Active and passive neutron-coincidence counting (NCC) is used routinely for nondestructive assay (NDA) of uranium and plutonium, in many forms. Passive neutron multiplicity counting (PNMC) is used routinely for NDA of plutonium scrap and waste. We’ve developed and extensively tested new electronics that significantly improves precision of double and triple coincidences, and multiplicity assays....

The subsurface migration of Pu may be enhanced by the presence of colloidal forms of Pu. Therefore, complete evaluation of the risk posed by subsurface Pu contamination needs to include a detailed physical/chemical understanding of Pu colloid formation and interactions of Pu colloids with environmentally relevant solid phases. Transmission electron microscopy (TEM) was used to characterize Pu n...

Multiattribute evaluation of alternatives for the disposition of surplus weapons-usable plutonium on the base of fuzzy sets has been made.

Thorium is an element for possible use as nuclear fuel, because of the fertile property of Th-232, which could convert into U-233 after neutron capture and beta decays. However, thorium based fuels have not been successfully implemented, because of the high cost and the higher complexity compared with once-through uranium fuel. Therefore, the focus of this thesis is on thorium for use in tradit...

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