Thermal effects of electrically conductive deposits in melter

International Nuclear Information System (INIS)

Choi, I.G.; Bickford, D.F.; Carter, J.T.

1992-01-01

The radioactive waste processed by the Defense Waste Processing Facility melter at the Savannah river Site contains noble metal fission-products. Operation of waste-glass melters treating commercial power reactor wastes indicates that accumulation of noble metals on melter floors can lead to distortion of electric heating patterns, loss of power, and possible electrode damage. Changes in melter geometry have been developed in Japan and Germany to minimize these effects. The two existing melters for the US Department of Energy's Defense Waste Processing Facility were designed in 1982, before this effect was known or had been characterized. Modeling and pilot scale tests are being conducted in the Integrated DWPF melter system to determine if the effect is significant for melters processing defense wastes, and if the effect can be diagnosed and corrected without significant damage or changes to the melter design. This document provides a discussion of these tests

Physical and numerical modeling of Joule-heated melters

Energy Technology Data Exchange (ETDEWEB)

Eyler, L.L.; Skarda, R.J.; Crowder, R.S. III; Trent, D.S.; Reid, C.R.; Lessor, D.L.

1985-10-01

The Joule-heated ceramic-lined melter is an integral part of the high level waste immobilization process under development by the US Department of Energy. Scaleup and design of this waste glass melting furnace requires an understanding of the relationships between melting cavity design parameters and the furnace performance characteristics such as mixing, heat transfer, and electrical requirements. Developing empirical models of these relationships through actual melter testing with numerous designs would be a very costly and time consuming task. Additionally, the Pacific Northwest Laboratory (PNL) has been developing numerical models that simulate a Joule-heated melter for analyzing melter performance. This report documents the method used and results of this modeling effort. Numerical modeling results are compared with the more conventional, physical modeling results to validate the approach. Also included are the results of numerically simulating an operating research melter at PNL. Physical Joule-heated melters modeling results used for qualiying the simulation capabilities of the melter code included: (1) a melter with a single pair of electrodes and (2) a melter with a dual pair (two pairs) of electrodes. The physical model of the melter having two electrode pairs utilized a configuration with primary and secondary electrodes. The principal melter parameters (the ratio of power applied to each electrode pair, modeling fluid depth, electrode spacing) were varied in nine tests of the physical model during FY85. Code predictions were made for five of these tests. Voltage drops, temperature field data, and electric field data varied in their agreement with the physical modeling results, but in general were judged acceptable. 14 refs., 79 figs., 17 tabs.

Physical and numerical modeling of Joule-heated melters

International Nuclear Information System (INIS)

Eyler, L.L.; Skarda, R.J.; Crowder, R.S. III; Trent, D.S.; Reid, C.R.; Lessor, D.L.

1985-10-01

The Joule-heated ceramic-lined melter is an integral part of the high level waste immobilization process under development by the US Department of Energy. Scaleup and design of this waste glass melting furnace requires an understanding of the relationships between melting cavity design parameters and the furnace performance characteristics such as mixing, heat transfer, and electrical requirements. Developing empirical models of these relationships through actual melter testing with numerous designs would be a very costly and time consuming task. Additionally, the Pacific Northwest Laboratory (PNL) has been developing numerical models that simulate a Joule-heated melter for analyzing melter performance. This report documents the method used and results of this modeling effort. Numerical modeling results are compared with the more conventional, physical modeling results to validate the approach. Also included are the results of numerically simulating an operating research melter at PNL. Physical Joule-heated melters modeling results used for qualiying the simulation capabilities of the melter code included: (1) a melter with a single pair of electrodes and (2) a melter with a dual pair (two pairs) of electrodes. The physical model of the melter having two electrode pairs utilized a configuration with primary and secondary electrodes. The principal melter parameters (the ratio of power applied to each electrode pair, modeling fluid depth, electrode spacing) were varied in nine tests of the physical model during FY85. Code predictions were made for five of these tests. Voltage drops, temperature field data, and electric field data varied in their agreement with the physical modeling results, but in general were judged acceptable. 14 refs., 79 figs., 17 tabs

Program plan: DWPF/HLWDP stirred Melter Program Plan

International Nuclear Information System (INIS)

Smith, M.E.

1994-01-01

Slurry Fed Melters (SFM) have been developed in the United States, Europe, and Japan for the conversion of high-level radioactive waste (HLW) to borosilicate glass for permanent disposal. The newest design, the stirred melter, combines the high production rates and high glass quality features of the Joule-heated melters with the low-cost, compact, simple maintenance features of the pot melters. However, further engineering design and demonstrations are needed to operate the stirred melter on a large scale. This document outlines the program which develops a full scale stirred melter for the DWPF (240 pph), and provides a basis which will allow further scale-up of the technology for use in the Hanford High Level Waste Disposal Program (HLWDP) for up to four times the reference capacity

Control of high level radioactive waste-glass melters

International Nuclear Information System (INIS)

Bickford, D.F.; Choi, A.S.

1991-01-01

Slurry Fed Melters (SFM) are being developed in the United States, Europe and Japan for the conversion of high-level radioactive waste to borosilicate glass for permanent disposal. The high transition metal, noble metal, nitrate, organic, and sulfate contents of these wastes lead to unique melter redox control requirements. Pilot waste-glass melter operations have indicated the possibility of nickel sulfide or noble-metal fission-product accumulation on melter floors, which can lead to distortion of electric heating patterns, and decrease melter life. Sulfide formation is prevented by control of the redox chemistry of the melter feed. The redox state of waste-glass melters is determined by balance between the reducing potential of organic compounds in the feed, and the oxidizing potential of gases above the melt, and nitrates and polyvalent elements in the waste. Semiquantitative models predicting limitations of organic content have been developed based on crucible testing. Computerized thermodynamic computations are being developed to predict the sequence and products of redox reactions and is assessing process variations. Continuous melter test results have been compared to improved computer staged-thermodynamic-models of redox behavior. Feed chemistry control to prevent sulfide and moderate noble metal accumulations are discussed. 17 refs., 3 figs

Evaluation of liquid-fed ceramic melter scale-up correlations

International Nuclear Information System (INIS)

Koegler, S.S.; Mitchell, S.J.

1988-08-01

This study was conducted to determine the parameters governing factors of scale for liquid-fed ceramic melters (LFCMs) in order to design full-scale melters using smaller-scale melter data. Results of melter experiments conducted at Pacific Northwest Laboratory (PNL) and Savannah River Laboratory (SRL) are presented for two feed compositions and five different liquid-fed ceramic melters. The melter performance data including nominal feed rate and glass melt rate are correlated as a function of melter surface area. Comparisons are made between the actual melt rate data and melt rates predicted by a cold cap heat transfer model. The heat transfer model could be used in scale-up calculations, but insufficient data are available on the cold cap characteristics. Experiments specifically designed to determine heat transfer parameters are needed to further develop the model. 17 refs

Preliminary evaluation of PSCM and BIPP melter design and operating conditions using physical modeling

International Nuclear Information System (INIS)

Skarda, R.J.; Hauser, S.G.; Fort, J.A.

1985-05-01

The Glass Melter Physical Modeling investigation was initiated to support Pacific Northwest Laboratory (PNL) Hanford Waste Vitrification Program. Specifically, results discussed herein are those of the modeled B-Plant Immobilization Pilot Plant (BIPP) and Pilot Scale Ceramic Melter (PSCM) designs. The purpose of this study was to evaluate various melter design features using laboratory scale models. Hydrodynamic, thermal, and electrical similarity between the modeling fluid and the molten glass were primary objectives. Stroboscopic velocity measurements (flow visualization), temperature measurements, and electrical potential measurements were used to investigate the molten glass behavior. Results from this effort are to provide input to melter design and proposed operation in addition to providing a data base for verifying numerical models. 13 refs., 48 figs., 24 tabs

DC plasma arc melter technology for waste vitrification

International Nuclear Information System (INIS)

Hamilton, R.A.; Wittle, J.K.; Trescot, J.

1995-01-01

This paper describes the features and benefits of a breakthrough DC Arc Melter for the permanent treatment of all types of solid wastes including nonhazardous, hazardous and radioactive. This DC Arc Furnace system, now commercially available, is the low cost permanent solution for solid waste pollution prevention and remediation. Concern over the effective disposal of wastes generated by the industrial society, worldwide, has prompted development of technologies to address the problem. For the most part these technologies have resulted in niche solutions with limited application. The only solution that has the ability to process almost all wastes, and to recover/recycle metallic and inorganic matter, is the group of technologies known as melters. Melters have distinct advantages over traditional technologies such as incineration because melters operate at higher temperatures, are relatively unaffected by changes in the waste stream, produce a vitrified stable product, and have the capability to recover/recycle slag, metals and gas. The system, DC Plasma Arc Melter, has the lowest capital, maintenance and operating cost of any melter technology because of its patented DC Plasma Arc with graphite electrode. DC Plasma Arc Melter systems are commercially available in sizes from 50 kg/batch or 250--3,000 kg/hr on a continuous feed basis. This paper examines the design and operating benefits of a DC Plasma Arc Melter System

Comparing flow-through and static ice cave models for Shoshone Ice Cave

Directory of Open Access Journals (Sweden)

Kaj E. Williams

2015-05-01

Full Text Available In this paper we suggest a new ice cave type: the “flow-through” ice cave. In a flow-through ice cave external winds blow into the cave and wet cave walls chill the incoming air to the wet-bulb temperature, thereby achieving extra cooling of the cave air. We have investigated an ice cave in Idaho, located in a lava tube that is reported to have airflow through porous wet end-walls and could therefore be a flow-through cave. We have instrumented the site and collected data for one year. In order to determine the actual ice cave type present at Shoshone, we have constructed numerical models for static and flow-through caves (dynamic is not relevant here. The models are driven with exterior measurements of air temperature, relative humidity and wind speed. The model output is interior air temperature and relative humidity. We then compare the output of both models to the measured interior air temperatures and relative humidity. While both the flow-through and static cave models are capable of preserving ice year-round (a net zero or positive ice mass balance, both models show very different cave air temperature and relative humidity output. We find the empirical data support a hybrid model of the static and flow-through models: permitting a static ice cave to have incoming air chilled to the wet-bulb temperature fits the data best for the Shoshone Ice Cave.

Control of radioactive waste-glass melters

International Nuclear Information System (INIS)

Bickford, D.F.; Smith, P.K.; Hrma, P.; Bowan, B.W.

1987-01-01

Radioactive waste-glass melters require physical control limits and redox control of glass to assure continuous operation, and maximize production rates. Typical waste-glass melter operating conditions, and waste-glass chemical reaction paths are discussed. Glass composition, batching and melter temperature control are used to avoid the information of phases which are disruptive to melting or reduce melter life. The necessity and probable limitations of control for electric melters with complex waste feed compositions are discussed. Preliminary control limits, their bases, and alternative control methods are described for use in the Defense Waste Processing Facility (DWPF) at the US Department of Energy's Savannah River Plant (SRP), and at the West Valley Demonstration Project (WVDP). Slurries of simulated high level radioactive waste and ground glass frit or glass formers have been isothermally reacted and analyzed to identify the sequence of the major chemical reactions in waste vitrification, and their effect on waste-glass production rates. Relatively high melting rates of waste batches containing mixtures of reducing agents (formic acid, sucrose) and nitrates are attributable to exothermic reactions which occur at critical stages in the vitrification process. The effect of foaming on waste glass production rates is analyzed, and limits defined for existing waste-glass melters, based upon measurable thermophysical properties. Through balancing the high nitrate wastes of the WVDP with reducing agents, the high glass melting rates and sustained melting without foaming required for successful WVDP operations have been demonstrated. 65 refs., 4 figs., 15 tabs

Application of electrical resistance tomography to glass melter

International Nuclear Information System (INIS)

Ichijo, Noriaki; Sakai, Taiji; Fujiwara, Hiroaki; Matsuno, Shinsuke; Misumi, Ryuta; Nishi, Kazuhiko; Kaminoyama, Meguru

2015-01-01

This paper describes the application of electrical resistance tomography (ERT) to glass melter to monitor the accumulation of the noble metals. To minimize the modification of the melter, existing structures such as thermowells and heating electrodes are used as electrodes of ERT, and the number of electrodes is much fewer than the conventional method. Therefore, Expanding Combination Data Acquisition method (ECDA) is developed and applies to the glass melter. ECDA method uses adjacent method and opposite method as a data acquisition and current injection electrodes are used as voltage measurement electrodes to increase the number of the data. In addition, conductivity images are reconstructed only near the wall to improve the resolution. As a result of applying to the glass melter, the conductivity change inside the melter caused by temperature can be monitored. Furthermore, lower voltage is measured in case of containing the noble metals inside the melter. Therefore, the potential as a monitoring method be confirmed. (author)

DC graphite plasma arc melter technology for waste vitrification

International Nuclear Information System (INIS)

Hamilton, R.A.; Wittle, J.K.; Trescot, J.; Wilver, P.

1995-01-01

This paper describes the features and benefits of a DC Arc Melter for the permanent treatment of all types of solid wastes including nonhazardous, hazardous and radioactive. This DC Arc Melter system is the low cost permanent solution for solid waste pollution prevention and remediation. Concern over the effective disposal of wastes generated by our industrial society, worldwide, has prompted development of technologies to address the problem. The only solution that has the ability to process almost all wastes, and to recover/recycle metallic and inorganic matter, is the group of technologies known as melters. Melters have distinct advantages over traditional technologies such as incineration because melters; operate at higher temperatures, are relatively unaffected by changes in the waste stream, produce a vitrified stable product, reduce gaseous emissions, and have the capability to recover/recycle slag, metals and gas. The system, DC Plasma Arc Melter, has the lowest capital, maintenance and operating cost of any melter technology because of its patented DC Plasma Arc with graphite electrode. DC Plasma Arc Melter systems are available in sizes from 50 kg/batch or 250-3,000 kg/hr on a continuous basis

DWPF Glass Melter Technology Manual: Volume 1

International Nuclear Information System (INIS)

Iverson, D.C.

1993-01-01

This document details information about the design of a glass melter to be used at the Defense Waste Processing Facility located at the Savannah River Site. Topics include: melter overview, design basis, materials, vessel configuration, insulation, refractory configuration, electrical isolation, electrodes, riser and pour spout heater design, dome heaters, feed tubes, drain valves, differential pressure pouring, and melter test results. Information is conveyed using many diagrams and photographs

Off-gas chemistry study of melter feed by Springborn Laboratories

International Nuclear Information System (INIS)

Crow, K.R.

1985-01-01

The purpose of the off-gas chemistry study of melter feed samples was to support and help substantiate glass melter thermochemistry models developed for the DWPF. Both sludge-only and sludge-precipitate feed samples were analyzed. Each slurry sample was pyrolyzed at temperatures from 150 to 1000 0 C in air and inert atmospheres, and the head space products were analyzed by chromatographic and mass spectrometric methods. Thermogravimetric, differential scanning calorimetric and Fourier transform infrared analyses were also performed on each sample. There were no unusually high exothermic reactions that would be cause for concern in the DWPF melter. Results for two types of sludge-precipitate feed were compared. One type contained simulated precipitate hydrolysis aqueous (PHA) product as fed to the SCM-2 melter. The second type contained PHA from the lab-scale acid hydrolysis reactor in 677-T. A major difference between the two types was a small, but distinct, presence of higher aromatics in gas from feed with reactor-produced PHA. This feed also evolved more CO and CO 2 than feed with simulated PHA at high pyrolytic temperatures (>750 0 C). Recent analyses have identified the higher boiling aromatics in reactor-produced PHA as primarily diphenylamine and p-terphenyl. These compounds will be included in future PHA simulations that are fed to research melters. Under an inert atmosphere, benzene and phenol were the two most abundant organics evolved during pyrolysis of sludge-precipitate feed

Rheology enhancement for remediated PX6 melter feed

International Nuclear Information System (INIS)

Marek, J.C.; Eibling, R.E.

1996-01-01

This document is referenced in WSRC-TR-94-0556. This memorandum summarizes results of experimental work performed on the original IDMS PX6 melter feed, the remediated IDMS PX6 melter feed, and melter feeds produced in a laboratory simulation to duplicate the IDMS remediation as well as the experimental results on the caustic treatment to enhance the rheology. Characterization of the products of excess caustic addition and what steps to take if excess caustic is inadvertently added to the IDMS PX6 melter feed are also discussed

Crystallization In High Level Waste (HLW) Glass Melters: Operational Experience From The Savannah River Site

Energy Technology Data Exchange (ETDEWEB)

Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2014-02-27

processing strategy for the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The basis of this alternative approach is an empirical model predicting the crystal accumulation in the WTP glass discharge riser and melter bottom as a function of glass composition, time, and temperature. When coupled with an associated operating limit (e.g., the maximum tolerable thickness of an accumulated layer of crystals), this model could then be integrated into the process control algorithms to formulate crystal tolerant high level waste (HLW) glasses targeting higher waste loadings while still meeting process related limits and melter lifetime expectancies. This report provides a review of the scaled melter testing that was completed in support of the Defense Waste Processing Facility (DWPF) melter. Testing with scaled melters provided the data to define the DWPF operating limits to avoid bulk (volume) crystallization in the un-agitated DWPF melter and provided the data to distinguish between spinels generated by K-3 refractory corrosion versus spinels that precipitated from the HLW glass melt pool. This report includes a review of the crystallization observed with the scaled melters and the full scale DWPF melters (DWPF Melter 1 and DWPF Melter 2). Examples of actual DWPF melter attainment with Melter 2 are given. The intent is to provide an overview of lessons learned, including some example data, that can be used to advance the development and implementation of an empirical model and operating limit for crystal accumulation for WTP. Operation of the first and second (current) DWPF melters has demonstrated that the strategy of using a liquidus temperature predictive model combined with a 100 °C offset from the normal melter operating temperature of 1150 °C (i.e., the predicted liquidus temperature (TL) of the glass must be 1050 °C or less) has been successful in preventing any detrimental accumulation of spinel in the DWPF melt pool, and spinel has not been

Application of Ground Penetrating Radar Supported by Mineralogical-Geochemical Methods for Mapping Unroofed Cave Sediments

Directory of Open Access Journals (Sweden)

Teja Čeru

2018-04-01

locating areas of cave sediments at the surface and to determine their spatial extent, which is very important in delineating the geometry of unroofed cave systems. GPR thus proved to be a very valuable method in supporting geological and geomorphological mapping for a more comprehensive recognition of unroofed cave systems. These are important for understanding karstification and speleogenetic processes that influenced the formation of former underground caves and can help us reconstruct the direction of former underground water flows.

Conventional approaches for assessment of caving behaviour and support requirement with regard to strata control experiences in longwall workings

Directory of Open Access Journals (Sweden)

G.S.P. Singh

2015-06-01

Full Text Available Effective control of roof strata is very important for trouble free operation and regular face advance in mechanised longwall workings. It is now technically possible to exploit coal seams in difficult geo-mining conditions with the help of newer innovations in longwall face machineries. A reliable assessment of caving behaviour and support capacity requirement helps in selecting supports of adequate capacity and making operational preparedness for timely and confident solution of impending problems. This paper reviews the mechanism of roof caving and the conventional approaches of caving behaviour and support requirement in the context of major strata control experiences gained worldwide. The review shows that a number of approaches are being used for advance prediction of caving behaviour and support capacity requirement in a variety of geo-mining conditions. The theoretical explanation of the mechanism of roof caving and the design function of roof supports have been worked out through staged development of approaches, their evaluation followed by their gradual modification and enrichment of synthesized findings. This process is still continuing with consistently improved understanding through growing field experiences in the larger domain of geo-mining conditions and state-of-art strata analysis and monitoring techniques. These attempts have contributed significantly to improving the level of understanding and reducing the gap of uncertainty in planning and design of longwall operation in a given geo-mining condition.

Maximum total organic carbon limit for DWPF melter feed

International Nuclear Information System (INIS)

Choi, A.S.

1995-01-01

DWPF recently decided to control the potential flammability of melter off-gas by limiting the total carbon content in the melter feed and maintaining adequate conditions for combustion in the melter plenum. With this new strategy, all the LFL analyzers and associated interlocks and alarms were removed from both the primary and backup melter off-gas systems. Subsequently, D. Iverson of DWPF- T ampersand E requested that SRTC determine the maximum allowable total organic carbon (TOC) content in the melter feed which can be implemented as part of the Process Requirements for melter feed preparation (PR-S04). The maximum TOC limit thus determined in this study was about 24,000 ppm on an aqueous slurry basis. At the TOC levels below this, the peak concentration of combustible components in the quenched off-gas will not exceed 60 percent of the LFL during off-gas surges of magnitudes up to three times nominal, provided that the melter plenum temperature and the air purge rate to the BUFC are monitored and controlled above 650 degrees C and 220 lb/hr, respectively. Appropriate interlocks should discontinue the feeding when one or both of these conditions are not met. Both the magnitude and duration of an off-gas surge have a major impact on the maximum TOC limit, since they directly affect the melter plenum temperature and combustion. Although the data obtained during recent DWPF melter startup tests showed that the peak magnitude of a surge can be greater than three times nominal, the observed duration was considerably shorter, on the order of several seconds. The long surge duration assumed in this study has a greater impact on the plenum temperature than the peak magnitude, thus making the maximum TOC estimate conservative. Two models were used to make the necessary calculations to determine the TOC limit

Crystallization in high level waste (HLW) glass melters: Savannah River Site operational experience

Energy Technology Data Exchange (ETDEWEB)

Fox, Kevin M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Peeler, David K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Kruger, Albert A. [USDOE Office of River Protection, Richland, WA (United States)

2015-06-12

This paper provides a review of the scaled melter testing that was completed for design input to the Defense Waste Processing Facility (DWPF) melter. Testing with prototype melters provided the data to define the DWPF operating limits to avoid bulk (volume) crystallization in the un-agitated DWPF melter and provided the data to distinguish between spinels generated by refractory corrosion versus spinels that precipitated from the HLW glass melt pool. A review of the crystallization observed with the prototype melters and the full-scale DWPF melters (DWPF Melter 1 and DWPF Melter 2) is included. Examples of actual DWPF melter attainment with Melter 2 are given. The intent is to provide an overview of lessons learned, including some example data, that can be used to advance the development and implementation of an empirical model and operating limit for crystal accumulation for a waste treatment and immobilization plant.

Design and operation of small-scale glass melters for immobilizing radioactive waste

International Nuclear Information System (INIS)

Plodinec, M.J.; Chismar, P.H.

1980-01-01

A small-scale (3-kg), joule-heated, continuous melter has been designed to study vitrification of Savannah River Plant radioactive waste. The first melter built has been in nonradioactive service for nearly three years. This melter had Inconel 690 electrodes and uses Monofrax K-3 for the contact refractory. Several problems seem in this melter have had an impact on the design of a full-scale system. Problems include uncontrolled electric currents passing through the throat, and formation of a slag layer at the bottom of the melter. The performance of a similar melter in a low-maintenance, radioactive environment is also described. Problems such as halide refluxing, and hot streaking, first observed in this melter, are also discussed

Melter Throughput Enhancements for High-Iron HLW

Energy Technology Data Exchange (ETDEWEB)

Kruger, A. A. [Department of Energy, Office of River Protection, Richland, Washington (United States); Gan, Hoa [The Catholic University of America, Washington, DC (United States); Joseph, Innocent [The Catholic University of America, Washington, DC (United States); Pegg, Ian L. [The Catholic University of America, Washington, DC (United States); Matlack, Keith S. [The Catholic University of America, Washington, DC (United States); Chaudhuri, Malabika [The Catholic University of America, Washington, DC (United States); Kot, Wing [The Catholic University of America, Washington, DC (United States)

2012-12-26

This report describes work performed to develop and test new glass and feed formulations in order to increase glass melting rates in high waste loading glass formulations for HLW with high concentrations of iron. Testing was designed to identify glass and melter feed formulations that optimize waste loading and waste processing rate while meeting all processing and product quality requirements. The work included preparation and characterization of crucible melts to assess melt rate using a vertical gradient furnace system and to develop new formulations with enhanced melt rate. Testing evaluated the effects of waste loading on glass properties and the maximum waste loading that can be achieved. The results from crucible-scale testing supported subsequent DuraMelter 100 (DM100) tests designed to examine the effects of enhanced glass and feed formulations on waste processing rate and product quality. The DM100 was selected as the platform for these tests due to its extensive previous use in processing rate determination for various HLW streams and glass compositions.

Freeze and restart of the DWPF Scale Glass Melter

International Nuclear Information System (INIS)

Choi, A.S.

1989-01-01

After over two years of successful demonstration of many design and operating concepts of the DWPF Melter system, the last Scale Glass Melter campaign was initiated on 6/9/88 and consisted of two parts; (1) simulation of noble metal buildup and (2) freeze and subsequent restart of the melter under various scenarios. The objectives were to simulate a prolonged power loss to major heating elements and to examine the characteristics of transient melter operations during a startup with a limited supply of lid heat. Experimental results indicate that in case of a total power loss to the lower electrodes such as due to noble metal deposition, spinel crystals will begin to form in the SRL 165 composite waste glass pool in 24 hours. The total lid heater power required to initiate joule heating was the same as that during slurry-feeding. Results of a radiative heat transfer analysis in the plenum indicate that under the identical operating conditions, the startup capabilities of the SGM and the DWPF Melter are quite similar, despite a greater lid heater to melt surface area ratio in the DWPF Melter

Liquid-fed ceramic melter: a general description report

International Nuclear Information System (INIS)

Buelt, J.L.; Chapman, C.C.

1978-10-01

The Pacific Northwest Laboratory is conducting several research and development programs for the solidification of high-level wastes. The liquid-fed ceramic melter (LFCM) is a major component in the solidification process. This melter can solidify liquid high-level waste, as well as melt calcined waste with glass additives and then solidify the mixture. This report describes the LFCM system and shows the main features of the refractories, electrodes and power systems, melter box and lid, draining system, feeding system, and off-gas system

Energy Efficient Glass Melting - The Next Generation Melter

Energy Technology Data Exchange (ETDEWEB)

David Rue

2008-03-01

The objective of this project is to demonstrate a high intensity glass melter, based on the submerged combustion melting technology. This melter will serve as the melting and homogenization section of a segmented, lower-capital cost, energy-efficient Next Generation Glass Melting System (NGMS). After this project, the melter will be ready to move toward commercial trials for some glasses needing little refining (fiberglass, etc.). For other glasses, a second project Phase or glass industry research is anticipated to develop the fining stage of the NGMS process.

Test Plan: Phase 1, Hanford LLW melter tests, GTS Duratek, Inc

International Nuclear Information System (INIS)

Eaton, W.C.

1995-01-01

This document provides a test plan for the conduct of vitrification testing by a vendor in support of the Hanford Tank Waste Remediation System (TWRS) Low-Level Waste (LLW) Vitrification Program. The vendor providing this test plan and conducting the work detailed within it [one of seven selected for glass melter testing under Purchase Order MMI-SVV-384215] is GTS Duratek, Inc., Columbia, Maryland. The GTS Duratek project manager for this work is J. Ruller. This test plan is for Phase I activities described in the above Purchase Order. Test conduct includes melting of glass with Hanford LLW Double-Shell Slurry Feed waste simulant in a DuraMelter trademark vitrification system

Characterization of high level nuclear waste glass samples following extended melter idling

Energy Technology Data Exchange (ETDEWEB)

Fox, Kevin M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Peeler, David K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Kruger, Albert A. [USDOE Office of River Protection, Richland, WA (United States)

2015-06-16

The Savannah River Site Defense Waste Processing Facility (DWPF) melter was recently idled with glass remaining in the melt pool and riser for approximately three months. This situation presented a unique opportunity to collect and analyze glass samples since outages of this duration are uncommon. The objective of this study was to obtain insight into the potential for crystal formation in the glass resulting from an extended idling period. The results will be used to support development of a crystal-tolerant approach for operation of the high-level waste melter at the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Two glass pour stream samples were collected from DWPF when the melter was restarted after idling for three months. The samples did not contain crystallization that was detectible by X-ray diffraction. Electron microscopy identified occasional spinel and noble metal crystals of no practical significance. Occasional platinum particles were observed by microscopy as an artifact of the sample collection method. Reduction/oxidation measurements showed that the pour stream glasses were fully oxidized, which was expected after the extended idling period. Chemical analysis of the pour stream glasses revealed slight differences in the concentrations of some oxides relative to analyses of the melter feed composition prior to the idling period. While these differences may be within the analytical error of the laboratories, the trends indicate that there may have been some amount of volatility associated with some of the glass components, and that there may have been interaction of the glass with the refractory components of the melter. These changes in composition, although small, can be attributed to the idling of the melter for an extended period. The changes in glass composition resulted in a 70-100 °C increase in the predicted spinel liquidus temperature (TL) for the pour stream glass samples relative to the analysis of the melter feed prior to

Numerical analysis of historical change of the electric resistance in the TVF glass melter

International Nuclear Information System (INIS)

Kawamura, Takumi; Sakai, Takaaki

2004-09-01

Concerning to the TVF glass melter in the Tokai reprocessing center, it is being planned to detect the deposition of the noble metals in a glass melter and remove them periodically to extend the melter lifetime. Numerical analysis has been performed for the electric resistance evaluation in order to estimate the sedimentation situation and current density distribution from the melter resistance. Electric field analysis was carried out by using MAGNA-FIM code and the influence factors to melter resistance was evaluated concerning to the sedimentation situation and glass temperature. In addition, transitions of the sedimentation and melter resistances were estimated from the operation history of the TVF-1 melter. As a result, the followings were obtained. From the evaluation of the influence factors to melter resistance, it turns out that the volume and the noble metals concentration of a sediment influence notably to melter resistance when the sediment contacts to electrodes. The sediment temperature at the melter bottom has small sensitivity in case of the non-contact situation. The glass temperature in the melter upper part, however, has big sensitivity in melter resistance irrespective of the existence of contact. Based on the above sensitivity evaluation, Numerical analysis was carried out supposing the sedimentation process which suits to a melter resistance fall during the operation history of the TVF-1 melter. As input conditions, the voltage between electrodes and the temperature in the melter were referred from the operation history data. It was assumed that the noble metals concentration in a sediment increased constantly for every operation batch. As a result, the characteristics of melter resistance history was reproduced successfully in general. Thereby, it became prospective to predict the sedimentation situation by using the new resistance analysis model for the glass melter. (author)

DWPF Glass Melter Technology Manual: Volume 4

Energy Technology Data Exchange (ETDEWEB)

Iverson, D.C.

1993-12-31

This document details information about the design of a glass melter to be used at the Defense Waste Processing Facility located at the Savannah River Plant. Information contained in this document consists solely of a machine drawing and parts list and purchase orders with specifications of equipment used in the development of the melter.

DWPF Glass Melter Technology Manual: Volume 4

International Nuclear Information System (INIS)

Iverson, D.C.

1993-01-01

This document details information about the design of a glass melter to be used at the Defense Waste Processing Facility located at the Savannah River Plant. Information contained in this document consists solely of a machine drawing and parts list and purchase orders with specifications of equipment used in the development of the melter

Advanced Mixed Waste Treatment Project melter system preliminary design technical review meeting

Energy Technology Data Exchange (ETDEWEB)

Eddy, T.L.; Raivo, B.D.; Soelberg, N.R.; Wiersholm, O.

1995-02-01

The Idaho National Engineering Laboratory Advanced Mixed Waste Treatment Project sponsored a plasma are melter technical design review meeting to evaluate high-temperature melter system configurations for processing heterogeneous alpha-contaminated low-level radioactive waste (ALLW). Thermal processing experts representing Department of Energy contractors, the Environmental Protection Agency, and private sector companies participated in the review. The participants discussed issues and evaluated alternative configurations for three areas of the melter system design: plasma torch melters and graphite arc melters, offgas treatment options, and overall system configuration considerations. The Technical Advisory Committee for the review concluded that graphite arc melters are preferred over plasma torch melters for processing ALLW. Initiating involvement of stakeholders was considered essential at this stage of the design. For the offgas treatment system, the advisory committee raised the question whether to a use wet-dry or a dry-wet system. The committee recommended that the waste stream characterization, feed preparation, and the control system are essential design tasks for the high-temperature melter treatment system. The participants strongly recommended that a complete melter treatment system be assembled to conduct tests with nonradioactive surrogate waste material. A nonradioactive test bed would allow for inexpensive design and operational changes prior to assembling a system for radioactive waste treatment operations.

Advanced Mixed Waste Treatment Project melter system preliminary design technical review meeting

International Nuclear Information System (INIS)

Eddy, T.L.; Raivo, B.D.; Soelberg, N.R.; Wiersholm, O.

1995-02-01

The Idaho National Engineering Laboratory Advanced Mixed Waste Treatment Project sponsored a plasma are melter technical design review meeting to evaluate high-temperature melter system configurations for processing heterogeneous alpha-contaminated low-level radioactive waste (ALLW). Thermal processing experts representing Department of Energy contractors, the Environmental Protection Agency, and private sector companies participated in the review. The participants discussed issues and evaluated alternative configurations for three areas of the melter system design: plasma torch melters and graphite arc melters, offgas treatment options, and overall system configuration considerations. The Technical Advisory Committee for the review concluded that graphite arc melters are preferred over plasma torch melters for processing ALLW. Initiating involvement of stakeholders was considered essential at this stage of the design. For the offgas treatment system, the advisory committee raised the question whether to a use wet-dry or a dry-wet system. The committee recommended that the waste stream characterization, feed preparation, and the control system are essential design tasks for the high-temperature melter treatment system. The participants strongly recommended that a complete melter treatment system be assembled to conduct tests with nonradioactive surrogate waste material. A nonradioactive test bed would allow for inexpensive design and operational changes prior to assembling a system for radioactive waste treatment operations

Efficient particulate scrubber for glass melter off-gas

International Nuclear Information System (INIS)

Wright, G.T.

1983-01-01

Operation of joule-heated, continuous slurry-fed melters has demonstrated that off-gas aerosols are generated by entrainment of feed slurry and vaporization of volatile species from the melt. Effective off-gas stream decontamination for these aerosols can be obtained by utilizing a suitably designed and operated wet scrubber system. Results are presented for performance tests conducted with an air aspirating-type venturi scrubber processing a simulated melter off-gas aerosol. Mass overall removal efficiencies ranged from 99.5 to 99.8%. Details of the testing program and applications for melter off-gas system design are discussed

Graphite electrode arc melter demonstration Phase 2 test results

International Nuclear Information System (INIS)

Soelberg, N.R.; Chambers, A.G.; Anderson, G.L.; O'Connor, W.K.; Oden, L.L.; Turner, P.C.

1996-06-01

Several U.S. Department of Energy organizations and the U.S. Bureau of Mines have been collaboratively conducting mixed waste treatment process demonstration testing on the near full-scale graphite electrode submerged arc melter system at the Bureau's Albany (Oregon) Research Center. An initial test series successfully demonstrated arc melter capability for treating surrogate incinerator ash of buried mixed wastes with soil. The conceptual treatment process for that test series assumed that buried waste would be retrieved and incinerated, and that the incinerator ash would be vitrified in an arc melter. This report presents results from a recently completed second series of tests, undertaken to determine the ability of the arc melter system to stably process a wide range of open-quotes as-receivedclose quotes heterogeneous solid mixed wastes containing high levels of organics, representative of the wastes buried and stored at the Idaho National Engineering Laboratory (INEL). The Phase 2 demonstration test results indicate that an arc melter system is capable of directly processing these wastes and could enable elimination of an up-front incineration step in the conceptual treatment process

Compilation of information on modeling of inductively heated cold crucible melters

International Nuclear Information System (INIS)

Lessor, D.L.

1996-03-01

The objective of this communication, Phase B of a two-part report, is to present information on modeling capabilities for inductively heated cold crucible melters, a concept applicable to waste immobilization. Inductively heated melters are those in which heat is generated using coils around, rather than electrodes within, the material to be heated. Cold crucible or skull melters are those in which the melted material is confined within unmelted material of the same composition. This phase of the report complements and supplements Phase A by Loren Eyler, specifically by giving additional information on modeling capabilities for the inductively heated melter concept. Eyler discussed electrically heated melter modeling capabilities, emphasizing heating by electrodes within the melt or on crucible walls. Eyler also discussed requirements and resources for the computational fluid dynamics, heat flow, radiation effects, and boundary conditions in melter modeling; the reader is referred to Eyler's discussion of these. This report is intended for use in the High Level Waste (HLW) melter program at Hanford. We sought any modeling capabilities useful to the HLW program, whether through contracted research, code license for operation by Department of Energy laboratories, or existing codes and modeling expertise within DOE

Stress analysis of longwall top coal caving

Energy Technology Data Exchange (ETDEWEB)

Alehossein, H.; Poulsen, B.A. [CSIRO Exploration & Mining, Brisbane, Qld. (Australia)

2010-01-15

Longwall top coal caving (LTCC) is a relatively new method of mining thick coal seams that is currently achieving high productivity and efficiency. The technique is similar to traditional longwall mining in that a cutting head slices coal from the lower section of the coal seam onto a conveyor belt installed in front of the hydraulic support near the cutting face. In modern LTCC an additional rear conveyor belt is located behind the support, to which the flow of the caved coal from the upper part of the seam can be controlled by a moveable flipper attached to the canopy of the support. The mining method relies on the fracturing of the top coal by the front abutment pressure to achieve satisfactory caving into the rear conveyor. This paper develops a yield and caveability criterion based on in situ conditions in the top coal in advance of the mining face (yield) and behind the supports (caveability). Yielding and caving effects are combined into one single number called caving number (CN), which is the multiplication result of caving factor (CF) and yield factor (YF). Analytical derivations are based on in situ stress conditions, Mohr-Coulomb and/or Hoek-Brown rock failure criteria and an on-associated elastoplastic strain softening material behaviour. The yield and caveability criteria are in agreement with results from both numerical studies and mine data. The caving number is normalised to mining conditions of a reference Chinese mine (LMX mine) and is used to assess LTCC performance at fourteen other Chinese working longwalls that have had varying success with the LTCC technology. As a predictive model, results of this analytical/numerical study are useful to assess the potential success of caving in new LTCC operations and in different mining conditions.

High-Temperature Corrosion Study for the RPP Low Activity Waste Melter

International Nuclear Information System (INIS)

Marshall, K.M.

2003-01-01

The River Protection Program (RPP) low activity waste (LAW) melter design incorporates a series of bubblers used to increase convection in the molten glass. Through runs of a pilot melter at Duratek, Inc. in Columbia, Maryland, the bubblers have been identified as the major component limiting LAW melter availability, requiring frequent replacement due to corrosive degradation, primarily at the melt line. Laboratory experiments were performed to evaluate the performance of several alloys and coatings in simulated RPP low activity waste melter vapor space and molten glass environments. The performance of the alloys and coatings was studied in order to advance our understanding of how these materials react at the melt/air interface inside the melter. The ultimate goal was to identify a material with superior performance compared to that of Inconel 693, and to deliver a bubbler sub-assembly made of that material to the RPP LAW melter pilot facility for further testing

Steady state simulation of Joule heated ceramic melter for vitrification of high level liquid waste

Energy Technology Data Exchange (ETDEWEB)

Sugilal, G; Wattal, P K; Theyyunni, T K [Process Engineering and Systems Development Division, Bhabha Atomic Research Centre, Mumbai (India); Iyer, K N [Department of Mechanical Engineering, Indian Inst. of Tech., Mumbai (India)

1994-06-01

The Joule heated ceramic melter is emerging as an attractive alternative to metallic melters for high level waste vitrification. The inherent limitations with metallic melters viz., low capacity and short melter life, are overcome in a ceramic melter which can be adopted for continuous mode of operation. The ceramic melter has the added advantage of better operational flexibility. This paper describes the three dimensional model used for simulating the complex design conditions of the ceramic melter. (author).

Steady state simulation of Joule heated ceramic melter for vitrification of high level liquid waste

International Nuclear Information System (INIS)

Sugilal, G.; Wattal, P.K.; Theyyunni, T.K.; Iyer, K.N.

1994-01-01

The Joule heated ceramic melter is emerging as an attractive alternative to metallic melters for high level waste vitrification. The inherent limitations with metallic melters viz., low capacity and short melter life, are overcome in a ceramic melter which can be adopted for continuous mode of operation. The ceramic melter has the added advantage of better operational flexibility. This paper describes the three dimensional model used for simulating the complex design conditions of the ceramic melter. (author)

Settling of Spinel in A High-Level Waste Glass Melter

International Nuclear Information System (INIS)

Pavel Hrma; Pert Schill; Lubomir Nemec

2002-01-01

High-level nuclear waste is being vitrified, i.e., converted to a durable glass that can be stored in a safe repository for hundreds of thousands of years. Waste vitrification is accomplished in reactors call melters to which the waste is charged together with glass-forming additives. The mixture is electrically heated to a temperature as high as 1150 degree C (or even higher in advanced melters) to create a melt that becomes glass on cooling. This process is slow and expensive. Moreover, the melters that are currently in use or are going to be used in the U.S. are sensitive to clogging and thus cannot process melt in which solid particles are suspended. These particles settle and gradually accumulate on the melter bottom. Such particles, most often small crystals of spinel ( a mineral containing iron, nickel, chromium, and other minor oxides), inevitably occurred in the melt when the content of the waste in the glass (called waste loading) increases above a certain limit. To avoid the presence of solid particles in the melter, the waste loading is kept rather low, in average 15% lower than in glass formulated for more robust melters

Maximum organic carbon limits at different melter feed rates (U)

International Nuclear Information System (INIS)

Choi, A.S.

1995-01-01

This report documents the results of a study to assess the impact of varying melter feed rates on the maximum total organic carbon (TOC) limits allowable in the DWPF melter feed. Topics discussed include: carbon content; feed rate; feed composition; melter vapor space temperature; combustion and dilution air; off-gas surges; earlier work on maximum TOC; overview of models; and the results of the work completed

Determination of halogen content in glass for assessment of melter decontamination factors

International Nuclear Information System (INIS)

Goles, R.W.

1996-03-01

Melter decontamination factor (DF) values for the halogens (fluorine, chlorine, and iodine) are important to the Hanford Waste Vitrification Plant (HWVP) process because of the potential influence of DF on secondary-waste recycle strategies (fluorine and chlorine) as well as its impact on off-gas emissions (iodine). This study directly establishes the concentrations of halides-in HWVP simulated reference glasses rather than relying on indirect off-gas data. For fluorine and chlorine, pyrohydrolysis coupled with halide (ion chromatographic) detection has proven to be a useful analytical approach suitable for glass matrices, sensitive enough for the range of halogens encountered, and compatible with remote process support applications. Results obtained from pyrohydrolytic analysis of pilot-scale ceramic melter (PSCM) -22 and -23 glasses indicate that the processing behavior of fluorine and chlorine is quite variable even under similar processing conditions. Specifically, PSCM-23 glass exhibited a ∼90% halogen (F and Cl) retention efficiency, while only 20% was incorporated in PSCM-22 glass. These two sets of very dissimilar test results clearly do not form a sufficient basis for establishing design DF values for fluorine and chlorine. Because the present data do not provide any new halogen volatility information, but instead reconfirm the validity of previously obtained offgas derived values, melter DF values of 4, 2, and 1 for fluorine, chlorine, and iodine, respectively, are recommended for adoption; these values were conservatively established by a team of responsible engineers at Westinghouse Hanford Company (WHC) and Pacific Northwest Laboratory (PNL) on the basis of average behavior for many comparable melter tests. In the absence of further HWVP process data, these average melter DFs are the best values currently available

Vitrification of HLW in cold crucible melter

International Nuclear Information System (INIS)

Bordier, G.

2005-01-01

The performance of the vitrification process currently used in the La Hague commercial reprocessing plants has been continuously improved during more than ten years of operation. In parallel the CEA (French Atomic Energy Commission), COGEMA (Industrial Operator), and SGN (COGEMA's Engineering) have developed the cold crucible melter vitrification technology to obtain greater operating flexibility, increased plant availability and further reduction of secondary waste generated during operations. The cold crucible is a compact water-cooled melter in which the radioactive waste and the glass additives are melted by direct high frequency induction. The cooling of the melter produces a solidified glass layer that protects the melter's inner wall from corrosion. Because the heat is transferred directly to the melt, high operating temperatures can be achieved with no impact on the melter itself. COGEMA plans to implement the cold crucible technology to vitrify high level liquid waste from reprocessed spent U-Mo-Sn-Al fuel (used in gas cooled reactor). The cold crucible was selected for the vitrification of this particularly hard-to-process waste stream because it could not be reasonably processed in the standard hot induction melters currently used at the La Hague vitrification facilities: the waste has a high molybdenum content which makes it very corrosive and also requires a special high temperature glass formulation to obtain sufficiently high waste loading factors (12 % in molybdenum). A special glass formulation has been developed by the CEA and has been qualified through lab and pilot testing to meet standard waste acceptance criteria for final disposal of the U-Mo waste. The process and the associated technologies have been also qualified on a full-scale prototype at the CEA pilot facility in Marcoule. Engineering study has been integrated in parallel in order to take into account that the Cold Crucible should be installed remotely in one of the R7 vitrification

DWPF Melter Off-Gas Flammability Assessment for Sludge Batch 9

Energy Technology Data Exchange (ETDEWEB)

Choi, A. S. [Savannah River Site (SRS), Aiken, SC (United States)

2016-07-11

The slurry feed to the Defense Waste Processing Facility (DWPF) melter contains several organic carbon species that decompose in the cold cap and produce flammable gases that could accumulate in the off-gas system and create potential flammability hazard. To mitigate such a hazard, DWPF has implemented a strategy to impose the Technical Safety Requirement (TSR) limits on all key operating variables affecting off-gas flammability and operate the melter within those limits using both hardwired/software interlocks and administrative controls. The operating variables that are currently being controlled include; (1) total organic carbon (TOC), (2) air purges for combustion and dilution, (3) melter vapor space temperature, and (4) feed rate. The safety basis limits for these operating variables are determined using two computer models, 4-stage cold cap and Melter Off-Gas (MOG) dynamics models, under the baseline upset scenario - a surge in off-gas flow due to the inherent cold cap instabilities in the slurry-fed melter.

Literature review of arc/plasma, combustion, and joule-heated melter vitrification systems

International Nuclear Information System (INIS)

Freeman, C.J.; Abrigo, G.P.; Shafer, P.J.; Merrill, R.A.

1995-07-01

This report provides reviews of papers and reports for three basic categories of melters: arc/plasma-heated melters, combustion-heated melters, and joule-heated melters. The literature reviewed here represents those publications which may lend insight to phase I testing of low-level waste vitrification being performed at the Hanford Site in FY 1995. For each melter category, information from those papers and reports containing enough information to determine steady-state mass balance data is tabulated at the end of each section. The tables show the composition of the feed processed, the off-gas measured via decontamination factors, gross energy consumptions, and processing rates, among other data

Graphite electrode arc melter demonstration Phase 2 test results

Energy Technology Data Exchange (ETDEWEB)

Soelberg, N.R.; Chambers, A.G.; Anderson, G.L.; O`Connor, W.K.; Oden, L.L.; Turner, P.C.

1996-06-01

Several U.S. Department of Energy organizations and the U.S. Bureau of Mines have been collaboratively conducting mixed waste treatment process demonstration testing on the near full-scale graphite electrode submerged arc melter system at the Bureau`s Albany (Oregon) Research Center. An initial test series successfully demonstrated arc melter capability for treating surrogate incinerator ash of buried mixed wastes with soil. The conceptual treatment process for that test series assumed that buried waste would be retrieved and incinerated, and that the incinerator ash would be vitrified in an arc melter. This report presents results from a recently completed second series of tests, undertaken to determine the ability of the arc melter system to stably process a wide range of {open_quotes}as-received{close_quotes} heterogeneous solid mixed wastes containing high levels of organics, representative of the wastes buried and stored at the Idaho National Engineering Laboratory (INEL). The Phase 2 demonstration test results indicate that an arc melter system is capable of directly processing these wastes and could enable elimination of an up-front incineration step in the conceptual treatment process.

Modified IRC bench-scale arc melter for waste processing

International Nuclear Information System (INIS)

Eddy, T.L.; Sears, J.W.; Grandy, J.D.; Kong, P.C.; Watkins, A.D.

1994-03-01

This report describes the INEL Research Center (IRC) arc melter facility and its recent modifications. The arc melter can now be used to study volatilization of toxic and high vapor pressure metals and the effects of reducing and oxidizing (redox) states in the melt. The modifications include adding an auger feeder, a gas flow control and monitoring system, an offgas sampling and exhaust system, and a baghouse filter system, as well as improving the electrode drive, slag sampling system, temperature measurement and video monitoring and recording methods, and oxidation lance. In addition to the volatilization and redox studies, the arc melter facility has been used to produce a variety of glass/ceramic waste forms for property evaluation. Waste forms can be produced on a daily basis. Some of the melts performed are described to illustrate the melter's operating characteristics

Review of continuous ceramic-lined melter and associated experience at PNL

International Nuclear Information System (INIS)

Buelt, J.L.; Chapman, C.C.; Barnes, S.M.; Dierks, R.D.

1979-01-01

Development of continuous, ceramic-lined melters applicable to immobilization of radioactive wastes began at PNL in 1973. A comprehensive program is curretly in progress. The melters constructed at PNL have incorporated remote and reliable design features necessary for radioactive use. The extensive experience with vitrification of simulated wastes has proven the continuous melter's applicability to radioactive waste immobilization

Initial Laboratory-Scale Melter Test Results for Combined Fission Product Waste

Energy Technology Data Exchange (ETDEWEB)

Riley, Brian J.; Crum, Jarrod V.; Buchmiller, William C.; Rieck, Bennett T.; Schweiger, Michael J.; Vienna, John D.

2009-10-01

This report describes the methods and results used to vitrify a baseline glass, CSLNTM-C-2.5 in support of the AFCI (Advanced Fuel Cycle Initiative) using a Quartz Crucible Scale Melter at the Pacific Northwest National Laboratory. Document number AFCI-WAST-PMO-MI-DV-2009-000184.

Thermal stress analysis of an Am/Cm stabilization bushing melter

International Nuclear Information System (INIS)

Gong, C.; Hardy, B.J.

1996-01-01

Decades of nuclear material production at the Savannah River Site (SRS) has resulted in the generation of large quantities of the isotopes Am 243 and Cm 244 . Currently, the Am and Cm isotopes are stored as a nitric acid solution in a tank. The Am and Cm isotopes have great commercial value but must be transferred to the Oak Ridge National Laboratory (ORNL) for processing. The nitric acid solution contains other isotopes and is intensely radioactive, which makes storage a problem and precludes shipment in the liquid form. In order to stabilize the material for onsite storage and to permit transport the material from SRS to ORNL, it has been proposed that the Am and Cm be separated from other isotopes in the solution and vitrified. The vitrification process in the Platinum-Rhodium alloy vessel generates a wide spectrum of temperature distributions. The melter is partially supported by a suspension system and confined by the flexible insulation. The combination of the fluctuation of temperature distribution and variable boundary conditions, induces stresses and strains in the melter. The thermal stress analysis is carried out with the finite element code ABAQUS. This analysis is closely associated with the design, manufacture and testing of the melter. The results were compared with the test data

Americium/Curium Melter 2A Pilot Tests

International Nuclear Information System (INIS)

Smith, M.E.; Fellinger, A.P.; Jones, T.M.; Miller, C.B.; Miller, D.H.; Snyder, T.K.; Stone, M.E.; Witt, D.C.

1998-05-01

Isotopes of americium (Am) and curium (Cm) were produced in the past at the Savannah River Site (SRS) for research, medical, and radiological applications. These highly radioactive and valuable isotopes have been stored in an SRS reprocessing facility for a number of years. Vitrification of this solution will allow the material to be more safely stored until it is transported to the DOE Oak Ridge Reservation for use in research and medical applications. To this end, the Am/Cm Melter 2A pilot system, a full-scale non- radioactive pilot plant of the system to be installed at the reprocessing facility, was designed, constructed and tested. The full- scale pilot system has a frit and aqueous feed delivery system, a dual zone bushing melter, and an off-gas treatment system. The main items which were tested included the dual zone bushing melter, the drain tube with dual heating and cooling zones, glass compositions, and the off-gas system which used for the first time a film cooler/lower melter plenum. Most of the process and equipment were proven to function properly, but several problems were found which will need further work. A system description and a discussion of test results will be given

Final flush of the shielded cells melter

International Nuclear Information System (INIS)

Marshall, K.M.; Fellinger, T.L.; Harbour, J.R.

1997-01-01

A flush of the Savannah River Technology Center (SRTC) Shielded Cells melter was performed after the completion of a campaign to vitrify loaded crystalline silicotitanate (CST) ion exchange medium. The purpose of the flush was to lower levels of radioisotopes accumulated during the campaign and to lower the level of titanium dioxide present in the glass. This in turn would ready the melter for future campaigns involving the Defense Waste Processing Facility (DWPF)

GTS Duratek, phase I Hanford low-level waste melter tests: Final report

International Nuclear Information System (INIS)

Eaton, W.C.

1995-01-01

A multiphase program was initiated in 1994 to test commercially available melter technologies for the vitrification of the low-level waste (LLW) stream from defense waste stored in underground tanks at the Hanford Site in southeastern Washington State. Phase 1 of the melter demonstration tests using simulated LLW was completed during fiscal year 1995. This document is the final report on testing performed by GTS Duratek Inc. in Columbia, Maryland. GTS Duratek (one of the seven vendors selected) was chosen to demonstrate Joule heated melter technology under WHC subcontract number MMI-SVV-384215. The report contains description of the tests, observations, test data and some analysis of the data as it pertains to application of this technology for LLW vitrification. The document also contains summaries of the melter offgas reports issued as separate documents for the 100 kg melter (WHC-SD-WM-VI-028) and for the 1000 kg melter (WHC-SD-WM-VI-029)

Comparison of the rotary calciner-metallic melter and the slurry-fed ceramic melter technologies for vitrifying West Valley high-level wastes

International Nuclear Information System (INIS)

Chapman, C.C.

1983-01-01

Two processes which are believed applicable and available for vitrification of West Valley's high-level (HLW) wastes were technically evaluated and compared. The rotary calciner-metallic melter (AVH) and the slurry-fed ceramic melter (SFCM) were evaluated under the following general categories: process flow sheet, remote operability, safety and environmental considerations, and estimated cost and schedules

Development of HWVP melter/turntable components for canyon-remote maintenance and replacement

International Nuclear Information System (INIS)

Siemens, D.H.; Beary, M.M.; Berger, D.N.; Heath, W.O.; Larson, D.E.

1985-03-01

Remote operability and maintainability of vitrification equipment were assessed under shielded-cell conditions. The equipment tested will be applied to immobilize high-level and transuranic liquid waste slurries that resulted from plutonium production for defense weapons. Equipment tested included: (1) a turntable for handling waste canisters under the melter; (2) a removable discharge cone in the melter overflow section; (3) a thermocouple jumper that extends into a shielded cell; (4) remote instrument and electrical connectors; (5) remote, mechanical, and heat transfer aspects of the melter glass overflow section; (6) a reamer to clean out plugged nozzles in the melter top; (7) a closed circuit camera to view the melter interior; and (8) a device to retrieve samples of the glass product. 14 figs

A cave response to environmental changes in the Late Pleistocene: a study of Budimirica Cave sediments, Macedonia

Czech Academy of Sciences Publication Activity Database

Temovski, M.; Pruner, Petr; Hercman, H.; Bosák, Pavel

2016-01-01

Roč. 69, č. 3 (2016), s. 307-316 ISSN 1330-030X Institutional support: RVO:67985831 Keywords : cave sediments * palaeoenvironmental changes * Late Pleistocene * Budimirica Cave * Macedonia Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.595, year: 2016 http://www. geologia -croatica.hr/ojs/index.php/GC

Melter system technology testing for Hanford Site low-level tank waste vitrification

International Nuclear Information System (INIS)

Wilson, C.N.

1996-01-01

Following revisions to the Tri-Party Agreement for Hanford Site cleanup, which specified vitrification for Complete melter feasibility and system operability immobilization of the low-level waste (LLW) tests, select reference melter(s), and establish reference derived from retrieval and pretreatment of the radioactive LLW glass formulation that meets complete systems defense wastes stored in 177 underground tanks, commercial requirements (June 1996). Available melter technologies were tested during 1994 to 1995 as part of a multiphase program to select reference Submit conceptual design and initiate definitive design technologies for the new LLW vitrification mission

HWVP NCAW melter feed rheology FY 1993 testing and analyses: Letter report

International Nuclear Information System (INIS)

Smith, P.A.

1996-03-01

The Hanford Waste Vitrification Plant (HWVP) program has been established to immobilize selected Hanford nuclear wastes before shipment to a geologic repository. The HWVP program is directed by the U.S. Department of Energy (DOE). The Pacific Northwest Laboratory (PNL) provides waste processing and vitrification technology to assist the design effort. The focus of this letter report is melter feed rheology, Process/Product Development, which is part of the Task in the PNL HWVP Technology Development (PHTD) Project. Specifically, the melter feed must be transported to the liquid fed ceramic melter (LFCM) to ensure HWVP operability and the manufacture of an immobilized waste form. The objective of the PHTD Project slurry flow technology development is to understand and correlate dilute and concentrated waste, formatted waste, waste with recycle addition, and melter feed transport properties. The objectives of the work described in this document were to examine frit effects and several processing conditions on melter feed rheology. The investigated conditions included boiling time, pH, noble metal containing melter feed, solids loading, and aging time. The results of these experiments contribute to the understanding of melter feed rheology. This document is organized in eight sections. This section provides the introductory remarks, followed by Section 2.0 that contains conclusions and recommendations. Section 3.0 reviews the scientific principles, and Section 4.0 details the experimental methods. The results and discussion and the review of related rheology data are in Sections 5.0 and 6.0, respectively. Section 7.0, an analysis of NCAW melter feed rheology data, provides an overall review of melter feed with FY 91 frit. References are included in Section 8.0. This letter report satisfies contractor milestone PHTD C93-03.02E, as described in the FY 1993 Pacific Northwest Hanford Laboratory Waste Plant Technology Development (PHTD) Project Work Plan

Control of high-level radioactive waste-glass melters

International Nuclear Information System (INIS)

Bickford, D.F.; Coleman, C.J.

1990-01-01

The Defense Waste Processing Facility (DWPF) will immobilize Savannah River Site High Level Waste as a durable borosilicate glass for permanent disposal in a repository. The DWPF will be controlled based on glass composition. The following discussion is a preliminary analysis of the capability of the laboratory methods that can be used to control the glass composition, and the relationships between glass durability and glass properties important to glass melting. The glass durability and processing properties will be controlled by controlling the chemical composition of the glass. The glass composition will be controlled by control of the melter feed transferred from the Slurry Mix Evaporator (SME) to the Melter Feed Tank (MFT). During cold runs, tests will be conducted to demonstrate the chemical equivalence of glass sampled from the pour stream and glass removed from cooled canisters. In similar tests, the compositions of glass produced from slurries sampled from the SME and MFT will be compared to final product glass to determine the statistical relationships between melter feed and glass product. The total error is the combination of those associated with homogeneity in the SME or MFT, sampling, preparation of samples for analysis, instrument calibration, analysis, and the composition/property model. This study investigated the sensitivity of estimation of property data to the combination of variations from sampling through analysis. In this or a similar manner, the need for routine glass product sampling will be minimized, and glass product characteristics will be assured before the melter feed is committed to the melter

Technology of off-gas treatment for liquid-fed ceramic melters

Energy Technology Data Exchange (ETDEWEB)

Scott, P.A.; Goles, R.W.; Peters, R.D.

1985-05-01

The technology for treating off gas from liquid-fed ceramic melters (LFCMs) has been under development at the Pacific Northwest Laboratory since 1977. This report presents the off-gas technology as developed at PNL and by others to establish a benchmark of development and to identify technical issues. Tests conducted on simulated (nonradioactive) wastes have provided data that allow estimation of melter off-gas composition for a given waste. Mechanisms controlling volatilization of radionuclides and noxious gases are postulated, and correlations between melter operation and emissions are presented. This report is directed to those familiar with LFCM operation. Off-gas treatment systems always require primary quench scrubbers, aerosol scrubbers, and final particulate filters. Depending on the composition of the off gas, equipment for removal of ruthenium, iodine, tritium, and noxious gases may also be needed. Nitrogen oxides are the most common noxious gases requiring treatment, and can be controlled by aqueous absorption or catalytic conversion with ammonia. High efficiency particulate air (HEPA) filters should be used for final filtration. The design criteria needed for an off-gas system can be derived from emission regulations and composition of the melter feed. Conservative values for melter off-gas composition can be specified by statistical treatment of reported off-gas data. Statistical evaluation can also be used to predict the frequency and magnitude of normal surge events that occur in the melter. 44 refs., 28 figs., 17 tabs.

Advanced waste form and melter development for treatment of troublesome high-level wastes

Energy Technology Data Exchange (ETDEWEB)

Marra, James [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Kim, Dong -Sang [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Maio, Vincent [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-09-02

A number of waste components in US defense high level radioactive wastes (HLW) have proven challenging for current Joule heated ceramic melter (JHCM) operations and have limited the ability to increase waste loadings beyond already realized levels. Many of these "troublesome" waste species cause crystallization in the glass melt that can negatively impact product quality or have a deleterious effect on melter processing. Recent efforts at US Department of Energy laboratories have focused on understanding crystallization behavior within HLW glass melts and investigating approached to mitigate the impacts of crystallization so that increases in waste loading can be realized. Advanced glass formulations have been developed to highlight the unique benefits of next-generation melter technologies such as the Cold Crucible Induction Melter (CCIM). Crystal-tolerant HLW glasses have been investigated to allow sparingly soluble components such as chromium to crystallize in the melter but pass out of the melter before accumulating.

