“ By the authority vested in me as President by the Constitution and laws of the United States of America, including section 126a (2) of the Atomic Energy Act of 1954, as amended (42 U.S.C. 2155 (a) (2) ) , and having determined that, upon the expiration of the period specified in the first proviso to section 126a (2) of such Act and extended for 12-month periods by Executive Orders Nos. ”