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Sample records for controlling radionuclide releases

  1. Preliminary assessment of the controlled release of radionuclides from waste packages containing borosilicate waste glass

    International Nuclear Information System (INIS)

    Strachan, D.M.; McGrail, B.P.; Apted, M.J.; Engle, D.W.; Eslinger, P.W.

    1990-06-01

    The purpose of this report is to provide a preliminary assessment of the release-rate for an engineered barriers subsystem (EBS) containing waste packages of defense high-level waste borosilicate glass at geochemical and hydrological conditions similar to the those at Yucca Mountain. The relationship between the proposed Waste Acceptance Preliminary Specifications (WAPS) test of glass- dissolution rate and compliance with the NRC's release-rate criterion is also evaluated. Calculations are reported for three hierarchical levels: EBS analysis, waste-package analysis, and waste-glass analysis. The following conclusions identify those factors that most acutely affect the magnitude of, or uncertainty in, release-rate performance

  2. Radionuclide release from research reactor spent fuel

    Energy Technology Data Exchange (ETDEWEB)

    Curtius, H., E-mail: h.curtius@fz-juelich.de [Forschungszentrum Juelich, Institut fuer Energieforschung, IEF-6 Sicherheitsforschung und Reaktortechnik, Geb. 05.3, D-52425 Juelich (Germany); Kaiser, G.; Mueller, E.; Bosbach, D. [Forschungszentrum Juelich, Institut fuer Energieforschung, IEF-6 Sicherheitsforschung und Reaktortechnik, Geb. 05.3, D-52425 Juelich (Germany)

    2011-09-01

    Numerous investigations with respect to LWR fuel under non oxidizing repository relevant conditions were performed. The results obtained indicate slow corrosion rates for the UO{sub 2} fuel matrix. Special fuel-types (mostly dispersed fuels, high enriched in {sup 235}U, cladded with aluminium) are used in German research reactors, whereas in German nuclear power plants, UO{sub 2}-fuel (LWR fuel, enrichment in {sup 235}U up to 5%, zircaloy as cladding) is used. Irradiated research reactor fuels contribute less than 1% to the total waste volume. In Germany, the state is responsible for fuel operation and for fuel back-end options. The institute for energy research (IEF-6) at the Research Center Juelich performs investigation with irradiated research reactor spent fuels under repository relevant conditions. In the study, the corrosion of research reactor spent fuel has been investigated in MgCl{sub 2}-rich salt brine and the radionuclide release fractions have been determined. Leaching experiments in brine with two different research reactor fuel-types were performed in a hot cell facility in order to determine the corrosion behaviour and the radionuclide release fractions. The corrosion of two dispersed research reactor fuel-types (UAl{sub x}-Al and U{sub 3}Si{sub 2}-Al) was studied in 400 mL MgCl{sub 2}-rich salt brine in the presence of Fe{sup 2+} under static and initially anoxic conditions. Within these experimental parameters, both fuel types corroded in the experimental time period of 3.5 years completely, and secondary alteration phases were formed. After complete corrosion of the used research reactor fuel samples, the inventories of Cs and Sr were quantitatively detected in solution. Solution concentrations of Am and Eu were lower than the solubility of Am(OH){sub 3}(s) and Eu(OH){sub 3}(s) solid phases respectively, and may be controlled by sorption processes. Pu concentrations may be controlled by Pu(IV) polymer species, but the presence of Pu(V) and Pu

  3. TURVA-2012: Formulation of radionuclide release scenarios

    International Nuclear Information System (INIS)

    Marcos, Nuria; Hjerpe, Thomas; Snellman, Margit; Ikonen, Ari; Smith, Paul

    2014-01-01

    TURVA-2012 is Posiva's safety case in support of the Preliminary Safety Analysis Report (PSAR) and application for a construction licence for a repository for disposal of spent nuclear fuel at the Olkiluoto site in south-western Finland. This paper gives a summary of the scenarios and the methodology followed in formulating them as described in TURVA-2012: Formulation of Radionuclide Release Scenarios (Posiva, 2013). The scenarios are further analysed in TURVA-2012: Assessment of Radionuclide Release Scenarios for the Repository System and TURVA-2012: Biosphere Assessment (Posiva, 2012a, 2012b). The formulation of scenarios takes into account the safety functions of the main barriers of the repository system and the uncertainties in the features, events, and processes (FEP) that may affect the entire disposal system (i.e. repository system plus the surface environment) from the emplacement of the first canister until the far future. In the report TURVA-2012: Performance Assessment (2012d), the performance of the engineered and natural barriers has been assessed against the loads expected during the evolution of the repository system and the site. Uncertainties have been identified and these are taken into account in the formulation of radionuclide release scenarios. The uncertainties in the FEP and evolution of the surface environment are taken into account in formulating the surface environment scenarios used ultimately in estimating radiation exposure. Formulating radionuclide release scenarios for the repository system links the reports Performance Assessment and Assessment of Radionuclide Release Scenarios for the Repository System. The formulation of radionuclide release scenarios for the surface environment brings together biosphere description and the surface environment FEP and is the link to the assessment of the surface environment scenarios summarised in TURVA-2012: Biosphere Assessment. (authors)

  4. Radionuclide deposition control

    International Nuclear Information System (INIS)

    1980-01-01

    A method is described for controlling the deposition, on to the surfaces of reactor components, of the radionuclides manganese-54, cobalt-58 and cobalt-60 from a liquid stream containing the radionuclides. The method consists of disposing a getter material (nickel) in the liquid stream, and a non-getter material (tantalum, tungsten or molybdenum) as a coating on the surfaces where deposition is not desired. The process is described with special reference to its use in the coolant circuit in sodium cooled fast breeder reactors. (U.K.)

  5. Radionuclide release calculations for SAR-08

    International Nuclear Information System (INIS)

    Thomson, Gavin; Miller, Alex; Smith, Graham; Jackson, Duncan

    2008-04-01

    Following a review by the Swedish regulatory authorities of the post-closure safety assessment of the SFR 1 disposal facility for low and intermediate waste (L/ILW), SAFE, the SKB has prepared an updated assessment called SAR-08. This report describes the radionuclide release calculations that have been undertaken as part of SAR-08. The information, assumptions and data used in the calculations are reported and the results are presented. The calculations address issues raised in the regulatory review, but also take account of new information including revised inventory data. The scenarios considered include the main case of expected behaviour of the system, with variants; low probability releases, and so-called residual scenarios. Apart from these scenario uncertainties, data uncertainties have been examined using a probabilistic approach. Calculations have been made using the AMBER software. This allows all the component features of the assessment model to be included in one place. AMBER has been previously used to reproduce results the corresponding calculations in the SAFE assessment. It is also used in demonstration of the IAEA's near surface disposal assessment methodology ISAM and has been subject to very substantial verification tests and has been used in verifying other assessment codes. Results are presented as a function of time for the release of radionuclides from the near field, and then from the far field into the biosphere. Radiological impacts of the releases are reported elsewhere. Consideration is given to each radionuclide and to each component part of the repository. The releases from the entire repository are also presented. The peak releases rates are, for most scenarios, due to organic C-14. Other radionuclides which contribute to peak release rates include inorganic C-14, Ni-59 and Ni-63. (author)

  6. Radionuclide release calculations for SAR-08

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, Gavin; Miller, Alex; Smith, Graham; Jackson, Duncan (Enviros Consulting Ltd, Wolverhampton (United Kingdom))

    2008-04-15

    Following a review by the Swedish regulatory authorities of the post-closure safety assessment of the SFR 1 disposal facility for low and intermediate waste (L/ILW), SAFE, the SKB has prepared an updated assessment called SAR-08. This report describes the radionuclide release calculations that have been undertaken as part of SAR-08. The information, assumptions and data used in the calculations are reported and the results are presented. The calculations address issues raised in the regulatory review, but also take account of new information including revised inventory data. The scenarios considered include the main case of expected behaviour of the system, with variants; low probability releases, and so-called residual scenarios. Apart from these scenario uncertainties, data uncertainties have been examined using a probabilistic approach. Calculations have been made using the AMBER software. This allows all the component features of the assessment model to be included in one place. AMBER has been previously used to reproduce results the corresponding calculations in the SAFE assessment. It is also used in demonstration of the IAEA's near surface disposal assessment methodology ISAM and has been subject to very substantial verification tests and has been used in verifying other assessment codes. Results are presented as a function of time for the release of radionuclides from the near field, and then from the far field into the biosphere. Radiological impacts of the releases are reported elsewhere. Consideration is given to each radionuclide and to each component part of the repository. The releases from the entire repository are also presented. The peak releases rates are, for most scenarios, due to organic C-14. Other radionuclides which contribute to peak release rates include inorganic C-14, Ni-59 and Ni-63. (author)

  7. Cycle of radionuclides released into waters by the nuclear industry

    International Nuclear Information System (INIS)

    Bovard, A.; Grauby, A.

    1975-01-01

    A review is made of the main radionuclides released by nuclear industry into the aquatic environment. The water-sediment interactions, the uptake of radionuclides by aquatic organisms and the problem of irrigation water are considered [fr

  8. Application of innovative policies for controlling radionuclide releases: The open-quotes open-market trading ruleclose quotes

    International Nuclear Information System (INIS)

    Moeller, D.W.

    1997-01-01

    In the past, most efforts for reducing airborne radio nuclide releases and controlling radioactive wastes have been directed to the development of new and improved technologies. Little attention has been paid to the possible application to these problems of new, innovative policies. Yet, experience in other fields shows that such applications could be beneficial. A prime example is the open-quotes open-market trading rule,close quotes now being widely used in the U.S. for the control of a range of environmental problems. Through this rule, nuclear facility operators would be permitted to control airborne emissions in a more cost-effective manner, and those responsible for decommissioning and decontaminating nuclear facilities no longer in operation could do so at far lower costs while generating significantly smaller volumes of radioactive wastes. Application of such a policy would also significantly reduce the demands on existing, and the need for research to develop new, improved, control technologies. 16 refs

  9. Application of innovative policies for controlling radionuclide releases: The {open_quotes}open-market trading rule{close_quotes}

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, D.W. [Dade Moeller & Associates, Inc., New Bern, NC (United States)

    1997-08-01

    In the past, most efforts for reducing airborne radio nuclide releases and controlling radioactive wastes have been directed to the development of new and improved technologies. Little attention has been paid to the possible application to these problems of new, innovative policies. Yet, experience in other fields shows that such applications could be beneficial. A prime example is the {open_quotes}open-market trading rule,{close_quotes} now being widely used in the U.S. for the control of a range of environmental problems. Through this rule, nuclear facility operators would be permitted to control airborne emissions in a more cost-effective manner, and those responsible for decommissioning and decontaminating nuclear facilities no longer in operation could do so at far lower costs while generating significantly smaller volumes of radioactive wastes. Application of such a policy would also significantly reduce the demands on existing, and the need for research to develop new, improved, control technologies. 16 refs.

  10. Effects of sorption hysteresis on radionuclide releases from waste packages

    International Nuclear Information System (INIS)

    Barney, G.S.; Reed, D.T.

    1985-01-01

    A one-dimensional, numerical transport model was used to calculate radionuclide releases from waste packages emplaced in a nuclear waste repository in basalt. The model incorporates both sorption and desorption isotherm parameters measured previously for sorption of key radionuclides on the packing material component of the waste package. Sorption hysteresis as described by these isotherms lowered releases of some radionuclides by as much as two orders of magnitude. Radionuclides that have low molar inventories (relative to uranium), high solubility, and strongly sorbed, are most affected by sorption hysteresis. In these cases, almost the entire radionuclide inventory is sorbed on the packing material. The model can be used to help optimize the thickness of the packing material layer by comparing release rate versus packing material thickness curves with Nuclear Regulatory Commission (NRC) and Environmental Protection Agency (EPA) release limits

  11. Biological implications of radionuclides released from nuclear industries

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1979-08-15

    The development of nuclear power technologies has led to a rapid increase in the number of reactors and other installations including fuel reprocessing and radioactive waste treatment plants in operation. Associated with these developments are the concomitant possibilities for release of radionuclides in the environment, which in turn might exert some biological impacts including late somatic and genetic effects on man. The principal objective of the Agency's symposium was, therefore, to review critically the current information on the biological effects of exposure to low levels of incorporated radionuclides and the radiation doses absorbed from them. The purpose of this review was to provide a sound scientific basis on which to evaluate radiation safety standards, risk-benefit analysis, as well as the regulatory control and management of nuclear wastes. The major part of the discussions centered around the problems of the radiobiology, radio-oncology, radio-ecology and toxicology of the transuranic such as such as plutonium, americium, curium as well as radionuclide species like tritium, krypton and iodine among others, which are expected to be released from these nuclear installations. Current data and practical information obtained through suitably designed animal studies and also from epidemiological, ecological and food-chain analyses and other relevant follow-up surveys of late effects in accidentally exposed occupational personnel were reported for discussion and risk evaluation.

  12. Radionuclide releases from natural analogues of spent nuclear fuel

    International Nuclear Information System (INIS)

    Curtis, D.B.; Fabryka-Martin, J.; Dixon, P.; Aguilar, R.; Rokop, D.; Cramer, J.

    1993-01-01

    Measures of 99 Tc, 129 I, 239 Pu and U concentrations in rock samples from uranium deposits at Cigar Lake and Koongarra have been used to study processes of radionuclide release from uranium minerals. Rates of release have been immeasurably slow at Cigar Lake. At Koongarra release rates appear to have been faster, producing small deficiencies of 99 Tc, and larger ones of 129 I. The inferred differences in radionuclide release rates are consistent with expected differences in uranium mineral degradation rates produced by the differing hydrogeochemical environments at the two sites

  13. CRRIS, Health Risk Assessment from Atmospheric Releases of Radionuclides

    International Nuclear Information System (INIS)

    1999-01-01

    1 - Description of program or function: CRRIS consists of eight fully integrated computer codes which calculate environmental transport of atmospheric releases of radionuclides and resulting doses and health risks to individuals or populations. Each code may be used alone for various assessment applications. Because of its modular structure, CRRIS allows assessments to be tailored to the user's needs. Radionuclides are handled by CRRIS either in terms of the released radionuclides or the exposure radionuclides which consist of both the released nuclides and decay products that build up during environmental transport. Atmospheric dispersion calculations are performed by the ANEMOS computer code for distances less than 100 km and the RETADD-II computer code regional-scale distances. Both codes estimate annual-average air concentrations and ground deposition rates by location. SUMIT will translate and scale multiple ANEMOS runs onto a master grid. TERRA reads radionuclide air concentrations and deposition rates to estimate concentrations of radionuclides in food and surface soil. Radiologic decay and ingrowth, soil leaching, and transport through the food chain are included in the calculations. MLSOIL computes an effective radionuclide ground-surface concentration to be used in computing external health effects. The five-layer model of radionuclide transport through soil in MLSOIL provides an alternative to the single-layer model used in TERRA. DFSOIL computes dose factors used in MLSOIL to compute doses from the five soil layers and from the ground surface. ANDROS reads environmental concentrations of radionuclides computed by the other CRRIS codes and produces tables of doses and risks to individuals or populations from atmospheric releases of radionuclides. 2 - Method of solution: SUMIT performs geometric interpolation. TERRA and MLSOIL are terrestrial transport compartment models. DFSOIL computes soil-layer-specific dose factors based on the point-kernel method

  14. Building shielding effects on radiation doses from routine radionuclide releases

    International Nuclear Information System (INIS)

    Kocher, D.C.

    1977-01-01

    In calculating population doses from the release of radionuclides to the atmosphere, it is usually assumed that man spends all of his time outdoors standing on a smooth infinite plane. Realistically, however, man spends most of the time indoors, so that substantial reductions in radiation doses may result compared with the usual estimates. Calculational models were developed to study the effects of building structures on radiation doses from routine releases of radionuclides to the atmosphere. Both internal dose from inhaled radionuclides and external photon dose from airborne and surface-deposited radionuclides are considered. The effect of building structures is described quantitatively by a dose reduction factor, which is the ratio of the dose inside a structure to the corresponding dose with no structure present. The internal dose from inhaled radionuclides is proportional to the radionuclide concentration in the air. Assuming that the outdoor airborne concentration is constant with time, the time-dependence of the indoor airborne concentration in terms of the structure air ventilation rate, the deposition velocities for radionuclides on the inside floor, walls, and ceiling, and the radioactive decay constant, were calculated

  15. Assessment of Radionuclides Release from Inshas LILW Disposal Facility Under Normal and Unusual Operational Conditions

    International Nuclear Information System (INIS)

    Zaki, A.A.

    2008-01-01

    Disposing of low and intermediate radioactive waste (LILW) is a big concern for Egypt due to the accumulated waste as a result of past fifty years of peaceful nuclear applications. Assessment of radionuclides release from Inshas LILW disposal facility under normal and unusual operational conditions is very important in order to apply for operation license of the facility. Aqueous release of radionuclides from this disposal facility is controlled by water flow, access of the water to the wasteform, release of the radionuclides from the wasteform, and transport to the disposal facility boundary. In this work, the release of 137 Cs , 6C o, and 90 Sr radionuclides from the Inshas disposal facility was studied under the change of operational conditions. The release of these radio contaminants from the source term to the unsaturated and saturated zones , to groundwater were studied. It was found that the concentration of radionuclides in a groundwater well located 150 m away from the Inshas disposal facility is less than the maximum permissible concentration in groundwater in both cases

  16. Microbial transformations of radionuclides released from nuclear fuel reprocessing plants

    International Nuclear Information System (INIS)

    Francis, A.J.

    2007-01-01

    Microorganisms can affect the stability and mobility of the actinides U, Pu, Cm, Am, Np, and the fission products Tc, I, Cs, Sr, released from nuclear fuel reprocessing plants. Under appropriate conditions, microorganisms can alter the chemical speciation, solubility and sorption properties and thus could increase or decrease the concentrations of radionuclides in solution and the bioavailability. Dissolution or immobilization of radionuclides is brought about by direct enzymatic action or indirect non-enzymatic action of microorganisms. Although the physical, chemical, and geochemical processes affecting dissolution, precipitation, and mobilization of radionuclides have been investigated, we have only limited information on the effects of microbial processes. The mechanisms of microbial transformations of the major and minor actinides and the fission products under aerobic and anaerobic conditions in the presence of electron donors and acceptors are reviewed. (author)

  17. Radionuclides release possibility analysis of MSR at various accident conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Choong Wie; Kim, Hee Reyoung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    There are some accidents which go beyond our expectation such as Fukushima Daiichi nuclear disaster and amounts of radionuclides release to environment, so more effort and research are conducted to prevent it. MSR (Molten Salt Reactor) is one of GEN-IV reactor types, and its coolant and fuel are mixtures of molten salt. MSR has a schematic like figure 1 and it has different features with the solid fuel reactor, but most important and interesting feature of MSR is its many safety systems. For example, MSR has a large negative void coefficient. Even though power increases, the reactor slows down soon. Radionuclides release possibility of MSR was analyzed at various accident conditions including Chernobyl and Fukushima ones. The MSR was understood to prevent the severe accident by the negative reactivity coefficient and the absence of explosive material such as water at the Chernobyl disaster condition. It was expected to contain fuel salts in the reactor building and not to release radionuclides into environment even if the primary system could be ruptured or broken and fuel salts would be leaked at the Fukushima Daiichi nuclear disaster condition of earthquake and tsunami. The MSR, which would not lead to the severe accident and therefore prevents the fuel release to the environment at many expected scenarios, was thought to have priority in the aspect of accidents. A quantitative analysis and a further research are needed to evaluate the possibility of radionuclide release to the environment at the various accident conditions based on the simple comparison of the safety feature between MSR and solid fuel reactor.

  18. Radionuclide release rates from spent fuel for performance assessment modeling

    International Nuclear Information System (INIS)

    Curtis, D.B.

    1994-01-01

    In a scenario of aqueous transport from a high-level radioactive waste repository, the concentration of radionuclides in water in contact with the waste constitutes the source term for transport models, and as such represents a fundamental component of all performance assessment models. Many laboratory experiments have been done to characterize release rates and understand processes influencing radionuclide release rates from irradiated nuclear fuel. Natural analogues of these waste forms have been studied to obtain information regarding the long-term stability of potential waste forms in complex natural systems. This information from diverse sources must be brought together to develop and defend methods used to define source terms for performance assessment models. In this manuscript examples of measures of radionuclide release rates from spent nuclear fuel or analogues of nuclear fuel are presented. Each example represents a very different approach to obtaining a numerical measure and each has its limitations. There is no way to obtain an unambiguous measure of this or any parameter used in performance assessment codes for evaluating the effects of processes operative over many millennia. The examples are intended to suggest by example that in the absence of the ability to evaluate accuracy and precision, consistency of a broadly based set of data can be used as circumstantial evidence to defend the choice of parameters used in performance assessments

  19. Radionuclide release from low-level waste in field lysimeters

    International Nuclear Information System (INIS)

    Oblath, S.B.

    1986-01-01

    A field program has been in operation for 8 years at the Savannah River Plant (SRP) to determine the leaching/migration behavior of low-level radioactive waste using lysimeters. The lysimeters are soil-filled caissons containing well characterized wastes, with each lysimeter serving as a model of a shallow land burial trench. Sampling and analysis of percolate water and vegetation from the lysimeters provide a determination of the release rates of the radionuclides from the waste/soil system. Vegetative uptake appears to be a major pathway for migration. Fractional release rates from the waste/soil system are less than 0.01% per year. Waste-to-soil leach rates up to 10% per year have been determined by coring several of the lysimeters. The leaching of solidified wasteforms under unsaturated field conditions has agreed well with static, immersion leaching of the same type waste in the laboratory. However, releases from the waste/soil system in the lysimeter may be greater than predicted based on leaching alone, due to complexation of the radionuclides by other components leached from the wastes to form mobile, anionic species

  20. Natural radionuclides in effluents release by a deactivated uranium mine

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Wagner S.; Kelecom, Alphonse; Silva, Ademir X.; Lopes, José M.; Pinto, Carlos E.C.; Py Júnior, Delcy A.; Antunes, Marcos M., E-mail: pereiraws@gmail.com, E-mail: caerjbr@gmail.com, E-mail: wspereira@inb.gov.br, E-mail: delcy@inb.gov.br, E-mail: Antunes@inb.gov.br, E-mail: lararapls@hotmail.com, E-mail: Ademir@nuclear.ufrj.br, E-mail: marqueslopes@yahoo.com.br [Universidade Veiga de Almeida (UVA), Rio de Janeiro, RJ (Brazil); Indústrias Nucleares do Brasil (COMAP.N/FCN/INB), Resende RJ (Brazil). Fábrica de Combustível Nuclear. Coordenação de Meio Ambiente e Proteção Radiológica Ambiental; Universidade Federal Fluminense (LARARA-PLS/UFF), Niterói, RJ (Brazil). Laboratório de Radiobiologia e Radiometria; Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear

    2017-07-01

    The Ore Treatment Unit (OTU) is a mine and deactivated uranium plant in the city of Caldas, Minas Gerais, Brazil. This facility possesses three points of release of liquid effluents containing radionuclides: point 014, 025 and 076. At these points, the values of activity concentrations (AC) of the radionuclides U{sub nat}, {sup 226}Ra, {sup 210}Pb, {sup 232}Th and {sup 228}Ra were analyzed in 2012. The evaluation of point 014 by univariate statistics pointed four groups. [U{sub nat} > {sup 228}Ra > ({sup 226}Ra = {sup 210}Pb) >{sup 232}Th]. The multivariate statistics separated the radionuclides into two groups: [(U{sub nat} and {sup 232}Th) and ({sup 226}Ra, {sup 228}Ra and {sup 210}Pb)]. At point 025, the univariate statistics described three groups: [Un{sub at} > ({sup 228}Ra = {sup 210}Pb) > ({sup 226}Ra = {sup 232}Th)] and the multivariate analysis also described three but different groups: [(U{sub nat} and {sup 228}Ra), ({sup 226}Ra and {sup 210}Pb) and {sup 232}Th]. In turn, point 076 showed another behavior. The univariate analysis showed only two groups: [(U{sub nat}) > ({sup 226}Ra, {sup 228}Ra, {sup 210}Pb, {sup 232}Th)]. Differently, the multivariate statistics defined three groups: [(U{sub nat} and {sup 232}Th), ({sup 226}Ra and {sup 228}Ra) and {sup 210}Pb].Thus, statistical analysis showed that each point has releases of effluents with different characteristics. Both the behaviors of releases, based on multivariate statistics, and of the AC magnitudes, based on the univariate statistics, are different between the points. The only common features were the greater magnitude of uranium and the smaller magnitude of thorium. (author)

  1. Dose assessment on natural radiation, natural radionuclide, and artificial radionuclide released by Fukushima nuclear accident

    International Nuclear Information System (INIS)

    Hosoda, Masahiro; Tokonami, Shinji; Furukawa, Masahide

    2012-01-01

    Various radionuclides are distributed in environmental materials such as soil, rock, and water. People are exposed every day to natural radiation. According to the UNSCEAR 2008 report, Sources of Ionizing Radiation, natural radiation sources are categorized as terrestrial gamma-rays, radon, cosmic rays and food. The effective dose from radon, thoron and its decay products is about 50% of all natural radiation exposure. Consciousness of the Japanese public toward radiation exposure has significantly increased since the start of the Fukushima Dai-ichi Nuclear Power Station accident. In this paper, the nationwide survey and dose estimation for terrestrial gamma-rays and radon are summarized. External dose from artificial radionuclides released by the Fukushima accident are also reported. (author)

  2. The impacts of radionuclide releases into the marine environment

    International Nuclear Information System (INIS)

    1981-01-01

    The impact of radiation on the marine environment has been of interest to the international community since the advent of nuclear fission. This interest continues with the increasing industrial use of nuclear power and the associated need for the disposal of nuclear waste. Continued dumping of low-level waste into the sea and direct discharge of liquid effluents into coastal waters, as well as potential radionuclide additions to the deep ocean from other sources, dictates that the possible long-term effects on the seas must be closely watched. By means of field studies in contaminated environments, our knowledge of long-lived radionuclides, especially the transuranium elements, is increasing. We are far from the goal, however, of being able to predict the behaviour of these elements in the marine environment, particularly in the deep sea. We know even less about other long-lived radionuclides such as technetium, whose inventory may be as high as 170 000 kg by the year 2000 according to some projections. Clearly, attempts to unravel the behaviour and fate of these long-lived radionuclides introduced into the sea will present a challenge to the environmental scientist during the next decade. In addition, the new philosophy of the International Commission on Radiological Protection (ICRP) as set out in Publication No.26, emphasizes justification and optimization both in the release of radioactive effluents into the sea and in the sea-dumping of radioactive solid wastes. To satisfy the demands of this new philosophy requires a broader range of environmental information than has previously been available. The papers assembled for this symposium represent an authoritative account of the subject's global status in 1980. The object of the meeting was to review the origins, measurements, behaviour, fate and impacts of artificial radioactive additions to the marine environment

  3. Health risks from radionuclides released into the Clinch River

    International Nuclear Information System (INIS)

    Thomas, B.A.; Hoffman, F.O.; Miller, L.F.

    1999-01-01

    The purpose of this work is to estimate off-site radiation doses and health risks (with uncertainties) associated with the release of radionuclides from the X-10 site. Following an initial screening analysis, the exposure pathways of interest included fish ingestion, drinking water ingestion, the ingestion of milk and meat, and external exposure from shoreline sediment. Four representative locations along the Clinch River, from the White Oak Creek Embayment to the city of Kingston, were chosen. The demography of the lower Clinch River supplied information dealing with land use that aided in the determination of sites on which to focus efforts. The locations that proved to be the most significant included Jones Island at Clinch River Mile (CRM) 20.5, Grassy Creek and K-25 (CRM 14), Kingston Steam Plant (CRM 3.5), and the city of Kingston (CRM 0). These areas of interest have historically been and are still primarily agricultural and residential areas. Reference individuals were determined with respect to the pathways involved. The primary radionuclides of interest released from the X-10 facility into the Clinch River via White Oak Creek were identified in the initial screening analysis as 137 Cs, 90 Sr, 60 Co, 106 Ru, 144 Ce, 131 I, 95 Zr, and 95 Nb. Of these radionuclides, 137 Cs, 60 Co, 106 Ru, 90 Sr, 144 Ce, 95 Zr, and 95 Nb were evaluated for their contribution to the external exposure pathway. This study utilized an object-oriented modeling software package that provides an alternative to the spreadsheet, providing graphical influence diagrams to show qualitative structure of models, hierarchical models to organize complicated models into manageable modules, and intelligent arrays with the power to scale up simple models to handle large problems. The doses and risks estimated in this study are not significant enough to cause a detectable increase in health effects in the population. In most cases, the organ does are well below the limits of epidemiological

  4. Atmospheric dispersion of radionuclides released by a nuclear plant

    International Nuclear Information System (INIS)

    Barboza, A.A.

    1989-01-01

    A numerical model has been developed to simulate the atmospheric dispersion of radionuclides released by a nuclear plant operating under normal conditions. The model, based on gaussian plume representation, accouts for and evaluates several factors which affect the concentraction of effluents in the atmosphere, such as: ressuspension, deposition, radioactive decay, energy and type of the radiation emitted, among others. The concentraction of effluents in the atmosphere is calculated for a uniform mesh of points around the plant, allowing the equivalent doses to be then evaluated. Simulations of the atmosphere dispersion of radioactive plumes of Cs 137 and Ar 41 have been performed assuming a constant rate of release, as expected from the normal operation of a nuclear plant. Finally, this work analyzes the equivalent doses at ground level due to the dispersion of Cs 137 and Ar 41 , accumulated over one year and determines the isodose curves for a hypothetical site. (author) [pt

  5. Individual radiation doses from unit releases of long lived radionuclides

    International Nuclear Information System (INIS)

    Bergstroem, U.; Nordlinder, S.

    1990-04-01

    The turn-over in a standard biosphere of radionuclides, disposed in a repository for high level waste was studied from a dose point of view. A multi-compartment model with unit releases to the biosphere was designed and solved by the BIOPATH-code. The uncertainty in the results due to the uncertainty in input parameter values were examined for all nuclides with the PRISM-system. Adults and five year old children were exposed from 10 different exposure pathways originating from activity in well and lake water. The results given as total doses per year and Bq release (conversion factors) can be used in combination with leakage rates from the geosphere for safety analysis of a repository. The conversion factors obtained (arithmetic mean values), are given. (65 refs.) (authors)

  6. Health impacts of large releases of radionuclides. Proceedings

    International Nuclear Information System (INIS)

    Lake, J.V.; Bock, G.R.; Cardew, Gail

    1997-01-01

    There have been various large-scale releases of radionuclides into the environment in the 20th century. Some of these have been accidental and some deliberate. In order to minimize the risk to human health of such releases, it is important that we understand how these substances are transported throughout the terrestrial and aquatic environments and the ways in which they can ultimately affect human health. This book contains contributions from the world's leading radioecologists and health scientists who discuss the progress in understanding these transport processes and exposure pathways of radionuclides to humans; the problems and latest techniques of quantitating retrospectively the actual doses received by individuals; the time course of effects of exposure in relation to structure and function at the cellular tissue, organ and whole organism level; the genetic effects, and effects on reproductive health, in populations and individuals, including fetal effects in pregnant women and inherited genetic effects; and scientific approaches to evaluate the important problem of the mental health consequences of perceived risk of radiation damage to health. (author)

  7. Radionuclides and isotopes release of spent fuel matrix. Conceptual and mathematical models of wastes behaviour

    International Nuclear Information System (INIS)

    Cera, E.; Merino, J.; Bruno, J.

    2000-01-01

    We have developed a conceptual and numerical model to calculate release of selected radionuclides from spent fuel under repository condition. This has been done in the framework of the Enresa 2000 performance assessment exercise. The model has been developed based on kinetic mass balance equations in order to study the evolution of the spent fuel water interface as a function of time. Several processes have been kinetically modelled: congruent dissolution, radioactive decay, ingrowth and water turnover in the gap. The precipitation/redissolution of secondary solid phases has been taken into account from a thermodynamic point of view. Both approaches have been coupled and the resulting equations solved for a number of radionuclides in both, a conservative and realistic approach. The results show three distinct groups of radionuclides based on their release behaviour: a first group is composed of radioisotopes of highly insoluble elements (e. g., Pu, Am, Pd) whose concentration in the gap is mainly controlled by their solubility and therefore their evolution is identical in both cases. Secondly, a set of radionuclides from soluble elements under these conditions (e. g., I, Cs, Ra) show concentrations kinetically controlled, decreasing with time following the congruent dissolution trend. Their release concentrations are one order of magnitude larger in the conservative case than in the realistic case. Finally, a third group has been identified (e. g., Se, Th, Cm) where a mixed behaviour takes place: initially their solubility limiting phases control their concentration in the gap but the situation reverts to a kinetic control as the chemical conditions change and the secondary precipitates become totally dissolved. The fluxes of the different radionuclides are also given as an assessment of the source term in the performance assessment. (Author)

  8. Haw-glass dissolution and radionuclide release: mechanism - modelling - source term

    Energy Technology Data Exchange (ETDEWEB)

    Grambow, B [Forschungszentrum Karlsruhe, Institut fur Nukleare, Karlsruhe (Germany)

    1997-07-01

    Important release controlling processes are: 1) kinetics of glass matrix dissolution (leaching), 2) formation of secondary alteration products (controlling thermodynamic solubility), 3) sorption on surfaces in the engineered barrier system and 4) formation of mobile species. Quantification of these processes requires assessment of the energetics and dynamics of the various reversible and irreversible processes within an overall open non-equilibrium system. Corrosion/dissolution of the waste matrices is not necessarily associated with a proportional release of radionuclides. The formation of new secondary phases, such as silicates, molybdates, uranates, carbonates... establishes a new geochemical barrier for re-immobilization of radionuclides dissolved from the waste matrices. The presence of iron (corroding canisters during glass alteration) reduces the solution concentration of redox sensitive radionuclides. Consequently, the container, after being corroded, constitutes an important geochemical barrier for radionuclide re-immobilization. Geochemical modelling of the long-term behaviour of glasses must be performed in an integrated way, considering simultaneous reactions of the glass, of container corrosion, of repository rock and of backfill material. Until now, only few attempts were made for integral systems modelling. (A.C.)

  9. Natural radionuclides in effluents release by a deactivated uranium mine

    International Nuclear Information System (INIS)

    Pereira, Wagner S.; Kelecom, Alphonse; Silva, Ademir X.; Lopes, José M.; Pinto, Carlos E.C.; Py Júnior, Delcy A.; Antunes, Marcos M.; Indústrias Nucleares do Brasil; Universidade Federal Fluminense; Coordenacao de Pos-Graduacao e Pesquisa de Engenharia

    2017-01-01

    The Ore Treatment Unit (OTU) is a mine and deactivated uranium plant in the city of Caldas, Minas Gerais, Brazil. This facility possesses three points of release of liquid effluents containing radionuclides: point 014, 025 and 076. At these points, the values of activity concentrations (AC) of the radionuclides U_n_a_t, "2"2"6Ra, "2"1"0Pb, "2"3"2Th and "2"2"8Ra were analyzed in 2012. The evaluation of point 014 by univariate statistics pointed four groups. [U_n_a_t > "2"2"8Ra > ("2"2"6Ra = "2"1"0Pb) >"2"3"2Th]. The multivariate statistics separated the radionuclides into two groups: [(U_n_a_t and "2"3"2Th) and ("2"2"6Ra, "2"2"8Ra and "2"1"0Pb)]. At point 025, the univariate statistics described three groups: [Un_a_t > ("2"2"8Ra = "2"1"0Pb) > ("2"2"6Ra = "2"3"2Th)] and the multivariate analysis also described three but different groups: [(U_n_a_t and "2"2"8Ra), ("2"2"6Ra and "2"1"0Pb) and "2"3"2Th]. In turn, point 076 showed another behavior. The univariate analysis showed only two groups: [(U_n_a_t) > ("2"2"6Ra, "2"2"8Ra, "2"1"0Pb, "2"3"2Th)]. Differently, the multivariate statistics defined three groups: [(U_n_a_t and "2"3"2Th), ("2"2"6Ra and "2"2"8Ra) and "2"1"0Pb].Thus, statistical analysis showed that each point has releases of effluents with different characteristics. Both the behaviors of releases, based on multivariate statistics, and of the AC magnitudes, based on the univariate statistics, are different between the points. The only common features were the greater magnitude of uranium and the smaller magnitude of thorium. (author)

  10. Radionuclide solubility control by solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, F.; Klinkenberg, M.; Rozov, K.; Bosbach, D. [Forschungszentrum Juelich GmbH (Germany). Inst. of Energy and Climate Research - Nuclear Waste Management and Reactor Safety (IEK-6); Vinograd, V. [Frankfurt Univ. (Germany). Inst. of Geosciences

    2015-07-01

    The migration of radionuclides in the geosphere is to a large extend controlled by sorption processes onto minerals and colloids. On a molecular level, sorption phenomena involve surface complexation, ion exchange as well as solid solution formation. The formation of solid solutions leads to the structural incorporation of radionuclides in a host structure. Such solid solutions are ubiquitous in natural systems - most minerals in nature are atomistic mixtures of elements rather than pure compounds because their formation leads to a thermodynamically more stable situation compared to the formation of pure compounds. However, due to a lack of reliable data for the expected scenario at close-to equilibrium conditions, solid solution systems have so far not been considered in long-term safety assessments for nuclear waste repositories. In recent years, various solid-solution aqueous solution systems have been studied. Here we present state-of-the art results regarding the formation of (Ra,Ba)SO{sub 4} solid solutions. In some scenarios describing a waste repository system for spent nuclear fuel in crystalline rocks {sup 226}Ra dominates the radiological impact to the environment associated with the potential release of radionuclides from the repository in the future. The solubility of Ra in equilibrium with (Ra,Ba)SO{sub 4} is much lower than the one calculated with RaSO{sub 4} as solubility limiting phase. Especially, the available literature data for the interaction parameter W{sub BaRa}, which describes the non-ideality of the solid solution, vary by about one order of magnitude (Zhu, 2004; Curti et al., 2010). The final {sup 226}Ra concentration in this system is extremely sensitive to the amount of barite, the difference in the solubility products of the end-member phases, and the degree of non-ideality of the solid solution phase. Here, we have enhanced the fundamental understanding regarding (1) the thermodynamics of (Ra,Ba)SO{sub 4} solid solutions and (2) the

  11. Accidental releases of radionuclides: a preliminary study of the consequences of land contamination

    International Nuclear Information System (INIS)

    Simmonds, J.R.; Haywood, S.M.; Linsley, G.S.

