Methodology for performing measurements to release material from radiological control

International Nuclear Information System (INIS)

Durham, J.S.; Gardner, D.L.

1993-09-01

This report describes the existing and proposed methodologies for performing measurements of contamination prior to releasing material for uncontrolled use at the Hanford Site. The technical basis for the proposed methodology, a modification to the existing contamination survey protocol, is also described. The modified methodology, which includes a large-area swipe followed by a statistical survey, can be used to survey material that is unlikely to be contaminated for release to controlled and uncontrolled areas. The material evaluation procedure that is used to determine the likelihood of contamination is also described

Worker exposures from recycling surface contaminated radioactive scrap metal

International Nuclear Information System (INIS)

Kluk, A.; Phillips, J.W.; Culp, J.

1996-01-01

Current DOE policy permits release from DOE control of real property with residual levels of surficial radioactive contamination if the contamination is below approved guidelines. If the material contains contamination that is evenly distributed throughout its volume (referred to as volumetric contamination), then Departmental approval for release must be obtained in advance. Several DOE sites presently recycle surface contaminated metal, although the quantities are small relative to the quantities of metal processed by typical mini-mills, hence the potential radiation exposures to mill workers from processing DOE metals and the public from the processed metal are at present also a very small fraction of their potential value. The exposures calculated in this analysis are based on 100% of the scrap metal being processed at the maximum contamination levels and are therefore assumed to be maximum values and not likely to occur in actual practice. This paper examines the relationship between the surface contamination limits established under DOE Order 5400.5, open-quotes Radiation Protection of the Public and the Environment,close quotes and radiation exposures to workers involved in the scrap metal recycling process. The analysis is limited to surficial contamination at or below the guideline levels established in DOE Order 5400.5 at the time of release. Workers involved in the melting and subsequent fabrication of products are not considered radiation workers (no requirements for monitoring) and must be considered members of the public. The majority of the exposures calculated in this analysis range from tenths of a millirem per year (mrem/yr) to less than 5 mrem/yr. The incremental risk of cancer associated with these exposures ranges from 10 -8 cancers per year to 10 -6 cancers per year

use of the RESRAD-BUILD code to calculate building surface contamination limits

International Nuclear Information System (INIS)

Faillace, E.R.; LePoire, D.; Yu, C.

1996-01-01

Surface contamination limits in buildings were calculated for 226 Ra, 230 Th, 232 Th, and natural uranium on the basis of 1 mSv y -1 (100 mrem y -1 ) dose limit. The RESRAD-BUILD computer code was used to calculate these limits for two scenarios: building occupancy and building renovation. RESRAD-BUILD is a pathway analysis model designed to evaluate the potential radiological dose incurred by individuals working or living inside a building contaminated with radioactive material. Six exposure pathways are considered in the RESRAD-BUILD code: (1) external exposure directly from the source; (2) external exposure from materials deposited on the floor; (3) external exposure due to air submersion; (4) inhalation of airborne radioactive particles; (5) inhalation of aerosol indoor radon progeny; and (6) inadvertent ingestion of radioactive material, either directly from the sources or from materials deposited on the surfaces. The code models point, line, area, and volume sources and calculates the effects of radiation shielding, building ventilation, and ingrowth of radioactive decay products. A sensitivity analysis was performed to determine how variations in input parameters would affect the surface contamination limits. In most cases considered, inhalation of airborne radioactive particles was the primary exposure pathway. However, the direct external exposure contribution from surfaces contaminated with 226 Ra was in some cases the dominant pathway for building occupancy depending on the room size, ventilation rates, and surface release fractions. The surface contamination limits are most restrictive for 232 Th, followed by 230 Th, natural uranium, and 226 Ra. The results are compared with the surface contamination limits in the Nuclear Regulatory Commission's Regulatory Guide 1.86, which are most restrictive for 226 Ra and 230 Th, followed by 232 Th, and are least restrictive for natural uranium

Prevention and mitigation of groundwater contamination from radioactive releases

International Nuclear Information System (INIS)

1988-10-01

This document gives basic information on potential pathways and mechanisms, by which radioactive materials from releases can reach man, and on modelling considerations to predict the behaviour of radioactive materials in the ground. The main objective is to present an overview of existing techniques for preventing the offsite releases of contaminants into the groundwater systems and techniques for mitigation of effects of such releases should they occur. The recommended techniques are fully applicable to any hazardous materials, such as organic liquids, and toxic materials or otherwise dangerous materials, the presence of which in the accessible biosphere can represent health risks as well as economic losses to the general public. 11 refs, 2 figs, 8 tabs

Methods for removing contaminant matter from a porous material

Science.gov (United States)

Fox, Robert V [Idaho Falls, ID; Avci, Recep [Bozeman, MT; Groenewold, Gary S [Idaho Falls, ID

2010-11-16

Methods of removing contaminant matter from porous materials include applying a polymer material to a contaminated surface, irradiating the contaminated surface to cause redistribution of contaminant matter, and removing at least a portion of the polymer material from the surface. Systems for decontaminating a contaminated structure comprising porous material include a radiation device configured to emit electromagnetic radiation toward a surface of a structure, and at least one spray device configured to apply a capture material onto the surface of the structure. Polymer materials that can be used in such methods and systems include polyphosphazine-based polymer materials having polyphosphazine backbone segments and side chain groups that include selected functional groups. The selected functional groups may include iminos, oximes, carboxylates, sulfonates, .beta.-diketones, phosphine sulfides, phosphates, phosphites, phosphonates, phosphinates, phosphine oxides, monothio phosphinic acids, and dithio phosphinic acids.

Surface soil contamination standards

International Nuclear Information System (INIS)

Boothe, G.F.

1979-01-01

The purpose of this document is to define surface soil contamination limits for radioactive materials below which posting, restrictions and environmental controls are not necessary in order to protect personnel and the environment. The standards can also be used to determine if solid waste or other material is contaminated relative to disposal requirements. The derivation of the standards is given

A Review of Removable Surface Contamination on Radioactive Materials Transportation Containers

Energy Technology Data Exchange (ETDEWEB)

Kennedy, Jr, W. E.; Watson, E. C.; Murphy, D. W.; Harrer, B. J.; Harty, R.; Aldrich, J. M.

1981-05-01

This report contains the results of a study sponsored by the U.S. Nuclear Regulatory Commission (NRC) of removable surface contamination on radioactive materials transportation containers. The purpose of the study is to provide information to the NRC during their review of existing regulations. Data was obtained from both industry and literature on three major topics: 1) radiation doses, 2) economic costs, and 3) contamination frequencies. Containers for four categories of radioactive materials are considered including radiopharmaceuticals, industrial sources, nuclear fuel cycle materials, and low-level radioactive waste. Assumptions made in this study use current information to obtain realistic yet conservative estimates of radiation dose and economic costs. Collective and individual radiation doses are presented for each container category on a per container basis. Total doses, to workers and the public, are also presented for spent fuel cask and low-level waste drum decontamination. Estimates of the additional economic costs incurred by lowering current limits by factors of 10 and 100 are presented. Current contamination levels for each category of container are estimated from the data collected. The information contained in this report is designed to be useful to the NRC in preparing their recommendations for new regulations.

Derived surface contamination limits for the uranium mining and milling industry

International Nuclear Information System (INIS)

Ching, S.H.

1984-10-01

Derived Surface Contamination Limits (DSCL) are proposed for the control of surface contamination at the work place for the uranium mining and milling industry. They have been derived by a method incorporating recent ICRP recommendations and consideration of the radiation exposure pathways of ingestion, inhalation and external irradiation of the basal layer of skin. A generalized DSCL of 10 5 Bq/m 2 of beta activity is recommended for all contaminants likely to be found in uranium mine and mill workplaces except for fresh uranium concentrates. In the latter case, the DSCL is expressed in terms of alpha activity because the ratio of beta to alpha activities for fresh uranium concentrates is variable; the beta activity increases with the ingrowth of U-238 daughter products (Th-234 and Pa-234m) until secular equilibrium is re-established in about six months. A surface contamination limit of 10 4 Bq/m 2 of beta activity is proposed for the release of non-porous materials and equipment with no detectable loose contamination to the public domain

Contribution of the surface contamination of uranium-materials on the quantitative analysis results by electron probe microbeam analysis

International Nuclear Information System (INIS)

Bonino, O.; Fournier, C.; Fucili, C.; Dugne, O.; Merlet, C.

2000-01-01

The analytical testing of uranium materials is necessary for quality research and development in nuclear industry applications (enrichment, safety studies, fuel, etc). Electron Probe Microbeam Analysis Wavelength Dispersive Spectrometry (EPMA-WDS) is a dependable non-destructive analytical technology. The characteristic X-ray signal is measured to identify and quantify the sample components, and the analyzed volume is about one micron cube. The surface contamination of uranium materials modifies and contributes to the quantitative analysis results of EPMA-WDS. This contribution is not representative of the bulk. A thin oxidized layer appears in the first instants after preparation (burnishing, cleaning) as well as a carbon contamination layer, due to metallographic preparation and carbon cracking under the impact of the electron probe. Several analytical difficulties subsequently arise, including an overlapping line between the carbon Ka ray and the Uranium U NIVOVI ray. Sensitivity and accuracy of the quantification of light elements like carbon and oxygen are also reduced by the presence of uranium. The aim of this study was to improve the accuracy of quantitative analysis on uranium materials by EPMA-WDS by taking account of the contribution of surface contamination. The first part of this paper is devoted to the study of the contaminated surface of the uranium materials U, UFe 2 and U 6 Fe a few hours after preparation. These oxidation conditions are selected so as to reproduce the same contamination surfaces occurring in microprobe analytical conditions. Surface characterization techniques were SIMS and Auger spectroscopy. The contaminated surfaces are shown. They consist of successive layers: a carbon layer, an oxidized iron layer, followed by an iron depletion layer (only in UFe 2 and U 6 Fe), and a ternary oxide layer (U-Fe-O for UFe 2 et U 6 Fe and UO 2+x for uranium). The second part of the paper addresses the estimation of the errors in quantitative

Environmental contamination from a ground-level release of fission products

International Nuclear Information System (INIS)

Stupka, R.C.; Kephart, G.S.; Rittmann, P.D.

1986-08-01

On January 11, 1985, a ground-level release of fission products, primarily 90 Sr, occurred at the Hanford Site in southeastern Washington State. The release was detected during routine surveys and the majority of the contamination was confined to the immediate area where the release occurred. Response to the incident was complicated by a strong inversion that resulted in a buildup of 222 Rn daughter products on environmental air samples and outdoor surfaces. The cause of the release appears to have been the operation of a transfer jet that inadvertently pressurized an unblanked line leading to the 241-C-151 Diversion Box. A buildup of pressure inside the diversion box forced contaminated air through gaps in the diversion box cover blocks resulting in an unmonitored, short duration release to the environment. The source term was estimated using data obtained from environmental air samplers. The ground deposition speed was calculated using the integrated exposure (air samples) and surface contamination levels obtained from recently fallen snow. The total release was estimated to be 1.4 Ci 90 Sr and 0.02 Ci 137 Cs. Based on this source term, the maximum 50-yr dose commitment to onsite pesonnel was 50 mrem whole body and 600 mrem bone. No detectable internal deposition occurred during the incident and corrective action which followed; this was probably due to several factors: (1) prompt detection of the release; (2) localized contamination control; (3) excellent personnel protection practices; and (4) the protection offered by building ventilation systems. The theoretical maximum offsite individual would receive a potential 1-yr dose commitment of 0.01 mrem whole body and 0.2 mrem bone from this incident. The potential 50-yr dose commitment would be 0.13 mrem whole body and 2.0 mrem bone. In actuality, neither onsite or offsite individuals would be expected to receive even these small dose commitments

Surface contamination technology in decommissioning of nuclear fuel cycle

International Nuclear Information System (INIS)

Ishiguro, Hideharu

2012-01-01

Surface contamination measurement is the most basic technology in radiation control of the nuclear and radiation facilities. Loose surface contamination causes internal exposure through airborne contamination. Surface contamination measurement is recently more important in the waste management such as confirmation of decontamination factor, contamination survey of carried-out materials from radioactive control area, and application of clearance level. This report describes the base of surface contamination standards, meaning of contamination in decommissioning, relationship between clearance level and surface contamination, and current technology of surface contamination measurement. (author)

Correlation between Ni base alloys surface conditioning and cation release mitigation in primary coolant

Energy Technology Data Exchange (ETDEWEB)

Clauzel, M.; Guillodo, M.; Foucault, M. [AREVA NP SAS, Technical Centre, Le Creusot (France); Engler, N.; Chahma, F.; Brun, C. [AREVA NP SAS, Chemistry and Radiochemistry Group, Paris La Defense (France)

2010-07-01

The mastering of the reactor coolant system radioactive contamination is a real stake of performance for operating plants and new builds. The reduction of activated corrosion products deposited on RCS surfaces allows minimizing the global dose integrated by workers which supports the ALARA approach. Moreover, the contamination mastering limits the volumic activities in the primary coolant and thus optimizes the reactor shutdown duration and environment releases. The main contamination sources on PWR are due to Co-60 and Co-58 nuclides which come respectively Co-59 and Ni-58, naturally present in alloys used in the RCS. Co is naturally present as an impurity in alloys or as the main component of hardfacing materials (Stellites™). Ni is released mainly by SG tubes which represent the most important surface of the RCS. PWR steam generators (SG), due to the huge wetted surface are the main source of corrosion products release in the primary coolant circuit. As corrosion products may be transported throughout the whole circuit, activated in the core, and redeposited all over circuit surfaces, resulting in an increase of activity buildup, it is of primary importance to gain a better understanding of phenomenon leading to corrosion product release from SG tubes before setting up mitigation measures. Previous studies have shown that SG tubing made of the same material had different release rates. To find the origin of these discrepancies, investigations have been performed on tubes at the as-received state and after exposure to a nominal primary chemistry in titanium recirculating loop. These investigations highlighted the existence of a correlation between the inner surface metallurgical properties and the release of corrosion products in primary coolant. Oxide films formed in nominal primary chemistry are always protective, their morphology and their composition depending strongly on the geometrical, metallurgical and physico-chemical state of the surface on which they

Influence of the conditional release of the materials with very low level of radioactivity on the environment - 59132

International Nuclear Information System (INIS)

Prvakova, Slavka; Mrskova, Adela; Pritrsky, Jozef

2012-01-01

Significant amount of solid materials (metals, non-metals, building structures) that could be contaminated or activated is produced during operation and especially decommissioning of nuclear power plants. Considerable fraction of these materials has level of radioactivity close to the radiological limits allowing its safe release into the environment thereby could be potentially recycled within the special constructions, as for example tunnels, roads or bridges. If the requirements of legislation on the radiological limits for handling such material and long-term safety of the constructions are met, contaminated material can be incorporated in the form of recycled concrete, remelted steel, etc. The paper presents implementation of the IAEA and EC recommendations into the form of detailed analytical approaches with the aim to develop integrated scenarios and to analyse long-term influence of the conditional release of the material with very low level of radioactivity on the environment. Further, an estimation of the key input parameters characteristic for the specific conditions of Slovak case in order to fulfil the radiological limits according to the Slovak legislation is included. Analysed integrated scenarios represent surface or underground civil construction with radionuclides released directly into the geosphere and transported by a groundwater flow to the biosphere. The migration of radionuclides is modelled in the near-surface conditions with the advection as a dominant transport mechanism. Computer code GoldSim is used to evaluate the long-term safety assessment of the conditionally released material on the environment. (authors)

Residence time of contaminants released in surface coal mines -- a wind-tunnel study

Energy Technology Data Exchange (ETDEWEB)

Thompson, R.S. [Environmental Protection Agency, Research Triangle Park, NC (United States)

1994-12-31

Surface coal mining operations (blasting, shoveling, loading, trucking, etc.) are sources of airborne particles. The 1990 Clean Air Act Amendments direct the EPA to analyze the accuracy of the Industrial Source Complex model and the AP-42 emission factors, and to make revisions as may be necessary to eliminate any significant over-prediction of air concentration of fugitive particles from surface coal mines. A wind-tunnel study was performed at the US EPA`s Fluid Modeling Facility to investigate dispersion from surface coal mines in support of the dispersion modeling activities. Described here is the portion of the study directed at determining the residence time that material released near the floor of a mine will stay within the mine.

Potential airborne release from soil-working operations in a contaminated area

International Nuclear Information System (INIS)

Sutter, S.L.

1980-08-01

Experiments were performed to provide an indication of how much material could be made airborne during soil-working operations in a contaminated area. Approximately 50 kg of contaminated soil were collected, dried, and mixed, and particle size distribution and 137 Cs content were characterized. In four experiments performed in a 2 ft x 2 ft wind tunnel at the Radioactive Aerosol Release Test Facility, soil was pumped into an airstream moving at 3.2, 10.4, 15.2, and 20 mph. These experiments were designed to maximize airborne releases by fluidizing the soil as it was pumped into the wind tunnel. Thus the airborne releases should represent upper limit values for soil-working operations. Airborne concentration and particle size samples were collected and all of the material deposited downstream was collected to calculate a mass balance. The fraction airborne was calculated using these measurements

Molding method of buffer material for underground disposal of radiation-contaminated material, and molded buffer material

International Nuclear Information System (INIS)

Akasaka, Hidenari; Shimura, Satoshi; Kawakami, Susumu; Ninomiya, Nobuo; Yamagata, Junji; Asano, Eiichi

1995-01-01

Upon molding of a buffer material to be used upon burying a vessel containing radiation-contaminated materials in a sealed state, a powdery buffer material to be molded such as bentonite is disposed at the periphery of a mandrel having a cylindrical portion somewhat larger than contaminate container to be subjected to underground disposal. In addition, it is subjected to integration-molding such as cold isotropic press with a plastic film being disposed therearound, to form a molding product at high density. The molding product is released and taken out with the plastic film being disposed thereon. Releasability from an elastic mold is improved by the presence of the plastic film. In addition, if it is stored or transported while having the plastic film being disposed thereon, swelling of the buffer material due to water absorption or moisture absorption can be suppressed. (T.M.)

Modeling of laser damage initiated by surface contamination

International Nuclear Information System (INIS)

Feit, M.D.; Rubenchik, A.M.; Faux, D.R.; Riddle, R.A.; Shapiro, A.; Eder, D.C.; Penetrante, B.M.; Milam, D.; Genin, F.Y.; Kozlowski, M.R.

1996-11-01

The authors are engaged in a comprehensive effort to understand and model the initiation and growth of laser damage initiated by surface contaminants. This includes, for example, the initial absorption by the contaminant, heating and plasma generation, pressure and thermal loading of the transparent substrate, and subsequent shockwave propagation, 'splashing' of molten material and possible spallation, optical propagation and scattering, and treatment of material fracture. The integration use of large radiation hydrodynamics codes, optical propagation codes and material strength codes enables a comprehensive view of the damage process The following picture of surface contaminant initiated laser damage is emerging from our simulations

Fluoride-releasing restorative materials and secondary caries.

Science.gov (United States)

Hicks, John; Garcia-Godoy, Franklin; Donly, Kevin; Flaitz, Catherine

2003-03-01

Secondary caries is responsible for 60 percent of all replacement restorations in the typical dental practice. Risk factors for secondary caries are similar to those for primary caries development. Unfortunately, it is not possible to accurately predict which patients are at risk for restoration failure. During the past several decades, fluoride-releasing dental materials have become a part of the dentist's armamentarium. Considerable fluoride is released during the setting reaction and for periods up to eight years following restoration placement. This released fluoride is readily taken up by the cavosurface tooth structure, as well as the enamel and root surfaces adjacent to the restoration. Resistance against caries along the cavosurface and the adjacent smooth surface has been shown in both in vitro and in vivo studies. Fluoride-releasing dental materials provide for improved resistance against primary and secondary caries in coronal and root surfaces. Plaque and salivary fluoride levels are elevated to a level that facilitates remineralization. In addition, the fluoride released to dental plaque adversely affects the growth of lactobacilli and mutans streptococci by interference with bacterial enzyme systems. Fluoride recharging of these dental materials is readily achieved with fluoridated toothpastes, fluoride mouthrinses, and other sources of topical fluoride. This allows fluoride-releasing dental materials to act as intraoral fluoride reservoirs. The improvement in the properties of dental materials with the ability to release fluoride has improved dramatically in the past decade, and it is anticipated that in the near future the vast majority of restorative procedures will employ fluoride-releasing dental materials as bonding agents, cavity liners, luting agents, adhesives for orthodontic brackets, and definitive restoratives.

Contaminant Release from Residual Waste in Closed Single-Shell Tanks and Other Waste Forms Associated with the Tanks

International Nuclear Information System (INIS)

Deutsch, William J.

2008-01-01

This chapter describes the release of contaminants from the various waste forms that are anticipated to be associated with closure of the single-shell tanks. These waste forms include residual sludge or saltcake that will remain in the tanks after waste retrieval. Other waste forms include engineered glass and cementitious materials as well as contaminated soil impacted by previous tank leaks. This chapter also describes laboratory testing to quantify contaminant release and how the release data are used in performance/risk assessments for the tank waste management units and the onsite waste disposal facilities. The chapter ends with a discussion of the surprises and lessons learned to date from the testing of waste materials and the development of contaminant release models

Materials SIG quantification and characterization of surface contaminants

Science.gov (United States)

Crutcher, E. Russ

1992-01-01

When LDEF entered orbit its cleanliness was approximately a MIL-STD-1246B Level 2000C. Its burden of contaminants included particles from every part of its history including a relatively small contribution from the shuttle bay itself. Although this satellite was far from what is normally considered clean in the aerospace industry, contaminating events in orbit and from processing after recovery were easily detected. The molecular contaminants carried into orbit were dwarfed by the heavy deposition of UV polymerized films from outgassing urethane paints and silicone based materials. Impacts by relatively small objects in orbit could create particulate contaminants that easily dominated the particle counts within a centimeter of the impact site. During the recovery activities LDEF was 'sprayed' with a liquid high in organics and water soluble salts. With reentry turbulence, vibration, and gravitational loading particulate contaminants were redistributed about LDEF and the shuttle bay.

Development of radioactive surface contamination monitor

International Nuclear Information System (INIS)

Hashimoto, Tadao; Hasegawa, Toru; Fukumoto, Keisuke; Ooki, Yasushi

2008-01-01

In the radiation facilities such as nuclear power plants, surface contamination of the people accessing or articles conveyed in and out of the radiation controlled areas is detected and monitored by installing contamination monitors at the boundary of controlled areas and uncontrolled areas against the expansion of the radioactive materials to out of the facilities. It is required for the surface contamination of articles to be tightened of control criteria as 'Guidelines for discrimination ways of nonradioactive waste (not classified as radioactive waste) generated from nuclear power plants' (hereinafter referred to as 'the Guideline') was established by the Nuclear and Industrial Safety Agency of the Ministry of Economy, Trade and Industry in August, 2005. It predicts that the control criteria of monitors other than article monitors are also tightened in the future. Fuji electric has been fabricating and delivering surface contamination detecting monitors. Now we are developing the new contamination monitor corresponding to the tightening of the control criteria. 'Large article transfer monitor', 'Clothing monitor' and 'Body surface contamination monitor' are introduced in this article. (author)

Reuse of contaminated material from nuclear-power plants

International Nuclear Information System (INIS)

Melichar, Z.

1988-01-01

Some building structures of decommissioned nuclear power plants are contaminated to a very low extent. Little experience is so far available concerning the recycling and furher exploitation of such materials, the majority of which is constituted by concrete and steel. The mass and activities of the metal parts of the Bohunice A-1 nuclear power plant are estimated and the major contaminant radionuclides are listed. Czechoslovak as well as foreign regulations concerning radioactive material handling are cited and criteria for releasing such materials for further use are discussed. (M.D.). 7 tabs., 3 figs, 28 refs

Self-Replenishing Vascularized Fouling-Release Surfaces

Energy Technology Data Exchange (ETDEWEB)

Howell, C; Vu, TL; Lin, JJ; Kolle, S; Juthani, N; Watson, E; Weaver, JC; Alvarenga, J; Aizenberg, J

2014-08-13

Inspired by the long-term effectiveness of living antifouling materials, we have developed a method for the self-replenishment of synthetic biofouling-release surfaces. These surfaces are created by either molding or directly embedding 3D vascular systems into polydimethylsiloxane (PDMS) and filling them with a silicone oil to generate a nontoxic oil-infused material. When replenished with silicone oil from an outside source, these materials are capable of self-lubrication and continuous renewal of the interfacial fouling-release layer. Under accelerated lubricant loss conditions, fully infused vascularized samples retained significantly more lubricant than equivalent nonvascularized controls. Tests of lubricant-infused PDMS in static cultures of the infectious bacteria Staphylococcus aureus and Escherichia coli as well as the green microalgae Botryococcus braunii, Chlamydomonas reinhardtii, Dunaliella sauna, and Nannochloropsis oculata showed a significant reduction in biofilm adhesion compared to PDMS and glass controls containing no lubricant. Further experiments on vascularized versus nonvascularized samples that had been subjected to accelerated lubricant evaporation conditions for up to 48 h showed significantly less biofilm adherence on the vascularized surfaces. These results demonstrate the ability of an embedded lubricant-filled vascular network to improve the longevity of fouling-release surfaces.

Protection of environmental contamination by radioactive materials and remediation of environment

International Nuclear Information System (INIS)

2003-05-01

This report consisted of the environmental contamination of radioactive and non-radioactive materials. 38 important accident examples of environmental contamination of radioactive materials in the world from 1944 to 2001 are stated. Heavily polluted areas by accidents are explained, for example, Chernobyl, atomic reactor accidents, development of nuclear weapon in USA and USSR, radioactive waste in the sea. The environmental contamination ability caused by using radioactive materials, medical use, operating reactor, disposal, transferring, crashing of airplane and artificial satellite, release are reported. It contains measurements and monitor technologies, remediation technologies of environmental contamination and separation and transmutation of radioactive materials. On the environmental contamination by non-radioactive materials, transformation of the soil contamination in Japan and its control technologies are explained. Protection and countermeasure of environmental contamination of radioactive and non-radioactive materials in Japan and the international organs are presented. There are summary and proposal in the seventh chapter. (S.Y.)

Analysis of surface contaminants on beryllium and aluminum windows

International Nuclear Information System (INIS)

Gmur, N.F.

1987-06-01

An effort has been made to document the types of contamination which form on beryllium window surfaces due to interaction with a synchrotron radiation beam. Beryllium windows contaminated in a variety of ways (exposure to water and air) exhibited surface powders, gels, crystals and liquid droplets. These contaminants were analyzed by electron diffraction, electron energy loss spectroscopy, energy dispersive x-ray spectroscopy and wet chemical methods. Materials found on window surfaces include beryllium oxide, amorphous carbon, cuprous oxide, metallic copper and nitric acid. Aluminum window surface contaminants were also examined

Environmental contamination due to release of a large amount of tritium

International Nuclear Information System (INIS)

Kawai, Hiroshi

1988-01-01

Tritium release incidents have occurred many times in the Savannah Rever Plant in the U.S. A tritium release incident also took place in the Lawrence Livermore Laboratory. The present article outlines the reports by the plant and laboratory on these incidents and makes some comments on environmental contamination that may results from release of a large amount of tritium from nuclear fusion facilities. Tritium is normally released in the form of a combination of chemical compounds such as HT, DT and T 2 and oxides such as HTO, DTO and T 2 O. The percentage of the oxides is given in the reports by the plant. Oxides, which can be absorbed through the skin, are considered to be nearly a thousand times more toxic than the other type of tritium compounds. The HT type compounds (HT, DT and T 2 ) can be oxidized by microorganisms in soil into oxides (HTO, DTO and T 2 O) and therefore, great care should also given to this type of compounds. After each accidental tritium release, the health physics group of the plant collected various environmental samples, including ground surface water, milk, leaves of plants, soil and human urine, in leeward areas. Results on the contamination of surface water, fish and underground water are outlined and discussed. (Nogami, K.)

Guidance and methods for satisfying low specific activity material and surface contaminated object regulatory requirements

International Nuclear Information System (INIS)

Pope, R.B.; Shappert, L.B.; Michelhaugh, R.D.; Boyle, R.W.; Easton, E.P.; Coodk, J.R.

1998-01-01

The U.S. Department of Transportation (DOT) and the U.S. Nuclear Regulatory Commission (NRC) have prepared a comprehensive set of draft guidance for shippers and inspectors to use when applying the newly imposed regulatory requirements for low specific activity (LSA) material and surface contaminated objects (SCOs). These requirements represent significant departures in some areas from the manner in which these materials and objects were regulated by the earlier versions of the regulations. The proper interpretation and application of the regulatory criteria can require a fairly complex set of decisions be made. To assist those trying these regulatory requirements, a detailed set of logic-flow diagrams representing decisions related to multiple factors were prepared and included in the draft report for comment on Categorizing and Transporting Low Specific Activity Materials and Surface Contaminated Objects, (DOT/NRC, 1997). These logic-flow diagrams, as developed, are specific to the U.S. regulations, but were readily adaptable to the IAEA regulations. The diagrams have been modified accordingly and tied directly to specific paragraphs in IAEA Safety Series No. 6. This paper provides the logic-flow diagrams adapted in the IAEA regulations, and demonstrated how these diagrams can be used to assist consignors and inspectors in assessing compliance of shipments with the LSA material and SCO regulatory requirements. (authors)

Protocol for development of authorized release limits for concrete at U.S. Department of Energy sites

International Nuclear Information System (INIS)

Arnish, J.; Kamboj, S.; Chen, S.-Y.; Parker, F. L.; Smith, A. M.; Meservey, R. H.; Tripp, J. L.

2000-01-01

The purpose of this protocol is to assist US Department of Energy (DOE) sites in releasing concrete for reuse. Current regulations allow the sites to release surface-contaminated materials if their radioactivity falls below certain levels and to possibly release materials with volumetric contamination or higher levels of surface contamination on a case-by-case basis. In all cases, an ALARA (as low as reasonably achievable) analysis that evaluates the risks of releasing volumetrically contaminated concrete or concrete with higher levels of surface contamination is required as a basis for proposing and setting new release limits that allow for reuse of the concrete material. To evaluate the dose impacts of reusing radioactively contaminated material, the measured radiation levels (pCi/g or disintegrations per minute [dpm]/100 cm 2 ) must be converted to the estimated dose (mrem/yr) that would be received by affected individuals. The dose depends on the amounts and types of isotopes present and the time, distance, and method of exposure (e.g., inhalation or external exposure). For each disposition alternative, the protocol provides a systematic method to evaluate the impact of the dose on the affected individuals. The cost impacts of reusing concrete also need to be evaluated. They too depend on the disposition alternative and the extent and type of contamination. The protocol provides a method to perform a detailed analysis of these factors and evaluate the dose and cost impacts for various disposition alternatives. Once the dose and cost impacts of the various alternatives have been estimated, the protocol outlines the steps required to propose new release standards that allow release and reuse of the concrete material

Characterization of biochars from different sources and evaluation of release of nutrients and contaminants

Directory of Open Access Journals (Sweden)

Natália Aragão de Figueredo

Full Text Available ABSTRACT The biochar, product of pyrolysis of organic waste, has been used as a soil conditioner and alternative on solid waste management. However, the raw material and pyrolysis temperature used influence the quantity and dynamics of release of nutrients and contaminants from the biochar. The objective was to evaluate the use of waste sugarcane bagasse, eucalyptus and sewage sludge for production of biochar and determine the chemical, physical, mineralogical properties and acid extraction of these materials produced at 350 °C and 500 °C. Were evaluated the proportion of C, H, N, O; ashes; macro and micronutrients, plus some contaminants; characterization of mineral phases by diffractometry of X- rays; functional groups by infrared absorption spectroscopy (FTIR. Moreover, it was determined the release of nutrients and contaminants for the extraction in increasing concentration of HNO3 (0,01 - 2,0 mol L-1. The O/C and H/C relations decreased with increasing temperature of pyrolysis, which define a greater stability of the C of biochars. Sewage sludge biochar (BC-L had the highest nutrient release rates and contaminant metals (Cd, Cr, Ni and Pb. Acid extraction of other biochars was very low (<20% of the total content. The results indicate that the carbon fraction of biochar contributes to the low rate of release of the elements in acid place.

An analysis of the impact of native oxide, surface contamination and material density on total electron yield in the absence of surface charging effects

Energy Technology Data Exchange (ETDEWEB)

Iida, Susumu, E-mail: susumu.iida@toshiba.co.jp [EUVL Infrastructure Development Center, Inc., 16-1 Onogawa, Tsukuba-shi, Ibaraki-ken, 305-8569 (Japan); Ohya, Kaoru [Institute of Technology and Science, The University of Tokushima, 2-1 Minamijyousanjima-cho,Tokushima, 770-8506 (Japan); Hirano, Ryoichi; Watanabe, Hidehiro [EUVL Infrastructure Development Center, Inc., 16-1 Onogawa, Tsukuba-shi, Ibaraki-ken, 305-8569 (Japan)

2016-10-30

Highlights: • Total electron yields were assessed in the absence of any surface charging effect. • Experimental and simulation results showed a low native oxide energy barrier. • The yield enhancement effect of a native oxide layer was confirmed. • The yield enhancement effect of a thin surface contamination layer was confirmed. • Deviations in the material density from the theoretical values were evaluated. - Abstract: The effects of the presence of a native oxide film or surface contamination as well as variations in material density on the total electron yield (TEY) of Ru and B{sub 4}C were assessed in the absence of any surface charging effect. The experimental results were analyzed using semi-empirical Monte Carlo simulations and demonstrated that a native oxide film increased the TEY, and that this effect varied with film thickness. These phenomena were explained based on the effect of the backscattered electrons (BSEs) at the interface between Ru and RuO{sub 2}, as well as the lower potential barrier of RuO{sub 2}. Deviations in the material density from the theoretical values were attributed to the film deposition procedure based on fitting simulated TEY curves to experimental results. In the case of B{sub 4}C, the TEY was enhanced by the presence of a 0.8-nm-thick surface contamination film consisting of oxygenated hydrocarbons. The effect of the low potential barrier of the contamination film was found to be significant, as the density of the B{sub 4}C was much lower than that of the Ru. Comparing the simulation parameters generated in the present work with Joy’s database, it was found that the model and the input parameters used in the simulations were sufficiently accurate.

Using slow-release permanganate candles to remediate PAH-contaminated water.

Science.gov (United States)

Rauscher, Lindy; Sakulthaew, Chainarong; Comfort, Steve

2012-11-30

Surface waters impacted by urban runoff in metropolitan areas are becoming increasingly contaminated with polycyclic aromatic hydrocarbons (PAHs). Slow-release oxidant candles (paraffin-KMnO(4)) are a relatively new technology being used to treat contaminated groundwater and could potentially be used to treat urban runoff. Given that these candles only release permanganate when submerged, the ephemeral nature of runoff events would influence when the permanganate is released for treating PAHs. Our objective was to determine if slow-release permanganate candles could be used to degrade and mineralize PAHs. Batch experiments quantified PAH degradation rates in the presence of the oxidant candles. Results showed most of the 16 PAHs tested were degraded within 2-4 h. Using (14)C-labled phenanthrene and benzo(a)pyrene, we demonstrated that the wax matrix of the candle initially adsorbs the PAH, but then releases the PAH back into solution as transformed, more water soluble products. While permanganate was unable to mineralize the PAHs (i.e., convert to CO(2)), we found that the permanganate-treated PAHs were much more biodegradable in soil microcosms. To test the concept of using candles to treat PAHs in multiple runoff events, we used a flow-through system where urban runoff water was pumped over a miniature candle in repetitive wet-dry, 24-h cycles. Results showed that the candle was robust in removing PAHs by repeatedly releasing permanganate and degrading the PAHs. These results provide proof-of-concept that permanganate candles could potentially provide a low-cost, low-maintenance approach to remediating PAH-contaminated water. Copyright © 2012 Elsevier B.V. All rights reserved.

Biological processes influencing contaminant release from sediments

International Nuclear Information System (INIS)

Reible, D.D.

1996-01-01

The influence of biological processes, including bioturbation, on the mobility of contaminants in freshwater sediments is described. Effective mass coefficients are estimated for tubificid oligochaetes as a function of worm behavior and biomass density. The mass transfer coefficients were observed to be inversely proportional to water oxygen content and proportional to the square root of biomass density. The sediment reworking and contaminant release are contrasted with those of freshwater amphipods. The implications of these and other biological processes for contaminant release and i n-situ remediation of soils and sediments are summarized. 4 figs., 1 tab

Decontamination method for radioactively contaminated material

International Nuclear Information System (INIS)

Shoji, Yuichi; Mizuguchi, Hiroshi; Sakai, Hitoshi; Komatsubara, Masaru

1998-01-01

Radioactively contaminated materials having surfaces contaminated by radioactive materials are dissolved in molten salts by the effect of chlorine gas. The molten salts are brought into contact with a low melting point metal to reduce only radioactive materials by substitution reaction and recover them into the low melting point metal. Then, a low melting point metal phase and a molten salt phase are separated. The low melting point metal phase is evaporated to separate the radioactive materials from molten metals. On the other hand, other metal ions dissolved in the molten salts are reduced into metals by electrolysis at an anode and separated from the molten salts and served for regeneration. The low melting point metals are reutilized together with contaminated lead, after subjected to decontamination, generated from facilities such as nuclear power plant or lead for disposal. Since almost all materials including the molten salts and the molten metals can be enclosed, the amount of wastes can be reduced. In addition, radiation exposure of operators who handle them can be reduced. (T.M.)

A method of surface area measurement of fuel materials by fission gas release at low temperature

International Nuclear Information System (INIS)

Kaimal, K.N.G.; Naik, M.C.; Paul, A.R.; Venkateswarlu, K.S.

1989-01-01

The present report deals with the development of a method for surface area measurement of nuclear fuel as well as fissile doped materials by fission gas release study at low temperature. The method is based on the evaluation of knock-out release rate of fission 133 Xe from irradiated fuel after sufficient cooling to decay the short lived activity. The report also describes the fabrication of an ampoule breaker unit for such study. Knock-out release rate of 133 Xe has been studied from UO 2 powders having varying surface area 'S' ranging from 270 cm 2 /gm to 4100 cm 2 /gm at two fissioning rates 10 12 f/cm 3 . sec. and 3.2x10 10 f/cm.sec. A relation between K and A has been established and discussed in this report. (author). 6 refs

DEEP VADOSE ZONE CONTAMINATION DUE TO RELEASES FROM HANFORD SITE TANKS

International Nuclear Information System (INIS)

JARAYSI MN

2008-01-01

CH2M HILL Hanford Group, Inc. (the Hanford Tank Farm Operations contractor) and the Department of Energy's Office of River Protection have just completed the first phase of the Hanford Single-Shell Tank RCRA Corrective Action Program. The focus of this first phase was to characterize the nature and extent of past Hanford single-shell tank releases and to characterize the resulting fate and transport of the released contaminants. Most of these plumes are below 20 meters, with some reaching groundwater (at 60 to 120 meters below ground surface [bgs])

Release of radon contaminants from Yucca Mountain: The role of buoyancy driven flow

International Nuclear Information System (INIS)

Sullivan, T.M.; Pescatore, C.

1994-02-01

The potential for the repository heat source to promote buoyancy driven flow and thereby cause release of radon gas out of Yucca Mountain has been examined through a critical review of the theoretical and experimental studies of this process. The review indicates that steady-state buoyancy enhanced release of natural radon and other contaminant gases should not be a major concern at Yucca Mountain. Barometric pumping and wind pumping are identified as two processes that will have a potentially greater effect on surface releases of gases

Effects of low molecular weight organic acids on 137Cs release from contaminated soils

International Nuclear Information System (INIS)

Chiang, Po Neng; Wang, Ming Kuang; Huang, Pan Ming; Wang, Jeng Jong

2011-01-01

Radio pollutant removal is one of several priority restoration strategies for the environment. This study assessed the effect of low molecular weight organic acid on the lability and mechanisms for release of 137 Cs from contaminated soils. The amount of 137 Cs radioactivity released from contaminated soils reacting with 0.02 M low molecular weight organic acids (LMWOAs) specifically acetic, succinic, oxalic, tartaric, and citric acid over 48 h were 265, 370, 760, 850, and 1002 Bq kg -1 , respectively. The kinetic results indicate that 137 Cs exhibits a two-step parabolic diffusion equation and a good linear relationship, indicating that the parabolic diffusion equation describes the data quite well, as shown by low p and high r 2 values. The fast stage, which was found to occur within a short period of time (0.083-3 h), corresponds to the interaction of LMWOAs with the surface of clay minerals; meanwhile, during the slow stage, which occurs over a much longer time period (3-24 h), desorption primarily is attributed to inter-particle or intra-particle diffusion. After a fifth renewal of the LMWOAs, the total levels of 137 Cs radioactivity released by acetic, succinic, oxalic, tartaric, and citric acid were equivalent to 390, 520, 3949, 2061, and 4422 Bq kg -1 soil, respectively. H + can protonate the hydroxyl groups and oxygen atoms at the broken edges or surfaces of the minerals, thereby weakening Fe-O and Al-O bonds. After protonation of H + , organic ligands can attack the OH and OH 2 groups in the minerals easily, to form complexes with surface structure cations, such as Al and Fe. The amounts of 137 Cs released from contaminated soil treated with LMWOAs were substantially increased, indicating that the LMWOAs excreted by the roots of plants play a critical role in 137 Cs release.

Temporal sealing material of tritium-contaminated stainless steel

International Nuclear Information System (INIS)

Wen Wei; Dan Guiping; Zhang Dong; Qiu Yongmei; Zhang Li

2010-01-01

Tritium can be released from the exterior of tritium-contaminated stainless steel by slight stirring while decontaminating and disassembling. In order to avoid secondary tritium contamination to environment and operators, it is necessary to cover with an effective coating to tritium on the exterior of tritium-contaminated stainless steel and fill an effective substance to tritium inside. The results of tritium sealed experiments show that sealing efficiency of neutral silicone rubber is more than 85% for condition of static state and more than 99% for foam concrete condition of dynamic state. Neutral silicone rubber and foam concrete which have finer sealing efficiency can be used as temporal sealed material for the decontamination and disassembly of tritium-contaminated stainless steel. (authors)

Using slow-release permanganate candles to remediate PAH-contaminated water

International Nuclear Information System (INIS)

Rauscher, Lindy; Sakulthaew, Chainarong; Comfort, Steve

2012-01-01

Highlights: ► We quantified the efficacy of slow-release permanganate-paraffin candles to degrade and mineralize PAHs. ► 14 C-labeled PAHs were used to quantify both adsorption and transformation. ► Permanganate-treated PAHs were more biodegradable in soil microcosms. ► A flow-through candle system was used to quantify PAH removal in urban runoff. - Abstract: Surface waters impacted by urban runoff in metropolitan areas are becoming increasingly contaminated with polycyclic aromatic hydrocarbons (PAHs). Slow-release oxidant candles (paraffin–KMnO 4 ) are a relatively new technology being used to treat contaminated groundwater and could potentially be used to treat urban runoff. Given that these candles only release permanganate when submerged, the ephemeral nature of runoff events would influence when the permanganate is released for treating PAHs. Our objective was to determine if slow-release permanganate candles could be used to degrade and mineralize PAHs. Batch experiments quantified PAH degradation rates in the presence of the oxidant candles. Results showed most of the 16 PAHs tested were degraded within 2–4 h. Using 14 C-labled phenanthrene and benzo(a)pyrene, we demonstrated that the wax matrix of the candle initially adsorbs the PAH, but then releases the PAH back into solution as transformed, more water soluble products. While permanganate was unable to mineralize the PAHs (i.e., convert to CO 2 ), we found that the permanganate-treated PAHs were much more biodegradable in soil microcosms. To test the concept of using candles to treat PAHs in multiple runoff events, we used a flow-through system where urban runoff water was pumped over a miniature candle in repetitive wet–dry, 24-h cycles. Results showed that the candle was robust in removing PAHs by repeatedly releasing permanganate and degrading the PAHs. These results provide proof-of-concept that permanganate candles could potentially provide a low-cost, low-maintenance approach to

Using slow-release permanganate candles to remediate PAH-contaminated water

Energy Technology Data Exchange (ETDEWEB)

Rauscher, Lindy, E-mail: purplerauscher@neb.rr.com [School of Natural Resources, University of Nebraska, Lincoln, NE 68583-0915 (United States); Sakulthaew, Chainarong, E-mail: chainarong@huskers.unl.edu [School of Natural Resources, University of Nebraska, Lincoln, NE 68583-0915 (United States); Department of Veterinary Technology, Kasetsart University, Bangkok 10900 (Thailand); Comfort, Steve, E-mail: scomfort1@unl.edu [School of Natural Resources, University of Nebraska, Lincoln, NE 68583-0915 (United States)

2012-11-30

Highlights: Black-Right-Pointing-Pointer We quantified the efficacy of slow-release permanganate-paraffin candles to degrade and mineralize PAHs. Black-Right-Pointing-Pointer {sup 14}C-labeled PAHs were used to quantify both adsorption and transformation. Black-Right-Pointing-Pointer Permanganate-treated PAHs were more biodegradable in soil microcosms. Black-Right-Pointing-Pointer A flow-through candle system was used to quantify PAH removal in urban runoff. - Abstract: Surface waters impacted by urban runoff in metropolitan areas are becoming increasingly contaminated with polycyclic aromatic hydrocarbons (PAHs). Slow-release oxidant candles (paraffin-KMnO{sub 4}) are a relatively new technology being used to treat contaminated groundwater and could potentially be used to treat urban runoff. Given that these candles only release permanganate when submerged, the ephemeral nature of runoff events would influence when the permanganate is released for treating PAHs. Our objective was to determine if slow-release permanganate candles could be used to degrade and mineralize PAHs. Batch experiments quantified PAH degradation rates in the presence of the oxidant candles. Results showed most of the 16 PAHs tested were degraded within 2-4 h. Using {sup 14}C-labled phenanthrene and benzo(a)pyrene, we demonstrated that the wax matrix of the candle initially adsorbs the PAH, but then releases the PAH back into solution as transformed, more water soluble products. While permanganate was unable to mineralize the PAHs (i.e., convert to CO{sub 2}), we found that the permanganate-treated PAHs were much more biodegradable in soil microcosms. To test the concept of using candles to treat PAHs in multiple runoff events, we used a flow-through system where urban runoff water was pumped over a miniature candle in repetitive wet-dry, 24-h cycles. Results showed that the candle was robust in removing PAHs by repeatedly releasing permanganate and degrading the PAHs. These results provide

Containing and discarding method for radiation contaminated materials and radiation contaminated material containing composite member

International Nuclear Information System (INIS)

Akagawa, Katsuhiko.

1995-01-01

A container for high level radiation contaminated materials is loaded in an outer container in a state of forming a gap between the outer container and a container wall, low level radiation contaminated materials are filled to the gap between the container of the radiation contaminated materials and the container wall, and then the outer container is sealed. In addition, the thickness of the layer of the low level radiation contaminated materials is made substantially uniform. Then, since radiation rays from the container of the radiation contaminated materials are decayed by the layer of the low level radiation contaminated materials at the periphery of the container and the level of the radiation rays emitted from the outer container is extremely reduced than in a case where the entire amount of high level radiation contaminated materials are filled, the level is suppressed to an extent somewhat higher than the level in the case where the entire amount of the low level radiation contaminated materials are filled. Accordingly, the management corresponds to that for the low level radiation contaminated materials, and the steps for the management and the entire volume thereof are reduced than in a case where the high level radiation contaminated materials and the low level radiation contaminated materials are sealed separately. (N.H.)

The effect of release liner materials on adhesive contaminants, paper recycling and recycled paper properties

Science.gov (United States)

Richard Venditti; Richard Gilbert; Andy Zhang; Said Abubakr

2000-01-01

Release liner waste material is found in post-consumer waste streams and is also a significant component of the preconsumer waste stream generated in the manufacturing of adhesive products. To date, very little has been reported pertaining to the behavior of release liner in paper recycling. In this study, the effect of the release liner material on the behavior of...

Standard Test Method for Contamination Outgassing Characteristics of Spacecraft Materials

CERN Document Server

American Society for Testing and Materials. Philadelphia

2009-01-01

1.1 This test method covers a technique for generating data to characterize the kinetics of the release of outgassing products from materials. This technique will determine both the total mass flux evolved by a material when exposed to a vacuum environment and the deposition of this flux on surfaces held at various specified temperatures. 1.2 This test method describes the test apparatus and related operating procedures for evaluating the total mass flux that is evolved from a material being subjected to temperatures that are between 298 and 398 K. Pressures external to the sample effusion cell are less than 7 × 10−3 Pa (5 × 10−5 torr). Deposition rates are measured during material outgassing tests. A test procedure for collecting data and a test method for processing and presenting the collected data are included. 1.3 This test method can be used to produce the data necessary to support mathematical models used for the prediction of molecular contaminant generation, migration, and deposition. 1.4 Al...

Radioactive contamination of some rubber or plastic surfaces by fission products. Decontamination tests

International Nuclear Information System (INIS)

Mestre, E.; Sautiez, N.

1957-10-01

With the objective of notably addressing the contamination and decontamination of gloves and floor covering, this report first presents some characteristics of contaminating radioactive materials (nature, physical and chemical condition), of contaminated surfaces (surface condition, surface nature), and of decontamination processes (physical, chemical or mechanical action). It describes the operational modality implemented to test decontamination processes on various glove or flooring materials: sample preparation, counting, decontamination, reproducibility of decontamination tests, results in terms of activity reduction. It more precisely describes the tested samples: short gloves, gloves from glove boxes, floor and wall coverings. Results are presented and discussed in terms of sample susceptibility to contamination, and of decontamination, but also for re-contamination tests after a Nab-based decontamination (susceptibility to contamination, decontamination gain)

Natural and technologic hazardous material releases during and after natural disasters: a review.

Science.gov (United States)

Young, Stacy; Balluz, Lina; Malilay, Josephine

2004-04-25

Natural disasters may be powerful and prominent mechanisms of direct and indirect hazardous material (hazmat) releases. Hazardous materials that are released as the result of a technologic malfunction precipitated by a natural event are referred to as natural-technologic or na-tech events. Na-tech events pose unique environmental and human hazards. Disaster-associated hazardous material releases are of concern, given increases in population density and accelerating industrial development in areas subject to natural disasters. These trends increase the probability of catastrophic future disasters and the potential for mass human exposure to hazardous materials released during disasters. This systematic review summarizes direct and indirect disaster-associated releases, as well as environmental contamination and adverse human health effects that have resulted from natural disaster-related hazmat incidents. Thorough examination of historic disaster-related hazmat releases can be used to identify future threats and improve mitigation and prevention efforts.