Cold crucible induction melter studies for making glass ceramic waste forms: A feasibility assessment

International Nuclear Information System (INIS)

Crum, Jarrod; Maio, Vince; McCloy, John; Scott, Clark; Riley, Brian; Benefiel, Brad; Vienna, John; Archibald, Kip; Rodriguez, Carmen; Rutledge, Veronica; Zhu, Zihua; Ryan, Joe; Olszta, Matthew

2014-01-01

Glass ceramics are being developed to immobilize fission products, separated from used nuclear fuel by aqueous reprocessing, into a stable waste form suitable for disposal in a geological repository. This work documents the glass ceramic formulation at bench scale and for a scaled melter test performed in a pilot-scale (∼1/4 scale) cold crucible induction melter (CCIM). Melt viscosity, electrical conductivity, and crystallization behavior upon cooling were measured on a small set of compositions to select a formulation for melter testing. Property measurements also identified a temperature range for melter operation and cooling profiles necessary to crystallize the targeted phases in the waste form. Bench scale and melter run results successfully demonstrate the processability of the glass ceramic using the CCIM melter technology

Calculating flux to predict future cave radon concentrations

Czech Academy of Sciences Publication Activity Database

Rowberry, Matthew David; Martí, Xavier; Frontera, C.; Van De Wiel, M.J.; Briestenský, Miloš

2016-01-01

Roč. 157, JUN (2016), 16-26 ISSN 0265-931X R&D Projects: GA MŠk LM2010008 Institutional support: RVO:67985891 ; RVO:68378271 Keywords : cave radon concentration * cave radon flux * cave ventilation * radioactive decay * fault slip * numerical modelling Subject RIV: DC - Siesmology, Volcanology, Earth Structure; BG - Nuclear, Atomic and Molecular Physics, Colliders (FZU-D) Impact factor: 2.310, year: 2016

Redox control of electric melters with complex feed compositions. Part I: analytical methods and models

International Nuclear Information System (INIS)

Bickford, D.F.; Diemer, R.B. Jr.

1985-01-01

The redox state of glass from electric melters with complex feed compositions is determined by balance between gases above the melt, and transition metals and organic compounds in the feed. Part I discusses experimental and computational methods of relating flowrates and other melter operating conditions to the redox state of glass, and composition of the melter offgas. Computerized thermodynamic computational methods are useful in predicting the sequence and products of redox reactions and in assessing individual process variations. Melter redox state can be predicted by combining monitoring of melter operating conditions, redox measurement of fused melter feed samples, and periodic redox measurement of product. Mossbauer spectroscopy, and other methods which measure Fe(II)/Fe(III) in glass, can be used to measure melter redox state. Part II develops preliminary operating limits for the vitrification of High-Level Radioactive Waste. Limits on reducing potential to preclude the accumulation of combustible gases, accumulation of sulfides and selenides, and degradation of melter components are the most critical. Problems associated with excessively oxidizing conditions, such as glass foaming and potential ruthenium volatility, are controlled when sufficient formic acid is added to adjust melter feed rheology

Vitrification of Hanford wastes in a joule-heated ceramic melter and evaluation of resultant canisterized product

International Nuclear Information System (INIS)

Chapman, C.C.; Buelt, J.L.; Slate, S.C.; Katayama, Y.B.; Bunnell, L.R.

1979-08-01

Experience gained in the week-long vitrification test and characterization of the glass produced in the run support the following conclusions: The Hanford waste simulated in this test can be readily vitrified in a joule-heated ceramic melter. Physical properties of the molten glass were entirely compatible with melter operation. The average feed rate of 106 kg/h is high enough to make the ceramic melter a feasible piece of equipment for vitrifying Hanford wastes. The glass produced in this trial had good chemical durability, 6(10) -5 g/cm 2 -d. When one of the canisters was purposely dropped onto a steel pad, the damage was limited to deformation of the steel can in the impact area, cracking of a weld, and fracturing of glass in the immediate vicinity of the impact area. No glass was released from the canister as a result of the drop test. The results of this vitrification test support the technical feasibility of vitrifying Hanford wastes by means of a joule-heated ceramic melter. Surface area for large glass castings is equivalent to the mass median particle diameters between 4.27 cm (1.75 in.) and 8.91 cm (3.51 in.) even when allowed to cool rapidly by standing in ambient air. Large canisters (up to 0.91 m in dia) can be cast without large voids while standing in air if the fill rate is over 100 kg/h. 34 figures, 10 tables

Fish mitigate trophic depletion in marine cave ecosystems.

Science.gov (United States)

Bussotti, Simona; Di Franco, Antonio; Bianchi, Carlo Nike; Chevaldonné, Pierre; Egea, Lea; Fanelli, Emanuela; Lejeusne, Christophe; Musco, Luigi; Navarro-Barranco, Carlos; Pey, Alexis; Planes, Serge; Vieux-Ingrassia, Jean Vincent; Guidetti, Paolo

2018-06-15

Dark marine habitats are often characterized by a food-limited condition. Peculiar dark habitats include marine caves, characterized by the absence of light and limited water flow, which lead to reduced fluxes of organic matter for cave-dwelling organisms. We investigated whether the most abundant and common cave-dwelling fish Apogon imberbis has the potential to play the role of trophic vector in Mediterranean marine caves. We first analysed stomach contents to check whether repletion changes according to a nycthemeral cycle. We then identified the prey items, to see whether they belong to species associated with cave habitats or not. Finally, we assessed whether A. imberbis moves outside marine caves at night to feed, by collecting visual census data on A. imberbis density both inside and outside caves, by day and by night. The stomach repletion of individuals sampled early in the morning was significantly higher than later in the day. Most prey were typical of habitats other than caves. A. imberbis was on average more abundant within caves during the day and outside during the night. Our study supports the hypothesis regarding the crucial trophic role of A. imberbis in connecting Mediterranean marine caves with external habitats.

Materials and design experience in a slurry-fed electric glass melter

International Nuclear Information System (INIS)

Barnes, S.M.; Larson, D.E.

1981-08-01

The design of a slurry-fed electric gas melter and an examination of the performance and condition of the construction materials were completed. The joule-heated, ceramic-lined melter was constructed to test the applicability of materials and processes for high-level waste vitrification. The developmental Liquid-Fed Ceramic Melter (LFCM) was operated for three years with simulated high-level waste and was subjected to conditions more severe than those expected for a nuclear waste vitrification plant

Gaseous and particulate emissions from a DC arc melter.

Science.gov (United States)

Overcamp, Thomas J; Speer, Matthew P; Griner, Stewart J; Cash, Douglas M

2003-01-01

Tests treating soils contaminated with metal compounds and radionuclide surrogates were conducted in a DC arc melter. The soil melted, and glassy or ceramic waste forms with a separate metal phase were produced. Tests were run in the melter plenum with either air or N2 purge gases. In addition to nitrogen, the primary emissions of gases were CO2, CO, oxygen, methane, and oxides of nitrogen (NO(x)). Although the gas flow through the melter was low, the particulate concentrations ranged from 32 to 145 g/m3. Cerium, a nonradioactive surrogate for plutonium and uranium, was not enriched in the particulate matter (PM). The PM was enriched in cesium and highly enriched in lead.

Slurry feed variability in West Valley's melter feed tank and sampling system

International Nuclear Information System (INIS)

Fow, C.L.; Kurath, D.E.; Pulsipher, B.A.; Bauer, B.P.

1989-04-01

The present plan for disposal of high-level wastes at West Valley is to vitrify the wastes for disposal in deep geologic repository. The vitrification process involves mixing the high-level wastes with glass-forming chemicals and feeding the resulting slurry to a liquid-fed ceramic melter. Maintaining the quality of the glass product and proficient melter operation depends on the ability of the melter feed system to produce and maintain a homogeneous mixture of waste and glass-former materials. To investigate the mixing properties of the melter feed preparation system at West Valley, a statistically designed experiment was conducted using synthetic melter feed slurry over a range of concentrations. On the basis of the statistical data analysis, it was found that (1) a homogeneous slurry is produced in the melter feed tank, (2) the liquid-sampling system provides slurry samples that are statistically different from the slurry in the tank, and (3) analytical measurements are the major source of variability. A statistical quality control program for the analytical laboratory and a characterization test of the actual sampling system is recommended. 1 ref., 5 figs., 1 tab

Assessment of water/glass interactions in waste glass melter operation

International Nuclear Information System (INIS)

Postma, A.K.; Chapman, C.C.; Buelt, J.L.

1980-04-01

A study was made to assess the possibility of a vapor explosion in a liquid-fed glass melter and during off-standard conditions for other vitrification processes. The glass melter considered is one designed for the vitrification of high-level nuclear wastes and is comprised of a ceramic-lined cavity with electrodes for joule heating and processing equipment required to add feed and withdraw glass. Vapor explosions needed to be considered because experience in other industrial processes has shown that violent interactions can occur if a hot liquid is mixed with a cooler, vaporizable liquid. Available experimental evidence and theoretical analyses indicate that destructive glass/water interactions are low probability events, if they are possible at all. Under standard conditions, aspects of liquid-fed melter operation which work against explosive interactions include: (1) the aqueous feed is near its boiling point; (2) the feed contains high concentrations of suspended particles; (3) molten glass has high viscosity (greater than 20 poise); and (4) the glass solidifies before film boiling can collapse. While it was concluded that vapor explosions are not expected in a liquid-fed melter, available information does not allow them to be ruled out altogether. Several precautionary measures which are easily incorporated into melter operation procedures were identified and additional experiments were recommended

Development of equipments for remote dismantling of joule heated ceramic melter

International Nuclear Information System (INIS)

Badgujar, Kiran T.; Usarkar, Sachin G.; Kumar, Binu; Nair, K.N.S.

2011-01-01

Joule Heated Ceramic Melter (JHCM) technology has been adopted for industrial scale vitrification of high level liquid waste (HLLW) at Tarapur and Kalpakkam. The melter installed at Advanced Vitrification System (AVS), Tarapur has immobilized 175 m 3 of HLLW in 113 canisters containing 11533Kg of Vitrified Waste Product (VWP). The melter has been in operation for 3 years before shutdown. It is intended to demonstrate the complete procedure of dismantling of Joule Melter in 1:1 scale prior to going in for actual dismantling in the hot cell. The Melter consists of an assembly of Inconel/SS pipes and plates, fuse cast refractories, thermal insulations of various types inside a SS casing and possibly some glass which is left over in the melter. Dismantling of melter involves remote cutting of the outer casing, pipe connections, electrical connections and removal, sizing and packing of internals in a sequential manner to minimise generation of secondary waste. The challenge involves development of remotely operated multi-degrees of freedom fixtures, modification and performance testing of standard industrial cutting and breaking tools and adapting them for remote operations. The work also involves development of equipments for collection of waste generated during the dismantling operation and packaging thus in special packages. Remotely actuated fixtures have been developed for remote top plate and side electrodes cutting. Remotely operated grab has been developed for handling of loose material and grippers have been developed for handling of refractory blocks. Industrial vacuum suction device has been modified into split units to enable for reducing the spread of powder material, while dismantling in progress. The performance test of developed fixtures, equipments, cutting and breaking tools have been carried on 1:1 scale melter model. Various parameters like cutting speed, cutting tool performance, generation of waste volume has been measured and analysed for

Maximum total organic carbon limits at different DWPF melter feed maters (U)

International Nuclear Information System (INIS)

Choi, A.S.

1996-01-01

The document presents information on the maximum total organic carbon (TOC) limits that are allowable in the DWPF melter feed without forming a potentially flammable vapor in the off-gas system were determined at feed rates varying from 0.7 to 1.5 GPM. At the maximum TOC levels predicted, the peak concentration of combustible gases in the quenched off-gas will not exceed 60 percent of the lower flammable limit during a 3X off-gas surge, provided that the indicated melter vapor space temperature and the total air supply to the melter are maintained. All the necessary calculations for this study were made using the 4-stage cold cap model and the melter off-gas dynamics model. A high-degree of conservatism was included in the calculational bases and assumptions. As a result, the proposed correlations are believed to by conservative enough to be used for the melter off-gas flammability control purposes

Investigation of corrosion experienced in a spray calciner/ceramic melter vitrification system

International Nuclear Information System (INIS)

Dierks, R.D.; Mellinger, G.B.; Miller, F.A.; Nelson, T.A.; Bjorklund, W.J.

1980-08-01

After periodic testing of a large-scale spray calciner/ceramic melter vitrification system over a 2-yr period, sufficient corrosion was noted on various parts of the vitrification system to warrant its disassembly and inspection. A majority of the 316 SS sintered metal filters on the spray calciner were damaged by chemical corrosion and/or high temperature oxidation. Inconel-601 portions of the melter lid were attacked by chlorides and sulfates which volatilized from the molten glass. The refractory blocks, making up the walls of the melter, were attacked by the waste glass. This attack was occurring when operating temperatures were >1200 0 C. The melter floor was protected by a sludge layer and showed no corrosion. Corrosion to the Inconel-690 electrodes was minimal, and no corrosion was noted in the offgas treatment system downstream of the sintered metal filters. It is believed that most of the melter corrosion occurred during one specific operating period when the melter was operated at high temperatures in an attempt to overcome glass foaming behavior. These high temperatures resulted in a significant release of volatile elements from the molten glass, and also created a situation where the glass was very fluid and convective, which increased the corrosion rate of the refractories. Specific corrosion to the calciner components cannot be proven to have occurred during a specific time period, but the mechanisms of attack were all accelerated under the high-temperature conditions that were experienced with the melter. A review of the materials of construction has been made, and it is concluded that with controlled operating conditions and better protection of some materials of construction corrosion of these systems will not cause problems. Other melter systems operating under similar strenuous conditions have shown a service life of 3 yr

Impact Of Melter Internal Design On Off-Gas Flammability

International Nuclear Information System (INIS)

Choi, A. S.; Lee, S. Y.

2012-01-01

The purpose of this study was to: (1) identify the more dominant design parameters that can serve as the quantitative measure of how prototypic a given melter is, (2) run the existing DWPF models to simulate the data collected using both DWPF and non-DWPF melter configurations, (3) confirm the validity of the selected design parameters by determining if the agreement between the model predictions and data is reasonably good in light of the design and operating conditions employed in each data set, and (4) run Computational Fluid Dynamics (CFD) simulations to gain new insights into how fluid mixing is affected by the configuration of melter internals and to further apply the new insights to explaining, for example, why the agreement is not good

The future of the CAVE

KAUST Repository

DeFanti, Thomas; Acevedo-Feliz, Daniel; Ainsworth, Richard; Brown, Maxine; Cutchin, Steven; Dawe, Gregory; Doerr, Kai-Uwe; Johnson, Andrew; Knox, Christopher; Kooima, Robert; Kuester, Falko; Leigh, Jason; Long, Lance; Otto, Peter; Petrovic, Vid; Ponto, Kevin; Prudhomme, Andrew; Rao, Ramesh; Renambot, Luc; Sandin, Daniel; Schulze, Jurgen; Smarr, Larry; Srinivasan, Madhusudhanan; Weber, Philip; Wickham, Gregory

2011-01-01

The CAVE, a walk-in virtual reality environment typically consisting of 4–6 3 m-by-3 m sides of a room made of rear-projected screens, was first conceived and built in 1991. In the nearly two decades since its conception, the supporting technology has improved so that current CAVEs are much brighter, at much higher resolution, and have dramatically improved graphics performance. However, rear-projection-based CAVEs typically must be housed in a 10 m-by-10 m-by-10 m room (allowing space behind the screen walls for the projectors), which limits their deployment to large spaces. The CAVE of the future will be made of tessellated panel displays, eliminating the projection distance, but the implementation of such displays is challenging. Early multi-tile, panel-based, virtual-reality displays have been designed, prototyped, and built for the King Abdullah University of Science and Technology (KAUST) in Saudi Arabia by researchers at the University of California, San Diego, and the University of Illinois at Chicago. New means of image generation and control are considered key contributions to the future viability of the CAVE as a virtual-reality device.

U.S. Bureau of Mines, Phase 1 Hanford low-level waste melter tests. Final report

International Nuclear Information System (INIS)

Eaton, W.C.; Oden, L.L.; O'Connor, W.K.

1995-11-01

A multiphase program was initiated in 1994 to test commercially available melter technologies for the vitrification of the low-level waste (LLW) stream from defense wastes stored in underground tanks at the Hanford Site in southeastern Washington State. Phase 1 of the melter demonstration tests using simulated LLW was completed during fiscal year 1995. This document is the melter offgas report on testing performed by the U.S. Department of the Interior, Bureau of Mines, Albany Research Center in Albany, Oregon. The Bureau of Mines (one of the seven vendors selected) was chosen to demonstrate carbon electrode melter technology (also called carbon arc or electric arc) under WHC Subcontract number MMI-SVV-384216. The report contains description of the tests, observation, test data and some analysis of the data as it pertains to application of this technology for LLW vitrification. Testing consisted of melter feed preparation and three melter tests, the first of which was to fulfill the requirements of the statement of work (WHC-SD-EM-RD-044), and the second and third were to address issues identified during the first test. The document also contains summaries of the melter offgas report issued as a separate document U.S. Bureau of Mines, Phase 1 Hanford Low-Level Waste Melter Tests: Melter Offgas Report (WHC-SD-WM-VI-032)

U.S. Bureau of Mines, Phase 1 Hanford low-level waste melter tests. Final report

Energy Technology Data Exchange (ETDEWEB)

Eaton, W.C. [Westinghouse Hanford Co., Richland, WA (United States); Oden, L.L.; O`Connor, W.K. [Bureau of Mines, Albany, OR (United States). Albany Research Center

1995-11-01

A multiphase program was initiated in 1994 to test commercially available melter technologies for the vitrification of the low-level waste (LLW) stream from defense wastes stored in underground tanks at the Hanford Site in southeastern Washington State. Phase 1 of the melter demonstration tests using simulated LLW was completed during fiscal year 1995. This document is the melter offgas report on testing performed by the U.S. Department of the Interior, Bureau of Mines, Albany Research Center in Albany, Oregon. The Bureau of Mines (one of the seven vendors selected) was chosen to demonstrate carbon electrode melter technology (also called carbon arc or electric arc) under WHC Subcontract number MMI-SVV-384216. The report contains description of the tests, observation, test data and some analysis of the data as it pertains to application of this technology for LLW vitrification. Testing consisted of melter feed preparation and three melter tests, the first of which was to fulfill the requirements of the statement of work (WHC-SD-EM-RD-044), and the second and third were to address issues identified during the first test. The document also contains summaries of the melter offgas report issued as a separate document U.S. Bureau of Mines, Phase 1 Hanford Low-Level Waste Melter Tests: Melter Offgas Report (WHC-SD-WM-VI-032).

Control of DWPF melter feed composition

International Nuclear Information System (INIS)

Brown, K.G.; Edwards, R.E.; Postles, R.L.; Randall, C.T.

1989-01-01

The Defense Waste Processing Facility will be used to immobilize Savannah River Site high-level waste into a stable borosilicate glass for disposal in a geologic repository. Proper control of the melter feed composition in this facility is essential to the production of glass which meets product durability constraints dictated by repository regulations and facility processing constraints dictated by melter design. A technique has been developed which utilizes glass property models to determine acceptable processing regions based on the multiple constraints imposed on the glass product and to display these regions graphically. This system along with the batch simulation of the process is being used to form the basis for the statistical process control system for the facility

Helium Isotopes and Noble Gas Abundances of Cave Dripping Water in Three Caves in East Asia

Science.gov (United States)

Chen, A. T.; Shen, C. C.; Tan, M.; Li, T.; Uemura, R.; Asami, R.

2015-12-01

Paleo-temperature recorded in nature archives is a critical parameter to understand climate change in the past. With advantages of unique inert chemical characteristics and sensitive solubilities with temperature, dissolved noble gases in speleothem inclusion water were recently proposed to retrieve terrestrial temperature history. In order to accurately apply this newly-developed speleothem noble gas temperature (NGT) as a reliable proxy, a fundamental issue about behaviors of noble gases in the karst should be first clarified. In this study, we measured noble gas contents in air and dripping water to evaluate any ratio deviation between noble gases. Cave dripping water samples was collected from three selected caves, Shihua Cave in northern China, Furong Cave in southwestern, and Gyukusen Cave in an island located in the western Pacific. For these caves are characterized by a thorough mixing and long-term storage of waters in a karst aquifer by the absence of seasonal oxygen isotope shifts. Ratios of dripping water noble gases are statistically insignificant from air data. Helium isotopic ratios in the dripping water samples match air value. The results indicate that elemental and isotopic signatures of noble gases from air can be frankly preserved in the epikarst and support the fidelity of NGT techniques.

Letter report: Cold crucible melter assessment

International Nuclear Information System (INIS)

Elliott, M.L.

1996-03-01

One of the activities of the PNL Vitrification Technology Development (PVTD) Project is to assist the Tank Waste Remediation Systems (TWRS) Program in determining which melter systems should be performance tested for potential implementation in the high-level waste (HLW) vitrification plant. The Richland Operations Office (RL) has recommended that the Cold Crucible Melter (CCM) be evaluated as a candidate ''next generation'' melter. As a result, the CCM System Evaluation cost account was established under the PVTD Project so that the CCM could be initially assessed on a high-priority basis. This letter report summarizes a brief initial review and assessment of the CCM. Using the recommendations made in this document, Westinghouse Hanford Company (WHC) and RL will make a decision regarding the urgency of performance testing the CCM. If the decision is favorable, a subcontract will be negotiated for performance testing of a CCM using Hanford HLW simulants in a pilot-scale facility. Because of the aggressive nature of the schedule, the CCM evaluation was not rigorous. The evaluation consisted of a literature review and interviews with proponents of the technology during a recent trip to France. This letter report summarizes the evaluation and makes recommendations regarding further work in this area

Simulated oxygen isotopes in cave drip water and speleothem calcite in European caves

Directory of Open Access Journals (Sweden)

A. Wackerbarth

2012-11-01

Full Text Available Interpreting stable oxygen isotope (δ¹⁸O records from stalagmites is still one of the complex tasks in speleothem research. Here, we present a novel model-based approach, where we force a model describing the processes and modifications of δ¹⁸O from rain water to speleothem calcite (Oxygen isotope Drip water and Stalagmite Model – ODSM with the results of a state-of-the-art atmospheric general circulation model enhanced by explicit isotope diagnostics (ECHAM5-wiso. The approach is neither climate nor cave-specific and allows an integrated assessment of the influence of different varying climate variables, e.g. temperature and precipitation amount, on the isotopic composition of drip water and speleothem calcite.

First, we apply and evaluate this new approach under present-day climate conditions using observational data from seven caves from different geographical regions in Europe. Each of these caves provides measured δ¹⁸O values of drip water and speleothem calcite to which we compare our simulated isotope values. For six of the seven caves modeled δ¹⁸O values of drip water and speleothem calcite are in good agreement with observed values. The mismatch of the remaining caves might be caused by the complexity of the cave system, beyond the parameterizations included in our cave model.

We then examine the response of the cave system to mid-Holocene (6000 yr before present, 6 ka climate conditions by forcing the ODSM with ECHAM5-wiso results from 6 ka simulations. For a set of twelve European caves, we compare the modeled mid-Holocene-to-modern difference in speleothem calcite δ¹⁸O to available measurements. We show that the general European changes are simulated well. However, local discrepancies are found, and might be explained either by a too low model resolution, complex local soil-atmosphere interactions affecting evapotranspiration or by cave specific factors

Cold-Crucible Design Parameters for Next Generation HLW Melters

International Nuclear Information System (INIS)

Gombert, D.; Richardson, J.; Aloy, A.; Day, D.

2002-01-01

The cold-crucible induction melter (CCIM) design eliminates many materials and operating constraints inherent in joule-heated melter (JHM) technology, which is the standard for vitrification of high-activity wastes worldwide. The cold-crucible design is smaller, less expensive, and generates much less waste for ultimate disposal. It should also allow a much more flexible operating envelope, which will be crucial if the heterogeneous wastes at the DOE reprocessing sites are to be vitrified. A joule-heated melter operates by passing current between water-cooled electrodes through a molten pool in a refractory-lined chamber. This design is inherently limited by susceptibility of materials to corrosion and melting. In addition, redox conditions and free metal content have exacerbated materials problems or lead to electrical short-circuiting causing failures in DOE melters. In contrast, the CCIM design is based on inductive coupling of a water-cooled high-frequency electrical coil with the glass, causing eddycurrents that produce heat and mixing. A critical difference is that inductance coupling transfers energy through a nonconductive solid layer of slag coating the metal container inside the coil, whereas the jouleheated design relies on passing current through conductive molten glass in direct contact with the metal electrodes and ceramic refractories. The frozen slag in the CCIM design protects the containment and eliminates the need for refractory, while the corrosive molten glass can be the limiting factor in the JH melter design. The CCIM design also eliminates the need for electrodes that typically limit operating temperature to below 1200 degrees C. While significant marketing claims have been made by French and Russian technology suppliers and developers, little data is available for engineering and economic evaluation of the technology, and no facilities are available in the US to support testing. A currently funded project at the Idaho National Engineering

Clastic cave deposits in Botovskaya cave (Eastern Siberia, Russian Federation)

Czech Academy of Sciences Publication Activity Database

Kadlec, Jaroslav; Chadima, Martin; Lisá, Lenka; Hercman, H.; Osintsev, A.; Oberhänsli, H.

2008-01-01

Roč. 70, č. 3 (2008), s. 142-155 ISSN 1090-6924 Institutional research plan: CEZ:AV0Z30130516 Keywords : cave sediments * mineral magnetism * Botovskaya Cave Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 0.532, year: 2008 http://www.caves.org/pub/journal/Journal_of_Cave_and_Karst_Studies_volume_70.htm

Current status of the active test at RRP and development programs for the advanced melter

International Nuclear Information System (INIS)

Kanehira, Norio

2016-01-01

The vitrification facility in Rokkasho Reprocessing Plant started the active tests to solidify HAW into the glass in 2007 which was the examination of the final stage before the operation, but the active test had to be discontinued due to the trouble of glass melter operation with down of pouring by deposit of noble metals on the melter bottom. After the equipment and operating conditions were improved in response to the result of the mock-up tests, a series of active tests were restarted active tests in May, 2012. These tests were finished with enough confirmation of stability in the state such as glass temperature and controlling the noble metals. JNFL has been developed the advanced melter, Joule heated ceramic melter, and the design of the advanced melter is largely different from the existing one. For the confirmation of the advanced melter performances, the full-scale inactive tests had been performed and successfully finished. This paper describes outline of development for advanced melter in Rokkasho Reprocessing Plant. (author)

The behavior and effects of the noble metals in the DWPF melter system

International Nuclear Information System (INIS)

Hutson, N.D.; Smith, M.E.

1992-01-01

Fission-product noble metals have caused severe operating problems in numerous worldwide waste vitrification facilities. These dense, highly conductive noble metals have tended to accumulate on the floor of joule-heated glass melters causing electrical distortions which have, in some occurrences, rendered the melter inoperable. A pilot scale vitrification research facility at the U.S. Department of Energy's Savannah River Laboratory has been operated for more than a year with simulated feed streams containing noble metals. In this paper the behavior of these noble metals in the melter system and final glass product and their effects on the scaled DWPF-type melter are discussed

Feed process studies: Research-Scale Melter

Energy Technology Data Exchange (ETDEWEB)

Whittington, K.F.; Seiler, D.K.; Luey, J.; Vienna, J.D.; Sliger, W.A.

1996-09-01

In support of a two-phase approach to privatizing the processing of hazardous and radioactive waste at Hanford, research-scale melter (RSM) experiments were conducted to determine feed processing characteristics of two potential privatization Phase 1 high-level waste glass formulations and to determine if increased Ag, Te, and noble metal amounts would have bad effects. Effects of feed compositions and process conditions were examined for processing rate, cold cap behavior, off-gas, and glass properties. The 2 glass formulations used were: NOM-2 with adjusted waste loading (all components except silica and soda) of 25 wt%, and NOM-3 (max waste loaded glass) with adjusted waste loading of 30 wt%. The 25 wt% figure is the minimum required in the privatization Request for Proposal. RSM operated for 19 days (5 runs). 1010 kg feed was processed, producing 362 kg glass. Parts of runs 2 and 3 were run at 10 to 30 degrees above the nominal temperature 1150 C, with the most significant processing rate increase in run 3. Processing observations led to the choice of NOM-3 for noble metal testing in runs 4 and 5. During noble metal testing, processing rates fell 50% from baseline. Destructive analysis showed that a layer of noble metals and noble metal oxides settled on the floor of the melter, leading to current ``channeling`` which allowed the top section to cool, reducing production rates.

Feed process studies: Research-Scale Melter

International Nuclear Information System (INIS)

Whittington, K.F.; Seiler, D.K.; Luey, J.; Vienna, J.D.; Sliger, W.A.

1996-09-01

In support of a two-phase approach to privatizing the processing of hazardous and radioactive waste at Hanford, research-scale melter (RSM) experiments were conducted to determine feed processing characteristics of two potential privatization Phase 1 high-level waste glass formulations and to determine if increased Ag, Te, and noble metal amounts would have bad effects. Effects of feed compositions and process conditions were examined for processing rate, cold cap behavior, off-gas, and glass properties. The 2 glass formulations used were: NOM-2 with adjusted waste loading (all components except silica and soda) of 25 wt%, and NOM-3 (max waste loaded glass) with adjusted waste loading of 30 wt%. The 25 wt% figure is the minimum required in the privatization Request for Proposal. RSM operated for 19 days (5 runs). 1010 kg feed was processed, producing 362 kg glass. Parts of runs 2 and 3 were run at 10 to 30 degrees above the nominal temperature 1150 C, with the most significant processing rate increase in run 3. Processing observations led to the choice of NOM-3 for noble metal testing in runs 4 and 5. During noble metal testing, processing rates fell 50% from baseline. Destructive analysis showed that a layer of noble metals and noble metal oxides settled on the floor of the melter, leading to current ''channeling'' which allowed the top section to cool, reducing production rates

Noble metal (NM) behavior during simulated HLLW vitrification in induction melter with cold crucible

International Nuclear Information System (INIS)

Demin, A.V.; Matyunin, Y.I.; Fedorova, M.I.

1995-01-01

The investigation of noble metal (Ru, Rh, Pd) properties in, glass melts are connected with their specific behaviors during HLLW vitrification. Ruthenium, rhodium and palladium volatilities and heterogeneous platinoid phases forming on melts are investigated in reasonable details conformably to Joule's heating ceramic melters. The vitrification conditions in melters with induction heating of melts are differ from the vitrification ones in ceramic melters on some numbers of parameters (the availability of significant temperature gradients and convection flows in melts, short time of molten mass updating in melter and probability of definite interaction between high-frequency field and melt inhomogeneities). The results of simulated HLLW solidification modelling of the vitrification process in induction melter with cold crucible to produce phosphate and boron-silicate materials are presented. The properties of received glasses and behavior of platinoids are shown to have analogies and distinctions in comparison with compounds, synthesized in ceramic melter. The structures of dispersed particles of NM heterogeneous phases forming in glass melts prepared in induction melter with cold crucible are identified. The results of investigations show, that the marked distinctions between two processes can influence (in definite degree) as on property of synthesized materials, as on behavior of platinoid during vitrifications

Small-Scale High Temperature Melter-1 (SSHTM-1) Data Package. Appendix B

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-03-01

This appendix provides the data for Alternate HTM Flowsheet 2 (Glycolic Acid) melter feed preparation activities in both the laboratory- and small-scale testing. The first section provides an outline of this appendix. The melter feed preparation data are presented in the next two main sections, laboratory melter feed preparation data and small-scale melter feed preparation data. Section 3.0 provides the laboratory data which is discussed in the main body of the Small-Scale High Temperature-1 (SSHTM-1) Data Package, milestone C95-02.02Y. Section 3.1 gives the flowsheet in outline form as used in the laboratory-scale tests. This section also includes the ``Laboratory Melter Feed Preparation Activity Log`` which gives A chronological account of the test in terms of time, temperature, slurry pH, and specific observations about slurry appearance, acid addition rates, and samples taken. The ``Laboratory Melter Feed Preparation Activity Log`` provides a road map to the reader by which all the activity and data from the laboratory can be easily accessed. A summary of analytical data is presented next, section 3.2, which covers starting materials and progresses to the analysis of the melter feed. The next section, 3.3, characterizes the off-gas generation that occurs during the slurry processing. The following section, 3.4, provides the rheology data gathered including gram waste oxide loading information for the various slurries tested. The final section, 3.5, includes data from standard crucible redox testing. Section 4.0 provides the small-scale data in parallel form to section 3.0. Section 5.0 concludes with the references for this appendix.

Melter feed viscosity during conversion to glass: Comparison between low-activity waste and high-level waste feeds

Energy Technology Data Exchange (ETDEWEB)

Jin, Tongan [Pacific Northwest National Laboratory, Richland Washington; Chun, Jaehun [Pacific Northwest National Laboratory, Richland Washington; Dixon, Derek R. [Pacific Northwest National Laboratory, Richland Washington; Kim, Dongsang [Pacific Northwest National Laboratory, Richland Washington; Crum, Jarrod V. [Pacific Northwest National Laboratory, Richland Washington; Bonham, Charles C. [Pacific Northwest National Laboratory, Richland Washington; VanderVeer, Bradley J. [Pacific Northwest National Laboratory, Richland Washington; Rodriguez, Carmen P. [Pacific Northwest National Laboratory, Richland Washington; Weese, Brigitte L. [Pacific Northwest National Laboratory, Richland Washington; Schweiger, Michael J. [Pacific Northwest National Laboratory, Richland Washington; Kruger, Albert A. [U.S. Department of Energy, Office of River Protection, Richland Washington; Hrma, Pavel [Pacific Northwest National Laboratory, Richland Washington

2017-12-07

During nuclear waste vitrification, a melter feed (generally a slurry-like mixture of a nuclear waste and various glass forming and modifying additives) is charged into the melter where undissolved refractory constituents are suspended together with evolved gas bubbles from complex reactions. Knowledge of flow properties of various reacting melter feeds is necessary to understand their unique feed-to-glass conversion processes occurring within a floating layer of melter feed called a cold cap. The viscosity of two low-activity waste (LAW) melter feeds were studied during heating and correlated with volume fractions of undissolved solid phase and gas phase. In contrast to the high-level waste (HLW) melter feed, the effects of undissolved solid and gas phases play comparable roles and are required to represent the viscosity of LAW melter feeds. This study can help bring physical insights to feed viscosity of reacting melter feeds with different compositions and foaming behavior in nuclear waste vitrification.

Melter operation results in chemical test at Rokkasho Reprocessing Plant

International Nuclear Information System (INIS)

Kanehira, Norio; Yoshioka, Masahiro; Muramoto, Hitoshi; Oba, Takaaki; Takahashi, Yuji

2005-01-01

Chemical Test of the glass melter system of the Vitrification Facility at Rokkasho Reprocessing Plant (RRP) was performed. In this test, basic performance of heating-up of the melter, melting glass, pouring glass was confirmed using simulated materials. Through these tests and operation of all modes, good results were gained, and training of operators was completed. (author)

MODELING THE IMPACT OF ELEVATED MERCURY IN DEFENSE WASTE PROCESSING FACILITY MELTER FEED ON THE MELTER OFF-GAS SYSTEM-PRELIMINARY REPORT

Energy Technology Data Exchange (ETDEWEB)

Zamecnik, J.; Choi, A.

2010-08-18

The Defense Waste Processing Facility (DWPF) is currently evaluating an alternative Chemical Process Cell (CPC) flowsheet to increase throughput. It includes removal of the steam-stripping step, which would significantly reduce the CPC processing time and lessen the sampling needs. However, its downside would be to send 100% of the mercury that comes in with the sludge straight to the melter. For example, the new mercury content in the Sludge Batch 5 (SB5) melter feed is projected to be 25 times higher than that in the SB4 with nominal steam stripping of mercury. This task was initiated to study the impact of the worst-case scenario of zero-mercury-removal in the CPC on the DWPF melter offgas system. It is stressed that this study is intended to be scoping in nature, so the results presented in this report are preliminary. In order to study the impact of elevated mercury levels in the feed, it is necessary to be able to predict how mercury would speciate in the melter exhaust under varying melter operating conditions. A homogeneous gas-phase oxidation model of mercury by chloride was developed to do just that. The model contains two critical parameters pertaining to the partitioning of chloride among HCl, Cl, Cl{sub 2}, and chloride salts in the melter vapor space. The values for these parameters were determined at two different melter vapor space temperatures by matching the calculated molar ratio of HgCl (or Hg{sub 2}Cl{sub 2}) to HgCl{sub 2} with those measured during the Experimental-Scale Ceramic Melter (ESCM) tests run at the Pacific Northwest National Laboratory (PNNL). The calibrated model was then applied to the SB5 simulant used in the earlier flowsheet study with an assumed mercury stripping efficiency of zero; the molar ratio of Cl-to-Hg in the resulting melter feed was only 0.4, compared to 12 for the ESCM feeds. The results of the model run at the indicated melter vapor space temperature of 650 C (TI4085D) showed that due to excessive shortage of

Modeling The Impact Of Elevated Mercury In Defense Waste Processing Facility Melter Feed On The Melter Off-Gas System - Preliminary Report

International Nuclear Information System (INIS)

Zamecnik, J.; Choi, A.

2009-01-01

The Defense Waste Processing Facility (DWPF) is currently evaluating an alternative Chemical Process Cell (CPC) flowsheet to increase throughput. It includes removal of the steam-stripping step, which would significantly reduce the CPC processing time and lessen the sampling needs. However, its downside would be to send 100% of the mercury that come in with the sludge straight to the melter. For example, the new mercury content in the Sludge Batch 5 (SB5) melter feed is projected to be 25 times higher than that in the SB4 with nominal steam stripping of mercury. This task was initiated to study the impact of the worst-case scenario of zero-mercury-removal in the CPC on the DWPF melter off-gas system. It is stressed that this study is intended to be scoping in nature, so the results presented in this report are preliminary. In order to study the impact of elevated mercury levels in the feed, it is necessary to be able to predict how mercury would speciate in the melter exhaust under varying melter operating conditions. A homogeneous gas-phase oxidation model of mercury by chloride was developed to do just that. The model contains two critical parameters pertaining to the partitioning of chloride among HCl, Cl, Cl 2 , and chloride salts in the melter vapor space. The values for these parameters were determined at two different melter vapor space temperatures by matching the calculated molar ratio of HgCl (or Hg 2 Cl 2 ) to HgCl 2 with those measured during the Experimental-Scale Ceramic Melter (ESCM) tests run at the Pacific Northwest National Laboratory (PNNL). The calibrated model was then applied to the SB5 simulant used in the earlier flowsheet study with an assumed mercury stripping efficiency of zero; the molar ratio of Cl-to-Hg in the resulting melter feed was only 0.4, compared to 12 for the ESCM feeds. The results of the model run at the indicated melter vapor space temperature of 650 C (TI4085D) showed that due to excessive shortage of chloride, only 6% of

Preliminary Analysis of Species Partitioning in the DWPF Melter

Energy Technology Data Exchange (ETDEWEB)

Choi, A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Kesterson, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Johnson, F. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); McCabe, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-07-15

The work described in this report is preliminary in nature since its goal was to demonstrate the feasibility of estimating the off-gas entrainment rates from the Defense Waste Processing Facility (DWPF) melter based on a simple mass balance using measured feed and glass pour stream compositions and timeaveraged melter operating data over the duration of one canister-filling cycle. The only case considered in this study involved the SB6 pour stream sample taken while Canister #3472 was being filled over a 20-hour period on 12/20/2010, approximately three months after the bubblers were installed. The analytical results for that pour stream sample provided the necessary glass composition data for the mass balance calculations. To estimate the “matching” feed composition, which is not necessarily the same as that of the Melter Feed Tank (MFT) batch being fed at the time of pour stream sampling, a mixing model was developed involving three preceding MFT batches as well as the one being fed at that time based on the assumption of perfect mixing in the glass pool but with an induction period to account for the process delays involved in the calcination/fusion step in the cold cap and the melter turnover.

High-level waste melter alternatives assessment report

Energy Technology Data Exchange (ETDEWEB)

Calmus, R.B.

1995-02-01

This document describes the Tank Waste Remediation System (TWRS) High-Level Waste (HLW) Program`s (hereafter referred to as HLW Program) Melter Candidate Assessment Activity performed in fiscal year (FY) 1994. The mission of the TWRS Program is to store, treat, and immobilize highly radioactive Hanford Site waste (current and future tank waste and encapsulated strontium and cesium isotopic sources) in an environmentally sound, safe, and cost-effective manner. The goal of the HLW Program is to immobilize the HLW fraction of pretreated tank waste into a vitrified product suitable for interim onsite storage and eventual offsite disposal at a geologic repository. Preparation of the encapsulated strontium and cesium isotopic sources for final disposal is also included in the HLW Program. As a result of trade studies performed in 1992 and 1993, processes planned for pretreatment of tank wastes were modified substantially because of increasing estimates of the quantity of high-level and transuranic tank waste remaining after pretreatment. This resulted in substantial increases in needed vitrification plant capacity compared to the capacity of original Hanford Waste Vitrification Plant (HWVP). The required capacity has not been finalized, but is expected to be four to eight times that of the HWVP design. The increased capacity requirements for the HLW vitrification plant`s melter prompted the assessment of candidate high-capacity HLW melter technologies to determine the most viable candidates and the required development and testing (D and T) focus required to select the Hanford Site HLW vitrification plant melter system. An assessment process was developed in early 1994. This document describes the assessment team, roles of team members, the phased assessment process and results, resulting recommendations, and the implementation strategy.

High-level waste melter alternatives assessment report

International Nuclear Information System (INIS)

Calmus, R.B.

1995-02-01

This document describes the Tank Waste Remediation System (TWRS) High-Level Waste (HLW) Program's (hereafter referred to as HLW Program) Melter Candidate Assessment Activity performed in fiscal year (FY) 1994. The mission of the TWRS Program is to store, treat, and immobilize highly radioactive Hanford Site waste (current and future tank waste and encapsulated strontium and cesium isotopic sources) in an environmentally sound, safe, and cost-effective manner. The goal of the HLW Program is to immobilize the HLW fraction of pretreated tank waste into a vitrified product suitable for interim onsite storage and eventual offsite disposal at a geologic repository. Preparation of the encapsulated strontium and cesium isotopic sources for final disposal is also included in the HLW Program. As a result of trade studies performed in 1992 and 1993, processes planned for pretreatment of tank wastes were modified substantially because of increasing estimates of the quantity of high-level and transuranic tank waste remaining after pretreatment. This resulted in substantial increases in needed vitrification plant capacity compared to the capacity of original Hanford Waste Vitrification Plant (HWVP). The required capacity has not been finalized, but is expected to be four to eight times that of the HWVP design. The increased capacity requirements for the HLW vitrification plant's melter prompted the assessment of candidate high-capacity HLW melter technologies to determine the most viable candidates and the required development and testing (D and T) focus required to select the Hanford Site HLW vitrification plant melter system. An assessment process was developed in early 1994. This document describes the assessment team, roles of team members, the phased assessment process and results, resulting recommendations, and the implementation strategy

Literature review: Assessment of DWPF melter and melter off-gas system lifetime

Energy Technology Data Exchange (ETDEWEB)

Reigel, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-07-30

A glass melter for use in processing radioactive waste is a challenging environment for the materials of construction (MOC) resulting from a combination of high temperatures, chemical attack, and erosion/corrosion; therefore, highly engineered materials must be selected for this application. The focus of this report is to review the testing and evaluations used in the selection of the Defense Waste Processing Facility (DWPF), glass contact MOC specifically the Monofrax® K-3 refractory and Inconel® 690 alloy. The degradation or corrosion mechanisms of these materials during pilot scale testing and in-service operation were analyzed over a range of oxidizing and reducing flowsheets; however, DWPF has primarily processed a reducing flowsheet (i.e., Fe²⁺/ΣFe of 0.09 to 0.33) since the start of radioactive operations. This report also discusses the materials selection for the DWPF off-gas system and the corrosion evaluation of these materials during pilot scale testing and non-radioactive operations of DWPF Melter #1. Inspection of the off-gas components has not been performed during radioactive operations with the exception of maintenance because of plugging.

Literature review: Assessment of DWPF melter and melter off-gas system lifetime

Energy Technology Data Exchange (ETDEWEB)

Reigel, M. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-07-30

A glass melter for use in processing radioactive waste is a challenging environment for the materials of construction (MOC) resulting from a combination of high temperatures, chemical attack, and erosion/corrosion; therefore, highly engineered materials must be selected for this application. The focus of this report is to review the testing and evaluations used in the selection of the Defense Waste Processing Facility (DWPF), glass contact MOC specifically the Monofrax^® K-3 refractory and Inconel^® 690 alloy. The degradation or corrosion mechanisms of these materials during pilot scale testing and in-service operation were analyzed over a range of oxidizing and reducing flowsheets; however, DWPF has primarily processed a reducing flowsheet (i.e., Fe²⁺/ΣFe of 0.09 to 0.33) since the start of radioactive operations. This report also discusses the materials selection for the DWPF off-gas system and the corrosion evaluation of these materials during pilot scale testing and non-radioactive operations of DWPF Melter #1. Inspection of the off-gas components has not been performed during radioactive operations with the exception of maintenance because of plugging.

Evaluation of melter technologies for vitrification of Hanford site low-level tank waste - phase 1 testing summary report

Energy Technology Data Exchange (ETDEWEB)

Wilson, C.N., Westinghouse Hanford

1996-06-27

Following negotiation of the fourth amendment to the Tri- Party Agreement for Hanford Site cleanup, commercially available melter technologies were tested during 1994 and 1995 for vitrification of the low-level waste (LLW) stream to be derived from retrieval and pretreatment of the radioactive defense wastes stored in 177 underground tanks. Seven vendors were selected for Phase 1 testing to demonstrate vitrification of a high-sodium content liquid LLW simulant. The tested melter technologies included four Joule-heated melters, a carbon electrode melter, a combustion melter, and a plasma melter. Various dry and slurry melter feed preparation processes also were tested. The technologies and Phase 1 testing results were evaluated and a preliminary technology down-selection completed. This report describes the Phase 1 LLW melter vendor testing and the tested technologies, and summarizes the testing results and the preliminary technology recommendations.

Technical devices of powered roof support for the top coal caving as automation objects

Science.gov (United States)

Nikitenko, M. S.; Kizilov, S. A.; Nikolaev, P. I.; Kuznetsov, I. S.

2018-05-01

In the paper technical devices for the top coal caving as automation objects in the composition of the longwall mining complex (LTCC) are considered. The proposed concept for automation of the top coal caving process allows caving efficiency to be ensured, coal dilution to be prevented, conveyor overloading to be prevented, the shearer service personnel to be unloaded, the influence of the “human factor” to be reduced.

Savannah River Laboratory's operating experience with glass melters

International Nuclear Information System (INIS)

Brown, F.H.; Randall, C.T.; Cosper, M.B.; Moseley, J.P.

1982-01-01

The Department of Energy, with recommendations from the Du Pont Company, is proposing that a Defense Waste Processing Facility be constructed at the Savannah River Plant to immobilize radioactive The immobilization process is designed around the solidification of waste sludge in borosilicate glass. The Savannah River Laboratory, who is responsible for the solidification process development program, has completed an experimental program with one large-scale glass melter and just started up another melter. Experimental data indicate that process requirements can easily be met with the current design. 7 figures

Literature Review: Assessment of DWPF Melter and Melter Off-gas System Lifetime

Energy Technology Data Exchange (ETDEWEB)

Reigel, M. [Savannah River Site (SRS), Aiken, SC (United States)

2015-07-30

Testing to date for the MOC for the Hanford Waste Treatment and Immobilization Plant (WTP) melters is being reviewed with the lessons learned from DWPF in mind and with consideration to the changes in the flowsheet/feed compositions that have occurred since the original testing was performed. This information will be presented in a separate technical report that identifies any potential gaps for WTP processing.

Startup of a Joule-heated glass melter with a graphite slurry

International Nuclear Information System (INIS)

Allen, T.L.; Porter, M.A.; Routt, K.R.

1984-01-01

Startup of a Joule-heated glass melter using a graphite slurry as a conducting medium was demonstrated. This technique can be used for the initial startup and for the restart of a melter used for vitrifying high-level radioactive waste. Theory, physical property data, and a demonstration test are reported

Melter development needs assessment for RWMC buried wastes

International Nuclear Information System (INIS)

Donaldson, A.D.; Carpenedo, R.J.; Anderson, G.L.

1992-02-01

This report presents a survey and initial assessment of the existing state-of-the-art melter technology necessary to thermally treat (stabilize) buried TRU waste, by producing a highly leach resistant glass/ceramic waste form suitable for final disposal. Buried mixed transuranic (TRU) waste at the Idaho National Engineering Laboratory (INEL) represents an environmental hazard requiring remediation. The Environmental Protection Agency (EPA) placed the INEL on the National Priorities List in 1989. Remediation of the buried TRU-contaminated waste via the CERCLA decision process is required to remove INEL from the National Priorities List. A Waste Technology Development (WTD) Preliminary Systems Design and Thermal Technologies Screening Study identified joule-heated and plasma-heated melters as the most probable thermal systems technologies capable of melting the INEL soil and waste to produce the desired final waste form [Iron-Enriched Basalt (IEB) glass/ceramic]. The work reported herein then surveys the state of existing melter technology and assesses it within the context of processing INEL buried TRU wastes and contaminated soils. Necessary technology development work is recommended

Plasma/arc melter review for vitrification of mixed wastes: Results

Energy Technology Data Exchange (ETDEWEB)

Eddy, T.L.; Soelberg, N.R.; Raivo, B.D. [MeltTran, Inc., Idaho Falls, ID (United States)

1995-12-31

In October of 1994, the Idaho Waste Treatment Program (IWTP) sponsored a workshop to review the results of a plasma/arc melter system preliminary design for treating mixed waste. Attention focused on (1) the melter design, (2) the offgas system design, and (3) the overall system design. The inclusion of feed preparation and handling systems, as well as monitoring and control systems, were considered premature until decisions regarding the melter and offgas treatment were resolved. The evaluation was based on the constraints of the transuranic-contaminated mixed waste in the Radioactive Waste Management Complex (RWMC) at the Idaho National Engineering Laboratory (INEL). Major factors are the retention of the transuranics in the basaltic slag, maintenance in a radioactive environment, reliability of components to prevent any major problems, upsets, or safety concerns, and the collection, elimination, or reduction of hazardous materials for appropriate stabilization. Several modifications were recommended by the group at large, discussed by the subcommittees, and accepted as the preferred options by the design team. Though all questions were not answered, the preferred systems for mixed waste treatment were the arc melters with graphite electrode systems with appropriate cooling which reduced maintenance and the possibility of eruptions that have occurred with plasma torches. Arc melters can also result in the minimum footprint and shielding. The preferred offgas systems were the wet/dry systems, that essentially eliminate the formation of carcinogenic compounds so they do not have to be destroyed down stream. This system also puts all of the particulate matter into one stream, instead of two.

Chronology of guitarrero cave, peru.

Science.gov (United States)

Lynch, T F; Gillespie, R; Gowlett, J A; Hedges, R E

1985-08-30

Dating by accelerator mass spectrometry of wooden artifacts, cord, and charcoal samples from Guitarrero Cave, Peru, supports the antiquity of South America's earliest textiles and other perishable remains. The new dates are consistent with those obtained from disintegration counters and leave little doubt about the integrity of the lower Preceramic layers and their early cultivars. Re-evaluation of the mode of deposition suggests that most of the remains resulted from short-term use of the cave in the eighth millennium B.C., with a possible brief human visit as early as 12,560 years ago.

Incorporating Cold Cap Behavior in a Joule-heated Waste Glass Melter Model

Energy Technology Data Exchange (ETDEWEB)

Varija Agarwal; Donna Post Guillen

2013-08-01

In this paper, an overview of Joule-heated waste glass melters used in the vitrification of high level waste (HLW) is presented, with a focus on the cold cap region. This region, in which feed-to-glass conversion reactions occur, is critical in determining the melting properties of any given glass melter. An existing 1D computer model of the cold cap, implemented in MATLAB, is described in detail. This model is a standalone model that calculates cold cap properties based on boundary conditions at the top and bottom of the cold cap. Efforts to couple this cold cap model with a 3D STAR-CCM+ model of a Joule-heated melter are then described. The coupling is being implemented in ModelCenter, a software integration tool. The ultimate goal of this model is to guide the specification of melter parameters that optimize glass quality and production rate.

LFCM [liquid-fed eramic melter] emission and off-gas system performance for feed component cesium

International Nuclear Information System (INIS)

Goles, R.W.; Andersen, C.M.

1986-09-01

Except for volatile off-gas effluents, overall adequacy of the liquid-fed ceramic melter (LFCM) system depends most upon its effectiveness in dealing with cesium. However, the mechanism responsible for melter cesium losses has proved insensitive to many LFCM operating and processing conditions. As a result, variations in inleakage, plenum temperature, feeding rate and waste loading do not significantly influence melter cesium performance. Feed composition, specifically halogen content, is the only processing variable that has had a significant effect. Due to the submicron nature of LFCM-generated aerosols, melter disengagement design features are not expected to be particularly effective in reducing cesium emission rates. For the same reason, the cesium performance of conventional quench scrubbers is quite low, being dependent only upon the magnitude of melter entrainment losses. Although a deep bed washable filter has been effective in removing submicron aerosols from the process exhaust, high performance has only been achieved under dry operating conditions. The melter's idling state does not appear to place additional demands upon the off-gas treatment system

Vectra GSI, Inc. low-level waste melter testing Phase 1 test report

Energy Technology Data Exchange (ETDEWEB)

Stegen, G.E.; Wilson, C.N.

1996-02-21

A multiphase program was initiated in 1994 to test commercially available melter technologies for the vitrification of the low-level waste (LLW) stream from defense wastes stored in underground tanks at the Hanford Site in southeastern Washington State. Vectra GSI, Inc. was one of seven vendors selected for Phase 1 of the melter demonstration tests using simulated LLW that were completed during fiscal year 1995. The attached report prepared by Vectra GSI, Inc. describes results of melter testing using slurry feed and dried feeds. Results of feed drying and prereaction tests using a fluid bed calciner and rotary dryer also are described.

Vectra GSI, Inc. low-level waste melter testing Phase 1 test report

International Nuclear Information System (INIS)

Stegen, G.E.; Wilson, C.N.

1996-01-01

A multiphase program was initiated in 1994 to test commercially available melter technologies for the vitrification of the low-level waste (LLW) stream from defense wastes stored in underground tanks at the Hanford Site in southeastern Washington State. Vectra GSI, Inc. was one of seven vendors selected for Phase 1 of the melter demonstration tests using simulated LLW that were completed during fiscal year 1995. The attached report prepared by Vectra GSI, Inc. describes results of melter testing using slurry feed and dried feeds. Results of feed drying and prereaction tests using a fluid bed calciner and rotary dryer also are described

Hanford Waste Vitrification Program process development: Melt testing subtask, pilot-scale ceramic melter experiment, run summary

International Nuclear Information System (INIS)

Nakaoka, R.K.; Bates, S.O.; Elmore, M.R.; Goles, R.W.; Perez, J.M.; Scott, P.A.; Westsik, J.H.

1996-03-01

Hanford Waste Vitrification Program (HWVP) activities for FY 1985 have included engineering and pilot-scale melter experiments HWVP-11/HBCM-85-1 and HWVP-12/PSCM-22. Major objectives designated by HWVP fo these tests were to evaluate the processing characteristics of the current HWVP melter feed during actual melter operation and establish the product quality of HW-39 borosilicate glass. The current melter feed, defined during FY 85, consists of reference feed (HWVP-RF) and glass-forming chemicals added as frit

Cave age determination

International Nuclear Information System (INIS)

Anon.

1998-01-01

To determine the age of a cave we have to determine the age of elements which were created at the same moment when the cave was. Usually a cave is dug out by infiltration of acid waters. During this alteration process rocks free some aluminium and potassium ions. In Carlsbad and Lechuguilla caves, scientists have found alunite, this aluminium and potassium sulfate can be dated by using the carbon method of age determination. (A.C.)

Electrical service and controls for Joule heating of a defense waste experimental glass melter

International Nuclear Information System (INIS)

Erickson, C.J.; Haideri, A.Q.

1983-01-01

Vitrification of radioactive liquid waste in a glass matrix is a leading candidate for long-term storage of high-level waste. This paper describes the electrical service and control system for an experimental electrically heated, nonradioactive glass melter installed at Savannah River Laboratory. Data accumulated, and design/operating experience acquired in operating this melter, are being used to design a modified melter to be installed in a processing area for use with radioactive materials

Salt ingestion caves.

Directory of Open Access Journals (Sweden)

Lundquist Charles A.

2006-01-01

Full Text Available Large vertebrate herbivores, when they find a salt-bearing layer of rock, say in a cliff face, can produce sizable voids where, overgenerations, they have removed and consumed salty rock. The cavities formed by this natural animal process constitute a uniqueclass of caves that can be called salt ingestion caves. Several examples of such caves are described in various publications. Anexample in Mississippi U.S.A., Rock House Cave, was visited by the authors in 2000. It seems to have been formed by deer orbison. Perhaps the most spectacular example is Kitum Cave in Kenya. This cave has been excavated to a length over 100 metersby elephants. An ancient example is La Cueva del Milodon in Chile, which is reported to have been excavated by the now extinctmilodon, a giant ground sloth. Still other possible examples can be cited. This class of caves deserves a careful definition. First, thecavity in rock should meet the size and other conventions of the locally accepted definition of a cave. Of course this requirement differsin detail from country to country, particularly in the matter of size. The intent is to respect the local conventions. The characteristicthat human entry is possible is judged to be a crucial property of any recognized cave definition. Second, the cavity should besignificantly the result of vertebrate animal consumption of salt-bearing rock. The defining process is that rock removed to form thecave is carried away in the digestive track of an animal. While sodium salts are expected to be the norm, other salts for which thereis animal hunger are acceptable. Also some other speleogenesis process, such as solution, should not be excluded as long as it issecondary in formation of a cave in question.

Bench-scale arc melter for R&D in thermal treatment of mixed wastes

Energy Technology Data Exchange (ETDEWEB)

Kong, P.C.; Grandy, J.D.; Watkins, A.D.; Eddy, T.L.; Anderson, G.L.

1993-05-01

A small dc arc melter was designed and constructed to run bench-scale investigations on various aspects of development for high-temperature (1,500-1,800{degrees}C) processing of simulated transuranic-contaminated waste and soil located at the Radioactive Waste Management Complex (RWMC). Several recent system design and treatment studies have shown that high-temperature melting is the preferred treatment. The small arc melter is needed to establish techniques and procedures (with surrogates) prior to using a similar melter with the transuranic-contaminated wastes in appropriate facilities at the site. This report documents the design and construction, starting and heating procedures, and tests evaluating the melter`s ability to process several waste types stored at the RWMC. It is found that a thin graphite strip provides reliable starting with initial high current capability for partially melting the soil/waste mixture. The heating procedure includes (1) the initial high current-low voltage mode, (2) a low current-high voltage mode that commences after some slag has formed and arcing dominates over the receding graphite conduction path, and (3) a predominantly Joule heating mode during which the current can be increased within the limits to maintain relatively quiescent operation. Several experiments involving the melting of simulated wastes are discussed. Energy balance, slag temperature, and electrode wear measurements are presented. Recommendations for further refinements to enhance its processing capabilities are identified. Future studies anticipated with the arc melter include waste form processing development; dissolution, retention, volatilization, and collection for transuranic and low-level radionuclides, as well as high vapor pressure metals; electrode material development to minimize corrosion and erosion; refractory corrosion and/or skull formation effects; crucible or melter geometry; metal oxidation; and melt reduction/oxidation (redox) conditions.

Modifying the rheological properties of melter feed for the Hanford Waste Vitrification Plant

International Nuclear Information System (INIS)

Blair, H.T.; McMakin, A.H.

