became one of Mandil's key reactor material engineers. Scott later completed what was an equivalent to a doctorate in nuclear engineering at the Oak Ridge National Laboratory in Tennessee, but due to the classified nature of the work, a formal university degree was not awarded. He also worked on the development of the Shippingport Atomic Power Station—the first commercial land-based nuclear power plant. He worked with Rickover until 1965 when he and his family moved to Córdoba, Argentina, when he was called as president of the church's Argentina North Mission. One of his missionaries was D. Todd Christofferson, who would later be called to serve in the Quorum of the Twelve with Scott. After his return from Argentina, Scott joined other former Rickover staffers at a private consulting firm specializing in nuclear engineering, working out of Washington, D.C. He worked there until his call as a church general authority in 1977. LDS Church service Scott served in the LDS Church in many capacities. His ability to speak Spanish aided him in many assignments. Apart from his 31-month mission to Uruguay, he served as a stake clerk and as a counselor in a stake presidency before his service as a mission president. He served as a regional representative in the Uruguay, Paraguay, North Carolina, South Carolina, Virginia, and Washington, D.C. areas. He was called as a general authority and member of the First Quorum of the Seventy in April 1977. In 1983, he was called to the Presidency of the Seventy. As a seventy, Scott served as managing director of the Genealogical Department and Executive Administrator of the church for Southern Mexico and Central America. On October 1, 1988, Scott was called to serve in the Quorum of the Twelve Apostles, filling the vacancy created by the death of quorum president Marion G. Romney. As a member of the Quorum of the Twelve, Scott was accepted by the church as a prophet, seer, and revelator. After not speaking in the church's general conference earlier in the month, on April 23, 2015, Scott was hospitalized with gastrointestinal bleeding. The bleeding was brought under control within the next 24 hours, and he was released from the hospital on April 28. The bleeding was later determined to have been caused by an ulcer. The church reported that "Elder Scott, known for his gentle manner and devoted service, has experienced a fading memory incident to