Combined Contamination and Space Environmental Effects on Solar Cells and Thermal Control Surfaces

Science.gov (United States)

Dever, Joyce A.; Bruckner, Eric J.; Scheiman, David A.; Stidham, Curtis R.

1994-01-01

For spacecraft in low Earth orbit (LEO), contamination can occur from thruster fuel, sputter contamination products and from products of silicone degradation. This paper describes laboratory testing in which solar cell materials and thermal control surfaces were exposed to simulated spacecraft environmental effects including contamination, atomic oxygen, ultraviolet radiation and thermal cycling. The objective of these experiments was to determine how the interaction of the natural LEO environmental effects with contaminated spacecraft surfaces impacts the performance of these materials. Optical properties of samples were measured and solar cell performance data was obtained. In general, exposure to contamination by thruster fuel resulted in degradation of solar absorptance for fused silica and various thermal control surfaces and degradation of solar cell performance. Fused silica samples which were subsequently exposed to an atomic oxygen/vacuum ultraviolet radiation environment showed reversal of this degradation. These results imply that solar cells and thermal control surfaces which are susceptible to thruster fuel contamination and which also receive atomic oxygen exposure may not undergo significant performance degradation. Materials which were exposed to only vacuum ultraviolet radiation subsequent to contamination showed slight additional degradation in solar absorptance.

Release of low-contaminated reactor wastes for unrestricted use

International Nuclear Information System (INIS)

Carleson, G.

1982-01-01

A generic methodology has been used to evaluate the dose contributions to an individual and to the population of five categories of low-contaminated reactor wastes produced according to the Swedish program and released for unrestricted handling and use. A reference quantity with a surface dose rate below a predetermined level is followed along the whole commercial pathway from the reactor station to the final product consumer and/or a municipal waste station. Dose contributions are calculated for each step in a normal pathway under maximally unfavourable conditions. (Auth.)

Release behavior of triazine residues in stabilised contaminated soils

International Nuclear Information System (INIS)

Ying, G.G.; Kookana, R.S.; Mallavarpu, M.

2005-01-01

This paper reports the release behavior of two triazines (atrazine and simazine) in stabilised soils from a pesticide-contaminated site in South Australia. The soils were contaminated with a range of pesticides, especially with triazine herbicides. With multiple extractions of each soil sample with deionised water (eight in total), 15% of atrazine and 4% of simazine residues were recovered, resulting in very high concentrations of the two herbicides in leachate. The presence of small fractions of surfactants was found to further enhance the release of the residues. Methanol content up to 10% did not substantially influence the concentration of simazine and atrazine released. The study demonstrated that while the stabilisation of contaminated soil with particulate activated carbon (5%) and cement mix (15%) was effective in locking the residues of some pesticides, it failed to immobilise triazine herbicides residues completely. Given the higher water solubility of these herbicides than other compounds more effective strategies to immobilise their residues is needed. - Stabilisation of contaminated soil with a mix of activated carbon and cement may fail to immobilise some contaminants like triazines

OPERATIONAL LIMITATIONS FOR DEMOLITION OF A HIGHLY ALPHA CONTAMINATED BUILDING MODLES VERSUS MEASURED AIR & SURFACE ACTIVITY CONCENTRATIONS

Energy Technology Data Exchange (ETDEWEB)

LLOYD, E.R.

2006-11-02

The demolition of a facility historically used for processing and handling transuranic materials is considered. Residual alpha emitting radionuclide contamination poses an exposure hazard if released to the local environment during the demolition. The process of planning for the demolition of this highly alpha contaminated building, 232-Z, included a predemolition modeling analysis of potential exposures. Estimated emission rates were used as input to an air dispersion model to estimate frequencies of occurrence of peak air and surface exposures. Postdemolition modeling was also conducted, based on the actual demolition schedule and conditions. The modeling results indicated that downwind deposition is the main operational limitation for demolition of a highly alpha-contaminated building. During the demolition of 232-Z, airborne radiation and surface contamination were monitored. The resultant non-detect monitoring results indicate a significant level of conservatism in the modeled results. This comparison supports the use of more realistic assumption in the estimating emission rates. The resultant reduction in modeled levels of potential exposures has significant implications in terms of the projected costs of demolition of such structures.

Model for absorption and release of gaseous materials by forest canopies

International Nuclear Information System (INIS)

Murphy, C.E. Jr.

1976-01-01

A model of the physical processes defining the absorption and release of materials by a forest canopy has been developed. The model deals with the turbulent transport of gaseous materials in the surface boundary layer near the canopy, the turbulent transport in the canopy atmosphere, the transport through the boundary layer near the leaf and soil surface, and the solution of the gaseous materials in intracellular fluids and subsequent diffusion into the leaf cells. The model is used to simulate the uptake of molecular tritium by the forest canopy and the subsequent release of tritiated water. Results of dynamic simulations of tritium uptake and release are compared with data collected at the time of a release of molecular tritium to the atmosphere

Evaluation of the contribution of contamination of radiotherapy room surfaces in the measure of exposure rate of radioiodine therapy patients

International Nuclear Information System (INIS)

Campos, Rafael Ferreira

2015-01-01

The contamination of radiotherapy room surfaces is significant and the measures of patient exposure rate are held on the fourth dependencies, relevant questions are raised: the background radiation of the room stay high due to surface contamination, may interfere with the rate of patient exposure at the time of its release? The monitoring site is important to determine whether the patient will be released? The value of the deal activity and the clinical condition of the patient may increase the contamination, influencing the monitoring results? This paper aims to conduct a quantitative analysis of surface contamination of the contribution of therapeutic room at the time is monitored exposure rate from inpatient. Measurements were made regarding the hospitalization of 32 patients with different doses administered activity, age and of both genders. The measurements were performed in the therapeutic rooms at the hospital Brotherhood Santa Casa de Misericordia de Sao Paulo. Exposure rate measurements were performed at the center of the room at 1 meter of the patient on the day of its release. After his release and prior to decontamination, measurements were performed at predetermined landmarks within the therapeutic room. The results revealed that on average background radiation, high due to surface contamination contributes only 2% of the patient dose rate. It can be considered that even with influence of contamination of surfaces, this is insignificant to determine if the patient may or may not be released. This study suggests that the site in which monitoring occurs exposure rate of the patient should not be decisive for liberation thereof. (author)

Radioactive contamination of some rubber or plastic surfaces by fission products. Decontamination tests; Contamination radioactive de quelques surfaces en caoutchouc ou en matiere plastique par des produits de fission. Essais de decontamination

Energy Technology Data Exchange (ETDEWEB)

Mestre, E.; Sautiez, N.

1957-10-15

With the objective of notably addressing the contamination and decontamination of gloves and floor covering, this report first presents some characteristics of contaminating radioactive materials (nature, physical and chemical condition), of contaminated surfaces (surface condition, surface nature), and of decontamination processes (physical, chemical or mechanical action). It describes the operational modality implemented to test decontamination processes on various glove or flooring materials: sample preparation, counting, decontamination, reproducibility of decontamination tests, results in terms of activity reduction. It more precisely describes the tested samples: short gloves, gloves from glove boxes, floor and wall coverings. Results are presented and discussed in terms of sample susceptibility to contamination, and of decontamination, but also for re-contamination tests after a Nab-based decontamination (susceptibility to contamination, decontamination gain)

Efficient reconstruction of contaminant release history

Energy Technology Data Exchange (ETDEWEB)

Alezander, Francis [Los Alamos National Laboratory; Anghel, Marian [Los Alamos National Laboratory; Gulbahce, Natali [NON LANL; Tartakovsky, Daniel [NON LANL

2009-01-01

We present a generalized hybrid Monte Carlo (GHMC) method for fast, statistically optimal reconstruction of release histories of reactive contaminants. The approach is applicable to large-scale, strongly nonlinear systems with parametric uncertainties and data corrupted by measurement errors. The use of discrete adjoint equations facilitates numerical implementation of GHMC, without putting any restrictions on the degree of nonlinearity of advection-dispersion-reaction equations that are used to described contaminant transport in the subsurface. To demonstrate the salient features of the proposed algorithm, we identify the spatial extent of a distributed source of contamination from concentration measurements of a reactive solute.

SRNL EMERGENCY RESPONSE CAPABILITY FOR ATMOSPHERIC CONTAMINANT RELEASES

International Nuclear Information System (INIS)

Koffman, L; Chuck Hunter, C; Robert Buckley, R; Robert Addis, R

2006-01-01

Emergency response to an atmospheric release of chemical or radiological contamination is enhanced when plume predictions, field measurements, and real-time weather information are integrated into a geospatial framework. The Weather Information and Display (WIND) System at Savannah River National Laboratory (SRNL) utilizes such an integrated framework. The rapid availability of predictions from a suite of atmospheric transport models within this geospatial framework has proven to be of great value to decision makers during an emergency involving an atmospheric contaminant release

Hydrogen Contamination of Niobium Surfaces

International Nuclear Information System (INIS)

Viet Nguyen-Tuong; Lawrence Doolittle

1993-01-01

The presence of hydrogen is blamed for dramatic reductions in cavity Q's. Hydrogen concentration is difficult to measure, so there is a great deal of Fear, Uncertainty, and Doubt (FUD) associated with the problem. This paper presents measurements of hydrogen concentration depth profiles, commenting on the pitfalls of the methods used and exploring how material handling can change the amount of hydrogen in pieces of niobium. Hydrogen analysis was performed by a forward scattering experiment with Helium used as the primary beam. This technique is variously known as FRES (Forward Recoil Elastic Scattering), FRS, HFS (Hydrogen Forward Scattering), and HRA (Hydrogen Recoil Analysis). Some measurements were also made using SIMS (Secondary Ion Mass Spectrometry). Both HFS and SIMS are capable of measuring a depth profile of Hydrogen. The primary difficulty in interpreting the results from these techniques is the presence of a surface peak which is due (at least in part) to contamination with either water or hydrocarbons. With HFS, the depth resolution is about 30 nm, and the maximum depth profiled is about 300 nm. (This 10-1 ratio is unusually low for ion beam techniques, and is a consequence of the compromises that must be made in the geometry of the experiment, surface roughness, and energy straggling in the absorber foil that must be used to filter out the forward scattered helium.) All the observed HFS spectra include a surface peak which includes both surface contamination and any real hydrogen uptake by the niobium surface. Some contamination occurs during the analysis. The vacuum in the analysis chamber is typically a few times 10(sup -6) torr, and some of the contamination is in the form of hydrocarbons from the pumping system. Hydrocarbons normally form a very thin (less than a monolayer) film which is in equilibrium between arrival rate and the evaporation rate. In the presence of the incoming ion beam, however, these hydrocarbons crack on the surface into non

Removal and treatment of radioactive, organochlorine, and heavy metal contaminants from solid surfaces

International Nuclear Information System (INIS)

Grieco, S.A.; Neubauer, E.D.

1996-01-01

The U.S. Department of Energy (DOE) is defining decontamination and decommissioning (D ampersand D) obligations at its sites. Current D ampersand D activities are generally labor intensive, use chemical reagents that are difficult to treat, and may expose workers to radioactive and hazardous chemicals. Therefore, new technologies are desired that minimize waste, allow much of the decommissioned materials to be reused rather than disposed of as waste, and produce wastes that will meet disposal criteria. The O'Brien ampersand Gere companies tested a scouring decontamination system on concrete and steel surfaces contaminated with radioactive and hazardous wastes under the sponsorship of Martin Marietta Energy Systems, Inc. (MMES) at DOE's K-25 former gaseous diffusion plant in Oak Ridge, Tennessee. The scouring system removes fixed radioactive and hazardous contamination yet leaves the surface intact. Blasting residuals are treated using physical/chemical processes. Bench- and pilot-scale testing of the system was conducted on surfaces contaminated with uranium, technetium, heavy metals, and PCBs. Areas of concrete and metal surfaces were blasted. Residuals were dissolved in tap water and treated for radioactive, hazardous, and organochlorine constituents. The treatment system comprised pH adjustment, aeration, solids settling, filtration, carbon adsorption, and ion exchange. This system produced treated water and residual solid waste. Testing demonstrated that the system is capable of removing greater than 95% of radioactive and PCB surface contamination to below DOE's unrestricted use release limits; aqueous radionuclides, heavy metals, and PCBs were below DOE and USEPA treatment objectives after treatment. Waste residuals volume was decreased by 71 %. Preliminary analyses suggest that this system provides significant waste volume reduction and is more economical than alternative surface decontamination techniques that are commercially available or under development

Contamination and restoration of an estuary affected by phosphogypsum releases

International Nuclear Information System (INIS)

Villa, M.; Mosqueda, F.; Hurtado, S.; Mantero, J.; Manjon, G.; Perianez, R.; Vaca, F.; Garcia-Tenorio, R.

2009-01-01

The Huelva Estuary in Huelva, Spain, has been one of the most studied environmental compartments in the past years from the point of view of naturally occurring radioactive material (NORM) releases. It has been historically affected by waste releases, enriched in radionuclides from the U-decay series, from factories located in the area devoted to the production of phosphoric acid and phosphate fertilizers. Nevertheless, changes in national regulations forced a new waste management practice in 1998, prohibiting releases of phosphogypsum into the rivers. The input of natural radionuclides from phosphate factories to rivers was drastically reduced. Because of this there was a unique opportunity for the study of the response of a contaminated environmental compartment, specifically an estuary affected by tidal influences, after the cessation of the contaminant releases to, in this case, the Huelva Estuary (henceforth referred to as the Estuary). To investigate the environmental response to this new discharge regime, the specific activities of radionuclides 226 Ra and 210 Pb in water and sediment samples collected in four campaigns (from 1999 to 2005) were determined and compared with pre-1998 values. From this study it is possible to infer the most effective mechanisms of decontamination for the Estuary. Decontamination rates of 210 Pb and 226 Ra in the sediments and water have been calculated using exponential fittings and corresponding half-lives have been deduced from them. The cleaning half-life in the whole area of the Estuary is about 6 and 3.5 years for 226 Ra and 210 Pb respectively. The observed trend clearly shows that contamination of the Estuary by natural radionuclides is now decreasing and radioactive levels in waters and sediments are approaching the natural background references. This work attempts to evaluate whether it can be expected that the decontamination of the enhanced levels of natural radioactivity in the Estuary can be performed via natural

Concrete decontamination: two innovative processes in response to surface or deep contamination

International Nuclear Information System (INIS)

CUER, F.; Nadai, A. de; Faure, S.

2008-01-01

To meet the future needs in the nuclear industry as regards dismantling and decommissioning, the LPAD (Laboratoire des Procedes Avances de Decontamination) develops new specific techniques to decontaminate concretes: the drying gel process adapted to surface contamination and the electrokinetics process to treat deep contamination. Indeed, because the concrete constitute a porous medium, two types of contamination can be met according to the environment to which is subjected the material. In the case of an accidental or dry contamination, radio elements do not penetrate beyond the first millimeters of the material. The contamination is then considered as surface. On the contrary, the contamination is considered as 'deep' when radioactive ions have diffused deeply under the effects of the natural diffusion. This is the case in fuel storage pond or other many nuclear infrastructures. (authors)

Release of polyaromatic hydrocarbons from coal tar contaminated soils

International Nuclear Information System (INIS)

Priddy, N.D.; Lee, L.S.

1996-01-01

A variety of process wastes generated from manufactured gas production (MGP) have contaminated soils and groundwater at production and disposal sites. Coal tar, consisting of a complex mixture of hydrocarbons present as a nonaqueous phase liquid, makes up a large portion of MGP wastes. Of the compounds in coal tar, polyaromatic hydrocarbons (PAHs) are the major constituents of environmental concern due to their potential mutagenic and carcinogenic hazards. Characterization of the release of PAHs from the waste-soil matrix is essential to quantifying long-term environmental impacts in soils and groundwater. Currently, conservative estimates for the release of PAHs to the groundwater are made assuming equilibrium conditions and using relationships derived from artificially contaminated soils. Preliminary work suggests that aged coal tar contaminated soils have much lower rates of desorption and a greater affinity for retaining organic contaminants. To obtain better estimates of desorption rates, the release of PAHs from a coal tar soil was investigated using a flow-interruption, miscible displacement technique. Methanol/water solutions were employed to enhance PAH concentrations above limits of detection. For each methanol/water solution employed, a series of flow interrupts of varying times was invoked. Release rates from each methanol/water solution were estimated from the increase in concentration with duration of flow interruption. Aqueous-phase release rates were then estimated by extrapolation using a log-linear cosolvency model

Development of portable and automatic smear sampler for measuring surface contamination

Energy Technology Data Exchange (ETDEWEB)

Lee, Bong Jae; Chang, S. Y.; Kim, B. H.; Kim, J. S.; Lee, H. S.; Kim, C. K.; Swol, C. W

2000-12-01

In measuring radioactive contamination in radiation controlled area of nuclear facility, the technical criteria to evaluate surface contamination level and to sample by indirect method was established in this paper. Radioactive materials always present on surface within operating nuclear facilities. Because of the presence of interfering radiation field, health physicists take smear samples to monitoring surface contamination according to routine monitoring program. But there are some problems like great errors and difference of personnel. Then, to solve them, The portable and automatic smear sampling apparatus was designed and fabricated.

Development of portable and automatic smear sampler for measuring surface contamination

International Nuclear Information System (INIS)

Lee, Bong Jae; Chang, S. Y.; Kim, B. H.; Kim, J. S.; Lee, H. S.; Kim, C. K.; Swol, C. W.

2000-12-01

In measuring radioactive contamination in radiation controlled area of nuclear facility, the technical criteria to evaluate surface contamination level and to sample by indirect method was established in this paper. Radioactive materials always present on surface within operating nuclear facilities. Because of the presence of interfering radiation field, health physicists take smear samples to monitoring surface contamination according to routine monitoring program. But there are some problems like great errors and difference of personnel. Then, to solve them, The portable and automatic smear sampling apparatus was designed and fabricated

Estimating dermal transfer from PCB-contaminated porous surfaces.

Science.gov (United States)

Slayton, T M; Valberg, P A; Wait, A D

1998-06-01

Health risks posed by dermal contact with PCB-contaminated porous surfaces have not been directly demonstrated and are difficult to estimate indirectly. Surface contamination by organic compounds is commonly assessed by collecting wipe samples with hexane as the solvent. However, for porous surfaces, hexane wipe characterization is of limited direct use when estimating potential human exposure. Particularly for porous surfaces, the relationship between the amount of organic material collected by hexane and the amount actually picked up by, for example, a person's hand touch is unknown. To better mimic PCB pickup by casual hand contact with contaminated concrete surfaces, we used alternate solvents and wipe application methods that more closely mimic casual dermal contact. Our sampling results were compared to PCB pickup using hexane-wetted wipes and the standard rubbing protocol. Dry and oil-wetted samples, applied without rubbing, picked up less than 1% of the PCBs picked up by the standard hexane procedure; with rubbing, they picked up about 2%. Without rubbing, saline-wetted wipes picked up 2.5%; with rubbing, they picked up about 12%. While the nature of dermal contact with a contaminated surface cannot be perfectly reproduced with a wipe sample, our results with alternate wiping solvents and rubbing methods more closely mimic hand contact than the standard hexane wipe protocol. The relative pickup estimates presented in this paper can be used in conjunction with site-specific PCB hexane wipe results to estimate dermal pickup rates at sites with PCB-contaminated concrete.

Optical measurements on contaminated surfaces

Science.gov (United States)

Bonham, T. E.; Schmitt, R. J.; Linford, R. M. F.

1975-01-01

A bidirectional reflectometer system was developed for in situ measurements of the changes in spectral reflectance of surfaces contaminated with films of organic materials. The system permits experiments with films of controlled thickness in an environment that simulates the thermal, radiation, and vacuum conditions of space. The mechanical and optical construction of the reflectometer are discussed in detail, and actual data curves are used to illustrate its operation and performance.

Removal of PCB from indoor air and surface materials by introduction of additional sorbing materials

DEFF Research Database (Denmark)

Gunnarsen, Lars Bo; Lyng, Nadja; Kolarik, Barbara

2017-01-01

Alleviation of indoor PCB contamination is extremely expensive because PCB from old primary sources has redistributed to most other surfaces over time. This study investigates the introduction of new removable sorbing materials as a method instantly lowering the concentration of PCB in indoor air...... and slowly decontaminating old surface materials. In three bedrooms of a contaminated apartment respectively new painted gypsum boards, sheets of flexible polyurethane foam and activated carbon fabric were introduced. The PCB concentrations in room air were monitored before the intervention and several times...... during the following 10 months. The PCB concentrations in the old surface materials as well as the new materials were also measured. An immediate reduction of PCB concentration in indoor air, a gradual increase of PCB in new material and as well a gradual reduction in old surface materials were...

Levels of surface contamination with radioactive materials at workplaces of nuclear research centre at Rez

International Nuclear Information System (INIS)

Hoelgye, Z.; Nemcova, I.; Kasikova, M.; Popper, J.; Chysky, J.

1983-01-01

A hygiene supervision unit at workplaces of the nuclear Research Institute in Rez monitored on a long-term basis surface contamination with radioactive substances. Surface contamination was found at workplaces with open sources. Of the 4343 monitored places action levels were only exceeded in 13 cases. The obtained data were used for typifying workplaces with the highest level of surface contamination, to determine in certain instances the mechanism of the escape of radioactive substances from insulating facilities and to determine the rate of the spread of the radioactive substance into adjacent non-active workplaces. (author)

Contaminative Influence of Beef Due to the Inhalation of Air and the Ingestion of Soil of Livestock from an Acute Release of Radioactive Materials

International Nuclear Information System (INIS)

Hwang, Won Tae; Kim, Eun Han; Suh, Kyung Suk; Jeong, Hyo Jeon; Han, Moon Hee

2004-01-01

The contaminative influence of beef due to the inhalation of air and the ingestion of soil of livestock, both of which are dealt with as minor contaminative pathways in most radioecological models but may not be neglected, was comprehensively investigated with the improvement of the Korean food chain model DYNACON. As the results, it was found that both pathways can not be neglected at all in the contamination of beef in the case of an accidental release during the non-grazing period of livestock. The ingestion of soil was more influential in the contamination of beef than the inhalation of air over most time following an release. If precipitation is encountered during an accidental release, contaminative influence due to the ingestion of soil was far greater compared with the cases of no precipitation. This fact was more distinct for a long-lived radionuclide 137 Cs than a short-lived radionuclide '1 31 I (elemental iodine). Compared with the results for milk performed prior to this study, the contaminative pathways due to the inhalation of air and the ingestion of soil were more important in beef because of longer biological half-lives. On the other hand, in the case of an accidental release during the grazing period of livestock, radioactive contamination due to the ingestion of pasture was dominant irrespective of the existence of precipitation during an accidental release. It means that contaminative influence due to the inhalation of air and the ingestion of soil is negligible, like the cases of milk.

Contaminative influence of beef due to the inhalation of air and the ingestion of soil of cattle in an accidental release of radioactive materials

International Nuclear Information System (INIS)

Hwang, W. T.; Kim, E. H.; Seo, K. S.; Jung, H. J.; Lee, S. M.; Hang, M. H.

2004-01-01

The contaminative influence of beef due to the inhalation of air and the ingestion of soil of cattle, both of which are dealt with as minor contaminative pathways in most radioecological models but may not be neglected, was comprehensively investigated with the improvement of the Korean dynamic food chain model DYNACON. As the results, it was found that both pathways can not be neglected at all in the contamination of beef in the case of an accidental release during the non-grazing period of cattle. The ingestion of soil was more influential in the contamination of beef than the inhalation of air over most time following an release. If precipitation is encountered during an accidental release, contaminative influence due to the ingestion of soil was far greater compared with the cases of no precipitation. This fact was more distinct for a long-lived radionuclide 137 Cs than a short-lived radionuclide 131 I (elemental iodine). Compared with the results for milk performed prior to this study, the contaminative pathways due to the inhalation of air and the ingestion of soil were more important in beef because of longer biological half-lives. In the meantime, in the case of an accidental release during the grazing period of cattle, radioactive contamination due to the ingestion of pasture was dominant irrespective of the existence of precipitation during an accidental release. It means that contaminative influence due to the inhalation of air and the ingestion of soil is negligible like the cases of milk

Detection of contaminant plumes released from landfills : Numerical versus analytical solutions

NARCIS (Netherlands)

Yenigül, N.B.; Hensbergen, A.T.; Elfeki, A.M.M.; Dekking, F.M.

2011-01-01

Contaminant leaks released from landfills are a threat to groundwater quality. The groundwater monitoring systems installed in the vicinity of such facilities are vital. In this study the detection probability of a contaminant plume released from a landfill has been investigated by means of both a

Conditional release of materials from decommissioning process into the environment in the form of steel railway tracks

International Nuclear Information System (INIS)

Tatransky, Peter; Necas, Vladimir

2009-01-01

This work points to the possibilities of conditional release of materials from the process of decommissioning the nuclear unit from the operation. According to the valid legislation, materials which do not meet the condition of direct-unconditional release into the environment, should be modified and processed into the matrix designed for the final disposal in the storing place. However there exists a group of materials which activity is on the borderline of the limit of releasing into the environment and it is possible to release them conditionally. The matter of conditional release is that notable amount of materials, mainly metals, is usually contaminated only by radionuclids with relatively short time of half decay. These materials are suitable to use for a specific industrial purpose where the longtime fixation of shortly living radionuclids is expected in one place. This work deals with the conditional release of metals into the form of steel railway tracks. It describes the (working) groups of workers working with the steel railway tracks and defines in the numbers the critical group and its critical individual. For critical individual it dimensions the amounts of materials, which are possible to be released conditionally from one double-unit of the plant of the type VVER 440 V-230 which operation was ended on the regular basis. According to the calculations in the software VISIPLAN and OMEGA there is defined a number of released steel in such way that the internationally recommended rate of maximal effective dose for critical individual-10 μSv/year [IAEA, 2008. Managing low radioactivity material from the decommissioning of nuclear facility. Technical reports series no. 462] is not extended. In the final part there are compared the estimates of the costs of the decommissioning process with the application of conditional release and without it, which is directly reflected in the amount of saved costs and number of containers for surface disposal.

Transport of contaminants by Arctic sea ice and surface ocean currents

International Nuclear Information System (INIS)

Pfirman, S.

1995-01-01

Sea ice and ocean currents transport contaminants in the Arctic from source areas on the shelves, to biologically active regions often more than a thousand kilometers away. Coastal regions along the Siberian margin are polluted by discharges of agricultural, industrial and military wastes in river runoff, from atmospheric deposition and ocean dumping. The Kara Sea is of particular concern because of deliberate dumping of radioactive waste, as well as the large input of polluted river water. Contaminants are incorporated in ice during suspension freezing on the shelves, and by atmospheric deposition during drift. Ice releases its contaminant load through brine drainage, surface runoff of snow and meltwater, and when the floe disintegrates. The marginal ice zone, a region of intense biological activity, may also be the site of major contaminant release. Potentially contaminated ice from the Kara Sea is likely to influence the marginal ice zones of the Barents and Greenland seas. From studies conducted to date it appears that sea ice from the Kara Sea does not typically enter the Beaufort Gyre, and thus is unlikely to affect the northern Canadian and Alaskan margins

Contamination and restoration of an estuary affected by phosphogypsum releases

Energy Technology Data Exchange (ETDEWEB)

Villa, M., E-mail: mvilla@us.es [Centro de Investigacion, Tecnologia e Innovacion, Universidad de Sevilla CITIUS, Av. Reina Mercedes 4B, E41012-Sevilla (Spain); Mosqueda, F. [Dpto. de Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, Campus de El Carmen, 21007-Huelva (Spain); Hurtado, S. [Centro de Investigacion, Tecnologia e Innovacion, Universidad de Sevilla CITIUS, Av. Reina Mercedes 4B, E41012-Sevilla (Spain); Mantero, J.; Manjon, G. [E. T. S. Arquitectura, Universidad de Sevilla, Departamento de Fisica Aplicada II, Av. Reina Mercedes, 2. 41012-Sevilla (Spain); Perianez, R. [E.U.I.T.A., Universidad de Sevilla, Departamento de Fisica Aplicada III, Carretera de Utrera, Km. 1, 41013 Sevilla (Spain); Vaca, F. [Dpto. de Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, Campus de El Carmen, 21007-Huelva (Spain); Garcia-Tenorio, R. [E. T. S. Arquitectura, Universidad de Sevilla, Departamento de Fisica Aplicada II, Av. Reina Mercedes, 2. 41012-Sevilla (Spain)

2009-12-15

The Huelva Estuary in Huelva, Spain, has been one of the most studied environmental compartments in the past years from the point of view of naturally occurring radioactive material (NORM) releases. It has been historically affected by waste releases, enriched in radionuclides from the U-decay series, from factories located in the area devoted to the production of phosphoric acid and phosphate fertilizers. Nevertheless, changes in national regulations forced a new waste management practice in 1998, prohibiting releases of phosphogypsum into the rivers. The input of natural radionuclides from phosphate factories to rivers was drastically reduced. Because of this there was a unique opportunity for the study of the response of a contaminated environmental compartment, specifically an estuary affected by tidal influences, after the cessation of the contaminant releases to, in this case, the Huelva Estuary (henceforth referred to as the Estuary). To investigate the environmental response to this new discharge regime, the specific activities of radionuclides {sup 226}Ra and {sup 210}Pb in water and sediment samples collected in four campaigns (from 1999 to 2005) were determined and compared with pre-1998 values. From this study it is possible to infer the most effective mechanisms of decontamination for the Estuary. Decontamination rates of {sup 210}Pb and {sup 226}Ra in the sediments and water have been calculated using exponential fittings and corresponding half-lives have been deduced from them. The cleaning half-life in the whole area of the Estuary is about 6 and 3.5 years for {sup 226}Ra and {sup 210}Pb respectively. The observed trend clearly shows that contamination of the Estuary by natural radionuclides is now decreasing and radioactive levels in waters and sediments are approaching the natural background references. This work attempts to evaluate whether it can be expected that the decontamination of the enhanced levels of natural radioactivity in the Estuary

Mathematical simulation of sediment and contaminant transport in surface waters. Annual report, October 1977--September 1978

International Nuclear Information System (INIS)

Onishi, Y.; Arnold, E.M.; Serne, R.J.; Cowan, C.E.; Thompson, F.L.; Mayer, D.W.

1979-01-01

Various pathways exist for exposure of humans and biota to radioactive materials released from nuclear facilities. Hydrologic transport (liquid pathway) is one element in the evaluation of the total radiation dose to man. Mathematical models supported by well-planned field data collection programs can be useful tools in assessing the hydrologic transport and ultimate fate of radionuclides. Radionuclides with high distribution coefficients or radionuclides in surface waters with high suspended sediment concentrations are, to a great extent, adsorbed by river and marine sediments. Thus, otherwise dilute contaminants are concentrated. Contaminated sediments may be deposited on the river and ocean beds creating a significant pathway to man. Contaminated bed sediment in turn may become a long-term source of pollution through desorption and resuspension. In order to assess migration and accumulation of radionuclides in surface waters, mathematical models must correctly simulate essential mechanisms of radionuclide transport. The objectives of this study were: (1) to conduct a critical review of (a) radionuclide transport models as well as sediment transport and representative water quality models in rivers, estuaries, oceans, lakes, and reservoirs, and (b) adsorption and desorption mechanisms of radionuclides with sediments in surface waters; (2) to synthesize a mathematical model capable of predicting short- and long-term transport and accumulation of radionuclides in marine environments

Strippable gel for decontamination of contaminated metallic surfaces

International Nuclear Information System (INIS)

Banerjee, D.; Sandhya, U.; Khot, S.A.; Srinivas, C.; Wattal, P.K.

2013-01-01

Periodic decontamination of radioactive laboratories including fume hoods, glove boxes and all surfaces used for handling, processing and transporting radioactive materials is mandatory in all nuclear installations as this reduces spread of contamination and decreases total man rem exposure. Conventionally, chemical decontaminating agents or surfactant solutions are used for this purpose. However, this approach leads to generation of large volume of secondary radioactive waste. The use of strippable gel is an attractive alternative with low secondary waste generation particularly where removal of loose or weakly fixed contamination is necessary and also when the decontaminated material are to be reused, for e.g. decontamination of fume hoods, glove boxes, transport casks, spent fuel storage racks, control rod drive transport containers etc. Literature on gel formulations is scarce and mostly in the patent form. The sustained effort on gel formulation development has resulted in a basic gel formulation. The gel is a highly viscous water-based organic polymer, particularly suitable for application on vertical surfaces including difficult to reach metallic surfaces of complex geometry and not just limited to horizontal surfaces. The gel can be easily applied on contaminated surfaces by brushing or spraying. Curing of the gel is complete within 16-24 hours under ambient conditions and can then be removed by peeling as a dry sheet. While curing, the contaminants are trapped in gel either physically or chemically depending upon the nature of the contaminant. Salient features of cured gel include that it is water soluble and can be disposed off after immobilization in cement. Decontamination performance of the gel was initially evaluated by applying it on SS planchettes contaminated with known amount of radionuclides such as Cs(I), Co(II) and Ce(III). The measured decontamination factor was found to be in the range of 50-500, lowest for Ce(III) and highest for Co

Measurement and removal of surface contamination

International Nuclear Information System (INIS)

Neider, M.; Tamberg, T.

1990-01-01

This is a critical reappraisal of the sampling factor which is important for indirect contamination measurement. The factor gives the radioactivity collected by means of a wipe sample as a fraction of the total loose radioactivity i.e. without firm adhesion. It is used in national and international standard specifications and stated, frequently with excessive conservatism, as 0.1. Secondly, the standard specifications for the testing and appraisal of surface materials in relation to their decontamination capacity and for testing the effect of decontamination agents hitherto bond and Co-60 and Cs-137 are to be expanded to include radioactive iodine, which is important in nuclear medicine. The selection of optimum surface materials will thus be put on an improved basis. (orig./DG) [de

Method of electrolytic decontamination of contaminated metal materials for radioactivity

International Nuclear Information System (INIS)

Harada, Yoshio; Ishibashi, Masaru; Matsumoto, Hiroyo.

1985-01-01

Purpose: To electrolytically eliminate radioactive materials from metal materials contaminated with radioactive materials, as well as efficiently remove metal ions leached out in an electrolyte. Method: In the case of anodic dissolution of metal materials contaminated with radioactivity in an electrolyte to eliminate radioactive contaminating materials on the surface of the metal materials, a portion of an electrolytic cell is defined with partition membranes capable of permeating metal ions therethrough. A cathode connected to a different power source is disposed to the inside of the partition membranes and fine particle of metals are suspended and floated in the electrolyte. By supplying an electric current between an insoluble anode disposed outside of the partition membranes and the cathode, metal ions permeating from the outside of the partition membranes are deposited on the fine metal particles. Accordingly, since metal ions in the electrolyte are removed, the electrolyte can always be kept clean. (Yoshihara, H.)

Evaluation of Unfixed Tritium Surface Contamination

International Nuclear Information System (INIS)

Postolache, C.; Matei, Lidia

2005-01-01

Surface unfixed radioactive contamination represents the amount of surface total radioactive contamination which can be eliminated by pure mechanical processes. This unfixed contamination represents the main risk factor for contamination of the personnel which operates in tritium laboratories. Unfixed contamination was determined using sampling smears type FPCSN-PSE-AA. Those FPCSN-PSE-AA smears are disks of expanded polystyrene which contain acrylic acid fragments superficially grafted. Sampling factor was determinated by contaminated surface wiping with moisten smears in 50 μL butylic alcohol and activity measuring at liquid scintillation measuring device. Sampling factor was determined by the ratio between measured activity and initially real conventional activity. The sampling factor was determined for Tritium Laboratory existent surfaces: stainless steel, aluminum, glass, ceramics, linoleum, washable coats, epoxy resins type ALOREX LP-52.The sampling factors and the reproducibility were determined in function of surface nature

Functionalized mesoporous materials for adsorption and release of different drug molecules: A comparative study

International Nuclear Information System (INIS)

Wang Gang; Otuonye, Amy N.; Blair, Elizabeth A.; Denton, Kelley; Tao Zhimin; Asefa, Tewodros

2009-01-01

The adsorption capacity and release properties of mesoporous materials for drug molecules can be improved by functionalizing their surfaces with judiciously chosen organic groups. Functionalized ordered mesoporous materials containing various types of organic groups via a co-condensation synthetic method from 15% organosilane and by post-grafting organosilanes onto a pre-made mesoporous silica were synthesized. Comparative studies of their adsorption and release properties for various model drug molecules were then conducted. Functional groups including 3-aminopropyl, 3-mercaptopropyl, vinyl, and secondary amine groups were used to functionalize the mesoporous materials while rhodamine 6G and ibuprofen were utilized to investigate the materials' relative adsorption and release properties. The self-assembly of the mesoporous materials was carried out in the presence of cetyltrimethylammonium bromide (CTAB) surfactant, which produced MCM-41 type materials with pore diameters of ∼2.7-3.3 nm and moderate to high surface areas up to ∼1000 m 2 /g. The different functional groups introduced into the materials dictated their adsorption capacity and release properties. While mercaptopropyl and vinyl functionalized samples showed high adsorption capacity for rhodamine 6G, amine functionalized samples exhibited higher adsorption capacity for ibuprofen. While the diffusional release of ibuprofen was fitted on the Fickian diffusion model, the release of rhodamine 6G followed Super Case-II transport model. - Graphical abstract: The adsorption capacity and release properties of mesoporous materials for various drug molecules are tuned by functionalizing the surfaces of the materials with judiciously chosen organic groups. This work reports comparative studies of the adsorption and release properties of functionalized ordered mesoporous materials containing different hydrophobic and hydrophilic groups that are synthesized via a co-condensation and post-grafting methods for

Removal of Microbial Contamination from Surface by Plasma

Science.gov (United States)

Feng, Xinxin; Liu, Hongxia; Shen, Zhenxing; Wang, Taobo

2018-01-01

Microbial contamination is closely associated with human and environmental health, they can be tested on food surfaces, medical devices, packing material and so on. In this paper the removal of the microbial contamination from surface using plasma treatment is investigated. The Escherichia coli (E. coli) has been chosen as a bio-indicator enabling to evaluate the effect of plasma assisted microbial inactivation. Oxygen gas was as the working gas. The plasma RF power, plasma exposition time, gas flow and the concentration of organic pollutant were varied in order to see the effect of the plasma treatment on the Gram-negative germ removal. After the treatment, the microbial abatement was evaluated by the standard plate count method. This proved a positive effect of the plasma treatment on Gram-negative germ removal. The kinetics and mathematical model of removal were studied after plasma treatment, and then the removing course of E. coli was analyzed. This work is meaningful for deepening our understanding of the fundamental scientific principles regarding microbial contamination from surface by plasma.

Tritium surface loading due to contamination of rainwater from atmospheric release at NAPS

International Nuclear Information System (INIS)

Sharma, L.N.; Dube, B.; Varakhedkar, V.K.

2001-01-01

Annual tritium (HTO) surface loading has been measured and calculated for the year 1998-99 within 0.8 km distance from 145m high stack of Narora Atomic Power Station (NAPS) at eight locations in different directions. The technique for measured values consists of the summation of product of tritium concentration (Bq/l) in daily rainfall samples and daily rainfall (mm) whereas that for calculated values having the use of prevailing meteorological conditions and average tritium release rate during a year. The ratios of measured and calculated values of tritium surface loading during the years 1998-99 are found to be in the range of 0.18 to 6.97. Tritium surface loading studies at NAPS reveal that a fraction 1.7E-03 of total annual tritium released through stack gets deposited on the surface due to washout / rainout of plume within 0.8 km radial distance from stack. The range of deposition velocity, V w (m.s - 1 ) i.e the ratio of annual tritium surface loading W(Bq.m - 2 . s - 1 ) and annual mean tritium concentration in air, χo(Bq.m - 3) at three locations for the years 1998-99 is found to be 5.59E-04 to 5.99E-03 ms - 1 . The average value for wet deposition velocity V bar w for NAPS site is estimated as 2.92E-03 m.s - 1. (author)

Nanostructured Diclofenac Sodium Releasing Material

Science.gov (United States)

Nikkola, L.; Vapalahti, K.; Harlin, A.; Seppälä, J.; Ashammakhi, N.

2008-02-01

Various techniques have been developed to produce second generation biomaterials for tissue repair. These include extrusion, molding, salt leaching, spinning etc, but success in regenerating tissues has been limited. It is important to develop porous material, yet with a fibrous structure for it to be biomimetic. To mimic biological tissues, the extra-cellular matrix usually contains fibers in nano scale. To produce nanostructures, self-assembly or electrospinning can be used. Adding a drug release function to such a material may advance applications further for use in controlled tissue repair. This turns the resulting device into a multifunctional porous, fibrous structure to support cells and drug releasing properties in order to control tissue reactions. A bioabsorbable poly(ɛ-caprolactone-co-D,L lactide) 95/5 (PCL) was made into diluted solution using a solvent, to which was added 2w-% of diclofenac sodium (DS). Nano-fibers were made by electrospinning onto substrate. Microstructure of the resulting nanomat was studied using SEM and drug release profiles with UV/VIS spectroscopy. Thickness of the electrospun nanomat was about 2 mm. SEM analysis showed that polymeric nano-fibers containing drug particles form a highly interconnected porous nano structure. Average diameter of the nano-fibers was 130 nm. There was a high burst peak in drug release, which decreased to low levels after one day. The used polymer has slow a degradation rate and though the nanomat was highly porous with a large surface area, drug release rate is slow. It is feasible to develop a nano-fibrous porous structure of bioabsorbable polymer, which is loaded with test drug. Drug release is targeted at improving the properties of biomaterial for use in controlled tissue repair and regeneration.

Development of inspection techniques for quantitatively measuring surface contamination on SRM hardware

Science.gov (United States)

Law, R. D.

1989-01-01

A contaminant is any material or substance which is potentially undesirable or which may adversely affect any part, component, or assembly. Contamination control of SRM hardware surfaces is a serious concern, for both Thiokol and NASA, with particular concern for contaminants which may adversely affect bonding surfaces. The purpose of this study is to develop laboratory analytical techniques which will make it possible to certify the cleanliness of any designated surface, with special focus on particulates (dust, dirt, lint, etc.), oils (hydrocarbons, silicones, plasticizers, etc.), and greases (HD-2, fluorocarbon grease, etc.). The hardware surfaces of concern will include D6AC steel, aluminum alloys, anodized aluminum alloys, glass/phenolic, carbon/phenolic, NBR/asbestos-silica, and EPDM rubber.

Admixture enhanced controlled low-strength material for direct underwater injection with minimal cross-contamination

International Nuclear Information System (INIS)

Hepworth, H.K.; Davidson, J.S.; Hooyman, J.L.

1997-01-01

Commercially available admixtures have been developed for placing traditional concrete products under water. This paper evaluates adapting anti-washout admixture (AWA) and high range water reducing admixture (HRWRA) products to enhance controlled low-strength materials (CLSMs) for underwater placement. A simple experimental scale model (based on dynamic and geometric similitude) of typical grout pump emplacement equipment has been developed to determine the percentage of cementing material washed out. The objective of this study was to identify proportions of admixtures and underwater CLSM emplacement procedures which would minimize the cross-contamination of the displaced water while maintaining the advantages of CLSM. Since the displaced water from radioactively contaminated systems must be subsequently treated prior to release to the environment, the amount of cross-contamination is important for cases in which cementing material could form hard sludges in a water treatment facility and contaminate the in-place CLSM stabilization medium

Development of an automatic smear sampler and evaluation of surface contamination

International Nuclear Information System (INIS)

Seo, B. K.; Lee, B. J.; Lee, K. W.; Park, J. H.

2004-01-01

The surface contamination level of a radiation-controlled area is measured periodically according to atomic energy law and connection regulations. The measurement of surface contamination by an indirect method is subject to various kinds of error depending on the sampling person and consumes much time and effort in the sampling of large nuclear facilities. In this research, an automatic smear sampler is developed to solve these problems. The developed equipment is composed of a rotating sampling part, a sample transferring part, a power supply part a control part, and vacuum part. It improved the efficiency of estimation of the surface contamination level achieved periodically in a radiation-controlled area. Using an automatic smear sampler developed in this research, it is confirmed that radioactive contaminated materials are uniformly transferred to smear paper more than any sampling method by an operator. (authors)

Ice-Release and Erosion Resistant Materials for Wind Turbines

Science.gov (United States)

Zhang, Wei; Brinn, Cameron; Cook, Alex; Pascual-Marquez, Fernando

2017-11-01

Icing conditions may cause wind turbine generators to partially lose productivity or to be completely shut down to avoid structural damage. At present, commercially available technologies to mitigate this problem consist of expensive, energy hungry heating elements, which costs roughly 70,000 euro per medium size turbine. Conventional passive ice protection coating systems heavily rely on delicate surface structures and expensive materials to create water repellent superhydrophobic / low surface energy surfaces, which have been proven to be ineffective against ice accumulation. The lack of performance among conventional ice protection materials stems from a flaw in the approach to the problem: failure to recognize that water in its liquid form (WATER) and water in its solid form (ICE) are two different things. Something that works for WATER does not automatically work for ICE. Another reason is that many superhydrophobic materials are often reliant upon often fragile micro-structured surfaces to achieve their intended effects. This paper discusses a fundamentally different approach to the creation of a robust, low cost, durable, and multifunctional materials for ice release and erosion resistance. This National Science Foundation sponsored ice-release coating technology holds promise for protecting wind turbine blades and towers, thus potentially increasing reliability for power generation under icing conditions. Because of the vulnerability of wind turbine blades to ice buildup and erosion damages, wind farm facilities stand to reap considerable benefits.

Molecular-level removal of proteinaceous contamination from model surfaces and biomedical device materials by air plasma treatment.

Science.gov (United States)

Banerjee, K K; Kumar, S; Bremmell, K E; Griesser, H J

2010-11-01

Established methods for cleaning and sterilising biomedical devices may achieve removal of bioburden only at the macroscopic level while leaving behind molecular levels of contamination (mainly proteinaceous). This is of particular concern if the residue might contain prions. We investigated at the molecular level the removal of model and real-life proteinaceous contamination from model and practical surfaces by air plasma (ionised air) treatment. The surface-sensitive technique of X-ray photoelectron spectroscopy (XPS) was used to assess the removal of proteinaceous contamination, with the nitrogen (N1s) photoelectron signal as its marker. Model proteinaceous contamination (bovine serum albumin) adsorbed on to a model surface (silicon wafer) and the residual proteinaceous contamination resulting from incubating surgical stainless steel (a practical biomaterial) in whole human blood exhibited strong N1s signals [16.8 and 18.5 atomic percent (at.%), respectively] after thorough washing. After 5min air plasma treatment, XPS detected no nitrogen on the sample surfaces, indicating complete removal of proteinaceous contamination, down to the estimated XPS detection limit 10ng/cm(2). Applying the same plasma treatment, the 7.7at.% nitrogen observed on a clinically cleaned dental bur was reduced to a level reflective of new, as-received burs. Contact angle measurements and atomic force microscopy also indicated complete molecular-level removal of the proteinaceous contamination upon air plasma treatment. This study demonstrates the effectiveness of air plasma treatment for removing proteinaceous contamination from both model and practical surfaces and offers a method for ensuring that no molecular residual contamination such as prions is transferred upon re-use of surgical and dental instruments. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

Release process for non-real property containing residual radioactive material

International Nuclear Information System (INIS)

Ranek, N.L.; Chen, S.Y.; Kamboj, S.; Hensley, J.; Burns, D.; Fleming, R.; Warren, S.; Wallo, A.

1997-01-01

It is DOE's objective to operate its facilities and to conduct its activities so that radiation exposures to members of the public are maintained within acceptable limits and exposures to residual radioactive materials are controlled. To accomplish this, DOE has adopted Order DOE 5400.51 'Radiation Protection of the Public and the Environment', and will be promulgating IO CR Part 834 to codify and clarify the requirements of DOE 5400.5. Under both DOE 5400.5 and 10 CR Part 834, radioactively contaminated DOE property is prohibited from release unless specific actions have been completed prior to the release. This paper outlines a ten-step process that, if followed, will assist DOE Operations and contractor personnel in ensuring that the required actions established by Order DOE 5400.5 and 10 CR Part 834 have been appropriately completed prior to the release for reuse or recycle of non-real property (e.g., office furniture, computers, hand tools, machinery, vehicles and scrap metal). Following the process will assist in ensuring that radiological doses to the public from the released materials will meet applicable regulatory standards and be as low as reasonably achievable (ALARA)

Standard Guide for Unrestricted Disposition of Bulk Materials Containing Residual Amounts of Radioactivity

CERN Document Server

American Society for Testing and Materials. Philadelphia

2009-01-01

1.1 This guide covers the techniques for obtaining approval for release of materials encountered in decontamination and decommissioning (D&D) from restricted use. This would be addressed in the decommissioning plan (E 1281). It applies to materials that do not meet any of the requirements for regulatory control because of radioactivity content. Fig. 1 shows the logic diagram for determining the materials that could be considered for release. Materials that negotiate this logic tree are referred to as “candidate for release based on dose.” 1.2 The objective of this guide is to provide a methodology for distinguishing between material that must be carefully isolated to prevent human contact from that that can be recycled or otherwise disposed of. It applies to material in which the radioactivity is dispersed more or less uniformly throughout the volume of the material (termed residual in bulk form) as opposed to surface contaminated objects. 1.3 Surface contaminated objects are materials externally co...

Fluoride release and surface roughness of a new glass ionomer cement: glass carbomer

Directory of Open Access Journals (Sweden)

Célia Maria Condeixa de França LOPES

2018-02-01

Full Text Available Abstract Objective This study analyzed the fluoride release/recharge and surface roughness of glass carbomer compared to other encapsulated glass ionomer cements (GICs. Material and method The GICs tested were Glass Fill® (GC-GCP Dental, Riva Self Cure® (RS-SDI, Riva Light Cure® (RL-SDI, Equia Fil® (EF-GC Europe. The composite resin Luna® (LU-SDI was used as control. Five samples of each material were prepared and kept in a humidifier for 24 hours (37 °C, 100% relative humidity. Fluoride release was measured in two times: before (T1: days 1, 2, 7, 14 and after topical application of fluoride (T2: days 15, 16, 21 and 28. The surface roughness was also measured in both times (T1: days 1 and 14; T2: days 15 and 28. All samples were submitted to a single topical application of acidulated fluoride phosphate (Fluor Care - FGM. Two-way ANOVA with repeated measures and Tukey's post-test (p <0.05 were used in the statistical analysis. Result Equia Fil presented the highest fluoride release in both evaluation periods, with a higher release in T1 (p <0.05. The other materials tested, including glass carbomer presented similar release in both periods (T1 and T2. Regarding surface roughness, no significant differences were observed in the interaction between the material × time factors (T1 and T2 (p=0.966. Conclusion The GICs tested presented fluoride release and recharge ability and showed no surface roughness increase by topical application of fluoride.

