By MARI YAMAGUCHI
OKUMA, Japan (AP) — Eleven years after the Fukushima Daiichi nuclear power plant was ravaged by a meltdown following a massive earthquake and tsunami, most of the radioactive debris blasted by hydrogen explosions has been cleared and torn buildings fixed. The plant now looks like a sprawling construction site. But massive amounts of radioactive melted fuel remain inside the reactors, and details of their state remain largely unknown. The challenge of removing the melted fuel from the reactors is so daunting that some experts now say that setting a completion target is impossible, especially without details about the waste’s final repository.