The Commission is authorized, to the extent it deems necessary to effectuate the provisions of this chapter, to purchase without regard to the limitations in section 2074 of this title or any guaranteed purchase prices established pursuant to section 2076 of this title, and to take, requisition, condemn, or otherwise acquire any special nuclear material or any interest therein. Any contract of purchase made under this section may be made without regard to the provisions of section 6101 of title 41, upon certification by the Commission that such action is necessary in the interest of the common defense and security, or upon a showing by the Commission that advertising is not reasonably practicable. Partial and advance payments may be made under contracts for such purposes. Just compensation shall be made for any right, property, or interest in property taken, requisitioned, or condemned under this section: Providing, That the authority in this section to commit United States funds for any activities pursuant to any subsequent arrangement under section 2160(a)(2)(E) of this title shall be subject to the requirements of section 2160 of this title.