The overall purpose of this study is to provide information and ,@dance to the Office of Environmental Management of the U.S. Department of Energy (DOE) about the level of characterization necessary to dispose of DOE-owned spent nuclear fuel (SNF). The disposd option modeled was codisposal of DOE SNF with defense high-level waste (DHLN). A specific goal was to demonstrate the influence of DOE SNF, expected to be minor, in a predominately commercial repository using modeling conditions similar to those currently assumed by the Yucca Mountain Project (YMP). A performance assessment (PA) was chosen as the method of analysis. The performance metric for this analysis (referred to as the 1997 PA) was dose to an individual; the time period of interest was 100,000 yr. Results indicated that cumulative releases of "Tc and 237Np (primary contributors to human dose) fiom commercial SNF exceed those of DOE SNF both on a per MTHM and per package basis. Thus, if commercial SNF can meet regulatory performance criteria for dose to an individual, then the DOE SM; can also meet the criteria. This result is due in large part to lower burnup of the DOE SNF (less time for irradiation) and to the DOE SNF's small percentage of the total activity (1.5%) and mass (3.8%) of waste in the potential repository. Consistent-with the analyses performed for the YMP, the 1997 PA assumed all cladding as failed, which also contributed to the relatively poor performance of commercial SNF compared to DOE SNF.September 30, 1998 i ..
PrefaceThis study, the 1997 performance assessment (1997 PA), evaluates whether spent nuclear fuel (SNF) owned by the Office of Environmental Management of the U. S. Department of Energy (DOE) performs noticeably better (or worse) than commercial SNF, and identifies important parameters that influence this performance after disposal. The latter results, in particular, are intended to help define appropriate requirements for waste characterization with regard to DOE-owned SNF being accepted for disposal. The study is part of a broader DOE program, the National Spent Nuclear Fuel Program, for developing a safe, cost-effective technical strategy for the interim management and ultimate disposition of the foreign and domestic spent nuclear fuel under the DOE'S jurisdiction. The DOE-owned SNF is currently stored at three primary sites (Idaho National Engineering and Environmental Laboratory [INEEL], the Hanford reservation, and the Savannah River plant) and several secondary DOE sites. The SNF originated in experimental, defense, and foreign reactors.
Organization of ReportThis report is a detailed account of the analysis design and results. The introductory chapter describes the analysis goals and approach, highlights some of the analysis decisions made during the assessment, and sets the stage for the data and concepts that are presented in later chapters. Chapter 2 provides information on the performance measures and assumptions made with regard to modeling style.The remaining chapters cover the tasks of performance...