    1982-10-01

    The long term consequences of land contamination from accidental releases of activity from thermal reactors are examined. The radiological consequences are assessed using an analysis of the exposure of individuals and the population to ground deposits of the radionuclides released. The contribution of the different nuclides in the release by their various exposure routes to the irradiation of man are calculated as a function of time after release and the most radiologically important are identified. A preliminary assessment is made of off-site economic and social consequences of accidental releases by estimating the areas of land which would be affected by the introduction of countermeasures to control individual radiation exposure due to external irradiation from ground deposits (relocation of populations), and the intake of radionuclides contained in locally produced foodstuffs (restrictions on food production). The areas where administrative controls would be necessary decline in size with time after the release; estimates are made of this time-dependent behaviour using dynamic environmental transfer models. Finally, the collective doses saved by the introduction of countermeasures are estimated using population and agricultural distribution data for a rural location in the United Kingdom. (author)

  12. ASSESSMENT OF RELEASE RATES FOR RADIONUCLIDES IN ACTIVATED CONCRETE.

    Energy Technology Data Exchange (ETDEWEB)

    SULLIVAN,T.M.

    2003-08-23

    The Maine Yankee (MY) nuclear power plant is undergoing the process of decontamination and decommissioning (D&D). Part of the process requires analyses that demonstrate that any radioactivity that remains after D&D will not cause exposure to radioactive contaminants to exceed acceptable limits. This requires knowledge of the distribution of radionuclides in the remaining material and their potential release mechanisms from the material to the contacting groundwater. In this study the concern involves radionuclide contamination in activated concrete in the ICI Sump below the containment building. Figures 1-3 are schematic representations of the ICI Sump. Figure 2 and 3 contain the relevant dimensions needed for the analysis. The key features of Figures 2 and 3 are the 3/8-inch carbon steel liner that isolates the activated concrete from the pit and the concrete wall, which is between 7 feet and 7 feet 2 inches thick. During operations, a small neutron flux from the reactor activated the carbon steel liner and the concrete outside the liner. Current MY plans call for filling the ICI sump with compacted sand.

  13. Ecological reconcentrations of radionuclides released by nuclear industry

    International Nuclear Information System (INIS)

    Schaeffer, R.

    1977-01-01

    An attempt is made to assess the relative importance of the various pathways to man by relating the doses that in the most unfavorable conditions might result from long-term environmental accumulation of the radionuclides to the doses resulting from air inhalation or water ingestion only. For instance, for 131 I released in air, the ratio may reach a value of 1,000 from milk consumption and 3 from consumption of leafy vegetables. For 137 Cs released in water, the ratio may reach a value of 20 from the food chain contamination and 500 on account of external exposure from sediments. However, in spite of these high ratios, the absolute values of the total doses received remain low since the exposures corresponding to air inhalation or water ingestion are usually unsignificant. For water releases, attention is called on the misinterpretations that might result from generalizing the concentration factor values reported in the literature on account of their variations both in time and space: this factor ought to be calculated for each point of the environment on the basis of hydrological data [fr

  14. Environmental risks due to radionuclide releases Environmental Risks Due To Radionuclide Releases From The Oil And Gas Industry

    International Nuclear Information System (INIS)

    Steinhausler, F.

    2005-01-01

    Full text : Exploration and transport in the oil- and gas industry result in the release of elevated levels of natural radioactivity into the environment. This has the following impact: Due to the large volumes of water needed during the extraction of gas and oil the resulting waste water can contain increased concentration of natural radionuclides, such as radium (Ra 226) and its decay products; At the oil/water interface waste water and sludge precipitate and form scalings, containing elevated levels of radium (Ra 226); At oil- and gas extraction sites tanks and equipment can be coated with long-lived radon (Rn 222) decay products; Along oil- and gas pipelines (e.g., at compressor stations) radon (Rn 222) decay products can be deposited internally on metal surfaces, such as valves. Typical U 238-series concentration values in production water range from 8 to 42 kBq/ m3, respectively in scale from 1 to 1 000 kBq/kg. In addition, oil- and gas extraction results in significant releases of natural radionuclides to the atmosphere (Rn 222) and to the water (Th 228, Ra 226, Rn 222, Pb 210, Po 210); for example, about 0.15 GBq/a of Rn 222 are released to the atmosphere per 106 m3 of oil extracted. The disposal of large amounts of contaminated wastes (scales, sludges) represents an environmental problem for the scrap metal industry (recycling of steel pipes containing scales) and the housing industry (use of sludge for landfill below a residential area). Using data from the oil- and gas industry in Latin America, Europe and the Asia-Pacific region, the various exposure pathways are reviewed. Furthermore, the current efforts in defining a suitable regulatory framework are discussed

  15. Introduction to CRRIS: a computerized radiological risk investigation system for assessing atmospheric releases of radionuclides

    International Nuclear Information System (INIS)

    Baes, C.F. III; Miller, C.W.; Kocher, D.C.; Sjoreen, A.L.; Murphy, B.D.

    1985-08-01

    The CRRIS is a Computerized Radiological Risk Investigation System consisting of eight fully integrated computer codes which calculate environmental transport of atmospheric releases of radionuclides and resulting doses and health risks to individuals or populations. Each code may also be used alone for various assessment applications. Radionuclides are handled by the CRRIS either in terms of the released radionuclides or the exposure radionuclides which consist of both the released nuclides and decay products that grow in during environmental transport. The CRRIS is not designed to simulate short-term effects. 51 refs

  16. Radionuclide releases to the Columbia River from Hanford Operations, 1944--1971

    International Nuclear Information System (INIS)

    Heeb, C.M.; Bates, D.J.

    1994-05-01

    The purpose of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation dose that individuals could have received as a result of radionuclide emissions since 1944 from the Hanford Site. One source of radionuclide releases to the Columbia River was from production reactor operations. This report provides a quantitative estimate of the amount of radioactivity released each month (1944--1971) to the Columbia River from eleven radionuclides as well as from gross beta activity

  17. Radionuclide release from PWR spent fuel specimens with induced cladding defects

    International Nuclear Information System (INIS)

    Wilson, C.N.; Oversby, V.M.

    1984-03-01

    Radionuclide releases from pressurized water reactor (PWR) spent fuel rod specimens containing various artificially induced cladding defects were compared by leach testing. The study was conducted in support of the Nevada Nuclear Waste Storage Investigations (NNWSI) Waste Package Task to evaluate the effectiveness of failed cladding as a barrier to radionuclide release. Test description and results are presented

  18. Radionuclide release from PWR spent fuel specimens with induced cladding defects

    International Nuclear Information System (INIS)

    Wilson, C.N.; Oversby, V.M.

    1984-03-01

    Radionuclide releases from pressurized water reactor (PWR) spent fuel rod specimens containing various artificially induced cladding defects were compared by leach testing. The study was conducted in support of the Nevada Nuclear Waste Storage Investigations (NNWSI) Waste Package Task to evaluate the effectiveness of failed cladding as a barrier to radionuclide release. Test description and results are presented. 6 references, 4 figures

  19. Radionuclide releases to the atmosphere from Hanford Operations, 1944--1972. Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Heeb, C.M.

    1994-05-01

    The purpose of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation dose that individuals could have received as a result of radionuclide emissions since 1944 from the Hanford Site. The first step in determining dose is to estimate the amount and timing of radionuclide releases to air and water. This report provides the air release information.

  20. Radionuclide release calculations for selected severe accident scenarios

    International Nuclear Information System (INIS)

    Denning, R.S.; Leonard, M.T.; Cybulskis, P.; Lee, K.W.; Kelly, R.F.; Jordan, H.; Schumacher, P.M.; Curtis, L.A.

    1990-08-01

    This report provides the results of source term calculations that were performed in support of the NUREG-1150 study. ''Severe Accident Risks: An Assessment for Five US Nuclear Power Plants.'' This is the sixth volume of a series of reports. It supplements results presented in the earlier volumes. Analyses were performed for three of the NUREG-1150 plants: Peach Bottom, a Mark I, boiling water reactor; Surry, a subatmospheric containment, pressurized water reactor; and Sequoyah, an ice condenser containment, pressurized water reactor. Complete source term results are presented for the following sequences: short term station blackout with failure of the ADS system in the Peach Bottom plant; station blackout with a pump seal LOCA for the Surry plant; station blackout with a pump seal LOCA in the Sequoyah plant; and a very small break with loss of ECC and spray recirculation in the Sequoyah plant. In addition, some partial analyses were performed which did not require running all of the modules of the Source Term Code Package. A series of MARCH3 analyses were performed for the Surry and Sequoyah plants to evaluate the effects of alternative emergency operating procedures involving primary and secondary depressurization on the progress of the accident. Only thermal-hydraulic results are provided for these analyses. In addition, three accident sequences were analyzed for the Surry plant for accident-induced failure of steam generator tubes. In these analyses, only the transport of radionuclides within the primary system and failed steam generator were examined. The release of radionuclides to the environment is presented for the phase of the accident preceding vessel meltthrough. 17 refs., 176 figs., 113 tabs

  1. Database construction for assessment of chronic radionuclide releases

    International Nuclear Information System (INIS)

    Hively, L.M.; Sjoreen, A.L.; Bledsoe, J.L.

    1986-01-01

    Oak Ridge National Laboratory (ORNL) has developed a comprehensive dose/risk assessment methodology, CRRIS (Computerized Radiological Risk Investigation System), for assessment of atmospheric radionuclide releases (e.g., during decontamination and decommissioning). Radiological effects are calculated for direct atmospheric and ground exposure and for consumption of contaminated agricultural products. Previously, population and agricultural data for CRRIS were tabulated on 1/2-degree square grid cells. This coarse resolution resulted in anomalies such as population in water bodies, agricultural production in city centers, and nonconservation of population over the assessment grid. An even finer mesh (2-minute square grid) is inadequate in densely populated cities where 20,000 or more people live in a square block. These difficulties are overcome by a higher resolution technique using US Census Bureau population data at the most detailed [enumeration district (ED)] level available and by excluding population from unpopulated areas (e.g., water bodies). Agricultural data are available at only the county level and are apportioned to the ED grid according to farm population, conserving the original data. This paper discusses the database construction using Tennessee as an illustration. 10 refs., 2 figs., 1 tab

  2. Radionuclides release to three rivers by ore treatment unit at Caldas, Minas Gerais - Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, W.S.; Carmo, R.F. do; Py Junior, D.A., E-mail: pereiraws@gmail.com [Industrias Nucleares do Brasil (INB), Pocos de Caldas, MG (Brazil). Unidade de Tratamento de Minerio. Grupo Multidisciplinar de Radioprotecao; Kelecom, A., E-mail: akelecom@id.uff.br [Universidade Federal Fluminense (LARARA-PLS/GETA/UFF), Niteroi, RJ (Brazil). Laboratorio de Radiobiologia e Radiometria Pedro Lopes dos Santos. Grupo de Estudos em Temas Ambientais; Pereira, J.R.S., E-mail: pereirarsj@gmail.com [Universidade Federal de Alfenas (UNIFAL), Pocos de Caldas, MG (Brazil)

    2013-07-01

    The Ore Treatment Unit (OTU) is a uranium mining and milling plant, situated at Caldas city, Minas Gerais, Brazil that was disabled in the mid 90's. This unit releases controlled effluents to three rivers: Ribeirao das Antas (at point 014, influenced by the waste pile), Ribeirao Soberbo (point 025, influenced by the waste pond) and Corrego da Consulta (at point 076, influenced by the open pit mine). Water samples collected at these points were analyzed for U{sub nat}, {sup 226}Ra, {sup 210}Pb, {sup 232}Th and {sup 228}Ra content in the particulate and soluble fractions, and the behavior of radionuclide releases and their fractions was investigated. U{sub nat} and {sup 228}Ra showed identical behaviors at these three points. U{sub nat} at point 014 (waste pile) behaved different from described in recent literature data. The isotopes of Ra should exhibit the same behavior at each point, but this was not observed at point 025 (waste pond). {sup 232}Th release showed equal activity concentration near the waste pile (point 014) and near the waste pond (point 025), whilst near the open pit mine (point 076) the soluble fraction showed a concentration of activity greater than the particulate fraction. Finally, {sup 210}Pb showed a different behavior at each point. Due to the great differences in behaviors of each radionuclide, it was not possible to establish a temporal pattern of release which requires assessment over a longer period of time. (author)

  3. Radionuclides release to three rivers by ore treatment unit at Caldas, Minas Gerais - Brazil

    International Nuclear Information System (INIS)

    Pereira, W.S.; Carmo, R.F. do; Py Junior, D.A.

    2013-01-01

    The Ore Treatment Unit (OTU) is a uranium mining and milling plant, situated at Caldas city, Minas Gerais, Brazil that was disabled in the mid 90's. This unit releases controlled effluents to three rivers: Ribeirao das Antas (at point 014, influenced by the waste pile), Ribeirao Soberbo (point 025, influenced by the waste pond) and Corrego da Consulta (at point 076, influenced by the open pit mine). Water samples collected at these points were analyzed for U nat , 226 Ra, 210 Pb, 232 Th and 228 Ra content in the particulate and soluble fractions, and the behavior of radionuclide releases and their fractions was investigated. U nat and 228 Ra showed identical behaviors at these three points. U nat at point 014 (waste pile) behaved different from described in recent literature data. The isotopes of Ra should exhibit the same behavior at each point, but this was not observed at point 025 (waste pond). 232 Th release showed equal activity concentration near the waste pile (point 014) and near the waste pond (point 025), whilst near the open pit mine (point 076) the soluble fraction showed a concentration of activity greater than the particulate fraction. Finally, 210 Pb showed a different behavior at each point. Due to the great differences in behaviors of each radionuclide, it was not possible to establish a temporal pattern of release which requires assessment over a longer period of time. (author)

  4. Sensitivity analysis of biospheric behaviour of radionuclides released from nuclear waste repositories

    International Nuclear Information System (INIS)

    Korhonen, R.; Savolainen, I.; Suolanen, V.

    1985-01-01

    Sensitivity studies of biospheric behaviour of radionuclides released from a planned spent nuclear fuel repository are performed. Sensitivity of radionuclide concentrations in biosphere and that of radiation doses to solubility of nuclides, to sedimentation rate and to intercompartmental water exchange are studied. Solubility has pronounced effect on the sedimentation on the local scale, and in general, sediment sinks were found to be of major importance in the biospheric behaviour of radionuclides. (author)

  5. Impacts of uranium-utilization improvements on light-water-reactor radionuclide releases

    International Nuclear Information System (INIS)

    Aaberg, R.L.

    1981-08-01

    This report discusses potential changes to radionuclide releases as a result of uranium-saving plant modifications and altered operating practices. Only releases to the environment from routine operation are considered; releases resulting from abnormal conditions outside the technical specifications covering plant operation are not considered

  6. 21 CFR 892.5700 - Remote controlled radionuclide applicator system.

    Science.gov (United States)

    2010-04-01

    ... radionuclide applicator system. (a) Identification. A remote controlled radionuclide applicator system is an... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Remote controlled radionuclide applicator system... include patient and equipment supports, component parts, treatment planning computer programs, and...

  7. Radionuclide Release after LBLOCA with Loss of Class IV Power Accident in CANDU-6 Plant

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hoon [KHNP Central Research Institute, Daejeon (Korea, Republic of)

    2011-10-15

    A large break in a pipe train of a primary heat transport system discharges coolant, which has high energy and large mass, into the containment building. Reactor shutdown and emergency core cooling water will limit the fuel cladding failure, but cannot prevent it entirely. The containment building is the last barrier of radionuclide release to the environment. Containment isolation and pressure suppression by dousing and local air cooler reduce the amount of radionuclide release to the environment. The objective of containment behavior analysis for large break loss of coolant with loss of class IV power accident is to assess the amount of radionuclide release to the ambient atmosphere. Radionuclide release rates in this event, with all safety system available, that is, the containment building is intact, as well as with containment system impairment, are analyzed with GOTHIC and SMART code

  8. Assessment of permissible low-level releases of radionuclides into the marine environment

    International Nuclear Information System (INIS)

    Kryshev, I.I.; Sazykina, T.G.

    2002-01-01

    The subject of this paper is radio-ecological assessment of permissible low-level releases of radionuclides in sea waters ensuring the radiological protection of the human population, as well as marine biota. (author)

  9. The fast multiple-path NUCTRAN model -- Calculating the radionuclide release from a repository

    International Nuclear Information System (INIS)

    Romero, L.; Moreno, L.; Neretnieks, I.

    1995-01-01

    The NUCTRAN model has been applied to the Swedish KBS-3 nuclear waste repository concept, where the migration of radionuclides is through various barriers and pathways. The escape of the nuclides from the canister occurs through a small hole. This hole controls the release of nuclides from the repository. NUCTRAN is a useful tool to calculate the nonstationary transport in a repository for high-level nuclear waste. The advantage of this model is the use of a coarse compartmentalization of the repository, which makes it flexible and easy to adapt to different geometries. The several radionuclide release calculations made with NUCTRAN have shown the capability of this to handle different situations rapidly and easily. The particularity of these calculations is the high accuracy obtained by using a coarse compartmentalization of the Swedish KBS-3 repository and the small requirements of computing time. At short times for short-lived nuclides, the calculated releases are exaggerated. The error can be considerably reduced by an additional subdivision of large compartments into a few compartments

  10. Nuclear decay data for radionuclides occurring in routine releases from nuclear fuel cycle facilities

    Energy Technology Data Exchange (ETDEWEB)

    Kocher, D.C.

    1977-08-01

    This report gives tabulations of the atomic and nuclear radiations emitted by 240 radionuclides. Most of the radionuclides are those expected to occur in routine releases of effluents from nuclear fuel cycle facilities. For each radionuclide are given the half-life and recommended values for the energies, intensities, and equilibrium absorbed-dose constants for each of the atomic and nuclear radiations. Also given are the daughter radionuclides produced and recommended values for decay branching ratios, where applicable. The radioactivity decay chains and branching ratios are displayed in diagram form.

  11. Nuclear decay data for radionuclides occurring in routine releases from nuclear fuel cycle facilities

    International Nuclear Information System (INIS)

    Kocher, D.C.

    1977-08-01

    This report gives tabulations of the atomic and nuclear radiations emitted by 240 radionuclides. Most of the radionuclides are those expected to occur in routine releases of effluents from nuclear fuel cycle facilities. For each radionuclide are given the half-life and recommended values for the energies, intensities, and equilibrium absorbed-dose constants for each of the atomic and nuclear radiations. Also given are the daughter radionuclides produced and recommended values for decay branching ratios, where applicable. The radioactivity decay chains and branching ratios are displayed in diagram form

  12. Regulatory Technology Development Plan - Sodium Fast Reactor. Mechanistic Source Term - Metal Fuel Radionuclide Release

    International Nuclear Information System (INIS)

    Grabaskas, David; Bucknor, Matthew; Jerden, James

    2016-01-01

    The development of an accurate and defensible mechanistic source term will be vital for the future licensing efforts of metal fuel, pool-type sodium fast reactors. To assist in the creation of a comprehensive mechanistic source term, the current effort sought to estimate the release fraction of radionuclides from metal fuel pins to the primary sodium coolant during fuel pin failures at a variety of temperature conditions. These release estimates were based on the findings of an extensive literature search, which reviewed past experimentation and reactor fuel damage accidents. Data sources for each radionuclide of interest were reviewed to establish release fractions, along with possible release dependencies, and the corresponding uncertainty levels. Although the current knowledge base is substantial, and radionuclide release fractions were established for the elements deemed important for the determination of offsite consequences following a reactor accident, gaps were found pertaining to several radionuclides. First, there is uncertainty regarding the transport behavior of several radionuclides (iodine, barium, strontium, tellurium, and europium) during metal fuel irradiation to high burnup levels. The migration of these radionuclides within the fuel matrix and bond sodium region can greatly affect their release during pin failure incidents. Post-irradiation examination of existing high burnup metal fuel can likely resolve this knowledge gap. Second, data regarding the radionuclide release from molten high burnup metal fuel in sodium is sparse, which makes the assessment of radionuclide release from fuel melting accidents at high fuel burnup levels difficult. This gap could be addressed through fuel melting experimentation with samples from the existing high burnup metal fuel inventory.

  13. Regulatory Technology Development Plan - Sodium Fast Reactor. Mechanistic Source Term - Metal Fuel Radionuclide Release

    Energy Technology Data Exchange (ETDEWEB)

    Grabaskas, David [Argonne National Lab. (ANL), Argonne, IL (United States); Bucknor, Matthew [Argonne National Lab. (ANL), Argonne, IL (United States); Jerden, James [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-02-01

    The development of an accurate and defensible mechanistic source term will be vital for the future licensing efforts of metal fuel, pool-type sodium fast reactors. To assist in the creation of a comprehensive mechanistic source term, the current effort sought to estimate the release fraction of radionuclides from metal fuel pins to the primary sodium coolant during fuel pin failures at a variety of temperature conditions. These release estimates were based on the findings of an extensive literature search, which reviewed past experimentation and reactor fuel damage accidents. Data sources for each radionuclide of interest were reviewed to establish release fractions, along with possible release dependencies, and the corresponding uncertainty levels. Although the current knowledge base is substantial, and radionuclide release fractions were established for the elements deemed important for the determination of offsite consequences following a reactor accident, gaps were found pertaining to several radionuclides. First, there is uncertainty regarding the transport behavior of several radionuclides (iodine, barium, strontium, tellurium, and europium) during metal fuel irradiation to high burnup levels. The migration of these radionuclides within the fuel matrix and bond sodium region can greatly affect their release during pin failure incidents. Post-irradiation examination of existing high burnup metal fuel can likely resolve this knowledge gap. Second, data regarding the radionuclide release from molten high burnup metal fuel in sodium is sparse, which makes the assessment of radionuclide release from fuel melting accidents at high fuel burnup levels difficult. This gap could be addressed through fuel melting experimentation with samples from the existing high burnup metal fuel inventory.

  14. Modeling of container failure and radionuclide release from a geologic nuclear waste repository

    International Nuclear Information System (INIS)

    Kim, Chang Lak; Kim, Jhin Wung; Choi, Kwang Sub; Cho, Chan Hee

    1989-02-01

    Generally, two processes are involved in leaching and dissolution; (1) chemical reactions and (2) mass transfer by diffusion. The chemical reaction controls the dissolution rates only during the early stage of exposure to groundwater. The exterior-field mass transfer may control the long-term dissolution rates from the waste solid in a geologic repository. Masstransfer analyses rely on detailed and careful application of the governing equations that describe the mechanistic processes of transport of material between and within phases. We develop analytical models to predict the radionuclide release rate into the groundwater with five different approaches: a measurement-based model, a diffusion model, a kinetics model, a diffusion-and-kinetics model, and a modified diffusion model. We also collected experimental leaching data for a partial validation of the radionuclide release model based on the mass transfer theory. Among various types of corrosions, pitting is the most significant because of its rapid growth. The failure time of the waste container, which also can be interpreted as the containment time, is a milestone of the performance of a repository. We develop analytical models to predict the pit growth rate on the container surface with three different approaches: an experimental method, a statistical method, and a mathematical method based on the diffusion theory. (Author)

  15. Forecast of radionuclides release from actual waste form geometries

    International Nuclear Information System (INIS)

    Suarez, A.A.; Rzyski, B.M.; Sato, I.M.

    1989-01-01

    The complete understanding of the leaching mechanism of radionuclides from solid comentitious waste forms is still far from being reached. Much effort has been devoted, however, to identifying and explaining the main components which contribute to the dispersal of radionuclides out of the waste form to the environment. This is of prime importance when short term results are extrapolated into the future. The diffusion coefficient evaluation, based on experimental leaching data obtained from samples produced from the same batch was performed using the exact diffusion formulation applied to real geometric sample shape. This paper discusses the evaluation

  16. CRRIS: a methodology for assessing the impact of airborne radionuclide releases

    International Nuclear Information System (INIS)

    Baes, C.F. III; Miller, C.W.

    1983-01-01

    The Computerized Radiological Risk Investigation System (CRRIS) consists of six fully integrated computer codes which calculate environmental transport and resulting doses and risks to individuals or populations exposed to atmospheric radionuclide releases. The individual codes may be used alone for various assessment applications or may be run as a system. This presentation provides an overview and introduction to this system of computer codes and their use in conducting nuclear assessments. Radionuclides are handled by CRRIS either in terms of the released radionuclides or in terms of exposure radionuclides which consist of both the released nuclides and all (or a subset of) the decay daughters that grow in during environmental transport. The capability of CRRIS to handle radionuclide chains is accomplished through PRIMUS which serves as a preprocessor by accessing a library of radionuclide decay data and sets up matricies of decay constants which are used by the other CRRIS codes in all calculations involving transport and decay. PRIMUS may also be run independently by the user to define the decay chains, radionuclide decay constants, and branching ratios

  17. Spectrometric control of radionuclides production parameters

    International Nuclear Information System (INIS)

    Zhuk, I.; Potarenko, A.; Yarochevich, O.; Hluboky, N.; Kerko, P.; Bogdanov, V.; Dyatel, N.

    2006-01-01

    Full text: A radioactive preparations and sources are widely used all over the world for scientific, industrial and medical purposes. These preparations in Belarus are planned to produce by the Joint Belarussian-Russian Closed Joint Stock Company 'Isotope technologies' (CJSC IT). The company was created in 1998 by two leading scientific centers-SSI 'Joint Institute of Power and Nuclear Research-Sosny' the National Academy of Sciences of Belarus and the State Center of Science of the Russian Federation 'Scientific research institute of nuclear reactors'. One of the mainstream directions in CJSC IT activities is production of radioactive preparations for the industrial and scientific application (such as 133 Ba, 109 Cd, 63 Ni, 60 Co) and for the medical purposes (such as 19 '2Ir, 60 Co). All radioactive preparations have a good export potential and adequate to modern technical and consumer requirements. X-γ spectrometric analysis of considered radioactive sources is one of the basic methods for quality control of radioactive sources. At present, we are developing x-γ spectrometric support of purification process from contaminating radionuclides of 109 Cd -γ preparation and 63 Ni - β preparation. Work on x-γ spectrometric quality control of 133 Ba preparation is carried out. The description of the used equipment is given. Techniques of contaminating radionuclides determination (contents ∼10 - '6 from activity of the basic radionuclide) are presented. Problems of the choice of geometry of measurements of sources with activity about 10 7 -10 9 Bq and possible sources of errors are discussed. (author)

  18. Derived release limits for radionuclides in airborne and liquid effluents for the Whiteshell Nuclear Research Establishment and errata

    International Nuclear Information System (INIS)

    Lemire, A.E.

    1989-08-01

    Radionuclides released to the environment may cause external and internal radiation exposure to man via a number of potential pathways. The resulting radiation dose due to such releases from any operating facility must be kept below dose limits specified in the regulations issued by the Atomic Energy Control Board of Canada. At the Whiteshell Nuclear Research Establishment (WNRE), there is one primary source of liquid effluent to the Winnipeg River via the process water outfall. There are five sources of gaseous effluents: the WR-1 stack; the incinerator stack in the waste management area; the active laboratories building (including the hot cells); the Active-Liquid Waste Treatment Centre; and the compactor-baler in the Waste Management Area. This report presents the methodology and models used to calculate the maximum permissible release rates of radionuclides for each of these sources

  19. Fate of major radionuclides in the liquid wastes released to coastal waters

    International Nuclear Information System (INIS)

    Bhat, I.S.; Verma, P.C.; Iyer, R.S.; Chandramouli, S.

    1980-01-01

    131 I, 134 Cs, 137 Cs and 60 Co have been reported as the major radionuclides in the low level liquid wastes released to coastal waters from atomic power stations. Silt absorption and desorption of the radionuclides were investigated. The exchangeability of the silt absorbed radionuclides and its dependence on particle size were also studied. More than 80% instantaneous absorpt;.on of 60 Co by suspended silt and less than 5% exchangeability of absorbed 60 Co were observed. Biological uptake of the radionuclides by the marine organisms present in sea waters was studied to evaluate radiation exposure pathways. A few benthic and crustacean organisms wnich are consumed by coastal population as fresh sea food, were observed to concentrate the radionuclides to a greater extent than other organisms. (H.K.)

  20. Binding and release of artificial radionuclides in sediments

    International Nuclear Information System (INIS)

    Foerstner, U.; Schoer, J.

    1980-01-01

    Artificial radionuclides in aquatic systems are generally associated with more labile solid phases than are their stable counterparts. This implies that special attention must be paid to the possible effects on the biological uptake of artificial isotopes from contamined dredged materials following deposition or land application. An estimation of possible effects could be made from chemical extraction experiments similar to those already applied to stable heavy metal isotopes. Within the aquatic system the changes of the physico-chemical conditions, such as pH-values, oxygen content, salinity, and the concentration of complexing organic substances, may effect a partial remobilization of artificial radionuclides from the solids, which occurs more readily than with the respective stable isotopes. (orig.) [de

  1. Development of a mechanistic model for release of radionuclides from spent fuel in brines: Salt Repository Project

    International Nuclear Information System (INIS)

    Reimus, P.W.; Windisch, C.F.

    1988-03-01

    At present there are no comprehensive mechanistic models describing the release of radionuclides from spent fuel in brine environments. This report provides a comprehensive review of the various factors that can affect radionuclide release from spent fuel, suggests a modeling approach, and discusses proposed experiments for obtaining a better mechanistic understanding of the radionuclide release processes. Factors affecting radionuclide release include the amount, location, and disposition of radionuclides in the fuel and environmental factors such as redox potential, pH, the presence of complexing anions, temperature, and radiolysis. It is concluded that a model describing the release of radionuclides from spent fuel should contain separate terms for release from the gap, grain boundaries, and grains of the fuel. Possible functional forms for these terms are discussed in the report. Experiments for assessing their validity and obtaining key model parameters are proposed. 71 refs., 4 figs., 6 tabs

  2. Effects of Containment on Radionuclide Releases from Underground Nuclear Explosions

    Science.gov (United States)

    Carrigan, C. R.; Sun, Y.

    2016-12-01

    Confirming the occurrence of an underground nuclear explosion can require capturing short-lived noble gas radioisotopes produced by the explosion, sometimes referred to as the "smoking gun" for nuclear explosion detection. It is well known that the radioisotopic distribution resulting from the detonation evolves with time in the explosion cavity. In effect, the explosion cavity or chimney behaves as a chemical reactor. As long as the parent and daughter radionuclides remain in a closed and well-mixed cavity, parameters, such as radioxenon isotopic ratios, can be calculated analytically from a decay-chain network model. When gases from the cavity migrate into the containment regime, consideration of a "leaky reactor" model is more appropriate. We consider several implications of such a leaky reactor model relevant to interpretations of gas samples from the subsurface during an on-site inspection that could potentially be carried out under the Comprehensive Nuclear Test Ban Treaty. Additionally, we have attempted to validate our leaky reactor model against atmospheric observations of radioactive xenon isotopes detected by radionuclide monitoring stations in Japan and Russia following the February 2013 DPRK underground nuclear explosion (Carrigan et al., 2016). While both model uncertainty and observational error are significant, our model of isotopic evolution appears to be in broad agreement with radionuclide observations, and for the first time links atmospheric measurements of radioxenon isotopic ratios to estimates of seismic yield. Carrigan et al., Scientific Reports 6, Article number: 23032 (2016) doi:10.1038/srep23032

  3. Guidelines for agricultural countermeasures following an accidental release of radionuclides

    International Nuclear Information System (INIS)

    1994-01-01

    The Chernobyl accident in 1986 caused significant radioactive contamination of the environment over widely separated areas, some relatively remote from the site. Considerable scientific research was stimulated directly and indirectly and a good deal of practical experience was obtained in dealing with the aftermath. The collation of the relevant information and experience concerning the transfer of radionuclides through food chains and ways of reducing this transfer is a prudent insurance for the management of agriculture should a major nuclear accident occur again. Work to this end was begun in 1990 by a consultants group convened in a co-ordinated research programme of the IAEA and the CEC on the Validation of Models for the Transfer of Radionuclides in Terrestrial, Urban and Aquatic Environments (VAMP). The work was further developed by a joint programme of the IAEA Division of Nuclear Safety and the Agrochemicals and Residues Section of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture entitled ''Alleviating the Adverse Effects of Excessive Radionuclide Contamination of the Agricultural Environment''. The present Guidelines are an output of this programme and are intended to assist those charged with administrative, scientific and advisory responsibilities to prepare more detail plans specific to the local conditions. 80 refs, 1 fig., 20 tabs

  4. Effects of building structures on radiation doses from routine releases of radionuclides to the atmosphere

    International Nuclear Information System (INIS)

    Kocher, D.C.

    1978-01-01

    Realistic assessments of radiation doses to the population from routine releases of radionuclides to the atmosphere require consideration of man's largely indoor environment. The effect of a building structure on radiation doses is described quantitatively by a dose reduction factor, which is the ratio of the dose to a reference individual inside a structure to the corresponding dose with no structure present. We have implemented models to estimate dose reduction factors for internal dose from inhaled radionuclides and for external photon dose from airborne and surface-deposited radionuclides. The models are particularly useful in radiological assessment applications, since dose reduction factors may readily be estimated for arbitrary mixtures and concentrations of radionuclides in the atmosphere and on the ground. The model for inhalation dose reduction factors accounts for radioactive decay, air ventilation into and out of the structure, and deposition of radionuclides on inside surfaces of the structure. External dose reduction factors are estimated using the point-kernel integration method including consideration of buildup in air and the walls of the building. The potential importance of deposition of radionuclides on inside surfaces of a structure on both inhalation and external dose reduction factors has been demonstrated. Model formulation and the assumptions used in the calculations are discussed. Results of model-parameter sensitivity studies and estimates of dose reduction factors for radionuclides occurring in routine releases from an LWR fuel reprocessing plant are presented. (author)

  5. Radionuclide release from spent fuel under geologic disposal conditions: An overview of experimental and theoretical work through 1985

    Energy Technology Data Exchange (ETDEWEB)

    Reimus, P.W.; Simonson, S.A.

    1988-04-01

    This report presents an overview of experimental and theoretical work on radionuclide release from spent fuel and uranium dioxide (UO/sub 2/) under geologic disposal conditions. The purpose of the report is to provide a source book of information that can be used to develop models that describe radionuclide release from spent fuel waste packages. Modeling activities of this nature will be conducted within the Waste Package Program (WPP) of the Department of Energy's Salt Repository Project (SRP). The topics discussed include experimental methods for investigating radionuclide release, how results have been reported from radionuclide release experiments, theoretical studies of UO/sub 2/ and actinide solubility, results of experimental studies of radionuclide release from spent fuel and UO/sub 2/ (i.e., the effects of different variables on radionuclide release), characteristics of spent fuel pertinent to radionuclide release, and status of modeling of radionuclide release from spent fuel. Appendix A presents tables of data from spent fuel radionuclide release experiments. These data have been digitized from graphs that appear in the literature. An annotated bibliography of literature on spent fuel characterization is provided in Appendix B.

  6. Decision analysis of countermeasures for the milk pathway after an accidental release of radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Ammann, M.; Sinkko, K.; Kostiainen, E.; Salo, E.; Liskola, K.; Haemaelaeinen, R.P.; Mustajoki, J

    2001-12-01

    A facilitated workshop was arranged to plan countermeasures that could reduce the dose arising from the consumption of radionuclide-contaminated milk products. It was assumed that a hypothetical accident in a nuclear facility had led to the release of considerable amounts of radionuclides, which subsequently spread across one of Finland's most important agricultural regions and contaminated the milk produced there. The participants in the workshop, interest groups on food issues, considered all the factors influencing the countermeasure decision, not only radiological or monetary ones but less tangible psychosocial effects as well. The participants preferred the countermeasures provision of uncontaminated fodder and production control to banning and disposal. The analysis showed that these countermeasures could be implemented even if the radionuclide concentrations in foodstuffs were below internationally recommended intervention levels. Banning and withdrawal of milk products from sale was not a favourable option, because of the high costs and disadvantages to producers and the industry, and because the disposal of enormous amounts of milk causes a considerable environmental problem. The study revealed the need to further develop methods to realistically assess the radiological and cost implications of food countermeasures. The feasibility and constraints of actions also need further investigation. The experience gained strongly supports the format of a facilitated workshop to tackle a decision problem that concerns different stakeholders. The participants considered the workshop and the decision analysis very useful in exercises. They also expected a similar approach to be applicable in a real situation, although the suitability was not rated as high as for exercises. It is concluded that a facilitated workshop is a valuable instrument for emergency management and in exercises, when revising emergency plans or in order to identify issues that need to be

  7. Risk-informed assessment of radionuclide release from dissolution of spent nuclear fuel and high-level waste glass

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Tae M., E-mail: tae.ahn@nrc.gov

    2017-06-15

    Highlights: • Dissolution of HLW waste form was assessed with long-term risk informed approach. • The radionuclide release rate decreases with time from the initial release rate. • Fast release radionuclides can be dispersed with discrete container failure time. • Fast release radionuclides can be restricted by container opening area. • Dissolved radionuclides may be further sequestered by sorption or others means. - Abstract: This paper aims to detail the different parameters to be considered for use in an assessment of radionuclide release. The dissolution of spent nuclear fuel and high-level nuclear waste glass was considered for risk and performance insights in a generic disposal system for more than 100,000 years. The probabilistic performance assessment includes the waste form, container, geology, and hydrology. Based on the author’s previous extended work and data from the literature, this paper presents more detailed specific cases of (1) the time dependence of radionuclide release, (2) radionuclide release coupled with container failure (rate-limiting process), (3) radionuclide release through the opening area of the container and cladding, and (4) sequestration of radionuclides in the near field after container failure. These cases are better understood for risk and performance insights. The dissolved amount of waste form is not linear with time but is higher at first. The radionuclide release rate from waste form dissolution can be constrained by container failure time. The partial opening area of the container surface may decrease radionuclide release. Radionuclides sequestered by various chemical reactions in the near field of a failed container may become stable with time as the radiation level decreases with time.