Response to a radioactive materials release having a transboundary impact

International Nuclear Information System (INIS)

1989-01-01

Compared with an accidental release of radioactive material which is confined to the accident State, a transboundary release has added dimensions which were not fully anticipated in publications dealing with response to accidents at nuclear facilities. The new aspects to the problem may be summarized as follows: (1) A transboundary release of radioactive material, as distinct from a release which affects only the accident State, has international repercussions in the following ways: Potentially at least, the difficulties associated with a transboundary release may be magnified in those States that have no nuclear facilities of their own and may, therefore, have foreseen no need for resources to assess and deal with radioactive contamination of their food supplies, their water and their environment appropriately. International trade, in food commodities particularly, may be severely affected. Issues of compensation may arise for which the dispute settlement mechanisms are weak or non-existent. (2) Many Member States are in such geographic locations that they could be affected by a transboundary release occurring in any of their surrounding neighbour States. Planning for and responding to such an event is necessarily more difficult than planning for an accidental release from a single, identified nuclear facility. (3) Deposits of radioactive material from a distant source are apt to be highly unpredictable. Depending on weather conditions, they may be localized in a random fashion or widespread. Because of the international dimension of the problem and its essentially unpredictable character it is recommended here that planning for such events should be carried at the national or federal government level rather than at provincial government level. 14 refs

Simulated atmospheric disperison of radioactive material released in an urban area

International Nuclear Information System (INIS)

Akins, R.E.; Church, H.W.; Tierney, M.S.

1977-01-01

A combination of Gaussian plume and particle-in-cell techniques is used to simulate the atmospheric transport and dispersion of a puff release of radioactive material. The release is caused by an accident that is assumed to occur during the shipment of the radioactive material through central New York City. The simulation provides estimates of volumetric and surface concentrations of the dispersed material that are used to predict radiation doses incurred by the City's population in the event of an accidental release. In the simulation, the release point is arbitrary and the material is assumed to be either a gas or fine particles. The Gaussian plume model follows cloud concentrations from the release time until times when transport over distances up to 500 m has been achieved. The released cloud may stabilize at street level or above the mean buildings height; at a street intersection or in the middle of the block. The possibility of the formation of multiple clouds, owing to circumstances of wind flow direction and street geometry, is allowed

Pure and Oxidized Copper Materials as Potential Antimicrobial Surfaces for Spaceflight Activities

Science.gov (United States)

Hahn, C.; Hans, M.; Hein, C.; Mancinelli, R. L.; Mücklich, F.; Wirth, R.; Rettberg, P.; Hellweg, C. E.; Moeller, R.

2017-12-01

Microbial biofilms can lead to persistent infections and degrade a variety of materials, and they are notorious for their persistence and resistance to eradication. During long-duration space missions, microbial biofilms present a danger to crew health and spacecraft integrity. The use of antimicrobial surfaces provides an alternative strategy for inhibiting microbial growth and biofilm formation to conventional cleaning procedures and the use of disinfectants. Antimicrobial surfaces contain organic or inorganic compounds, such as antimicrobial peptides or copper and silver, that inhibit microbial growth. The efficacy of wetted oxidized copper layers and pure copper surfaces as antimicrobial agents was tested by applying cultures of Escherichia coli and Staphylococcus cohnii to these metallic surfaces. Stainless steel surfaces were used as non-inhibitory control surfaces. The production of reactive oxygen species and membrane damage increased rapidly within 1 h of exposure on pure copper surfaces, but the effect on cell survival was negligible even after 2 h of exposure. However, longer exposure times of up to 4 h led to a rapid decrease in cell survival, whereby the survival of cells was additionally dependent on the exposed cell density. Finally, the release of metal ions was determined to identify a possible correlation between copper ions in suspension and cell survival. These measurements indicated a steady increase of free copper ions, which were released indirectly by cells presumably through excreted complexing agents. These data indicate that the application of antimicrobial surfaces in spaceflight facilities could improve crew health and mitigate material damage caused by microbial contamination and biofilm formation. Furthermore, the results of this study indicate that cuprous oxide layers were superior to pure copper surfaces related to the antimicrobial effect and that cell density is a significant factor that influences the time dependence of

Maximum permissible dietary contamination after the accidental release of radioactive materials from a nuclear reactor

Energy Technology Data Exchange (ETDEWEB)

Pochin, E E; Rock Carling, Ernest; Court Brown, W M [Medical Research Council, Committee on Protection against Ionizing Radiations, London (United Kingdom); and others

1960-12-01

After the accident to No. 1 pile at Windscale on October 10, 1957 (Atomic Energy Office, 1957), the Atomic Energy Authority asked the Medical Research Council for advice on the maximum intake of certain radioactive isotopes that should be regarded as permissible, under emergency conditions, for members of the general population living in, or deriving food from, an area contaminated owing to an accident to a reactor. The Council's Committee on Protection against Ionizing Radiations, together with its Subcommittees on Internal and External Radiations, has considered this problem, and concludes that the intake of radioactive materials by ingestion of contaminated food would generally be the limiting source of hazard after any such accident. Intake by inhalation, or radiation from the exterior, would become of importance only in rather special circumstances. In the following report, therefore, the Committee proposes maximum permissible levels of dietary contamination for the relevant isotopes in the emergency conditions envisaged. In proposing these levels, the Protection Committee has used the fullest information available on the radiation doses that would be delivered to different body tissues and at different ages by the isotopes concerned, and on the ways in which these materials would enter the body.

Maximum permissible dietary contamination after the accidental release of radioactive materials from a nuclear reactor

International Nuclear Information System (INIS)

Pochin, E.E.; Rock Carling, Ernest; Court Brown, W.M.

1960-01-01

After the accident to No. 1 pile at Windscale on October 10, 1957 (Atomic Energy Office, 1957), the Atomic Energy Authority asked the Medical Research Council for advice on the maximum intake of certain radioactive isotopes that should be regarded as permissible, under emergency conditions, for members of the general population living in, or deriving food from, an area contaminated owing to an accident to a reactor. The Council's Committee on Protection against Ionizing Radiations, together with its Subcommittees on Internal and External Radiations, has considered this problem, and concludes that the intake of radioactive materials by ingestion of contaminated food would generally be the limiting source of hazard after any such accident. Intake by inhalation, or radiation from the exterior, would become of importance only in rather special circumstances. In the following report, therefore, the Committee proposes maximum permissible levels of dietary contamination for the relevant isotopes in the emergency conditions envisaged. In proposing these levels, the Protection Committee has used the fullest information available on the radiation doses that would be delivered to different body tissues and at different ages by the isotopes concerned, and on the ways in which these materials would enter the body

The inhalation of radioactive materials as related to hand contamination

Energy Technology Data Exchange (ETDEWEB)

Bailey, J.C.; Rohr, R.C.

1953-09-15

Tests performed to determine the hazard associated with the inhalation of radioactive materials as the result of smoking with contaminated hands indicate that for dry uranium compounds adhering to the palmar surfaces of the hands, approximately 1.0% of the material may be transferred to a cigarette, and that of this approximately 0.2% may appear in the smoke which is inhaled. Most of the contamination originally placed in a cigarette was found in the ash, and only 11% of the material was not recovered following burning; approximately half of this loss may be attributed to normal losses inherent in the analytical process, the recovery efficiency for which was found by supplementary experiments to be 95%.

Experimental study on source efficiencies for estimating surface contamination level

International Nuclear Information System (INIS)

Ichiji, Takeshi; Ogino, Haruyuki

2008-01-01

Source efficiency was measured experimentally for various materials, such as metals, nonmetals, flooring materials, sheet materials and other materials, contaminated by alpha and beta emitter radioactive nuclides. Five nuclides, 147 Pm, 60 Co, 137 Cs, 204 Tl and 90 Sr- 90 Y, were used as the beta emitters, and one nuclide 241 Am was used as the alpha emitter. The test samples were prepared by placing drops of the radioactive standardized solutions uniformly on the various materials using an automatic quantitative dispenser system from Musashi Engineering, Inc. After placing drops of the radioactive standardized solutions, the test materials were allowed to dry for more than 12 hours in a draft chamber with a hood. The radioactivity of each test material was about 30 Bq. Beta rays or alpha rays from the test materials were measured with a 2-pi gas flow proportional counter from Aloka Co., Ltd. The source efficiencies of the metals, nonmetals and sheet materials were higher than 0.5 in the case of contamination by the 137 Cs, 204 Tl and 90 Sr- 90 Y radioactive standardized solutions, higher than 0.4 in the case of contamination by the 60 Co radioactive standardized solution, and higher than 0.25 in the case of contamination by the alpha emitter the 241 Am radioactive standardized solution. These values were higher than those given in Japanese Industrial Standards (JIS) documents. In contrast, the source efficiencies of some permeable materials were lower than those given in JIS documents, because source efficiency varies depending on whether the materials or radioactive sources are wet or dry. This study provides basic data on source efficiency, which is useful for estimating the surface contamination level of materials. (author)

Effective decolorization and adsorption of contaminant from industrial dye effluents using spherical surfaced magnetic (Fe_3O_4) nanoparticles

International Nuclear Information System (INIS)

Suriyaprabha, R.; Khan, Samreen Heena; Pathak, Bhawana; Fulekar, M. H.

2016-01-01

Treatment of highly concentrated Industrial dye stuff effluents released in the environment is the major issue faced in the era of waste management as well as in water pollution. Though there is availability of conventional techniques in large numbers, there is a need of efficient and effective advance technologies. In account of that, Nanotechnology plays a prominent role to treat the heavy metals, organic and inorganic contaminants using smart materials in nano regime (1 -100 nm). Among these nanomaterials like Iron Oxide (Fe_3O_4, magnetic nanoparticle) is one of the most promising candidates to remove the heavy metals from the industrial effluent. Fe_3O_4 is the widely used smart material with magnetic property having high surface area; high surface to volume ratio provides more surface for the chemical reaction for the surface adsorption. Fe_3O_4 nanoparticles have been synthesized using sonochemical method using ultra frequency in aqueous solution under optimized conditions. The as-synthesized nanoparticle was analyzed using different characterization tool. The Transmission Electron microscope (TEM) images revealed 10-12 nm spherical shape nanoparticles; crystal phase and surface morphology was confirmed by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM), respectively. The functional group were identified by Fourier Transform-Infra Red Spectroscopy (FT-IR), revealed the bending and stretching vibrations associated with Iron Oxide nanoparticle. In present study, for the efficient removal of contaminants, different concentration (10-50 ppm) of dye stuff effluent has been prepared and subjected to adsorption and decolourization at definite time intervals with Fe_3O_4 nanoparticles. The concentration of Iron oxide and the time (45 mins) was kept fixed for the reaction whereas the concentration of dye stuff effluent was kept varying. It was found that the spherical shaped Fe_3O_4 proved to be the potential material for the adsorption of

Fundamental study of polonium contamination by neutron irradiated lead-bismuth eutectic

International Nuclear Information System (INIS)

Obara, T.; Miura, T.; Sekimoto, H.

2005-01-01

As a fundamental study of polonium contamination by neutron irradiated LBE, it was investigated to remove polonium surface contamination by baking method. The baking experiments were performed using quartz glass plates contaminated by material evaporated from neutron irradiated LBE liquid. The contaminated quartz glass plates were baked in vacuum (2 Pa) at various temperatures. The experimental results clearly show that polonium evaporated from LBE can be removed by baking samples at temperatures 300 deg. C and above. It is of note that the decrease in the weight of deposited materials baked at 300 deg. C differed from that observed at 400 deg. C or higher temperatures. At temperature of 300 deg. C, no change in weight was observed. The mass of polonium in the LBE samples was so small that no weight change could be observed by release of polonium. Thus, it might show that only the polonium among the adherent materials was removed by baking at 300 deg. C without removing other adhered material. The method is rather simple, so it is easy to apply the method for practical application. One of the expected applications may be the removal of polonium contamination in a primary loop before maintenance work of the loop. Also it shows that this method can be used to avoid the release of polonium from contaminated material, in case of an accident, by keeping the contaminated material at low temperature

Characterisation of Plasma Vitrified Simulant Plutonium Contaminated Material Waste

International Nuclear Information System (INIS)

Hyatt, Neil C.; Morgan, Suzy; Stennett, Martin C.; Scales, Charlie R.; Deegan, David

2007-01-01

The potential of plasma vitrification for the treatment of a simulant Plutonium Contaminated Material (PCM) was investigated. It was demonstrated that the PuO 2 simulant, CeO 2 , could be vitrified in the amorphous calcium iron aluminosilicate component of the product slag with simultaneous destruction of the organic and polymer waste fractions. Product Consistency Tests conducted at 90 deg. C in de-ionised water and buffered pH 11 solution show the PCM slag product to be durable with respect to release of Ce. (authors)

Aluminum-contaminant transport by surface runoff and bypass flow from an acid sulphate soil

NARCIS (Netherlands)

Minh, L.Q.; Tuong, T.P.; Mensvoort, van M.E.F.; Bouma, J.

2002-01-01

Quantifying the process and the amount of acid-contaminant released to the surroundings is important in assessing the environmental hazards associated with reclaiming acid sulphate soils (ASS). The roles of surface runoff and bypass flow (i.e. the rapid downward flow of free water along macropores

Some problems in calibrating surface contamination meters

International Nuclear Information System (INIS)

Chen Zigen; LI Xingyuan; Shuai Xiaoping.

1984-01-01

It is necessary that instruments are calibrated accurately in order to obtain reliable survey data of surface contamination. Some problems in calibrating surface contamination meters are expounded in this paper. Measurement comparison for beta surface contamination meters is organized within limited scope, thus survey quality is understood, questions are discovered, significance of calibration is expounded further. (Author)

Radiological protection principles concerning the safeguard, use or release of contaminated materials, buildings, areas or dumps from uranium mining. Recommendations of the Commission on Radiological Protection with explanations

International Nuclear Information System (INIS)

Mueller-Neumann, M.

1992-01-01

The volume presents the full texts of the SSK Recommendations addressing the aspects and problems involved, and which can be separately retrieved from the database: 1) Radiological protection principles concerning the release of scrap from the shut-down of uranium mining plants; 2) Radiological protection principles concerning the release for industrial use of areas contaminated from uranium mining; 3) Radiological protection principles concerning the use for forest and agricultural purposes and as public gardens (parks) and residential areas of areas contaminated from uranium mining; 4) Radiological protection principles concerning the safeguard and use of mine dumps; 5) Radiological protection principles concerning the release for further commercial or industrial use of buildings used for commercial or industrial purposes and the disposal of building debris from uranium mining and milling; 6) Radiological protection principles concerning the release for general use of reusable equipment and installations from uranium mining. The following appendices round up the material: 1) Radiation exposure from mining in Saxony and Thuringia and its evaluation (Summary of the results of consultations during the 1990 closed meeting); 2) Radiological protection principles for the limitation of the radiation exposure of the public to radon and its daughters; 3) Epidemiological studies on the health state of the inhabitants of the mining region and the miners in Saxony and Thuringia. (orig.) [de

"Effect of nano-filled surface coating agent on fluoride release from conventional glass ionomer cement: An in vitro trial"

OpenAIRE

S Tiwari; B Nandlal

2013-01-01

Context: To overcome the drawbacks of glass ionomer cement of sensitivity to initial desiccation and moisture contamination the use of surface coating agent is recommended. The search in this area led to invent of use of nanofillers in surface coating agent, but its effect on fluoride release is not clear. Aim: The aim of this study is to evaluate and compare the fluoride release from conventional glass ionomer cement with and without surface coating agent. Settings and Design: This in vitro ...

Impacts of soil petroleum contamination on nutrient release during litter decomposition of Hippophae rhamnoides.

Science.gov (United States)

Zhang, Xiaoxi; Liu, Zengwen; Luc, Nhu Trung; Yu, Qi; Liu, Xiaobo; Liang, Xiao

2016-03-01

Petroleum exploitation causes contamination of shrub lands close to oil wells. Soil petroleum contamination affects nutrient release during the litter decomposition of shrubs, which influences nutrient recycling and the maintenance of soil fertility. Hence, this contamination may reduce the long-term growth and stability of shrub communities and consequently, the effects of phytoremediation. Fresh foliar litter of Hippophae rhamnoides, a potential phytoremediating species, was collected for this study. The litter was placed in litterbags and then buried in different petroleum-polluted soil media (the petroleum concentrations were 15, 30, and 45 g kg(-1) dry soil, which were considered as slightly, moderately and seriously polluted soil, respectively) for a decomposition test. The impacts of petroleum contamination on the release of nutrients (including N, P, K, Cu, Zn, Fe, Mn, Ca and Mg) were assessed. The results showed that (1) after one year of decomposition, the release of all nutrients was accelerated in the slightly polluted soil. In the moderately polluted soil, P release was accelerated, while Cu, Zn and Mn release was inhibited. In the seriously polluted soil, Cu and Zn release was accelerated, while the release of the other nutrients was inhibited. (2) The effect of petroleum on nutrient release from litter differed in different periods during decomposition; this was mainly due to changes in soil microorganisms and enzymes under the stress of petroleum contamination. (3) To maintain the nutrient cycling and the soil fertility of shrub lands, H. rhamnoides is only suitable for phytoremediation of soils containing less than 30 g kg(-1) of petroleum.

Fuel Oxidizer Reaction Products (FORP) Contamination of Service Module (SM) and Release of N-nitrosodimethylamine(NDMA)in a Humid Environment from Crew EVA Suits Contaminated with FORP

Science.gov (United States)

Schmidl, William; Mikatarian, Ron; Lam, Chiu-Wing; West, Bil; Buchanan, Vanessa; Dee, Louis; Baker, David; Koontz, Steve

2004-01-01

The Service Module (SM) is an element of the Russian Segment of the International Space Station (ISS). One of the functions of the SM is to provide attitude control for the ISS using thrusters when the U.S. Control Moment Gyros (CMG's) must be desaturated. Prior to an Extravehicular Activity (EVA) on the Russian Segment, the Docking Compartment (DC1) is depressurized, as it is used as an airlock. When the DC1 is depressurized, the CMG's margin of momentum is insufficient and the SM attitude control thrusters need to fire to desaturate the CMG's. SM roll thruster firings induce contamination onto adjacent surfaces with Fuel Oxidizer Reaction Products (FORP). FORP is composed of both volatile and non-volatile components. One of the components of FORP is the potent carcinogen N-nitrosdimethylamine (NDMA). Since the EVA crewmembers often enter the area surrounding the thrusters for tasks on the aft end of the SM and when translating to other areas of the Russian Segment, the presence of FORP is a concern. This paper will discuss FORP contamination of the SM surfaces, the release of NDMA in a humid environment from crew EVA suits, if they happen to be contaminated with FORP, and the toxicological risk associated with the NDMA release.

Atmospheric pressure plasma cleaning of contamination surfaces. 1997 mid-year progress report

International Nuclear Information System (INIS)

Hicks, R.; Selwyn, G.S.

1997-01-01

'Goals of the project are to (1) identify the key physics and chemistry underlying the use of high pressure plasmas for etching removal of actinides and actinide surrogates; and (2) identify key surface reactions and plasma physics necessary for optimization of the atmospheric pressure plasma jet. Technical description of the work decommissioning of transuranic waste (TRU) into low-level radioactive waste (LLW) represents the largest cleanup cost associated with the nuclear weapons complex. This work is directed towards developing a low-cost plasma technology capable of converting TRU into LLW, based upon highly selective plasma etching of plutonium and other actinides from contaminated surfaces. In this way, only the actinide material is removed, leaving the surface less contaminated. The plasma etches actinide material by producing a volatile halide compound, which may be efficiently trapped using filters. To achieve practical, low-cost operation of a plasma capable of etching actinide materials, the authors have developed a y-mode, resonant-cavity, atmospheric pressure plasma jet (APPJ). In contrast to conventional, low pressure plasmas, the APPJ produces a purely-chemical effluent free of ions, and so achieves very high selectivity and produces negligible damage to the surface. Since the jet operates outside a chamber, many nuclear wastes may be treated including machinery, duct-work, concrete and other building materials. In some cases, it may be necessary to first remove paint from contaminated surfaces using a plasma selective for that surface, then to switch to the actinide etching chemistry for removal of actinide contamination. The goal of this work is to develop the underlying science required for maturation of this technology and to establish early version engineering prototypes. Accomplishments to Date The authors have made significant progress in this program. The work conducted jointly at Los Alamos and at UCLA. This has been facilitated by exchange

Atmospheric pressure plasma cleaning of contamination surfaces. 1997 mid-year progress report

Energy Technology Data Exchange (ETDEWEB)

Selwyn, G.S. [Los Alamos National Lab., NM (US); Hicks, R. [Univ. of California, Los Angeles, CA (US)

1997-06-01

'Goals of the project are to (1) identify the key physics and chemistry underlying the use of high pressure plasmas for etching removal of actinides and actinide surrogates; and (2) identify key surface reactions and plasma physics necessary for optimization of the atmospheric pressure plasma jet. Technical description of the work decommissioning of transuranic waste (TRU) into low-level radioactive waste (LLW) represents the largest cleanup cost associated with the nuclear weapons complex. This work is directed towards developing a low-cost plasma technology capable of converting TRU into LLW, based upon highly selective plasma etching of plutonium and other actinides from contaminated surfaces. In this way, only the actinide material is removed, leaving the surface less contaminated. The plasma etches actinide material by producing a volatile halide compound, which may be efficiently trapped using filters. To achieve practical, low-cost operation of a plasma capable of etching actinide materials, the authors have developed a y-mode, resonant-cavity, atmospheric pressure plasma jet (APPJ). In contrast to conventional, low pressure plasmas, the APPJ produces a purely-chemical effluent free of ions, and so achieves very high selectivity and produces negligible damage to the surface. Since the jet operates outside a chamber, many nuclear wastes may be treated including machinery, duct-work, concrete and other building materials. In some cases, it may be necessary to first remove paint from contaminated surfaces using a plasma selective for that surface, then to switch to the actinide etching chemistry for removal of actinide contamination. The goal of this work is to develop the underlying science required for maturation of this technology and to establish early version engineering prototypes. Accomplishments to Date The authors have made significant progress in this program. The work conducted jointly at Los Alamos and at UCLA. This has been facilitated by

Enantioselectively controlled release of chiral drug (metoprolol) using chiral mesoporous silica materials

Energy Technology Data Exchange (ETDEWEB)

Guo Zhen; Liu Xianbin; Ng, Siu-Choon; Chen Yuan; Yang Yanhui [School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459 (Singapore); Du Yu, E-mail: du_yu@jlu.edu.cn, E-mail: yhyang@ntu.edu.sg [College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China)

2010-04-23

Chiral porous materials have attracted burgeoning attention on account of their potential applications in many areas, such as enantioseparation, chiral catalysis, chemical sensors and drug delivery. In this report, chiral mesoporous silica (CMS) materials with various pore sizes and structures were prepared using conventional achiral templates (other than chiral surfactant) and a chiral cobalt complex as co-template. The synthesized CMS materials were characterized by x-ray diffraction, nitrogen physisorption, scanning electron microscope and transmission electron microscope. These CMS materials, as carriers, were demonstrated to be able to control the enantioselective release of a representative chiral drug (metoprolol). The release kinetics, as modeled by the power law equation, suggested that the release profiles of metoprolol were remarkably dependent on the pore diameter and pore structure of CMS materials. More importantly, R- and S-enantiomers of metoprolol exhibited different release kinetics on CMS compared to the corresponding achiral mesoporous silica (ACMS), attributable to the existence of local chirality on the pore wall surface of CMS materials. The chirality of CMS materials on a molecular level was further substantiated by vibrational circular dichroism measurements.

Enantioselectively controlled release of chiral drug (metoprolol) using chiral mesoporous silica materials

International Nuclear Information System (INIS)

Guo Zhen; Liu Xianbin; Ng, Siu-Choon; Chen Yuan; Yang Yanhui; Du Yu

2010-01-01

Chiral porous materials have attracted burgeoning attention on account of their potential applications in many areas, such as enantioseparation, chiral catalysis, chemical sensors and drug delivery. In this report, chiral mesoporous silica (CMS) materials with various pore sizes and structures were prepared using conventional achiral templates (other than chiral surfactant) and a chiral cobalt complex as co-template. The synthesized CMS materials were characterized by x-ray diffraction, nitrogen physisorption, scanning electron microscope and transmission electron microscope. These CMS materials, as carriers, were demonstrated to be able to control the enantioselective release of a representative chiral drug (metoprolol). The release kinetics, as modeled by the power law equation, suggested that the release profiles of metoprolol were remarkably dependent on the pore diameter and pore structure of CMS materials. More importantly, R- and S-enantiomers of metoprolol exhibited different release kinetics on CMS compared to the corresponding achiral mesoporous silica (ACMS), attributable to the existence of local chirality on the pore wall surface of CMS materials. The chirality of CMS materials on a molecular level was further substantiated by vibrational circular dichroism measurements.

Contamination detector for inner surface of container

International Nuclear Information System (INIS)

Watanabe, Tadao.

1995-01-01

The present invention concerns a device for detecting contamination of radioactive materials on the inner surface of a vessel upon reutilizing the vessel for containing solidified radioactive wastes and transporting them. Namely, the detecting device has following functions. (1) A radiation detector detects the radioactive materials on the inner surface of the vessel. (2) A plurality of proximity switches measure the distance from the radiation detector to the wall surface of the vessel and are actuated if the distance is decreased to a predetermined value, (3) A vessel inner surface position calculation mechanism calculates the position of the inner surface of the vessel based on the information from a direction indicator and a height indicator. (4) A frontal limit detector detects the limit for allowing the radiation detector to proceed. (5) A vessel inner shape judging mechanism for judging the shape of the inner side of the vessel based on the signals from the proximity switches in a state where the frontal limit detector is operated and a vessel inner surface position signal outputted from the vessel inner surface position calculation mechanism. As a result, the shape of the inner side of the vessel can accurately be recognized, thereby improving accuracy of radiation measurement. (I.S.)

Training Materials for Release 3

DEFF Research Database (Denmark)

Wake, Jo Dugstad; Hansen, Cecilie; Debus, Kolja

This document, D7.4 – training materials for release 3, provides an overview of the training material for version 3 of the NEXT-TELL tools and methods. Previous documents submitted as part of work package 7, which is about teacher training, are D7.1 – Training Concept, D7.2 – Training Materials...... for Release 1 and D7.3 – Training Materials for Release 2. D7.4 builds on D7.1 and D7.2 and D7.3. D7.4 contains further development of previous work within WP7, essentially a revised theoretical approach to the teacher training, and expansion of the notion of tool training. The media in use have been expanded...

Contaminant interferences with SIMS analyses of microparticle impactor residues on LDEF surfaces

International Nuclear Information System (INIS)

Simon, C.G.; Batchelor, D.; Griffis, D.P.; Hunter, J.L.; Misra, V.; Ricks, D.A.; Wortman, J.J.

1992-01-01

Elemental analyses of impactor residues on high purity surface exposed to the low earth orbit (LEO) environment for 5.8 years on Long Duration Exposure Facility (LDEF) has revealed several probable sources for microparticles at this altitude, including natural micrometeorites and manmade debris ranging from paint pigments to bits of stainless steel. A myriad of contamination interferences were identified and their effects on impactor debris identification mitigated during the course of this study. These interferences included pre-, post-, and in-flight deposited particulate surface contaminants, as well as indigenous heterogeneous material contaminants. Non-flight contaminants traced to human origins, including spittle and skin oils, contributed significant levels of alkali-rich carbonaceous interferences. A ubiquitous layer of in-flight deposited silicaceous contamination varied in thickness with location on LDEF and proximity to active electrical fields. In-flight deposited (low velocity) contaminants included urine droplets and bits of metal film from eroded thermal blankets

Techniques for removing contaminated concrete surfaces

International Nuclear Information System (INIS)

Halter, J.M.; Sullivan, R.G.

1981-01-01

This discussion compares various techniques that have been used to clean concrete surfaces by removing the surface. Three techniques which have been investigated by the Pacific Northwest Laboratory for removing surfaces are also described: the water cannon, the concrete spaller, and high-pressure water jet. The equipment was developed with the assumption that removal of the top 1/8 to 1/4 in. of surface would remove most of the contamination. If the contamination has gone into cracks or deep voids in the surface, the removal processes can be repeated until the surface is acceptable

Contamination monitoring activities in Kanupp

Energy Technology Data Exchange (ETDEWEB)

Naqvi, S S [Karachi Nuclear Power Plant (Pakistan)

1997-06-01

The Karachi Nuclear Power Plant (Kanupp) is a 137 MWe pressurized heavy water reactor, designed and erected by the Canadian General Electric Company as a turn key project. The plant is in operation since it was commissioned in the year 1972. It is located at the Arabian Sea Coast about 15 miles to the west of Karachi. During its more than two decades of operation, the plant has generated about 8 billion units of electricity with an average life time availability factor of 60%. In Kanupp, radioactive contamination may exit due to the release of fission product, activation products etc., which may somehow escape from its confinement and may contaminate surface or other media such as air, water etc. In this paper, following items are described: main aspects of contamination, status of contamination monitoring, need of contamination monitoring, radiation protection activity, instruments, contamination, current status of contamination survey materials and their disposal, and environmental monitoring. (G.K.)

Development of guidance on applications of regulatory requirements for low specific activity materials and surface contaminated objects

International Nuclear Information System (INIS)

Pope, R.B.; Easton, E.P.; Shankman, S.F.

1997-01-01

In 1985, the International Atomic Energy Agency issued revised regulations for the safe transport of radioactive material. Significant among the changes were major revisions to requirements for Low Specific Activity (LSA) material and Surface Contaminated Objects (SCOs). In preparation for the adoption of these requirements into regulations in the United States, it became apparent that guidance on how to apply these requirements, clarifying technical uncertainties and ensuring proper implementation, would be needed both by the regulators and those regulated. Thus, the US Department of Transportation and the US Nuclear Regulatory Commission, with the assistance of staff from Oak Ridge National Laboratory, are preparing regulatory guidance for LSA material and SCO transport. The guidance will present examples of acceptable methods for demonstrating compliance with the revised rules. Ideas being investigated for inclusion in the pending guidance are discussed in this paper. Under current plans, the guidance will be issued for public comment prior to final issuance of the guidance in 1997

Development of guidance on applications of regulatory requirements for low specific activity materials and surface contaminated objects

International Nuclear Information System (INIS)

Pope, R.B.; Easton, E.P.; Shankman, S.F.; Boyle, R.W.

1997-01-01

In 1985, the International Atomic Energy Agency issued revised regulations for the safe transport of radioactive material. Significant among the changes were major revisions to requirements for Low Specific Activity (LSA) material and Surface Contaminated Objects (SCOs). In preparation for the adoption of these requirements into regulations in the United States, it became apparent that guidance on how to apply these requirements, clarifying technical uncertainties and ensuring proper implementation, would be needed both by the regulators and those regulated. Thus, the US Department of Transportation and the U.S. Nuclear Regulatory Commission, with the assistance of staff from Oak Ridge National Laboratory, are preparing regulatory guidance for LSA material and SCO transport. The guidance will present examples of acceptable methods for demonstrating compliance with the revised rules. Ideas being investigated for inclusion in the pending guidance are discussed in this paper. Under current plans, the guidance will be issued for public comment prior to final issue of the guidance in 1997. (Author)

Comparative Evaluation of Fluoride Releasing Ability of Various Restorative Materials after the Application of Surface Coating Agents – An In-vitro Study

Science.gov (United States)

Kishore, GVS; Sai-Sankar, AJ; Sridhar, M; Pranitha, Kakarla; Sai-Krishna, VS

2016-01-01

Introduction Fluoride plays a key role in prevention of dental caries and is also an essential element for oral health promotion both in children and adults. Aim The aim of the present study was to evaluate the effect of surface coating (petroleum jelly, G-Coat Plus) on the fluoride releasing property of conventional Glass Ionomer Cement (GIC) and Zirconomer. Materials and Methods A total of 30 disk shaped brass mold specimens (6±0.1mm in diameter and 2±0.1mm thickness) for each test group were fabricated with conventional GIC (Group A) and Zirconomer (Group B). These test groups were further divided into three subgroups of 10 each. The unprotected specimens act as control (Group A1 and B1), G-Coat Plus specimens as (Group A2 and B2) and for the remaining specimens petroleum jelly was applied (Group A3 and B3). Fluoride ion concentration was measured with a combination of fluoride ion specific electrode and ion analyzer for every 24 hours for 15 days. The data was statistically analyzed using Kruskal Wallis and Mann-Whitney U test. Results The Group B released significantly more fluoride than Group A. Among all the subgroups the greatest amount of fluoride was released from Group B1, in the first 24 hours followed by A1 and B2. The least was observed on 15th day with Group B3 and A3. Conclusion Both the tested materials (GIC and Zirconomer) used in the study exhibited fluoride release whether protected or unprotected with surface coating. Though there was a difference between the groups, the pattern of fluoride release was similar and continuous throughout the study period i.e., first the initial burst followed by sustained release. The results revealed Zirconomer released more fluoride and is comparable to conventional GIC. PMID:28209001

Description of measurement techniques for surface contaminations

International Nuclear Information System (INIS)

Bourrez, E.

2001-01-01

The needs of evaluation of the surface contamination are numerous in the processes of production and management of radioactive waste. The market of radiation protection materials proposes a lot of devices answering to the almost all these needs. These device have however their conditions and particular limits for use. To realize correct measurements it is use the device, the technique and the methods adapted to the need, by taking into account the optimization of economical aspect. (N.C.)

In-pile test of tritium release from tritium breeding materials (VOM-21H experiment)

International Nuclear Information System (INIS)

Kurasawa, Toshimasa; Takeshita, Hidefumi; Watanabe, Hitoshi; Yoshida, Hiroshi.

1986-10-01

Material development and blanket design of lithium-based ceramics such as lithium oxide, lithium aluminate, lithium silicate and lithium zirconate have been performed in Japan, United State of America and Europian Communities. Lithium oxide is a most attractive candidate for tritium breeding materials because of its high lithium density, high thermal conductivity and good tritium release performance. This work has been done to clarify the characteristics of tritium release and recovery from Li 2 O by means of in-situ tritium release measurement. The effects of temperature and sweep gas composition on the tritium release were investigated in this VOM-21H Experiment. Good measurement of tritium release was achieved but there were uncertainties in reproduciblity of data. The experimental results show that the role of surface adsorption/desorption makes a significant contribution to the tritium release and tritium inventory. Also, it is necessary to define the rate limiting process either diffusion or surface adsorption/desorption. (author)

Risk assessment of soil contamination criteria

International Nuclear Information System (INIS)

King, C.M.; Marter, W.L.; Montaque, D.F.; Holton, G.A.

1987-06-01

Criteria have been developed to select radioactive and nonradioactive contaminants at waste sites detailed analysis and risk assessment. These criteria were based on soil and water quality guidelines developed by various government agencies to determine if the criteria were appropriate. We performed a risk assessment of a hypothetical site which contained radioactive and nonradioactive contaminants at levels equal to the criteria values. Risks to the public from atmospheric, surface water, and groundwater exposure pathways were examined. Health risks to the public from atmospheric releases of radioactive and nonradioactive materials from a waste at soil criteria contamination levels are low. Health risks to the maximally exposed individual to chemical carcinogens are considerably below traditional EPA action levels. And health risks to the maximally exposed individual to atmospherically released radioactive contaminants is 1.88 x 10 -7 , more than a factor of 5 less than 10 -6 . Based on our atmospheric exposure pathways analysis and risk assessment, the applied soil criteria are appropriate for screening out unimportant risk contributors to human health from atmospheric exposure pathways. 13 refs., 3 figs., 7 tabs

Approach and issues toward development of risk-based release standards for radioactive scrap metal recycle and reuse

International Nuclear Information System (INIS)

Chen, S.Y.; Nieves, L.A.; Nabelssi, B.K.; LePoire, D.J.

1994-01-01

The decontamination and decommissioning of nuclear facilities is expected to generate large amounts of slightly radioactive scrap metal (RSM). It is likely that some of these materials will be suitable for recycling and reuse. The amount of scrap steel from DOE facilities, for instance, is estimated to be more than one million tons (Hertzler 1993). However, under current practice and without the establishment of acceptable recycling standards, the RSM would be disposed of primarily as radioactive low-level waste (LLW). In the United States, no specific standards have been developed for the unrestricted release of bulk contaminated materials. Although standards for unrestricted release of radioactive surface contamination (NRC 1974) have existed for about 20 years, the release of materials is not commonly practiced because of the lack of risk-based justifications. Recent guidance from international bodies (IAEA 1988) has established a basis for deriving risk-based release limits for radioactive materials. It is important, therefore, to evaluate the feasibility of recycling and associated issues necessary for the establishment of risk-based release limits for the radioactive metals

Effective decolorization and adsorption of contaminant from industrial dye effluents using spherical surfaced magnetic (Fe{sub 3}O{sub 4}) nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Suriyaprabha, R., E-mail: sooriyarajendran@gmail.com; Khan, Samreen Heena [Centre for Nanosciences, Central University of Gujarat, Gandhainagar-382030 (India); Pathak, Bhawana; Fulekar, M. H., E-mail: mhfulekar@yahoo.com [School of Environment and Sustainable Development, Central University of Gujarat, Gandhainagar-382030 (India)

2016-04-13

Treatment of highly concentrated Industrial dye stuff effluents released in the environment is the major issue faced in the era of waste management as well as in water pollution. Though there is availability of conventional techniques in large numbers, there is a need of efficient and effective advance technologies. In account of that, Nanotechnology plays a prominent role to treat the heavy metals, organic and inorganic contaminants using smart materials in nano regime (1 -100 nm). Among these nanomaterials like Iron Oxide (Fe{sub 3}O{sub 4}, magnetic nanoparticle) is one of the most promising candidates to remove the heavy metals from the industrial effluent. Fe{sub 3}O{sub 4} is the widely used smart material with magnetic property having high surface area; high surface to volume ratio provides more surface for the chemical reaction for the surface adsorption. Fe{sub 3}O{sub 4} nanoparticles have been synthesized using sonochemical method using ultra frequency in aqueous solution under optimized conditions. The as-synthesized nanoparticle was analyzed using different characterization tool. The Transmission Electron microscope (TEM) images revealed 10-12 nm spherical shape nanoparticles; crystal phase and surface morphology was confirmed by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM), respectively. The functional group were identified by Fourier Transform-Infra Red Spectroscopy (FT-IR), revealed the bending and stretching vibrations associated with Iron Oxide nanoparticle. In present study, for the efficient removal of contaminants, different concentration (10-50 ppm) of dye stuff effluent has been prepared and subjected to adsorption and decolourization at definite time intervals with Fe{sub 3}O{sub 4} nanoparticles. The concentration of Iron oxide and the time (45 mins) was kept fixed for the reaction whereas the concentration of dye stuff effluent was kept varying. It was found that the spherical shaped Fe{sub 3}O{sub 4} proved to be

Modeling for Airborne Contamination

International Nuclear Information System (INIS)

F.R. Faillace; Y. Yuan

2000-01-01

The objective of Modeling for Airborne Contamination (referred to from now on as ''this report'') is to provide a documented methodology, along with supporting information, for estimating the release, transport, and assessment of dose to workers from airborne radioactive contaminants within the Monitored Geologic Repository (MGR) subsurface during the pre-closure period. Specifically, this report provides engineers and scientists with methodologies for estimating how concentrations of contaminants might be distributed in the air and on the drift surfaces if released from waste packages inside the repository. This report also provides dose conversion factors for inhalation, air submersion, and ground exposure pathways used to derive doses to potentially exposed subsurface workers. The scope of this report is limited to radiological contaminants (particulate, volatile and gaseous) resulting from waste package leaks (if any) and surface contamination and their transport processes. Neutron activation of air, dust in the air and the rock walls of the drift during the preclosure time is not considered within the scope of this report. Any neutrons causing such activation are not themselves considered to be ''contaminants'' released from the waste package. This report: (1) Documents mathematical models and model parameters for evaluating airborne contaminant transport within the MGR subsurface; and (2) Provides tables of dose conversion factors for inhalation, air submersion, and ground exposure pathways for important radionuclides. The dose conversion factors for air submersion and ground exposure pathways are further limited to drift diameters of 7.62 m and 5.5 m, corresponding to the main and emplacement drifts, respectively. If the final repository design significantly deviates from these drift dimensions, the results in this report may require revision. The dose conversion factors are further derived by using concrete of sufficient thickness to simulate the drift

Characterizing, for packaging and transport, large objects contaminated by radioactive material having a limited A2 value

International Nuclear Information System (INIS)

Pope, R.B.; Shappert, L.B.; Michelhaugh, R.D.; Cash, J.M.; Best, R.E.

1998-02-01

The International Atomic Energy Agency (IAEA) Regulations for the safe packaging and transportation of radioactive materials follow a graded approach to the requirements for both packaging and controls during transport. The concept is that, the lower the risk posed to the people and the environment by the contents, (1) the less demanding are the packaging requirements and (2) the smaller in number are the controls imposed on the transport of the material. There are likely to be a great number of situations arising in coming years when large objects, contaminated with radioactive material having unlimited A 2 values will result from various decommissioning and decontamination (D and D) activities and will then require shipment from the D and D site to a disposal site. Such situations may arise relatively frequently during the cleanup of operations involving mining, milling, feedstock, and uranium enrichment processing facilities. Because these objects are contaminated with materials having an unlimited A 2 value they present a low radiological risk to worker and public safety and to the environment during transport. However, when these radioactive materials reside on the surfaces of equipment and other large objects, where the equipment and objects themselves are not radioactive, the radioactive materials appear as surface contamination and, if the contaminated object is categorized as a surface contaminated object, it would need to be packaged for shipment according to the requirements of the Regulations for SCO. Despite this categorization, alternatives may be available which will allow these contaminants, when considered by themselves for packaging and transport, to be categorized as either (1) a limited quantity of radioactive material to be shipped in an excepted package or (2) low specific activity (LSA) materials to be shipped in an IP-1 package or possibly even shipped unpackaged. These options are discussed in this paper

49 CFR 175.705 - Radioactive contamination.

Science.gov (United States)

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Radioactive contamination. 175.705 Section 175.705... Regulations Applicable According to Classification of Material § 175.705 Radioactive contamination. (a) A... (radioactive) materials that may have been released from their packagings. (b) When contamination is present or...

Resolving Radiological Classification and Release Issues for Many DOE Solid Wastes and Salvageable Materials

International Nuclear Information System (INIS)

Hochel, R.C.

1999-01-01

The cost effective radiological classification and disposal of solid materials with potential volume contamination, in accordance with applicable U.S. Department of Energy (DOE) Orders, suffers from an inability to unambiguously distinguish among transuranic waste, low-level waste, and unconditional-release materials. Depending on the classification, disposal costs can vary by a hundred-fold. But in many cases, the issues can be easily resolved by a combination of process information, some simple measurements, and calculational predictions from a computer model for radiation shielding.The proper classification and disposal of many solid wastes requires a measurement regime that is able to show compliance with a variety of institutional and regulatory contamination limits. Although this is not possible for all solid wastes, there are many that do lend themselves to such measures. Several examples are discussed which demonstrate the possibilities, including one which was successfully applied to bulk contamination.The only barriers to such broader uses are the slow-to-change institutional perceptions and procedures. For many issues and materials, the measurement tools are available; they need only be applied

Resolving Radiological Classification and Release Issues for Many DOE Solid Wastes and Salvageable Materials

Energy Technology Data Exchange (ETDEWEB)

Hochel, R.C.

1999-06-14

The cost effective radiological classification and disposal of solid materials with potential volume contamination, in accordance with applicable U.S. Department of Energy (DOE) Orders, suffers from an inability to unambiguously distinguish among transuranic waste, low-level waste, and unconditional-release materials. Depending on the classification, disposal costs can vary by a hundred-fold. But in many cases, the issues can be easily resolved by a combination of process information, some simple measurements, and calculational predictions from a computer model for radiation shielding.The proper classification and disposal of many solid wastes requires a measurement regime that is able to show compliance with a variety of institutional and regulatory contamination limits. Although this is not possible for all solid wastes, there are many that do lend themselves to such measures. Several examples are discussed which demonstrate the possibilities, including one which was successfully applied to bulk contamination.The only barriers to such broader uses are the slow-to-change institutional perceptions and procedures. For many issues and materials, the measurement tools are available; they need only be applied.

Surface PEGylation of mesoporous silica materials via surface-initiated chain transfer free radical polymerization: Characterization and controlled drug release.

Science.gov (United States)

Huang, Long; Liu, Meiying; Mao, Liucheng; Huang, Qiang; Huang, Hongye; Wan, Qing; Tian, Jianwen; Wen, Yuanqing; Zhang, Xiaoyong; Wei, Yen

2017-12-01

As a new type of mesoporous silica materials with large pore diameter (pore size between 2 and 50nm) and high specific surface areas, SBA-15 has been widely explored for different applications especially in the biomedical fields. The surface modification of SBA-15 with functional polymers has demonstrated to be an effective way for improving its properties and performance. In this work, we reported the preparation of PEGylated SBA-15 polymer composites through surface-initiated chain transfer free radical polymerization for the first time. The thiol group was first introduced on SBA-15 via co-condensation with γ-mercaptopropyltrimethoxysilane (MPTS), that were utilized to initiate the chain transfer free radical polymerization using poly(ethylene glycol) methyl ether methacrylate (PEGMA) and itaconic acid (IA) as the monomers. The successful modification of SBA-15 with poly(PEGMA-co-IA) copolymers was evidenced by a series of characterization techniques, including 1 H NMR, FT-IR, TGA and XPS. The final SBA-15-SH- poly(PEGMA-co-IA) composites display well water dispersity and high loading capability towards cisplatin (CDDP) owing to the introduction of hydrophilic PEGMA and carboxyl groups. Furthermore, the CDDP could be released from SBA-15-SH-poly(PEGMA-co-IA)-CDDP complexes in a pH dependent behavior, suggesting the potential controlled drug delivery of SBA-15-SH-poly(PEGMA-co-IA). More importantly, the strategy should be also useful for fabrication of many other functional materials for biomedical applications owing to the advantages of SBA-15 and well monomer adoptability of chain transfer free radical polymerization. Copyright © 2017 Elsevier B.V. All rights reserved.

Subsurface Contamination Control

Energy Technology Data Exchange (ETDEWEB)

Y. Yuan

2001-12-12

There are two objectives of this report, ''Subsurface Contamination Control''. The first is to provide a technical basis for recommending limiting radioactive contamination levels (LRCL) on the external surfaces of waste packages (WP) for acceptance into the subsurface repository. The second is to provide an evaluation of the magnitude of potential releases from a defective WP and the detectability of the released contents. The technical basis for deriving LRCL has been established in ''Retrieval Equipment and Strategy for Wp on Pallet'' (CRWMS M and O 2000g, 6.3.1). This report updates the derivation by incorporating the latest design information of the subsurface repository for site recommendation. The derived LRCL on the external surface of WPs, therefore, supercede that described in CRWMS M and O 2000g. The derived LRCL represent the average concentrations of contamination on the external surfaces of each WP that must not be exceeded before the WP is to be transported to the subsurface facility for emplacement. The evaluation of potential releases is necessary to control the potential contamination of the subsurface repository and to detect prematurely failed WPs. The detection of failed WPs is required in order to provide reasonable assurance that the integrity of each WP is intact prior to MGR closure. An emplaced WP may become breached due to manufacturing defects or improper weld combined with failure to detect the defect, by corrosion, or by mechanical penetration due to accidents or rockfall conditions. The breached WP may release its gaseous and volatile radionuclide content to the subsurface environment and result in contaminating the subsurface facility. The scope of this analysis is limited to radioactive contaminants resulting from breached WPs during the preclosure period of the subsurface repository. This report: (1) documents a method for deriving LRCL on the external surfaces of WP for acceptance into the

Surface contamination effects on leaf chemical composition in the Atlantic Forest

International Nuclear Information System (INIS)

Ferrari, A.A.; Franca, E.J.; Fernandes, E.A.N.; Bacchi, M.A.

2006-01-01

The exogenous material that adheres to the leaf surface affects the elemental composition of the plant itself, thereby constituting one of the major error sources in plant analysis. The present work investigated the surface contamination of leaves from the Atlantic Forest. Instrumental neutron activation analysis (INAA) was applied to assess the efficiency of leaf EDTA-washing. Chemical element concentrations were corrected using Sc (soil tracer) since resuspended soil is the main source of contamination in leaves. As a result, EDTA-washing should be used mainly for the evaluation of terrigenous elements, while the Sc-corrected concentrations are considered satisfactory for the other elements. (author)

Evaluation of indigenously developed plastic scintillator sheet detector for surface radioactive contamination monitoring application

International Nuclear Information System (INIS)

Sahani, R.M.; Chaudhary, H.S.; Mahala, V.K.; Senwar, K.R.; Meena, J.P.

2018-01-01

Radioactive contamination may be caused by release of radioactivity in the environment due to accident at nuclear plant/reactor or spillage of loose radioactive materials in a laboratory. The protection of workers from potentially hazardous radiations emitted by the contaminants is a matter of prime concern. The detection of such radiations requires a monitoring system capable of measuring the level of radioactivity at the contaminated site. Plastic scintillators are widely used for large area radiation monitoring due to the ease of preparation in different shape and sizes. These detectors are sensitive to beta and gamma radiation therefore can be used for monitoring of beta and gamma contamination. In this paper, performance results of indigenously developed plastic scintillator sheet of area 800 cm 2 are reported

Effect of surface water on tritium release behavior from Li4SiO4

International Nuclear Information System (INIS)

Hanada, T.; Fukada, S.; Nishikawa, M.; Suematsu, K.; Yamashita, N.; Kanazawa, T.

2010-01-01

The tritium release model to represent the release behavior of bred tritium from solid breeder materials has been developed by the blanket group of Kyushu University. It has been found that water is released to the purge gas from solid breeder materials and that this water affects the tritium release behavior. In this study, the amount of surface water released from Li 4 SiO 4 is quantified by the experiment. In addition, the tritium release behavior from Li 4 SiO 4 are estimated based on the tritium release model using parameters obtained in our studies under conditions of commercial reactor operation and ITER test blanket module operation. The effect of the surface water on tritium release behavior is discussed from the obtained results. Moreover, the tritium inventory of Li 4 SiO 4 is discussed based on calculation under the unsteady state condition. Further, the effects of grain size and temperature on distribution of tritium inventory under the steady state condition are evaluated, and the optimal grain size is discussed from the view point of tritium release from Li 4 SiO 4 .

Kinetics of radiocesium released from contaminated soil by fertilizer solutions

International Nuclear Information System (INIS)

Chiang, P.N.; Wang, M.K.; Huang, P.M.; Wang, J.J.

