This analysis is prepared by the Mined Geologic Disposal System (MODS) Waste Package Development (WPD) department to provide an evaluation of the criticality potential within a waste package having some or all of its contents degraded by corrosion and removal of neutron absorbers. This analysis is also intended to provide an estimate of the consequences of any internal criticality, particularly in terms of any increase in radionuclide inventory. These consequence estimates will be used as part of the WPD input to the Total System Performance Assessment.

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

There are more than 250 forms of U.S. Department of Energy (DOE)­owned spent nuclear fuel (SNF). Due to the variety of the spent nuclear fuel, the National Spent Nuclear Fuel Program (NSNFP) has designated nine representative fuel groups for disposal criticality analyses based on fuel matrix, primary fissile isotope, and enrichment. For each fuel group, a fuel type that represents the characteristics of all fuels in that group has been selected for detailed analysis.

The objective of this analysis is to characterize a codisposal canister containing MIT or ORR fuel in the Five-Pack defense high level waste (DHLW) waste package (WP) to demonstrate concept viability related to use in the Mined Geologic Disposal System (MGDS) environment for the postclosure time frame. The purpose of this analysis is to investigate the disposal criticality and shielding issues for the DHLW WP and establish DHLW WP and codisposal canister compatibility with the MGDS, and to provide criticality and shielding evaluations for the preliminary DHLW WP design.

The purpose of this calculation is to perform a parametric study to determine the effects of fission product leaching, assembly collapse, and iron oxide loss (Me203) on the reactivity of a waste package (WP) containing mixed oxide (MOX) spent nuclear fuel (SNF). Previous calculations (CRWMS M&O 1998a) have shown that the criticality control features of the WP are adequate to prevent criticality of a flooded WP for all the enrichment/ burnup pairs expected for the MOX SNF.

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

In this study, the long-term geochemical behavior of waste package (WP), containing Pu-ceramic, was modeled. The ceramic under consideration contains Ti, U, Pu, Gd and Hf in a pyrochlore structure; the Gd and Hf stabilize the mineral structure, but are also intended to provide criticality control. The specific study objectives were to determine:
1) the extent to which criticality control material, suggested for this WP design, will remain in the WP after corrosion/dissolution of the initial package configuration (such that it can be effective in preventing criticality), and

At the request of the staff to the Blue Ribbon Commission on America’s Nuclear Future (“BRC”), we have reviewed the following questions:
1. Is there legal authority for DOE or any other entity to undertake to site a repository for “co-mingled” nuclear materials (i.e., civilian and defense spent nuclear fuel (SNF) and high-level radioactive waste (HLW)) at any site other than Yucca Mountain?

The objective of this analysis is to characterize the criticality safety aspects of a degraded Department of Energy spent nuclear fuel (DOESNF) canister containing Masachusetts Institute of Technology (MIT) or Oak Ridge Research (ORR) fuel in the Five Pack defense high level waste (DHLW) waste package to demonstrate concept viability related to use in the Minded Geologic Disposal System (MGDS) environment for the postclosure time frame.

Gentlemen,
In accordance with the charter of the Blue Ribbon Commission on America's Nuclear Future and as the Secretary's designee, I approve your request to establish an ad hoc subcommittee to review and make a recommendation to the Commission regarding the co-mingling of defense and commercial waste.
This letter also serves to appoint Dr. Allison Macfarlane as the chair of the subcommittee and the membership of the subcommittee as identified in your letter to me dated October 31, 2011.

Thep purpose of this calculation is to perform degraded mode criticality evaluations of plutonium disposed in a ceramic waste form and emplaced in a Monitored geologic Repository (MGR). A 5 Defense High-Level Waste (DHLW) Canister Waste Package (WP) design, incorporating the can-in-canister concept for plutonium immobilization is considered in this calculation. Each HLW glass pour canister contains 7 tubes. Each tube contains 4 cans, with 20 ceramic disks (immobilized plutonium) in each.

The purpose of this calculation is to characterize the criticality aspect of the codisposal of TRIGA (Training, Research, Isotopes, General Atomic) reactor spent nuclear fuel (SNF) with Savannah River Site (SRS) high-level waste (HLW). The TRIGA SNF is loaded into a Department of Energy (DOE) standardized SNF canister which is centrally positioned inside five-canister defense SRS HLW waste package (WP). The objective of the calculation is to investigate the criticality issues for the WP containing the five SRS HLW and DOE SNF canisters in various stages of degradation.

This analysis is prepared by the Mined Geologic Disposal System (MGDS) Waste Package Development (WPD) department to provide an evaluation of the criticality potential within a waste package having some or all of its contents degraded by corrosion and removal of neutron absorbers. This analysis is also intended to provide an estimate of the consequences of any internal criticality, particularly in terms of any increase in radionuclide inventory. These consequence estimates will be used as part of the WPD input to the Total System Performance Assessment.

The purpose of this calculation is to perform a parametric study to determine the effects of fission product leaching, assembly collapse, and iron oxide loss on the reactivity of a waste package (WP) containing mixed oxide (MOX) spent nuclear fuel (SNF). Previous calculations (CRWMS M&O 1998a) have shown that the criticality control features of the WP are adequate to prevent criticality of a flooded WP for all the enrichment/burnup pairs expected for the MOX SNF.

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.

The effects of radiation on the corrosion of various metals and alloys, particularly with respect to in-reactor processes, has been discussed by a number of authors (Shoesmith and King 1998, p.2). Shoesmith and King (1998) additionally discuss the effects of radiation of the proposed Monitored Geologic Repository (MGR) Waste Package (WP) materials. Radiation effects on the corrosion of metals and alloys include, among other things, radiolysis of local gaseous and aqueous environments lead to the fixation of nitrogen as NO, NO2, and especially HN03 (Reed and Van Konynenburg 1988, pp.