  8. Transfer of accidentally released radionuclides in agricultural systems (TARRAS)

    International Nuclear Information System (INIS)

    Cancio, D.; Maubert, Colle; Rauret, G.; Grandison, A.S.

    1993-01-01

    The aim of this project is to contribute to the reliability of radiological assessment methods and establish a scientific base for the design of post-accident countermeasures. Three main aspects are considered in this project: A simulated accidental source term is used and the behaviour of aerosol deposits containing Sr, Cs and Ag isotopes are followed in some European soil-crop systems; the modification of radionuclide transfer rates through the food chain by well established food processing techniques is studied for Sr, Cs, Co and Ru; the project includes a study on the specific mediterranean diet and transfer data that are compared with currently used generic parameters. Seven contributions of the project for the reporting period are presented. (R.P.) 11 figs., 12 tabs

  9. Important processes affecting the release and migration of radionuclides from a deep geological repository

    International Nuclear Information System (INIS)

    Barátová, Dana; Nečas, Vladimír

    2017-01-01

    The processes that affect significantly the transport of contaminants through the near field and far field of a deep geological repository of spent nuclear fuel were studied. The processes can be generally divided into (i) processes related to the release of radionuclides from the spent nuclear fuel; (ii) processes related to the radionuclide transport mechanisms (such as advection and diffusion); and (iii) processes affecting the rate of radionuclide migration through the multi-barrier repository system. A near-field and geosphere model of an unspecified geological repository sited in a crystalline rock is also described. Focus of the treatment is on the effects of the different processes on the activity flow of the major safety-relevant radionuclides. The activity flow was simulated for one spent fuel cask by using the GoldSim simulation tool. (orig.)

  10. Workload Control with Continuous Release

    NARCIS (Netherlands)

    Phan, B. S. Nguyen; Land, M. J.; Gaalman, G. J. C.

    2009-01-01

    Workload Control (WLC) is a production planning and control concept which is suitable for the needs of make-to-order job shops. Release decisions based on the workload norms form the core of the concept. This paper develops continuous time WLC release variants and investigates their due date

  11. Mathematical modeling of radionuclide release through a borehole in a radioactive waste repository

    International Nuclear Information System (INIS)

    Choi, Heui Joo

    1996-02-01

    The effects of inadvertent human intrusion as a form of direct drilling into a radioactive waste repository are discussed in this thesis. It has been mentioned that the inadvertent direct drilling into the repository could provide a release pathway for radionuclides even with its low occurrence probability. The following analyses are carried out regarding the problem. The maximum concentration in a water-filled borehole penetrating a repository is computed with a simple geometry. The modeling is based upon the assumption of the diffusive mass transfer in the waste forms and the complete mixing in the borehole. It is shown that the maximum concentrations of six radionuclides in the borehole could exceed the Maximum Permissible Concentration. Also, the diffusive mass transport in a water-filled borehole is investigated with a solubility-limited boundary condition. An analytic solution is derived for this case. Results show that the diffusive mass transport is fast enough to justify the assumption of the complete mixing compared with the considered time span. The axial diffusive mass transport along a water-filled borehole is modeled to compute the release rate taking account of the rock matrix diffusion. The results show that the release of short-lived radionuclides are negligible due to the low concentration gradient in early time and the rock matrix diffusion. The release rates of four long-lived radionuclides are computed. It is also shown that the model developed could be applied to a borehole at a non-cylindrically shaped repository and the off-center drilling of a cylindrical repository. The release rates of long-lived nuclides through a porous material-filled borehole are computed. The results show that the release of all the long-lived nuclides is negligible up to half million years in the case that the borehole is filled with the porous material. The radiological effects of the nuclides released through the borehole penetrating the repository are computed

  12. Pathways to man for radionuclides released from disposal sites on land

    International Nuclear Information System (INIS)

    Hill, M.D.

    1986-01-01

    To predict the potential radiological impact on man of the disposal of radioactive wastes it is necessary to identify all the events and processes that could cause releases of radionuclides into the environment, to estimate their probabilities of occurrence and to calculate their consequences, for both individuals and populations. This paper briefly reviews the types of releases that have to be considered for land disposal sites and describes the mathematical models used to calculate rates of transport of radionuclides through the environment and doses to man. The difficulties involved in predicting environmental conditions in the far future are discussed, in the light of the ways in which the results of consequence calculations will be used. Assessments of land disposal of long-lived and highly radioactive wastes are briefly reviewed, with the aim of identifying the most important radionuclides and exposure pathways, and the areas where the models and their databases require improvement. (author)

  13. Uncertainty estimates for predictions of the impact of breeder-reactor radionuclide releases

    International Nuclear Information System (INIS)

    Miller, C.W.; Little, C.A.

    1982-01-01

    This paper summarizes estimates, compiled in a larger report, of the uncertainty associated with models and parameters used to assess the impact on man radionuclide releases to the environment by breeder reactor facilities. These estimates indicate that, for many sites, generic models and representative parameter values may reasonably be used to calculate doses from annual average radionuclide releases when these calculated doses are on the order of one-tenth or less of a relevant dose limit. For short-term, accidental releases, the uncertainty in the dose calculations may be much larger than an order of magnitude. As a result, it may be necessary to incorporate site-specific information into the dose calculation under such circumstances. However, even using site-specific information, inherent natural variability within human receptors, and the uncertainties in the dose conversion factor will likely result in an overall uncertainty of greater than an order of magnitude for predictions of dose following short-term releases

  14. Estimate of radionuclide release characteristics into containment under severe accident conditions

    International Nuclear Information System (INIS)

    Nourbakhsh, H.P.

    1993-11-01

    A detailed review of the available light water reactor source term information is presented as a technical basis for development of updated source terms into the containment under severe accident conditions. Simplified estimates of radionuclide release and transport characteristics are specified for each unique combination of the reactor coolant and containment system combinations. A quantitative uncertainty analysis in the release to the containment using NUREG-1150 methodology is also presented

  15. Review of radionuclides released from the nuclear fuel cycle and methods of assessing dose to man

    International Nuclear Information System (INIS)

    Bryant, P.M.

    1979-01-01

    There are two broad subject areas associated with releases of radionuclides from nuclear fuel cycle installations to the environment in which there are biological implications. One concerns interpretation of doses to man in terms of their radiological significance; the other concerns estimation of environmental transfer of radionuclides and of associated radiation doses to man. The radiation protection philosophy on which past practice regarding effluent releases of radionuclides to the environment was based is illustrated by drawing upon estimates of the associated radiation doses to man given in the 1977 report of the United Nations Scientific Committee on the Effects of Atomic Radiation. The present emphasis in radiation protection philosophy is illustrated by summarizing a review of environmental models relevant to estimation of radiation doses to population groups with reference to effluent releases of 3 H, 14 C, 85 Kr and 129 I; the author carried out the review as a contribution to a current study by an expert group set up by the Nuclear Energy Agency of OECD. Radionuclides of significance in the future may differ from those currently released to the environment because of possible developments in nuclear fuel cycles and options which may be exercised for disposal of high-level radioactive wastes, already in storage or postulated to be produced in the future. (author)

  16. Dispersion of radionuclides potentially released from the Atolls of Mururoa and Fangataufa to neighboring archipelagos

    International Nuclear Information System (INIS)

    Osvath, I.

    1999-01-01

    This paper presents a compartmental model developed to simulate dispersion of radionuclides released to the ocean from the atolls of Mururoa and Fangataufa on a scale of 3000 x 1700 km (150 deg. to 300 deg. S latitude, 130 deg. to 160 deg. W longitude), including the Tuamotu, Cook, Society, Gambier and Austral archipelagos

  17. Evaluation of Radionuclide Release from Aluminum-Based SNF in Basin Storage

    International Nuclear Information System (INIS)

    Sindelar, R.L.; Burke, S.D.; Howell, J.P.

    1998-09-01

    This report provides an evaluation of the release rates of radionuclides from breached A1-SNF assemblies and evaluates the effect of direct storage of breached fuel at a conservative upper bound reference condition on the SRS basin water activity levels

  18. Balance and behavior of gaseous radionuclides released during initial fast reactor fuel reprocessing operations

    International Nuclear Information System (INIS)

    Leudet, A.; Goumondy, J.P.; Charrier, G.

    1985-10-01

    Five pins from the fast reactor Phenix are cut and dissolved in a specially designed cell for the accurate determination of gas released during the operation. Amount and activity of gaseous radionuclides: Kr, Xe, Kr-85, I, I-129, H-3 and C-14 are determined in the fuel pins and also their distribution between shearing and dissolution [fr

  19. Proceedings of the workshop on radionuclide release scenarios for geologic repositories

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    The safety of radioactive waste disposal in geological formations cannot be verified experimentally. Safety analysis provides the only means to ensure that all risks associated with the waste repositories are acceptably low. The definition of radionuclide release scenarios, as discussed in these proceeedings, is the first step in the safety analysis of waste repositories.

  20. Design of environment monitoring system to evaluate radionuclide release from subsystem on PWR nuclear power accident

    International Nuclear Information System (INIS)

    Sri Kuntjoro; Sugiyanto; Pande Made Udiyani; Jupiter Sitorus Pane

    2012-01-01

    Nuclear Power Plan (NPP) as a renewable energy source is selected as an alternative, because it has many advantages that is environmentally friendly, fuel supply which is independent of the season, and the price that can compete with other power plants. However, the existence of some public skepticism about nuclear radiation safety, the government must be convinced about the operation of nuclear power plants are safe and secure. Research on the design of environment monitoring system for evaluation of radionuclide release from the reactor subsystems and the environment due to accidents at power reactors has been done. The study was conducted by calculating the distribution of radionuclide release into the reactor subsystem and the environment and also to build the environment radiation monitoring system. Environmental monitoring system consists of a radiation counter, early warning systems, meteorological measurement systems, GPS systems and GIS. Radiation monitoring system used to record the data of radiation, meteorological measurement system used to record data of wind and speed direction, while the GPS system is used to determine position of data measurements. The data is then transmitted to a data acquisition system and then to be transmitted to the control center. Collection and transmission of data is done via SMS formatting using a modem device that is placed in the control center. The control center receives measurement data from various places. In this case the control center has a function as an SMS Gateway. This system can visualize for different measurement locations. Furthermore, radiation data and position data to be integrated with digital maps. System integration is then visualized in a personal computer. To position of measurements directly visualized on the map and also look for the data displayed on a monitor as a red or green circle colour. That colour indicated as a safe limit of radiation monitor. When the cycle colour is red, the system will

  1. Effect of buffer thickness on the retardation of radionuclide release from the high-level waste repository

    International Nuclear Information System (INIS)

    Cho, Won Jin; Lee, Jae Owan; Kang, Chul Hyung; Han, Kyung Won

    2000-12-01

    The radionuclide release from buffer in the high-level waste repository to the surrounding host rock was assessed, and the effect of the radial buffer thickness on the release rate was analyzed. The total release rates decrease sharply with increasing radial buffer thickness up to 0.25 m, and decrease moderately at the buffer thickness between 0.25 m and 0.5 m. But increasing the radial buffer thickness beyond 0.5 m has little effect in reducing radionuclide release. Therefore a radial buffer thickness between 0.25 m and 0.5 m is sufficient based on the viewpoint of radionuclide retention

  2. HADOC: a computer code for calculation of external and inhalation doses from acute radionuclide releases

    International Nuclear Information System (INIS)

    Strenge, D.L.; Peloquin, R.A.

    1981-04-01

    The computer code HADOC (Hanford Acute Dose Calculations) is described and instructions for its use are presented. The code calculates external dose from air submersion and inhalation doses following acute radionuclide releases. Atmospheric dispersion is calculated using the Hanford model with options to determine maximum conditions. Building wake effects and terrain variation may also be considered. Doses are calculated using dose conversion factor supplied in a data library. Doses are reported for one and fifty year dose commitment periods for the maximum individual and the regional population (within 50 miles). The fractional contribution to dose by radionuclide and exposure mode are also printed if requested

  3. Birth control - slow release methods

    Science.gov (United States)

    Contraception - slow-release hormonal methods; Progestin implants; Progestin injections; Skin patch; Vaginal ring ... might want to consider a different birth control method. SKIN PATCH The skin patch is placed on ...

  4. Individual doses from radionuclides released to the Baltic coast

    International Nuclear Information System (INIS)

    Bergstroem, U.; Nordlinder, S.

    1991-01-01

    Individual doses to critical groups from a continuous unit release of nuclides from high-level waste to a coast area were calculated. The selection of nuclides for this study was based on experience of their importance from a radiological point of view. The coastal area should be representative for average conditions along the Swedish Baltic coast. The costal area was simulated in the model by compartments for water and sediment, respectively. Six exposure pathways for activity from the water and sediment reservoirs were considered. The ecosystem was assumed to be similar to present conditions in Sweden. This was also the case concerning diet and living habits. In addition, the doses from naturally occurring nuclides in the uranium decay chains were calculated, based on natural levels. The calculations were carried out with the BIOPATH and PRISM codes. The latter code was used to obtain the uncertainty in the results due to the uncertainty in the input parameter values. (au) (34 refs., 15 tbls.)

  5. Modelling the dispersion of radionuclides following short duration releases to rivers

    International Nuclear Information System (INIS)

    Smith, J.T.; Bowes, M.; Denison, F.H.

    2003-01-01

    This project develops a model for assessing short duration liquid discharges of radionuclides to rivers. The assessment of doses arising from discharges to rivers is normally carried out by considering annual average discharge rates. Actual authorised discharges, however, may occur unevenly during the year or relatively high short-term discharges could occur in the unlikely event of an incident. Short term radionuclide releases could potentially result in temporary increases in radionuclide activity concentrations in water and fish which are greater than those resulting from a continuous discharge. The purpose of this project is to develop a model to assess short term releases from these sites, and where possible develop generic methods of assessing short term releases. An advection-dispersion model was developed to predict the concentrations of radionuclides in the river environment, ie in river water, river bed sediment and in predatory fish. Uptake of radionuclides to fish was modelled by estimating rates of uptake of radionuclides via the aquatic food chain or across the gill, as appropriate. The model was used to predict the concentrations of the radionuclides in the river Thames and its tributaries as a result of short duration discharges into stretches of the Thames and River Colne. Model output is given as a series of graphs of activity concentration and time integrated activity concentration resulting from a 1 MBq discharge for the following release durations: 5 minutes, 1 h, 3 h, 12 h and 24 h. The five locations for which predictions are given were 100m, 300m, 1000m, 3000m and 10000m downstream. The river volumetric flow rate was shown to be the most important environmental variable determining activity concentrations in water, fish and sediments following a release. In general, the maximum and integrated activity concentrations in water and fish will be in inverse proportion to the river volumetric flow rate, for a given amount and duration of release

  6. [Ranking of radionuclides and pathways according to their contribution to the dose burden to the population resulting from NPP releases].

    Science.gov (United States)

    Spiridonov, S I; Karpenko, E I; Sharpan, L A

    2013-01-01

    Approaches are described towards estimating the consequences of radioactive contamination of ecosystems by nuclear fuel cycle enterprises with the rationale for the optimal specification level for nuclear power plants (NPP) operating in the normal mode. Calculations are made based on the initial data of the IAEA project, INPRO ENV, dealing with the ranking of radionuclides escaping to the environment from the operating NPPs. Influence of various factors on rankings of radionuclides and pathways of public exposure is demon- strated. An important factor is the controlled radionuclide composition of atmospheric NPP releases. It has been found that variation in the dose coefficients for some radionuclides leads to significant changes not only in the ranking results but also in the estimates of total dose burdens. Invariability is shown of the estimation concerning the greatest contribution of the peroral route to the population dose of irradiation in the situation considered. A conclusion was drawn on the need of taking into consideration uncertainties of different factors when comparing effects on the environment from enterprises of conventional and innovative nuclear fuel cycles.

  7. Development of computer model for radionuclide released from shallow-land disposal facility

    International Nuclear Information System (INIS)

    Suganda, D.; Sucipta; Sastrowardoyo, P.B.; Eriendi

    1998-01-01

    Development of 1-dimensional computer model for radionuclide release from shallow land disposal facility (SLDF) has been done. This computer model is used for the SLDF facility at PPTA Serpong. The SLDF facility is above 1.8 metres from groundwater and 150 metres from Cisalak river. Numerical method by implicit method of finite difference solution is chosen to predict the migration of radionuclide with any concentration.The migration starts vertically from the bottom of SLDF until the groundwater layer, then horizontally in the groundwater until the critical population group. Radionuclide Cs-137 is chosen as a sample to know its migration. The result of the assessment shows that the SLDF facility at PPTA Serpong has the high safety criteria. (author)

  8. Integrated performance assessment model for waste policy package behavior and radionuclide release

    International Nuclear Information System (INIS)

    Kossik, R.; Miller, I.; Cunnane, M.

    1992-01-01

    Golder Associates Inc. (GAI) has developed a probabilistic total system performance assessment and strategy evaluation model (RIP) which can be applied in an iterative manner to evaluate repository site suitability and guide site characterization. This paper describes one component of the RIP software, the waste package behavior and radionuclide release model. The waste package component model considers waste package failure by various modes, matrix alteration/dissolution, and radionuclide mass transfer. Model parameters can be described as functions of local environmental conditions. The waste package component model is coupled to component models for far-field radionuclide transport and disruptive events. The model has recently been applied to the proposed repository at Yucca Mountain

  9. Integrated performance assessment model for waste package behavior and radionuclide release

    International Nuclear Information System (INIS)

    Kossik, R.; Miller, I.; Cunnane, M.

    1992-01-01

    Golder Associates Inc. (GAI) has developed a probabilistic total system performance assessment and strategy evaluation model (RIP) which can be applied in an iterative manner to evaluate repository site suitability and guide site characterization. This paper describes one component of the RIP software, the waste package behavior and radionuclide release model. The waste package component model considers waste package failure by various modes, matrix alteration/dissolution, and radionuclide mass transfer. Model parameters can be described as functions of local environmental conditions. The waste package component model is coupled to component models for far-field radionuclide transport and disruptive events. The model has recently been applied to the proposed repository at Yucca Mountain

  10. Assessment of atmospherically-released radionuclides using the computerized radiological risk investigation system

    International Nuclear Information System (INIS)

    Nelson, C.B.; Sjoreen, A.L.; Miller, C.W.; Baes, C.F. III.

    1986-01-01

    For radionuclides, the standards are in terms of an annual dose, and the regulations require assurance that no member of the general public receives a dose in excess of that standard. Thus, spatial variations in the population around an emission source must be considered. Furthermore, for most chemical pollutants the standards are written in terms of an air concentration while for radionuclides other pathways of exposure, e.g., uptake of the airborne emissions by terrestrial food chains must also be considered. The remainder of this paper discusses the computer codes that make up the CRRIS and how they are used to perform an assessment of the health impacts on man of radionuclides released to the atmosphere

  11. Comparison of US/FRG accident condition models for HTGR fuel failure and radionuclide release

    International Nuclear Information System (INIS)

    Verfondern, K.

    1991-03-01

    The objective was to compare calculation models used in safety analyses in the US and FRG which describe fission product release behavior from TRISO coated fuel particles under core heatup accident conditions. The frist step performed is the qualitative comparison of both sides' fuel failure and release models in order to identify differences and similarities in modeling assumptions and inputs. Assumptions of possible particle failure mechanisms under accident conditions (SiC degradation, pressure vessel) are principally the same on both sides though they are used in different modeling approaches. The characterization of a standard (= intact) coated particle to be of non-releasing (GA) or possibly releasing (KFA/ISF) type is one of the major qualitative differences. Similar models are used regarding radionuclide release from exposed particle kernels. In a second step, a quantitative comparison of the calculation models was made by assessing a benchmark problem predicting particle failure and radionuclide release under MHTGR conduction cooldown accident conditions. Calculations with each side's reference method have come to almost the same failure fractions after 250 hours for the core region with maximum core heatup temperature despite the different modeling approaches of SORS and PANAMA-I. The comparison of the results of particle failure obtained with the Integrated Failure and Release Model for Standard Particles and its revision provides a 'verification' of these models in this sense that the codes (SORS and PANAMA-II, and -III, respectively) which were independently developed lead to very good agreement in the predictions. (orig./HP) [de

  12. Release criteria for patients having undergone radionuclide therapy and criteria for their crossing the state border of the Russian Federation

    International Nuclear Information System (INIS)

    Zvonova, I.; Balonov, M.; Golikov, V.

    2011-01-01

    By means of a conservative dosimetry model, the values of operational radiological criteria for patients released from hospital-residual activity in a body and dose rate near the patient's body-are substantiated based on the effective dose limit of 5 mSv for persons helping the patient or living with him and 1 mSv for other adults and children. Two sets of operative criteria for radionuclides 125 I, 131 I, 153 Sm and 188 Re used in Russia for radionuclide therapy were derived. Release criteria for 125 I well differ from such values in other countries because in this work absorption of 125 I low-energy photon radiation in the patient was taken into account. When a patient having undergone radionuclide therapy crosses the frontier of Russia, high-sensitivity devices for radiation control at the custom can detect the patient. A simplified radiological assessment of the patient was suggested aimed at provision of radiation safety for patient companions in transport. (authors)

  13. Release of patients after radionuclide therapy. With contributions from the [International Commission on Radiological Protection] ICRP

    International Nuclear Information System (INIS)

    2009-01-01

    The use of unsealed radiopharmaceuticals for treatment of disease is common practice worldwide. This approach was widely employed some years ago and, following a decline, there has recently been a resurgence of interest in it. The combination of newly accessible radionuclides, improved labelling technology and developments in biotechnology has resulted in more enthusiasm and a wider range of applications for this form of therapy. Radionuclide treatments are performed with either the patient admitted to hospital or as an outpatient only. The criteria to determine which approach is best vary considerably, and are not always closely linked with the well established standards of radiation protection practice. Safety issues for the patient, their family, associated carers, staff and the general public arise with either approach. The potential risks are from both external irradiation and contamination. The International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (BSS) specify the dose constraints and limits for all of these groups, and their more general provisions with respect to the as low as reasonably achievable principle and justification also apply. One way of managing exposures of the various groups is to control when patients are released from hospital. While they are in hospital, it is relatively easy to control exposure. Once they have returned to their family in the community, they must be advised on how to restrict the exposure of those people that they will come into contact with. Until recently, the International Commission on Radiological Protection (ICRP) did not provide specific advice in this area, and relied on the application of dose limits and constraints. However, regulators in some countries took a prescriptive approach, often using estimates of retained activity as a release criterion. These only loosely relate to dose limits. This publication attempts to bring newly available advice

  14. Controlled Release from Recombinant Polymers

    Science.gov (United States)

    Price, Robert; Poursaid, Azadeh; Ghandehari, Hamidreza

    2014-01-01

    Recombinant polymers provide a high degree of molecular definition for correlating structure with function in controlled release. The wide array of amino acids available as building blocks for these materials lend many advantages including biorecognition, biodegradability, potential biocompatibility, and control over mechanical properties among other attributes. Genetic engineering and DNA manipulation techniques enable the optimization of structure for precise control over spatial and temporal release. Unlike the majority of chemical synthetic strategies used, recombinant DNA technology has allowed for the production of monodisperse polymers with specifically defined sequences. Several classes of recombinant polymers have been used for controlled drug delivery. These include, but are not limited to, elastin-like, silk-like, and silk-elastinlike proteins, as well as emerging cationic polymers for gene delivery. In this article, progress and prospects of recombinant polymers used in controlled release will be reviewed. PMID:24956486

  15. Modelling for radiological and radioecological consequences of an accidental radionuclide release at Sea

    International Nuclear Information System (INIS)

    Paschoa, A.S.

    1997-01-01

    Full text: Scenarios concerning accidental releases of radionuclides into water bodies can be found in the open literature, mostly in connection with nuclear power plants located either onshore or inland. However, meager attention has been given to nuclear reactors used as energy sources for propulsion at sea, which are also subject to accidents. Such potential accidents may involve the loss of part of the reactor core to the surrounding water body. In addition of the initial instantaneous releases, one can estimate delayed source terms based on the rate at which radionuclides are dissolved or leached from the solidified material, like part of the core or structural materials in contact with water. Most of such solidified material might be a mixture of uranium, zirconium, iron, calcium, silica, fission and activation products, and transuranium elements as oxides, forming a glassy type solid. Transport models were used to calculate radionuclide concentrations in water resulting from short and delayed source terms. Oceanographic data used in the calculations were taken either from the open literature or from unclassified reports of the Brazilian Navy, being, however, as generic as possible. Time-dependent concentration functions for radionuclides in aquatic food following an accidental release reflect the net result of intake and elimination processes. However, to avoid the complexities of multiple parameters involved in such processes, the model accounts only for trophic transfer of radionuclides, and yet avoids the necessity of analyzing the details of each transfer step used to determine fish, crustacea, molluscs and seaweed accumulation. Swimming and other aquatic sports are not included in the model used for dose calculations because of theirs relatively low importance in comparison with the pathways concerning ingestion of aquatic food

  16. Mechanisms controlling radionuclide mobility in forest soils

    International Nuclear Information System (INIS)

    Delvaux, B.; Kruyts, N.; Maes, E.; Agapkina, G.I.; Kliashtorin, A.; Bunzl, K.; Rafferty, B.

    1996-01-01

    Soil processes strongly influence the radionuclide mobility in soils. The mobility of radionuclides in forest soils is governed by several processes involving both abiotic and biotic factors. The sorption-desorption process chiefly governs the activity of radionuclides in the soil solution, hence thereby their mobility and biological availability. Radiocaesium exhibits a very low mobility in mineral soils. Both mobility and bioavailability however increase as the thickness of organic layers and their content in organic matter increases. Clay minerals of micaceous origin strongly act as slinks for radiocaesium in forest soils. The magnitude of cesium mineral fixation in topsoils is expected to be the highest in mineral soils of Eutric cambisol type, and, to a lesser extent, of type of Distric cambisol and Podzoluvisol. A low mobility of radiocaesium in the surface horizons of forest soils may also be partially explained by a biological mobilization: fungi absorb radiocaesium and transport it to upper layers, thereby contributing to constantly recycle the radioelement in the organic horizons. This mechanism is probably important in soils with thick organic layers (Podsol, Histosol, and, to a lesser extent, Distric cambisol and Podzoluvisol). Radionuclides can be associated with soluble organic anions in the soil solution of forest acid soils. Such associations are highly mobile: they are stable in conditions of poor biological activity (low temperatures, acid soil infertility, water excess, etc.). Their magnitude is expected to be the highest in thick acid organic layers (soils of type Podzol and Histosol)

  17. SUBDOSA: a computer program for calculating external doses from accidental atmospheric releases of radionuclides

    International Nuclear Information System (INIS)

    Strenge, D.L.; Watson, E.C.; Houston, J.R.

    1975-06-01

    A computer program, SUBDOSA, was developed for calculating external γ and β doses to individuals from the accidental release of radionuclides to the atmosphere. Characteristics of SUBDOSA are: doses from both γ and β radiation are calculated as a function of depth in tissue, summed and reported as skin, eye, gonadal, and total body dose; doses are calculated for releases within each of several release time intervals and nuclide inventories and atmospheric dispersion conditions are considered for each time interval; radioactive decay is considered during the release and/or transit using a chain decay scheme with branching to account for transitions to and from isomeric states; the dose from gamma radiation is calculated using a numerical integration technique to account for the finite size of the plume; and the program computes and lists the normalized air concentrations at ground level as a function of distance from the point of release. (auth)

  18. Model to estimate the local radiation doses to man from the atmospheric release of radionuclides (LWBR development program)

    International Nuclear Information System (INIS)

    Rider, J.L.; Beal, S.K.

    1977-04-01

    A model was developed to estimate the radiation dose commitments received by people in the vicinity of a facility that releases radionuclides into the atmosphere. This model considers dose commitments resulting from immersion in the plume, ingestion of contaminated food, inhalation of gaseous and suspended radioactivity, and exposure to ground deposits. The dose commitments from each of these pathways is explicitly considered for each radionuclide released into the atmosphere and for each daughter of each released nuclide. Using the release rate of only the parent radionuclide, the air and ground concentrations of each daughter are calculated for each position of interest. This is considered to be a significant improvement over other models in which the concentrations of daughter radionuclides must be approximated by separate releases

  19. Effects of indoor residence on radiation doses from routine releases of radionuclides to the atmosphere

    International Nuclear Information System (INIS)

    Kocher, D.C.

    1980-01-01

    Dose reduction factors from indoor residence during routine releases of radionuclides to the atmosphere were studied using models that are suitable for application to arbitrary source terms. Dose reduction factors for internal exposure to inhaled radionuclides account for air ventilation and deposition on inside building surfaces. Estimated internal dose reduction factors are approx. 0.2 to 0.8 for particulates and 0.07 to 0.4 for radioiodine. Dose reduction factors for external photon exposure from airborne and surface-deposited sources are based on the point-kernel integration method. Values for source terms from a fuel reprocessing plant and a hypothetical reactor accident are within a factor of 2 of the value 0.5 adopted by the US Nuclear Regulatory Commission (NRC) for population dose assessments. For the release at Three Mile Island nuclear station, however, the external dose reduction factor may be an order of magnitude less than the value adopted by the NRC

  20. Simplified analytical model to simulate radionuclide release from radioactive waste trenches

    International Nuclear Information System (INIS)

    Sa, Bernardete Lemes Vieira de

    2001-01-01

    In order to evaluate postclosure off-site doses from low-level radioactive waste disposal facilities, a computer code was developed to simulate the radionuclide released from waste form, transport through vadose zone and transport in the saturated zone. This paper describes the methodology used to model these process. The radionuclide released from the waste is calculated using a model based on first order kinetics and the transport through porous media was determined using semi-analytical solution of the mass transport equation, considering the limiting case of unidirectional convective transport with three-dimensional dispersion in an isotropic medium. The results obtained in this work were compared with other codes, showing good agreement. (author)

  1. Radionuclide release and aerosol generation during core debris interactions with concrete

    International Nuclear Information System (INIS)

    Powers, D.A.

    1986-01-01

    During severe accidents at nuclear power plants, it is possible for the reactor fuel to melt and penetrate the reactor vessel. This can lead to vigorous interaction of core materials (UO 2 , ZrO 2 , Zr, and stainless steel) with structural concrete. Sparging of the molten core debris by gases (H 2 O and CO 2 ) liberated from the concrete can lead to rapid release of radionuclides from the core debris. A theoretical description of this release process has been developed and is called the VANESA model. The treatments in the VANESA model of the thermodynamics of radionuclide vaporization and the kinetic barriers to vaporization will be described. Predictions obtained from the model will be compared to the results of tests of core debris/concrete interactions

  2. Conditions inside Water Pooled in a Failed Nuclear Waste Container and its Effect on Radionuclide Release

    Science.gov (United States)

    Hamdan, L. K.; Walton, J. C.; Woocay, A.

    2009-12-01

    Nuclear power use is expected to expand in the future, as part of the global clean energy initiative, to meet the world’s surging energy demand, and attenuate greenhouse gas emissions, which are mainly caused by fossil fuels. As a result, it is estimated that hundreds of thousands of metric tons of spent nuclear fuel (SNF) will accumulate. SNF disposal has major environmental (radiation exposure) and security (nuclear proliferation) concerns. Storage in unsaturated zone geological repositories is a reasonable solution for dealing with SNF. One of the key factors that determine the performance of the geological repository is the release of radionuclides from the engineered barrier system. Over time, the nuclear waste containers are expected to fail gradually due to general and localized corrosions and eventually infiltrating water will have access to the nuclear waste. Once radionuclides are released, they will be transported by water, and make their way to the accessible environment. Physical and chemical disturbances in the environment over the container will lead to different corrosion rates, causing different times and locations of penetration. One possible scenario for waste packages failure is the bathtub model, where penetrations occur on the top of the waste package and water pools inside it. In this paper the bathtub-type failed waste container is considered. We shed some light on chemical and physical processes that take place in the pooled water inside a partially failed waste container (bathtub category), and the effects of these processes on radionuclide release. Our study considers two possibilities: temperature stratification of the pooled water versus mixing process. Our calculations show that temperature stratification of the pooled water is expected when the waste package is half (or less) filled with water. On the other hand, when the waste package is fully filled (or above half) there will be mixing in the upper part of water. The effect of

  3. Impact assessment of radionuclides released to environment from the European Spallation Source

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, S.; Andersson, K. [Technical University of Denmark (Denmark); Ene, D. [European Spallation Soure AB - ESS, Lund (Sweden)

    2014-07-01

    The European Spallation Source (ESS) is a large science and technology infrastructure project currently under construction in Lund, Sweden, with operation planned by 2019. The facility design and construction includes a linear proton accelerator, a heavy-metal target station, neutron instruments, laboratories, and a data management and software development centre. During operation the ESS will produce a wide range of radionuclides via spallation and activation processes. Radiological assessments are needed to ensure that operational discharges and releases from potential incidents/accidents are within acceptable limits. The spectrum of radionuclides produced at ESS is quite different from that produced in nuclear power plants and assessment work has therefore been challenged by lack of information on less well-known radionuclides. Traditional assessment methodologies have been applied focusing on releases to air and public sewer systems and calculating radiation doses to representative persons living in and near Lund close to the ESS site. Exposure pathways considered include external radiation from radionuclides in air, external radiation from radionuclides deposited on ground and skin, inhalation of radionuclides and ingestion of locally produced contaminated food. Atmospheric dispersion has been simulated with the Gaussian plume model which is considered adequate within a few kilometres. Effects of release height have been investigated and site specific values of other parameters such as wind speed, wind direction, rain fall etc. have been used. Contamination of food has been calculated from the (ECOSYS) food dose model used in the RODOS and ARGOS decision support systems. The food dose model does not contain specific data for a number of ESS relevant radionuclides, e.g. {sup 7}Be, {sup 32}P and {sup 35}S. The data required include mobility of these isotopes, soil-to-plant concentration ratios and equilibrium transfer factors of daily intake by ingestion of meat

  4. Radiological consequences of radionuclide releases to sewage systems from hospitals in Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Avila, Rodolfo; Cruz, Idalmis de la [Facilia AB (Sweden); Bergman, Synnoeve [Vattenfall Power Consultants AB (Sweden); Hasselblad, Serena [Callido AB (Sweden)

    2007-08-15

    The report addresses radioactive discharges to sewers originating from hospitals, mainly in the form of the excretion of patients treated with radioisotopes for diagnostic or therapeutic purposes. Assessments of doses to the public, including sewage workers, arising from such discharges are performed. Doses are compared against the exemption level of 10 {mu}Sv/a and the dose constraint of 100 {mu}Sv/a. As a basis for the dose assessments, information on the use of radionuclides in Swedish hospitals during the period 1999-2004 is presented and estimates of discharges to the sewage systems are derived. Current sewage treatment practices in Sweden are summarised focusing particularly on the fate of sewage sludge, both in the sewage plant and outside. Radiological impact assessments are performed in two steps. The assessments in the first stage are performed using a simple screening model, not intending to predict exposures realistically but only to identify exposure pathways and radionuclides that are potentially relevant and require further consideration in the more detailed assessments. Results show that only a few of those radionuclides used in the period 1999-2004 in Swedish hospitals for radiotherapy and radiodiagnostics could lead to potentially significant doses (P-32, Y-90, Tc-99m, In-111, I-123, I-131 and Tl-201). Relevant exposure pathways are the external exposure of sewage workers (for Tc- 99m, I-123, I-131, In-111 and Tl-201) and the exposure of the public via ingestion of water (I-131) and fish (P-32, Y-90 and In-111 and I-131). The objective of the second stage is to perform realistic assessments of the doses to sewage workers and to the public through the use of contaminated agricultural sludge and through the contamination of drinking water. For this purpose, the LUCIA model was developed. This model dynamically addresses the behaviour of radionuclides in the different process steps of a sewage plant. The model can address continuous releases as well

  5. A quality control exercise of radionuclide calibrators among Belgian hospitals

    International Nuclear Information System (INIS)

    Reher, D.F.G.; Merlo, P.

    1990-01-01

    On the initiative of the Belgian Association of Hospital Physicists, eleven Belgian hospitals participated in a quality control of radionuclide calibrators conducted in collaboration with the Central Bureau for Nuclear Measurements of the Commission of the European Communities. For practical reasons the nuclide 57 Co was chosen. The results from 20 different radionuclide calibrators show a fair agreement with a similar comparison carried out in 1980 in the UK. (orig.)

  6. HABIT, Toxic and Radioactive Release Hazards in Reactor Control Room

    International Nuclear Information System (INIS)

    Stage, S.A.