2008-01-01

137 Cs is one of the major artificial radionuclides found in environments; but the mechanisms behind fertilizer-induced 137 Cs desorption from soil remain unknown. This study aimed to investigate the kinetics and mechanisms underlying the various cations and anions that cause Cs release from soil under acidic conditions. NH 4 H 2 PO 4 (1 M), 0.5 M (NH 4 ) 2 SO 4 , 1 M NH 4 Cl, 1 M KCl or 1 M NaCl solutions were added to 137 Cs-contaminated soil. The power function model well described the short term 137 Cs desorption with the solutions. The rate coefficients for 137 Cs release from soil in NH 4 H 2 PO 4 , (NH 4 ) 2 SO 4 , NH 4 Cl, and KCl solutions were 7.7, 7.3, 6.8, and 6.1 times higher than the rate observed in a NaCl solution, respectively. The NH 4 H 2 PO 4 and (NH 4 ) 2 SO 4 solutions induced significantly greater 137 Cs release from the contaminated soil than the NH 4 Cl, KCl and NaCl solutions. After four times repeated extractions with the fertilizer solutions, the total amount of 137 Cs extracted by (NH 4 ) 2 SO 4 and NH 4 Cl solutions reached equilibrium, while that extracted using an NH 4 H 2 PO 4 solution continued to increase. The combined effect of phosphate and protons was the major mechanism behind 137 Cs release from contaminated soils, when an NH 4 H 2 PO 4 solution was used

Experimental analysis on removal factor of smear method in measurement of surface contamination

International Nuclear Information System (INIS)

Sugiura, Nobuyuki; Taira, Junichi; Takenaka, Keisuke; Yamanaka, Kazuo; Sugai, Kenji; Kosako, Toshiso

2007-01-01

The smear test is one of the important ways to measure surface contamination. The loose contamination under the high background radiation, which is more significant in handling non-sealed radioisotopes, can be evaluated by this method. The removal factor is defined as the ratio of the activity removed from the surface by one smear to the whole activity of the removable surface contamination. The removal factor is greatly changed by the quality and condition of surface materials. In this study, the values of removal factor at several typical surface conditions were evaluated experimentally and the practical application of those values was considered. It is required the smear should be pressed by moderate pressure when wiping the surface. The pressure from 1.0 kg to 1.5 kg per filter paper was recommended. The removal factor showed lower value in wiping by the pressure below 1.0 kg. The value of 0.5 for the removal factor could be applied to the smooth surface of linoleum, concrete coated with paint or epoxy resin, stainless steel and glass with the statistical allowance. (author)

Influence of surface chemistry of carbon materials on their interactions with inorganic nitrogen contaminants in soil and water.

Science.gov (United States)

Sumaraj; Padhye, Lokesh P

2017-10-01

Inorganic nitrogen contaminants (INC) (NH 4 + , NO 3 - , NO 2 - , NH 3 , NO, NO 2 , and N 2 O) pose a growing risk to the environment, and their remediation methods are highly sought after. Application of carbon materials (CM), such as biochar and activated carbon, to remediate INC from agricultural fields and wastewater treatment plants has gained a significant interest since past few years. Understanding the role of surface chemistry of CM in adsorption of various INC is highly critical to increase adsorption efficiency as well as to assess the long term impact of using these highly recalcitrant CM for remediation of INC. Critical reviews of adsorption studies related to INC have revealed that carbon surface chemistry (surface functional groups, pH, Eh, elemental composition, and mineral content) has significant influence on adsorption of INC. Compared to basic functional groups, oxygen containing surface functional groups have been found to be more influential for adsorption of INC. However, basic sites on carbon materials still play an important role in chemisorption of anionic INC. Apart from surface functional groups, pH, Eh and pH zpc of CM and elemental and mineral composition of its surface are important properties capable of altering INC interactions with CM. This review summarizes our current understanding of INC interactions with CM's surface through the known chemisorption mechanisms: electrostatic interaction, hydrogen bonding, electron donor-acceptor mechanism, hydrophobic and hydrophilic interaction, chemisorption aided by minerals, and interactions influenced by pH and elemental composition. Change in surface chemistry of CM in soil during aging is also discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

A model to determine the radiological implications of non-fixed radioactive contamination on the surfaces of packages and conveyances

International Nuclear Information System (INIS)

Hughes, J.S.; Warner Jones, S.M.; Lizot, M.T.; Perrin, M.L.; Thierfeld, S.; Schroedl, E.; Schwarz, G.; Rawl, R.; Munakata, M.; Hirose, M.

2004-01-01

The surfaces of packages and conveyances used to transport radioactive materials can sometimes become contaminated with radioactive material. This usually occurs as a result of the transfer of radioactive material from areas in which these packages and conveyances are handled. This contamination may subsequently be transferred to transport equipment, workers and to areas accessible to the public. This can represent a significant radiation safety issue that requires careful management. The current regulatory limits for non-fixed contamination on packages and conveyances have been in use for over 40 years, and are based on a simple exposure model. However, the bases on which these limits were derived have been subject to changes, as a result of successive revisions of international recommendations. In recognition of this need for a review and analysis of the current contamination limits an IAEA Co-ordinated Research Project (CRP) on the ''Radiological Aspects of Package and Conveyance Non-Fixed Contamination'' was initiated to review the scientific basis for the current regulatory limits for surface contamination. The CRP was also to develop guidance material for evaluating the radiological significance of surface contamination to workers and the public in light of state-of-the-art research, technical developments and current transport practices. The specific objectives of the work undertaken within this multi-national CRP were, in accordance with the terms of reference: To ensure that appropriate models exist for all package types including consideration of the aspects pertinent for assessing and revising a surface contamination model for transport. To collect - where possible - contamination, operational and dosimetric data to ensure modelling consistency. To use models for assessing the limitations and optimisation of radiation doses incurred in transport operations, and to consider preventive methods for package and conveyance contamination

MERCURY CONTAMINATED MATERIAL DECONTAMINATION METHODS: INVESTIGATION AND ASSESSMENT

Energy Technology Data Exchange (ETDEWEB)

M.A. Ebadian, Ph.D.

2001-01-01

Over the years mercury has been recognized as having serious impacts on human health and the environment. This recognition has led to numerous studies that deal with the properties of various mercury forms, the development of methods to quantify and speciate the forms, fate and transport, toxicology studies, and the development of site remediation and decontamination technologies. This report reviews several critical areas that will be used in developing technologies for cleaning mercury from mercury-contaminated surfaces of metals and porous materials found in many DOE facilities. The technologies used for decontamination of water and mixed wastes (solid) are specifically discussed. Many technologies that have recently appeared in the literature are included in the report. Current surface decontamination processes have been reviewed, and the limitations of these technologies for mercury decontamination are discussed. Based on the currently available technologies and the processes published recently in the literature, several processes, including strippable coatings, chemical cleaning with iodine/iodide lixiviant, chemisorbing surface wipes with forager sponge and grafted cotton, and surface/pore fixation through amalgamation or stabilization, have been identified as potential techniques for decontamination of mercury-contaminated metal and porous surfaces. Their potential merits and applicability are discussed. Finally, two processes, strippable coatings and chemical cleaning with iodine/iodide lixiviant, were experimentally investigated in Phase II of this project.

Underground processing method for radiation-contaminated material and transferring method for buffer molding material

International Nuclear Information System (INIS)

Akasaka, Hidenari; Shimura, Satoshi; Asano, Eiichi; Yamagata, Junji; Ninomiya, Nobuo; Kawakami, Susumu.

1995-01-01

A bottomed molding material (buffer molding material) is formed into a bottomed cylindrical shape by solidifying, under pressure, powders such as of bentonite into a highly dense state by a cold isotropic pressing or the like, having a hole for accepting and containing a vessel for radiation-contaminated materials. The bottomed cylindrical molding material is loaded on a transferring vessel, and transferred to a position near the site for underground disposal. The bottomed cylindrical molding material having a upwarded containing hole is buried in the cave for disposal. The container for radiation-contaminated material is loaded and contained in the containing hole of the bottomed cylindrical molding material. A next container for radiation-contaminated materials is juxtaposed thereover. Then, a bottomed cylindrical molding material having a downwarded containing hole is covered to the container for the radiation-contaminated material in a state being protruded upwardly. The radiation-contaminated material is thus closed by a buffer material of the same material at the circumference thereof. (I.N.)

Scaling of the movement and fate of contaminant releases in the vadose zone by centrifuge modelling; Reproduction de la migration et de l'evolution de polluants rejetes dans la zone insaturee par centrifugation

Energy Technology Data Exchange (ETDEWEB)

Knight, M.A. [Waterloo Univ., ON (Canada). Dept. of Civil Engineering; Cooke, A.B. [New Brunswick Univ., Dept. of Civil Engineering, Fredericton, NB (Canada); Mitchell, R.J. [Queen' s Univ., Dept. of Civil Engineering, Kingston, ON (Canada)

2000-07-01

The release of contaminants into partially water-wet porous media is a complex problem to simulate in the laboratory and numerically. Research into the application of a geo-environmental centrifuge to simulate non-reactive contaminant releases in partially water-wet sand was performed at Queen's University in Kingston, Ontario. This paper highlights results of the Queen's University centrifuge contaminant release studies from 1990 to present. Results of this study support the conclusion that a geo-environmental centrifuge can be used to replicate the complex behaviour of non-reactive contaminant releases into water-wet sand provided that attention is paid to the modelling materials and modelling scales. (authors)

Bonding of radioactive contamination. IV. Effect of surface finish

International Nuclear Information System (INIS)

Rankin, W.N.

1983-01-01

The mechanisms by which radioactive contamination would be bonded to a DWPF canister are being investigated. Previous investigations in this series have examined the effects of temperature, oxidation before contamination, and atmosphere composition control on the bonding of contamination. This memorandum describes the results of tests to determine the effect of special surface finishes on the bonding of contamination to waste glass canisters. Surface pretreatments which produce smoother canister surfaces actually cause radioactive contamination to be more tightly bonded to the metal surface than on an untreated surface. Based on the results of these tests it is recommended that the canister surface finish be specified as having a bright cold rolled mill finish equivalent to ASTM No. 2B. 7 references, 3 figures, 3 tables

Innovative technology for expedited site remediation of extensive surface and subsurface contamination

International Nuclear Information System (INIS)

Audibert, J.M.E.; Lew, L.R.

1994-01-01

Large scale surface and subsurface contamination resulted from numerous releases of feed stock, process streams, waste streams, and final product at a major chemical plant. Soil and groundwater was contaminated by numerous compounds including lead, tetraethyl lead, ethylene dibromide, ethylene dichloride, and toluene. The state administrative order dictated that the site be investigated fully, that remedial alternative be evaluated, and that the site be remediated within a year period. Because of the acute toxicity and extreme volatility of tetraethyl lead and other organic compounds present at the site and the short time frame ordered by the regulators, innovative approaches were needed to carry out the remediation while protecting plant workers, remediation workers, and the public

The total amounts of radioactively contaminated materials in forests in Fukushima, Japan

Science.gov (United States)

Hashimoto, Shoji; Ugawa, Shin; Nanko, Kazuki; Shichi, Koji

2012-01-01

There has been leakage of radioactive materials from the Fukushima Daiichi Nuclear Power Plant. A heavily contaminated area (≥ 134, 137Cs 1000 kBq m−2) has been identified in the area northwest of the plant. The majority of the land in the contaminated area is forest. Here we report the amounts of biomass, litter (small organic matter on the surface of the soil), coarse woody litter, and soil in the contaminated forest area. The estimated overall volume and weight were 33 Mm3 (branches, leaves, litter, and coarse woody litter are not included) and 21 Tg (dry matter), respectively. Our results suggest that removing litter is an efficient method of decontamination. However, litter is being continuously decomposed, and contaminated leaves will continue to fall on the soil surface for several years; hence, the litter should be removed promptly but continuously before more radioactive elements are transferred into the soil. PMID:22639724

Plutonium contaminated materials research programme

International Nuclear Information System (INIS)

Higson, S.G.

1986-01-01

The paper is a progress report for 1985 from the Plutonium Contaminated Materials Working Party (PCMWP). The PCMWP co-ordinates research and development on a national basis in the areas of management, treatment and immobilisation of plutonium contaminated materials, for the purpose of waste management. The progress report contains a review of the development work carried out in eight areas, including: reduction of arisings, plutonium measurement, sorting and packaging, washing of shredded combustible PCM, decommissioning and non-combustible PCM treatment, PCM immobilisation, treatment of alpha bearing liquid wastes, and engineering objectives. (UK)

Visible-light system for detecting doxorubicin contamination on skin and surfaces.

Science.gov (United States)

Van Raalte, J; Rice, C; Moss, C E

1990-05-01

A portable system that uses fluorescence stimulated by visible light to identify doxorubicin contamination on skin and surfaces was studied. When activated by violet-blue light in the 465-nm range, doxorubicin fluoresces, emitting orange-red light in the 580-nm range. The light source to stimulate fluorescence was a slide projector with a filter to selectively pass short-wave (blue) visible light. Fluorescence was both observed visually with viewing spectacles and photographed. Solutions of doxorubicin in sterile 0.9% sodium chloride injection were prepared in nine standard concentrations ranging from 2 to 0.001 mg/mL. Droplets of each admixture were placed on stainless steel, laboratory coat cloth, pieces of latex examination glove, bench-top absorbent padding, and other materials on which antineoplastics might spill or leak. These materials then were stored for up to eight weeks and photographed weekly. The relative ability of water, household bleach, hydrogen peroxide solution, and soap solution to deactivate doxorubicin was also measured. Finally, this system was used to inspect the antineoplastic-drug preparation and administration areas of three outpatient cancer clinics for doxorubicin contamination. Doxorubicin fluorescence was easily detectable with viewing spectacles when a slide projector was used as the light source. The photographic method was sensitive for doxorubicin concentrations from 2.0 to 0.001 mg/mL. Immersion of study materials in bleach for one minute eliminated detectable fluorescence. Doxorubicin contamination is detectable for at least eight weeks in the ambient environment. Probable doxorubicin contamination was detected in two of the three clinics surveyed. A safe, portable system that uses fluorescence stimulated by visible light is a sensitive method for detecting doxorubicin on skin and surfaces.

Surface water management at a mixed waste remediation site

International Nuclear Information System (INIS)

Schlotzhauer, D.S.; Warbritton, K.R.

1991-01-01

The Weldon Spring Remedial Action Project (WSSRAP) deals with chemical and radiological contaminants. MK-Ferguson Company is managing the project under contract with the US Department of Energy. Remedial activities include demolishing buildings, constructing material storage and staging areas, excavating and consolidating waste materials, and treating and disposing of the materials in a land disposal facility. Due to the excavation and construction required during remediation, a well-planned surface water management system is essential. Planning involves characterization of source areas and surface water transport mechanisms and identification of applicable regulations. System components include: erosion control sediment control, flow attenuation, and management of contaminated water. Combinations of these components may be utilized during actual construction and remediation to obtain optimum control. Monitoring is performed during implementation in order to assess the effectiveness of control measures. This management scheme provides for comprehensive management of surface water at this site by providing control and/or treatment to appropriate standards. Although some treatment methodologies for contaminated water are specific to site contaminants, this comprehensive program provides a management approach which is applicable to many remedial projects in order to minimize contaminant release and meet Clean Water Act requirements

Degassing, gas retention and release in Fe(0) permeable reactive barriers.

Science.gov (United States)

Ruhl, Aki S; Jekel, Martin

2014-04-01

Corrosion of Fe(0) has been successfully utilized for the reductive treatment of multiple contaminants. Under anaerobic conditions, concurrent corrosion leads to the generation of hydrogen and its liberation as a gas. Gas bubbles are mobile or trapped within the irregular pore structure leading to a reduction of the water filled pore volume and thus decreased residence time and permeability (gas clogging). With regard to the contaminant transport to the reactive site, the estimation of surface properties of the reactive material indicated that individual gas bubbles only occupied minor contact areas of the reactive surface. Quantification of gas entrapment by both gravimetrical and tracer investigations revealed that development of preferential flow paths was not significant. A novel continuous gravimetrical method was implemented to record variations in gas entrapment and gas bubble releases from the reactive filling. Variation of grain size fractions revealed that the pore geometry had a significant impact on gas release. Large pores led to the release of comparably large gas amounts while smaller volumes were released from finer pores with a higher frequency. Relevant processes are explained with a simplified pictorial sequence that incorporates relevant mechanisms. Copyright © 2014 Elsevier B.V. All rights reserved.

Material Cycles and Chemicals: Dynamic Material Flow Analysis of Contaminants in Paper Recycling

DEFF Research Database (Denmark)

Pivnenko, Kostyantyn; Laner, David; Astrup, Thomas Fruergaard

2016-01-01

material source-segregation and collection was the least effective strategy for reducing chemical contamination, if the overall recycling rates should be maintained at the current level (approximately 70% for Europe). The study provides a consistent approach for evaluating contaminant levels in material......This study provides a systematic approach for assessment of contaminants in materials for recycling. Paper recycling is used as an illustrative example. Three selected chemicals, bisphenol A (BPA), diethylhexyl phthalate (DEHP) and mineral oil hydrocarbons (MOHs), are evaluated within the paper...... cycle. The approach combines static material flow analysis (MFA) with dynamic material and substance flow modeling. The results indicate that phasing out of chemicals is the most effective measure for reducing chemical contamination. However, this scenario was also associated with a considerable lag...

Issues in recycling and disposal of radioactively contaminated materials

International Nuclear Information System (INIS)

Kluk, A.F.; Hocking, E.K.; Roberts, R.; Phillips, J.W.

1993-01-01

The Department of Energy's present stock of potentially re-usable and minimally radioactively contaminated materials will increase significantly as the Department's remediation activities expand. As part of its effort to minimize wastes, the Department is pursuing several approaches to recover valuable materials such as nickel, copper, and steel, and reduce the high disposal costs associated with contaminated materials. Key approaches are recycling radioactively contaminated materials or disposing of them as non-radioactive waste. These approaches are impeded by a combination of potentially conflicting Federal regulations, State actions, and Departmental policies. Actions to promote or implement these approaches at the Federal, State, or Departmental level involve issues which must be addressed and resolved. The paramount issue is the legal status of radioactively contaminated materials and the roles of the Federal and State governments in regulating those materials. Public involvement is crucial in the debate surrounding the fate of radioactively contaminated materials

A review of biochars' potential role in the remediation, revegetation and restoration of contaminated soils

International Nuclear Information System (INIS)

Beesley, Luke; Moreno-Jimenez, Eduardo; Gomez-Eyles, Jose L.; Harris, Eva; Robinson, Brett; Sizmur, Tom

2011-01-01

Biochars are biological residues combusted under low oxygen conditions, resulting in a porous, low density carbon rich material. Their large surface areas and cation exchange capacities, determined to a large extent by source materials and pyrolysis temperatures, enables enhanced sorption of both organic and inorganic contaminants to their surfaces, reducing pollutant mobility when amending contaminated soils. Liming effects or release of carbon into soil solution may increase arsenic mobility, whilst low capital but enhanced retention of plant nutrients can restrict revegetation on degraded soils amended only with biochars; the combination of composts, manures and other amendments with biochars could be their most effective deployment to soils requiring stabilisation by revegetation. Specific mechanisms of contaminant-biochar retention and release over time and the environmental impact of biochar amendments on soil organisms remain somewhat unclear but must be investigated to ensure that the management of environmental pollution coincides with ecological sustainability. - Highlights: → Biochars can reduce mobilities of some organic and inorganic pollutants in soil. → Source material and production conditions influence pollutant retention. → Highly alkaline pH and water soluble carbon can undesirably mobilise some elements. → Large surface area may be toxic to soil fauna but create microbial niches. → Efficacy of biochar may depend on other organic materials applied in combination. - Biochars can reduce the mobility and impact of some soil pollutants but, if applied alone, may fail to support soil restoration, revegetation and hence ecologically circumspect remediation.

Engineering evaluation/cost analysis for the proposed removal of contaminated materials at the Elza Gate site, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

1991-06-01

This engineering evaluation/cost analysis (EE/CA) has been prepared in support of the proposed removal action for cleanup of radioactive and chemically contaminated soil at the Elza Gate site in Oak Ridge, Tennessee. This property became contaminated as a result of storage of ore residues, equipment, and other materials for the US Atomic Energy Commission. The US Department of Energy is responsible for cleanup of portions of the site under its Formerly Utilized Sites Remedial Action Program. In December 1990 an area known as Pad 1 was abrasively scoured to remove surface contamination, and in March 1991 removal of Pad 1 contamination was begun under a separate EE/CA. This EE/CA is intended to cover the remaining portions of the site for which the Department of Energy has responsibility. It has been determined that an EE/CA report is appropriate documentation for the proposed removal action. This EE/CA covers removal of contaminated soils and contaminated concrete rubble from the Elza Gate site. The primary objectives of this EE/CA report are to identify and describe the preferred removal action, and to document the selection of response activities that will mitigate the potential for release of contaminants from the property into the environment and that will minimize the associated threats to human health or welfare and the environment. The preferred alternative is disposition on the Oak Ridge Reservation. 30 refs., 7 figs., 12 tabs

Monitoring of biofilm formation on different material surfaces of medical devices using hyperspectral imaging method

Science.gov (United States)

Kim, Do-Hyun; Kim, Moon S.; Hwang, Jeeseong

2012-03-01

Contamination of the inner surface of indwelling (implanted) medical devices by microbial biofilm is a serious problem. Some microbial bacteria such as Escherichia coli form biofilms that lead to potentially lifethreatening infections. Other types of medical devices such as bronchoscopes and duodenoscopes account for the highest number of reported endoscopic infections where microbial biofilm is one of the major causes for these infections. We applied a hyperspectral imaging method to detect biofilm contamination on the surface of several common materials used for medical devices. Such materials include stainless steel, titanium, and stainless-steeltitanium alloy. Potential uses of hyperspectral imaging technique to monitor biofilm attachment to different material surfaces are discussed.

Tritium surface loading due to contamination of rainwater from atmospheric release at NAPS (2011)

International Nuclear Information System (INIS)

Gautam, Y.P.; Sharma, Saivajay; Rao, K.S.; Singh, Bhikam; Kumar, Avinash; Ravi, P.M.

2012-01-01

Annual tritium (HTO) surface loading has been measured and calculated for the year 2011 within 0.8 km distance from 145 m high stack of Narora Atomic Power Station (NAPS) at eight locations in different directions. The technique for measured values consists of the summation of product of tritium concentration (Bq/l) in daily rainfall samples and daily rainfall (mm). Tritium surface loading studies at NAPS reveal that a fraction 1.01E-03 of total annual tritium released through stack gets deposited on the surface due to washout/rainout of plume within 0.8 km radial distance from stack. The range of deposition velocity, Vw (m.s -1 ) i.e., the ratio of annual tritium surface loading W (Bq. m -2 .s -1 ) and annual mean tritium concentration in air, c 0 (Bq.m -3 ) at three locations for the years 2011 is found to be 6.12E-04 to 2.89E-03. The average value for wet deposition velocity V w for NAPS site is estimated as 3.17E-03 m.s -1 . (author)

Release of cadmium in contaminated paddy soil amended with NPK fertilizer and lime under water management.

Science.gov (United States)

Han, Xiao-Qing; Xiao, Xi-Yuan; Guo, Zhao-Hui; Xie, Ye-Hua; Zhu, Hui-Wen; Peng, Chi; Liang, Yu-Qin

2018-05-03

Agricultural soils contaminated with cadmium (Cd) pose a risk to receiving surface water via drainage or runoff. A 90-day laboratory incubation experiment was conducted to investigate the release characteristics and transformation of Cd from contaminated paddy soil amended with agrochemical (NPK fertilizer) and lime (L) under water management regimes of continuous flooding (F) and drying-wetting cycles (DW). The result showed that the dissolved Cd concentrations in overlying water of the fertilizer treatment under flooding (NPK+F) and drying-wetting (NPK+DW) reached up to 81.0 μg/L and 276 μg/L, and were much higher than that from the corresponding controls without NPK fertilizer addition at the end of experiment. The Cd concentration showed significantly negative correlation with overlying water pH, but positive correlation with soil redox potential and concentrations of dissolved total nitrogen, sulfate and manganese in overlying water (P < 0.05), indicating that drying-wetting cycles and N fertilizer addition may enhance soil Cd release. The Cd concentrations in overlying water from all treatments except NPK+L+F treatment exceeded the Cd threshold limit of Chinese Environmental Quality Standards for Surface Water (10 μg/L Grade V) and poses potential risk to surface water quality. Meanwhile, the proportion of Cd in the acid-soluble fraction from all incubated soil except NPK+L+F treatment increased compared to before incubation. The results indicated that continuous flooding was a reasonable water management candidate coupled with lime addition for immobilizing soil Cd. Copyright © 2018 Elsevier Inc. All rights reserved.

Dry washing: the solution for contaminated liquid effluent releases

International Nuclear Information System (INIS)

L'homme, D.; Trambouze, P.

1998-01-01

The release of wash water used for contaminated garments poses an ever-increasing problem on nuclear sites. Even though the radioactivity is low, it mixes with organic compounds, thus polluting a large quantity of liquid effluents. In many cases, several thousands of m 3 /year per nuclear site are produced, which at times represents more than 30% of the volume of total releases. The conventional dry cleaning process is not a viable option, given that repeated washing cause clothes to fade and the odors are rot removed completely. In order to eliminate releases, STMI has developed, after several years of research with the Technological University of Compiegne, France, a solvent dry washing process for garments used in the nuclear industry. (author)

Body-surface contamination monitoring preparatory to monitoring for internal contamination

International Nuclear Information System (INIS)

Schlueter, W.; Klucke, H.

1980-01-01

Measurements in the whole-body counter of the SAAS are routinely preceded by a thorough inspection of the patients for body-surface contamination to protect the sensitive counting equipment against becoming contaminated and to avoid a falsified indication of incorporated radionuclides. The measuring system employed for these examinations is described. (author)

Efficient prion disease transmission through common environmental materials.

Science.gov (United States)

Pritzkow, Sandra; Morales, Rodrigo; Lyon, Adam; Concha-Marambio, Luis; Urayama, Akihiko; Soto, Claudio

2018-03-02

Prion diseases are a group of fatal neurodegenerative diseases associated with a protein-based infectious agent, termed prion. Compelling evidence suggests that natural transmission of prion diseases is mediated by environmental contamination with infectious prions. We hypothesized that several natural and man-made materials, commonly found in the environments of wild and captive animals, can bind prions and may act as vectors for disease transmission. To test our hypothesis, we exposed surfaces composed of various common environmental materials ( i.e. wood, rocks, plastic, glass, cement, stainless steel, aluminum, and brass) to hamster-adapted 263K scrapie prions and studied their attachment and retention of infectivity in vitro and in vivo Our results indicated that these surfaces, with the sole exception of brass, efficiently bind, retain, and release prions. Prion replication was studied in vitro using the protein misfolding cyclic amplification technology, and infectivity of surface-bound prions was analyzed by intracerebrally challenging hamsters with contaminated implants. Our results revealed that virtually all prion-contaminated materials transmitted the disease at high rates. To investigate a more natural form of exposure to environmental contamination, we simply housed animals with large contaminated spheres made of the different materials under study. Strikingly, most of the hamsters developed classical clinical signs of prion disease and typical disease-associated brain changes. Our findings suggest that prion contamination of surfaces commonly present in the environment can be a source of disease transmission, thus expanding our understanding of the mechanisms for prion spreading in nature. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

Comparative Evaluation of Fluoride Releasing Ability of Various Restorative Materials after the Application of Surface Coating Agents - An In-vitro Study.

Science.gov (United States)

Kishore, Gvs; Sai-Sankar, A J; Pratap-Gowd, Mjs; Sridhar, M; Pranitha, Kakarla; Sai-Krishna, V S

2016-12-01

Fluoride plays a key role in prevention of dental caries and is also an essential element for oral health promotion both in children and adults. The aim of the present study was to evaluate the effect of surface coating (petroleum jelly, G-Coat Plus) on the fluoride releasing property of conventional Glass Ionomer Cement (GIC) and Zirconomer. A total of 30 disk shaped brass mold specimens (6±0.1mm in diameter and 2±0.1mm thickness) for each test group were fabricated with conventional GIC (Group A) and Zirconomer (Group B). These test groups were further divided into three subgroups of 10 each. The unprotected specimens act as control (Group A1 and B1), G-Coat Plus specimens as (Group A2 and B2) and for the remaining specimens petroleum jelly was applied (Group A3 and B3). Fluoride ion concentration was measured with a combination of fluoride ion specific electrode and ion analyzer for every 24 hours for 15 days. The data was statistically analyzed using Kruskal Wallis and Mann-Whitney U test. The Group B released significantly more fluoride than Group A. Among all the subgroups the greatest amount of fluoride was released from Group B1, in the first 24 hours followed by A1 and B2. The least was observed on 15 th day with Group B3 and A3. Both the tested materials (GIC and Zirconomer) used in the study exhibited fluoride release whether protected or unprotected with surface coating. Though there was a difference between the groups, the pattern of fluoride release was similar and continuous throughout the study period i.e., first the initial burst followed by sustained release. The results revealed Zirconomer released more fluoride and is comparable to conventional GIC.

Release of fission products from contaminated sodium fires

International Nuclear Information System (INIS)

Jordan, S.

1976-01-01

Leaks in the primary coolant system of a LMFBR and also serious incidents with tank rupture may entail the escape of fission products into the containment of the reactor. For incident analysis it is important to know the retention capability of sodium for the different fission products. The release of cesium and strontium from pools contaminated with 100 to 1000 ppM was investigated by experiments. The cesium content of airborne aerosols depends on oxygen concentration: at 21 percent oxygen concentration the Cs content of sodium-oxide aerosols is 3 times and at 0.5 percent 15 times as high as the initial Cs concentration in the pool. Strontium content of aerosols over burning contaminated sodium pools is 10 3 times smaller than the strontium pool concentration

Determination of the long-term release of metal(loid)s from construction materials using DGTs.

Science.gov (United States)

Schmukat, A; Duester, L; Ecker, D; Heininger, P; Ternes, T A

2013-09-15

Long-term leaching experiments are crucial to estimate the potential release of dangerous substances from construction materials. The application of Diffuse Gradients in Thin film (DGT) in static-batch experiments was tested to study the long-term release of metal(loid)s from construction materials for hydraulic engineering, for half a year. Long-term release experiments are essential to improve calculations of the life-time release for this materials. DGTs in batch experiments were found to be a space and labour efficient application, which enabled (i) to study, in a non-invasive manner, the total release of nine metal(loid)s for half a year, (ii) to differentiate between release mechanisms and (iii) to study mechanisms which were contrary to the release or caused experimental artefacts in the batch experiments. For copper slag (test material) it was found that eight metal(loid)s were released over the whole time period of 184 d. Cu, Ni and Pb were found to be released, predominantly caused by (the) weathering of sulphide minerals. Only for Zn a surface depletion mechanism was identified. The results from the long-term batch experiments deliver new information on the release of metal(loid)s during the life cycle of construction materials with regard to river basin management objectives. Copyright © 2013 Elsevier B.V. All rights reserved.

Contaminations of inner surface of magnesium fluoride windows in the `Expose-R' experiment on the International Space Station

Science.gov (United States)

Skurat, V. E.

2017-10-01

A series of experiments was carried out previously on board of the International Space Station in `EXPOSE-R', a multi-user expose facility, provided by European Space Agency attached to the external surface of the Russian Segment. In one experiment, spores of microorganisms and species of higher plant seeds, in heat-sealed polymer bags were irradiated by solar radiation passed through MgF2 windows in a high space vacuum. After sample exposure, it was found that in many cases the inner surfaces of windows were contaminated. Analysis of the contamination revealed the presence of chemical groups CH2, CH3, NH, OH, C═O, Si-CH3 (Demets et al. in 2015). Their presence in deposits was explained by photofixation of gaseous precursors - some of the vapours of glues and additives in polymeric materials in the core facility of `Expose-R'. Carbon-, oxygen- and silicon-containing groups may be deposited from outer intrinsic atmosphere. This atmosphere is connected with sample compartments and core facility. However, the presence of NH groups on inner surfaces of windows was not expected. This paper shows that the process responsible for carbon-, nitrogen- and oxygen-containing group formation can be a photopolymerization of caprolactam, which is released from the outer Nylon 6 layer of polymer bags under Solar vacuum ultraviolet radiation.

Simulating Exposure Concentrations of Engineered Nanomaterials in Surface Water Systems: Release of WASP8

Science.gov (United States)

Knightes, C. D.; Bouchard, D.; Zepp, R. G.; Henderson, W. M.; Han, Y.; Hsieh, H. S.; Avant, B. K.; Acrey, B.; Spear, J.

2017-12-01

The unique properties of engineered nanomaterials led to their increased production and potential release into the environment. Currently available environmental fate models developed for traditional contaminants are limited in their ability to simulate nanomaterials' environmental behavior. This is due to an incomplete understanding and representation of the processes governing nanomaterial distribution in the environment and by scarce empirical data quantifying the interaction of nanomaterials with environmental surfaces. The well-known Water Quality Analysis Simulation Program (WASP) was updated to incorporate nanomaterial-specific processes, specifically hetero-aggregation with particulate matter. In parallel with this effort, laboratory studies were used to quantify parameter values parameters necessary for governing processes in surface waters. This presentation will discuss the recent developments in the new architecture for WASP8 and the newly constructed Advanced Toxicant Module. The module includes advanced algorithms for increased numbers of state variables: chemicals, solids, dissolved organic matter, pathogens, temperature, and salinity. This presentation will focus specifically on the incorporation of nanomaterials, with the applications of the fate and transport of hypothetical releases of Multi-Walled Carbon Nanotubes (MWCNT) and Graphene Oxide (GO) into the headwaters of a southeastern US coastal plains river. While this presentation focuses on nanomaterials, the advanced toxicant module can also simulate metals and organic contaminants.

Dose-rate conversion factors for external exposure to photon and electron radiation from radionuclides occurring in routine releases from nuclear fuel cycle facilities

International Nuclear Information System (INIS)

Kocher, D.C.

1980-01-01

Dose-rate conversion factors for external exposure to photon and electron radiation are calculated for 240 radionuclides of potential importance in routine releases from nuclear fuel cycle facilities. Exposure modes considered are immersion in contaminated air, immersion in contaminated water, and irradiation from a contaminated ground surface. For each exposure mode, dose-rate conversion factors for photons and electrons are calculated for tissue-equivalent material at the body surface of an exposed individual. Dose-rate conversion factors for photons only are calculated for 22 body organs. (author)

MERCURY CONTAMINATED MATERIAL DECONTAMINATION METHODS: INVESTIGATION AND ASSESSMENT; TOPICAL

International Nuclear Information System (INIS)

M.A. Ebadian, Ph.D.

2001-01-01

Over the years mercury has been recognized as having serious impacts on human health and the environment. This recognition has led to numerous studies that deal with the properties of various mercury forms, the development of methods to quantify and speciate the forms, fate and transport, toxicology studies, and the development of site remediation and decontamination technologies. This report reviews several critical areas that will be used in developing technologies for cleaning mercury from mercury-contaminated surfaces of metals and porous materials found in many DOE facilities. The technologies used for decontamination of water and mixed wastes (solid) are specifically discussed. Many technologies that have recently appeared in the literature are included in the report. Current surface decontamination processes have been reviewed, and the limitations of these technologies for mercury decontamination are discussed. Based on the currently available technologies and the processes published recently in the literature, several processes, including strippable coatings, chemical cleaning with iodine/iodide lixiviant, chemisorbing surface wipes with forager sponge and grafted cotton, and surface/pore fixation through amalgamation or stabilization, have been identified as potential techniques for decontamination of mercury-contaminated metal and porous surfaces. Their potential merits and applicability are discussed. Finally, two processes, strippable coatings and chemical cleaning with iodine/iodide lixiviant, were experimentally investigated in Phase II of this project

"Effect of nano-filled surface coating agent on fluoride release from conventional glass ionomer cement: an in vitro trial".

Science.gov (United States)

Tiwari, S; Nandlal, B

2013-01-01

To overcome the drawbacks of glass ionomer cement of sensitivity to initial desiccation and moisture contamination the use of surface coating agent is recommended. The search in this area led to invent of use of nanofillers in surface coating agent, but its effect on fluoride release is not clear. The aim of this study is to evaluate and compare the fluoride release from conventional glass ionomer cement with and without surface coating agent. This in vitro study comprised of total 80 samples (40 samples of each with and without surface coating). Specimens were prepared, G coat plus was applied and light cured. Fluoride release of the sample was measured every 24 h for 7 days and weekly from 7th to 21 st day using Sension4 pH/ISE/MV Meter. Descriptive Statistics, Repeated Measure ANOVA, Paired Sample t-test, Independent Sample t-test, Scheffe post hoc test. Mean values clearly reveal a significant decrease in the fluoride release from day 1 to day 21 for both groups. Non-coated group released significantly more fluoride than surface coated group (Pagent will reduce the amount of fluoride released into oral environment as compared to non-coated group and at the same time releasing fluoride into surrounding cavity walls to create zones of inhibition into the cavity floor to help internal remineralization.

A review of biochars' potential role in the remediation, revegetation and restoration of contaminated soils

Energy Technology Data Exchange (ETDEWEB)

Beesley, Luke, E-mail: luke.beesley@hutton.ac.uk [James Hutton Institute, Craigiebuckler, Aberdeen AB15 8QH (United Kingdom); Moreno-Jimenez, Eduardo [Departamento de Quimica Agricola, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Gomez-Eyles, Jose L. [Department of Civil and Environmental Engineering, University of Maryland Baltimore County, Baltimore, MD 21250 (United States); Harris, Eva; Robinson, Brett [Department of Soil and Physical Sciences, Lincoln University, Lincoln 7647 (New Zealand); Sizmur, Tom [Soil Research Centre, Department of Geography and Environmental Science, University of Reading, Whiteknights, Reading RG6 6DW (United Kingdom)

2011-12-15

Biochars are biological residues combusted under low oxygen conditions, resulting in a porous, low density carbon rich material. Their large surface areas and cation exchange capacities, determined to a large extent by source materials and pyrolysis temperatures, enables enhanced sorption of both organic and inorganic contaminants to their surfaces, reducing pollutant mobility when amending contaminated soils. Liming effects or release of carbon into soil solution may increase arsenic mobility, whilst low capital but enhanced retention of plant nutrients can restrict revegetation on degraded soils amended only with biochars; the combination of composts, manures and other amendments with biochars could be their most effective deployment to soils requiring stabilisation by revegetation. Specific mechanisms of contaminant-biochar retention and release over time and the environmental impact of biochar amendments on soil organisms remain somewhat unclear but must be investigated to ensure that the management of environmental pollution coincides with ecological sustainability. - Highlights: > Biochars can reduce mobilities of some organic and inorganic pollutants in soil. > Source material and production conditions influence pollutant retention. > Highly alkaline pH and water soluble carbon can undesirably mobilise some elements. > Large surface area may be toxic to soil fauna but create microbial niches. > Efficacy of biochar may depend on other organic materials applied in combination. - Biochars can reduce the mobility and impact of some soil pollutants but, if applied alone, may fail to support soil restoration, revegetation and hence ecologically circumspect remediation.

Harvesting contaminants from liquid

Science.gov (United States)

Simpson, John T.; Hunter, Scott R.

2016-05-31

Disclosed are examples of apparatuses for evaporative purification of a contaminated liquid. In each example, there is a vessel for storing the contaminated fluid. The vessel includes a surface coated with a layer of superhydrophobic material and the surface is at least partially in contact with the contaminated liquid. The contaminants do not adhere to the surface as the purified liquid evaporates, thus allowing the contaminants to be harvested.

Monitoring of tritium-contaminated surfaces, including skin

International Nuclear Information System (INIS)

Surette, R.A.; Wood, M.J.

1994-05-01

We have examined various commercially available tritium surface contamination monitors along with different swipe media and techniques for direct and indirect (swipe) monitoring of contaminated surfaces, including skin. None of the methods or instruments evaluated were more sensitive than the swipe and liquid scintillation counting (LSC) method. Swipe measurements with open-window proportional counters were, in general, less than half as sensitive as LSC, but have the advantages of having the results available almost immediately, and no sample preparation is required. The Nuclear Measurement Corporation's PC-55 is the most suitable instrument we tested for the analysis of routine swipe measurement. The PC-55 was about one third as sensitive as LSC when used with Ontario Hydro filter paper swipe media. Surface contamination measurement results can be obtained within minutes using the PC-55, compared to hours using LSC. The selection of swipe media for use with proportional counter-based instruments is critical. A medium that is electrically insulating can develop an electrostatic charge on its surface; this may alter the field gradient in the detector and may adversely influence the results. Although the PC-55 is sufficiently sensitive and very convenient, operational experience with the instrument is needed before recommending that it replace current LSC methods. The PC-55's susceptibility to internal tritium contamination may limit its practical usefulness. Because of the complexity of using live animals to evaluate direct and indirect methods for assessing skin contamination, pig skin was investigated as a possible substitute. We concluded that, for the first few hours post-exposure, pig skin mimics the kinetics of animal skin that has contacted a tritium-contaminated surface. (author). 30 refs., 1 tab., 7 figs

Occurrence of Surface Water Contaminations: An Overview

Science.gov (United States)

Shahabudin, M. M.; Musa, S.

2018-04-01

Water is a part of our life and needed by all organisms. As time goes by, the needs by human increased transforming water quality into bad conditions. Surface water contaminated in various ways which is pointed sources and non-pointed sources. Pointed sources means the source are distinguished from the source such from drains or factory but the non-pointed always occurred in mixed of elements of pollutants. This paper is reviewing the occurrence of the contaminations with effects that occurred around us. Pollutant factors from natural or anthropology factors such nutrients, pathogens, and chemical elements contributed to contaminations. Most of the effects from contaminated surface water contributed to the public health effects also to the environments.

Inclusion of cefalexin in SBA-15 mesoporus material and release property

International Nuclear Information System (INIS)

Zhai, Qing-Zhou

2012-01-01

SBA-15 (Santa Barbara Amorphous-15) is a high ordered mesoporous material. It has the advantages of a non-toxic property, good hydrothermal stability and thermal stability, etc. Inside inner surface a lot of silanols exist. Pore diameter size is uniform and pore size distribution is narrow. This structural feature makes SBA-15 have a higher loading drug amount and be able to effectively extend the drug release cycle. In this paper, polyethylene glycol-block-polypropylene glycol-block-polyethylene glycol was used as template and tetraethyl orthosilicate was used as silica source to prepare SBA-15 by hydrothermal synthesis method. Cefalexin was included in SBA-15 and the included cefalexin drug content was 158.72 mg/g. The composite materials were characterized by using chemical analysis, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared (IR) spectroscopy, and low temperature nitrogen adsorption–desorption. The results showed that cefalexin had been successfully included in host SBA-15 pore channels. Rational analyses of the release processes of cefalexin drug from the pores of SBA-15 to the simulated body fluid, simulated gastric juice and simulated intestinal fluid were made and sustained-release effects of the drug in complex system were studied. The results showed that in simulated body fluid within 1–5 h cefalexin was fast released and the cumulative release reached 50.00% at 5 h. In 15–20 h, the sustained release speed of cefalexin drug in the composite material decreased and the sustained-release cumulative amount reached 99.87% at 20 h. The release of cefalexin was basically complete. In simulated gastric fluid, composite material sustained-release ended at 4 h, the cumulative sustained release ratio reaching 26.10%. In simulated gastric fluid, the sustained-release was complete at 7 h, the cumulative sustained release ratio reaching 32.46%. The composite material of SBA-15 and cefalexin

The impact of steam generator replacement on PWR primary system contamination

International Nuclear Information System (INIS)

Dacquait, F.; Marteau, H.; Guinard, L.; Ranchoux, G.; Taunier, S.; Wintergerst, M.; Bretelle, J.L.; Rocher, A.

2010-01-01

This paper analyses the impact of Steam Generator Replacement (SGR) on PWR primary circuit contamination. It presents a comparison of the activities deposited inside the primary system and released during refuelling outages after SGR with three different SG tube alloys (600, 690 and 800) and different SG tube manufacturing processes. A SGR has a great impact on the primary system contamination. After SGR, whatever the SG tube material is, the typical variations are the following: The 58 Co contamination increases for 1 to 3 cycles, and then decreases to very low levels in some cases, mainly depending on the manufacturing process of the replacement SG tubes; The 60 Co Co contamination tends to decrease on the primary coolant pipes and increases by a lower rate on the new SG tubes. This analysis highlights the importance on contamination levels after SGR of both the corrosion product deposits on the primary surfaces before SGR and the surface finish of the SG tubes related to their manufacturing process. (author)

Statistical sampling method for releasing decontaminated vehicles

International Nuclear Information System (INIS)

Lively, J.W.; Ware, J.A.

1996-01-01

Earth moving vehicles (e.g., dump trucks, belly dumps) commonly haul radiologically contaminated materials from a site being remediated to a disposal site. Traditionally, each vehicle must be surveyed before being released. The logistical difficulties of implementing the traditional approach on a large scale demand that an alternative be devised. A statistical method (MIL-STD-105E, open-quotes Sampling Procedures and Tables for Inspection by Attributesclose quotes) for assessing product quality from a continuous process was adapted to the vehicle decontamination process. This method produced a sampling scheme that automatically compensates and accommodates fluctuating batch sizes and changing conditions without the need to modify or rectify the sampling scheme in the field. Vehicles are randomly selected (sampled) upon completion of the decontamination process to be surveyed for residual radioactive surface contamination. The frequency of sampling is based on the expected number of vehicles passing through the decontamination process in a given period and the confidence level desired. This process has been successfully used for 1 year at the former uranium mill site in Monticello, Utah (a CERCLA regulated clean-up site). The method forces improvement in the quality of the decontamination process and results in a lower likelihood that vehicles exceeding the surface contamination standards are offered for survey. Implementation of this statistical sampling method on Monticello Projects has resulted in more efficient processing of vehicles through decontamination and radiological release, saved hundreds of hours of processing time, provided a high level of confidence that release limits are met, and improved the radiological cleanliness of vehicles leaving the controlled site

UNDERWATER COATINGS FOR CONTAMINATION CONTROL

International Nuclear Information System (INIS)

Julia L. Tripp; Kip Archibald; Ann Marie Phillips; Joseph Campbell

2004-01-01

The Idaho National Laboratory (INL) deactivated several aging nuclear fuel storage basins. Planners for this effort were greatly concerned that radioactive contamination present on the basin walls could become airborne as the sides of the basins became exposed during deactivation and allowed to dry after water removal. One way to control this airborne contamination was to fix the contamination in place while the pool walls were still submerged. There are many underwater coatings available on the market for marine, naval and other applications. A series of tests were run to determine whether the candidate underwater fixatives were easily applied and adhered well to the substrates (pool wall materials) found in INL fuel pools. Lab-scale experiments were conducted by applying fourteen different commercial underwater coatings to four substrate materials representative of the storage basin construction materials, and evaluating their performance. The coupons included bare concrete, epoxy painted concrete, epoxy painted carbon steel, and stainless steel. The evaluation criteria included ease of application, adherence to the four surfaces of interest, no change on water clarity or chemistry, non-hazardous in final applied form and be proven in underwater applications. A proprietary two-part, underwater epoxy owned by S. G. Pinney and Associates was selected from the underwater coatings tested for application to all four pools. Divers scrubbed loose contamination off the basin walls and floors using a ship hull scrubber and vacuumed up the sludge. The divers then applied the coating using a special powered roller with two separate heated hoses that allowed the epoxy to mix at the roller surface was used to eliminate pot time concerns. The walls were successfully coated and water was removed from the pools with no detectable airborne contamination releases

Methods for the calculation of derived working limits for surface contamination by low-toxicity radionuclides

International Nuclear Information System (INIS)

Gibson, J.A.B.; Wrixon, A.D.

1979-01-01

Surface contamination is often measured as an indication of the general spread of radioactive contamination in a particular place. Derived working limits, (DWLs) for surface contamination provide figures against which to assess the significance of measurements. Derived working limits for surface contamination were first established for use in the nuclear energy industry. They were designed to cope with a wide range of unspecified radionuclides and were therefore based on the assumption that the contamination was due to the presence of the most hazardous radionuclides, e.g. 90 Sr, 210 Pb, 226 Ra and 239 Pu. While this assumption may still be appropriate when the radionuclide mixture is unknown, there are now many specialized uses of particular low-toxicity radionuclides in universities, hospitals and general industry. If it is known that only a particular radionuclide is present, the general DWL can be replaced by a more specific value. The methods for calculating DWLs for some of the more commonly employed low-toxicity radionuclides are described. The exposure pathways considered are (a) external radiation of the skin and inhalation of airborne material from contaminated surfaces in active areas; (b) external irradiation of the skin and ingestion from contaminated skin. Some consideration is given to the effect of the revised dose equivalent limits in the most recent recommendations of ICRP. (author)

Indoor and Outdoor Surface-Growing Fungi Contamination at Higher Institutional Buildings in a Malaysian University

Science.gov (United States)

Er, C. M.; Sunar, N. M.; Leman, A. M.; Khalid, A.; Ali, R.; Zaidi, E.; Azhar, A. T. S.

2018-04-01

Surface-growing indoor and outdoor fungi were assessed using swabbing method to investigate the indoor contamination. The painted wall surface samples were collected from two institutional buildings (B1 and B2) of a university in southern Peninsular Malaysia; indoors and outdoors. The mould concentrations varied widely between indoor and outdoor surface samples of both buildings. The total indoor surface-growing mould concentration (8776.49 CFU/cm2) is significantly higher (pair quality parameters (relative humidity, temperature and air velocity) were also measured indoors and outdoors during the study and violation of the guideline provided by ICOP-IAQ 2010 were proven in indoor environment in both buildings. The results of this assessment showed that the indoor environments of both institutional buildings were contaminated by the surface-growing mould. It also suggested the faulty designs and/or usages of building material in these institutional buildings contributed toward the contamination. An innovative solution is needed to correct the problems.

Contaminant Release from Residual Waste in Single Shell Tanks at the Hanford Site, Washington, USA - 9276

International Nuclear Information System (INIS)

Cantrell, Kirk J.; Krupka, Kenneth M.; Deutsch, William J.; Lindberg, Michael J.

