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Reliability of instrumentation in a simulated nuclear-waste repository environment

Description: In light of the observed performance of the geotechnical instrumentation deployed on the Spent Fuel Test-Climax (SFT-C), the following conclusions and recommendations are offered. Further research is required to fully understand the observed failures of linear potentiometers utilized in sealed or partially ventilated extensometer head assemblies. Based on our field observations, we recommend deploying Schaevitz LVDTs or proximeters as extensometer transducers where a sealed head assembly is required. The user must be cognizant of the potential drift and thermal instabilities of these units, however. The first-generation wire extensometers and fracture monitors developed for this test are an accurate, reliable means for measuring convergence and discrete joint motion, respectively. The improved hermetically sealed vibrating-wire stressmeters function reliably. Calibration of the gauge remains difficult and further work is warranted in this area. Utilization of a single lot of sheathed thermocouples in a zone box configuration is a cost-effective, accurate, and reliable means of measuring temperatures in the repository environment. Care must be taken to tailor the sheath composition to the test thermal and chemical environment. Monitoring and post-test studies will continue at the SFT-C through 1984. Included in these studies will be post-test calibrations of all accessible instrumentation. A final report on the performance of the field instrumentation will be prepared at that time.
Date: June 1, 1983
Creator: Patrick, W.C. & Rector, N.L.
Partner: UNT Libraries Government Documents Department

Geologic disposal of radioactive waste, 1983

Description: Geologic repositories for radioactive waste are evolving from conceptualization to the development of specific designs. Estimates of long-term hazards must be based upon quantitative predictions of environmental releases over time periods of hundreds of thousands of years and longer. This paper summarizes new techniques for predicting the long-term performance of repositories, it presents estimates of future environmental releases and radiation doses that may result for conceptual repositories in various geologic media, and it compares these predictions with an individual dose criterion of 10{sup -4} Sv/y. 50 references, 11 figures, 6 tables.
Date: October 1, 1983
Creator: Pigford, T.H.
Partner: UNT Libraries Government Documents Department

Thermal modeling of nuclear waste package designs for disposal in tuff

Description: Lawrence Livermore National Laboratory is involved in the design and testing of high-level nuclear waste packages. Many of the aspects of waste package design and testing (e.g., corrosion and leaching) depend in part on the temperature history of the emplaced packages. This paper discusses thermal modeling and analysis of various emplaced waste package conceptual designs including the models used, the assumptions and approximations made, and the results obtained. 6 references, 6 figures, 3 tables.
Date: September 1, 1983
Creator: Hockman, J.N. & O`Neal, W.C.
Partner: UNT Libraries Government Documents Department

Studies of altered vitrophyre for the prediction of nuclear waste repository - induced thermal alteration at Yucca Mountain, Nevada

Description: Nuclear waste emplacement in devitrified volcanic tuff at Yucca Mountain will raise the temperature of surrounding rock for a geologically significant period of time. This study evaluates the susceptibility of an underlying 50-ft-thick vitrophyre to thermal alteration by examining alteration that occured in the rock as it cooled after deposition. A 10{sup 0}C temperature rise should have no mineralogical effects on the vitrophyre, but an increase of 60{sup 0} or more is likely to result in alteration. Expected mineralogic changes in the vitrophyre caused by this amount of thermal loading include crystallization of zeolites and smectite. Alteration will be concentrated of zeolites and smectite. Alteration will be concentrated in a thin interval near the top of the vitrophyre and along fractures. Adsorbed water and water in preexisting hydrous minerals and in glass may contribute to hydrothermal alteration of underlying vitrophyre. Bulk porosity change would be slight and local porosity increase would probably be restricted to the upper part of the vitrophyre. Although some fracture filling could occur, such a minor sealing effect would be balanced by development of secondary porosity. Zeolites and smectite, newly-crystallized along fluid flow paths below the waste repository, could provide an enhanced sorptive barrier to radionuclide migration. 21 references, 3 figures.
Date: December 31, 1983
Creator: Levy, S.S.
Partner: UNT Libraries Government Documents Department

Impacts of transportation on a test and evaluation facility for nuclear waste disposal: a systems analysis

