Dear Secretary Chu:
At the direction of the President, you charged the Blue Ribbon Commission on America’s
Nuclear Future with reviewing policies for managing the back end of the nuclear fuel
cycle and recommending a new plan. We thank you for choosing us to serve as Co-
Chairmen of the Commission and for selecting the talented and dedicated set of
Commissioners with whom we serve.
We have sought to ensure that our review is comprehensive, open and inclusive. The
Commission and its subcommittees have heard from hundreds of individuals and

The purpose of this calculation is to determine the required minimum burnup as a function of initial pressurized water reactor (PWR) assembly enrichment that would permit loading of fuel into the 21 PWR waste package (WP), as provided for in QAP-2-0 Activity Evaluation, Perform Criticality, Thermal, Structural, & Shielding Analyses (Reference 7.1).

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 Centralized Interim Storage Facility (CISF) is designed as a temporary, above-ground away-from-reactor spent fuel storage installation for up to 40,000 metric tons of uranium (MTU). The design is non-site-specific but incorporates conservative environmental and design factors (e.g., 360 mph tornado and 0.75 g seismic loading) intended to be capable of bounding subsequent site-specific factors. Spent fuel is received in dual-purpose canister systems and/or casks already approved for transportation and storage by the Nuclear Regulatory Commission (NRC).

NRC initiated a research activity with the Center for Nuclear Waste Regulatory Analyses (CNWRA®) to develop a conceptual test plan for measuring the quantity of residual water remaining in a canister following vacuum drying to the criterion referenced in NUREG–1536 (NRC, 2010). The test plan will be used to help NRC assess options for independently performing an experimental program or to support engagements with industry or the Department of Energy should they undertake a similar effort.

The Monitored Geologic Repository (MGR) Waste Package Operations (WPO) 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 Emico Fermi Atomic Power Plant (Ref. 1). The Fermi fuel has been considered for disposal at the potential Yucca Mountain site.

This analysis is prepared by the Mined Geologic Disposal System (MGDS) Waste Package Development (WPD) department with the objective of providing a comprehensive, conservative estimate of the consequences of the criticality which could possibly occur as the result of commercial spent nuclear fuel emplaced in the underground repository at Yucca Mountain. The consequences of criticality are measured principally in terms of the resulting changes in radionuclide inventory as a function of the power level and duration of the criticality.

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 the transportation, aging and disposal (TAD) canister-based systems.

The first objective of this calculation is the identification of the degraded configurations of the Enhanced Design Alternatives (EDA) II design that have some possibility of criticality and that can occur within 10,000 years of placement in the repository. The next objective is to evaluate the criticality of these configurations and to estimate the probability of occurrence for those configurations that could support criticality.

The purpose of these calculations is to characterize the criticality safety concerns for the storage of Fast Flux Test Facility (FFTF) nuclear fuel in a Department of Energy spent nuclear fuel (DOE SNF) canister in a co-disposal waste package. These results will be used to support the analysis that will be done to demonstrate concept viability related to use in the Monitored Geologic Repository (MGR) environment.