DUBAI, United Arab Emirates (AP) — A secretive Israeli nuclear facility at the center of the nation’s undeclared atomic weapons program is undergoing what appears to be its biggest construction project in decades. That’s according to satellite photos analyzed by The Associated Press. A dig about the size of a soccer field and likely several stories deep now sits just meters from the aging reactor at the Shimon Peres Negev Nuclear Research Center near the city of Dimona. What the construction is for, however, remains unclear. The Israeli government did not respond to detailed questions from the AP about the work.