2009-01-01

Determinations of elemental and solid-phase compositions, and contaminant release studies have been applied in an ongoing study of residual tank wastes (i.e., waste remaining after final retrieval operations) from five of 149 underground single-shell storage tanks (241-C-103, 241-C-106, 241-C-202, 241-C-203, and 241-S-112) at the U.S. Department of Energy's Hanford Site in Washington State. This work is being conducted to support performance assessments that will be required to evaluate long-term health and safety risks associated with tank site closure. The results of studies completed to date show significant variability in the compositions, solid phase properties, and contaminant release characteristics from these residual tank wastes. This variability is the result of differences in waste chemistry/composition of wastes produced from several different spent fuel reprocessing schemes, subsequent waste reprocessing to remove certain target constituents, tank farm operations that concentrated wastes and mixed wastes between tanks, and differences in retrieval processes used to remove the wastes from the tanks. Release models were developed based upon results of chemical characterization of the bulk residual waste, solid-phase characterization (see companion paper 9277 by Krupka et al.), leaching and extraction experiments, and geochemical modeling. In most cases empirical release models were required to describe contaminant release from these wastes. Release of contaminants from residual waste was frequently found to be controlled by the solubility of phases that could not be identified and/or for which thermodynamic data and/or dissolution rates have not been measured. For example, significant fractions of Tc-99, I-129, and Cr appear to be coprecipitated at trace concentrations in metal oxide phases that could not be identified unambiguously. In the case of U release from tank 241-C-103 residual waste, geochemical calculations indicated that leachate

Developments in surface contamination and cleaning fundamentals and applied aspects

CERN Document Server

Kohli, Rajiv

2015-01-01

Developments in Surface Contamination and Cleaning, Vol. 1: Fundamentals and Applied Aspects, Second Edition, provides an excellent source of information on alternative cleaning techniques and methods for characterization of surface contamination and validation. Each volume in this series contains a particular topical focus, covering the key techniques and recent developments in the area. This volume forms the heart of the series, covering the fundamentals and application aspects, characterization of surface contaminants, and methods for removal of surface contamination. In addition, new cleaning techniques effective at smaller scales are considered and employed for removal where conventional cleaning techniques fail, along with new cleaning techniques for molecular contaminants. The Volume is edited by the leading experts in small particle surface contamination and cleaning, providing an invaluable reference for researchers and engineers in R&D, manufacturing, quality control, and procurement specific...

Hanford tank residual waste - Contaminant source terms and release models

International Nuclear Information System (INIS)

Deutsch, William J.; Cantrell, Kirk J.; Krupka, Kenneth M.; Lindberg, Michael L.; Jeffery Serne, R.

2011-01-01

Highlights: → Residual waste from five Hanford spent fuel process storage tanks was evaluated. → Gibbsite is a common mineral in tanks with high Al concentrations. → Non-crystalline U-Na-C-O-P ± H phases are common in the U-rich residual. → Iron oxides/hydroxides have been identified in all residual waste samples. → Uranium release is highly dependent on waste and leachant compositions. - Abstract: Residual waste is expected to be left in 177 underground storage tanks after closure at the US Department of Energy's Hanford Site in Washington State, USA. In the long term, the residual wastes may represent a potential source of contamination to the subsurface environment. Residual materials that cannot be completely removed during the tank closure process are being studied to identify and characterize the solid phases and estimate the release of contaminants from these solids to water that might enter the closed tanks in the future. As of the end of 2009, residual waste from five tanks has been evaluated. Residual wastes from adjacent tanks C-202 and C-203 have high U concentrations of 24 and 59 wt.%, respectively, while residual wastes from nearby tanks C-103 and C-106 have low U concentrations of 0.4 and 0.03 wt.%, respectively. Aluminum concentrations are high (8.2-29.1 wt.%) in some tanks (C-103, C-106, and S-112) and relatively low ( 2 -saturated solution, or a CaCO 3 -saturated water. Uranium release concentrations are highly dependent on waste and leachant compositions with dissolved U concentrations one or two orders of magnitude higher in the tests with high U residual wastes, and also higher when leached with the CaCO 3 -saturated solution than with the Ca(OH) 2 -saturated solution. Technetium leachability is not as strongly dependent on the concentration of Tc in the waste, and it appears to be slightly more leachable by the Ca(OH) 2 -saturated solution than by the CaCO 3 -saturated solution. In general, Tc is much less leachable (<10 wt.% of the

Process for affixing radioactive contamination on contaminated materials or wastes. Its application

International Nuclear Information System (INIS)

Aubouin, Guy; Aude, Georges; Tassigny, Christian de.

1982-01-01

The invention concerns a process for affixing radioactive contamination on materials or waste matter in order to ensure that the materials are transferred in complete safety or to package them when their activity is low. Under this process at least one coat of a resin polymerizable at ambient temperature, for example an epoxy resin, a polyester resin, a vinyl resin or a mixture of thermohardening resin and thermoplastic resin, is sprayed on to the contaminated material part by means of an electrostatic gun [fr

A simplified ALARA approach to demonstration of compliance with surface contaminated object regulatory requirements

International Nuclear Information System (INIS)

Pope, R.B.; Shappert, L.B.; Michelhaugh, R.D.; Boyle, R.W.; Cook, J.C.

1998-02-01

The US Department of Transportation (DOT) and the US Nuclear Regulatory Commission (NRC) have jointly prepared a comprehensive set of draft guidance for consignors and inspectors to use when applying the newly imposed regulatory requirements for low specific activity (LSA) material and surface contaminated objects (SCOs). The guidance is being developed to facilitate compliance with the new LSA material and SCO requirements, not to impose additional requirements. These new requirements represent, in some areas, significant departures from the manner in which packaging and transportation of these materials and objects were previously controlled. On occasion, it may be appropriate to use conservative approaches to demonstrate compliance with some of the requirements, ensuring that personnel are not exposed to radiation at unnecessary levels, so that exposures are kept as low as reasonably achievable (ALARA). In the draft guidance, one such approach would assist consignors preparing a shipment of a large number of SCOs in demonstrating compliance without unnecessarily exposing personnel. In applying this approach, users need to demonstrate that four conditions are met. These four conditions are used to categorize non-activated, contaminated objects as SCO-2. It is expected that, by applying this approach, it will be possible to categorize a large number of small contaminated objects as SCO-2 without the need for detailed, quantitative measurements of fixed, accessible contamination, or of total (fixed and non-fixed) contamination on inaccessible surfaces. The method, which is based upon reasoned argument coupled with limited measurements and the application of a sum of fractions rule, is described and examples of its use are provided

Monitoring of tritium-contaminated surfaces, including skin

Energy Technology Data Exchange (ETDEWEB)

Surette, R A; Wood, M J

1994-05-01

We have examined various commercially available tritium surface contamination monitors along with different swipe media and techniques for direct and indirect (swipe) monitoring of contaminated surfaces, including skin. None of the methods or instruments evaluated were more sensitive than the swipe and liquid scintillation counting (LSC) method. Swipe measurements with open-window proportional counters were, in general, less than half as sensitive as LSC, but have the advantages of having the results available almost immediately, and no sample preparation is required. The Nuclear Measurement Corporation`s PC-55 is the most suitable instrument we tested for the analysis of routine swipe measurement. The PC-55 was about one third as sensitive as LSC when used with Ontario Hydro filter paper swipe media. Surface contamination measurement results can be obtained within minutes using the PC-55, compared to hours using LSC. The selection of swipe media for use with proportional counter-based instruments is critical. A medium that is electrically insulating can develop an electrostatic charge on its surface; this may alter the field gradient in the detector and may adversely influence the results. Although the PC-55 is sufficiently sensitive and very convenient, operational experience with the instrument is needed before recommending that it replace current LSC methods. The PC-55`s susceptibility to internal tritium contamination may limit its practical usefulness. Because of the complexity of using live animals to evaluate direct and indirect methods for assessing skin contamination, pig skin was investigated as a possible substitute. We concluded that, for the first few hours post-exposure, pig skin mimics the kinetics of animal skin that has contacted a tritium-contaminated surface. (author). 30 refs., 1 tab., 7 figs.

Conformation evolution of oil contaminants onto aluminum oxide surface in aqueous solution: The effect of surface coverage

Energy Technology Data Exchange (ETDEWEB)

Xie, Wenkun; Liu, Haitao, E-mail: xwk584523412@126.com; Sun, Yazhou; Fu, Hongya; Liang, Yingchun

2017-01-15

Highlights: • The dynamic conformational change of oil contaminations, at various surface coverages onto perfect α-Al{sub 2}O{sub 3}(0001) surface in aqueous solution is given. • The effect of surface coverage of oil molecules on the driving forces for the conformational change of oil contaminations is described. • The effect of interfacial water on the conformational change and even detachment of oil contaminations is considered. - Abstract: The microscopic conformational change process of oil contaminants adhered onto perfect α-Al{sub 2}O{sub 3} (0001) surface in aqueous solution was investigated by using all-atom classic molecular dynamics simulations. The change in removal mechanism of oil contaminants induced by surface coverage (surface area per molecule) was emphatically explored. Our simulation results strongly reveal that the increase in oil surface coverage induces an evident difference in microscopic detachment processes of oil contaminants. At a low surface coverage, oil contaminants can be thoroughly detached from solid surface. The whole detachment process could be divided into multi stages, including conformational change of oil contaminants on solid surface, dynamic motion of those in bulk solution and rapid migration of those from bulk solution to air/water interface. With surface coverage increasing, water diffusion becomes the key to induce conformational change and promote the detachment of oil contaminants. When oil surface coverage exceeds a threshold value, oil contaminants also undertake an evident conformational change process exhibiting typical characteristics but an incomplete detachment process occurs. All findings of the present study are helpful for the interpretation of the removal mechanism of oil contaminants on solid surface.

The estimation of areas of ground that may be contaminated after an accidental release of pollutant to the atmosphere

International Nuclear Information System (INIS)

Corbett, J.O.

1979-01-01

A method is developed for calculating the area of ground contaminated above a prescribed level after an accidental release of radioactivity or any other pollutant to the atmosphere. Numerical calculations are made for a wide range of releases, atmospheric conditions and rates of wet and dry deposition. It is shown that high atmospheric stability and rain both tend to maximize the area of significant contamination for most of the plausible range of releases. However, for very large hypothetical releases, dry conditions with an unstable atmosphere spread significant contamination furthest afield. (author)

Decontamination efficiency of a sheet of vinyl wall paper as a surface material in radioisotope laboratory

International Nuclear Information System (INIS)

Furukawa, Kazuhiko; Funadera, Kanako

1989-01-01

It has long been desired to prevent surface materials from cracking in a radioisotope laboratory. We applied a sheet of nonflammable wall paper, vinyl cloth, as a surface material to cover concrete wall. It was sufficiently resistant to the reinforced concrete wall cracking. The efficiency of the decontamination of the vinyl cloth was compared with those of stainless steel, iron and painted plates. The contamination and decontamination indices were determined in these surface materials after contamination with [ 32 P]orthophosphate (pH 3, 7 and 11) for 0 to 48 h. Both of the indices of the vinyl cloth were higher than those of the other materials. Further, it was confirmed that the vinyl cloth was resistant to acid and alkaline conditions and radioisotopes could not be permeable. The wipe off efficiency was also investigated in these materials by use of several decontamination detergents. In any reagents tested, the wipe of efficiency of the vinyl cloth was more than 80%. Thus, the vinyl cloth could be used for the surface material and is one of good surface materials in a radioisotope laboratory. (author)

Surface Contamination Monitor and Survey Information Management System

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-02-01

Shonka Research Associates, Inc.`s (SRA) Surface Contamination Monitor and Survey Information management System (SCM/SIMS) is designed to perform alpha and beta radiation surveys of floors and surfaces and document the measured data. The SRA-SCM/SIMS technology can be applied to routine operational surveys, characterization surveys, and free release and site closure surveys. Any large nuclear site can make use of this technology. This report describes a demonstration of the SRA-SCM/SIMS technology. This demonstration is part of the chicago Pile-5 (CP-5) Large-Scale Demonstration Project (LSDP) sponsored by the US Department of Energy (DOE), Office of Science and Technology (ST), Deactivation and Decommissioning Focus Area (DDFA). The objective of the LSDP is to select and demonstrate potentially beneficial technologies at the Argonne National Laboratory-East`s (ANL) CP-5 Research Reactor Facility. The purpose of the LSDP is to demonstrate that by using innovative and improved deactivation and decommissioning (D and D) technologies from various sources, significant benefits can be achieved when compared to baseline D and D technologies.

Surface Contamination Monitor and Survey Information Management System

International Nuclear Information System (INIS)

1998-02-01

Shonka Research Associates, Inc.'s (SRA) Surface Contamination Monitor and Survey Information management System (SCM/SIMS) is designed to perform alpha and beta radiation surveys of floors and surfaces and document the measured data. The SRA-SCM/SIMS technology can be applied to routine operational surveys, characterization surveys, and free release and site closure surveys. Any large nuclear site can make use of this technology. This report describes a demonstration of the SRA-SCM/SIMS technology. This demonstration is part of the chicago Pile-5 (CP-5) Large-Scale Demonstration Project (LSDP) sponsored by the US Department of Energy (DOE), Office of Science and Technology (ST), Deactivation and Decommissioning Focus Area (DDFA). The objective of the LSDP is to select and demonstrate potentially beneficial technologies at the Argonne National Laboratory-East's (ANL) CP-5 Research Reactor Facility. The purpose of the LSDP is to demonstrate that by using innovative and improved deactivation and decommissioning (D and D) technologies from various sources, significant benefits can be achieved when compared to baseline D and D technologies

Predicting the distribution of contamination from a chlorinated hydrocarbon release

Energy Technology Data Exchange (ETDEWEB)

Lupo, M.J. [K.W. Brown Environmental Services, College Station, TX (United States); Moridis, G.J. [Lawrence Berkeley Laboratory, Berkeley, CA (United States)

1995-03-01

The T2VOC model with the T2CG1 conjugate gradient package was used to simulate the motion of a dense chlorinated hydrocarbon plume released from an industrial plant. The release involved thousands of kilograms of trichloroethylene (TCE) and other chemicals that were disposed of onsite over a period of nearly twenty years. After the disposal practice ceased, an elongated plume was discovered. Because much of the plume underlies a developed area, it was of interest to study the migration history of the plume to determine the distribution of the contamination.

Source term estimation and the isotopic ratio of radioactive material released from the WIPP repository in New Mexico, USA

International Nuclear Information System (INIS)

Thakur, P.

2016-01-01

After almost 15 years of operations, the Waste Isolation Pilot Plant (WIPP) had one of its waste drums breach underground as a result of a runaway chemical reaction in the waste it contained. This incident occurred on February 14, 2014. Moderate levels of radioactivity were released into the underground air. A small portion of the contaminated underground air also escaped to the surface through the ventilation system and was detected approximately 1 km away from the facility. According to the source term estimation, the actual amount of radioactivity released from the WIPP site was less than 1.5 mCi. The highest activity detected on the surface was 115.2 μBq/m 3 for 241 Am and 10.2 μBq/m 3 for 239+240 Pu at a sampling station located 91 m away from the underground air exhaust point and 81.4 μBq/m 3 of 241 Am and 5.8 μBq/m 3 of 239+240 Pu at a monitoring station located approximately 1 km northwest of the WIPP facility. The dominant radionuclides released were americium and plutonium, in a ratio that matches the content of the breached drum. Air monitoring across the WIPP site intensified following the first reports of radiation detection underground to determine the extent of impact to WIPP personnel, the public, and the environment. In this paper, the early stage monitoring data collected by an independent monitoring program conducted by the Carlsbad Environmental Monitoring & Research Center (CEMRC) and an oversight monitoring program conducted by the WIPP's management and operating contractor, the Nuclear Waste Partnership (NWP) LLC were utilized to estimate the actual amount of radioactivity released from the WIPP underground. The Am and Pu isotope ratios were measured and used to support the hypothesis that the release came from one drum identified as having breached that represents a specific waste stream with this radionuclide ratio in its inventory. This failed drum underwent a heat and gas producing reaction that overpowered its vent and

Storage chamber for container of radiation-contaminated material

International Nuclear Information System (INIS)

Takakura, Masahide.

1996-01-01

The present invention concerns a storage chamber for containing radiation-contaminated materials in containing tubes and having cooling fluids circulated at the outer side of the containing tubes. The storage chamber comprises a gas supply means connected to the inside of the container tube for supplying a highly heat-conductive gas and a gas exhaustion means for discharging the gas present in the container tube. When containing vessels for radiation-contaminated materials are contained in the container tube, the gases present inside of the container tube is exhausted by means of the gas exhaustion means, and highly heat conductive gases are filled from the gas supply means to the space between the container tube and the containing vessels for the radiation-contaminated materials. When the temperature of the highly heat conductive gas is elevated due to the heat generation of the radiation-contaminated materials, the container tube is heated, and then cooled by the cooling fluid at the outer side of the container tube. In this case, the heat of the radiation-contaminated material-containing vessels is removed by the heat conduction by the highly heat conductive gas to reduce temperature gradient between the containing vessels and the containing tube. This can enhance the cooling effect. (T.M.)

Stimuli-Responsive Materials for Controlled Release Applications

KAUST Repository

Li, Song

2015-04-01

The controlled release of therapeutics has been one of the major challenges for scientists and engineers during the past three decades. To address this outstanding problem, the design and fabrication of stimuli-responsive materials are pursued to guarantee the controlled release of cargo at a specific time and with an accurate amount. Upon applying different stimuli such as light, magnetic field, heat, pH change, enzymes or redox, functional materials change their physicochemical properties through physical transformation or chemical reactions, allowing the release of payload agents on demand. This dissertation studied three stimuli-responsive membrane systems for controlled release from films of macro sizes to microcapsules of nano sizes. The first membrane system is a polymeric composite film which can decrease and sustain diffusion upon light irradiation. The photo-response of membranes is based on the photoreaction of cinnamic derivatives. The second one is composite membrane which can improve diffusion upon heating. The thermo-response of membranes comes from the volume phase transition ability of hydrogels. The third one is microcapsule which can release encapsulated agents upon light irradiation. The photo-response of capsules results from the photoreaction of nitrobenzyl derivatives. The study on these membrane systems reveals that stimuli-responsive release can be achieved by utilizing different functional materials on either macro or micro level. Based on the abundant family of smart materials, designing and fabricating stimuli-responsive systems shall lead to various advanced release processes on demand for biomedical applications.

Metals and metalloids treatment in contaminated neutral effluents using modified materials.

Science.gov (United States)

Calugaru, Iuliana Laura; Neculita, Carmen Mihaela; Genty, Thomas; Zagury, Gérald J

2018-04-15

Circumneutral surface water and groundwater can contain hazardous concentrations of metals and metalloids that can threaten organisms in surrounding ecosystems. Extensive research has been conducted over the past two decades to prevent, limit, and treat water pollution. Among the currently available treatment options is the use of natural and residual materials, which is generally regarded as effective and inexpensive. The modification of such materials enhances the removal capacity of metals and metalloids, as well as the physical and chemical stability of the materials and resulting sludge (after treatment). This paper reviews several modified materials that have produced and evaluated in the past twenty years to treat various contaminants in water under specific conditions. Important factors on performance improvement following the modifications are emphasized. Sorption capacity and kinetics, and element removal mechanisms are also discussed. Element recovery, material regeneration, water reuse, evaluation of treatment efficiency for real effluents are also considered, as well as the applicability of these materials in both active and passive treatment systems. Modified natural and residual materials are a promising option for the treatment of metals and metalloids in circumneutral contaminated waters. However, further research is necessary to evaluate their field-scale performance and to properly assess treatment costs. Copyright © 2018 Elsevier Ltd. All rights reserved.

System for removing contaminated surface layers

International Nuclear Information System (INIS)

Yoshikawa, Kozo.

1987-04-01

The object of the present invention is to offer a new type of useful decontamination system, with which the contaminated surface layers can be removed effectively by injection of such solid microparticles. Liquid carbon dioxide is passed from a liquid carbon dioxide tank via the carbon dioxide supply line into the system for injecting solid carbon dioxide particles. Part of the liquid carbon dioxide introduced into the system is converted to solid carbon dioxide particles by the temperature drop resulting from adiabatic expansion in the carbon dioxide expansion space of the injection system. The solid carbon dioxide particles reach the injection nozzle, which is connected through the expansion space. The carbon dioxide microparticles are further cooled and accelerated by nitrogen gas injected from the nitrogen gas nozzle at the tip of the nitrogen gas supply line, which is connected to a liquid nitrogen tank. The cooled and accelerated solid carbon dioxide microparticles are injected from the injection nozzle for the solid carbon dioxide and directed against the contaminated surface to be cleaned, and, as a result, the surface contamination is removed

Microbiological quality control of single-walled carbon-nanotubes-coated surfaces experimentally contaminated

International Nuclear Information System (INIS)

Natalizi, T.; Frioni, A.; Passeri, D.; Pantanella, F.

2013-01-01

The emergence of new nanotechnologies involves the spreading of nanoparticles in various fields of human life. Nanoparticles in general and, more specifically, carbon nanotubes have been adopted for many practical approaches i.e.: coatings for medical devices, food process industry and drug delivery. Humans will be increasingly exposed to nanoparticles but the susceptibility of nanostructured materials to microbial colonization in process of manufacturing and storage has not been thoroughly considered. Therefore, the microbiological quality control of nanoparticles plays a pivotal role. Different analytical methods have been attempted for detecting bacterial population contaminating a surface, but no one can be considered fully appropriate. Here, BioTimer Assay (BTA) and conventional sonication followed by colony forming units method (S-CFU) were applied for microbiological quality control of single-walled carbon nanotubes (SWCNTs)-coated surfaces experimentally contaminated with Streptococcus mutans and Pseudomonas aeruginosa. Our results demonstrated that S-CFU is unreliable to actually determine the number of bacteria, contaminating abiotic surfaces, as it does not detach all adherent bacteria and kills part of the bacterial population. Instead, BTA is a reliable method to enumerate bacteria colonizing SWCNTs-coated surfaces and can be considered a useful tool for microbiological quality control of nanomaterials for human use.

Plutonium contaminated materials research programme. Progress Report for 1983/84 from the Plutonium Contaminated Materials Working Party

International Nuclear Information System (INIS)

Higson, S.G.

1984-01-01

Plutonium contaminated material (PCM) is a generic term applied to a wide variety of materials which have become contaminated by plutonium compounds, by virtue of their use inside the primary containment of fuel cycle plants, but which generally have low beta gamma content. The report falls under the headings: introduction; organisation and role of the PCMWP; management practices; 1983/84 progress report (a) reduction of arisings; (b) plutonium measurement; (c) treatment of solid PCM; (d) treatment of alpha bearing liquid wastes; (e) actinide chemistry; (f) engineering objectives. (U.K.)

Polyphosphazine-based polymer materials

Science.gov (United States)

Fox, Robert V.; Avci, Recep; Groenewold, Gary S.

2010-05-25

Methods of removing contaminant matter from porous materials include applying a polymer material to a contaminated surface, irradiating the contaminated surface to cause redistribution of contaminant matter, and removing at least a portion of the polymer material from the surface. Systems for decontaminating a contaminated structure comprising porous material include a radiation device configured to emit electromagnetic radiation toward a surface of a structure, and at least one spray device configured to apply a capture material onto the surface of the structure. Polymer materials that can be used in such methods and systems include polyphosphazine-based polymer materials having polyphosphazine backbone segments and side chain groups that include selected functional groups. The selected functional groups may include iminos, oximes, carboxylates, sulfonates, .beta.-diketones, phosphine sulfides, phosphates, phosphites, phosphonates, phosphinates, phosphine oxides, monothio phosphinic acids, and dithio phosphinic acids.

REAL-TIME IDENTIFICATION AND CHARACTERIZATION OF ASBESTOS AND CONCRETE MATERIALS WITH RADIOACTIVE CONTAMINATION

International Nuclear Information System (INIS)

XU, X. George; Zhang, X.C.

2002-01-01

Concrete and asbestos-containing materials were widely used in DOE building construction in the 1940s and 1950s. Over the years, many of these porous materials have been contaminated with radioactive sources, on and below the surface. To improve current practice in identifying hazardous materials and in characterizing radioactive contamination, an interdisciplinary team from Rensselaer has conducted research in two aspects: (1) to develop terahertz time-domain spectroscopy and imaging system that can be used to analyze environmental samples such as asbestos in the field, and (2) to develop algorithms for characterizing the radioactive contamination depth profiles in real-time in the field using gamma spectroscopy. The basic research focused on the following: (1) mechanism of generating of broadband pulsed radiation in terahertz region, (2) optimal free-space electro-optic sampling for asbestos, (3) absorption and transmission mechanisms of asbestos in THz region, (4) the role of asbestos sample conditions on the temporal and spectral distributions, (5) real-time identification and mapping of asbestos using THz imaging, (7) Monte Carlo modeling of distributed contamination from diffusion of radioactive materials into porous concrete and asbestos materials, (8) development of unfolding algorithms for gamma spectroscopy, and (9) portable and integrated spectroscopy systems for field testing in DOE. Final results of the project show that the combination of these innovative approaches has the potential to bring significant improvement in future risk reduction and cost/time saving in DOE's D and D activities

Incident involving radioactive material at IAEA Safeguards Laboratory - No radioactivity released to environment

International Nuclear Information System (INIS)

2008-01-01

Full text: Pressure build-up in a small sealed sample bottle in a storage safe resulted in plutonium contamination of a storage room at about 02:30 today at the IAEA's Safeguards Analytical Laboratory in Seibersdorf. All indications are that there was no release of radioactivity to the environment. Further monitoring around the laboratory will be undertaken. No one was working in the laboratory at the time. The Laboratory's safety system detected plutonium contamination in the storage room where the safe was located and in two other rooms - subsequently confirmed by a team of IAEA radiation protection experts. The Laboratory is equipped with multiple safety systems, including an air-filtering system to prevent the release of radioactivity to the environment. There will be restricted access to the affected rooms until they are decontaminated. A full investigation of the incident will be conducted. The IAEA has informed the Austrian regulatory authority. The IAEA's Laboratory in Seibersdorf is located within the complex of the Austrian Research Centers Seibersdorf (ARC), about 35 km southeast of Vienna. The laboratory routinely analyses small samples of nuclear material (uranium or plutonium) as part of the IAEA's safeguards verification work. (IAEA)

Assessment of SRS radiological liquid and airborne contaminants and pathways

International Nuclear Information System (INIS)

Jannik, G.T.

1997-04-01

This report compiles and documents the radiological critical-contaminant/critical-pathway analysis performed for SRS. The analysis covers radiological releases to the atmosphere and to surface water, which are the principal media that carry contaminants off site. During routine operations at SRS, limited amounts of radionuclides are released to the environment through atmospheric and/or liquid pathways. These releases potentially result in exposure to offsite people. Though the groundwater beneath an estimated 5 to 10 percent of SRS has been contaminated by radionuclides, there is no evidence that groundwater contaminated with these constituents has migrated offsite (Arnett, 1996). Therefore, with the notable exception of radiological source terms originating from shallow surface water migration into site streams, onsite groundwater was not considered as a potential exposure pathway to offsite people

[Observation of topography and analysis of surface contamination of titanium implant after roughness treatment].

Science.gov (United States)

Cao, Hongdan; Yang, Xiaodong; Wu, Dayi; Zhang, Xingdong

2007-04-01

The roughness treatment of dental implant surface could improve the bone bonding and increase the success rate of implant, but the difference of diverse treatments is still unknown. In this study using scanning electron microscopy (SEM), energy disperse spectrometer (EDS) and the test of contact angle, we studied the microstructure, surface contamination and surface energy, and hence conducted a comparative analysis of the following surface roughness treatments: Polished Treatment (PT), Sandblasting with Alumina(SA), Sandblasting with Aluminia and Acid-etched (SAA), Sandblasting with Titanium Acid-etched (STA), Electro-erosion Treatment(ET). The result of SEM showed that the surface displayed irregularities after roughness treatments and that the surface properties of different roughness treatments had some distinctions. SAA and SA had some sharp edges and protrutions; the STA showed a regular pattern like honeycomb, but the ET sample treated by electric erosion exhibited the deeper pores of different sizes and the pores with a perforated secondary structure. The EDS indicated that the surface was contaminated after the treatment with foreign materials; the SA surface had some embedded contaminations even after acid etching. The measurement of water contact angle indicated that the morphology correlated with the surface treatments. These findings suggest that the distinction of surface structure and composition caused by different treatments may result in the disparity in biological behavior of dental implant.

Position-sensitive radiation monitoring (surface contamination monitor). Innovative technology summary report

International Nuclear Information System (INIS)

1999-06-01

The Shonka Research Associates, Inc. Position-Sensitive Radiation Monitor both detects surface radiation and prepares electronic survey map/survey report of surveyed area automatically. The electronically recorded map can be downloaded to a personal computer for review and a map/report can be generated for inclusion in work packages. Switching from beta-gamma detection to alpha detection is relatively simple and entails moving a switch position to alpha and adjusting the voltage level to an alpha detection level. No field calibration is required when switching from beta-gamma to alpha detection. The system can be used for free-release surveys because it meets the federal detection level sensitivity limits requires for surface survey instrumentation. This technology is superior to traditionally-used floor contamination monitor (FCM) and hand-held survey instrumentation because it can precisely register locations of radioactivity and accurately correlate contamination levels to specific locations. Additionally, it can collect and store continuous radiological data in database format, which can be used to produce real-time imagery as well as automated graphics of survey data. Its flexible design can accommodate a variety of detectors. The cost of the innovative technology is 13% to 57% lower than traditional methods. This technology is suited for radiological surveys of flat surfaces at US Department of Energy (DOE) nuclear facility decontamination and decommissioning (D and D) sites or similar public or commercial sites

Position-sensitive radiation monitoring (surface contamination monitor). Innovative technology summary report

Energy Technology Data Exchange (ETDEWEB)

1999-06-01

The Shonka Research Associates, Inc. Position-Sensitive Radiation Monitor both detects surface radiation and prepares electronic survey map/survey report of surveyed area automatically. The electronically recorded map can be downloaded to a personal computer for review and a map/report can be generated for inclusion in work packages. Switching from beta-gamma detection to alpha detection is relatively simple and entails moving a switch position to alpha and adjusting the voltage level to an alpha detection level. No field calibration is required when switching from beta-gamma to alpha detection. The system can be used for free-release surveys because it meets the federal detection level sensitivity limits requires for surface survey instrumentation. This technology is superior to traditionally-used floor contamination monitor (FCM) and hand-held survey instrumentation because it can precisely register locations of radioactivity and accurately correlate contamination levels to specific locations. Additionally, it can collect and store continuous radiological data in database format, which can be used to produce real-time imagery as well as automated graphics of survey data. Its flexible design can accommodate a variety of detectors. The cost of the innovative technology is 13% to 57% lower than traditional methods. This technology is suited for radiological surveys of flat surfaces at US Department of Energy (DOE) nuclear facility decontamination and decommissioning (D and D) sites or similar public or commercial sites.

Effects of modified surfaces produced at plasma-facing surface on hydrogen release behavior in the LHD

Directory of Open Access Journals (Sweden)

Y. Nobuta

2017-08-01

Full Text Available In the present study, an additional deuterium (D ion irradiation was performed against long-term samples mounted on the helical coil can and in the outer private region in the LHD during the 17th experimental campaign. Based on the release behavior of the D and hydrogen (H retained during the experimental campaign, the difference of release behavior at the top surface and in bulk of modified surfaces is discussed. Almost all samples on the helical coil can were erosion-dominant and some samples were covered with boron or carbon, while a very thick carbon films were formed in the outer private region. In the erosion-dominant area, the D desorbed at much lower temperatures compared to that of H retained during the LHD plasma operation. For the samples covered with boron, the D tended to desorb at lower temperatures compared to H. For the carbon deposition samples, the D desorbed at much higher temperatures compared to no deposition and boron-covered samples, which was very similar to that of H. The D retention capabilities at the top surface of carbon and boron films were 2–3 times higher than no deposition area. The results indicate that the retention and release behavior at the top surface of the modified layer can be different from that of bulk substrate material.

A risk-informed basis for establishing non-fixed surface contamination limits for spent fuel transportation casks

International Nuclear Information System (INIS)

Rawl, R.R.; Eckerman, K.F.; Bogard, J.S.; Cook, J.R.

2004-01-01

The current limits for non-fixed contamination on packages used to transport radioactive materials were introduced in the 1961 edition of the International Atomic Energy Agency (IAEA) transport regulations and were based on radiation protection guidance and practices in use at that time. The limits were based on exposure scenarios leading to intakes of radionuclides by inhalation and external irradiation of the hands. These considerations are collectively referred to as the Fairbairn model. Although formulated over 40 years ago, the model remains unchanged and is still the basis of current regulatory-derived limits on package non-fixed surface contamination. There can also be doses that while not resulting directly from the contamination, are strongly influenced by and attributable to transport regulatory requirements for contamination control. For example, actions necessary to comply with the current derived limits for light-water-reactor (LWR) spent nuclear fuel (SNF) casks can result in significant external doses to workers. This is due to the relatively high radiation levels around the loaded casks, where workers must function during the measurement of contamination levels and while decontaminating the cask. In order to optimize the total dose received due to compliance with cask contamination levels, it is necessary to take into account all the doses that vary as a result of the regulatory limit. Limits for non-fixed surface contamination on spent fuel casks should be established by using a model that considers and optimizes the appropriate exposure scenarios both in the workplace and in the public environment. A risk-informed approach is needed to ensure optimal use of personnel and material resources for SNF-based packaging operations. This paper is a summary of a study sponsored by the US Nuclear Regulatory Commission and performed by Oak Ridge National Laboratory that examined the dose implications for removable surface contamination limits on spent fuel

Automatic Measurement of Low Level Contamination on Concrete Surfaces

International Nuclear Information System (INIS)

Tachibana, M.; Itoh, H.; Shimada, T.; Yanagihara, S.

2002-01-01

Automatic measurement of radioactivity is necessary for considering cost effectiveness in final radiological survey of building structures in decommissioning nuclear facilities. The RAPID (radiation measuring pilot device for surface contamination) was developed to be applied to automatic measurement of low level contamination on concrete surfaces. The RAPID has a capability to measure contamination with detection limit of 0.14 Bq/cm2 for 60Co in 30 seconds of measurement time and its efficiency is evaluated to be 5 m2/h in a normal measurement option. It was confirmed that low level contamination on concrete surfaces could be surveyed by the RAPID efficiently compared with direct measurement by workers through its actual application

Controlled Contamination of Epoxy Composites with PDMS and Removal by Laser Ablation

Science.gov (United States)

Palmieri, Frank; Ledesma, Rodolfo; Cataldo, Daniel; Lin, Yi; Wohl, Christopher; Gupta, Mool; Connell, John

2016-01-01

Surface preparation is critical to the performance of adhesively bonded composites. During manufacturing, minute quantities of mold release compounds are inevitably deposited on faying surfaces and may compromise bond performance. To ensure safety, mechanical fasteners and other crack arrest features must be installed in the bondlines of primary structures, which negates some advantages of adhesively bonded construction. Laser ablation is an automated, repeatable, and scalable process with high potential for the surface preparation of metals and composites in critical applications such as primary airframe structures. In this study, laser ablation is evaluated on composite surfaces for the removal of polydimethylsiloxane (PDMS), a common mold release material. Composite panels were contaminated uniformly with PDMS film thicknesses as low as 6.0 nm as measured by variable angle spectroscopic ellipsometry. Bond performance was assessed by mechanical testing using a 250 F cure, epoxy adhesive and compared with pre-bond surface inspection results. Water contact angle, optically stimulated electron emission, and laser induced breakdown spectroscopy were used to characterize contaminated and laser ablated surfaces. The failure mode obtained from double cantilever beam tests correlated well with surface characterization data. The test results indicated that even low levels of PDMS were not completely removed by laser ablation.

Materials contamination control in the microelectronic industry

International Nuclear Information System (INIS)

Tardif, F.

1993-01-01

This paper deals with many aspects of the contamination of materials in the microelectronic industry. The contamination's control of chemicals, process gases, silicon and the survey of the ions free water's purity are treated. (TEC). 29 figs., 7 tabs

Estimation of the amount of surface contamination of a water cooled nuclear reactor by cooling water analysis

Energy Technology Data Exchange (ETDEWEB)

Nagy, G. [KFKI Atomic Energy Research Institute, P.O. Box 49, Budapest H-1525 (Hungary)]. E-mail: nagyg@sunserv.kfki.hu; Somogyi, A. [KFKI Atomic Energy Research Institute, P.O. Box 49, Budapest H-1525 (Hungary); Patek, G. [Paks Nuclear Power Plant, P.O. Box 71, Paks H-7031 (Hungary); Pinter, T. [Paks Nuclear Power Plant, P.O. Box 71, Paks H-7031 (Hungary); Schiller, R. [KFKI Atomic Energy Research Institute, P.O. Box 49, Budapest H-1525 (Hungary)

2007-06-15

Calculations, based upon on-the-spot measurements, were performed to estimate the contamination of NPP primary circuit and spent fuel storage pool solid surfaces via the composition of the cooling water in connection with a non-nuclear incident in the Paks NPP. Thirty partially burnt-up fuel element bundles were damaged during a cleaning process, an incident which resulted in the presence of fission products in the cooling water of the cleaning tank (CT) situated in a separate pool (P1). Since this medium was in contact for an extended period of time with undamaged fuel elements to be used later and also with other structural materials of the spent fuel storage pool (SP), it was imperative to assess the surface contamination of these latter ones with a particular view to the amount of fission material. In want of direct methods, one was restricted to indirect information which rested mainly on the chemical and radiochemical data of the cooling water. It was found that (i) the most important contaminants were uranium, plutonium, cesium and cerium; (ii) after the isolation of P1 and SP and an extended period of filtering the only important contaminants were uranium and plutonium; (iii) the surface contamination of the primary circuit (PC) was much lower than that of either SP or P1; (iv) some 99% of the contamination was removed from the water by the end of the filtering process.

Controlled release of phenytoin for epilepsy treatment from titania and silica based materials

International Nuclear Information System (INIS)

Lopez, Tessy; Ortiz, Emma; Meza, Doraliz; Basaldella, Elena; Bokhimi, Xim; Magana, Carlos; Sepulveda, Antonio; Rodriguez, Francisco; Ruiz, Javier

2011-01-01

Research highlights: → Template technique was used to obtain well ordered nanostructured materials: SBA-15 and titania tubes. → Phenytoin (PH), a drug used in epilepsy treatment, was loaded in these materials to used como PH release. → Loaded PH showed a good stability inside the used materials as observed by spectroscopy analysis. → The load-release PH are faster in nanostructured TiO2 tubes than in mesoporous silica matrix. → There is an inverse effect of the surface area of the structured materials on the amount of released PH. - Abstract: Template technique was used to obtain well ordered nanostructured materials: mesoporous silica and nanostructured titania tubes. This technique permits the synthesis of solids with controlled mesoporosity, where a large variety of molecules that have therapeutic activity can be hosted and further released to specific sites. In this work phenytoin (PH), a drug used in epilepsy treatment, was loaded in ordered mesoporous silica (SBA 15) and nanostructured titania tubes (TiO 2 ). The pure materials and those containing PH were characterized by X-ray diffraction, FTIR spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and N 2 adsorption-desorption at 77 K. In order to determine the loading capacity of the antiepileptic drug on these silica- and titania-based materials, the loading and release of PH was investigated using UV-vis spectroscopy. Tubular structures were found for the titania samples, for which the X-ray diffractograms showed to be formed by anatase and rutile phases. On the other hand, an amorphous phase was found in the silica sample. A highly ordered hexagonal structure of 1D cylindrical channels was also observed for this material. Loaded PH showed a good stability inside the used materials as observed by spectroscopy analysis. The adsorption and desorption of PH are faster in nanostructured TiO 2 tubes than in mesoporous silica matrix.

Cask for radioactive material and method for preventing release of neutrons from radioactive material

International Nuclear Information System (INIS)

Gaffney, M.F.; Shaffer, P.T.

1981-01-01

A cask for radioactive material, such as nuclear reactor fuel or spent nuclear reactor fuel, includes a plurality of associated walled internal compartments for containing such radioactive material, with neutron absorbing material present to absorb neutrons emitted by the radioactive material, and a plurality of thermally conductive members, such as longitudinal copper or aluminum castings, about the compartment and in thermal contact with the compartment walls and with other such thermally conductive members and having thermal contact surfaces between such members extending, preferably radially, from the compartment walls to external surfaces of the thermally conductive members, which surfaces are preferably in the form of a cylinder. The ends of the shipping cask also preferably include a neutron absorber and a conductive metal covering to dissipate heat released by decay of the radioactive material. A preferred neutron absorber utilized is boron carbide, preferably as plasma sprayed with metal powder or as particles in a matrix of phenolic polymer, and the compartment walls are preferably of stainless steel, copper or other corrosion resistant and heat conductive metal or alloy. The invention also relates to shipping casks, storage casks and other containers for radioactive materials in which a plurality of internal compartments for such material, e.g., nuclear reactor fuel rods, are joined together, preferably in modular construction with surrounding heat conductive metal members, and the modules are joined together to form a major part of a finished shipping cask, which is preferably of cylindrical shape. Also within the invention are methods of safely storing radioactive materials which emit neutrons, while dissipating the heat thereof, and of manufacturing the present shipping casks

A method for prevention of radioactive material release

International Nuclear Information System (INIS)

Uchida, Shunsuke; Sato, Chikara; Kitamura, Masao.

1975-01-01

Object: To provide a method for preventing an underwater radioactive material from being released in a simple and highly reliable manner, which can decrease an amount of radioactive materials discharged into open air from reactor water containing a large amount of radioactive materials such as a reactor core pool. Structure: Pure warm water higher in temperature than that of reactor water is poured from the top of a water surface of a water tank which stores reactor water containing radioactive materials such as radioactive iodine, and water is drawn through an outlet located downwardly of the pure warm water inlet to form a layer of pure warm water at the upper part of the water tank while preventing diffusion of the reactor water into the pure warm water by the difference in density between the reactor water and the pure warm water and downward movement of the pure warm water, thereby preventing contact of the reactor water with the atmosphere and diffusion of the radioactive material into the atmosphere. (Kamimura, M.)

Analytics of Radioactive Materials Released in the Fukushima Daiichi Nuclear Accident

Energy Technology Data Exchange (ETDEWEB)

Egarievwe, Stephen U. [Nuclear Engineering and Radiological Science Center, Alabama A and M University, Huntsville, AL (United States); Nuclear Engineering Department, University of Tennessee, Knoxville, TN (United States); Coble, Jamie B.; Miller, Laurence F. [Nuclear Engineering Department, University of Tennessee, Knoxville, TN (United States)

2015-07-01

The 2011 Fukushima Daiichi nuclear accident in Japan resulted in the release of radioactive materials into the atmosphere, the nearby sea, and the surrounding land. Following the accident, several meteorological models were used to predict the transport of the radioactive materials to other continents such as North America and Europe. Also of high importance is the dispersion of radioactive materials locally and within Japan. Based on the International Atomic Energy Agency (IAEA) Convention on Early Notification of a nuclear accident, several radiological data sets were collected on the accident by the Japanese authorities. Among the radioactive materials monitored, are I-131 and Cs-137 which form the major contributions to the contamination of drinking water. The radiation dose in the atmosphere was also measured. It is impractical to measure contamination and radiation dose in every place of interest. Therefore, modeling helps to predict contamination and radiation dose. Some modeling studies that have been reported in the literature include the simulation of transport and deposition of I-131 and Cs-137 from the accident, Cs-137 deposition and contamination of Japanese soils, and preliminary estimates of I-131 and Cs-137 discharged from the plant into the atmosphere. In this paper, we present statistical analytics of I-131 and Cs-137 with the goal of predicting gamma dose from the Fukushima Daiichi nuclear accident. The data sets used in our study were collected from the IAEA Fukushima Monitoring Database. As part of this study, we investigated several regression models to find the best algorithm for modeling the gamma dose. The modeling techniques used in our study include linear regression, principal component regression (PCR), partial least square (PLS) regression, and ridge regression. Our preliminary results on the first set of data showed that the linear regression model with one variable was the best with a root mean square error of 0.0133 μSv/h, compared

Analytics of Radioactive Materials Released in the Fukushima Daiichi Nuclear Accident

International Nuclear Information System (INIS)

Egarievwe, Stephen U.; Coble, Jamie B.; Miller, Laurence F.

2015-01-01

The 2011 Fukushima Daiichi nuclear accident in Japan resulted in the release of radioactive materials into the atmosphere, the nearby sea, and the surrounding land. Following the accident, several meteorological models were used to predict the transport of the radioactive materials to other continents such as North America and Europe. Also of high importance is the dispersion of radioactive materials locally and within Japan. Based on the International Atomic Energy Agency (IAEA) Convention on Early Notification of a nuclear accident, several radiological data sets were collected on the accident by the Japanese authorities. Among the radioactive materials monitored, are I-131 and Cs-137 which form the major contributions to the contamination of drinking water. The radiation dose in the atmosphere was also measured. It is impractical to measure contamination and radiation dose in every place of interest. Therefore, modeling helps to predict contamination and radiation dose. Some modeling studies that have been reported in the literature include the simulation of transport and deposition of I-131 and Cs-137 from the accident, Cs-137 deposition and contamination of Japanese soils, and preliminary estimates of I-131 and Cs-137 discharged from the plant into the atmosphere. In this paper, we present statistical analytics of I-131 and Cs-137 with the goal of predicting gamma dose from the Fukushima Daiichi nuclear accident. The data sets used in our study were collected from the IAEA Fukushima Monitoring Database. As part of this study, we investigated several regression models to find the best algorithm for modeling the gamma dose. The modeling techniques used in our study include linear regression, principal component regression (PCR), partial least square (PLS) regression, and ridge regression. Our preliminary results on the first set of data showed that the linear regression model with one variable was the best with a root mean square error of 0.0133 μSv/h, compared

Status on contamination monitoring in China

Energy Technology Data Exchange (ETDEWEB)

Quanlu, Gou [China Institute for Radiation Protection, Taiyuan (China)

1997-06-01

The air contaminated by radioactive materials in nuclear enterprises and radioactive workplaces and forming radioactive aerosol and the leakage of radioactive materials in operation cause internal exposure damage in workers. It is necessary and important to monitor air and surface contaminations for the health of public and workers, and for protecting environment. At present, many institutes engage in the studies on surface contamination monitoring in China, and the government has formulated the control limits of surface contamination in the Regulations of Radiation Protection. The monitors for surface contamination monitoring are almost home-made. The methods being used often are smear test and placing surface sample test. Scintillation counters, semiconductor detectors and G-M counters have been used for detecting alpha surface contamination. Plastic scintillator meters and thin wall/window G-M counters are used for beta surface contamination. Special detectors have been designed for monitoring low energy nuclides. The status of airborne contamination monitoring in China is reported. As the studies for future, the development of the surface contamination monitor for low energy beta nuclides, especially H-3, the monitoring methods for the special shapes of surfaces, the technology of decontamination and the calibration method and device for on-line radioactive aerosol continuous monitors are taken up. (K.I.)

Estimating release of polycyclic aromatic hydrocarbons from coal-tar contaminated soil at manufactured gas plant sites. Final report

International Nuclear Information System (INIS)

Lee, L.S.

1998-04-01

One of EPRI's goals regarding the environmental behavior of organic substances consists of developing information and predictive tools to estimate the release potential of polycyclic aromatic hydrocarbons (PAHs) from contaminated soils at manufactured gas (MGP) plant sites. A proper assessment of the distribution of contaminants under equilibrium conditions and the potential for mass-transfer constraints is essential in evaluating the environmental risks of contaminants in the subsurface at MGP sites and for selecting remediation options. The results of this research provide insights into estimating maximum release concentrations of PAHs from MGP soils that have been contaminated by direct contact with the tar or through years of contact with contaminated groundwater. Attention is also given to evaluating the use of water-miscible cosolvents for estimating aqueous phase concentrations, and assessing the role of mass-transfer constraints in the release of PAHs from MGP site soils

Soft electron processor for surface sterilization of food material

International Nuclear Information System (INIS)

Baba, Takashi; Kaneko, Hiromi; Taniguchi, Shuichi

2004-01-01

As frozen or chilled foods have become popular nowadays, it has become very important to provide raw materials with lower level microbial contamination to food processing companies. Consequently, the sterilization of food material is one of the major topics for food processing. Dried materials like grains, beans and spices, etc., are not typically deeply contaminated by microorganisms, which reside on the surfaces of materials, so it is very useful to take low energetic, lower than 300 keV, electrons with small penetration power (Soft-Electrons), as a sterilization method for such materials. Soft-Electrons is researched and named by Dr. Hayashi et al. This is a non-thermal method, so one can keep foods hygienic without serious deterioration. It is also a physical method, so is free from residues of chemicals in foods. Recently, Nissin-High Voltage Co., Ltd. have developed and manufactured equipment for commercial use of Soft-Electrons (Soft Electron Processor), which can process 500 kg/h of grains. This report introduces the Soft Electron Processor and shows the results of sterilization of wheat and brown rice by the equipment

Radon-induced surface contaminations in neutrinoless double beta decay and dark matter experiments

International Nuclear Information System (INIS)

Pattavina, L.

2011-01-01

In experiments looking for rare events, like neutrinoless double beta decay (DBD0ν) and dark matter search (DM), one of the main issues is to increase the experimental sensitivity through the material selection and production. The background contribution coming from the materials used for the detector realization has to be minimized. Moreover the net reduction of the background produced by the bulk part of the apparatus has raised concerns about the background contribution coming from the surfaces. Many procedures and techniques were developed during the last years in order to remove and to minimize the presence of possible contaminants on detector surfaces. To succeed in this strategy a big effort was put in defining all possible mechanisms that lead to surface contaminations, as well as specific cleaning procedures, which are able to reduce and control the surface radioactivity. The presence in air and gases of possible radioactive elements that can stick on the detector surfaces can lead to a recontamination process that will vanish all the applied cleaning procedures. Here is presented and analyzed the contribution to the background of rare events experiments like CUORE experiment (DBD0ν) and EDELWEISS experiment (DM) produced by an exposure of their detector components to a big activity of 222 Rn, radioactive daughter isotope from the 238 U chain. (author)

Satellite Contamination and Materials Outgassing Knowledge base

Science.gov (United States)

Minor, Jody L.; Kauffman, William J. (Technical Monitor)

2001-01-01

Satellite contamination continues to be a design problem that engineers must take into account when developing new satellites. To help with this issue, NASA's Space Environments and Effects (SEE) Program funded the development of the Satellite Contamination and Materials Outgassing Knowledge base. This engineering tool brings together in one location information about the outgassing properties of aerospace materials based upon ground-testing data, the effects of outgassing that has been observed during flight and measurements of the contamination environment by on-orbit instruments. The knowledge base contains information using the ASTM Standard E- 1559 and also consolidates data from missions using quartz-crystal microbalances (QCM's). The data contained in the knowledge base was shared with NASA by government agencies and industry in the US and international space agencies as well. The term 'knowledgebase' was used because so much information and capability was brought together in one comprehensive engineering design tool. It is the SEE Program's intent to continually add additional material contamination data as it becomes available - creating a dynamic tool whose value to the user is ever increasing. The SEE Program firmly believes that NASA, and ultimately the entire contamination user community, will greatly benefit from this new engineering tool and highly encourages the community to not only use the tool but add data to it as well.

