High Level Radioactive Waste Disposal

The patented THOR ® steam reforming waste treatment technology has been selected by the Department of Energy (DOE) for treatment of Sodium Bearing Waste (SBW) at the Idaho National Laboratory (INL). SBW is an acidic waste created primarily from cleanup of the fuel reprocessing equipment at the Idaho Nuclear Technology and Engineering Center (INTEC) at the INL. The SBW contains high concentrations of nitric acid and alkali and aluminum nitrates, along with many other inorganic compounds, including substantial levels of radionuclides. As part of the implementation of the THOR ® process at INTEC, an engineering-scale test demonstration (ESTD) was conducted using a specially designed pilot plant located at Hazen Research, Inc. in Golden Colorado. The purpose of the ESTD was to confirm and optimize operation of the THOR ® dual fluidized bed steam reforming (FBSR) process for treating the SBW. The performance of the integrated FBSR thermal and off-gas systems was demonstrated while treating waste simulants representative of the actual SBW. Simulants were utilized that consisted of highly acidic nitrate solutions, with both dissolved and undissolved solids (UDS). The SBW simulant solutions were converted into a dry, granular solid, consisting of carbonate and aluminate product compounds. The successful performance of the integrated FBSR system was verified and demonstrated.

Deep (4-5 km) boreholes are emerging as a safe, secure, environmentally sound and potentially cost-effective option for disposal of high-level radioactive wastes, including plutonium. One reason this option has not been widely accepted for spent fuel is because stacking the containers in a borehole could create load stresses threatening their integrity with potential for releasing highly mobile radionuclides like 129 I before the borehole is filled and sealed. This problem can be overcome by using novel high-density support matrices deployed as fine metal shot along with the containers. Temperature distributions in and around the disposal are modelled to show how decay heat from the fuel can melt the shot within weeks of disposal to give a dense liquid in which the containers are almost weightless. Finally, within a few decades, this liquid will cool and solidify, entombing the waste containers in a base metal sarcophagus sealed into the host rock.

Simulations were done to examine the effects of ground-water withdrawals from wells J-13 and J-12 near Yucca Mountain, Nevada. These simulations were done using a two-dimensional finite-element model of the subregional groundwater flow system of Yucca Mountain and vicinity. Eight different withdrawal rates ranging from 36 gallons per minute (the minimum average for well J-13) to 1,390 gallons per minute (the maximum for both J-13 and J-12 combined) were used in conjunction with specific-yield values of 0.001, 0.005, and 0.01. Drawdown was analyzed for each withdrawal rate by plotting contours of drawdown after 10 years of simulated withdrawals, and by plotting drawdown as a function of time for model locations corresponding to well J-13, well J-12, one-half mile south of well J-12, 2 miles north of the town of Amargosa Valley, and about 5 miles northwest of the Ash Meadows area. Because the range in simulated withdrawal rate was large, the range in resultant drawdown was correspondingly large. The simulated drawdowns after 10 years for the withdrawal rate of 90 gallons per minute from well J-13, based on a specific yield of 0.01 (which was considered to be a minimum value for the aquifer system) were 0.95 foot at well J-13, 0.53 foot at Amargosa Valley, and 0.16 foot northwest of Ash Meadows.

In the context of the potential confinement of high-level radioactive wastes (HLW) within the clay Engineered Barrier System (EBS) in deep geological formations, the evolution of the retention properties of smectite when interacting with Fe(0) needs to be assessed. If some potential natural analogues describing iron-clay reactivity are easily found, metallic iron-clay interactions are poorly described in studies regarding the Earth. Therefore experimental investigations are needed. Several parameters influence Fe(0)-clay interactions, such as temperature, the interlayer composition of swelling clays, and the presence of octahedral Fe 3+ … From a geometrical point of view, it is thought that clay destabilization is mainly controlled by phenomena starting at the edge faces of the particles. In the present work, the rates of the smectite-Fe(0) reaction at 80°C was assessed by XRD, Mössbauer and CEC analyses for three smectites. The investigations show marked differences in the degree of stability, which can not be explained by the crystal-chemistry rules established in previous studies. Therefore, the Fe(0)-smectite interactions were studied in view of textural and energetic surface quantitative analyses. The studied smectites have equivalent nitrogen BET specific surface areas, equivalent argon edge surface areas and slightly different basal surface areas. This similarity in particle shape indicates that the edge surface area can not be accounted for when explaining the observed differences in reactivity. However, a correlation is obtained between smectite reactivity and the energetic heterogeneity of its edge faces. This is interpreted in terms of a multiplication of the number of sites on the edge faces, where the electron transfer between Fe(0) and the smectite structure can occur.

This paper summarizes preliminary remote handling and robotic concepts being developed as part of the US Department of Energy's (DOE) Yucca Mountain Project. The DOE is currently evaluating the Yucca Mountain Nevada site for suitability as a possible underground geologic repository for the disposal of high level nuclear waste. The current advanced conceptual design calls for the disposal of more than 12,000 high level nuclear waste packages within a 225 km underground network of tunnels and emplacement drifts. Many of the waste packages may weigh as much as 66 tonnes and measure 1.8 m in diameter and 5.6 m long. The waste packages will emit significant levels of radiation and heat. Therefore, remote handling is a cornerstone of the repository design and operating concepts. This paper discusses potential applications areas for robotics and remote handling technologies within the subsurface repository. It also summarizes the findings of a preliminary technology survey which reviewed available robotic and remote handling technologies developed within the nuclear, mining, rail and industrial robotics and automation industries, and at national laboratories, universities, and related research institutions and government agencies.

