TOKYO - Tokyo Electric Power Co. Holdings Inc. began work Friday to insert a remote-controlled robotic arm into the containment vessel of the No. 2 reactor at the crippled Fukushima Daiichi nuclear power plant, in preparation for another attempt to retrieve melted fuel debris next year.

The arm, which had been folded up inside a metal box, was extended and its tip passed through a valve in a pipe leading to the containment vessel at 10 a.m., TEPCO said. It will enter the vessel through an opening, known as X-6, on its side.

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