1986-03-01

Selected high-level nuclear wastes from the Hanford Site may be vitrified in the future Hanford Waste Vitrification Plant (HWVP) by Rockwell Hanford Company, the contractor responsible for reprocessing and waste management at the Hanford Site. The Pacific Northwest Laboratory (PNL), is responsible for providing technical support for the HWVP. In this capacity, PNL performed rheological evaluations of simulated HWVP feed in order to determine which processing factors could be modified to best optimize the vitrification process. To accomplish this goal, a simulated HWVP feed was first created and characterized. Researchers then evaluated how the chemical and physical form of the glass-forming additives affected the rheological properties and melting behavior of melter feed prepared with the simulated HWVP feed. The effects of adding formic acid to the waste were also evaluated. Finally, the maximum melter feed concentration with acceptable rheological properties was determined

HLW Melter Control Strategy Without Visual Feedback VSL-12R2500-1 Rev 0

Energy Technology Data Exchange (ETDEWEB)

Kruger, A A. [Department of Energy, Office of River Protection, Richland, Washington (United States); Joseph, Innocent [The Catholic University of America, Washington, DC (United States); Matlack, Keith S. [The Catholic University of America, Washington, DC (United States); Callow, Richard A. [The Catholic University of America, Washington, DC (United States); Abramowitz, Howard [The Catholic University of America, Washington, DC (United States); Pegg, Ian L. [The Catholic University of America, Washington, DC (United States); Brandys, Marek [The Catholic University of America, Washington, DC (United States); Kot, Wing K. [The Catholic University of America, Washington, DC (United States)

2012-11-13

Plans for the treatment of high level waste (HL W) at the Hanford Tank Waste Treatment and Immobilization Plant (WTP) are based upon the inventory of the tank wastes, the anticipated performance of the pretreatment processes, and current understanding of the capability of the borosilicate glass waste form [I]. The WTP HLW melter design, unlike earlier DOE melter designs, incorporates an active glass bubbler system. The bubblers create active glass pool convection and thereby improve heat and mass transfer and increase glass melting rates. The WTP HLW melter has a glass surface area of 3.75 m{sup 2} and depth of ~ 1.1 m. The two melters in the HLW facility together are designed to produce up to 7.5 MT of glass per day at 100% availability. Further increases in HL W waste processing rates can potentially be achieved by increasing the melter operating temperature above 1150°C and by increasing the waste loading in the glass product. Increasing the waste loading also has the added benefit of decreasing the number of canisters for storage.

HLW Melter Control Strategy Without Visual Feedback VSL-12R2500-1 Rev 0

International Nuclear Information System (INIS)

Kruger, A A.; Joseph, Innocent; Matlack, Keith S.; Callow, Richard A.; Abramowitz, Howard; Pegg, Ian L.; Brandys, Marek; Kot, Wing K.

2012-01-01

Plans for the treatment of high level waste (HL W) at the Hanford Tank Waste Treatment and Immobilization Plant (WTP) are based upon the inventory of the tank wastes, the anticipated performance of the pretreatment processes, and current understanding of the capability of the borosilicate glass waste form [I]. The WTP HLW melter design, unlike earlier DOE melter designs, incorporates an active glass bubbler system. The bubblers create active glass pool convection and thereby improve heat and mass transfer and increase glass melting rates. The WTP HLW melter has a glass surface area of 3.75 m 2 and depth of ∼ 1.1 m. The two melters in the HLW facility together are designed to produce up to 7.5 MT of glass per day at 100% availability. Further increases in HL W waste processing rates can potentially be achieved by increasing the melter operating temperature above 1150°C and by increasing the waste loading in the glass product. Increasing the waste loading also has the added benefit of decreasing the number of canisters for storage

Melter Disposal Strategic Planning Document

Energy Technology Data Exchange (ETDEWEB)

BURBANK, D.A.

2000-09-25

This document describes the proposed strategy for disposal of spent and failed melters from the tank waste treatment plant to be built by the Office of River Protection at the Hanford site in Washington. It describes program management activities, disposal and transportation systems, leachate management, permitting, and safety authorization basis approvals needed to execute the strategy.

Cylindrical Induction Melter Modicon Control System

International Nuclear Information System (INIS)

Weeks, G.E.

1998-04-01

In the last several years an extensive R ampersand D program has been underway to develop a vitrification system to stabilize Americium (Am) and Curium (Cm) inventories at SRS. This report documents the Modicon control system designed for the 3 inch Cylindrical Induction Melter (CIM)

PHYSICAL CHARACTERIZATION OF VITREOUS STATE LABORATORY AY102/C106 AND AZ102 HIGH LEVEL WASTE MELTER FEED SIMULANTS (U)

Energy Technology Data Exchange (ETDEWEB)

Hansen, E

2005-03-31

The objective of this task is to characterize and report specified physical properties and pH of simulant high level waste (HLW) melter feeds (MF) processed through the scaled melters at Vitreous State Laboratories (VSL). The HLW MF simulants characterized are VSL AZ102 straight hydroxide melter feed, VSL AZ102 straight hydroxide rheology adjusted melter feed, VSL AY102/C106 straight hydroxide melter feed, VSL AY102/C106 straight hydroxide rheology adjusted melter feed, and Savannah River National Laboratory (SRNL) AY102/C106 precipitated hydroxide processed sludge blended with glass former chemicals at VSL to make melter feed. The physical properties and pH were characterized using the methods stated in the Waste Treatment Plant (WTP) characterization procedure (Ref. 7).

Selection of melter systems for the DOE/Industrial Center for Waste Vitrification Research

International Nuclear Information System (INIS)

Bickford, D.F.

1993-01-01

The EPA has designated vitrification as the best developed available technology for immobilization of High-Level Nuclear Waste. In a recent federal facilities compliance agreement between the EPA, the State of Washington, and the DOE, the DOE agreed to vitrify all of the Low Level Radioactive Waste resulting from processing of High Level Radioactive Waste stored at the Hanford Site. This is expected to result in the requirement of 100 ton per day Low Level Radioactive Waste melters. Thus, there is increased need for the rapid adaptation of commercial melter equipment to DOE's needs. DOE has needed a facility where commercial pilot scale equipment could be operated on surrogate (non-radioactive) simulations of typical DOE waste streams. The DOE/Industry Center for Vitrification Research (Center) was established in 1992 at the Clemson University Department of Environmental Systems Engineering, Clemson, SC, to address that need. This report discusses some of the characteristics of the melter types selected for installation of the Center. An overall objective of the Center has been to provide the broadest possible treatment capability with the minimum number of melter units. Thus, units have been sought which have broad potential application, and which had construction characteristics which would allow their adaptation to various waste compositions, and various operating conditions, including extreme variations in throughput, and widely differing radiological control requirements. The report discusses waste types suitable for vitrification; technical requirements for the application of vitrification to low level mixed wastes; available melters and systems; and selection of melter systems. An annotated bibliography is included

Selection of melter systems for the DOE/Industrial Center for Waste Vitrification Research

Energy Technology Data Exchange (ETDEWEB)

Bickford, D.F.

1993-12-31

The EPA has designated vitrification as the best developed available technology for immobilization of High-Level Nuclear Waste. In a recent federal facilities compliance agreement between the EPA, the State of Washington, and the DOE, the DOE agreed to vitrify all of the Low Level Radioactive Waste resulting from processing of High Level Radioactive Waste stored at the Hanford Site. This is expected to result in the requirement of 100 ton per day Low Level Radioactive Waste melters. Thus, there is increased need for the rapid adaptation of commercial melter equipment to DOE`s needs. DOE has needed a facility where commercial pilot scale equipment could be operated on surrogate (non-radioactive) simulations of typical DOE waste streams. The DOE/Industry Center for Vitrification Research (Center) was established in 1992 at the Clemson University Department of Environmental Systems Engineering, Clemson, SC, to address that need. This report discusses some of the characteristics of the melter types selected for installation of the Center. An overall objective of the Center has been to provide the broadest possible treatment capability with the minimum number of melter units. Thus, units have been sought which have broad potential application, and which had construction characteristics which would allow their adaptation to various waste compositions, and various operating conditions, including extreme variations in throughput, and widely differing radiological control requirements. The report discusses waste types suitable for vitrification; technical requirements for the application of vitrification to low level mixed wastes; available melters and systems; and selection of melter systems. An annotated bibliography is included.

Computer modeling of ceramic melters to assess impacts of process and design variables on performance

International Nuclear Information System (INIS)

Eyler, L.L.; Elliott, M.L.; Lowery, P.S.; Lessor, D.L.

1991-01-01

Numerical and physical simulation of existing and advanced melter designs conducted to assess impacts of process and design variables on performance of ceramic melters are presented. Coupled equations of flow, thermal, and electric fields were numerically solved in time-dependent three dimensional finite volume form. Recent simulation results of a three electrode melter design with sloped walls indicate the presence of bi-modal stable flow patterns dominated by boundary conditions

A world review of fungi, yeasts, and slime molds in caves

Directory of Open Access Journals (Sweden)

McAlpine Donald F.

2013-01-01

Full Text Available We provide a review of fungi, yeasts, and slime molds that have been found in natural solution caves and mines worldwide. Such habitats provide frequent roost sites for bats, and in eastern North America the environmental conditions that support white-nose syndrome, a lethal fungal disease currently devastating bat populations. A list of 1029 species of fungi, slime moulds, and yeasts in 518 genera have been documented from caves and mines worldwide in 225 articles. Ascomycota dominate the cave environment. Most research has been conducted in temperate climates, especially in Europe. A mean of 17.9±24.4SD fungal species are reported per study. Questions remain about the origin and ecological roles of fungi in caves, and which, if any, are cave-specialists. In the northern hemisphere, caves are generally characterized by relatively stable, low temperatures and a lack of organic substrates. This environment favors communities of oligotrophic, psychrotolerant fungi. Data that may help explain how cave environmental features and faunas inf luence the introduction and transmission of cave fungi remains scant.

Results of a pilot scale melter test to attain higher production rates

International Nuclear Information System (INIS)

Elliott, M.L.; Perez, J.M. Jr.; Chapman, C.C.

1991-01-01

A pilot-scale melter test was completed as part of the effort to enhance glass production rates. The experiment was designed to evaluate the effects of bulk glass temperature and feed oxide loading. The maximum glass production rate obtained, 86 kg/hr-m 2 , was over 200% better than the previous record for the melter used

Temperature control system for liquid-fed ceramic melters

International Nuclear Information System (INIS)

Westsik, J.H. Jr.

1986-10-01

A temperature-feedback system has been developed for controlling electrical power to liquid-fed ceramic melters (LFCM). Software, written for a microcomputer-based data acquisition and process monitoring system, compares glass temperatures with a temperature setpoint and adjusts the electrical power accordingly. Included in the control algorithm are steps to reject failed thermocouples, spatially average the glass temperatures, smooth the averaged temperatures over time using a digital filter, and detect foaming in the glass. The temperature control system has proved effective during all phases of melter operation including startup, steady operation, loss of feed, and shutdown. This system replaces current, power, and resistance feedback control systems used previously in controlling the LFCM process

Magnetic Susceptibility and Heavy Metals in Guano from South Sulawesi Caves

Science.gov (United States)

Rifai, H.; Putra, R.; Fadila, M. R.; Erni, E.; Wurster, C. M.

2018-04-01

Measurement of some magnetic properties have been performed on vertical profile from South Sulawesi caves (Mampu and Bubau) by using low cost, rapid, sensitive and non destructive magnetic method. The aim is to attempt to use magnetic characters as a fingerprint for anthropogenic pollution in the caves. Guano samples were collected every 5 cm at a certain section of Mampu and Bubau cave, South Sulawesi, starting from surface through 300 cm in depth of mampu Cave and 30 cm of Bubau Cave. The magnetic parameters such as magnetic susceptibility and percentage frequency dependence susceptibility were measured using the Bartington MS2-MS2B instruments and supported by X-Ray Fluoroscence (XRF) to know their element composition. The results show that the samples had variations in magnetic susceptibility from 3.5 to 242.6 x 10‑8 m3/kg for Mampu Cave and from 8.6 to 106.5 x 10‑8 m3/kg for Bubau Cave and also magnetic domain. Then, the XRF results show that the caves contain several heavy metals. Magnetic and heavy metal analyses showing that the magnetic minerals in caves are lithogenic (Fe-bearing minerals) in origin and anthropogenic (Zn content) in the caves.

The Production of Advanced Glass Ceramic HLW Forms using Cold Crucible Induction Melter

Energy Technology Data Exchange (ETDEWEB)

Veronica J Rutledge; Vince Maio

2013-10-01

Cold Crucible Induction Melters (CCIMs) will favorably change how High-Level radioactive Waste (from nuclear fuel recovery) is treated in the 21st century. Unlike the existing Joule-Heated Melters (JHMs) currently in operation for the glass-based immobilization of High-Level Waste (HLW), CCIMs offer unique material features that will increase melt temperatures, increase throughput, increase mixing, increase loading in the waste form, lower melter foot prints, eliminate melter corrosion and lower costs. These features not only enhance the technology for producing HLW forms, but also provide advantageous attributes to the waste form by allowing more durable alternatives to glass. This paper discusses advantageous features of the CCIM, with emphasis on features that overcome the historical issues with the JHMs presently utilized, as well as the benefits of glass ceramic waste forms over borosilicate glass waste forms. These advantages are then validated based on recent INL testing to demonstrate a first-of-a-kind formulation of a non-radioactive ceramic-based waste form utilizing a CCIM.

Nuclear waste glass melter: an update of technical progress

International Nuclear Information System (INIS)

Brouns, R.A.; Hanson, M.S.

1984-08-01

The direct slurry-fed ceramic-lined melter is currently the reference US process for treating defense and civilian high-level liquid waste. Extensive nonradioactive pilot-scale testing at Pacific Northwest Laboratory (PNL) and Savannah River Laboratory has proven the process, defined operating parameters, and identified successful equipment design concepts. Programs at PNL continue to support several of the planned US vitrification plants through preparation of equipment designs and flowsheet testing. Current emphasis is on remotization of equipment, radioactive verification testing, and resolution of remaining technical issues. Development of this technology, technical status, and planned development activities are discussed. 9 references, 4 figures

Yield Stress Reduction of DWPF Melter Feed Slurries

International Nuclear Information System (INIS)

Stone, M.E.; Smith, M.E.

2007-01-01

The Defense Waste Processing Facility (DWPF) at the Savannah River Site vitrifies High Level Waste for repository internment. The process consists of three major steps: waste pretreatment, vitrification, and canister decontamination/sealing. The HLW consists of insoluble metal hydroxides and soluble sodium salts. The pretreatment process acidifies the sludge with nitric and formic acids, adds the glass formers as glass frit, then concentrates the resulting slurry to approximately 50 weight percent (wt%) total solids. This slurry is fed to the joule-heated melter where the remaining water is evaporated followed by calcination of the solids and conversion to glass. The Savannah River National Laboratory (SRNL) is currently assisting DWPF efforts to increase throughput of the melter. As part of this effort, SRNL has investigated methods to increase the solids content of the melter feed to reduce the heat load required to complete the evaporation of water and allow more of the energy available to calcine and vitrify the waste. The process equipment in the facility is fixed and cannot process materials with high yield stresses, therefore increasing the solids content will require that the yield stress of the melter feed slurries be reduced. Changing the glass former added during pretreatment from an irregularly shaped glass frit to nearly spherical beads was evaluated. The evaluation required a systems approach which included evaluations of the effectiveness of beads in reducing the melter feed yield stress as well as evaluations of the processing impacts of changing the frit morphology. Processing impacts of beads include changing the settling rate of the glass former (which effects mixing and sampling of the melter feed slurry and the frit addition equipment) as well as impacts on the melt behavior due to decreased surface area of the beads versus frit. Beads were produced from the DWPF process frit by fire polishing. The frit was allowed to free fall through a flame

FY-97 operations of the pilot-scale glass melter to vitrify simulated ICPP high activity sodium-bearing waste

International Nuclear Information System (INIS)

Musick, C.A.

1997-11-01

A 3.5 liter refractory-lined joule-heated glass melter was built to test the applicability of electric melting to vitrify simulated high activity waste (HAW). The HAW streams result from dissolution and separation of Idaho Chemical Processing Plant (ICPP) calcines and/or radioactive liquid waste. Pilot scale melter operations will establish selection criteria needed to evaluate the application of joule heating to immobilize ICPP high activity waste streams. The melter was fabricated with K-3 refractory walls and Inconel 690 electrodes. It is designed to be continuously operated at 1,150 C with a maximum glass output rate of 10 lbs/hr. The first set of tests were completed using surrogate HAW-sodium bearing waste (SBW). The melter operated for 57 hours and was shut down due to excessive melt temperatures resulting in low glass viscosity (< 30 Poise). Due to the high melt temperature and low viscosity the molten glass breached the melt chamber. The melter has been dismantled and examined to identify required process improvement areas and successes of the first melter run. The melter has been redesigned and is currently being fabricated for the second run, which is scheduled to begin in December 1997

High-temperature vitrification of Hanford residual-liquid waste in a continuous melter

International Nuclear Information System (INIS)

Barnes, S.M.

1980-04-01

Over 270 kg of high-temperature borosilicate glass have been produced in a series of three short-term tests in the High-Temperature Ceramic Melter vitrification system at PNL. The glass produced was formulated to vitrify simulated Hanford residual-liquid waste. The tests were designed to (1) demonstrate the feasibility of utilizing high-temperature, continuous-vitrification technology for the immobilization of the residual-liquid waste, (2) test the airlift draining technique utilized by the high-temperature melter, (3) compare glass produced in this process to residual-liquid glass produced under laboratory conditions, (4) investigate cesium volatility from the melter during waste processing, and (5) determine the maximum residual-liquid glass production rate in the high-temperature melter. The three tests with the residual-liquid composition confirmed the viability of the continuous-melting vitrification technique for the immobilization of this waste. The airlift draining technique was demonstrated in these tests and the glass produced from the melter was shown to be less porous than the laboratory-produced glass. The final glass produced from the second test was compared to a glass of the same composition produced under laboratory conditions. The comparative tests found the glasses to be indistinguishable, as the small differences in the test results fell within the precision range of the characterization testing equipment. The cesium volatility was examined in the final test. This examination showed that 0.44 wt % of the cesium (assumed to be cesium oxide) was volatilized, which translates to a volatilization rate of 115 mg/cm 2 -h

DWPF Melter No.2 Prototype Bus Bar Test Report

International Nuclear Information System (INIS)

Gordon, J.

2003-01-01

Characterization and performance testing of a prototype DWPF Melter No.2 Dome Heater Bus Bar are described. The prototype bus bar was designed to address the design features of the existing system which may have contributed to water leaks on Melter No.1. Performance testing of the prototype revealed significant improvement over the existing design in reduction of both bus bar and heater connection maximum temperature, while characterization revealed a few minor design and manufacturing flaws in the bar. The prototype is recommended as an improvement over the existing design. Recommendations are also made in the area of quality control to ensure that critical design requirements are met

Cryogenic cave carbonates from the Cold Wind Cave, Nízke Tatry Mountains, Slovakia: Extending the age range of cryogenic cave carbonate formation to the Saalian

Directory of Open Access Journals (Sweden)

Zak K.

2009-07-01

Full Text Available Cold Wind Cave, located at elevations ranging between 1,600 and 1,700 m a. s. l. in the main range of the Nízke Tatry Mountains(Slovakia, is linked in origin with the adjacent Dead Bats Cave. Together, these caves form a major cave system located within anarrow tectonic slice of Triassic sediments. Both caves have undergone complex multiphase development. A system of sub-horizontalcave levels characterized by large, tunnel-like corridors was formed during the Tertiary, when elevation differences surroundingthe cave were less pronounced than today. The central part of the Nízke Tatry Mountains, together with the cave systems, wasuplifted during the Neogene and Lower Pleistocene, which changed the drainage pattern of the area completely. The formation ofnumerous steep-sloped vadose channels and widespread cave roof frost shattering characterized cave development throughout theQuaternary.In the Cold Wind Cave, extensive accumulations of loose, morphologically variable crystal aggregates of secondary cave carbonateranging in size between less than 1 mm to about 35 mm was found on the surface of fallen limestone blocks. Based on the C andO stable isotope compositions of the carbonate (δ13C: 0.72 to 6.34 ‰, δ18O: –22.61 to –13.68 ‰ V-PDB and the negative relationbetween δ13C and δ18O, the carbonate crystal aggregates are interpreted as being cryogenic cave carbonate (CCC. Publishedmodels suggest the formation of CCC in slowly freezing water pools, probably on the surface of cave ice, most probably duringtransitions from stadials to interstadials. Though the formation of these carbonates is likely one of the youngest events in thesequence of formation of cave sediments of the studied caves, the 230Th/234U ages of three samples (79.7±2.3, 104.0±2.9, and180.0±6.3 ka are the oldest so far obtained for CCC in Central Europe. This is the first description of CCC formation in one caveduring two glacial periods (Saalian and Weichselian.

Recommendations for rheological testing and modelling of DWPF melter feed slurries

International Nuclear Information System (INIS)

Shadday, M.A. Jr.

1994-08-01

The melter feed in the DWPF process is a non-Newtonian slurry. In the melter feed system and the sampling system, this slurry is pumped at a wide range of flow rates through pipes of various diameters. Both laminar and turbulent flows are encountered. Good rheology models of the melter feed slurries are necessary for useful hydraulic models of the melter feed and sampling systems. A concentric cylinder viscometer is presently used to characterize the stress/strain rate behavior of the melter feed slurries, and provide the data for developing rheology models of the fluids. The slurries exhibit yield stresses, and they are therefore modelled as Bingham plastics. The ranges of strain rates covered by the viscometer tests fall far short of the entire laminar flow range, and therefore hydraulic modelling applications of the present rheology models frequently require considerable extrapolation beyond the range of the data base. Since the rheology models are empirical, this cannot be done with confidence in the validity of the results. Axial pressure drop versus flow rate measurements in a straight pipe can easily fill in the rest of the laminar flow range with stress/strain rate data. The two types of viscometer tests would be complementary, with the concentric cylinder viscometer providing accurate data at low strain rates, near the yield point if one exists, and pipe flow tests providing data at high strain rates up to and including the transition to turbulence. With data that covers the laminar flow range, useful rheological models can be developed. In the Bingham plastic model, linear behavior of the shear stress as a function of the strain rate is assumed once the yield stress is exceeded. Both shear thinning and shear thickening behavior have been observed in viscometer tests. Bingham plastic models cannot handle this non-linear behavior, but a slightly more complicated yield/power law model can

Enhancement of the life of refractories through the operational experience of plasma torch melter

Energy Technology Data Exchange (ETDEWEB)

Moon, Young Pyo [Technology Institute, Korea Radioactive waste Agency (KORAD), Daejeon (Korea, Republic of); Choi, Jaang Young [Chungnam National University, Daejeon (Korea, Republic of)

2016-06-15

The properties of wastes for melting need to be considered to minimize the maintenance of refractory and to discharge the molten slags smoothly from a plasma torch melter. When the nonflammable wastes from nuclear facilities such as concrete debris, glass, sand, etc., are melted, they become acid slags with low basicity since the chemical composition has much more acid oxides than basic oxides. A molten slag does not have good characteristics of discharge and is mainly responsible for the refractory erosion due to its low liquidity. In case of a stationary plasma torch melter with a slant tapping port on the wall, a fixed amount of molten slags remains inside of tapping hole as well as the melter inside after tapping out. Nonmetallic slags keep the temperature higher than melting point of metal because metallic slags located on the bottom of melter by specific gravity difference are simultaneously melted when dual mode plasma torch operates in transferred mode. In order to minimize the refractory erosion, the compatible refractories are selected considering the temperature inside the melter and the melting behavior of slags whether to contact or noncontact with molten slags. An acidic refractory shall not be installed in adjacent to a basic refractory for the resistibility against corrosion.

Remote Fiber Laser Cutting System for Dismantling Glass Melter - 13071

Energy Technology Data Exchange (ETDEWEB)

Mitsui, Takashi; Miura, Noriaki [IHI Corporation, 1 Shin-Nakahara-cho, Isogo-ku, Yokohama, Kanagawa (Japan); Oowaki, Katsura; Kawaguchi, Isao [IHI Inspection and Instrumentation Co., Ltd, 1 Shin-Nakahara-cho, Isogo-ku, Yokohama, Kanagawa (Japan); Miura, Yasuhiko; Ino, Tooru [Japan Nuclear Fuel Limited, 4-108, Aza Okitsuke, Oaza Obuchi, Rokkasho-Mura, Kamikita-gun, Aomori (Japan)

2013-07-01

Since 2008, the equipment for dismantling the used glass melter has been developed in High-level Liquid Waste (HLW) Vitrification Facility in the Japanese Rokkasho Reprocessing Plant (RRP). Due to the high radioactivity of the glass melter, the equipment requires a fully-remote operation in the vitrification cell. The remote fiber laser cutting system was adopted as one of the major pieces of equipment. An output power of fiber laser is typically higher than other types of laser and so can provide high-cutting performance. The fiber laser can cut thick stainless steel and Inconel, which are parts of the glass melter such as casings, electrodes and nozzles. As a result, it can make the whole of the dismantling work efficiently done for a shorter period. Various conditions of the cutting test have been evaluated in the process of developing the remote fiber cutting system. In addition, the expected remote operations of the power manipulator with the laser torch have been fully verified and optimized using 3D simulations. (authors)

Nuclear waste glass melter design including the power and control systems

International Nuclear Information System (INIS)

Chapman, C.C.

1982-01-01

An energy balance of a joule-heated nuclear waste glass melter is used to discuss the problems in the design of the melter geometry and in the specifications of the power and control systems. The relationships between geometry, electrode current density, production rate, load voltage, and load power are presented graphically. The influence of liquid feeding on the surface of the glass and the variability of nuclear waste glass on the design and control during operation is discussed. 10 refs

Sampling data summary for the ninth run of the Large Slurry Fed Melter

International Nuclear Information System (INIS)

Sabatino, D.M.

1983-01-01

The ninth experimental run of the Large Slurry Fed Melter (LSFM) was completed June 27, 1983, after 63 days of continuous operation. During the run, the various melter and off-gas streams were sampled and analyzed to determine melter material balances and to characterize off-gas emissions. Sampling methods and preliminary results were reported earlier. The emphasis was on the chemical analyses of the off-gas entrainment, deposits, and scrubber liquid. The significant sampling results from the run are summarized below: Flushing the Frit 165 with Frit 131 without bubbler agitation required 3 to 4.5 melter volumes. The off-gas cesium concentration during feeding was on the order of 36 to 56 μgCs/scf. The cesium concentration in the melter plenum (based on air in leakage only) was on the order of 110 to 210 μgCs/scf. Using <1 micron as the cut point for semivolatile material 60% of the chloride, 35% of the sodium and less than 5% of the managanese and iron in the entrainment are present as semivolatiles. A material balance on the scrubber tank solids shows good agreement with entrainment data. An overall cesium balance using LSFM-9 data and the DWPF production rate indicates an emission of 0.11 mCi/yr of cesium from the DWPF off-gas. This is a factor of 27 less than the maximum allowable 3 mCi/yr

Advanced waste form and Melter development for treatment of troublesome high-level wastes

Energy Technology Data Exchange (ETDEWEB)

Marra, James [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Kim, Dong -Sang [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Maio, Vincent [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-10-01

A number of waste components in US defense high level radioactive wastes (HLW) have proven challenging for current Joule heated ceramic melter (JHCM) operations and have limited the ability to increase waste loadings beyond already realized levels. Many of these “troublesome" waste species cause crystallization in the glass melt that can negatively impact product quality or have a deleterious effect on melter processing. Recent efforts at US Department of Energy laboratories have focused on understanding crystallization behavior within HLW glass melts and investigating approaches to mitigate the impacts of crystallization so that increases in waste loading can be realized. Advanced glass formulations have been developed to highlight the unique benefits of next-generation melter technologies such as the Cold Crucible Induction Melter (CCIM). Crystal-tolerant HLW glasses have been investigated to allow sparingly soluble components such as chromium to crystallize in the melter but pass out of the melter before accumulating.The Hanford site AZ-101 tank waste composition represents a waste group that is waste loading limited primarily due to high concentrations of Fe₂O₃ (also with high Al₂O₃ concentrations). Systematic glass formulation development utilizing slightly higher process temperatures and higher tolerance to spinel crystals demonstrated that an increase in waste loading of more than 20% could be achieved for this waste composition, and by extension higher loadings for wastes in the same group. An extended duration CCIM melter test was conducted on an AZ-101 waste simulant using the CCIM platform at the Idaho National Laboratory (INL). The melter was continually operated for approximately 80 hours demonstrating that the AZ-101 high waste loading glass composition could be readily processed using the CCIM technology. The resulting glass was close to the targeted composition and exhibited excellent durability in both

Črna Jama as a cold air trap cave within Postojna Cave, Slovenia

Science.gov (United States)

Šebela, Stanka; Turk, Janez

2017-10-01

Črna Jama is the coldest section of cave within the Postojna Cave System. Mean annual air temperatures at the Črna Jama 2 site are 5.6 °C (2015) and 5.7 °C (2016), and at the Črna Jama 3 site 7.1 °C (2015) and 7.2 (2016), whereas the mean external air temperature was 10.3 °C (2015) and 10.0 °C (2016). In Lepe Jame, the passage most heavily visited by tourists, the mean cave-air temperature is 10.7 °C (2014-2017). Črna Jama exhibits winter and summer temperature regimes. During warm periods (Tcave Tout), ventilation takes place and dense, cold, outside air sinks into Črna Jama because of the favourable cave entrance morphology. Recent Črna Jama air temperature data (2014-2017) indicate a < 0.5 °C higher temperature than that recorded in historical data since 1933. Črna Jama is the most appropriate place within the Postojna Cave System to study long-term climatic changes. There are hardly any tourist visits to the cave, and human impacts on the cave climate are essentially reduced.

Ancient lineage, young troglobites: recent colonization of caves by Nesticella spiders.

Science.gov (United States)

Zhang, Yuanyuan; Li, Shuqiang

2013-09-04

The evolution and origin of cave organisms is a recurring issue in evolutionary studies, but analyses are often hindered by the inaccessibility of caves, morphological convergence, and complex colonization processes. Here we investigated the evolutionary history of Nesticella cave spiders, which are mainly distributed in the Yunnan-Guizhou Plateau, China. With comprehensive sampling and phylogenetic and coalescent-based analyses, we investigated the tempo and mode of diversification and the origins of these troglobites. We also aimed to determine which factors have influenced the diversification of this little-known group. Coalescent-based species delimitation validated the 18 species recognized by morphological inspection and also suggested the existence of cryptic lineages. Divergence time estimates suggested that Nesticella cave spiders in the Yunnan-Guizhou Plateau constituted a monophyletic troglobite clade that originated in the middle Miocene (11.1-18.6 Ma). Although the Yunnan-Guizhou Plateau clade was composed exclusively of troglobite species, suggesting an ancient common subterranean ancestor, we favor multiple, independent cave colonizations during the Pleistocene over a single ancient cave colonization event to explain the origin of these cave faunas. The diversification of plateau Nesticella has been greatly influenced by the sequential uplift of the plateau and likely reflects multiple cave colonizations over time by epigean ancestors during Pleistocene glacial advances. We concluded that plateau cave Nesticella represent an ancient group of spiders, but with young troglobite lineages that invaded caves only recently. The absence of extant epigean relatives and nearly complete isolation among caves supported their relict status. Our work highlights the importance of comprehensive sampling for studies of subterranean diversity and the evolution of cave organisms. The existence of potentially cryptic species and the relict status of Nesticella

Final Report - Testing of Optimized Bubbler Configuration for HLW Melter VSL-13R2950-1, Rev. 0, dated 6/12/2013

Energy Technology Data Exchange (ETDEWEB)

Kruger, Albert A.; Pegg, I. L.; Callow, R. A.; Joseph, I.; Matlack, K. S.; Kot, W. K.

2013-11-13

The principal objective of this work was to determine the glass production rate increase and ancillary effects of adding more bubbler outlets to the current WTP HLW melter baseline. This was accomplished through testing on the HLW Pilot Melter (DM1200) at VSL. The DM1200 unit was selected for these tests since it was used previously with several HLW waste streams including the four tank wastes proposed for initial processing at Hanford. This melter system was also used for the development and optimization of the present baseline WTP HLW bubbler configuration for the WTP HLW melter, as well as for MACT testing for both HLW and LAW. Specific objectives of these tests were to: Conduct DM1200 melter testing with the baseline WTP bubbling configuration and as augmented with additional bubblers. Conduct DM1200 melter testing to differentiate the effects of total bubbler air flow and bubbler distribution on glass production rate and cold cap formation. Collect melter operating data including processing rate, temperatures at a variety of locations within the melter plenum space, melt pool temperature, glass melt density, and melter pressure with the baseline WTP bubbling configuration and as augmented with additional bubblers. Collect melter exhaust samples to compare particulate carryover for different bubbler configurations. Analyze all collected data to determine the effects of adding more bubblers to the WTP HLW melter to inform decisions regarding future lid re-designs. The work used a high aluminum HLW stream composition defined by ORP, for which an appropriate simulant and high waste loading glass formulation were developed and have been previously processed on the DM1200.

Production and remediation of low-sludge, simulated Purex waste glasses, 1: Effects of sludge oxide additions on melter operation

International Nuclear Information System (INIS)

Ramsey, W.G.

1993-01-01

Glass produced during the Purex 4 campaigns of the Integrated Defense Waste Processing Facility (DWPF) Melter System (IDMS) and the 774 Research Melter contained a lower fraction of sludge components than targeted by the Product Composition Control System (PCCS). Purex 4 glass was more durable than the benchmark (EA) glass, but less durable than most simulated SRS high-level waste glasses. Also, Purex 4 glass was considerably less durable than predicted by the algorithm which will be used to control production of DWPF glass. A melter run was performed using the 774 Research Melter to determine if the initial PCCS target composition determined for Purex 4 would produce acceptable glass whose durability could be accurately modeled by Hydration Thermodynamics. Reagent grade oxides and carbonates were added to Purex 4 melter feed stock to simulate a higher sludge loading. Each canister of glass produced was sampled and the composition, crystallinity, and durability was determined. This document details the melter operation and composition and crystallinity analyses

Technical information report: Plasma melter operation, reliability, and maintenance analysis

International Nuclear Information System (INIS)

Hendrickson, D.W.

1995-01-01

This document provides a technical report of operability, reliability, and maintenance of a plasma melter for low-level waste vitrification, in support of the Hanford Tank Waste Remediation System (TWRS) Low-Level Waste (LLW) Vitrification Program. A process description is provided that minimizes maintenance and downtime and includes material and energy balances, equipment sizes and arrangement, startup/operation/maintence/shutdown cycle descriptions, and basis for scale-up to a 200 metric ton/day production facility. Operational requirements are provided including utilities, feeds, labor, and maintenance. Equipment reliability estimates and maintenance requirements are provided which includes a list of failure modes, responses, and consequences

Modeling principles applied to the simulation of a joule-heated glass melter

International Nuclear Information System (INIS)

Routt, K.R.

1980-05-01

Three-dimensional conservation equations applicable to the operation of a joule-heated glass melter were rigorously examined and used to develop scaling relationships for modeling purposes. By rigorous application of the conservation equations governing transfer of mass, momentum, energy, and electrical charge in three-dimensional cylindrical coordinates, scaling relationships were derived between a glass melter and a physical model for the following independent and dependent variables: geometrical size (scale), velocity, temperature, pressure, mass input rate, energy input rate, voltage, electrode current, electrode current flux, total power, and electrical resistance. The scaling relationships were then applied to the design and construction of a physical model of the semiworks glass melter for the Defense Waste Processing Facility. The design and construction of such a model using glycerine plus LiCl as a model fluid in a one-half-scale Plexiglas tank is described

Design and performance of a 100-kg/h, direct calcine-fed electric-melter system for nuclear-waste vitrification

International Nuclear Information System (INIS)

Dierks, R.D.

1980-11-01

This report describes the physical characteristics of a ceramic-lined, joule-heated glass melter that is directly connected to the discharge of a spray calciner and is currently being used to study the vitrification of simulated nuclear-waste slurries. Melter performance characteristics and subsequent design improvements are described. The melter contains 0.24 m 3 of glass with a glass surface area of 0.76 m 2 , and is heated by the flow of an alternating current (ranging from 600 to 1200 amps) between two Inconel-690 slab-type electrodes immersed in the glass at either end of the melter tank. The melter was maintained at operating temperature (900 to 1260 0 C) for 15 months, and produced 62,000 kg of glass. The maximum sustained operating period was 122 h, during which glass was produced at the rate of 70 kg/h

Geophysical exploration in vicinity of the Unicorn Cave, South Harz Mountains, Germany

Science.gov (United States)

Kaufmann, Georg; Romanov, Douchko; Nielbock, Ralf

2010-05-01

The Unicorn Cave in the southern Harz Mountains in Germany is located in an outcrop of dolomite from the Zechstein formation, which is underlain by Grauwacke rocks. The cave, about 600 meters long, consists of several large chambers, which are connected by a gallery following the main fault alignments in E/W, NE/SW, and NW/SE direction. The overburden of the cave is shallow, between 10 and 30 m. We have used this cave site to perform a sensitivity test for both gravimetric and geoelectic methods above the cave. Additionally, geoelectic mapping has been used to assess the thickness of the cave sediments in one of the chambers. Our results show a clear signal in the Bouguer anomaly, which can only be explained by a combined model of the void space and the sediment filling. Geoelectric results are less clear, but support the gravimetry.

FINAL REPORT INTEGRATED DM1200 MELTER TESTING USING AZ 102 AND C 106/AY-102 HLW SIMULANTS: HLW SIMULANT VERIFICATION VSL-05R5800-1 REV 0 6/27/05

Energy Technology Data Exchange (ETDEWEB)

KRUGER AA; MATLACK KS; GONG W; BARDAKCI T; D' ANGELO NA; BRANDYS M; KOT WK; PEGG IL

2011-12-29

The principal objectives of the DM1200 melter tests were to determine the effects of feed rheology, feed solid content, and bubbler configuration on glass production rate and off-gas system performance while processing the HLW AZ-101 and C-106/AY-102 feed compositions; characterize melter off-gas emissions; characterize the performance of the prototypical off-gas system components, as well as their integrated performance; characterize the feed, glass product, and off-gas effluents; and perform pre- and post test inspections of system components. The specific objectives (including test success criteria) of this testing, along with how each objective was met, are outlined in a table. The data provided in this Final Report address the impacts of HLW melter feed rheology on melter throughput and validation of the simulated HLW melter feeds. The primary purpose of this testing is to further validate/verify the HLW melter simulants that have been used for previous melter testing and to support their continued use in developing melter and off-gas related processing information for the Project. The primary simulant property in question is rheology. Simulants and melter feeds used in all previous melter tests were produced by direct addition of chemicals; these feed tend to be less viscous than rheological the upper-bound feeds made from actual wastes. Data provided here compare melter processing for the melter feed used in all previous DM100 and DM1200 tests (nominal melter feed) with feed adjusted by the feed vendor (NOAH Technologies) to be more viscous, thereby simulating more closely the upperbounding feed produced from actual waste. This report provides results of tests that are described in the Test Plan for this work. The Test Plan is responsive to one of several test objectives covered in the WTP Test Specification for this work; consequently, only part of the scope described in the Test Specification was addressed in this particular Test Plan. For the purpose of

Final Report Integrated DM1200 Melter Testing Using AZ-102 And C-106/AY-102 HLW Simulants: HLW Simulant Verification VSL-05R5800-1, Rev. 0, 6/27/05

International Nuclear Information System (INIS)

Kruger, A.A.; Matlack, K.S.; Gong, W.; Bardakci, T.; D'Angelo, N.A.; Brandys, M.; Kot, W.K.; Pegg, I.L.

2011-01-01

The principal objectives of the DM1200 melter tests were to determine the effects of feed rheology, feed solid content, and bubbler configuration on glass production rate and off-gas system performance while processing the HLW AZ-101 and C-106/AY-102 feed compositions; characterize melter off-gas emissions; characterize the performance of the prototypical off-gas system components, as well as their integrated performance; characterize the feed, glass product, and off-gas effluents; and perform pre- and post test inspections of system components. The specific objectives (including test success criteria) of this testing, along with how each objective was met, are outlined in a table. The data provided in this Final Report address the impacts of HLW melter feed rheology on melter throughput and validation of the simulated HLW melter feeds. The primary purpose of this testing is to further validate/verify the HLW melter simulants that have been used for previous melter testing and to support their continued use in developing melter and off-gas related processing information for the Project. The primary simulant property in question is rheology. Simulants and melter feeds used in all previous melter tests were produced by direct addition of chemicals; these feed tend to be less viscous than rheological the upper-bound feeds made from actual wastes. Data provided here compare melter processing for the melter feed used in all previous DM100 and DM1200 tests (nominal melter feed) with feed adjusted by the feed vendor (NOAH Technologies) to be more viscous, thereby simulating more closely the upperbounding feed produced from actual waste. This report provides results of tests that are described in the Test Plan for this work. The Test Plan is responsive to one of several test objectives covered in the WTP Test Specification for this work; consequently, only part of the scope described in the Test Specification was addressed in this particular Test Plan. For the purpose of

The production of advanced glass ceramic HLW forms using cold crucible induction melter

International Nuclear Information System (INIS)

Rutledge, V.J.; Maio, V.

2013-01-01

Cold Crucible Induction Melters (CCIM) will favorably change how High-Level radioactive Waste (from nuclear fuel recovery) is treated in a near future. Unlike the existing Joule-Heated Melters (JHM) currently in operation for the glass-based immobilization of High-Level Waste (HLW), CCIM offers unique material features that will increase melt temperatures, increase throughput, increase mixing, increase loading in the waste form, lower melter foot prints, eliminate melter corrosion and lower costs. These features not only enhance the technology for producing HLW forms, but also provide advantageous attributes to the waste form by allowing more durable alternatives to glass. It is concluded that glass ceramic waste forms that are tailored to immobilize fission products of HLW can be can be made from the HLW processed with the CCIM. The advantageous higher temperatures reached with the CCIM and unachievable with JHM allows the lanthanides, alkali, alkaline earths, and molybdenum to dissolve into a molten glass. Upon controlled cooling they go into targeted crystalline phases to form a glass ceramic waste form with higher waste loadings than achievable with borosilicate glass waste forms. Natural cooling proves to be too fast for the formation of all targeted crystalline phases

Bench-scale arc melter for R ampersand D in thermal treatment of mixed wastes

International Nuclear Information System (INIS)

Kong, P.C.; Grandy, J.D.; Watkins, A.D.; Eddy, T.L.; Anderson, G.L.

1993-05-01

A small dc arc melter was designed and constructed to run bench-scale investigations on various aspects of development for high-temperature (1,500-1,800 degrees C) processing of simulated transuranic-contaminated waste and soil located at the Radioactive Waste Management Complex (RWMC). Several recent system design and treatment studies have shown that high-temperature melting is the preferred treatment. The small arc melter is needed to establish techniques and procedures (with surrogates) prior to using a similar melter with the transuranic-contaminated wastes in appropriate facilities at the site. This report documents the design and construction, starting and heating procedures, and tests evaluating the melter's ability to process several waste types stored at the RWMC. It is found that a thin graphite strip provides reliable starting with initial high current capability for partially melting the soil/waste mixture. The heating procedure includes (1) the initial high current-low voltage mode, (2) a low current-high voltage mode that commences after some slag has formed and arcing dominates over the receding graphite conduction path, and (3) a predominantly Joule heating mode during which the current can be increased within the limits to maintain relatively quiescent operation. Several experiments involving the melting of simulated wastes are discussed. Energy balance, slag temperature, and electrode wear measurements are presented. Recommendations for further refinements to enhance its processing capabilities are identified. Future studies anticipated with the arc melter include waste form processing development; dissolution, retention, volatilization, and collection for transuranic and low-level radionuclides, as well as high vapor pressure metals; electrode material development to minimize corrosion and erosion; refractory corrosion and/or skull formation effects; crucible or melter geometry; metal oxidation; and melt reduction/oxidation (redox) conditions

Cave Entrance dependent Spore Dispersion of Filamentous Fungi Isolated from Various Sediments of Iron Ore Cave in Brazil: a colloquy on human threats while caving

Directory of Open Access Journals (Sweden)

Erika Linzi Silva Taylor

2014-04-01

Full Text Available Caves are stable environments with characteristics favoring the development of fungi. The fungal community present in a cave also includes pathogenic and opportunistic species out of which some are also served as energy sources in such energy stared ecosystems. Studies on microbial diversity and their role on such energy starved ecosystem are scarce. The present study was aimed to identify the cultivable filamentous fungi present in the various sediment of an iron ore cave and to recognize them as pathogenic and/or opportunistic species. Further the impact of cave entrance on the spore depositions on various distances dependent sediments were analyzed. The results suggest a diverse microbial community inhabiting the cave and an influence of cave entrance over spore deposition on various sediments. We counted a total of 4,549 filamentous fungi that included 34 species of 12 genera: Acremonium, Aspergillus, Cladosporium, Fusarium, Geotrichum, Paecilomyces, Purpureocillium, Penicillium, Torula, Trichoderma, Mucor and Rhizopus. A positive significant relation was observed between spore deposition and distance from cave entrance (p= 0.001. Areas of potential mycoses risks were recognized. This is the first study on microbiological community of an iron ore cave in the country.

The show cave of Diros vs. wild caves of Peloponnese, Greece - distribution patterns of Cyanobacteria

Directory of Open Access Journals (Sweden)

Vasiliki Lamprinou

2014-09-01

Full Text Available The karst cave ‘Vlychada’of Diros, one of the oldest show caves in Peloponnese, sustains extended phototrophic biofilms on various substrata – on rocks inside the cave including speleothems, and especially near the artificial lighting installation (‘Lampenflora’. After a survey of the main abiotic parameters (Photosynthetically Active Radiation -PAR, Temperature -T, Relative Humidity -RH, Carbon Dioxide -CO2 three clusters of sampling sites were revealed according to Principal Component Analysis (PCA: i the water gallery section predominately influenced by CO2, ii the dry passages influenced by RH and PAR, and iii the area by the cave exit at the dry section influenced by temperature. The collected samples from the water gallery section and the dry passages of the cave revealed a total of 43 taxa of Cyanobacteria, with the unicellular/colonial forms being the most abundant. The applied non-metric Multi-dimensional Scaling Ordination (nMDS of the cumulative species composition showed a clear distinction between the water gallery section and the dry passages of the cave. Further comparison with previous data from other wild caves of Peloponnese (‘Kastria’, ‘Francthi’, and ‘Selinitsa’ was conducted revealing a distinction between the show cave and the wild ones. Apart from the human impact on cave ecosystems – through aesthetic alteration (‘greening’ of cave decorations by the ‘Lampenflora’, and by the cleaning treatments and restoration projects on the speleothems – identification of the organisms constituting the ‘Lampenflora’ might provide taxonomically and ecologically significant taxa.

Patronage and Support: Socio-Cultural Role of Kanheri Caves in the Evolving Interactions

Directory of Open Access Journals (Sweden)

Kishor Gaikwad

2010-12-01

Full Text Available A number of factors were responsible in the evolution of the first state craft in deccan locale. There were bound to be, several regional power centers beyond the main arena of Satvahna power. Their negotiation, complementing and supplementing each others need as well as with limited autonomy, enjoying their peripheral important status. Kanheri caves, specially the epigraphic evidences during Satvahna times, could be the best marker of variety of power specificities within deccan. These inscriptions made references to casts, gotras, communities, gahapaties as well as garini and kutumbini etc. These were all local social cultural forces were playing imperative roles in the larger eco-political ambiance of deccan. It's a kind of multidimensional relationship of mainstream political and cultural process, specially seprated to ecological setting. Surprisingly from these plaethora of inscriptions guilds and Satvahna royal house hold didn't carve out their space. Kanheri caves laid phenomenal role in trade and cultural interactions. The present paper as an attempt to explore socio cultural role of Kanheri caves in these interactions.

Final Report - Effects of High Spinel and Chromium Oxide Crystal Contents on Simulated HLW Vitrification in DM100 Melter Tests, VSL-09R1520-1, Rev. 0, dated 6/22/09

Energy Technology Data Exchange (ETDEWEB)

Kruger, Albert A.; Matlack, K. S.; Kot, W.; Pegg, I. L.; Chaudhuri, M.; Lutze, W.

2013-11-13

The principal objective of the work was to evaluate the effects of spinel and chromium oxide particles on WTP HLW melter operations and potential impacts on melter life. This was accomplished through a combination of crucible-scale tests, settling and rheological tests, and tests on the DM100 melter system. Crucible testing was designed to develop and identify HLW glass compositions with high waste loadings that exhibit formation of crystalline spinel and/or chromium oxide phases up to relatively high crystal contents (i.e., > 1 vol%). Characterization of crystal settling and the effects on melt rheology was performed on the HLW glass formulations. Appropriate candidate HLW glass formulations were selected, based on characterization results, to support subsequent melter tests. In the present work, crucible melts were formulated that exhibit up to about 4.4 vol% crystallization.

Analysis of cascade impactor and EPA method 29 data from the americium/curium pilot melter system

International Nuclear Information System (INIS)

Zamecnik, J.R.

1997-11-01

The offgas system of the Am/Cm pilot melter at TNX was characterized by measuring the particulate evolution using a cascade impactor and EPA Method 29. This sampling work was performed by John Harden of the Clemson Environmental Technologies Laboratory, under SCUREF Task SC0056. Elemental analyses were performed by the SRTC Mobile Laboratory.Operation of the Am/Cm melter with B2000 frit has resulted in deposition of PbO and boron compounds in the offgas system that has contributed to pluggage of the High Efficiency Mist Eliminator (HEME). Sampling of the offgas system was performed to quantify the amount of particulate in the offgas system under several sets of conditions. Particulate concentration and particle size distribution were measured just downstream of the melter pressure control air addition port and at the HEME inlet. At both locations, the particulate was measured with and without steam to the film cooler while the melter was idled at about 1450 degrees Celsius. Additional determinations were made at the melter location during feeding and during idling at 1150 degrees Celsius rather than 1450 degrees Celsius (both with no steam to the film cooler). Deposition of particulates upstream of the melter sample point may have, and most likely did occur in each run, so the particulate concentrations measured do no necessarily reflect the total particulate emission at the melt surface. However, the data may be used in a relative sense to judge the system performance

Compatibility tests of materials for a prototype ceramic melter for defense glass-waste products

International Nuclear Information System (INIS)

Wicks, G.G.

1979-01-01

Objective is to evaluate the corrosion/erosion resistance of melter materials. Materials tested were Monofrox K3 and E, Serv, Inconel 690, Pt, and SnO. Results show that Inconel 690 is the leading electrode material and Monofrox K3 the leading refractory candidate. Melter lifetime is estimated to be 2 to 5 years for defense waste

DM100 AND DM1200 MELTER TESTING WITH HIGH WASTE LOADING GLASS FORMULATIONS FOR HANFORD HIGH-ALUMINUM HLW STREAMS

Energy Technology Data Exchange (ETDEWEB)

KRUGER AA; MATLACK KS; KOT WK; PEGG IL; JOSEPH I

2009-12-30

This Test Plan describes work to support the development and testing of high waste loading glass formulations that achieve high glass melting rates for Hanford high aluminum high level waste (HLW). In particular, the present testing is designed to evaluate the effect of using low activity waste (LAW) waste streams as a source of sodium in place ofchemical additives, sugar or cellulose as a reductant, boehmite as an aluminum source, and further enhancements to waste processing rate while meeting all processing and product quality requirements. The work will include preparation and characterization of crucible melts in support of subsequent DuraMelter 100 (DM 100) tests designed to examine the effects of enhanced glass formulations, glass processing temperature, incorporation of the LAW waste stream as a sodium source, type of organic reductant, and feed solids content on waste processing rate and product quality. Also included is a confirmatory test on the HLW Pilot Melter (DM1200) with a composition selected from those tested on the DM100. This work builds on previous work performed at the Vitreous State Laboratory (VSL) for Department of Energy's (DOE's) Office of River Protection (ORP) to increase waste loading and processing rates for high-iron HLW waste streams as well as previous tests conducted for ORP on the same waste composition. This Test Plan is prepared in response to an ORP-supplied statement of work. It is currently estimated that the number of HLW canisters to be produced in the Hanford Tank Waste Treatment and Immobilization Plant (WTP) is about 12,500. This estimate is based upon the inventory ofthe tank wastes, the anticipated performance of the sludge treatment processes, and current understanding of the capability of the borosilicate glass waste form. The WTP HLW melter design, unlike earlier DOE melter designs, incorporates an active glass bubbler system. The bubblers create active glass pool convection and thereby improve heat

Vitrification of noble metals containing NCAW simulant with an engineering scale melter (ESM): Campaign report

Energy Technology Data Exchange (ETDEWEB)

Grunewald, W.; Roth, G.; Tobie, W.; Weisenburger, S.; Weiss, K.; Elliott, M.; Eyler, L.L.

1996-03-01

ESM has been designed as a 10th-scale model of the DWPF-type melter, currently the reference melter for nitrification of Hanford double shell tankwaste. ESM and related equipment have been integrated to the existing mockup vitrification plant VA-WAK at KfK. On June 2-July 10, 1992, a shakedown test using 2.61 m{sup 3} of NCAW (neutralized current acid waste) simulant without noble metals was performed. On July 11-Aug. 30, 1992, 14.23 m{sup 3} of the same simulant with nominal concentrations of Ru, Rh, and Pd were vitrified. Objective was to investigate the behavior of such a melter with respect to discharge of noble metals with routine glass pouring via glass overflow. Results indicate an accumulation of noble metals in the bottom area of the flat-bottomed ESM. About 65 wt% of the noble metals fed to the melter could be drained out, whereas 35 wt% accumulated in the melter, based on analysis of glass samples from glass pouring stream in to the canisters. After the melter was drained at the end of the campaign through a bottom drain valve, glass samples were taken from the residual bottom layer. The samples had significantly increased noble metals content (factor of 20-45 to target loading). They showed also a significant decrease of the specific electric resistance compared to bulk glass (factor of 10). A decrease of 10- 15% of the resistance between he power electrodes could be seen at the run end, but the total amount of noble metals accumulated was not yet sufficient enough to disturb the Joule heating of the glass tank severely.

Pilot-scale ceramic melter 1985-1986 rebuild: Nuclear Waste Treatment Program

International Nuclear Information System (INIS)

Koegler, S.S.

1987-07-01

The pilot-scale ceramic melter (PSCM) was subsequently dismantled, and the damaged and corroded components were repaired or replaced. The PSCM rebuild ensures that the melter will be available for an additional three to five years of planned testing. An analysis of the corrosion products and the failed electrodes indicated that the electrode bus connection welds may have failed due to a combination of chemical and mechanical effects. The electrodes were replaced with a design similar to the original electrodes, but with improved electrical bus connections. The implications of the PSCM electrode corrosion evaluation are that, although Inconel 690 has excellent corrosion resistance to molten glass, corrosion at the melt line in stagnant regions is a significant concern. Functional changes made during the rebuild included increases in wall and floor insulation to better simulate well-insulated melters, a decrease in the lid height for more prototypical plenum and off-gas conditions, and installation of an Inconel 690 trough and dam to improve glass pouring and prevent glass seepage. 9 refs., 33 figs., 5 tabs

Next Generation Melter Optioneering Study - Interim Report

International Nuclear Information System (INIS)

Gray, M.F.; Calmus, R.B.; Ramsey, G.; Lomax, J.; Allen, H.

2010-01-01

The next generation melter (NOM) development program includes a down selection process to aid in determining the recommended vitrification technology to implement into the WTP at the first melter change-out which is scheduled for 2025. This optioneering study presents a structured value engineering process to establish and assess evaluation criteria that will be incorporated into the down selection process. This process establishes an evaluation framework that will be used progressively throughout the NGM program, and as such this interim report will be updated on a regular basis. The workshop objectives were achieved. In particular: (1) Consensus was reached with stakeholders and technology providers represented at the workshop regarding the need for a decision making process and the application of the D 2 0 process to NGM option evaluation. (2) A framework was established for applying the decision making process to technology development and evaluation between 2010 and 2013. (3) The criteria for the initial evaluation in 2011 were refined and agreed with stakeholders and technology providers. (4) The technology providers have the guidance required to produce data/information to support the next phase of the evaluation process. In some cases it may be necessary to reflect the data/information requirements and overall approach to the evaluation of technology options against specific criteria within updated Statements of Work for 2010-2011. Access to the WTP engineering data has been identified as being very important for option development and evaluation due to the interface issues for the NGM and surrounding plant. WRPS efforts are ongoing to establish precisely data that is required and how to resolve this Issue. It is intended to apply a similarly structured decision making process to the development and evaluation of LAW NGM options.

Processing of high-temperature simulated waste glass in a continuous ceramic melter

International Nuclear Information System (INIS)

Barnes, S.M.; Brouns, R.A.; Hanson, M.S.

1980-01-01

Recent operations have demonstrated that high-melting-point glasses and glass-ceramics can be successfully processed in joule-heated, ceramic-lined melters with minor modifications to the existing technology. Over 500 kg of simulated waste glasses have been processed at temperatures up to 1410 0 C. The processability of the two high-temperature waste forms tested is similar to existing borosilicate waste glasses. High-temperature waste glass formulations produced in the bench-scale melter exhibit quality comparing favorably to standard waste glass formulations

Survey and hydrogeology of Carroll Cave

Science.gov (United States)

Carroll Cave, located in Camden County, Missouri, is the largest known cave formed in the Gasconade Dolomite of the Salem Plateau. Despite extensive visitation over the last 50 years and multiple survey efforts, a comprehensive map of the cave has never been produced. In 2002, the Carroll Cave Conse...

The importance of ants in cave ecology, with new records and behavioral observations of ants in Arizona caves

Directory of Open Access Journals (Sweden)

Robert B. Pape

2016-09-01

Full Text Available The importance of ants as elements in cave ecology has been mostly unrecognized. A global list of ant species recorded from caves, compiled from a review of existing literature, is presented. This paper also reviews what is currently known about ants occurring in Arizona (USA caves. The diversity and distribution represented in these records suggests ants are relatively common cave visitors (trogloxenes. A general utilization of caves by ants within both temperate and tropical latitudes may be inferred from this combined evidence. Observations of ant behavior in Arizona caves demonstrate a low level and sporadic, but persistent, use of these habitats and their contained resources by individual ant colonies. Documentation of Neivamyrmex sp. preying on cave-inhabiting arthropods is reported here for the first time. Observations of hypogeic army ants in caves suggests they may not penetrate to great vertical depth in search of prey, but can be persistent occupants in relatively shallow, horizontal sections of caves where they may prey on endemic cave animals. First cave records for ten ant species are reported from Arizona caves. These include two species of Neivamyrmex (N. nigrescens Cresson and Neivamyrmex sp.; Formicidae: Dorylinae, four myrmicines (Pheidole portalensis Wilson, Pheidole cf. porcula Wheeler, Solenopsis aurea Wheeler and Stenamma sp. Westwood, one dolichoderine (Forelius keiferi Wheeler and three formicines (Lasius arizonicus Wheeler, L. sitiens Wilson, and Camponotus sp. Mayr.

Effect of melter feed foaming on heat flux to the cold cap

Science.gov (United States)

Lee, SeungMin; Hrma, Pavel; Pokorny, Richard; Klouzek, Jaroslav; VanderVeer, Bradley J.; Dixon, Derek R.; Luksic, Steven A.; Rodriguez, Carmen P.; Chun, Jaehun; Schweiger, Michael J.; Kruger, Albert A.

2017-12-01

The glass production rate, which is crucial for the nuclear waste cleanup lifecycle, is influenced by the chemical and mineralogical nature of melter feed constituents. The choice of feed materials affects both the conversion heat and the thickness of the foam layer that forms at the bottom of the cold cap and controls the heat flow from molten glass. We demonstrate this by varying the alumina source, namely, substituting boehmite or corundum for gibbsite, in a high-alumina high-level-waste melter feed. The extent of foaming was determined using the volume expansion test and the conversion heat with differential scanning calorimetry. Evolved gas analysis was used to identify gases responsible for the formation of primary and secondary foam. The foam thickness, a critical factor in the rate of melting, was estimated using known values of heat conductivities and melting rates. The result was in reasonable agreement with the foam thickness experimentally observed in quenched cold caps from the laboratory-scale melter.

Effect of melter feed foaming on heat flux to the cold cap

Energy Technology Data Exchange (ETDEWEB)

Lee, SeungMin; Hrma, Pavel; Pokorny, Richard; Klouzek, Jaroslav; VanderVeer, Bradley J.; Dixon, Derek R.; Luksic, Steven A.; Rodriguez, Carmen P.; Chun, Jaehun; Schweiger, Michael J.; Kruger, Albert A.

2017-12-01

The glass production rate, which is crucial for the nuclear waste cleanup lifecycle, is influenced by the chemical and mineralogical nature of melter feed constituents. The choice of feed materials affects both the conversion heat and the thickness of the foam layer that forms at the bottom of the cold cap and controls the heat flow from molten glass. We demonstrate this by varying the alumina source, namely, substituting boehmite or corundum for gibbsite, in a high-alumina high-level-waste melter feed. The extent of foaming was determined using the volume expansion test and the conversion heat with differential scanning calorimetry. Evolved gas analysis was used to identify gases responsible for the formation of primary and secondary foam. The foam thickness, a critical factor in the rate of melting, was estimated using known values of heat conductivities and melting rates. The result was in reasonable agreement with the foam thickness experimentally observed in the laboratory-scale melter.

Noble metals-compatible melter features development Phase 1: Establishing functional and design criteria and design concepts

International Nuclear Information System (INIS)

Elmore, M.R.; Siemens, D.H.; Chapman, C.C.