The performance assessment process and incorporated input assumptions for four active and one planned DOE disposal sites were analyzed using a systems approach. The sites selected were the Savannah River E-Area Slit and Engineered Trenches, Hanford Integrated Disposal Facility, Idaho Radioactive Waste Management Complex, Oak Ridge Environmental Management Waste Management Facility, and Nevada National Security Site Area 5. Each disposal facility evaluation incorporated three overall system components (1) site characteristics (climate, geology, geochemistry, etc.), (2) waste properties (waste form and package), and (3) engineered barrier designs (cover system, liner system). Site conceptual models were also analyzed to identity the main risk drivers and risk insights controlling performance for each disposal facility.

Viscosity is the most important process property of waste glass. Viscosity measurement is difficult and costs much. Non-bridging Oxygen (NBO) model which relates glass composition to viscosity had been developed for high level waste at the Savannah River Site (SRS). This research utilized this NBO model to predict the viscosity of KEPRI's 55 glasses. It was found that there was a linear relationship between the measured viscosity and the predicted viscosity. The NBO model could be used to predict glass viscosity in glass formulation development. However the precision of predicted viscosity is out of satisfaction because the composition ranges are very different between the SRS and KEPRI glasses. The modification of NBO calculation, which included modification of alkaline earth elements and TiO2, could not strikingly improve the precision of predicted values.

Spore forming bacteria, such as Bacillus subtilis, are considered of great importance in space-life sciences, mainly because of the spores" multi-resistant characteristics. This sets spores as potential contaminators, posing a threat to food preservation as well as to planetary protection. It is the spores" overall structure that enables them to be so resilient, and efforts to study their resistance mechanisms to several space conditions have been undertaken. However, the effects of ultra-high vacuum in spores´ viability are not well-known. Thus, it is our interest to open the spores" molecular treasure box and unravel the molecular mechanisms of spores´ resistance to desiccation conditions in ultra-high vacuum. For that, air-dried spores of B. subtilis, representing a wide set of 28 strains, were immobilized on stainless steel discs and exposed to ultra-high vacuum for 7 days. Each strain counts with specific knockout genes associated with numerous known molecular mechanisms of spore resistance to different space conditions: SASP (sspA, sspB, sspE), DPA (spoVF), core water content (dacB), spore coat layer (cotE, safA, cotE safA), spore crust (cotX cotYZ, cotVW), DNA repair by HR (homologous recombination), NHEJ (non-homologous end-joining), BER (base excision repair) (recA, ku ligD, nfo, exoA) and detoxification (mrgA, katX). Spore resistance to ultra-high vacuum showed to be mainly dependent on SASPs, which are crucial in DNA protection. Moreover, DNA repair in the exposed spores showed to involve mostly ExoA Nfo, meaning BER plays a more important role than HR (RecA), NHEJ and detoxification (KatX).

This report attempts to describe the geochemical foundations of the behavior of radionuclides in the environment. The information is obtained and applied in three interacting spheres of inquiry and analysis: 1) experimental studies and theoretical calculations, 2) field studies of contaminated and natural analog sites and 3) model predictions of radionuclide behavior in remediation and waste disposal. Analyses of the risks from radioactive contamination require estimation of the rates of release and dispersion of the radionuclides through potential exposure pathways. These processes are controlled by solubility, speciation, sorption, and colloidal transport, which are strong functions of the compositions of the groundwater and geomedia as well as the atomic structure of the radionuclides. The chemistry of the fission products is relatively simple compared to the actinides. Because of their relatively short half-lives, fission products account for a large fraction of the radioactivity in nuclear waste for the first several hundred years but do not represent a long-term hazard in the environment. The chemistry of the longer-lived actinides is complex; however, some trends in their behavior can be described. Actinide elements of a given oxidation state have either similar or systematically varying chemical properties due to similarities in ionic size, coordination number, valence, and electron structure. In dilute aqueous systems at neutral to basic pH, the dominant actinide species are hydroxy-and carbonato-complexes, and the solubility-limiting solid phases are commonly oxides, hydroxides or carbonates. In general, actinide sorption will decrease in the presence of ligands that complex with the radionuclide; sorption of the (IV) species of actinides (Np, Pu, U) is generally greater than of the (V) species. The geochemistry of key radionuclides in three different environments is described in this report. These include: 1) low ionic strength reducing waters from crystalline rocks at nuclear waste research 4 sites in Sweden; 2) oxic water from the J-13 well at Yucca Mountain, Nevada, the site of a proposed repository for high level nuclear waste (HLW) in tuffaceous rocks; and 3) reference brines associated with the Waste Isolation Pilot Plant (WIPP). The transport behaviors of radionuclides associated with the Chernobyl reactor accident and the Oklo Natural Reactor are described. These examples span wide temporal and spatial scales and include the rapid geochemical and physical processes important to nuclear reactor accidents or industrial discharges as well as the slower processes important to the geologic disposal of nuclear waste. Application of geochemical information to remediating or assessing the risk posed by radioactive contamination is the final subject of this report. After radioactive source terms have been removed, large volumes of soil and water with low but potentially hazardous levels of contamination may remain. For poorly-sorbing radionuclides, capture of contaminated water and removal of radionuclides may be possible using permeable reactive barriers and bioremediation. For strongly sorbing radionuclides, contaminant plumes will move very slowly. Through a combination of monitoring, regulations and modeling, it may be possible to have confidence that they will not be a hazard to current or future populations. Abstraction of the hydrogeochemical properties of real systems into simple models is required for probabilistic risk assessment. Simplifications in solubility and sorption models used in performance assessment calculations for the WIPP and the proposed HLW repository at Yucca Mountain are briefly described. ACKNOWLEDGEMENTS. The authors would like to thank our colleagues who reviewed this document for technical content, including Pat Brady,

The backfilling and sealing of shafts and galleries is an essential part of the design of underground repositories for high-level radioactive waste. Part of the EC funded project RESEAL studied the feasibility of sealing off a borehole in plastic Boom Clay by means of pre-compacted bentonite blocks. Two bentonites, namely the FoCa and Serrata clay, have been used. Based on laboratory tests, the bentonite blocks had an initial dry density of about 1.8 g/cm 3 to obtain a swelling pressure of about 4.4 MPa, corresponding to the in situ lithostatic stress, at full saturation. The set-up was equipped with several sensors to follow-up the behaviour of the seal and the surrounding host rock during hydration. Full saturation was reached after five months and was mainly reached by natural hydration. Swelling pressure was lower than originally foreseen due to the slow reconsolidation of the host rock. Later on, the efficiency of the seal with respect to water, gas and radionuclide migration was tested. The in situ measured permeability of the seals was about 5 • 10 À13 m/s. A gas breakthrough experiment did not show any preferential gas migration through the seal. No evidences of a preferential pathway could be detected from 125 I tracer test results.

