Abstract ........................................................ 1
Introduction .................................................... 2
Preservation Within the Unsaturated Zone ........................ 7
Natural Caves and Rock Shelters .............................. 9
Manmade Openings ............................................ 14
Dryness and Preservation .................................... 18
Evaluation of Analogues for Preservation in the
Unsaturated Zone ............................................ 18
Repository Drift Stability Analogues ........................... 19
Repository Design Selection and Relation to Applicable
Analogues ................................................... 19
Drift-Stability Analogues ................................... 22
Stability of Natural Underground Openings ................ 23
Stability of Manmade Underground Openings ................ 28
Response of Caves to Seismicity .......................... 35
Response of Manmade Underground Openings to Seismicity ... 38
Underground Openings Affected by Temperature ............. 41
Summary of Drift Stability Analogues ........................ 41
Analogues for the Engineered Barrier System .................... 41
Waste-Form Degradation ...................................... 42
Overview of Conceptual Basis of Waste-Form Degradation ... 42
Spent-Fuel Dissolution in an Oxidizing Environment ....... 43
Analogue Studies Related to Waste-Form Dissolution
Rates .................................................... 45
Analogue Studies Related to Immobilization by Secondary
Minerals ................................................. 47
Radiolysis .................................................. 49
Criticality ................................................. 50
Nuclear Waste Glass Analogues ............................... 51
Summary of Waste-Form Analogues ............................. 53
Engineered Barrier System Design ............................ 54
Waste-Package Degradation Analogues ......................... 60
Natural Analogue Studies of Corrosion .................... 61
Passive Film Formation ................................ 63
Naturally Occurring Metals as Natural Analogues ....... 63
Summary of Waste-Package Degradation Analogues ........... 65
Analogues for Other Engineered Barrier System Components
and Their Effect on Radionuclide Transport .................. 65
Analogues for the Titanium Drip Shield ................... 68
Analogues for the Invert Ballast ......................... 68
Natural Analogues for Development of Alkaline Plumes from
Cement ...................................................... 69
Natural Analogues for Colloidal Transport of Radionuclides
in the Near Field ........................................... 70
Summary of Analogues to Engineered Barrier System
Materials and Processes ..................................... 71
Seepage Analogues .............................................. 71
Seepage Characteristics of Caves ............................ 72
Seepage Characteristics of Underground Openings ............. 74
Summary of Analogues for Seepage ............................ 78
Unsaturated-Zone Flow and Transport Analogues .................. 79
Yucca Mountain Conceptual Unsaturated-Zone Flow and
Transport Models ............................................ 79
Unsaturated-Zone Transport Studies .......................... 80
Limited Fracture/Matrix Interaction at Rainier Mesa,
Nevada ................................................... 80
The Subsurface Disposal Area at the Idaho National
Laboratory as a Potential Analogue for Radionuclide
Transport at Yucca Mountain .............................. 81
Geologic and Hydrologic Setting ....................... 81
Modeling the Large-Scale Aquifer Pumping and
Infiltration Test at the Idaho National Laboratory .... 81
The Subsurface Disposal Area Transport Modeling
Study ................................................. 82
Discussion of the Subsurface Disposal Area Modeling
Study ................................................. 95
Radionuclide Flow and Transport Studies at Nopal I,
Pena Blanca, Chihuahua, Mexico ........................... 96
Background ............................................ 96
Early Characterization of Radionuclide Transport
Using Uranium-Series Disequilibria .................... 98
Seasonal Variability at Nopal 1 ...................... 107
Continued Uranium-Series Analyses .................... 108
Conceptual Model of Transport ........................ 113
Conclusions of Pena Blanca Studies ................... 113
Uranium Deposits in Northwestern Nevada/Southeastern
Oregon .................................................. 114
