The Nuclear Waste Technical Review Board (Board) submits this Report to the U.S. Congress and The Secretary of Energy in accordance with provisions of the Nuclear Waste Policy Amendments Act of 1987, Public Law 100-203, which requires the Board to report its findings and recommendations to Congress and the Secretary of Energy no less than two times each year. Congress created the Board to evaluate the technical and scientific validity of activities undertaken by the Secretary of Energy in characterizing a site at Yucca Mountain, Nevada, for its suitability as the location of a permanent repository for disposing of spent nuclear fuel and high-level radioactive waste. The Board also reviews the Department of Energy's (DOE) work related to the design of the repository and to the packaging and transport of spent fuel and high-level radioactive waste. In this report, the Board summarizes its major activities during calendar year 1999.