The Japanese operator of the tsunami-wrecked Fukushima Daiichi nuclear power plant on Tuesday said the start of full-scale removal of melted fuel debris will be delayed for several years until 2037 or later, the latest setback underscoring the challenges ahead. The Tokyo Electric Power Company Holdings, or TEPCO, said it will need 12 to 15 years of preparation before starting full-scale removal of melted fuel debris at the No. 3 reactor. Overall, at least 880 tons of melted nuclear fuel has mixed with broken parts of internal structures and other debris inside the three reactors that suffered meltdowns at the plant following the 2011 earthquake and tsunami.