Description: An essential element of the Test and Evaluation Facility (TEF) is a waste packaging facility capable of producing a small number Test and Evaluation Facility of packages consisting of several different waste forms. The study envisions three scenarios for such a packaging facility: (1) modify an existing hot cell facility such as the Engine Maintenance Assembly and Disassembly (EMAD) facility at the Nevada Test Site so that it can serve as a packaging facility for the TEF. This scenario is referred to as the EMAD Option. (2) Build a new generic packaging facility (GPF) at the site of the TEF. In other words, colocate the GPF and the TEF. This scenario is referred to as the GPF Option, and (3) utilize the EMAD facility in conjunction with a colocated GPF (of minimal size and scope) at the TEF. This scenario is referred to as the Split Option. The results of the system study clearly bring out the fact that transportation has a significant impact on the selection and siting of the waste packaging facility. Preliminary conclusions, subject to the assumptions of the study, include the following: (1) regardless of the waste form, the GPF option is preferable to the other two in minimizing both transportation costs and logistical problems, (2) for any given scenario and choice of waste forms, there exists a candidate TEF location for which the transportation costs are at a minimum compared to the other locations, (3) in spite of the increased transportation costs and logistical complexity, the study shows that the overall system costs favor modification of an existing hot cell facility for the particular case considered.
Date: 1983
Creator: Varadarajan, R. V.; Peterson, R. W.; Joy, D. S. & Gibson, S. M.
Partner: UNT Libraries Government Documents Department

TOUGH: a numerical model for nonisothermal unsaturated flow to study waste canister heating effects

Description: The physical processes modeled and the mathematical and numerical methods employed in a simulator for non-isothermal flow of water, vapor, and air in permeable media are briefly summarized. The simulator has been applied to study thermo-hydrological conditions in the near vicinity of high-level nuclear waste packages emplaced in unsaturated rocks. The studies reported here specifically address the question whether or not the waste canister environment will dry up in the thermal phase. 13 references, 8 figures, 2 tables.
Date: December 1, 1983
Creator: Pruess, K. & Wang, J.S.Y.
Partner: UNT Libraries Government Documents Department

Waste package for a repository located in tuff

Description: The development of waste packages for emplacement in a tuff repository has been proceeding during the past year on a broad front. Experimental work has been focused on determination of important package environment parameters and testing the response of waste forms and package materials to the anticipated environment. Conceptual designs have been selected with alternatives to accommodate present uncertainties in the environment and material performance. Computational capabilities are being adapted to provide analyses of anticipated package performance, and plans are being developed for in-situ testing. The waste package activities have been integrated into the overall NNWSI project to assure timely completion consistent with the statutory and regulatory requirements leading to repository site selection around the end of the decade. 7 references.
Date: November 1, 1983
Creator: Ballou, L.B.
Partner: UNT Libraries Government Documents Department

Numerical simulation of flow and transport in partially saturated, fractured tuff

Description: The unsaturated, fractured tuff of Yucca Mountain in the Nevada Test Site is one of the target sites for geologic storage of high-level radioactive waste. A modeling study of flow and transport in this geologically complex site is presented. Numerical models of mass and heat flow in conjunction with analytical solutions are being used for sensitivity and pathway analysis studies and to aid in design and interpretation of laboratory and field flow and transport tests in tuff. 11 references, 9 figures, 1 table.
Date: December 31, 1983
Creator: Travis, B.J.; Hodson, S.W.; Cook, T.L.; Nuttall, H.E. & Rundberg, R.
Partner: UNT Libraries Government Documents Department