The Low Activity Waste Pretreatment System (LAWPS) is being designed to enable the direct feed of waste to the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) facility to be immobilized. Prior to construction of the LAWPS, pilot-scale integrated testing of the key unit operations (crossflow filtration, ion exchange using spherical resorcinol-formaldehyde (sRF) resin) will be conducted by a team led by Washington River Protection Solutions (WRPS) to increase the technology maturation level of the facility’s critical technology elements. As a part of this effort, Pacific Northwest National Laboratory (PNNL) has conducted a series of tests to perform two major objectives: (1) support pilot-scale integrated testing of the LAWPS by supplying information or performance data in advance of operating the pilot-scale facility (1/9th scale); and (2) collect data needed to establish or confirm assumptions/approaches planned for implementation in the LAWPS sa...

The proposed high-level radioactive waste repository at Yucca Mountain, Nevada, is located within an active volcanic field. Probabilistic volcanic hazard models for future eruptions through the proposed repository depend heavily on our understanding of the spatial controls on volcano distribution at a variety of scales. On regional scales, Pliocene-Quaternary volcano clusters are located east of the Bare Mountain fault. Extension has resulted in large-scale crustal density contrast across the fault, and vents are restricted to low-density areas of the hanging wall. Finite element modeling indicates that this crustal density contrast can result in transient pressure changes of up to 7 MPa at 40 km depth, providing a mechanism to generate partial melts in areas where mantle rocks are already close to their solidus. On subregional scales, vent alignments, including one alignment newly recognized by ground magnetic mapping, parallel the trends of high-dilation tendency faults in the Yucca Mountain region (YMR). Forty percent of vents in the YMR are part of vent alignments that vary in length from 2 to 16 km. Locally, new geological and geophysical data show that individual vents and short vent alignments occur along and adjacent to faults, particularly at fault intersections, and leftstepping en echelon fault segments adjacent to Yucca Mountain. Conditions which formed these structures persist in the YMR today, indicating that volcanism will likely continue in the region and that the proposed repository site is within an area where future volcanism may occur. On the basis of these data the probability of volcanic disruptions of the proposed repository is estimated between 10-8/yr and 10-7/yr. 1. Introduction Volcanic hazard analyses are often required for facilities, such as nuclear power plants and high-level radioactive waste repositories, that must be constructed in areas of low geologic risk [International Atomic Energy Agency, 1997]. The proposed high-level radioactive waste repository at Yucca Mountain, Nevada, is one such facility. Plans call for this repository to isolate high-level radioactive waste for a time period of the order of 104-105 years [e.g., Krauskopf, 1988; U.S. Nuclear Waste Technical Review Board, 1994; U.S. National Research Council, 1995]. Volcanic hazards associated with the repository stem from its location within a geologically active basaltic volcanic field that includes --•40 basaltic vents formed since 10.5 Ma and, notably, six cinder cones formed since 1 Ma that are located within 20 km of the site (Figures la and lb) [Crowe et al., 1983; Connor and Hill, 1995; Fleck et al., 1996]. This Quaternary basaltic volcanism is deleterious because of the potential for small-volume basaltic eruptions through the repository that are capable of transporting waste into the environment. In order to effectively evaluate this hazard in light of the pro-•Center for Nuclear Waste Regulatory Analyses, Southwest Re-

Most of the peoples of the Great Basin were Shoshonean-speakers of the Utaztecan language family. In northern and eastern Utah were bands of Utes. Various groups of Shoshonia lived in the north from eastern Oregon to Wyoming’s Wind River, and Northern and Southern Paiutes extended across most of the southern and western parts of the region.  By about 9,000 years ago the region was characterized by the Desert Culture, which existed into historic times. The culture included the use of netting, milling stones, scraper and chopping tools, digging sticks and basketry. About 6,000 years ago members of the Utaztecan-speaking group, including the Shoshonean people, migrated south along the west slope of the Rockies and into the Great Basin. Between 4,000 and 2,000 years ago, the some of the Basin peoples began using mortars and pestles instead of milling stones, fishhooks, and even duck decoys. They gathered acorns and pine nuts and began living in wickiups. These were conical structures with a framework of willow or juniper poles covered by brush, bark, or grass matting. In the center was a firepit with a smoke hole in the roof above.

Around 1700 some of the eastern band of Shoshone acquired horses, which enabled them to roam into the Great Plains to hunt buffalo. They also began to adopt some of the Great Plains culture, including feathered headdresses. They expanded as far as southern Alberta province in Canada, where the Blackfeet finally drove them out. Another group of Paiute Bannocks migrated into Shoshoni territory in southern Idaho, where they joined the Shoshoni as mounted buffalo hunters. In the northern parts of the Columbia Basin were the Salish-speaking Flatheads. Along the lower Snake River Basin were the Sahaptin-speaking  Nez Percés, a dialect of the Penutian language family. Other Penutian-speaking peoples were the Klamaths in south central Oregon, and the Modocs near the Oregon-California border.

Like the peoples of the Great Basin, the Plateau people were part of the larger Desert Culture. But about 4,500 years ago, their culture diverged as fishing along the region’s rivers became more dominant. Between 500 and 1000 A.D. as trade increased with the peoples of the Pacific Coast, their social organization became more complex, and shortly before the contact with Whites they too adopted elements of the Great Plains culture. When the White men came to the Plateau region in the early nineteenth century, these peoples were living in small, semi-permanent fishing villages along rivers and streams.

