Table Of ContentLIQUID BONDED LIGHTWATER REACTOR FUEL:
ENHANCED LIGHT WATER REACTOR SAFETY AND PERFORMANCE
By
RICHARD FREDERICK WRIGHT
A DISSERTATION PRESENTEDTOTHE GRADUATE SCHOOL
OFTHE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OFTHE REQUIREMENTS FORTHE DEGREE OF
DOCTOR OF PHILOSOPHY
UNIVERSITY OF FLORIDA
1994
LD
1780
I99i
iiilgi
ACKNOWLEDGEMENTS
TheauthorwishestoexpresshisgratitudetoProfessorJames S.Tuienkofor
hisvision, patience, guidance, enthusiasm, and breadth ofknowledgeofnuclear
fuel design. Without his support, thisworkwould not have been possible.
am also indebted to Dr. Richard G. Conneil, Professor Emeritus Glen J.
I
Schoessow, Thad M. Adams, and Mark Dubecky whose work on this project
parallels myown, andwhohave provided contributionstothiswork. Iwould like
tothankmycommitteemembers; Drs. D.E. Hintenlang, E.T. Dugan, G.R. Dalton,
and F.E. Dunnamfortheirhelpandguidance. AlsoKathyPhillipsforallherhelp.
I would like to acknowledge Dr. Odelli Osserof EPRI and Dennis O'Shay of
Florida Power Corp. fortheir help in obtaining the ESCORE computer program,
and the U.S. DepartmentofEnergyforfunding this research.
would alsoliketothankDr. FrederickJ. Moody, Dr. J. Edward Schmidt, and
I
RobertA. Markley for being friends and mentors, and for helping me to put my
education, careerand life intothe proper perspective.
Iwould liketogivespecialthankstomywife, Denise, and mychildren, Laura
and Rick, and Jim and Betty Hartfortheir love and support. Mostofall I would
liketothank my parents, especially myfather, whowas my inspiration.
TABLE OF CONTENTS
ACKNOWLEDGEMENTS
ii
LISTOFTABLES
vi
LISTOF FIGURES
vii
ABSTRACT x
CHAPTERS
BACKGROUND
1 1
LightWater ReactorFuelTemperatures and Limits 1
Sodium Bonded Metal Fuel Technology 3
Liquid Bonding in LWR Fuel 4
Potential Benefits 4
Disadvantages 5
2 TECHNICAL FEASIBILITY 8
Choice of Bonding Liquid 8
Temperature Range Criteria 9
Nuclear Interaction 10
Material Compatibility 16
Fuel Rod Characteristics 21
BestCandidates 25
Thermal Considerations 26
Steady-state Fuel Temperatures 27
Transient Performance 28
Thermal/Mechanical Limits and Design Criteria 29
Fuel Rod Failure 31
SevereAccidentAnalysis 33
Manufacturing 35
Resultsofthe LBLWR Feasibility Study 37
3 MATERIAL COMPATIBILITYTESTING 39
Discussion ofLiquid Metal Corrosion 40
Experimental Assessment of
Bonding Liquid/Cladding Compatibility 45
Matenals Used in Experimental Samples 45
Sample Preparation 47
Test Matrix 49
Metallographic Preparation ofthe Test Specimens 51
Measurement ofthe Loss ofTube Wall Thickness 52
Transition Layers at the Liquid Metal/Solid
Interface 52
Liquid Metal Attack 53
Results of Material Compatibility Experiments 53
Tube Wall Loss 54
Evaluation of Reaction Layers 64
Liquid Metal Compatibility with UOg 69
Additional Expenmental Studies 72
Fission Gas Flow Through Liquid Metal 72
Liquid Metal-Coolant Interaction 72
Summary of Experimental Studies 72
4 LIQUID METALWETTING IN ANNULAR GAPS 74
Experimental Studies 75
Analytical Predictions of Gas Blanketing dueto Eccentricity .... 75
Results and Conclusions 76
5 LIQUID BONDED FUEL ROD THERMAL ANALYSIS 80
Steady-state Fuel Temperatures 80
Transient Performance 85
Loss ofCoolantAccident 85
Transient Overpower 89
Detailed Two-dimensional Fuel Rod Model 93
6 FUEL ROD THERMAL/MECHANICAL PERFORMANCE ANALYSIS 96
Background 96
ESCORE: Fuel RodThermal/Mechanical Performance Code ... 98
ESBOND: LBLWR Fuel Rod Analysis Code 99
Installation on the Unix Platform 100
ESBOND Gap Conductance Model 102
Liquid Bond Displacement 104
ESBOND LBLWR Fuel Performance Calculations 107
ESBOND Analysis ofthe PWR Fuel Rod 108
ESBOND Analysis ofthe BWR Fuel Rod 120
ESBOND LBLWR Fuel Analysis - Conclusions 130
7 IMPROVED DESIGNS TO ENHANCE LWR FUEL SAFETY 131
Three-Dimensional HeatTransfer Model 132
Optimized LBLWR Fuel Design - Conclusions 140
