Nuclear safeguards considerations for pebble bed reactors (PBRs)

摘要: Abstract Recent reports by the Department of Energy National Laboratories have discussed safeguards considerations for low enriched uranium (LEU)-fueled pebble bed reactors (PBRs) and need bulk accountancy plutonium in “used fuel.” These fail to account degree dilution graphitized-carbon pebbles that is sufficient meet International Atomic Agency (IAEA) “provisional” guidelines termination on “measured discards.” The thrust this finding not terminate but limit specific stored used fuel. While residual fuel sufficiently diluted IAEA provisional safeguards, estimated quantities minor isotopes 232 U 236 at target burnup ∼90 Gigawatt-days per metric ton (GWD/MT) exceed standard specification limits reprocessed will require extensive blending with either natural or enrichment tails dilute content fall within specification. Hence, PBR less desirable commercial reprocessing reuse than from light water reactors. Also activity a isotopic mixture its A 2 values effective dose if released dispersible form during transportation accident are more limiting equivalent light-water-reactor 55 GWD/MT without accounting presence principal carry-over fission product (technetium, 99 Tc) contamination. Thus, potentially recoverable carries reactivity penalties radiological likely greater those factors impact economics reprocessing, significant consideration technologies coated particle fuels encased graphitized carbon progressed beyond laboratory-scale demonstrations. However, key equipment has been tested past (such as graphite burners electrolytic disintegration/dissolution devices) listed “Trigger List” “Dual Use mandatory export controls. If gross determined fission-product gamma-ray inspection discharged cannot be correlated acceptably predicted pebble, development testing may required detector concepts directly measuring ensure placement spent storage tanks an acceptable measured discard plutonium.