Northwestern Shoshone in southern Idaho and northern Utah; the Northern Shoshone in northern Utah and south and central Idaho; the Eastern Shoshone in western Wyoming; the Lemhi Shoshone along the Salmon River in central Idaho; the Gosiute or Western Shoshone in western and northwestern Utah. The Lemhi Shoshones were the northern most of the Northern Shoshone. The Lemhi Shoshone were comprised of several smaller groups, including the Agaidikas (Salmoneaters), Tukudekas (Sheepeaters), and Kucundikas (Buffaloeaters). After the introduction of the horse, some Northern Paiute-speaking Bannocks, who came from eastern Oregon to Fort Hill in the mid-nineteenth century, joined Kukundikas in the Lemhi Valley. The Bannocks were Western-Numic-speaking Northern Paiutes, who migrated from the northern Great Basin in the eighteenth century. They integrated by marriage into the Shoshone of the Portnuef and Snake River valleys.

The Nez Percé country encompassed what is today southeastern Washington, northeastern Oregon, and northcentral Idaho. Its eastern boundary was the Bitterroot Mountains and the western boundary was the Blue and Wallow mountain ranges. The principal rivers were the Snake and its tributaries the Clearwater and Salmon rivers. Salmon was their main staple. The northern bands or Upper Nez Percés along the Clearwater River went on annual buffalo hunts on the Great Plains in an alliance with the Crows. The  southern bands or Lower Nez Percés along the Snake and Salmon rivers seldom left the Nez Percé homeland.

The Southern Ute tribe represents a culturally intermediate position in the evolution of Uto-Aztecan peoples,” writes Marvin K. Opler.  The Southern Utes territory was in western Colorado, with the Paiute to the west in Utah, the Northern Shoshones to the north and the Navaho to the south in New Mexico. The Aztecs were further south across the Mexican border (See, Apache and Navaho). The Gunnison River separated the Northern Utes from the Southern Utes. Before the introduction of the horse the Utes were unable to live in agricultural villages, because in the fall and winter, snow in the passes and even the foothills of the Rockies made travel made agriculture impossible. The Southern Utes in the region below the Gunnison River could only settle in large band encampments in the spring and summer. Their traditional houses were wickiups. In the fall and winter they needed to migrate south to the border with the Comanche, Apache, and Navaho.

The U.S. Department of Energy (DOE) is considering the possible recommendation of a site at Yucca Mountain, Nevada, for the potential development of a geologic repository for the disposal of high-level radioactive waste and spent nuclear fuel. Consequences of hypothetical disruption of the Yucca Mountain site by igneous activity or human intrusion have been evaluated in the Yucca Mountain Science and Engineering Report (S&ER) (1), which presents technical information supporting the consideration of the possible site recommendation. Since completion of the S&ER, supplemental analyses have examined possible impacts of new information and alternative assumptions on the estimates of the consequences of these events. Specifically, analyses of the consequences of igneous disruption address uncertainty regarding: 1) the impacts of changes in the repository footprint and waste package spacing on the probability of disruption; 2) impacts of alternative assumptions about the appropriate distribution of future wind speeds to use in the analysis; 3) effects of alternative assumptions about waste particle sizes; and 4) alternative assumptions about the number of waste packages damaged by igneous intrusion; and 5) alternative assumptions about the exposure pathways and the biosphere dose conversion factors used in the analysis. Additional supplemental analyses, supporting the Final Environmental Impact Statement (FEIS), have examined the results for both igneous disruption and human intrusion, recalculated for a receptor group located 18 kilometers (km) from the repository (the location specified in 40 CFR 197), rather than at the 20 km distance used in the S&ER analyses.

In May 1998, the United States Environmental Protection Agency (EPA) certified the United tates Department of Ener=g's (DOE) Waste Isolation Pilot Plant (WIPP) as being in compliance with applicable long-term regulations governing the permanent disposal of spent nuclear fuel, high-level, and transuranic radioactive wastes. The WIPP is the first deep geologic repository in the United States to have successfully demonstrated regulatory compliance with Iong-tetm radioactive waste disposal requirements. The first disposal of TRU waste at WIPP occurred on March 26, 1999. Many of the lessons learned during the WIPP Project's transition from site characterization and experimental research to the preparation of a successful application may be of general interest to other repository programs. During a four-year period (1992 to 1996), the WIPP team [including the DOE Carlsbad Area Office (CAO), the science advisor to C.AO, Sandla National Laboratories (SNL), and the management and operating contractor of the WIPP site, Westinghouse Electric Corporation (WID)] met its aggressive schedule for submitting the application without compromising the inte=tity of the scientific basis for the long-term safety of the repository. Strong leadership of the CAO -SNL -WID team was essential. Within SNL, a mature and robust performance assessment (PA) allowed prioritization of remaining scientific activities with respect to their impact on regulatory compliance. Early and frequent dialog with EPA staff expedited the review process after the application was submitted. Questions that faced SNL are familiar to geoscientists working in site evaluation projects. What data should be gathered during site characterization? How can we know when data are sufllcient? How can we know when our understanding of the disposal system is sufficient to support our conceptual models? What constitutes adequate "validation" of conceptual models for processes that act over geologic time? How should we use peer review and expert judgernent? Other lessons learned by SNL and the WIPP team are more specific to the regulatory context of the project and the demands imposed by pervasive review by the regulator and other external organizations. How should we document the relationship between site data and the parameter values used in computer models? How can we manage software configuration and use it to support the regulatory requirement that analyses be traceable and reproducible? Can we institute a quality assurance (QA) program that will meet the regulatory requirements and enhance the process without unreasonable budget and schedule impacts? How can we resolve technical disputes, both within the project and with external critics? HOWshould we involve regulators and stakeholders in the compliance process? The WIPP teams answers to these questions, and others iike them, were, in many cases, pragmatic solutions based on the needs of the pro-warn at the time. Some problems encountered and their solutions may be of limited interest. However, that it is possible to Iicense a geologic repository in a regulatory proceeding while incorporating meaningful public review and c~ticism is a lesson of general interest to all radioactive waste management programs. 10bcuries (2.7 x 1017becquerels), with the largest component of this activiEycoming from approximately 12,900 kg of plutonium.

