MODULAR PEBBLE-BED REACTOR PROJECT

6,33
MB

111
stron

4727
ID Massachusetts Institute of Technology

2002
rok

Table of Contents

1.0 Introduction 1

2.0 Gas Reactor Fuel Performance Studies 2

2.1 Studies at the INEEL 2

2.1.1 Stress Model Development and Approach 3

2.1.1.1 Basic Particle Behavior 3

2.1.1.2 Material Properties 3

Creep 4

Shrinkage 4

Weibull Parameters 5

Elastic Properties 6

2.1.1.3 Evaluation of Shrinkage Cracks in the IPyC 6

2.1.1.4 Basic Approach Used in Fuel Performance Model 6

Structural Models 6

Statistical Evaluations 8

2.1.1.5 Cracked Particle Model and Results for NPR Experiments 9

2.1.1.6 Standard Particle Model and Results for EU High-Burnup Case 11

2.1.1.7 Effects of Thermal Cycling 13

2.1.1.8 Effects of Varying Poisson’s Ratio in Creep for the Pyrocarbons 14

2.1.1.9 Calculating Particle Batch Failure Probabilities Using an Integral Formulation 14

2.1.2 Fission Gas Release, CO Production and Fission Product Chemistry 15

2.1.2.1 Fission Gas and CO Release Model 15

2.1.2.2 Fission Product Chemistry Module 17

2.2 Studies at MIT 20

2.2.1 In-Core Environment: Simulation of Core Fueling 21

2.2.2 Chemical Model 21

2.2.3 Mechanical Model Development 21

2.2.3.1 Benchmarking the Stress Analysis Model 21

Simulations of NPR-type and HTTR-type Fuel Particles 23

2.2.3.2 Fuel Failure Probability 28

2.2.4 Conclusions and Future Work 28

References for Section 2 28

3.0 Reactor Physics Research 30

3.1 INEEL Work 30

3.1.1 Introduction 30

3.1.2 Advances in the Development of PEBBED 31

3.1.2.1 PEBBED 2.0 – the FORTRAN Version of PEBBED 31

3.1.2.2 Expanded Isotopics Tracking 31

3.1.2.3 Multigroup Energy Treatment 31

3.1.2.4 Enhancements to the Geometric Modeling Capability 31

3.1.2.5 Ex-Core Radionuclide Decay 32

3.1.2.6 The Matrix Approach to Recirculation Analysis 32

Nuclide Flow in Recirculating Cores 32

3.1.3 Application of PEBBED to the Analysis of Pebble-Bed Reactors 34

3.1.3.1 Evaluation of Peak Neutron Flux and Core Eigenvalue of HTR Modul 200 and Eskom PBMR

34

3.1.3.2 Support of Planning for Testing of Eskom PBMR Fuel in the Advanced Test Reactor 36

3.1.4 Study of the Potential for PBRs to be Diverted for Production of Material for Nuclear

Weapons 39

3.1.4.1 Introduction 39

3.1.4.2 Methodology 39

3.1.4.3 Results 40

3.1.4.4 Conclusions 40

3.1.5 Progress at Georgia Institute of Technology on the Development of a Method to Compute

Diffusion Parameters 41

3.1.6 Analysis of Plutonium Concentration and Isotopics Based on the Reactivity-Limited Burnup of

Pebble-Bed Reactor Fuel Using Various Enrichments 42

3.1.6.1 Introduction 42

3.1.6.2 Modeling Methods 42

3.1.6.3 Reactivity-Limited Burnup 43

3.1.6.4 Plutonium Isotopics 44

3.1.6.5 Conclusions 44

3.1.7 Summary and Outlook 45

3.2 MIT Work 45

3.2.1 Introduction 45

3.2.2 Modeling Considerations 46

3.2.3 HTR-PROTEUS 47

3.2.4 HTR-10 49

3.2.5 ASTRA 50

References for Section 3 53

4.0 Reactor Safety and Thermal Hydraulics Modeling 55

4.1 INEEL Research 55

4.1.1 ATHENA Code Simulation 55

4.1.1.1 ATHENA Model 55

4.1.1.2 Results 59

4.1.1.3 Conclusions 62

4.1.2 Scoping Analyses 62

4.1.3 MELCOR Modeling 62

4.1.3.1 MELCOR Model 62

4.1.3.2 Oxidation Model 64

4.1.3.3 Results 65

4.1.3.4 Conclusions 68

4.2 MIT Research 68

4.2.1 The Loss-of-Coolant Accident with Depressurization 68

4.2.1.1 Introduction 68

4.2.1.2 Description of the Model 68

4.2.1.3 Decay Heat Generation 75

4.2.1.4 Boundary Conditions 76

4.2.1.5 The Calculation and the Sensitivity Analysis 77

4.2.1.6 Conclusions and Recommendations 80

4.2.2 The Air Ingress Accident 82

4.2.2.1 Introduction 82

4.2.2.2 The Physical Process of the Accident 82

4.2.2.3 Main Reactions 83

Important Parameters Governing these Reactions 83

4.2.2.4 The Pressure Drop 84

4.2.2.5 The Model 84

The Main Assumptions 84

4.2.2.6 Calculation Procedures 87

4.2.2.7 Results 87

4.2.2.8 Conclusions and Future Work 92

References for Section 4 93

5.0 Conclusions 94

Fuel Performance Model Development 94

Core Neutronics 94

Safety Analysis 94

Appendix: Air Ingress Analyses on a High Temperature Gas-Cooled Reactor (paper published in

Proceedings of 2001 ASME International Mechanical Engineering Congress and Exposition) 95