Thursday, April 28, 2016

Spring 2016: CHEM 312 Lecture 18 Nuclear Forensics

This lecture covers the utilization of radionuclide properties to determine origin, age, used, and other properties of nuclear material. These isotope properties are defined as signatures of nuclear material, and include concentrations, relative amounts, and ratios. Specific details are provided on forensic signatures related to Pu and actinide isotopics. The signatures arising from reactors, separations, and post-detonation are included. For plutonium production these signatures include reactor power, reactor type, time of irradiation, separation method, and time since separation. The signatures include plutonium isotopic mass ratios, plutonium isotopic activity ratios, and transplutonium isotope ratios. Separation signatures include evaluation of Zr, Tc, Ru, and the lanthanides, with examples using Nd isotopics. Alloys of actinide metals as signatures is also presented.

Spring 2016: CHEM 312 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

Thursday, April 21, 2016

Spring 2016: CHEM 312 Lecture 17 Separations

A number of different separation methods for radionuclides, with an emphasis on actinides, are presented. Solvent extraction, ion exchange, electrochemical, volatility and ionic liquid methods are discussed. The fundamental concepts are provided with specific examples on the nuclear fuel cycle. Ideas and concepts for advanced separations are given. Details are provided for the different separation routes discussed. The PUREX process is described. Examples are given for TRUEX and TALSPEAK separations. Specific examples for actinide separations are provided. Part 4 is a summation lecture on transuranic separations that are drawn from the Np, Pu, Am, and Cm lectures. Part 4 is meant as a review and provides a compilation of separation methods, the bulk can be skipped, but examples of questions are provided at the end of the lecture. 

Tuesday, April 19, 2016

Spring 2016: CHEM 312 Quiz 3

Assigned: 19-Apr-16
1st Answers: 23-Apr-16
2nd Answers: 27-Apr-16

Use lecture notes, textbooks, Chart of the Nuclides, Table of the Isotopes, and web pages. Use the chart of the nuclides as your primary dataset for isotope half-life. Show your work or references on a separate page and save electronically. Submission of the work is not required for the 1st due date. Please use 3 significant digits for your answers. For scientific notation please use X.XXEX (i.e, 1230 as 1.23E3)

Lecture 8: Nuclear Structure and Models
Lecture 9: Nuclear Reactions
Lecture 10: Radiation Interaction
Lecture 11: Speciation
Lecture 12: Uranium Chemistry
Lecture 13: Neptunium Chemistry

Monday, April 11, 2016

Spring 2016: CHEM 312 Lecture 15 Americium and Curium 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.

Tuesday, April 5, 2016

Spring 2016: CHEM 312 Lecture 14 Plutonium Chemistry

This lecture provides basic information on the chemistry of plutonium. 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, emphasizing 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 various nature of plutonium chemistry in the tributylphosphate-nitric acid system and colloids. The non-aqueous chemistry of plutonium is described and related to electronic structure