CHEM 418 Nuclear Chemistry, Winter 2016: 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.

CHEM 418 Nuclear Chemistry, Winter 2016: 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.

CHEM 418 Nuclear Chemistry, Winter 2016: 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, including244Pu and naturally produced 239Pu, are discussed.  Large scale plutonium separations are presented, emphasizing the PUREX (Links to an external site.)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.  

CHEM 418 Nuclear Chemistry, Winter 2016: 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 PDF Quiz for lecture 13 contains a signature box.  This is a new addition to the quizzes.

CHEM 418 Nuclear Chemistry, Winter 2016: 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.

CHEM 418 Nuclear Chemistry, Winter 2016: Lecture 11 Speciation

This lecture covers fundamentals of chemical kinetics and thermodynamics, mainly as a review. The thermodynamic discussion relates to Gibbs free energy and equilibrium constants. Kinetic discussion related to its use in data analysis Emphasis of the lectures is applied to information useful for speciation modeling.  Calculations and models for speciation are discussed. Equilibrium modeling using EXCEL and the program CHESS (Links to an external site.) are presented.

CHEM 418 Nuclear Chemistry Winter 2016 Exam 2

Exam 2

Exam 2 Answers

Assigned 11-Feb-16

1st Due Date: 16-Feb-16

2nd Due Date:  19-Feb-16                                                            

Lecture 6:  Gamma Decay

Lecture 7:  Fission

Lecture 8:  Nuclear Force and Nuclear Structure

Lecture 9:  Nuclear Reactions

Lecture 10:  Radiation Interactions

The first iteration of the exam is due 16-Feb-16.  The answers will be posted on 17-Feb-16.  Any incorrect answers can be resubmitted by 19-Feb-16. Changed answers will be worth 50 % of the original grade.  For the 2nd resubmission the work related to the changes must be shown.  Please post all questions to the blog.

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.  Please use 3 significant digits for your answers.

CHEM 418 Nuclear Chemistry, Winter 2016: Lecture 10 Radiation interactions

This lecture, in 2 parts, covers interaction of radiation with matter and includes fundamental interactions, particle ranges, dosimetry, and hot atom chemistry. Interaction of radiation with matter covers energy loss and reactions with charged particles and photons. The stopping power of charged particles in different material is covered, including calculations on energy loss with thickness. Electron backscattering is introduced with examples on different behavior with varied elements. Discussion on photon interaction includes photoelectric effect, Compton effect, and pair production. Units of dosimetry are described. Dosimetry measurements are discussed and quality factors based on particle mass and charge are introduced. Introductory dose calculations are supplied. Radiation protection regulations and the definition of terms (ALI, DAC) are given. A review of hot atom chemistry is given.

CHEM 418 Nuclear Chemistry, Winter 2016: Lecture 9 Nuclear reactions

The lecture on nuclear reactions is presented in two parts. Nuclear reaction notation is introduced. The role of energetics in nuclear reactions is discussed and evaluated, including Q value, reaction barriers, and threshold energy. Center of mass and laboratory frames are discussed. The different processes involved in the formation of isotopes is provided including photonuclear processes. Reaction energetics, mechanisms and types are described. Nuclear reaction cross sections are described, with a presentation on values and limits given. This includes role of angular momentum in cross section values. The stellar production of elements is presented in terms of nuclear reactions. These provide the basis for understanding the formation of isotopes in stars.