Akrotiri, Santorini ..................................... 114
Koongarra Uranium Deposit, Alligator Rivers, Northern
Territory, Australia .................................... 115
Busted Butte, Nevada, Tracer Test ....................... 116
Evidence for Colloidal Transport in the Unsaturated
Zone .................................................... 116
Conclusions of Unsaturated-Flow and Transport Analogues .... 117
Coupled Processes Analogues ................................... 118
Introduction ............................................... 118
Yellowstone as a Natural Analogue for Thermal-Hydrologic-
Chemical Processes ......................................... 119
Hydrothermal Sealing .................................... 119
Comparison with Yucca Mountain .......................... 121
Other Examples of Fossil Hydrothermal Systems .............. 122
Yucca Mountain as a Self-Analogue ....................... 122
Paiute Ridge, Banco Bonito, and Grants Ridge ............ 123
Comparison with Yucca Mountain .......................... 124
Numerical Tools ............................................ 124
Summary of Coupled Processes Analogues ..................... 125
Analogues to Saturated-Zone Transport ......................... 127
Conceptual Model of Saturated-Zone Flow and Transport ...... 127
Performance Assessment Insights from Poços de Caldas,
Brazil ..................................................... 128
Uranium Retardation under Oxidizing Conditions at Coles
Hill, Virginia ............................................. 129
Matrix Diffusion Analogues: El Berrocal in Spain,
Palmottu in Finland, and Others ............................ 129
Uranium Retention Under Variable Redox Conditions:
Bangombé in Gabon, and Olden Granite in Sweden ............. 132
Retention of Uranium Along a Fault: Tono Mine, Japan ....... 134
Colloidal Transport in the Saturated Zone .................. 136
Anthropogenic Analogues of Saturated-Zone Flow and
Transport .................................................. 137
Saturated-Zone Transport at Uranium Mill Tailings
Sites ................................................... 137
Gunnison, Colorado, UMTRA Site ....................... 138
New Rifle UMTRA Site, Rifle, Colorado ................ 138
Summary and Conclusions of the UMTRA Study ........... 145
Saturated-Zone Transport at the Idaho National
Laboratory .............................................. 145
Saturated-Zone Transport at the Nevada Test Site ........ 146
Summary of Saturated-Zone Analogues ........................ 147
Applications and Conclusions .................................. 147
Performance Assessment Applications of Analogues in
Geologic Disposal Programs Worldwide ....................... 149
Yucca Mountain Project Incorporation of Natural
Analogues .................................................. 150
Yucca Mountain Project Identified Needs and Applications
from this Report ........................................... 151
Remaining Areas for Increased Process Understanding
through Analogue Studies ................................... 151
Acknowledgments ............................................... 152
References .................................................... 156
Appendix—Known Caves with Assigned Ages and the Methods of
Age Determination ............................................. 185
Figures
1. Location map of Yucca Mountain site in Nevada ............ 5
2. Generalized stratigraphic cross section across Yucca
Mountain, Nevada ......................................... 6
3. Drawing showing the combination of natural and
engineered features that are expected to contribute to
waste isolation .......................................... 7
4-17. Photographs showing:
4. 9,000-year-old flutes carved from the leg bone of
a red-crowned crane .................................. 8
5. Silver and iron artifacts recovered from Pompeii,
Italy, displayed at the Naples Museum ................ 9
6. Materials preserved by burial in volcanic ash at
Herculaneum in A.D. 79 .............................. 10
7. Packrat midden from the Sheep Range in Nevada ....... 11
8. Split-twig figurines made of willow ................. 11
9. Fox-skin quiver, atlatl, and darts from Cowbone
Cave, northern Nevada ............................... 12
10. Footwear recovered from Arnold Research Cave in
Missouri ............................................ 12
11. Painted rhinoceroses, horses, and oryxes from
ChauvetCave, France ................................. 12
12. The funeral barque of the Pharaoh Cheops (Khufu) .... 14
13. The painted interiors of many Egyptian tombs show
no signs of damage except vandalism ................. 15
