Weapon plutonium conversion

Aloy, A. S., Kovarskaya, E. N., Koltsova, T. I., Samoylov, S. E Rovny, S. I. Medvedev, G. M. 2002. Immobilization of Am-241 formed under plutonium metal conversion into monazite-type ceramic. In Lardine, L. J. Borisov, G. B. (eds) Review of Excess Weapons Plutonium Disposition. LLNL Contract Work in Russia, UCRL-ID-149341, 141-145. 

The ongoing joint United States/Russian Federation project to develop and construct a version of the GT-MHR to consume surplus weapons plutonium is an important element of commercial GT-MHR development. The major systems, structures and components of the GT-MHR, including the power conversion system, reactor vessel and internals, and reactor building, can be developed and demonstrated through this project. The primary alterations to the plutonium consumption design are expected to be in the reactor core and possibly the reactor cavity cooling system, with the remainder of the commercial GT-MHR drawing directly from the plutonium consumption version. 

The capability to use RADTRAN was subsequently demonstrated through a comparative risk assessment of two hypothetical versions of a campaign to transform the surplus weapons-grade plutonium currently stored at the DOE s Pantex site (near Amarillo) into mixed-oxide fuel, and ship it to a reactor site for utilization. In one of these hypothetical campaigns, the conversion and fabrication were performed on-site at Pantex, whereas in the second version the plutonium pits were shipped from Pantex to an intermediate site for conversion into oxide form and fabrication into fuel. The interested reader is referred to [14] for the results of this assessment. 

Most studies and reviews of nuclear weapons and their effects have focused almost exclusively on what would happen if they were used. Notably, though, this represents only one phase in the life cycle of nuclear weapons, which includes uranium mining, milling, conversion, and enrichment plutonium production and separation nuclear fuel transport other raw material production and weapon assembly, transport, storage, testing, maintenance and refurbishment, use, and disassembly and disposal, including recycling or disposal of aU component parts [7]. 

A question has been raised as to whether the uranium oxides that may be produced during the conversion process (e.g., UO3 and UsOs) are of suitable composition and purity to be used for reactor fuel fabrication. The purpose of this report is to explore the technical feasibility for using these natural uranium compounds as reactor fuel for the production of weapons-grade plutonium. This report and the analyses discussed focus primarily on the physics issues and address whether there are limitations is using these oxides as fuel. 

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