    2005-01-01

    1 - Description of program or function: HABIT is a package of computer codes designed to be used for the evaluation of control room habitability in the event of an accidental release of toxic chemicals or radioactive materials. 2 - Methods: Given information about the design of a nuclear power plant, a scenario for the release of toxic or radionuclides, and information about the air flows and protection systems of the control room, HABIT can be used to estimate the chemical exposure or radiological dose to control room personnel

  7. Radionuclide behavior in water saturated porous media: Diffusion and infiltration coupling of thermodynamically and kinetically controlled radionuclide water - mineral interactions

    International Nuclear Information System (INIS)

    Spasennykh, M.Yu.; Apps, J.A.

    1995-05-01

    A model is developed describing one dimensional radionuclide transport in porous media coupled with locally reversible radionuclide water-mineral exchange reactions and radioactive decay. Problems are considered in which radionuclide transport by diffusion and infiltration processes occur in cases where radionuclide water-solid interaction are kinetically and thermodynamically controlled. The limits of Sr-90 and Cs-137 migration are calculated over a wide range of the problem variables (infiltration velocity, distribution coefficients, and rate constants of water-mineral radionuclide exchange reactions)

  8. Radionuclide release from PWR fuels in a reference tuff repository groundwater

    International Nuclear Information System (INIS)

    Wilson, C.N.; Oversby, V.M.

    1985-03-01

    The Nevada Nuclear Waste Storage Investigations Project (NNWSI) is studying the suitability of the welded devitrified Topopah Spring tuff at Yucca Mountain, Nye County, Nevada, for potential use as a high-level nuclear waste repository. In support of the Waste Package task of NNWSI, tests have been conducted under ambient air environment to measure radionuclide release from two pressurized water reactor (PWR) spent fuels in water obtained from the J-13 well near the Yucca Mountain site. Four specimen types, representing a range of fuel physical conditions that may exist in a failed waste canister containing a limited amount of water were tested. The specimen types were: fuel rod sections split open to expose bare fuel particles; rod sections with water-tight end fittings with a 2.5-cm long by 150-μm wide slit through the cladding; rod sections with water-tight end fittings and two 200-μm-diameter holes through the cladding; and undefected rod segments with water-tight end fittings. Radionuclide release results from the first 223-day test runs on H.B. Robinson spent fuel specimens in J-13 water are reported and compared to results from a previous test series in which similar Turkey Point reactor spent fuel specimens were tested on deionized water. Selected initial results are also given for Turkey Point fuel specimens tested on J-13 water. Results suggest that the actinides Pu, Am, Cm and Np are released congruently with U as the UO 2 spent fuel matrix dissolves. Fractional release of 137 Cs and 99 Tc was greater than that measured for the actinides. Generally, lower radionuclide releases were measured for the H.B. Robinson fuel in J-13 water than for Turkey Point Fuel in deionized water. 8 references, 7 figures, 9 tables

  9. A dynamic compartment model for evaluating transfer of radionuclide into rice-plant after acute release

    International Nuclear Information System (INIS)

    Keum, D.K.; Lee, H.S.; Choi, H.J.; Kang, H.S.; Lee, C.W.

    2004-01-01

    In this paper a dynamic compartment model is presented to estimate the transfer of radionuclides deposited on rice-fields after an accidental release. The present model includes a surface water compartment and a direct shoot-base absorption from the surface water to the rice plant to account for the flooded condition of rice-fields, which are major features discriminating the present model from the existing model. In order to test the validity of model, a number of simulated Cs-137 deposition experiments were performed while growing rice-plant in a green house. For the experiments the radionuclide was indirectly treated in the root zone soil before transplanting and on the surface water without a direct contamination of rice-plant after transplanting. In the first year of deposition the shoot-base absorption was a predominant process for the transfer of radionuclide into rice when the radionuclide was treated on the surface water, and from the second year, the root-uptake was dominant. The model calculation predicted reasonably well the first year experimental result showing the importance of shoot base absorption as well as the concentration of rice-body and grain measured from respective rice-plant grown consecutively on the contaminated soils for years. (author)

  10. Aspects of radiation exposure amongst the population after release of radionuclides from terminal stores

    International Nuclear Information System (INIS)

    Proehl, G.; Mueller, H.; Paretzke, H.G.

    1989-08-01

    The release of radionuclides from terminal stores may lead to the contamination of ground water lying close to the surface, after the radionuclides have migrated within the covering rock. Use of this water can result in radiation exposure for human beings along many exposure pathways. In order to assess the radiation exposure from these exposure pathways the model ECOSYS-87-B was developed, as an extension of ECOSYS (Jacobi et al. 1985). On the basis of a standardized contamination of the ground water, the potential radiation exposure of a one-year-old and an adult are calculated, under the assumption that the entire food supply of these persons was produced using radioactively contaminated water. Special questions on the transfer of radionuclides in food chains are discussed, and, in particular, the mineral content of the water and the influence of the chemical form of the radionuclides dissolved in the ground water on their transfer within the food chain are explained. There is also a study of the extent to which various physiologically-based nutritional habits influence the radiation exposure of a human being. Various criteria for the evaluation of radiation exposure are discussed. (orig./HP) [de

  11. Internal exposure of populations to long-lived radionuclides released into the environment

    International Nuclear Information System (INIS)

    Balonov, M.I.

    1997-01-01

    This chapter discusses the events that led to the contamination of environments with the long-lived radionuclides of caesium, strontium and other elements, and to the internal exposure of populations living in contaminated areas. Among these events are radioactive releases into the river Techa from the Soviet nuclear weapons facility Mayak in 1949-1956, thermonuclear weapons test in the 1950s and 1960s, the Kyshtim and Windscale accidents in 1957, and the Chernobyl and Tomsk-7 accidents in 1986 and 1993, respectively. Methods of environmental monitoring and individual internal dose monitoring of inhabitants are described. These are based on measuring the content of radionuclides not only in the air, drinking water and local food products, but also in humans using whole-body counters and analysing excreta and autopsy samples. The dynamics of internal exposure of people of different ages to radionuclides of caesium, strontium and plutonium from the environment are considered. Examples of radionuclide distributions in the environment, and of individual/collective internal doses and related medical effects are presented. (Author)

  12. Effluent release limits, sources and control

    International Nuclear Information System (INIS)

    Swindell, G.E.

    1977-01-01

    Objectives of radiation protection in relation to releases. Environmental transfer models for radionuclides. Relationship between releases, environmental levels and doses to persons. Establishment of release limits: Limits based on critical population group concept critical pathway analysis and identification of critical group. Limits based on optimization of radiation protection individual dose limits, collective doses and dose commitments 1) differential cost benefit analysis 2) authorized and operational limits taking account of future exposures. Monitoring of releases to the environment: Objectives of effluent monitoring. Typical sources and composition of effluents; design and operation of monitoring programmes; recording and reporting of monitoring results; complementary environmental monitoring. (orig.) [de

  13. Principles for the limitation of releases of radionuclides from nuclear power plants to the atmosphere. A model of food chain system

    International Nuclear Information System (INIS)

    Pensko, J.; Stpiczynska, Z.

    1976-01-01

    On the basis of reference data the principles are set up for the limitation of releases of radioactive substances from nuclear power plants to the environment to maintain the radiation exposure of population to the level of accepted dose limits. The main attention is paid to the transfer of radionuclides released through food chain to man. For that purpose the mathematical model of population exposure by food chain which relates the radiation doses to the activity of radionuclides released is presented. The Laplace transformation is used to simplify the solution of the differential equations. It is shown that the estimation of the population exposure with the aid of a food chain mathematical model not only gives the permissible limits of release but also indicates the ways of proper radiological control program in the environment of nuclear installations. (author)

  14. Chemical controls on subsurface radionuclide transport

    International Nuclear Information System (INIS)

    King, K.J.; Killey, R.W.D.

    1990-01-01

    Chemical and biochemical processes can affect the movement of contaminants in groundwater. Materials can be almost completely removed from circulation by processes such as precipitation and coprecipitation. Organic compounds or contaminants that are hazardous may be degraded or formed during groundwater transport. Studies at the Chalk River Laboratories of AECL have focused on radionuclide transport, although other contaminants have been and are being investigated. This paper summarizes findings from research that extends back more than 30 years. Much of the work on reactive contaminant transport has centered on 90 Sr; other contaminants have also been considered, however, and features of their behaviour are also reviewed. (25 refs., 5 figs., 4 tabs.)

  15. Dose evaluation model for radionuclides released from the spent nuclear fuel reprocessing plant in Rokkasho

    International Nuclear Information System (INIS)

    Hisamatsu, Shun'ichi; Iyogi, Takashi; Inaba, Jiro; Chiang, Jing-Hsien; Suwa, Hiroji; Koide, Mitsuo

    2007-01-01

    A dose evaluation model was developed for radionuclides released from the spent nuclear fuel reprocessing plant which is located in Rokkasho, Aomori Prefecture, and now undergoing test operation. The dose evaluation model suitable for medium- and long-term dose assessments for both prolonged and short-term releases of radionuclides to the atmosphere was developed on the PC. The ARAC-2, a particle tracing type dispersion model coupled with 3-D wind field calculation by a mass conservative model, was adopted as the atmospheric dispersion model. The terrestrial transfer model included movement in soil and groundwater as well as an agricultural and livestock farming system. The available site-specific social and environmental characteristics were incorporated in the model. Growing of the crops was also introduced and radionuclides absorbed were calculated from weight increase from the start of deposition to harvest, and transfer factors. Most of the computer code system of the models was completed by 2005, and this paper reports the results of the development. (author)

  16. Release of radionuclides following severe accident in interim storage facility. Source term determination

    International Nuclear Information System (INIS)

    Morandi, S.; Mariani, M.; Giacobbo, F.; Covini, R.

    2006-01-01

    Among the severe accidents that can cause the release of radionuclides from an interim storage facility, with a consequent relevant radiological impact on the population, there is the impact of an aircraft on the facility. In this work, a safety assessment analysis for the case of an aircraft crash into an interim storage facility is tackled. To this aim a methodology, based upon DOE, IAEA and NUREG standard procedures and upon conservative yet realistic hypothesis, has been developed in order to evaluate the total radioactivity, source term, released to the biosphere in consequence of the impact, without recurring to the use of complicated numerical codes. The procedure consists in the identification of the accidental scenarios, in the evaluation of the consequent damage to the building structures and to the waste packages and in the determination of the total release of radionuclides through the building-atmosphere interface. The methodology here developed has been applied to the case of an aircraft crash into an interim storage facility currently under design. Results show that in case of perforation followed by a fire incident the total released activity would be greater of some orders of magnitude with respect to the case of mere perforation. (author)

  17. Estimation of radionuclide releases in atmosphere from Cernavoda NPP based on continuous gaseous effluent monitoring

    International Nuclear Information System (INIS)

    Bobric, E.; Murgoci, S.; Popescu, I.; Ibadula, R.

    2001-01-01

    Monitoring of gaseous effluents from Cernavoda NPP is performed to assess the environmental impact of the plant operation. The results of the monitoring program are used to evaluate the population doses in order to ensure that the emissions of radionuclides in air are below regulatory limits and radiation doses are maintained ALARA. It complements, but is independent from the Operational Environmental Monitoring Program for Cernavoda NPP. Gaseous effluent monitors provide continuous indication of the radioactivity content in atmospheric emissions. Except for noble gases, these monitors also collect samples for later detailed analysis in the station Health Physics Laboratory. This paper presents the main equipment and the results of the gaseous effluents monitoring program in order to assess the impact of Cernavoda NPP operation and to predict the future releases as function of radionuclides concentrations in CANDU systems, based on the identified trends.(author)

  18. Inverse modelling of radionuclide release rates using gamma dose rate observations

    Science.gov (United States)

    Hamburger, Thomas; Evangeliou, Nikolaos; Stohl, Andreas; von Haustein, Christoph; Thummerer, Severin; Wallner, Christian

    2015-04-01

    Severe accidents in nuclear power plants such as the historical accident in Chernobyl 1986 or the more recent disaster in the Fukushima Dai-ichi nuclear power plant in 2011 have drastic impacts on the population and environment. Observations and dispersion modelling of the released radionuclides help to assess the regional impact of such nuclear accidents. Modelling the increase of regional radionuclide activity concentrations, which results from nuclear accidents, underlies a multiplicity of uncertainties. One of the most significant uncertainties is the estimation of the source term. That is, the time dependent quantification of the released spectrum of radionuclides during the course of the nuclear accident. The quantification of the source term may either remain uncertain (e.g. Chernobyl, Devell et al., 1995) or rely on estimates given by the operators of the nuclear power plant. Precise measurements are mostly missing due to practical limitations during the accident. The release rates of radionuclides at the accident site can be estimated using inverse modelling (Davoine and Bocquet, 2007). The accuracy of the method depends amongst others on the availability, reliability and the resolution in time and space of the used observations. Radionuclide activity concentrations are observed on a relatively sparse grid and the temporal resolution of available data may be low within the order of hours or a day. Gamma dose rates, on the other hand, are observed routinely on a much denser grid and higher temporal resolution and provide therefore a wider basis for inverse modelling (Saunier et al., 2013). We present a new inversion approach, which combines an atmospheric dispersion model and observations of radionuclide activity concentrations and gamma dose rates to obtain the source term of radionuclides. We use the Lagrangian particle dispersion model FLEXPART (Stohl et al., 1998; Stohl et al., 2005) to model the atmospheric transport of the released radionuclides. The

  19. Biosphere assessment due to radionuclide release in waste disposal repository through food chain pathways

    International Nuclear Information System (INIS)

    Ko, H. S.; Kang, C. S.

    2000-01-01

    The long-term safety of radioactive waste disposal is assessed by the consequence analysis of radionuclides release, of which the final step is carried out by the biosphere assessment. the radiation dose is calculated from the food chain modeling which especially necessitates site-specific input database and exposure pathways. A biosphere model in consideration of new exposure pathways has been analyzed, and a program for food chain calculation has been developed. The up-to-data input data are reflected and the new exposure pathways are considered in the program, so the code shows more realistic and reliable results

  20. Investigation of radionuclide release from Solid Waste Disposal Area 3, Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Stueber, A.M.; Webster, D.A.; Munro, I.L.; Farrow, N.D.; Scott, T.G.

    1981-08-01

    Radionuclide release from Solid Waste Disposal Area (SWDA) 3 has been studied through the analysis of surface and ground waters from the local drainage areas. SWDA 3 is located in the Northwest Tributary drainage basin, a part of the White Oak Creek drainage; 90 Sr is the only radionuclide being discharged in solution in the main stream. Water-level measurements in wells around SWDA 3 suggest the presence of a ground-water divide beneath the southwestern end of the disposal area. Ground water below this area may be moving southwestward toward the Raccoon Creek drainage system. Strontium-90 activity has been detected in this watershed, discharging from a seep adjacent to a Raccoon Creek tributary stream about 640 m southwest of SWDA 3. It appears that 90 Sr is moving through ground-water flow to the northeast and to the southwest of SWDA 3 and that this direction of movement is related to bedrock structure. The trend of a line connecting the two seeps passes through the disposal area and is parallel to bedrock strike. Information from core-hole logs and televiewer logs suggests that 90 Sr in ground water may be moving through solution channels near the contact between units F and G of the Chickamauga Limestone. The apparent extent of migration of 90 Sr in bedrock has implications regarding potential underground radionuclide movement in Melton Valley

  1. A comparison of measured radionuclide release rates from Three Mile Island Unit-2 core debris for different oxygen chemical potentials

    International Nuclear Information System (INIS)

    Baston, V.F.; Hofstetter, K.J.; Ryan, R.F.

    1987-01-01

    Chemical and radiochemical analyses of reactor coolant samples taken during defueling of the Three Mile Island Unit-2 (TMI-2) reactor provide relevant data to assist in understanding the solution chemistry of the radionuclides retained within the TMI-2 reactor coolant system. Hydrogen peroxide was added to various plant systems to provide disinfection for microbial contamination and has provided the opportunity to observe radionuclide release under different oxygen chemical potentials. A comparison of the radionuclide release rates with and without hydrogen peroxide has been made for these separate but related cases, i.e., the fuel transfer canal and connecting spent-fuel pool A with the TMI-2 reactor plenum in the fuel transfer canal, core debris grab sample laboratory experiments, and the reactor vessel fluid and associated core debris. Correlation and comparison of these data indicate a physical parameter dependence (surface-to-volume ratio) affecting all radionuclide release; however, selected radionuclides also demonstrate a chemical dependence release under the different oxygen chemical potentials. Chemical and radiochemical analyses of reactor coolant samples taken during defueling of the Three Mile Island Unit-2 (TMI-2) reactor provide relevant data to assist in understanding the solution chemistry of the radionuclides retained within the TMI-2 reactor coolant system

  2. Consideration for modelling studies of migration of accidentally released radionuclides in a river watershed

    International Nuclear Information System (INIS)

    Matsunaga, Takeshi; Tsuduki, Katsunori; Yanase, Nobuyuki; Hanzawa, Yukiko; Ueno, Takashi

    2004-01-01

    Concerning radionuclides that might be released in an event of an accident from a nuclear facility, much attention has been paid to the migration pathways including the atmospheric deposition and subsequent inflow to surface water bodies since the Chernobyl nuclear accident in 1986. In European countries, computer-coded systems for predicting the migration including those pathways and providing scientific supports for decision makers to manage the contamination have been developed. This report is a summary of presentations and discussion made at the occasion of the visit of Dr. Monte in order to have directions related to the current subject of research, development of a mathematical model of the behavior of radionuclides in a river watershed. Those presentations and discussions were made at JAERI and also at prominent universities and institutes of Japan involved in this study field. As a result of these discussions, distinct advantages and key issues in use of a mathematical model for prediction of the migration of radionuclides in a river watershed have been identified and analyzed. It was confirmed that the use of mathematical modeling has distinct advantages. Re-arrangement of the existing experimental knowledge on the environment in an ordered way according to a theory (a mathematical model) will lead to a new angle to consider a problem in that environment, despite several gaps in the data array. A model to assess the radionuclide behaviour in contaminated aquatic ecosystems is a basis of decision analysis tools for helping decision-makers to select the most appropriate intervention strategies for the ecosystems. Practical use of a mathematical model and continuous effort in its validation were recognized as crucial. (author)

  3. TURVA-2012: Assessment of radionuclide release scenarios for the repository system

    International Nuclear Information System (INIS)

    Smith, Paul; Poteri, Antti; Nordman, Henrik; Cormenzana, Jose Luis; Snellman, Margit; Marcos, Nuria; Hjerpe, Thomas; Koskinen, Lasse

    2014-01-01

    TURVA-2012 is Posiva's safety case in support of the Preliminary Safety Analysis Report (PSAR) and application for a construction licence for a repository for disposal of spent nuclear fuel at the Olkiluoto site in south-western Finland. This paper gives a summary of the analyses of the radionuclide release scenarios formulated in a companion paper, TURVA-2012: Formulation of Radionuclide Release Scenarios (Marcos, 2014). The scenarios and the analyses take into account major uncertainties in the initial state of the barriers and possible paths for the evolution of the repository system identified in a further paper: TURVA-2012: Performance Assessment (Hellae, 2014). For each scenario, calculation cases are analysed to evaluate compliance of the proposed repository with regulatory requirements on radiological protection, as well as to illustrate the impact of specific uncertainties or combinations of uncertainties on the calculated results. Each case illustrates different possibilities for how the repository might evolve and perform over time, taking into account uncertainties in the models and parameter values used to represent radionuclide release, retention and transport and, for biosphere assessment calculation cases, radiation exposure. The calculation cases each address a single, failed canister, where three possible modes of failure are considered: - The presence of an initial defect in the copper overpack of the canister that penetrates the overpack completely (subsequent corrosion of the insert may then lead to an enlargement of the defect). - Corrosion of the copper overpack, which occurs most rapidly in scenarios in which buffer density is reduced, e.g. by erosion. - Shear movements on fractures intersecting the deposition holes. However, the likelihood and consequences of more than one canister failure occurring during the assessment time fame are also considered, generally based on the findings from the single canister calculations. Quantitative

  4. Gas generation in SFL 3-5 and effects on radionuclide release

    Energy Technology Data Exchange (ETDEWEB)

    Skagius, K.; Lindgren, M.; Pers, K. [Kemakta Konsult AB, Stockholm (Sweden)

    1999-12-01

    A deep repository, SFL 3-5, is presently planned for disposing of long-lived low- and intermediate-level waste. In this study the amounts of gas that can be generated in the waste packages and in the vaults are estimated. The potential gas pressure build-up, the displacement of contaminated water and the consequences on radionuclide release from the engineered barriers in the repository are also addressed. The study is focussed on the repository design and waste inventory that was defined for the prestudy of SFL 3-5. Since the reporting of the prestudy the design of the repository has been modified and the waste inventory has been updated and a preliminary safety assessment of the repository has been carried outbased on the new design and updated waste inventory. The implications on gas generation and release of these modifications in design and waste inventory are briefly addressed in this study.

  5. Gas generation in SFL 3-5 and effects on radionuclide release

    International Nuclear Information System (INIS)

    Skagius, K.; Lindgren, M.; Pers, K.

    1999-12-01

    A deep repository, SFL 3-5, is presently planned for disposing of long-lived low- and intermediate-level waste. In this study the amounts of gas that can be generated in the waste packages and in the vaults are estimated. The potential gas pressure build-up, the displacement of contaminated water and the consequences on radionuclide release from the engineered barriers in the repository are also addressed. The study is focussed on the repository design and waste inventory that was defined for the prestudy of SFL 3-5. Since the reporting of the prestudy the design of the repository has been modified and the waste inventory has been updated and a preliminary safety assessment of the repository has been carried out based on the new design and updated waste inventory. The implications on gas generation and release of these modifications in design and waste inventory are briefly addressed in this study

  6. Pathways and estimated consequences of radionuclide releases from a nuclear power plant

    International Nuclear Information System (INIS)

    Nilsson, Mats.

    1981-03-01

    The radioactive corrosion products 60 Co, 58 Co, 54 Mn, 65 Zn, 51 Cr and 110 Agsp(m) which are released from Barsebaeck Nuclear Power Plant (Sweden) into the marine environment have been studied. The brown seaweed Fucus vesiculosus has been found to be excellent bioindicator for these radionuclides. The distribution of activation products along the west coast of Sweden has been studied and can very well be described with a power function. Uptake and retention of the activation products in Fucus have been studied and results are reported. The activity concentration in Fucus well reflects the disharge rate from the power plant. Other bioindicators have been studied ; mainly the crustaceans Idothea and Gammarus. A simulation of 131 I-release following a fictious BWR 1 accident is described as well as a model for estimation of the individual and collective dose equivalents arising from intake of contaminated milk. (Author)

  7. Global collective dose commitments from release of long-lived radionuclides. Differential cost-benefit considerations

    International Nuclear Information System (INIS)

    Gjoerup, H.L.

    1977-01-01

    The concept of global collective dose commitment as a measure of total detriment from the release of radioactivity to the environment is outlined. Estimates are given of global collective dose commitments resulting from the release of 14 C and uranium daughter products from the nuclear fuel cycle. Comparisons are made with similar estimates of global collective dose commitments resulting from the use of fossil fuels and certain fertilizers due to their content of uranium and its daughter products. In the case of long-lived radionuclides that remain in circulation in the biosphere, it is shown that the use of global collective dose commitments in differential cost-benefit analysis can lead to questionable results. In differential cost-benefit analysis it is suggested that population exposures should not simply be integrated irrespective of their time of occurrence, but that a certain discount rate should be applied for future doses. This suggestion is examined. (author)

  8. Radionuclide release rate inversion of nuclear accidents in nuclear facility based on Kalman filter

    International Nuclear Information System (INIS)

    Tang Xiuhuan; Bao Lihong; Li Hua; Wan Junsheng

    2014-01-01

    The rapidly and continually back-calculating source term is important for nuclear emergency response. The Gaussian multi-puff atmospheric dispersion model was used to produce regional environment monitoring data virtually, and then a Kalman filter was designed to inverse radionuclide release rate of nuclear accidents in nuclear facility and the release rate tracking in real time was achieved. The results show that the Kalman filter combined with Gaussian multi-puff atmospheric dispersion model can successfully track the virtually stable, linear or nonlinear release rate after being iterated about 10 times. The standard error of inversion results increases with the true value. Meanwhile extended Kalman filter cannot inverse the height parameter of accident release as interceptive error is too large to converge. Kalman filter constructed from environment monitoring data and Gaussian multi-puff atmospheric dispersion model can be applied to source inversion in nuclear accident which is characterized by static height and position, short and continual release in nuclear facility. Hence it turns out to be an alternative source inversion method in nuclear emergency response. (authors)

  9. The influence of site on the impact of radionuclides released into the marine environment

    International Nuclear Information System (INIS)

    Lochard, J.; Maccia, C.; Pages, P.

    1981-01-01

    The potential health impact of releases into the sea from a nuclear facility in normal operation is evaluated in two stages. First the concentration in sea water is determined by means of an area dispersion model which makes it possible to calculate the contamination of marine products (fish, crustaceans and molluscs) in the various areas. Then allowance is made for exchanges between the fishing zones and the regions where the products are consumed in order to estimate the collective radiological detriment on the regional level. The dispersion model was first applied to releases of 137 Cs which occurred during the 1969-1976 period in areas of the eastern English Channel and the eastern Irish Sea. Good agreement is observed with the measurements performed in 1976. The significance of site parameters is then demonstrated by comparing the evolution of concentrations after unit releases of 137 Cs and 239 Pu spread over one year. Depending on the radionuclide and the area where the release takes place, preponderant dilution effects (exchanges between areas) and/or sedimentation effects are observed. After presenting the method of calculating ingested activities, the main results for France are given, showing the impact of 137 Cs releases from a nuclear power station using Pressurized Water Reactors (4x1300 MW(e)) over a period of one year. (author)

  10. Characterization of a Planetary Boundary Layer model to evaluate radionuclides releases in nuclear installations

    International Nuclear Information System (INIS)

    Molnary, Leslie de

    1993-01-01

    A two layer bulk model is used to simulate numerically the time and spatial evolution of concentration of radionuclides in the Planetary Boundary Layer (PBL) for convective and stable conditions. In this model, the closure hypothesis are based on the integrated version of the Turbulent Kinetics Energy (TKE) equation (Smeda,1979). This type of model was adopted here because it is numerically simple to be applied operationally in routine and emergency support systems of atmospheric releases at nuclear power plants, and the hypothesis of the efficiency of the vertical mixing seems to be physically reasonable to simulated PBL evolution for high wind conditions and stable conditions in Subtropical latitudes regions. In order to validate the model to the nuclear power plants of the Centro Experimental Aramar (CEA), located in Ipero, State of Sao Paulo, Brazil, numerical simulations were carried out with initial and boundary conditions based on vertical profiles of temperature and horizontal wind speed and direction obtained from tethered balloon soundings, synoptic charts at 850 hPa and surface observations. Comparisons between a 24 hour long numerical simulation and observations indicate that the model is capable of reproduce the diurnal evolution of temperature and horizontal wind during the convective regime. During stable conditions, the slab model was able to simulate the intensity of the surface inversion as a difference between the mixed layer and surface temperatures. The simulated mixed layer height matches with observations during the convective and stable regime. A daytime release of radionuclides was simulated for CEA region and the results indicated that the maximum relative concentration reaches a distance about 15 Km in 1 hour, varing from 100 times background at the moment of the release to 15 times the background. For night releases, the maximum concentration reaches the same distance in 45 minutes, varing from 100 to 30 times the background values

  11. UFOING: A program for assessing the off-site consequences from ingestion of accidentally released radionuclides

    International Nuclear Information System (INIS)

    Steinhauer, C.

    1988-12-01

    The program UFOING estimates foodchain-related consequences following accidental releases of radionuclides to the atmosphere. It was developed as a stand-alone supplement to the accident consequence assessment program system UFOMOD to allow faster and more detailed investigations of the consequences arising from the foodchain pathways than possible with the version of UFOING which is implemented in UFOMOD. For assumed releases at different times of the year, age dependent individual doses, collective doses, individual risks for fatal stochastic somatic health effects as a function of time, the total numbers of the effects, and the areas affected by foodbans together with the estimated duration of the bans are calculated. In addition, percentage contributions of radionuclides and foodstuffs to the doses and risks can be evaluated. In the first part of this report, an overview over the program is given. The other parts contain a user's guide, a program guide, and descriptions of the data employed and of the version of UFOING which is implemented in UFOMOD. (orig.) [de

  12. A review of radionuclide release and transport in recent in-pile experiments

    International Nuclear Information System (INIS)

    Harman, N.F.; Clough, P.N.

    1992-01-01

    The experimental series, reviewed in this work, are LOFT-LP-FP-2, PBF SFD ST to 1-4, Treat/STEP I to 4, and ACRR ST-1 and ST-2. These have the common features of in-core heating of a test fuel bundle to high temperatures (usually with some fuel melting) in an experimental reactor core, and of collecting and analysing the released fission products. They were designed to provide detailed information on the release from fuel of fission products and other radionuclides under LWR severe accident conditions, and on the chemical and physical forms and transport of the fission products. The main aim of this review is to bring together, in a systematic way, information on the conduct of the tests, on their successes and failures, and particularly on the information they generated on the chemical and physical behaviour of released fission products. By examining and analysing the data from all of the tests together, patterns of fission product behaviour may become apparent and insights may be gained, which would not be arrived at from individual test results. Moreover, important lessons may be learned, and useful guidance obtained, relating to the aims and conduct of future experimental programmes of fission product release from fuel and transport behaviour. The conclusions should be particularly relevant to the imminent Phebus-FP in-pile test series at Cadarache

  13. Controlled-release tablet formulation of isoniazid.

    Science.gov (United States)

    Jain, N K; Kulkarni, K; Talwar, N

    1992-04-01

    Guar (GG) and Karaya gums (KG) alone and in combination with hydroxy-propylmethylcellulose (HPMC) were evaluated as release retarding materials to formulate a controlled-release tablet dosage form of isoniazid (1). In vitro release of 1 from tablets followed non-Fickian release profile with rapid initial release. Urinary excretion studies in normal subjects showed steady-state levels of 1 for 13 h. In vitro and in vivo data correlated (r = 0.9794). The studies suggested the potentiality of GG and KG as release retarding materials in formulating controlled-release tablet dosage forms of 1.

  14. Radionuclide transport in fractured rock: quantifying releases from final disposal of high level waste

    International Nuclear Information System (INIS)

    Silveira, Claudia S. da; Alvim, Antonio C.M.

    2013-01-01

    Crystalline rock has been considered as a potentially suitable matrix for high-level radioactive waste (HLW) repository because it is found in very stable geological formations and may have very low permeability. In this study the adopted physical system consists of the rock matrix containing a discrete horizontal fracture in a water saturated porous rock and a system of vertical fractures as a lineament. The transport in the fractures - horizontal and vertical, is assumed to obey a relation convection-diffusion, while the molecular diffusion is considered dominant mechanism of transport in porous rock. In this model the decay chain is considered. We use a code in Fortran 90, where the partial differential equations that describe the movement of radionuclides were discretized by finite differences methods. We use the fully implicit method for temporal discretization schemes. The simulation was performed with relevant data of nuclides in spent fuel for performance assessment in a hypothetical repository, thus quantifying the radionuclides released into the host rock. (author)

  15. Evaluation of radionuclide releases from underground waste repositories using the method of status vectors

    International Nuclear Information System (INIS)

    Zappe, D.

    1983-01-01

    For safety analyses of underground repositories for radioactive wastes various possible release scenarios have to be defind and anticipated consequences to be calculated and compared. Normally only the main exposure pathways (i.e. the critical pathways) of the radionuclides disposed of in the repository are calculated using deterministic methods and varying the parameters. It is proposed to evaluate all the individual pathways including those differing considerably from the critical pathway by forming weighted averages of their consequences. This offers the possibility of including, without any restriction, in the evaluation of the repository the various possible events and processes that influence the function of barriers for the retention of radionuclides. Various states (scenarios) of a repository in a salt formation, which might occur in the course of time have been used as an example. The consequences related to these states and the probabilities of their occurrence or the scenario weights form the components of 'status vectors'. For low- and intermediate-level wastes the overall consequences obtained from these calculations are negligibly small, for high-level wastes they are about 3 x 10 - 5 Sv a - 1 /GW a. These values are reached if at least a part of the barriers is effective. Variations of the weighting factors for the states and their influence on the overall consequences are given. (author)

  16. Radionuclides for process control and inspection

    International Nuclear Information System (INIS)

    Hadden, R.J.B.

    1987-01-01

    Radiation sources have been used in process control for over 40 years. Their use in inspection, implying visual examination, although of much earlier origin in the form of gamma radiography, is also of recent emergence in the form of tomographic methods. This paper firstly reviews the justification for the continued world-wide usage of isotopic methods. It then reviews a selection of innovative process control applications, based on radiation sources, as illustrations of the present state of the art and also describes recent progress in inspection methods including progress in the development of on-line facilities. For all applications involving radiation sources, careful selection of parameters is required to achieve the highest efficiency compatible with an integrity suitable for the intended application. The paper concludes with a brief discussion of the common principles on which the fabrication of sources is based in order to satisfy national and international safety legislation. (author)

  17. Assessment of an accidental fuel radionuclide release data from the damaged Chernobyl NPP unit 4

    International Nuclear Information System (INIS)

    Mikhajlov, O.V.; Doroshenko, A.O.

    2015-01-01

    A procedure and results of assessment of fuel temperature dynamics during the formation of lava-like fuel containing materials (LFCM) in room 305/2 are presented. The assessment of the overheated fuel temperature carried out using mathematical type codes CORSOR's type from the known radionuclide release data in the period from 26.04 to 11.05.86. It is shown that the main LFCM's accumulations could be formed at a moderate value of temperatures than previously estimated. The obtained data were used to verify the ''blast furnace'' version of LFCM formation and formation of FCM with high uranium concentration and temperature of the core fragment's charge

  18. Outline of UNSCEAR 2013 report (1). Radionuclide releases, dispersion and deposition

    International Nuclear Information System (INIS)

    Nagai, Haruyasu; Kurihara, Osamu

    2014-01-01

    The general assembly of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) was held in May, 2013 and the influence of the TEPCO Fukushima Daiichi nuclear power station accident on the environment and the human body, which has been analyzed and discussed by many specialists, was reported. The detailed contents of the influence were published in April, 2014 as the UNSCEAR 2013 Report (Vol. I: Report of the UNSCEAR to the General Assembly; Scientific Annex A: Levels and effects of radiation exposure due to the nuclear accident after the 2011 great east-Japan earthquake and tsunami and Vol. II: Scientific Findings on Effects of Radiation Exposure of Children; Scientific Annex B: Effects of radiation exposure of children). In the present paper, the outlines of the Scientific Annex A and the chapter III (Radionuclide releases, dispersion and deposition) in it are described. (K. Kato)

  19. Field studies of the atmospheric processing of radionuclides released at Chernobyl

    International Nuclear Information System (INIS)

    Slinn, W.G.N.; Brodzinski, R.L.; Busness, K.M.

    1987-01-01

    This report gives a summary description of the goals and execution of field studies to characterize the radionuclides released from Chernobyl and to examine their long-range atmospheric transport and processing. Starting on April 28, 1986, an intensive planning and preparation effort was mounted over a very short time intercept and characterize the Chernobyl plume on its arrival over the western US. During the execution of these studies, they had very little firm information (beyond their own measurements and trajectory estimates) to confirm the location of the Chernobyl plume. On May 20, 1986, the studies were terminated, after extensive airborne sampling of air, cloud water, precipitation, soil, and vegetation as the plume traversed the western and central US and moved into Canada

  20. Report of the consultant's meeting on monitoring accidentally released radionuclides in the environment

    International Nuclear Information System (INIS)

    2001-01-01

    At an earlier Research Co-ordination Meeting (12-16 August 1991, VIC, Vienna) for the IAEA Programme on 'Rapid Instrumental and Separation Methods for Monitoring Radionuclides in Food and Environmental Samples', it was recognized that a network of analytical laboratories with specially qualified scientists is needed which will provide a timely coordinated response to any future requests for assistance from Member States. The experience gained from the International Chernobyl Project revealed that there is a need for such a closely linked group when the Member State lacks sufficient technical resource to independently perform an assessment of environmental contamination following an accidental release of radioactivity. The existence of such a network of laboratories would help to assure responsible government representatives and the general public that the Agency has additional available resources including specialized experts to perform assessments on which to base required actions for many accident scenarios and their radiological consequences. The purpose of the present Consultants' Meeting is to discuss the organization and scope of the proposed network of analytical laboratories. The Consultants should discuss the matrices and nuclides of interest at various time frames of an accidental release of radioactivity. It is also intended that the Consultants should discuss the laboratories from their experience which would have the specialized expertise needed, in both terrestrial and aquatic sample collection and analysis. Finally, it is intended that the Consultants should discuss whether it would be desirable for the Agency to produce a technical document based on the achievements of the Agency programme on 'Rapid Instrumental and Separation Methods for Monitoring Radionuclides in Food and Environmental Samples'. A Guide Book was considered essential by the participants of this Co-ordinated Research Programme because it would be a succinct form and on a common

  1. Model to estimate radiation dose commitments to the world population from the atmospheric release of radionuclides (LWBR development program)

    International Nuclear Information System (INIS)

    Rider, J.L.; Beal, S.K.