14. Frescoes from Etruscan tombs of Tarquinia, Italy .... 16
15. Columns and ceiling of Ajanta Cave #10, India,
painted on a mud plaster in the second century
B.C., showing some spallation in lower part of
photograph .......................................... 17
16. Fresco from Karanlik church, Goreme, Turkey ......... 18
17. Tomb of Tanwetamani in El Kurru, Sudan, showing
the destruction of plaster and painting to the
level of a mudflow, which partly filled the tomb
after it was left open by grave robbers ............. 19
18. Variables affecting thermal performance of
a repository ............................................ 21
19. Diagrams illustrating the drift shadow concept under
[A) diffusion-dominated, and (B) advection-dominated
conditions .............................................. 22
20. Diagram showing configuration of an intact drift and
a drift that has collapsed over a long timeframe ........ 23
21-28. Photographs showing:
21. Fairyland in Carlsbad Caverns, New Mexico ........... 25
22. (A) Lava tube in Undara, Australia. (B) Nahuku
lava tube and lava stalactites from Hawaii .......... 25
23. Tubo Volcánico Corona, Lanzarote, Canary Islands,
with a man shown for scale and a schematic cross
sections of the lava tube ........................... 26
24. Megabreccia in Titus Canyon, in the northeast
corner of Death Valley National Park, California .... 27
25. The Neolithic flint mine at Krzemionki Opatowskie,
Poland .............................................. 28
26. The Nubian Limestone that hosts the tombs in the
Valley of the Kings in Egypt ........................ 29
27. (A) Mined-out cavern in the Laurion mines, Greece,
and (В) а temple at Wadi Sikait, Egypt, which was
excavated in a talc schist during the first
century B.C ......................................... 30
28. (A) The tunnel of Eupalinus, Greece, and [B) the
tunnel of Hezekiah, Israel .......................... 30
29. Location map for the Greek and Roman tunnels discussed
in the text and for the Italian caves studied for
paleoseismicity ......................................... 31
30. Photographs showing (A) large cisterns excavated in
tuff 40 meters below Naples, Italy, and (B) part of
the 400-kilometer-long aqueduct system .................. 32
31. Schematic cross section of a kanat ...................... 32
32-35. Photographs showing:
32. Crypt of the Popes (left) and Crypt of Saint
Cecilia (right) in the Catacomb of Callixtus,
Rome, Italy ......................................... 33
33. A room in the underground city of Kaymakli,
Turkey .............................................. 34
34. Mitchell Caverns, California, showing a cracked
stalagmite near the entrance and an intact
delicate stalactite from deeper in the cave ......... 36
35. Soda straws ......................................... 36
36. Cross sections through two stalagmites from caves in
northeastern Italy ...................................... 38
37. Index map for the 1964 Good Friday earthquake in
Alaska showing location of tunnels near the epicenter
and approximate contours for earthquake intensity ....... 40
38. Illustration of placement of spent nuclear fuel
pellets within a fuel assembly and waste packages, and
degradation and mobilization of the waste form .......... 43
39. Photograph showing reactor zone in a natural fission
reactor at the Oklo orebody, Gabon ...................... 46
40. Schematic cross section showing depth of Okélobondo
natural fission reactor in relation to other Oklo
reactors ................................................ 48
41. Aggregate of (U,Zr)-silicate, zircon, galena, and
illite in the center of the Okélobondo reactor core
(RZOKE) ................................................. 49
42. Sequence of formation of uranyl minerals by alteration
of uraninite ............................................ 50
43. Schematic showing components of the engineered barrier
system proposed for Yucca Mountain in relation to
natural barriers ........................................ 55
44. Conceptual view of the drip shield assembly designed
to serve as a protective barrier to divert water
dripping from drift walls ............................... 56
45. Cross section of emplacement drift with engineered
barrier system components ............................... 57
46. Schematic view of different waste packages in
emplacement drift ....................................... 58
47. Processes affecting formation of high-salinity fluids
on the waste package surface ............................ 62
48. Photograph of the corrosion-resistant iron pillar at
Delhi, India ............................................ 64