8 CONCLUSIONS AND RECOMMENDATIONS 144
Experimental Results 146
Analytical Fuel Performance Results 147
PWR Fuel Rod 149
BWR Fuel Rod 150
Recommendations 151
APPENDIX ESBOND LBLWR FUEL PERFORMANCE CODE
SUBROUTINES 153
REFERENCES 203
BIOGRAPHICAL SKETCH 206
LIST OF TABLES
Table page
2-1 Melting and boiling temperatures forcandidate liquids 11
2-2 Thermal neutron absorption cross sectionsfor
liquid metals 13
2-3 Fuel rod parameters for PWR and BWR fuel 22
3-1 ASTM B350 Chemical Composition for
ReactorGradeZircaloy-4 46
3-2 Chemical Composition of Lead-Bismuth Eutectic 46
3-3 Chemical Composition ofthe Tin Stock 48
3-4 Chemical Composition ofthe Lead Stock 48
7-1 Maximum fuel temperaturesforLBLWR pellet designs 135
LISTOF FIGURES
Figure page
2-1 Dopplercoefficient vs. effectivefuel temperature at BOL 15
2-2 Binaryalloy phase diagrams forzirconium-bismuth 18
2-3 Binary alloy phase diagramsforzirconium-lead 19
2-4 Binary alloy phase diagramsforzirconium-tin 20
2-5 Uranium dioxidethermal conductivityvs. temperature 24
3-1 Barnstead-Thermolyne furnaces fortesting samples 50
3-2 Loss ofwall thickness, lead-bismuth samplestested at
1215°Ffor24 hours 55
3-3 Loss ofwall thickness, lead-bismuth samplestested at
1382°Ffor24 hours 56
3-4 Loss ofwall thickness, lead-bismuth samplestested at
1517°Ffor24 hours 57
3-5 Loss ofwallthickness, lead-bismuth-tin samplestested at
1215°Ffor24 hours 58
3-6 Loss ofwall thickness, lead-bismuth-tin samplestested at
1382°Ffor24 hours 59
3-7 Loss ofwall thickness, lead-bismuth-tin samplestested at
1517°Ffor24 hours 60
3-8 Loss ofwall thickness, lead-bismuth samplestested at
750°Ffor 1000 hours 61
3-9 Loss ofwall thickness, lead-bismuth-tin samplestested at
750°Ffor3500 hours 62
VII
3-10 Photomicrograph of reaction layer, lead-bismuth sample,
750T for 1000 hours 65
3-11 Photomicrograph of reaction layer, lead-bismuth-tin sample,
750T for 1000 hours 66
3-12 Electron beam microprobe reaction layeranalysis
lead-bismuth sample 67
3-13 Electron beam microprobe reaction layeranalysis
lead-bismuth-tin sample 68
3-14 Optical photomicrograph and electron beam microprobe
results of lead-bismuth-tin samplewith UOj pellets at
1500°F for24 hours 70
4-1 TRUMP computermodel foreccentric rod study 77
4-2 Eccentric rod study - with and without gas blanketing 78
5-1 Fuel temperature profilevs. gapconductance (6 kW/ft) 82
5-2 Fuel temperature profile vs. gap conductance (13 kW/ft) 83
5-3 Transient responseto a simulated LOCA 88
5-4 Zirconium-water reaction rate constantvs. cladtemperature .... 90
5-5 LBLWRfuel responseto 15%transient overpower 92
5-6 Cosine axial powershape 94
6-1 Program logicflow diagram for ESCORE 101
6-2 Rod internal pressurevs. timeforunmodified PWR
fuel rod 109
6-3 Westinghouse 15x15 LBLWRfuel - rod dimensions 111
6-4 Westinghouse 15x15 LBLWRfuel - average gap conductance . . 112
6-5 Westinghouse 15x15 LBLWRfuel - fuel temperatures 114
6-6 Westinghouse 15x15 LBLWRfuel - rod internal pressure 115
1
6-7 Westinghouse 15x15 LBLWR fuel - fission gas release 117
6-8 Westinghouse 15x15 LBLWR fuel - clad strain at EOL 119
6-9 BWR 8x8 LBLWR fuel - rod dimensions 121
6-10 BWR 8x8 LBLWR fuel - average gap conductance 123
6-1 BWR 8x8 LBLWR fuel - fuel temperatures 124
6-12 BWR 8x8 LBLWR fuel - rod internal pressure 126
6-13 BWR 8x8 LBLWR fuel - fission gas release 127
6-14 BWR 8x8 LBLWR fuel - clad strain at EOL 128
7-1 Proposed LBLWRfuel pelletdesign foroptimized performance . . 133
7-2 Temperature contours, solid pellet, gas bonded 136
7-3 Temperature contours, solid pellet, liquid bonded 137
7-4 Temperaturecontours, annularpellet, gas bonded 138
7-5 Temperature contours, annularpellet, liquid bonded 139
7-6 Temperaturecontours, annular, grooved pellet, gas bonded .... 141
7-7 Temperaturecontours, annular, grooved pellet,
liquid bonded 142