1996-03-01

Premature failures have occurred in melters at Japan's Tokai Mockup Facility and at the Federal Republic of Germany (FRG) PAMELA plant during processing of feeds with high levels of noble metals. Melter failure was due to the accumulation of an electrically conductive, noble metals-containing precipitates in the glass, that then resulted in short circuiting of the electrodes. A comparison was made of the anticipated Hanford Waste Vitrification Plant (HWVP) feed with the feeds processed in the FRG and Japanese melters. The evaluation showed that comparable levels of noble metals and other potential precipitate-forming components (e.g. Cr/Fe/Ni-spinels) exist in the HWVP feed. As a result, the HWVP project made a decision to modify the present reference melter design to include features to prevent the precipitation and accumulation or otherwise accommodate precipitated phases on a routine basis without loss of production capacity

Exposure to radon in Cuban tourist caves

International Nuclear Information System (INIS)

Carrazana Gonzalez, Jorge; Dominguez Ley, Orlando; Gil Castillo, Reinaldo; Molerio Leon, Leslie

2008-01-01

With the objective of estimating the dose, due to Radon-222, received by tour guides and other people who work inside some of the most important tourist caves in the Republic of Cuba, measurements of radon concentrations were carried out in four of these caves: Santo Tomas Cave, Tapiada Cave, Del Indio Cave and Jose Miguel Cave. All these caves are located in the Vinales Valley (Pinar del Rio City), a very important tourist area in the country. The relationship among radon concentration, the concentration of natural radionuclides inside the caves and the geologic characteristics of the specific locations was analyzed. In order to select the most appropriates measurement places, different criteria were taken into account: representatives points of the geology of the caves, level of gamma radiation, exchange of air, places of work inside the caves (cafeterias, restaurants and shops) and places more frequently visited by tour guides. The maximum radon concentration was found in Jose Miguel Cave with a value of 220 Bq/m 3 . The measurement of gamma dose rate inside the caves was carried out with a scintillation detector type Scintrex BGS-3 previously calibrated at SSI, Sweden. The radon concentrations were measured with the equipment Alpha Guard PQ2000/MC50 and SARAD RM2000, both also calibrated at SSI, Sweden. The obtained results indicated that, in the studied caves, the annual dose is not greater than 1 mSv considering a work year of 2000 hours. (author)

Vitrification of HLW produced by uranium/molybdenum fuel reprocessing in cogema's cold crucible melter

International Nuclear Information System (INIS)

Quang, R. Do; Petitjean, V.; Hollebeque, F.; Pinet, O.; Flament, T.; Prodhomme, A.; Dalcorso, J. P.

2003-01-01

The performance of the vitrification process currently used in the La Hague commercial reprocessing plants has been continuously improved during more than ten years of operation. In parallel COGEMA (industrial Operator), the French Atomic Energy Commission (CEA) and SGN (respectively COGEMA's R and D provider and Engineering) have developed the cold crucible melter vitrification technology to obtain greater operating flexibility, increased plant availability and further reduction of secondary waste generated during operations. The cold crucible is a compact water-cooled melter in which the radioactive waste and the glass additives are melted by direct high frequency induction. The cooling of the melter produces a solidified glass layer that protects the melter's inner wall from corrosion. Because the heat is transferred directly to the melt, high operating temperatures can be achieved with no impact on the melter itself. COGEMA plans to implement the cold crucible technology to vitrify high level liquid waste from reprocessed spent U-Mo-Sn-Al fuel (used in gas cooled reactor). The cold crucible was selected for the vitrification of this particularly hard-to-process waste stream because it could not be reasonably processed in the standard hot induction melters currently used at the La Hague vitrification facilities : the waste has a high molybdenum content which makes it very corrosive and also requires a special high temperature glass formulation to obtain sufficiently high waste loading factors (12% in molybdenum). A special glass formulation has been developed by the CEA and has been qualified through lab and pilot testing to meet standard waste acceptance criteria for final disposal of the U-Mo waste. The process and the associated technologies have been also being qualified on a full-scale prototype at the CEA pilot facility in Marcoule. Engineering study has been integrated in parallel in order to take into account that the Cold Crucible should be installed

Vitrification of HLW Produced by Uranium/Molybdenum Fuel Reprocessing in COGEMA's Cold Crucible Melter

International Nuclear Information System (INIS)

Do Quang, R.; Petitjean, V.; Hollebecque, F.; Pinet, O.; Flament, T.; Prod'homme, A.

2003-01-01

The performance of the vitrification process currently used in the La Hague commercial reprocessing plants has been continuously improved during more than ten years of operation. In parallel COGEMA (industrial Operator), the French Atomic Energy Commission (CEA) and SGN (respectively COGEMA's R and D provider and Engineering) have developed the cold crucible melter vitrification technology to obtain greater operating flexibility, increased plant availability and further reduction of secondary waste generated during operations. The cold crucible is a compact water-cooled melter in which the radioactive waste and the glass additives are melted by direct high frequency induction. The cooling of the melter produces a solidified glass layer that protects the melter's inner wall from corrosion. Because the heat is transferred directly to the melt, high operating temperatures can be achieved with no impact on the melter itself. COGEMA plans to implement the cold crucible technology to vitrify high level liquid waste from reprocessed spent U-Mo-Sn-Al fuel (used in gas cooled reactor). The cold crucible was selected for the vitrification of this particularly hard-to-process waste stream because it could not be reasonably processed in the standard hot induction melters currently used at the La Hague vitrification facilities : the waste has a high molybdenum content which makes it very corrosive and also requires a special high temperature glass formulation to obtain sufficiently high waste loading factors (12 % in molybdenum). A special glass formulation has been developed by the CEA and has been qualified through lab and pilot testing to meet standard waste acceptance criteria for final disposal of the U-Mo waste. The process and the associated technologies have been also being qualified on a full-scale prototype at the CEA pilot facility in Marcoule. Engineering study has been integrated in parallel in order to take into account that the Cold Crucible should be installed

Characterization of a High-Level Waste Cold Cap in a Laboratory-Scale Melter

Energy Technology Data Exchange (ETDEWEB)

Dixona, Derek R; Schweiger, Michael J; Hrma, Pavel [Pacific Northwest National Laboratory, Richland (United States)

2013-05-15

The feed, slurry or calcine, is charged to the melter from above. The conversion of the melter feed to molten glass occurs within the cold cap, a several centimeters thin layer of the reacting material blanketing the surface of the melt. Between the cold-cap top, which is covered by boiling slurry, and its bottom, where bubbles separate it from molten glass, the temperature changes by ∼900 .deg. C. The heat is delivered to the cold cap from the melt that is stirred mainly by bubbling. The feed contains oxides, hydroxides, acids, inorganic salts and organic materials. On heating, these components react, releasing copious amounts of gases, while molten salts decompose, glass-forming melt is generated, and crystalline phases precipitate and dissolve in the melt. Most of these processes have been studied in detail and became sufficiently understood for a mathematical model to represent the heat and mass transfer within the cold cap. This allows US to relate the rate of melting to the feed properties. While the melting reactions can be studied, and feed properties, such as heat conductivity and density, measured in the laboratory, the actual cold-cap dynamics, as it evolves in the waste glass melter, is not accessible to direct investigation. Therefore, to bridge the gap between the laboratory crucible and the waste glass melter, we explored the cold cap formation in a laboratory-scale melter (LSM) and studied the structure of quenched cold caps. The LSM is a suitable tool for investigating the cold cap. The cold cap that formed in the LSM experiments exhibited macroscopic features observed in scaled melters, as well as microscopic features accessible through laboratory studies and mathematical modeling. The cold cap consists of two main layers. The top layer contains solid particles dissolving in the glass-forming melt and open shafts through which gases are escaping. The bottom layer contains bubbly melt or foam where bubbles coalesce into larger cavities that move

DWPF Glass Melter Technology Manual: Volume 3

Energy Technology Data Exchange (ETDEWEB)

Iverson, D.C.

1993-12-31

This document details information about the design of a glass melter to be used at the Defense Waste Processing Facility located at the Savannah River Site. Topics discussed include: Information collected during testing, equipment, materials, design basis, feed tubes, and an evaluation of the performance of various components. Information is conveyed using many diagrams and photographs.

DWPF Glass Melter Technology Manual: Volume 3

International Nuclear Information System (INIS)

Iverson, D.C.

1993-01-01

This document details information about the design of a glass melter to be used at the Defense Waste Processing Facility located at the Savannah River Site. Topics discussed include: Information collected during testing, equipment, materials, design basis, feed tubes, and an evaluation of the performance of various components. Information is conveyed using many diagrams and photographs

The Behavior and Effects of the Noble Metals in the DWPF Melter System

International Nuclear Information System (INIS)

Smith, M.E.; Bickford, D.F.

1997-01-01

Governments worldwide have committed to stabilization of high-level nuclear waste (HLW) by vitrification to a durable glass form for permanent disposal. All of these nuclear wastes contain the fission-product noble metals: ruthenium, rhodium, and palladium. SRS wastes also contain natural silver from iodine scrubbers. Closely associated with the noble metals are the fission products selenium and tellurium which are chemical analogs of sulfur and which combine with noble metals to influence their behavior and properties. Experience has shown that these melt insoluble metals and their compounds tend to settle to the floor of Joule-heated ceramic melters. In fact, almost all of the major research and production facilities have experienced some operational problem which can be associated with the presence of dense accumulations of these relatively conductive metals and/or their compounds. In most cases, these deposits have led to a loss of production capability, in some cases, to the point that melter operation could not continue. HLW nuclear waste vitrification facilities in the United States are the Department of Energy's Defense Waste Processing Facility (DWPF) at the Savannah River Site, the planned Hanford Waste Vitrification Plant (HWVP) at the Hanford Site and the operating West Valley Demonstration Project (WVDP) at West Valley, NY. The Integrated DWPF Melter System (IDMS) is a vitrification test facility at the Savannah River Technology Center (SRTC). It was designed and constructed to provide an engineering-scale representation of the DWPF melter and its associated feed preparation and off-gas treatment systems. An extensive noble metals testing program was begun in 1990. The objectives of this task were to explore the effects of the noble metals on the DWPF melter feed preparation and waste vitrification processes. This report focuses on the vitrification portion of the test program

Energy expenditure in caving.

Directory of Open Access Journals (Sweden)

Giorgia Antoni

Full Text Available The aim of this study was to determine the energy expenditure of a group of cavers of both genders and different ages and experience during a 10 hour subterranean exploration, using portable metabolimeters. The impact of caving activity on body composition and hydration were also assessed through bioelectrical impedance, and nutritional habits of cavers surveyed. During cave activity, measured total energy expenditure (TEE was in the range 225-287 kcal/h for women-men (MET = 4.1, respectively; subjects had an energy intake from food in the range 1000-1200 kcal, thus inadequate to restore lost calories. Bayesian statistical analysis estimated the effect of predictive variables on TEE, revealing that experienced subjects had a 5% lower TEE than the less skilled ones and that women required a comparatively larger energy expenditure than men to perform the same task. BIVA (bioelectrical impedance vector analysis showed that subjects were within the range of normal hydration before and after cave activity, but bioelectrical changes indicated a reduction of extracellular water in men, which might result in hypo-osmolal dehydration in the case of prolonged underground exercise. All these facts should be considered when planning cave explorations, preparing training programs for subjects practising caving, and optimizing a diet for cavers. Further, information gathered through this study could be of value to reduce accidents in caves related to increase in fatigue.

Investigation of clay sediments and bedrock morphology in caves with seismic traveltime tomography: an application at Alepotrypa Cave (Diros, Greece

Directory of Open Access Journals (Sweden)

Lazaros Polymenakos

2017-01-01

Full Text Available The deposition of unconsolidated clay sediments in caves, in relation to the buried morphology of the karstic conduit, are important parameters for the study of cave evolution. We introduce the application of an active seismic imaging technique to investigate the clay deposits and bedrock morphology in caves. Seismic traveltime tomography, applied for the first time in cave studies, can assist with the interpretation of cave geomorphology. Utilizing the P-wave velocity contrast between the clay sediments and the surrounding rock mass, we map the buried rock surface and significant sediment interfaces and provide an estimate of the sediment thickness and volume. Our study focuses on the Alepotrypa Cave located in Diros (Peloponnese, Greece, revealing important information for the evolution of the cave. The proposed technique could be applied in caves with significant clay deposits, in order to constrain the clay volume and reconstruct the buried floor shape of the cave. The technique exploits fully the ground morphology and access points in a cave, so it is suitable for a detailed three-dimensional exploration of cave deposits and the underlying cave morphology.

GEOMORPHIC ANALYSIS OF MAWSMAI CAVE, MEGHALAYA, INDIA

Directory of Open Access Journals (Sweden)

Vibhash Chandra Jha

2011-12-01

Full Text Available ABSTRACT Caving is an art which can be best experienced in the mystic Mawsmai Cave of Meghalaya. This Cave is fast becoming a hot tourist’s destination offering great adventurous opportunity to the tourists. The cave is located in the East Khasi Hill region near Cherrapunjee and is made of limestone. The emotion of thrill heightens after entering the cave. The entrance has a narrow vertical opening and is well lit. Due to its location in the world’s largest rainfall region, dripping of water from the cave roofs occurs almost throughout the year. The formation of stalactites and stalagmites create wonderful phenomena specially found in this caves. The conspicuous pillars formed due to the joining of the roof and the floors are an awe-inspiring creativity of the creator of this world. Keywords: Cave, Limestone, Stalactite, Stalagmite, Pillar, Solution.

Food sources of selected terrestrial cave arthropods

Czech Academy of Sciences Publication Activity Database

Smrž, J.; Kováč, L.; Mikeš, J.; Šustr, Vladimír; Lukešová, Alena; Tajovský, Karel; Nováková, Alena; Režňáková, P.

2015-01-01

Roč. 16, č. 1 (2015), s. 37-46 ISSN 1768-1448 Grant - others:Vega(SK) 1/0139/09 Institutional research plan: CEZ:AV0Z60660521 Institutional support: RVO:60077344 Keywords : Acari * caves * Collembola * Diplopoda * feeding habits * Isopoda Subject RIV: EG - Zoology

Control of DWPF [Defense Waste Processing Facility] melter feed composition

International Nuclear Information System (INIS)

Edwards, R.E. Jr.; Brown, K.G.; Postles, R.L.

1990-01-01

The Defense Waste Processing Facility will be used to immobilize Savannah River Site high-level waste into a stable borosilicate glass for disposal in a geologic repository. Proper control of the melter feed composition in this facility is essential to the production of glass which meets product durability constraints dictated by repository regulations and facility processing constraints dictated by melter design. A technique has been developed which utilizes glass property models to determine acceptable processing regions based on the multiple constraints imposed on the glass product and to display these regions graphically. This system along with the batch simulation of the process is being used to form the basis for the statistical process control system for the facility. 13 refs., 3 figs., 1 tab

LFCM [liquid-fed ceramic melter] vitrification technology: Quarterly progress report, January--March 1987

International Nuclear Information System (INIS)

Brouns, R. A.; Allen, C. R.; Powell, J. A.

1988-05-01

This report is compiled by the Nuclear Waste Treatment Program and the Hanford Waste Vitrification Program at Pacific Northwest Laboratory to describe the progress in developing, testing, applying and documenting liquid-fed ceramic melter vitrification technology. Progress in the following technical subject areas during the second quarter of FY 1987 is discussed: melting process chemistry and glass development, feed preparation and transfer systems, melter systems, canister filling and handling systems, and process/product modeling. 23 refs., 14 figs., 10 tabs

Cave Tourism: The Potential of Asar Cave as a Natural Tourism Asset at Lenggong Valley, Perak

Directory of Open Access Journals (Sweden)

Rindam Main

2014-01-01

Full Text Available The Lenggong Valley, from a standpoint of natural tourism research, presents strengths, weaknesses, opportunities and challenges that can be utilized to help increase the opportunities for the local community to increase their standard of living. Asar Cave comprises one of the caves that are found in Lenggong. A series of external studies have been done on Asar Cave in order to measure its potential for natural tourism in Lenggong. The objective of this study is to discuss caves as a natural resource that has great potential in the growth of the economy of the residents of the Lenggong Valley. Marketing caves as a source of nature tourism helps the government’s achievements in National Key Result Areas, apart from being a form of environmental control as well as helping to increase awareness about environmental education, specifically those associated with caves. The research results find that SWOT analysis presents huge potential for caves to become a source of nature tourism development in Lenggong. Great potential can also be seen from a standpoint of increasing the standard of living of its residents through their involvement in the tourism sector based on local natural assets.

Integrated DWPF Melter System (IDMS) campaign report: The first two noble metals operations

International Nuclear Information System (INIS)

Hutson, N.D.; Zamecnik, J.R.; Smith, M.E.; Miller, D.H.; Ritter, J.A.

1991-01-01

The Integrated DWPF Melter System (IDMS) is designed and constructed to provide an engineering-scale representation of the DWPF melter and its associated feed preparation and off-gas systems. The facility is the first pilot-scale melter system capable of processing mercury, and flowsheet levels of halides and noble metals. In order to characterize the processing of noble metals (Pd, Rh, Ru, and Ag) on a large scale, the IDMS will be operated batchstyle for at least nine feed preparation cycles. The first two of these operations are complete. The major observation to date occurred during the second run when significant amounts of hydrogen were evolved during the feed preparation cycle. The runs were conducted between June 7, 1990 and March 8, 1991. This time period included nearly six months of ''fix-up'' time when forced air purges were installed on the SRAT MFT and other feed preparation vessels to allow continued noble metals experimentation

Preliminary analysis of species partitioning in the DWPF melter. Sludge batch 7A

Energy Technology Data Exchange (ETDEWEB)

Choi, A. S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Smith III, F. G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); McCabe, D. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-01-01

The work described in this report is preliminary in nature since its goal was to demonstrate the feasibility of estimating the off-gas carryover from the Defense Waste Processing Facility (DWPF) melter based on a simple mass balance using measured feed and glass pour stream (PS) compositions and time-averaged melter operating data over the duration of one canister-filling cycle. The DWPF has been in radioactive operation for over 20 years processing a wide range of high-level waste (HLW) feed compositions under varying conditions such as bubbled vs. non-bubbled and feeding vs. idling. So it is desirable to find out how the varying feed compositions and operating parameters would have impacted the off-gas entrainment. However, the DWPF melter is not equipped with off-gas sampling or monitoring capabilities, so it is not feasible to measure off-gas entrainment rates directly. The proposed method provides an indirect way of doing so.

Volatilization and redox testing in a DC arc melter: FY-93 and FY-94

International Nuclear Information System (INIS)

Grandy, J.D.; Sears, J.W.; Soelberg, N.R.; Reimann, G.A.; McIlwain, M.E.

1996-07-01

The purpose of these experiments was to study the dissolution, retention, volatilization, and trapping of transuranic radionuclide elements (TRUs), mixed fission and activation products, and high vapor pressure metals (HVPMS) during processing in a high temperature arc furnace. In all cases, surrogate elements (lanthanides) were used in place of radioactive ones. The experiments were conducted utilizing a small DC arc melter developed at the Idaho National Engineering Laboratory (INEL) Research Center (IRC). The small arc melter was originally developed in 1992 and has been used previously for waste form studies of iron enriched basalt (IEB) and IEB with zirconium and titanium additions (IEB4). Section 3 contains a description of the small arc melter and its operational capabilities are discussed in Chapter 4. The remainder of the document describes each testing program and then discusses results and findings

The Mammoth Cave system, Kentucky, USA; El sistema de la Mammoth Cave, Kentucky, EE.UU

Energy Technology Data Exchange (ETDEWEB)

Palmer, A. N.

2016-07-01

Mammoth Cave is the main attraction of Mammoth Cave National Park. For several decades it has been the longest known cave in the world and currently contains 652 km in 2016 of surveyed passages. It is located in the heart of an extensive karst plateau, in which the stratal dip averages only one degree. The cave is part of a drainage basin of more than 200 km{sup 2}. The cave has been known to local inhabitants for several millennia and contains a rich trove of archaeological and historical artifacts. It contains many speleo biota including several rare and endangered species and has been designated a World Heritage Site and an International Biosphere Reserve (UNESCO). Its many passage levels and sediments contain a record of the fluvial history of most of south-eastern North America. (Author)

Instrumenting caves to collect hydrologic and geochemical data: case study from James Cave, Virginia

Science.gov (United States)

Schreiber, Madeline E.; Schwartz, Benjamin F.; Orndorff, William; Doctor, Daniel H.; Eagle, Sarah D.; Gerst, Jonathan D.

2015-01-01

Karst aquifers are productive groundwater systems, supplying approximately 25 % of the world’s drinking water. Sustainable use of this critical water supply requires information about rates of recharge to karst aquifers. The overall goal of this project is to collect long-term, high-resolution hydrologic and geochemical datasets at James Cave, Virginia, to evaluate the quantity and quality of recharge to the karst system. To achieve this goal, the cave has been instrumented for continuous (10-min interval) measurement of the (1) temperature and rate of precipitation; (2) temperature, specific conductance, and rate of epikarst dripwater; (3) temperature of the cave air; and (4) temperature, conductivity, and discharge of the cave stream. Instrumentation has also been installed to collect both composite and grab samples of precipitation, soil water, the cave stream, and dripwater for geochemical analysis. This chapter provides detailed information about the instrumentation, data processing, and data management; shows examples of collected datasets; and discusses recommendations for other researchers interested in hydrologic and geochemical monitoring of cave systems. Results from the research, briefly described here and discussed in more detail in other publications, document a strong seasonality of the start of the recharge season, the extent of the recharge season, and the geochemistry of recharge.

Petrographic and geochemical study on cave pearls from Kanaan Cave (Lebanon

Directory of Open Access Journals (Sweden)

Nader Fadi H.

2007-01-01

Full Text Available The Kanaan cave is situated at the coastal zone, north of Beirut City (capital of Lebanon. The cave is located within the upper part of the Jurassic Kesrouane Formation (Liassic to Oxfordian which consists mainly of micritic limestone. Twenty seven cave pearls were subjected to petrographic (conventional and scanning electron microscopy and geochemical analyses (major/trace elements and stable isotopes. The cave pearls were found in an agitated splash-pool with low mud content. They are believed to have formed through chemical precipitation of calcite in water over-saturated with calcium. The nucleus and micritic laminae show δ18OV-PDB values of about -5.0‰ and δ13C V-PDB values of -11.8‰, while the surrounding calcite spar laminae resulted in δ18OV-PDB ranging between -5.3 and -5.2‰, and δ13C V-PDB between -12.3 and -12.1‰. A genesis/diagenesis model for these speleothems is proposed involving recrystallization which has selectively affected the inner layers of the cave pearls. This is chiefly invoked by sparry calcite crystals ‘invading’ the inner micrite cortical laminae and the nuclei (cross-cutting the pre-existing mud-envelopes, and the slight depletion in δ18O values from inner to outer cortical layers. The calculated δ18OV-SMOW of the water (-4.2‰ matches with data on meteoric water signature for the central eastern Mediterranean region.

Proposed Strategies for DWPF Melter Off-Gas Surge Control

International Nuclear Information System (INIS)

CHOI, ALEXANDERS.

2004-01-01

Off-gas surging is inherent to the operation of slurry-fed melters. Although the melter design and the feed chemistry are both known to significantly affect off-gas surging, the frequency and intensity of surges are in essence unpredictable. In typical off-gas surges, both condensable and non condensable flows spike simultaneously. Condensable or steam surges have been observed to occur as the boiling water layer occasionally falls into the crevices of the cold cap or flows over the edges of the cold cap, thereby coming in contact with the melt surface. The resulting steam surges can pressurize the melter considerably and, therefore, are responsible for the bulk of pressure transients that propagate throughout the off-gas system. The non condensable surges occur as the calcine gases that have been accumulating within the cold cap finally build up enough pressure to be released through the temporary openings of the cold cap. The analysis of off-gas data has shown that over 90 of the gas released during a surge is due to steam.1 Therefore, it is essential to have a large inventory of water in the cold cap for any significant pressure spikes to occur. With the Melter 2 vapor space temperature typically running at 720C, the water layer in the cold cap will quickly evaporate once the feeding stops, and the potential for any large pressure spikes should practically cease to exist. The analysis also showed that large pressure spikes well above 2 inches H2O cannot occur under the steam surge scenarios described above. More severe conditions should prevail and one such condition would be that the feed materials form a mound with a growing lake on top, while the melt below remains very fluidic due to its low viscosity, thus resulting in greater movements both in the lateral as well as vertical directions. Once the mound begins to grow, its rate should accelerate, since the heat transfer rate to the upper regions of the cold cap is inversely proportional to the cold cap

Startup and operation of a plant-scale continuous glass melter for vitrification of Savannah River Plant simulated waste

International Nuclear Information System (INIS)

Willis, T.A.

1980-01-01

The reference process for disposal of radioactive waste from the Savannah River Plant is vitrification of the waste in borosilicate glass in a continuous glass melter. Design, startup, and operation of a plant-scale developmental melter system are discussed

Environmental conditions of Borra Cave, Visakhapattanam, India

Directory of Open Access Journals (Sweden)

Haraprasad Bairagya

2014-05-01

Full Text Available Caving is an art which can be best experienced in the mystic Borra of Eastern Ghats and ranked as the second largest cave of India just after Belum Caves situated in the same state Andhrapradesh, India. This Cave is fast becoming a hot tourist?s destination offering great adventurous opportunity to the tourists in the Eastern Ghats. The cave is located in the Ananthagiri hills of the Eastern Ghats region near Visakhapattanam and is made of limestone. The emotion of thrill heightens after entering the cave. The entrance has a narrow vertical opening and is well lit. Due to its location in the sub-equatorial region, dripping of water from the cave roofs occurs almost throughout the year. The formation of stalactites and stalagmites create wonderful phenomena specially found in this cave. The conspicuous pillars formed due to the joining of the roof and the floors are an awe-inspiring creativity of the creator of this world. Various viruses and bacteria are in the cave interior along with different other creatures. The Borra cave helps the Govt. of Andhra Pradesh, India, to earn huge economic benefits for the sake of tourism industry. DOI: http://dx.doi.org/10.3126/ije.v3i2.10526 International Journal of the Environment Vol.3(2 2014: 150-166

Unexpected diversity of sandflies (Diptera: Psychodidae) in tourist caves in Northern Thailand.

Science.gov (United States)

Sukantamala, Jedsada; Sing, Kong-Wah; Jaturas, Narong; Polseela, Raxsina; Wilson, John-James

2017-11-01

Certain species of Phlebotomine sandflies (Diptera: Psychodidae) are vectors of the protozoa which causes leishmaniasis. Sandflies are found breeding in enclosed places like caves. Thailand is a popular tourist destination, including for ecotourism activities like caving, which increases the risk of contact between tourists and sandflies. Surveillance of sandflies is important for monitoring this risk but identification of species based on morphology is challenged by phenotypic plasticity and cryptic diversity. DNA barcodes have been used for the identification of sandflies in Thailand. We collected sandflies using CDC light trap from four tourist caves in Northern Thailand. Female sandflies were provisionally sorted into 13 morphospecies and 19 unidentified specimens. DNA was extracted from the thorax and legs of sandflies and the DNA barcode region of cytochrome c oxidase I mtDNA amplified and sequenced. The specimens were sorted into 22 molecular operational taxonomic units (MOTU) based on the 145 DNA barcodes, which is significantly more than the morphospecies. Several of the taxa thought to be present in multiple caves, based on morphospecies sorting, split into cave-specific MOTU which likely represent cryptic species. Several MOTU reported in an earlier study from Wihan Cave, Thailand, were also found in these caves. This supports the use of DNA barcodes to investigate species diversity of sandflies and their useful role in surveillance of sandflies in Thailand.

Improved mixing and sampling systems for vitrification melter feeds

International Nuclear Information System (INIS)

Ebadian, M.A.

1998-01-01

This report summarizes the methods used and results obtained during the progress of the study of waste slurry mixing and sampling systems during fiscal year 1977 (FY97) at the Hemispheric Center for Environmental Technology (HCET) at Florida International University (FIU). The objective of this work is to determine optimal mixing configurations and operating conditions as well as improved sampling technology for defense waste processing facility (DWPF) waste melter feeds at US Department of Energy (DOE) sites. Most of the research on this project was performed experimentally by using a tank mixing configuration with different rotating impellers. The slurry simulants for the experiments were prepared in-house based on the properties of the DOE sites' typical waste slurries. A sampling system was designed to withdraw slurry from the mixing tank. To obtain insight into the waste mixing process, the slurry flow in the mixing tank was also simulated numerically by applying computational fluid dynamics (CFD) methods. The major parameters investigated in both the experimental and numerical studies included power consumption of mixer, mixing time to reach slurry uniformity, slurry type, solids concentration, impeller type, impeller size, impeller rotating speed, sampling tube size, and sampling velocities. Application of the results to the DWPF melter feed preparation process will enhance and modify the technical base for designing slurry transportation equipment and pipeline systems. These results will also serve as an important reference for improving waste slurry mixing performance and melter operating conditions. These factors will contribute to an increase in the capability of the vitrification process and the quality of the waste glass

ENHANCED DOE HIGH LEVEL WASTE MELTER THROUGHPUT STUDIES: SRNL GLASS SELECTION STRATEGY

Energy Technology Data Exchange (ETDEWEB)

Raszewski, F; Tommy Edwards, T; David Peeler, D

2008-01-23

The Department of Energy has authorized a team of glass formulation and processing experts at the Savannah River National Laboratory (SRNL), the Pacific Northwest National Laboratory (PNNL), and the Vitreous State Laboratory (VSL) at Catholic University of America to develop a systematic approach to increase high level waste melter throughput (by increasing waste loading with minimal or positive impacts on melt rate). This task is aimed at proof-of-principle testing and the development of tools to improve waste loading and melt rate, which will lead to higher waste throughput. Four specific tasks have been proposed to meet these objectives (for details, see WSRC-STI-2007-00483): (1) Integration and Oversight, (2) Crystal Accumulation Modeling (led by PNNL)/Higher Waste Loading Glasses (led by SRNL), (3) Melt Rate Evaluation and Modeling, and (4) Melter Scale Demonstrations. Task 2, Crystal Accumulation Modeling/Higher Waste Loading Glasses is the focus of this report. The objective of this study is to provide supplemental data to support the possible use of alternative melter technologies and/or implementation of alternative process control models or strategies to target higher waste loadings (WLs) for the Defense Waste Processing Facility (DWPF)--ultimately leading to higher waste throughputs and a reduced mission life. The glass selection strategy discussed in this report was developed to gain insight into specific technical issues that could limit or compromise the ability of glass formulation efforts to target higher WLs for future sludge batches at the Savannah River Site (SRS). These technical issues include Al-dissolution, higher TiO{sub 2} limits and homogeneity issues for coupled-operations, Al{sub 2}O{sub 3} solubility, and nepheline formation. To address these technical issues, a test matrix of 28 glass compositions has been developed based on 5 different sludge projections for future processing. The glasses will be fabricated and characterized based on

Cave monitoring in the Béke and Baradla caves (Northeastern Hungary: implications for the conditions for the formation cave carbonates

Directory of Open Access Journals (Sweden)

György Czuppon

2018-01-01

Full Text Available In order to use speleothems in the reconstruction of past climate and environmental changes it is necessary to understand the environmental and hydrological processes that determine the physico-chemical conditions of carbonate precipitation and hence speleothem formation. Therefore, in this study an extended monitoring program was conducted in the Béke and Baradla caves located in the Aggtelek region (Northeastern Hungary. The studied caves are rich in speleothem and flowstone occurrences with great potential for paleoclimatology studies. The monitoring activity included measurements of atmospheric and cave temperatures, CO2 concentration in cave air, as well as chemical and isotopic compositions of water samples (drip water, precipitation and in situ carbonate precipitates. The hydrogen and oxygen isotope compositions of drip waters showed no seasonal variation at any of the collection sites, indicating a well-mixed karstic aquifer. This implies that the isotopic compositions of local speleothems were able to record multiannual isotopic changes inherited from stable isotopes in the drip water. CO2 concentration showed seasonality (high values in summer and low values in winter in both caves, likely affecting carbonate precipitation or corrosion and consequently stalagmite growth. Systematic variations among Mg/Ca and Sr/Ca, Na/Ca, and Si/Ca element ratios were detected in the drip water suggesting Prior Calcite Precipitation (PCP. As PCP is characteristic of periods of reduced infiltration during drier weather conditions, the variations in drip water chemistry and drip rates indicate that the hydrological conditions also varied significantly during the studied period. This hydrological variability appears to affect not only trace element composition but also the isotopic composition of modern carbonate precipitates. In summary, these findings imply that the speleothems from the studied caves were able to record the hydrological changes

Spotted hyena and steppe lion predation behaviours on cave bears of Europe - ?Late Quaternary cave bear extinction as result of predator stress

Science.gov (United States)

Diedrich, Cajus G.

2010-05-01

Cave bears hibernated in caves all over Eurasia (e.g. Rabeder et al., 2000) including alpine regions using mainly larger caves for this purpose. Late Quaternary spotted hyenas Crocuta crocuta spelaea instead occupied mainly areas close to the cave entrances as their dens (Diedrich and Žák 2006, Diedrich 2010). The largest predator, the steppe lion Panthera leo spelaea was only a sporadic cave dweller (Diedrich 2007b, 2009b). His presence and its remains from caves all over Europe can be recently explained best as result of imported carcasses after killing by their largest antagonists, the Late Quaternary spotted hyenas. In some cases the kill might have happened in the hyena den cave itself during the theft of prey remains by lions (Diedrich 2009a). Another reason of their remains in caves of Europe is the hunting onto the herbivorous cave bears, especially during hibernation times, when megafauna prey was less available in the open environments (Diedrich 2009c). These lion remains from caves of Europe, nearly all of which were from adult animals, provide evidence of active predation by lions onto cave bears even in medium high alpine regions (Diedrich 2009b, in review). Lion skeletons in European cave bear dens were therefore often found amongst originally articulated cave bear skeletons or scattered cave bear remains and even close to their hibernation nests (Diedrich et al. 2009c, in review). Not only lions fed on cave bears documented mainly by the large quantities of chewed, punctured and crushed cave bear long-bones; even damaged skulls reveal that hyenas scavenged primarily on cave bear carcasses which were mainly responsible for the destruction of their carcasses and bones (Diedrich 2005, 2009d). Predation and scavenging on cave bears by the two largest Late Quaternary predators C. c. spelaea and P. l. spelaea explains well the large quantity of fragmented cave bear bones over all European caves in low to medium high mountainous elevations, whereas in

Evolution of cave Axiokebuita and Speleobregma (Scalibregmatidae, Annelida)

DEFF Research Database (Denmark)

Martinez Garcia, Alejandro; Di Domenico, Maikon; Worsaae, Katrine

2013-01-01

The evolutionary history of Axiokebuita and Speleobregma, two poorly known lineages of annelids exclusive from deep-sea or marine caves but always from crevicular habitats, is explored here. Speleobregma lanzaroteum Bertelsen, 1986, and Axiokebuita cavernicola sp. n. are described from anchialine...... ciliated palps. Our results support two independent cave colonization events, favoured by the preadaptation of the members of Axiokebuita-Speleobregma lineage to crevicular habitats.......The evolutionary history of Axiokebuita and Speleobregma, two poorly known lineages of annelids exclusive from deep-sea or marine caves but always from crevicular habitats, is explored here. Speleobregma lanzaroteum Bertelsen, 1986, and Axiokebuita cavernicola sp. n. are described from anchialine...

Bacterial community survey of sediments at Naracoorte Caves, Australia

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Ball Andrew S.

2012-07-01

Full Text Available Bacterial diversity in sediments at UNESCO World Heritage listed Naracoorte Caves was surveyed as part of an investigation carried out in a larger study on assessing microbial communities in caves. Cave selection was based on tourist accessibility; Stick Tomato and Alexandra Cave (> 15000 annual visits and Strawhaven Cave was used as control (no tourist access. Microbial analysis showed that Bacillus was the most commonly detected microbial genus by culture dependent and independent survey of tourist accessible and inaccessible areas of show (tourist accessible and control caves. Other detected sediment bacterial groups were assigned to the Firmicutes, Actinobacteria and Proteobacteria. The survey also showed differences in bacterial diversity in caves with human access compared to the control cave with the control cave having unique microbial sequences (Acinetobacter, Agromyces, Micrococcus and Streptomyces. The show caves had higher bacterial counts, different 16S rDNA based DGGE cluster patterns and principal component groupings compared to Strawhaven. Different factors such as human access, cave use and configurations could have been responsible for the differences observed in the bacterial community cluster patterns (tourist accessible and inaccessible areas of these caves. Cave sediments can therefore act as reservoirs of microorganisms. This might have some implications on cave conservation activities especially if these sediments harbor rock art degrading microorganisms in caves with rock art.

Is radon emission in caves causing deletions in satellite DNA sequences of cave-dwelling crickets?

Directory of Open Access Journals (Sweden)

Giuliana Allegrucci

Full Text Available The most stable isotope of radon, 222Rn, represents the major source of natural radioactivity in confined environments such as mines, caves and houses. In this study, we explored the possible radon-related effects on the genome of Dolichopoda cave crickets (Orthoptera, Rhaphidophoridae sampled in caves with different concentrations of radon. We analyzed specimens from ten populations belonging to two genetically closely related species, D. geniculata and D. laetitiae, and explored the possible association between the radioactivity dose and the level of genetic polymorphism in a specific family of satellite DNA (pDo500 satDNA. Radon concentration in the analyzed caves ranged from 221 to 26,000 Bq/m3. Specimens coming from caves with the highest radon concentration showed also the highest variability estimates in both species, and the increased sequence heterogeneity at pDo500 satDNA level can be explained as an effect of the mutation pressure induced by radon in cave. We discovered a specific category of nuclear DNA, the highly repetitive satellite DNA, where the effects of the exposure at high levels of radon-related ionizing radiation are detectable, suggesting that the satDNA sequences might be a valuable tool to disclose harmful effects also in other organisms exposed to high levels of radon concentration.

New updated results of paleomagnetic dating of cave deposits exposed in Za Hájovnou Cave, Javoříčko Karst

Czech Academy of Sciences Publication Activity Database

Kadlec, Jaroslav; Čížková, Kristýna; Šlechta, Stanislav

2014-01-01

Roč. 70, 1-2 (2014), s. 27-34 ISSN 0036-5343 Institutional support: RVO:67985530 ; RVO:67985831 Keywords : Javoříčko Karst * Za Hájovnou Cave * Early and Middle Pleistocene * paleomagnetic dating Subject RIV: DB - Geology ; Mineralogy

Occupational exposure to radon in Australian Tourist Caves an Australian-wide study of radon levels

International Nuclear Information System (INIS)

Solomon, S.B.; Langroo, R.; Peggie, J.R.; Lyons, R.G.; James, J.M.

1996-02-01

The study described in this report sets out to determine which Australian show caves have long- term radon levels in excess of the proposed action level of 1000 Bq m -3 . The collaborative study between the Australian Radiation Laboratory (ARL), the University of Sydney and the University of Auckland, was carried out with the support of a Research Grant from Worksafe Australia. The aims of this study were to measure radon levels for each season over a period of one year, at representative sites in all developed show caves around Australia, to determine yearly average radon levels for each cave tour, based on these site measurements, to estimate the radiation doses to the tour guides employed in these caves, and to identify caves with radon concentrations in excess of the action level. (authors)

Crystal-Tolerant Glass Approach For Mitigation Of Crystal Accumulation In Continuous Melters Processing Radioactive Waste

International Nuclear Information System (INIS)

Kruger, Albert A.; Rodriguez, Carmen P.; Lang, Jesse B.; Huckleberry, Adam R.; Matyas, Josef; Owen, Antoinette T.

2012-01-01

High-level radioactive waste melters are projected to operate in an inefficient manner as they are subjected to artificial constraints, such as minimum liquidus temperature (T L ) or maximum equilibrium fraction of crystallinity at a given temperature. These constraints substantially limit waste loading, but were imposed to prevent clogging of the melter with spinel crystals [(Fe, Ni, Mn, Zn)(Fe, Cr) 2 O 4 ]. In the melter, the glass discharge riser is the most likely location for crystal accumulation during idling because of low glass temperatures, stagnant melts, and small diameter. To address this problem, a series of lab-scale crucible tests were performed with specially formulated glasses to simulate accumulation of spinel in the riser. Thicknesses of accumulated layers were incorporated into empirical model of spinel settling. In addition, T L of glasses was measured and impact of particle agglomeration on accumulation rate was evaluated. Empirical model predicted well the accumulation of single crystals and/or smallscale agglomerates, but, excessive agglomeration observed in high-Ni-Fe glass resulted in an under-prediction of accumulated layers, which gradually worsen over time as an increased number of agglomerates formed. Accumulation rate of ∼14.9 +- 1 nm/s determined for this glass will result in ∼26 mm thick layer in 20 days of melter idling

Durability of glasses from the Hg-doped Integrated DWPF Melter System (IDMS) campaign

International Nuclear Information System (INIS)

Jantzen, C.M.

1992-01-01

The Integrated DWPF Melter System (IDMS) for the vitrification of high-level radioactive wastes is designed and constructed to be a 1/9th scale prototype of the full scale Defense Waste Processing Facility (DWPF) melter. The IDMS facility is the first engineering scale melter system capable of processing mercury, and flowsheet levels of halides and noble metals. In order to determine the effects of mercury on the feed preparation process, the off-gas chemistry, glass melting behavior, and glass durability, a three-run mercury (Hg) campaign was conducted. The glasses produced during the Hg campaign were composed of Batch 1 sludge, simulated precipitate hydrolysis aqueous product (PHA) from the Precipitate Hydrolysis Experimental Facility (PHEF), and Frit 202. The glasses were produced using the DWPF process/product models for glass durability, viscosity, and liquidus. The durability model indicated that the glasses would all be more durable than the glass qualified in the DWPF Environmental Assessment (EA). The glass quality was verified by performing the Product Consistency Test (PCT) which was designed for glass durability testing in the DWPF

Characterization of Ceramic Material Produced From a Cold Crucible Induction Melter Test

Energy Technology Data Exchange (ETDEWEB)

Amoroso, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Marra, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-04-30

This report summarizes the results from characterization of samples from a melt processed surrogate ceramic waste form. Completed in October of 2014, the first scaled proof of principle cold crucible induction melter (CCIM) test was conducted to process a Fe-hollandite-rich titanate ceramic for treatment of high level nuclear waste. X-ray diffraction, electron microscopy, inductively coupled plasma-atomic emission spectroscopy (and inductively coupled plasma-mass spectroscopy for Cs), and product consistency tests were used to characterize the CCIM material produced. Core samples at various radial locations from the center of the CCIM were taken. These samples were also sectioned and analyzed vertically. Together, the various samples were intended to provide an indication of the homogeneity throughout the CCIM with respect to phase assemblage, chemical composition, and chemical durability. Characterization analyses confirmed that a crystalline ceramic with desirable phase assemblage was produced from a melt using a CCIM. Hollandite and zirconolite were identified in addition to possible highly-substituted pyrochlore and perovskite. Minor phases rich in Fe, Al, or Cs were also identified. Remarkably only minor differences were observed vertically or radially in the CCIM material with respect to chemical composition, phase assemblage, and durability. This recent CCIM test and the resulting characterization in conjunction with demonstrated compositional improvements support continuation of CCIM testing with an improved feed composition and improved melter system.

Hazards analysis of TNX Large Melter-Off-Gas System

International Nuclear Information System (INIS)

Randall, C.T.

1982-03-01

Analysis of the potential safety hazards and an evaluation of the engineered safety features and administrative controls indicate that the LMOG System can be operated without undue hazard to employees or the public, or damage to equipment. The safety features provided in the facility design coupled with the planned procedural and administrative controls make the occurrence of serious accidents very improbable. A set of recommendations evolved during this analysis that was judged potentially capable of further reducing the probability of personnel injury or further mitigating the consequences of potential accidents. These recommendations concerned areas such as formic acid vapor hazards, hazard of feeding water to the melter at an uncontrolled rate, prevention of uncontrolled glass pours due to melter pressure excursions and additional interlocks. These specific suggestions were reviewed with operational and technical personnel and are being incorporated into the process. The safeguards provided by these recommendations are discussed in this report

Cave breakdown by vadose weathering.

Directory of Open Access Journals (Sweden)

Osborne R. Armstrong L.

2002-01-01

Full Text Available Vadose weathering is a significant mechanism for initiating breakdown in caves. Vadose weathering of ore bodies, mineral veins, palaeokarst deposits, non-carbonate keystones and impure, altered or fractured bedrock, which is intersected by caves, will frequently result in breakdown. Breakdown is an active, ongoing process. Breakdown occurs throughout the vadose zone, and is not restricted to large diameter passages, or to cave ceilings. The surfaces of disarticulated blocks are commonly coated, rather than having fresh broken faces, and blocks continue to disintegrate after separating from the bedrock. Not only gypsum, but also hydromagnesite and aragonite are responsible for crystal wedging. It is impossible to study or identify potential breakdown foci by surface surveys alone, in-cave observation and mapping are essential.

Predictive modeling of crystal accumulation in high-level waste glass melters processing radioactive waste

Science.gov (United States)

Matyáš, Josef; Gervasio, Vivianaluxa; Sannoh, Sulaiman E.; Kruger, Albert A.

2017-11-01

The effectiveness of high-level waste vitrification at Hanford's Waste Treatment and Immobilization Plant may be limited by precipitation/accumulation of spinel crystals [(Fe, Ni, Mn, Zn)(Fe, Cr)2O4] in the glass discharge riser of Joule-heated ceramic melters during idling. These crystals do not affect glass durability; however, if accumulated in thick layers, they can clog the melter and prevent discharge of molten glass into canisters. To address this problem, an empirical model was developed that can predict thicknesses of accumulated layers as a function of glass composition. This model predicts well the accumulation of single crystals and/or small-scale agglomerates, but excessive agglomeration observed in high-Ni-Fe glass resulted in an underprediction of accumulated layers, which gradually worsened over time as an increased number of agglomerates formed. The accumulation rate of ∼53.8 ± 3.7 μm/h determined for this glass will result in a ∼26 mm-thick layer after 20 days of melter idling.

Predictive modeling of crystal accumulation in high-level waste glass melters processing radioactive waste

Energy Technology Data Exchange (ETDEWEB)

Matyáš, Josef; Gervasio, Vivianaluxa; Sannoh, Sulaiman E.; Kruger, Albert A.

2017-11-01

The effectiveness of HLW vitrification is limited by precipitation/accumulation of spinel crystals [(Fe, Ni, Mn, Zn)(Fe, Cr)2O4] in the glass discharge riser of Joule-heated ceramic melters during idling. These crystals do not affect glass durability; however, if accumulated in thick layer, they can clog the melter and prevent discharge of molten glass into canisters. To address this problem, an empirical model was developed that can predict thicknesses of accumulated layers as a function of glass composition. This model predicts well the accumulation of single crystals and/or small-scale agglomerates, but, excessive agglomeration observed in high-Ni-Fe glass resulted in an under-prediction of accumulated layers, which gradually worsen over time as an increased number of agglomerates formed. Accumulation rate of ~53.8 ± 3.7 µm/h determined for this glass will result in ~26 mm thick layer in 20 days of melter idling.

The Mammoth Cave system, Kentucky, USA

International Nuclear Information System (INIS)

Palmer, A. N.

2016-01-01

Mammoth Cave is the main attraction of Mammoth Cave National Park. For several decades it has been the longest known cave in the world and currently contains 652 km in 2016 of surveyed passages. It is located in the heart of an extensive karst plateau, in which the stratal dip averages only one degree. The cave is part of a drainage basin of more than 200 km 2 . The cave has been known to local inhabitants for several millennia and contains a rich trove of archaeological and historical artifacts. It contains many speleo biota including several rare and endangered species and has been designated a World Heritage Site and an International Biosphere Reserve (UNESCO). Its many passage levels and sediments contain a record of the fluvial history of most of south-eastern North America. (Author)

Solar activity influence on air temperature regimes in caves

Science.gov (United States)

Stoeva, Penka; Mikhalev, Alexander; Stoev, Alexey

Cave atmospheres are generally included in the processes that happen in the external atmosphere as circulation of the cave air is connected with the most general circulation of the air in the earth’s atmosphere. Such isolated volumes as the air of caves are also influenced by the variations of solar activity. We discuss cave air temperature response to climate and solar and geomagnetic activity for four show caves in Bulgaria studied for a period of 46 years (1968 - 2013). Everyday noon measurements in Ledenika, Saeva dupka, Snezhanka and Uhlovitsa cave have been used. Temperatures of the air in the zone of constant temperatures (ZCT) are compared with surface temperatures recorded at meteorological stations situated near about the caves - in the towns of Vratsa, Lovech, Peshtera and Smolyan, respectively. For comparison, The Hansen cave, Middle cave and Timpanogos cave from the Timpanogos Cave National Monument, Utah, USA situated nearly at the same latitude have also been examined. Our study shows that the correlation between cave air temperature time series and sunspot number is better than that between the cave air temperature and Apmax indices; that t°ZCT is rather connected with the first peak in geomagnetic activity, which is associated with transient solar activity (CMEs) than with the second one, which is higher and connected with the recurrent high speed streams from coronal holes. Air temperatures of all examined show caves, except the Ledenika cave, which is ice cave show decreasing trends. On the contrary, measurements at the meteorological stations show increasing trends in the surface air temperatures. The trend is decreasing for the Timpanogos cave system, USA. The conclusion is that surface temperature trends depend on the climatic zone, in which the cave is situated, and there is no apparent relation between temperatures inside and outside the caves. We consider possible mechanism of solar cosmic rays influence on the air temperatures in caves

World Register of marine Cave Species (WoRCS: a new Thematic Species Database for marine and anchialine cave biodiversity

Directory of Open Access Journals (Sweden)

Vasilis Gerovasileiou

2016-09-01

Full Text Available Scientific exploration of marine cave environments and anchialine ecosystems over recent decades has led to outstanding discoveries of novel taxa, increasing our knowledge of biodiversity. However, biological research on underwater caves has taken place only in a few areas of the world and relevant information remains fragmented in isolated publications and databases. This fragmentation makes assessing the conservation status of marine cave species especially problematic, and this issue should be addressed urgently given the stresses resulting from planned and rampant development in the coastal zone worldwide. The goal of the World Register of marine Cave Species (WoRCS initiative is to create a comprehensive taxonomic and ecological database of known species from marine caves and anchialine systems worldwide and to present this as a Thematic Species Database (TSD of the World Register of marine Species (WoRMS. WoRCS will incorporate ecological data (e.g., type of environment, salinity regimes, and cave zone as well as geographical information on the distribution of species in cave and anchialine environments. Biodiversity data will be progressively assembled from individual database sources at regional, national or local levels, as well as from literature sources (estimate: >20,000 existing records of cave-dwelling species scattered in several databases. Information will be organized in the WoRCS database following a standard glossary based on existing terminology. Cave-related information will be managed by the WoRCS thematic editors with all data dynamically linked to WoRMS and its team of taxonomic editors. In order to mobilize data into global biogeographic databases, a Gazetteer of the Marine and Anchialine Caves of the World will be established. The presence records of species could be eventually georeferenced for submission to the Ocean Biogeographic Information System (OBIS and constitute an important dataset for biogeographical and

Reproductive Seasonality in Nesticus (Araneae: Nesticidae) Cave Spiders.

Science.gov (United States)

Carver, Linnea M; Perlaky, Patricia; Cressler, Alan; Zigler, Kirk S

2016-01-01

Spiders of the family Nesticidae are members of cave communities around the world with cave-obligate (troglobiotic) species known from North America, Europe, Asia and the Indo-Pacific. A radiation of Nesticus (Araneae: Nesticidae) in the southern Appalachians includes ten troglobiotic species. Many of these species are of conservation interest due to their small ranges, with four species being single-cave endemics. Despite conservation concerns and their important role as predators in cave communities, we know little about reproduction and feeding in this group. We addressed this knowledge gap by examining populations of two species on a monthly basis for one year. We made further observations on several other species and populations, totaling 671 individual spider observations. This more than doubled the reported observations of reproduction and feeding in troglobiotic Nesticus. Female Nesticus carry egg sacs, facilitating the determination of the timing and frequency of reproduction. We found that Nesticus exhibit reproductive seasonality. Females carried egg sacs from May through October, with a peak in frequency in June. These spiders were rarely observed with prey; only 3.3% (22/671) of individuals were observed with prey items. The frequency at which prey items were observed did not vary by season. Common prey items were flies, beetles and millipedes. Troglobiotic species constituted approximately half of all prey items observed. This result represents a greater proportion of troglobiotic prey than has been reported for various troglophilic spiders. Although our findings shed light on the life history of troglobiotic Nesticus and on their role in cave ecosystems, further work is necessary to support effective conservation planning for many of these rare species.

An Investigation of Meromixis in Cave Pools, Lechuguilla Cave, New Mexico.

Directory of Open Access Journals (Sweden)

David B. Levy

2008-07-01

Full Text Available Chemical characteristics of permanent stratification in cave pools (meromixis may provide insight into the geochemical origin and evolution of cave pool waters. The objective of this study was to test the hypothesis that some pools in Lechuguilla Cave may be subject to ectogenic meromixis, where permanent chemical stratification is induced by input of relatively saline or fresh water from an external source. However, because organic C concentrations in Lechuguilla waters are low (typically 0.9 m, and are probably the result of localized and transient atmospheric CO2(g concentrations. At LOBG, an EC increase of 93 µS cm-1 at the 0.9-m depth suggests meromictic conditions which are ectogenic, possibly due to surface inflow of fresh water as drips or seepage into a pre-existing layer of higher salinity.

Spray Calciner/In-Can Melter high-level waste solidification technical manual

International Nuclear Information System (INIS)

Larson, D.E.

1980-09-01

This technical manual summarizes process and equipment technology developed at Pacific Northwest Laboratory over the last 20 years for vitrification of high-level liquid waste by the Spray Calciner/In-Can Melter process. Pacific Northwest Laboratory experience includes process development and demonstration in laboratory-, pilot-, and full-scale equipment using nonradioactive synthetic wastes. Also, laboratory- and pilot-scale process demonstrations have been conducted using actual high-level radioactive wastes. In the course of process development, more than 26 tonnes of borosilicate glass have been produced in 75 canisters. Four of these canisters contained radioactive waste glass. The associated process and glass chemistry is discussed. Technology areas described include calciner feed treatment and techniques, calcination, vitrification, off-gas treatment, glass containment (the canister), and waste glass chemistry. Areas of optimization and site-specific development that would be needed to adapt this base technology for specific plant application are indicated. A conceptual Spray Calciner/In-Can Melter system design and analyses are provided in the manual to assist prospective users in evaluating the process for plant application, to provide equipment design information, and to supply information for safety analyses and environmental reports. The base (generic) technology for the Spray Calciner/In-Can Melter process has been developed to a point at which it is ready for plant application

Hydrological characterization of cave drip waters in a porous limestone: Golgotha Cave, Western Australia

Science.gov (United States)

Mahmud, Kashif; Mariethoz, Gregoire; Baker, Andy; Treble, Pauline C.

2018-02-01

Cave drip water response to surface meteorological conditions is complex due to the heterogeneity of water movement in the karst unsaturated zone. Previous studies have focused on the monitoring of fractured rock limestones that have little or no primary porosity. In this study, we aim to further understand infiltration water hydrology in the Tamala Limestone of SW Australia, which is Quaternary aeolianite with primary porosity. We build on our previous studies of the Golgotha Cave system and utilize the existing spatial survey of 29 automated cave drip loggers and a lidar-based flow classification scheme, conducted in the two main chambers of this cave. We find that a daily sampling frequency at our cave site optimizes the capture of drip variability with the least possible sampling artifacts. With the optimum sampling frequency, most of the drip sites show persistent autocorrelation for at least a month, typically much longer, indicating ample storage of water feeding all stalactites investigated. Drip discharge histograms are highly variable, showing sometimes multimodal distributions. Histogram skewness is shown to relate to the wetter-than-average 2013 hydrological year and modality is affected by seasonality. The hydrological classification scheme with respect to mean discharge and the flow variation can distinguish between groundwater flow types in limestones with primary porosity, and the technique could be used to characterize different karst flow paths when high-frequency automated drip logger data are available. We observe little difference in the coefficient of variation (COV) between flow classification types, probably reflecting the ample storage due to the dominance of primary porosity at this cave site. Moreover, we do not find any relationship between drip variability and discharge within similar flow type. Finally, a combination of multidimensional scaling (MDS) and clustering by k means is used to classify similar drip types based on time series

Hydrological characterization of cave drip waters in a porous limestone: Golgotha Cave, Western Australia

Directory of Open Access Journals (Sweden)

K. Mahmud

2018-02-01

Full Text Available Cave drip water response to surface meteorological conditions is complex due to the heterogeneity of water movement in the karst unsaturated zone. Previous studies have focused on the monitoring of fractured rock limestones that have little or no primary porosity. In this study, we aim to further understand infiltration water hydrology in the Tamala Limestone of SW Australia, which is Quaternary aeolianite with primary porosity. We build on our previous studies of the Golgotha Cave system and utilize the existing spatial survey of 29 automated cave drip loggers and a lidar-based flow classification scheme, conducted in the two main chambers of this cave. We find that a daily sampling frequency at our cave site optimizes the capture of drip variability with the least possible sampling artifacts. With the optimum sampling frequency, most of the drip sites show persistent autocorrelation for at least a month, typically much longer, indicating ample storage of water feeding all stalactites investigated. Drip discharge histograms are highly variable, showing sometimes multimodal distributions. Histogram skewness is shown to relate to the wetter-than-average 2013 hydrological year and modality is affected by seasonality. The hydrological classification scheme with respect to mean discharge and the flow variation can distinguish between groundwater flow types in limestones with primary porosity, and the technique could be used to characterize different karst flow paths when high-frequency automated drip logger data are available. We observe little difference in the coefficient of variation (COV between flow classification types, probably reflecting the ample storage due to the dominance of primary porosity at this cave site. Moreover, we do not find any relationship between drip variability and discharge within similar flow type. Finally, a combination of multidimensional scaling (MDS and clustering by k means is used to classify similar drip

Occupational exposure to radon in Australian Tourist Caves an Australian-wide study of radon levels

Energy Technology Data Exchange (ETDEWEB)

Solomon, S B; Langroo, R; Peggie, J R [Australian Radiation Laboratory. Yallambie, VIC (Australia); Lyons, R G [University of Auckland, Auckland, (New Zealand). Department of Physics; James, J M [University of Sydney, Sydney, NSW (Australia). Department of Chemisty

1996-02-01

The study described in this report sets out to determine which Australian show caves have long- term radon levels in excess of the proposed action level of 1000 Bq m{sup -3}. The collaborative study between the Australian Radiation Laboratory (ARL), the University of Sydney and the University of Auckland, was carried out with the support of a Research Grant from Worksafe Australia. The aims of this study were to measure radon levels for each season over a period of one year, at representative sites in all developed show caves around Australia, to determine yearly average radon levels for each cave tour, based on these site measurements, to estimate the radiation doses to the tour guides employed in these caves, and to identify caves with radon concentrations in excess of the action level. (authors) 7 refs., 10 tabs., 2 figs.

An absolutely dated high-resolution stalagmite record from Lianhua Cave in central China: Climate forcing and comparison with Wanxiang Cave and Dongge Cave records over the past 2000 years

Science.gov (United States)

Li, Hong-Chun; Yin, Jian-Jun; Shen, Chuan-Chou; Mii, Horng-Sheng; Li, Ting-Yong

2015-04-01

A 33-cm long aragonite stalagmite (LHD-1) from Lianhua Cave has been dated by MC-ICPMS 230Th/U method on 41 horizons. Very high U contents (1~6ppm) and low Th contents yield excellent 230Th/U dates which provide reliable chronology of the stalagmite on sub-decadal time scale over the past 3350 years. A total of 1716 samples have been measured for δ18O and δ13C, spanning annual resolution over the past 1820 years. The stalagmite δ18O is not only influenced by the 'amount effect', but also affected by the moisture source. Enhanced the tropical monsoon trough under strong EASM brings higher spring quarter rainfall with isotopically light monsoonal moisture in the cave site, resulting in lighter stalagmite δ18O. On decadal or longer time scales, increased solar activity produces warmer condition and stronger summer monsoon which lead to wet climates. On interannual-to-decadal scales, the Walker Circulation under El Niño conditions during cold periods will shift toward the central Pacific and result in weakening of EASM. Under such a circumstance, dry climates will be prevailed in the study area. Based on the δ18O and δ13C records, we have deciphered climatic and vegetation changes of the study area in decadal scales. The highly precise dated LHD-1 record has been compared with previous published Wanxiang Cave and Dongge Cave records. Although some similarities can be found, there are major discrepancies among the three well-dated records, especially during AD 500-700 and AD 1300-1600. In additional, the major weak monsoon periods defined in the Wanxiang Cave record during late Tang Dynasty, late Yuan Dynasty and late Ming Dynasty are not supported by the LHD-1 record. The heaviest δ18O peaks (more than five continuous heavy values) over the past 2000 years appeared around AD 1990-2003, 1657-1662, 1220-1228, 663-669, 363-370, and 1082-1090 (in the order of heavy to light). None of these periods occurred Chinese dynasty collapse.

Final Report Tests On The Duramelter 1200 HLW Pilot Melter System Using AZ-101 HLW Simulants VSL-02R0100-2, Rev. 1, 2/17/03

International Nuclear Information System (INIS)

Kruger, A.A.; Matlack, K.S.; Kot, W.K.; Bardakci, T.; Gong, W.; D'Angelo, N.A.; Schatz, T.R.; Pegg, I.L.