A statistical model for deriving probability distributions of contamination for accidental releases

International Nuclear Information System (INIS)

ApSimon, H.M.; Davison, A.C.

1986-01-01

Results generated from a detailed long-range transport model, MESOS, simulating dispersal of a large number of hypothetical releases of radionuclides in a variety of meteorological situations over Western Europe have been used to derive a simpler statistical model, MESOSTAT. This model may be used to generate probability distributions of different levels of contamination at a receptor point 100-1000 km or so from the source (for example, across a frontier in another country) without considering individual release and dispersal scenarios. The model is embodied in a series of equations involving parameters which are determined from such factors as distance between source and receptor, nuclide decay and deposition characteristics, release duration, and geostrophic windrose at the source. Suitable geostrophic windrose data have been derived for source locations covering Western Europe. Special attention has been paid to the relatively improbable extreme values of contamination at the top end of the distribution. The MESOSTAT model and its development are described, with illustrations of its use and comparison with the original more detailed modelling techniques. (author)

Beta Autoradiography. An analytical technique to investigate radionuclides contamination on surface

International Nuclear Information System (INIS)

Ficher, P.; Goutelard, F.; Siitari-Kauppi, M.

2012-01-01

In decommissioning of old buildings and after disposal of nuclear facilities (materials, glove boxes,...), the inventory of the radioactive contamination of various building materials needs to be obtained in order to fix the working condition for dismantling. The challenge of this study was to classify different building materials of a whole research laboratory that was dedicated to research on organic molecules labeled with H-3 and C-14. The problem of waste classification is essential for safety treatment of waste and also for its cost. The analytical technique of beta autoradiography particularly well known for biological researches has been tested to investigate radionuclides contamination on surface. This technique is mainly interesting for beta and alpha emitters but also sensitive to gamma radiation. The first step of this technique is the deposit of a film on the surface of material to be analyzed. Films can be deposited on the ground or also fixed on the walls or even on the ceiling. The film is a plastic sheet covered with an emulsion containing photostimulable crystals and Eu that is activated when the film is exposed on radioactive source. The exposed films are then scanned with the Cyclone Plus equipment to get a digitized image. This image represents the radioactivity of the surface studied. The possibility to re-use the films is very important to investigate a large area. This autoradiography technique has retained our attention for its sensitivity and moreover the possibility of 2-dimensional investigation has been found as a real advantage. However it remains now as a qualitative technique and new studies must be launched to prove its quantitative potentialities. The high spatial resolution was not as important as in biological observation, and the mm resolution is totally sufficient

Evaluation of the contribution of contamination of radiotherapy room surfaces in the measure of exposure rate of radioiodine therapy patients; Avaliacao da contribuicao da contaminacao de superficies do quarto terapeutico na medida da taxa de exposicao de pacientes de radioiodoterapia

Energy Technology Data Exchange (ETDEWEB)

Campos, Rafael Ferreira

2015-07-01

The contamination of radiotherapy room surfaces is significant and the measures of patient exposure rate are held on the fourth dependencies, relevant questions are raised: the background radiation of the room stay high due to surface contamination, may interfere with the rate of patient exposure at the time of its release? The monitoring site is important to determine whether the patient will be released? The value of the deal activity and the clinical condition of the patient may increase the contamination, influencing the monitoring results? This paper aims to conduct a quantitative analysis of surface contamination of the contribution of therapeutic room at the time is monitored exposure rate from inpatient. Measurements were made regarding the hospitalization of 32 patients with different doses administered activity, age and of both genders. The measurements were performed in the therapeutic rooms at the hospital Brotherhood Santa Casa de Misericordia de Sao Paulo. Exposure rate measurements were performed at the center of the room at 1 meter of the patient on the day of its release. After his release and prior to decontamination, measurements were performed at predetermined landmarks within the therapeutic room. The results revealed that on average background radiation, high due to surface contamination contributes only 2% of the patient dose rate. It can be considered that even with influence of contamination of surfaces, this is insignificant to determine if the patient may or may not be released. This study suggests that the site in which monitoring occurs exposure rate of the patient should not be decisive for liberation thereof. (author)

Unrestricted release measurements with ambient air ionization monitors

International Nuclear Information System (INIS)

MacArthur, D.; Gunn, R.; Dockray, T.; Luff, C.

1999-01-01

Radiation monitoring systems based on the long-range alpha detection (LRAD) technique, such as the BNFL Instruments IonSens trademark, provide a single contamination measurement for an entire object rather than the more familiar individual readings for smaller surface areas. The LRAD technique relies on the ionization of ambient air molecules by alpha particles, and the subsequent detection of these ions, rather than direct detection of the alpha particles themselves. A single monitor can detect all of the ions produced over a large object and report a total contamination level for the entire surface of that object. However, both the unrestricted release limits specified in USDOE Order 5400.5 (and similar documents in other countries), and the definitions of radioactive waste categories, are stated in terms of contamination per area. Thus, conversion is required between the total effective contamination as measured by the LRAD-based detector and the allowable release limits. In addition, since the release limits were not written assuming an averaging detector system, the method chosen to average the assumed contamination over the object can have a significant impact on the effective sensitivity of the detector

Radiological decontamination, survey, and statistical release method for vehicles

International Nuclear Information System (INIS)

Goodwill, M.E.; Lively, J.W.; Morris, R.L.

1996-06-01

Earth-moving vehicles (e.g., dump trucks, belly dumps) commonly haul radiologically contaminated materials from a site being remediated to a disposal site. Traditionally, each vehicle must be surveyed before being released. The logistical difficulties of implementing the traditional approach on a large scale demand that an alternative be devised. A statistical method for assessing product quality from a continuous process was adapted to the vehicle decontamination process. This method produced a sampling scheme that automatically compensates and accommodates fluctuating batch sizes and changing conditions without the need to modify or rectify the sampling scheme in the field. Vehicles are randomly selected (sampled) upon completion of the decontamination process to be surveyed for residual radioactive surface contamination. The frequency of sampling is based on the expected number of vehicles passing through the decontamination process in a given period and the confidence level desired. This process has been successfully used for 1 year at the former uranium millsite in Monticello, Utah (a cleanup site regulated under the Comprehensive Environmental Response, Compensation, and Liability Act). The method forces improvement in the quality of the decontamination process and results in a lower likelihood that vehicles exceeding the surface contamination standards are offered for survey. Implementation of this statistical sampling method on Monticello projects has resulted in more efficient processing of vehicles through decontamination and radiological release, saved hundreds of hours of processing time, provided a high level of confidence that release limits are met, and improved the radiological cleanliness of vehicles leaving the controlled site

Treatment of contaminated waste plastics material

International Nuclear Information System (INIS)

Sims, J.; Hitchcock, J.W.

1984-01-01

Radioactive contaminated plastics material is treated by reducing it to uniform-sized debris and extruding it from a heated extruder into a sealed container in monolithic block form or as an in-fill matrix for other contaminated waste articles to create a substantially void-free sealed mass for disposal. Density adjusting fillers may be included. Extrusion may alternatively take place into a clean sealable plastics tube. (author)

Rate of Isotope Exchange Reaction Between Tritiated Water in a Gas Phase and Water on the Surface of Piping Materials

International Nuclear Information System (INIS)

Nakashio, Nobuyuki; Yamaguchi, Junya; Kobayashi, Ryusuke; Nishikawa, Masabumi

2001-01-01

The system effect of tritium arises from the interaction of tritium in the gas phase with water on the surface of piping materials. It has been reported that the system effect can be quantified by applying the serial reactor model to the piping system and that adsorption and isotope exchange reactions play the main roles in the trapping of tritium. The isotope exchange reaction that occurs when the chemical form of tritium in the gas phase is in the molecular form, i.e., HT or T 2 , has been named isotope exchange reaction 1, and that which occurs when tritium in the gas phase is in water form, i.e., HTO or T 2 O, has been named isotope exchange reaction 2.The rate of isotope exchange reaction 2 is experimentally quantified, and the rate is observed to be about one-third of the rate of adsorption. The trapping and release behavior of tritium from the piping surface due to isotope exchange reaction 2 is also discussed. It is certified that swamping of water vapor to process gas is effective to release tritium from the surface contaminated with tritium

Radioactivity decontamination of materials commonly used as surfaces in general-purpose radioisotope laboratories.

Science.gov (United States)

Leonardi, Natalia M; Tesán, Fiorella C; Zubillaga, Marcela B; Salgueiro, María J

2014-12-01

In accord with as-low-as-reasonably-achievable and good-manufacturing-practice concepts, the present study evaluated the efficiency of radioactivity decontamination of materials commonly used in laboratory surfaces and whether solvent spills on these materials affect the findings. Four materials were evaluated: stainless steel, a surface comprising one-third acrylic resin and two-thirds natural minerals, an epoxy cover, and vinyl-based multipurpose flooring. Radioactive material was eluted from a (99)Mo/(99m)Tc generator, and samples of the surfaces were control-contaminated with 37 MBq (100 μL) of this eluate. The same procedure was repeated with samples of surfaces previously treated with 4 solvents: methanol, methyl ethyl ketone, acetone, and ethanol. The wet radioactive contamination was allowed to dry and then was removed with cotton swabs soaked in soapy water. The effectiveness of decontamination was defined as the percentage of activity removed per cotton swab, and the efficacy of decontamination was defined as the total percentage of activity removed, which was obtained by summing the percentages of activity in all the swabs required to complete the decontamination. Decontamination using our protocol was most effective and most efficacious for stainless steel and multipurpose flooring. Moreover, treatment with common organic solvents seemed not to affect the decontamination of these surfaces. Decontamination of the other two materials was less efficient and was interfered with by the organic solvents; there was also great variability in the overall results obtained for these other two materials. In expanding our laboratory, it is possible for us to select those surface materials on which our decontamination protocol works best. © 2014 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Resolving Radiological Classification and Release Issues for Many DOE Solid Wastes and Salvageable Materials

International Nuclear Information System (INIS)

Hochel, R.C.

1999-01-01

The cost effective radiological classification and disposal of solid materials with potential volume contamination, in accordance with applicable U.S. Department of Energy (DOE) Orders, suffers from an inability to unambiguously distinguish among transuranic waste, low-level waste, and unconditional-release materials in a generic way allowing in-situ measurement and verification. Depending on a material''s classification, disposal costs can vary by a hundred-fold. With these large costs at risk, the issues involved in making defensible decisions are ripe for closer scrutiny. In many cases, key issues can be easily resolved by a combination of process information, some simple measurements, and calculational predictions from a computer model for radiation shielding. The proper classification and disposal of many solid wastes requires a measurement regime that is able to show compliance with a variety of institutional and regulatory contamination limits. Ultimate responsibility for this, of course, rests with radiological control or health physics organization of the individual site, but there are many measurements which can be performed by operations and generation organizations to simplify the process and virtually guarantee acceptance. Although this is not possible for all potential solid wastes, there are many that do lend themselves to such measures, particularly some of large volumes and realizable cost savings. Mostly what is needed for this to happen are a few guiding rules, measurement procedures, and cross checks for potential pitfalls. Several examples are presented here and discussed that demonstrate the possibilities, including one which was successfully applied to bulk contamination

Effect of micropatterning induced surface hydrophobicity on drug release from electrospun cellulose acetate nanofibers

Science.gov (United States)

Adepu, Shivakalyani; Gaydhane, Mrunalini K.; Kakunuri, Manohar; Sharma, Chandra S.; Khandelwal, Mudrika; Eichhorn, Stephen J.

2017-12-01

Sustained release and prevention of burst release for low half-life drugs like Diclofenac sodium is crucial to prevent drug related toxicity. Electrospun nanofibers have emerged recently as potential carrier materials for controlled and sustained drug release. Here, we present a facile method to prevent burst release by tuning the surface wettability through template assisted micropatterning of drug loaded electrospun cellulose acetate (CA) nanofibers. A known amount of drug (Diclofenac sodium) was first mixed with CA and then electrospun in the form of a nanofabric. This as-spun network was hydrophilic in nature. However, when electrospinning was carried out through non-conducting templates, viz nylon meshes with 50 and 100 μm size openings, two kinds of hydrophobic micro-patterned CA nanofabrics were produced. In vitro transdermal testing of our nanofibrous mats was carried out; these tests were able to show that it would be possible to create a patch for transdermal drug release. Further, our results show that with optimized micro-patterned dimensions, a zero order sustained drug release of up to 12 h may be achieved for the transdermal system when compared to non-patterned samples. This patterning caused a change in the surface wettability, to a hydrophobic surface, resulting in a controlled diffusion of the hydrophilic drug. Patterning assisted in controlling the initial burst release, which is a significant finding especially for low half-life drugs.

Both Phosphorus Fertilizers and Indigenous Bacteria Enhance Arsenic Release into Groundwater in Arsenic-Contaminated Aquifers.

Science.gov (United States)

Lin, Tzu-Yu; Wei, Chia-Cheng; Huang, Chi-Wei; Chang, Chun-Han; Hsu, Fu-Lan; Liao, Vivian Hsiu-Chuan

2016-03-23

Arsenic (As) is a human carcinogen, and arsenic contamination in groundwater is a worldwide public health concern. Arsenic-affected areas are found in many places but are reported mostly in agricultural farmlands, yet the interaction of fertilizers, microorganisms, and arsenic mobilization in arsenic-contaminated aquifers remains uncharacterized. This study investigates the effects of fertilizers and bacteria on the mobilization of arsenic in two arsenic-contaminated aquifers. We performed microcosm experiments using arsenic-contaminated sediments and amended with inorganic nitrogenous or phosphorus fertilizers for 1 and 4 months under aerobic and anaerobic conditions. The results show that microcosms amended with 100 mg/L phosphorus fertilizers (dipotassium phosphate), but not nitrogenous fertilizers (ammonium sulfate), significantly increase aqueous As(III) release in arsenic-contaminated sediments under anaerobic condition. We also show that concentrations of iron, manganese, potassium, sodium, calcium, and magnesium are increased in the aqueous phase and that the addition of dipotassium phosphate causes a further increase in aqueous iron, potassium, and sodium, suggesting that multiple metal elements may take part in the arsenic release process. Furthermore, microbial analysis indicates that the dominant microbial phylum is shifted from α-proteobacteria to β- and γ-proteobacteria when the As(III) is increased and phosphate is added in the aquifer. Our results provide evidence that both phosphorus fertilizers and microorganisms can mediate the release of arsenic to groundwater in arsenic-contaminated sediments under anaerobic condition. Our study suggests that agricultural activity such as the use of fertilizers and monitoring phosphate concentration in groundwater should be taken into consideration for the management of arsenic in groundwater.

Methodology for performing surveys for fixed contamination

International Nuclear Information System (INIS)

Durham, J.S.; Gardner, D.L.

1994-10-01

This report describes a methodology for performing instrument surveys for fixed contamination that can be used to support the release of material from radiological areas, including release to controlled areas and release from radiological control. The methodology, which is based on a fast scan survey and a series of statistical, fixed measurements, meets the requirements of the U.S. Department of Energy Radiological Control Manual (RadCon Manual) (DOE 1994) and DOE Order 5400.5 (DOE 1990) for surveys for fixed contamination and requires less time than a conventional scan survey. The confidence interval associated with the new methodology conforms to the draft national standard for surveys. The methodology that is presented applies only to surveys for fixed contamination. Surveys for removable contamination are not discussed, and the new methodology does not affect surveys for removable contamination

Contamination of optical surfaces in Earth orbit

Science.gov (United States)

Kinser, Donald L.; Weller, Robert A.; Mendenhall, M. H.; Wiedlocher, D. E.; Nichols, R.; Tucker, D.; Whitaker, A.

1992-01-01

Glass and glass ceramic samples exposed to the low earth orbit environment for approximately 5.5 years on the Long Duration Exposure Facility (LDEF) were found to display limited degradation in optical transmission. Commercial optical quality fused silica samples display decreases in transmission in the 200 to 400 nm wavelength region, and this degradation appears to be a consequence of surface contamination. The contamination, found only on internal surfaces of samples, was measured by medium energy backscattering spectrometry and found to be primarily carbon. Additional thin film contamination by a species with atomic mass near 64, which was present at the level of about 8 x 10 exp 14/sq. cm has not been identified. These observations are consistent with the interpretation that organic binders used in the black absorbing paint (Chem Glaze Z-306) inside the sample holding tray were concentrated in the vicinity of the samples and photolytically cracked by solar UV radiation. The resulting decomposition products were deposited on the interior sample surface and gave rise to the optical transmission loss. No detectable contamination was observed on the external or space exposed surface of the samples. No measurable damage was detected which could be attributed to the direct action of gamma or UV radiation on the glass samples. These results emphasize the need for special precautions in the preparation of spacecraft carrying precision optical components on long duration missions.

New Class of Hybrid Materials for Detection, Capture, and "On-Demand" Release of Carbon Monoxide.

Science.gov (United States)

Pitto-Barry, Anaïs; Lupan, Alexandru; Ellingford, Christopher; Attia, Amr A A; Barry, Nicolas P E

2018-04-25

Carbon monoxide (CO) is both a substance hazardous to health and a side product of a number of industrial processes, such as methanol steam reforming and large-scale oxidation reactions. The separation of CO from nitrogen (N 2 ) in industrial processes is considered to be difficult because of the similarities of their electronic structures, sizes, and physicochemical properties (e.g., boiling points). Carbon monoxide is also a major poison in fuel cells because of its adsorption onto the active sites of the catalysts. It is therefore of the utmost economic importance to discover new materials that enable effective CO capture and release under mild conditions. However, methods to specifically absorb and easily release CO in the presence of contaminants, such as water, nitrogen, carbon dioxide, and oxygen, at ambient temperature are not available. Here, we report the simple and versatile fabrication of a new class of hybrid materials that allows capture and release of carbon monoxide under mild conditions. We found that carborane-containing metal complexes encapsulated in networks made of poly(dimethylsiloxane) react with CO, even when immersed in water, leading to dramatic color and infrared signature changes. Furthermore, we found that the CO can be easily released from the materials by simply dipping the networks into an organic solvent for less than 1 min, at ambient temperature and pressure, which not only offers a straightforward recycling method, but also a new method for the "on-demand" release of carbon monoxide. We illustrated the utilization of the on-demand release of CO from the networks by carrying out a carbonylation reaction on an electron-deficient metal complex that led to the formation of the CO-adduct, with concomitant recycling of the gel. We anticipate that our sponge-like materials and scalable methodology will open up new avenues for the storage, transport, and controlled release of CO, the silent killer and a major industrial poison.

Multiple containment for LSA [low specific activity] and SCO [surface contaminated objects] wastes

International Nuclear Information System (INIS)

Burgess, M.H.

1993-09-01

Radioactive wastes are generally transported in the form of Low Specific Activity (LSA) materials or Surface Contaminated Objects (SCO). This report proposes that a method of acknowledging the beneficial effects of multiple containment for such wastes should be written into the 1996 Edition of the IAEA Transport Regulations. Experience used to assess risks from on-site movements of radioactive material in the UK can be applied to develop safety arguments justifying the alleviation of off-site transport risks. (UK)

Contamination of the cement raw material in a quarry site by seawater intrusion, Darica-Turkey

Science.gov (United States)

Camur, M. Zeki; Doyuran, Vedat

2008-02-01

The open pit mining nearby shoreline is planned to be extended into below sea level in order to use additional reserves of the cement raw material (marl). The raw material is currently contaminated by seawater intrusion below a depth of 20 m up to the distance of 90 m from shoreline. Seawater intrusion related contamination of the material used for the cement production was investigated by means of diffusion process for the future two below sea level mining scenarios covering 43 years of period. According to the results, chloride concentrations higher than the tolerable limit of a cement raw material would be present in the material about 10-25 cm inward from each discontinuity surface, controlling groundwater flow, located between 170 and 300 m landward from the shoreline at below sea level mining depths of 0-30 m. The estimations suggest that total amounts of dilution required for the contaminated raw material to reduce its concentration level to the tolerance limit with uncontaminated raw material are about 113- to 124-fold for scenario I (13 years of below sea level mining after 30 years of above sea level mining) and about 126- to 138-fold for scenario II (43 years of simultaneous above and below sea level minings).

Improvement of a device for monitoring the contamination of surfaces

International Nuclear Information System (INIS)

Barbier, Albert.

1981-01-01

The purpose of this invention is to make it possible to monitor the contamination of surfaces by a light weight portable device and enabling the alpha, beta and gamma radiation contamination to be detected. The detection probe which is connected by a single lead to the box is adapted, in each particular case, to the radiation mode emitted by the contaminated surfaces and the box is provided with a special leak-proof socket for connecting the probe and includes means for assessing the counting rate of the radiation given off, depending on the mode of the radiations emitted by the contaminated surfaces and the intensity of the count rate [fr

Dedicated new descaling method to characterize corrosion and cation release of SG tubing materials

International Nuclear Information System (INIS)

Clauzel, Maryline; Guillodo, Michael; Foucault, Marc; Engler, Nathalie; Chahma, Farah

2012-09-01

PWR steam generators (SGs), due to the huge wetted surface, are the main source of corrosion product release in the primary coolant circuit. Corrosion products may be transported throughout the whole circuit, activated in the core, and redeposited all over circuit surfaces, resulting in an increase of activity buildup. Understanding the phenomena leading to corrosion product release from SG tubing materials is of primary importance to minimize the global dose integrated by workers and to optimize the reactor shutdown duration and environment releases. Lab scale testing devices are a way to investigate cation release and propose mitigation measures. The descaling technique is based on the specific dissolution of the oxides making possible, by gravimetry, to directly evaluate the total quantity of corroded metal and the quantity of released elements. This technique allows for a statistical study as several SG coupons are exposed in one single test and is usually well-adapted to tubing materials having high or medium cation release behaviors, but has been proven too less accurate for the most recent manufactured SG tubes having low cation release rates. An optimized descaling technique has been developed to allow for the study of low-releasing SG tubing materials. Several steps of the process have been reconsidered. The electropolishing of the coupon is now performed after a careful determination of the thickness of the perturbed layer on the tube outer and/or inner surface to completely remove it so as to limit as much as possible the release of electro-polished faces which are not matter of the study. The number of coupons exposed in the autoclave has been reduced to avoid any saturation of the water primary chemistry, and two kinds of control coupons have been prepared instead of one in the former descaling method to take into account the uncertainties due to the descaling process as well as the CP possible redeposition on the coupons during exposure. Another

Reduction of surface erosion in fusion reactors

International Nuclear Information System (INIS)

Rossing, T.D.; Das, S.K.; Kaminsky, M.

1976-01-01

Some of the major processes leading to surface erosion in fusion reactors are reviewed briefly, including blistering by implanted gas, sputtering by ions, atoms, and neutrons, and vaporization by local heating. Surface erosion affects the structural integrity and limits the lifetime of reactor components exposed to plasma radiation. In addition, some of the processes leading to surface erosion also cause the release of plasma contaminants. Methods proposed to reduce surface erosion have included control of surface temperature, selection of materials with a favorable microstructure, chemical and mechanical treatment of surfaces, and employment of protective surface coatings, wall liners, and divertors. The advantages and disadvantages of some of these methods are discussed

TECHNICAL BASIS FOR EVALUATING SURFACE BARRIERS TO PROTECT GROUNDWATER FROM DEEP VADOSE ZONE CONTAMINATION

International Nuclear Information System (INIS)

Fayer, J.M.; Freedman, V.L.; Ward, A.L.; Chronister, G.B.

2010-01-01

The U.S. DOE and its predecessors released nearly 2 trillion liters (450 billion gallons) of contaminated liquid into the vadose zone at the Hanford Site. Some of the contaminants currently reside in the deeper parts of the vadose zone where they are much less accessible to characterization, monitoring, and typical remediation activities. The DOE Richland Operations Office (DOE-RL) prepared a treatability test plan in 2008 to examine remediation options for addressing contaminants in the deep vadose zone; one of the technologies identified was surface barriers (also known as engineered barriers, covers, and caps). In the typical configuration, the contaminants are located relatively close to the surface, generally within 15 m, and thus they are close to the base of the surface barrier. The proximity of the surface barrier under these conditions yielded few concerns about the effectiveness of the barrier at depth, particularly for cases in which the contaminants were in a lined facility. At Hanford, however, some unlined sites have contaminants located well below depths of 15 m. The issue raised about these sites is the degree of effectiveness of a surface barrier in isolating contaminants in the deep vadose zone. Previous studies by Hanford Site and PNNL researchers suggest that surface barriers have the potential to provide a significant degree of isolation of deep vadose zone contaminants. The studies show that the actual degree of isolation is site-specific and depends on many factors, including recharge rates, barrier size, depth of contaminants, geohydrologic properties ofthe sediments, and the geochemical interactions between the contaminants and the sediments. After the DOE-RL treatability test plan was published, Pacific Northwest National Laboratory was contracted to review the information available to support surface barrier evaluation for the deep vadose zone, identify gaps in the information and outcomes necessary to fill the data gaps, and outline

Hayabusa2 Sampler: Collection of Asteroidal Surface Material

Science.gov (United States)

Sawada, Hirotaka; Okazaki, Ryuji; Tachibana, Shogo; Sakamoto, Kanako; Takano, Yoshinori; Okamoto, Chisato; Yano, Hajime; Miura, Yayoi; Abe, Masanao; Hasegawa, Sunao; Noguchi, Takaaki

2017-07-01

Japan Aerospace Exploration Agency (JAXA) launched the asteroid exploration probe "Hayabusa2" in December 3rd, 2014, following the 1st Hayabusa mission. With technological and scientific improvements from the Hayabusa probe, we plan to visit the C-type asteroid 162137 Ryugu (1999 JU3), and to sample surface materials of the C-type asteroid that is likely to be different from the S-type asteroid Itokawa and contain more pristine materials, including organic matter and/or hydrated minerals, than S-type asteroids. We developed the Hayabusa2 sampler to collect a minimum of 100 mg of surface samples including several mm-sized particles at three surface locations without any severe terrestrial contamination. The basic configuration of the sampler design is mainly as same as the 1st Hayabusa (Yano et al. in Science, 312(5778):1350-1353, 2006), with several minor but important modifications based on lessons learned from the Hayabusa to fulfill the scientific requirements and to raise the scientific value of the returned samples.

Controlled release of phenytoin for epilepsy treatment from titania and silica based materials

Energy Technology Data Exchange (ETDEWEB)

Lopez, Tessy, E-mail: tessy3@prodigy.net.mx [Universidad Autonoma Metropolitana-Xochimilco. Departamento de Microbiologia. Calzada del Hueso 1100, Col. Villa Quietud, Coyoacan, C.P. 04960, Mexico D.F. Mexico (Mexico); Instituto Nacional de Neurologia y Neurocirugia ' MVS' . Laboratorio de Nanotecnologia. Av. Insurgentes Sur 3877, Col. La Fama, Tlalpan, 14269, Mexico, D.F. Mexico (Mexico); Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, LA 70118 (United States); Ortiz, Emma [Instituto Nacional de Neurologia y Neurocirugia ' MVS' . Laboratorio de Nanotecnologia. Av. Insurgentes Sur 3877, Col. La Fama, Tlalpan, 14269, Mexico, D.F. Mexico (Mexico); Meza, Doraliz [Universidad Autonoma Metropolitana-Iztapalapa, Departamento de Quimica, Av. San Rafael Atlixco 186, A.P. 55-534, Mexico D.F., C.P. 09340 (Mexico); Basaldella, Elena [CIC-CINDECA - Universidad Nacional de La Plata - Calle 47 No 257 - La Plata (Argentina); Bokhimi, Xim; Magana, Carlos [Instituto de fisica, UNAM. Circuito de la Investigacion s/n. C.U. Mexico D.F. 01000 (Mexico); Sepulveda, Antonio; Rodriguez, Francisco; Ruiz, Javier [Departamento de Quimica Inorganica, Universidad de Alicante. Apartado 99, E-03080 Alicante, Espana Spain (Spain)

2011-04-15

Research highlights: {yields} Template technique was used to obtain well ordered nanostructured materials: SBA-15 and titania tubes. {yields} Phenytoin (PH), a drug used in epilepsy treatment, was loaded in these materials to used como PH release. {yields} Loaded PH showed a good stability inside the used materials as observed by spectroscopy analysis. {yields} The load-release PH are faster in nanostructured TiO2 tubes than in mesoporous silica matrix. {yields} There is an inverse effect of the surface area of the structured materials on the amount of released PH. - Abstract: Template technique was used to obtain well ordered nanostructured materials: mesoporous silica and nanostructured titania tubes. This technique permits the synthesis of solids with controlled mesoporosity, where a large variety of molecules that have therapeutic activity can be hosted and further released to specific sites. In this work phenytoin (PH), a drug used in epilepsy treatment, was loaded in ordered mesoporous silica (SBA 15) and nanostructured titania tubes (TiO{sub 2}). The pure materials and those containing PH were characterized by X-ray diffraction, FTIR spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and N{sub 2} adsorption-desorption at 77 K. In order to determine the loading capacity of the antiepileptic drug on these silica- and titania-based materials, the loading and release of PH was investigated using UV-vis spectroscopy. Tubular structures were found for the titania samples, for which the X-ray diffractograms showed to be formed by anatase and rutile phases. On the other hand, an amorphous phase was found in the silica sample. A highly ordered hexagonal structure of 1D cylindrical channels was also observed for this material. Loaded PH showed a good stability inside the used materials as observed by spectroscopy analysis. The adsorption and desorption of PH are faster in nanostructured TiO{sub 2} tubes than in mesoporous silica

Tritium loading in ITER plasma-facing surfaces and its release under accident conditions

International Nuclear Information System (INIS)

Longhurst, G.R.; Anderl, R.A.; Pawelko, R.J.

1996-01-01

Plasma-facing surfaces of the International Thermonuclear Experimental Reactor (ITER) will take up tritium from the plasma. These surfaces will probably consist of matures of Be, C, and possibly W together with other impurities. Recent experimental results have suggested mechanisms, not previously considered in analyses, by which tritium and other hydrogen isotopes are retained in Be. This warrants revised modeling and estimation of the amount of tritium that will be deposited in ITER beryllium plasma-facing surfaces and the rates at which it can be released under postulated accident scenarios. In this paper we describe improvements in modeling and experiments planned at the Idaho National Engineering Laboratory (INEL) to investigate the tritium uptake and thermal release behavior for mixed plasma- facing materials. TMAP4 calculations were made using recent data to estimate first-wall tritium inventories in ITER. 16 refs., 1 fig

Task 12: Laser cleaning of contaminated painted surfaces. Semi-annual report, April 1, 1996--September 30, 1996

International Nuclear Information System (INIS)

Grisanti, A.A.; Hassett, D.J.

1997-01-01

Paint contaminated with radionuclides and other hazardous materials is common in Department of Energy (DOE) facilities. Facility decommissioning and decontamination requires the removal of contaminated paint. Paint removal technologies include laser- and abrasive-based systems. F2 Associates are utilizing a pulsed-repetition CO 2 laser that produces a 2.5-cm x 2.5-cm beam which can be scanned across a 30- x 100-cm raster and, when placed on a robot, can be designed to clean any surface that the robot can be programmed to follow. Causing little or no damage to the substrate (concrete, steel, etc.), the laser ablates the material to be removed from a given surface. Ablated material is then pulled into a filtration and collection (VAC-PAC) system to prevent the hazardous substances from entering into the atmosphere. The VAC-PAC system deposits the ablated material into waste drums which may be removed from the system without compromising the integrity of the seal, allowing a new drum to be set up for collection without leakage of the ablated material into the atmosphere

Improved explosive collection and detection with rationally assembled surface sampling materials

Energy Technology Data Exchange (ETDEWEB)

Chouyyok, Wilaiwan; Bays, J. Timothy; Gerasimenko, Aleksandr A.; Cinson, Anthony D.; Ewing, Robert G.; Atkinson, David A.; Addleman, R. Shane

2016-01-01

Sampling and detection of trace explosives is a key analytical process in modern transportation safety. In this work we have explored some of the fundamental analytical processes for collection and detection of trace level explosive on surfaces with the most widely utilized system, thermal desorption IMS. The performance of the standard muslin swipe material was compared with chemically modified fiberglass cloth. The fiberglass surface was modified to include phenyl functional groups. When compared to standard muslin, the phenyl functionalized fiberglass sampling material showed better analyte release from the sampling material as well as improved response and repeatability from multiple uses of the same swipe. The improved sample release of the functionalized fiberglass swipes resulted in a significant increase in sensitivity. Various physical and chemical properties were systematically explored to determine optimal performance. The results herein have relevance to improving the detection of other explosive compounds and potentially to a wide range of other chemical sampling and field detection challenges.

Modeling Groundwater-Surface Water Interaction and Contaminant Transport of Chlorinated Solvent Contaminated Site

Science.gov (United States)

Yimer Ebrahim, Girma; Jonoski, Andreja; van Griensven, Ann; Dujardin, Juliette; Baetelaan, Okke; Bronders, Jan

2010-05-01

Chlorinated-solvent form one of the largest groups of environmental chemicals. Their use and misuse in industry have lead to a large entry of these chemicals into the environment, resulting in widespread dissemination and oftentimes environmental contamination. Chlorinated solvent contamination of groundwater resources has been widely reported. For instance, there has been much interest in the assessment of these contaminant levels and their evolutions with time in the groundwater body below the Vilvoorde-Machelen industrial area (Belgium). The long industrial history of the area has lead to complex patterns of pollution from multiple sources and the site has been polluted to the extent that individual plumes are not definable any more. Understanding of groundwater/surface water interaction is a critical component for determining the fate of contaminant both in streams and ground water due to the fact that groundwater and surface water are in continuous dynamic interaction in the hydrologic cycle. The interaction has practical consequences in the quantity and quality of water in either system in the sense that depletion and/or contamination of one of the system will eventually affect the other one. The transition zone between a stream and its adjacent aquifer referred to as the hyporheic zone plays a critical role in governing contaminant exchange and transformation during water exchange between the two water bodies. The hyporheic zone of Zenne River ( the main receptor ) is further complicated due to the fact that the river banks are artificially trained with sheet piles along its reach extending some 12 m below the surface. This study demonstrates the use of MODFLOW, a widely used modular three-dimensional block-centred finite difference, saturated flow model for simulating the flow and direction of movement of groundwater through aquifer and stream-aquifer interaction and the use of transport model RT3D, a three-dimensional multi-species reactive transport model

Determination of Radiological, Material and Organizational Measures for Reuse of Conditionally Released Materials from Decommissioning

International Nuclear Information System (INIS)

Ondra, F.; Vasko, M.; Necas, V.

2012-01-01

An important part of nuclear installation decommissioning is conditional release of materials. The mass of conditionally released materials can significantly influence radioactive waste management and capacity of radioactive waste repository. The influence on a total decommissioning cost is also not negligible. Several scenarios for reuse of conditionally released materials were developed within CONRELMAT project. Each scenario contains preparation phase, construction phase and operation phase. For each above mentioned phase is needed to determine radiological, material, organizational and other constraints for conditionally released materials reuse to not break exposure limits for staff and public. Constraints are determined on the basis of external and internal exposure calculations in created models for selected takes in particular scenarios phases. The paper presents a developed methodology for determination of part of above mentioned constraints concerning external exposure of staff or public. Values of staff external exposure are also presented in paper to ensure that staff or public exposure does not break the limits. The methodology comprises a proposal of following constraints: radionuclide limit concentration of conditionally released materials for specific scenarios and nuclide vectors, specific deployment of conditionally released materials eventually shielding materials, staff and public during the scenario's phases, organizational measures concerning time of staff's or public's stay in the vicinity of conditionally released materials for individual performed scenarios and nuclide vectors. The paper further describes VISIPLAN 3D ALARA calculation planning software tool used for calculation of staff's and public's external exposure for individual scenarios. Several other parallel papers proposed for HND2012 are presenting selected details of the project.(author).

Development of an automatic smear sampler and a polymer film for surface radioactive contamination assay

International Nuclear Information System (INIS)

Seo, B.-K.; Lee, K.-W.; Woo, Z.-H.; Jeong, K.-S.; Oh, W.-Z.; Han, M.-J.

2004-01-01

Measurement of the surface contamination by an indirect method is subject to the various kinds of error according to the sampling person and needs much time and effort in the sampling and assay. In this research, an automatic smear sampler is developed. It improved efficiency for assay work of surface contamination level achieved periodically in a radiation controlled area. Using an automatic smear sampler developed, it is confirmed that radioactive contaminated materials are uniformly transferred to smear paper more than any sampling method by an operator. Also, Solid scintillation proximity membranes were prepared for measuring the amount of radioactive contamination in laboratories contaminated by the low energy beta-ray emitter, such as 3 H and 14 C. Polysulfone scintillation proximity membranes were prepared by impregnating Cerium Activated Yttrium Silicate (CAYS), an inorganic fluor, in a membrane structure. The inorganic fluor-impregnated membranes were applied to detect the radioactive surface contamination. The preparation of membranes was divided into two processes. A supporting polymer film was made of casting solutions consisting of polysulfone and solvent, their cast film being solidified by vacuum evaporation. CAYS-dispersed polymer solutions were cast over the first, solidified polymer films and coagulated either by evaporating solvent in the solution with non-solvent in a coagulation bath. The prepared membranes had two distinguished, but tightly attached, double layers : one is the supporting layer of dense polymer film and the other results revealed that the prepared membranes were efficient to monitor radioactive contamination with reliable counting ability. For enhancement of pick-up and measurement efficiency, the membrane was prepared with the condition of different membrane solidification. The scintillation produced by interaction with radiation and CAYS was measured with photomultiplier tube. The test results showed that the prepared

Effects of exogenous salinity (NaCl) gradient on Cd release in acidified contaminated brown soil

Science.gov (United States)

Zhang, Lina; Rong, Yong; Mao, Li; Gao, Zhiyuan; Liu, Xiaoyu; Dong, Zhicheng

2018-02-01

Taking acidified Cd contaminated brown soil in Yantai as the research object, based on different exogenous salinity (NaCl) gradient (0%, 0.3%, 0.6%, 0.9%, 1.5%, 2% and 5%), indoor simulation experiments of Cd release were carried out after field investigation. Results showed that there was a significantly positive relation (r>0.90) between Cd release concentration/amount/ratio and exogenous salt (NaCl). Besides, the more exogenous salt (NaCl) was added; maximum release concentration/amount of Cd appeared the earlier. It was found that exogenous salt (NaCl) addition could obviously promote Cd release from acidified Cd contaminated brown soil. It was believed that this could be mainly due to the cation exchange between Cd2+ and Na+, together with the dissociation and/or complexation between Cl- and Cd2+. In addition, available adsorption sites reduction by exchange base in soil causing Cd changed from solid state to soil solution was also a probable reason.

Surface reconstruction: An effective method for the growth of mismatched materials

Energy Technology Data Exchange (ETDEWEB)

Sun, Yu; Zheng, Beining; Wu, Xiaofeng; Yuan, Long; Wu, Jie; Guo, Hongping; Huang, Keke; Feng, Shouhua, E-mail: shfeng@mail.jlu.edu.cn

2016-01-01

Graphical abstract: High quality thin film of GaSb was fabricated with molecular beam epitaxy technique on the reconstructed Si(1 1 1) surface. - Highlights: • Surface reconstruction formed by different surface treatments controls the heteroepitaxial growth. • Mismatched stress can be effectively released when the mismatched material epi-film tilts out of the epitaxial interface plane to create a coincidence-site lattice. • GaSb films grown on Si(1 1 1)-(5√3 × 5√3)-Sb surface show better crystal quality and morphology for its self-assembled 2D fishbone structure. - Abstract: The crystalline quality of epitaxial films depends on the degree of lattice match between substrates and films. Here, we report a growth strategy for large mismatched epi-films to grow GaSb films on Si(1 1 1) substrates. The epitaxial strategy can be influenced by controlling the surface reconstructions of Sb-treated Si(1 1 1). The film with the best quality was grown on Si(1 1 1)-(5√3 × 5√3)-Sb surface due to the stress release and the formation of a self-assembled 2D fishbone structure. Controlled surface engineering provides an effective pathway towards the growth of the large mismatched materials.

A biocompatible hybrid material with simultaneous calcium and strontium release capability for bone tissue repair

Energy Technology Data Exchange (ETDEWEB)

Almeida, J. Carlos [CICECO — Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro (Portugal); Wacha, András [Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar Tudósok körútja 2, Budapest 1117 (Hungary); Gomes, Pedro S. [Laboratory for Bone Metabolism and Regeneration, Faculdade de Medicina Dentária, Universidade do Porto (Portugal); Alves, Luís C. [C2TN, Instituto Superior Técnico, Universidade de Lisboa, E.N.10, 2695-066 Bobadela LRS (Portugal); Fernandes, M. Helena Vaz [CICECO — Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro (Portugal); Salvado, Isabel M. Miranda, E-mail: isabelmsalvado@ua.pt [CICECO — Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro (Portugal); Fernandes, M. Helena R. [Laboratory for Bone Metabolism and Regeneration, Faculdade de Medicina Dentária, Universidade do Porto (Portugal)

2016-05-01

The increasing interest in the effect of strontium in bone tissue repair has promoted the development of bioactive materials with strontium release capability. According to literature, hybrid materials based on the system PDMS–SiO{sub 2} have been considered a plausible alternative as they present a mechanical behavior similar to the one of the human bone. The main purpose of this study was to obtain a biocompatible hybrid material with simultaneous calcium and strontium release capability. A hybrid material, in the system PDMS–SiO{sub 2}–CaO–SrO, was prepared with the incorporation of 0.05 mol of titanium per mol of SiO{sub 2}. Calcium and strontium were added using the respective acetates as sources, following a sol–gel technique previously developed by the present authors. The obtained samples were characterized by FT-IR, solid-state NMR, and SAXS, and surface roughness was analyzed by 3D optical profilometry. In vitro studies were performed by immersion of the samples in Kokubo's SBF for different periods of time, in order to determine the bioactive potential of these hybrids. Surfaces of the immersed samples were observed by SEM, EDS and PIXE, showing the formation of calcium phosphate precipitates. Supernatants were analyzed by ICP, revealing the capability of the material to simultaneously fix phosphorus ions and to release calcium and strontium, in a concentration range within the values reported as suitable for the induction of the bone tissue repair. The material demonstrated to be cytocompatible when tested with MG63 osteoblastic cells, exhibiting an inductive effect on cell proliferation and alkaline phosphatase activity. - Highlights: • A hybrid PDMS–SiO{sub 2}–CaO–SrO material was prepared with the incorporation of Ti. • Sr was released in concentrations suitable for the induction of bone tissue repair. • The material demonstrated to be cytocompatible when tested with osteoblastic cells.

Accounting for nanometer-thick adventitious carbon contamination in X-ray absorption spectra of carbon-based materials.

Science.gov (United States)

Mangolini, Filippo; McClimon, J Brandon; Rose, Franck; Carpick, Robert W

2014-12-16

Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy is a powerful technique for characterizing the composition and bonding state of nanoscale materials and the top few nanometers of bulk and thin film specimens. When coupled with imaging methods like photoemission electron microscopy, it enables chemical imaging of materials with nanometer-scale lateral spatial resolution. However, analysis of NEXAFS spectra is often performed under the assumption of structural and compositional homogeneity within the nanometer-scale depth probed by this technique. This assumption can introduce large errors when analyzing the vast majority of solid surfaces due to the presence of complex surface and near-surface structures such as oxides and contamination layers. An analytical methodology is presented for removing the contribution of these nanoscale overlayers from NEXAFS spectra of two-layered systems to provide a corrected photoabsorption spectrum of the substrate. This method relies on the subtraction of the NEXAFS spectrum of the overlayer adsorbed on a reference surface from the spectrum of the two-layer system under investigation, where the thickness of the overlayer is independently determined by X-ray photoelectron spectroscopy (XPS). This approach is applied to NEXAFS data acquired for one of the most challenging cases: air-exposed hard carbon-based materials with adventitious carbon contamination from ambient exposure. The contribution of the adventitious carbon was removed from the as-acquired spectra of ultrananocrystalline diamond (UNCD) and hydrogenated amorphous carbon (a-C:H) to determine the intrinsic photoabsorption NEXAFS spectra of these materials. The method alters the calculated fraction of sp(2)-hybridized carbon from 5 to 20% and reveals that the adventitious contamination can be described as a layer containing carbon and oxygen ([O]/[C] = 0.11 ± 0.02) with a thickness of 0.6 ± 0.2 nm and a fraction of sp(2)-bonded carbon of 0.19 ± 0.03. This

[Fabrication of a new composite scaffold material for delivering rifampicin and its sustained drug release in rats].

Science.gov (United States)

Ma, Xue-Ming; Lin, Zhen; Zhang, Jia-Wei; Sang, Chao-Hui; Qu, Dong-Bin; Jiang, Jian-Ming

2016-03-01

To fabricate a new composite scaffold material as an implant for sustained delivery of rifampicin and evaluate its performance of sustained drug release and biocompatibility. The composite scaffold material was prepared by loading poly(lactic-co-glycolic) acid (PLGA) microspheres that encapsulated rifampicin in a biphasic calcium composite material with a negative surface charge. The in vitro drug release characteristics of the microspheres and the composite scaffold material were evaluated; the in vivo drug release profile of the composite scaffold material implanted in a rat muscle pouch was evaluated using high-performance liquid chromatography. The biochemical parameters of the serum and liver histopathologies of the rats receiving the transplantation were observed to assess the biocompatibility of the composite scaffold material. The encapsulation efficiency and drug loading efficiency of microspheres were (56.05±5.33)% and (29.80±2.88)%, respectively. The cumulative drug release rate of the microspheres in vitro was (94.19±5.4)% at 28 days, as compared with the rate of (82.23±6.28)% of composite scaffold material. The drug-loaded composite scaffold material showed a good performance of in vivo drug release in rats, and the local drug concentration still reached 16.18±0.35 µg/g at 28 days after implantation. Implantation of the composite scaffold material resulted in transient and reversible liver injury, which was fully reparred at 28 days after the implantation. The composite scaffold material possesses a good sustained drug release capacity and a good biocompatibility, and can serve as an alternative approach to conventional antituberculous chemotherapy.

Physical and chemical properties of materials surfaces and interfaces

International Nuclear Information System (INIS)

Barbier, G.; Chevarier, A.; Chevarier, N.; Duclot, J.C.; Jaffrezic, C.; Leblond, E.; Millard-Pinard, N.; Marest, G.; Moncoffre, N.; Plantier, A.; Somatri, R.

1998-01-01

These studies are based on the combination of ion implantation and nuclear analysis techniques. They are performed on metals, semiconductors and ceramic materials in collaboration with laboratories involved in the elaboration of these materials. The different studies are the following: 1. surface treatment of aluminium using ion beam techniques; 2. hydrogen release in new plasma facing materials in Tokamak devices; 3. development of ion beam analysis methods to determine elementary depth profiles in thin films used in micro electronics; 4. Moessbauer studies of oxides prepared by laser ablation and ion implantation. (authors)

Bulk Building Material Characterization and Decontamination Using a Concrete Floor and Wall Contamination Profiling Technology

International Nuclear Information System (INIS)

Aggarwal, S.; Charters, G.; Blauvelt, D.

2002-01-01

The concrete profiling technology, RadPro(trademark) has four major components: a drill with a specialized cutting and sampling head, drill bits, a sample collection unit and a vacuum pump. The equipment in conjunction with portable radiometric instrumentation produces a profile of radiological or chemical contamination through the material being studied. The drill head is used under hammer action to penetrate hard surfaces. This causes the bulk material to be pulverized as the drill travels through the radioactive media efficiently transmitting to the sampling unit a representative sample of powdered bulk material. The profiling equipment is designed to sequentially collect all material from the hole. The bulk material samples are continuously retrieved by use of a specially designed vacuumed sample retrieval unit that prevents cross contamination of the clean retrieved samples. No circulation medium is required with this profiling process; therefore, the only by-product from drilling is the sample. The data quality, quantity, and representativeness may be used to produce an activity profile from the hot spot surface into the bulk building material. The activity data obtained during the profiling process is reduced and transferred to building drawings as part of a detailed report of the radiological problem. This activity profile may then be expanded to ultimately characterize the facility and expedite waste segregation and facility closure at a reduced cost and risk

Impact of physicochemical properties of porous silica materials conjugated with dexamethasone via pH-responsive hydrazone bond on drug loading and release behavior

Science.gov (United States)

Numpilai, Thanapha; Witoon, Thongthai; Chareonpanich, Metta; Limtrakul, Jumras

2017-02-01

The conjugation of dexamethasone (DEX) onto modified-porous silica materials via a pH-responsive hydrazone bond has been reported to be highly efficient method to specifically deliver the DEX to diseased sites. However, the influence of physicochemical properties of porous silica materials has not yet been fully understood. In this paper, the impact of pore sizes, particle sizes and silanol contents on surface functionalization, drug loading and release behavior of porous silica materials conjugated with dexamethasone via pH-responsive hydrazone bond was investigated. The grafting density was found to relate to the number of silanol groups on the surface of porous silica materials. The particle size and macropores of the porous silica materials played an vital role on the drug loading and release behavior. Although the porous silica materials with larger particle sizes possessed a lower grafting density, a larger amount of drug loading could be achieved. Moreover, the porous silica materials with larger particle sizes showed a slower release rate of DEX due to a longer distance for cleaved DEX diffusion out of pores. DEX release rate exhibited pH-dependent, sustained release. At pH 4.5, the amount of DEX release within 10 days could be controlled in the range of 12.74-36.41%, depending on the host material. Meanwhile, less than 1.5% of DEX was released from each of type of the porous silica materials at pH 7.4. The results of silica dissolution suggested that the degradation of silica matrix did not significantly affect the release rate of DEX. In addition, the kinetic modeling studies revealed that the DEX releases followed Korsmeyer-Peppas model with a release exponent (n) ranged from 0.3 to 0.47, indicating a diffusion-controlled release mechanism.

Optimization in the nuclear fuel cycle II: Surface contamination

International Nuclear Information System (INIS)

Pereira, W.S.; Silva, A.X.; Lopes, J.M.; Carmo, A.S.; Fernandes, T.S.; Mello, C.R.; Kelecom, A.

2017-01-01

Optimization is one of the bases of radioprotection and aims to move doses away from the dose limit that is the borderline of acceptable radiological risk. This work aims to use the monitoring of surface contamination as a tool of the optimization process. 53 surface contamination points were analyzed at a nuclear fuel cycle facility. Three sampling points were identified with monthly mean values of contamination higher than 1 Bq ∙ cm -2 , points 28, 42 and 47. These points were indicated for the beginning of the optimization process

Hanford Tanks 241-C-203 and 241-C-204: Residual Waste Contaminant Release Model and Supporting Data

Energy Technology Data Exchange (ETDEWEB)

Deutsch, William J.; Krupka, Kenneth M.; Lindberg, Michael J.; Cantrell, Kirk J.; Brown, Christopher F.; Schaef, Herbert T.

