Dear Tim:
As we work to complete our final recommendations to the Secretary by January 29, 2012,
we have determined that our efforts would be aided by the formation of an ad hoc
subcommittee to investigate the issue of co‐mingling of defense and commercial wastes.
Specifically, the ad hoc subcommittee would review and make a recommendation to the
Commission on the issue of whether the 1985 Presidential decision to co‐mingle defense
and commercial wastes for disposal should be revisited in light of changes that have

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

The Range of Neutronic Parameters for Repository Criticality Analyses technical report contains a summary of the benchmark criticality analyses (including the laboratory critical experiment [LCEs] and the commercial reactor criticals [CRCs]) used to support the validation of the criticality evaluation methods. This report also documents the development of the Critical Limits (CLs) for the repository criticality analyses.

The objective of this calculation is to perform additional degraded mode criticality evaluations of the Department of Energy's (DOE) Fast Flux Test Facility (FFTF) Spent Nuclear Fuel (SNF) codisposed in a 5-Defense High-Level Waste (5-DHLW) Waste Package (WP). The scope of this calculation is limited to the most reactive degraded configurations of the codisposal WP with an almost intact Ident-69 container (breached and flooded but otherwise non-degraded) containing intact FFTF SNF pins.

This report is in response to the directive of the House Appropriations Subcommittee for Energy and Water
Development that the Department of Energy (DOE) update a 1984 report of alternative means of financing and
managing (AMFM) the Office of Civilian Radioactive Waste Management (OCRWM) in the DOE. The
President’s FY 2002 budget also stated: “DOE will submit to Congress an updated report regarding alternative
approaches to finance and manage the program by June 30, 2001[.] DOE will identify in this report models of

Reference concepts for geologic disposal of used nuclear fuel and high-level radioactive waste in
the U.S. are developed, including geologic settings and engineered barriers. Repository thermal
analysis is demonstrated for a range of waste types from projected future, advanced nuclear fuel
cycles. The results show significant differences among geologic media considered (clay/shale,
crystalline rock, salt), and also that waste package size and waste loading must be limited to meet
targeted maximum temperature values.