Combined Waste Form Cost Trade Study

Abstract

A new generation of aqueous nuclear fuel reprocessing, now in development under the auspices of the DOE Office of Nuclear Energy (NE), separates fuel into several fractions, thereby partitioning the wastes into groups of common chemistry. This technology advance enables development of waste management strategies that were not conceivable with PUREX reprocessing. Conventional wisdom suggests minimizing high level waste (HLW) volume is desirable, but logical extrapolation of this concept suggests that at some point the cost of reducing volume further will reach a point of diminishing return and may cease to be cost-effective. This report summarizes an evaluation considering groupings of wastes in terms of cost-benefit for the reprocessing system that concludes it is very difficult to justify the costs of HLW treatment facilities for additional specialized waste forms by reducing HLW disposal costs.Internationally, the typical waste form for HLW from the PUREX process is borosilicate glass containing waste elements as oxides. Unfortunately several fission products (primarily the noble metals Ru, Rh, Pd) have limited solubility in glass, yielding relatively low waste loading, producing more glass, and greater disposal costs. Advanced separations allow matching the waste form to waste stream chemistry, enabling the disposal system to achieve more optimum waste loading with improved performance. Metals can be segregated from oxides and each can be stabilized in forms to minimize the HLW volume for repository disposal. Thus, a more efficient waste management system making the most effective use of advanced waste forms and disposal design for each waste is enabled by advanced separations and how the waste streams are combined. This trade-study was designed to juxtapose a combined waste form baseline waste treatment scheme with two options and to evaluate the cost-benefit using available data from the conceptual design studies supported by DOE-NE. The three strategies included: The alloy case, combining all of the metals including undissolved solids (UDS), technetium (Tc), and transition metal fission products (TMFP) in a metallic alloy and the oxides of the alkali/alkaline earth elements primarily cesium, strontium (Cs/Sr), and lanthanides (Ln) in glass minimizes HLW volume. Implementing a waste management strategy using these state-of-the-art combined waste forms and storage to allow radioactive decay and heat dissipation prior to placement in a repository, makes it possible to place up to 10x the HLW equivalent of SNF in the same repository space.All waste management strategies considered with reprocessing significantly reduced HLW costs versus direct disposal of spent nuclear fuel (SNF). However, using generic costs based on preliminary studies for typical waste stabilization facilities and separations modules, this analysis shows that a fourth strategy, resulting in only one waste form with all wastes in glass is the most cost-effective. Sensitivity studies considering weight and heat limits, separations additives, ...

System Losses and Assessment Trade Study

“…Many evaluations in recent years have resulted in estimates of possible waste streams resulting from spent fuel separations (Gombert 2007, Jones 2007a, Jones 2007b, GNEP 2007, Gombert 2008. The amounts and types of possible waste streams vary based on different assumptions made by the authors regarding the spent fuel properties, separations processes, separation efficiencies, waste forms, and assumed waste stream dispositions.…”

Heat Management Strategy Trade Study

“…The Combined Waste Form Cost Trade Study (Gombert 2008b) builds on the IWMS by evaluating the potential decreases in HLW volumes produced from various SNF reprocessing schemes and the costs associated with that decreased HLW volume. With advanced separations being developed, it is now possible to match the waste form to the waste stream.…”

Advanced Reactors and Associated Fuel Cycle Facilities: Safety and Environmental Impacts

“…This system includes the recycling facilities, the waste processing facilities, storage facilities, the waste transportation infrastructure, and the disposal of all classes of waste. Recognizing the variety of considerations involved in developing a waste management system for an advanced nuclear fuel cycle, the GNEP/ AFCI program developed an integrated waste management system (IWMS) as described in Gombert (2008). The IWMS establishes a logical framework for directing waste management and disposition alternatives based on waste radionuclide content, as shown in Fig.…”

“…The volume of each of the reference UREX ϩ1a waste streams that would be generated from the processing of commercial spent nuclear fuel has been estimated and shown in Table 4 from Gombert et al (2008). These waste streams would require management and ultimate disposal.…”

“…As an example, an evaluation was just completed (Gombert et al 2008) regarding the disposition of the transition metal fission products (TMFP). Combining the TMFP with the Cs/Sr/Ln waste stream would allow one step in the UREX ϩ1a process to be eliminated.…”