2011-01-01

This document provides the final report on data and results obtained from a series of nine tests performed on the one-third scale DuraMelter(trademark) 1200 (DM1200) HLW Pilot Melter system that has been installed at VSL with an integrated prototypical off-gas treatment system. That system has replaced the DM1000 system that was used for HLW throughput testing during Part B1 (1). Both melters have similar melt surface areas (1.2 m 2 ) but the DM1200 is prototypical of the present RPP-WTP HLW melter design whereas the DM1000 was not. These tests were performed under a corresponding RPP-WTP Test Specification and associated Test Plans. The nine tests reported here were preceded by an initial series of short-duration tests conducted to support the start-up and commissioning of this system. This report is a followup to the previously issued Preliminary Data Summary Reports. The DM1200 system was deployed for testing and confirmation of basic design, operability, flow sheet, and process control assumptions as well as for support of waste form qualification and permitting. These tests include data on processing rates, off-gas treatment system performance, recycle stream compositions, as well as process operability and reliability. Consequently, this system is a key component of the overall HLW vitrification development strategy. The primary objective of the present series of tests was to determine the effects of a variety of parameters on the glass production rate in comparison to the RPP-WTP HL W design basis of 400 kg/m 2 /d. Previous testing on the DMIOOO system (1) concluded that achievement of that rate with simulants of projected WTP melter feeds (AZ-101 and C-106/AY-102) was unlikely without the use of bubblers. As part of those tests, the same feed that was used during the cold-commissioning of the West Valley Demonstration Project (WVDP) HLW vitrification system was run on the DM1000 system. The DM1000 tests reproduced the rates that were obtained at the larger

FINAL REPORT TESTS ON THE DURAMELTER 1200 HLW PILOT MELTER SYSTEM USING AZ-101 HLW SIMULANTS VSL-02R0100-2 REV 1 2/17/03

Energy Technology Data Exchange (ETDEWEB)

KRUGER AA; MATLACK KS; KOT WK; BARDAKCI T; GONG W; D' ANGELO NA; SCHATZ TR; PEGG IL

2011-12-29

This document provides the final report on data and results obtained from a series of nine tests performed on the one-third scale DuraMelter{trademark} 1200 (DM1200) HLW Pilot Melter system that has been installed at VSL with an integrated prototypical off-gas treatment system. That system has replaced the DM1000 system that was used for HLW throughput testing during Part B1 [1]. Both melters have similar melt surface areas (1.2 m{sup 2}) but the DM1200 is prototypical of the present RPP-WTP HLW melter design whereas the DM1000 was not. These tests were performed under a corresponding RPP-WTP Test Specification and associated Test Plans. The nine tests reported here were preceded by an initial series of short-duration tests conducted to support the start-up and commissioning of this system. This report is a followup to the previously issued Preliminary Data Summary Reports. The DM1200 system was deployed for testing and confirmation of basic design, operability, flow sheet, and process control assumptions as well as for support of waste form qualification and permitting. These tests include data on processing rates, off-gas treatment system performance, recycle stream compositions, as well as process operability and reliability. Consequently, this system is a key component of the overall HLW vitrification development strategy. The primary objective of the present series of tests was to determine the effects of a variety of parameters on the glass production rate in comparison to the RPP-WTP HL W design basis of 400 kg/m{sup 2}/d. Previous testing on the DMIOOO system [1] concluded that achievement of that rate with simulants of projected WTP melter feeds (AZ-101 and C-106/AY-102) was unlikely without the use of bubblers. As part of those tests, the same feed that was used during the cold-commissioning of the West Valley Demonstration Project (WVDP) HLW vitrification system was run on the DM1000 system. The DM1000 tests reproduced the rates that were obtained at the

Sediments of Biśnik Cave (Poland): Lithology and stratigraphy of the Middle Palaeolithic site

Czech Academy of Sciences Publication Activity Database

Krajcarz, M. T.; Bosák, Pavel; Šlechta, Stanislav; Pruner, Petr; Komar, M.; Dresler, J.; Madeyska, T.

326/327, April (2014), s. 6-19 ISSN 1040-6182 R&D Projects: GA AV ČR IAA300130701 Institutional research plan: CEZ:AV0Z30130516 Institutional support: RVO:67985831 Keywords : karsology * caves * Biśnik Cave (Poland) Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.062, year: 2014

Discovery of a diverse cave flora in China

Science.gov (United States)

Wen, Fang

2018-01-01

Few studies document plants in caves. Our field observations of a widespread and seemingly angiosperm-rich cave flora in SW China lead us to test the following hypotheses, 1) SW China caves contain a diverse vascular plant flora, 2) that this is a relic of a largely absent forest type lacking endemic species, and 3) that the light environment plants occupy in caves is not distinct from non-cave habitats. To do so we surveyed 61 caves and used species accumulation curves (SAC) to estimate the total diversity of this flora and used a subsample of 14 caves to characterise the light environment. We used regional floras and existing conservation assessments to evaluate the conservation value of this flora. We used observations on human disturbance within caves to evaluate anthropogenic activities. Four-hundred-and-eighteen vascular plant species were documented with SACs predicting a total diversity of 529–846. Ninety-three percent of the species documented are known karst forest species, 7% are endemic to caves and 81% of the species are angiosperms. We demonstrate that the light environment in caves is distinct to that of terrestrial habitats and that a subset of the flora likely grow in the lowest light levels documented for vascularised plants. Our results suggest that the proportion of species threatened with extinction is like that for the terrestrial habitat and that almost half of the entrance caverns sampled showed signs of human disturbance. We believe that this is the first time that such an extensive sample of cave flora has been undertaken and that such a diverse vascular plant flora has been observed in caves which we predict occurs elsewhere in SE Asia. We argue that the cave flora is an extension of the karst forest understory present prior to catastrophic deforestation in the 20thC. We suggest that within SW China caves serve as both refuges and a valuable source of germplasm for the restoration of karst forest. We also propose that caves represent a

Discovery of a diverse cave flora in China.

Science.gov (United States)

Monro, Alexandre K; Bystriakova, Nadia; Fu, Longfei; Wen, Fang; Wei, Yigang

2018-01-01

Few studies document plants in caves. Our field observations of a widespread and seemingly angiosperm-rich cave flora in SW China lead us to test the following hypotheses, 1) SW China caves contain a diverse vascular plant flora, 2) that this is a relic of a largely absent forest type lacking endemic species, and 3) that the light environment plants occupy in caves is not distinct from non-cave habitats. To do so we surveyed 61 caves and used species accumulation curves (SAC) to estimate the total diversity of this flora and used a subsample of 14 caves to characterise the light environment. We used regional floras and existing conservation assessments to evaluate the conservation value of this flora. We used observations on human disturbance within caves to evaluate anthropogenic activities. Four-hundred-and-eighteen vascular plant species were documented with SACs predicting a total diversity of 529-846. Ninety-three percent of the species documented are known karst forest species, 7% are endemic to caves and 81% of the species are angiosperms. We demonstrate that the light environment in caves is distinct to that of terrestrial habitats and that a subset of the flora likely grow in the lowest light levels documented for vascularised plants. Our results suggest that the proportion of species threatened with extinction is like that for the terrestrial habitat and that almost half of the entrance caverns sampled showed signs of human disturbance. We believe that this is the first time that such an extensive sample of cave flora has been undertaken and that such a diverse vascular plant flora has been observed in caves which we predict occurs elsewhere in SE Asia. We argue that the cave flora is an extension of the karst forest understory present prior to catastrophic deforestation in the 20thC. We suggest that within SW China caves serve as both refuges and a valuable source of germplasm for the restoration of karst forest. We also propose that caves represent a

Radon survey in caves from Mallorca Island, Spain

Energy Technology Data Exchange (ETDEWEB)

Dumitru, Oana A. [Department of Geology, Babeș-Bolyai University, Kogălniceanu 1, 400084 Cluj-Napoca (Romania); School of Geosciences, University of South Florida, 4202 E. Fowler Ave., NES 107 Tampa (United States); Onac, Bogdan P. [School of Geosciences, University of South Florida, 4202 E. Fowler Ave., NES 107 Tampa (United States); Fornós, Joan J. [Departament de Ciències de la Terra, Universitat de les Illes Balears, Crta. Valldemossa km 7.5, 07122 Palma (Mallorca) (Spain); Cosma, Constantin [Environmental Radioactivity and Nuclear Dating Center, Babeș-Bolyai University, Fântânele 30, 400294 Cluj-Napoca (Romania); Ginés, Angel; Ginés, Joaquín [Departament de Ciències de la Terra, Universitat de les Illes Balears, Crta. Valldemossa km 7.5, 07122 Palma (Mallorca) (Spain); Merino, Antoni [Grup Espeleològic de Llubí, Federació Balear d' Espeleologia, c/Uruguai s/n, Palma Arena, 07010 Palma, Illes Balears (Spain)

2015-09-01

This study reports radon concentration in the most representative caves of Mallorca, identifying those in which the recommended action level is exceeded, thus posing health risks. Two show caves (Campanet and Artà) and three non-touristic caves (Font, Drac, Vallgornera) were investigated. Data were collected at several locations within each cave for three different periods, from March 2013 to March 2014. Except for Vallgornera, where only one monitoring period was possible, and Artà in which low values were recorded throughout the year, a clear seasonal variability, with higher values during the warm seasons and lower during winter time is prominent. Radon concentrations differed markedly from one cave to another, as well as within the same cave, ranging from below detection limit up to 3060 Bq·m{sup −3}. The results of this study have significant practical implications, making it possible to provide some recommendation to cave administrators and other agencies involved in granting access to the investigated caves. - Highlights: • A survey of radon was carried out in caves from Mallorca, Spain using CR 39 detectors. • Three different seasons are covered: spring, summer, and winter. • Radon level ranges from below detection limit up to 3060 Bq·m{sup −3}. • Seasonal variation is evident (higher values in summer and lower during winter). • Particular recommendations were made to each cave administration.

Paleo-watertable definition using cave ferromanganese stromatolites and associated cave-wall notches (Sierra de Arnero, Spain)

Science.gov (United States)

Rossi, Carlos; Villalaín, Juan J.; Lozano, Rafael P.; Hellstrom, John

2016-05-01

The steeply-dipping-dolostone-hosted caves of the Sierra de Arnero (N Spain) contain low-gradient relict canyons with up to ten mapped levels of ferromanganese stromatolites and associated wall notches over a vertical range of 85 m, the highest occurring 460 m above base level. Despite a plausible speleogenetic contribution by pyrite oxidation, and the irregular cave-wall mesomorphologies suggestive of hypogenic speleogenesis, the Arnero relict caves are dominantly epigenic, as indicated by the conduit pattern and the abundant allogenic sediments. Allogenic input declined over time due to a piracy-related decrease in the drainage area of allogenic streams, explaining the large size of the relict Arnero caves relative to the limited present-day outcrop area of the karstified carbonates. Allogenic-sediment input also explains the observed change from watertable canyons to phreatic conduits in the paleo-downstream direction. Stromatolites and notches arguably formed in cave-stream passages at the watertable. The best-defined paleo-watertables show an overall slope of 1.7°, consistent with the present-day relief of the watertable, with higher-slope segments caused by barriers related to sulfide mineralization. The formation of watertable stromatolites favored wall notching by the combined effect of enhanced acidity by Mn-Fe oxidation and shielding of cave floors against erosion. Abrasive bedload further contributed to notch formation by promoting lateral mechanical erosion and protecting passage floors. The irregular wallrock erosional forms of Arnero caves are related partly to paragenesis and partly to the porous nature of the host dolostones, which favored irregular dissolution near passage walls, generating friable halos. Subsequent mechanical erosion contributed to generate spongework patterns. The dolostone porosity also contributes to explain the paradox that virtually all Arnero caves are developed in dolostone despite being less soluble than adjacent

FEASIBILITY EVALUATION AND RETROFIT PLAN FOR COLD CRUCIBLE INDUCTION MELTER DEPLOYMENT IN THE DEFENSE WASTE PROCESSING FACILITY AT SAVANNAH RIVER SITE 8118

International Nuclear Information System (INIS)

Barnes, A; Dan Iverson, D; Brannen Adkins, B

2008-01-01

increase heat transfer to the slurry fed High Level Waste (HLW) sludge, the CCIM may be equipped with bubblers and/or water cooled mechanical agitators. The DWPF could benefit from use of CCIM technology, especially in light of our latest projections of waste volume to be vitrified. Increased waste loading and increased throughput could result in substantial life cycle cost reduction. In order to significantly surpass the waste throughput capability of the currently installed JHM, it may be necessary to install two 950 mm CCIMs in the DWPF Melt Cell. A cursory evaluation of system design requirements and modifications to the facility that may be required to support installation and operation of two 950 mm CCIMs was performed. Based on this evaluation, it appears technically feasible to position two CCIMs in the Melt Cell of the DWPF within the existing footprint of the current melter. Interfaces with support systems and controls including Melter Feed, Power, Melter Cooling Water, Melter Off-gas, and Canister Operations must be designed to support dual CCIM operations. This paper describes the CCIM technology and identifies technical challenges that must be addressed in order to implement CCIMs in the DWPF

Startup of a Joule-heated glass melter with a graphite slurry

International Nuclear Information System (INIS)

Allen, T.L.; Routt, K.R.; Porter, M.A.

1983-01-01

This paper discusses the theoretical equations and physical and electrical property data of various graphite slurries for starting up a glass melter. An application test is also included to demonstrate the graphite slurry startup technique

Book Review: Caves and Karst of the Yorkshire Dales

Science.gov (United States)

Westaway, Rob

2015-10-01

The British Cave Research Association (BCRA) is the research division of the British Caving Association (BCA), itself the principal society in Britain for those interested in caving, with activities including provision of training and safety certification for cavers and managing access to caves. Although some UK cave-related research is carried out by academics, this tends to be restricted to archaeological investigations of caves that have served as human habitations, and to be focused more on the occupants than the caves themselves. In contrast, most cave exploration is undertaken as a leisure activity, under the auspices of clubs affiliated to the BCA/BCRA, this being indeed virtually the only field of Earth science where amateur investigators can continue to make significant discoveries. Many cave explorers are also affiliated with academic researchers, such as managers of dating laboratories; the synergy between these two groups is highly productive, having resulted for instance in the discovery and exploration in recent years of the vast Ogof Draenen cave system in South Wales, which probably dates back to the Early Pleistocene (e.g., Farrant et al., 2014).

Melting characteristics of a plasma torch melter according to the waste feeding method

International Nuclear Information System (INIS)

Kim, T. W.; Choi, J. R.; Park, S. C.; Lu, C. S.; Park, J. K.; Hwang, T. W.; Shin, S. W.

2001-01-01

By using a batch type plasma torch melting system, continuous feeding and melting tests of non-combustible waste were executed. Using the results, the establishment of a heat transfer model and its verification were executed; the characteristics of the molten slag, exhaust gas, fly dust, volatilization of Cs, and leaching of slag were analyzed. In order to establish the heat transfer mode, the followings were considered; the electrical energy supplied to the plasma torch, the absorbed energy to the plasma torch for generating the plasma gas, the absorbed energy to the cooling water of the plasma torch, the energy supplied to the melter from the plasma gas by radiant heat, the energy loss through the exhaust gas, the waste melting energy, and the heating energy of an inner crucible and the melter. The concrete and soil were melted for the verification of the model. The waste was fed through waste feeder by the amount of 0.5kg or 1kg that was calculated by using the model. The experiment for the verification resulted in that the model was fitted well until the melter was heated sufficiently. If the electrical energy of 128kW were supplied to the plasma torch, energy balance of the plasma melting system was calculated with the model: the absorbed energy to the plasma torch for generating the plasma gas (27kW), the absorbed energy to the cooling water of the plasma torch (0∼ 36kW), the energy loss through the exhaust gas (5 ∼ 8kW), the waste melting energy (14kW), and the heating energy of an inner crucible and the melter (82 ∼ 43kW)

Immobilization of high-level defense waste in a slurry-fed electric glass melter

International Nuclear Information System (INIS)

Brouns, R.A.; Mellinger, G.B.; Nelson, T.A.; Oma, K.H.

1980-11-01

Scoping studies have been performed at the Pacific Northwest Laboratory related to the direct liquid-feeding of a generic high-level defense waste to a joule-heated ceramic melter. Tests beginning on the laboratory scale and progressing to full-scale operation are reported. Laboratory work identified the need for a reducing agent in the feed to help control the foaming tendencies of the waste glass. These tests also indicated that suspension agents were helpful in reducing the tendency of solids to settle out of the liquid feed. Testing was then moved to a larger pilot-scale melter (designed for approx. 2.5 kg/h) where verification of the flowsheet examined in the lab was accomplished. It was found that the reducing agent controlled foaming and did not result in the precipitation of metals. Pumping problems were encountered when slurries with higher than normal solids content were fed. A demonstration (designed for approx. 50 kg/h) in a full-scale melter was then made with the tested flowsheet; however, the amount of reducing agent had to be increased. In addition, it was found that feed control needed further development; however, steady-state operation was achieved giving encouraging results on process capacities. During steady-state operation, ruthenium losses to the offgas system averaged less than 0.16%, while cesium losses were somewhat higher, ranging from 0.91 to 24% and averaging 13%. Particulate decontamination factors from feed to offgas in the melter ranged from 5 x 10 2 to greater than 10 3 without any filtration or treatment. Approximately 1050 kg of glass was produced from 2900 L of waste at rates up to 40 kg/h

Baseline tests for arc melter vitrification of INEL buried wastes. Volume 1: Facility description and summary data report

International Nuclear Information System (INIS)

Oden, L.L.; O'Connor, W.K.; Turner, P.C.; Soelberg, N.R.; Anderson, G.L.

1993-01-01

This report presents field results and raw data from the Buried Waste Integrated Demonstration (BWID) Arc Melter Vitrification Project Phase 1 baseline test series conducted by the Idaho National Engineering Laboratory (INEL) in cooperation with the U.S. Bureau of Mines (USBM). The baseline test series was conducted using the electric arc melter facility at the USBM Albany Research Center in Albany, Oregon. Five different surrogate waste feed mixtures were tested that simulated thermally-oxidized, buried, TRU-contaminated, mixed wastes and soils present at the INEL. The USBM Arc Furnace Integrated Waste Processing Test Facility includes a continuous feed system, the arc melting furnace, an offgas control system, and utilities. The melter is a sealed, 3-phase alternating current (ac) furnace approximately 2 m high and 1.3 m wide. The furnace has a capacity of 1 metric ton of steel and can process as much as 1,500 lb/h of soil-type waste materials. The surrogate feed materials included five mixtures designed to simulate incinerated TRU-contaminated buried waste materials mixed with INEL soil. Process samples, melter system operations data and offgas composition data were obtained during the baseline tests to evaluate the melter performance and meet test objectives. Samples and data gathered during this program included (a) automatically and manually logged melter systems operations data, (b) process samples of slag, metal and fume solids, and (c) offgas composition, temperature, velocity, flowrate, moisture content, particulate loading and metals content. This report consists of 2 volumes: Volume I summarizes the baseline test operations. It includes an executive summary, system and facility description, review of the surrogate waste mixtures, and a description of the baseline test activities, measurements, and sample collection. Volume II contains the raw test data and sample analyses from samples collected during the baseline tests

DM100 AND DM1200 MELTER TESTING WITH HIGH WASTE LOADING FORMULATIONS FOR HANFORD HIGH-ALUMINUM HLW STREAMS, TEST PLAN 09T1690-1

International Nuclear Information System (INIS)

Kruger, A.A.; Matlack, K.S.; Kot, W.K.; Pegg, I.L.; Joseph, I.

2009-01-01

This Test Plan describes work to support the development and testing of high waste loading glass formulations that achieve high glass melting rates for Hanford high aluminum high level waste (HLW). In particular, the present testing is designed to evaluate the effect of using low activity waste (LAW) waste streams as a source of sodium in place ofchemical additives, sugar or cellulose as a reductant, boehmite as an aluminum source, and further enhancements to waste processing rate while meeting all processing and product quality requirements. The work will include preparation and characterization of crucible melts in support of subsequent DuraMelter 100 (DM 100) tests designed to examine the effects of enhanced glass formulations, glass processing temperature, incorporation of the LAW waste stream as a sodium source, type of organic reductant, and feed solids content on waste processing rate and product quality. Also included is a confirmatory test on the HLW Pilot Melter (DM1200) with a composition selected from those tested on the DM100. This work builds on previous work performed at the Vitreous State Laboratory (VSL) for Department of Energy's (DOE's) Office of River Protection (ORP) to increase waste loading and processing rates for high-iron HLW waste streams as well as previous tests conducted for ORP on the same waste composition. This Test Plan is prepared in response to an ORP-supplied statement of work. It is currently estimated that the number of HLW canisters to be produced in the Hanford Tank Waste Treatment and Immobilization Plant (WTP) is about 12,500. This estimate is based upon the inventory ofthe tank wastes, the anticipated performance of the sludge treatment processes, and current understanding of the capability of the borosilicate glass waste form. The WTP HLW melter design, unlike earlier DOE melter designs, incorporates an active glass bubbler system. The bubblers create active glass pool convection and thereby improve heat transfer and

Final Report - Glass Formulation Testing to Increase Sulfate Volatilization from Melter, VSL-04R4970-1, Rev. 0, dated 2/24/05

Energy Technology Data Exchange (ETDEWEB)

Kruger, Albert A.; Matlack, K. A.; Pegg, I. L.; Gong, W.

2013-11-13

The principal objectives of the DM100 and DM10 tests were to determine the impact of four different organics and one inorganic feed additive on sulfate volatilization and to determine the sulfur partitioning between the glass and the off-gas system. The tests provided information on melter processing characteristics and off-gas data including sulfur incorporation and partitioning. A series of DM10 and DM100 melter tests were conducted using a LAW Envelope A feed. The testing was divided into three parts. The first part involved a series of DM10 melter tests with four different organic feed additives: sugar, polyethylene glycol (PEG), starch, and urea. The second part involved two confirmatory 50-hour melter tests on the DM100 using the best combination of reductants and conditions based on the DM10 results. The third part was performed on the DM100 with feeds containing vanadium oxide (V{sub 2}O{sub 5}) as an inorganic additive to increase sulfur partitioning to the off-gas. Although vanadium oxide is not a reductant, previous testing has shown that vanadium shows promise for partitioning sulfur to the melter exhaust, presumably through its known catalytic effect on the SO{sub 2}/SO{sub 3} reaction. Crucible-scale tests were conducted prior to the melter tests to confirm that the glasses and feeds would be processable in the melter and that the glasses would meet the waste form (ILAW) performance requirements. Thus, the major objectives of these tests were to: Perform screening tests on the DM10 followed by tests on the DM100-WV system using a LAW -Envelope A feed with four organic additives to assess their impact on sulfur volatilization. Perform tests on the DM100-WV system using a LAW -Envelope A feed containing vanadium oxide to assess its impact on sulfur volatilization. Determine feed processability and product quality with the above additives. Collect melter emissions data to determine the effect of additives on sulfur partitioning and melter emissions

Formulation of special glass frit and its use for decontamination of Joule melter employed for vitrification of high level and radioactive liquid waste

International Nuclear Information System (INIS)

Valsala, T.P.; Mishra, P.K.; Thakur, D.A.; Ghongane, D.E.; Jayan, R.V.; Dani, U.; Sonavane, M.S.; Kulkarni, Y.

2012-01-01

Advanced vitrification system at TWMP Tarapur was used for successful vitrification of large volume of HLW stored in waste tank farm. After completion of the operational life of the joule melter, dismantling was planned. Prior to the dismantling, the hold up inventory of active glass product from the melter was flushed out using specially formulated inactive glass frit to reduce the air activity buildup in the cell during dismantling operations. The properties of the special glass frit prepared are comparable with that of the regular product glass. More than 94% of holdup activity was flushed out from the joule melter prior to the dismantling of the melter. (author)

PIXE analysis of cave sediments, prehispanic paintings and obsidian cutting tools from Baja California Sur caves

International Nuclear Information System (INIS)

Miranda, J.; Oliver, A.; Dacal, A.; Ruvalcaba, J.L.; Cruz, F.; Ortiz, M.E.; Vinas, R.

1993-01-01

Elemental PIXE analysis of cave sediments, minerals, pigments of the prehispanic paintings and obsidian cutting tools from caves in Baja California Sur has been carried out with a 0.7 MeV proton beam. The elements analysed in this sample set (Al to Co) provide an idea of the environment of the caves. The obsidian data analysis suggests that the human communities who made these painting used more than one obsidian source to manufacture cutting tools. (orig.)

The dismantling of the one-third-scale Joule ceramic melter and preliminary investigation of electrode corrosion

International Nuclear Information System (INIS)

Morris, J.B.; Walmsley, D.; Hollinrake, A.; Horsley, G.

1986-01-01

The Harwell one-third scale Joule ceramic melter was dismantled to discover the cause of a fall in electric resistance. The two inconel-690 electrodes were corroded over the lower 40mm sections and were examined by optical and electron microscopy. Sedimentation of Ru species on the floor of the melter may have led to corrosion of the electrodes. Glass withdrawn from the canisters was analyzed for evidence of a segregation mechanism. (UK)

Exposure to radon in Australian tourist caves

International Nuclear Information System (INIS)

Solomon, S.B.; Langroo, R.; Lyons, R.G.

1994-01-01

In 1991 the International Commission on Radiological Protection(ICRP) produced guidelines and recommendations dealing with workplace exposure to elevated background radiation, in particular, the risk associated with the inhalation of radon and radon progeny. An intervention level of 1000 Bq m -3 has been proposed. Australia has over 40 tourist caves, under the management of the various State Departments or private groups. The limited data available on radon levels in Australian caves would suggest that some of these caves may be in excess of the proposed intervention level, thus presenting a potential health risk for the cave guides. This paper summarises the current information on radon in Australian caves and describes the proposed methodologies to be used for a Worksafe Australia-funded survey of radon levels in Tourist caves within Australia. This survey is to be carried out jointly by researchers at the Australian Radiation Laboratory, University of Auckland and the University of Sydney, during 1994 and 1995. 7 refs., 3 tabs

Diversity of cultivable bacteria involved in the formation of macroscopic microbial colonies (Cave silver on the walls of a cave in Slovenia

Directory of Open Access Journals (Sweden)

Blagajana Herzog Velikonja

2014-01-01

Full Text Available Karstic caves often support white, yellow, grey or pink microbial colonies that are termed ‘cave silver’ by speleologists. Using various sample pre-treatments and culture media, a wide variety of bacteria associated with these colonies were recovered from a cave in Slovenia, Pajsarjeva jama. Decreasing the inoculum size resulted in significant increases in viable counts, while pre-treatments had the opposite effect with the exception of microwave irradiation. While all growth media yielded viable counts, the maximal counts were observed on a low-nutrient TWA medium. Based on the 16S rRNA gene sequence of OTU representatives, the majority of the 80 isolates examined belonged to Streptomyces (25%, Micrococcus (16% and Rhodococcus (10% Other abundant groups were Pseudomonas (9%, Agrobacterium (8%, Lysobacter (6% and Paenibacillus (5%, while members of genera Microbacterium, Agrococcus, Arthrobacter, Bacillus, Kocuria, Oerskovia, Sphingomonas, Aerococcus, and Bosea represented a minor portion of cultivable diversity encountered. Members of Streptomyces and Agrobacterium were common to all samples. Although these microorganisms readily form colonies under laboratory conditions, they were unrelated to abundant environmental phylotypes recovered from same samples in a previous study. However, the comparative 16S rRNA analysis showed that microorganisms highly related to the ones obtained in this study were cultivated from other subterranean environments indicating that they might represent true microbial cave dwellers.

Minerogenetic mechanisms occurring in the cave environment: an overview

Directory of Open Access Journals (Sweden)

Forti Paolo

2011-07-01

Full Text Available Perhaps man’s first motivation to explore caves, beyond using them as shelter, was the search for substances that were not availableelsewhere: most of them were minerals. However, for a long time it was believed that the cave environment was not very interestingfrom the mineralogical point of view. This was due to the fact that most cave deposits are normally composed of a singlecompound: calcium carbonate. Therefore, the systematic study of cave mineralogy is of only recent origin. However, although onlya limited number of natural cavities have been investigated in detail, about 350 cave minerals have already been observed, someof which are new to science. The presence of such unexpected richness is a direct consequence of the variety of rocks traversedby water or other fluids before entering a cave and the sediments therein. Different cave environments allow the development ofvarious minerogenetic mechanisms, the most important of which are double exchange reactions, evaporation, oxidation, hydrationdehydration,sublimation, deposition from aerosols and vapors, and segregation. The cave temperature and pH/Eh strictly controlmost of them, although some are driven by microorganisms. The cave environment, due to its long-term stability, can sometimesallow for the development of huge euhedral crystals, such as those found in the Naica caves (Mexico, but the presence of extremelysmall yet complex aggregates of different minerals is far more common. Future development in the field of cave mineralogy will likelybe focused mainly on hydrothermal and sulfuric-acid caves and on the role played by micro-organisms in controlling some of the mostimportant minerogenetic processes in caves.

Pathogenic and opportunistic microorganisms in caves

Directory of Open Access Journals (Sweden)

Sanchez-Moral Sergio

2010-01-01

Full Text Available With today’s leisure tourism, the frequency of visits to many caves makes it necessary to know about possible potentially pathogenic microorganisms in caves, determine their reservoirs, and inform the public about the consequences of such visits. Our data reveal that caves could be a potential danger to visitors because of the presence of opportunistic microorganisms, whose existence and possible development in humans is currently unknown.

Diurnal Variation of Radon Concentration in the Postojna Cave

International Nuclear Information System (INIS)

Gregoric, A.; Vaupotic, J.

2011-01-01

Postojna Cave, with 20 km of galleries, is the longest known cave system and also the largest of about 20 show caves in Slovenia and one of the most visited show caves in the world. It is well known that high concentrations of radon are common in karstic caves, although quantities of uranium (238U) in limestone are rather low. The reason for this is low natural ventilation of the underground cavities. Tectonic faults constitute an additional source of radon. Variations of radon concentration in cave air arise from a balance of the emission from cave surfaces and drip waters, decay in cave air, and exchange with the outside atmosphere. Because of its elevated radon concentrations, Postojna Cave has been under permanent radon survey since 1995. The influence of meteorological conditions on the radon levels and their temporal variations depends mostly on the shape of the cave, and the number and directions of cracks, corridors and fissures connecting the cave rooms with the outside atmosphere. The driving force for air movement in horizontal caves, and thus the inflow of fresh air and release of the cave air to the atmosphere, is the temperature difference between the cave air and outdoors, which causes seasonal pattern of radon concentration in the cave with high levels in summer and low in winter. However, on a daily scale different behaviour of radon can be observed at different locations in the cave. In this paper diurnal variation of radon concentration at two locations is presented and discussed. Postojna Cave is a horizontal cave with a stable yearly temperature around 10 degrees of @C. Continuous measurements of radon concentration were carried out from 2005 to 2010 at two locations along the guided tourist trail. Radon concentration was measured with Radim 5 WP monitors (SMM Company, Prague, Czech Republic) with sampling frequency once an hour. The evaluation of five-year radon monitoring at two sites in the Postojna Cave reveals significant diurnal and

Induction melter apparatus

Science.gov (United States)

Roach, Jay A [Idaho Falls, ID; Richardson, John G [Idaho Falls, ID; Raivo, Brian D [Idaho Falls, ID; Soelberg, Nicholas R [Idaho Falls, ID

2008-06-17

Apparatus and methods of operation are provided for a cold-crucible-induction melter for vitrifying waste wherein a single induction power supply may be used to effect a selected thermal distribution by independently energizing at least two inductors. Also, a bottom drain assembly may be heated by an inductor and may include an electrically resistive heater. The bottom drain assembly may be cooled to solidify molten material passing therethrough to prevent discharge of molten material therefrom. Configurations are provided wherein the induction flux skin depth substantially corresponds with the central longitudinal axis of the crucible. Further, the drain tube may be positioned within the induction flux skin depth in relation to material within the crucible or may be substantially aligned with a direction of flow of molten material within the crucible. An improved head design including four shells forming thermal radiation shields and at least two gas-cooled plenums is also disclosed.

INTEGRATED DM 1200 MELTER TESTING OF HLW C-106/AY-102 COMPOSITION USING BUBBLERS VSL-03R3800-1 REV 0 9/15/03

Energy Technology Data Exchange (ETDEWEB)

KRUGER AA; MATLACK KS; GONG W; BARDAKCI T; D' ANGELO NA; KOT WK; PEGG IL

2011-12-29

This report documents melter and off-gas performance results obtained on the DM1200 HLW Pilot Melter during processing of simulated HLW C-106/AY-102 feed. The principal objectives of the DM1200 melter testing were to determine the achievable glass production rates for simulated HLW C-106/AY-102 feed; determine the effect of bubbling rate on production rate; characterize melter off-gas emissions; characterize the performance of the prototypical off-gas system components as well as their integrated performance; characterize the feed, glass product, and off-gas effluents; and to perform pre- and post test inspections of system components.

Integrated DM 1200 Melter Testing Of HLW C-106/AY-102 Composition Using Bubblers VSL-03R3800-1, Rev. 0, 9/15/03

International Nuclear Information System (INIS)

Kruger, A.A.; Matlack, K.S.; Kot, W.K.; Bardakci, T.; Gong, W.; D'Angelo, N.A.; Pegg, I.L.

2011-01-01

This report documents melter and off-gas performance results obtained on the DM1200 HLW Pilot Melter during processing of simulated HLW C-106/AY-102 feed. The principal objectives of the DM1200 melter testing were to determine the achievable glass production rates for simulated HLW C-106/AY-102 feed; determine the effect of bubbling rate on production rate; characterize melter off-gas emissions; characterize the performance of the prototypical off-gas system components as well as their integrated performance; characterize the feed, glass product, and off-gas effluents; and to perform pre- and post test inspections of system components.

Microbiological and environmental issues in show caves.

Science.gov (United States)

Saiz-Jimenez, Cesareo

2012-07-01

Cultural tourism expanded in the last half of the twentieth century, and the interest of visitors has come to include caves containing archaeological remains. Some show caves attracted mass tourism, and economical interests prevailed over conservation, which led to a deterioration of the subterranean environment and the rock art. The presence and the role of microorganisms in caves is a topic that is often ignored in cave management. Knowledge of the colonisation patterns, the dispersion mechanisms, and the effect on human health and, when present, over rock art paintings of these microorganisms is of the utmost importance. In this review the most recent advances in the study of microorganisms in caves are presented, together with the environmental implications of the findings.

Mechanism and Prevention of a Chock Support Failure in the Longwall Top-Coal Caving Faces: A Case Study in Datong Coalfield, China

Directory of Open Access Journals (Sweden)

Zhu Li

2018-01-01

Full Text Available Longwall chock support failures seriously restrain the safety and high-efficiency of mining of extra thick coal seams, as well as causing a great waste of coal resources. During longwall top-coal caving (LTCC, the influential effect of the properties and the movement regulation of top-coal on strata behavior cannot be ignored, since the top-coal is the medium through which the load of the overlying strata is transferred to the chock supports. Taking Datong coalfield as an example, the mechanism of a chock support failure in the LTCC face was investigated. Research findings indicated that the hard top-coal and insufficient chock support capacity were primary reasons for chock support failure accidents. On account of the field-measured results, a new method to determine support capacity was proposed, which fully took the impact of the top-coal strength into consideration. The calculation revealed that the required support capacity had exceeded the existing production maximum, at about 22,000 KN. Since it was unrealistic to simply increase chock support capacity, other approaches, according to the theoretical analysis, were proposed, such as lowering the integrity and strength of the top-coal, and upgrading its crushing effect to weaken the support load effectively during the weighting period, which reduces the likelihood of chock support accidents occurring. Based on this, hydraulic fracturing for hard top-coal and optimization of the caving process (chock supports raised up and down repeatedly by manual operation before moving forward were presented. The proposed solutions were successfully applied in LTCC-west8101 for subsequent mining and achieved substantial benefits. The above research provides valuable references and ideas for the control of strata behavior to ensure safe and highly efficient mining in extremely thick and hard coal seams with the LTCC method.

Genomic sequencing of Pleistocene cave bears

Energy Technology Data Exchange (ETDEWEB)

Noonan, James P.; Hofreiter, Michael; Smith, Doug; Priest, JamesR.; Rohland, Nadin; Rabeder, Gernot; Krause, Johannes; Detter, J. Chris; Paabo, Svante; Rubin, Edward M.

2005-04-01

Despite the information content of genomic DNA, ancient DNA studies to date have largely been limited to amplification of mitochondrial DNA due to technical hurdles such as contamination and degradation of ancient DNAs. In this study, we describe two metagenomic libraries constructed using unamplified DNA extracted from the bones of two 40,000-year-old extinct cave bears. Analysis of {approx}1 Mb of sequence from each library showed that, despite significant microbial contamination, 5.8 percent and 1.1 percent of clones in the libraries contain cave bear inserts, yielding 26,861 bp of cave bear genome sequence. Alignment of this sequence to the dog genome, the closest sequenced genome to cave bear in terms of evolutionary distance, revealed roughly the expected ratio of cave bear exons, repeats and conserved noncoding sequences. Only 0.04 percent of all clones sequenced were derived from contamination with modern human DNA. Comparison of cave bear with orthologous sequences from several modern bear species revealed the evolutionary relationship of these lineages. Using the metagenomic approach described here, we have recovered substantial quantities of mammalian genomic sequence more than twice as old as any previously reported, establishing the feasibility of ancient DNA genomic sequencing programs.

Control of high level radioactive waste-glass melters - Part 5: Modeling of complex redox effects

International Nuclear Information System (INIS)

Bickford, D.F.; Choi, A.S.

1991-01-01

Computerized thermodynamic computations are useful in predicting the sequence and products of redox reactions and in assessing process variations. The redox state of waste-glass melters is determined by balance between the reducing potential of organic compounds in the feed, and the oxidizing potential of gases above the melt, and nitrates and polyvalent elements in the waste. Semiquantitative models predicting limitations of organic content have been developed based on crucible testing. Continuous melter test results have been compared to this improved staged-thermodynamic model of redox behavior

Crystal accumulation in the Hanford Waste Treatment Plant high level waste melter: Summary of FY2016 experiements

Energy Technology Data Exchange (ETDEWEB)

Fox, K. [Savannah River Site (SRS), Aiken, SC (United States); Fowley, M. [Savannah River Site (SRS), Aiken, SC (United States); Miller, D. [Savannah River Site (SRS), Aiken, SC (United States)

2016-12-01

Five experiments were completed with the full-scale, room temperature Hanford Waste Treatment and Immobilization Plant (WTP) high-level waste (HLW) melter riser test system to observe particle flow and settling in support of a crystal tolerant approach to melter operation. A prototypic pour rate was maintained based on the volumetric flow rate. Accumulation of particles was observed at the bottom of the riser and along the bottom of the throat after each experiment. Measurements of the accumulated layer thicknesses showed that the settled particles at the bottom of the riser did not vary in thickness during pouring cycles or idle periods. Some of the settled particles at the bottom of the throat were re-suspended during subsequent pouring cycles, and settled back to approximately the same thickness after each idle period. The cause of the consistency of the accumulated layer thicknesses is not year clear, but was hypothesized to be related to particle flow back to the feed tank. Additional experiments reinforced the observation of particle flow along a considerable portion of the throat during idle periods. Limitations of the system are noted in this report and may be addressed via future modifications. Follow-on experiments will be designed to evaluate the impact of pouring rate on particle re-suspension, the influence of feed tank agitation on particle accumulation, and the effect of changes in air lance positioning on the accumulation and re-suspension of particles at the bottom of the riser. A method for sampling the accumulated particles will be developed to support particle size distribution analyses. Thicker accumulated layers will be intentionally formed via direct addition of particles to select areas of the system to better understand the ability to continue pouring and re-suspend particles. Results from the room temperature system will be correlated with observations and data from the Research Scale Melter (RSM) at Pacific Northwest National Laboratory

Rheological Studies on Pretreated Feed and Melter Feed from AW-101 and AN-107

International Nuclear Information System (INIS)

Bredt, Paul R; Swoboda, Robert G

2001-01-01

Rheological and physical properties testing were conducted on actual AN-107 and AW-101 pretreated feed samples prior to the addition of glass formers. Analyses were repeated following the addition of glass formers. The AN-107 and AW-101 pretreated feeds were tested at the target sodium values of nominally 6, 8, and 10 M. The AW-101 melter feeds were tested at these same concentrations, while the AN-107 melter feeds were tested at 5, 6, and 8 M with respect to sodium. These data on actual waste are required to validate and qualify results obtained with simulants

Microbial communities in dark oligotrophic volcanic ice cave ecosystems of Mt. Erebus, Antarctica

Directory of Open Access Journals (Sweden)

Bradley M. Tebo

2015-03-01

Full Text Available The Earth’s crust hosts a subsurface, dark, and oligotrophic biosphere that is poorly understood in terms of the energy supporting its biomass production and impact on food webs at the Earth’s surface. Dark oligotrophic volcanic ecosystems (DOVEs are good environments for investigations of life in the absence of sunlight as they are poor in organics, rich in chemical reactants and well known for chemical exchange with Earth’s surface systems. Ice caves near the summit of Mt. Erebus (Antarctica offer DOVEs in a polar alpine environment that is starved in organics and with oxygenated hydrothermal circulation in highly reducing host rock. We surveyed the microbial communities using PCR, cloning, sequencing and analysis of the small subunit (16S ribosomal and Ribulose-1,5-bisphosphate Carboxylase/Oxygenase (RubisCO genes in sediment samples from three different caves, two that are completely dark and one that receives snow-filtered sunlight seasonally. The microbial communities in all three caves are composed primarily of Bacteria and fungi; Archaea were not detected. The bacterial communities from these ice caves display low phylogenetic diversity, but with a remarkable diversity of RubisCO genes including new deeply branching Form I clades, implicating the Calvin-Benson-Bassham cycle as a pathway of CO2 fixation. The microbial communities in one of the dark caves, Warren Cave, which has a remarkably low phylogenetic diversity, were analyzed in more detail to gain a possible perspective on the energetic basis of the microbial ecosystem in the cave. Atmospheric carbon (CO2 and CO, including from volcanic emissions, likely supplies carbon and/or some of the energy requirements of chemoautotrophic microbial communities in Warren Cave and probably other Mt. Erebus ice caves. Our work casts a first glimpse at Mt. Erebus ice caves as natural laboratories for exploring carbon, energy and nutrient sources in the subsurface biosphere and the

DC Graphite Arc Melter for vitrification of low-level waste

International Nuclear Information System (INIS)

Desrosiers, A.E.; Wilver, P.J.; Wittle, J.K.

1996-01-01

The volume of mixed waste continues to increase with few options for its permanent disposal other than storage on site. This mixed waste is being generated by not only the Department of Energy at government sites but by the private sector in hospitals and at electrical utility sites. Bartlett Services, Inc. proposes to offer a service to treat these materials to both reduce the volume and stabilize the radionuclides in a vitrified material. This product will be formed in the DC Graphite Arc Melters developed by Electro-Pyrolysis, Inc. and being offered for commercial design, sale and installation by Svedala Industries, Pyro Division. The process is a high temperature procedure which pyrolytically decomposes the organic portion of the waste to form clean hydrogen and carbon monoxide and solid carbon. The inorganic portion, containing the radioactive components, melts to produce a stable glass which is resistant to environmental leaching and will remain stable until the radioactivity has decreased to a safe level. Glasses produced with surrogate materials such as cesium and cerium have been shown to pass the Product Compatibility Test (PCT). The process being proposed for this treatment utilizes a sealed melter system having the capability of melting wastes containing both metallic and inorganic materials. This process, unlike joule heated melters, is capable of operating to temperatures of 1600 degrees C or higher. Since the system is heated electrically, oxidation is not required to create the heat. Since the system is pyrolytic, relatively small quantities of gas are produced. These gases may have beneficial uses in producing chemicals or may be used as a clean fuel

Distinction between epigenic and hypogenic maze caves

Science.gov (United States)

Palmer, Arthur N.

2011-11-01

Certain caves formed by dissolution of bedrock have maze patterns composed of closed loops in which many intersecting fractures or pores have enlarged simultaneously. Their origin can be epigenic (by shallow circulation of meteoric groundwater) or hypogenic (by rising groundwater or production of deep-seated solutional aggressiveness). Epigenic mazes form by diffuse infiltration through a permeable insoluble caprock or by floodwater supplied by sinking streams. Most hypogenic caves involve deep sources of aggressiveness. Transverse hypogenic cave origin is a recently proposed concept in which groundwater of mainly meteoric origin rises across strata in the distal portions of large flow systems, to form mazes in soluble rock sandwiched between permeable but insoluble strata. The distinction between maze types is debated and is usually based on examination of diagnostic cave features and relation of caves to their regional setting. In this paper, the principles of mass transfer are applied to clarify the limits of each model, to show how cave origin is related to groundwater discharge, dissolution rate, and time. The results show that diffuse infiltration and floodwater can each form maze caves at geologically feasible rates (typically within 500 ka). Transverse hypogenic mazes in limestone, to enlarge significantly within 1 Ma, require an unusually high permeability of the non-carbonate beds (generally ≥ 10-4 cm/s), large discharge, and calcite saturation no greater than 90%, which is rare in deep diffuse flow in sedimentary rocks. Deep sources of aggressiveness are usually required. The origin of caves by transverse hypogenic flow is much more favorable in evaporite rocks than in carbonate rocks.

Simulated effects of increased groundwater withdrawals in the Cave Springs area, Hixson, Tennessee

Science.gov (United States)

Haugh, Connor J.

2014-01-01

Concern for future water supplies in Tennessee has grown in recent years as a result of increased awareness of competing needs, the impact of droughts, and the need for more water to support growing populations. The U.S. Geological Survey conducts investigations to improve the knowledge about interactions of geology, climate, humans, and ecosystems with the water cycle, which is critical to understanding and optimizing water availability. The Hixson Utility District in Hamilton County, Tennessee, uses groundwater resources in the Cave Springs area as a water supply, withdrawing water from two well fields located at Cave Springs and Walkers Corner. Historically, Hixson Utility District has withdrawn about 5 million gallons per day (Mgal/d) at the Cave Springs well field and between 2 and 3 Mgal/d at the Walkers Corner well field. To assess the capacity of the groundwater resources in the Cave Springs area to meet future demands, four different scenarios of increased groundwater withdrawals were analyzed using computer model simulations.

Oxygen enriched combustion system performance study. Phase 2: 100 percent oxygen enriched combustion in regenerative glass melters, Final report

Energy Technology Data Exchange (ETDEWEB)

Tuson, G.B.; Kobayashi, H.; Campbell, M.J.

1994-08-01

The field test project described in this report was conducted to evaluate the energy and environmental performance of 100% oxygen enriched combustion (100% OEC) in regenerative glass melters. Additional objectives were to determine other impacts of 100% OEC on melter operation and glass quality, and to verify on a commercial scale that an on-site Pressure Swing Adsorption oxygen plant can reliably supply oxygen for glass melting with low electrical power consumption. The tests constituted Phase 2 of a cooperative project between the United States Department of Energy, and Praxair, Inc. Phase 1 of the project involved market and technical feasibility assessments of oxygen enriched combustion for a range of high temperature industrial heating applications. An assessment of oxygen supply options for these applications was also performed during Phase 1, which included performance evaluation of a pilot scale 1 ton per day PSA oxygen plant. Two regenerative container glass melters were converted to 100% OEC operation and served as host sites for Phase 2. A 75 ton per day end-fired melter at Carr-Lowrey Glass Company in Baltimore, Maryland, was temporarily converted to 100% OEC in mid- 1990. A 350 tpd cross-fired melter at Gallo Glass Company in Modesto, California was rebuilt for permanent commercial operation with 100% OEC in mid-1991. Initially, both of these melters were supplied with oxygen from liquid storage. Subsequently, in late 1992, a Pressure Swing Adsorption oxygen plant was installed at Gallo to supply oxygen for 100% OEC glass melting. The particular PSA plant design used at Gallo achieves maximum efficiency by cycling the adsorbent beds between pressurized and evacuated states, and is therefore referred to as a Vacuum/Pressure Swing Adsorption (VPSA) plant.

Structural and hydrological controls on the development of a river cave in marble (Tapagem Cave - SE Brazil

Directory of Open Access Journals (Sweden)

William Sallun Filho

2015-01-01

Full Text Available Tapagem Cave (or Devil’s Cave is a river cave developed in the dolomite marble karst of the Serra do André Lopes (State of São Paulo, southeastern Brazil. Although this region is a plateau with significant variation in elevation and a humid subtropical climate, the cave is an anomalous feature in the André Lopes karst because there are few other caves. The marble, which is in a synclinal structure with subjacent phyllites, is a karst aquifer perched above the regional base level (Ribeira River and has little allogenic recharge. The cave developed on a secondary anticline on the northwest flank of the marble synform forming a blind valley, the Tapagem River sink, that is an underground tributary of Ostras River. Development of the cave is due to the entrenchment of the Ostras through-valley and the large allogenic catchment area of the sink. In plan view, the morphology of the cave can be divided into three different sectors. The first sector, known as the Tourist Sector, has extensive collapse rooms, fossil passages and a variety of speleothems of notable dimensions. The second and most extensive sector is the river passage, which is a sinuous gallery controlled by marble banding with NE-SW cleavage and NW-SE fractures. In cross-section, the passages are vadose canyons up to 70 m in height, controlled by the marble banding. Four NW-SE diabase dykes in this passage do not affect its direction in plan view. The third sector is an extensive network of passages and collapse rooms, which are interlaced in plan view and on different levels, forming a maze pattern. Initially, the Tapagem and Ostras Rivers developed on a gentle surface and flowed into the Ribeira River. With the entrenchment of the Ostras through-valley, the Tapagem River partially infiltrated via a paleosink into the upper passage of the “Erectus Room," remaining a half-blind valley. Following a series of collapses and obstructions, the River next infiltrated via the current

Urang Cave Karst Environmental Development, as Tourism Object

Directory of Open Access Journals (Sweden)

Srijono Srijono

2013-12-01

Full Text Available Karst environment become an alternative tourist destination as well as to boost local revenues. In karst environments in Grobogan District, Central Java Province, formed Urang Cave, with an interesting endokarst phenomenon. This study aims to do zoning district Urang Cave as tourist sites. The research method is using contour maps as a base map of Urang Cave karst environment geomorphological mapping. Geomorphological data processing is using ArcView GIS 3.3 program. Land use map refers to RBI, scale 1:25.000. Geomorphological analysis refers to the Ministry of Energy and Mineral Resources No. 1456.K/20/MEM/2000, and petrography. Each development zone is analyzed its geophysical environmental element, then set scoring and value summation. For comprehensive environmental element analysis, chemical analysis of rocks, and water-soil chemistry. In reference to Minister of Energy Mineral Resource decrees No. 1456/K/20/MEM/2000, Urang Cave zoning defined into 3 (three zone, as follow: the Protected Zone, Cultivation Zone 1, and Cultivation Zone 2. Protected Zone, consists of Urang Cave tunnel/hallway with a unique spheleothem in it. This zone as a cave tracking site tourism, potential to produce karst water as a decent drinking water while maintaining hardness. Cultivation Zone 1 is spreading about 200 m in distance from outer appearance of spring around the cave hallway. In this zone mining of cave sediments may be done in the inactive form caves, without changing the state of the existing major exokarst morphology. Cultivation Zone 2, an outer zone, located farthest from the tunnel/hallway Urang Cave. Utilization of this zone as a limestone mining quarry, although only on a small scale.

Measurements of radon concentrations at caves in Jeju

Energy Technology Data Exchange (ETDEWEB)

Go, S. H.; Kang, D. H.; Jung, B. J. [Cheju National University, Cheju (Korea, Republic of)

2004-07-01

Radon is a radioactive gas emitting {alpha} particles. It is chemically stable due to its inert characteristic. While its daughter products, {sup 218}Po, {sup 214}Bi, {sup 214}Pb and {sup 214}Po, attached with aerosol particles, is known to cause lung cancer. As radon is produced from uranium and thorium, it accumulates in poorly ventilative underground voids such as caves and mine. Radon concentrations at caves in Jeju were measured in this study. The measurements were made by setting three CR-39 detectors for 70 days at 2 {approx} 4 positions in Manjang, Hyupjae and Ssangyong caves. The radon levels of the caves spread 403.1 . 606.7 Bq/m{sup 3}. With these results, it is concluded that the Jeju caves have 6 times higher radon concentrations than ordinary house of 65.3 Bq/m{sup 3} and that they are higher than Seoul subway stations due to poor ventilation. While, the caves in Jeju have lower radon concentrations than limestone caves of Robin Hood. The radon concentration in the middle of Manjang cave is slightly higher than the action level in the work place of 500 Bq/m{sup 3} suggested by the ICRP. The measurement errors are estimated to be less than 5 % from its calibration factor.

Measurements of radon concentrations at caves in Jeju

International Nuclear Information System (INIS)

Go, S. H.; Kang, D. H.; Jung, B. J.

2004-01-01

Radon is a radioactive gas emitting α particles. It is chemically stable due to its inert characteristic. While its daughter products, 218 Po, 214 Bi, 214 Pb and 214 Po, attached with aerosol particles, is known to cause lung cancer. As radon is produced from uranium and thorium, it accumulates in poorly ventilative underground voids such as caves and mine. Radon concentrations at caves in Jeju were measured in this study. The measurements were made by setting three CR-39 detectors for 70 days at 2 ∼ 4 positions in Manjang, Hyupjae and Ssangyong caves. The radon levels of the caves spread 403.1 . 606.7 Bq/m 3 . With these results, it is concluded that the Jeju caves have 6 times higher radon concentrations than ordinary house of 65.3 Bq/m 3 and that they are higher than Seoul subway stations due to poor ventilation. While, the caves in Jeju have lower radon concentrations than limestone caves of Robin Hood. The radon concentration in the middle of Manjang cave is slightly higher than the action level in the work place of 500 Bq/m 3 suggested by the ICRP. The measurement errors are estimated to be less than 5 % from its calibration factor

Hypogene caves of the central Appalachian Shenandoah Valley in Virginia

Science.gov (United States)

Doctor, Daniel H.; Orndorff, Wil

2017-01-01

Several caves in the Shenandoah Valley in Virginia show evidence for early hypogenic conduit development with later-enhanced solution under partly confined phreatic conditions guided by geologic structures. Many (but not all) of these caves have been subsequently invaded by surface waters as a result of erosion and exhumation. Those not so affected are relict phreatic caves, bearing no relation to modern drainage patterns. Field and petrographic evidence shows that carbonate rocks hosting certain relict phreatic caves were dolomitized and/or silicified by early hydrothermal fluid migration in zones that served to locally enhance rock porosity, thus providing preferential pathways for later solution by groundwater flow, and making the surrounding bedrock more resistant to surficial weathering to result in caves that reside within isolated hills on the land surface. Features suggesting that deep phreatic processes dominated the development of these relict caves include (1) cave passage morphologies indicative of ascending fluids, (2) cave plans of irregular pattern, reflecting early maze or anastomosing development, (3) a general lack of cave breakdown and cave streams or cave stream deposits, and (4) calcite wall and pool coatings within isolated caves intersecting the local water table, and within unroofed caves at topographic locations elevated well above the local base level. Episodes of deep karstification were likely separated by long periods of geologic time, encompassing multiple phases of sedimentary fill and excavation within caves, and reflect a complex history of deep fluid migration that set the stage for later shallow speleogenesis that continues today.

Steam Explosions in Slurry-fed Ceramic Melters

Energy Technology Data Exchange (ETDEWEB)

Carter, J.T.

2001-03-28

This report assesses the potential and consequences of a steam explosion in Slurry Feed Ceramic Melters (SFCM). The principles that determine if an interaction is realistically probable within a SFCM are established. Also considered are the mitigating effects due to dissolved, non-condensable gas(es) and suspended solids within the slurry feed, radiation, high glass viscosity, and the existence of a cold cap. The report finds that, even if any explosion were to occur, however, it would not be large enough to compromise vessel integrity.

Bioaccumulation of eight heavy metals in cave animals from Dashui ...

African Journals Online (AJOL)

ajl2

karst caves and water systems in the caves are well developed. So, heavy metals can contaminate cave envi- ronment and affect cave animals. Karst topography is widely distributed in Guizhou province, China, accounting for 73.8% of the total land area. So, the examination of heavy metal pollution in cave soil and water ...

Measurements of radon levels inside Mexican caves

International Nuclear Information System (INIS)

Borau, J.; Gonzalez, A.; Espinosa, G.; Golzarri, J.I.

1993-01-01

Living animal species on earth have been exposed to environmental radon from the very beginning of time. The effects of radiation, combined with other natural parameters such as temperature, humidity, salt contents, etc., have most likely influenced the evaluation of different species. Thus, it is important to know and to evaluate the radon levels, among other radioactive elements present in enclosed environments such as caves, especially since those caves were also the dwellings and refuge of the predecessor of man. In this work we present radon level measurements inside some caves with vestiges of ancient inhabitats and some recently discovered natural caves, using Nuclear Track Detectors. (author)

Contextualizing Cave Maps as Geospatial Information: Case Study of Indonesia

Science.gov (United States)

Reinhart, H.

2017-12-01

Caves are the result of solution processes. Because they are happened from geochemical and tectonic activity, they can be considered as geosphere phenomena. As one of the geosphere phenomena, especially at karst landform, caves have spatial dimensions and aspects. Cave’s utilizations and developments are increasing in many sectors such as hydrology, earth science, and tourism industry. However, spatial aspects of caves are poorly concerned dues to the lack of recognition toward cave maps. Many stakeholders have not known significances and importance of cave maps in determining development of a cave. Less information can be considered as the cause. Therefore, it is strongly necessary to put cave maps into the right context in order to make stakeholders realize the significance of it. Also, cave maps will be officially regarded as tools related to policy, development, and conservation act of caves hence they will have regulation in the usages and applications. This paper aims to make the contextualization of cave maps toward legal act. The act which is used is Act Number 4 Year 2011 About Geospatial Information. The contextualization is done by scrutinizing every articles and clauses related to cave maps and seek the contextual elements from both of them. The results are that cave maps can be regarded as geospatial information and classified as thematic geospatial information. The usages of them can be regulated through the Act Number 4 Year 2011. The regulations comprised by data acquisition, database, authorities, surveyor, and the obligation of providing cave maps in planning cave’s development and the environment surrounding.

Millipedes (Diplopoda of twelve caves in Western Mecsek, Southwest Hungary

Directory of Open Access Journals (Sweden)

Angyal, D.

2013-11-01

Full Text Available Twelve caves of Western Mecsek, Southwest Hungary were examined between September 2010 and April 2013from the millipede (Diplopoda faunistical point of view. Ten species were found in eight caves, which consistedeutroglophile and troglobiont elements as well. The cave with the most diverse fauna was the Törökpince Sinkhole, while thetwo previously also investigated caves, the Abaligeti Cave and the Mánfai-kőlyuk Cave provided less species, which couldbe related to their advanced touristic and industrial utilization.

FINAL REPORT START-UP AND COMMISSIONING TESTS ON THE DURAMELTER 1200 HLW PILOT MELTER SYSTEM USING AZ-101 HLW SIMULANTS VSL-01R0100-2 REV 0 1/20/03

Energy Technology Data Exchange (ETDEWEB)

KRUGER AA; MATLACK KS; KOT WK; BRANDYS M; WILSON CN; SCHATZ TR; GONG W; PEGG IL

2011-12-29

This document provides the final report on data and results obtained from commissioning tests performed on the one-third scale DuraMelter{trademark} 1200 (DM 1200) HLW Pilot Melter system that has been installed at VSL with an integrated prototypical off-gas treatment system. That system has replaced the DM1000 system that was used for HLW throughput testing during Part BI [1]. Both melters have similar melt surface areas (1.2 m{sup 2}) but the DM1200 is prototypical of the present RPP-WTP HLW melter design whereas the DM1000 was not. These tests were performed under a corresponding RPP-WTP Test Specification and associated Test Plan. This report is a followup to the previously issued Preliminary Data Summary Report. The DM1200 system will be used for testing and confirmation of basic design, operability, flow sheet, and process control assumptions as well as for support of waste form qualification and permitting. This will include data on processing rates, off-gas treatment system performance, recycle stream compositions, as well as process operability and reliability. Consequently, this system is a key component of the overall HLW vitrification development strategy. The results presented in this report are from the initial series of short-duration tests that were conducted to support the start-up and commissioning of this system prior to conducting the main body of development tests that have been planned for this system. These tests were directed primarily at system 'debugging,' operator training, and procedure refinement. The AZ-101 waste simulant and glass composition that was used for previous testing was selected for these tests.

Final Report Start-Up And Commissioning Tests On The Duramelter 1200 HLW Pilot Melter System Using AZ-101 HLW Simulants VSL-01R0100-2, Rev. 0, 1/20/03

International Nuclear Information System (INIS)

Kruger, A.A.; Matlack, K.S.; Kot, W.K.; Brandys, M.; Wilson, C.N.; Schatz, T.R.; Gong, W.; Pegg, I.L.