The use of deep boreholes for the disposal of high level radioactive waste is reassessed, emphasizing key enabling technical features and their strong linkage to national and international fuel cycle policy. Emplacement 2 to 4 km deep in widely available granitic continental bedrock, under a 1 km caprock layer of high-integrity bedrock, is shown in this analysis to have the potential to provide sufficiently low host rock permeability to prevent radionuclide escape by transport in waterthe only plausible release mechanism. The modular nature of the concept enables multi-region siting in large user countries, and is especially well-suited for small-user nations. Irretrievability can be built-in to better meet safeguards objectives, and the exceptionally high assurance of confinement makes minor actinide (and troublesome fission product) disposal an attractive alternative to their destruction by transmutation.

The United States Department of Energy (DOE) is developing the Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico for the disposal of transuranic wastes generated by defense programs. Applicable regulations (40 CFR 191) require the DOE to evaluate disposal-system performance for 10,000 yr. Climatic changes may affect performance by altering greundwater flow. Paleoclimatic data from southeastern New Mexico and the surrounding area indicate that the wettest and coolest Quaternary climate at the site can be represented by that at the last glacial maximum, when mean annual precipitation was approximately twice that of the present. The hottest and driest climates have been similar to that of the present. The regularity of global glacial cycles during the late Pleistocene confirms that the climate of the last glacial maximum is suitable for use as a cooler and wetter bound for variability during the next 10,000 yr. Climate variability is incorporated into groundwater-flow modeling for WIPP PA by causing hydraulic head in a portion of the model-domain boundary to rise to the ground surface with hypothetical increases in precipitation during the next 10,000 yr. Variability in modeled disposal-system performance introduced by allowing head values to vary over this range is insignificant compared to variability resulting from other causes, including incomplete understanding of transport processes. Preliminary performance assessments suggest that climate variability will not affect regulatory compliance.

The U.S. Department of Energy (DOE) is considering the possible recommendation of a site at Yucca Mountain, Nevada, for the potential development of a geologic repository for the disposal of high-level radioactive waste and spent nuclear fuel. Consequences of hypothetical disruption of the Yucca Mountain site by igneous activity or human intrusion have been evaluated in the Yucca Mountain Science

Preliminary evaluation of deep borehole disposal of high-level radioactive waste and spent nuclear fuel indicates the potential for excellent long-term safety performance at costs competitive with mined repositories. Significant fluid flow through basement rock is prevented, in part, by low permeabilities, poorly connected transport pathways, and overburden self-sealing. Deep fluids also resist vertical movement because they are density stratified. Thermal hydrologic calculations estimate the thermal pulse from emplaced waste to be small (less than 20 o C at 10 meters from the borehole, for less than a few hundred years), and to result in maximum total vertical fluid movement of ~100 m. Reducing conditions will sharply limit solubilities of most dose-critical radionuclides at depth, and high ionic strengths of deep fluids will prevent colloidal transport. For the bounding analysis of this report, waste is envisioned to be emplaced as fuel assemblies stacked inside drill casing that are lowered, and emplaced using off-theshelf oilfield and geothermal drilling techniques, into the lower 1-2 km portion of a vertical borehole ~ 45 cm in diameter and 3-5 km deep, followed by borehole sealing. Deep borehole disposal of radioactive waste in the United States would require modifications to the Nuclear Waste Policy Act and to applicable regulatory standards for long-term performance set by the US Environmental Protection Agency (40 CFR part 191) and US Nuclear Regulatory Commission (10 CFR part 60). The performance analysis described here is based on the assumption that long-term standards for deep borehole disposal would be identical in the key regards to those prescribed for existing repositories (40 CFR part 197 and 10 CFR part 63).

It is likely that the ongoing process to produce the 1996 version of the IAEA Regulation for the Safe Transport of Radioactive Materials, IAEA Safety Series 6(SS 6) will result in a more stringent package qualification standard for air transport of large quantities of radioactive materials (RAM) than is included in the 1990 version. During the process to define the

Hanford currently has 212,000 m 3 (56 million gallons) of highly radioactive mixed waste stored in the Hanford tank farm. This waste will be processed to produce both high-level and low-level activity fractions, both of which are to be vitrified. Supplemental treatment options have been under evaluation for treating portions of the low-activity waste, as well as the liquid secondary waste from the low-activity waste vitrification process. One technology under consideration has been the THOR ® fluidized bed steam reforming process offered by THOR Treatment Technologies, LLC (TTT). As a follow-on effort to TTT's 2008 pilot plant FBSR non-radioactive demonstration for treating low-activity waste and waste treatment plant secondary waste, TTT, in conjunction with Savannah River National Laboratory, has completed a bench scale evaluation of this same technology on a chemically adjusted radioactive surrogate of Hanford's waste treatment plant secondary waste stream. This test generated a granular product that was subsequently formed into monoliths, using a geopolymer as the binding agent, that were subjected to compressibility testing, the Product Consistency Test and other leachability tests, and chemical composition analyses. This testing has demonstrated that the mineralized waste form, produced by co-processing waste with kaolin clay using the TTT process, is as durable as low-activity waste glass . Testing has shown the resulting monolith waste form is durable, leach resistant, and chemically stable, and has the added benefit of capturing and retaining the majority of Tc-99, I-129, and other target species at high levels.

