The preclosure criticality analysis process described in this technical report provides a systematic approach for determining the need for criticality controls and for evaluating their effectiveness during the preclosure period of the Monitored Geologic Repository at Yucca Mountain, Nevada.

The objectie of this calculation is to document the Grand Gulf, Unit 1, (GG1) fuel depletion calculations. The GG1 reactor is a boiling water reactor (BWR) owned and operated by Entergy Operations Inc. The Commercial Reactor Criticality (CRC) evaluations support the development and validation of the neutronic models used for criticality analyses involving commercial spent nuclear fuel in a geologic repository. This calculation is performed as part of the evaluation CRC program. This report is an engineering calculation supporting the burnup credit methodology of YMP 2000 (Ref.

The purpose of this calculation is to develop axial profiles for estimating the axial variation in burnup of a boiling water reactor (BWR) assembly spent nuclear fuel (SNF) given the average burnup of an assembly. A discharged fuel assembly typically exhibits higher burnup in the center and lower burnup at the ends of the assembly. Criticality safety analyses taking credit for SNF burnup must account for axially varying burnup relative to calculations based on uniformly distributed assembly average burnup due to the under-burned tips.

The purpose of this analysis is to identify, extract, and reformat weather (meteorological) data that is appropriate for use as input to an infiltration model, within the Yucca Mountain region. The analysis uses relevant meteorological data (e.g., precipitation and temperature) from source stations, and reformats or converts the data into a form suitable for the generation of meteorological conditions for a 10,000-year future climate in the Yucca Mountain region.

The purpose of this analysis is to document the MCNP evaluations of benchmark lattice Laboratory Critical Experiments (LCE's). The objective of this analysis is to quantify the MCNP 4A (Reference 5.4) code system's ability to accurately calculate the effective neutron multiplication factor (keff) for various measured critical (i.e., keff= 1.0) configurations. This analysis quantifies the effectiveness of the MCNP criticality calculation for lattice configurations containing U02 and Pu02 fissile oxide fuel using two different cross section data libraries.

The purpose of this calculation is to perform waste-form specific nuclear criticality safety calculations to aid in establishing criticality safety design criteria, and to identify design and process parameters that are potentially important to the criticality safety of the transportation, aging and disposal (TAD) canister-based systems.

The objective of the Limerick Unit 1 Radiochemical Assay Comparisons to SAS2H Calculations is to determine the accuracy of the SAS2H control module of the baselined modular code system SCALE, Version 4.4A (STN: 10129-4.4A-00), in predicting the isotopic concentrations of spent fuel, and to quantify the overall effect that the differences between the calculated and measured isotopic concentrations have on the system reactivity. The scope of this calculation covers eight different spent fuel samples from a fuel assembly that was irradiated in the Limerick Unit 1 boiling water reactor (BWR).

The purpose of this analysis is to evaluate the transient behavior and consequences of a worst case criticality event involving intact pressurized water reactor (PWR) spent nuclear fuel (SNF) in a degraded basket configuration inside a 21 PWR assembly waste package (WP). The objective of this analysis is to demonstrate that the consequences of a worst case criticality event involving intact PWR SNF are insignificant in their effect on the overall radioisotopic inventory in a WP. An internal WP criticality is modeled in a manner analogous to transient phenomena in a nuclear reactor core.