Plutonium Fuel Technology, Part I: Plutonium Fuel Fabrication

The U.S. Atomic Energy Commission is developing general design criteria for plutonium processing and fabrication plants. In the meantime, an Atomic Energy Commission review of proposed sites and design plans for such facilities is required prior to the start of construction. The design of most new plutonium facilities today anticipates a reduction in the maximum permissible personnel radiation exposure from the present 5 rem/yr to 1 rem/yr.Plutonium-uranium mixed-oxide fuels for thermal reactors are most frequently prepared from mechanically blended PuO2 and UO2 powders. Fuel pellets, fabricated by dry powder preparations, cold pressing, sintering, and grinding to size, are encapsulated in Zircaloy tubes, which are then assembled into bundles as required for each reactor. Alternate mixed-oxide fuel fabrication techniques include preparation of coprecipitated UO2-PuO2 powders, binder addition by a wet process, hot pressing, and the use of packed-particle rather than pelletized fuels. Packed-particle fuel materials that have been utilized were prepared by a high energy pneumatic impaction process, a sol-gel process, or by cold pressing and sintering. Such fuel materials are packed in rods by either a vibratory compaction or a swaging process. A quality assurance program is required which covers all planned actions necessary to provide the degree of confidence needed to ensure that the fuels meet or exceed the requirements of design specifications.