The Waste Treatment and Immobilization Plant (WTP) process flow was designed to pre-treat feed from the Hanford tank farms, separate it into a High Level Waste (HLW) and Low Activity Waste (LAW) fraction and vitrify each fraction in separate facilities. Vitrification of the waste generates an aqueous condensate stream from the off-gas processes. This stream originates from two off-gas treatment unit operations, the Submerged Bed Scrubber (SBS) and the Wet Electrospray Precipitator (WESP). Currently, the baseline plan for disposition of the stream from the LAW melter is to recycle it to the Pretreatment facility where it gets evaporated and processed into the LAW melter again. If the Pretreatment facility is not available, the baseline disposition pathway is not viable. Additionally, some components in the stream are volatile at melter temperatures, thereby accumulating to high concentrations in the scrubbed stream. It would be highly beneficial to divert this stream to an alternate disposition path to alleviate the close-coupled operation of the LAW vitrification and Pretreatment facilities, and to improve long-term throughput and efficiency of the WTP system. In order to determine an alternate disposition path for the LAW SBS/WESP Recycle stream, a range of options are being studied. A simulant of the LAW Off-Gas Condensate was developed, based on the projected composition of this stream, and comparison with pilot-scale testing. The primary radionuclide that vaporizes and accumulates in the stream is Tc-99, but small amounts of several other radionuclides are also projected to be present in this stream. The processes being investigated for managing this stream includes evaporation and radionuclide removal via precipitation and adsorption. During evaporation, it is of interest to investigate the formation of insoluble solids to avoid scaling and plugging of equipment. Key parameters for radionuclide removal include identifying effective precipitation or ion adsorption chemicals, solid-liquid separation methods, and achievable decontamination factors. Results of the radionuclide removal testing indicate that the radionuclides, including Tc-99, can be removed with inorganic sorbents and precipitating agents. Evaporation test results indicate that the simulant can be evaporated to fairly high concentration prior to formation of appreciable solids, but corrosion has not yet been examined.

Liquid high-level nuclear waste at the Savannah River Site (SRS) will be immobilized by viwification in borosilicate glass. The glass will be produced and poured into stainless steel • canisters in the Defense Waste Processing Facility (DWPF). Other waste form producers, such as West Valley Nuclear Services (WVNS) and the Hanford Waste Vitrification Project (HWVP), will also immobilize high-level radioactive waste in borosilicate glass. The canistered waste will be , stored temporarily at each facility for eventual permanent disposal in a geologic repository. The Department of Energy has defined a set of requirements for the canistered waste forms, the Waste Acceptance Product Specifications (WAPS). The current Waste Acceptance Preliminary Specification (WAPS) 1.3, the product consistency specification, requires the waste form producers to demonstrate control of the consistency of the final waste form using a crushed glass durability test, the Product Consistency Test (PCT). In order to be acceptable, a waste glass must be more durable during PCT analysis than the waste glass identified in the DWPF Environmental Assessment (EA). In order to supply ali the waste form producers with the same standard benchmark glass, 1000 pounds of the EA glass was fabricated. The chemical analyses and characterization of the benchmark EA glass are reported. This material is now available to act as a durability and/or redox Standard Reference Material (SRM) for ali waste form producers.

In the aftermath of the Cold War, the United States Department of Energy (DOE) has identified up to 50 metric tons of excess plutonium that needs to be dispositioned. The bulk of the material is slated to be blended with uranium and fabricated into a Mixed Oxide (MOX) fuel for subsequent burning in commercial nuclear reactors. Excess plutonium-containing impurity materials

A team led by BNFL, Inc. was awarded the contract to remediate and immobilize the Hanford radioactive tank waste in support of the Hanford River Protection Program (RPP). BNFL, Inc. is teamed with BNFL Engineering, LTD., Bechtel National, GTS Duratek, and Science Application International Corporation to develop and design integrated facilities for pretreatment and vitrification in support of the RPP mission. This facility will pretreat and immobilize approximately 0.375 MT/day of high level waste (HLW, producing 1.5 MT/day of HLW glass) and approximately 4.5 MT/day of low activity waste (LAW, producing 30 MT/day of LAW glass). During the initial phase of the project (FY98 -FY00), the technology will be validated and optimized to the point that it can be used as the basis for final design, construction, and operation of a vitrification facility in Hanford, Washington.

This work was supported by fhe Yucca Mounfain Site Characterization Oflice as part of the Civilian Radioactive Waste Management Program. This project is managed by the U.S. Department of Energy, Yucca Mounfain Site Characterizafion Project. A list of notebooks and samples used to obtain data cited in fhis report will be included as an appendix to this report. The appendix will be issued by December 31, 1995; ifs unique idenfzfier assigned to fhis appendix is LA-EES-13-LV-12-95-002. To obtain rgerences bgore fhe appendix is issued, confacf Kean Finnegan at (7021-794-7273. The Los AIamos data tracking number for fhis work is LA000000000093.001. An Afirmative ActionEqual Opportunity Employer This report was prepared as an account ofwork sponsored by an agency of the United States Government. Neither The Regents of the University of California, fhe United States Government nor any agency thereof, nor any of their employees, makes m y warranty, express or implied, or assumes any legal liability or responsibilityfm the accuracy, completeness, or uspFtlness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe prioately owned rights. Rejierence herein to any specific commercial product, process, or service by trade name, trademark, manufncturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or fmm'ng by The Regents ofthe University ofCalfmia, the United States Government, or any agency thereoj The views and opinions ofauthors expressed herein do not necessarily state or rej7ect those of The Regents of the University of Califatin, the United States Gbvemment, or any agency there4 DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document.

1. Geologic map of Exile Hill area 2. Map of prospective facilities site 3. Map showing geophysical survey lines and features interpreted from geophysical data 4-7. Logs of: 4A. Trench MWV-T5, (stations 0-200) 4B. Trench MWV-T5, (stations 200-340) 5. Trench MWV-T4 6. Trench MWV-T7 7. Trench A/BR-3 8. Log and map of North Portal Duct Bank excavation 9. Logs of soil test pits V 11. Graphs showing results of gravity and ground magnetic surveys in Midway Valley.

