42 U.S.C. § 2164

(a) By Commission The President may authorize the Commission to cooperate with another nation and to communicate to that nation Restricted Data on— (1) refining, purification, and subsequent treatment of source material; (2) civilian reactor development; (3) production of special nuclear material; (4) health and safety; (5) industrial and other applications of atomic energy for peaceful purposes; and (6) research and development relating to the foregoing: Provided, however , That no such cooperation shall involve the communication of Restricted Data relating to the design or fabrication of atomic weapons: And provided further , That the cooperation is undertaken pursuant to an agreement for cooperation entered into in accordance with section 2153 of this title , or is undertaken pursuant to an agreement existing on August 30, 1954 . (b) By Department of Defense The President may authorize the Department of Defense, with the assistance of the Commission, to cooperate with another nation or with a regional defense organization to which the United States is a party, and to communicate to that nation or organization such Restricted Data (including design information) as is necessary to— (1) the development of defense plans; (2) the training of personnel in the employment of and defense against atomic weapons and other military applications of atomic energy; (3) the evaluation of the capabilities of potential enemies in the employment of atomic weapons and other military applications of atomic energy; and (4) the development of compatible delivery systems for atomic weapons; whenever the President determines that the proposed cooperation and the proposed communication of the Restricted Data will promote and will not constitute an unreasonable risk to the common defense and security, while such other nation or organization is participating with the United States pursuant to an international arrangement by substantial and material contributions to the mutual defense and security: Provided, however , That the cooperation is undertaken pursuant to an agreement entered into in accordance with section 2153 of this title . (c) Exchange of information concerning atomic weapons; research, development, or design, of military reactors In addition to the cooperation authorized in subsections (a) and (b), the President may authorize the Commission, with the assistance of the Department of Defense, to cooperate with another nation and— (1) to exchange with that nation Restricted Data concerning atomic weapons: Provided , That communication of such Restricted Data to that nation is necessary to improve its atomic weapon design, development, or fabrication capability and provided that nation has made substantial progress in the development of atomic weapons; and (2) to communicate or exchange with that nation Restricted Data concerning research, development, or design, of military reactors, whenever the President determines that the proposed cooperation and the communication of the proposed Restricted Data will promote and will not constitute an unreasonable risk to the common defense and security, while such other nation is participating with the United States pursuant to an international arrangement by substantial and material contributions to the mutual defense and security: Provided, however , That the cooperation is undertaken pursuant to an agreement entered into in accordance with section 2153 of this title . (d) By Department of Energy (1) In addition to the cooperation authorized in subsections (a), (b), and (c), the President may, upon making a determination described in paragraph (2), authorize the Department of Energy, with the assistance of the Department of Defense, to cooperate with another nation to communicate to that nation such Restricted Data, and the President may, upon making such determination, authorize the Department of Defense, with the assistance of the Department of Energy, to cooperate with another nation to communicate to that nation such data removed from the Restricted Data category under section 2162 of this title , as is necessary for— (A) the support of a program for the control of and accounting for fissile material and other weapons material; (B) the support of the control of and accounting for atomic weapons; (C) the verification of a treaty; and (D) the establishment of international standards for the classification of data on atomic weapons, data on fissile material, and related data. (2) A determination referred to in paragraph (1) is a determination that the proposed cooperation and proposed communication referred to in that paragraph— (A) will promote the common defense and security interests of the United States and the nation concerned; and (B) will not constitute an unreasonable risk to such common defense and security interests. (3) Cooperation under this subsection shall be undertaken pursuant to an agreement for cooperation entered into in accordance with section 2153 of this title . (e) Communication of data by other Government agencies The President may authorize any agency of the United States to communicate in accordance with the terms and conditions of an agreement for cooperation arranged pursuant to subsection (a), (b), (c), or (d), such Restricted Data as is determined to be transmissible under the agreement for cooperation involved.