Executive Order on Promoting Small Modular Reactors for National Defense and Space Exploration Posted on Section 1. Purpose. Nuclear energy is critical to United States national security. That is why I have taken a series of actions to promote its development and facilitate its use. On June 29, 2017, I announced an initiative to revive and expand the nuclear energy sector and directed a complete review of United States nuclear energy policy to help find new ways to revitalize this crucial energy resource. On July 12, 2019, I signed a Presidential Memorandum entitled “The Effect of Uranium Imports on the National Security and Establishment of the United States Nuclear Fuel Working Group,” with the goal of examining the current state of domestic nuclear fuel production and reinvigorating the nuclear fuel supply chain, consistent with United States national security and nonproliferation goals. On August 20, 2019, I signed National Security Presidential Memorandum-20, entitled “Launch of Spacecraft Containing Space Nuclear Systems,” calling for development and use of space nuclear systems to enable or enhance space exploration and operational capabilities.