Numerical methods have been applied for the prediction of colloid-facilitated radionuclide transport through water-saturated fractured porous rock. The presence of colloids may enhance the transport of radionuclides in groundwater by reducing retardation effects. The colloids existing in the groundwater act as carriers, adsorbing radionuelides in their large surface area and moving faster than the average water velocity. With colloids present, the system consists of three phases, i.e. an aqueous phase, a carrier phase and a stationary solid phase. In the basic model, onedimensional advection in a single planar fracture of infinite extent is coupled with diffusion in the rock matrix perpendicular to the fracture. In this study, a full-equilibrium model was developed to describe the transport and fate of the radionuelides in the fracture. Sorption onto the rock matrix, fracture surface and sorption onto mobile and immobile colloids are included. The effect of colloidal particle size was also considered. Mass partition mechanisms between the colloids and solid matrix and between colloid and contaminant are represented by local equilibrium. In the three-phase system, the three parameters, the retardation coefficient, the hydrodynamic dispersion coefficient and fracture width, are modified to include the equilibrium distribution coefficient of a contaminant with a carrier. In the three-phase model, much smaller retardation and hydrodynamic dispersion coefficients are obtained and the effect of the fracture width is larger. Much faster transport of contaminant has resulted mainly because the radionuclides attached to colloidal particles are not subject to retardation by diffusion into the rock matrix. With the additional consideration of colloidal particle sizes, these effects become ever larger. Numerical solutions for the model were obtained using a fully implicit finite difference scheme. A significant sensitivity to model parameters was discovered, and, in particular, the equilibrium distribution coefficients between a contaminant and the carrier were found to be the most important factors.

The gradual buildup of rare isotopes from interactions between cosmic rays and atoms in an exposed rock provides a new method of directly determining the exposure age of rock surfaces. The cosmogenic nuclide method can also provide constraints on erosion rates and the length of time surface exposure was interrupted by burial. Numerous successful applications of the technique have been imperative to the complete surface geologic characterization of Yucca Mountain, Nevada, a potential high level nuclear waste repository. The 10Be exposure age of Black Cone lava, within a ten mile radius of the proposed repository site, is 840 ± 210 kyr (in agreement with previous K/Ar dates of 1.0 ± 0.1 Ma). Rates of erosion of the tuff bedrock (< 0.4 cm/kyr from 7 10Be measurements) and of hillslope colluvium (∼ 0.5 cm/kyr from 10Be dates on boulder deposits) preclude denudation of the mountain as a concern. Neotectonic concerns (rate of slip and timing of last significant movement along faults) a...

1. Geologic map of Exile Hill area 2. Map of prospective facilities site 3. Map showing geophysical survey lines and features interpreted from geophysical data 4-7. Logs of: 4A. Trench MWV-T5, (stations 0-200) 4B. Trench MWV-T5, (stations 200-340) 5. Trench MWV-T4 6. Trench MWV-T7 7. Trench A/BR-3 8. Log and map of North Portal Duct Bank excavation 9. Logs of soil test pits V 11. Graphs showing results of gravity and ground magnetic surveys in Midway Valley.

High level waste containers may be constructed from Alloys 516 and C-22. Empirical correlations are presented that are useful in predicting the corrosion rates of these materials as functions of temperature, pH, and the concentrations of other corrodants. These correlations are based upon data bdng collected in the Long Term Corrosion Test Facility at Lawrence Liverrnore Natiinal Laboratory, as well as data published in the literature.

As part of the Swiss programme for high-level radioactive-waste disposal, a Jurassic shale (Opalinus Clay) is being investigated as a potential host rock. Observations in clay pits and the results of a German research programme focusing on hazardous waste disposal have demonstrated that, at depths of 10-30 m, the permeability of the Opalinus Clay decreases by several orders of magnitude. Hydraulic tests in deeper boreholes (test intervals below 300 m) yielded hydraulic conductivities <10 -12 m/s, even though joints and faults were included in some of the test intervals. These measurements are consistent with hydrogeological data from Opalinus Clay sections in ten tunnels in the Folded Jura of northern Switzerland. Despite extensive faulting, only a few indications of minor water inflow were encountered in more than 6,600 m of tunnel. All inflows were in tunnel sections where the overburden is less than 200 m. The hydraulic data are consistent with clay pore-water hydrochemical and isotopic data. The extensive hydrogeological data base -part of which derives from particularly unfavourable geological environments -provides arguments that advective transport through faults and joints is not a critical issue for the suitability of Opalinus Clay as a host rock for deep geological waste disposal.

At present, there are many bentonite exploitations located in the "Arcillas Verdes" Unit from the Tajo Basin (Brell, 1985; García Romero, 1988; Domínguez Díaz, 1994,etc). The high purity of these bentonites makes them very interesting and this is the cause of the study of the
geochemical, mineralogical and physical properties of them. Sorne of these properties have been studied before by different authors: (Galan et al. 1986, Cuevas, 1991). The main property of soil defining its behaviour is, not only its crystallographical and mineralogical nature, but also the type and distribution of clay particles and their tendency to be connected
to particle aggregates separated by voids of varying size. This is the reason why a study of the microstructure of the material as well as a more detailed" crystal structure investigation of the main mineral can be very useful to explain its physical-chemical and rheological behaviour.

