The Management of Waste Characteristics by the Use of Waste Selection

PAPER NOT AVAILABLE. ABSTRACT: This paper describes die need for, the benefits from, and the limitations on die use of characteristics-based spent nuclear fuel selection at various key points in the Civilian Radioactive Waste Management System. Waste selection is the process of choosing specific waste items (fuel assemblies or containers) in preference to other waste items widiin an inventory of such items. The need for waste selection is characterized by describing die spectrum of spent fuel physical, radiological and thermal characteristics that must be handled. This spectrum is contrasted to the necessity of designing equipment and facilities to handle a defined, and thereafter fixed maximum waste characteristic, and the resultant operational desire to handle waste whose average characteristics are just below die design limit, in order to maximize the use of both physical and radiological/thermal capacities. The benefits of waste selection are characterized by identifying die degree to which various selection methods can improve upon the performance of die reference selection mediod, oldest fuel first. Selection methods include both simple rule-based and more complex performance-based methods. The measures of performance include the number of cask loadings and the uniformity of heat and integrated heat of waste packages emplaced in the repository. The limitations on the degree of selection control are characterized by the identification of systemwide and individual reactor average characteristics relative to the typical design limits of casks, waste packages and repository emplacements. Odier practical limitations are discussed, including tradeoffs with operational practices that minimize waste handling (such as flow-through at the MRS) and die discontinuous nature of spent fuel characteristics.