This volume opens with a keynote lecture by Rodney Ewing, member of the Board of Radioactive Waste Management of the National Research Council. Ewing summarizes 25 years of materials research in nuclear waste, emphasizing the progress that has been made and the challenges that still confront investigators and technologists in materials science and repository performance evaluation. The session is followed by one on container materials and engineered barriers, and includes a discussion on the corrosion performance expected for waste packages in the proposed high-level nuclear waste repository at Yucca Mountain, Nevada. Invited papers on performance assessment and repository studies for different national programs are also highlighted, with representation from the United States, Sweden, Japan, Belgium, Switzerland, Italy, and the United Kingdom. A large number of papers focus on the structure, properties, and degradation of various waste forms such as glasses, ceramics (mostly for plutonium immobilization), cements, and spent nuclear fuel. For the second consecutive time, the number of papers on ceramics far exceeds those on glass, which had been the dominant material discussed at this symposium over the prior 23 years. New studies on zirconates confirm the recently discovered high radiation damage-resistance of this material. Additional topics include: performance assessment in high-level waste disposal; performance assessment in low-level waste disposal; ceramic structure and corrosion; radiation effects in ceramics; glass structure and corrosion; spent fuel; spent fuel cladding and alternative waste forms; cements in radioactive waste immobilization; contaminant transport; natural analogs; and waste processing.

The Symposium on the Scientific Basis for Nuclear Waste Manage ment was held in the fall of 1979 in Boston, Massachusetts and was one of a number of symposia included in the Annual Meeting of the Materials Research Society. The thrust of this annual Symposium is unique in the area of waste management. Recognizing that this is an area of great complexity which requires contributions from scien tists with many different backgrounds some of which are not normally associated with nuclear energy, the Materials Research Society pro vides a forum for discussions of a wide range of materials behavior and transport phenomena. As can be seen from the list of references in each paper, the authors draw heavily on contributions associated with professional societies in addition to the Materials Research Society, and this annual meeting encourages the cross-fertilization between disciplines that are essential to an adequate treatment of the problems associated with nuclear waste management. The proceed ings of the first Symposium that was held in 1978 was designated as Volume 1 in this series. The third Symposium is scheduled for 1980. The scope of the 1979 Symposium was guided by the Steering Committee: R. L. Schwoebel, Sandia Laboratories, USA (Chairman) W. Carbiener, Battelle Memorial Institute, Columbus, USA D. Ferguson, Oak Ridge National Laboratory, USA W. Heimerl, DWK, Mol, Belgium W. Lutze, Hahn Meitner Institut, Berlin, W. Germany J. D. Mather, Institute of Geological Sciences, Harwell, UK G. Oertel, Department of Energy, USA R.

During late 1978, a symposium entitled "Science Underlying Radioactive Waste Management" was one component of the Annual Meet ing of the Materials Research Society held in Boston, Massachusetts. The purpose of this Symposium was to bring together for the first time the entire range of sciences that form the basis for the treatment, solidification and isolation of radioactive wastes. Some 79 papers were presented to an international audience of over 300. The Symposium was such an impressive success that another will be held at the 1979 Annual Meeting of the Materials Research Society. The proceedings of the forthcoming symposium will also be published and it is for this reason that the present volume has been desig nated Volume 1. The scope of the Symposium was defined by the following steer ing committee: Rustum Roy, The Pennsylvania State University (Chairman) Richard S. Claassen, Sandia Laboratories Don Ferguson, Oak Ridge National Laboratory Victor I. Spitsyn, U.S.S.R. Academy of Sciences, Moscow David B. Stewart, United States Geological Survey Torbjorn Westermark, Royal Institute of Technology, Stockholm. The program was organized by the following committee: Gregory J. McCarthy, The Pennsylvania State University (Cha- man) Harry C. Burkholder, Battelle Memorial Institute Arnold M. Friedman~ Argonne National Laboratory Werner Lutze, Hahn-Meitner Institut, Berlin John G. Moore, Oak Ridge National Laboratory Robert W. Potter, II, United States Geological Survey Richard L. Schwoebe1, Sandia Laboratories Roger W. Staehle, Ohio State University.