Lecture 16: In reactor chemistry

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.

Quiz 4: Am and Cm chemistry, reactors, radiation interaction, detectors

Assigned:  13 July 2014

Due:  18 July 2014

Topics

Lecture 15:  Am and Curium Chemistry Chemistry

Light Water Reactor Fuel

Fast Reactor, Gas Cooled Reactor

Fuel design considerations

History of nuclear fuel reprocessing

TRIGA Reactors

Radiation interactions and dosimetry

Detectors

Use lecture notes, textbooks, Chart of the Nuclides, Table of the Isotopes, and web pages.   Show your work or reference.  If you use a spreadsheet please include what equations you used to solve the problem.

Lecture 15: Am and Cm chemistry

This lecture introduces the chemistry of americium and curium. Both elements are discussed due to their similar chemical behavior, particularly in separations. However, important differences in their chemistry are highlighted. For americium pentavalent and hexavalent species are achievable. For curium, its unique fluorescence properties are highlighted. The nuclear properties of americium and curium isotopes are provided. Isotope production focus on those formed from multiple neutron capture. These isotopes, ²⁴¹Am, ²⁴³Am, ²⁴⁴Cm and ²⁴⁸Cm, are used to explore americium and curium chemistry. The basic solution chemistry is described, along with implications for fuel cycle separations. Methods for the separation of americium and curium are provided, including solvent extractions, anion exchange, precipitation, and molten salt techniques. Synthesis and characterization of americium and curium metals, alloys, and compounds are provided, with emphasis placed on those compounds of importance to the nuclear fuel cycle. The non-aqueous and coordination chemistry of these elements are introduced. The limited available data offers an avenue for novel explorations and future research directions. 

Lecture 14: Plutonium Chemistry

This lecture provides basic information on the chemistry of plutonium in three parts. Discussion on the nuclear properties of ²³⁸Pu and ²³⁹Pu are included. Environmental concentrations of plutonium, including ²⁴⁴Pu and naturally produced ²³⁹Pu, are discussed. Large scale plutonium separations are presented, including the PUREX process. The use of volatility and ion exchange as plutonium separation techniques are also given. The synthesis and properties are metallic plutonium are described in detail. An review of metal preparation methods are provided, including the plutonium-gallium phase diagram. The physical properties of plutonium metal are given and discussed. The solution chemistry of plutonium is depicted though coordination and spectroscopy as a function of oxidation state. Examples are provided on the various nature of plutonium chemistry in the solution phase, as colloids, and solid phase. The non-aqueous chemistry of plutonium is described and related to electronic structure.