The Associated Press is reporting the Bush administration has halted research into controversial “bunker buster” nuclear weaponry. Republican senator Pete Domenici said a budget request for the weapons research has been dropped. The idea fueled concerns it would spread nuclear proliferation. Administration officials say they will instead pursue a non-nuclear bunker buster. Stephen Young, a senior analyst for the Union of Concerned Scientists, praised the decision, saying: “The proposed weapon, more than 70 times the size of the bomb dropped on Hiroshima, would have caused unparalleled collateral damage.”