Crystal structure detennination in poor crystalized minerals (e.g. smectites) has been traditionaly carried out by means of X-Ray powder diffraction; although by this technique is possible to distinguish between different structural types of minerals, it is not possible to resolve in detail the crystal structure.
The aim of this work is to put in evidence the effectiveness of the oblique texture electron diffraction patterns (OTEDP's) technique which is specially adequate for the structural study of layer minerals. Moreover, this technique is particularly useful for beam sensitive and low crystallinity minerals, where high resolution TEM images give poor crystallographic information. The use of OTED patterns has been frrstly developed in USSR in the groups of Zvyagin (1) and Vainshtein (2). With the help of electron diffraction cameras an'd using OTEDP's, crystal structures of severa! compounds have been studied (semiconductors, metals, silicates ... ). A recent review of all this work appears in the lnternational Tables .for X-Ray Crystallography (3). More recent investigations by Drits (4) on clay minerals show that crystal structure problems like polytypism or
the presence ( or not) of different cations in different crystallographic positions can be sol ved with the use of OTEDP's. Again, Dorset (5) using direct method procedures has confrrmed the validity of crystal structure detennination of severa! clay minerals previously solved by Zvyagin using this method.
The previous investigations (1-5), put in evidence the power of oblique texture electron diffraction patterns to resolve severa! structure problems of layer silicates like polytypism and cation location in different crystallographic positions.

The D&D of nuclear facilities will generate a large volume of pipes, structural beams, and columns that are potentially contaminated. While some are indeed heavily contaminated and are best treated as radioactive waste in the traditional manner, many of these are likely to be clean. The problem is to economically prove that they are clean. Due to the nature of these items, traditional survey techniques involving manually checking all surfaces areas with a hand probe are impossible and/or quite expensive. Since these objects have been installed, used, and removed from operation, they have irregular shapes, are covered with paint or other debris, have protrusions, and have inaccessible inner surfaces. These characteristics all make alpha/beta assay very difficult. Canberra Industries has designed, manufactured, and tested the Mobile Internal/External Pipe Assessment System under a contract with FIU-HCET under the FETC/DOE program. The system has several unique features. Gamma detectors are used, since gamma rays are not easily absorbed. For most situations, we can now assay the inner surface of pipes, or the hidden surfaces inside welds, behind rivets or bolts, or under paint. Quantitative spectroscopy is used to identify nuclides and compare their activity to the appropriate limit. Germanium detectors are used to make accurate identification of the nuclides. Multiple Ge detectors [4] and large detectors [8cm diameter] are used for maximum sensitivity and good performance for all contamination locations. Mathematical calculations via Canberra's ISOCS software are used to develop specific energy-efficiency calibrations for each type and size of pipe or structural element.

The paper presents the results of a synthesis of current data on various concepts for the disposal of radioactive waste (RW) in deep geological formations and information on the implementation of RW deep borehole disposal (DBD) options. It identifies their features, advantages and disadvantages in terms of operational and long-term safety. The obtained results allowed us to draw the following conclusions. The geological environment of Ukraine allows the use of DBD concept in crystalline rocks overlain by sediments for the disposal of spent nuclear fuel, high level wastes and part of intermediate level wastes (fuel-containing materials and graphite) at a depths of 2-5 km. Sites near all NPPs and in the vicinity of the ChNPP can be selected as repository sites in crystalline rocks. Another promising option in Ukraine is deep borehole disposal in the salt domes. To make a decision on the applicability of the DBD concept, it is necessary to consider the cost, time factor and projected RW inventory.

I have adapted the nuclear materials storage location to align with mudstone bedrock for either or both above or below sea level tunnels.

Please find a revised scheme to locate a nuclear material storage scheme in mudstone bedrock with the option for both above and below sea level tunnels.

A trial proving tunnel is included to enable characterization to be determined to address risks and experiences tunnelling in the area.

It has significant capacity and can be constructed in stages.
Cumbria Nuclear Material Storage Scheme Constructed in Mudstone Bedrock Proposal
Considering the UK Government has a preference for installing the Nuclear Material Storage tunnels in Mudstone Bedrock the following location is an alternative to locating the work site further from Millom.  The selected area enables the tunnels to be either above sea level or below sea level.  The proposed scheme provides both above and below sea level tunnels to be constructed for the different performances to be assessed.
Each level within the mudstone material area can accommodate up to 11 tunnels each 60 metres apart.  This will enable up to 100 Km of tunnel per level.
The location is suitable for locating a jetty for import of TBMs and materials and export of removed crushed bedrock.
The proposed scheme includes a proving tunnel to enable the characteristics of the sites to be evaluated.  This tunnel will be used to test the logistics, storage methods and trial the equipment and machines required for operating the storage facilities.
The providing tunnel will enable the ground and bedrock and below sea level water movement characteristics and management to be evaluated.
The following images are:
Image 1 Image 1 Proposed Scheme location enabling the construction of on land and offshore tunnels in Mudstone
Image 2 Location of Portals and Storage Footprint
Image 3 Proposed 250m Contour Area
Image 4 Black Combe and Fell Grey Mudstone Area

Rutile, although not a major component of detrital heavy mineral deposits, is a valuable source of titanium oxide. Theoretically rutile is pure titanium dioxide (Ti02) and should form white or colourless tetragonal crystals with a density of 4.25gm/ml. However, natural rutile although tetragonal, displays a variety of colours ranging from red through brown to black, yellow or blue, variable density between 4.23 to 5.50g/ml as well as a range in the magnetic susceptibility and electrical conductivity. In addition to these variations exhibited by natural rutile, samples from detrital heavy mineral deposits normally contain, in addition to homogenous grains, composite grains, in which rutile is intergrown with one or more mineral species, commonly quartz, feldspar and ilmenite. The Sibaya Formation, like most detrital heavy mineral deposits, has a polymictic source, and as such contains rutile grains formed in many different chemical environments. Homogenous rutile grains display a chemical variation with a preference for the select few elements, which are compatible with the rutile cyrstallographic structure. The ions that substitute for titanium (Ti 4 +) in the crystal lattice are a reflection of chemical environment in which the crystal formed. The size and charge of the Ti 4 + ion greatly restricts the species that may enter the rutile crystal lattice, with Sb 3