The purpose of this calculation is to characterize the criticality safety concerns for the codisposal of Shippingport pressurized water reactor (SP PWR) spent nuclear fuel (SNF) contained in a standardized Department of Energy (DOE) SNF canister, and high-level waste (HLW) glass in a waste package (WP) placed in a Monitored Geologic Repository (MGR). The result of this calculation will be used to evaluate criticality issues and provide input for the DOE SNF canister design, referred to as "the canister" in this document.

This design calculation is a revision of the previous criticality evaluation of the operations and
processes that are performed in the Aging Facility. It will also demonstrate and assure that the
storage and aging operations to be performed in the Aging Facility meet the criticality safety
design criteria in the Project Design Criteria Document (BSC 2005i, Section 4.9.2.2), and the
nuclear criticality safety requirements described in the SNF Aging System Description Document

The purpose of this calculation is to characterize the criticality aspect of the codisposal of TRIGA (Training, Research, Isotopes, General Atomic) reactor spent nuclear fuel (SNF) with Savannah River Site (SRS) high-level waste (HLW). The TRIGA SNF is loaded into a Department of Energy (DOE) standardized SNF canister which is centrally positioned inside five-canister defense SRS HLW waste package (WP). The objective of the calculation is to investigate the criticality issues for the WP containing the five SRS HLW and DOE SNF canisters in various stages of degradation.

This report has been prepared to support technical discussion of and planning for future
research supporting implementation of burnup credit for boiling-water reactor (BWR) spent fuel
storage in spent fuel pools and storage and transport cask applications. The review and
discussion in this report are based on knowledge and experience gained from work performed
in the United States and other countries, including experience with burnup credit for
pressurized-water reactor (PWR) spent fuel. Relevant physics and analysis phenomena are

This report proposes and documents a computational benchmark for the estimation of the
additional reactivity margin available in spent nuclear fuel (SNF) from fission products and minor
actinides in a burnup-credit storage/transport environment, relative to SNF compositions
containing only the major actinides. The benchmark problem/configuration is a generic burnupcredit
cask designed to hold 68 boiling water reactor (BWR) spent nuclear fuel assemblies. The
purpose of this computational benchmark is to provide a reference configuration for the