    1978-02-01

    The equations developed for use in the LWBR environmental statement to estimate the dose commitment over a given time interval to a given organ of the population in the entire region affected by the atmospheric releases of a radionuclide are presented and may be used for any assessment of dose commitments in these regions. These equations define the dose commitments to the world resulting from a released radionuclide and each of its daughters and the sum of these dose commitments provides the total dose commitment accrued from the release of a given radionuclide. If more than one radionuclide is released from a facility, then the sum of the dose commitments from each released nuclide and from each daughter of each released nuclide is the total dose commitment to the world from that facility. Furthermore, if more than one facility is considered as part of an industry, then the sum of the dose commitments from the individual facilities represents the total world dose commitment associated with that industry. The actual solutions to these equations are carried out by the AIRWAY computer program. The writing of this computer program entailed defining in detail the specific representations of the various parameters such as scavenging coefficients, resuspension factors, deposition velocities, dose commitment conversion factors, and food uptake factors, in addition to providing specific numerical values for these types of parameters. The program permits the examination of more than one released nuclide at a time and performs the necessary summing to obtain the total dose commitment to the world accrued from the specified releases

  2. Retrospective estimation of middle irradiation doses for population of south Ukraine from radionuclides of Chernobyl accidental release

    International Nuclear Information System (INIS)

    Grigor'jeva, L.Yi.; Grigor'jev, K.V.

    2011-01-01

    The results of retrospective definition of the radiation load to the population of south Ukraine the under abnormal condition Chernobyl release of radionuclide, executed from data of aerophare, spectrometry and dosimetric researches on territory Nikolaev, Odessa, Kirovograd areas and Autonomous Republic of Crimea, conducted by the Nikolaev research laboratory ''Larani'' in 1986 and in subsequent years are presented in the article.

  3. Advice concerning radionuclide release of nuclear power plants and public health

    International Nuclear Information System (INIS)

    1984-01-01

    Amongst the severe accidents with nuclear power plants, a number of scenario's is theoretically possible. These scenario's lead to more or less serious consequences for the environment. Characteristics for the category of accidents was the early breakdown of the containment of the reactor. In recent years more and more doubt has risen with regard to the most serious scenario KE. In the Netherlands the Committee for Reactor Safety (CRV) has reported on this subject (annex 1). According to the CRV the release of a number of important radionuclides, in the case of scenario KE, will be very much less than was supposed in the past. Also, the nuclides will be released much later than was supposed before. A committee of the Dutch Health Council, starting from the CRV-report, has made calculations on the radiological consequences of the KE-scenario, corrected in accordance with these new developments (KEH). As could be expected, this category KEH proves to be considerably less dangerous than was supposed before. Irradiation of the surrounding population with a lethal dose would not occur anymore. The number of somatic and genetic effects would be very small. The conclusions drawn from these calculations are given. These results are compared with calculated consequences of an accident of the KM-category. The CRV has defined a maximised accident from this category (KMM). The report includes the report of the Dutch Commission on Reactor Safety (CR-82-71) as an appendix. (Auth.)

  4. Operation and maintenance manuals for VEGA apparatus on radionuclide release from irradiated fuel

    International Nuclear Information System (INIS)

    Hayashida, Retsu; Hidaka, Akihide; Nakamura, Takehiko; Kudo, Tamotsu; Ohtomo, Takashi; Uetsuka, Hiroshi

    2001-03-01

    An experimental program, Verification Experiments of radionuclides Gas/Aerosol release (VEGA), was initiated at JAERI from September 1999 to improve source term predictabilities for hypothetical severe accidents. In the experiment, a short fuel segment taken from LWR fuels irradiated in Japanese power reactors is inductively heated to high temperatures (∼3273K) in a hot cell under high pressure conditions up to 1.0MPa. Particularly, a focus will be placed on the release and transport behaviors of low-volatile fission products (FP), actinides and short-life FP which have not been well investigated in previous studies. This experimental apparatus was completed in February 1999 and three experiments were performed by the end of 2000. Most of these experiments were successfully conducted, but some problems were also found. Especially, in the first VEGA-1 test with the purpose of shakedown and reference data acquisition, there were problems such as flow blockage at the outlet of furnace due to structure melting, malfunction of heaters and so on. Therefore, the design for these defective parts was changed for future experiments. Moreover, the apparatus is not so big but the entire processes are very complicated. Accordingly, the operators should well understand the details of the apparatus including the recent change of design. This report describes outlines of the VEGA apparatus and the procedures for operation and maintenance. (author)

  5. Scenarios for potential radionuclide release from marine reactors dumped in the Kara Sea

    International Nuclear Information System (INIS)

    Lynn, N.; Mount, M.; Gussgard, K.

    1995-01-01

    The largest inventory of radioactive materials dumped in the Kara Sea by the former Soviet Union comes from the spent nuclear fuel (SNF) of seven marine reactors, the current (1994) inventory of which makes a total of approximately 4.7x10 15 Bq. In progressing its work for the International Arctic Seas Assessment Project, under the auspices of the International Atomic Energy Agency, the Source Term Working Group has analysed the Source Term and subsequently developed a number of model scenarios for the potential release patterns of radionuclides into the Kara Sea from the SNF and activated components dumped within the marine reactors.These models are based on the present and future conditions of the barrier materials and their configuration within the dumped objects. They account for progressive corrosion of the outer and inner steel barriers, breakdown of the organic fillers, and degradation and leaching from the SNFs. Annual release rates are predicted to four thousand years into the future. 5 refs., 1 fig., 1 tab

  6. Determination of the radionuclide release factor for an evaporator process using nondestructive assay

    International Nuclear Information System (INIS)

    Johnson, R.E.

    1998-01-01

    The 242-A Evaporator is the primary waste evaporator for the Hanford Site radioactive liquid waste stored in underground double-shell tanks. Low pressure evaporation is used to remove water from the waste, thus reducing the amount of tank space required for storage. The process produces a concentrated slurry, a process condensate, and an offgas. The offgas exhausts through two stages of high-efficiency particulate air (HEPA) filters before being discharged to the atmosphere 40 CFR 61 Subpart H requires assessment of the unfiltered exhaust to determine if continuous compliant sampling is required. Because potential (unfiltered) emissions are not measured, methods have been developed to estimate these emissions. One of the methods accepted by the Environmental Protection Agency is the measurement of the accumulation of radionuclides on the HEPA filters. Nondestructive assay (NDA) was selected for determining the accumulation on the HEPA filters. NDA was performed on the HEPA filters before and after a campaign in 1997. NDA results indicate that 2.1 E+4 becquerels of cesium-137 were accumulated on the primary HEPA 1700 filter during the campaign. The feed material processed in the campaign contained a total of 1.4 E+l6 Bq of cesium-137. The release factor for the evaporator process is 1.5 E-12. Based on this release factor, continuous compliant sampling is not required

  7. Safety case for the disposal of spent nuclear fuel at Olkiluoto. Formulation of radionuclide release scenarios 2012

    International Nuclear Information System (INIS)

    2013-04-01

    TURVA-2012 is Posiva's safety case in support of the Preliminary Safety Analysis Report (PSAR) and application for a construction licence for a repository for disposal of spent nuclear fuel at the Olkiluoto site in south-western Finland. This report presents the radionuclide release scenarios and the methodology followed in formulating them. The formulation of scenarios takes into account the regulatory framework, the knowledge acquired in the present safety case as well as in previous safety assessments, the safety functions of the barriers of the repository system and the uncertainties in the features, events, and processes (FEPs) that may affect the entire disposal system (i.e. repository system plus the surface environment) from the emplacement of the first canister until the far future. In the report Performance Assessment, the performance of the engineered and natural barriers has been assessed against the loads expected during the evolution of the repository system and the site. Uncertainties have been identified and these are taken into account in the formulation of radionuclide release scenarios. The uncertainties in the FEPs affecting the characteristics and evolution of the surface environment are taken into account in formulating the surface environment scenarios used ultimately for assessing radiation exposure. Formulating radionuclide release scenarios for the repository system links the reports Performance Assessment and Assessment of Radionuclide Release Scenarios for the Repository System. The formulation of radionuclide release scenarios for the surface environment brings together Biosphere Description and the surface environment FEPs and is the link to the assessment of the surface environment scenarios analysed in Biosphere Assessment. (orig.)

  8. Models for transport and fate of carbon, nutrients and point source released radionuclides to an aquatic ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Kumblad, Linda [Stockholm Univ. (Sweden). Dept. of Systems Ecology; Kautsky, Ulrik [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

    2004-09-01

    In this report three ecosystem models are described in terms of structure, initial data, and results. All models are dynamic, mass-balanced and describe the transport and fate of elements in an open aquatic ecosystem. The models are based on ecologically sound principles, provide model results with high resolution and transparency, and are constrained by the nutrient dynamics of the ecosystem itself. The processes driving the transport in all the models are both the biological processes such as primary production, consumption, respiration and excretion, and abiotic e.g. water exchange and air-sea exchange. The first model, the CNP-model, describes the distribution and fluxes of carbon and nutrients for the coastal ecosystem off Forsmark. The second model, the C-14 model, is an extension of the CNP-model and describes the transport and distribution of hypothetically released C-14 from the underground repository SFR-1 to the ecosystem above. The third model, the RN-model, is a generic radionuclide flow model that models the transport and distribution of radionuclides other than C-14 hypothetically discharged to the ecosystem. The model also analyses the importance of some radionuclide specific mechanisms for the radionuclide flow. The generic radionuclide model is also based on the CNP-model, but has radionuclide specific mechanisms connected to each compartment.

  9. Models for transport and fate of carbon, nutrients and point source released radionuclides to an aquatic ecosystem

    International Nuclear Information System (INIS)

    Kumblad, Linda

    2004-09-01

    In this report three ecosystem models are described in terms of structure, initial data, and results. All models are dynamic, mass-balanced and describe the transport and fate of elements in an open aquatic ecosystem. The models are based on ecologically sound principles, provide model results with high resolution and transparency, and are constrained by the nutrient dynamics of the ecosystem itself. The processes driving the transport in all the models are both the biological processes such as primary production, consumption, respiration and excretion, and abiotic e.g. water exchange and air-sea exchange. The first model, the CNP-model, describes the distribution and fluxes of carbon and nutrients for the coastal ecosystem off Forsmark. The second model, the C-14 model, is an extension of the CNP-model and describes the transport and distribution of hypothetically released C-14 from the underground repository SFR-1 to the ecosystem above. The third model, the RN-model, is a generic radionuclide flow model that models the transport and distribution of radionuclides other than C-14 hypothetically discharged to the ecosystem. The model also analyses the importance of some radionuclide specific mechanisms for the radionuclide flow. The generic radionuclide model is also based on the CNP-model, but has radionuclide specific mechanisms connected to each compartment

  10. Screening models for releases of radionuclides to atmosphere, surface water, and ground -- Work sheets

    International Nuclear Information System (INIS)

    1996-01-01

    Three levels of screening for the atmospheric transport pathways and two levels for surface water are presented. The ground has only one screening level. Level 1 is the simplest approach and incorporates a high degree of conservatism. The estimate of the effective dose for this level assumes a concentration based upon the radionuclide concentration at the point of emission to the environment, i.e., at the stack for atmospheric emissions, at the end of the effluent pipe for liquid effluent releases, and at a well because of the buried radioactive material. Levels 2 and 3 are presented for atmospheric releases, and Level 2 for surface water releases only and are more detailed and correspondingly less conservative. Level 2 screening accounts for dispersion in the atmosphere and in surface waters and combines all recognized pathways into the screening factor. For the atmospheric pathway, Level 3 screening includes more definitive pathways analysis. Should the user be found in compliance on the basis of Level 1 screening, no further calculations are required. If the user fails Level 1, the user proceeds to the next level and checks for compliance. This process is repeated until the user passes screening (is in compliance) or no further screening levels exist. If the user fails the final level, professional assistance should be obtained in environmental radiological assessment. Work sheets are designed to lead the user through screening in a step-by-step manner until compliance is demonstrated or it is determined that more sophisticated methods or expertise are needed. Flow diagrams are provided as a guide to identify key steps in the screening process

  11. Radionuclide release, transport, and consequence modeling for WIPP: a report of a workshop held on September 16-17, 1981

    International Nuclear Information System (INIS)

    1982-02-01

    The purpose of this workshop was to discuss potential mechanisms for release of radionuclides from the WIPP repository years after waste emplacement and termination of institutional controls, and the resultant radiological consequences. Opportunity was also provided for the exchange of information on meaningful release and transport models, and the availability, reliability and significance of data for the parameters applicable to those models. Other than those scenarios provided in draft by the Environmental Evaluation Group (EEG) (Appendix II), there were no new breach scenarios postulated. Also there were no major objections posed to the EEG proposals or the approaches taken in these drafts. Although there were no formal conclusions highlighted by the Conference, the EEG has concluded that the statements below provide a summary of EEG's views concerning the topics covered. These views are based upon the discussions at the Conference, the subsequent comments of the conferees, the information provided in the preceding EEG sponsored geological meeting and field trip, and the information contained in the EEG draft reports

  12. Application of two-barrier model of radioactive agent transport in sea water for analyzing artificial radionuclide release from containers with radioactive waste dumped in Kara Sea

    Energy Technology Data Exchange (ETDEWEB)

    Grishin, Denis S.; Laykin, Andrey I.; Kuchin, Nickolay L.; Platovskikh, Yuri A. [Krylov State Research Center, Saint Petersburg, 44 Moskovskoe shosse, 196158 (Russian Federation)

    2014-07-01

    Modeling of artificial radionuclide transport in sea water is crucial for prognosis of radioecological situation in regions where dumping of radioactive waste had been made and/or accidents with nuclear submarines had taken place. Distribution of artificial radionuclides in bottom sediments can be a detector of radionuclide release from dumped or sunk objects to marine environment. Proper model can determine the dependence between radionuclide distribution in sediments and radionuclide release. Following report describes two-barrier model of radioactive agent transport in sea water. It was tested on data from 1994 - 2013 expeditions to Novaya Zemlya bays, where regular dumping of solid radioactive waste was practiced by the former USSR from the early 1960's until 1990. Two-barrier model agrees with experimental data and allows more accurate determination of time and intensity of artificial radionuclide release from dumped containers. (authors)

  13. Estimates of radionuclide release from glass waste forms in a tuff repository and the effects on regulatory compliance

    International Nuclear Information System (INIS)

    Aines, R.D.

    1986-04-01

    This paper discusses preliminary estimates of the release of radionuclides from waste packages containing glass-based waste forms under the expected conditions at Yucca Mountain. These estimates can be used to evaluate the contribution of waste package performance toward meeting repository regulatory restrictions on radionuclide release. Glass waste will be held in double stainless steel canisters. After failure of the container sometime after the 300 to 1000 year containment period, the open headspace in these cans will provide the only area where standing water can accumulate and react with the glass. A maximum release rate of 0.177 g/m 2 x year or 1.3 grams per year was obtained. Normalized loss of 1.3 grams per year corresponds to 0.08 parts in 100,000 per year of the 1660 kg reference weight of DWPF glass

  14. Marine biogeochemistry of radionuclides

    International Nuclear Information System (INIS)

    Fowler, S.W.

    1997-01-01

    Radionuclides entering the ocean from runoff, fallout, or deliberate release rapidly become involved in marine biogeochemical cycles. Sources, sinks and transport of radionuclides and analogue elements are discussed with emphasis placed on how these elements interact with marine organisms. Water, food and sediments are the source terms from which marine biota acquire radionuclides. Uptake from water occurs by surface adsorption, absorption across body surfaces, or a combination of both. Radionuclides ingested with food are either assimilated into tissue or excreted. The relative importance of the food and water pathway in uptake varies with the radionuclide and the conditions under which exposure occurs. Evidence suggests that, compared to the water and food pathways, bioavailability of sediment-bound radionuclides is low. Bioaccumulation processes are controlled by many environmental and intrinsic factors including exposure time, physical-chemical form of the radionuclide, salinity, temperature, competitive effects with other elements, organism size, physiology, life cycle and feeding habits. Once accumulated, radionuclides are transported actively by vertical and horizontal movements of organisms and passively by release of biogenic products, e.g., soluble excreta, feces, molts and eggs. Through feeding activities, particles containing radionuclides are ''packaged'' into larger aggregates which are redistributed upon release. Most radionuclides are not irreversibly bound to such particles but are remineralized as they sink and/or decompose. In the pelagic zones, sinking aggregates can further scavenge particle-reactive elements thus removing them from the surface layers and transporting them to depth. Evidence from both radiotracer experiments and in situ sediment trap studies is presented which illustrates the importance of biological scavenging in controlling the distribution of radionuclides in the water column. (author)

  15. Release of iodine radionuclides from gas media in a system of selective block sorbents

    International Nuclear Information System (INIS)

    Moskvin, L.N.; Miroshnikov, V.S.; Mel'nikov, V.A.; Chetverikov, V.V.

    1979-01-01

    A scheme of extracting iodine radionuclides from gas flows in a system of selective sorbents has been developed. The method provides separation of three forms of iodine: the aerosol component, the elementary iodine and organic-iodine compounds. Aerosols are trapped by a mechanical filter made of porous polytetrafluoroethylene with pores of no more than 1 μm. Silver-based sorbents for the elementary iodine are made by sintering the granular polytetrafluoroethylene (the size of granules is 0.1-0.5 mm) with of finely dispersed solver (5% mass). Organic iodine compounds are extracted by a silica sorbent impregnated with silver nitrate. The efficiency of sorbents was tested in gas flows with a known content of 131 I in the form of elementary iodine and methyl iodide. The results of experiments show that the efficiency of sorption of elementary iodine by a metallic-silver sorbent and of methyl iodide by a SiO 2 /AgNO 3 sorbent constitutes no less than 99% at a flow rate of up to 200 l/h. The iodine has been extracted at a flow rate of 100 l/h during 100 hours and for that time the efficiency of the iodine sorbtion has not changed. The suggested variant of extracting iodine radionuclides from gaseous media can be used both for fast control of iodine content in gas blowoffs and for researches aimed at studying the distribution of iodine forms in steam-and-gas media depending on nuclear plant operating conditions

  16. Performance and quality control of radionuclide calibrators in nuclear medicine

    International Nuclear Information System (INIS)

    Woods, M.J.; Baker, M.

    2002-01-01

    Full text: The use of ionising radiations in nuclear medicine has traditionally divided itself into two specific areas. The diagnostic usage has generally been dominated by the injection or ingestion of radionuclides. The therapeutic applications, on the other hand, have usually been accomplished by the application of ionising radiation, both from machines and radionuclide sources, whereby the radiation source is external to the patient. Over recent years, this divide has become increasingly blurred and the science between diagnosis and therapy has become significantly closer. This is particularly the situation in respect of the instruments used to determine the activity or dose delivered by the radiation source. In the ideal therapeutic situation, the radiation dose would be delivered solely to the malignant tissue. With external radiation therapy, this can never be achieved completely but this ideal can be approached more closely with targeted radiotherapy wherein radionuclides are introduced directly into the malignancy either as a solid, physical source or as a solution that, by its chemistry, concentrates into the area of interest. In order to achieve the optimum efficacy of treatment, there is an associated requirement to determine accurately the activity or dose rate of the radioactive source being used. It is here that the technology used in the diagnostic field can also be used to advantage for therapeutic applications. For diagnosis, the instrument of choice is the radionuclide calibrator and this equipment is increasingly finding parallel usage for the characterisation of therapeutic sources. Despite their appearances however, radionuclide calibrators are not 'black boxes' and need to be used with care, subjected to a robust level of quality control and operated by personnel who have a fundamental understanding of their operational characteristics. A measure of the level of performance of operational radionuclide calibrators and the competence of their

  17. Probability of liquid radionuclide release of a near surface repository; Probabilidade de liberacao liquida de radionuclideos de um repositorio proximo a superficie

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Lais A.; Melo, P.F. Frutuoso e [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Nuclear]. E-mail: lais@con.ufrj.br; frutuoso@con.ufrj.br; Passos, Erivaldo; Alves, Antonio Sergio [ELETRONUCLEAR, Rio de Janeiro, RJ (Brazil). Div. de Seguranca Nuclear]. E-mail: epassos@eletronuclear.gov.br; asergi@eletronuclear.gov.br

    2005-07-01

    The safety analysis of a near surface repository for medium and low activity wastes leads to investigating accident scenarios related to water infiltration phenomena. The probability of radionuclide release through the infiltration water could be estimated with the aid of suitable probabilistic models. For the analysis, the repository system is divided into two subsystems: the first, due to the barriers against the water infiltration (backfill material and container), and the second one comprising the barriers against the leaching of radionuclide to the biosphere (solid matrix and geosphere). The repository system is supposed to have its components (barriers) working in an active parallel mode. The probability of the system failure is obtained from the logical structure of a failure tree. The study was based on the Probabilistic Safety Assessment (PSA) technique for the most significant radionuclides within the radioactive packages system of low and medium activity, and so the probability of failure of the system for each radionuclide during the time period of institutional control was obtained. (author)

  18. Stimuli responsive nanomaterials for controlled release applications

    KAUST Repository

    Li, Song

    2012-01-01

    The controlled release of therapeutics has been one of the major challenges for scientists and engineers during the past three decades. Coupled with excellent biocompatibility profiles, various nanomaterials have showed great promise for biomedical applications. Stimuli-responsive nanomaterials guarantee the controlled release of cargo to a given location, at a specific time, and with an accurate amount. In this review, we have combined the major stimuli that are currently used to achieve the ultimate goal of controlled and targeted release by "smart" nanomaterials. The most heavily explored strategies include (1) pH, (2) enzymes, (3) redox, (4) magnetic, and (5) light-triggered release.

  19. Lignin based controlled release coatings

    NARCIS (Netherlands)

    Mulder, W.J.; Gosselink, R.J.A.; Vingerhoeds, M.H.; Harmsen, P.F.H.; Eastham, D.

    2011-01-01

    Urea is a commonly used fertilizer. Due to its high water-solubility, misuse easily leads to excess nitrogen levels in the soil. The aim of this research was to develop an economically feasible and biodegradable slow-release coating for urea. For this purpose, lignin was selected as coating

  20. Controlled Release from Zein Matrices

    NARCIS (Netherlands)

    Bouman, Jacob; Belton, Peter; Venema, Paul; Linden, Van Der Erik; Vries, De Renko; Qi, Sheng

    2016-01-01

    Purpose: In earlier studies, the corn protein zein is found to be suitable as a sustained release agent, yet the range of drugs for which zein has been studied remains small. Here, zein is used as a sole excipient for drugs differing in hydrophobicity and isoelectric point: indomethacin,

  1. Evaluating the radiation environment around a nuclear power station with unmonitored radionuclide release

    International Nuclear Information System (INIS)

    Bondarev, A.A.; Dibobes, I.K.; Pyuskyulan, K.I.

    1986-01-01

    This paper describes the radiation monitoring system at (RMS) at the Armenian nuclear power station; the environmental monitoring program includes measuring the gamma radiation around the station, determining radionuclide contents in air and fallout, and also in surface water and ground water, in water plants and bottom sediments, in soil and plants and also in local agricultural products. The RMS monitors gas-aerosol releases and effluents from the station. The radius of the monitored zone is 25 km. The gamma radiation is measured by IKS dosemeters and SRP-68-01 portable instruments. The air is monitored by six stationary aspriation systems at distances of 1, 5, 6, 11, 14, 15 and 50 km and 28 planchette cells. The RMS records virtually all the mean monthly and mean annual fluctuations in the global background. In seven years of operation at the Armenian station, only Ca 137 and Sr 90 from global fallout together with Be 7 of cosmogenic origin have been observed in air apart from two cases. In 1981, air samples taken with the aspirators and combined over a quarter showed Ce 141, Ce 144, Ru 106, Ru 103, Nb 95 and Zr 95. The concentrations of these are presented

  2. Heat-pipe effect on the transport of gaseous radionuclides released from a nuclear waste container

    International Nuclear Information System (INIS)

    Zhou, W.; Chambre, P.L.; Pigford, T.H.; Lee, W.W.L.

    1990-11-01

    When an unsaturated porous medium is subjected to a temperature gradient and the temperature is sufficiently high, vadose water is heated and vaporizes. Vapor flows under its pressure gradient towards colder regions where it condenses. Vaporization and condensation produce a liquid saturation gradient, creating a capillary pressure gradient inside the porous medium. Condensate flows towards the hot end under the influence of a capillary pressure gradient. This is a heat pipe in an unsaturated porous medium. We study analytically the transport of gaseous species released from a spent-fuel waste package, as affected by a time-dependent heat pipe in an unsaturated rock. For parameter values typical of a potential repository in partially saturated fractured tuff at Yucca Mountain, we found that a heat pipe develops shortly after waste is buried, and the heat-pipe's spatial extent is time-dependent. Water vapor movements produced by the heat pipe can significantly affect the migration of gaseous radionuclides. 12 refs., 6 figs., 1 tab

  3. Technogenic radionuclides of Chernobyl NPP accidental release and their physical and chemical forms

    Directory of Open Access Journals (Sweden)

    A. I. Lypska

    2015-10-01

    Full Text Available Distribution of radionuclides in the vertical soil profile on the nearest Chernobyl NPP zone of alienation was investigated. It is showed experimentally that the main activity of radionuclides is concentrated in the topsoil (10 сm. Coefficients of accumulation of 137Cs and 90Sr radionuclides by plants are estimated. The physico-chemical forms of radionuclides in soil and plants were defined using the method of sequential chemical extraction. It was established that the main contents of 137Cs and 90Sr in soils are represented in non-exchange and fixed forms, in plants - mainly in exchange-adsorption and organic forms.

  4. Assessing the impact of releases of radionuclides into sewage systems in urban environment - simulation, modelling and experimental studies - LUCIA

    International Nuclear Information System (INIS)

    Sundelll-Bergman, S.; Avila, R.; Cruz, I. de la; Xu, S.; Puhakainen, M.; Heikkinene, T.; Rahola, T.; Hosseini, A.; Nielsen, Sven; Sigurgeirsson, M.

    2009-06-01

    This report summarises the findings of a project on assessing the impact of releases of radionuclides into sewage systems and was established to provide more knowledge and suitable tools for emergency preparedness purposes in urban areas. It was known that the design of sewage plants, and their wastewater treatments, is rather similar between the Nordic countries. One sewage plant in each of the five Nordic countries was selected for assessing the impact of radionuclide releases from hospitals into their sewerage systems. Measurements and model predictions of dose assessments to different potentially exposed members of the public were carried out. The results from the dose assessments indicate that in case of routine releases annual doses to the three hypothetical groups of individuals are most likely insignificant. Estimated doses for workers are below 10 μSv/y, for the two studied radionuclides 99mTc and 131I. If uncertainties in the predictions of activity concentrations in sludge are considered, then the probability of obtaining doses above 10 μSv/y may not be insignificant. The models and approaches developed can also be applied in case of accidental releases. A laboratory inter-comparison exercise was also organised to compare analytical results across the laboratories participating in the project, using both 131I, dominating man-made radionuclide in sewage systems due to the medical use. A process oriented model of the biological treatment is also proposed in the report that does not require as much input data as for the LUCIA model. This model is a combination of a simplified well known Activated Sludge Model No.1 (Henze, 1987) and the Kd concept used in the LUCIA model. The simplified model is able to estimate the concentrations and the retention time of the sludge in different parts of the treatment plant, which in turn, can be used as a tool for the dose assessment purpose.filled by the activity. (au)

  5. Assessing the impact of releases of radionuclides into sewage systems in urban environment - simulation, modelling and experimental studies - LUCIA

    Energy Technology Data Exchange (ETDEWEB)

    Sundelll-Bergman, S. (Vattenfall Power Consultant, Stockholm (Sweden)); Avila, R.; Cruz, I. de la (Facilia AB, (Sweden)); Xu, S. (Swedish Radiation Safety Authority, (Sweden)); Puhakainen, M.; Heikkinene, T.; Rahola, T. (STUK (Finland)); Hosseini, A. (Norwegian Radiation Protection Authority (Norway)); Nielsen, Sven (Risoe National Laboratory for Sustainable Energy, DTU (Denmark)); Sigurgeirsson, M. (Geislavarnir rikisins (Iceland))

    2009-06-15

    This report summarises the findings of a project on assessing the impact of releases of radionuclides into sewage systems and was established to provide more knowledge and suitable tools for emergency preparedness purposes in urban areas. It was known that the design of sewage plants, and their wastewater treatments, is rather similar between the Nordic countries. One sewage plant in each of the five Nordic countries was selected for assessing the impact of radionuclide releases from hospitals into their sewerage systems. Measurements and model predictions of dose assessments to different potentially exposed members of the public were carried out. The results from the dose assessments indicate that in case of routine releases annual doses to the three hypothetical groups of individuals are most likely insignificant. Estimated doses for workers are below 10 muSv/y, for the two studied radionuclides 99mTc and 131I. If uncertainties in the predictions of activity concentrations in sludge are considered, then the probability of obtaining doses above 10 muSv/y may not be insignificant. The models and approaches developed can also be applied in case of accidental releases. A laboratory inter-comparison exercise was also organised to compare analytical results across the laboratories participating in the project, using both 131I, dominating man-made radionuclide in sewage systems due to the medical use. A process oriented model of the biological treatment is also proposed in the report that does not require as much input data as for the LUCIA model. This model is a combination of a simplified well known Activated Sludge Model No.1 (Henze, 1987) and the Kd concept used in the LUCIA model. The simplified model is able to estimate the concentrations and the retention time of the sludge in different parts of the treatment plant, which in turn, can be used as a tool for the dose assessment purpose.filled by the activity. (au)

  6. Retrospective estimation of middle irraiation doses for population of south Ukraine from radionuclides of Chernobyl accidental release

    Directory of Open Access Journals (Sweden)

    L. I. Grygorieva

    2011-09-01

    Full Text Available The results of retrospective definition of the radiation load to the population of south Ukraine the under abnormal condition Chernobyl release of radionuclide, executed from data of aerophare, spectrometry and dosimetric researches on territory Nikolaev, Odessa, Kirovograd areas and Autonomous Republic of Crimea, conducted by the Nikolaev research laboratory “Larani” in 1986 and in subsequent years are presented in the article.

  7. Controlled drug release for tissue engineering.

    Science.gov (United States)

    Rambhia, Kunal J; Ma, Peter X

    2015-12-10

    Tissue engineering is often referred to as a three-pronged discipline, with each prong corresponding to 1) a 3D material matrix (scaffold), 2) drugs that act on molecular signaling, and 3) regenerative living cells. Herein we focus on reviewing advances in controlled release of drugs from tissue engineering platforms. This review addresses advances in hydrogels and porous scaffolds that are synthesized from natural materials and synthetic polymers for the purposes of controlled release in tissue engineering. We pay special attention to efforts to reduce the burst release effect and to provide sustained and long-term release. Finally, novel approaches to controlled release are described, including devices that allow for pulsatile and sequential delivery. In addition to recent advances, limitations of current approaches and areas of further research are discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. SKB WP-cave project. Radionuclide release from the near-field in a WP-cave repository

    International Nuclear Information System (INIS)

    Lindgren, M.; Skagius, K.

    1989-04-01

    The release of radionuclides from the bentonite-sand barrier (near-field) in a WP-cave repository for high level radioactive waste has been studied. Calculations were made for two cases; a Low Flow Through Case and a High Flow Through Case. The difference between the two cases lies in the assumed hydraulic properties of the bentonite-sand barrier and the system inside the barrier. The effect on the nuclide release of solubility limitations, sorption capacity of the barriers, radiolytic fuel oxidation rate as well as the thickness of the bentonite-sand barrier, were also investigated for the Low Flow Through Case. (authors)

  9. Emergency preparedness for the accidental release of radionuclides from the Uljin Nuclear Power Plant in Korea.

    Science.gov (United States)

    Park, Soon-Ung; Lee, In-Hye; Joo, Seung Jin; Ju, Jae-Won

    2017-12-01

    Site specific radionuclide dispersion databases were archived for the emergency response to the hypothetical releases of 137 Cs from the Uljin nuclear power plant in Korea. These databases were obtained with the horizontal resolution of 1.5 km in the local domain centered the power plant site by simulations of the Lagrangian Particle Dispersion Model (LPDM) with the Unified Model (UM)-Local Data Assimilation Prediction System (LDAPS). The Eulerian Dispersion Model-East Asia (EDM-EA) with the UM-Global Data Assimilation Prediction System (UM-GDAPS) meteorological models was used to get dispersion databases in the regional domain. The LPDM model was performed for a year with a 5-day interval yielding 72 synoptic time-scale cases in a year. For each case hourly mean near surface concentrations, hourly mean column integrated concentrations, hourly total depositions for 5 consecutive days were archived by the LPDM model in the local domain and by the EDM-EA model in the regional domain of Asia. Among 72 synoptic cases in a year the worst synoptic case that showed the highest mean surface concentration averaged for 5 days in the LPDM model domain was chosen to illustrate the emergency preparedness to the hypothetical accident at the site. The simulated results by the LPDM model with the 137 Cs emission rate of the Fukushima nuclear power plant accident for the first 5-day period were found to be able to provide prerequisite information for the emergency response to the early phase of the accident whereas those of the EDM-EA model could provide information required for the environmental impact assessment of the accident in the regional domain. The archived site-specific database of 72 synoptic cases in a year could have a great potential to be used as a prognostic information on the emergency preparedness for the early phase of accident. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Oceanographic model and radiological basis for control of radionuclide releases

    International Nuclear Information System (INIS)

    Hagen, A.A.

    1984-01-01

    Since it first prepared the provisional Definition of high-level radioactive waste unsuitable for dumping at sea and Recommendations for those radioactive wastes dumped under special permit in 1974, the IAEA has kept the Definition and Recommendations under continuing review. The oceanographic basis for the definition is being re-evaluated, based on a 1983 Report from the IMO/FAO/UNESCO/WMO/WHO/IAEA/UN/UNEP Joint Group of Experts on the Scientific Aspects of Marine Pollution (GESAMP), and the radiological basis is being updated, based on a Report from an IAEA Advisory Group Meeting held in 1982. The differences in the current radiological and oceanographic bases and the updating of both the GESAMP Report on modelling and the review of the radiological basis are delineated. In addition, a discussion of the future course of the Agency's activities in this area is given. (author)

  11. Subject-3: Study on migration of radionuclides released into terrestrial and aquatic environment after nuclear accident

    International Nuclear Information System (INIS)

    Amano, H.; Matsunaga, T.; Ueno, T.; Nagao, S.; Yanase, N.; Tkachenko, Yu.

    2001-01-01

    Subject-3 has been focused on the migration behavior of long-lived radionuclides in the terrestrial surface environment, especially in connection with their chemical and physical forms. Migration behavior of radionuclides is strongly affected with their chemical and physical forms (for example; Gunten and Benes 1995). One of the two categories in Subject-3 consists of migration from surface soils including aging effects of hot particles, plant uptake from contaminated soils, and resuspension of radionuclides. The other is run off by river system, considering the role of organic materials. (author)

  12. Subject-3: Study on migration of radionuclides released into terrestrial and aquatic environment after nuclear accident

    Energy Technology Data Exchange (ETDEWEB)

    Amano, H.; Matsunaga, T.; Ueno, T.; Nagao, S.; Yanase, N. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Arkhipov, A.N. [Chernobyl Scientific and Technical Center for International Research (Ukraine); Tkachenko, Yu. [The State Enterprise Regional Monitoring and Domestic Control (RADEC) (Unknown)

    2001-03-01

    Subject-3 has been focused on the migration behavior of long-lived radionuclides in the terrestrial surface environment, especially in connection with their chemical and physical forms. Migration behavior of radionuclides is strongly affected with their chemical and physical forms (for example; Gunten and Benes 1995). One of the two categories in Subject-3 consists of migration from surface soils including aging effects of hot particles, plant uptake from contaminated soils, and resuspension of radionuclides. The other is run off by river system, considering the role of organic materials. (author)

  13. Massive radiological releases profoundly differ from controlled releases

    International Nuclear Information System (INIS)

    Pascucci-Cahen, Ludivine; Patrick, Momal

    2012-11-01

    Preparing for a nuclear accident implies understanding potential consequences. While many specialized experts have been working on different particular aspects, surprisingly little effort has been dedicated to establishing the big picture and providing a global and balanced image of all major consequences. IRSN has been working on the cost of nuclear accidents, an exercise which must strive to be as comprehensive as possible since any omission obviously underestimates the cost. It therefore provides (ideally) an estimate of all cost components, thus revealing the structure of accident costs, and hence sketching a global picture. On a French PWR, it appears that controlled releases would cause an 'economical' accident with limited radiological consequences when compared to other costs; in contrast, massive releases would trigger a major crisis with strong radiological consequences. The two types of crises would confront managers with different types of challenges. (authors)

  14. Realistic assessment of the radiological impact due to radionuclide releases to the terrestrial environment

    International Nuclear Information System (INIS)

    Proehl, G.

    2007-01-01

    Radioecological models are inherently associated with uncertainties, since ecological parameters are subject to a more or less pronounced variability; furthermore, the knowledge of the exposure conditions is - even in the best case - incomplete. To keep models simple and widely applicable and to avoid at the same time underestimations, parameters are selected with a conservative bias. However, conservative results are not appropriate for decision making and optimisation. To discuss the prevention of overly conservative models, in this paper, some selected processes are analysed that are involved in the transfer of radionuclides in the environment as e.g. interception of radionuclides deposited during precipitation by vegetation, systemic transport of radionuclides, migration of radionuclides in soil and speciation in soil. These processes are characterized, and it is discussed which factors should be integrated in modelling to achieve more realistic results. (author)

  15. Modeling of release of radionuclides from an engineered disposal facility for shallow-land disposal of low-level radioactive wastes

    International Nuclear Information System (INIS)

    Matsuzuru, H.; Suzuki, A.