2011-01-01

This document provides the final report on data and results obtained from commissioning tests performed on the one-third scale DuraMelter(trademark) 1200 (DM 1200) HLW Pilot Melter system that has been installed at VSL with an integrated prototypical off-gas treatment system. That system has replaced the DM1000 system that was used for HLW throughput testing during Part BI (1). Both melters have similar melt surface areas (1.2 m 2 ) but the DM1200 is prototypical of the present RPP-WTP HLW melter design whereas the DM1000 was not. These tests were performed under a corresponding RPP-WTP Test Specification and associated Test Plan. This report is a followup to the previously issued Preliminary Data Summary Report. The DM1200 system will be used for testing and confirmation of basic design, operability, flow sheet, and process control assumptions as well as for support of waste form qualification and permitting. This will include data on processing rates, off-gas treatment system performance, recycle stream compositions, as well as process operability and reliability. Consequently, this system is a key component of the overall HLW vitrification development strategy. The results presented in this report are from the initial series of short-duration tests that were conducted to support the start-up and commissioning of this system prior to conducting the main body of development tests that have been planned for this system. These tests were directed primarily at system 'debugging,' operator training, and procedure refinement. The AZ-101 waste simulant and glass composition that was used for previous testing was selected for these tests.

Caves as observatories for atmospheric thermal tides: an example from Ascunsă Cave, Romania

Directory of Open Access Journals (Sweden)

Virgil Drăgușin

2018-01-01

Full Text Available As part of a microclimate study at Ascunsă Cave, Romania, we used Gemini Tinytag Plus 2 data loggers to record cave air temperature variability. At one of the monitoring points we recognized the presence of semidiurnal cycles on the order of a few thousands of a degree Celsius that could be produced under the influence of the semidiurnal tidal components of the Sun (S2 or the Moon (M2. Using a Gemini Tinytag Plus 2 data logger with an external probe we measured core rock temperature and showed that it does not influence the cave air temperature on such short time scales. We thus rejected the possibility that Earth tides, mostly produced by the lunar tidal influence on the Earth’s crust, would have had a semidiurnal influence on cave air temperature. Moreover, time series analysis revealed a 12.00-hour periodicity in temperature data, specific for the S2, allowing us to assign these variations to the influence of the thermo-tidal action of the Sun. Using the Ideal Gas Law and assuming a constant volume and amount of air, we calculated that a theoretical change in atmospheric pressure of around 40 Pa was needed to produce the temperature changes we observed. This agrees with published values of atmospheric pressure changes induced by the semidiurnal solar component of the thermal tides (S2(t. We thus can assign the observed temperature changes to semidiurnal atmospheric pressure changes (S2(p induced by the thermal excitation of the Sun. Our study signals the possibility that readily available data from cave monitoring studies around the world could be used in the study of atmospheric tides. Moreover, it appears that Ascunsă Cave acts as a natural meteorological filter on a short time scale, removing the direct thermal influences of the Sun (especially night and day differences and preserving only the barometric information from the surface.

Bat ticks revisited: Ixodes ariadnae sp. nov. and allopatric genotypes of I. vespertilionis in caves of Hungary.

Science.gov (United States)

Hornok, Sándor; Kontschán, Jenő; Kováts, Dávid; Kovács, Richárd; Angyal, Dorottya; Görföl, Tamás; Polacsek, Zsolt; Kalmár, Zsuzsa; Mihalca, Andrei D

2014-04-27

In Europe two ixodid bat tick species, Ixodes vespertilionis and I. simplex were hitherto known to occur. Bat ticks were collected from cave walls and bats in Hungary. Their morphology and genotypes were compared with microscopy and conventional PCR (followed by sequencing), respectively. A year-round activity of I. vespertilionis was observed. Molecular analysis of the cytochrome oxidase subunit I (COI) gene of twenty ticks from different caves showed that the occurrence of the most common genotype was associated with the caves close to each other. A few specimens of a morphologically different tick variant were also found and their COI analysis revealed only 86-88% sequence homology with I. simplex and I. vespertilionis, respectively. The microenvironment of caves (well separated from each other) appears to support the existence of allopatric I. vespertilionis COI genotypes, most likely related to the distance between caves and to bat migration over-bridging certain caves. The name I. ariadnae sp. nov. is given to the new tick species described here for the first time.

Passive seismic tomography application for cave monitoring in DOZ underground mine PT. Freeport Indonesia

International Nuclear Information System (INIS)

Nurhandoko, Bagus Endar B.; Wely, Woen; Setiadi, Herlan; Riyanto, Erwin

2015-01-01

It is already known that tomography has a great impact for analyzing and mapping unknown objects based on inversion, travel time as well as waveform inversion. Therefore, tomography has used in wide area, not only in medical but also in petroleum as well as mining. Recently, tomography method is being applied in several mining industries. A case study of tomography imaging has been carried out in DOZ ( Deep Ore Zone ) block caving mine, Tembagapura, Papua. Many researchers are undergoing to investigate the properties of DOZ cave not only outside but also inside which is unknown. Tomography takes a part for determining this objective.The sources are natural from the seismic events that caused by mining induced seismicity and rocks deformation activity, therefore it is called as passive seismic. These microseismic travel time data are processed by Simultaneous Iterative Reconstruction Technique (SIRT). The result of the inversion can be used for DOZ cave monitoring. These information must be used for identifying weak zone inside the cave. In addition, these results of tomography can be used to determine DOZ and cave information to support mine activity in PT. Freeport Indonesia

Passive seismic tomography application for cave monitoring in DOZ underground mine PT. Freeport Indonesia

Energy Technology Data Exchange (ETDEWEB)

Nurhandoko, Bagus Endar B.; Wely, Woen; Setiadi, Herlan [WISFIR Laboratory, Earth Physics and Complex System Division, Physics Department, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung (Indonesia); Riyanto, Erwin [Geotechnical and Hydrology PT. Freeport Indonesia wonbin-ww@hotmail.com (Indonesia)

2015-04-16

It is already known that tomography has a great impact for analyzing and mapping unknown objects based on inversion, travel time as well as waveform inversion. Therefore, tomography has used in wide area, not only in medical but also in petroleum as well as mining. Recently, tomography method is being applied in several mining industries. A case study of tomography imaging has been carried out in DOZ ( Deep Ore Zone ) block caving mine, Tembagapura, Papua. Many researchers are undergoing to investigate the properties of DOZ cave not only outside but also inside which is unknown. Tomography takes a part for determining this objective.The sources are natural from the seismic events that caused by mining induced seismicity and rocks deformation activity, therefore it is called as passive seismic. These microseismic travel time data are processed by Simultaneous Iterative Reconstruction Technique (SIRT). The result of the inversion can be used for DOZ cave monitoring. These information must be used for identifying weak zone inside the cave. In addition, these results of tomography can be used to determine DOZ and cave information to support mine activity in PT. Freeport Indonesia.

Technetium Retention In WTP Law Glass With Recycle Flow-Sheet DM10 Melter Testing VSL-12R2640-1 REV 0

International Nuclear Information System (INIS)

Abramowitz, Howard; Callow, Richard A.; Joseph, Innocent

2012-01-01

Melter tests were conducted to determine the retention of technetium and other volatiles in glass while processing simulated Low Activity Waste (LAW) streams through a DM10 melter equipped with a prototypical off-gas system that concentrates and recycles fluid effiuents back to the melter feed. To support these tests, an existing DM10 system installed at Vitreous State Laboratory (VSL) was modified to add the required recycle loop. Based on the Hanford Tank Waste Treatment and Immobilization Plant (WTP) LAW off-gas system design, suitably scaled versions of the Submerged Bed Scrubber (SBS), Wet Electrostatic Precipitator (WESP), and TLP vacuum evaporator were designed, built, and installed into the DM10 system. Process modeling was used to support this design effort and to ensure that issues associated with the short half life of the 99m Tc radioisotope that was used in this work were properly addressed and that the system would be capable of meeting the test objectives. In particular, this required that the overall time constant for the system was sufficiently short that a reasonable approach to steady state could be achieved before the 99m Tc activity dropped below the analytical limits of detection. The conceptual design, detailed design, flow sheet development, process model development, Piping and Instrumentation Diagram (P and ID) development, control system design, software design and development, system fabrication, installation, procedure development, operator training, and Test Plan development for the new system were all conducted during this project. The new system was commissioned and subjected to a series of shake-down tests before embarking on the planned test program. Various system performance issues that arose during testing were addressed through a series of modifications in order to improve the performance and reliability of the system. The resulting system provided a robust and reliable platform to address the test objectives

TECHNETIUM RETENTION IN WTP LAW GLASS WITH RECYCLE FLOW-SHEET DM10 MELTER TESTING VSL-12R2640-1 REV 0

Energy Technology Data Exchange (ETDEWEB)

Abramowitz, Howard [Catholic Univ. of America, Washington, DC (United States). Vitreous State Lab.; Brandys, Marek [Catholic Univ. of America, Washington, DC (United States). Vitreous State Lab.; Cecil, Richard [Catholic Univ. of America, Washington, DC (United States). Vitreous State Lab.; D& #x27; Angelo, Nicholas [Catholic Univ. of America, Washington, DC (United States). Vitreous State Lab.; Matlack, Keith S. [Catholic Univ. of America, Washington, DC (United States). Vitreous State Lab.; Muller, Isabelle S. [Catholic Univ. of America, Washington, DC (United States). Vitreous State Lab.; Pegg, Ian L. [Energy Solutions, Federal EPC, Inc., Columbia, MD (United States); Callow, Richard A. [Energy Solutions, Federal EPC, Inc., Columbia, MD (United States); Joseph, Innocent

2012-12-11

Melter tests were conducted to determine the retention of technetium and other volatiles in glass while processing simulated Low Activity Waste (LAW) streams through a DM10 melter equipped with a prototypical off-gas system that concentrates and recycles fluid effiuents back to the melter feed. To support these tests, an existing DM10 system installed at Vitreous State Laboratory (VSL) was modified to add the required recycle loop. Based on the Hanford Tank Waste Treatment and Immobilization Plant (WTP) LAW off-gas system design, suitably scaled versions of the Submerged Bed Scrubber (SBS), Wet Electrostatic Precipitator (WESP), and TLP vacuum evaporator were designed, built, and installed into the DM10 system. Process modeling was used to support this design effort and to ensure that issues associated with the short half life of the {sup 99m}Tc radioisotope that was used in this work were properly addressed and that the system would be capable of meeting the test objectives. In particular, this required that the overall time constant for the system was sufficiently short that a reasonable approach to steady state could be achieved before the {sup 99m}Tc activity dropped below the analytical limits of detection. The conceptual design, detailed design, flow sheet development, process model development, Piping and Instrumentation Diagram (P&ID) development, control system design, software design and development, system fabrication, installation, procedure development, operator training, and Test Plan development for the new system were all conducted during this project. The new system was commissioned and subjected to a series of shake-down tests before embarking on the planned test program. Various system performance issues that arose during testing were addressed through a series of modifications in order to improve the performance and reliability of the system. The resulting system provided a robust and reliable platform to address the test objectives.

Radon Exposures in the Caves of Tenerife (Canary Islands)

International Nuclear Information System (INIS)

Pinza-Molina, C.; Alcaide, J.M.; Rodriques-Bethencourt, R.; Hernandez-Armas, J.

1999-01-01

There are more than a hundred volcanic caves and pits of various lengths on the island of Tenerife (Canary Islands, Spain). The results are presented of atmospheric radon measurements performed in three of these caves and in three pits. One of the caves selected, El Viento Cave, is nearly 20 km in length and is the longest volcanic tube in the Canarian archipelago and the second longest in the world. The measurements were performed over two distinct periods during the year using passive polycarbonate detectors. The mean radon concentrations range between 0.3 and 8 kBq.m -3 , the maximum value corresponds to a site located at 1850 m from the mouth of El Viento Cave. Possible touristic development of these caves has been taken into account in estimating the effective doses for visitors and guides (considered separately). The values obtained range from 0.3 to 100 μSv per visit for visitors. The largest effective dose would correspond to that for guides at 41 mSv.y -1 in the Viento Cave. This result would make protection against radiological hazards obligatory if the cave were to be developed as a site for tourism. (author)

Eleven bones: More fossil remains of Cave Lions and Cave Hyaenas from the North Sea area

NARCIS (Netherlands)

Bosscha Erdbrink, D.P.

1983-01-01

Six fossil Cave Lion bones and five fossil Cave Hyaena bones are described. One lion bone and one hyaena bone were dredged from the Westerschelde ( = Western Scheldt, southwestern part of the Netherlands). The other specimens were recovered from the bottom of the North Sea, in the area West and

Radon in an underground cave system in Victoria

International Nuclear Information System (INIS)

Hedt, J.C.; Boal, T.J.

1998-01-01

Radon levels in a cave system in Victoria have been measured. The variation of radon and radon progeny levels with time, position throughout the cave and season have been determined. The radiation exposure of tour guides were estimated. The data is being used to develop a radiation management plan for the tour guides. Radon concentration within a cave system was proven to be dependent to a large extent upon the rate of air exchange with outside. Cave ventilation is the single most important factor in determining if there is diurnal variation in the radon concentration

TTP SR1-6-WT-31, Milestone C.3-2 Annual Report on Clemson/INEEL Melter Work

International Nuclear Information System (INIS)

Bickford, D.F.

1999-01-01

This work is performed in collaboration with RL37WT31-C and ID77WT31-B. During the first two years of radioactive operation of the DWPF process, several areas for improvement in melter design have been identified. The continuing scope of this task is to address performance limitations and deficiencies identified by the user. SRS will design and test several configurations of the melter pour spout and associated equipment to improve consistency of performance and recommend design improvements

TTP SR1-6-WT-31, Milestone C.3-2 Annual Report on Clemson/INEEL Melter Work

Energy Technology Data Exchange (ETDEWEB)

Bickford, D.F.

1999-10-20

This work is performed in collaboration with RL37WT31-C and ID77WT31-B. During the first two years of radioactive operation of the DWPF process, several areas for improvement in melter design have been identified. The continuing scope of this task is to address performance limitations and deficiencies identified by the user. SRS will design and test several configurations of the melter pour spout and associated equipment to improve consistency of performance and recommend design improvements.

14C AMS dating Yongcheon cave

International Nuclear Information System (INIS)

Lee, J.H.; Choe, K.; Kim, J.C.; Choi, S.H.; Kang, J.; Song, S.; Song, Y.M.; Jang, J.G.

2013-01-01

The biggest island in South Korea is Jeju Island, which lies 80 km south of the mainland and has one shield volcano, Mt. Halla. The volcanic island and its lava tubes were added to the world heritage list by UNESCO in 2007. Among the many lava tubes on the island, a unique cave had been accidentally found in 2005 while some workers were replacing a telephone pole. Until the discovery, it had been completely isolated from the outside by naturally-built sand blocks. Yongcheon cave is a lime-decorated lava tube showing both the properties of a volcanic lava tube and a limestone cave. This cave, about 3 km in length, is acknowledged to be the best of this type in the world and includes a large clean-water lake, lava falls, and richly developed speleothems inside it. Even though there is archaeological evidence from well preserved pottery that ancient people entered this place, the preservation of artifacts was ensured by a geological change that made later entrance difficult. We have collected charcoal samples scattered around the cave and dated them using AMS. Ages were in the range of ca. 1570-1260 BP (A.D. 340–880) and this corresponds to the Ancient Three Kingdoms and the Unified Silla era in Korean history. The 14 C AMS measurement results presented in this paper on wood charcoal provide precise dates which will be very useful not only to clarify the nature of human activities in this cave but also to provide reference dates when comparing other dating methods.

Eogenetic caves in conglomerate: an example from Udin Boršt, Slovenia

Directory of Open Access Journals (Sweden)

Lipar Matej

2011-01-01

Full Text Available Udin Boršt is a karstified terrace of carbonate rock, which is of fluvioglacial origin, and is situated in the north-western part of Slovenia. There are 15 registered caves, which have been interpreted as caves in conglomerate, while karst of Udin Boršt itself was interpreted as conglomerate karst, shallow karst or isolated karst. In this article, caves in Udin Boršt have been interpreted as eogenetic caves. Based on porosity and bedding material, different types of caves and cave passages have developed. Four general types of eogenetic caves found in Udin Boršt are; linear stream caves, shelter caves, breakdown caves and vadose shafts.

Millipedes (Diplopoda) from caves of Portugal

DEFF Research Database (Denmark)

P. S. Reboleira, Ana Sofia; Enghoff, Henrik

2014-01-01

in caves of the mainland and the island of Madeira has provided new data about the distribution and diversity of millipedes. A review of millipedes from caves of Portugal is presented, listing fourteen species belonging to eight families, among which six species are considered troglobionts...

Seasonality of use of Za Hájovnou Cave by bears and lions

Czech Academy of Sciences Publication Activity Database

Nývltová Fišáková, Miriam

2014-01-01

Roč. 70, 1-2 (2014), s. 103-106 ISSN 0036-5343 Institutional support: RVO:68081758 Keywords : Middle Pleistocene * thin sections * seasonality * caves * the Czech Republic Subject RIV: AC - Archeology, Anthropology, Ethnology

Feasibility Study of Padarangin Cave Slogohimo Wonogiri for Eco-Tourism

Directory of Open Access Journals (Sweden)

Kuswaji Dwi Priyono

2004-01-01

Full Text Available Area of Karst of mount Sewu in countryside of Padarangin own immeasurable of potency to be developed by besides activity of mining namely the tourism activity. Cave of nature found enable to can be developed as tourism, but date not yet been known how big potency of relevant tourism with the cave.  In line with the problems, this research aim to provide basic data of potency of cave and assess elegibility of cave. Padarangin for ecotourism in Wonogiri Regeny. Method used by survey of field and interview resident. Result of research indicate that cave of Padarangin have mount of cave at height 848 m msl which relative narrow, chamber horizontal as long as 63,8 m and vertical in 32,5 m. Needed by a special equipment to enter cave with capasities 10 – 15 people once the visit/incoming, owning value of sakral trusted by local society. The cave competent to be developed as tourism object of special enthusasm with visit limited.

Remote viewing of melter interior Defense Waste Processing Facility

International Nuclear Information System (INIS)

Heckendorn, F.M. II.

1986-01-01

A remote system has been developed and demonstrated for continuous reviewing of the interior of a glass melter, which is used to vitrify highly radioactive waste. The system is currently being implemented with the Defense Waste Processing Facility (DWPF) now under construction at the Savannah River Plant (SRP). The environment in which the borescope/TV unit is implemented combines high temperature, high ionizing radiation, low light, spattering, deposition, and remote maintenance

The fungal colonisation of rock-art caves: experimental evidence.

Science.gov (United States)

Jurado, Valme; Fernandez-Cortes, Angel; Cuezva, Soledad; Laiz, Leonila; Cañaveras, Juan Carlos; Sanchez-Moral, Sergio; Saiz-Jimenez, Cesareo

2009-09-01

The conservation of rock-art paintings in European caves is a matter of increasing interest. This derives from the bacterial colonisation of Altamira Cave, Spain and the recent fungal outbreak of Lascaux Cave, France-both included in the UNESCO World Heritage List. Here, we show direct evidence of a fungal colonisation of rock tablets in a testing system exposed in Altamira Cave. After 2 months, the tablets, previously sterilised, were heavily colonised by fungi and bacteria. Most fungi isolated were labelled as entomopathogens, while the bacteria were those regularly identified in the cave. Rock colonisation was probably promoted by the dissolved organic carbon supplied with the dripping and condensation waters and favoured by the displacement of aerosols towards the interior of the cave, which contributed to the dissemination of microorganisms. The role of arthropods in the dispersal of spores may also help in understanding fungal colonisation. This study evidences the fragility of rock-art caves and demonstrates that microorganisms can easily colonise bare rocks and materials introduced into the cavity.

Local adaptation and pronounced genetic differentiation in an extremophile fish, Poecilia mexicana, inhabiting a Mexican cave with toxic hydrogen sulphide.

Science.gov (United States)

Plath, M; Hauswaldt, J S; Moll, K; Tobler, M; García De León, F J; Schlupp, I; Tiedemann, R

2007-03-01

We investigated genetic differentiation and migration patterns in a small livebearing fish, Poecilia mexicana, inhabiting a sulfidic Mexican limestone cave (Cueva del Azufre). We examined fish from three different cave chambers, the sulfidic surface creek draining the cave (El Azufre) and a nearby surface creek without the toxic hydrogen sulphide (Arroyo Cristal). Using microsatellite analysis of 10 unlinked loci, we found pronounced genetic differentiation among the three major habitats: Arroyo Cristal, El Azufre and the cave. Genetic differentiation was also found within the cave between different pools. An estimation of first-generation migrants suggests that (i) migration is unidirectional, out of the cave, and (ii) migration among different cave chambers occurs to some extent. We investigated if the pattern of genetic differentiation is also reflected in a morphological trait, eye size. Relatively large eyes were found in surface habitats, small eyes in the anterior cave chambers, and the smallest eyes were detected in the innermost cave chamber (XIII). This pattern shows some congruence with a previously proposed morphocline in eye size. However, our data do not support the proposed mechanism for this morphocline, namely that it would be maintained by migration from both directions into the middle cave chambers. This would have led to an increased variance in eye size in the middle cave chambers, which we did not find. Restricted gene flow between the cave and the surface can be explained by local adaptations to extreme environmental conditions, namely H2S and absence of light. Within the cave system, habitat properties are patchy, and genetic differentiation between cave chambers despite migration could indicate local adaptation at an even smaller scale.

Dating the Lascaux cave gour formation

International Nuclear Information System (INIS)

Genty, D.; Touma, M.; Konik, S.; Konik, S.; Valladas, H.; Hellstrom, J.; Moreau, C.; Dumoulin, J.P.; Nouet, J.; Dauphin, Y.; Weil, R.

2011-01-01

Lascaux Cave is renowned for its outstanding prehistoric paintings, strikingly well-preserved over about 18,000 yr. While stalagmites and stalactites are almost absent in the cave, there is an extensive calcite flow-stone that covered a large part of the cave until its opening for tourists during the 1950's. The deposit comprises a succession of calcite rims, or 'gours', which allowed seepage water to pond in large areas in the cave. Their possible role in preservation of the cave paintings has often been evoked, but until now this deposit has not been studied in detail. Here, we present 24 new radiocarbon accelerator mass spectrometry (AMS) and 6 uranium-thorium (U-Th) analyses from the calcite of the gours, 4 AMS 14 C dates from charcoals trapped in the calcite, and 4 AMS 14 C analyses on organic matter extracted from the calcite. Combining the calibrated 14 C ages obtained on charcoals and organic matter and U-Th ages from 14 C analyses made on the carbonate, has allowed the calculation of the dead carbon proportion (dcp) of the carbonate deposits. The latter, used with the initial atmospheric 14 C activities reconstructed with the new IntCal09 calibration data, allows high-resolution age estimation of the gour calcite samples and their growth rates. The carbonate deposit grew between 9530 and 6635 yr cal BP (for dcp = 10.7 ± 1.8%; 2 s) or between 8518 and 5489 yr cal BP (for dcp = 20.5 ± 1.9%; 2 s). This coincides with humid periods that can be related to the Atlantic period in Europe and to Sapropel 1 in the eastern Mediterranean Sea. However, geomorphological changes at the cave entrance might also have played a role in the gour development. In the 1940's, when humans entered the cave for the first time since its prehistoric occupation, the calcite gours had already been inactive for several thousand years. (authors)

Numerical simulation of formation and preservation of Ningwu ice cave, Shanxi, China

Science.gov (United States)

Yang, S.; Shi, Y.

2015-10-01

Ice caves exist in locations where annual average air temperature is higher than 0 °C. An example is Ningwu ice cave, Shanxi Province, the largest ice cave in China. In order to quantitatively investigate the mechanism of formation and preservation of the ice cave, we use the finite-element method to simulate the heat transfer process at this ice cave. There are two major control factors. First, there is the seasonal asymmetric heat transfer. Heat is transferred into the ice cave from outside very inefficiently by conduction in spring, summer and fall. In winter, thermal convection occurs that transfers heat very efficiently out of the ice cave, thus cooling it down. Secondly, ice-water phase change provides a heat barrier for heat transfer into the cave in summer. The calculation also helps to evaluate effects of global warming, tourists, colored lights, climatic conditions, etc. for sustainable development of the ice cave as a tourism resource. In some other ice caves in China, managers have installed airtight doors at these ice caves' entrances with the intention of "protecting" these caves, but this in fact prevents cooling in winter and these cave ices will entirely melt within tens of years.

Radon in the Creswell Crags Permian limestone caves

International Nuclear Information System (INIS)

Gillmore, G.K.; Phillips, P.S.; Denman, A.R.; Gilbertson, D.D.

2002-01-01

An investigation of radon levels in the caves of Creswell Crags, Derbyshire, an important Site of Special Scientific Interest (SSSI) shows that the Lower Magnesian Limestone (Permian) caves have moderate to raised radon gas levels (27-7800 Bq m -3 ) which generally increase with increasing distance into the caves from the entrance regions. This feature is partly explained in terms of cave ventilation and topography. While these levels are generally below the Action Level in the workplace (400 Bq m -3 in the UK), they are above the Action Level for domestic properties (200 Bq m -3 ). Creswell Crags has approximately 40,000 visitors per year and therefore a quantification of effective dose is important for both visitors and guides to the Robin Hood show cave. Due to short exposure times the dose received by visitors is low (0.0016 mSv/visit) and regulations concerning exposure are not contravened. Similarly, the dose received by guides is fairly low (0.4 mSv/annum) due in part to current working practice. However, the risk to researchers entering the more inaccessible areas of the cave system is higher (0.06 mSv/visit). This survey also investigated the effect of seasonal variations on recorded radon concentration. From this work summer to winter ratios of between 1.1 and 9.51 were determined for different locations within the largest cave system

Cullet Manufacture Using the Cylindrical Induction Melter

International Nuclear Information System (INIS)

Miller, D. H.

2000-01-01

The base process for vitrification of the Am/Cm solution stored in F-canyon uses 25SrABS cullet as the glass former. A small portion of the cullet used in the SRTC development work was purchased from Corning while the majority was made in the 5 inch Cylindrical Induction Melter (CIM5). Task 1.01 of TTR-NMSS/SE-006, Additional Am-Cm Process Development Studies, requested that a process for the glass former (cullet) fabrication be specified. This report provides the process details for 25SrAB cullet production thereby satisfying Task 1.01

Cave exploitation by an usual epigean species: a review on the current knowledge on fire salamander breeding in cave

Directory of Open Access Journals (Sweden)

Raoul Manenti

2017-11-01

Full Text Available The fire salamander (Salamandra salamandra is a relatively common epigean amphibian, widely distributed throughout Europe, which usually gives birth to aquatic larvae. Even if epigean streams represent the most common places in which the species breeds, in some countries caves with underground waters are also used. To improve our understanding of the habitat features allowing successful breeding of salamanders in underground sites, we combined an exhaustive review of the available literature, especially the grey one, with direct observations performed from 2008 to 2017 in several natural and artificial caves of Lombardy, Liguria and Tuscany (Italy, Ariège and Provence (France. We provide a synthesis of published and unpublished caves in which the fire salamander breeding has been observed, along with a synthesis of the investigated ecological, behavioural and morphological traits. The use of underground sites is reported in several published papers and appears to be a common phenomenon not limited to single karst areas. The absence of predators, the relative stability of the aquatic habitats and the possibility to exploit new ecological resources are environmental factors that favour the breeding of the fire salamander. Our synthesis suggests that breeding of fire salamanders in caves is not a random event, but a widespread phenomenon that may be linked to specific biogeographical factors. Further insights may be obtained by performing genetic analyses on both cave and epigean populations, and considering larger landscape scales for ecological studies as well. Gene flow between salamanders that breed in caves and in streams probably occurs, but on the other hand, assortative mating might limit it, thus allowing the conservation of local adaptations driving successful cave colonisation.

Sources of sulphate minerals in limestone cave-a possible evidence of anthropogenic activity: a case study in Črna Jama Cave (Slovenia).

Science.gov (United States)

Jarc, Simona; Miler, Miloš; Šebela, Stanka; Zupančič, Nina

2017-12-01

In the caves, the formation of cave minerals is a consequence of a variety of chemical reactions, some of them also due to human activity. There are many caves in Slovenia, but sulphate minerals are not very often reported and analysed. In this study, the presence of sulphate minerals is detected by SEM/EDS analysis of speleothems from Črna Jama, a cave near Kočevje (southern Slovenia). The cave is characterised by its dark, almost black colour on cave walls, floor and speleothems. Anthropogenic influence in the cave is still visible, including the remains of a fireplace, some inscriptions on the walls and wooden containers. The analyses of some of the black-coated speleothems reveal the presence of calcium sulphate, confirmed by XRD as gypsum. Gypsum crystals are around 50 μm in size, and they occur in thin crusts. Additionally, some rare authigenic baryte crystals a few micrometres in size are detected. The sulphates δ 34 S value in gypsum found on dark coloured speleothems is + 10.4‰ Vienna Canyon Diablo Troilite (VCDT), while the sulphate δ 34 S of the bedrock is + 8.6‰ VCDT. The more likely source of sulphate ions is thus biomass burning rather than bedrock. Also, bedrock and biomass ash are a very probable source of calcium and barium. The highly probable pyrogenous origin of sulphates draws attention to human impact on cave mineralogy.

Cryogenic Minerals in Caves of the Vizhay River (Northern Urals

Directory of Open Access Journals (Sweden)

E. P. Bazarova

2018-03-01

Full Text Available New information on the cryogenic mineral formations at the two Vizhay River caves (Northern Urals is given.   Calcite with the insignificant gypsum admixture predominates in the cryogenic material composition from both caves. In addition, the metastable phases of calcite, such as monohydrocalcite and ikaite were found. In the Saksofon Cave, calcite forms both spherulites and complanate grains. In Lednikovaya Cave, the major part of cryomaterial is presented by spherulites, which may suggests the significant supersaturation of solution. In Lednikovaya Сave, the distinct concentric structure with the growth zones denotes the cryogenic material formation in a thin water film under the partial thawing of upper part of long-term ice mound in summer. In Saksofon Cave the growth zones in crystals are poorly developed that probably caused by the seasonal glaciation in the cave and cryogenic minerals are younger than those in the Lednikovaya Cave.

MASBAL: A computer program for predicting the composition of nuclear waste glass produced by a slurry-fed ceramic melter

International Nuclear Information System (INIS)

Reimus, P.W.

1987-07-01

This report is a user's manual for the MASBAL computer program. MASBAL's objectives are to predict the composition of nuclear waste glass produced by a slurry-fed ceramic melter based on a knowledge of process conditions; to generate simulated data that can be used to estimate the uncertainty in the predicted glass composition as a function of process uncertainties; and to generate simulated data that can be used to provide a measure of the inherent variability in the glass composition as a function of the inherent variability in the feed composition. These three capabilities are important to nuclear waste glass producers because there are constraints on the range of compositions that can be processed in a ceramic melter and on the range of compositions that will be acceptable for disposal in a geologic repository. MASBAL was developed specifically to simulate the operation of the West Valley Component Test system, a commercial-scale ceramic melter system that will process high-level nuclear wastes currently stored in underground tanks at the site of the Western New York Nuclear Services Center (near West Valley, New York). The program is flexible enough, however, to simulate any slurry-fed ceramic melter system. 4 refs., 16 figs., 5 tabs

Convergence among cave catfishes: long-branch attraction and a Bayesian relative rates test.

Science.gov (United States)

Wilcox, T P; García de León, F J; Hendrickson, D A; Hillis, D M

2004-06-01

Convergence has long been of interest to evolutionary biologists. Cave organisms appear to be ideal candidates for studying convergence in morphological, physiological, and developmental traits. Here we report apparent convergence in two cave-catfishes that were described on morphological grounds as congeners: Prietella phreatophila and Prietella lundbergi. We collected mitochondrial DNA sequence data from 10 species of catfishes, representing five of the seven genera in Ictaluridae, as well as seven species from a broad range of siluriform outgroups. Analysis of the sequence data under parsimony supports a monophyletic Prietella. However, both maximum-likelihood and Bayesian analyses support polyphyly of the genus, with P. lundbergi sister to Ictalurus and P. phreatophila sister to Ameiurus. The topological difference between parsimony and the other methods appears to result from long-branch attraction between the Prietella species. Similarly, the sequence data do not support several other relationships within Ictaluridae supported by morphology. We develop a new Bayesian method for examining variation in molecular rates of evolution across a phylogeny.

A geochronological approach for cave evolution in the Cantabrian Coast (Pindal Cave, NW Spain)

Science.gov (United States)

Jimenez-Sanchez, M.; Bischoff, J.L.; Stoll, H.; Aranburu, A.

2006-01-01

Some of the oldest speleothems in the North Cantabrian Coast (Spain) are reported for the first time in this work. Pindal Cave is developed at 24 m above sea level, in a karstic massif reaching its highest surface in a marine terrace (rasa) located at 50-64 m above the present sea level. Several phases of evolution were previously recognized into the cave, including block collapse of the roof, episodic flooding and detrital sedimentation, and chemical precipitation of at least four speleothem generations over both alluvial and collapse deposits. Three of these speleothem generations have been dated by U/Th. The first generation yielded ages from 124,2 ?? 1, 5 ka BP to 73,1 ?? 0,9 ka BP, giving a minimum age for the main detritic sediments in the cave. The second one is not dated. The third generation gives an age of 3,71 ?? 0,4 ka BP (mathematically corrected to 2.7 ?? 0.5 ka BP), while for the youngest generation, with actively growing stalagmites in the cave, basal ages of 200 years BP are estimated by counting annual laminae. The data suggest a tentative maximum elevation rate close to 0, 2 mm/yr for the Cantabrian Margin in this area, although further chronological studies will be needed to check this hypothesis. ?? 2006 Gebru??der Borntraeger.

3N Cave: Longest salt cave in the world

Czech Academy of Sciences Publication Activity Database

Bruthans, J.; Filippi, Michal; Zare, M.; Asadi, N.; Vilhelm, Z.

2006-01-01

Roč. 64, č. 9 (2006), s. 10-18 ISSN 0027-7010 R&D Projects: GA AV ČR(CZ) KJB301110501 Institutional research plan: CEZ:AV0Z30130516 Keywords : salt cave * salt karst * Iran * expedition Namak Subject RIV: DB - Geology ; Mineralogy

Electrical power supply and controls for a remotely operated glass melter for nuclear waste

International Nuclear Information System (INIS)

Haideri, A.Q.

1985-01-01

An electrical power supply, controls and instruments used for a joule heated glass melter for nuclear waste are discussed. Remotely replaceable interconnection wiring assemblies for power, controls and instruments are also described

Repeated and time-correlated morphological convergence in cave-dwelling harvestmen (Opiliones, Laniatores from Montane Western North America.

Directory of Open Access Journals (Sweden)

Shahan Derkarabetian

Full Text Available BACKGROUND: Many cave-dwelling animal species display similar morphologies (troglomorphism that have evolved convergent within and among lineages under the similar selective pressures imposed by cave habitats. Here we study such ecomorphological evolution in cave-dwelling Sclerobuninae harvestmen (Opiliones from the western United States, providing general insights into morphological homoplasy, rates of morphological change, and the temporal context of cave evolution. METHODOLOGY/PRINCIPAL FINDINGS: We gathered DNA sequence data from three independent gene regions, and combined these data with Bayesian hypothesis testing, morphometrics analysis, study of penis morphology, and relaxed molecular clock analyses. Using multivariate morphometric analysis, we find that phylogenetically unrelated taxa have convergently evolved troglomorphism; alternative phylogenetic hypotheses involving less morphological convergence are not supported by Bayesian hypothesis testing. In one instance, this morphology is found in specimens from a high-elevation stony debris habitat, suggesting that troglomorphism can evolve in non-cave habitats. We discovered a strong positive relationship between troglomorphy index and relative divergence time, making it possible to predict taxon age from morphology. Most of our time estimates for the origin of highly-troglomorphic cave forms predate the Pleistocene. CONCLUSIONS/SIGNIFICANCE: While several regions in the eastern and central United States are well-known hotspots for cave evolution, few modern phylogenetic studies have addressed the evolution of cave-obligate species in the western United States. Our integrative studies reveal the recurrent evolution of troglomorphism in a perhaps unexpected geographic region, at surprisingly deep time depths, and in sometimes surprising habitats. Because some newly discovered troglomorphic populations represent undescribed species, our findings stress the need for further biological

Test plan for glass melter system technologies for vitrification of hign-sodium content low-level radioactive liquid waste, Project No. RDD-43288

International Nuclear Information System (INIS)

Higley, B.A.

1995-01-01

This document provides a test plan for the conduct of combustion fired cyclone vitrification testing by a vendor in support of the Hanford Tank Waste Remediation System, Low-Level Waste Vitrification Program. The vendor providing this test plan and conducting the work detailed within it is the Babcock ampersand Wilcox Company Alliance Research Center in Alliance, Ohio. This vendor is one of seven selected for glass melter testing

Past surface conditions and speleogenesis as inferred from cave sediments in the Great Cave of Șălitrari Mountain (SW Romania

Directory of Open Access Journals (Sweden)

Cristina M. Pușcaș

2010-08-01

Full Text Available Abstract In one of the passages in the Great Cave of Șălitrari Mountain the floor is completely covered by an alluvial deposit at least 6 m in thickness, ranging from boulders, and cobbles, to sand and clay, topped by a layer of dry bat guano. Sediment and mineral samples collected from six profiles underwent broad analyses to determine their petrological and mineralogical makeup, grain-size distribution, and paleoclimatic significance. The complicated facies alternation suggests frequent changes in the former stream’s hydrological parameters, with frequent flooding, leading to the hypothesis that the climate was somewhat wetter than today. Both the mineralogical composition of the sediment (ranging from quartz, mica, gypsum, phosphates, and calcite to garnet, zircon, titanite, olivine, serpentine, tourmaline, sphalerite, pyrite/chalcopyrite, and feldspars and the petrological composition of the larger clasts (limestone, sandstone, mudstone, granitoids, serpentinite, amphibolite, diorite, gneiss, quartzite, microconglomerate, and schist ascribe the potential source rocks to an area with contrasting lithologies, such as amphibolites, felsic and basic metaigneous, and metasedimentary rocks, mixed with a variety of detritic rocks. These rock types are not entirely comprised by the catchment area of the modern Presacina Brook, thus implying that due either to hydrological conditions, or to changes in the base level caused by river down cutting or active tectonics, the former source area was much more extensive. Based on morphological and sedimentological criteria, the cave started under pipe-full flow conditions, and further evolved during a prolonged and complex vadose phase. Evidence to support the existence of hypogene conditions is also present. Once the underground stream left the cave and most of the sediment was removed, speleothem precipitation was initiated. In this contribution we put forward evidence that argue for an extra

Differences between caves with and without bats in a Brazilian karst habitat

Directory of Open Access Journals (Sweden)

Camila G. Torquetti

2017-10-01

Full Text Available ABSTRACT. Since bats shelter in roosts during their period of diurnal inactivity, the quality and availability of roosts are important aspects of their ecology. Karst areas have great potential for the availability of day roosts, since they form caves, which serve as bat shelters. Here we characterize the caves used by bats in a preserved karst area of Southeastern Brazil. Using logistic regression analysis we identified the cave characteristics that influence bat occupation. Sixty-six caves were characterized based on measurements of internal height and width, height and width of the entrance(s of the cave, number of entrances, maximum horizontal development of cave, and internal temperature and humidity. In nineteen months we found 14 species in 32 caves. Most species were eventually recorded in multiple caves, with the exception of D. rotundus, G. soricina and A. planirostris, which were always found in the same caves. Desmodus rotundus showed maternity roost fidelity. We found no differences in microclimate between the caves that are occupied and those that are not. In other words, the microclimate of the caves studied herein can be characterized as stable over the years. The only predictor affecting the presence of bats in the study area was the cave’s maximum horizontal development: the caves that are occupied have greater horizontal development. Based on our results, we conclude that bats occupy many of the caves and that some species are more frequent in certain caves than in others, including some roosts that are used as maternity roosts. These findings indicate that these caves are important resources for the bats in the karst environment studied, and should be preserved.

3D numerical modeling of longwall mining with top-coal caving

Energy Technology Data Exchange (ETDEWEB)

Yasitli, N.E.; Unver, B. [Hacettepe University, Ankara (Turkey). Dept. of Mining Engineering

2005-02-01

Top-coal caving is the key factor affecting the efficiency of production at thick-coal seams. During production of top coal by caving behind the face not only a significant amount of coal is lost in the goaf but the coal drawn by means of caving is diluted considerably with surrounding rock. Therefore, it is not possible to carry out an efficient production operation unless caving of top coal behind the face is optimized. In this paper, results of 3D modeling of the top-coal-caving mechanism by using the finite difference code FLAC3{sup D} at the M3 longwall panel of the Omerler Underground Mine located at Tuncbilek (Turkey) are presented. According to the modeling results, maximum vertical abutment stresses were formed at a distance of 7m in front of the face. An analysis of the conditions of top coal has revealed that a 1.5 m thick layer of coal just above the shield supports is well fractured. However, a 3.5 m thick layer of coal above the fractured part is either not fractured or is fractured in the form of large blocks leading to obstruction of windows of shields during coal drawing. It is concluded that, in order to decrease dilution and increase extraction ratio and efficiency of operation, top coal should be as uniformly fractured as possible. Hence, an efficient and continuous coal flowing behind the face can be maintained. A special pre-fracture blasting strategy just sufficient enough to form cracks in the top coal is suggested by means of comparing with the results of numerical modeling.

EVALUATION OF MIXING IN THE SLURRY MIX EVAPORATOR AND MELTER FEED TANK

International Nuclear Information System (INIS)

MARINIK, ANDREW

2004-01-01

The Defense Waste Processing Facility (DWPF) vitrifies High Level radioactive Waste (HLW) currently stored in underground tanks at the Savannah River Site (SRS). The HLW currently being processed is a waste sludge composed primarily of metal hydroxides and oxides in caustic slurry. These slurries are typically characterized as Bingham Plastic fluids. The HLW undergoes a pretreatment process in the Chemical Process Cell (CPC) at DWPF. The processed HLW sludge is then transferred to the Sludge Receipt and Adjustment Tank (SRAT) where it is acidified with nitric and formic acid then evaporated to concentrate the solids. Reflux boiling is used to strip mercury from the waste and then the waste is transferred to the Slurry Mix Evaporator tank (SME). Glass formers are added as a frit slurry to the SME to prepare the waste for vitrification. This mixture is evaporated in the SME to the final concentration target. The frit slurry mixture is then transferred to the Melter Feed Tank (MFT) to be fed to the melter

Off-gas system data summary for the ninth run of the large slurry fed melter

International Nuclear Information System (INIS)

Colven, W.P.

1983-01-01

The ninth melter campaign successfully demonstrated extended operation of both melter and off-gas systems. Two critical problem areas associated with the handling of melter off-gases were resolved leading to firm definition of the DWPF Off-Gas Treatment System. These two concerns, wet scrubber decontamination efficiency and the reduction of solids deposition at the off-gas line entrance, were the primary focus of off-gas system studies during the 63-day run (LSFM-9). The Hydro-Sonic Scrubber was confirmed to be the superior candidate for wet scrubbing by outperforming all other scrubbers tested at the Equipment Test Facility (ETF). The two stage, steam-driven scrubber achieved consistent decontamination factors for cesium exceeding the required DWPF flowsheet DF of 50. As a result, the device was selected as the reference wet scrubber for the DWPF. The Off-Gas Film Cooling device continued to show promising results for reducing three accumulation of solid deposits at the entrance to the off-gas line. In addition, a rotating wire brush cleaning device provided easy and efficient removal of deposits which had accumulated. The combination of the two has adequately resolved the deposit accumulation problem and both devices have been incorporated in the DWPF design

Energy and speleogenesis: Key determinants of terrestrial species richness in caves.

Science.gov (United States)

Jiménez-Valverde, Alberto; Sendra, Alberto; Garay, Policarp; Reboleira, Ana Sofia P S

2017-12-01

The aim of this study was to unravel the relative role played by speleogenesis (i.e., the process in which a cave is formed), landscape-scale variables, and geophysical factors in the determination of species richness in caves. Biological inventories from 21 caves located in the southeastern Iberian Peninsula along with partial least square (PLS) regression analysis were used to assess the relative importance of the different explanatory variables. The caves were grouped according to the similarity in their species composition; the effect that spatial distance could have on similarity was also studied using correlation between matrices. The energy and speleogenesis of caves accounted for 44.3% of the variation in species richness. The trophic level of each cave was the most significant factor in PLS regression analysis, and epigenic caves (i.e., those formed by the action of percolating water) had significantly more species than hypogenic ones (i.e., those formed by the action of upward flows in confined aquifers). Dissimilarity among the caves was very high (multiple-site β sim  = 0.92). Two main groups of caves were revealed through the cluster analysis, one formed by the western caves and the other by the eastern ones. The significant-but low-correlation found between faunistic dissimilarity and geographical distance ( r  =   .16) disappeared once the caves were split into the two groups. The extreme beta-diversity suggests a very low connection among the caves and/or a very low dispersal capacity of the species. In the region under study, two main factors are intimately related to the richness of terrestrial subterranean species in caves: the amount of organic material (trophic level) and the formation process (genesis). This is the first time that the history of a cave genesis has been quantitatively considered to assess its importance in explaining richness patterns in comparison with other factors more widely recognized.

Cave-dwelling pholcid spiders (Araneae, Pholcidae: a review

Directory of Open Access Journals (Sweden)

Bernhard A. Huber

2018-06-01

Full Text Available Pholcidae are ubiquitous spiders in tropical and subtropical caves around the globe, yet very little is known about cave-dwelling pholcids beyond what is provided in taxonomic descriptions and faunistic papers. This paper provides a review based on a literature survey and unpublished information, while pointing out potential biases and promising future projects. A total of 473 native (i.e. non-introduced species of Pholcidae have been collected in about 1000 caves. The large majority of cave-dwelling pholcids are not troglomorphic; a list of 86 troglomorphic species is provided, including 21 eyeless species and 21 species with strongly reduced eyes. Most troglomorphic pholcids are representatives of only two genera: Anopsicus Chamberlin & Ivie, 1938 and Metagonia Simon, 1893. Mexico is by far the richest country in terms of troglomorphic pholcids, followed by several islands and mainland SE Asia. The apparent dominance of Mexico may partly be due to collectors’ and taxonomists’ biases. Most caves harbor only one pholcid species, but 91 caves harbor two and more species (up to five species. Most troglomorphic pholcids belong to two subfamilies (Modisiminae, Pholcinae, very few belong to Smeringopinae and Arteminae, none to Ninetinae. This is in agreement with the recent finding that within Pholcidae, microhabitat changes in general are concentrated in Modisiminae and Pholcinae.

Computational Fluid Dynamics Modeling of Bubbling in a Viscous Fluid for Validation of Waste Glass Melter Modeling

Energy Technology Data Exchange (ETDEWEB)

Abboud, Alexander William [Idaho National Laboratory; Guillen, Donna Post [Idaho National Laboratory

2016-01-01

At the Hanford site, radioactive waste stored in underground tanks is slated for vitrification for final disposal. A comprehensive knowledge of the glass batch melting process will be useful in optimizing the process, which could potentially reduce the cost and duration of this multi-billion dollar cleanup effort. We are developing a high-fidelity heat transfer model of a Joule-heated ceramic lined melter to improve the understanding of the complex, inter-related processes occurring with the melter. The glass conversion rates in the cold cap layer are dependent on promoting efficient heat transfer. In practice, heat transfer is augmented by inserting air bubblers into the molten glass. However, the computational simulations must be validated to provide confidence in the solutions. As part of a larger validation procedure, it is beneficial to split the physics of the melter into smaller systems to validate individually. The substitution of molten glass for a simulant liquid with similar density and viscosity at room temperature provides a way to study mixing through bubbling as an isolated effect without considering the heat transfer dynamics. The simulation results are compared to experimental data obtained by the Vitreous State Laboratory at the Catholic University of America using bubblers placed within a large acrylic tank that is similar in scale to a pilot glass waste melter. Comparisons are made for surface area of the rising air bubbles between experiments and CFD simulations for a variety of air flow rates and bubble injection depths. Also, computed bubble rise velocity is compared to a well-accepted expression for bubble terminal velocity.

{sup 14}C AMS dating Yongcheon cave

Energy Technology Data Exchange (ETDEWEB)

Lee, J.H., E-mail: jefflee@snu.ac.kr [AMS Lab., NCIRF, Seoul National University, Seoul 151-742 (Korea, Republic of); Choe, K. [AMS Lab., NCIRF, Seoul National University, Seoul 151-742 (Korea, Republic of); Kim, J.C. [Dept. of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Choi, S.H.; Kang, J.; Song, S.; Song, Y.M. [AMS Lab., NCIRF, Seoul National University, Seoul 151-742 (Korea, Republic of); Jang, J.G. [Jeju National Museum, Jeju 690-782 (Korea, Republic of)

2013-01-15

The biggest island in South Korea is Jeju Island, which lies 80 km south of the mainland and has one shield volcano, Mt. Halla. The volcanic island and its lava tubes were added to the world heritage list by UNESCO in 2007. Among the many lava tubes on the island, a unique cave had been accidentally found in 2005 while some workers were replacing a telephone pole. Until the discovery, it had been completely isolated from the outside by naturally-built sand blocks. Yongcheon cave is a lime-decorated lava tube showing both the properties of a volcanic lava tube and a limestone cave. This cave, about 3 km in length, is acknowledged to be the best of this type in the world and includes a large clean-water lake, lava falls, and richly developed speleothems inside it. Even though there is archaeological evidence from well preserved pottery that ancient people entered this place, the preservation of artifacts was ensured by a geological change that made later entrance difficult. We have collected charcoal samples scattered around the cave and dated them using AMS. Ages were in the range of ca. 1570-1260 BP (A.D. 340-880) and this corresponds to the Ancient Three Kingdoms and the Unified Silla era in Korean history. The {sup 14}C AMS measurement results presented in this paper on wood charcoal provide precise dates which will be very useful not only to clarify the nature of human activities in this cave but also to provide reference dates when comparing other dating methods.

CaveMan Enterprise version 1.0 Software Validation and Verification.

Energy Technology Data Exchange (ETDEWEB)

Hart, David

2014-10-01

The U.S. Department of Energy Strategic Petroleum Reserve stores crude oil in caverns solution-mined in salt domes along the Gulf Coast of Louisiana and Texas. The CaveMan software program has been used since the late 1990s as one tool to analyze pressure mea- surements monitored at each cavern. The purpose of this monitoring is to catch potential cavern integrity issues as soon as possible. The CaveMan software was written in Microsoft Visual Basic, and embedded in a Microsoft Excel workbook; this method of running the CaveMan software is no longer sustainable. As such, a new version called CaveMan Enter- prise has been developed. CaveMan Enterprise version 1.0 does not have any changes to the CaveMan numerical models. CaveMan Enterprise represents, instead, a change from desktop-managed work- books to an enterprise framework, moving data management into coordinated databases and porting the numerical modeling codes into the Python programming language. This document provides a report of the code validation and verification testing.

Radon concentration measurements in the desert caves of Saudi Arabia

Energy Technology Data Exchange (ETDEWEB)

Al-Mustafa, Hanan [Women College, P. O. Box 838, Dammam 31113 (Saudi Arabia); Al-Jarallah, M.I. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)]. E-mail: mibrahim@kfupm.edu.sa; Fazal-ur-Rehman [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Abu-Jarad, F. [Radiation Protection Unit, Environmental Protection Department, Saudi Aramco P.O. Box 13027, Dhahran 31311 (Saudi Arabia)

2005-11-15

Beneath the harsh deserts of Saudi Arabia lie dark chambers and complex mazes filled with strange shapes and wondrous beauty. Radon concentration measurements have been carried out in the desert caves of Al-Somman Plateau in the Eastern Province of Saudi Arabia. Passive radon dosimeters, based on alpha particle etch track detectors with an inlet filter, were used in this study. A total of 59 dosimeters were placed in five caves for a period of six months. Out of 59 dosimeters, 37 could be collected for analysis. Measurements showed significant variations in radon concentrations in caves depending upon their natural ventilation. The results of the study show that the average radon concentration in the different caves ranges from 74 up to 451Bqm{sup -3}. The average radon concentration in four of the caves was low in the range 74-114Bqm{sup -3}. However, one cave showed an average radon concentration of 451Bqm{sup -3}. Radon is not a problem for tourists in the majority of caves. However, sometimes it may imply some limitation to the working time of guides.

Radon concentration measurements in the desert caves of Saudi Arabia

International Nuclear Information System (INIS)

Al-Mustafa, Hanan; Al-Jarallah, M.I.; Fazal-ur-Rehman; Abu-Jarad, F.

2005-01-01

Beneath the harsh deserts of Saudi Arabia lie dark chambers and complex mazes filled with strange shapes and wondrous beauty. Radon concentration measurements have been carried out in the desert caves of Al-Somman Plateau in the Eastern Province of Saudi Arabia. Passive radon dosimeters, based on alpha particle etch track detectors with an inlet filter, were used in this study. A total of 59 dosimeters were placed in five caves for a period of six months. Out of 59 dosimeters, 37 could be collected for analysis. Measurements showed significant variations in radon concentrations in caves depending upon their natural ventilation. The results of the study show that the average radon concentration in the different caves ranges from 74 up to 451Bqm -3 . The average radon concentration in four of the caves was low in the range 74-114Bqm -3 . However, one cave showed an average radon concentration of 451Bqm -3 . Radon is not a problem for tourists in the majority of caves. However, sometimes it may imply some limitation to the working time of guides

Life on the edge: hydrogen sulfide and the fish communities of a Mexican cave and surrounding waters.

Science.gov (United States)

Tobler, Michael; Schlupp, Ingo; Heubel, Katja U; Riesch, Rüdiger; de León, Francisco J García; Giere, Olav; Plath, Martin

2006-12-01

Most eucaryotic organisms classified as living in an extreme habitat are invertebrates. Here we report of a fish living in a Mexican cave (Cueva del Azufre) that is rich in highly toxic H(2)S. We compared the water chemistry and fish communities of the cave and several nearby surface streams. Our study revealed high concentrations of H(2)S in the cave and its outflow (El Azufre). The concentrations of H(2)S reach more than 300 muM inside the cave, which are acutely toxic for most fishes. In both sulfidic habitats, the diversity of fishes was heavily reduced, and Poecilia mexicana was the dominant species indicating that the presence of H(2)S has an all-or-none effect, permitting only few species to survive in sulfidic habitats. Compared to habitats without H(2)S, P. mexicana from the cave and the outflow have a significantly lower body condition. Although there are microhabitats with varying concentrations of H(2)S within the cave, we could not find a higher fish density in areas with lower concentrations of H(2)S. We discuss that P. mexicana is one of the few extremophile vertebrates. Our study supports the idea that extreme habitats lead to an impoverished species diversity.

The architectural form of Qikou Cave dwellings in Chinese "Earth" culture

Science.gov (United States)

Chen, Xuanchen; Feng, Xinqun

2018-03-01

Cave building is not only a kind of architecture with unique style, but also a manifestation of Chinese traditional culture. Cave culture is an important part of Chinese traditional culture. The main purpose of this thesis which studies the architectural form of Qikou Cave, is to analyze how the cave building plays a positive role in promoting the development and application of modern resources and in cultural transmission. Based on a large amount of literature material, and taking Qikou Cave as an example, by studying the morphological characteristics of cave building, the paper takes an optimistic outlook on its future development and the sustainable development of the resources. It is expected that the cave culture can be further explored to promote the traditional Chinese culture and to drive the development of modern construction industry and resource conservation.

Supporting Calculations For Submerged Bed Scrubber Condensate Disposal Preconceptual Study

International Nuclear Information System (INIS)

Pajunen, A. J.; Tedeschi, A. R.

2012-01-01

This document provides supporting calculations for the preparation of the Submerged Bed Scrubber Condensate Disposal Preconceptual Study report. The supporting calculations include equipment sizing, Hazard Category determination, and LAW Melter Decontamination Factor Adjustments

Supporting Calculations For Submerged Bed Scrubber Condensate Disposal Preconceptual Study

Energy Technology Data Exchange (ETDEWEB)

Pajunen, A. J.; Tedeschi, A. R.

2012-09-18

This document provides supporting calculations for the preparation of the Submerged Bed Scrubber Condensate Disposal Preconceptual Study report The supporting calculations include equipment sizing, Hazard Category determination, and LAW Melter Decontamination Factor Adjustments.

Seasonal Temperature Variations controlling Cave Ventilation Processes in Cueva Larga, Puerto Rico

Science.gov (United States)

Winter, A.; Vieten, R.; Warken, S. F.; Schrӧder-Ritzrau, A.; Miller, T. E.; Scholz, D.

2016-12-01

Two years of monthly monitoring result in much better understanding of ventilation processes in caves. Cueva Larga, a tropical cave in Puerto Rico is 1440 m long with a large main passage (about 116,000 m3). Cave air pCO2 in the main passage varied seasonally, between 600 ppm in winter and 1800 ppm in summer. The seasonal variability in cave pCO2 made it possible to estimate a cave air exchange time of 36±5 days and a winter ventilation rate of 3,200±800 m3/day for the main cave passage. Calculations of virtual temperature and differences between cave and surface temperature show that the seasonal temperature cycle is the main driver of the alternation between a well-ventilated winter mode and a near-stagnant summer mode. The winter mode is characterized by a positive buoyancy contrast at night leading to maximal cave ventilation, while during summer ventilation is at a minimum. Between winter and summer, a transitional mode of partial cave ventilation is observed. On shorter time scales (diurnal to weekly), cave pCO2 is also influenced by atmospheric pressure but this variation is one order of magnitude lower than the seasonal pCO2 change. The cave morphology of Cueva Larga including its large volume, tubular shape and the obstructed cave entrance geometry are important boundary conditions for the observed ventilation patterns. Our findings emphasize that cave systems with varying morphology have to be studied individually in order to correctly describe ventilation processes.

SETTLING OF SPINEL IN A HIGH-LEVEL WASTE GLASS MELTER

International Nuclear Information System (INIS)

Pavel Hrma; Pert Schill; Lubomir Nemec

2002-01-01

High-level nuclear waste is being vitrified, i.e., converted to a durable glass that can be stored in a safe repository for hundreds of thousands of years. Waste vitrification is accomplished in reactors called melters to which the waste is charged together with glass-forming additives. The mixture is electrically heated to a temperature as high as 1150 decrees C to create a melt that becomes glass on cooling

TTP SR1-6-WT-31, Milestone C.3-2 annual report on Clemson/INEEL melter work. Revision 1

International Nuclear Information System (INIS)

Bickford, D.F.

1999-01-01

This work is performed in collaboration with RL37WT31-C and ID77WT31-B. During the first two years of radioactive operation of the DWPF process, several areas for improvement in melter design have been identified. The continuing scope of this task is to address performance limitations and deficiencies identified by the user. SRS will design and test several configurations of the melter pour spout and associated equipment to improve consistency of performance and recommend design improvements

TTP SR1-6-WT-31, Milestone C.3-2 annual report on Clemson/INEEL melter work. Revision 1

Energy Technology Data Exchange (ETDEWEB)

Bickford, D.F.

1999-12-17

This work is performed in collaboration with RL37WT31-C and ID77WT31-B. During the first two years of radioactive operation of the DWPF process, several areas for improvement in melter design have been identified. The continuing scope of this task is to address performance limitations and deficiencies identified by the user. SRS will design and test several configurations of the melter pour spout and associated equipment to improve consistency of performance and recommend design improvements.

World Register of marine Cave Species (WoRCS): a new Thematic Species Database for marine and anchialine cave biodiversity

NARCIS (Netherlands)

Gerovasileiou, Vasilis; Martínez, Alejandro; Álvarez, Fernando; Boxshall, Geoff; Humphreys, William F.; Jaume, Damià; Becking, L.E.; Muricy, Guilherme; Hengstum, van Peter J.; Dekeyzer, Stefanie; Decock, Wim; Vanhoorne, Bart; Vandepitte, Leen; Bailly, Nicolas; Iliffe, Thomas M.

2016-01-01

Scientific exploration of marine cave environments and anchialine ecosystems over recent decades has led to outstanding discoveries of novel taxa, increasing our knowledge of biodiversity. However, biological research on underwater caves has taken place only in a few areas of the world and relevant

Solar-forced diurnal regulation of cave drip rates via phreatophyte evapotranspiration

Directory of Open Access Journals (Sweden)

K. Coleborn

2016-11-01

Full Text Available We present results of a detailed study of drip rate variations at 12 drip discharge sites in Glory Hole Cave, New South Wales, Australia. Our novel time series analysis, using the wavelet synchrosqueezed transform, reveals pronounced oscillations at daily and sub-daily frequencies occurring in 8 out of the 12 monitored sites. These oscillations were not spatially or temporally homogenous, with different drip sites exhibiting such behaviour at different times of year in different parts of the cave. We test several hypotheses for the cause of the oscillations, including variations in pressure gradients between karst and cave due to cave breathing effects or atmospheric and earth tides, variations in hydraulic conductivity due to changes in viscosity of water with daily temperature oscillations, and solar-driven daily cycles of vegetative (phreatophytic transpiration. We conclude that the only hypothesis consistent with the data and hydrologic theory is that daily oscillations are caused by solar-driven pumping by phreatophytic trees which are abundant at the site. The daily oscillations are not continuous and occur sporadically in short bursts (2–14 days throughout the year due to non-linear modification of the solar signal via complex karst architecture. This is the first indirect observation leading to the hypothesis of tree water use in cave drip water. It has important implications for karst hydrology in regards to developing a new protocol to determine the relative importance of trends in drip rate, such as diurnal oscillations, and how these trends change over timescales of weeks to years. This information can also be used to infer karst architecture. This study demonstrates the importance of vegetation on recharge dynamics, information that will inform both process-based karst models and empirical estimation approaches. Our findings support a growing body of research exploring the impact of trees on speleothem paleoclimate proxies.

