//h37 CNWRA 90-008 GEOCHEMICAL NATURAL ANALOGS LITERATURE REVIEW Prepared for Nuclear Regulatory Commission Contract NRC-02-88-005 Prepared by E.C. Pearcy W.M. Murphy Center for Nuclear Waste Regulatory Analyses San Antonio, Texas June 1991 ABSTRACT The Geochemical Natural Analogs Project is designed to provide knowledge of the state of the art in natural analog studies applied to contaminant transport. Task 1 of the project, "Literature Review and Workshop," has been completed and the results are presented herein. The high-level waste literature has been reviewed for applications of natural analog studies. From these studies, the usefulness and the limitations of natural analogs have been ascertained and are considered in light of the regulatory interest in natural analog investigations in support of the siting of a high- level waste repository. Processes and events likely to control contaminant transport at Yucca Mountain are identified in this report and those processes which are amenable to natural analog study are discussed. A set of criteria for the selection and successful use of natural analog studies is presented. Based on this information, candidate sites for a natural analog study relevant to Yucca Mountain are proposed. These sites are the Pefia Blanca, Mexico, uranium deposits and the Santorini, Greece, archaeologic sites. Descriptions of these sites and discussions of their potential usefulness are included. TABLE OF CONTENTS Page EXECUTIVE SUMMARY ...................................................................... i 1. INTRODUCTION ...................................................................... 1 1.1 Uses of natural analogs for high-level waste repository planning ........................ 2 1.2 Limitations of natural analog studies ......................................................... 3 1.3 W hat can natural analog studies provide? .................................................... 4 2. NATURAL ANALOG STUDIES . .................................................................... 6 2.1 Ore deposit studies ...................................................................... 6 2.1.1 Oklo, Gabon ...................................................................... 6 2.1.2 Alligator Rivers, Australia ......................................................... 9 2.1.3 Pocos de Caldas, Brazil ............................................................ 12 2.1.4 Cigar Lake, Canada ................................................................. 15 2.1.5 Other ore deposit analog studies ................................................... 17 2.1.5.1 Palmottu, Finland ........................................................ 17 2.1.5.2 Portage Lake, M ichigan ................................................. 17 2.1.5.3 Krunkelbach, Germany ................................................. 18 2.1.5.4 Shinkolobwe, Zaire ...................................................... 18 2.1.5.5 Tono, Japan .............................................................. 19 2.1.5.6 Stripa, Sweden ........................................................... 19 2.2 Igneous contact zones ...................................................................... 20 2.2.1 Eldora Stock, Colorado ................................................... 20 2.2.2 Alamosa River Stock, Colorado .......................................... 21 2.2.3 M afics intruding evaporites ............................................... 21 2.2.4 Valles Caldera, New Mexico ............................................. 22 2.2.5 Oriciatico intrusion, Italy .................................................. 23 2.3 Glass alteration ...................................................................... 23 2.3.1 Basaltic glass ............................................................... 23 2.3.2 Rhyolitic glass .............................................................. 24 2.3.3 Tektites ...................................................................... 25 2.3.4 Archaeologic glass ......................................................... 25 * S 2.4 Miscellaneous natural analogs ................................................................. 26 2.4.1 Nuclear explosion sites ............................................................. 26 2.4.2 Uraniferous nodules................................................................ 27 2.4.3 Sediment studies..................................................................... 27 2.4.3.1 Boom Clay, Belgium .................................................... 27 2.4.3.2 Loch Lomond, UK ...................................................... 28 2.4.3.3 Redbeds, Switzerland ................................................... 28 2.3.4.4 Madeira Abyssal Plain, UK ............................................ 29 2.3.4.5 Gorleben Aquifer, Germany ............... ........................... 29 2.4.4 Hydrothermal analogs.............................................................. 30 2.4.4.1 Salton Sea, California ................................................... 30 2.4.4.2 Newberry, Oregon ....................................................... 30 2.4.4.3 Empire Creek Stock, Montana ......................................... 31 2.4.4.4 Icelandic geothermal fields .............................................. 31 2.4.5 Mine tailings.......................................................................... 32 2.4.5.1 South Terras, UK ........................................................ 32 2.4.5.2 Kennecott copper leaching ............................................. 32 2.4.6 Rock alteration ....................................................................... 33 2.4.6.1 Granite wave breaks, UK .............................................. 33 2.4.6.2 Grimsel, Switzerland .................................................... 33 2.4.6.3 Eye-Dashwa Lakes Pluton, Canada ................................... 34 2.4.7 Archaeologic analogs (other than glasses) . 34 2.4.7.1 Bronze cannon, Baltic Sea .............................................. 34 2.4.7.2 Gallo-roman cements, France .......................................... 35 2.4.8 Uraniferous veins .................................................................... 35 2.4.8.1 Marysvale, Utah ......................................................... 35 2.4.8.2 Needle's Eye, UK ....................................................... 36 2.4.8.3 Broubster, UK ........................................................... 36 3. CRITERIA FOR THE SUCCESSFUL USE OF NATURAL ANALOGS .. 36 4. PROCESSES AND EVENTS LIKELY TO CONTROL CONTAMINANT TRANSPORT AT YUCCA MOUNTAIN ...................................................................... 38 4.1 Processes important to contaminant transport at any HLW repository ... 38 4.2 Processes and events which are peculiar to contaminant transport at Yucca Mountain.. 39 4.3 Geochemical processes amenable to natural analog study .................................. 40 0 v 5. POTENTIAL SITES FOR A NATURAL ANALOG STUDY . 40 5.1 Yucca M ountain, Nevada ...................................................................... 40 5.2 Pefia Blanca, M exico ...................................................................... 42 5.3 M cDermitt Caldera, Nevada-Oregon ......................................................... 46 5.4 Santorini, Greece ...................................................................... 48 5.5 Conclusions ...................................................................... 50 6. REFERENCES. ........................................................................................... 53 7. ANNOTATED BIBLIOGRAPHY ...................................................................... 64 GEOCHEMICAL NATURAL ANALOGS LITERATURE REVIEW E.C. Pearcy W.M. Murphy EXECUTIVE SUMMARY This paper is a review of the state of the art in natural analog studies applied to geologic disposal of high-level radioactive waste. The high-level waste (HLW) literature has been reviewed for applications of natural analog studies. Processes and events likely to control contaminant transport at Yucca Mountain are identified herein and those processes which are amenable to natural analog study are discussed. A set of criteria for the selection and successful use of natural analog studies is presented. Descriptions of candidate natural analog sites relevant to the proposed HLW repository at Yucca Mountain and discussions of their potential usefulness are included. Natural analogs are occurrences of materials or processes in nature that may be viewed as comparable to some aspect of a system of interest. Natural analog studies are particularly applicable to systems for geologic disposal of high-level nuclear waste because of the long time and large space scales required. Natural materials that approximate components of a repository may be studied to gain a better understanding of the behavior to be expected from the repository materials. Similarly, a process which occurs (or has occurred) in nature and which may be significant to the performance of a repository may be investigated to learn of possible effects on a repository system. The Environmental Protection Agency (EPA) rule 40 CFR Part 191 (section 191.13(a)) specifies that HLW must be isolated from the accessible environment (as i 0 0 defined in the regulations) for the first 10,000 years following closure of the repository. The Nuclear Regulatory Commission (NRC) rule 10 CFR Part 60 (sections 60.21(c)(1)(ii)(F) and 60.101(a)(2)) calls for use of natural analog studies to support analyses and models