    1989-01-01

    The computer code, ENBAR-1, for the simulation of radionuclide releases from an engineered disposal facility has been developed to evaluate the source term for subsequent migration of radionuclides in and through a natural barrier. The system considered here is that a waste package (waste form and container) is placed, together with backfill materials, into a concrete pit as a disposal unit for shallow-land disposal of low-level radioactive wastes. The code developed includes the following modules: water penetration into a concrete pit, corrosion of a drum as a container, leaching of radionuclides from a waste form, migration of radionuclides in backfill materials, release of radionuclides from the pit. The code has the advantage of its simplicity of operation and presentation while still allowing comprehensive evaluation of each element of an engineered disposal facility to be treated. The performance and source term of the facility might be readily estimated with a few key parameters to define the problem

  16. Box model of radionuclide dispersion and radiation risk estimation for population in case of radioactivity release from nuclear submarine number-sign 601 dumped in the Kara Sea

    International Nuclear Information System (INIS)

    Yefimov, E.I.; Pankratov, D.V.; Ignatiev, S.V.

    1997-01-01

    When ships with nuclear reactors or nuclear materials aboard suffer shipwreck or in the case of burial or dumping of radioactive wastes, atmospheric fallout, etc., radionuclides may be released and spread in the sea, contaminating the sea water and the sea bottom. When a nuclear submarine (NS) is dumped this spread of activity may occur due to gradual core destruction by corrosion over many years. The objective of this paper is to develop a mathematical model of radionuclide dispersion and to assess the population dose and radiation risk for radionuclide release from the NS No. 601, with Pb-Bi coolant that was dumped in the Kara Sea

  17. ACCI38 XL 2: a useful tool for dose assessment in case of accidental atmospheric releases of radionuclides

    International Nuclear Information System (INIS)

    Thomassin, A.; Merle-Szeremeta, A.

    2002-01-01

    In the scope of its assignments in the field of nuclear risks, the French Institute for Radiation protection and Nuclear Safety (IRSN) develops tools to assess the impact of nuclear facilities on their environment and surrounding populations. The code ACCI38 XL 2 is a tool dedicated to the assessment of integrated concentrations in the environment and of dosimetric consequences on man, in case of accidental atmospheric releases of radionuclides (up to 170 radionuclides). This code is widely used by IRSN for studies on accidents, mainly for the analysis of regulatory documents from nuclear operators. The aim of this communication is to present the main features of the model used in the code ACCI38 XL 2, and to give details about the code. After a general presentation of the model, a detailed description of atmospheric dispersion, transfer in the environment and radiological impact is given. Then, some information on parameters and limitations of the model and the code are presented

  18. The measurement of released radionuclides during TIG-Welding and Grinding

    International Nuclear Information System (INIS)

    Reichelt, A.; Lehmann, K.-H.; Reineking, A.; Eder, E.

    2000-01-01

    The radiological relevance of the TIG welding using thoriated tungsten electrodes has recently been proved by means of different studies. As a result of this the TUEV Sueddeutschland and the University of Goettingen have carried out special investigations concerning the release of radionuclides during TIG welding. The main emphasis of these investigations were the representativity of various sampling techniques, the influence of various parameters during welding as well as the determination of activity size distributions related to the aerodynamic diameter of the inhaled aerosols. The properties of the tungsten rods are improved through the addition of radioactive thorium. We investigated the radiation exposure by handling with thoriated tungsten welding rods. We investigated the different exposure pathways and determined the specific activity in dependence to the different types of welding rods. By carrying out surveys with the users, we determined the exposure pathways for the individual exposed persons: TIG - hand-welders', TIG 'machine-welders', labourers, other persons. We measured the activity concentration of the breathing air while welding, at grinding the electrodes and by staying in the rooms where usually it's welded. The size distribution of the aerosol-attached activity was determined with several kinds of impactors. The main emphasis was the comparison of the different sampling systems at the measuring of the activity concentration of the breathing air. Selective sampling by impactors: · Berner-impactor, stationary · Sierra-impactor, stationary · Anderson-Imcaktor, stationary · Marple-impactor, personal sampler Aerosol sampling by air samplers · 5 personal air sampler · 2 stationary sampler, ring face · 2 stationary sampler, open face Rn-220-Measurements · Thoron-monitor Determination of activities on measuring filters · alpha spectrometry · low-level-gamma-spectrometry. For the various exposed persons, at the extern irradiation with gamma

  19. The measurement of released radionuclides during TIG-Welding and Grinding

    Energy Technology Data Exchange (ETDEWEB)

    Reichelt, A.; Lehmann, K.-H. [Technical Inspection Agency of Southern Germany (TUEV Sueddeutschland), Subdepartment Environmental Radioactivity, Munich (Germany); Reineking, A. [Isotope Laboratory for Biological and Medical Research, Georg-August-University of Goettingen, Goettingen (Germany); Eder, E. [Government of Bavaria, State Ministry for State Development and Environmental Affairs, Munich (Germany)

    2000-05-01

    The radiological relevance of the TIG welding using thoriated tungsten electrodes has recently been proved by means of different studies. As a result of this the TUEV Sueddeutschland and the University of Goettingen have carried out special investigations concerning the release of radionuclides during TIG welding. The main emphasis of these investigations were the representativity of various sampling techniques, the influence of various parameters during welding as well as the determination of activity size distributions related to the aerodynamic diameter of the inhaled aerosols. The properties of the tungsten rods are improved through the addition of radioactive thorium. We investigated the radiation exposure by handling with thoriated tungsten welding rods. We investigated the different exposure pathways and determined the specific activity in dependence to the different types of welding rods. By carrying out surveys with the users, we determined the exposure pathways for the individual exposed persons: TIG - hand-welders', TIG 'machine-welders', labourers, other persons. We measured the activity concentration of the breathing air while welding, at grinding the electrodes and by staying in the rooms where usually it's welded. The size distribution of the aerosol-attached activity was determined with several kinds of impactors. The main emphasis was the comparison of the different sampling systems at the measuring of the activity concentration of the breathing air. Selective sampling by impactors: {center_dot} Berner-impactor, stationary {center_dot} Sierra-impactor, stationary {center_dot} Anderson-Imcaktor, stationary {center_dot} Marple-impactor, personal sampler Aerosol sampling by air samplers {center_dot} 5 personal air sampler {center_dot} 2 stationary sampler, ring face {center_dot} 2 stationary sampler, open face Rn-220-Measurements {center_dot} Thoron-monitor Determination of activitys on measuring filters {center_dot} alpha

  20. Transfer into the biosphere of radionuclides released from deep storage of radioactive wastes. Bibliographical study

    International Nuclear Information System (INIS)

    Guedon, V.; Siclet, F.

    1995-03-01

    Most countries with civilian nuclear programs today are encountering difficulty in implementing a nuclear waste management policy that is both technically safe in the long term and accepted by the public. To meet both criteria, the solution most generally envisaged is deep storage either of untreated spent nuclear fuel or of highly radioactive wastes resulting from reprocessing. In order to predict the potential impact of such storage on man, one needs to understand the path followed by radionuclides in the geosphere, and later in the biosphere. Given the time scales involved and the critical nature of the elements concerned, it is indispensable to turn to mathematical modeling of the phenomena. This, however, does not preclude the essential need for in-depth knowledge of the phenomena and of the physico-chemical characteristics of radionuclides. This report presents what is hoped to be a complete inventory of the radionuclides contained in ''high level'' wastes (categories B AND C). The elements concerned in studies on deep storage are essentially long-life radionuclides (both actinides and certain fission and activation products). Their physico-chemical characteristics and their behavior in various ecological compartments are examined. Bibliographical data bearing on: solubility (in an oxidizing, reducing medium), distribution factors (water/rock-sediment-soil), concentration and transfer factors (in aquatic and terrestrial mediums), dose conversion factors (in the case of internal and external irradiation), principal paths of exposure for each radionuclide studied, are presented in this report. Initial results from international projects to model what happens to radionuclides in the biosphere are also presented. In general, they are optimistic as to the future, but nonetheless point to a need to improve the conceptual base of the models, to ensure that all major phenomena and processes are taken into consideration and to examine any possible amplification

  1. The influence of season of the year on the predicted agricultural consequences of accidental releases of radionuclides to atmosphere

    International Nuclear Information System (INIS)

    Simmonds, J.R.

    1985-02-01

    In Europe, because of the seasonal nature of agricultural practices, the consequences for agriculture of an accidental release of radioactive materials to atmosphere are likely to vary depending upon the time of year when the release occurs. The quantification of this variation is complicated by the need to take into account the introduction of countermeasures to restrict the radiation exposure from ingestion of contaminated foods, and by the presence in accidental releases of radionuclides which persist over several seasons. In this study, the effect on agricultural consequences of accidental releases occurring at different times of the year is examined. The consequences are expressed in terms of the amount of produce affected by restrictions on food supplies and the collective radiation dose from ingestion of food. The investigation has been carried out for three hypothetical releases representing a range of releases postulated for pressurised water reactors (PWRs). The effect of season of the year was determined for accidental releases occurring both in a single, defined set of meteorological conditions and for a range of possible meteorological conditions. For the main part of the study, consideration was limited to agricultural production in the UK only, but the effect of extending the analysis beyond the UK boundary was also considered. The results of the study show that considerable variation can occur in agricultural consequences following an accidental release at different times of the year. For the larger releases considered, this variation is reduced due to the effect of the introduction of countermeasures, particularly when consideration is limited to the UK only. Seasonal variation tends to be greater for the results of a deterministic analysis, which uses a single set of constant meteorological conditions, than for the results of a full probabilistic assessment. From the results presented here it is also seen that for many applications of

  2. On release of radionuclides from a near-surface radioactive waste repository to the environment

    Directory of Open Access Journals (Sweden)

    Gudelis Arūnas

    2015-09-01

    Full Text Available A closed near-surface radioactive waste repository is the source of various radionuclides causing the human exposure. Recent investigations confirm an effectiveness of the engineering barriers installed in 2006 to prevent the penetration of radionuclides to the environment. The tritium activity concentration in groundwater decreased from tens of kBq/l to below hundreds of Bq/l. The monitoring and groundwater level data suggest the leaching of tritium from previously contaminated layers of unsaturated zone by rising groundwater while 210Pb may disperse as a decay product of 226Ra daughters.

  3. The role of near-shore industrial waste releases in the dispersion of radionuclides in the NE Irish Sea

    International Nuclear Information System (INIS)

    Hamilton, E.I.

    1999-01-01

    Over the past 27 years, through the use of autoradiographic methods combined with field observations and laboratory studies, I have concluded that the behaviour and distribution of the α-active actinide radionuclides in the estuarine and marine sediments of the NE Irish Sea are significantly influenced by the releases of other non-radioactive industrial wastes. Since the 1700s, the various industrial activities in the Cumbrian coastal region have included: haematite mining, diverse non-ferric metal extraction industries, coal mining and a large number of blast furnaces for the manufacture of iron. More recently (1954-92), the Albright and Wilson phosphoric acid factory at Whitehaven, Cumbria, has discharged large quantities of phosphogypsum slurries into the NE Irish Sea. Iron wastes and slag products, together with phosphogypsum and its associated by-products containing the rare earth elements, are extremely reactive towards the actinides. These wastes are now slowly being removed from the region by natural processes following the rapid decline of heavy industry in the area. These wastes have been present since BNFL first started to discharge radionuclides into the NE Irish Sea and have not, so far, been considered in any models for the dispersion of radionuclides in the region. It is shown that sediments of the NE Irish Sea and local estuaries contain a significant part of the actinide content as coatings on two iron minerals, magnetite and haematite; there is also a significant diffuse distribution associated with hydrated iron oxides attached to quartz grains. However, not all magnetite and haematite grains from a given site show α-activity. Relative to the intensity of the α-activity of the constituent minerals in sediments, the two iron minerals can be regarded as hot particles and are associated with a further set of far more intense hot particles that either may be totally derived from BNFL Sellafield or may also include a contribution from the Albright

  4. Radionuclide trap

    International Nuclear Information System (INIS)

    McGuire, J.C.

    1978-01-01

    The deposition of radionuclides manganese-54, cobalt-58 and cobalt-60 from liquid sodium coolant is controlled by providing surfaces of nickel or high nickel alloys to extract the radionuclides from the liquid sodium, and by providing surfaces of tungsten, molybdenum or tantalum to prevent or retard radionuclide deposition

  5. Local control of striatal dopamine release

    Directory of Open Access Journals (Sweden)

    Roger eCachope

    2014-05-01

    Full Text Available The mesolimbic and nigrostriatal dopamine (DA systems play a key role in the physiology of reward seeking, motivation and motor control. Importantly, they are also involved in the pathophysiology of Parkinson’s and Huntington’s disease, schizophrenia and addiction. Control of DA release in the striatum is tightly linked to firing of DA neurons in the ventral tegmental area (VTA and the substantia nigra (SN. However, local influences in the striatum affect release by exerting their action directly on axon terminals. For example, endogenous glutamatergic and cholinergic activity is sufficient to trigger striatal DA release independently of cell body firing. Recent developments involving genetic manipulation, pharmacological selectivity or selective stimulation have allowed for better characterization of these phenomena. Such termino-terminal forms of control of DA release transform considerably our understanding of the mesolimbic and nigrostriatal systems, and have strong implications as potential mechanisms to modify impaired control of DA release in the diseased brain. Here, we review these and related mechanisms and their implications in the physiology of ascending DA systems.

  6. Modelling the transport of radionuclides released in the Ilha Grande bay (Brazil) after a Large Break Loca ion the primary system of a PWR

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Andre Silva de; Simoes Filho, Francisco Fernando Lamego; Soares, Abner Duarte; Lapa, Celso Marcelo Franklin, E-mail: flamego@ien.gov.b, E-mail: asoares@cnen.gov.b, E-mail: lapa@ien.gov.b [Instituto de Engenharia Nuclear (LIMA/IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2011-07-01

    It was postulated, in the cooling system of the core, a LOCA, where 431 m{sup 3} of soda almost instantaneously was lost. This inventory contained 1.87x10{sup 10} Bq/m{sup 3} of tritium, 2.22x10{sup 7} Bq/m{sup 3} of cobalt,3.48x10{sup 8} Bq/m{sup 3} of cesium and 3.44x10{sup 10} Bq/m{sup 3} of iodine and was released in liquid form near the Itaorna cove, Angra dos Reis - RJ. Applying the model in the proposed scenario (Angra 1 and 2 in operation and Angra 3 progressively reducing the capture and discharge after the accident), the simulated dilution of the specific activity of radionuclide spots, reached values much lower than report levels for seawater (1,1x10{sup 6} Bq/m{sup 3}, 1,11x10{sup 4} Bq/m{sup 3} and 1,85x10{sup 3} Bq/m{sup 3}) after 22 hours, respectively for {sup 3}H, {sup 60}Co, {sup 131}I and {sup 137}Cs. From the standpoint of public exposure to radionuclide dispersion, the results of activity concentration obtained by the model suggest that the observed radiological impact is negligible. Based on these findings, we conclude that there would be no radiological impact related to a further release of controlled effluent discharges into Itaorna cove. (author)

  7. Modelling the transport of radionuclides released in the Ilha Grande bay (Brazil) after a Large Break Loca ion the primary system of a PWR

    International Nuclear Information System (INIS)

    Aguiar, Andre Silva de; Simoes Filho, Francisco Fernando Lamego; Soares, Abner Duarte; Lapa, Celso Marcelo Franklin

    2011-01-01

    It was postulated, in the cooling system of the core, a LOCA, where 431 m 3 of soda almost instantaneously was lost. This inventory contained 1.87x10 10 Bq/m 3 of tritium, 2.22x10 7 Bq/m 3 of cobalt,3.48x10 8 Bq/m 3 of cesium and 3.44x10 10 Bq/m 3 of iodine and was released in liquid form near the Itaorna cove, Angra dos Reis - RJ. Applying the model in the proposed scenario (Angra 1 and 2 in operation and Angra 3 progressively reducing the capture and discharge after the accident), the simulated dilution of the specific activity of radionuclide spots, reached values much lower than report levels for seawater (1,1x10 6 Bq/m 3 , 1,11x10 4 Bq/m 3 and 1,85x10 3 Bq/m 3 ) after 22 hours, respectively for 3 H, 60 Co, 131 I and 137 Cs. From the standpoint of public exposure to radionuclide dispersion, the results of activity concentration obtained by the model suggest that the observed radiological impact is negligible. Based on these findings, we conclude that there would be no radiological impact related to a further release of controlled effluent discharges into Itaorna cove. (author)

  8. Safety case for the disposal of spent nuclear fuel at Olkiluoto. Assessment of radionuclide release scenarios for the repository system 2012

    International Nuclear Information System (INIS)

    2012-12-01

    Assessment of Radionuclide Release Scenarios sits within Posiva Oy's Safety Case 'TURVA-2012' report portfolio and has the objective of presenting an assessment of the repository system scenarios leading to radionuclide releases that have been identified in Formulation of Radionuclide Release Scenarios. A base scenario, variant scenarios and disturbance scenarios are considered. For each scenario, a range of calculation cases, also identified in Formulation of Radionuclide Release Scenarios, has been analysed, complemented by Monte Carlo simulations, a probabilistic sensitivity analysis and other supporting calculations. The calculation cases and analyses take into account major uncertainties in the initial state of the barriers and possible paths for the evolution of the repository system identified in Performance Assessment. Quality control and assurance measures have been adopted to ensure transparency and traceability of the calculations performed and hence to promote confidence in the analysis of the calculation cases. The calculation cases each consider a single, failed canister, where three possible modes of failure are addressed: (1) the presence of an initial penetrating defect in the copper overpack of the canister, (2) corrosion of the copper overpack, which occurs most rapidly in scenarios in which buffer density is reduced, e.g. by erosion, (3) shear movement on a fracture intersecting a deposition hole. The likelihood and consequences of multiple canister failure occurring during the assessment time frame are also considered. In particular, the analyses consider: The likelihood and consequences of there being multiple canisters with initial penetrating defects; The consequences if canister failure due to corrosion following buffer erosion were to occur; and The low annual probability of there being an earthquake large enough to give rise to canister failure due to rock shear movements and the potential consequences of such an earthquake, taking into

  9. Safety case for the disposal of spent nuclear fuel at Olkiluoto. Assessment of radionuclide release scenarios for the repository system 2012

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-12-15

    Assessment of Radionuclide Release Scenarios sits within Posiva Oy's Safety Case 'TURVA-2012' report portfolio and has the objective of presenting an assessment of the repository system scenarios leading to radionuclide releases that have been identified in Formulation of Radionuclide Release Scenarios. A base scenario, variant scenarios and disturbance scenarios are considered. For each scenario, a range of calculation cases, also identified in Formulation of Radionuclide Release Scenarios, has been analysed, complemented by Monte Carlo simulations, a probabilistic sensitivity analysis and other supporting calculations. The calculation cases and analyses take into account major uncertainties in the initial state of the barriers and possible paths for the evolution of the repository system identified in Performance Assessment. Quality control and assurance measures have been adopted to ensure transparency and traceability of the calculations performed and hence to promote confidence in the analysis of the calculation cases. The calculation cases each consider a single, failed canister, where three possible modes of failure are addressed: (1) the presence of an initial penetrating defect in the copper overpack of the canister, (2) corrosion of the copper overpack, which occurs most rapidly in scenarios in which buffer density is reduced, e.g. by erosion, (3) shear movement on a fracture intersecting a deposition hole. The likelihood and consequences of multiple canister failure occurring during the assessment time frame are also considered. In particular, the analyses consider: The likelihood and consequences of there being multiple canisters with initial penetrating defects; The consequences if canister failure due to corrosion following buffer erosion were to occur; and The low annual probability of there being an earthquake large enough to give rise to canister failure due to rock shear movements and the potential consequences of such an earthquake

  10. Controlled release studies of calcium alginate hydrogels

    International Nuclear Information System (INIS)

    Rendevski, S.; Andonovski, A.; Mahmudi, N.

    2012-01-01

    Controlled release of substances in many cases may be achieved from calcium alginate hydrogels. In this research, the time dependence of the mass of released model substance bovine serum albumin (BSA) from calcium alginate spherical hydrogels of three different types (G/M ratio) have been investigated. The hydrogels were prepared with the drop-wise method of sodium alginate aqueous solutions with concentration of 0.02 g/cm 3 with 0.01 g/cm 3 BSA and a gelling water bath of chitosan in 0.2 M CH 3 COOH/0.4 M CH 3 COONa with added 0.2 M CaCl 2 .The hydrogel structures were characterized by dynamic light scattering and scanning electron microscopy. The controlled release studies were conducted by UV-Vis spectrophotometry of the released medium with p H=7 at 37 °C. The results showed that the model of osmotic pumping is the dominant mechanism of the release. Also, large dependences of the release profile on the homogeneity of the hydrogels were found. (Author)

  11. Electrosprayed nanoparticle delivery system for controlled release

    Energy Technology Data Exchange (ETDEWEB)

    Eltayeb, Megdi, E-mail: megdi.eltayeb@sustech.edu [Department of Biomedical Engineering, Sudan University of Science and Technology, PO Box 407, Khartoum (Sudan); Stride, Eleanor, E-mail: eleanor.stride@eng.ox.ac.uk [Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Old Road Campus Research Building, Headington OX3 7DQ (United Kingdom); Edirisinghe, Mohan, E-mail: m.edirisinghe@ucl.ac.uk [Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE (United Kingdom); Harker, Anthony, E-mail: a.harker@ucl.ac.uk [London Centre for Nanotechnology, Gordon Street, London WC1H 0AH (United Kingdom); Department of Physics & Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)

    2016-09-01

    This study utilises an electrohydrodynamic technique to prepare core-shell lipid nanoparticles with a tunable size and high active ingredient loading capacity, encapsulation efficiency and controlled release. Using stearic acid and ethylvanillin as model shell and active ingredients respectively, we identify the processing conditions and ratios of lipid:ethylvanillin required to form nanoparticles. Nanoparticles with a mean size ranging from 60 to 70 nm at the rate of 1.37 × 10{sup 9} nanoparticles per minute were prepared with different lipid:ethylvanillin ratios. The polydispersity index was ≈ 21% and the encapsulation efficiency ≈ 70%. It was found that the rate of ethylvanillin release was a function of the nanoparticle size, and lipid:ethylvanillin ratio. The internal structure of the lipid nanoparticles was studied by transmission electron microscopy which confirmed that the ethylvanillin was encapsulated within a stearic acid shell. Fourier transform infrared spectroscopy analysis indicated that the ethylvanillin had not been affected. Extensive analysis of the release of ethylvanillin was performed using several existing models and a new diffusive release model incorporating a tanh function. The results were consistent with a core-shell structure. - Highlights: • Electrohydrodynamic spraying is used to produce lipid-coated nanoparticles. • A new model is proposed for the release rates of active components from nanoparticles. • The technique has potential applications in food science and medicine. • Electrohydrodynamic processing controlled release lipid nanoparticles.

  12. Massive radiological releases profoundly differ from controlled releases

    International Nuclear Information System (INIS)

    Pascucci-Cahen, Ludivine; Patrick, Momal

    2013-01-01

    In this article, the authors report identification and assessment of different types of costs associated with nuclear accidents. They first outline that these cost assessments must be as exhaustive or comprehensive as possible. While referring to past accidents, they define the different categories of costs: on-site costs (decontamination and dismantling, electricity not produced on the site), off-site costs (health costs, psychological costs, farming losses), image-related costs (impact on food and farm product exports, decrease of other exports), costs related to energy production, costs related to contaminated areas (refugees, lands). They give an assessment of a severe nuclear accident (i.e. an accident with important but controlled radiological releases) in France and outline that it would be a national catastrophe which could be however managed. They discuss the possible variations of the estimated costs. Then, they show that a major accident (i.e. an accident with massive radiological releases) in France would be an unmanageable European catastrophe because of the radiological consequences, of high economic costs, and of huge losses

  13. Arrival of radionuclides released by the Fukushima accident to Tenerife (Canary Islands)

    International Nuclear Information System (INIS)

    López-Pérez, M.; Ramos-López, R.; Perestelo, Nayra R.; Duarte-Rodriguez, X.; Bustos, J.J.; Alonso-Pérez, S.; Cuevas, E.; Hernández-Armas, J.

    2013-01-01

    Two weeks after the accident at the Fukushima-Daichi nuclear power plant, 131I, 137Cs and 134Cs activities were measured in two different stations located in Tenerife (Canary Islands), situated at 300 (FIMERALL) and 2400 (IZAÑA) m.a.s.l, respectively. Peak measured activity concentrations were: 1.851 mBq/m3 (131I); 0.408 mBq/m3 (137Cs) and 0.382 mBq/m3 (134Cs). The activities measured at the FIMERALL station were always higher than at IZAÑA station, suggesting that the radioactive plume arrived to the island associated with low altitude air masses. Simulations of potential dispersion of the radioactive cloud (137Cs) after the nuclear accident in reactor Fukushima I show that radioactive pollution reached remote regions such as the Canary Islands in the Eastern subtropical North Atlantic. The corresponding effective dose to the local population was 1.17 nSv, a value less than one millionth of the annual limit for the general public. Therefore, there was no risk to public health. - Highlights: ► Arrival of radionuclides to Tenerife following the accident of Fukushima. ► The atmospheric concentration of radionuclides was always higher at low altitude. ► After reaching the peak concentration a sharp decrease of radionuclides was observed. ► Air mass forward trajectory analysis confirms the potential arrival of radionuclides to Tenerife.

  14. The variability of the potential radiation exposure to man arising from radionuclides released to the ground water

    International Nuclear Information System (INIS)

    Proehl, G.; Mueller, H.

    1994-12-01

    The variability of the potential radiation exposure of the population is estimated if radionuclides (Np-237, Tc-99, I-129, Cs-135, Ra-226, U-238) are released to the ground water which is used by man as drinking water for humans and animals, for irrigation of food and feed crops, and for the production of fish in freshwater bodies. Annual effective dose equivalents are calculated assuming a normalized activity concentration in the water of 1 Bq/l for each radionuclide considered. An important aim is the estimation of the uncertainty of the exposure due to the uncertainty and the variability of the input parameters. The estimated frequency distributions of the input parameters were used as a model input and processed with Latin Hypercube Sampling and a Monte-Carlo technique. This estimation is based on an exposure scenario which reflects the present conditions. The critical group for the exposure due to the use of contaminated ground water are for most radionuclides the children of 1 year, although the activity intake of children is much lower than for adults. However the ingestion dose factors for infants are higher; in many cases the differences are higher than a factor of 5. (orig./HP)

  15. Control of semivolatile radionuclides in gaseous effluents at nuclear facilities

    International Nuclear Information System (INIS)

    1982-01-01

    An up-to-date review is presented of the subject, combining the results of laboratory studies on control of the most important semivolatile radionuclides in gaseous effluents at nuclear facilities and the results of operating experience in that area. Ruthenium is the most significant semivolatile contaminant in gaseous effluents at nuclear facilities. Volatilization of ruthenium can be reduced by various means, in particular by adding reductants. Volatilized ruthenium can be retained by adsorbents such as silica gel and ferric-oxide-based materials. Decontamination factors in the order of 10 3 have been obtained with these adsorbents under optimum conditions. Volatilized ruthenium can also be removed by other equipment such as condensers and scrubbers. Experience with high-level liquid waste solidification plants has shown that, in general, ruthenium volatilization is in the order of 10% or more unless special treatment is undertaken. There is little experience with ruthenium adsorbers in plants. Silica gel seems to have performed best, with ruthenium decontamination factors of about 10 2 to 10 3 . However, feed-to-stack ruthenium decontamination factors of 10 9 or more have been obtained even without ruthenium adsorbers. Other semivolatiles are relatively insignificant under normal conditions because of a low level of volatilization potential or mass or activity in the inventory. Moreover, owing to particulate formation, they can be easily removed without specific equipment

  16. Production and quality control of 65Zn radionuclide

    International Nuclear Information System (INIS)

    Rowshanfarzad, P.; Jalilian, R.; Sabet, M.

    2005-01-01

    Zinc-65 was produced in the Nuclear Research Center for Agriculture and Medicine (NRCAM) by the bombardment of natural copper targets with 30 MeV protons via the 65 Cu(p,n) 65 Zn nuclear reaction. Natural copper was used instead of enriched 65 Cu because of the quick decay of undesired radioisotopes. It was also more desirable for cost effectiveness. Cross-section calculations were performed by ALICE nuclear code and the results were compared with the experimental data given in the literature, which showed good agreement. A 160 μm copper layer target was bombarded with a 150 μA current of 30 MeV protons for 20 min, which resulted in 170 MBq activity of 65 Zn product. The yield was 3.4 MBq/μAh. The concentration of the product was 6.8 MBq/ml. Radiochemical separation was carried out by anion exchange chromatography with the yield of about 98%. Quality control of the final product showed a radionuclide purity of more than 98% and no traces of possible impurities (copper) were detected by a colorimetric method with a 1 ppm detection limit using dithizone as the reagent. The materials used for targetry and chemical separation were quite cost-effective. (author)

  17. Radionuclide dispersion and hydrodynamics of Ilha Grande Bay (Angra dos Reis, RJ) simulated from hypothetical accidental releases of liquid wastes

    International Nuclear Information System (INIS)

    Simoes Filho, Fernando Lamego; Lapa, Celso Marcelo Franklin; Aguiar, Andre Silva; Soares, Abner Duarte

    2011-01-01

    This study has the aim to assess the impact of accidental release of radionuclides postulate from a nuclear power reactor through environmental modeling of aquatic resources. In order to do that it was used computational models of hydrodynamic circulation and transport for the simulation of tritium dispersion caused by an accidental release in Ilha Grande Bay from the site of the future third plant in two circulation scenarios. The main difference between the scenarios is based on the enhancement of dilution of the highest concentrations in the last one. This dilution enhancement resulting in decreasing concentrations was observed only during the first two weeks, when they ranged from 1 x 10 9 to 5 x 10 5 Bq/m³ close to the Itaorna beach spreading just to Sandri Island. After 180 days, the plume could not be detected anymore in the bay, because their activities would be lower than the minimum detectable value (< 11 kBq/m³). (author)

  18. Radioanalytical procedures used to study the release of radionuclides from spent nuclear fuel and the diffusion into bentonite clay

    International Nuclear Information System (INIS)

    Ramebaeck, H.; Albinsson, Yngve; Skaalberg, M.; Eklund, U.B.

    1999-12-01

    This report presents radio-analytical procedures for the assay of 90 Sr, 99 Tc, 237 Np, 239 Pu, 241 Am and 244 Cm. These analytical procedures were used in a project studying the release and diffusion of radionuclides from spent nuclear fuel into bentonite clay. The main task was to use methods giving a high specificity in the detection combined with a low detection limit. A high specificity will eliminate errors caused by interferences, yielding errors in the analysis. A low detection limit was necessary since the release was often very low. Solvent extraction was used in order to remove interferences. The detection methods, radiometric or mass spectrometric, were chosen to give the lowest detection limit

  19. Stimuli responsive nanomaterials for controlled release applications

    KAUST Repository

    Li, Song; Li, Wengang; Khashab, Niveen M.

    2012-01-01

    applications. Stimuli-responsive nanomaterials guarantee the controlled release of cargo to a given location, at a specific time, and with an accurate amount. In this review, we have combined the major stimuli that are currently used to achieve the ultimate

  20. Bioadhesive Controlled Release Clotrimazole Vaginal Tablets | Bhat ...

    African Journals Online (AJOL)

    Conclusion: This study indicates the possible use of suitable mixtures of natural and semi-synthetic cellulosic polymers for the preparation of clotrimazole mucoadhesive tablets for application as a vaginal controlled delivery system. Keywords: Clotrimazole, Swelling, Cellulosic polymers, Guar gum, Bioadhesion, Release ...

  1. Use of depleted uranium silicate glass to minimize release of radionuclides from spent nuclear fuel waste packages

    International Nuclear Information System (INIS)

    Forsberg, C.W.

    1996-01-01

    A Depleted Uranium Silicate Container Backfill System (DUSCOBS) is proposed that would use small, isotopically-depleted uranium silicate glass beads as a backfill material inside repository waste packages containing spent nuclear fuel (SNF). The uranium silicate glass beads would fill the void space inside the package including the coolant channels inside SNF assemblies. Based on preliminary analysis, the following benefits have been identified. DUSCOBS improves repository waste package performance by three mechanisms. First, it reduces the radionuclide releases from SNF when water enters the waste package by creating a local uranium silicate saturated groundwater environment that suppresses (a) the dissolution and/or transformation of uranium dioxide fuel pellets and, hence, (b) the release of radionuclides incorporated into the SNF pellets. Second, the potential for long-term nuclear criticality is reduced by isotopic exchange of enriched uranium in SNF with the depleted uranium (DU) in the glass. Third, the backfill reduces radiation interactions between SNF and the local environment (package and local geology) and thus reduces generation of hydrogen, acids, and other chemicals that degrade the waste package system. Finally, DUSCOBS provides a potential method to dispose of significant quantities of excess DU from uranium enrichment plants at potential economic savings. DUSCOBS is a new concept. Consequently, the concept has not been optimized or demonstrated in laboratory experiments

  2. Radionuclides and isotopes release of spent fuel matrix. Conceptual and mathematical models of wastes behaviour; Liberacion de los radionucleidos e isotopos estables contenidos en la matriz del combustible. Modelo conceptual y modelo matematico del comportamiento del residuo

    Energy Technology Data Exchange (ETDEWEB)

    Cera, E.; Merino, J.; Bruno, J.

    2000-07-01

    We have developed a conceptual and numerical model to calculate release of selected radionuclides from spent fuel under repository condition. This has been done in the framework of the Enresa 2000 performance assessment exercise. The model has been developed based on kinetic mass balance equations in order to study the evolution of the spent fuel water interface as a function of time. Several processes have been kinetically modelled: congruent dissolution, radioactive decay, ingrowth and water turnover in the gap. The precipitation/redissolution of secondary solid phases has been taken into account from a thermodynamic point of view. Both approaches have been coupled and the resulting equations solved for a number of radionuclides in both, a conservative and realistic approach. The results show three distinct groups of radionuclides based on their release behaviour: a first group is composed of radioisotopes of highly insoluble elements (e. g., Pu, Am, Pd) whose concentration in the gap is mainly controlled by their solubility and therefore their evolution is identical in both cases. Secondly, a set of radionuclides from soluble elements under these conditions (e. g., I, Cs, Ra) show concentrations kinetically controlled, decreasing with time following the congruent dissolution trend. Their release concentrations are one order of magnitude larger in the conservative case than in the realistic case. Finally, a third group has been identified (e. g., Se, Th, Cm) where a mixed behaviour takes place: initially their solubility limiting phases control their concentration in the gap but the situation reverts to a kinetic control as the chemical conditions change and the secondary precipitates become totally dissolved. The fluxes of the different radionuclides are also given as an assessment of the source term in the performance assessment. (Author)

  3. Radiation monitoring for radionuclide release in water system resulted from nuclear power plant operation

    International Nuclear Information System (INIS)

    Vintsukevich, N.V.; Tomilin, Yu.A.

    1983-01-01

    Pre-operational investigation into environmental radioactivity in the vicinity of Yuzhno-Ukrainskaya NPP with reverse- direct flow cooling scheme of circulating water was conducted. Considering that reservoir-coolant of NPP will be connected constantly with water reservoirs located on the Yuzhnyj Bug river possibilities of radionuclide accumulation in different river components - 5ilt, algae, river water-were investigated. It was established that increase of pH and salt concentration in water of river undercurrent create the conditions for formation of radionuclide sedimentary forms, increase their accumulation in bottom sediments and aqquatic vegetation. The conclusion on the necessity of constant radiation monitoring for relase of liquid coastes of Yuzhno-Ukrainskaya NPP in the Yuzhnyj Bug river is drawn

  4. Release of airborne radionuclides from Olympic Dam operations and exposure assessment for members of the public

    International Nuclear Information System (INIS)

    Harris, F.F.; Chandler, W.P.

    1992-01-01

    Olympic Dam Operations, a copper, uranium, silver and gold producing project, is situated in a semi-arid area 550 km north of Adelaide. Airborne dispersal is the major transport pathway of operation-related radionuclides to members of the public, and as such has become the focus of a major environmental monitoring program. Major emissions consist of radon and its associated daughters and radionuclides in dust that originate from mine, metallurgical plant, ore and mullock stockpiles and the tailings retention system. Dispersion modelling and measured ground level concentrations have been utilised to calculate the effective dose equivalent for three critical groups. All critical groups exposures are less than 0.2 mSv by the most conservative calculation and are well below the legislative limit of 1 mSv applicable to members of the public. 12 refs., 5 gabs., 12 figs

  5. TERRA: a computer code for simulating the transport of environmentally released radionuclides through agriculture

    International Nuclear Information System (INIS)

    Baes, C.F. III; Sharp, R.D.; Sjoreen, A.L.; Hermann, O.W.

    1984-11-01

    TERRA is a computer code which calculates concentrations of radionuclides and ingrowing daughters in surface and root-zone soil, produce and feed, beef, and milk from a given deposition rate at any location in the conterminous United States. The code is fully integrated with seven other computer codes which together comprise a Computerized Radiological Risk Investigation System, CRRIS. Output from either the long range (> 100 km) atmospheric dispersion code RETADD-II or the short range (<80 km) atmospheric dispersion code ANEMOS, in the form of radionuclide air concentrations and ground deposition rates by downwind location, serves as input to TERRA. User-defined deposition rates and air concentrations may also be provided as input to TERRA through use of the PRIMUS computer code. The environmental concentrations of radionuclides predicted by TERRA serve as input to the ANDROS computer code which calculates population and individual intakes, exposures, doses, and risks. TERRA incorporates models to calculate uptake from soil and atmospheric deposition on four groups of produce for human consumption and four groups of livestock feeds. During the environmental transport simulation, intermediate calculations of interception fraction for leafy vegetables, produce directly exposed to atmospherically depositing material, pasture, hay, and silage are made based on location-specific estimates of standing crop biomass. Pasture productivity is estimated by a model which considers the number and types of cattle and sheep, pasture area, and annual production of other forages (hay and silage) at a given location. Calculations are made of the fraction of grain imported from outside the assessment area. TERRA output includes the above calculations and estimated radionuclide concentrations in plant produce, milk, and a beef composite by location

  6. TERRA: a computer code for simulating the transport of environmentally released radionuclides through agriculture

    Energy Technology Data Exchange (ETDEWEB)

    Baes, C.F. III; Sharp, R.D.; Sjoreen, A.L.; Hermann, O.W.

