Design of an Actinide Burning, Lead or Lead-Bismuth Cooled Reactor that ProducesLow Cost Electricity

摘要

The purpose of this Idaho National Engineering and Environmental Laboratory(INEEL) and Massachusetts Institute of Technology (MIT) University Research Consortium (URC) project is to investigate the suitability of lead or lead-bismuth cooled fast reactors for producing low-cost electricity as well as for actinide burning. The goal is to identify and analyze the key technical issues in core neutronics, materials, thermal-hydraulics, fuels, and economics associated with the development of this reactor concept. Work has been accomplished in four major areas of research: core neutronic design, material compatibility, plant engineering, and coolant activation. In the area of core neutronic design, the reactivity vs. burnup and discharge isotopics of both non-fertile and fertile fuels were evaluated. An innovative core for pure actinide burning that uses streaming, fertile-free fuel assemblies was studied in depth. This particular core exhibits excellent reactivity performance upon coolant voiding, even for voids that occur in the core center, and has a transuranic (TRU) destruction rate that is comparable to the proposed accelerator transmutation of waste (ATW) facility. These studies suggest that a core can be designed to achieve a long life while maintaining safety and minimizing waste. In the area of material compatibility studies, an experimental apparatus for the investigation of the flow-assisted dissolution and precipitation (corrosion) of potential fuel cladding and structural materials has been designed and built at the INEEL. The INEEL forced-convection corrosion cell consists of a small heated vessel with a shroud and gas flow system. The corrosion cell is being used to test steel that is commercially available in the US to temperatures above 650 C. Progress in plant engineering was made for two reactor concepts, one utilizing an indirect cycle with heat exchangers and the other utilizing a direct-contact steam cycle. The evaluation of the indirect cycle designs has investigated the effects of various parameters to increase electric production at full power. For the direct-contact reactor, major issues related to the direct-contact heat transfer rate and entrainment and carryover of liquid lead-bismuth to the turbine have been identified and analyzed. An economic analysis approach was also developed to determine the cost of electricity production in the lead-bismuth reactor. The approach will be formulated into a model and applied to develop scientific cost estimates for the different reactor designs and thus aid in the selection of the most economic option. In the area of lead-bismuth coolant activation, the radiological hazard was evaluated with particular emphasis on the direct-contact reactor. In this system, the lack of a physical barrier between the primary and secondary coolant favors the release of the alpha-emitter Po-210 and its transport throughout the plant. Modeling undertaken on the basis of the scarce information available in the literature confirmed the importance of this issue, as well as the need for experimental work to reduce the uncertainties on the basic characteristics of volatile polonium chemical forms.