We present a new time-based cross-section parameterization scheme that allows for a more accurate global depletion analysis than current methodologies without requiring major modifications to existing codes. The new cross-section parameterization scheme makes use of few-group macroscopic cross sections calculated as a function of time at several different power levels. These cross sections are block ordered by time rather than exposure to allow for the explicit representation of instantaneous control, i.e., soluble boron concentration, and thus accurate isotopic history, within the base cross-section library. The scheme is applied to a global depletion analysis of the Slightly Enriched Spectral-Shift Reactor, an advanced converter reactor based on a pressurized water reactor design, using the CPM-2 assembly-level collision probability code and the UM2DB two-dimensional diffusion code. The depletion calculation establishes the feasibility and potential advantages of the proposed cross-section parameterization methodology and shows that through a judicious choice of spectral shift control rod withdrawal strategies, it is possible to substantially increase fuel resource utilization via the spectral shift effect while maintaining acceptable power peaking factors.
