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 Department of Energy (DOE) standardized Spent Nuclear Fuel (SNF) canisters.

The purpose of this document is to present the methodology to be used for development of the Subcritical Limit (SL) for post closure conditions for the Yucca Mountain repository. The SL is a value based on a set of benchmark criticality multiplier, keff> results that are outputs of the MCNP calculation method. This SL accounts for calculational biases and associated uncertainties resulting from the use of MCNP as the method of assessing kerr·

The Total System Model (TSM) 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), U.S. Department of Energy (DOE) spent nuclear
fuel (DOE SNF), and defense high-level (radioactive) waste (HLW). The TSM uses a TSM
Preprocessor (TSMPP) to generate the cask loads and target dates for shipments from waste
sites. The TSM then tracks these wastes from pickup at the waste sites until repository

The purpose of the material degradation and release (MDR) model is to predict the fate of the waste package materials, specifically the retention or mobilization of the radionuclides and the neutron-absorbing material as a function of time after the breach of a waste package during the 10,000 years after repository closure. The output of this model is used directly to assess the potential for a criticality event inside the waste package due to the retention of the radionuclides combined with a loss of the neutron-absorbing material.

This validation report supports the issuance of the Total System Model (TSM) Version 6.0 (Bechtel SAIC, LLC (BSC) 2007a) that is described in the TSM User Manual (UM) (BSC 2007b) and the TSM Pre-Processor (TSMPP) UM (BSC 2007c), and other supporting documentation in References BSC 2007d, BSC 2007e, 2007f, and 2007g. This report assumes the reader has detailed, working knowledge of the TSM functions and Civilian Radioactive Waste Management System (CRWMS) operations.

The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments.

Japan’s spent fuel management and fuel cycle programs are now at a critical stage. Its first commercial-scale reprocessing plant, at Rokkasho Village, will soon start full-scale operation.

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 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.

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.

Presented at the NEI Used Fuel Management Conference, St. Petersburg, FL, May 7-9, 2013

Since a 1985 decision by President Reagan that a separate permanent repository for disposal of
defense high level waste was not required1, DOE has planned for disposal of all high-level waste
and spent fuel from national defense activities and DOE’s own research activities in a repository
for commercial waste developed under the Nuclear Waste Policy Act (NWPA). The Commission
has heard recommendations from some commenters2 that this decision be revisited, or even

The purpose of this report is to document the calibrated property sets for unsaturated zone (UZ) flow and transport process models (UZ models). The calibration of the property sets is performed through inverse modeling using a previously validated model. This work followed, and was planned in Technical Work Plan for: Unsaturated Zone Flow, Drift Seepage and Unsaturated Zone Transport Modeling (BSC 2006 [DIRS 177465], Sections 1 and 2.1.2).

The Monitored Geologic Repository Waste Package Operations of the Civilian Radioactive Waste Management System Management & Operating Contractor (CRWMS M&O) performed calculations to provide input for disposal of spent nuclear fuel (SNF) from the Navy (Refs. 1 and , 2). The Navy SNF has been considered for disposal at the potential Yucca Mountain site. For some waste packages, the containment may breach (Ref. 3), allowing the influx of water. Water in the waste package may moderate neutrons, increasing the likelihood of a criticality event within the waste package.

This report evaluates the potential for directly disposing of licensed commercial Dual Purpose
Canisters (DPCs) inside waste package overpacks without reopening. The evaluation considers
the principal features of the DPC designs that have been licensed by the Nuclear Regulatory
Commission (NRC) as these relate to the current designs of waste packages and as they relate to
disposability in the repository. Where DPC features appear to compromise future disposability,
those changes that would improve prospective disposability are identified.

The search for sites for radioactive waste management (RWM) facilities attracts attention from implementers, government bodies, local communities, and the public at large. Facility siting processes, in general, tend to be marred by conflicts, disagreements, and delays.