49. Schematic showing development of rust coating on mild
steel, weathering steel, and Delhi iron pillar .......... 64
50-52. Photograph showing:
50. Josephinite sample used for surface analysis
study ............................................... 64
51. Chromite grains in serpentinite before (A) and
after (B) acid leachnig ............................. 66
52. Portion of Hadrian's Wall in England, showing
strength and stability of Roman mortar after 1,700
years ............................................... 66
53. Distribution of ophiolites and hyperalkaline springs
in northern Oman ........................................ 67
54. Stratigraphic section of drill hole UE-25 UZ#16, with
abundance of zeolites plotted relative to [A) alkaline
earth, and (B) alkali constituents ...................... 69
55. Fracture mineralization and wall rock alteration at
C353 site, Maqarin, Jordan, showing the presence of
hydrated calcium silicate and sulfate phases
thaumasite and ettringite ............................... 70
56. Schematic illustration of radionuclide transport in
a fractured rock ........................................ 71
57-63. Photographs showing:
57. Entrance to Mitchell Caverns in California, El
Pakiva portal, showing fallen blocks that
partially occlude the entrance ...................... 73
58. Fracture in the blackened wall and ceiling of
a kitchen in a monastery at Goreme, Turkey, which
was probably in use until the 12th century A.D ...... 74
59. (A) Building 810 on the Denver Federal Center,
Colorado, and (B) a closeup of the underside of
the roof over a loading dock ........................ 75
60. Interior of Alcove 1 of the Exploratory Studies
Facility, Yucca Mountain, Nevada .................... 75
61. The inside of a corbelled ceiling grave at
Newgrange, Ireland .................................. 76
62. Cheomachong tomb in Gyeongju, Korea ................. 77
63. Area of large mudcracks formed in the floor of
a tomb in the Valley of the Kings in Egypt .......... 78
64. Plan view of the regional model at the Idaho National
Laboratory with shading to illustrate ground surface
elevation ............................................... 82
65. Map of the Subsurface Disposal Area, Idaho National
Laboratory, and deep wells showing location of
radionuclide concentrations greater than three times
detection for depth intervals to the 9-meter interbed ... 85
66. Map of the Subsurface Disposal Area, Idaho National
Laboratory, and deep wells showing location of
radionuclide concentrations greater than three times
detection for depth intervals to the 34-meter
interbed ................................................ 85
67. Map of the Subsurface Disposal Area, Idaho National
Laboratory, and deep wells showing location of
radionuclide concentrations greater than three times
detection for depth intervals to the 73-meter
interbed ................................................ 86
68. Depths and elevations of perched water in the vicinity
of the Subsurface Disposal Area, Idaho National
Laboratory .............................................. 86
69. Comparison of FEHM and FLOTRAN for normalized tracer
concentration after 50 years for the single-continuum
model of the Subsurface Disposal Area, Idaho National
Laboratory, with steady release at the center of the
injection region ........................................ 88
70. Liquid saturation for fracture continuum in model of
the Subsurface Disposal Area, Idaho National
Laboratory .............................................. 88
71. Liquid saturation for matrix continuum in model of the
Subsurface Disposal Area, Idaho National Laboratory ..... 89
72. Comparison of steady-state saturation profiles for
single- and dual-continuum simulations in model of the
Subsurface Disposal Area, Idaho National Laboratory ..... 89
73. Normalized tracer concentration for fracture continuum
in dual-continuum transport model of the Subsurface
Disposal Area, Idaho National Laboratory ................ 90
74. Normalized tracer concentration for matrix continuum
in dual-continuum transport model of the Subsurface
Disposal Area, Idaho National Laboratory ................ 90
75. Normalized tracer concentration after 50 years for the
single-continuum model of the Subsurface Disposal
Area, Idaho National Laboratory, with constant
release ................................................. 91
76. Hydrostratigraphy of the Subsurface Disposal Area,
Idaho National Laboratory ............................... 92
77. Steady-state water potentials at the Subsurface
Disposal Area, Idaho National Laboratory ................ 92
78. Liquid saturation at 50 years in the dipping,