2004-10-28

This report describes the development of release models for key contaminants that are present in residual sludge remaining after closure of Hanford Tanks 241-C-203 (C-203) and 241-C-204 (C-204). The release models were developed from data generated by laboratory characterization and testing of samples from these two tanks. Key results from this work are (1) future releases from the tanks of the primary contaminants of concern (99Tc and 238U) can be represented by relatively simple solubility relationships between infiltrating water and solid phases containing the contaminants; and (2) high percentages of technetium-99 in the sludges (20 wt% in C-203 and 75 wt% in C-204) are not readily water leachable, and, in fact, are very recalcitrant. This is similar to results found in related studies of sludges from Tank AY-102. These release models are being developed to support the tank closure risk assessments performed by CH2M HILL Hanford Group, Inc., for the U.S. Department of Energy.

Hanford Tanks 241-C-203 and 241-C-204: Residual Waste Contaminant Release Model and Supporting Data

International Nuclear Information System (INIS)

Deutsch, William J.; Krupka, Kenneth M.; Lindberg, Michael J.; Cantrell, Kirk J.; Brown, Christopher F.; Schaef, Herbert T.

2004-01-01

This report describes the development of release models for key contaminants that are present in residual sludge remaining after closure of Hanford Tanks 241-C-203 (C-203) and 241-C-204 (C-204). The release models were developed from data generated by laboratory characterization and testing of samples from these two tanks. Key results from this work are (1) future releases from the tanks of the primary contaminants of concern (99Tc and 238U) can be represented by relatively simple solubility relationships between infiltrating water and solid phases containing the contaminants; and (2) high percentages of technetium-99 in the sludges (20 wt% in C-203 and 75 wt% in C-204) are not readily water leachable, and, in fact, are very recalcitrant. This is similar to results found in related studies of sludges from Tank AY-102. These release models are being developed to support the tank closure risk assessments performed by CH2M HILL Hanford Group, Inc., for the U.S. Department of Energy

Electrolyze radioactive contamination away

International Nuclear Information System (INIS)

Wedman, D.E.; Martinez, H.E.; Nelson, T.O.

1996-01-01

The Los Alamos National Laboratory Plutonium Facility is using electrolysis to clean the surfaces of hazardous materials. In the past, contaminated metals were cleaned with concentrated acids. Although these treatments make the surfaces safer, they produce other radioactive and toxic wastes in turn. Anodic current passes through a piece of stainless steel submersed in a sodium nitrate solution, and steel dissolves at the surfaces. Surface contamination strips away along with the surface layers. The authors are using this electrolysis approach to remove plutonium and americium from stainless steel and uranium. Unlike acid washing processes, electrolytic decontamination can be accomplished quickly. Little waste is generated regardless of how much material has to be removed from the surface. Material removal is proportional to the applied current, which gives the operator control over the rate and extent of decontamination

Calibration of alpha surface contamination monitor

International Nuclear Information System (INIS)

Freitas, I.S.M. de; Goncalez, O.L.

1990-01-01

In this work, the results, as well as the methodology, of the calibration of an alpha surface contamination monitor are presented. The calibration factors are obtained by least-squares fitting with effective variance. (author)

[Effect of saliva contamination on microleakage around class-5 cavities restored with three different types of adhesive materials].

Science.gov (United States)

Iovan, Gianina; Stoleriu, Simona; Andrian, S; Dia, V; Căruntu, Irina Draga

2004-01-01

The recent improvement of adhesive materials should decrease the risk related to saliva contamination. The aim of this study was to evaluate the effect of saliva contamination on the microleakage within class V cavities restored with three different types of materials: conventional glass ionomer cement, composite resin and compomer. 30 human extracted teeth were randomly divided in 3 equal groups. In each group, class V cavities were prepared on both facial and lingual surfaces (but joint for glass ionomer cement and bevelled incisal margin for composite resin and compomer). The lingual cavities were contaminated with saliva prior to restoration, while the facial cavities were not contaminated, serving as control. After water storage for 24 hours, teeth were immersed in 1% methylene blue solution for 24 hours. The axial sections were viewed under an optical microscope and the extent of dye penetration along cervical, axial and incisal margins was measured in millimetres. Statistic analysis showed that under salivary contamination, microleakage increased along the cervical margin of restoration for all three tested materials. Saliva contamination resulted in microleakage within the axial wall of the cavity only for the conventional glass ionomer cement. These data indicate that composite resin and compomer used together with new adhesives seem to be less sensitive to saliva contamination compared to conventional materials. However, under saliva contamination, cervical microleakage cannot be completely prevented and proper isolation should still be mandatory.

Comparing Titanium Release from Ceramic Tiles using a waste material characterization test - Influence of Calcium and Organic Matter concentrations

DEFF Research Database (Denmark)

Heggelund, Laura Roverskov; Hansen, Steffen Foss; Astrup, Thomas Fruergaard

2015-01-01

Nanomaterials are beneficial in the building industry to enhance or add certain features to commonly used materials. One example is the use of nano-titanium dioxide in the surface coating of ceramic tiles, to make the tiles surface self-cleaning. At the end of life stage, ceramic tiles might...... to assess if nano-titanium dioxide coated ceramic tiles are suitable for depositing in a landfill or not. Specifically, we used compliance batch test method, which is a simple test evaluating the release from a solid material to an aqueous media during 24 hrs. If nano-Ti particles are released from solid...... immediately after the 24 hrs. test using single particle ICPMS and Transmission Electron Microscopy imaging. The preliminary results suggest that nanoparticulate titanium is released from both tiles – with and without nano-titanium dioxide coating. The size distributions of the released particles are similar...

Decontamination of radioactively contaminated surfaces - Method for testing and assessing the ease of decontamination (International Standard Publication ISO 8690:1988)

International Nuclear Information System (INIS)

Stefanik, J.

2001-01-01

The specifications laid down in this International Standard apply to the testing of surfaces which may become contaminated by radioactive materials. Decontaminability data obtained using this test method are not applicable to technical systems where layers of contaminating materials are formed as a result of long-term application of higher temperatures and pressures (for example primary circuits of nuclear reactors). The purpose of the test is to assess the ease of decontamination of surfaces under laboratory conditions. In practical applications, it may be important to consider other qualities, such as chemical, mechanical and radiation resistance and long-term stability in the selection of the materials to be used. It should be recognized that further decontamination tests under simulated service conditions may be needed

Arsenic biotransformation and release by bacteria indigenous to arsenic contaminated groundwater.

Science.gov (United States)

Paul, Dhiraj; Kazy, Sufia K; Banerjee, Tirtha Das; Gupta, Ashok K; Pal, Taraknath; Sar, Pinaki

2015-01-01

Arsenic (As) biotransformation and release by indigenous bacteria from As rich groundwater was investigated. Metabolic landscape of 173 bacterial isolates indicated broad catabolic repertoire including abundance of As(5+) reductase activity and abilities in utilizing wide ranges of organic and inorganic respiratory substrates. Abundance of As homeostasis genes and utilization of hydrocarbon as carbon/electron donor and As(5+) as electron acceptor were noted within the isolates. Sediment microcosm study (for 300 days) showed a pivotal role of metal reducing facultative anaerobic bacteria in toxic As(3+) release in aqueous phase. Inhabitant bacteria catalyze As transformation and facilitate its release through a cascade of reactions including mineral bioweathering and As(5+) and/or Fe(3+) reduction activities. Compared to anaerobic incubation with As(5+) reducing strains, oxic state and/or incubation with As(3+) oxidizing bacteria resulted in reduced As release, thus indicating a strong role of such condition or biocatalytic mechanism in controlling in situ As contamination. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cleaning, disinfection and sterilization of surface prion contamination.

Science.gov (United States)

McDonnell, G; Dehen, C; Perrin, A; Thomas, V; Igel-Egalon, A; Burke, P A; Deslys, J P; Comoy, E

2013-12-01

Prion contamination is a risk during device reprocessing, being difficult to remove and inactivate. Little is known of the combined effects of cleaning, disinfection and sterilization during a typical reprocessing cycle in clinical practice. To investigate the combination of cleaning, disinfection and/or sterilization on reducing the risk of surface prion contamination. In vivo test methods were used to study the impact of cleaning alone and cleaning combined with thermal disinfection and high- or low-temperature sterilization processes. A standardized test method, based on contamination of stainless steel wires with high titres of scrapie-infected brain homogenates, was used to determine infectivity reduction. Traditional chemical methods of surface decontamination against prions were confirmed to be effective, but extended steam sterilization was more variable. Steam sterilization alone reduced the risk of prion contamination under normal or extended exposure conditions, but did show significant variation. Thermal disinfection had no impact in these studies. Cleaning with certain defined formulations in combination with steam sterilization can be an effective prion decontamination process, in particular with alkaline formulations. Low-temperature, gaseous hydrogen peroxide sterilization was also confirmed to reduce infectivity in the presence and absence of cleaning. Prion decontamination is affected by the full reprocessing cycle used on contaminated surfaces. The correct use of defined cleaning, disinfection and sterilization methods as tested in this report in the scrapie infectivity assay can provide a standard precaution against prion contamination. Copyright © 2013 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Corrective Action Investigation Plan for Corrective Action Unit 166: Storage Yards and Contaminated Materials, Nevada Test Site, Nevada

International Nuclear Information System (INIS)

David Strand

2006-01-01

Corrective Action Unit 166 is located in Areas 2, 3, 5, and 18 of the Nevada Test Site, which is 65 miles northwest of Las Vegas, Nevada. Corrective Action Unit (CAU) 166 is comprised of the seven Corrective Action Sites (CASs) listed below: (1) 02-42-01, Cond. Release Storage Yd - North; (2) 02-42-02, Cond. Release Storage Yd - South; (3) 02-99-10, D-38 Storage Area; (4) 03-42-01, Conditional Release Storage Yard; (5) 05-19-02, Contaminated Soil and Drum; (6) 18-01-01, Aboveground Storage Tank; and (7) 18-99-03, Wax Piles/Oil Stain. These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives. Additional information will be obtained by conducting a corrective action investigation (CAI) before evaluating corrective action alternatives and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable corrective action alternatives that will be presented in the Corrective Action Decision Document. The sites will be investigated based on the data quality objectives (DQOs) developed on February 28, 2006, by representatives of the Nevada Division of Environmental Protection; U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office; Stoller-Navarro Joint Venture; and Bechtel Nevada. The DQO process was used to identify and define the type, amount, and quality of data needed to develop and evaluate appropriate corrective actions for CAU 166. Appendix A provides a detailed discussion of the DQO methodology and the DQOs specific to each CAS. The scope of the CAI for CAU 166 includes the following activities: (1) Move surface debris and/or materials, as needed, to facilitate sampling. (2) Conduct radiological surveys. (3) Perform field screening. (4) Collect and submit environmental samples for laboratory analysis to determine if

Resolving Radiological Classification and Release Issues for Many DOE Solid Wastes and Salvageable Materials

Energy Technology Data Exchange (ETDEWEB)

Hochel, R.C.

1999-11-19

The cost effective radiological classification and disposal of solid materials with potential volume contamination, in accordance with applicable U.S. Department of Energy (DOE) Orders, suffers from an inability to unambiguously distinguish among transuranic waste, low-level waste, and unconditional-release materials in a generic way allowing in-situ measurement and verification. Depending on a material''s classification, disposal costs can vary by a hundred-fold. With these large costs at risk, the issues involved in making defensible decisions are ripe for closer scrutiny. In many cases, key issues can be easily resolved by a combination of process information, some simple measurements, and calculational predictions from a computer model for radiation shielding. The proper classification and disposal of many solid wastes requires a measurement regime that is able to show compliance with a variety of institutional and regulatory contamination limits. Ultimate responsibility for this, of course, rests with radiological control or health physics organization of the individual site, but there are many measurements which can be performed by operations and generation organizations to simplify the process and virtually guarantee acceptance. Although this is not possible for all potential solid wastes, there are many that do lend themselves to such measures, particularly some of large volumes and realizable cost savings. Mostly what is needed for this to happen are a few guiding rules, measurement procedures, and cross checks for potential pitfalls. Several examples are presented here and discussed that demonstrate the possibilities, including one which was successfully applied to bulk contamination.

SUDOQU, a new dose-assessment methodology for radiological surface contamination.

Science.gov (United States)

van Dillen, Teun; van Dijk, Arjan

2018-06-12

A new methodology has been developed for the assessment of the annual effective dose resulting from removable and fixed radiological surface contamination. It is entitled SUDOQU (SUrface DOse QUantification) and it can for instance be used to derive criteria for surface contamination related to the import of non-food consumer goods, containers and conveyances, e.g., limiting values and operational screening levels. SUDOQU imposes mass (activity)-balance equations based on radioactive decay, removal and deposition processes in indoor and outdoor environments. This leads to time-dependent contamination levels that may be of particular importance in exposure scenarios dealing with one or a few contaminated items only (usually public exposure scenarios, therefore referred to as the 'consumer' model). Exposure scenarios with a continuous flow of freshly contaminated goods also fall within the scope of the methodology (typically occupational exposure scenarios, thus referred to as the 'worker model'). In this paper we describe SUDOQU, its applications, and its current limitations. First, we delineate the contamination issue, present the assumptions and explain the concepts. We describe the relevant removal, transfer, and deposition processes, and derive equations for the time evolution of the radiological surface-, air- and skin-contamination levels. These are then input for the subsequent evaluation of the annual effective dose with possible contributions from external gamma radiation, inhalation, secondary ingestion (indirect, from hand to mouth), skin contamination, direct ingestion and skin-contact exposure. The limiting effective surface dose is introduced for issues involving the conservatism of dose calculations. SUDOQU can be used by radiation-protection scientists/experts and policy makers in the field of e.g. emergency preparedness, trade and transport, exemption and clearance, waste management, and nuclear facilities. Several practical examples are worked

Nuclear, biological and chemical contamination survivability of Army material

International Nuclear Information System (INIS)

Feeney, J.J.

1987-01-01

Army Regulation (AR) 70-71, Nuclear, Biological and Chemical (NBC) Contamination Survivability of Army Material, published during 1984, establishes Army policy and procedures for the development and acquisition of material to ensure its survivablility and sustainability on the NBC-contaminated battlefield. This regulation defines NBC contamination as a term that includes both the individual and collective effects of residual radiological, biological, and chemical contamination. AR 70-71 applies to all mission-essential equipment within the Army. NBC contamination survivability is the capability of a system and its crew to withstand an NBC-contaminated environment, including decontamination, without losing the ability to accomplish the assigned mission. Characteristics of NBC contamination survivability are decontaminability, hardness, and compatability. These characteristics are engineering design criteria which are intended for use only in a developmental setting. To comply with AR 70-71, each mission-essential item must address all three criteria. The Department of Defense (DOD) has published a draft instruction addressing acquisition of NBC contamination survivable systems. This instruction will apply throughout DOD to those programs, systems and subsystems designated by the Secretary of Defense as major systems acquisition programs and to those non-major systems that have potential impact on critical functions

Contaminated fluid filtration plant using pneumatically renewable granulated material

International Nuclear Information System (INIS)

Lucas, J.-C.; Messirejean, Pierre.

1980-01-01

This invention concerns a plant for the filtration of a contaminated fluid flow using a granulated material capable of absorbing or adsorbing the contaminants. This plant includes a filtration box within which there is at least one appreciably vertical filtering bed filled with the material and crossed by the fluid flow, loading and discharge compartments respectively located at the top and bottom of the box, each in communication with the filtering bed and an air-actuated transfer system for loading and discharging this bed through these compartments. Facilities of this kind are used mainly in the nuclear and chemical engineering industries to rid their waste of radio-iodines, generally constituted by elementary iodine and methyl iodide, or of toxic gases that contaminate them. The granulated material, whose job it is to trap these contaminants by adsorption or absorption, is generally composed of active carbon or zeolites whose utilisation time is limited [fr

Removal of contaminants from equipment and debris and waste minimization using TechXtract{reg_sign} technology

Energy Technology Data Exchange (ETDEWEB)

Bonem, M.W. [EET, Inc., Bellaire, TX (United States)

1997-10-01

Under this Program Research and Development Agreement (PRDA), EET, Inc., is extending its proprietary TechXtract{reg_sign} chemical decontamination technology into an effective, economical, integrated contaminant removal system. This integrated system will consist of a series of decontamination baths using the TechXtract{reg_sign} chemical formulas, followed by a waste treatment process that will remove the contaminants from the spent chemicals. Sufficient decontamination will result so that materials can be released without restriction after they have been treated, even those materials that have traditionally been considered to be {open_quotes}undecontaminable.{close_quotes} The secondary liquid waste will then be treated to separate any hazardous and radioactive contaminants, so that the spent chemicals and wastewater can be discharged through conventional, permitted outlets. The TechXtract{reg_sign} technology is a unique process that chemically extracts hazardous contaminants from the surface and substrate of concrete, steel, and other solid materials. This technology has been used successfully to remove contaminants as varied as PCBs, radionuclides, heavy metals, and hazardous organics. The process` advantage over other alternatives is its effectiveness in safe and consistent extraction of subsurface contamination. TechXtract{reg_sign} is a proprietary process developed, owned, and provided by EET, Inc. The objective of the PRDA is to demonstrate on a full-scale basis an economical system for decontaminating equipment and debris, with further treatment of secondary waste streams to minimize waste volumes. Contaminants will be removed from the contaminated items to levels where they can be released for unrestricted use. The entire system will be designed with maximum flexibility and automation in mind.

Removal of contaminants from equipment and debris and waste minimization using TechXtract reg-sign technology

International Nuclear Information System (INIS)

Bonem, M.W.

1997-01-01

Under this Program Research and Development Agreement (PRDA), EET, Inc., is extending its proprietary TechXtract reg-sign chemical decontamination technology into an effective, economical, integrated contaminant removal system. This integrated system will consist of a series of decontamination baths using the TechXtract reg-sign chemical formulas, followed by a waste treatment process that will remove the contaminants from the spent chemicals. Sufficient decontamination will result so that materials can be released without restriction after they have been treated, even those materials that have traditionally been considered to be open-quotes undecontaminable.close quotes The secondary liquid waste will then be treated to separate any hazardous and radioactive contaminants, so that the spent chemicals and wastewater can be discharged through conventional, permitted outlets. The TechXtract reg-sign technology is a unique process that chemically extracts hazardous contaminants from the surface and substrate of concrete, steel, and other solid materials. This technology has been used successfully to remove contaminants as varied as PCBs, radionuclides, heavy metals, and hazardous organics. The process' advantage over other alternatives is its effectiveness in safe and consistent extraction of subsurface contamination. TechXtract reg-sign is a proprietary process developed, owned, and provided by EET, Inc. The objective of the PRDA is to demonstrate on a full-scale basis an economical system for decontaminating equipment and debris, with further treatment of secondary waste streams to minimize waste volumes. Contaminants will be removed from the contaminated items to levels where they can be released for unrestricted use. The entire system will be designed with maximum flexibility and automation in mind

RCT: 2.05 Contamination Control, Course #8770

Energy Technology Data Exchange (ETDEWEB)

Hillmer, Kurt T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-05-23

This report focuses on the detection and control of radioactive contamination, which are an integral part of an aggressive ALARA program and provide an indication of the effectiveness of engineering controls and proper work practices in preventing the release of radioactive material. Radioactive contamination, if undetected or not properly controlled, can be spread and contaminate areas, equipment, personnel, and the environment.

Method of melting and decontaminating radioactive contaminated aluminum material

International Nuclear Information System (INIS)

Uda, Tatsuhiko; Miura, Noboru; Kawasaki, Katsuo; Iba, Hajime.

1986-01-01

Purpose: To improve the decontaminating efficiency upon melting decontamination of radioactive-contaminated aluminum materials. Method: This invention concerns an improvement for the method of melting decontamination by adding slug agent composed of organic compound to contaminated aluminum material and extracting the radioactive materials into the slug thereby decontaminating the aluminum material. Specifically metals effective for reducing the active amount of aluminum are added such that the content is greater than a predetermined value in the heat melting process. The metal comprises Mg, Cu or a mixture thereof and the content is more than 4 % including those previously contained in the aluminum material. (Ikeda, J.)

A controlled release of ibuprofen by systematically tailoring the morphology of mesoporous silica materials

International Nuclear Information System (INIS)

Qu Fengyu; Zhu Guangshan; Lin Huiming; Zhang Weiwei; Sun Jinyu; Li Shougui; Qiu Shilun

2006-01-01

A series of mesoporous silica materials with similar pore sizes, different morphologies and variable pore geometries were prepared systematically. In order to control drug release, ibuprofen was employed as a model drug and the influence of morphology and pore geometry of mesoporous silica on drug release profiles was extensively studied. The mesoporous silica and drug-loaded samples were characterized by X-ray diffraction, Fourier transform IR spectroscopy, N 2 adsorption and desorption, scanning electron microscopy, and transmission electron microscopy. It was found that the drug-loading amount was directly correlated to the Brunauer-Emmett-Teller surface area, pore geometry, and pore volume; while the drug release profiles could be controlled by tailoring the morphologies of mesoporous silica carriers. - Graphical abstract: The release of ibuprofen is controlled by tailoring the morphologies of mesoporous silica. The mesoporous silica and drug-loaded samples are characterized by powder X-ray diffraction, Fourier transform IR spectroscopy, N 2 adsorption and desorption, scanning electron microscopy, and transmission electron microscopy. The drug-loading amount is directly correlated to the Brunauer-Emmett-Teller surface area, pore geometry, and pore volume; while the drug release profiles can be controlled by tailoring the morphologies of mesoporous silica carriers

Remediation of a radioactively contaminated soil using a mobile soil-washing system

International Nuclear Information System (INIS)

Grant, D.C.; Lahoda, E.J.; Dietrich, A.J.; Weigle, D.H.; Keegan, C.P.; Sachse, J.D.

1993-01-01

In order to obtain free-release of a former uranium mining site in Texas, it was required that the surface soil meet specific radiological guidelines. The soil has been contaminated with uranium and radium as a result of the spillage of well-drilling material, process solutions, and ion exchange resins during mining. To meet the required guidelines, the contaminated soil had to be either removed and disposed of off-site or remediated. For economic and long-term liability reasons, remediation of the soil by soil washing was performed. The remediation of this site utilizing the Scientific Ecology Group's soil washing system is discussed in this paper

Surface displacements and energy release rates for constant stress drop slip zones in joined elastic quarter spaces

Science.gov (United States)

Rodgers, Michael J.; Wen, Shengmin; Keer, Leon M.

2000-08-01

A three-dimensional quasi-static model of faulting in an elastic half-space with a horizontal change of material properties (i.e., joined elastic quarter spaces) is considered. A boundary element method is used with a stress drop slip zone approach so that the fault surface relative displacements as well as the free surface displacements are approximated in elements over their respective domains. Stress intensity factors and free surface displacements are calculated for a variety of cases to show the phenomenological behavior of faulting in such a medium. These calculations showed that the behavior could be distinguished from a uniform half-space. Slip in a stiffer material increases, while slip in a softer material decreases the energy release rate and the free surface displacements. Also, the 1989 Kalapana earthquake was located on the basis of a series of forward searches using this method and leveling data. The located depth is 8 km, which is the closer to the seismically inferred depth than that determined from other models. Finally, the energy release rate, which can be used as a fracture criterion for fracture at this depth, is calculated to be 11.1×106 J m-2.

A consideration on internal dose evaluation and intervention based on a surface contamination concept

International Nuclear Information System (INIS)

Yasuda, H.

1997-01-01

Long-term radiation doses received by the inhabitants after the Chernobyl accident have been evaluated according to the surface contamination levels on the ground surface. The health effects have also been discussed by comparison between the surface-contaminated area and the uncontaminated control area. Selected protective measures were carried out in accordance with the contamination level of surface soil. These have been based on the 'surface contamination concept' which assumes that the radiation risk to inhabitants is proportional to the level of ground-surface contamination. The observations collected in regions around Chernobyl, however, show that the internal radiation doses to the inhabitants poorly correlate with the surface contamination level. This fact poses a question on the suitability of dose evaluations and interventions based on this concept

Sorbent materials for rapid remediation of wash water during radiological event relief

Energy Technology Data Exchange (ETDEWEB)

Jolin, William C.; Kaminski, Michael

2016-11-01

Procedures for removing harmful radiation from interior and exterior surfaces of homes and businesses after a nuclear or radiological disaster may generate large volumes of radiologically contaminated waste water. Rather than releasing this waste water to potentially contaminate surrounding areas, it is preferable to treat it onsite. Retention barrels are a viable option because of their simplicity in preparation and availability of possible sorbent materials. This study investigated the use of aluminosilicate clay minerals as sorbent materials to retain 137Cs, 85Sr, and 152Eu. Vermiculite strongly retained 137Cs, though other radionuclides displayed diminished affinity for the surface. Montmorillonite exhibited increased affinity to sorb 85Sr and 152Eu in the presence of higher concentrations of 137Cs. To simulate flow within retention barrels, vermiculite was mixed with sand and used in small-scale column experiments. The GoldSim contaminate fate module was used to model breakthrough and assess the feasibility of using clay minerals as sorbent materials in retention barrels. The modeled radionuclide breakthrough profiles suggest that vermiculite-sand and montmorillonite-sand filled barrels could be used for treatment of contaminated water generated from field operations.

Control of everyday contamination problems in a hot cell laboratory

International Nuclear Information System (INIS)

Buch, R.

1983-01-01

For handling unsealed radioactive materials, contamination monitoring and the application of appropriate methods for the prevention of contamination are essential measures to achieve radiation protection safety at the working place and during operation. It is essential to know which are the contamination sources and which circumstances may lead to contamination release and diffusion. Depending on the kind of contamination and the extent of the resulting radiation exposure, suitable easy-to-use measuring equipment is necessary. The lecture shows how contamination release can be limited or prevented, and detected in due time by the use of appropriate measuring instruments, so that contaminations and the ways of decontaminating do not necessarily cause increased dose rates. (orig.) [de

Scenarios and methods that induce protruding or released CNTs after degradation of nanocomposite materials.

Science.gov (United States)

Hirth, Sabine; Cena, Lorenzo; Cox, Gerhard; Tomović, Zeljko; Peters, Thomas; Wohlleben, Wendel

2013-04-01

Nanocomposite materials may be considered as a low-risk application of nanotechnology, if the nanofillers remain embedded throughout the life-cycle of the products in which they are embedded. We hypothesize that release of free CNTs occurs by a combination of mechanical stress and chemical degradation of the polymer matrix. We experimentally address limiting cases: Mechanically released fragments may show tubular protrusions on their surface. Here we identify these protrusions unambiguously as naked CNTs by chemically resolved microscopy and a suitable preparation protocol. By size-selective quantification of fragments we establish as a lower limit that at least 95 % of the CNTs remain embedded. Contrary to classical fiber composite approaches, we link this phenomenon to matrix materials with only a few percent elongation at break, predicting which materials should still cover their CNT nanofillers after machining. Protruding networks of CNTs remain after photochemical degradation of the matrix, and we show that it takes the worst case combinations of weathering plus high-shear wear to release free CNTs in the order of mg/m 2 /year. Synergy of chemical degradation and mechanical energy input is identified as the priority scenario of CNT release, but its lab simulation by combined methods is still far from real-world validation.

Surface contamination to UV-curable acrylates in the furniture and parquet industry.

Science.gov (United States)

Surakka, J; Lindh, T; Rosén, G; Fischer, T

2001-03-01

Surface contamination to ultraviolet radiation curable coatings (UV coatings), used increasingly in the parquet and furniture industry, is a matter of concern as a source for skin contamination. UV coatings contain chemically and biologically reactive acrylates, well known as skin contact irritants and sensitizers. Surface contamination may spread secondarily to equipment and other unexpected areas even outside the workplace. Yet, studies concerning this type of contamination are lacking due to lack of suitable sampling methods. Surface contamination of the work environment with risk for skin exposure to UV coating was measured employing a quantitative adhesive tape sampling method developed for this purpose. A pilot study was first performed at three workplaces to evaluate the contamination. In the main study, we wanted to locate and identify in detail the surface contamination of areas where problems exist, and to determine the extent of the problem. Measurements were performed at seven workplaces on two separate workdays (round 1 and 2) within a six-month period. Samples were collected from the workplaces based on the video monitoring of skin contact frequency with the surfaces and categorized into three groups to analyze risk. The pilot study indicated that surface contamination to TPGDA containing UV coatings was common, found in 76 percent of the surfaces, and varied with a maximum of 909 microg TPGDA 10 cm(-2) sampling area. In the main study TPGDA was found in 153 out of 196 collected samples (78.1%); for round one 78.1 percent (82 out of 105 samples) and for round two 78.0 percent (71 out of 91 samples). The average TPGDA mass on positive surface samples was on the first round 2,247 +/- 7,462 microg, and on the second round 2,960 +/- 4,590 microg. We conclude that surface contamination to uncured UV coatings at UV-curing lines is common and this involves a risk for harmful, unintentional skin exposure to acrylates.

Development of KMnO(4)-releasing composites for in situ chemical oxidation of TCE-contaminated groundwater.

Science.gov (United States)

Liang, S H; Chen, K F; Wu, C S; Lin, Y H; Kao, C M

2014-05-01

The objective of this study was to develop a controlled-oxidant-release technology combining in situ chemical oxidation (ISCO) and permeable reactive barrier (PRB) concepts to remediate trichloroethene (TCE)-contaminated groundwater. In this study, a potassium permanganate (KMnO4)-releasing composite (PRC) was designed for KMnO4 release. The components of this PRC included polycaprolactone (PCL), KMnO4, and starch with a weight ratio of 1.14:2:0.96. Approximately 64% (w/w) of the KMnO4 was released from the PRC after 76 days of operation in a batch system. The results indicate that the released KMnO4 could oxidize TCE effectively. The results from a column study show that the KMnO4 released from 200 g of PRC could effectively remediate 101 pore volumes (PV) of TCE-contaminated groundwater (initial TCE concentration = 0.5 mg/L) and achieve up to 95% TCE removal. The effectiveness of the PRC system was verified by the following characteristics of the effluents collected after the PRC columns (barrier): (1) decreased TCE concentrations, (2) increased ORP and pH values, and (3) increased MnO2 and KMnO4 concentrations. The results of environmental scanning electron microscope (ESEM) analysis show that the PCL and starch completely filled up the pore spaces of the PRC, creating a composite with low porosity. Secondary micro-scale capillary permeability causes the KMnO4 release, mainly through a reaction-diffusion mechanism. The PRC developed could be used as an ISCO-based passive barrier system for plume control, and it has the potential to become a cost-effective alternative for the remediation of chlorinated solvent-contaminated groundwater. Copyright © 2014 Elsevier Ltd. All rights reserved.

Geoscience of the Built Environment: Pollutants and Materials Surfaces

Directory of Open Access Journals (Sweden)

Jorge Sanjurjo-Sánchez

2011-12-01

Full Text Available An overview of issues with environmental relevance that arise from the interaction between pollutants and surfaces of the built environment is presented in this paper. Two broad perspectives are considered: decay of materials and recording of pollution characteristics. In relation to the former, we consider the possible implications on human activities restrictions, materials and morphological options, consumption of resources and release of pollutants resulting from the alteration of materials, conservation and restoration procedures. In terms of pollution recording, the interest of the stony materials as passive monitors of pollution, the question of heterogeneous conditions on buildings and the interest of qualitative and quantitative studies are highlighted. The importance of longitudinal studies on new and cleaned surfaces is considered, both for the understanding of materials decay and for the assessment of pollution conditions. The use of tracers to record the characteristics of pollution sources, interaction with materials and pathways of pollutants is also discussed. Finally, some recommendations are presented, based on the issues discussed on this paper that might be relevant for environmental management programs, including environmental education.

Understanding Contamination; Twenty Years of Simulating Radiological Contamination

Energy Technology Data Exchange (ETDEWEB)

Emily Snyder; John Drake; Ryan James

2012-02-01

A wide variety of simulated contamination methods have been developed by researchers to reproducibly test radiological decontamination methods. Some twenty years ago a method of non-radioactive contamination simulation was proposed at the Idaho National Laboratory (INL) that mimicked the character of radioactive cesium and zirconium contamination on stainless steel. It involved baking the contamination into the surface of the stainless steel in order to 'fix' it into a tenacious, tightly bound oxide layer. This type of contamination was particularly applicable to nuclear processing facilities (and nuclear reactors) where oxide growth and exchange of radioactive materials within the oxide layer became the predominant model for material/contaminant interaction. Additional simulation methods and their empirically derived basis (from a nuclear fuel reprocessing facility) are discussed. In the last ten years the INL, working with the Defense Advanced Research Projects Agency (DARPA) and the National Homeland Security Research Center (NHSRC), has continued to develop contamination simulation methodologies. The most notable of these newer methodologies was developed to compare the efficacy of different decontamination technologies against radiological dispersal device (RDD, 'dirty bomb') type of contamination. There are many different scenarios for how RDD contamination may be spread, but the most commonly used one at the INL involves the dispersal of an aqueous solution containing radioactive Cs-137. This method was chosen during the DARPA projects and has continued through the NHSRC series of decontamination trials and also gives a tenacious 'fixed' contamination. Much has been learned about the interaction of cesium contamination with building materials, particularly concrete, throughout these tests. The effects of porosity, cation-exchange capacity of the material and the amount of dirt and debris on the surface are very important factors

Process for surface treatment of zirconium-containing cladding materials for fuel element or other components for nuclear reactors

International Nuclear Information System (INIS)

Videm, K.G.; Lunde, L.R.; Kooyman, H.H.

1975-01-01

A process for the surface treatment of zirconium-base cladding materials for fuel elements or other components for nuclear reactors is described. The treatment includes pickling the cladding material in a fluoride-containing bath, and then applying a protective coating through oxidation to the pickled cladding material. The fluoride-containing contaminants which remain on the surface of the cladding material during pickling are removed or rendered harmless by anodic oxidation

Quantification of surface contamination: principles and applications

International Nuclear Information System (INIS)

Vo-Dinh, T.

1982-01-01

The applications discussed in this paper underscore the usefulness and versatility of molecular luminescence spectroscopy as an efficient surface detection technique. The technique can be used not only as a qualitative characterization method, but also as a quantitative analytical tool to detect trace contaminants on surfaces. Recent advances in instrumentation and methodology have expanded the applicability of surface luminescence into many new problem areas. Trace organics are emphasized here

Release of powdered material from waste packages

International Nuclear Information System (INIS)

Berg, H.P.; Gruendler, D.; Peiffer, F.; Seehars, H.D.

1990-01-01

Possible incidents in the operational phase of the planned German repository KONRAD for radioactive waste with negligible heat production were investigated to assess the radiological consequences. For these investigations release fractions of the radioactive materials are required. This paper deals with the determination of the release of powdered material from waste packages under mechanical stress. These determinations were based on experiments. The experimental procedure and the process parameters chosen in accordance with the conditions in the planned repository will be described. The significance of the experimental results is discussed with respect to incidents in the planned repository. 8 figs., 3 tabs

Wind effected redistribution of surface contamination. Progress report, September 1974--August 1975

International Nuclear Information System (INIS)

Amato, A.J.

1975-01-01

Theoretical resuspension ratios were computed through the extension of a one-dimensional model used to simulate the wind effected movement of surface contaminants. The surface movement of contamination associated with inhalable size particles was considered in relation to time, space, wind velocity, distance from the source, soil resuspension ratios, and other variables. A computer program was developed to calculate the wind effected distribution of surface contaminants. (U.S.)

Monitoring of Water and Contaminant Migration at the Groundwater-Surface Water Interface

Science.gov (United States)

2008-08-01

seepage is occurring in a freshwater lake environment and to map the lateral extent of any subsurface contamination at the groundwater –surface water ...and Contaminant Migration at the Groundwater -Surface Water Interface August 2008 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public...4. TITLE AND SUBTITLE Monitoring of Water and Contaminant Migration at the Groundwater -Surface Water Interface 5a. CONTRACT NUMBER 5b. GRANT NUMBER

Radioactive contamination of nest materials of the Eurasian Tree Sparrow Passer montanus due to the Fukushima nuclear accident: The significance in the first year

International Nuclear Information System (INIS)

Matsui, Shin; Kasahara, Satoe; Morimoto, Gen; Mikami, Osamu K.; Watanabe, Mamoru; Ueda, Keisuke

2015-01-01

The 2011 Fukushima nuclear accident contaminated large areas of eastern and northeastern Japan, releasing vast amounts of radiation. Here we investigated radioactive contamination of the nest materials of the Eurasian Tree Sparrow Passer montanus from the breeding season of 2011 directly after the accident to the next breeding season of 2012 at two sites. In Tokyo (222 km southwest of the plant), ambient dose rates in the nestboxes were lower than those in Ibaraki (175 km southwest of the plant), where the levels of 2011 were higher than those of 2012. Further, the amount of radioactive Cs in each nest increased with the increase in nest weight, with a higher increment at Ibaraki than at Tokyo. These data suggested higher nest contamination levels in the breeding season directly after a nuclear accident than in later seasons, and an increment of nest contamination levels via nest materials of birds. - Highlights: • We describe radioactive contamination of bird nests after the Fukushima accident. • The amount of radioactive Cs inside the nestboxes increased with the nest weight. • Nest contamination has the potential to amplify effects of radiation on birds. - Radioactive Cs included in the nest materials of birds increased nest contamination levels.

Tritium saturation in plasma-facing materials surfaces

International Nuclear Information System (INIS)

Longhurst, G.R.; Anderl, R.A.; Pawelko, R.J.; Causey, R.A.; Federici, G.; Haasz, A.A.

1998-01-01

Plasma-facing components in the international thermonuclear experimental reactor (ITER) will experience high heat loads and intense plasma fluxes of order 10 20 -10 23 particles/m 2 s. Experiments on Be and W, two of the materials considered for use in ITER, have revealed that a tritium saturation phenomenon can take place under these conditions in which damage to the surface results that enhances the return of implanted tritium to the plasma and inhibits uptake of tritium. This phenomenon is important because it implies that tritium inventories due to implantation in these plasma-facing materials will probably be lower than was previously estimated using classical recombination-limited release at the plasma surface. Similarly, permeation through these components to the coolant streams should be reduced. In this paper we discuss evidences for the existence of this phenomenon, describe techniques for modeling it, and present results of the application of such modeling to prior experiments. (orig.)

Tritium saturation in plasma-facing materials surfaces

Energy Technology Data Exchange (ETDEWEB)

Longhurst, G.R.; Anderl, R.A.; Pawelko, R.J. [Idaho Nat. Eng. and Environ. Lab., Idaho Falls, ID (United States); Causey, R.A. [Sandia National Labs., Livermore, CA (United States); Federici, G. [ITER Garching Joint Work Site, Garching (Germany); Haasz, A.A. [Toronto Univ., ON (Canada). Inst. for Aerospace Studies

1998-10-01

Plasma-facing components in the international thermonuclear experimental reactor (ITER) will experience high heat loads and intense plasma fluxes of order 10{sup 20}-10{sup 23} particles/m{sup 2}s. Experiments on Be and W, two of the materials considered for use in ITER, have revealed that a tritium saturation phenomenon can take place under these conditions in which damage to the surface results that enhances the return of implanted tritium to the plasma and inhibits uptake of tritium. This phenomenon is important because it implies that tritium inventories due to implantation in these plasma-facing materials will probably be lower than was previously estimated using classical recombination-limited release at the plasma surface. Similarly, permeation through these components to the coolant streams should be reduced. In this paper we discuss evidences for the existence of this phenomenon, describe techniques for modeling it, and present results of the application of such modeling to prior experiments. (orig.) 39 refs.

Exploring Surface Analysis Techniques for the Detection of Molecular Contaminants on Spacecraft

Science.gov (United States)

Rutherford, Gugu N.; Seasly, Elaine; Thornblom, Mark; Baughman, James

2016-01-01

Molecular contamination is a known area of concern for spacecraft. To mitigate this risk, projects involving space flight hardware set requirements in a contamination control plan that establishes an allocation budget for the exposure of non-volatile residues (NVR) onto critical surfaces. The purpose of this work will focus on non-contact surface analysis and in situ monitoring to mitigate molecular contamination on space flight hardware. By using Scanning Electron Microscopy and Energy Dispersive Spectroscopy (SEM-EDS) with Raman Spectroscopy, an unlikely contaminant was identified on space flight hardware. Using traditional and surface analysis methods provided the broader view of the contamination sources allowing for best fit solutions to prevent any future exposure.

Assessment of Surface Water Contamination from Coalbed Methane Fracturing-Derived Volatile Contaminants in Sullivan County, Indiana, USA.

Science.gov (United States)

Meszaros, Nicholas; Subedi, Bikram; Stamets, Tristan; Shifa, Naima

2017-09-01

There is a growing concern over the contamination of surface water and the associated environmental and public health consequences from the recent proliferation of hydraulic fracturing in the USA. Petroleum hydrocarbon-derived contaminants of concern [benzene, toluene, ethylbenzene, and xylenes (BTEX)] and various dissolved cations and anions were spatially determined in surface waters around 15 coalbed methane fracking wells in Sullivan County, IN, USA. At least one BTEX compound was detected in 69% of sampling sites (n = 13) and 23% of sampling sites were found to be contaminated with all of the BTEX compounds. Toluene was the most common BTEX compound detected across all sampling sites, both upstream and downstream from coalbed methane fracking wells. The average concentration of toluene at a reservoir and its outlet nearby the fracking wells was ~2× higher than other downstream sites. However, one of the upstream sites was found to be contaminated with BTEX at similar concentrations as in a reservoir site nearby the fracking well. Calcium (~60 ppm) and sulfates (~175 ppm) were the dominant cations and anions, respectively, in surface water around the fracking sites. This study represents the first report of BTEX contamination in surface water from coalbed methane hydraulic fracturing wells.

The Importance of Particle Size in Estimating Downwind Contamination from an RDD

International Nuclear Information System (INIS)

Bauer, T.

2007-01-01

There is general agreement that realistic quantities of radiological material released from a radiological dispersal device (RDD) will not travel more than hundred meters at toxic levels. Of greater concern in the case of such an incident is the size of the area contaminated with radiological particles. Remediation of contaminated areas will require either removal of the deposited articles or disposal of the contaminated materials. Contours of expected contaminated areas have been presented which extend more than 10 miles downwind of the release location. It would be impossible to remediate such a large area, so the likely response will be to permanently seal most of it off from further use. Not only are these radiation contours below levels of concern, the particle size assumed is unreasonably low, especially when the density of radioactive materials is considered. Using of appropriate RDD characterization and range of particle size, this presentation will show that expected contamination areas should be small enough to make remediation feasible.(author)

Bacteria contamination of touch surfaces in Polish hospital wards

Directory of Open Access Journals (Sweden)

Anna Różańska

2017-08-01

Full Text Available Background: The objective of the study has been to evaluate the pathogenic bacteria contamination of touch surfaces in hospital wards. Material and Methods: Samples were taken from frequently touched surfaces in the hospital environment in 13 units of various types. Culturing was carried out on solid blood agar and in growth broth (tryptic soy broth – TSB. Species identification was performed using the analytical profile index (API biochemical testing and confirmed with matrix assisted laser desorption ionization time-flight mass spectrometry (MALDI-TOF-MS system. Results: The total of 161 samples were taken for the study. Fifty-two of them, after 24 h of culture on a solid medium, demonstrated bacterial growth and further 60 samples had growth after prior multiplication in TSB. Overall, 69.6% of samples exhibited growth of 19 bacterial species. Pathogenic species – representing indicator organisms of efficiency of hospital cleaning – was demonstrated by 21.4% of samples. Among them Acinetobacter spp., Enterocococci spp. and Staphylococcus aureus were identified. Coagulase-negative staphylococci (CNS were predominant. The proportion of various groups of bacteria significantly varied in respective hospitals, and in various types of wards. Disturbing observation is a large proportion of resistance of isolated CNS strains as a potential reservoir of resistance genes. Conclusions: The results show that touch surfaces in hospital units are contaminated by both potentially pathogenic and pathogenic bacterial species. In connection with the reported, also in Poland, frequent omission or incorrect execution of hand hygiene by hospital staff, and probably patients, touch surfaces still constitute important reservoir of pathogenic bacteria. Improving hand hygiene compliance of health-care workers with recommendations is necessary for increasing biological safety of hospital environment. Med Pr 2017;68(3:459–467

Solid phase speciation of arsenic by sequential extraction in standard reference materials and industrially contaminated soil samples

International Nuclear Information System (INIS)

Herreweghe, Samuel van; Swennen, Rudy; Vandecasteele, Carlo; Cappuyns, Valerie

2003-01-01

Leaching experiments, a mineralogical survey and larger samples are preferred when arsenic is present as discrete mineral phases. - Availability, mobility, (phyto)toxicity and potential risk of contaminants is strongly affected by the manner of appearance of elements, the so-called speciation. Operational fractionation methods like sequential extractions have been applied for a long time to determine the solid phase speciation of heavy metals since direct determination of specific chemical compounds can not always be easily achieved. The three-step sequential extraction scheme recommended by the BCR and two extraction schemes based on the phosphorus-like protocol proposed by Manful (1992, Occurrence and Ecochemical Behaviours of Arsenic in a Goldsmelter Impacted Area in Ghana, PhD dissertation, at the RUG) were applied to four standard reference materials (SRM) and to a batch of samples from industrially contaminated sites, heavily contaminated with arsenic and heavy metals. The SRM 2710 (Montana soil) was found to be the most useful reference material for metal (Mn, Cu, Zn, As, Cd and Pb) fractionation using the BCR sequential extraction procedure. Two sequential extraction schemes were developed and compared for arsenic with the aim to establish a better fractionation and recovery rate than the BCR-scheme for this element in the SRM samples. The major part of arsenic was released from the heavily contaminated samples after NaOH-extraction. Inferior extraction variability and recovery in the heavily contaminated samples compared to SRMs could be mainly contributed to subsample heterogeneity

The Risoe model for calculating the consequences of the release of radioactive material to the atmosphere

International Nuclear Information System (INIS)

Thykier-Nielsen, S.

1980-07-01

A brief description is given of the model used at Risoe for calculating the consequences of releases of radioactive material to the atmosphere. The model is based on the Gaussian plume model, and it provides possibilities for calculation of: doses to individuals, collective doses, contamination of the ground, probability distribution of doses, and the consequences of doses for give dose-risk relationships. The model is implemented as a computer program PLUCON2, written in ALGOL for the Burroughs B6700 computer at Risoe. A short description of PLUCON2 is given. (author)

Controlled release fertilizer increased phytoremediation of petroleum-contaminated sandy soil.

Science.gov (United States)

Cartmill, Andrew D; Cartmill, Donita L; Alarcón, Alejandro

2014-01-01

A greenhouse experiment was conducted to determine the effect of the application of controlled release fertilizer [(CRF) 0, 4,6, or 8 kg m(-3)] on Lolium multiflorum Lam. survival and potential biodegradation of petroleum hydrocarbons (0, 3000, 6000, or 15000 mg kg(-1)) in sandy soil. Plant adaptation, growth, photosynthesis, total chlorophyll, and proline content as well as rhizosphere microbial population (culturable heterotrophic fungal and bacterial populations) and total petroleum hydrocarbon (TPH)-degradation were determined. Petroleum induced-toxicity resulted in reduced plant growth, photosynthesis, and nutrient status. Plant adaptation, growth, photosynthesis, and chlorophyll content were enhanced by the application of CRF in contaminated soil. Proline content showed limited use as a physiological indicator of petroleum induced-stress in plants. Bacterial and filamentous fungi populations were stimulated by the petroleum concentrations. Bacterial populations were stimulated by CRF application. At low petroleum contamination, CRF did not enhance TPH-degradation. However, petroleum degradation in the rhizosphere was enhanced by the application of medium rates of CRF, especially when plants were exposed to intermediate and high petroleum contamination. Application of CRF allowed plants to overcome the growth impairment induced by the presence of petroleum hydrocarbons in soils.

Hanford Site Tank 241-C-108 Residual Waste Contaminant Release Models and Supporting Data

Energy Technology Data Exchange (ETDEWEB)

Cantrell, Kirk J.; Krupka, Kenneth M.; Geiszler, Keith N.; Arey, Bruce W.; Schaef, Herbert T.

2010-06-18

This report presents the results of laboratory characterization, testing, and analysis for a composite sample (designated 20578) of residual waste collected from single-shell tank C-108 during the waste retrieval process after modified sluicing. These studies were completed to characterize concentration and form of contaminant of interest in the residual waste; assess the leachability of contaminants from the solids; and develop release models for contaminants of interest. Because modified sluicing did not achieve 99% removal of the waste, it is expected that additional retrieval processing will take place. As a result, the sample analyzed here is not expected to represent final retrieval sample.

Resistance to disinfection of a polymicrobial association contaminating the surface of elastomeric dental impressions.

Science.gov (United States)

Giammanco, Giovanni M; Melilli, Dario; Rallo, Antonio; Pecorella, Sonia; Mammina, Caterina; Pizzo, Giuseppe

2009-04-01

The aim of this study was to evaluate the ability to resist disinfection of a polymicrobial association contaminating the surface of dental impressions obtained with two different elastomers: a polyether (Impregum) and an addition-polymerized silicone (Elite). Impressions were contaminated with a mixture of three biofilm-forming microorganisms (Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans) and disinfected immediately after contamination, or after microbial layers were allowed to develop during a six-hour storage. Two commercial disinfectants were tested: MD 520 containing 0.5% glutaraldehyde and Sterigum Powder without glutaraldehyde. Residual contamination was recovered by mechanical rinsing immediately after disinfection and after a six-hour storage of disinfected impressions, and assessed by colony counting. Both disinfectants tested were shown to be effective in reducing the microbial presence on the impression materials, achieving at least a 102 reduction of microbial counts compared to water rinsing. However, Sterigum was generally less effective on the Elite elastomer and could not grant disinfection on six-hour aged P. aeruginosa and C. albicans microbial layers. The results of this study suggest that the materials used for the impressions influence the efficacy of disinfection. Disinfectants should be tested according to conditions encountered in everyday clinical practice and the need for immediate disinfection of impressions should be clearly indicated by manufacturers.

