Bunker Buster Act This bill authorizes the President take certain actions to help Israel prepare for all contingencies if Iran seeks to develop a nuclear weapon, if certain conditions are met. The President may take such actions, including storing in Israel large ordnance systems designed to destroy underground nuclear infrastructure or supporting infrastructure construction in Israel to accommodate such ordnance systems only if, among other requirements, the President certifies to Congress that the action is vital to U.S. national security interests. The President may transfer such ordnance systems to Israel upon making additional certifications, including a certification that Israel has no other means of destroying Iran's underground nuclear infrastructure.