continuous layer transport model of the Subsurface
Disposal Area, Idaho National Laboratory ................ 93
79. Normalized tracer concentration at 50 years in the
dipping, continuous layer transport model of the
Subsurface Disposal Area, Idaho National Laboratory ..... 93
80. Comparison of field data to model for sorption of
cesium, plutonium, americium, and strontium for a flow
velocity of 0.1 meter per year through the surficial
sediment at the Subsurface Disposal Area, Idaho
National Laboratory ..................................... 96
81. Nopal l uranium deposit in the Pena Blanca Mining
District, Chihuahua, Mexico ............................. 97
82. Orthogonal, vertical cross sections through
observation well PB 1 of the Nopal l deposit,
Chihuahua, Mexico ....................................... 98
83. Relative sequence of formation and abundance of
uranium minerals atthe Nopal l deposit, Chihuahua,
Mexico .................................................. 99
84. Plan view of the Nopal l deposit ....................... 100
85. Plot of measurements of 234U/23238U compared to
230Th/23238U for fracture-filling materials,
Nopal l area, Chihuahua, Mexico, obtained by the
Center for Nuclear Waste Regulatory Analyses ........... 101
86. 234U/238U activity ratios at distances from edge of
the Nopal l deposit, Chihuahua, Mexico, for the
fracture samples ....................................... 105
87. 238U-234U-230Th systematics for fracture-filling
materials at Peña Blanca, Chihuahua, Mexico ............ 106
88. 230Th-226Ra systematics (plotted as activity ratio)
for fracture-filling materials at Peña Blanca,
Chihuahua, Mexico ...................................... 106
89. Schematic of Nopal l Level +00 Adit sampling
locations. Chihuahua, Mexico ........................... 107
90. Photograph of sampling locations A, B, and С in the
Nopal l +00 Adit, Chihuahua, Mexico .................... 107
91. Plot showing stable isotope ratios for waters
collected from the Nopal l adit, Peña Blanca,
Chihuahua, Mexico ...................................... 108
92. Portion of topographic map showing locations of Nopal
l ore deposit and Peña Blanca wells, Peña Blanca,
Chihuahua, Mexico ...................................... 109
93. Panoramic view of the wells drilled in 2003, Pena
Blanca, Chihuahua, Mexico .............................. 110
94-96. Graphs showing:
94. Uranium isotope systematics and mixing lines for
(A) unsaturated-zone and (B) saturated-zone
waters, Peña Blanca, Chihuahua, Mexico ............. 110
95. Decrease in uranium (U) concentrations in 2003-
drilled well waters and well development
overtime, Peña Blanca, Chihuahua, Mexico .......... 111
96. Strontium (Sr) isotope mixing diagram for
unsaturated-zone adit waters and saturated-zone
ranch well waters, Peña Blanca, Chihuahua,
Mexico ............................................. 113
97. Map showing location of the uranium orebodies in
the Alligator Rivers region, Northern Territory,
Australia .............................................. 115
98. Cross section through the Koongarra, Alligator
Rivers, Australia, orebody showing the distribution
of the major rock types and uranium-bearing minerals ... 116
99. Location of Steenkampskraal, South Africa .............. 117
100.Comparison of processes in geothermal and
anthropogenic thermal systems created by emplacing
heat-generating nuclear waste in an unsaturated
fractured rock mass .................................... 119
101.Photograph of Porkchop Geyser, Yellowstone National
Park, Wyoming .......................................... 120
102.Calculated changes in sodium-potassium-calcium (NKC)
reservoir temperatures and silica (Si02)
concentrations for waters sampled from Porkchop
Geyser, Yellowstone National Park, Wyoming ............. 121
103.Photomicrograph of altered Rainier Mesa Tuff, Nevada ... 123
104.Location map of the Osamu Utsumi Mine and Morro do
Ferro study sites at Pogos de Caldas, Minas Gerais,
Brazil ................................................. 129
105.North-south cross section of the El Berrocal, Spain,
granite-uranium-quartz vein system and location of
selected boreholes ..................................... 131
106.Lithology at Palmottu, Finland, with respective
uranium and thorium contents ........................... 132
107.Idealized cross section of a fossil reactor zone at
Oklo and Bangombe, Gabon ............................... 133
108.Schematic representation of groundwater flow paths
in the Bangombé area, Gabon ............................ 133
109.Geology of the Tono, Japan, natural analogue study
site. (A) Tono mine site, including regional geology.