Handling encapsulated spent fuel in a geologic repository environment

Description: In support of the Spent Fuel Test-Climate at the U.S. Department of Energy`s Nevada Test Site, a spent-fuel canister handling system has been designed, deployed, and operated successfully during the past five years. This system transports encapsulated commercial spent-fuel assemblies between the packaging facility and the test site ({similar_to}100 km), transfers the canisters 420 m vertically to and from a geologic storage drift, and emplaces or retrieves the canisters from the storage holes in the floor of the drift. The spent-fuel canisters are maintained in a fully shielded configuration at all times during the handling cycle, permitting manned access at any time for response to any abnormal conditions. All normal operations are conducted by remote control, thus assuring as low as reasonably achievable exposures to operators; specifically, we have had no measurable exposure during 30 canister transfer operations. While not intended to be prototypical of repository handling operations, the system embodies a number of concepts, now demonstrated to be safe, reliable, and economical, which may be very useful in evaluating full-scale repository handling alternatives in the future. Among the potentially significant concepts are: Use of an integral shielding plug to minimize radiation streaming at all transfer interfaces. Hydraulically actuated transfer cask jacking and rotation features to reduce excavation headroom requirements. Use of a dedicated small diameter (0.5 m) drilled shaft for transfer between the surface and repository workings. A wire-line hoisting system with positive emergency braking device which travels with the load. Remotely activated grapples - three used in the system - which are insensitive to load orientation. Rail-mounted underground transfer vehicle operated with no personnel underground.
Date: February 1, 1983
Creator: Ballou, L.B.
Partner: UNT Libraries Government Documents Department

A Pyrovidicon-based Inspection System for Nuclear Reactor Safety

Description: At the Savannah River Nuclear Facility irradiated assemblies are conveyed through the air from the reactor to a discharge/entry channel, where they are immersed in water. This paper addresses the monitoring of the temperature of these assemblies while they are in transit during the discharge cycle. To accomplish this, a remotely controlled and monitored radiation-hardened thermal imaging and alarm system was installed at each reactor. The paper will discuss the system concept and operation. The program for radiation hardening and testing this equipment will be reviewed.
Date: October 12, 1983
Creator: Lynam, E.C.
Partner: UNT Libraries Government Documents Department

Economics of mined geologic repositories

Description: During 1982, Congress considered legislation to provide for the development of repositories for the disposal of high-level radioactive waste and spent nuclear fuel. The result of this legislative effort was the Nuclear Waste Policy Act of 1982 (NWPA), PL 97-425, signed into law January 7, 1983. An important part of the NWPA was the establishment of special funds in the US Treasury for Waste Disposal and Interim Storage to be financed by user fees to pay for all costs of the program. An initial fee of 1.0 mill per kilowatt-hour was specified. The Secretary was asked to annually review the amount of the fees established... to evaluate whether collection of the fee will provide sufficient revenues to offset the costs... In the event of a prospective fee cost mismatch, the Secretary was asked to propose an adjustment to the fee to insure full cost recovery. A series of studies were sponsored by DOE in 1982 to estimate program costs, to calculate the necessary fees to assure cost recovery, and to address uncertainties that could affect future program costs and consequent fee schedules. A brief summary of the 1982 cost estimates is presented. Sources of key cost uncertainties are discussed and the bases for the cost recovery fee calculations are summarized. 17 references, 2 figures, 3 tables.
Date: December 31, 1983
Creator: Hofmann, P.L. & Dippold, D.G.
Partner: UNT Libraries Government Documents Department

Surveys for desert tortoise on the proposed site of a high-level nuclear waste repository at the Nevada Test Site

Description: The National Waste Terminal Storage Program is a national search for suitable sites to isolate commercial spent nuclear fuel or high-level radioactive waste. The Nevada Nuclear Waste Storage Investigation (NNWSI) managed by the U.S. Department of Energy (DOE), Nevada Operations Office, was initiated to study the suitability of a portion of Yucca Mountain on the DOE`s Nevada Test Site (NTS) as a location for such a repository. EG and G was contracted to provide information concerning the ecosystems encountered on the site. A comprehensive literature survey was conducted to evaluate the status and completeness of the existing biological information for the previously undisturbed area. Site specific studies were begun in 1981 when preliminary field surveys confirmed the presence of the desert tortoise (Gopherus agassizi) within the project area FY82 studies were designed to determine the overall distribution and abundance of the tortoise within the area likely to be impacted by NNWSI activities. The Yucca Mountain area of the Nevada Test Site is situated close to the northern range limit of the desert tortoise. Prior to the 1982 surveys, the desert tortoise was reported from only nine locations on NTS. A known population had been under study in Rock Valley about 25 miles southeast of the project area. However, the distribution and population densities of tortoise in the southwest portion of NTS were virtually unknown. Results of our surveys indicate that desert tortoise can be expected, albeit in small numbers, in a wide range of Mojavean and Transitional habitats.
Date: December 31, 1983
Creator: Collins, E.; Sauls, M.L. & O`Farrell, T.P.
Partner: UNT Libraries Government Documents Department

