Plutonium processing powdered

Milling. Both processes involve milling. The milling requirement of PUO2 particulates for the ceramic process is less than 20 pm, which is comparable to the 10 pm nominal requirement for the MOX fuel process. For plutonium oxide, particulate less than about 3 pm (corresponding to an aerodynamic equivalent diameter of 10 pm) are respirable. Thus under similar conditions, the potential inhalation dose associated with a spill accident of plutonium oxide powder for the ceramic process is no worse than that for the MOX fuel process. 

Spill of Pu oxide powder. Spills of plutonium oxide powder by human error or equipment failure are always a safety concern. Examples are dropping a container containing Pu oxide, or leaky seals in the Pu oxide process system. Adequate protection systems to protect against accidental spills or leakage are mandatory. 

When reactor-grade plutonium is left in spent fuel, the large size of the fuel assembhes and the lethal radiation fields make it extremely difficult to divert the material covertly. Once the reactor-grade plutonium is separated in the commercial reprocessing option, however, the radiation barrier is almost eliminated, and in certain steps of the process the plutonium is in powder or Hquid form, which is much more easily diverted than large, bulky fuel... 

The skull metal and oxide are first completely burned to oxide by heating in air to 400-500°C. The plutonium metal spontaneously burns and is collected as a green Pu03 powder. This oxide is recycled back as feed for Direct Oxide Reduction. This process is normally 100% efficient with only a small plutonium residue showing up in items such as clean-up rags. 

The conceivable option of using oxide powder (whether of uranium or plutonium) directly, with no postacquisition processing or fabrication, would seem to be the simplest and most rapid way to make a bomb. However, the amount of material required would be considerably greater than if metal were used. 

The extended radiation time for the domestic fuel increases the quantity of fission products and the higher actinides. Pure plutonium product poses nuclear weapons proliferation risk and is the primary reason reprocessing is not practiced in the United States. The modified PUREX process has been practiced on an industrial scale in Europe and supports the production of mixed uranium-plutonium fuel. Blended UO2 and PUO2 powder is compacted and sinter to form the mixed oxide (MOX) fuel pellets much like the enriched UO2 fuel. Natural and depleted uranium can be used to prepare MOX fuel and is the demonstrated option to recover fuel values from spent fuel. 

PNC developed a co-conversion technology utilizing the microwave heating direct denitration process (MH method) which converts plutonium nitrate and uranyl nitrate solution to MOX powder. Compared with the conventional method, it is a simple process and generates less liquid waste. 

The plutonium inventory monitoring system (PIMS) is a network of 142 He neutron detectors in moderating enclosures, which are installed in a plutonium-powder process area at fixed positions outside of process glove boxes and the ventilation system (Simpson et al. 1998 Parvin 2007 Whitehouse et al. 2004). The collected neutron counts are processed in a matrix approach to image the neutron field of the process area. Any change to the in-process inventory will be detected and can be accounted for on a near real-time basis. The PIMS will also be used to verify the clean out and to measure any residual material. The PIMS is operator-owned equipment used jointly with the inspectorate. Appropriate authentication measures are therefore in place to validate the measurement results. 

Current capabilities on DOE reservations SRS— powder metallurgy processing and extrusion LANL—plutonium alloy casting None... 

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