Feasibility and Incentives for Burnup Credit in Spent-Fuel Transport Casks

Scale-4 Analysis of Pressurized Water Reactor Critical Configurations: Volume 1-Summary

“…Some of the critical calculations in this study were originally run based on default secondorder (P ) scattering cross sections. This approximation was considered sufficient for reactor 1 calculations because fluxes should remain isotropic through most of the core, except near the periphery, which contributes little to the net value of k . To test this hypothesis, and to verify that eff no numerically induced bias resulted from the use of higher order scattering, calculations were rerun using fourth-order (P ) scattering cross sections.…”

“…Such reliance on the reduced reactivity of spent fuel for criticality control is referred to as $burnup credit.# If burnup credit is applied in the design of a cask for use in the transport of spent light-water-reactor (LWR) fuel to a repository, a significant reduction both in the cost of transport and in the risk to the public can be realized. These benefits caused the U.S. Department of Energy (DOE) to initiate a program 1 to investigate the technical issues associated with burnup credit in spent fuel cask design. These efforts have been led by Sandia National Laboratories (SNL) and carried out as part of the Cask Systems Development Program within the Office of Civilian Radioactive Waste Management.…”

Sensitivity and Parametric Evaluations of Significant Aspects of Burnup Credit for PWR Spent Fuel Packages

“…As an historical aside, early burnup credit studies [1][2][3][4][5][6][7] were often based on 23 or 24 actinides and fission products, while later (and current) calculations will be found to be based on only 22 important actinides and fission products. Originally, 24 important burnup credit nuclides were identified, based on existing and anticipated chemical assay data.…”

“…Since the inception of burnup credit studies at ORNL, a significant number of analyses have been performed to study the effect of various parameters on the calculated value of k " or k eff for spent fuel configurations. [1][2][3][4][5][6][7][8][9] This work has included parametric studies of the effect of factors including burnup, cooling time, initial enrichment, use of an axial burnup profile, and the number of subdivisions necessary to accurately account for this profile, reactor operating history, specific power, assembly design, and the nuclides included in spent fuel modeling. However, this earlier work was performed using a variety of baseline model configurations and different versions of the SCALE code system, and was often directed at specific technical questions.…”

Validation of the scale system for PWR spent fuel isotopic composition analyses

“…Recent applications of calculated isotopic contents for depleted reactor fuel include several criticality safety analyses for investigation of storage or shipment of spent fuel. The ANSI/ANS [2][3][4][5][6] 8.1 criticality safety standard requires validation of the analytical methods used in these spent fuel 7 8 criticality analyses. Although this study focuses on isotopes important for criticality studies, the results should be of sufficient scope to apply to other areas such as radiation shielding and heat transfer as well.…”