Design of a nuclear-waste package for emplacement in tuff

Description: Design, modeling, and testing activities are under way at LLNL in the development of high level nuclear waste package designs. We discuss the geological characteristics affecting design, the 10CFR60 design requirements, conceptual designs, metals for containment barriers, economic analysis, thermal modeling, and performance modeling.
Date: February 1983
Creator: O`Neal, W. C.; Rothman, A. J.; Gregg, D. W.; Hockman, J. N.; Revelli, M. A.; Russell, E. W. et al.
Partner: UNT Libraries Government Documents Department

Selection of barrier metals for a waste package in tuff

Description: The Nevada Nuclear Waste Storage Investigations (NNWSI) project under the Civilian Radioactive Waste Management Program is planning a repository at Yucca Mountain at the Nevada Test Site for isolation of high-level nuclear waste. Lawrence Livermore National Laboratory is developing designs for an engineered barrier system containing several barriers such as the waste form, a canister and/or an overpack, packing, and near field host rock. In this paper we address the selection of metal containment barriers. 13 references, 4 tables.
Date: October 1, 1983
Creator: Russell, E.W.; McCright, R.D. & O`Neal, W.C.
Partner: UNT Libraries Government Documents Department

NNWSI waste form testing program

Description: A waste form testing program has been developed to ensure that the release rate of radionuclides from the engineered barrier system will meet NRC and EPA regulatory requirements. Waste form performance testing will be done under unsaturated, low water availability conditions which represent the expected repository conditions. Testing will also be done under conditions of total immersion of the waste form in repository-type water to cover the possibility that localized portions of the repository might contain standing water. Testing of reprocesses waste forms for CHLW and DHLW will use reaction vessels fabricated from Topopah Spring tuff. Chemical elements which are expected to show the highest release rates in the mildly oxidizing environment of the Topopah Spring tuff horizon at Yucca Mountain are Np and Tc. To determine the effect of residual canister material and of corrosion products from the canister/overpack, waste form testing will be done in the presence of these materials. The release rate of all radionuclides which are subject to NRC and EPA regulations will be measured, and the interactive effects of the released radionuclide and the rock reaction vessels will be determined. The testing program for spent fuel will determine the release rate from bare spent fuel pellets and from Zircaloy clad spent fuel where the cladding contains minor defects. A metal testing program for Zircaloy will establish the expected lifetime of the cladding material. Estimation of the state of cladding for fuel presently in reactor pool storage will provide baseline data for Zircaloy containment credit. 9 references, 4 figures.
Date: November 1, 1983
Creator: Oversby, V.M.
Partner: UNT Libraries Government Documents Department

Costs and impacts of transporting nuclear waste to candidate repository sites

Description: In this paper, a status report on the current estimated costs and impacts of transporting high-level nuclear wastes to candidate disposal sites is given. Impacts in this analysis are measured in terms of risk to public health and safety. Since it is difficult to project the status of the nuclear industry to the time of repository operation - 20 to 50 years in the future - particular emphasis in the paper is placed on the evaluation of uncertainties. The first part of this paper briefly describes the characteristics of the waste that must be transported to a high-level waste disposal site. This discussion is followed by a section describing the characteristics of the waste transport system. Subsequent sections describe the costs and risk assessments of waste transport. Finally, in a concluding section, the effect of the uncertainties in the definition of the waste disposal system on cost and risk levels is evaluated. This last section also provides some perspectives on the magnitude of the cost and risk levels relative to other comparable costs and risks generally encountered. 13 references, 2 figures, 16 tables.
Date: December 31, 1983
Creator: McSweeney, T.I.; Peterson, R.W. & Gupta, R.
Partner: UNT Libraries Government Documents Department

