Presentation made at International Conference on The Management of Spent Nuclear Fuel from Nuclear Power Reactors, An Integrated approach to the Back-End of the Fuel Cycle (IAEA-CN-226). The purpose of the conference was to highlight the importance of an integrated long-term approach to the management of spent fuel from nuclear power reactors.

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.

This analysis provides information necessary for total system performance assessment (TSPA) for the license application (LA) to include the excess U.S. Department of Energy (DOE) plutonium in the form of mixed oxide (MOX) spent nuclear fuel and lanthanide borosilicate (LaBS) glass. This information includes the additional radionuclide inventory due to MOX spent nuclear fuel and LaBS glass and the analysis that shows that the TSPA models for commercial spent nuclear fuel (CSNF) and high-level waste (HLW) degradation are appropriate for MOX spent nuclear fuel and LaBS glass, respectively.

As part of the plutonium waste form development and down-select process, repository analyses have been conducted to evaluate the long-term performance of these forms for repository acceptance. Intact and degraded mode criticality analysis of the mixed oxide (MOX) spent fuel is presented in Volume I, while Volume II presents the evaluations of the waste form containing plutonium immobilized in a ceramic matrix.

The purpose of this analysis is to provide an initial radionuclide inventory (in grams per waste package) and associated uncertainty distributions for use in the Total System Performance Assessment for the License Application (TSPA-LA) in support of the license application for the repository at Yucca Mountain, Nevada. This document is intended for use in postclosure analysis only.

The means to prevent and control criticality must be addressed as part of the Preclosure Safety Analysis (PCSA) required for compliance with 10 CFR Part 63 [DIRS 180319], where the preclosure period covers the time prior to permanent closure activities. This technical report presents the nuclear criticality safety evaluation that documents the achievement of this objective.

The purpose of this report is to document calculations of the number of waste packages that could be damaged in a potential future igneous event intersecting a repository at YuccaMountain. The analyses include disruption from an igneous intrusion and from an igneous eruption. The analyses also support the evaluation of the potential consequences from a future event as part of the total system performance assessment (TSPA) for the license application for the Yucca Mountain Project.

This paper presents an assessment of the benefits for extended burnup credit in transporting
pressurized-water-reactor (PWR) spent nuclear fuel (SNF) in the United States. A prototypic 32-
assembly cask and the current regulatory guidance were used as bases for this assessment. By
comparing recently released PWR discharge data with actinide-only-based loading curves, this
evaluation shows that additional negative reactivity (through either increased credit for fuel burnup or

This report was developed in accordance with the requirements in Technical Work Plan for Postclosure Waste Form Modeling (BSC 2005 [DIRS 173246]). The purpose of the in-package chemistry model is to predict the bulk chemistry inside of a breached waste package and to provide simplified expressions of that chemistry as a function of time after breach to Total Systems Performance Assessment for the License Application (TSPA-LA).

The objective of Calculation of Isotopic Bias and Uncertainty for BWR SNF is to quantify the computational bias and uncertainty in the multiplication factor (keff) to be used for Boiling Water Reactor (BWR) spent nuclear fuel (SNF) burn-up credit. The scope of this bias and uncertainty determination covers 38 different radiochemical assay (RCA) spent fuel samples from 14 different fuel assemblies that were irradiated in four different BWRs. The irradiated fuel samples evaluated span an enrichment range of 2.53 weight percent U-235 through 3.95 weight percent U-235.

Following the proposals for nuclear fuel assurance of International Atomic Energy
Agency (IAEA) Director General Mohamed ElBaradei, former Russian President Vladimir V.
Putin, and U.S. President George W. Bush, joint committees of the Russian Academy of
Sciences (RAS) and the U.S. National Academies (NAS) were formed to address these and other
fuel assurance concepts and their links to nonproliferation goals. The joint committees also
addressed many technology issues relating to the fuel assurance concepts. This report provides

In July 1999, the U.S. Nuclear Regulatory Commission (NRC) Spent Fuel Project Office
(SFPO) issued Interim Staff Guidance 8 Revision 1 (ISG8R1) to provide recommendations for the use
of burnup credit in storage and transport of pressurized-water reactor (PWR) spent fuel. Subsequent to
the issuance of ISG8R1, the NRC Office of Regulatory Research (RES) has directed an effort to
investigate the technical basis for extending the criteria and recommendations of ISG8R1 to allow

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 report is to develop the summary cladding degradation abstraction that will be used in the Total System Performance Assessment for the License Application (TSPA-LA). Most civilian commercial nuclear fuel is encased in Zircaloy cladding. The analysis addressed in this report is intended to describe the postulated condition of commercial Zircaloy-clad fuel as a function of postclosure time after it is placed in the repository.

The purpose of this report is to evaluate the potential for penetration of the Alloy 22 (UNS N06022) waste package outer barrier by localized corrosion due to the deliquescence of soluble constituents in dust present on waste package surfaces. The results support a recommendation to exclude deliquescence-induced localized corrosion (pitting or crevice corrosion) of the outer barrier from the total system performance assessment for the license application (TSPA-LA).

The benefits of burnup credit and the technical issues associated with utilizing burnup credit in spent
nuclear fuel (SNF) casks have been studied in the United States for almost two decades. The issuance of the
U.S. Nuclear Regulatory Commission (NRC) staff guidance for actinide-only burnup credit in 2002 was a
significant step toward providing a regulatory framework for using burnup credit in transport casks. However,
adherence to the current regulatory guidance (e.g., limit credit to actinides) enables only about 30% of the existing

The purpose of this methods report is to document: (1) the origin, and the methods used in the development of a comprehensive list of features, events, and/or processes (FEPs) that could potentially affect the postclosure performance of the Yucca Mountain disposal system; (2) the methodology and guidance used to screen FEPs for inclusion or exclusion from Total System Performance Assessment for the License Application (TSPA-LA) analysis; (3) the methodology and guidance used to create scenario classes; and (4) compliance with NUREG-1804 (NRC 2003.

EPRI has discovered several aspects of the U.S Department of Energy (DOE) proposed design and operation of the Yucca Mountain repository that—if implemented as described in the license application (LA)—could result in unnecessary occupational health and safety risk to workers involved with repository-related activities. This report identifies key DOE conservatisms and focuses on the occupational risk consequences of the DOE's approach to the repository design, performance assessment, and operation.

The objective of this calculation is to determine the structural response of the 5-DHLW/DOE (Defense High Level Waste/Department of Energy) SNF (Spent Nuclear Fuel) Short Co-disposal Waste Package (WP) when subjected (while in the horizontal orientation emplaced in the drift) to a collision by a loaded (with WP) Transport and Emplacement Vehicle (TEV) due to an over-run. The scope of this calculation is limited to reporting the calculation results in terms of maximum total stress intensities (Sis) in the outer corrosion barrier (dCB).