Thursday, April 20, 2017

Spring 2017 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 1 is 40 minutes, part 2 is 40 minutes, part 3 is 24 minutes, and part 4 is 30 minutes.

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 and should be reviewed.

The lecture is assigned 20 April 17 and due 30 April 17.

Monday, April 17, 2017

Spring 2017 CHEM 312: Lecture 16 Nuclear Reactors and in-reactor chemistry

This lecture provides an overview of nuclear reactors and describes the chemistry of actinides and fission products in reactors. A broad overview of nuclear reactors is provided. The essential components of a reactor, fuel, cladding, coolant, and moderators, are described. Characteristics of reactor materials and nuclear fuels are given. A summary of reactor types, generally classified on coolant properties, is provided. The chemistry of nuclear fuel is provided, with an emphasis placed on understanding the 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 UO2are 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. The lecture is in two parts. Part 1 is length is 36 minutes, part 2 is 32 minutes.  The lecture is assigned 18-Apr-17 and due 23-Apr-17.

Sunday, April 2, 2017

Spring 2017 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. The lecture is in 2 parts; part 1 is 29 minutes and part 2 is 26 minutes.  The lecture is assigned 4-Apr-17 and due 17-Apr-17.

Tuesday, March 28, 2017

Spring 2017 CHEM 312: Exam 3

Assigned: 28-March-2017
1st Answers: 2-Apr-2017
2nd Answers: 5-Apr-2017

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, March 27, 2017

Spring 2017 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. The lecture is in 3 parts; part 1 is 38 minutes, part 2 is 40 minutes, and part 3 is 31 minutes.

Assigned: 28-March-17
Due 4-April-17

Spring 2017 CHEM 312: Lecture 13 Neptunium Chemistry

Neptunium chemistry is covered in this lecture. Nuclear properties and synthesis of neptunium are described, with emphasis placed on the isotopes 235-239Np. The synthesis and properties of neptunium metal, alloys, and intermetallic compounds are introduced. The lecture describes neptunium compound synthesis, with resulting thermodynamic and structural properties provided. Neptunium organometallic and coordination compounds are also presented. Information on neptunium solution speciation, redox, and spectroscopy is given, with trends based on oxidation state examined. A presentation of analytical methods useful in neptunium chemistry, including Mössbauer spectroscopy, concludes the lecture. Comparisons are made with uranium chemistry to provide trends in the actinides. The lecture length is 26 minutes.  The lecture is assigned 27-Mar-17 and due 1-April-17.

Friday, March 17, 2017

Spring 2017 CHEM 312: Lecture 12 Uranium Chemistry

Uranium chemistry is covered in this lecture with an emphasis on separations and synthesis for the nuclear fuel cycle. The solution chemistry of uranium is explored, focusing on uranyl. The molecular orbital of uranium is described. Separation of uranium by solvent extraction and ion exchange is presented. The enrichment of uranium from the uranium hexafluoride species is discussed, including diffusion, centrifuge, and laser methods. Oxide species of uranium are presented. Due to its potential as a nuclear fuel, the synthesis and properties of uranium metal and alloys are described in detail. With three different phase, the uranium metal exhibits more complex electronic behavior than the metals of the lighter actinides, a trend that continues to plutonium metal. The lecture is in two parts; part 1 is 50 minutes and part 2 is 30 minutes.  The lecture is assigned 16-Mar-17 and is due 26-Mar-17.