PC-MHR SPENT FUEL - AN IDEAL WASTE FORM FOR PERMANENT DISPOSAL

摘要

Current estimates indicate that disposition of 50 or more metric tons of excess weapons-grade plutonium (WPu) may be required in the U.S. The disposition strategy recommended by General Atomics (GA) is to deeply burn and degrade the WPu as coated particle plutonium oxide fuel in Plutonium Consumption Modular Helium Reactors (PC-MHRs). which are based on established high-temperature, gas-cooled reactor (HTGR) technology. Net revenues would be obtained from the sale of electricity, which is generated using direct-cycle gas turbines with a high-efficiency Brayton cycle. Spent fuel elements discharged from the PC-MHR are ideal waste forms for permanent disposal in a geologic repository. The graphite fuel elements and the ceramic coatings on the fuel particles are as-manufactured engineered barriers that provide excellent near-field containment of radionuclides and minimize reliance on the waste package and surrounding geologic media for long-term containment. Because of the high level of plutonium destruction and degradation achieved by the PC-MHR, the isotopic composition of residual plutonium in spent fuel elements would not be practical for use in nuclear weapons. Dilution of plutonium within the relatively large volume of PC-MHR fuel elements provides excellent resistance to diversion throughout the fuel cycle. This is accomplished without adversely impacting repository land requirements, since repository loading is determined by decay heat load and not by physical volume. Overall disposal costs for PC-MHR spent fuel should be comparable to those for spent fuel from a light water reactor (LWR) used for disposition of WPu, with the added benefit of a superior permanent waste form.