Evaluation of DOE radionuclide solubility data and selected retardation parameters: description of calculational and confirmatory experimental activities

Description: An experimentally oriented program has been initiated to support the NRC analysis and licensing activities related to high-level nuclear waste repositories. The program will allow the NRC to independently confirm key geochemical values used in the site performance assessments submitted by the DOE candidate repository site projects. Key radionuclide retardation factor values, particularly radionuclide solubility and sorption values under site specific geochemical conditions, are being confirmed. The initial efforts are being directed toward basalt rock/groundwater systems relevant to the BWIP candidate site in the Pasco Basin. Future work will consider tuff (NNWSI candidate site in Yucca Mountain) and salt (unspecified ONWI bedded or domal salt sites) rock/groundwater systems. Initial experimental results with technetium have confirmed the BWIP values for basalt/groundwater systems under oxic redox conditions: high solubility and no sorption. Under reducing redox conditions, however, the experimental work did not confirm the proposed technetium values recommended by BWIP. In the presence of hydrazine to establish reducing conditions, an apparent solubility limit for technetium of about 5E-7 mol/L was encountered; BWIP recommended calculated values of 1E-12 or greater than or equal to 1E-14 mol/L. Experimental evidence concerning sorption of reduced technetium species is incomplete at this time. Equilibrium speciation and saturation indices were calculated for well water data sets from BWIP using the computer code PHREEQUE. Oversaturation was indicated for hematite and quartz in all data sets. Near surface samples were undersaturated with respect to calcite, but most deep samples were oversaturated with respect to calcite and other carbonate minerals.
Date: December 31, 1983
Creator: Kelmers, A.D.; Clark, R.J.; Cutshall, N.H.; Johnson, J.S. & Kessler, J.H.
Partner: UNT Libraries Government Documents Department

Disproportionation and polymerization of plutonium(IV) in dilute aqueous solutions

Description: The rates of polymerization and disproportionation of Pu(IV) have been studied using low concentrations: (1.7 - 10) x 10{sup -}M Pu, (0.8 - 12) x 10{sup -}M HCl and 0.0iM ionic strength. Osmium(II) complexes such as the tris-4,4`-2,2`-bipyridine complex were found to react rapidly with Pu(IV) but very slowly, if at all, with Pu(IV) polymer, Pu(III), or Pu(V). Thus, it is possible to determine unreacted Pu(IV) in the presence of rection products by using Os(II) complexes. Disproportionation reaction products, Pu(III) and Pu(V), were determined using their reactions with Ce(IV) sulfate. We find -d[Pu(IV)]/dt = k`[Pu(IV)]{sup 2} at constant pH. Log k` varies from about 4.25 at pH 3 to about 7.0 at pH 4.1 (units for k` are M{sup -1}min{sup -1}). The [H{sup +}] dependence varies from about -2 to -3 over the pH range studied. The measured rate is the sum of those for polymerization and disproportionation; the latter reaction amounts to about 75% of the total at pH 3 and 20% at pH 4. The second-order rate constants for disproportionation are very much larger than expected on the basis of extrapolation from 0.2 to 1.0M HC10{sub 4} solutions. The products of the reaction do not affect the rate, but U(VI), aged Pu(IV) polymer, and CO{sub 2} increase the rate.
Date: December 31, 1983
Creator: Newton, T.W. & Rundberg, V.L.
Partner: UNT Libraries Government Documents Department

Selection of barrier metals for a waste package in tuff

Description: The Nevada Nuclear Waste Storage Investigation (NNWSI) project under the Civilian Radioactive Waste Management Program is planning a repository at Yucca Mountain at the Nevada Test Site for isolation of high-level nuclear waste. LLNL is developing designs for an engineered barrier system containing several barriers such as the waste form, a canister and/or an overpack, packing, and near field host rock. The selection of metal containment barriers is addressed. 13 references.
Date: September 1, 1983
Creator: Russell, E.W.; McCright, R.D. & O`Neal, W.C.
Partner: UNT Libraries Government Documents Department