    1984-11-01

    TERRA is a computer code which calculates concentrations of radionuclides and ingrowing daughters in surface and root-zone soil, produce and feed, beef, and milk from a given deposition rate at any location in the conterminous United States. The code is fully integrated with seven other computer codes which together comprise a Computerized Radiological Risk Investigation System, CRRIS. Output from either the long range (> 100 km) atmospheric dispersion code RETADD-II or the short range (<80 km) atmospheric dispersion code ANEMOS, in the form of radionuclide air concentrations and ground deposition rates by downwind location, serves as input to TERRA. User-defined deposition rates and air concentrations may also be provided as input to TERRA through use of the PRIMUS computer code. The environmental concentrations of radionuclides predicted by TERRA serve as input to the ANDROS computer code which calculates population and individual intakes, exposures, doses, and risks. TERRA incorporates models to calculate uptake from soil and atmospheric deposition on four groups of produce for human consumption and four groups of livestock feeds. During the environmental transport simulation, intermediate calculations of interception fraction for leafy vegetables, produce directly exposed to atmospherically depositing material, pasture, hay, and silage are made based on location-specific estimates of standing crop biomass. Pasture productivity is estimated by a model which considers the number and types of cattle and sheep, pasture area, and annual production of other forages (hay and silage) at a given location. Calculations are made of the fraction of grain imported from outside the assessment area. TERRA output includes the above calculations and estimated radionuclide concentrations in plant produce, milk, and a beef composite by location.

  7. Radionuclide toxicity

    International Nuclear Information System (INIS)

    Galle, P.

    1982-01-01

    The aim of this symposium was to review the radionuclide toxicity problems. Five topics were discussed: (1) natural and artificial radionuclides (origin, presence or emission in the environment, human irradiation); (2) environmental behaviour of radionuclides and transfer to man; (3) metabolism and toxicity of radionuclides (radioiodine, strontium, rare gas released from nuclear power plants, ruthenium-activation metals, rare earths, tritium, carbon 14, plutonium, americium, curium and einsteinium, neptunium, californium, uranium) cancerogenous effects of radon 222 and of its danghter products; (4) comparison of the hazards of various types of energy; (5) human epidemiology of radionuclide toxicity (bone cancer induction by radium, lung cancer induction by radon daughter products, liver cancer and leukaemia following the use of Thorotrast, thyroid cancer; other site of cancer induction by radionuclides) [fr

  8. The calculating methods of the release of airborne radionuclides to environment during the normal operation of a module high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Liu Yuanzhong

    1993-01-01

    The calculations of the release of radionuclides to environment are the basis of environmental impact assessment during the normal operation of a module high temperature gas-cooled reactor of the Institute of Nuclear Energy Technology, Tsinghua University, China. According to the features of the reactor it is pointed out that only five sources of the airborne radioactive materials released to environment are important. They are: (1) the activation of the air in the reactor cavity; (2) the escape from the primary coolant systems; (3) the release of radioactively contaminated helium from storage tanks; (4) the release of radioactively contaminated helium from the gas evacuation system of fuel load and unload system; (5) the leakage of the vapour from water-steam loop. In accordance with five release sources the calculating methods of radionuclides released to environment are worked out respectively and the respective calculating formulas are derived for the normal operation of the reactor

  9. EPICS application source/release control

    International Nuclear Information System (INIS)

    Zieman, B.; Anderson, J.; Kraimer, M.

    1995-01-01

    This manual describes a set of Application Source/Release Control tools (appSR) that can be used to develop software for EPICS based control systems. The Application Source/Release Control System (appSR) has been unbundled from base EPICS and is now available as an EPICS extension. Due to this unbundling, two new directories must be added to a user's path (see section ''Environment'' on page 3 for more information) and a new command getapp must be issued after the getrel command to get a specific version of appSR (see section ''Creating The Initial Application System Area'' on page 7 for more information). It is now required that GNU make version 3.71 or later be used for makes instead of SUN make. Users should now type gmake instead of make

  10. Quality control of radionuclide calibrators used in nuclear medicine services in the Brazilian northeast region

    International Nuclear Information System (INIS)

    Fragoso, Maria C.F.; Albuquerque, Antonio M.S.; Oliveira, Mercia L.; Lima, Ricardo A.; Lima, Fabiana F.

    2011-01-01

    The radionuclide calibrators are essential instruments in nuclear medicine services in order to activity determination of radiopharmaceuticals which will be administered to the patients. Inappropriate performance of these equipment could provide underestimation or overestimation of the activity, compromising the success of diagnosis or therapeutic procedures. To ensure the satisfactory performance of the radionuclide calibrators, quality control tests are recommended by national and international guides. The aim of this work was evaluate the establishment of the quality control program in the radionuclide calibrators at medicine nuclear services in the Brazilian northeast region, highlighting the tests and their frequencies. (author)

  11. Radionuclides release from re-irradiated fuel under high temperature and pressure conditions. Gamma-ray measurements of VEGA-5 test

    Energy Technology Data Exchange (ETDEWEB)

    Hidaka, Akihide; Kudo, Tamotsu; Nakamura, Takehiko; Kanazawa, Toru; Kiuchi, Toshio; Uetsuka, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    The VEGA (Verification Experiments of radionuclides Gas/Aerosol release) program is being performed at JAERI to clarify mechanisms of radionuclides release from irradiated fuel during severe accidents and to improve source term predictability. The fifth VEGA-5 test was conducted in January 2002 to confirm the reproducibility of decrease in cesium release under elevated pressure that was observed in the VEGA-2 test and to investigate the release behavior of short-life radionuclides. The PWR fuel of 47 GWd/tU after about 8.2 years of cooling was re-irradiated at Nuclear Safety Research Reactor (NSRR) for 8 hours before the heat-up test. After that, the two pellets of 10.9 g without cladding were heated up to about 2,900 K at 1.0 MPa under the inert He condition. The experiment reconfirmed the decrease in cesium release rate under the elevated pressure. The release data on short-life radionuclides such as Ru-103, Ba-140 and Xe-133 that have never been observed in the previous VEGA tests without re-irradiation was obtained using the {gamma} ray measurement. (author)

  12. Release and Movement of Radionuclides in Soils Contaminated with Fallout Materials from an Underground Thermonuclear Detonation

    Science.gov (United States)

    1962-07-06

    Studies The degree of dissolution of the fallout material in H2 0, HCl, DTPA, CDTA, and EDDHA solutions was investigated by the suspension method...days was: EDDHA >DTPA>CDTA>H 2 0. while after 65 days the order of effect was: CDTA> EDDHA >DTPA>H 20. Portions of gamma ray spectra of the 106 day...the same amounts of radionuclides as did H120. The most abundant radio- nuclide was radiotungsten for H120, DTPA, CDTA, and EDDHA supernatant liquids

  13. The challenges posed by radiation and radionuclide releases to the environment.

    Science.gov (United States)

    Wenning, Richard J; Apitz, Sabine E; Backhaus, Thomas; Barnthouse, Lawrence; Batley, Graeme; Brooks, Bryan; Chapman, Peter M; Griffin, Michael; Kapustka, Lawrence; Landis, Wayne; Leung, Kenneth M Y; Linkov, Igor; Seager, Thomas P; Suter, Glenn; Tannenbaum, Lawrence

    2011-07-01

    The recent accident at the Fukushima I nuclear power plant in Japan (also known as Fukushima Daiichi) captured the world's attention and re-invigorated concerns about the safety of nuclear power technology. The Editors of Integrated Environmental Assessment and Management invited experts in the field to describe the primary issues associated with the control and release of radioactive materials to the environment, particularly those that are of importance to the health of the human populations and the ecological systems that populate our planet. This collection of invited short commentaries aims to inform on the safety of nuclear power plants damaged by natural disasters and provide a primer on the potential environmental impacts. The intent of these invited commentaries is not to fuel the excitement and fears about the Fukushima Daiichi incident; rather, it is to collect views and comments from some of the world's experts on the broad science and policy challenges raised by this event, and to provide high-level views on the science issues that surround this situation in order to improve our collective ability to avoid or at least minimize the consequences of future events. Copyright © 2011 SETAC.

  14. Meltable magnetic biocomposites for controlled release

    Energy Technology Data Exchange (ETDEWEB)

    Müller, R., E-mail: robert.mueller@ipht-jena.de [Leibniz Institute of Photonic Technology (IPHT), P.O.B. 100239, Jena, D-07702 Germany (Germany); Zhou, M. [Institute of Organic Chemistry and Macromolecular Chemistry, Friedrich Schiller University of Jena, Humboldtstrasse 10, Jena, D-07743 Germany (Germany); Dellith, A. [Leibniz Institute of Photonic Technology (IPHT), P.O.B. 100239, Jena, D-07702 Germany (Germany); Liebert, T.; Heinze, T. [Institute of Organic Chemistry and Macromolecular Chemistry, Friedrich Schiller University of Jena, Humboldtstrasse 10, Jena, D-07743 Germany (Germany)

    2017-06-01

    New biocompatible composites with adjustable melting point in the range of 30–140 °C, consisting of magnetite nanoparticles embedded into a matrix of meltable dextran fatty acid ester are presented which can be softened under an induced alternating magnetic field (AMF). The chosen thermoplastic magnetic composites have a melting range close to human body temperature and can be easily shaped into disk or coating film under melting. The composite disks were loaded with green fluorescent protein (GFP) as a model protein. Controlled release of the protein was realized with high frequent alternating magnetic field of 20 kA/m at 400 kHz. These results showed that under an AMF the release of GFP from magnetic composite was accelerated compared to the control sample without exposure to AMF. Furthermore a texturing of particles in the polymer matrix by a static magnetic field was investigated. - Highlights: • Thermoplastic biocomposite are prepared from dextran ester and magnetite particles. • The composite can be heated by an AC magnetic field above the melting temperature. • In molten state texturing of particles is possible and improves the heating ability. • The biopolymer could be used as a remote controlled matrix for protein release.

  15. The release of organic material from clay based buffer materials and its potential implications for radionuclide transport

    International Nuclear Information System (INIS)

    Vilks, P.; Stroes-Gascoyne, S.; Goulard, M.; Haveman, S.A.; Bachinski, D.B.

    1998-01-01

    In the Canadian nuclear fuel waste disposal concept used fuel would be placed in corrosion resistant containers which would be surrounded by clay-based buffer and backfill materials in an engineered vault excavated at 500 to 1000 m depth in crystalline rock formations in the Canadian shield. Organic substances could affect radionuclide mobility due to the effects of redox and complexation reactions that increase solubility and alter mobility. The purpose of this study was to determine whether the buffer and backfill materials, proposed for use in a disposal vault, contain organics that could be leached by groundwater in large enough quantities to affect radionuclide mobility within the disposal vault and surrounding geosphere complex. Buffer material, made from a mixture of 50 wt.% Avonlea sodium bentonite and 50 wt.% silica sand, was extracted with deionized water to determine the release of dissolved organic carbon (DOC), humic acid and fulvic acid. The effect of radiation and heat from the used fuel was simulated by treating samples of buffer before leaching to various amounts of heat (60 and 90 C) for periods of 2, 4 and 6 weeks, and to ionizing radiation with doses of 25 kGy and 50 kGy. The results showed that groundwater would leach significant amounts of organics from buffer that complex with radionuclides such as the actinides, potentially affecting their solubility and transport within the disposal vault and possibly the surrounding geosphere. In addition, the leached organics would likely stimulate microbial growth by several orders of magnitude. Heating and radiation affect the amount and nature of leachable organics. (orig.)

  16. Controlled drug release from bifunctionalized mesoporous silica

    Science.gov (United States)

    Xu, Wujun; Gao, Qiang; Xu, Yao; Wu, Dong; Sun, Yuhan; Shen, Wanling; Deng, Feng

    2008-10-01

    Serial of trimethylsilyl-carboxyl bifunctionalized SBA-15 (TMS/COOH/SBA-15) have been studied as carriers for controlled release of drug famotidine (Famo). To load Famo with large capacity, SBA-15 with high content of carboxyl groups was successfully synthesized by one-pot synthesis under the assistance of KCl. The mesostructure of carboxyl functionalized SBA-15 (COOH/SBA-15) could still be kept even though the content of carboxyl groups was up to 57.2%. Increasing carboxyl content could effectively enhance the loading capacity of Famo. Compared with pure SBA-15, into which Famo could be hardly adsorbed, the largest drug loading capacity of COOH/SBA-15 could achieve 396.9 mg/g. The release of Famo from mesoporous silica was studied in simulated intestine fluid (SIF, pH=7.4). For COOH/SBA-15, the release rate of Famo decreased with narrowing pore size. After grafting TMS groups on the surface of COOH/SBA-15 with hexamethyldisilazane, the release of Famo was greatly delayed with the increasing content of TMS groups.

  17. Meticulous Overview on the Controlled Release Fertilizers

    Directory of Open Access Journals (Sweden)

    Siafu Ibahati Sempeho

    2014-01-01

    Full Text Available Owing to the high demand for fertilizer formulations that will exhaust the possibilities of nutrient use efficiency (NUE, regulate fertilizer consumption, and lessen agrophysicochemical properties and environmental adverse effects instigated by conventional nutrient supply to crops, this review recapitulates controlled release fertilizers (CRFs as a cutting-edge and safe way to supply crops’ nutrients over the conventional ways. Essentially, CRFs entail fertilizer particles intercalated within excipients aiming at reducing the frequency of fertilizer application thereby abating potential adverse effects linked with conventional fertilizer use. Application of nanotechnology and materials engineering in agriculture particularly in the design of CRFs, the distinctions and classification of CRFs, and the economical, agronomical, and environmental aspects of CRFs has been revised putting into account the development and synthesis of CRFs, laboratory CRFs syntheses and testing, and both linear and sigmoid release features of CRF formulations. Methodical account on the mechanism of nutrient release centring on the empirical and mechanistic approaches of predicting nutrient release is given in view of selected mathematical models. Compositions and laboratory preparations of CRFs basing on in situ and graft polymerization are provided alongside the physical methods used in CRFs encapsulation, with an emphasis on the natural polymers, modified clays, and superabsorbent nanocomposite excipients.

  18. Hanford Waste Vitrification Plant technical background document for best available radionuclide control technology demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, A.B.; Skone, S.S.; Rodenhizer, D.G.; Marusich, M.V. (Ebasco Services, Inc., Bellevue, WA (USA))

    1990-10-01

    This report provides the background documentation to support applications for approval to construct and operate new radionuclide emission sources at the Hanford Waste Vitrification Plant (HWVP) near Richland, Washington. The HWVP is required to obtain permits under federal and state statutes for atmospheric discharges of radionuclides. Since these permits must be issued prior to construction of the facility, draft permit applications are being prepared, as well as documentation to support these permits. This report addresses the applicable requirements and demonstrates that the preferred design meets energy, environmental, and economic criteria for Best Available Radionuclide Control Technology (BARCT) at HWVP. 22 refs., 11 figs., 25 tabs.

  19. Hanford Waste Vitrification Plant technical background document for best available radionuclide control technology demonstration

    International Nuclear Information System (INIS)

    Carpenter, A.B.; Skone, S.S.; Rodenhizer, D.G.; Marusich, M.V.

    1990-10-01

    This report provides the background documentation to support applications for approval to construct and operate new radionuclide emission sources at the Hanford Waste Vitrification Plant (HWVP) near Richland, Washington. The HWVP is required to obtain permits under federal and state statutes for atmospheric discharges of radionuclides. Since these permits must be issued prior to construction of the facility, draft permit applications are being prepared, as well as documentation to support these permits. This report addresses the applicable requirements and demonstrates that the preferred design meets energy, environmental, and economic criteria for Best Available Radionuclide Control Technology (BARCT) at HWVP. 22 refs., 11 figs., 25 tabs

  20. Behaviour and control of radionuclides in the environment: present state of knowledge and future needs

    International Nuclear Information System (INIS)

    Myttenaere, C.

    1983-01-01

    The Radiation Protection Programme of the European Communities is discussed in the context of the behaviour and control of radionuclides in the environment with reference to the aims of the programme, the results of current research activities and requirements for future studies. The summarised results of the radioecological research activities for 1976 - 1980 include the behaviour of α-emitters (Pu, Am, Cm), 99 Tc, 137 Cs, 144 Ce, 106 Ru and 125 Sb in marine environments; atmospheric dispersion of radionuclides; and the transport of radionuclides in components of freshwater and terrestrial ecosystems. (U.K.)

  1. Assessment of impact of a severe accident at nuclear power plant of Angra dos Reis with release of radionuclides to the atmosphere

    International Nuclear Information System (INIS)

    Aguiar, Andre Silva de

    2015-01-01

    This study had as purpose the assess the impact of a severe accident, and also analyze the dispersion of 131 I in the atmosphere, so that, through concentrating and inhaling dose of the plume, were possible to verify if the results are in accordance with the indicated data by the Plan of Emergency of the CNAAA regarding the Impact Zone and Control. This exercise was performed with the aid of an atmospheric model and a dispersion where to atmospheric modeling we used the data coupling WRF / CALMET and of dispersion, CALPUFF. The suggested accident consists of a Station Blackout at Nuclear Power of Angra (Unit 1), where through the total core involvement, will release 100% of the 131 I to the atmosphere. The value of the total activity in the nucleus to this radionuclide is 7.44 x 1017 Bq, that is relative on the sixth day of burning. This activity will be released through the chimney at a rate in Bq/s in the scenario of 12, 24, 48 and 72 hours of release. Applying the model in the proposed scenario, it is verified that the plume has concentrations of the order of 1020 Bq/m³ and dose of about 108 Sv whose value is beyond of the presented by Eletronuclear in your current emergency plan. (author)

  2. BIODOSE: a code for predicting the dose to man from radionuclides released from underground nuclear waste repositories

    International Nuclear Information System (INIS)

    Bonner, N.A.; Ng, Y.C.

    1980-03-01

    The BIODOSE computer program simulates the environmental transport of radionuclides released to surface water and predicts the resulting dosage to humans. This report describes the program and discusses its use in the evaluation of nuclear waste repositories. The methods used to estimate dose are examined critically, and the most important parameters in each stage of the calculations are identified as an aid in planning for measurements in the field. Dose predictions from releases of nuclear waste to a large northwestern river (the baseline river) are presented to point out the nuclides, compartments and pathways that contribute most to the hazard as a function of waste storage time. Predictions for five other water systems are presented to identify the most important system parameters that determine the concentrations of individual nuclides in compartments and the resultant dose. The uncertainties in the biological parameters for dose prediction are identified, and changes in current values are suggested. Various ways of reporting dose estimates for radiological safety assessments are discussed. Additional work needed to improve the dose predictions from BIODOSE and specific areas and steps to improve our capabilities to assess the environmental transport of nuclides released from nuclear waste repositories and the resultant dose to man are suggested

  3. Selection of critical group in relation to the release of radionuclides from nuclear spent fuel reprocessing plant

    International Nuclear Information System (INIS)

    Ohmomo, Y.

    1980-01-01

    In respect of internal radiation due to the coastal release of radionuclides, survey on marine food consumption is most useful for the selection of critical group. Species of marine organisms they usually eat is fully over 100 in the coastal area of Ibaraki prefecture where the fuel reprocessing plant is located. Though it gives only a spot datum, one day's consumption survey a season is of convenience to obtain cooperation from housewives and is of use to pick up critical organisms and those who eat much of them. However, long-term survey is required to estimate ordinary intake of the critical foods or those who are supposed critical people. One day's consumption survey makes it easy to perform the subsequent long-term one

  4. Deposition of radionuclides and their subsequent relocation in the environment following an accidental release to the atmosphere

    International Nuclear Information System (INIS)

    Underwood, B.Y.; Roed, J.; Paretzke, H.G.

    1993-01-01

    The objective of the project is to improve, as necessary, the models and parameterizations used in estimating the intensity and spatial distribution of deposited activity, and the total health/economic impact of such deposits in assessments of the consequences of accidental releases of radioactivity. The study comprises the influence of various weather conditions on deposition; the resuspension of deposited 137 Cs activity; the weathering of deposits in urban and rural environments; the ultimate fate and dosimetric impact of radionuclides carried by urban run-off water; the impact of the atmosphere's dispersion capabilities. Objectives and results of the four contributions to the project for the reporting period are presented. (R.P.) 5 refs., 4 figs., 1 tab

  5. Summary of estimated doses and risks resulting from routine radionuclide releases from fast breeder reactor fuel cycle facilities

    International Nuclear Information System (INIS)

    Miller, C.W.; Meyer, H.R.

    1985-01-01

    A project is underway at Oak Ridge National Laboratory to assess the human health and environment effects associated with operation of Liquid Metal Fast Breeder Reactor fuel cycle. In this first phase of the work, emphasis was focused on routine radionuclide releases from reactor and reprocessing facilities. For this study, sites for fifty 1-GW(e) capacity reactors and three reprocessing plants were selected to develop scenarios representative of US power requirements. For both the reactor and reprocessing facility siting schemes selected, relatively small impacts were calculated for locality-specific populations residing within 100 km. Also, the results of these analyses are being used in the identification of research priorities. 13 refs., 2 figs., 3 tabs

  6. BLT-EC (Breach, Leach Transport, and Equilibrium Chemistry), a finite-element model for assessing the release of radionuclides from low-level waste disposal units: Background, theory, and model description

    International Nuclear Information System (INIS)

    MacKinnon, R.J.; Sullivan, T.M.; Simonson, S.A.; Suen, C.J.

    1995-08-01

    Performance assessment models typically account for the processes of sorption and dissolution-precipitation by using an empirical distribution coefficient, commonly referred to as K d that combines the effects of all chemical reactions between solid and aqueous phases. In recent years, however, there has been an increasing awareness that performance assessments based solely on empirically based K d models may be incomplete, particularly for applications involving radionuclides having sorption and solubility properties that are sensitive to variations in the in-situ chemical environment. To accommodate variations in the in-situ chemical environment, and to assess its impact on radionuclide mobility, it is necessary to model radionuclide release, transport, and chemical processes in a coupled fashion. This modeling has been done and incorporated into the two-dimensional, finite-element, computer code BLT-EC (Breach, Leach, Transport, Equilibrium Chemistry). BLT-EC is capable of predicting container degradation, waste-form leaching, and advective-dispersive, multispecies, solute transport. BLT-EC accounts for retardation directly by modeling the chemical processes of complexation, sorption, dissolution-precipitation, ion-exchange, and oxidation-reduction reactions. In this report we: (1) present a detailed description of the various physical and chemical processes that control the release and migration of radionuclides from shallow land LLW disposal facilities; (2) formulate the mathematical models that represent these processes; (3) outline how these models are incorporated and implemented in BLT-EC; and (4) demonstrate the application of BLT-EC on a set of example problems

  7. Materials interactions test methods to measure radionuclide release from waste forms under repository-relevant conditions

    International Nuclear Information System (INIS)

    Strickert, R.G.; Erikson, R.L.; Shade, J.W.

    1984-10-01

    At the request of the Basalt Waste Isolation Project, the Materials Characterization Center has collected and developed a set of procedures into a waste form compliance test method (MCC-14.4). The purpose of the test is to measure the steady-state concentrations of specified radionuclides in solutions contacting a waste form material. The test method uses a crushed waste form and basalt material suspended in a synthetic basalt groundwater and agitated for up to three months at 150 0 C under anoxic conditions. Elemental and radioisotopic analyses are made on filtered and unfiltered aliquots of the solution. Replicate experiments are performed and simultaneous tests are conducted with an approved test material (ATM) to help ensure precise and reliable data for the actual waste form material. Various features of the test method, equipment, and test conditions are reviewed. Experimental testing using actinide-doped borosilicate glasses are also discussed. 9 references, 2 tables

  8. Model description. NUDOS: A computer program for assessing the consequences of airborne releases of radionuclides

    International Nuclear Information System (INIS)

    Poley, A.D.

    1996-02-01

    NUDOS is a computer program that can be used to evaluate the consequences of airborne releases of radioactive material. The consequences which can be evaluated are individual dose and associated radiological risk, collective dose and the contamination of land. The code is capable of dealing with both continuous (routine) and accidental releases. For accidental releases both deterministic and probabilistic calculations can be performed, and the impact and effectiveness of emergency actions can be evaluated. This report contains a description of the models contained in NUDOS92 and the recommended values for the input parameters of these models. Additionally, a short overview is given of the future model improvement planned for the next NUDOS-version. (orig.)

  9. Controlled Release Formulations of Auxinic Herbicides

    Science.gov (United States)

    Kowalski, Witold J.; Siłowiecki, Andrzej.; Romanowska, Iwona; Glazek, Mariola; Bajor, Justyna; Cieciwa, Katarzyna; Rychter, Piotr

    2013-04-01

    Controlled release formulations are applied extensively for the release of active ingredients such as plant protection agents and fertilizers in response to growing concern for ecological problems associated with increased use of plant protection chemicals required for intensive agricultural practices [1]. We synthesized oligomeric mixtures of (R,S)-3-hydroxy butyric acid chemically bonded with 2,4-D, Dicamba and MCPA herbicides (HBA) respectively, and determined their molecular structure and molecular weight dispersion by the size exclusion chromatography, proton magnetic resonance spectrometry and electro-spray ionization mass spectrometry. Further we carried out bioassays of herbicidal effectiveness of the HBA herbicides vs. series of dicotyledonous weeds and crop injury tests [2, 3, 4]. Field bioassays were accomplished according to the EPPO standards [5]. Groups of representative weeds (the development stages in the BCCH scale: 10 - 30) were selected as targets. Statistical variabilities were assessed by the Fisher LSD test for plants treated with the studied herbicides in form of HBA oligomers, the reference herbicides in form of dimethyl ammonium salts (DMA), and untreated plants. No statistically significant differences in the crop injuries caused by the HBA vs. the DMA reference formulation were observed. The effectiveness of the HBA herbicides was lower through the initial period (ca. 2 weeks) relative to the DMA salts, but a significant increase in the effectiveness of the HBA systems followed during the remaining fraction of each assay. After 6 weeks all observed efficiencies approached 100%. The death of weeds treated with the HBA herbicides was delayed when compared with the DMA reference herbicides. The delayed uptake observed for the HBA oligomers relative to the DMA salts was due to controlled release phenomena. In case of the DMA salts the total amount of active ingredients was available at the target site. By contrast, the amount of an active

  10. Global Collective Dose Commitments from Release of Long-Lived Radionuclides

    DEFF Research Database (Denmark)

    Gjørup, H. L.

    1977-01-01

    The concept of global collective dose commitment as a measure of total detriment from the release of radioactivity to the environment is outlined. Estimates are given of global collective dose commitments resulting from the release of 14C and uranium daughter products from the nuclear fuel cycle...... that the use of global collective dose commitments in differential cost-benefit analysis can lead to questionable results. In differential cost-benefit analysis it is suggested that population exposures should not simply be integrated irrespective of their time of occurrence, but that a certain discount rate...

  11. Comparison of the COMRADEX-IV and AIRDOS-EPA methodologies for estimating the radiation dose to man from radionuclide releases to the atmosphere

    International Nuclear Information System (INIS)

    Miller, C.W.; Hoffman, F.O.; Dunning, D.E. Jr.

    1981-01-01

    This report presents a comparison between two computerized methodologies for estimating the radiation dose to man from radionuclide releases to the atmosphere. The COMRADEX-IV code was designed to provide a means of assessing potential radiological consequences from postulated power reactor accidents. The AIRDOS-EPA code was developed primarily to assess routine radionuclide releases from nuclear facilities. Although a number of different calculations are performed by these codes, three calculations are in common - atmospheric dispersion, estimation of internal dose from inhalation, and estimation of external dose from immersion in air containing gamma emitting radionuclides. The models used in these calculations were examined and found, in general, to be the same. Most differences in the doses calculated by the two codes are due to differences in values chosen for input parameters and not due to model differences. A sample problem is presented for illustration

  12. Assessment of Westinghouse Hanford Company methods for estimating radionuclide release from ground disposal of waste water at the N Reactor sites

    International Nuclear Information System (INIS)

    1988-09-01

    This report summarizes the results of an independent assessment by Golder Associates, Inc. of the methods used by Westinghouse Hanford Company (Westinghouse Hanford) and its predecessors to estimate the annual offsite release of radionuclides from ground disposal of cooling and other process waters from the N Reactor at the Hanford Site. This assessment was performed by evaluating the present and past disposal practices and radionuclide migration data within the context of the hydrology, geology, and physical layout of the N Reactor disposal site. The conclusions and recommendations are based upon the available data and simple analytical calculations. Recommendations are provided for conducting more refined analyses and for continued field data collection in support of estimating annual offsite releases. Recommendations are also provided for simple operational and structural measures that should reduce the quantities of radionuclides leaving the site. 5 refs., 9 figs., 1 tab

  13. The use of 59Ni, 99Tc, and 236U to monitor the release of radionuclides from objects containing spent nuclear fuel dumped in the Kara Sea

    International Nuclear Information System (INIS)

    Mount, M.E.; Layton, D.W.; Hamilton, T.F.; Lynn, M.

    1999-01-01

    Between 1965 and 1981, five objects and six naval reactor pressure vessels (RPVs) from four former Soviet Union submarines and a special container from the icebreaker Lenin, all containing damaged spent nuclear fuel (SNF) were dumped in a variety of containments, at four sites in the Kara Sea. The International Atomic Energy Agency initiated the International Arctic Seas Assessment Project (IASAP) to study the possible health and environmental effects from disposal of these objects. One outcome of the IASAP was an estimation of the radionuclide inventory and their release rates from these objects. A follow-on concern is the ability to detect the radionuclides released into the water column. The work reported here is the feasibility of using the long-lived radionuclides 59 Ni, 99 Tc, and 236 U encased within these objects, to monitor the breakdown of the containments due to corrosion

  14. Hydrogeological modelling for assessment of radionuclide release scenarios for the repository system 2012

    Energy Technology Data Exchange (ETDEWEB)

    Hartley, L.; Hoek, J.; Swan, D.; Appleyard, P.; Baxter, S.; Roberts, D.; Simpson, T. [AMEC (United Kingdom)

    2013-07-15

    Posiva Oy is responsible for implementing the programme for geological disposal of spent nuclear fuel produced by its owners Teollisuuden Voima Oyj (TVO) and Fortum Power and Heat Oy in Finland. Olkiluoto in Eurajoki has been selected as the primary site for the repository, subject to further detailed investigation which is currently focused on the construction of an underground rock characterisation and research facility (the ONKALO). An essential part of the assessment of long-term safety of a repository is the analysis of groundwater flow since it is the only means of transport of radionuclides to the biosphere (besides human intrusion). The analysis of long-term safety for a KBS-3 concept requires as input a description of details of the groundwater flow around and through components of the engineered barrier system as well as details of the groundwater pathway to the biosphere during the current temperate climate period, as well as indications of behaviour under future climate periods such as glacial conditions. This report describes the groundwater flow modelling study performed to provide some of the necessary inputs required by Safety Assessment (i.e. radionuclide transport analysis). Underlying this study is the understanding of the site developed during the site investigations as summarised in the site descriptive model (SDM), and in particular the description of Olkiluoto Hydrogeological DFN model (Hydro-DFN). The main focus of this study is the temperate climate period, i.e. the evolution over the next 10,000 years, but the hydrogeological situation under various glacial climate conditions is also evaluated. Primary outputs of the study are repository performance measures relating to: the distributions of groundwater flow around the deposition holes; deposition tunnels and through the EDZ; flow-related transport resistance along groundwater pathways from the repository to the surface; and their the exit locations. Other analyses consider the

  15. Hydrogeological modelling for assessment of radionuclide release scenarios for the repository system 2012

    International Nuclear Information System (INIS)

    Hartley, L.; Hoek, J.; Swan, D.; Appleyard, P.; Baxter, S.; Roberts, D.; Simpson, T.

    2013-07-01

    Posiva Oy is responsible for implementing the programme for geological disposal of spent nuclear fuel produced by its owners Teollisuuden Voima Oyj (TVO) and Fortum Power and Heat Oy in Finland. Olkiluoto in Eurajoki has been selected as the primary site for the repository, subject to further detailed investigation which is currently focused on the construction of an underground rock characterisation and research facility (the ONKALO). An essential part of the assessment of long-term safety of a repository is the analysis of groundwater flow since it is the only means of transport of radionuclides to the biosphere (besides human intrusion). The analysis of long-term safety for a KBS-3 concept requires as input a description of details of the groundwater flow around and through components of the engineered barrier system as well as details of the groundwater pathway to the biosphere during the current temperate climate period, as well as indications of behaviour under future climate periods such as glacial conditions. This report describes the groundwater flow modelling study performed to provide some of the necessary inputs required by Safety Assessment (i.e. radionuclide transport analysis). Underlying this study is the understanding of the site developed during the site investigations as summarised in the site descriptive model (SDM), and in particular the description of Olkiluoto Hydrogeological DFN model (Hydro-DFN). The main focus of this study is the temperate climate period, i.e. the evolution over the next 10,000 years, but the hydrogeological situation under various glacial climate conditions is also evaluated. Primary outputs of the study are repository performance measures relating to: the distributions of groundwater flow around the deposition holes; deposition tunnels and through the EDZ; flow-related transport resistance along groundwater pathways from the repository to the surface; and their the exit locations. Other analyses consider the

  16. Study on plutonium distribution in Palomares ecosystem after an accidental aerosol release of transuranic radionuclides

    International Nuclear Information System (INIS)

    Gasco Sanchez, L.

    1990-01-01

    A discharge of plutonium and transuranic elements accidentally ocurred near Palomares (Almeria, Spain) in 1966. After decontamining operations, about 10 g of finely dispersed plutonium remained on the soil and was spreaded on the sorroundings and into Mediterranean sea. An analytical study including a 34 sampling sites of marine sediments, chemical clean-up, analytical methods for isolating plutonium from interfering radionuclides in the alfa-spectra was carried out. The detection limit level reached for the 239 u+ 240 Pu was 10 mBq/Kg one of the lowest cited in the Spanish analytical literature until now. These results were attained following a careful electroplating Pu deposition method developed by our laboratory as result of the high signal/noise rates measured and a 20 KeV resolution. Several analytical assurance quality procedures specially developed for the Palomares ecological system were applied to the results, at the CIEMAT laboratories using reference standard certified samples. The values were unbiased and with no differences statistically significants between them. Interlaboratory comparisons were carried out. After 20 years of plutonium traces environmental transport their concentration were from two at three times the leves of radionuclides in the fallout of the zone studied. The plutonium concentration range in surface sediments was 0.3-5.0 Bq/Kg. The highest values corresponding in the coastal sediments and the lowest in the deep sea. Plutonium concentrations are highly correlated with the sediments structure, grain size composition and distance from the mouth of Almanzora river. The most important contribution at the transport from the land into sea could be the freshet occured at 1973. For this reason the plutonium ecologycal path has been from Palomares sorroundings into the sea. Sites in the Mediterranean sea not affected by plutonium apportation from Almanzora river showed Pu levels approximately the same as the mean value for the whole

  17. 28 CFR 541.50 - Release from a control unit.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Release from a control unit. 541.50... INMATE DISCIPLINE AND SPECIAL HOUSING UNITS Control Unit Programs § 541.50 Release from a control unit. (a) Only the Executive Panel may release an inmate from a control unit. The following factors are...

  18. Seminar on Comparative assessment of the environmental impact of radionuclides released during three major nuclear accidents: Kyshtym, Windscale, Chernobyl. Vol. 1

    International Nuclear Information System (INIS)

    1991-01-01

    These proceedings of seminar on comparative assessment of the environmental impact of radionuclides released during three major nuclear accidents (Kyshtym, Windscale, Chernobyl) are divided into 5 parts bearing on: part 1: accident source terms; part 2: atmospheric dispersion, resuspension, chemical and physical forms of contamination; part 3: environmental contamination and transfer; part 4: radiological implications for man and his environment; part 5: countermeasures

  19. Recommended Parameter Values for GENII Modeling of Radionuclides in Routine Air and Water Releases

    Energy Technology Data Exchange (ETDEWEB)

    Snyder, Sandra F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Arimescu, Carmen [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Napier, Bruce A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hay, Tristan R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2012-11-01

    The GENII v2 code is used to estimate dose to individuals or populations from the release of radioactive materials into air or water. Numerous parameter values are required for input into this code. User-defined parameters cover the spectrum from chemical data, meteorological data, agricultural data, and behavioral data. This document is a summary of parameter values that reflect conditions in the United States. Reasonable regional and age-dependent data is summarized. Data availability and quality varies. The set of parameters described address scenarios for chronic air emissions or chronic releases to public waterways. Considerations for the special tritium and carbon-14 models are briefly addressed. GENIIv2.10.0 is the current software version that this document supports.

  20. A model for short and medium range dispersion of radionuclides released to the atmosphere

    International Nuclear Information System (INIS)

    Clarke, R.H.