A radon survey performed in caves in Slovenia

International Nuclear Information System (INIS)

Jovanovic, P.

2002-01-01

A survey of radon and radon decay product concentrations in several caves in a limestone region in Slovenia was initiated in 1986. In the period from 1989 to 1998, monthly surveys were undertaken in several caves which are open to tourists or used for speleotherapy purposes. The reason for carrying out these surveys, were dose estimates obtained for the guides and medical staff working in the caves. Daily average radon gas concentration determined ranged from several 100 Bq/m 3 up to 27 kBq/m 3 . Higher values were measured in the summer period. The equilibrium factors derived ranged from 0.05 to 0.89, with the higher values being measured in the winter period in vertical caves. In horizontal caves (with two entrances located opposite one another) these values ranged between 0.55 and 0.89. Annual doses estimated on the basis of various lung models ranged from 10 mSv to 85 mSv per year and per 2000 working hours. A significant difference was observed between the doses estimated by means of dosimetric models, and those estimated on the basis of the epidemiological model presented in ICRP 65. The value for the unattached fraction indicated in ICRP 65 is about 3%, but our measurements performed in the caves yielded higher values of up to 15%, with this highest value being determined in the Postojna cave. In the coming years, we will perform measurements to obtain the values for concentrations of unattached particles of radon daughters and values for particle-size distribution in the 3 different caves with the highest occupancy times for visitors. There are no regulations in force in Slovenia affecting exposures to elevated radon and radon daughter concentrations among underground workers. The health inspectorate can impose radiation monitoring measures for the purposes of performing dose calculations for underground workers. The results from such monitoring measures will contribute to the establishment of an ordinance regulating the performance of measurements at low

Study of aerosols collected in a speleotherapeutic cave situated below Budapest, Hungary

Energy Technology Data Exchange (ETDEWEB)

Kertesz, Zs. E-mail: zsofi@moon.atomki.hu; Borbely-Kiss, I.; Hunyadi, I

1999-04-02

The Szemlohegy-cave is one of the well-known hydrothermal caves of the Rozsadomb area of Budapest, which have been used for speleotherapy of respiratory diseases for years. It is known from the periodically changing airborne radon activity concentration data, that airflow of seasonally reversed direction are formed along the cave passages and fissures due to the temperature difference between the surface and cave air. This means that an intensive interaction takes place between the cave and its environment. The pollution of nearby waters and the urban atmospheric air represents a real danger for these caves below Buda, which recently became the part of the UNESCO World Heritage. The study of cave aerosols should be very important from the point of view of either the control possibilities of the environmental impact or speleotherapy, and probably helps in getting acquainted with the cave-forming processes. In this work we applied our standard aerosol sampling method to the high-humidity environment of the caves, and we studied the elemental composition, size fractionation as well as the spatial distribution and the seasonal variation of cave aerosols. Thanks to the sensitivity of PIXE traces of anthropogenic pollution of the Budapest air are shown in the Szemlohegy-cave. Measured elemental concentrations remained less than one-tenth the air quality standard valid for the increasingly protected areas.

Study of aerosols collected in a speleotherapeutic cave situated below Budapest, Hungary

International Nuclear Information System (INIS)

Kertesz, Zs.; Borbely-Kiss, I.; Hunyadi, I.

1999-01-01

The Szemlohegy-cave is one of the well-known hydrothermal caves of the Rozsadomb area of Budapest, which have been used for speleotherapy of respiratory diseases for years. It is known from the periodically changing airborne radon activity concentration data, that airflow of seasonally reversed direction are formed along the cave passages and fissures due to the temperature difference between the surface and cave air. This means that an intensive interaction takes place between the cave and its environment. The pollution of nearby waters and the urban atmospheric air represents a real danger for these caves below Buda, which recently became the part of the UNESCO World Heritage. The study of cave aerosols should be very important from the point of view of either the control possibilities of the environmental impact or speleotherapy, and probably helps in getting acquainted with the cave-forming processes. In this work we applied our standard aerosol sampling method to the high-humidity environment of the caves, and we studied the elemental composition, size fractionation as well as the spatial distribution and the seasonal variation of cave aerosols. Thanks to the sensitivity of PIXE traces of anthropogenic pollution of the Budapest air are shown in the Szemlohegy-cave. Measured elemental concentrations remained less than one-tenth the air quality standard valid for the increasingly protected areas

Chemical deposits in volcanic caves of Argentina

Directory of Open Access Journals (Sweden)

Carlos Benedetto

1998-01-01

Full Text Available During the last Conference of the FEALC (Speleological Federation of Latin America and Caribbean Islands which was held in the town of Malargue, Mendoza, in February 1997, two volcanic caves not far from that town were visited and sampled for cave mineral studies. The first cave (Cueva del Tigre opens close to the Llancanelo lake, some 40 kms far from Malargue and it is a classical lava tube. Part of the walls and of the fallen lava blocks are covered by white translucent fibres and grains. The second visited cave is a small tectonic cavity opened on a lava bed some 100 km southward of Malargue. The cave “El Abrigo de el Manzano” is long no more than 10-12 meters with an average width of 3 meters and it hosts several bird nests, the larger of which is characterized by the presence of a relatively thick pale yellow, pale pink flowstone. Small broken or fallen samples of the secondary chemical deposits of both these caves have been collected in order to detect their mineralogical composition. In the present paper the results of the detailed mineralogical analyses carried out on the sampled material are shortly reported. In the Cueva del Tigre lava tube the main detected minerals are Sylvite, Thenardite, Bloedite and Kieserite, all related to the peculiar dry climate of that area. The flowstone of “El Abrigo de el Manzano” consists of a rather complex admixture of several minerals, the large majority of which are phosphates but also sulfates and silicates, not all yet identified. The origin of all these minerals is related to the interaction between bird guano and volcanic rock.

Cave dwellings in the Mediterranean basin

Directory of Open Access Journals (Sweden)

Viedma Urdiales Eugenia María

2011-01-01

Full Text Available The construction and use of subterranean caves for different functions has been relatively commonplace throughout history in different regions around the world, especially in the Mediterranean basin. Some of them are still standing at the beginning of the 21st century, and are a good example of adaptation to the geographic environment, and a part of the historical heritage. Following a short overview of the different Mediterranean countries, this work pays special attention to the present use of caves as dwelling spaces in Italy, and particularly in Spain where the caves are currently in an interesting process of renovation to meet the needs of the present population. This process is helping to boost the local economy, and it is funded by both private and public sources in several towns in Andalusia (Spain.

Evolution and adaptation of marine annelids in interstitial and cave habitats

DEFF Research Database (Denmark)

Martinez Garcia, Alejandro

relatives in cave subterranean ecological refugia. Active colonization and ecological speciation to particular cave niches has been alternatively suggested, but the evaluation of that scenario is obscured by the dominance of crustaceans in anchialine habitats, ecologically similar out and inside caves....... The main goal of this thesis is to explore the evolutionary processes behind colonization and adaptation to submarine cave ecosystems in the Atlantic Ocean using annelids as a model, mainly when they involved ancestrally interstitial forms. In order to do that, we studied selected lineages of annelids...... with cave and interstitial representatives, mainly the families Protodrilidae, Nerillidae, Saccocirridae and Scalibregmatidae. The studies combined the characterization of ancestral and cave habitats, with morphological investigations and phylogenetic analyses founded on extensive taxon coverage...

Stratigraphy, U-Th chronology, and paleoenvironments at Gladysvale Cave: insights into the climatic control of South African hominin-bearing cave deposits.

Science.gov (United States)

Pickering, Robyn; Hancox, Phillip J; Lee-Thorp, Julia A; Grün, Rainer; Mortimer, Graham E; McCulloch, Malcolm; Berger, Lee R

2007-11-01

Gladysvale Cave is one of the few Plio-Pleistocene hominin-bearing cave sites in South Africa that contains a well-stratified cave fill with clastic sediments interspersed with flowstones. The clastic sediments can be divided into units based on the presence of intercalated flowstones, forming flowstone bounded units (FBU). Ten MC-ICP-MS uranium-series dates on several flowstone horizons in the Gladysvale Internal Deposit fan indicate deposition from the late mid-Pleistocene ( approximately 570 ka) to Holocene ( approximately 7 ka) during limited periods of higher effective moisture. Clastic sedimentation occurred during the interceding, presumably more arid, periods. This sequence is not consistent with earlier models for South African caves that simply assumed interglacial sedimentation and glacial erosion. (13)C/(12)C data suggest that flowstone tended to form during periods with higher proportions of C(3) plants in the local vegetation, while clastic sediments reflect higher proportions of C(4) grasses, although this is not always the case. We argue that flowstones are precipitated during periods of higher effective precipitation and restricted cave entrances, while clastic sediments accumulated during periods with more open vegetation. The sedimentary fill of the fossiliferous deposits are, therefore, highly episodic in nature, with large periods of time unlikely to be represented. This has serious implications for the other hominin-bearing caves close by, as these deposits are likely to be similarly episodic. This is especially pertinent when addressing extinction events and reconstructions of paleoenvironments, as large periods of time may be unrecorded. The Gladysvale Cave fill sediments may serve as a climatically forced chronostratigraphic model for these less well-stratified and well-dated Plio-Pleistocene sites.

The CAVE (TM) automatic virtual environment: Characteristics and applications

Science.gov (United States)

Kenyon, Robert V.

1995-01-01

Virtual reality may best be defined as the wide-field presentation of computer-generated, multi-sensory information that tracks a user in real time. In addition to the more well-known modes of virtual reality -- head-mounted displays and boom-mounted displays -- the Electronic Visualization Laboratory at the University of Illinois at Chicago recently introduced a third mode: a room constructed from large screens on which the graphics are projected on to three walls and the floor. The CAVE is a multi-person, room sized, high resolution, 3D video and audio environment. Graphics are rear projected in stereo onto three walls and the floor, and viewed with stereo glasses. As a viewer wearing a location sensor moves within its display boundaries, the correct perspective and stereo projections of the environment are updated, and the image moves with and surrounds the viewer. The other viewers in the CAVE are like passengers in a bus, along for the ride. 'CAVE,' the name selected for the virtual reality theater, is both a recursive acronym (Cave Automatic Virtual Environment) and a reference to 'The Simile of the Cave' found in Plato's 'Republic,' in which the philosopher explores the ideas of perception, reality, and illusion. Plato used the analogy of a person facing the back of a cave alive with shadows that are his/her only basis for ideas of what real objects are. Rather than having evolved from video games or flight simulation, the CAVE has its motivation rooted in scientific visualization and the SIGGRAPH 92 Showcase effort. The CAVE was designed to be a useful tool for scientific visualization. The Showcase event was an experiment; the Showcase chair and committee advocated an environment for computational scientists to interactively present their research at a major professional conference in a one-to-many format on high-end workstations attached to large projection screens. The CAVE was developed as a 'virtual reality theater' with scientific content and

Assessing the origin of unusual organic formations in lava caves from Canary Islands (Spain)

Science.gov (United States)

Miller, Ana Z.; de la Rosa, Jose M.; Garcia-Sanchez, Angela M.; Pereira, Manuel F. C.; Jurado, Valme; Fernández, Octavio; Knicker, Heike; Saiz-Jimenez, Cesareo

2016-04-01

-over-even in the series of n-alkanes observed for the topsoil and black deposits has been recognized as an indication of fire. The 13C NMR spectrum of the black deposits showed a mixture of alkyl and O-alkyl compounds, carboxylic compounds and polysaccharides. Stable isotope analysis of δ 13C performed on the cave black deposits, topsoil and vegetation confirmed that the source of the organic fraction of the sample is a combination of partially charred vegetation (mainly Erica) and organic compounds from the andic soil over the cave. Therefore, these black deposits are the result of an input of plant organic matter and charred vegetation into the cave from rock fractures, which may constitute an important source of energy for cave organisms. Acknowledgments: AZM and JMR acknowledge the support from the Marie Curie Fellowships within the 7th European Community Framework Programme (Grants PIEF-GA-2012-328689-DECAVE and PCIG12-GA-2012-333784-Biocharisma respectively). The authors acknowledge the Spanish Ministry of Economy and Competitiveness (project CGL2013-41674-P) and FEDER funds for financial support.

Microwhip scorpions (Palpigradi) feed on heterotrophic cyanobacteria in Slovak caves - a curiosity among Arachnida

Czech Academy of Sciences Publication Activity Database

Smrž, J.; Kováč, L.; Mikeš, J.; Lukešová, Alena

2013-01-01

Roč. 8, č. 10 (2013), e75989 E-ISSN 1932-6203 Institutional support: RVO:60077344 Keywords : microwhip scorpions * heterotrophic cyanobacteria * Slovak caves Subject RIV: EG - Zoology Impact factor: 3.534, year: 2013

Determination of heat conductivity and thermal diffusivity of waste glass melter feed: Extension to high temperatures

International Nuclear Information System (INIS)

Rice, Jarrett A.; Pokorny, Richard; Schweiger, Michael J.; Hrma, Pavel R.

2014-01-01

The heat conductivity (λ) and the thermal diffusivity (a) of reacting glass batch, or melter feed, control the heat flux into and within the cold cap, a layer of reacting material floating on the pool of molten glass in an all-electric continuous waste glass melter. After previously estimating λ of melter feed at temperatures up to 680 deg C, we focus in this work on the λ(T) function at T > 680 deg C, at which the feed material becomes foamy. We used a customized experimental setup consisting of a large cylindrical crucible with an assembly of thermocouples, which monitored the evolution of the temperature field while the crucible with feed was heated at a constant rate from room temperature up to 1100°C. Approximating measured temperature profiles by polynomial functions, we used the heat transfer equation to estimate the λ(T) approximation function, which we subsequently optimized using the finite-volume method combined with least-squares analysis. The heat conductivity increased as the temperature increased until the feed began to expand into foam, at which point the conductivity dropped. It began to increase again as the foam turned into a bubble-free glass melt. We discuss the implications of this behavior for the mathematical modeling of the cold cap

Census of biodiversity in marine caves of the eastern Mediterranean Sea

Directory of Open Access Journals (Sweden)

V. GEROVASILEIOU

2015-03-01

Full Text Available Scientific information on the biodiversity of marine caves in the eastern Mediterranean is limited, especially when considering the extensively studied caves of the north-western and central Mediterranean. Aiming to enhance current knowledge regarding cave communities, this study represents a first assessment of the marine cave biota of the eastern Mediterranean, as this has been defined by the European Union’s Marine Strategy Framework Directive (MSFD. Information retrieved from an extensive overview of relevant scientific documents was combined with original data recorded from 23 marine caves of the north-eastern Mediterranean. Our results report a total of 520 taxa recorded in eastern Mediterranean marine caves to date, the majority of which are sponges, polychaetes, rhodophytes, bivalves, fishes, and gastropods. These include several protected, endemic, and alien species. However, not all taxonomic groups have been equally studied among different areas and future studies are expected to raise the number of endemic and alien species. The overall observed trend is that the reported species number is generally related to sampling effort and scientific expertise. The most well-studied marine cave communities of the eastern Mediterranean are those of the Aegean Sea (especially its northern sector, which presented the highest number of species, followed by those of the Levantine. Furthermore, our research in Aegean caves revealed numerous new records for the marine cave fauna of the eastern basin, while several species are reported for the first time in the marine cave habitat. The critical need for further scientific research, monitoring, and conservation of this unique ecosystem was highlighted by (i the presence of certain species endemic to the eastern Mediterranean coupled with a high proportion of alien species, especially in the Levantine, and (ii the marine cave habitat availability in isolated insular areas of the eastern Mediterranean.

High-Level Waste Melter Study Report

Energy Technology Data Exchange (ETDEWEB)

Perez, Joseph M.; Bickford, Dennis F.; Day, Delbert E.; Kim, Dong-Sang; Lambert, Steven L.; Marra, Sharon L.; Peeler, David K.; Strachan, Denis M.; Triplett, Mark B.; Vienna, John D.; Wittman, Richard S.

2001-07-13

At the Hanford Site in Richland, Washington, the path to site cleanup involves vitrification of the majority of the wastes that currently reside in large underground tanks. A Joule-heated glass melter is the equipment of choice for vitrifying the high-level fraction of these wastes. Even though this technology has general national and international acceptance, opportunities may exist to improve or change the technology to reduce the enormous cost of accomplishing the mission of site cleanup. Consequently, the U.S. Department of Energy requested the staff of the Tanks Focus Area to review immobilization technologies, waste forms, and modifications to requirements for solidification of the high-level waste fraction at Hanford to determine what aspects could affect cost reductions with reasonable long-term risk. The results of this study are summarized in this report.

Hollow volcanic tumulus caves of Kilauea Caldera, Hawaii County, Hawaii

Directory of Open Access Journals (Sweden)

William R. Halliday

1998-01-01

Full Text Available In addition to lava tube caves with commonly noted features, sizable subcrustal spaces of several types exist on the floor of Kilauea Caldera. Most of these are formed by drainage of partially stabilized volcanic structures enlarged or formed by injection of very fluid lava beneath a plastic crust. Most conspicuous are hollow tumuli, possibly first described by Walker in 1991. Walker mapped and described the outer chamber of Tumulus E-I Cave. Further exploration has revealed that it has a hyperthermic inner room beneath an adjoining tumulus with no connection evident on the surface. Two lengthy, sinuous hollow tumuli also are present in this part of the caldera. These findings support Walkers conclusions that hollow tumuli provide valuable insights into tumulus-forming mechanisms, and provide information about the processes of emplacement of pahoehoe sheet flows.

Radon in New Zealand tourist caves

International Nuclear Information System (INIS)

Lyons, R.G.; Solomon, S.B.; Langroo, R.

1998-01-01

Seasonal average radon concentrations in 112 sites in 22 NZ tourist caves have been measured using track etch detectors over an annual cycle. Values ranged from -3 to nearly 10,000 Bq m -3 . Seasonal variation was also very marked with factors of over 50 for the same site in different seasons being recorded. Thirty six percent of the sites exceeded the ICRP guideline of 1000 Bq m -3 at which action to reduce exposure is recommended. Caves are fragile ecological and chemical systems, therefore, may be seriously adversely affected by standard techniques to reduce radon concentrations. They are also complex physical systems, and an understanding of the principles and parameters governing cave aerodynamics is essential when considering options to reduce exposure. This paper discusses possible causes for variations in radon concentrations observed in this study and the implications for viable actions

Improvement of melter off-gas design for commercial HALW vitrification facility

Energy Technology Data Exchange (ETDEWEB)

Ohno, A.; Kitamura, M.; Yamanaka, T. [Ishikawajima-Harima Heavy Industries Co., Ltd., Yokohama (Japan); Yoshioka, M.; Endo, N.; Asano, N. [Japan Nuclear Cycle Development Institute, Ibaraki (Japan)

2001-07-01

The Japan commercial reprocessing plant is now under construction, and it will commence the operation in 2005. The High Active Liquid Waste (HALW) generated at the plant is treated into glass product at the vitrification facility using the Liquid Fed Joule-Heated Ceramic Melter (LFCM). The characteristic of the LFCM is that the HALW is fed directly onto the molten glass surface with the glass forming material. This process was developed by the Japan Nuclear Cycle Development Institute (JNC). The JNC process was first applied to the Tokai Vitrification Facility (TVF), which is a pilot scale plant having about 1/6 capacity of the commercial facility. The TVF has been in operation since 1995. During the operation, the rapid increase of the differential pressure between the melter plenum and the dust scrubber was observed. This phenomenon is harmful to the long-term continuous operation of TVF. And, it is also anticipated that the same phenomenon will occur in commercial vitrification facility. In order to solve this problem, the countermeasures were studied and developed. Through the study on the deposit growing mechanism, it was probable that the rapid increased differential pressure was attributed to the condensation of meta-boric acid at the outlet of the air-film cooler slits. And, the heating and the humidification of purge air were judged to be effective as the countermeasures to suppress the condensation. On the other hand, the water injection into melter off-gas pipe was found to be very effective to reduce the differential pressure as the results of the various tests. The deposit adhered on the inner surface of the off-gas pipe was almost washed out. And, it was also demonstrated that the system was superior to other systems by virtue of its simplicity and stability. In order to apply the system to the commercial scale plant, the scale-up tests were conducted at JNC mock-up facility using the acrylic model. (author)

Improvement of melter off-gas design for commercial HALW vitrification facility

International Nuclear Information System (INIS)

Ohno, A.; Kitamura, M.; Yamanaka, T.; Yoshioka, M.; Endo, N.; Asano, N.

2001-01-01

The Japan commercial reprocessing plant is now under construction, and it will commence the operation in 2005. The High Active Liquid Waste (HALW) generated at the plant is treated into glass product at the vitrification facility using the Liquid Fed Joule-Heated Ceramic Melter (LFCM). The characteristic of the LFCM is that the HALW is fed directly onto the molten glass surface with the glass forming material. This process was developed by the Japan Nuclear Cycle Development Institute (JNC). The JNC process was first applied to the Tokai Vitrification Facility (TVF), which is a pilot scale plant having about 1/6 capacity of the commercial facility. The TVF has been in operation since 1995. During the operation, the rapid increase of the differential pressure between the melter plenum and the dust scrubber was observed. This phenomenon is harmful to the long-term continuous operation of TVF. And, it is also anticipated that the same phenomenon will occur in commercial vitrification facility. In order to solve this problem, the countermeasures were studied and developed. Through the study on the deposit growing mechanism, it was probable that the rapid increased differential pressure was attributed to the condensation of meta-boric acid at the outlet of the air-film cooler slits. And, the heating and the humidification of purge air were judged to be effective as the countermeasures to suppress the condensation. On the other hand, the water injection into melter off-gas pipe was found to be very effective to reduce the differential pressure as the results of the various tests. The deposit adhered on the inner surface of the off-gas pipe was almost washed out. And, it was also demonstrated that the system was superior to other systems by virtue of its simplicity and stability. In order to apply the system to the commercial scale plant, the scale-up tests were conducted at JNC mock-up facility using the acrylic model. (author)

Palygorskite from cave sediments: case study from Wadi Haqil, United Arab Emirates

Czech Academy of Sciences Publication Activity Database

Zupan Hajna, N.; Skála, Roman; Al-Farraj, A.; Šťastný, Martin; Bosák, Pavel

2016-01-01

Roč. 9, č. 17 (2016), č. článku 689. ISSN 1866-7511 Institutional support: RVO:67985831 Keywords : palygorskite * gypsum * cave sediments * X-ray powder diffraction * scanning electron microscopy * Ras Al-Khaimah Emirate Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.955, year: 2016

FINAL REPORT REGULATORY OFF GAS EMISSIONS TESTING ON THE DM1200 MELTER SYSTEM USING HLW AND LAW SIMULANTS VSL-05R5830-1 REV 0 10/31/05

Energy Technology Data Exchange (ETDEWEB)

KRUGER AA; MATLACK KS; GONG W; BARDAKCI T; D' ANGELO NA; BRANDYS M; KOT WK; PEGG IL

2011-12-29

system was reconfigured to enable testing of the baseline HLW or LAW off-gas trains to perform off-gas emissions testing with both LAW and HLW simulants in the present work. During 2002 and 2003, many of these off-gas components were tested individually and in an integrated manner with the DM1200 Pilot Melter. Data from these tests are being used to support engineering design confirmation and to provide data to support air permitting activities. In fiscal year 2004, the WTP Project was directed by the Office of River Protection (ORP) to comply with Environmental Protection Agency (EPA) Maximum Achievable Control Technology (MACT) requirements for organics. This requires that the combined melter and off-gas system have destruction and removal efficiency (DRE) of >99.99% for principal organic dangerous constituents (PODCs). In order to provide confidence that the melter and off-gas system are able to achieve the required DRE, testing has been directed with both LAW and HLW feeds. The tests included both 'normal' and 'challenge' WTP melter conditions in order to obtain data for the potential range of operating conditions for the WTP melters and off-gas components. The WTP Project, Washington State Department of Ecology, and ORP have agreed that naphthalene will be used for testing to represent semi-volatile organics and allyl alcohol will be used to represent volatile organics. Testing was also performed to determine emissions of halides, metals, products of incomplete combustion (PICs), dioxins, furans, coplanar PCBs, total hydrocarbons, and COX and NOX, as well as the particle size distribution (PSD) of particulate matter discharged at the end of the off-gas train. A description of the melter test requirements and analytical methods used is provided in the Test Plan for this work. Test Exceptions were subsequently issued which changed the TCO catalyst, added total organic emissions (TOE) to exhaust sampling schedule, and allowing modification of the

Radon measurements using track detector in Wadi Sannur cave

International Nuclear Information System (INIS)

Shahin, F.; Eissa, M.F.; Mostafa, R.M.

2008-01-01

The most important contributors to the committed effective dose received by population due to natural sources are the short-lived decay products of radon ( 222 Rn). In natural voids, such as caves, most radon will enter the system from diffusion across the rock-air interface. It is well known that factors such as air pressure and temperature control the distribution of radon. The radon concentration measurements in the Wadi Sannur cave in Beni-Suef governorate in the period from 14 th of July 2005 to 17 th of October 2005. The average radon concentrations in the right, left and whole first cave are 916.12 ± 179.09, 819.63 ± 54.72 and 873.90± 147.11 Bq m -3 respectively. The measurements were performed using track etch detector of type Cr-39. After exposure, all detectors were etched chemically in 6.25 M NaOH solution at 70 C degrees for 6 h. The tracks were counted with an optical microscope magnifying 400 times. The average temperature inside the first cave during the period of measurements is 25-26 C degrees. The annual effective doses for the workers and visitors in the cave have been calculated. The average radon concentration in the Wadi Sannur cave, was 873.90 ± 147.11 Bq m -3 . The annual effective doses for worker and visitor in the cave were 1.33 ± 0.24 and 0.041 ± 0.007 mSv respectively. The doses are within the international recommended dose of 1.15 mSv. (author)

Decommissioning of fuel PIE caves at Berkeley Nuclear Laboratories

International Nuclear Information System (INIS)

Brant, A.W.

1990-01-01

This paper describes the first major contract awarded to private industry to carry out decommissioning of a facility with significant radiation levels. The work required operatives to work in pressurised suits, entry times were significantly affected by sources of radiation in the Caves, being as low as thirty minutes per day initially. The Caves at Berkeley Nuclear Laboratories carry out post irradiation examination of fuel elements support units and reactor core components from CEGB power stations. The decommissioning work is part of an overall refurbishment of the facility to allow the receipt of AGR Fuel Stringer Component direct from power stations. The paper describes the decommissioning and decontamination of the facility from the remote removal and clean up work carried out by the client to the hands-on work. It includes reference to entry times, work patterns, interfaces with the client and the operations of the laboratory. Details of a specially adapted size reduction method are given. (Author)

Exposure of tour guides to Radon at the Cango caves

International Nuclear Information System (INIS)

Pule, O.J.; Lindsay, R.

2008-01-01

Full text: A study was commissioned by the National Nuclear Regulator of South Africa to investigate the radon levels in the Cango caves and the associated radiological exposure to tour guides. The Cango caves are about 1.3 km in length and are visited by about 300000 tourists per annum due to their natural beauty. This study followed an earlier investigation by the Department of Health which indicated levels in excess of 1000 Bqm -3 which could lead to excess exposure of the cave tour guides. Radon in the various cave chambers and radon exposure of tour guides was measured using RAD-7 continuous radon monitor, electrets ion chambers and personnel monitoring electrets respectively. The measurements in the cave were done during summer and winter seasons to determine any variations between the seasons. The occupancy time for individual guides and equilibrium factor were also investigated. The radon concentration in the cave range from 1000 Bqm -3 to more than 2000 Bqm -3 with equilibrium factor of approximately 0.4, and the variation between winter and summer measurements are insignificant. The radon exposure levels to tour guides differ due to various time periods they spent in the caves. The average dose to tour guides due to radon is 7 mSv -a and the highest exposure is about 10 mSv -a . The exposure to tourists is found to be insignificant due to time they spent in the cave. The regulatory authority is currently investigating what action is necessary to protect the tour guides. (author)

The WP-CAVE concept for an underground high-level nuclear waste repository

International Nuclear Information System (INIS)

Pettersson, G.

1984-02-01

A central, nearly spherical cave, of diameter 40 m is excavated in rock and the waste fuel is placed in it. The fuel canisters are placed in cylindrical holes in large concrete balls which are stored at the bottom of a central stack in the cave. Other empty balls fill the rest of the cave. By natural convection, the heat is evenly distributed in the cave and the surrounding central rock body. A clay barrier, which completely surrounds the rock body, prevents ground water circulation for a very long time and protects the cave against tectonic movements. The cave can store approx. 350 tons of fuel after the 10 years of intermediate storage

Methods of Off-Gas Flammability Control for DWPF Melter Off-Gas System at Savannah River Site

International Nuclear Information System (INIS)

Choi, A.S.; Iverson, D.C.

1996-01-01

Several key operating variables affecting off-gas flammability in a slurry-fed radioactive waste glass melter are discussed, and the methods used to prevent potential off-gas flammability are presented. Two models have played a central role in developing such methods. The first model attempts to describe the chemical events occurring during the calcining and melting steps using a multistage thermodynamic equilibrium approach, and it calculates the compositions of glass and calcine gases. Volatile feed components and calcine gases are fed to the second model which then predicts the process dynamics of the entire melter off-gas system including off-gas flammability under both steady state and various transient operating conditions. Results of recent simulation runs are also compared with available data

Forensic Fluid Dynamics and the Indian Spring (1991) cave collapse problem

Science.gov (United States)

Nof, D.

2013-05-01

The collapse of the Indian spring cave (Florida) in 1991 was unique because it occurred while cave divers were in the cave. For the most part, the submerged cave is large enough to accommodate a passing truck so the cave divers were not in touch with its walls and it is hard to imagine why would it naturally collapse just when the divers were in it. Recently, Nof and Paldor (2010) resolved this apparent paradox by suggesting that resonance in the air pockets in the cavern, created by breathing (open circuit) divers, may have contributed to the collapse. In this scenario, divers present in the cavern during the dive may have (unknowingly) caused the collapse through the pressurized air/gas that they release with each breath. When the breathing period of the diver(s) matches the natural oscillations period of the "cave oscillator", the ensuing resonance causes the air pressure in the pockets to increase uncontrollably. Here, we place the above theory on a more solid ground. To do so, we first extended the resonance theory from our original two-pockets, symmetrical U-tube model (with two identical branches that were not specifically identified within the cave system) to a one (identified) pocket in the cavern and a very broad basin (identified, of course) that serves as the other branch of the U-tube. Our methodology is to apply familiar fluid dynamics principles to the situation that occurred in the cave. We did so, step-by-step, on the basis of our interviews with four out of the five surviving cave-divers. Namely, we dissected their testimonies to arrive at a physically plausible scenario determined on basis of a fluid dynamics application to the natural flow in the cave and the flow induced by the compressed air released by the divers as well as the collapsed mud. We found that the oscillation period was larger than what we earlier calculated (still relevant to the case, nevertheless), and that, in contrast to what most cave divers believe, there was a temporary

Analysis of the Condition and Development Opportunities of Cave Tourism in Primorsko-Goranska County

Directory of Open Access Journals (Sweden)

Rade Knežević

2011-04-01

Full Text Available This paper examines caves as morphological factors of tourism development in Primorsko-Goranska County. The primary aim is to promote cave heritage parallel with the development of cave tourism. The methodological framework is based on analyzing material in the archives of tourist boards, taking an inventory of cave resources (case study, conducting interviews, and making a SWOT analysis of cave tourism development. Research results show that caves represent a complex resource in the tourist trade of Primorsko-Goranska County, to which little importance has been attached up to date (priority being given to mass tourism. In the context of tourism development, caves fall into four groups. The first group comprises caves that have a long tradition, but show signs of aging as a tourism product. The second group includes caves that were once open to the public, but were later closed for some reason. The third group consists of caves on the seaside or seabed visited by speleologists-divers. The fourth group is made up of potential cave sites that have been evaluated as being attractive, but is located in hard-to-access areas, making their valorisation in tourism purpose more difficult. Only Lokvarka Cave has a substantial influence on the development of special interest tourism in Lokve, while in all other cases, the role of caves in the tourism offering needs to be revalorised.

The potential of perennial cave ice in isotope palaeoclimatology

International Nuclear Information System (INIS)

Yonge, Charles J.; MacDonald, William D.

1999-01-01

Perennial ice from caves on and to the east of the Canadian Great Divide yield delta O 18 and delta D values which are usually high measurements where compared with the average precipitation for the region. Furthermore, these ice data fall below and along lines of lower slope than the Global Meteoric Water Line. To explain the observed relationships, we propose the following process. a vapour-ice isotopic fractionation mechanism operates on warm season vapour when it precipitates as hoar ice on entering the caves. The subsequent fall of hoar to the cave floor through mechanical overloading along with ice derived from ground-water seepage (with a mean annual isotopic composition), results in massive ice formation of a mixed composition. This mixed composition is what is observed in the characteristic relationships found here. Such findings suggest that a warm versus cold climate interpretation for ancient cave ice may be the opposite of that found in the more familiar polar and glacial ice caves. (Author) 3 figs., 1 tab., 12 refs

Caving thickness effects of surrounding rocks macro stress shell evolving characteristics

Institute of Scientific and Technical Information of China (English)

XIE Guang-xiang; YANG Ke

2009-01-01

In order to explore the influence of different caving thicknesses on the MSS dis-tribution and evolving characteristics of surrounding rocks in unsymmetrical disposal and fully mechanized top-coal caving (FMTC), based on unsymmetrical disposal characteris-tics, the analyses of numerical simulation, material simulation and in-situ observation were synthetically applied according to the geological and technical conditions of the 1151(3) working face in Xieqiao Mine. The results show that the stress peak value of the MSS-base and the ratio of MSS-body height to caving thickness are nonlinear and inversely proportional to the caving thickness. The MSS-base width, the MSS-body height, the MSS-base distance to working face wall and the rise distance of MSS-base beside coal pillar are nonlinear and directly proportional to the caving thickness. The characteristics of MSS distribution and its evolving rules of surrounding rocks and the integrated caving thickness effects are obtained. The investigations will provide lots of theoretic references to the surrounding rocks' stability control of the working face and roadway, roadway layout, gas extraction and exploitation, and efficiency of caving, etc.

The biogeochemistry of anchialine caves: Progress and possibilities

Science.gov (United States)

Pohlman, John W.

2011-01-01

Recent investigations of anchialine caves and sinkholes have identified complex food webs dependent on detrital and, in some cases, chemosynthetically produced organic matter. Chemosynthetic microbes in anchialine systems obtain energy from reduced compounds produced during organic matter degradation (e.g., sulfide, ammonium, and methane), similar to what occurs in deep ocean cold seeps and mud volcanoes, but distinct from dominant processes operating at hydrothermal vents and sulfurous mineral caves where the primary energy source is mantle derived. This review includes case studies from both anchialine and non-anchialine habitats, where evidence for in situ chemosynthetic production of organic matter and its subsequent transfer to higher trophic level metazoans is documented. The energy sources and pathways identified are synthesized to develop conceptual models for elemental cycles and energy cascades that occur within oligotrophic and eutrophic anchialine caves. Strategies and techniques for testing the hypothesis of chemosynthesis as an active process in anchialine caves are also suggested.

Morphology and evolution of sulphuric acid caves in South Italy

Science.gov (United States)

D'Angeli, Ilenia M.; De Waele, Jo; Galdenzi, Sandro; Madonia, Giuliana; Parise, Mario; Vattano, Marco

2016-04-01

Sulphuric acid speleogenesis (SAS) related to the upwelling of acid water enriched in H2S and CO2 represents an unusual way of cave development. Since meteoric infiltration waters are not necessarily involved in speleogenesis, caves can form without the typical associated karst expressions (i.e. dolines) at the surface. The main mechanism of sulphuric acid dissolution is the oxidation of H2S (Jones et al., 2015) which can be amplified by bacterial mediation (Engel et al., 2004). In these conditions, carbonate dissolution associated with gypsum replacement, is generally believed to be faster than the normal epigenic one (De Waele et al., 2016). In Italy several SAS caves have been identified, but only few systems have been studied in detail: Frasassi and Acquasanta Terme (Marche)(Galdenzi et al., 2010), Monte Cucco (Umbria) (Galdenzi & Menichetti, 1995), and Montecchio (Tuscany) (Piccini et al., 2015). Other preliminary studies have been carried out in Calabria (Galdenzi, 2007) and Sicily (De Waele et al., 2016). Several less studied SAS cave systems located in South Italy, and in particular in Apulia (Santa Cesarea Terme), Sicily (Acqua Fitusa, Acqua Mintina) and Calabria (Mt. Sellaro and Cassano allo Ionio) have been selected in the framework of a PhD thesis on SAS caves and their speleogenesis. Using both limestone tablet weight loss (Galdenzi et al., 2012) and micro erosion meter (MEM) (Furlani et al., 2010) methods the dissolution rate above and under water in the caves will be quantified. Geomorphological observations, landscape analysis using GIS tools, and the analysis of gypsum and other secondary minerals (alunite and jarosite) (stable isotopes and dating) will help to reconstruct the speleogenetic stages of cave formation. Preliminary microbiological analysis will determine the microbial diversity and ecology in the biofilms. References Engel S.A., Stern L.A., Bennett P.C., 2004 - Microbial contributions to cave formation: New insight into sulfuric acid

Development of the high-level waste high-temperature melter feed preparation flowsheet for vitrification process testing

International Nuclear Information System (INIS)

Seymour, R.G.

1995-01-01

High-level waste (HLW) feed preparation flowsheet development was initiated in fiscal year (FY) 1994 to evaluate alternative flowsheets for preparing melter feed for high-temperature melter (HTM) vitrification testing. Three flowsheets were proposed that might lead to increased processing capacity relative to the Hanford Waste Vitrification Plant (HWVP) and that were flexible enough to use with other HLW melter technologies. This document describes the decision path that led to the selection of flowsheets to be tested in the FY 1994 small-scale HTM tests. Feed preparation flowsheet development for the HLW HTM was based on the feed preparation flowsheet that was developed for the HWVP. This approach allowed the HLW program to build upon the extensive feed preparation flowsheet database developed under the HWVP Project. Primary adjustments to the HWVP flowsheet were to the acid adjustment and glass component additions. Developmental background regarding the individual features of the HLW feed preparation flowsheets is provided. Applicability of the HWVP flowsheet features to the new HLW vitrification mission is discussed. The proposed flowsheets were tested at the laboratory-scale at Pacific Northwest Laboratory. Based on the results of this testing and previously established criteria, a reductant-based flowsheet using glycolic acid and a nitric acid-based flowsheet were selected for the FY 1994 small-scale HTM testing

Speleothem (Cave Deposit) Data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Records of past temperature, precipitation, and other aspects of climate derived from mineral deposits found in caves. Parameter keywords describe what was measured...

Phylogeography of Sardinian cave salamanders (genus Hydromantes) is mainly determined by geomorphology.

Science.gov (United States)

Chiari, Ylenia; van der Meijden, Arie; Mucedda, Mauro; Lourenço, João M; Hochkirch, Axel; Veith, Michael

2012-01-01

Detecting the factors that determine the interruption of gene flow between populations is key to understanding how speciation occurs. In this context, caves are an excellent system for studying processes of colonization, differentiation and speciation, since they represent discrete geographical units often with known geological histories. Here, we asked whether discontinuous calcareous areas and cave systems represent major barriers to gene flow within and among the five species of Sardinian cave salamanders (genus Hydromantes) and whether intraspecific genetic structure parallels geographic distance within and among caves. We generated mitochondrial cytochrome b gene sequences from 184 individuals representing 48 populations, and used a Bayesian phylogeographic approach to infer possible areas of cladogenesis for these species and reconstruct historical and current dispersal routes among distinct populations. Our results show deep genetic divergence within and among all Sardinian cave salamander species, which can mostly be attributed to the effects of mountains and discontinuities in major calcareous areas and cave systems acting as barriers to gene flow. While these salamander species can also occur outside caves, our results indicate that there is a very poor dispersal of these species between separate cave systems.

Palaeoclimate Research in Villars Cave (Dordogne, SW-France

Directory of Open Access Journals (Sweden)

Genty Dominique

2008-10-01

Full Text Available Villars Cave is a typical shallow cave from South-West France (45.44°N; 0.78°E; 175 m asl that has provided several speleothempalaeoclimatic records such as the millennial scale variability of the Last Glacial period and the Last Deglaciation. Monitoring theVillars cave environment over a 13-year period has helped in the understanding of the stable isotopic speleothem content and inthe hydrology. For example, it was demonstrated that most of the calcite CaCO3 carbon comes from the soil CO2, which explainsthe sensitivity of the δ13C to any vegetation and climatic changes. Drip rate monitoring, carried out under four stalactites from thelower and upper galleries, has shown a well marked seasonality of the seepage water with high flow rates during winter and spring.A time delay of about two months is observed between the water excess (estimated from outside meteorological stations and thedrip rate in the cave. A great heterogeneity in the flow rate amplitude variations and in the annual quantity of water between twonearby stalactites is observed, confirming the complexity of the micro-fissure network system in the unsaturated zone. At a dailyscale, the air pressure and drip rates are anti-correlated probably because of pressure stress on the fissure network. Cave air CO2concentration follows soil CO2 production and is correlated with its δ13C content. Since the beginning of the monitoring, the cave airtemperature, in both lower and upper galleries, displays a warming trend of ~+0.4°C±0.1/10yrs. This might be the consequence ofthe outside temperature increase that reaches the Villars Cave galleries through thermal wave conduction. Chemistry monitoringover a few years has shown that the seepage water of the lower gallery stations is significantly more concentrated in trace and minorelements (i.e. Sr, Mg, Ba, U than the upper stations, probably due to the 10-20 m depth difference between these galleries, whichimplies a different seepage pathway

Determination of the Radon Concentration and Radioactivity Level in Karaca Cave

International Nuclear Information System (INIS)

Kara, A.

2008-01-01

In this study, the radon gas concentration in the Karaca cave which is open to tourism has been determined and the negative effects of radon gas on people were discussed. Karaca cave (Gumushane) is visited by many tourists every year. The measurements of radon gas concentration which affects the health of human beings negatively and even causes the lung cancer when it reaches high points have been done for the summer and winter season. LR-115 passive radon detector was used to determine radon concentrations in the cave both winter and summer season. The average radon concentration in the Karaca cave were determined as 823 Bq/m 3 and 1023 Bq/m 3 for the summer and winter season, respectively. Moreover, to find out the natural radioactivity in the cave, the gamma spectroscopic analysis of soil, stone and stalagmite samples were carried out and their relations with the radon gas in the cave atmosphere was analyzed

Joule-Heated Ceramic-Lined Melter to Vitrify Liquid Radioactive Wastes Containing Am241 Generated From MOX Fuel Fabrication in Russia

International Nuclear Information System (INIS)

Smith, E C; Bowan II, B W; Pegg, I; Jardine, L J

2004-01-01

The governments of the United Stated of America and the Russian Federation (RF) signed an Agreement September 1, 2000 to dispose of weapons plutonium that has been designated as no longer required for defense purposes. The Agreement declares that each country will disposition 34MT of excess weapons grade plutonium from their stockpiles. The preferred disposition technology is the fabrication of mixed oxide (MOx) fuel for use or burning in pressurized water reactors to destroy the plutonium. Implementation of this Agreement will require the conversion of plutonium metal to oxide and the fabrication of MOx fuel within the Russian Federation. The MOx fuel fabrication and metal to oxide conversion processes will generate solid and liquid radioactive wastes containing trace amounts of plutonium, neptunium, americium, and uranium requiring treatment, storage, and disposal. Unique to the Russian MOx fuel fabrication facility's flow-sheet is a liquid waste stream with high concentrations (∼1 g/l) of 241 Am and non radioactive silver. The silver is used to dissolve PuO 2 feed materials to the MOx fabrication facility. Technical solutions are needed to treat and solidify this liquid waste stream. Alternative treatment technologies for this liquid waste stream are being evaluated by a Russian engineering team. The technologies being evaluated include borosilicate and phosphate vitrification alternatives. The evaluations are being performed at a conceptual design level of detail under a Lawrence Livermore National Laboratory (LLNL) contract with the Russian organization TVEL using DOE NA-26 funding. As part of this contract, the RF team is evaluating the technical and economic feasibility of the US borosilicate glass vitrification technology based on a Duratek melter to solidify this waste stream into a form acceptable for storage and geologic disposal. The composition of the glass formed from treating the waste is dictated by the concentration of silver and americium it

Vitrification of SRP waste by a slurry-fed ceramic melter

International Nuclear Information System (INIS)

Wicks, G.G.

1980-01-01

Savannah River Plant (SRP) high-level waste (HLW) can be vitrified by feeding a slurry, instead of a calcine, to a joule-heated ceramic melter. Potential advantages of slurry feeding include (1) use of simpler equipment, (2) elimination of handling easily dispersed radioactive powder, (3) simpler process control, (4) effective mixing, (5) reduced off-gas volume, and (6) cost savings. Assessment of advantages and disadvantages of slurry feeding along with experimental studies indicate that slurry feeding is a promising way of vitrifying waste

Urban landscape and architectural workshop Škocjan Caves 2007

Directory of Open Access Journals (Sweden)

Andrej Mahovič

2012-01-01

Full Text Available The fundamental aim and purpose of the Škocjan Caves 2007 student workshop was for students participating in the seminar of the Faculty of Architecture in Ljubljana to recognise and address some specific spatial and design issues for the further sustainable development of the Škocjan Caves. The working hypothesis of the workshop was that, in spite of significant results in the protection and development of the Caves which have been achieved in the past ten years, it is still necessary to address some spatial issues through an academic process, and to offer different architectural and spatial solutions. The aforesaid is even more important as the Caves are recognised as the only natural and cultural heritage of the Republic of Slovenia to be listed as a UNESCO World Heritage site since 1986.

Tamarugite from Diana Cave (SW Romania) -first true karst occurrence

Science.gov (United States)

Pušcaš, C. M.; Onac, B. P.; Effenberger, H. S.; Povarǎ, I.

2012-04-01

Diana Cave is located within the town limits of Baile Herculane (SW Romania) and develops as a 14 m long, westward oriented, unique passage guided by the Diana fault [1]. At the far end of the cave, the thermo-mineral Diana Spring wells forth. In the early 1970s a mine gallery that intersected the cave was created to drain the water into a pumping station and the original cave passage was somewhat altered and reinforced with concrete. Today the concrete and the silty limestone cave walls are heavily corroded by H2SO4 outgassing from the hot water (ca. 50°C) and display abundant gypsum crusts, soggy aggregates of native S, and a variety of more exotic sulfates. Among them, a mineral that has been previously identified in caves only in connection to volcanic activity, either as thermal springs or fumaroles [2]: tamarugite [NaAl(SO4)26H2O]. It was [3] that first mentioned the occurrence of this Na and Al sulfate in Diana Cave, our research aiming to give a detailed description of this mineral, its paragenesis, and mechanisms of precipitation. Recently, tamarugite has also been identified in a sulfuric acid cave from Greece [4]. Along with powder X-ray diffractions coupled with Rietveld refinement, scanning electron microscope, and electron probe micro-analysis, δ18O and δ34S compositions of the sulfate mineral as well as precipitates from the water were analyzed to identify and better constrain the genesis of this rare sulfate. Regrettably, the crystal size of our specimens is inappropriate for identification by means of single crystal X-ray diffraction. Physical and chemical parameters of Diana Spring were as well measured on several occasions. Geochemical analysis suggests that the minute, white tamarugite flakes precipitated in Diana Cave as a result of the interactions between the thermo-mineral water or water vapor and the original limestone bedrock and concrete that blankets the mine gallery. [1] Povara, I., Diaconu, G., Goran, C. (1972). Observations pr

Depth Perception in Cave and Panorama

DEFF Research Database (Denmark)

Mullins, Michael; Strojan, Tadeja Zupancic

2004-01-01

This study compares aspects of spatial perception in a physical environment and its virtual representations in a CAVE and Panorama, derived from recent research. To measure accuracy of spatial perception, participants in an experiment were asked to look at identical objects in the three environme......, learning and training in virtual environments; in architectural education; and participatory design processes, in which the dialogue between real and imagined space may take place in virtual . reality environments...... environments and then locate them and identify their shape on scaled drawings.  Results are presented together with statistical analysis. In a discussion of the results, the paper addresses the two hypothetical assertions ? that depth perception in physical reality and its virtual representations in CAVE......This study compares aspects of spatial perception in a physical environment and its virtual representations in a CAVE and Panorama, derived from recent research. To measure accuracy of spatial perception, participants in an experiment were asked to look at identical objects in the three...

Management in a neotropical show cave: planning for invertebrates conservation

Directory of Open Access Journals (Sweden)

Thais Giovannini Pellegrini

2012-07-01

Full Text Available Lapa Nova is a dolomitic cave about 4.5 km long located in northwestern Minas Gerais state, Brazil. The cave experiences intense tourism, concentrated over a single period of the year, during the Feast of Our Lady of Lapa. In order to evaluate the impacts felt by the invertebrate community from this tourism, a new methodology was proposed. Four types of areas (intense visitation area, outlying visitation areas, moderate visitation areas and no-visitation areas were sampled for invertebrates. There was one sampling prior and another on the last day of the 128th feast, to evaluate the effects of visitation on cave-dwelling invertebrates. Results show that invertebrate populations residing in more intensely visited areas of the cave undergo changes in distribution following the event. As a consequence of tourism, invertebrates shift to outlying locations from the visited area, which serve as refuges to the communities. Apparently, the fact that there are places inside Lapa Nova inaccessible to tourists reduces the impact suffered by the invertebrate community, as those sites serve as refuges for cave-dwelling organisms during the pilgrimage. A proper management plan was devised for the tourism/religious use of the cave. It consists basically of delimiting marked pathways for tourists, allowing invertebrates to seek shelter at locations outside visited areas and keeping no-visitation areas off-limits to tourism based on the results of the visitation effects on cave-dwelling invertebrates.

Candidate cave entrances on Mars

Science.gov (United States)

Cushing, Glen E.

2012-01-01

This paper presents newly discovered candidate cave entrances into Martian near-surface lava tubes, volcano-tectonic fracture systems, and pit craters and describes their characteristics and exploration possibilities. These candidates are all collapse features that occur either intermittently along laterally continuous trench-like depressions or in the floors of sheer-walled atypical pit craters. As viewed from orbit, locations of most candidates are visibly consistent with known terrestrial features such as tube-fed lava flows, volcano-tectonic fractures, and pit craters, each of which forms by mechanisms that can produce caves. Although we cannot determine subsurface extents of the Martian features discussed here, some may continue unimpeded for many kilometers if terrestrial examples are indeed analogous. The features presented here were identified in images acquired by the Mars Odyssey's Thermal Emission Imaging System visible-wavelength camera, and by the Mars Reconnaissance Orbiter's Context Camera. Select candidates have since been targeted by the High-Resolution Imaging Science Experiment. Martian caves are promising potential sites for future human habitation and astrobiology investigations; understanding their characteristics is critical for long-term mission planning and for developing the necessary exploration technologies.

Differential preservation of vertebrates in Southeast Asian caves

Directory of Open Access Journals (Sweden)

Julien Louys

2017-09-01

Full Text Available Caves have been an important source of vertebrate fossils for much of Southeast Asia, particularly for the Quaternary. Despite this importance, the mechanisms by which vertebrate remains accumulate and preserve in Southeast Asian caves has never been systematically reviewed or examined. Here, we present the results of three years of cave surveys in Indonesia and Timor-Leste, describing cave systems and their attendant vertebrate accumulations in diverse geological, biogeographical, and environmental settings. While each cave system is unique, we find that the accumulation and preservation of vertebrate remains are highly dependent on local geology and environment. These factors notwithstanding, we find the dominant factor responsible for faunal deposition is the presence or absence of biological accumulating agents, a factor directly dictated by biogeographical history. In small, isolated, volcanic islands, the only significant accumulation occurs in archaeological settings, thereby limiting our understanding of the palaeontology of those islands prior to human arrival. In karstic landscapes on both oceanic and continental islands, our understanding of the long-term preservation of vertebrates is still in its infancy. The formation processes of vertebrate-bearing breccias, their taphonomic histories, and the criteria used to determine whether these represent syngenetic or multiple deposits remain critically understudied. The latter in particular has important implications for arguments on how breccia deposits from the region should be analysed and interpreted when reconstructing palaeoenvironments.

X-ray analysis of aerosol samples from a therapeutic cave

Energy Technology Data Exchange (ETDEWEB)

Alfoeldy, B. E-mail: alfi@sunserv.kfki.hu; Toeroek, Sz.; Kocsonya, A.; Szokefalvi-Nagy, Z.; Balla, Md.I

2001-04-01

Cave therapy is an efficient therapeutic method to cure asthma, the exact healing effect, however, is not clarified, yet. This study is motivated by the basic assumption that aerosols do play the key role in the cave therapy. This study is based on measurements of single aerosol particles originating from a therapeutic cave of Budapest, Hungary (Szemlohegyi cave). Aerosol particles have been collected in the regions arranged for the therapeutic treatment. Samples were further analysed for chemical and morphological aspects, determining the particle size distribution and classifying them according to elemental composition. Three particle classes have been detected based on major element concentration: alumino-silicate, quartz and calcium carbonate. Calcium ions have well-known physiological influence: anti-spastic, anti-inflammation and excretion reducing effects. Inflammation, accompanying spasm and extreme excretion production cause the smothering stigma, the so-called asthma. Therefore it could be assumed that calcium ions present in high concentration in the cave's atmosphere is the major cause of the healing effect.

X-ray analysis of aerosol samples from a therapeutic cave

International Nuclear Information System (INIS)

Alfoeldy, B.; Toeroek, Sz.; Kocsonya, A.; Szokefalvi-Nagy, Z.; Balla, Md.I.

2001-01-01

Cave therapy is an efficient therapeutic method to cure asthma, the exact healing effect, however, is not clarified, yet. This study is motivated by the basic assumption that aerosols do play the key role in the cave therapy. This study is based on measurements of single aerosol particles originating from a therapeutic cave of Budapest, Hungary (Szemlohegyi cave). Aerosol particles have been collected in the regions arranged for the therapeutic treatment. Samples were further analysed for chemical and morphological aspects, determining the particle size distribution and classifying them according to elemental composition. Three particle classes have been detected based on major element concentration: alumino-silicate, quartz and calcium carbonate. Calcium ions have well-known physiological influence: anti-spastic, anti-inflammation and excretion reducing effects. Inflammation, accompanying spasm and extreme excretion production cause the smothering stigma, the so-called asthma. Therefore it could be assumed that calcium ions present in high concentration in the cave's atmosphere is the major cause of the healing effect

WP-Cave - assessment of feasibility, safety and development potential

International Nuclear Information System (INIS)

1989-09-01

According to SKB R and D-programme 1986, alternative disposal methods will be investigated to provide a basis for selecting a site and a repository system for the Swedish spent nuclear fuel. The present report is a comparison between the WP-Cave and the reference concept KBS-3. The comparison has resulted in the following conclusions: - Both concepts are judged to be able to provide adequate safety. - A utilization of the potential of the WP-Cave requires, however, extensive development in areas where the current state of knowledge and available data are incomplete. - The higher temperatures in the WP-Cave lead to greater uncertainty as to long-term performance. Reducing this uncertainty would require many yaers of research and substantial resources. - Both repositories, including the barriers they incorporate, could be built with a normal adaption of available technology. -It is not possible to say today whether it would be simpler to find suitable sites for one design or the other. - The WP-Cave is considerably more expensive. A future research direction based on a concentrated emplacement of spent fuel along the lines of the WP-Cave is therefore judged to entail greater uncertainty as regards the possibilities of achieving acceptable safety and to require greater resources for research and development, at the same time as the costs of building the repository would be higher. The studies of the WP-Cave as an integral system should therfore be discontinued. Certain barrier designs in the WP-Cave could also be utulized in repository designs with lower temperature, for example the reduction potential of the steel canisters and the hydraulic cage's diversion of groundwater. Studies within these areas are being conducted within SKB and should continue

A Joule-Heated Melter Technology For The Treatment And Immobilization Of Low-Activity Waste

International Nuclear Information System (INIS)

Kelly, S.E.

2011-01-01

This report is one of four reports written to provide background information regarding immobilization technologies remaining under consideration for supplemental immobilization of Hanford's low-activity waste. This paper provides the reader a general understanding of joule-heated ceramic lined melters and their application to Hanford's low-activity waste.

The role of natural ventilation in the exposure to radon in the Postojna Cave

Science.gov (United States)

Gregorič, A.; Smerajec, M.; Vaupotič, J.

2012-04-01

Postojna Cave is the biggest of 21 show caves in Slovenia and one of present day's most visited show caves in the world. Long and branched out cave system, large entrances at different levels, inflow of the Pivka river, and large variation of the outdoor air temperature and precipitation, make the Postojna Cave also a very complex climatic system in which each part shows different conditions. The cave is only naturally ventilated and it is therefore characterised by high radon concentration, which depends on the ventilation regime in different seasons, resulting in typical annual cycles of radon levels in the cave air. Postojna Cave is a typical horizontal cave, where the difference between outside and cave air temperature represents the main driving force for air circulation. In winter, when the cave temperature is higher than outside, cave air is released from the cave into the outdoor atmosphere due to the air draught caused by the 'chimney effect', thus allowing fresh and cold outdoor air to enter the cave through low lying openings. This effect is not operative in summer, when the outside temperature is higher than in the cave, and air draught is minimal or reversed. In addition, air circulation can be locally altered due to other processes, like changing level of Pivka river during the rainy season and local geomorphologic characteristics of cave passages. High radon concentration in the Postojna Cave is the reason for thorough studies of the methodology for dose estimates of the personnel working in the cave. Due to high relative humidity and low air circulation, the cave air is characterised by very low particle concentration, which play an important role in radon dosimetry. Therefore parallel monitoring of radioactive aerosols of radon decay products (RnDP) and general (non-radioactive) aerosols in the particle size range of 10-1100 nm was performed in the air of Postojna Cave at the lowest point of tourist path in summer, winter and both transitional

Visualization framework for CAVE virtual reality systems

OpenAIRE

Kageyama, Akira; Tomiyama, Asako

2016-01-01

We have developed a software framework for scientific visualization in immersive-type, room-sized virtual reality (VR) systems, or Cave automatic virtual environment (CAVEs). This program, called Multiverse, allows users to select and invoke visualization programs without leaving CAVE’s VR space. Multiverse is a kind of immersive “desktop environment” for users, with a three-dimensional graphical user interface. For application developers, Multiverse is a software framework with useful class ...

Investigation of Sediment Pathways and Concealed Sedimentological Features in Hidden River Cave, Kentucky

Science.gov (United States)

Feist, S.; Maclachlan, J. C.; Reinhardt, E. G.; McNeill-Jewer, C.; Eyles, C.

2016-12-01

Hidden River Cave is part of a cave system hydrogeologically related to Mammoth Cave in Kentucky and is a multi-level active cave system with 25km of mapped passages. Upper levels experience flow during flood events and lower levels have continuously flowing water. Improper industrial and domestic waste disposal and poor understanding of local hydrogeology lead to contamination of Hidden River Cave in the early 1940s. Previously used for hydroelectric power generation and as a source of potable water the cave was closed to the public for almost 50 years. A new sewage treatment plant and remediation efforts since 1989 have improved the cave system's health. This project focuses on sedimentological studies in the Hidden River Cave system. Water and sediment transport in the cave are being investigated using sediment cores, surface sediment samples and water level data. An Itrax core scanner is used to analyze sediment cores for elemental concentrations, magnetic susceptibility, radiography, and high resolution photography. Horizons of metal concentrations in the core allow correlation of sedimentation events in the cave system. Thecamoebian (testate amoebae) microfossils identified in surface samples allow for further constraint of sediment sources, sedimentation rates, and paleoclimatic analysis. Dive recorders monitor water levels, providing data to further understand the movement of sediment through the cave system. A general time constraint on the sediment's age is based on the presence of microplastic in the surface samples and sediment cores, and data from radiocarbon and lead-210 dating. The integration of various sedimentological data allows for better understanding of sedimentation processes and their record of paleoenvironmental change in the cave system. Sediment studies and methodologies from this project can be applied to other karst systems, and have important applications for communities living on karst landscapes and their water management policies.

Uranium-series dating of fossil bones from alpine caves

International Nuclear Information System (INIS)

Leitner-Wild, E.; Steffan, I.

