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•• PREFACE Associated with commercial nuclear power production in the United States is the generation of potentially hazardous radioactive waste products. The • Department of Energy (DOE), through the National Waste Terminal Storage (NWTS) Program and the Office of Nuclear Waste Isolation (ONWI), is seeking to• develop nuclear waste isolation systems in geologic formations. These underground waste isolation systems will preclude contact with the biosphere of waste radionuclides in concentrations which are sufficient to cause deleterious impact on humans or their environments. Comprehensive analyses of specific isolation systems are needed to assess the post-closure expectations of the systems. The Assessment of Effectiveness of Geologic Isolation Systems (AEGIS) Program has been established for developing the capability of making those ana lyses.Among the analyses required for the system evaluation is the detailed assessment of the post-closure performance of nuclear waste repositories in geologic formations. This assessment is concerned with aspects of the nuclear program which previously have not been addressed. The nature of the isolation systems (e.g., involving breach scenarios and transport through the geosphere) and the great length of time for which the wastes must be controlled dictate the development, demonstration, and application of novel assessment capabilities. The assessment methodology must be thorough, flexible, objective, and scientifically defensible. Furthermore, the data utilized must be accurate, documented, reproducible, and based on sound scientific principles.The current scope of AEGIS is limited to long-term, post-closure analyses. It excludes the consideration of processes that are induced by the presence of the wastes, and it excludes the consideration of nuclear waste isolation in media other than geologic formations. The near-field/near-term aspects of geologic repositories are being considered by ONWI/DOE under separate programs. They will be integrated with the AEGIS methodology for the actual site-specific repository safety analyses • iii The assessment of repository post-closure safety has two basic components:• identification and analyses of breach scenarios and the pattern of events and processes causing each breach; • identification and analyses of the environmental consequences of radionuclides transport and interactions subsequent to a repository breach.The Release Scenario task is charged with identifying and analyzing breach scenarios and their associated patterns of events and processes.The Release Scenario task is concerned with evaluating the geologic system surrounding an underground repository and describing the phenomena which alone , or in concert could perturb the system and possibly cause 'a loss of repository integrity. Output from the Release Scenario task will establish the boundary conditions of the geology and hydrology surrounding the repository at the time of an identified breach. These bounding conditions will be used as input for the consequence analysis...

The purpose of this study was tp assist the Department of Energy (DOE) in determining the physical and economic availbility of land and water resources for energy farming. Ten water subbasins possessing favorable land and water availabilities were ranked,,acc.ord,ing to their •overall potential for biomas•s production. The study results cl~arly identify the Southeast as a favorable area for biomass farming. The Northwest and North-Central United States should alsu b~ consid~red on the basis of. t~eir highly favorable environmental characteristics. SRI prepared both high and low. e~timates of water availability for 1985 and 2000 iri each qf 99 subbasins. For the high (optimistic) estimate of water ~vailability (assuming instream flow requirements are 50% of u.s. Fish and Wildlife Service estimates in the year 2000), 6 subbasins are projected to have an excess supply of more than 50 trillion gallons per day, and 12• subbasins to have no excess supply. For the low (pessimistic) estimate (80% of USFWS estimates), 31 subbasins have no excess supply, 32 subbasins have excesses of 1 to 5 trillion gallons per day, and 36 subbasins have more than 5 trillion gallons per day of excess supply; only * References for each section of this report are listed at the end of the sections in which they are cited.

TMs report w a~ pmpamd us an Paxwnt of rrvork m s a r e d by the United States Oouemment Neither the United States nor the E m UesOurch end Davebpment Administrotion. nor any of thek employsse, nor my of their conWactom, mbeantr~ctors, or their amplayeas, maices any wamnty, exwetis or implied, or securmcn, any kgal liability or mmpomeibllity for the Pccurocy, ampktenees or ummne~8 d m y hformatim, swpwatue, product or pro-s d i -or -t r thst its use wouki not infringe pivateiy owned rights.

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