The "Summary Report of SNF Isotopic Comparisons for the Disposal Criticality Analysis Methodology" contains a summary of the analyses that compare SNF measured isotopic concentrations (radiochemical assays) to calculated SNF isotop~c concentrations (SAS2H module ·orScale4.3). The results of these analyses are used to support the validation of the isotopic models for spent commercial light water reactor (LWR) fuel.

This report evaluates the potential for directly disposing of licensed commercial Dual Purpose
Canisters (DPCs) inside waste package overpacks without reopening. The evaluation considers
the principal features of the DPC designs that have been licensed by the Nuclear Regulatory
Commission (NRC) as these relate to the current designs of waste packages and as they relate to
disposability in the repository. Where DPC features appear to compromise future disposability,
those changes that would improve prospective disposability are identified.

A methodology for performing and applying nuclear criticality safety calculations, for PWR spent nuclear fuel (SNF) packages with actinide-only burnup credit, is described. The changes in the U-234, U-235, U-236, U-238, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, and Am-241 concentration with burnup are used in burnup credit criticality analyses. No credit for fission product neutron absorbers is taken. The methodology consists of five major steps. (1) Validate a computer code system to calculate isotopic concentrations of SNF created during burnup in the reactor core and subsequent decay.

A methodology for performing and applying nuclear criticality safety calculations, for PWR spent nuclear fuel (SNF) packages with actinide-only burnup credit, is described. The changes in the U-234, U-235, U-236, U-238, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, and Am-241 concentration with burnup are used in burnup credit criticality analyses. No credit for fission product neutron absorbers is taken. The methodology consists of five major steps. (1) Validate a computer code system to calculate isotopic concentrations of SNF created during burnup in the reactor core and subsequent decay.

Independent spent fuel storage installations (ISFSIs) are currently licensed for 20 years. However, delays in developing permanent spent fuel disposal capability require continued ISFSI storage beyond the 20-year term. This report provides a technical basis for demonstrating the feasibility of extended spent fuel storage in ISFSIs.

The purpose of this report is to develop and analyze the Engineered Barrier System (EBS) Radionuclide Transport Abstraction Model, consistent with Level I and Level II model validation, as identified in Technical Work Plan for: Near-Field Environment: Engineered Barrier System: Radionuclide Transport Abstraction Model Report (BSC 2006 [DIRS 177739]). The EBS Radionuclide Transport Abstraction (or RTA) is the conceptual model used in the Total System Performance Assessment (TSPA) to determine the rate of radionuclide releases from the EBS to the unsaturated zone (UZ).

The U.S. Nuclear Regulatory Commission (NRC) is evaluating the safety and security of spent nuclear fuel (SNF) stored in dry casks for extended time periods before transportation to a location where the SNF is further processed or permanently disposed.

This topical report describes the approach to the risk-informed, performance-based methodology to be used for performing postclosure criticality analyses for waste forms in the Monitored Geologic Repository at Yucca Mountain, Nevada. The risk-informed, performance-based methodology will be used during the licensing process to demonstrate how the potential for postclosure criticality will be limited and to demonstrate that public health and safety are protected against postclosure criticality.

This report evaluates the potential for directly disposing of licensed commercial Dual Purpose
Canisters (DPCs) inside waste package overpacks without reopening. The evaluation considers
the principal features of the DPC designs that have been licensed by the Nuclear Regulatory
Commission (NRC) as these relate to thedesigns of waste packages and as they relate to
disposability in a repository in unsaturated volcanic tuff. Where DPC features appear to compromise future disposability in an unsaturated tuff (e.g., Yucca Mountain) repository