1993-01-01

During the course of an investigation of fossil cave bear populations the uranium-series method for absolute age determination has been applied to bone material. The applicability of the method to bone samples from alpine caves is demonstrated by the concordance of U/Th and U/Pa ages and cross-checks with the radiocarbon method. Stratigraphic agreement between bone ages and carbonate speleothem ages also indicates the potential of the uranium-series method as a suitable tool for the age determination of fossil bones from alpine cave environments. (Author)

Modeling of luminance distribution in CAVE-type virtual reality systems

Science.gov (United States)

Meironke, Michał; Mazikowski, Adam

2017-08-01

At present, one of the most advanced virtual reality systems are CAVE-type (Cave Automatic Virtual Environment) installations. Such systems are usually consisted of four, five or six projection screens and in case of six screens arranged in form of a cube. Providing the user with a high level of immersion feeling in such systems is largely dependent of optical properties of the system. The modeling of physical phenomena plays nowadays a huge role in the most fields of science and technology. It allows to simulate work of device without a need to make any changes in the physical constructions. In this paper distribution of luminance in CAVE-type virtual reality systems were modelled. Calculations were performed for the model of 6-walled CAVE-type installation, based on Immersive 3D Visualization Laboratory, situated at the Faculty of Electronics, Telecommunications and Informatics at the Gdańsk University of Technology. Tests have been carried out for two different scattering distribution of the screen material in order to check how these characteristicinfluence on the luminance distribution of the whole CAVE. The basis assumption and simplification of modeled CAVE-type installation and results were presented. The brief discussion about the results and usefulness of developed model were also carried out.

Tamarugite in the Steam-Condensate Alteration Paragenesis in Diana Cave (SW Romania)

Science.gov (United States)

Puscas, C. M.; Onac, B. P.; Effenberger, H. S.; Povară, I.

2012-12-01

The double-salt hydrate tamarugite [NaAl(SO4)2 6H2O] is an uncommon mineral in the cave environment, forming as a result of chemical reactions between water and bedrock only under very specific conditions. The Diana Cave hosts a unique tamarugite occurrence, the first one to be reported from a typical karst environment. The cave is located within the limits of Băile Herculane township in the Cerna Mountains, SW Romania. It consists of a 14 m long, westward-oriented single passage, developed along the Diana Fault. In 1974 a concrete-clad mine gallery was created to channel the thermal water (Diana 1+2 Spring) flowing through the cave to a pumping station. The spring's chemical and physical parameters fluctuated through time, averaging 51.98° C, discharge of 0.96 Ls-1, pH of 7.46, 5768.66 ppm TDS, 9303 μScm-1 conductivity, 5.02 salinity. The major chemical components of the thermo-mineral water in Diana Cave are, Na+ (1392.57 ppm), K+ (58.55 ppm), Ca2+ (725.16 ppm), Mg2+ (10.78 ppm), Cl- (3376.83 ppm), and SO42- (92.27 ppm), and H2S (24.05 ppm), with traces of Si, Fe2+, Br+, I-, and Li+. The general air circulation pattern within the cave is fairly simple: cold air from the outside sweeps into the cave along the floor, heats up at the contact with the thermo-mineral water, ascends, and exists the cave along the ceiling. At the contact with the cold walls of the Diana Cave, the hot steam condenses and gives rise to a rich and exotic sulfate-mineral paragenesis (including halotrichite-series minerals, gypsum, bassanite, anhydrite, epsomite, alunite, halite, native sulfur, etc.). The most exotic minerals precipitate at or below the contact between the Tithonic - Neocomian limestone and the overlaying Cretaceous shaly limestone, as a result of steam-condensate alteration. Minerogenetic mechanisms responsible for the peculiar sulfate mineral assemblage in Diana Cave are evaporation, oxidation, hydrolysis, double exchange reactions, and deposition from vapours or

First assessment on the air CO2 dynamic in the show caves of tropical karst, Vietnam

Directory of Open Access Journals (Sweden)

Duc A. Trinh

2018-01-01

Full Text Available In this study, air, water, and host rock in show caves in a Vietnam’s karst region was monitored and analyzed to identify the ventilation regime and track the cave air CO2 sources. In general, the studied caves are well ventilated. In dynamic – multiple entrance caves, air ventilation is described with the use of U shape model. In static – single entrance cave, air circulation is explained by cold air trap model. Both ventilation models suggest that air is more circulated in winter than in summer. Seasonally, the cave air CO2 increases from early spring to summer. Value in the deepest part of the single-entrance cave is approximately 1,000 ppmv and 8,000 ppmv in early spring and summer, respectively. In multiple-entrance and wet caves, CO2 level is fairly constant all over the show section, increasing from 500 ppmv in early spring to 2,000 ppmv in summer. Data of microclimate, CO2 content, and particularly δ13C show that cave air, particularly in single entrance cave, has higher CO2 concentration during summer due to a stagnation of cave air circulation and an elevated CO2 input from soil and epikarst. The cave air CO2 increase is also observed after intense rainfalls. A factor that increase cave air CO2 in show caves during the festive days could probably be huma n exhaling but the extent of human factor in these studied cave systems should be further investigated. Cave waters including cave pools and streams mediate CO2 level in wet caves. Above all, the atmospheric fraction of CO2 is always dominant (>60% in all cave sections.

Measurements of Aerosol Characteristics in Skocjan Caves

International Nuclear Information System (INIS)

Jovanovic, P.

2013-01-01

Measurements of radon concentration and radon progeny concentration (attached and unattached) have been performed in Skocjan caves. In the same time also aerosol concentration (PM 10 ), aerosol size distribution with ten stage Hauke impactor and Scanning Mobility Particle Sizer - SMPS have been performed. The idea was to find impact of outer air and visitors to the aerosol characteristics of cave air. Measurements with impactor have been implemented in summer and winter period, with SMPS only in summer period. Radon concentrations ranged in winter period in region from 500 to 1000 Bq/m 3 , equilibrium factor was about 55 %. In summer period radon concentration increased up to 10 kBq/m 3 , equilibrium factor was about 45 %, and unattached fraction went up to 20 %. Measurements of aerosol size distribution show lower aerosol sizes in winter season (around 1 μm) and bigger aerosol sizes in summer season (around 3 - 6 μm). We could not find good correlation between unattached fraction and aerosol size distribution. Also we could not find clear impact of visitors to the air characteristics in cave. Probably our measuring location was too close to the entrance and the impact of outer air was too high. We will repeat measurements deeper in cave to find better results.(author)

Sex-specific local life-history adaptation in surface- and cave-dwelling Atlantic mollies (Poecilia mexicana).

Science.gov (United States)

Riesch, Rüdiger; Reznick, David N; Plath, Martin; Schlupp, Ingo

2016-03-10

Cavefishes have long been used as model organisms showcasing adaptive diversification, but does adaptation to caves also facilitate the evolution of reproductive isolation from surface ancestors? We raised offspring of wild-caught surface- and cave-dwelling ecotypes of the neotropical fish Poecilia mexicana to sexual maturity in a 12-month common garden experiment. Fish were raised under one of two food regimes (high vs. low), and this was crossed with differences in lighting conditions (permanent darkness vs. 12:12 h light:dark cycle) in a 2 × 2 factorial design, allowing us to elucidate potential patterns of local adaptation in life histories. Our results reveal a pattern of sex-specific local life-history adaptation: Surface molly females had the highest fitness in the treatment best resembling their habitat of origin (high food and a light:dark cycle), and suffered from almost complete reproductive failure in darkness, while cave molly females were not similarly affected in any treatment. Males of both ecotypes, on the other hand, showed only weak evidence for local adaptation. Nonetheless, local life-history adaptation in females likely contributes to ecological diversification in this system and other cave animals, further supporting the role of local adaptation due to strong divergent selection as a major force in ecological speciation.

The genesis of a lava cave in the Deccan Volcanic Province (Maharashtra, India

Directory of Open Access Journals (Sweden)

Nikhil R. Pawar

2016-01-01

Full Text Available Lava tubes and channels forming lava distributaries have been recognized from different parts of western Deccan Volcanic Province (DVP. Openings of smaller dimension have been documented from the pāhoehoe flows around Pune, in the western DVP. A small lava cave is exposed in Ghoradeshwar hill, near Pune. Detailed field studies of the physical characteristics, structure and morphology of the flows hosting the lava tube has been carried out. This is the first detailed documentation of a lava cave from the DVP. The lava cave occurs in a compound pāhoehoe flow of Karla Formation, characterized by the presence of lobes, toes and small scale features like squeeze-ups. Field observations and measurements reveal that the dimensions of the cave are small, with low roof and a maximum width of 108 cm. The cave morphology along the 20 m passage varies from circular to semi-circular, with a twilight zone to the north. The gentle micro-topography at Ghoradeshwar controlled the advancement of pāhoehoe lobes and toes within the sheet lobe. The pre-flow gradients towards the north led to the progression of flow from the east, where the cave opening is presently seen. Dimensions and related morphology of the lava cave suggest that it can be best described as a small sub-crustal cave formed by draining of an inflated of pāhoehoe lava lobe. At Ghoradeshwar, besides the natural lava cave, Buddhist caves carved in pāhoehoe lava flows are also observed, indicating that early man took advantage of the existing openings in pāhoehoe flows and sculpted the caves to suit their requirements.

High Resolution Time Series Cave Ventilation Processes and the Effects on Cave Air Chemistry and Drip Waters: Speleoclimatology and Proxy Calibration

Science.gov (United States)

Kowalczk, A. J.; Froelich, P. N.; Gaffka, C.; Tremaine, D.

2008-12-01

Continuous high resolution (sub-hourly), long-term (Nov 2007-present) monitoring of cave air chemistry (Temperature, Relative Humidity, Barometric Pressure, Radon-222, CO2, Air flow, Wind speed and direction) in a shallow subtropical cave (Hollow Ridge) in N Florida reveals two major ventilation mechanisms: 1) ventilation driven by winds across the cave entrances, and 2) ventilation driven by density differences between atmospheric and cave air. The degree and type of ventilation strongly influence the 222Rn and CO2 of cave air, which in turn affects the timing and extent of calcite deposition in speleothems. The degree of ventilation is estimated using a cave air CO2-δ13CO2 Keeling Plot, or a simple radon deficiency model. Results show cave air has an atmospheric component ranging from 10-90%. During fall and winter, average CO2 (700 ppmv) and 222Rn (50-100 dpm/L) are lower than in spring and summer (CO2 = 1200 ppmv; 222Rn = 1000 dpm/L) due to increased winter ventilation. Decreased ventilation during the summer allows CO2 and 222Rn levels to rise. Winter daily ventilation is primarily a function of density gradients between cave air and atmospheric air, while summer daily ventilation is primarily a function of late morning NW-NE winds above the cave. Stable isotope analyses of drip water (fracture drip and pore flow drip) and aquifer water from Hollow Ridge agree with previous isotope studies of drip water at Florida Caverns State Park, 2 km to the NE. During summer, isotopic composition of pore flow drip water (δ18O -3.8 to -4.0 per mil; δD -17.3 to -20.2 per mil VSMOW) and aquifer water (δ18O -4.0 per mil; δD -18.0 to -21.1 per mil) are similar to average annual weighted isotopic composition of precipitation (δ18O -3.6 per mil) while fracture drip waters (δ18O -3 to -3.4 per mil; δD -11.9 to -14.3 per mil) likely reflect the isotopic composition of individual precipitation events. Pore flow drip waters δ18O are weakly correlated with drip rates

Avifaunal changes revealed in Quaternary deposits near Waitomo Caves, North Island, New Zealand

International Nuclear Information System (INIS)

Worthy, T.H.; Swabey, E.J.

2002-01-01

Late Pleistocene (23,000-10,000 14 C yr BP) and Holocene (10,000 14 C yr - present BP) avifaunas are described from the Henry Lambert and associated passages in Gardners Gut Cave, Waitomo Caves, North Island, New Zealand. Nine radiocarbon dates on bones and three uranium series dates on speleothems support the dating of the sites. These data are augmented by six new dates and reanalysis of the avifaunas from F1c Cave, also in the Waitomo karst. A distinctive Pleistocene avifauna characterised by the moa Euryapterix curtus and Pachyornis mappini and the North Island goose (Cnemiornis gracilis) with common associates including New Zealand coot (Fulica prisca), North Island takahe (Porphyrio mantelli), Finsch's duck (Euryanas finschi), and North Island kokako (Callaeas wilsoni) was present. The presence of kokako, saddleback (Philesturnus rufusater), and robin (Petroica longipes) in the Pleistocene deposits and the absence of grassland taxa such as pipit (Anthus noveaseelandiae) and quail (Coturnix novaezelandiae) indicate that the vegetation about Gardners Gut Cave included tall shrubland and probably lacked much grassland, even over the Last Glacial Maximum. The Holocene at Waitomo was characterised by a moa fauna dominated by Anomalopteryx didiformis, although both Euryapteryx curtus and Pachyornis mappini persisted in small numbers. The frequent occurrence of kakapo (Strigops habroptilus), weka (Gallirallus australis), and brown teal (Anas chlorotis) typifies Holocene avifaunas; Cnemiornis and Fulica are unknown from Holocene deposits in the area. (author). 45 refs., 7 figs., 8 tabs

EFFECT OF MELTER-FEED-MAKEUP ON VITRIFICATION PROCESS

International Nuclear Information System (INIS)

Kruger, A.A.; Hrma, P.R.; Schweiger, M.J.; Humrickhouse, C.J.; Moody, J.A.; Tate, R.M.; Tegrotenhuis, N.E.; Arrigoni, B.M.; Rodriguez, C.P.

2009-01-01

Increasing the rate of glass processing in the Hanford Tank Waste Treatment and Immobilization Plant (WTP) will allow shortening the life cycle of waste cleanup at the Hanford Site. While the WTP melters have approached the limit of increasing the rate of melting by enhancing the heat transfer rate from molten glass to the cold cap, a substantial improvement can still be achieved by accelerating the feed-to-glass conversion kinetics. This study investigates how the feed-to-glass conversion process responds to the feed makeup. By identifying the means of control of primary foam formation and silica grain dissolution, it provides data needed for a meaningful and economical design of large-scale experiments aimed at achieving faster melting

Minerals cave, Volcan Irazu, Costa Rica: description, mineralogy and origin

International Nuclear Information System (INIS)

Ulloa, Andres; Campos-Fernandez, Cristian S.; Rojas, Leonardo

2013-01-01

Two caves are found in the NW sector of the main crater of the Volcan Irazu at the base of the crown of a glide. The caves are located in an area of structural weakness of the massif developed in sequences of pyroclasts with hydrothermal alteration. Several explorations are organized for the recognition of the caves. The purpose has been of collecting samples and photographs for mineralogical and topographic analyses, through X-ray diffractometry. The minerals present in the samples are compared and identified by means of PDF-2 power x-ray diffraction database of the 2007 ICDD, International Center for Diffraction Data. The origin of the caves has been studied, and it is suggested to carry out other of complement studies [es

Isotopic investigations of the waters from the Movile Cave - Mangalia area

International Nuclear Information System (INIS)

Feurdean, Lucia; Feurdean, Victor

2001-01-01

As a conservative tracer in carbonate rocks deuterium was used to determine the unelucidated problems of water origin in the Movile Cave-Mangalia, which is the unique ecosystem from the world based on chemoautotrophic conditions. According to the δD values the water from Movile Cave is meteoric in origin but can not originate from local site. The groundwater from neighboring area of cave has their recharge area at high altitude and considerable distance. δD values of water samples present time variations with a distinct seasonal effect. The seasonal δD values are shifted with a half meteoric cycle vs. normal succession of seasonal maximum and minimum values. Water seems to be originated from the Prebalkan Plateau situated in the south of Dobrogea. The study indicates that the intrusion of water in the karst occurs by conduit flow and hydrostatic pressure. The geometry of conduit controls the movement of the water. The cave and the Karaoban Lake is the discharge area of two main components of groundwater: the first is coming from southwest and has isotope characteristic similar to lower altitude water (500 m) and the second is moving from southeast and has the isotope composition similar to high altitude water (>1000 m). The Movile Cave and Karaoban Lake are connected and the cave water is discharged by overflow mechanism isolating the cave from atmosphere. (authors)

Speleogenesis, geometry, and topology of caves: A quantitative study of 3D karst conduits

Science.gov (United States)

Jouves, Johan; Viseur, Sophie; Arfib, Bruno; Baudement, Cécile; Camus, Hubert; Collon, Pauline; Guglielmi, Yves

2017-12-01

Karst systems are hierarchically spatially organized three-dimensional (3D) networks of conduits behaving as drains for groundwater flow. Recently, geostatistical approaches proposed to generate karst networks from data and parameters stemming from analogous observed karst features. Other studies have qualitatively highlighted relationships between speleogenetic processes and cave patterns. However, few studies have been performed to quantitatively define these relationships. This paper reports a quantitative study of cave geometries and topologies that takes the underlying speleogenetic processes into account. In order to study the spatial organization of caves, a 3D numerical database was built from 26 caves, corresponding to 621 km of cumulative cave passages representative of the variety of karst network patterns. The database includes 3D speleological surveys for which the speleogenetic context is known, allowing the polygenic karst networks to be divided into 48 monogenic cave samples and classified into four cave patterns: vadose branchwork (VB), water-table cave (WTC), looping cave (LC), and angular maze (AM). Eight morphometric cave descriptors were calculated, four geometrical parameters (width-height ratio, tortuosity, curvature, and vertical index) and four topological ones (degree of node connectivity, α and γ graph indices, and ramification index) respectively. The results were validated by statistical analyses (Kruskal-Wallis test and PCA). The VB patterns are clearly distinct from AM ones and from a third group including WTC and LC. A quantitative database of cave morphology characteristics is provided, depending on their speleogenetic processes. These characteristics can be used to constrain and/or validate 3D geostatistical simulations. This study shows how important it is to relate the geometry and connectivity of cave networks to recharge and flow processes. Conversely, the approach developed here provides proxies to estimate the evolution of

Final Report Melter Tests With AZ-101 HLW Simulant Using A Duramelter 100 Vitrification System VSL-01R10N0-1, Rev. 1, 2/25/02

International Nuclear Information System (INIS)

Kruger, A.A.; Matlack, K.S.; Kot, W.K.; Pegg, I.L.

2011-01-01

This report provides data, analyses, and conclusions from a series of tests that were conducted at the Vitreous State Laboratory of The Catholic of America (VSL) to determine the processing rates that are achievable with AZ-101 HLW simulants and corresponding melter feeds on a DuraMelter 100 (DM100) vitrification system. One of the most critical pieces of information in determining the required size of the RPP-WTP HLW melter is the specific glass production rate in terms of the mass of glass that can be produced per unit area of melt surface per unit time. The specific glass production rate together with the waste loading (essentially, the ratio of waste-in to glass-out, which is determined from glass formulation activities) determines the melt area that is needed to achieve a given waste processing rate with due allowance for system availability. Tests conducted during Part B1 (VSL-00R2590-2) on the DM1000 vitrification system installed at the Vitreous State Laboratory of The Catholic University of America showed that, without the use of bubblers, glass production rates with AZ-101 and C-106/AY-102 simulants were significantly lower than the Project design basis rate of 0.4 MT/m 2 /d. Conversely, three-fold increases over the design basis rate were demonstrated with the use of bubblers. Furthermore, an un-bubbled control test using a replica of the melter feed used in cold commissioning tests at West Valley reproduced the rates that were observed with that feed on the WVDP production melter. More recent tests conducted on the DM1200 system, which more closely represents the present RPP-WTP design, are in general agreement with these earlier results. Screening tests conducted on the DM10 system have provided good indications of the larger-scale processing rates with bubblers (for both HL W and LAW feeds) but significantly overestimated the DM1000 un-bubbled rate observed for C-106/AY-102 melter feeds. This behavior is believed to be a consequence of the role of

Identification of Martian Cave Skylights Using the Temperature Change During Day and Night

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Jongil Jung

2014-06-01

Full Text Available Recently, cave candidates have been discovered on other planets besides the Earth, such as the Moon and Mars. When we go to other planets, caves could be possible human habitats providing natural protection from cosmic threats. In this study, seven cave candidates have been found on Pavonis Mons and Ascraeus Mons in Tharsis Montes on Mars. The cave candidates were selected using the images of the Context Camera (CTX on the Mars Reconnaissance Orbiter (MRO. The Context Camera could provide images with the high resolution of 6 meter per pixel. The diameter of the candidates ranges from 50 to 100m. Cushing et al. (2007 have analyzed the temperature change at daytime and nighttime using the Thermal Emission Imaging System (THEMIS for the sites of potential cave candidates. Similarly, we have examined the temperature change at daytime and at nighttime for seven cave candidates using the method of Cushing et al. (2007. Among those, only one candidate showed a distinct temperature change. However, we cannot verify a cave based on the temperature change only and further study is required for the improvement of this method to identify caves more clearly.

Identification of Martian Cave Skylights Using the Temperature Change During Day and Night

Science.gov (United States)

Jung, Jongil; Yi, Yu; Kim, Eojin

2014-06-01

Recently, cave candidates have been discovered on other planets besides the Earth, such as the Moon and Mars. When we go to other planets, caves could be possible human habitats providing natural protection from cosmic threats. In this study, seven cave candidates have been found on Pavonis Mons and Ascraeus Mons in Tharsis Montes on Mars. The cave candidates were selected using the images of the Context Camera (CTX) on the Mars Reconnaissance Orbiter (MRO). The Context Camera could provide images with the high resolution of 6 meter per pixel. The diameter of the candidates ranges from 50 to 100m. Cushing et al. (2007) have analyzed the temperature change at daytime and nighttime using the Thermal Emission Imaging System (THEMIS) for the sites of potential cave candidates. Similarly, we have examined the temperature change at daytime and at nighttime for seven cave candidates using the method of Cushing et al. (2007). Among those, only one candidate showed a distinct temperature change. However, we cannot verify a cave based on the temperature change only and further study is required for the improvement of this method to identify caves more clearly.

Profiling bacterial diversity in a limestone cave of the western Loess Plateau of China

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Yucheng eWu

2015-03-01

Full Text Available Bacteria and archaea sustain subsurface cave ecosystems by dominating primary production and fueling biogeochemical cyclings, despite the permanent darkness and shortage of nutrients. However, the heterogeneity and underlying mechanism of microbial diversity in caves, in particular those well connect to surface environment are largely unexplored. In this study, we examined the bacterial abundance and composition in Jinjia Cave, a small and shallow limestone cave located on the western Loess Plateau of China, by enumerating and pyrosequencing small subunit (SSU rRNA genes. The results clearly reveal the contrasting bacterial community compositions in relation to cave habitat types, i.e., rock wall deposit, aquatic sediment and sinkhole soil, which are differentially connected to the surface environment. The deposits on the cave walls were dominated by putative cave-specific bacterial lineages within the -Proteobacteria or Actinobacteria that are routinely found on cave rocks around the world. In addition, sequence identity with known functional groups suggests enrichments of chemolithotrophic bacteria potentially involved in autotrophic C fixation and inorganic N transformation on rock surfaces. By contrast, bacterial communities in aquatic sediments were more closely related to those in the overlying soils. This is consistent with the similarity in elemental composition between the cave sediment and the overlying soil, implicating the influence of mineral chemistry on cave microhabitat and bacterial composition. These findings provide compelling molecular evidence of the bacterial community heterogeneity in an East Asian cave, which might be controlled by both subsurface and surface environments.

Some deep caves in Biokovo Mountain (Croatia)

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Garasic, Mladen; Garasic, Davor

2014-05-01

The investigation of 3 caves explored more than 1000 meters in depth in the Dinaric karst area in Croatia, has been in progress for a considerable period of time. These are complex speleological features situated in the longest mountain range of the Dinaric karst, i.e. at the Northern Velebit mountain range. In fact, these caves have been studied for over two decades now. The first one is a cave system of Lukina jama (Luke's Cave) - Trojama cave, which has been investigated until the depth of 1421 meters (Jalžić, 2007; Šmida, 1993). Its total length is 3731 meters and a new expedition will soon continue to investigate this pit through speleodiving in siphons. The second greatest cave by depth is Slovačka jama (Slovak Cave), 1320 meters in depth, with cave chanals measuring 5677 meters in total length. The third greatest cave by depth is the Cave system of Velebita, reaching down to 1026 m in depth, with the chanal length of 3176 meters (Bakšić, 2006a; 2006b). However, another 3 speleological sites, which can rightly be added to those deeper than 1000 m, have recently been discovered. These are three caverns that were discovered during construction of the Sveti Ilija Tunnel that passes through Mt. Biokovo, in the Dinaric karst area. These caverns undoubtedly point to the link with the ground surface, while the rock overburden above the tunnel in the zone where the caverns were discovered ranges from 1250 and 1350 meters. Bats from the ground surface were found in the caverns and, according to measurements, they are situated in the depth from 200 and 300 meters below the tunnel level. This would mean that the depth of these newly found caves ranges from 1450 and 1650 m, when observed from the ground surface. There are several hundreds of known caves in Biokovo, and the deepest ones discovered so far are Jama Mokre noge (Wet Feet Cave) 831 m in depth, and Jama Amfora (Amphora Cave) 788 m in depth (Bockovac, 1999; Bakšić & all, 2002; Lacković & all, 2001

A JOULE-HEATED MELTER TECHNOLOGY FOR THE TREATMENT AND IMMOBILIZATION OF LOW-ACTIVITY WASTE

Energy Technology Data Exchange (ETDEWEB)

KELLY SE

2011-04-07

This report is one of four reports written to provide background information regarding immobilization technologies remaining under consideration for supplemental immobilization of Hanford's low-activity waste. This paper provides the reader a general understanding of joule-heated ceramic lined melters and their application to Hanford's low-activity waste.

Mediterranean Recluse Spider, Loxosceles rufescens (Araneae: Sicariidae from Charkhab Cave, Southern Iran

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Saber Sadeghi

2017-04-01

Full Text Available Background: The best-known dangerous spiders belong to the six genera. The genus Loxosceles or violin spiders are well known for their ability to cause skin necrosis or loxoscelism. All Loxosceles species have medical im­portance due to their necrotizing venom. The present article reports the occurrence of L. rufescens in Charkhab Cave, south of Iran (Larestan.Methods: The specimens were collected from the Charkhab Cave using handling forceps, paintbrush and aspirator and preserved in 96% ethanol.Results: Loxosceles rufescens, a medically important spider, is recorded from Charkhab Cave in Fars Province (southwest of Iran. Identification of L. rufescens was performed based on external morphology and the features of male genitalia.Conclusion: Presence of L. rufescens in south of Iran especially in a cave confirmed that this species is a widely distributed species in Iran. Therefore, cavers or cave visitors should be aware of this poisonous spider in caves.

Environmental drivers of phototrophic biofilms in an Alpine show cave (SW-Italian Alps)

International Nuclear Information System (INIS)

Piano, E.; Bona, F.; Falasco, E.; La Morgia, V.; Badino, G.; Isaia, M.

2015-01-01

The proliferation of lampenflora is a major threat for the conservation of show caves, since phototrophic organisms cause physical, chemical and aesthetic damage to speleothems. In this paper we examine the environmental factors influencing the presence and the growth of the three main photosynthetic groups composing phototrophic biofilms in the Bossea show cave (SW-Italian Alps). The presence and the primary production of cyanobacteria, diatoms and green algae were detected with BenthoTorch®, an instrument for in situ measurement of chlorophyll a concentration that has never been used before in caves. By means of different techniques of regression analysis, we highlighted the response of the three photosynthetic groups to different environmental factors. Illuminance proved to be the main factor influencing positively both the probability of the presence and the productivity of the three groups. The presence of seeping water on the substrate and the distance from the cave entrance proved to play an important role in determining patterns of colonization. By means of GIS techniques, we provide thematic maps of the cave, providing a representation of pattern of the density of the three examined photosynthetic groups within different areas of the cave. The same approach may apply to other show caves, aiming at providing suggestions for the cave management (i.e. cleaning of the cave walls and positioning of artificial lights) and reduce impact caused by tourism. - Highlights: • We used a PAM fluorimeter on autotrophic biofilms in a show cave for the first time. • We modelled the environmental factors influencing phototrophic biofilms. • Illuminance, moisture and distance from the entrance proved to be significant. • We produced thematic maps illustrating our results. • We provide suggestions for cave management

Environmental drivers of phototrophic biofilms in an Alpine show cave (SW-Italian Alps)

Energy Technology Data Exchange (ETDEWEB)

Piano, E., E-mail: elena.piano@unito.it [Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123 Turin (Italy); Bona, F.; Falasco, E. [Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123 Turin (Italy); La Morgia, V. [ISPRA, via Ca' Fornacetta, 9, 40064 Ozzano dell' Emilia (Italy); Badino, G. [Department of Physics, University of Turin, Via P. Giuria 1, 10125 Turin (Italy); Isaia, M. [Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123 Turin (Italy)

2015-12-01

The proliferation of lampenflora is a major threat for the conservation of show caves, since phototrophic organisms cause physical, chemical and aesthetic damage to speleothems. In this paper we examine the environmental factors influencing the presence and the growth of the three main photosynthetic groups composing phototrophic biofilms in the Bossea show cave (SW-Italian Alps). The presence and the primary production of cyanobacteria, diatoms and green algae were detected with BenthoTorch®, an instrument for in situ measurement of chlorophyll a concentration that has never been used before in caves. By means of different techniques of regression analysis, we highlighted the response of the three photosynthetic groups to different environmental factors. Illuminance proved to be the main factor influencing positively both the probability of the presence and the productivity of the three groups. The presence of seeping water on the substrate and the distance from the cave entrance proved to play an important role in determining patterns of colonization. By means of GIS techniques, we provide thematic maps of the cave, providing a representation of pattern of the density of the three examined photosynthetic groups within different areas of the cave. The same approach may apply to other show caves, aiming at providing suggestions for the cave management (i.e. cleaning of the cave walls and positioning of artificial lights) and reduce impact caused by tourism. - Highlights: • We used a PAM fluorimeter on autotrophic biofilms in a show cave for the first time. • We modelled the environmental factors influencing phototrophic biofilms. • Illuminance, moisture and distance from the entrance proved to be significant. • We produced thematic maps illustrating our results. • We provide suggestions for cave management.

Hurricane Impact on Seepage Water in Larga Cave, Puerto Rico

Science.gov (United States)

Vieten, Rolf; Warken, Sophie; Winter, Amos; Schröder-Ritzrau, Andrea; Scholz, Denis; Spötl, Christoph

2018-03-01

Hurricane-induced rainfall over Puerto Rico has characteristic δ18O values which are more negative than local rainfall events. Thus, hurricanes may be recorded in speleothems from Larga cave, Puerto Rico, as characteristic oxygen isotope excursions. Samples of 84 local rainfall events between 2012 and 2013 ranged from -6.2 to +0.3‰, whereas nine rainfall samples belonging to a rainband of hurricane Isaac (23-24 August 2012) ranged from -11.8 to -7.1‰. Cave monitoring covered the hurricane season of 2014 and investigated the impact of hurricane rainfall on drip water chemistry. δ18O values were measured in cumulative monthly rainwater samples above the cave. Inside the cave, δ18O values of instantaneous drip water samples were analyzed and drip rates were recorded at six drip sites. Most effective recharge appears to occur during the wet months (April-May and August-November). δ18O values of instantaneous drip water samples ranged from -3.5 to -2.4‰. In April 2014 and April 2015 some drip sites showed more negative δ18O values than the effective rainfall (-2.9‰), implying an influence of hurricane rainfall reaching the cave via stratified seepage flow months to years after the event. Speleothems from these drip sites in Larga cave have a high potential for paleotempestology studies.

Insectivorous bat reproduction and human cave visitation in Cambodia: A perfect conservation storm?

Science.gov (United States)

Lim, Thona; Cappelle, Julien; Hoem, Thavry; Furey, Neil

2018-01-01

Cave roosting bats represent an important component of Southeast Asian bat diversity and are vulnerable to human disturbance during critical reproductive periods (pregnancy, lactation and weaning). Because dramatic growth of cave tourism in recent decades has raised concerns about impacts on cave bats in the region, we assessed the reproductive phenology of two insectivorous species (Hipposideros larvatus sensu lato and Taphozous melanopogon) at three caves in Cambodia for 23 months in 2014-2016 and evaluated human visitation to these sites between 2007 and 2014. Despite the differing foraging strategies employed by the two taxa, the temporal consistency observed in proportions of pregnant, lactating and juvenile bats indicates that their major birth peaks coincide with the time of greatest cave visitation annually, particularly for domestic visitors and namely during the Cambodian new year in April. They also reflect rainfall patterns and correspond with the reproductive phenology of insectivorous cave bats in Vietnam. These findings were predictable because 1) insect biomass and thus food availability for insectivorous bats are optimal for ensuring survival of young following this period, and 2) the Khmer new year is the most significant month for religious ceremonies and thus domestic cave visitation nationally, due to the abundance of Buddhist shrines and temples in Cambodian caves. While the impact of visitor disturbance on bat population recruitment cannot be empirically assessed due to lack of historical data, it is nonetheless likely to have been considerable and raises a conservation concern. Further, because growing evidence suggests that insectivorous cave bats exhibit reproductive synchrony across continental Southeast Asia where countless cave shrines are heavily frequented during April in Theravada Buddhist countries (e.g., Myanmar, Thailand, Cambodia and Laos), our results may have wider applicability in the region. We consequently advocate for

Insectivorous bat reproduction and human cave visitation in Cambodia: A perfect conservation storm?

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Thona Lim

Full Text Available Cave roosting bats represent an important component of Southeast Asian bat diversity and are vulnerable to human disturbance during critical reproductive periods (pregnancy, lactation and weaning. Because dramatic growth of cave tourism in recent decades has raised concerns about impacts on cave bats in the region, we assessed the reproductive phenology of two insectivorous species (Hipposideros larvatus sensu lato and Taphozous melanopogon at three caves in Cambodia for 23 months in 2014-2016 and evaluated human visitation to these sites between 2007 and 2014. Despite the differing foraging strategies employed by the two taxa, the temporal consistency observed in proportions of pregnant, lactating and juvenile bats indicates that their major birth peaks coincide with the time of greatest cave visitation annually, particularly for domestic visitors and namely during the Cambodian new year in April. They also reflect rainfall patterns and correspond with the reproductive phenology of insectivorous cave bats in Vietnam. These findings were predictable because 1 insect biomass and thus food availability for insectivorous bats are optimal for ensuring survival of young following this period, and 2 the Khmer new year is the most significant month for religious ceremonies and thus domestic cave visitation nationally, due to the abundance of Buddhist shrines and temples in Cambodian caves. While the impact of visitor disturbance on bat population recruitment cannot be empirically assessed due to lack of historical data, it is nonetheless likely to have been considerable and raises a conservation concern. Further, because growing evidence suggests that insectivorous cave bats exhibit reproductive synchrony across continental Southeast Asia where countless cave shrines are heavily frequented during April in Theravada Buddhist countries (e.g., Myanmar, Thailand, Cambodia and Laos, our results may have wider applicability in the region. We consequently

Insectivorous bat reproduction and human cave visitation in Cambodia: A perfect conservation storm?

Science.gov (United States)

Cappelle, Julien; Hoem, Thavry

2018-01-01

Cave roosting bats represent an important component of Southeast Asian bat diversity and are vulnerable to human disturbance during critical reproductive periods (pregnancy, lactation and weaning). Because dramatic growth of cave tourism in recent decades has raised concerns about impacts on cave bats in the region, we assessed the reproductive phenology of two insectivorous species (Hipposideros larvatus sensu lato and Taphozous melanopogon) at three caves in Cambodia for 23 months in 2014–2016 and evaluated human visitation to these sites between 2007 and 2014. Despite the differing foraging strategies employed by the two taxa, the temporal consistency observed in proportions of pregnant, lactating and juvenile bats indicates that their major birth peaks coincide with the time of greatest cave visitation annually, particularly for domestic visitors and namely during the Cambodian new year in April. They also reflect rainfall patterns and correspond with the reproductive phenology of insectivorous cave bats in Vietnam. These findings were predictable because 1) insect biomass and thus food availability for insectivorous bats are optimal for ensuring survival of young following this period, and 2) the Khmer new year is the most significant month for religious ceremonies and thus domestic cave visitation nationally, due to the abundance of Buddhist shrines and temples in Cambodian caves. While the impact of visitor disturbance on bat population recruitment cannot be empirically assessed due to lack of historical data, it is nonetheless likely to have been considerable and raises a conservation concern. Further, because growing evidence suggests that insectivorous cave bats exhibit reproductive synchrony across continental Southeast Asia where countless cave shrines are heavily frequented during April in Theravada Buddhist countries (e.g., Myanmar, Thailand, Cambodia and Laos), our results may have wider applicability in the region. We consequently advocate for

A conservation status index, as an auxiliary tool for the management of cave environments

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Christiane Ramos Donato

2014-09-01

Full Text Available The conservation of the Speleological Heritage involves bioecological, geomorphological and anthropogenic studies, both from inside the caves and from the external environments that surround them. This study presents a method to rank caves according to their priority for conservation and restoration. Nine caves were evaluated: indicators related to the environmental impacts and the vulnerability status presented by those caves (intrinsic features and the values scored in a ‘Cave Conservation Index’ (CCI were established. We also used a rapid assessment protocol to measure cave vulnerability for prioritization of conservation/restoration actions (RAP-cr comparing natural cavities with the same lithology, due to “strictu sensu” peculiarities. Based on the protocols applied in caves of the municipality of Laranjeiras, Sergipe, Northeastern Brazil, we concluded that the present method attended to the needs for the classification of the caves into categories of conservation/restoration status, using little time and financial effort, through rapid diagnostics that facilitate the comparisons. In this perspective, the CCI can be used to indicate areas that should be protected and caves that should be prioritized to have initiated activities of conservation and restoration.

U-series dating of Paleolithic art in 11 caves in Spain.

Science.gov (United States)

Pike, A W G; Hoffmann, D L; García-Diez, M; Pettitt, P B; Alcolea, J; De Balbín, R; González-Sainz, C; de las Heras, C; Lasheras, J A; Montes, R; Zilhão, J

2012-06-15

Paleolithic cave art is an exceptional archive of early human symbolic behavior, but because obtaining reliable dates has been difficult, its chronology is still poorly understood after more than a century of study. We present uranium-series disequilibrium dates of calcite deposits overlying or underlying art found in 11 caves, including the United Nations Educational, Scientific, and Cultural Organization (UNESCO) World Heritage sites of Altamira, El Castillo, and Tito Bustillo, Spain. The results demonstrate that the tradition of decorating caves extends back at least to the Early Aurignacian period, with minimum ages of 40.8 thousand years for a red disk, 37.3 thousand years for a hand stencil, and 35.6 thousand years for a claviform-like symbol. These minimum ages reveal either that cave art was a part of the cultural repertoire of the first anatomically modern humans in Europe or that perhaps Neandertals also engaged in painting caves.

Ancient photosynthetic eukaryote biofilms in an Atacama Desert coastal cave

Science.gov (United States)

Azua-Bustos, A.; Gonzalez-Silva, C.; Mancilla, R.A.; Salas, L.; Palma, R.E.; Wynne, J.J.; McKay, C.P.; Vicuna, R.

2009-01-01

Caves offer a stable and protected environment from harsh and changing outside prevailing conditions. Hence, they represent an interesting habitat for studying life in extreme environments. Here, we report the presence of a member of the ancient eukaryote red algae Cyanidium group in a coastal cave of the hyperarid Atacama Desert. This microorganism was found to form a seemingly monospecific biofilm growing under extremely low photon flux levels. Our work suggests that this species, Cyanidium sp. Atacama, is a new member of a recently proposed novel monophyletic lineage of mesophilic "cave" Cyanidium sp., distinct from the remaining three other lineages which are all thermo-acidophilic. The cave described in this work may represent an evolutionary island for life in the midst of the Atacama Desert. ?? Springer Science + Business Media, LLC 2009.

Simultaneous caving and surface restoration system for oil shale mining

Energy Technology Data Exchange (ETDEWEB)

Allsman, P.T.

1968-10-01

A modified caving method is introduced for mining oil shale and simultaneous restoration of the land surface by return of spent shale onto the subsided area. Other methods have been designed to mine the relatively thin richer beds occurring near outcrops in the Piceance Creek Basin of NW. Colorado. Since the discovery of the much thicker beds in the N.-central part of the basin, some attention has focused on in situ and open-pit methods of recovery. Although caving has been recognized as a possible means of mining shale, most people have been skeptical of its success. This stems from the unknown and salient factors of cavability and size of broken rock with caving. Wisdom would seem to dictate that serious evaluation of the caving method be made along with the other methods.

Near Surface Geophysical Methods Applied to the Rising Star Cave System

Science.gov (United States)

Webb, S. J.; Naidoo, M.; Elliott, M. C.; Kruger, A.; Roberts, E.; Dirks, P.

2017-12-01

The Rising Star Cave system is located approximately 40 km northwest of Johannesburg in the Malmani dolomites (Chuniespoort group,Transvaal Supergroup). The cave system is extensive with 4 km of mapped passages and chambers. The Dinaledi chamber, host to the Homo Naledi fossils, is reached by following a tortuous route with squeezes as small as 20 cm. The chamber is located 30 m below surface and 80 m from the entrance. The enigmatic find of fossils from at least 15 individual hominins, without the presence of other species, led to the idea of deliberate burial. The present access route is difficult and it is unclear how early hominins were able to navigate it, prompting the suggestion of an undiscovered entrance. We are using near surface geophysical methods to investigate possible connections between the surface and the caves. Using a Geometrics Cs-vapor Walkmag, we collected preliminary ground magnetic intensity measurements over a region 300 m x 200 m, using 1 m station spacing and 10 m line spacing. The average magnetic variation along line is 200 nT. We also collected over 100 susceptibility measurements on outcropping lithologies, surface soil and cave sediments using a SM-30 susceptibility meter. The surface soil was one to two orders of magnitude higher than surrounding lithologies (average = 1.5 x 10-3 SI) and the cave sediment samples were slightly higher (average = 3.07 x 10-3 SI). We were able to collect GPR data (GSSI SIR-3000, 400 MHz) in selected spots on the cave floor with the goal of locating the cave floor beneath the sediments. Dolomites usually have low magnetic susceptibilities, but erosion products of the nearby magnetic Hospital Hill or Rooihoogte shales may have been transported into or onto the cave system. This is a likely cause of the magnetic anomalies and larger amplitude anomalies may indicate an accumulation of sediments, extending to depth. These anomalies will be further investigated using gravity to determine if there are

NEW LOCALITY OF CAVE BEAR (Ursus spelaeus Rosenmüller & Heinroth, 1794 IN BOSNIA AND HERZEGOVINA: MORPHO- ANATOMICAL CHARACTERISTICS OF CRANIAL SKELETON FOUND IN CAVE AT VRELO MOKRANJSKA MILJACKA

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Lada Lukić-Bilela

2013-10-01

Full Text Available During the investigation of the Cave at Vrelo Mokranjska Miljacka, the bone remains of the cave bear (Ursus spelaeus Rosenmüller & Heinroth, 1794 was found. This is the new Pleistocene fauna locality of this extinct species in Bosnia and Herzegovina. Almost complete cranial skeleton belongs to a young adult male. Analyzed morphometric proportions completely fit within the variation range of the Pleistocene cave bear populations in Bosnia and Herzegovina.Key words: Ursus spelaeus, skull, teeth, Cave of Vrelo Mokranjska Miljacka

Investigation of tracking systems properties in CAVE-type virtual reality systems

Science.gov (United States)

Szymaniak, Magda; Mazikowski, Adam; Meironke, Michał

2017-08-01

In recent years, many scientific and industrial centers in the world developed a virtual reality systems or laboratories. One of the most advanced solutions are Immersive 3D Visualization Lab (I3DVL), a CAVE-type (Cave Automatic Virtual Environment) laboratory. It contains two CAVE-type installations: six-screen installation arranged in a form of a cube, and four-screen installation, a simplified version of the previous one. The user feeling of "immersion" and interaction with virtual world depend on many factors, in particular on the accuracy of the tracking system of the user. In this paper properties of the tracking systems applied in I3DVL was investigated. For analysis two parameters were selected: the accuracy of the tracking system and the range of detection of markers by the tracking system in space of the CAVE. Measurements of system accuracy were performed for six-screen installation, equipped with four tracking cameras for three axes: X, Y, Z. Rotation around the Y axis was also analyzed. Measured tracking system shows good linear and rotating accuracy. The biggest issue was the range of the monitoring of markers inside the CAVE. It turned out, that the tracking system lose sight of the markers in the corners of the installation. For comparison, for a simplified version of CAVE (four-screen installation), equipped with eight tracking cameras, this problem was not occur. Obtained results will allow for improvement of cave quality.

Ancient DNA reveals differences in behaviour and sociality between brown bears and extinct cave bears.

Science.gov (United States)

Fortes, Gloria G; Grandal-d'Anglade, Aurora; Kolbe, Ben; Fernandes, Daniel; Meleg, Ioana N; García-Vázquez, Ana; Pinto-Llona, Ana C; Constantin, Silviu; de Torres, Trino J; Ortiz, Jose E; Frischauf, Christine; Rabeder, Gernot; Hofreiter, Michael; Barlow, Axel

2016-10-01

Ancient DNA studies have revolutionized the study of extinct species and populations, providing insights on phylogeny, phylogeography, admixture and demographic history. However, inferences on behaviour and sociality have been far less frequent. Here, we investigate the complete mitochondrial genomes of extinct Late Pleistocene cave bears and middle Holocene brown bears that each inhabited multiple geographically proximate caves in northern Spain. In cave bears, we find that, although most caves were occupied simultaneously, each cave almost exclusively contains a unique lineage of closely related haplotypes. This remarkable pattern suggests extreme fidelity to their birth site in cave bears, best described as homing behaviour, and that cave bears formed stable maternal social groups at least for hibernation. In contrast, brown bears do not show any strong association of mitochondrial lineage and cave, suggesting that these two closely related species differed in aspects of their behaviour and sociality. This difference is likely to have contributed to cave bear extinction, which occurred at a time in which competition for caves between bears and humans was likely intense and the ability to rapidly colonize new hibernation sites would have been crucial for the survival of a species so dependent on caves for hibernation as cave bears. Our study demonstrates the potential of ancient DNA to uncover patterns of behaviour and sociality in ancient species and populations, even those that went extinct many tens of thousands of years ago. © 2016 John Wiley & Sons Ltd.

Radon and thoron in cave dwellings (Yan'an, China)

International Nuclear Information System (INIS)

Wiegand, J.; Feige, S.; Xie Quingling; Schreiber, U.; Wieditz, K.; Wittmann, C.; Luo Xiarong

2000-01-01

222 Rn and 220 Rn concentrations were measured in cave dwellings and brick houses in the region of Yan'an (China) during summer 1997. The underground dwellings are built into Quaternary loess, and all investigated houses are founded on it. The median values of indoor 222 Rn and 220 Rn concentrations are 42 (n = 18) and 77Bq m -3 (n = 15) for brick houses and 92 (n = 23) and 215 (n = 17) Bq m -3 for cave dwellings. To classify the dwellings in respect to their cave-character, the fraction of walls having a direct contact to the loess is calculated for each dwelling. While the 222 Rn concentrations are increasing with higher fractions, the 220 Rn concentrations are not correlated with this fraction. On the other hand, due to the short half-life of 220 Rn the distance from the measuring point to the walls is negatively correlated with the 220 Rn concentration, while there is no correlation with the 222 Rn concentration. Therefore, concentric isolines of 220 Rn concentrations showing a strong gradient were detected in cave dwellings. An influence of the ventilation rate is distinct for 222 Rn but weak for 220 Rn. The effective dose rates for 222 Rn and 220 Rn and their progenies are calculated for brick houses (2.7 mSv y -1 ), cave dwellings (7.1 mSv y -1 ), and for traditional cave dwellings with a bed foundation built with loess (16.7 mSv y -1 ). These calculations are based on summer measurements only. It is expected that the true effective dose rates will be significantly higher

Diversity and biocide susceptibility of fungal assemblages dwelling in the Art Gallery of Magura Cave, Bulgaria

Czech Academy of Sciences Publication Activity Database

Mitova, M.M.; Iliev, M.; Nováková, Alena; Gorbushina, A.A.; Groudeva, V.I.; Martin-Sanchez, P.M.

2017-01-01

Roč. 46, č. 1 (2017), s. 67-80 ISSN 0392-6672 Institutional support: RVO:61388971 Keywords : fungi * cultivable microorganisms * rock-art caves Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 1.439, year: 2016

Metallurgical Evaluation of the Five-Inch Cylindrical Induction Melter

International Nuclear Information System (INIS)

Imrich, K.J.

2000-01-01

A metallurgical evaluation of the 5-inch cylindrical induction melter (CIM) vessel was performed by the Materials Technology Section to evaluate the metallurgical condition after operating for approximately 375 hours at 1400 to 1500 Degrees Celsius during a 2 year period. Results indicate that wall thinning and significant grain growth occurred in the lower portion of the conical section and the drain tube. No through-wall penetrations were found in the cylindrical and conical sections of the CIM vessel and only one leak site was identified in the drain tube. Failure of the drain tube was associated with a localized over heating and intercrystalline fracture

Measurements of seasonal and daily radon daughter concentration fluctuations in National Park Service caves

International Nuclear Information System (INIS)

Yarborough, K.A.

1977-01-01

The National Park Service (NPS) is studying levels of airborne alpha radiation from radon and thoron in all NPS administered caves in which tours for visitors are regularly conducted. The NPS research has the dual but complementary objectives of safeguarding health at the NPS administered caves, and to develop data on alpha radiation levels and on natural airflows in NPS caves. The results reported here for NPS caves describe concepts hypothesized for the objectives. In addition the data can be used by various agencies to clarify health standards for exposures to low airborne alpha radiation levels in cave environments. These results show daily and seasonal trends and the influence of natural ventilation by air circulation for each cave investigated

Cure from the cave: volcanic cave actinomycetes and their potential in drug discovery

Directory of Open Access Journals (Sweden)

Cheeptham N.

2013-01-01

Full Text Available Volcanic caves have been little studied for their potential as sources of novel microbial species and bioactive compounds with new scaffolds. We present the f irst study of volcanic cave microbiology from Canada and suggest that this habitat has great potential for the isolation of novel bioactive substances. Sample locat ions were plot ted on a contour map that was compiled in ArcView 3.2. Over 400 bacterial isolates were obtained from the Helmcken Falls cave in Wells Gray Provincial Park, British Columbia. From our preliminary screen, of 400 isolates tested, 1% showed activity against extended spectrum ß-lactamase E. coli, 1.75% against Escherichia coli, 2.25% against Acinetobacter baumannii, and 26.50% against Klebsiella pneumoniae. In addition, 10.25% showed activity against Micrococcus luteus, 2% against methicillin resistant Staphylococcus aureus, 9.25% against Mycobacterium smegmatis, 6.25% Pseudomonas aeruginosa and 7.5% against Candida albicans. Chemical and physical characteristics of three rock wall samples were studied using scanning electron microscopy and f lame atomic absorption spectrometry. Calcium (Ca, iron (Fe, and aluminum (Al were the most abundant components while magnesium (Mg, sodium (Na, arsenic (As, lead (Pb, chromium (Cr, and barium (Ba were second most abundant with cadmium (Cd and potassium (K were the least abundant in our samples. Scanning electron microscopy (SEM showed the presence of microscopic life forms in all three rock wall samples. 16S rRNA gene sequencing of 82 isolates revealed that 65 (79.3% of the strains belong to the Streptomyces genus and 5 (6.1% were members of Bacillus, Pseudomonas, Nocardia and Erwinia genera. Interestingly, twelve (14.6% of the 16S rRNA sequences showed similarity to unidentif ied ribosomal RNA sequences in the library databases, the sequences of these isolates need to be further investigated using the EzTaxon-e database (http://eztaxon-e. ezbiocloud.net/ to determine whether

Silicate Based Glass Formulations for Immobilization of U.S. Defense Wastes Using Cold Crucible Induction Melters

Energy Technology Data Exchange (ETDEWEB)

Smith, Gary L.; Kim, Dong-Sang; Schweiger, Michael J.; Marra, James C.; Lang, Jesse B.; Crum, Jarrod V.; Crawford, Charles L.; Vienna, John D.

2014-05-22

The cold crucible induction melter (CCIM) is an alternative technology to the currently deployed liquid-fed, ceramic-lined, Joule-heated melter for immobilizing of U.S. tank waste generated from defense related reprocessing. In order to accurately evaluate the potential benefits of deploying a CCIM, glasses must be developed specifically for that melting technology. Related glass formulation efforts have been conducted since the 1990s including a recent study that is first documented in this report. The purpose of this report is to summarize the silicate base glass formulation efforts for CCIM testing of U.S. tank wastes. Summaries of phosphate based glass formulation and phosphate and silicate based CCIM demonstration tests are reported separately (Day and Ray 2013 and Marra 2013, respectively). Combined these three reports summarize the current state of knowledge related to waste form development and process testing of CCIM technology for U.S. tank wastes.

Observations on the Cave-Associated Beetles (Coleoptera of Nova Scotia, Canada

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Moseley M.

2009-07-01

Full Text Available The cave-associated invertebrates of Nova Scotia constitute a fauna at a very early stage of post-glacial recolonization. TheColeoptera are characterized by low species diversity. A staphylinid Quedius spelaeus spelaeus, a predator, is the only regularlyencountered beetle. Ten other terrestrial species registered from cave environments in the province are collected infrequently. Theyinclude three other rove-beetles: Brathinus nitidus, Gennadota canadensis and Atheta annexa. The latter two together with Catopsgratiosus (Leiodidae constitute a small group of cave-associated beetles found in decompositional situations. Quedius s. spelaeusand a small suite of other guanophiles live in accumulations of porcupine dung: Agolinus leopardus (Scarabaeidae, Corticariaserrata (Latrididae, and Acrotrichis castanea (Ptilidae. Two adventive weevils Otiorhynchus ligneus and Barypeithes pellucidus(Curculionidae collected in shallow cave passages are seasonal transients; Dermestes lardarius (Dermestidae, recorded fromone cave, was probably an accidental (stray. Five of the terrestrial beetles are adventive Palaearctic species. Aquatic beetles arecollected infrequently. Four taxa have been recorded: Agabus larsoni (Dytiscidae may be habitual in regional caves; another Agabussp. (probably semivittatus, Dytiscus sp. (Dytiscidae, and Crenitis digesta (Hydrophilidae are accidentals. The distribution andecology of recorded species are discussed, and attention is drawn to the association of beetles found in a Nova Scotia “ice cave”.

Studies of condensation/evaporation processes in the Glowworm Cave, New Zealand

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de Freitas Chris R.

2006-07-01

Full Text Available The condensation/evaporation process is important in caves, especially in tourist caves where there is carbon dioxide enriched air caused by visitors. The cycle of condensation and evaporation of condensate is believed to enhance condensation corrosion. The problem is condensation is difficult to measure. This study addresses the problem and reports on a method for measuring and modelling condensation rates in a limestone cave. Electronic sensors for measuring condensation and evaporation of the condensate as part of a single continuous process of water vapour flux are tested and used to collect 12 months of data. The study site is the Glowworm tourist cave in New Zealand. The work describes an explanatory model of processes leading to condensation using data based on measurements of condensation and evaporation as part of a single continuous process of water vapour flux. The results show that the model works well. However, one of the most important messages from the research reported here is the introduction of the condensation sensor. The results show that condensation in caves can actually be measured and monitored, virtually in real time. In conjunction with the recent developments in data logging equipment, this opens exciting perspectives in cave climate studies, and, more generally, in hydrogeological studies in karst terrains.

Chemical Ecology of Cave-Dwelling Millipedes: Defensive Secretions of the Typhloiulini (Diplopoda, Julida, Julidae).

Science.gov (United States)

Makarov, Slobodan E; Bodner, Michaela; Reineke, Doris; Vujisić, Ljubodrag V; Todosijević, Marina M; Antić, Dragan Ž; Vagalinski, Boyan; Lučić, Luka R; Mitić, Bojan M; Mitov, Plamen; Anđelković, Boban D; Lucić, Sofija Pavković; Vajs, Vlatka; Tomić, Vladimir T; Raspotnig, Günther

2017-04-01

Cave animals live under highly constant ecological conditions and in permanent darkness, and many evolutionary adaptations of cave-dwellers have been triggered by their specific environment. A similar "cave effect" leading to pronounced chemical interactions under such conditions may be assumed, but the chemoecology of troglobionts is mostly unknown. We investigated the defensive chemistry of a largely cave-dwelling julid group, the controversial tribe "Typhloiulini", and we included some cave-dwelling and some endogean representatives. While chemical defense in juliform diplopods is known to be highly uniform, and mainly based on methyl- and methoxy-substituted benzoquinones, the defensive secretions of typhloiulines contained ethyl-benzoquinones and related compounds. Interestingly, ethyl-benzoquinones were found in some, but not all cave-dwelling typhloiulines, and some non-cave dwellers also contained these compounds. On the other hand, ethyl-benzoquinones were not detected in troglobiont nor in endogean typhloiuline outgroups. In order to explain the taxonomic pattern of ethyl-benzoquinone occurrence, and to unravel whether a cave-effect triggered ethyl-benzoquinone evolution, we classed the "Typhloiulini" investigated here within a phylogenetic framework of julid taxa, and traced the evolutionary history of ethyl-benzoquinones in typhloiulines in relation to cave-dwelling. The results indicated a cave-independent evolution of ethyl-substituted benzoquinones, indicating the absence of a "cave effect" on the secretions of troglobiont Typhloiulini. Ethyl-benzoquinones probably evolved early in an epi- or endogean ancestor of a clade including several, but not all Typhloiulus (basically comprising a taxonomic entity known as "Typhloiulus sensu stricto") and Serboiulus. Ethyl-benzoquinones are proposed as novel and valuable chemical characters for julid systematics.

The integrated melter off-gas treatment systems at the West Valley Demonstration Project

International Nuclear Information System (INIS)

Vance, R.F.

1991-12-01

The West Valley Demonstration project was established by an act of Congress in 1980 to solidify the high level radioactive liquid wastes produced from operation of the Western New York Nuclear Services Center from 1966 to 1972. The waste will be solidified as borosilicate glass. This report describes the functions, the controlling design criteria, and the resulting design of the melter off-gas treatment systems

Main karst and caves of Switzerland; El karst y las cuevas mas importantes de Suiza

Energy Technology Data Exchange (ETDEWEB)

Jeannin, P. Y.

2016-07-01

This paper presents an overview of the main karst areas and cave systems in Switzerland. The first part encloses descriptions of the main geological units that hold karst and caves in the country and summarizes a brief history of research and protection of the cave environments. The second part presents three regions enclosing large cave systems. Two regions in the Alps enclose some of the largest limestone caves in Europe: Siebenhengste (Siebenhengste cave system with ∼160 km and Barenschacht with 70 km) and Bodmeren-Silberen (Holloch cave system with 200 km and Silberen System with 39 km). These systems are also among the deepest with depths ranging between 880 and 1340 m. The third example is from the Jura Mountains (northern Switzerland). (Author)

Radiocarbon intercomparison program for Chauvet Cave

International Nuclear Information System (INIS)

Cuzange, M.T.; Delque-Kolic, E.; Oberlin, C.; Goslar, T.; Grootes, P.M.; Nadeau, M.J.; Higham, T.; Ramsey, C.B.; Kaltnecker, E.; Paterne, M.; Valladas, H.; Van der Plicht, J.; Van der Plicht, J.; Clottes, J.; Geneste, J.M.

2007-01-01

We present the first results of an accelerator mass spectrometry (AMS) radiocarbon intercomparison program on 3 different charcoal samples collected in one of the hearths of the Megaceros gallery of Chauvet Cave (Ardeche, France). This cave, rich in parietal decoration, is important for the study of the appearance and evolution of prehistoric art because certain drawings have been 14 C dated to the Aurignacian period at the beginning of the Upper Paleolithic. The new dates indicate an age of about 32,000 BP, which is consistent with this attribution and in agreement with the results from the same sector of the cave measured previously at the Laboratoire des Sciences du Climat et de l'Environnement (LSCE). Six laboratories were involved in the intercomparison. Samples were measured in 4 AMS facilities: Center for Isotope Research, Groningen University, the Netherlands; the Oxford Radiocarbon Accelerator Unit, UK; the Centre de datation par le carbone 14, Univ. Claude Bernard Lyon 1, France (measured by AMS facilities of Poznan University, Poland); and the LSCE, UMR CEA-CNRS-UVSQ, France (measured by the Leibniz-Labor of Christian-Albrechts-Universitat Kiel, Germany). (authors)

Characterization and management trends of negative and positive impacts of tourism in show caves

Directory of Open Access Journals (Sweden)

Heros Augusto Santos Lobo

2015-08-01

Full Text Available Caves are one of the most fragile environments on Earth ’s surface, in function of physical, atmospheric and biological specificities. The natural characteristics associated with cultural aspects of local people are the reasons to tourist potential of caves. However, the tourist use of caves can generate negative impacts on the environment. This consequence happens when inappropriate procedures of planning and management of tourism are used. Negative impacts are described in this review, as also indications of management techniques to avoid, decrease or eliminate the negative consequences of tourism in caves. Positive impacts are also presented, in order to achieve a sustainable tourism in show caves. The conclusion argues that the negative impacts should not be considered as impediments to tourism in caves. It is important to know these impacts and use it as a key to get previous answers which allow to raise the sustainability of show caves.

Pisgah Lava Cave Communication Test: Science Case Study for the Networked Constellations Initiative

Science.gov (United States)

Belov, K.; Ellison, D.; Fraeman, A.

2017-01-01