(B) Cross section through the Tsukiyoshi orebody
(black) showing its faulted nature ..................... 135
110.(A) Locations of the Uranium Mill Tailings Recovery
Act groundwater project sites. (6) Location map for
the Gunnison, Colorado, Uranium Mill Tailings
Recovery Act site ...................................... 139
111.Plume map of sulfate concentrations, in milligrams
per liter, in alluvial groundwater atthe Gunnison,
Colorado, Uranium Mill Tailings Recovery Act site ...... 140
112.Plume map of uranium concentrations, in milligrams
per liter, in alluvial groundwater at the Gunnison,
Colorado, Uranium Mill Tailings Recovery Act site ...... 141
113.Location map for the New Rifle, Colorado, Uranium
Mill Tailings Recovery Act site ........................ 142
114.Aerial photograph of the New Rifle, Colorado,
Uranium Mill Tailings Recovery Act site, showing
location of tailings piles in August 1974 .............. 142
115.Map showing locations of wells screened in the
alluvial aquifer at the New Rifle, Colorado, Uranium
Mill Tailings Recovery Act site ........................ 143
116.Sulfate-chloride (SO4/Cl) ratios in downgradient
alluvial groundwater relative to distance in feet
from the Colorado River bank on the eastern edge of
the New Rifle, Colorado, Uranium Mill Tailings
Recovery Act site ...................................... 144
117.Uranium concentration in downgradient alluvial
groundwater relative to distance in feet from the
Colorado River bank on the eastern edge of the New
Rifle, Colorado, Uranium Mill Tailings Recovery Act
site ................................................... 144
118.Decrease in normalized concentrations of selected
radionuclides in the Snake River Plain aquifer with
distance from the Idaho Chemical Processing Plant,
Idaho .................................................. 146
119.The function of natural analogues and site
characterization in performance assessment ............. 149
Tables
1. Items preserved within the unsaturated zone as
reported by National Geographic magazine from 1987 to
2001 ........................................................ 20
2. Elemental distribution within uraninite, inclusions, and
clays for elements in the reactor zones at Oklo, Gabon ...... 46
3. Comparison of volcanic glass and nuclear waste glass
compositions, in weight percent ............................. 51
4. Chemical composition of Alloy 22 ............................ 56
5. Commercial spent-nuclear-fuel waste package ................. 58
6. Chemical composition of stainless steel type 316NG .......... 59
7. Composition of synthetic Yucca Mountain waters from
unsaturated and saturated zones and their evaporated
compositions ................................................ 62
8. Typical Salton Sea geothermal well brine composition ........ 63
9. Chemical characteristics of selected samples of pore
water, perched water, and groundwater from Yucca Mountain
and the Subsurface Disposal Area of the Idaho National
Laboratory .................................................. 84
10.Additional water inputs to the Idaho National Laboratory
Subsurface Disposal Area due to flooding .................... 87
11.Composition of injected fluid used in model of Subsurface
Disposal Area transport ..................................... 94
12.Measurements of concentration and isotopic composition in
water samples collected nearthe Nopal l uranium deposit,
Peña Blanca, Mexico ........................................ 102
13.Comparison of Peña Blanca and Yucca Mountain water
samples .................................................... 112
14.Application of geothermal field information as analogues
to coupled processes anticipated atthe proposed Yucca
Mountain, Nevada, repository ............................... 126
15.Natural analogues discussed in this report and their
potential application to Yucca Mountain performance
assessment ................................................. 153
Appendix Table. Known caves with assigned ages and the
methods of age determination .................................. 184
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