SUDOQU: a new dose model to derive criteria for surface contamination of non-food (consumer) goods, containers and conveyances

International Nuclear Information System (INIS)

Van Dillen, Teun

2015-01-01

The Fukushima nuclear accident (Japan, 11 March 2011) revealed the need for well-founded criteria for surface contamination and associated screening levels related to the import of non-food (consumer) goods, containers and conveyances. The only available European-harmonised criteria are those laid down in the IAEA transport regulations, but these criteria date back from the early 1960's and only apply to the safe transport of radioactive materials. The main problem is that a generic dose-assessment model for consumer products is missing. Therefore, RIVM (National Institute for Public Health and the Environment) developed a new methodology entitled SUDOQU (Surface Dose Quantification) to calculate the annual effective dose for both consumers and non-radiological workers, addressing issues of removability of surface contamination. The methodology can be used to derive criteria and screening levels for surface contamination and could serve as a useful tool for policy-makers and radiation-protection specialists. (authors)

Corrective Action Decision Document for Corrective Action Unit 168: Area 25 and 26 Contaminated Materials and Waste Dumps, Nevada Test Site, Nevada, Rev. No.: 2 with Errata Sheet

Energy Technology Data Exchange (ETDEWEB)

Wickline, Alfred

2006-12-01

This Corrective Action Decision Document has been prepared for Corrective Action Unit (CAU) 168: Area 25 and 26, Contaminated Materials and Waste Dumps, Nevada Test Site, Nevada. The purpose of this Corrective Action Decision Document is to identify and provide a rationale for the selection of a recommended corrective action alternative for each corrective action site (CAS) within CAU 168. The corrective action investigation (CAI) was conducted in accordance with the ''Corrective Action Investigation Plan for Corrective Action Unit 168: Area 25 and 26, Contaminated Materials and Waste Dumps, Nevada Test Site, Nevada'', as developed under the ''Federal Facility Agreement and Consent Order'' (1996). Corrective Action Unit 168 is located in Areas 25 and 26 of the Nevada Test Site, Nevada and is comprised of the following 12 CASs: CAS 25-16-01, Construction Waste Pile; CAS 25-16-03, MX Construction Landfill; CAS 25-19-02, Waste Disposal Site; CAS 25-23-02, Radioactive Storage RR Cars; CAS 25-23-13, ETL - Lab Radioactive Contamination; CAS 25-23-18, Radioactive Material Storage; CAS 25-34-01, NRDS Contaminated Bunker; CAS 25-34-02, NRDS Contaminated Bunker; CAS 25-99-16, USW G3; CAS 26-08-01, Waste Dump/Burn Pit; CAS 26-17-01, Pluto Waste Holding Area; and CAS 26-19-02, Contaminated Waste Dump No.2. Analytes detected during the CAI were evaluated against preliminary action levels (PALs) to determine contaminants of concern (COCs) for CASs within CAU 168. Radiological measurements of railroad cars and test equipment were compared to unrestricted (free) release criteria. Assessment of the data generated from the CAI activities revealed the following: (1) Corrective Action Site 25-16-01 contains hydrocarbon-contaminated soil at concentrations exceeding the PAL. The contamination is at discrete locations associated with asphalt debris. (2) No COCs were identified at CAS 25-16-03. Buried construction waste is present in at least two

Characterization of new functionalized calcium carbonate-polycaprolactone composite material for application in geometry-constrained drug release formulation development.

Science.gov (United States)

Wagner-Hattler, Leonie; Schoelkopf, Joachim; Huwyler, Jörg; Puchkov, Maxim

2017-10-01

A new mineral-polymer composite (FCC-PCL) performance was assessed to produce complex geometries to aid in development of controlled release tablet formulations. The mechanical characteristics of a developed material such as compactibility, compressibility and elastoplastic deformation were measured. The results and comparative analysis versus other common excipients suggest efficient formation of a complex, stable and impermeable geometries for constrained drug release modifications under compression. The performance of the proposed composite material has been tested by compacting it into a geometrically altered tablet (Tablet-In-Cup, TIC) and the drug release was compared to commercially available product. The TIC device exhibited a uniform surface, showed high physical stability, and showed absence of friability. FCC-PCL composite had good binding properties and good compactibility. It was possible to reveal an enhanced plasticity characteristic of a new material which was not present in the individual components. The presented FCC-PCL composite mixture has the potential to become a successful tool to formulate controlled-release dosage solid forms.

Modelling of contamination of surface atmosphere for deflation of Cesium-137 on contaminated territories

International Nuclear Information System (INIS)

Bogdanov, A.P.; Zhmura, G.M.

1994-01-01

Presence of Cesium 137 in near land air is caused at the contaminated territories by 'local' dusting and transport of the dust from the zone of strong contamination. For large distance is it caused by resuspension of radioactive dust from the surface in the given region. In accordance with the models of dusting round square sources based on Gauss statistical model of dissemination of admixtures in the atmosphere, the contaminated areas of european part of the former of USSR with the density of contamination over 1 Ci/km 2 with Cesium 137 were represented by 30 round square sources covering the main spots of contamination. The results of calculation of contamination of the atmosphere for several cities of Belarus, Russia and Ukraine, where there are the permanent points of observation for the content of radionuclides in the air, have shown that the proposed model of dusting sources describes the contamination of near land air with Cesium 137 reasonably well. 7 refs., 3 tabs

Radiative Transfer Model for Contaminated Rough Surfaces

Science.gov (United States)

2013-02-01

reflectance of potassium chlorate and ammonium nitrate contaminated surfaces in mid-wavelength and long-wavelength infrared for detection. Our framework...obtained excellent or good results for lab measurements of potassium chlorate on most aluminum surfaces; however, ammonium nitrate on painted aluminum...misidentify potassium chlorate as ammonium nitrate and vice versa). We also observed moderate success on field data. 15. SUBJECT TERMS radiative

Automated radiological scanning of potentially contaminated railroad crossties for free-release or disposal

International Nuclear Information System (INIS)

Hochel, R.C.

1996-06-01

The Savannah River Site (SRS) has accumulated approximately 300,000 crossties that have been replaced over a 40-year period of maintaining the site's 62 miles of railroad track. The ties reside in a pile on an open area of 2.3 acres near the site's F-Area facilities. A small fraction of the ties are potentially contaminated with radioactivity as a result of past site practices and service. Contamination was possible from occasional leaks in transport-casks moved by rail from the site's five nuclear materials production reactors to its two reprocessing facilities. Casks typically were filled with spent fuel, targets, and water from the reactor disassembly basins, which contained small amounts of fission and neutron activation product radioactivity normal to the operation of nuclear reactors. What to do with the ties has been debated for sometime. Proposals have ranged from simple burial, to bio-remediation, to burning as a fuel in the site's powerhouse, to free-release to off-site markets. In the past, burial was the disposal method of choice; however, the Department of Energy (DOE) order 5820.2A and premium on new space for low-level waste largely rule out burial. Instead, the last option is now cost effective and was begun under a contract with National Environmental Services Corporation started in January, 1996

GWSCREEN: A semi-analytical model for assessment of the groundwater pathway from surface or buried contamination: Theory and user's manual

International Nuclear Information System (INIS)

Rood, A.S.

1992-03-01

GWSCREEN was developed for assessment of the groundwater pathway from leaching of radioactive and non radioactive substances from surface or buried sources. The code was designed for implementation in the Track 1 and Track 2 assessment of Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) sites identified as low probability hazard at the Idaho National Engineering Laboratory (DOE, 1991). The code calculates the limiting soil concentration such that regulatory contaminant levels in groundwater are not exceeded. The code uses a mass conservation approach to model three processes: Contaminant release from a source volume, contaminant transport in the unsaturated zone, and contaminant transport in the saturated zone. The source model considers the sorptive properties and solubility of the contaminant. Transport in the unsaturated zone is described by a plug flow model. Transport in the saturated zone is calculated with a semi-analytical solution to the advection dispersion equation for transient mass flux input

Measuring hypoxia induced metal release from highly contaminated estuarine sediments during a 40 day laboratory incubation experiment

Energy Technology Data Exchange (ETDEWEB)

Banks, Joanne L., E-mail: jlbanks@student.unimelb.edu.au [Department of Zoology, University of Melbourne, Victoria, 3010 Australia (Australia); Ross, D. Jeff, E-mail: Jeff.Ross@utas.edu.au [Institute of Marine and Antarctic Studies, Nubeena Crescent, Taroona, Tasmania, 7053 Australia (Australia); Keough, Michael J., E-mail: mjkeough@unimelb.edu.au [Department of Zoology, University of Melbourne, Victoria, 3010 Australia (Australia); Eyre, Bradley D., E-mail: bradley.eyre@scu.edu.au [Centre for Coastal Biogeochemistry, School of Environmental Science and Management, Southern Cross University, PO Box 157, Lismore, NSW, 2480 Australia (Australia); Macleod, Catriona K., E-mail: Catriona.Macleod@utas.edu.au [Institute of Marine and Antarctic Studies, Nubeena Crescent, Taroona, Tasmania, 7053 Australia (Australia)

2012-03-15

Nutrient inputs to estuarine and coastal waters worldwide are increasing and this in turn is increasing the prevalence of eutrophication and hypoxic and anoxic episodes in these systems. Many urbanised estuaries are also subject to high levels of anthropogenic metal contamination. Environmental O{sub 2} levels may influence whether sediments act as sinks or sources of metals. In this study we investigated the effect of an extended O{sub 2} depletion event (40 days) on fluxes of trace metals (and the metalloid As) across the sediment-water interface in sediments from a highly metal contaminated estuary in S.E. Tasmania, Australia. We collected sediments from three sites that spanned a range of contamination and measured total metal concentration in the overlying water using sealed core incubations. Manganese and iron, which are known to regulate the release of other divalent cations from sub-oxic sediments, were released from sediments at all sites as hypoxia developed. In contrast, the release of arsenic, cadmium, copper and zinc was comparatively low, most likely due to inherent stability of these elements within the sediments, perhaps as a result of their refractory origin, their association with fine-grained sediments or their being bound in stable sulphide complexes. Metal release was not sustained due to the powerful effect of metal-sulphide precipitation of dissolved metals back into sediments. The limited mobilisation of sediment bound metals during hypoxia is encouraging, nevertheless the results highlight particular problems for management in areas where hypoxia might occur, such as the release of metals exacerbating already high loads or resulting in localised toxicity. - Highlights: Black-Right-Pointing-Pointer Metal contaminated sediments exposed to long-term hypoxia released Mn and Fe pulses. Black-Right-Pointing-Pointer As flux increased under anoxic conditions Cd, Cu and Zn fluxes occurred only during the first week of hypoxia. Black

Measuring hypoxia induced metal release from highly contaminated estuarine sediments during a 40 day laboratory incubation experiment

International Nuclear Information System (INIS)

Banks, Joanne L.; Ross, D. Jeff; Keough, Michael J.; Eyre, Bradley D.; Macleod, Catriona K.

2012-01-01

Nutrient inputs to estuarine and coastal waters worldwide are increasing and this in turn is increasing the prevalence of eutrophication and hypoxic and anoxic episodes in these systems. Many urbanised estuaries are also subject to high levels of anthropogenic metal contamination. Environmental O 2 levels may influence whether sediments act as sinks or sources of metals. In this study we investigated the effect of an extended O 2 depletion event (40 days) on fluxes of trace metals (and the metalloid As) across the sediment–water interface in sediments from a highly metal contaminated estuary in S.E. Tasmania, Australia. We collected sediments from three sites that spanned a range of contamination and measured total metal concentration in the overlying water using sealed core incubations. Manganese and iron, which are known to regulate the release of other divalent cations from sub-oxic sediments, were released from sediments at all sites as hypoxia developed. In contrast, the release of arsenic, cadmium, copper and zinc was comparatively low, most likely due to inherent stability of these elements within the sediments, perhaps as a result of their refractory origin, their association with fine-grained sediments or their being bound in stable sulphide complexes. Metal release was not sustained due to the powerful effect of metal-sulphide precipitation of dissolved metals back into sediments. The limited mobilisation of sediment bound metals during hypoxia is encouraging, nevertheless the results highlight particular problems for management in areas where hypoxia might occur, such as the release of metals exacerbating already high loads or resulting in localised toxicity. - Highlights: ► Metal contaminated sediments exposed to long-term hypoxia released Mn and Fe pulses. ► As flux increased under anoxic conditions Cd, Cu and Zn fluxes occurred only during the first week of hypoxia. ► Flux of these metals from 3 sites was not related to total sediment metal

Regulatory Initiatives for Control and Release of Technologically Enhanced Naturally-Occurring Radioactive Material

International Nuclear Information System (INIS)

Egidi, P.V.

1999-01-01

Current drafts of proposed standards and suggested State regulations for control and release of technologically-enhanced naturally-occurring radioactive material (TENORM), and standards for release of volumetrically-contaminated material in the US are reviewed. These are compared to the recommendations of the International Atomic Energy Association (IAEA) Safety Series and the European Commission (EC) proposals. Past regulatory efforts with respect to TENORM in the US dealt primarily with oil-field related wastes. Currently, nine states (AK, GA, LA, MS, NM, OH, OR SC, TX) have specific regulations pertaining to TENORM, mostly based on uranium mill tailings cleanup criteria. The new US proposals are dose- or risk-based, as are the IAEA and EC recommendations, and are grounded in the linear no threshold hypothesis (LNT). TENORM wastes involve extremely large volumes, particularly scrap metal and mine wastes. Costs to control and dispose of these wastes can be considerable. The current debate over the validity of LNT at low doses and low dose rates is particularly germane to this discussion. Most standards setting organizations and regulatory agencies base their recommendations on the LNT. The US Environmental Protection Agency has released a draft Federal Guidance Report that recommends calculating health risks from low-level exposure to radionuclides based on the LNT. However, some scientific and professional organizations are openly questioning the validity of LNT and its basis for regulations, practices, and costs to society in general. It is not clear at this time how a non-linear regulatory scheme would be implemented

Regulatory Initiatives for Control and Release of Technologically Enhanced Naturally-Occurring Radioactive Materials

Energy Technology Data Exchange (ETDEWEB)

Egidi, P.V.

1999-03-02

Current drafts of proposed standards and suggested State regulations for control and release of technologically-enhanced naturally-occurring radioactive material (TENORM), and standards for release of volumetrically-contaminated material in the US are reviewed. These are compared to the recommendations of the International Atomic Energy Association (IAEA) Safety Series and the European Commission (EC) proposals. Past regulatory efforts with respect to TENORM in the US dealt primarily with oil-field related wastes. Currently, nine states (AK, GA, LA, MS, NM, OH, OR SC, TX) have specific regulations pertaining to TENORM, mostly based on uranium mill tailings cleanup criteria. The new US proposals are dose- or risk-based, as are the IAEA and EC recommendations, and are grounded in the linear no threshold hypothesis (LNT). TENORM wastes involve extremely large volumes, particularly scrap metal and mine wastes. Costs to control and dispose of these wastes can be considerable. The current debate over the validity of LNT at low doses and low dose rates is particularly germane to this discussion. Most standards setting organizations and regulatory agencies base their recommendations on the LNT. The US Environmental Protection Agency has released a draft Federal Guidance Report that recommends calculating health risks from low-level exposure to radionuclides based on the LNT. However, some scientific and professional organizations are openly questioning the validity of LNT and its basis for regulations, practices, and costs to society in general. It is not clear at this time how a non-linear regulatory scheme would be implemented.

Residual viral and bacterial contamination of surfaces after cleaning and disinfection

NARCIS (Netherlands)

Tuladhar, E.; Hazeleger, W.C.; Koopmans, M.; Zwietering, M.H.; Beumer, R.R.; Duizer, E.

2012-01-01

Environmental surfaces contaminated with pathogens can be sources of indirect transmission, and cleaning and disinfection are common interventions focused on reducing contamination levels. We determined the efficacy of cleaning and disinfection procedures for reducing contamination by noroviruses,

Chemical resilience of clay rich barrier materials to redox-oscillating conditions and implications for contaminant mobility

International Nuclear Information System (INIS)

Parsons, Chris; Rossetto, Lionel; Charlet, Laurent; Made, Benoit

2012-01-01

Document available in extended abstract form only. The mineralogical composition of argillaceous barrier materials is often considered to be static, and therefore, that interactions with contaminants and nutrients may be well constrained. Typically, solid/aqueous partition coefficients (K d values) are obtained empirically to determine the proportion of contaminant immobilised by the solid phase for individual barrier material/contaminant combinations at defined contaminant loadings and pH. These values may then be used as indicators of potential contaminant mobility around waste storage facilities following the eventual failure of engineered barriers (1). While K d values are a useful tool to modellers estimating contaminant mobility through porous media at thermodynamic equilibrium, over time and under dynamic biogeochemical conditions, matrix mineralogy, and therefore K d values, are liable to change (2). Near surface environments implicated in back-filled or excavated storage solutions, currently proposed for low-level long-lived waste (LL-LLW), will result in more dynamic redox conditions than those predicted in deep, anoxic geological storage conditions (2). Such dynamic conditions are similar to those experienced in pluvial, fluvial or phreatic influenced soils and are likely to be far from thermodynamic equilibrium (3). Cyclic redox conditions of varying periodicity are likely to occur around near surface repositories due to a combination of microbial activity and variations in substrate saturation caused by changes to groundwater level and rates of pluvial infiltration. Upon saturation of near surface substrates reducing conditions occur rapidly due to slow inward diffusion of oxygen from the surface and rapid oxygen consumption by aerobic heterotrophic bacteria gaining energy from the mineralisation of organic matter (4, 5). Subsequent to the exhaustion of residual oxygen, anaerobic metabolism dominates in such environments resulting in the depletion of

Radioactive contamination of natural and artificial materials

International Nuclear Information System (INIS)

Kovalchuk, E.L.; Pomansky, A.A.; Smolnikov, A.A.; Temmoev, A.H.

1980-01-01

The gamma radiation of different materials was measured in an underground low-background chamber with extraordinary background characteristics. The excellent background conditions of the measurements enabled investigators to see the alpha-particle peaks of the internal radioactive contamination of NaI(Tl) detectors, which were especially made for these measurements. The sensitivity limit of the installation was determined by the internal contamination of the NaI(Tl) detectors alone. Any radiation background, except for three substances, tungsten, copper, and brass, could be registered

Corrective Action Decision Document for Corrective Action Unit 166: Storage Yards and Contaminated Materials, Nevada Test Site, Nevada with Errata Sheet

Energy Technology Data Exchange (ETDEWEB)

Grant Evenson

2007-03-01

This Corrective Action Decision Document (CADD) has been prepared for Corrective Action Unit (CAU) 166, Storage Yards and Contaminated Materials, in accordance with the Federal Facility Agreement and Consent Order (1996). The corrective action sites (CASs) are located in Areas 2, 3, 5, and 18 of the Nevada Test Site, Nevada. Corrective Action Unit 166 is comprised of the following CASs: • 02-42-01, Cond. Release Storage Yd - North • 02-42-02, Cond. Release Storage Yd - South • 02-99-10, D-38 Storage Area • 03-42-01, Conditional Release Storage Yard • 05-19-02, Contaminated Soil and Drum • 18-01-01, Aboveground Storage Tank • 18-99-03, Wax Piles/Oil Stain The purpose of this CADD is to identify and provide the rationale for the recommendation of a corrective action alternative (CAA) for the seven CASs within CAU 166. Corrective action investigation (CAI) activities were performed from July 31, 2006, through February 28, 2007, as set forth in the CAU 166 Corrective Action Investigation Plan (NNSA/NSO, 2006).

Experiment on Physical Desalinisation of Uranium-contaminated Gravel Surface

International Nuclear Information System (INIS)

Park, Uk-Ryang; Kim, Gye-Nam; Kim, Seung-Soo; Han, Gyu-Seong; Moon, Jai-Kwon

2014-01-01

As a result, the method to wash uranium-contaminated gravels could not get satisfactory desalinization rate. During the long oxidization process it was judged that uranium penetrated inside the gravels, so we tried to increase the desalinization rate by fragmentizing them into pieces and then washing them. The desalinization rate after fragmentizing the gravels into pieces and washing them brought a satisfactory result.. However, we could obtain desired concentration for gravels with high uranium concentration by fragmentizing them and breaking them further into even smaller pieces. Likewise, desalinization using soil washing process is complicated and has to go through multiple washing steps, resulting in too much of waste fluid generated accordingly. The increase of waste fluid generated leads to the increase in by-products of the final disposal process later on, bringing a not good economic result. Furthermore, taking into account that the desalinization rate is 65% during soil washing process, it is expected that gravel washing will show a similar desalinization result; it is considered uneasy to have a perfect desalinization only by soil washing. The grinding method is actually used in the primary desalinization process in order to desalinize radioactivity-contaminated concrete. This method does desalinization by grinding the radioactivity-contaminated area of the concrete surface with desalinization equipment, which enables a near-to-perfect desalinization for relatively thinly contaminated surface. Likewise, this research verified the degree of desalinization by applying the grinding method and comparing it to the fragmentizing-washing method, and attempted to find a method to desalinize uranium-contaminated gravels more effectively. In order to desalinize uranium-contaminated gravels more effectively and compare to the existing washing-desalinization method, we conducted a desalinization experiment with grinding method that grinds gravel surface. As a

Decontamination method of contaminated metals

International Nuclear Information System (INIS)

Kawamura, Fumio; Ueda, Yoshihiro; Sato, Chikara; Komori, Itaru.

1980-01-01

Purpose: To effectively separate radioactive materials from molten metals in dry-processing method by heating metals contaminated with radioactive materials at a temperature below melting point to oxidize the surface thereof, then heating them to melt and include the radioactive materials into the oxides. Method: Metals contaminated with radioactive materials are heated at a temperature below the melting point thereof in an oxidizing atmosphere to oxidize the surface. Thereafter they are heated to melt at temperature above the melting point of the metals, and the molten metals are separated with the radioactive materials included in the oxides. For instance, radiation-contaminated aluminum pipe placed on the bed of an electrical heating furnace, and heated at 500 0 C which is lower than the melting point 660 0 C of aluminum for 1 - 2 hours while supplying air from an air pipe into the furnace, and an oxide film is formed on the surface of the aluminum pipe. Then, the furnace temperature is increased to 750 0 C wherein molten aluminum is flown down to a container and the oxide film is separated by floating it as the slug on the molten aluminum. (Horiuchi, T.)

Radiation protection aspects of the trafficking radionuclides contaminated metal scrap

International Nuclear Information System (INIS)

Prouza, Z.

1999-01-01

This paper covers the legal base of the release in the environment of radionuclides containing materials and the radiation protection aspects of trafficking in radionuclides contaminated materials. Materials, substance and objects containing radionuclides or contaminated by them may be released into the environment, if they do not exceed values authorized by SONS (State Office of Nuclear Safety). Legislative measures should be taken against illicit trafficking of the nuclear material in all the areas. The creation of a sophisticated system for the control and regulation of all important radionuclides released into the environment should be based on the radiation protection limits, constraints, reference and exemption levels which are introduced in the legislative documents; the strong supervision of producers and users of the sealed sources by SONS side, in addition to the requirements of the licensing process of their sources; a complete data-base and information exchange system related to illicit trafficking in contaminated material; in this system all the authorities with jurisdiction should be involved. The responsibilities of the persons involved in metal scrap trafficking should include arrangement of appropriate monitoring, rules for transport of the metal scrap, an adequate measuring system to monitor metal scrap including monitoring to prevent processing or smelting of the radioactive material, control measures, etc. All of the above items of legislation are an important challenge for the Czech Republic. (author)

Morphology and Differentiation of MG63 Osteoblast Cells on Saliva Contaminated Implant Surfaces

Directory of Open Access Journals (Sweden)

Neda Shams

2015-11-01

Full Text Available Objectives: Osteoblasts are the most important cells in the osseointegration process. Despite years of study on dental Implants, limited studies have discussed the effect of saliva on the adhesion process of osteoblasts to implant surfaces. The aim of this in vitro study was to evaluate the effect of saliva on morphology and differentiation of osteoblasts attached to implant surfaces.Materials and Methods: Twelve Axiom dental implants were divided into two groups. Implants of the case group were placed in containers, containing saliva, for 40 minutes. Then, all the implants were separately stored in a medium containing MG63 human osteoblasts for a week. Cell morphology and differentiation were assessed using a scanning electron microscope and their alkaline phosphatase (ALP activity was determined. The t-test was used to compare the two groups.Results: Scanning electron microscopic observation of osteoblasts revealed round or square cells with fewer and shorter cellular processes in saliva contaminated samples, whereas elongated, fusiform and well-defined cell processes were seen in the control group. ALP level was significantly lower in case compared to control group (P<0.05.Conclusion: Saliva contamination alters osteoblast morphology and differentiation and may subsequently interfere with successful osseointegration. Thus, saliva contamination of bone and implant must be prevented or minimized.

Direct-scanning alpha spectrometer for americium and plutonium contamination on highly-enriched uranium surfaces

International Nuclear Information System (INIS)

Ward, W.C.; Martinez, H.E.; Abeyta, C.L.; Morgan, A.N.; Nelson, T.O.

1997-01-01

Trace Pu 239 and Am 241 contamination on a surface whose alpha count is dominated by U 235 and U 234 decay has been successfully quantified by counting swipes in external alpha spectroscopy chambers. The swipe process, however, is labor intensive and subject to uncertainties in the swiping process as well as degraded spectral resolution due to the presence of the swipe material. A multichannel instrument for automated in situ measurements of interior and exterior contamination has been developed which incorporates a rotary table, 13 fixed ion-implanted silicon detectors, and spectroscopy electronics. Custom software was written to allow alpha spectrometer to function as a virtual instrument in the LabView environment. This system gives improved speed and resolution as well as a complete log of the location of areas of high surface contamination, a feature not practical to obtain by other methods, and one which opens the possibility of long term studies such as Pu outgrowth evaluation employing the instrument. The authors present performance data as well as system integration, calibration, control, and dynamic geometric efficiency calculations related to the design of this and next generation systems

Radioactive materials released from nuclear power plants (1976)

International Nuclear Information System (INIS)

Decker, T.R.

1978-11-01

Releases of radioactive materials in airborne and liquid effluents from commercial light water reactors during 1976 have been compiled and reported. Data on solid waste shipments as well as selected operating information have been included. This report supplements earlier annual reports issued by the former Atomic Energy Commission and the Nuclear Regulatory Commission. The 1976 release data are compared with previous year releases in tabular form. Data covering specific radionuclides are summarized

Synthesis of present methods of surface contamination detection (skin, clothes, laboratories)

International Nuclear Information System (INIS)

Joudrier, P.

1983-01-01

The signification of the term ''contamination'' is briefly recalled. To measure the levels of contamination, there are only two methods: the direct method and the indirect method. Finally, the recent improvements in the surface contamination detection field are shortly reviewed [fr

Radioactive materials released from nuclear power plants

International Nuclear Information System (INIS)

Tichler, J.; Norden, K.; Congemi, J.

1991-05-01

Releases of radioactive materials in airborne and liquid effluents from commercial light water reactors during 1988 have been compiled and reported. Data on solid waste shipments as well as selected operating information have been included. This report supplements earlier annual reports issued by the former Atomic Energy Commission and the Nuclear Regulatory Commission. The 1988 release data are summarized in tabular form. Data covering specific radionuclides are summarized. 16 tabs

Ion release from magnesium materials in physiological solutions under different oxygen tensions.

Science.gov (United States)

Feyerabend, Frank; Drücker, Heiko; Laipple, Daniel; Vogt, Carla; Stekker, Michael; Hort, Norbert; Willumeit, Regine

2012-01-01

Although magnesium as degradable biomaterial already showed clinical proof of concepts, the design of new alloys requires predictive in vitro methods, which are still lacking. Incubation under cell culture conditions to obtain "physiological" corrosion may be a solution. The aim of this study was to analyse the influence of different solutions, addition of proteins and of oxygen availability on the corrosion of different magnesium materials (pure Mg, WE43, and E11) with different surface finishing. Oxygen content in solution, pH, osmolality and ion release were determined. Corrosion led to a reduction of oxygen in solution. The influence of oxygen on pH was enhanced by proteins, while osmolality was not influenced. Magnesium ion release was solution-dependent and enhanced in the initial phase by proteins with delayed release of alloying elements. The main corrosion product formed was magnesium carbonate. Therefore, cell culture conditions are proposed as first step toward physiological corrosion.

Hanford Tanks 241-C-203 and 241 C 204: Residual Waste Contaminant Release Model and Supporting Data

Energy Technology Data Exchange (ETDEWEB)

Deutsch, William J.; Krupka, Kenneth M.; Lindberg, Michael J.; Cantrell, Kirk J.; Brown, Christopher F.; Schaef, Herbert T.

2007-05-23

This report was revised in May 2007 to correct 90Sr values in Chapter 3. The changes were made on page 3.9, paragraph two and Table 3.10; page 3.16, last paragraph on the page; and Tables 3.21 and 3.31. The rest of the text remains unchanged from the original report issued in October 2004. This report describes the development of release models for key contaminants that are present in residual sludge remaining after closure of Hanford Tanks 241-C-203 (C-203) and 241-C-204 (C-204). The release models were developed from data generated by laboratory characterization and testing of samples from these two tanks. Key results from this work are (1) future releases from the tanks of the primary contaminants of concern (99Tc and 238U) can be represented by relatively simple solubility relationships between infiltrating water and solid phases containing the contaminants; and (2) high percentages of technetium-99 in the sludges (20 wt% in C-203 and 75 wt% in C-204) are not readily water leachable, and, in fact, are very recalcitrant. This is similar to results found in related studies of sludges from Tank AY-102. These release models are being developed to support the tank closure risk assessments performed by CH2M HILL Hanford Group, Inc., for the U.S. Department of Energy.

Radioactive contamination of nest materials of the Eurasian Tree Sparrow Passer montanus due to the Fukushima nuclear accident: The significance in the first year.

Science.gov (United States)

Matsui, Shin; Kasahara, Satoe; Morimoto, Gen; Mikami, Osamu K; Watanabe, Mamoru; Ueda, Keisuke

2015-11-01

The 2011 Fukushima nuclear accident contaminated large areas of eastern and northeastern Japan, releasing vast amounts of radiation. Here we investigated radioactive contamination of the nest materials of the Eurasian Tree Sparrow Passer montanus from the breeding season of 2011 directly after the accident to the next breeding season of 2012 at two sites. In Tokyo (222 km southwest of the plant), ambient dose rates in the nestboxes were lower than those in Ibaraki (175 km southwest of the plant), where the levels of 2011 were higher than those of 2012. Further, the amount of radioactive Cs in each nest increased with the increase in nest weight, with a higher increment at Ibaraki than at Tokyo. These data suggested higher nest contamination levels in the breeding season directly after a nuclear accident than in later seasons, and an increment of nest contamination levels via nest materials of birds. Copyright © 2015 Elsevier Ltd. All rights reserved.

Studies on release and deposition behaviour of cesium from contaminated sodium pools and cesium trap development for FBTR

International Nuclear Information System (INIS)

Sahoo, P.; Kannan, S.E.; Muralidharan, P.; Chandran, K.

1996-01-01

Investigations were carried out on the release and deposition behaviour of cesium from sodium pools in air-filled chamber in the temperature range of 673 to 873 K, using Cs-134 to simulate Cs-137. About 0.12 kg of sodium was loaded in a burn-pot together with 92.5 kBq of cesium. Experiments were carried out with 21% oxygen. Natural burning period of sodium and specific activity ratio between cesium and sodium showed a tendency to decrease and release fractions of both the species tended to increase with temperature. From the surface deposited aerosols it was observed that cesium has propensity to settle down closer to the point of release. A cesium trap has been developed for FBTR with RVC as getter material. Absorption kinetics and particle release behaviour studies pointed to its intended satisfactory performance in the plant. (author)

E-PERM alpha surface monitor

International Nuclear Information System (INIS)

Fricke, V.

1999-01-01

Innovative Technology Summary Reports are designed to provide potential users with the information they need to quickly determine if a technology would apply to a particular environmental management problem. They are also designed for readers who may recommend that a technology be considered by prospective users. Each report describes a technology, system, or process that has been developed and tested with funding from DOE's Office of Science and Technology (OST). The E-PERMreg s ign Alpha Surface Monitor is an integrating electret ion chamber innovative technology used to measure alpha radiation on surfaces of materials. The technology is best used on surfaces with low contamination levels such as areas with potential for free release, but can also be used in areas with higher levels of contamination. Measurement accuracy and production of the E-PERM reg s ign Alpha Surface Monitor compared favorably with the baseline technology. The innovative technology cost is approximately 28% higher than the baseline with an average unit cost per reading costing %6.04 vs. $4.36; however, the flexibility of the E-PERMreg s ign Alpha Surface Monitor may offer advantages in ALARA, reduction of operator error, waste minimization, and measurement accuracy

Growth factor delivery: How surface interactions modulate release in vitro and in vivo

Science.gov (United States)

King, William J.; Krebsbach, Paul H.

2013-01-01

Biomaterial scaffolds have been extensively used to deliver growth factors to induce new bone formation. The pharmacokinetics of growth factor delivery has been a critical regulator of their clinical success. This review will focus on the surface interactions that control the non-covalent incorporation of growth factors into scaffolds and the mechanisms that control growth factor release from clinically relevant biomaterials. We will focus on the delivery of recombinant human bone morphogenetic protein-2 from materials currently used in the clinical practice, but also suggest how general mechanisms that control growth factor incorporation and release delineated with this growth factor could extend to other systems. A better understanding of the changing mechanisms that control growth factor release during the different stages of preclinical development could instruct the development of future scaffolds for currently untreatable injuries and diseases. PMID:22433783

Decontamination tests on tritium-contaminated materials

International Nuclear Information System (INIS)

Boutot, P.; Schipfer, P.

1967-01-01

These tests are designed to try out various processes liable to be applied to the decontamination of a material contaminated with tritium. The samples are thin stainless- steel slabs contaminated in the laboratory with elements extracted from industrial installations. The measurement of the initial and residual activities is carried out using an open-window BERTHOLD counter. The best results are obtained by passing a current of pre-heated (300 deg. C) air containing water vapour. This process makes it possible to reach a decontamination factor of 99.5 per cent in 4 hours. In a vacuum, the operation has to be prolonged to 100 hours in order to obtain a decontamination factor of 99.2 per cent. Wet-chemical or electrolytic treatments are efficient but their use is limited by the inherent corrosion risks. A study of the reappearance of the contamination has made it possible to observe that this phenomenon occurs whatever the process used. (authors) [fr

Assessment of consequences from airborne releases of radioactive material

International Nuclear Information System (INIS)

McGrath, P.E.; Blond, R.M.

1976-01-01

Over the past several years, the manner in which assessments have been made of the consequences of large airborne releases of radioactive material has not changed much conceptually. The models to describe the atmospheric dispersion of the radioactive material have generally been time-invariant, i.e., the meteorological conditions (thermal stability, wind speed, and precipitation) are invariant during release and the subsequent period of radiation exposure of the population to the airborne material. The frequency distribution of the meteorological conditions are determined by analyzing several years of weather data from the appropriate geographical location. In reality, weather is continuously changing over short time periods (hours) following the release. It is to be expected that the changing meteorological conditions would have important effects on the potential consequences of the release. A time-dependent atmospheric dispersion model was developed and implemented in the Reactor Safety Study. This paper provides a description of the model and the nature of the results generated. Emphasis is given to an explanation of how, and why, these results differ from those estimated with time-invariant models

Influence of factors on release of antimicrobials from antimicrobial packaging materials.

Science.gov (United States)

Wu, Yu-Mei; Wang, Zhi-Wei; Hu, Chang-Ying; Nerín, Cristina

2018-05-03

Antimicrobial packaging materials (films or coatings) (APMs) have aroused great interest among the scientists or the experts specialized in material science, food science, packaging engineering, biology and chemistry. APMs have been used to package the food, such as dairy products, poultry, meat (e.g., beef), salmon muscle, pastry dough, fresh pasta, bakery products, fruits, vegetables and beverages. Some materials have been already commercialized. The ability of APMs to extend the shelf-life of the food depends on the release rate of the antimicrobials (AMs) from the materials to the food. The optimum rate is defined as target release rate (TRR). To achieve TRR, the influencing factors of the release rate should be considered. Herein we reviewed for the first time these factors and their influence on the release. These factors mainly include the AMs, food (or food simulant), packaging materials, the interactions among them, the temperature and environmental relative humidity (RH).

Uranium pollution in an estuary affected by pyrite acid mine drainage and releases of naturally occurring radioactive materials

International Nuclear Information System (INIS)

Villa, M.; Manjon, G.; Hurtado, S.; Garcia-Tenorio, R.

2011-01-01

Highlights: → Huelva estuary is affected by former phosphogypsum releases and pyrite acid mine drainage. → Time evolution of uranium concentration is analyzed after halting of NORM releases. → Two new contamination sources are preventing the complete uranium cleaning: (1) The leaching of phosphogypsum stacks located close to Tinto River. (2) Pyrite acid mine drainage. → High uranium concentrations are dissolved in water and precipitate subsequently. - Abstract: After the termination of phosphogypsum discharges to the Huelva estuary (SW Spain), a unique opportunity was presented to study the response of a contaminated environmental compartment after the cessation of its main source of pollution. The evolution over time of uranium concentrations in the estuary is presented to supply new insights into the decontamination of a scenario affected by Naturally Occurring Radioactive Material (NORM) discharges. The cleaning of uranium isotopes from the area has not taken place as rapidly as expected due to leaching from phosphogypsum stacks. An in-depth study using various techniques of analysis, including 234 U/ 238 U and 230 Th/ 232 Th ratios and the decreasing rates of the uranium concentration, enabled a second source of uranium contamination to be discovered. Increased uranium levels due to acid mine drainage from pyrite mines located in the Iberian Pyrite Belt (SW Spain) prevent complete uranium decontamination and, therefore, result in levels nearly twice those of natural background levels.

GWSCREEN: A semi-analytical model for assessment of the groundwater pathway from surface or buried contamination: Theory and user`s manual

Energy Technology Data Exchange (ETDEWEB)

Rood, A.S.

1992-03-01

GWSCREEN was developed for assessment of the groundwater pathway from leaching of radioactive and non radioactive substances from surface or buried sources. The code was designed for implementation in the Track 1 and Track 2 assessment of Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) sites identified as low probability hazard at the Idaho National Engineering Laboratory (DOE, 1991). The code calculates the limiting soil concentration such that regulatory contaminant levels in groundwater are not exceeded. The code uses a mass conservation approach to model three processes: Contaminant release from a source volume, contaminant transport in the unsaturated zone, and contaminant transport in the saturated zone. The source model considers the sorptive properties and solubility of the contaminant. Transport in the unsaturated zone is described by a plug flow model. Transport in the saturated zone is calculated with a semi-analytical solution to the advection dispersion equation for transient mass flux input.

Review on fluoride-releasing restorative materials--fluoride release and uptake characteristics, antibacterial activity and influence on caries formation.

Science.gov (United States)

Wiegand, Annette; Buchalla, Wolfgang; Attin, Thomas

2007-03-01

The purpose of this article was to review the fluoride release and recharge capabilities, and antibacterial properties, of fluoride-releasing dental restoratives, and discuss the current status concerning the prevention or inhibition of caries development and progression. Information from original scientific full papers or reviews listed in PubMed (search term: fluoride release AND (restorative OR glass-ionomer OR compomer OR polyacid-modified composite resin OR composite OR amalgam)), published from 1980 to 2004, was included in the review. Papers dealing with endodontic or orthodontic topics were not taken into consideration. Clinical studies concerning secondary caries development were only included when performed in split-mouth design with an observation period of at least three years. Fluoride-containing dental materials show clear differences in the fluoride release and uptake characteristics. Short- and long-term fluoride releases from restoratives are related to their matrices, setting mechanisms and fluoride content and depend on several environmental conditions. Fluoride-releasing materials may act as a fluoride reservoir and may increase the fluoride level in saliva, plaque and dental hard tissues. However, clinical studies exhibited conflicting data as to whether or not these materials significantly prevent or inhibit secondary caries and affect the growth of caries-associated bacteria compared to non-fluoridated restoratives. Fluoride release and uptake characteristics depend on the matrices, fillers and fluoride content as well as on the setting mechanisms and environmental conditions of the restoratives. Fluoride-releasing materials, predominantly glass-ionomers and compomers, did show cariostatic properties and may affect bacterial metabolism under simulated cariogenic conditions in vitro. However, it is not proven by prospective clinical studies whether the incidence of secondary caries can be significantly reduced by the fluoride release of

Evaluation of wastewater contaminant transport in surface waters using verified Lagrangian sampling

Science.gov (United States)

Antweiler, Ronald C.; Writer, Jeffrey H.; Murphy, Sheila F.

2014-01-01

Contaminants released from wastewater treatment plants can persist in surface waters for substantial distances. Much research has gone into evaluating the fate and transport of these contaminants, but this work has often assumed constant flow from wastewater treatment plants. However, effluent discharge commonly varies widely over a 24-hour period, and this variation controls contaminant loading and can profoundly influence interpretations of environmental data. We show that methodologies relying on the normalization of downstream data to conservative elements can give spurious results, and should not be used unless it can be verified that the same parcel of water was sampled. Lagrangian sampling, which in theory samples the same water parcel as it moves downstream (the Lagrangian parcel), links hydrologic and chemical transformation processes so that the in-stream fate of wastewater contaminants can be quantitatively evaluated. However, precise Lagrangian sampling is difficult, and small deviations – such as missing the Lagrangian parcel by less than 1 h – can cause large differences in measured concentrations of all dissolved compounds at downstream sites, leading to erroneous conclusions regarding in-stream processes controlling the fate and transport of wastewater contaminants. Therefore, we have developed a method termed “verified Lagrangian” sampling, which can be used to determine if the Lagrangian parcel was actually sampled, and if it was not, a means for correcting the data to reflect the concentrations which would have been obtained had the Lagrangian parcel been sampled. To apply the method, it is necessary to have concentration data for a number of conservative constituents from the upstream, effluent, and downstream sites, along with upstream and effluent concentrations that are constant over the short-term (typically 2–4 h). These corrections can subsequently be applied to all data, including non-conservative constituents. Finally, we

Evaluation of wastewater contaminant transport in surface waters using verified Lagrangian sampling.

Science.gov (United States)

Antweiler, Ronald C; Writer, Jeffrey H; Murphy, Sheila F

2014-02-01

Contaminants released from wastewater treatment plants can persist in surface waters for substantial distances. Much research has gone into evaluating the fate and transport of these contaminants, but this work has often assumed constant flow from wastewater treatment plants. However, effluent discharge commonly varies widely over a 24-hour period, and this variation controls contaminant loading and can profoundly influence interpretations of environmental data. We show that methodologies relying on the normalization of downstream data to conservative elements can give spurious results, and should not be used unless it can be verified that the same parcel of water was sampled. Lagrangian sampling, which in theory samples the same water parcel as it moves downstream (the Lagrangian parcel), links hydrologic and chemical transformation processes so that the in-stream fate of wastewater contaminants can be quantitatively evaluated. However, precise Lagrangian sampling is difficult, and small deviations - such as missing the Lagrangian parcel by less than 1h - can cause large differences in measured concentrations of all dissolved compounds at downstream sites, leading to erroneous conclusions regarding in-stream processes controlling the fate and transport of wastewater contaminants. Therefore, we have developed a method termed "verified Lagrangian" sampling, which can be used to determine if the Lagrangian parcel was actually sampled, and if it was not, a means for correcting the data to reflect the concentrations which would have been obtained had the Lagrangian parcel been sampled. To apply the method, it is necessary to have concentration data for a number of conservative constituents from the upstream, effluent, and downstream sites, along with upstream and effluent concentrations that are constant over the short-term (typically 2-4h). These corrections can subsequently be applied to all data, including non-conservative constituents. Finally, we show how data

Corrective Action Investigation Plan for Corrective Action Unit 166: Storage Yards and Contaminated Materials, Nevada Test Site, Nevada, Rev. No.: 0

Energy Technology Data Exchange (ETDEWEB)

David Strand

2006-06-01

Corrective Action Unit 166 is located in Areas 2, 3, 5, and 18 of the Nevada Test Site, which is 65 miles northwest of Las Vegas, Nevada. Corrective Action Unit (CAU) 166 is comprised of the seven Corrective Action Sites (CASs) listed below: (1) 02-42-01, Cond. Release Storage Yd - North; (2) 02-42-02, Cond. Release Storage Yd - South; (3) 02-99-10, D-38 Storage Area; (4) 03-42-01, Conditional Release Storage Yard; (5) 05-19-02, Contaminated Soil and Drum; (6) 18-01-01, Aboveground Storage Tank; and (7) 18-99-03, Wax Piles/Oil Stain. These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives. Additional information will be obtained by conducting a corrective action investigation (CAI) before evaluating corrective action alternatives and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable corrective action alternatives that will be presented in the Corrective Action Decision Document. The sites will be investigated based on the data quality objectives (DQOs) developed on February 28, 2006, by representatives of the Nevada Division of Environmental Protection; U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office; Stoller-Navarro Joint Venture; and Bechtel Nevada. The DQO process was used to identify and define the type, amount, and quality of data needed to develop and evaluate appropriate corrective actions for CAU 166. Appendix A provides a detailed discussion of the DQO methodology and the DQOs specific to each CAS. The scope of the CAI for CAU 166 includes the following activities: (1) Move surface debris and/or materials, as needed, to facilitate sampling. (2) Conduct radiological surveys. (3) Perform field screening. (4) Collect and submit environmental samples for laboratory analysis to determine if

Laser-induced damage of fused silica at 355 and 1065 nm initiated at aluminum contamination particles on the surface

International Nuclear Information System (INIS)

Genin, F.Y.; Michlitsch, K.; Furr, J.; Kozlowski, M.R.; Krulevitch, P.

1997-01-01

1-μm thick circular dots, 10-250 μm dia, were deposited onto 1.14 cm thick fused silica windows by sputtering Al through a mask. Al shavings were also deposited on the windows to investigate effects of particle-substrate adhesion. The silica windows were then illuminated repetitively using a 3-ns, 355 nm and an 8.6-ns, 1064 nm laser. The tests were conducted at near normal incidence with particles on input and output surfaces of the windows. During the first shot, a plasma ignited at the metal particle and damage initiated on the fused silica surface. The morphology of the damage at the metal dots were reproducible but different for input and output surface contamination. For input surface contamination, minor damage occurred where the particle was located; such damage ceased to grow with the removal of contaminant material. More serious damage (pits and cracks) was initiated on the output surface (especially at 355 nm) and grew to catastrophic proportions after few shots. Output surface contaminants were usually ejected on the initial shot, leaving a wave pattern on the surface. No further damage occurred with subsequent shots unless a shot (usually the first shot) cracked the surface; such behavior was mostly observed at 355 nm and occasionally for large shavings at 1064 nm. The size of the damaged area scaled with the size of the particle (except when catastrophic damage occurred). Onset of catastrophic damage on output surface occurred only when particles exceeded a critical size. Damage behavior of the sputtered dots was found to be qualitatively similar to that of the shavings. The artificial contamination technique accelerated the study by allowing better control of the test conditions

Widespread arsenic contamination of soils in residential areas and public spaces: an emerging regulatory or medical crisis?

Science.gov (United States)

Belluck, D A; Benjamin, S L; Baveye, P; Sampson, J; Johnson, B

2003-01-01

A critical review finds government agencies allow, permit, license, or ignore arsenic releases to surface soils. Release rates are controlled or evaluated using risk-based soil contaminant numerical limits employing standardized risk algorithms, chemical-specific and default input values. United States arsenic residential soil limits, approximately 0.4- approximately 40 ppm, generally correspond to a one-in-one-million to a one-in-ten-thousand incremental cancer risk range via ingestion of or direct contact with contaminated residential soils. Background arsenic surface soil levels often exceed applicable limits. Arsenic releases to surface soils (via, e.g., air emissions, waste recycling, soil amendments, direct pesticide application, and chromated copper arsenic (CCA)-treated wood) can result in greatly elevated arsenic levels, sometimes one to two orders of magnitude greater than applicable numerical limits. CCA-treated wood, a heavily used infrastructure material at residences and public spaces, can release sufficient arsenic to result in surface soil concentrations that exceed numerical limits by one or two orders of magnitude. Although significant exceedence of arsenic surface soil numerical limits would normally result in regulatory actions at industrial or hazardous waste sites, no such pattern is seen at residential and public spaces. Given the current risk assessment paradigm, measured or expected elevated surface soil arsenic levels at residential and public spaces suggest that a regulatory health crisis of sizeable magnitude is imminent. In contrast, available literature and a survey of government agencies conducted for this paper finds no verified cases of human morbidity or mortality resulting from exposure to elevated levels of arsenic in surface soils. This concomitance of an emerging regulatory health crisis in the absence of a medical crisis is arguably partly attributable to inadequate government and private party attention to the issue.

Reactor surface contamination stabilization. Innovative technology summary report

International Nuclear Information System (INIS)

1998-11-01

Contaminated surfaces, such as the face of a nuclear reactor, need to be stabilized (fixed) to avoid airborne contamination during decontamination and decommissioning activities, and to prepare for interim safe storage. The traditional (baseline) method of fixing the contamination has been to spray a coating on the surfaces, but ensuring complete coverage over complex shapes, such as nozzles and hoses, is difficult. The Hanford Site C Reactor Technology Demonstration Group demonstrated innovative technologies to assess stabilization properties of various coatings and to achieve complete coverage of complex surfaces on the reactor face. This demonstration was conducted in two phases: the first phase consisted of a series of laboratory assessments of various stabilization coatings on metal coupons. For the second phase, coatings that passed the laboratory tests were applied to the front face of the C Reactor and evaluated. The baseline coating (Rust-Oleum No. 769) and one of the innovative technologies did not completely cover nozzle assemblies on the reactor face, the most critical of the second-phase evaluation criteria. However, one of the innovative coating systems, consisting of a base layer of foam covered by an outer layer of a polymeric film, was successful. The baseline technology would cost approximately 33% as much as the innovative technology cost of $64,000 to stabilize an entire reactor face (196 m 2 or 2116 ft 2 ) with 2,004 nozzle assemblies, but the baseline system failed to provide complete surface coverage

Control criteria for residual contamination in materials considered for recycle and reuse

International Nuclear Information System (INIS)

Kennedy, W.E. Jr.; Hill, R.L.; Aaberg, R.L.

1993-11-01

Pacific Northwest Laboratory (PNL) is collecting data and conducting technical analyses to support the US Department of Energy (DOE), Office of Environmental Guidance, Air, Water, and Radiation Division (DOE/EH-232) in determining the feasibility of developing radiological control criteria for recycling or reuse of metals or equipment containing residual radioactive contamination from DOE operations. The criteria, framed as acceptable concentrations for release of materials for recycling or reuse, will be risk-based and will be developed through analysis of radiation exposure scenarios and pathways. The analysis will include evaluation of relevant radionuclides, potential mechanisms of exposure, and non-health-related impacts of residual radioactivity on electronics and film. The analyses will consider 42 key radionuclides that are generated during DOE operations and may be contained in recycled or reused metals or equipment