The "Summary Report of Commercial Reactor Criticality Data for Davis-Besse Unit 1" contains the detailed information necessary to perform commercial reactor criticality (CRC) analyses for the Davis-Besse Unit 1 reactor.

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.

The "Summary Report of Commercial Reactor Criticality Data for Catawba Unit 1" contains the detailed information necessary to perform commercial reactor criticality (CRC) analyses for the Catawba Unit 1 reactor.

Taking credit for the reduced reactivity of spent nuclear fuel in criticality analyses is referred to
as burnup credit. Criticality safety evaluations employing burnup credit require validation of the
depletion and criticality calculation methods and computer codes with available measurement
data. To address the issues of burnup credit criticality validation, the U.S. Nuclear Regulatory
Commission initiated a project with Oak Ridge National Laboratory to (1) develop and establish

The Office of Civilian Radioactive Waste Management (OCRWM) is responsible for all spent fuels and high-level wastes (HLW) that will eventually be disposed of in a geologic repository. The purpose of this document, and the information contained in the associated computerized data bases and supporting technical reports, is to provide the technical characteristics of the radioactive waste materials that will (or may) be accepted by DOE for interim storage in an MRS or emplacement in a repository as developed under the Nuclear Waste Policy Act Amendment of 1987.

The "Summary Report of Commercial Reactor Criticality Data for LaSalle Unit 1" contains the detailed information necessary to perform commercial reactor criticality (CRC) analyses for the LaSalle Unit 1 (LS 1) reactor.

The Disposal Subcommittee of the Blue Ribbon Commission on America’s Nuclear Future (BRC) addressed a wide-ranging set of issues, all bearing directly on the central question: “How can the United States go about establishing one or more disposal sites for high-level nuclear wastes in a manner and within a timeframe that is technically, socially, economically, and politically acceptable?”

The purpose of this calculation is to simulate the processing of an incoming waste stream into waste packages, simulating the required aging as applicable, and the emplacement of the waste packages into the Yucca Mountain repository.

The Nuclear Waste Policy Act of 1982, as amended (NWPA), establishes a process for the siting, construction and operation of one or more national repositories for permanent disposal of the Nation’s spent nuclear fuel (SNF) and high-level radioactive waste (HLW). In 1987, after the Department of Energy (the Department or DOE) had conducted studies of nine potential repository sites located throughout the United States, Congress amended the NWPA and selected the Yucca Mountain site in Nye County, Nevada as the only site for further study for the first national repository.

The Nuclear Waste Policy Act of 1982 (the Act), established a
step-by-step process for the siting of the nation's first repository for
high-level radioactive waste and spent fuel. The Act gave the Department of
Energy (DOE) the primary responsibility for conducting this siting process.
The first step in the process laid out in the Act was the development by
the DOE, with the concurrence of the Nuclear Regulatory Commission (NRC), of
general guidelines to be used by the Secretary of the DOE (the Secretary) in

Confidence in the long-term safety of deep geological disposal, and the ways in which this
confidence can be obtained and communicated, are topics of great importance to the radioactive waste
management community.1
The technical aspects of confidence have been the subject of considerable debate, especially
the concept of model validation. It has, for example, been pointed out that it is impossible to describe
fully the evolution of an open system, such as a repository and its environment, that cannot be

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

The Department of Energy (DOE), pursuant to the Atomic Energy Act of 1954
as amended, the Energy Reorganization Act of 1974, the Department of Energy
Organization Act of 1977, and the Nuclear Waste Policy Act of 1982 (the Act),
has the responsibility to provide for the disposal of high-level radioactive
waste and spent nuclear fuel.* The DOE selected mined geologic repositories
as the preferred means for the disposal of commercially generated high-level
radioactive waste and spent fuel (Federal Register, Vol. 46, p. 26677, May 14,

Pressurized water reactor (PWR) burnup credit validation is
demonstrated using the benchmarks for quantifying fuel reactivity
decrements, published as Benchmarks for Quantifying Fuel Reactivity
Depletion Uncertainty, Electric Power Research Institute (EPRI)
report 1022909. This demonstration uses the depletion module
TRITON (Transport Rigor Implemented with Time-Dependent
Operation for Neutronic Depletion) available in the SCALE 6.1
(Standardized Computer Analyses for Licensing Evaluations) code

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.

In June 2008, the U.S. Department of Energy (DOE) submitted a license application to the U.S. Nuclear Regulatory Commission (NRC) for the construction of a geologic repository at Yucca Mountain, Nevada, for the disposal of spent nuclear fuel and high-level radioactive waste. The license application was accepted for formal NRC review in September 2008. Throughout the more than 20-year history of the Yucca Mountain project, EPRI has performed independent assessments of key technical and scientific issues to facilitate an understanding of overall repository performance.

There has been a resurgence of interest in the possibility of processing the US spent nuclear fuel, instead of burying it in a geologic repository. Accordingly, key topical findings from three relevant EPRI evaluations made in the 1990-1995 timeframe are recapped and updated to accommodate a few developments over the subsequent ten years. Views recently expressed by other US entities are discussed.

Since 1989, EPRI has been conducting independent assessments of the proposed deep geologic repository for the disposal of spent nuclear fuel and high level radioactive waste at Yucca Mountain, Nevada. EPRI pioneered application of the total system performance assessment (TSPA) approach for evaluating performance of geologic repository systems on a probabilistic basis. Along the way, EPRI developed the Integrated Multiple Assumptions and Release Code (IMARC) as its primary analytical tool for TSPA-based evaluations.

The effective termination of the Yucca Mountain program by the U.S. Administration in 2009
has left the U.S. program for management of used fuel and high level radioactive waste (HLW)
in a state of uncertainty. In concert with this major policy reset and in response to the resulting
policy vacuum, the President directed the Energy Secretary to establish the Blue Ribbon
Commission on America’s Nuclear Future (BRC) “…to conduct a comprehensive review of
policies for managing the back end of the nuclear fuel cycle and to provide recommendations for

U.S. efforts to site and construct a deep geologic repository for used fuel and high level
radioactive waste (HLW) proceeded in fits and starts over a three decade period from the late
1950s until 1982, when the U.S. Congress enacted the Nuclear Waste Policy Act (NWPA). This
legislation codified a national approach for developing a deep geologic repository. Amendment
of the NWPA in 1987 resulted in a number of dramatic changes in direction for the U.S.
program, most notably the selection of Yucca Mountain as the only site of the three remaining

The Disposal Subcommittee of the Blue Ribbon Commission on America’s Nuclear Future has
commenced to address a set of issues, all of which bear directly on the central question: “How can the
United States go about establishing one or more disposal sites for high-level nuclear wastes in a manner
and within a timeframe that is technically, socially, economically, and politically acceptable?”
To answer this question and to develop specific recommendations and options for consideration by the