at the U.S. Three Mile Island nuclear power plant (Provided by the Japan Atomic Energy Agency)
  • A cross-section view of melted nuclear fuel. The part that looks green is uranium dioxide and the part appearing brown contains zirconium, iron, nickel and other metals. (Provided by the Japan Atomic Energy Agency)

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