Coated Particle Fuels for High‐Temperature Reactors
Authors: Kania Michael J. , Nabielek Heinz , Nickel Hubertus 
Published: May 2015

The article contains sections titled:

Introduction

History ofHTGRsand Coated Particle Fuel Development

HTGRsBuilt and Operated

HTGRsDesigned but Not Built

Modular Reactors (1980sDesign)

Current Modular Reactor Designs

Coated Particle Fuel Development

Development in theUK

Development inGermany

Development in theUS

Recent Directions

Fuel Manufacturing Processes

FuelKernel Manufacture

Powder Metallurgical Process

Sol–Gel Process

Gel‐Precipitation Process forUO2Kernels

Gel‐Precipitation Process forUCOKernels

Fabrication ofPuO2Kernels

Ceramic Coatings by CVD

Pyrolytic Carbon (PyC) Coatings

Silicon Carbide (SiC) Coatings

Fuel Element Manufacture

Spherical Fuel Elements for Pebble‐Bed Cores

Hexagonal‐Block Fuel Elements for Prismatic Cores

HTGRFuel Materials Properties

Properties ofUO2Fuel Kernels

Thermal Properties ofUO2

Mechanical Properties ofUO2

Swelling Rate ofUO2

Properties of Pyrolytic Carbon (PyC) Coatings

Thermal Properties ofPyC

Theoretical Density ofPyC

Mechanical Properties ofPyC

Irradiation‐Induced Dimensional Change ofPyC

Properties of Silicon Carbide (SiC) Coatings

Thermal Properties ofSiC

Mechanical Properties ofSiC

Swelling Rate ofSiC

Fuel Quality Control and Performance Evaluation

Quality Control ofUO2Kernels

Quality Control of Coated Particles

Quality Control of Spherical Fuel Elements

Failure Statistics and Performance Requirements

The Mathematics of Failure Statistics

Statistical Analysis of Fuel Element Manufacture

Statistical Analysis of Irradiation Performance

Statistical Analysis of Accident Condition Performance

Comparison to Performance Requirements

Fuel Performance under Normal Operating Conditions

Irradiation Testing of Modern UO2TRISO‐Coated Particles

Accelerated Irradiations in Material Test Reactors

HFR‐P4 Test

SL‐P1 Test

HFR‐K3 Test

FRJ2‐K13 Test

FRJ2‐K15 Test

FRJ2‐P27 Test

Conduct of the Accelerated Tests

HTRMODUL Proof Tests

HFR‐K5 andHFR‐K6

AVRReal‐Time Irradiation Testing

Performance Assessment for Normal Operating Conditions

Fuel Performance under Accident Conditions

Simulation of Core Heat‐Up after Depressurization under Dry Conditions

Analysis of Accident Simulation Testing

Behavior after Water and Air Ingress

Simulation of Water Ingress

Simulation of Air Ingress

HTGRFission Product Generation and Transport

Fission Product Generation

Fission Product Transport

Equivalent Sphere Model for Gas Release

Recoil Release from Fuel

Kernel Release from Post‐Irradiation Heating Tests

Release of Short‐LivedXeandKrIsotopes

Retention by a Single Coating Layer

Release for a Single Shell

Diffusion Data for Coating Layers

Applicability and Uncertainties of Transport Data

Transport and Release from Fuel Elements in Reactor Tests andHTGRs

Fission Product Chemistry andCOGeneration inUO2

Coated Particle Failure Mechanisms

Pressure‐Induced Failure

Internal Gas Pressure Buildup

Predicting Pressure‐Induced Particle Failure

STRESSModeling

TheRedlich–Kwong Equation for Internal Gas Pressure

Cracking ofPyCCoatings due to Fast Fluence

iPyCFailure

iPyC–SiCInterface Debonding

oPyCFailure

Fast Neutron‐InducedPyCCracking

Kernel Migration (Amoeba Effect)

Kernel Migration inUO2‐Coated Particle Fuel

Kernel Migration in Uranium Carbide Coated‐Particle Fuel

Kernel Migration in Thorium Oxide Coated‐Particle Fuel

Corrosion of theSiCLayer

COAttack ofSiC

Palladium–SiCInteractions

Silver Migration throughSiCLayer

Rare Earth Fission Product Attack

SiCDecomposition

As‐Manufactured Defective Particles

Contamination during Manufacture

Irradiation‐Induced Failures

Summary of Coated Particle Failure Mechanisms