Past efforts by the Department of Energy (DOE), the Electric Power Research Institute (EPRI), the Nuclear Regulatory Commission (NRC), and others have provided sufficient technical information to enable the NRC to issue regulatory guidance for implementation of pressurized-water reactor (PWR) burnup credit; however, consideration of only the reactivity change due to the major actinides is recommended in the guidance.

This report presents studies performed to support the development of a technically justifiable approach for
addressing the axial-burnup distribution in pressurized-water reactor (PWR) burnup-credit criticality
safety analyses. The effect of the axial-burnup distribution on reactivity and proposed approaches for
addressing the axial-burnup distribution are briefly reviewed. A publicly available database of profiles is
examined in detail to identify profiles that maximize the neutron multiplication factor, keff, assess its

This “Technical Evaluation Report on the Content of the U.S. Department of Energy’s Yucca Mountain License Application; Postclosure Volume: Repository Safety After Permanent Closure” (TER Postclosure Volume) presents information on the NRC staff’s review of DOE’s Safety Analysis Report (SAR), provided on June 3, 2008, as updated by DOE on February 19, 2009. The NRC staff also reviewed information DOE provided in response to NRC staff’s requests for additional information and other information that DOE provided related to the SAR.

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.

Presented at WM'03 Conference, Tucson, AZ, February 23-27, 2003

The report describes the final results of the Phase IIIB Benchmark conducted by the
Expert Group on Burnup Credit Criticality Safety under the auspices of the Nuclear Energy
Agency (NEA) of the Organization for Economic Cooperation and Development (OECD).
The Benchmark was intended to compare the predictability of current computer code and
data library combinations for the atomic number densities of an irradiated BWR fuel
assembly model. The fuel assembly was irradiated under specific power of 25.6 MW/tHM

This report presents a formal analysis of the five sites nominated as
suitable for characterization for the first repository; the analysis is based
on the information contained or referenced in the environmental assessments
that accompany the site nominations (DOE, 1986a-e). It is intended to aid in
the site-recommendation decision by providing insights into the comparative
advantages and disadvantages of each site. Because no formal analysis can
account for all the factors important to a decision as complex as recommending

This validation report supports the issuance of Version 6.0 of the Total System Model (TSM, BSC 2007a) that is described in the TSM User Manual (UM, BSC 2007b) and the TSM Preprocessor (TSMPP) User Manual (BSC 2007c). This report assumes the reader has detailed, working knowledge of the TSM functions and the Civilian Radioactive Waste Management System (CRWMS) operations. This report is based on an earlier document, Validation Report: Total System Model Version 5.0 Report Generators (BSC 2007d) that supported TSM Version 5.0.

The Total System Model Preprocessor (TSMPP) is a part of the Total System Model (TSM),
which is a PC-based simulator that is a decision aid to achieve overall Office of Civilian
Radioactive Waste Management (OCRWM) disposal objectives. The TSM is identified as Level
3, i.e., not Important To Safety (ITS) and not Important To Waste Isolation (ITWI), software in
the Bechtel SAIC Company, LLC (BSC) Controlled Software Report.
The TSMPP combines information about existing conditions, such as waste inventory estimates

The Civilian Radioactive Waste Management System (CRWMS) Total System Model (TSM), a
Level 3 software, is a planning tool that estimates the logistic and cost impacts of various
operational assumptions in accepting radioactive wastes. Waste forms currently tracked are
commercial spent nuclear fuel (CSNF), Department of Energy (DOE) spent nuclear fuel (DOE
SNF), Naval SNF, and high-level (radioactive) waste (HLW). The TSM simulates the actions for
Waste Acceptance (WA) from discharge to emplacement.