Post-irradiation examination (PIE) is an indispensable step in the selection of new or improved research reactor fuel, and in the characterization and understanding of its in-core behaviour. This publication provides an introduction to PIE techniques. It describes a typical PIE process from intercycle inspections in the reactor pool or channel, to hot cell PIE, which is subdivided into non-destructive and destructive testing techniques with their typical output, advantages and drawbacks, and their applicability to understanding fuel irradiation behaviour. Much of the work presented in this publication originated from the research and development of new low enriched uranium research reactor fuels. Intended readers include research reactor operators, regulators and their technical support organizations, fuel developers and manufacturers, laboratory staff, and policy makers.

• 1. INTRODUCTION
  • 1.1. Background
  • 1.2. Objective
  • 1.3. Scope
  • 1.4. Structure
• 2. RESEARCH REACTORS AND THEIR FUELS
  • 2.1. General properties of research reactor fuels
  • 2.2. Plate type fuels
  • 2.3. Rod and tube type fuels
• 3. GENERAL DESCRIPTION OF RESEARCH REACTOR FUEL PHENOMENA
• 4. PRE-IRRADIATION CHARACTERIZATIONS
  • 4.1. Radiography
    • 4.1.1. Fuel location radiography
    • 4.1.2. Density radiography
  • 4.2. Ultrasonic testing
    • 4.2.1. Debond ultrasonic testing scans
    • 4.2.2. Minclad thickness ultrasonic testing scans
• 5. INFRASTRUCTURE AND APPROACH FOR POST-IRRADIATION EXAMINATIONS
• 6. INTERCYCLE POOLSIDE EXAMINATIONS
  • 6.1. In-canal visual examination
  • 6.2. Thickness and interplate space measurements
    • 6.2.1. Contact probe thickness measurements
    • 6.2.2. Ultrasonic measurements
  • 6.3. Gamma scanning
  • 6.4. Sipping or soaking tests
• 7. NON-DESTRUCTIVE POST-IRRADIATION EXAMINATIONS
  • 7.1. Visual examination
  • 7.2. Thickness, diameter and oxide thickness measurements
  • 7.3. Neutron radiography
    • 7.3.1. Neutron radiography of fuel plates
    • 7.3.2. 3-D tomography
  • 7.4. Gamma scanning
    • 7.4.1. Gross gamma and gamma spectrometry measurements of fuel rods
    • 7.4.2. Gross gamma and gamma spectrometry measurements of fuel plates
  • 7.5. Immersion density on miniplates
• 8. DESTRUCTIVE POST-IRRADIATION EXAMINATION TECHNIQUES AND APPLICATIONS
  • 8.1. Guidelines for sampling and sample preparation
    • 8.1.1. Sample production
    • 8.1.2. Sample preparation
  • 8.2. Optical metallography
    • 8.2.1. Phase distribution
    • 8.2.2. Plate swelling behaviour
    • 8.2.3. Fission gas bubbles
    • 8.2.4. Local oxide layer thickness measurement
    • 8.2.5. Local plate, cladding and fuel meat thickness measurements
    • 8.2.6. Microhardness and toughness
  • 8.3. Scanning electron microscopy
    • 8.3.1. Local oxide thickness layer measurement
    • 8.3.2. Fission gas bubbles
    • 8.3.3. Phase distribution
    • 8.3.4. Electron backscatter diffraction
    • 8.3.5. Scanning electron microscope–focused ion beam (dual beam)
  • 8.4. Electron probe microanalysis
  • 8.5. Transmission electron microscopy
  • 8.6. X ray diffraction
  • 8.7. Radiochemical burnup determination
    • 8.7.1. Sample dissolution, separation and analyses
    • 8.7.2. Burnup calculations
• 9. SPECIALIZED CHARACTERIZATION TECHNIQUES
  • 9.1. Nanoindentation
  • 9.2. Bend test and laser shock for bonding
  • 9.3. Thermophysical measurements
    • 9.3.1. Specific heat capacity
    • 9.3.2. Laser flash thermal diffusivity
    • 9.3.3. Dilatometry
  • 9.4. Secondary ion mass spectrometry
  • 9.5. Neutron diffraction
  • 9.6. Small angle neutron scattering
  • 9.7. Temperature transient tests
    • 9.7.1. Fission gas release studies
    • 9.7.2. Blister testing
  • 9.8. Atom probe tomography
• 10. CONCLUSIONS
• REFERENCES
• ABBREVIATIONS
• CONTRIBUTORS TO DRAFTING AND REVIEW
• STRUCTURE OF THE IAEA NUCLEAR ENERGY SERIES