Improved heat transfer from radioactive waste canisters

From joint meeting of the American Nuclear Society and the Atomic lndustrial Forum and Nuclear Energy Exhibition; San Francisco, California, USA (11 Nov 1973). Since the radioisotope content that can be tolerated in a canister full of radioactive waste is limited by the amount of heat which can be dissipated from the waste to the surroundings, the heat transfer characteristics of a simple cylindrical canister containing only nonmetallic radioactive wastes were compared with canisters having the following design or content modifications: annular canisters; internally finned canisters; canisters with multiple cooling ports; intimately mixed metal-waste composites; and alternate layers of metal and heat-generating ceramic wastes. The cost of fabricating, filling, and handling cylindrical, annular, and internally finned containers was compared. It was concluded that each modification would contribute to improved heat transfer from the waste to the surroundings and that annular and finned containers capable of containing large waste quantities would have a cost advantage over simple cylindrical containers, but that this cost advantage would be offset by an increase in operating costs for filling, shipping, and maintaining the integrity of the larger containers. (LCL

Functions of an engineered barrier system for a nuclear waste repository in basalt

Defined in this document are the functions of components selected for an engineered barrier system for a nuclear waste repository in basalt. The definitions provide a focal point for barrier material research and development by delineating the purpose and operative lifetime of each component of the engineered system. A five-component system (comprised of waste form, canister, buffer, overpack, and tailored backfill) is discussed in terms of effective operation throughout the course of repository history, recognizing that the emplacement environment changes with time. While components of the system are mutually supporting, redundancy is provided by subsystems of physical and chemical barriers which act in concert with the geology to provide a formidable barrier to transport of hazardous materials to the biosphere. The operating philosophy of the conceptual engineered barrier system is clarified by examples pertinent to storage in basalt, and a technical approach to barrier design and material selection is proposed. A method for system validation and qualification is also included which considers performance criteria proposed by external agencies in conjunction with site-specific models and risk assessment to define acceptable levels of system performance