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Lecture 1: IntroductionNuclear Forensics and the Fuel Cycle
• Readings: § Nuclear Forensics
Analysis: Chapter 1 Introduction
• Class organization§ Outcomes§ Grading
• Introduction§ What is nuclear
forensics• Nuclear material
§ Types of material § Critical masses
• Device development• Forensic goals
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Introduction
• Course objectives§ Understand and comprehend technical aspects
of nuclear forensics§ Highlight role of radiochemistry in nuclear
forensics§ Apply technical aspects to the nuclear fuel
cycle• Course will emphasize the role of nuclear forensics
in the nuclear fuel cycle§ Evaluate available tools§ Assess applications and limitations
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Course overview• Course topics
§ Basics of radiochemistry for nuclear forensics§ Role of applications in nuclear forensics§ Chemistry and physics involved in forensics§ Principles of devices§ Sampling§ Laboratory techniques§ Application of signatures§ Signatures from the fuel cycle
• Textbooks and published literature are used a reading material§ Moody, Hutcheon, Grant: Nuclear Forensic
Analysis• http://radchem.nevada.edu/classes/forfuel/index.htm
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Outcomes
1. Understand, utilize, and apply radiochemistry to nuclear forensics§ Bring chart of nuclide to class§ Fission§ Growth and decay
2. Understand how signatures can arise from applications§ Different aspects of the fuel cycle§ Utilization and treatment of material
3. Understand the basic principles of devices§ Types of devices§ Expected signatures
4. Understand types of signatures available from analysis§ Chronometry§ Isotopics§ Standard
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Outcomes5. Comprehend role of sample collection in
nuclear forensics§ Types of samples available
6. Understand differ laboratory methods for nuclear forensics§ Isotopic analysis§ Microscopy
7. Understand how signatures are used§ Determining source and attribution
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Grading (nominal)• Homework (15 %)
§ Based upon presented information• Two comprehensive quizzes (35% each)
§ Based on topic covered in lecture and homework
• Class participation (15 %) § Be prepared for discussion
• Goal of quizzes is material comprehension• Nature of comprehensive quizzes
§ Take home§ Lead to ideas for proposal
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Outline: LecturesDate Topic
Wednesday 23-Jan No Class
Monday 28-Jan No Class
Wednesday 30-Jan Introduction, Radiochemistry In Nuclear Forensics
Monday 04-Feb Radiochemistry In Nuclear Forensics
Wednesday 06-Feb No Class
Monday 11-Feb Signatures From Applications Of Nuclear Material
Wednesday 13-Feb Signatures From Applications Of Nuclear Material
Monday 18-Feb HOLIDAY Chemistry In Nuclear Forensics
Wednesday 20-Feb Chemistry In Nuclear Forensics
Monday 25-Feb Chemistry In Nuclear Forensics
Wednesday 27-Feb Principles Of Devices
Monday 04-Mar Principles Of Devices
Wednesday 06-Mar Chronometry
Monday 11-Mar Small Sample Techniques
Wednesday 13-Mar Sample Collection And Preparation
Monday 18-Mar Sample Collection And Preparation
Wednesday 20-Mar Inorganic Samples (EXAM)
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Outline: LecturesDate Topic
Monday 01-Apr Inorganic Samples
Wednesday 03-Apr Organic And Other Sample
Monday 08-Apr Laboratory Techniques
Wednesday 10-Apr Laboratory Techniques
Monday 15-Apr Production Estimates, Attribution
Wednesday 17-Apr Attribution
Monday 22-Apr Signatures From Milling And Processing
Wednesday 24-Apr Signatures From Enrichment And Conversion
Monday 29-Apr Signatures From Fuel Production
Wednesday 01-May Signatures From Fuel Burnup
Monday 06-May Separations Signatures
Wednesday 08-May Overview Of Processes For Forensics and Safeguards
Monday 13-May Final Exam
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Introduction• What is nuclear forensics?
§ A number of different views existà Evidence, analysisà Input into attributionà Focus on tools
• Nuclear Materials§ Material in devices
à Fissile isotopes (special nuclear material)* Enriched in 233U or 235U
Ø 235U level can define material (LEU, HEU)
Ø Oralloy 93.5% 235U* Containing any isotopes 238-242Pu
Ø Weapons grade 93 % 239PuØ Reactor grade 8% < 240Pu
Ø MOX 60 % 239Pu, 25 % 240Pu
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Nuclear Material
• Other nuclear material§ 237Np
à high energy neutrons for fissionà Protected material under IAEA
§ 241Am§ 252Cf§ 6Li, 2H, 3H
• Source material§ Th and U
• Identify origin and handling of associated material
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Critical masses
• 1 kg of fissile material releases 17 kt TNT equivalent • Minimum quantity of fissile material for nuclear
explosion is critical mass• Estimate volume of critical mass for 235U and 239Pu
Material Bare, Isolated Sphere (kg) Fully Tampered (Reflected) Sphere (kg)
235U 52 17239Pu (a phase) 10 4239Pu (d phase) 16 6
Civil Pu 13 -233U 15 6
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Plutonium is a unique element in exhibiting six different crystallographic phases at ambient pressure (it has a seventh phase under pressure). In addition, unlike most metals, plutonium contracts on melting. Transformations to different crystal structures occur readily and are accompanied by very large volume changes. By comparison, aluminum’s behavior is predictable and uneventful. It expands monotonically on heating in the solid phase, and it also expands on melting. The dashed lines show that thermal contraction on cooling the liquid (L) phase of plutonium extrapolates to that of the β-phase; the thermal contraction on cooling the ε-phase extrapolates to that of the γ-phase.
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Fissile and fertile material
• Fissile material§ Material that can sustain chain reaction
• Fertile materials§ Source material that can create fissile material§ 232Th, 238U
• Enrichment of U§ Gas, electromagnetic separation
• Related to power production and reactor type§ How can these be different?
à Fast, thermal, CANDU§ 1 GWe burns about 1 ton of fissile material annually
à 200 kg of Pu producedà about 70 t of Pu annually formed in reactor worldwide
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Device development• Manhattan project to Cold War
§ Little Boy, U deviceà Total mass 4100 kgà 84 % enriched 235Uà 1 % of U fissioned, 13 kt yield
§ Fat Man, Pu deviceà 6 kg, 95 % < 239Puà Total mass 4900 kgà 20 % efficient, 21 kt yield
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Device development
• Cold war§ Improved design, fission yield
to 500 ktà Blast influence 125 km2
• http://nuclearweaponarchive.org/Usa/Weapons/Allbombs.html
• Fusion with DT or 6LiD§ Up to 60 Mt yield
• Improved explosive, Ga-Pu alloys• Extensive testing and evaluation• US produced about 100 t 239Pu and
994 t HEU
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Treaties• Control of weapons based on treaties
§ Between declared nuclear power§ Usage of fission for power
• 100 tons surplus 239Pu in each US and Russian inventory• Nuclear smuggling
§ Range of material
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Forensic goals
• Determine attributes of material§ Where produced§ What is it§ Transport route
à Legal and safety issues• Traditional forensics
§ Fingerprints, DNA, pollen• Source and route
§ Source from SNM§ Time since separation§ Relate to nuclear fuel cycle
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Topic review
• Discuss nuclear forensics§ Why does it mean different things to different
groups• What are the different types of nuclear material
§ Types of material § Critical masses§ Production methods and sources
• Device development§ How does this influence forensics
• Define forensic goals
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Study Questions
• What is Special Nuclear Material?• What is a critical mass?
§ Include volume analysis• Define nuclear forensics• What are the goals of nuclear forensics?
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