This lecture describes the chemistry of actinides and fission products in reactors, primarily focusing on phases formed in nuclear fuel. The fission process is reviewed and fuel burnup discussed. Determining fission product and actinide concentration to assess burnup is introduced. The variation of fission product and actinide concentration with burnup and initial fuel composition is provided. Axial and radial distribution of activity, fission products, and actinides is discussed, highlighting the role of neutron flux and energies on the distribution. Conditions necessary for the formation of separate phases in UO2 are shown for perovskite and metallic phases, emphasizing the role of oxygen in the process. The behavior of fission products can be grouped into 4 areas: volatile species, metallic precipitates, oxide precipitates, and solid solutions.
In the chart about the four classifications of fission product behavior, how is Te classified as each of the four?
ReplyDeleteTe has a range of chemical forms that manifest the different behaviors. These relative amount of Te with the different behavior is influence by chemical conditions.
DeleteThis lecture got me thinking about the distribution of fission products as a function of radius-- it makes sense but I didn't realize it was governed by thermal neutron flux profile.
ReplyDeleteThanks for the comment
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ReplyDeleteDo you know of any fuel reprocessing techniques that look at using how the fission products are distributed throughout the fuel? For instance, if the Pu tends to migrate to the outer edges of the fuel, could you not mechanically "shave off" the Pu shell and simplify your waste stream?
ReplyDeleteI have discussed those in class but no methods have been examined to utilize the in situ fuel chemistry. I am interested in exploring this.
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