    1979-09-01

    A Working Group was established to give practical guidance on the estimation of the dispersion of radioactive releases to the atmosphere. The dispersion is estimated in the short and medium range, that is from about 100 m to a few tens of kilometres from the source, and is based upon a Gaussian plume model. A scheme is presented for categorising atmospheric conditions and values of the associated dispersion parameters are given. Typical results are presented for releases in specific meteorological conditions and a scheme is included to allow for durations of release of up to 24 hours. Consideration has also been given to predicting longer term average concentrations, typically annual averages, and results are presented which facilitate site specific calculations. The results of the models are extended to 100 km from the source, but the increasing uncertainty with which results may be predicted beyond a few tens of kilometres from the source is emphasised. Three technical appendices provide some of the rationale behind the decisions made in adopting the various models in the proposed dispersion scheme. (author)

  1. Tumour control probability (TCP) for non-uniform activity distribution in radionuclide therapy

    International Nuclear Information System (INIS)

    Uusijaervi, Helena; Bernhardt, Peter; Forssell-Aronsson, Eva

    2008-01-01

    Non-uniform radionuclide distribution in tumours will lead to a non-uniform absorbed dose. The aim of this study was to investigate how tumour control probability (TCP) depends on the radionuclide distribution in the tumour, both macroscopically and at the subcellular level. The absorbed dose in the cell nuclei of tumours was calculated for 90 Y, 177 Lu, 103m Rh and 211 At. The radionuclides were uniformly distributed within the subcellular compartment and they were uniformly, normally or log-normally distributed among the cells in the tumour. When all cells contain the same amount of activity, the cumulated activities required for TCP = 0.99 (A-tilde TCP=0.99 ) were 1.5-2 and 2-3 times higher when the activity was distributed on the cell membrane compared to in the cell nucleus for 103m Rh and 211 At, respectively. TCP for 90 Y was not affected by different radionuclide distributions, whereas for 177 Lu, it was slightly affected when the radionuclide was in the nucleus. TCP for 103m Rh and 211 At were affected by different radionuclide distributions to a great extent when the radionuclides were in the cell nucleus and to lesser extents when the radionuclides were distributed on the cell membrane or in the cytoplasm. When the activity was distributed in the nucleus, A-tilde TCP=0.99 increased when the activity distribution became more heterogeneous for 103m Rh and 211 At, and the increase was large when the activity was normally distributed compared to log-normally distributed. When the activity was distributed on the cell membrane, A-tilde TCP=0.99 was not affected for 103m Rh and 211 At when the activity distribution became more heterogeneous. A-tilde TCP=0.99 for 90 Y and 177 Lu were not affected by different activity distributions, neither macroscopic nor subcellular

  2. Balance and behavior of gaseous radionuclides released during initial PWR fuel reprocessing operations

    International Nuclear Information System (INIS)

    Leudet, A.; Miquel, P.; Goumondy, P.J.; Charrier, G.

    1982-08-01

    Five fuel pins, taken from a PWR fuel assembly with 32000 MWD/t burn-up were chopped and dissolved in leak-proof equipment designed for accurate determination of the composition and quantity of gaseous elements released in these operations. Analytical methods were specially developped to determine directly the noble gases, tritium and gaseous carbon compounds in the gas phase. Volatile iodine was kept as close as possible to the source by cold traps, then transferred to a caustic solution for quantitative analysis. The quantities and activities of gaseous fission products thus determined were compared with predicted values obtained through computation. Very good agreement was generally observed

  3. Balance and behavior of gaseous radionuclides released during initial PWR fuel reprocessing operations

    International Nuclear Information System (INIS)

    Leudet, A.; Miquel, P.; Goumondy, P.J.; Charrier, G.

    1983-01-01

    Five fuel pins, taken from a PWR fuel assembly with 32,000 MwD/t burn-up were chopped and dissolved in leak-proof equipment designed for accurate determination of the composition and quantity of gaseous elements released in these operations. Analytical methods were specially developed to determine directly the noble gases, tritium and gaseous carbon compounds in the gas phase. Volatile iodine was kept as close as possible to the source by cold traps, then transferred to a caustic solution for quantitative analysis. The quantities and activities of gaseous fission products thus determined were compared with predicted values obtained through computation. Very good agreement was generally observed

  4. Radionuclide release calculations for selected severe accident scenarios. PWR, ice condenser design

    Energy Technology Data Exchange (ETDEWEB)

    Denning, R S; Gieseke, J A; Cybulskis, P; Lee, K W; Jordan, H; Curtis, L A; Kelly, R F; Kogan, V; Schumacher, P M

    1986-07-01

    This report presents results of analyses of the environmental releases of fission products (source terms) for severe accident scenarios in a pressurized water reactor with an ice-condenser containment. The analyses were performed to support the Severe Accident Risk Reduction/Risk Rebaselining Program (SARRP) which is being undertaken for the U.S. Nuclear Regulatory Commission by Sandia National Laboratories. In the SARRP program, risk estimates are being generated for a number of reference plant designs. The Sequoyah Plant has been used in this study as an example of a PWR ice-condenser plant. (author)

  5. Radionuclide release calculations for selected severe accident scenarios. Volume 3. PWR, subatmospheric containment design

    International Nuclear Information System (INIS)

    Denning, R.S.; Gieseke, J.A.; Cybulskis, P.; Lee, K.W.; Jordan, H.; Curtis, L.A.; Kelly, R.F.; Kogan, V.; Schumacher, P.M.

    1986-07-01

    This report presents results of analyses of the enviromental releases of fission products (source terms) for severe accident scenarios in a pressurized water reactor with a subatmospheric containment design. The analyses were performed to support the Severe Accident Risk Reduction/Risk Rebaselining Program (SARRP) which is being undertaken for the US Nuclear Regulatory Commission by Sandia National Laboratories. In the SARRP program, risk estimates are being generated for a number of reference plant designs. the Surry plant has been used in this study as the reference plant for a subatmospheric design

  6. RESUS: A code for low volatile radio-nuclide release from liquids due to vapor bubble burst induced liquid jet formation and disintegration

    International Nuclear Information System (INIS)

    Koch, M.K.; Starflinger, J.; Linnemann, Th.; Brockmeier, U.; Unger, H.; Schuetz, W.

    1995-01-01

    In the field of nuclear safety, the release of volatile and low volatile radio-nuclides from liquid surfaces into a gas atmosphere is important for aerosol source term considerations particularly in late severe accident sequences. In case of a hypothetical nuclear reactor accident involving a failure of the primary system, primary coolant and radio-nuclides may be released into the containment to frequently form a liquid pool which may be contaminated by suspended or solved fuel particles and fission products. Under this scope, the release code package REVOLS/RENONS was developed for radio-nuclide release from liquid surfaces. Assuming the absence of gas or vapor bubbles in the liquid, the evaporative release of volatile components, calculated by the REVOLS code, is governed by diffusive and convective transport processes, whereas the release of low volatiles, calculated by the RENONS code, may be governed by mechanical processes which leads to droplet entrainment in case of wavy liquid pool surface conditions into the containment atmosphere by means of convection. For many accident sequences, in which gas is injected into a pool or liquid area elsewhere, predominantly when saturation temperatures can be reached, the release of low volatile species from liquid surfaces due to bubble burst is identified as a decisive release mechanism also. Together with the liquid, the particles which are located at the pool surface or suspended in the pool, are released into the atmosphere. Consequently, the code RESUS.MOD1 (RESUSpension) is presently extended to include the calculation of the release of droplets and suspended radio-nuclide particles due to bubble burst induced liquid jet formation and disintegration above liquid surfaces. Experimental investigations indicate the influence of bubble volume and shape at the pool surface as well as bubble stabilization or destabilization, and furthermore the system pressure and temperatures as well as fluid properties, on droplet

  7. Effect of pH on the release of radionuclides and chelating agents from cement-solidified decontamination ion-exchange resins collected from operating nuclear power stations

    International Nuclear Information System (INIS)

    McIsaac, C.V.; Akers, D.W.; McConnell, J.W.

    1991-06-01

    Data are presented on the physical stability and leachability of radionuclides and chelating agents from cement-solidified decontamination ion-exchange resin wastes collected from two operating commercial light water reactors. Small-scale waste--form specimens collected during solidifications performed at the Brunswick Steam Electric Plant Unit 1 and at the James A. FitzPatrick Nuclear Power Station were leach-tested and subjected to compressive strength testing in accordance with the Nuclear Regulatory Commission's ''Technical Position on Waste Form'' (Revision 1). Samples of untreated resin waste collected from each solidification vessel before the solidification process were analyzed for concentrations of radionuclides, selected transition metals, and chelating agents to determine the quantities of these chemicals in the waste-form specimens. The chelating agents included oxalic, citric, and picolinic acids. In order to determine the effect of leachant chemical composition and pH on the stability and leachability of the waste forms, waste-form specimens were leached in various leachants. Results of this study indicate that differences in pH do not affect releases from cement-solidified decontamination ion-exchange resin waste forms, but that differences in leachant chemistry and the presence of chelating agents may affect the releases of radionuclides and chelating agents. Also, this study indicates that the cumulative releases of radionuclides and chelating agents are similar for waste- form specimens that decomposed and those that retained their general physical form. 36 refs., 60 figs., 28 tabs

  8. Cenotic and physiological control of the radionuclides migration into system soil-plant

    International Nuclear Information System (INIS)

    Kravets, A.P.

    1998-01-01

    Some biological - cenotic and physiological - factors which determine the availability of radionuclides for a plant and the general capacity for the accumulation of pollutants were investigated and analysed. Metabolites of soil microorganisms and especially root excretion of higher plants increase the rate of destruction of solid forms of pollution and enhance the leaching of radionuclides from the solid matrix. The following facts were demonstrated in the conditions of contamination heterogeneity of Chernobyl fallout: (i) During the period of vegetation the plants of different species of f. Poacea, 1 .5 to 2.7-fold increase in the chemical mobility and biological availability of radionuclides; (ii) Additional increase in the concentration of soil microorganisms (micromycetes) leads to enhanced contents of the mobile form of the pollutant in soil and increases the level of accumulation of the radionuclides by higher plants; (iii) Increase in the density of sowing (and competition, respectively) of the different species of the plants also leads to an enhanced availability of the radionuclides and 1 .7 to 2.4- fold increase in the level of accumulation of the radionuclides by the plants. Other aspect of formation of the level of plant pollution include the peculiarities of radionuclide absorption and accumulation by the plant biomass. The effects of a high density of sowing, high level of the watering and gamma irradiation on the changes in the level of radionuclide accumulation and, at the same time, the cation exchange capacity (CEC) of the plant biomass were investigated in the laboratory and in a greenhouse experiment. In parallel, increased CEC and radionuclide accumulation by a factor of 1.5 to 2.7 was demonstrated. These facts suggest that the biological factors are a powerful tool of control of the pollutants availability and accumulation and may be take into account under development of the modern agricultural technology for clear products formation

  9. Absorption of controlled-release iron

    International Nuclear Information System (INIS)

    Cook, J.D.; Lipschitz, D.A.; Skikne, B.S.

    1982-01-01

    A multiple-dose double radioiron technic was used to compare absorption of iron administered as a controlled release (CR) capsule and as an elixir; both formulations contained 50 mg elemental iron as ferrous sulfate. When taken by normal subjects in the fasting state, mean absorption from the elixir and CR capsule averaged 4.92% and 4.38%, which gave a CR capsule:elixir ratio of 0.89. This difference was not significant, but when taken with meals that inhibit absorption of dietary iron by different degrees, absorption of the CR formulation was superior. CR capsule:elixir absorption ratios averaged 1.70 from a meal that is mildly inhibitory and 3.13 from a meal that causes more marked inhibition. It is concluded that CR iron formulations may offer a therapeutic advantage to patients who take oral iron with meals to avoid gastrointestinal side effects

  10. Radionuclide release from simulated waste material after biogeochemical leaching of uraniferous mineral samples

    International Nuclear Information System (INIS)

    Williamson, Aimee Lynn; Caron, François; Spiers, Graeme

    2014-01-01

    Biogeochemical mineral dissolution is a promising method for the released of metals in low-grade host mineralization that contain sulphidic minerals. The application of biogeochemical mineral dissolution to engineered leach heap piles in the Elliot Lake region may be considered as a promising passive technology for the economic recovery of low grade Uranium-bearing ores. In the current investigation, the decrease of radiological activity of uraniferous mineral material after biogeochemical mineral dissolution is quantified by gamma spectroscopy and compared to the results from digestion/ICP-MS analysis of the ore materials to determine if gamma spectroscopy is a simple, viable alternative quantification method for heavy nuclides. The potential release of Uranium (U) and Radium-226 ( 226 Ra) to the aqueous environment from samples that have been treated to represent various stages of leaching and passive closure processes are assessed. Dissolution of U from the solid phase has occurred during biogeochemical mineral dissolution in the presence of Acidithiobacillus ferrooxidans, with gamma spectroscopy indicating an 84% decrease in Uranium-235 ( 235 U) content, a value in accordance with the data obtained by dissolution chemistry. Gamma spectroscopy data indicate that only 30% of the 226 Ra was removed during the biogeochemical mineral dissolution. Chemical inhibition and passivation treatments of waste materials following the biogeochemical mineral dissolution offer greater protection against residual U and 226 Ra leaching. Pacified samples resist the release of 226 Ra contained in the mineral phase and may offer more protection to the aqueous environment for the long term, compared to untreated or inhibited residues, and should be taken into account for future decommissioning. - Highlights: • Gamma counting showed an 84% decrease in 235 U after biogeochemical mineral leaching. • Chemical digestion/ICP-MS analysis also showed an 84% decrease in total U. • Over

  11. Operational control of material release and discharges from nuclear power plant

    International Nuclear Information System (INIS)

    Szabo, I. C.; Ranga, T.; Daroczi, L.; Deme, S.; Kerekes, A.

    2003-01-01

    The operational control of radioactive materials during atmospheric release and aquatic discharge from nuclear power plant is a licensing criterion for NPPs. Originally at the Paks NPP the release control was based on activity limits for four groups of elements. These groups were noble gases, long living radio-aerosols, radioiodine and radiostrontium for atmospheric release and specified activity limit for beta emitters, strontium and tritium for aquatic discharge into Danube. These groups were controlled with proper sampling and/or measuring instrumentation. The limit for atmospheric release was given as a 30-day moving average, for liquid discharges the annual limit was stipulated. The new release and discharge limitation system is based on the environmental dose limitation. The dose constraint for Paks NPP is 90 Sv/year of the critical group for all release pathways and the investigation dose limit is equal to 27 Sv/year. The regulation did not subdivide the dose limit for atmospheric and liquid components but for operational control subdivision of dose limits for atmospheric release and aquatic discharge and shorter time period (one day-one month) seems to be useful. The subdivision can be based on past release data and/or previous activity limits. To satisfy dose below the investigation dose limit there should be a proper operation control level for each separately measured component and pathway belonging to reasonable time interval significantly shorter than one year. The main task of the NPP staff is elaboration of reasonable control levels and reference time intervals for different radionuclide and element groups to be used in operational control. Operational control levels are based on measured daily or monthly release rates. In case of noble gases, aerosols and iodine the daily release rates have several sharp peaks per year. Operational control levels give opportunity to detect these peaks for internal investigation purposes. Investigation release limits

  12. Generic models and parameters for assessing the environmental transfer of radionuclides from routine releases

    International Nuclear Information System (INIS)

    1982-01-01

    This report is addressed to national regulatory bodies and technical and administrative personnel responsible for performing environmental impact analyses, in particular for generic assessments of doses to most exposed individuals from routine releases of radioactive effluents to atmospheric and aquatic environments. The concern of society in general for the quality of the environment and the realization that all human activities have some environmental effect, in which actions and reactions are coupled in a complex but predictable manner, have led to the development of a procedure for environmental impact analysis. This procedure is a predictive one, which tries to forecast probable environmental effects before some action, such as the construction and operation of a nuclear power station, is decided upon. The method of prediction is by the application of models that attempt to describe the environmental processes in mathematical terms in order to produce a quantitative result which can be used in the decision-making process

  13. Forecasting the consequences of accidental releases of radionuclides in the atmosphere from ensemble dispersion modelling

    International Nuclear Information System (INIS)

    Galmarini, S.; Bianconi, R.; Bellasio, R.; Graziani, G.

    2001-01-01

    The RTMOD system is presented as a tool for the intercomparison of long-range dispersion models as well as a system for support of decision making. RTMOD is an internet-based procedure that collects the results of more than 20 models used around the world to predict the transport and deposition of radioactive releases in the atmosphere. It allows the real-time acquisition of model results and their intercomparison. Taking advantage of the availability of several model results, the system can also be used as a tool to support decision making in case of emergency. The new concept of ensemble dispersion modelling is introduced which is the basis for the decision-making application of RTMOD. New statistical parameters are presented that allow gathering the results of several models to produce a single dispersion forecast. The devised parameters are presented and tested on the results of RTMOD exercises

  14. Environmental behavior of the radionuclides released from the Fukushima Daiichi Nuclear Power Plant accident

    International Nuclear Information System (INIS)

    Yamazaki, Hideo

    2014-01-01

    The environmental behavior of radioactive nuclides released from the Fukushima Daiichi Nuclear Power Station (FDNPS) accident in eastern Japan was investigated. The radioactive pollution of environmental samples, including airborne dust, soil, sediment, fish, and other organisms was described. It was evaluated for environmental behavior and fate of the radioactive material from the spatial and temporal distribution of the radioactive nuclides. In Higashiosaka City about 600 km away from FDNPS, it begins to detect the radioactive nuclides in the airborne dust from 25th March 2011. Radioactive fission products 95 Zr- 95 Nb was detected on 18th April. The concentrations of 131 I, 134 Cs, and 137 Cs in the soil collected from Fukushima City were 126000, 14000, and 14200 Bq/kg on 19th March 2011 and 12800, 13200, and 13700 Bq/kg on 26th March 2011, respectively. The concentrations of 131 I, 134 Cs, and 137 Cs in the soil samples collected from March-June 2011 from study sites in metropolitan area and Kanto region ranged from nd to 91900, 59 to 16100, and 69 to 17600 Bq/kg, respectively. (Concentrations of 131 I were done decay correction to the value of 16th March) Radioactivities in fish samples collected from off FDNPS, Tokyo Bay, and Kejonuma Pond were measured. The radioactive contamination of forest ecosystem was also investigated. Two processes are involved in the radioactive contamination of the environment from the FDNPS accident. One is contamination by radioactive nuclides released from the hydrogen explosion. Leakage of contaminated cooling water to the ocean is in other important environmental pollution. We must continue carefully monitoring of radioactive nuclides in the environment. (author)

  15. The radiological situation at the atolls of Mururoa and Fangataufa. Technical report. V. 4. Releases to the biosphere of radionuclides from underground nuclear weapon tests at the atolls

    International Nuclear Information System (INIS)

    1998-08-01

    This report is Volume 4 in the series of 6 volumes of the Technical Report on the radiological situation at the atolls of Mururoa and the Fangataufa. It is the second of the three volumes dealing with the evaluation of the long term radiological situation as a consequence of radionuclide migration from underground sources, which is the responsibility of Task Group B. This volume is based on the activities of Working Group 4 and uses, as its primary input on radionuclide inventories the report of Working Group 3, which is Vol. 3 in this series of Technical Report. Nuclear testing in the atmosphere, outer space and under open ocean was prohibited by the Limited Test Ban Treaty of 5 August 1963 and signed by UK, USA and USSR. France ceased atmospheric testing in September 1974. Isolation from the biosphere in geological formations, or containment in geological formations, became the preferred alternative. The explosion of 137 underground nuclear devices in Mururoa and Fangataufa over the testing period 1975-1996, together with 10 safety trials and the burial of radioactively contaminated material gathered from the atoll surfaces, has resulted in a substantial accumulation of radionuclides in the rock beneath the two atolls. Assessment of the rate at which these radionuclides move from the cavities to the environment accessible to humans, or biosphere and the total radionuclide release to the biosphere over time is the central effort of this Study. The rock mass within which the radionuclides are initially deposited, and which serves to contain or delay release of the radionuclides, will be referred to as the geosphere to distinguish it from the biosphere, where the radionuclides would be accessible either directly or through the food chain to the living environment. This assessment of geosphere transport has been divided into the following four interrelated tasks: (a) Geological Pathways; (b) Hydrological Modelling; (c) Solution Source Term; and (d) Geosphere

  16. Graphic displays on PCs of gaseous diffusion models of radionuclide releases to the atmosphere

    International Nuclear Information System (INIS)

    Campo Ortega, E. del

    1993-01-01

    The well-known MESOI program has been modified and improved to adapt it to a PC/AT with VGA colour monitor. Far from losing any of its powerful characteristics to calculate the transport, diffusion, deposition and decay of gaseous radioactive effluents discharged to the atmosphere, it has been enhanced to allow graphic viewing of concentrations, wind speed and direction and puff locations in colour, all on a background map of the site. The background covers a 75 x 75 km square and has a graphic grid density of 421 x 421 pixels. This means that effluent concentration is represented approximately every 170 metres in the 'clouded-area'. Among the modifications and enhancements made, the following are of particular interest: 1. A new subroutine called NUBE has been added, which calculates the distribution of effluent concentration of activity in a grid of 421 x 421 pixels. 2. Several subroutines have been added to obtain graphic displays and printouts of the cloud, wind field and puff locations. 3. Graphic display of the geographic plane of the area surrounding the effluent release point. 4. Off-line preparation of meteorological and topographical data files necessary for program execution. (author)

  17. Transport in biosphere of radionuclides released from finally disposed nuclear waste - background information for transport and dose model

    International Nuclear Information System (INIS)

    Hulmi, R.; Savolainen, I.

    1981-07-01

    An outline is made about the biosphere transport and dose models employed in the estimation of doses due to releases from finally disposed nuclear waste. The models often divide into two parts; the first one describes the transport of radionuclides in those parts of biosphere where the time scale is large (e.g. soil, sea and sea sediment), the second part of the model describes the transport of nuclides in the systems where the time scale is small (e.g. food chains, plants and animals). The description of biosphere conditions includes remarkable uncertainty due to the complexity of the biosphere and its ecosystems. Therefore studies of scenario type are recommended: some values of parametres describing the conditions are assumed, and the consequences are estimated by using these values. The effect of uncertainty in various factors on the uncertainty of final results should be investigated with the employment of alternative scenarios and parametric sensitivity studies. In addition to the ordinary results, intermediate results should be presented. A proposal for the structure of a transport and dose program based on dynamic linear compartment model is presented and mathematical solution alternatives are studied also

  18. Biogeochemical Processes Controlling Microbial Reductive Precipitation of Radionuclides

    International Nuclear Information System (INIS)

    Fredrickson, James K.; Brooks, Scott C.

    2004-01-01

    This project is focused on elucidating the principal biogeochemical reactions that govern the concentrations, chemical speciation, and distribution of the redox sensitive contaminants uranium (U) and technetium (Tc) between the aqueous and solid phases. The research is designed to provide new insights into the under-explored areas of competing geochemical and microbiological oxidation-reduction reactions that govern the fate and transport of redox sensitive contaminants and to generate fundamental scientific understanding of the identity and stoichiometry of competing microbial reduction and geochemical oxidation reactions. These goals and objectives are met through a series of hypothesis-driven tasks that focus on (1) the use of well-characterized microorganisms and synthetic and natural mineral oxidants, (2) advanced spectroscopic and microscopic techniques to monitor redox transformations of U and Tc, and (3) the use of flow-through experiments to more closely approximate groundwater environments. The results are providing an improved understanding and predictive capability of the mechanisms that govern the redox dynamics of radionuclides in subsurface environments. For purposes of this poster, the results are divided into three sections: (1) influence of Ca on U(VI) bioreduction; (2) localization of biogenic UO 2 and TcO 2 ; and (3) reactivity of Mn(III/IV) oxides.

  19. Development of a general model to predict the rate of radionuclide release (source term) from a low-level waste shallow land burial facility

    International Nuclear Information System (INIS)

    Sullivan, T.M.; Kempf, C.R.; Suen, C.J.; Mughabghab, S.M.

    1988-01-01

    Federal Code of Regulations 10 CFR 61 requires that any near surface disposal site be capable of being characterized, analyzed, and modeled. The objective of this program is to assist NRC in developing the ability to model a disposal site that conforms to these regulations. In particular, a general computer model capable of predicting the quantity and rate of radionuclide release from a shallow land burial trench, i.e., the source term, is being developed. The framework for this general model has been developed and consists of four basic compartments that represent the major processes that influence release. These compartments are: water flow, container degradation, release from the waste packages, and radionuclide transport. Models for water flow and radionuclide transport rely on the use of the computer codes FEMWATER and FEMWASTE. These codes are generally regarded as being state-of-the-art and required little modification for their application to this project. Models for container degradation and release from waste packages have been specifically developed for this project. This paper provides a brief description of the models being used in the source term project and examples of their use over a range of potential conditions. 13 refs

  20. Controlled Release Formulation of Indomethacin Prepared With Bee ...

    African Journals Online (AJOL)

    Erah

    2010-12-27

    Dec 27, 2010 ... Results: The results show that, although the release rate of formulations F1 - F7 did not show any ... Keywords: Propolis (bee glue), Indomethacin, Controlled release, Zero order kinetics, Waxy materials ... focus of interest.

  1. The foundation of computer based closed radionuclide sources turnover control system in Moscow city region

    International Nuclear Information System (INIS)

    Gusev, A.E.; Kozlov, A.A.; Lavrov, K.N.; Sobolev, I.A.

    1998-01-01

    This paper concerns the problem of Closed Radionuclide Sources (CRS) automated account and control in Moscow city and Moscow region. Information relations structure between authorities and enterprises is shown. Special computer oriented system of CRS turnover monitoring is used for this purposes. Its possibilities and numeric characteristics of database are mentioned. This system benefit and application aspects are discussed in detail. (author)

  2. Testing the behaviour of different kinetic models for uptake/release of radionuclides between water and sediments when implemented in a marine dispersion model

    International Nuclear Information System (INIS)

    Perianez, R.

    2004-01-01

    Three kinetic models for adsorption/release of 137 Cs between water and sediments have been tested when they are included in a previously validated dispersion model of the English Channel. Radionuclides are released to the Channel from La Hague nuclear fuel reprocessing plant (France). The kinetic models are a 1-step model consisting of a single reversible reaction, a 2-step model consisting of two consecutive reversible reactions and an irreversible model consisting of three parallel reactions: two reversible and one irreversible. The models have been tested under three typical situations that correspond to the source terms that can generally be found: instantaneous release, continuous release and redissolution of radionuclides from contaminated sediments. Differences between the models become more evident when contact times between water and sediments are larger (continuous release) and in the case of redissolution from sediments. Time scales for the redissolution process are rather different between the three models. The 1-step model produces a redissolution that is too fast when compared with experimental evidence. The irreversible model requires that saturation effects of the irreversible phase are included. Probably, the 2-step model represents the best compromise between ease and level of detail of the description of sorption/release processes

  3. Simplified analytical model to simulate radionuclide release from radioactive waste trenches; Modelo simplificado para simulacao da liberacao de radionuclideos de repositorios de rejeitos radioativos

    Energy Technology Data Exchange (ETDEWEB)

    Sa, Bernardete Lemes Vieira de

    2001-07-01

    In order to evaluate postclosure off-site doses from low-level radioactive waste disposal facilities, a computer code was developed to simulate the radionuclide released from waste form, transport through vadose zone and transport in the saturated zone. This paper describes the methodology used to model these process. The radionuclide released from the waste is calculated using a model based on first order kinetics and the transport through porous media was determined using semi-analytical solution of the mass transport equation, considering the limiting case of unidirectional convective transport with three-dimensional dispersion in an isotropic medium. The results obtained in this work were compared with other codes, showing good agreement. (author)

  4. Controlled-release oxycodone-induced seizures.

    Science.gov (United States)

    Klein, Moti; Rudich, Zvia; Gurevich, Boris; Lifshitz, Matityahu; Brill, Silviu; Lottan, Michael; Weksler, Natan

    2005-11-01

    The use of the opioid oxycodone hydrochloride in the management of chronic pain is gaining popularity principally because of its tolerability. However, opioid-related seizure in patients with epilepsy or other conditions that may decrease seizure threshold has been described in the literature; in particular, oxycodone has been associated with seizure in a patient with acute renal failure. The aim of this article was to report a patient with a history of seizures but normal renal and hepatic function who developed seizure on 2 occasions after oxycodone ingestion. A 54-year-old male patient presented with a history of tonic-clonic seizures that developed immediately after intracranial surgery. Long-term treatment with carbamazepine 400 mg QD was started, and the patient was free of convulsions for approximately 7 years. The patient presented to us with severe headache that was nonresponsive to an NSAID and the opiate agonist tramadol. Treatment with controlled-release (CR) oxycodone and tramadol drops (50 mg QID if necessary) was started, and tonic-clonic seizures developed 3 days later. Based on laboratory analysis, the patient had normal renal and hepatic function. On discontinuation of oxycodone treatment, the seizures resolved. However, due to effective pain relief with oxycodone, the patient decided to continue treatment, and seizures recurred. Carbamazepine was then administered 4 hours before oxycodone dosing, which allowed continuation of treatment without seizure. A patient with a history of seizures controlled with long-term carbamazepine therapy developed seizures when he started treatment with oxycodone CR at recommended doses. Oxycodone CR should be used with extreme caution in patients with epilepsy or other conditions that may decrease seizure threshold.

  5. A review of the role of colloids in the release and transport of radionuclides in the near and far field. Pt. 3

    International Nuclear Information System (INIS)

    Tipping, E.; Higgo, J.J.W.

    1992-01-01

    The role of colloids in the release and transport of radionuclides in the near and far field is discussed and DOE and Nirex funded work is compared with relevant studies by other workers. Gaps in the DOE and Nirex programmes are identified and suggestions for further research are made. This is Part 3 of a three-part review. Part 1 reviews fundamental theory and DOE and Nirex funded work and Part 2 is a comprehensive bibliography (with abstracts). (Author)

  6. Determining the Release of Radionuclides from Tank 18F Waste Residual Solids: FY2016 Report

    Energy Technology Data Exchange (ETDEWEB)

    King, William D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hobbs, David T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-08-12

    Pore water leaching studies were conducted on actual Savannah River Site (SRS) Tank 18F residual waste solids to support Liquid Waste tank closure efforts. A test methodology was developed during previous simulant testing to produce slurries of tank residual solids and grout-representative solids in grout pore water solutions (based on SRS groundwater compositions) with pH and Eh values expected during the aging of the closed waste tank. The target conditions are provided below where the initial pore water has a reducing potential and a relatively high pH (Reducing Region II). The pore water is expected to become increasingly oxidizing with time (Oxidizing Region II) and during the latter stages of aging (Oxidizing Region III) the pH is expected to decrease. For the reducing case, tests were conducted with both unwashed and washed Tank 18F residual solids. For the oxidizing cases (Oxidizing Regions II and III), all samples were washed with simulated grout pore water solutions prior to testing, since it is expected that these conditions will occur after considerable pore water solution has passed through the system. For the reducing case, separate tests were conducted with representative ground grout solids and with calcium carbonate reagent, which is the grout phase believed to be controlling the pH. Ferrous sulfide (FeS) solids were also added to the reducing samples to lower the slurry Eh value. Calcium carbonate solids were used as the grout-representative solid phase for each of the oxidizing cases. Air purge-gas with and without CO2 removed was transferred through the oxidizing test samples and nitrogen purge-gas was transferred through the reducing test samples during leach testing. The target pH values were achieved to within 0.5 pH units for all samples. Leaching studies were conducted over an Eh range of approximately 0.7 V. However, the highest and lowest Eh values achieved of ~+0.5 V and ~-0.2 V were

  7. Determining the release of radionuclides from tank waste residual solids. FY2015 report

    Energy Technology Data Exchange (ETDEWEB)

    King, William D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hobbs, David T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-09-11

    Methodology development for pore water leaching studies has been continued to support Savannah River Site High Level Waste tank closure efforts. For FY2015, the primary goal of this testing was the achievement of target pH and Eh values for pore water solutions representative of local groundwater in the presence of grout or grout-representative (CaCO3 or FeS) solids as well as waste surrogate solids representative of residual solids expected to be present in a closed tank. For oxidizing conditions representative of a closed tank after aging, a focus was placed on using solid phases believed to be controlling pH and Eh at equilibrium conditions. For three pore water conditions (shown below), the target pH values were achieved to within 0.5 pH units. Tank 18 residual surrogate solids leaching studies were conducted over an Eh range of approximately 630 mV. Significantly higher Eh values were achieved for the oxidizing conditions (ORII and ORIII) than were previously observed. For the ORII condition, the target Eh value was nearly achieved (within 50 mV). However, Eh values observed for the ORIII condition were approximately 160 mV less positive than the target. Eh values observed for the RRII condition were approximately 370 mV less negative than the target. Achievement of more positive and more negative Eh values is believed to require the addition of non-representative oxidants and reductants, respectively. Plutonium and uranium concentrations measured during Tank 18 residual surrogate solids leaching studies under these conditions (shown below) followed the general trends predicted for plutonium and uranium oxide phases, assuming equilibrium with dissolved oxygen. The highest plutonium and uranium concentrations were observed for the ORIII condition and the lowest concentrations were observed for the RRII condition. Based on these results, it is recommended that these test methodologies be used to

  8. Joint release rate estimation and measurement-by-measurement model correction for atmospheric radionuclide emission in nuclear accidents: An application to wind tunnel experiments.

    Science.gov (United States)

    Li, Xinpeng; Li, Hong; Liu, Yun; Xiong, Wei; Fang, Sheng

    2018-03-05

    The release rate of atmospheric radionuclide emissions is a critical factor in the emergency response to nuclear accidents. However, there are unavoidable biases in radionuclide transport models, leading to inaccurate estimates. In this study, a method that simultaneously corrects these biases and estimates the release rate is developed. Our approach provides a more complete measurement-by-measurement correction of the biases with a coefficient matrix that considers both deterministic and stochastic deviations. This matrix and the release rate are jointly solved by the alternating minimization algorithm. The proposed method is generic because it does not rely on specific features of transport models or scenarios. It is validated against wind tunnel experiments that simulate accidental releases in a heterogonous and densely built nuclear power plant site. The sensitivities to the position, number, and quality of measurements and extendibility of the method are also investigated. The results demonstrate that this method effectively corrects the model biases, and therefore outperforms Tikhonov's method in both release rate estimation and model prediction. The proposed approach is robust to uncertainties and extendible with various center estimators, thus providing a flexible framework for robust source inversion in real accidents, even if large uncertainties exist in multiple factors. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Dual-controlled release system of drugs for bone regeneration.

    Science.gov (United States)

    Kim, Yang-Hee; Tabata, Yasuhiko

    2015-11-01

    Controlled release systems have been noted to allow drugs to enhance their ability for bone regeneration. To this end, various biomaterials have been used as the release carriers of drugs, such as low-molecular-weight drugs, growth factors, and others. The drugs are released from the release carriers in a controlled fashion to maintain their actions for a long time period. Most research has been focused on the controlled release of single drugs to demonstrate the therapeutic feasibility. Controlled release of two combined drugs, so-called dual release systems, are promising and important for tissue regeneration. This is because the tissue regeneration process of bone formation is generally achieved by multiple bioactive molecules, which are produced from cells by other molecules. If two types of bioactive molecules, (i.e., drugs), are supplied in an appropriate fashion, the regeneration process of living bodies will be efficiently promoted. This review focuses on the bone regeneration induced by dual-controlled release of drugs. In this paper, various dual-controlled release systems of drugs aiming at bone regeneration are overviewed explaining the type of drugs and their release materials. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Environmental Release Prevention and Control Plan

    International Nuclear Information System (INIS)

    Mamatey, A.; Arnett, M.

    1997-01-01

    During the history of SRS, continual improvements in facilities, process, and operations, and changes in the site''s mission have reduced the amount of radioactive liquid releases. In the early years of SRS (1958 to 1965), the amount of tritium discharged to the Savannah River averaged approximately 61,000 curies a year. During the mid-1980''s (1983 to 1988), liquid releases of tritium averaged 27,000 curies a year. By 1996, liquid releases of tritium are projected to be just 3000 curies for the year. This large projected decrease is the result of the planned shut-down of all reactors and the anticipated significant decline in the amount of tritium migrating from the site seepage basins and the Solid Waste Disposal Facility

  11. Nanocomposites for controlled release of nitrogen fertilizer

    International Nuclear Information System (INIS)

    Silva, Viviane J.M. da; Visconte, Leila L.Y.; Nascimento, Regina Sandra V.

    2009-01-01

    The study aimed at the development of nano structured materials capable of reducing the rate of release of nitrogen in the soil from an agricultural nitrogen fertilizer. Four different systems of polymer composites were prepared: (1) montmorillonite clay/fertilizer, (2) montmorillonite clay/thermoplastic starch and fertilizer, (3) montmorillonite clay/fertilizer, thermoplastic starch and low-density polyethylene (LDPE) and also (4) montmorillonite clay/fertilizer, thermoplastic starch and polycaprolactone. It was confirmed the formation of nano structured materials by elemental analysis (CHN) and X-ray diffraction (XRD). The kinetics of nitrogen release was detected by enzymatic colorimetric analysis and spectroscopy in the ultraviolet/visible. The results showed that all materials evaluated were able to reduce the rate of release of nitrogen in the fertilizers. (author)

  12. Influence of predictive contamination to agricultural products due to dry and wet processes during an accidental release of radionuclides

    International Nuclear Information System (INIS)

    Hwang, Won Tae; Kim, Eun Han; Suh, Kyung Suk; Jeong, Hyo Joon; Han, Moon Hee; Lee, Chang Woo

    2003-01-01

    The influence of predictive contamination to agricultural products due to the wet processes as well as dry processes from radioactive air concentration during a nuclear emergency is comprehensively analyzed. The previous dynamic food chain model DYNACON considering Korean agricultural and environmental conditions, in which the initial input parameter was radionuclide concentrations on the ground, is improved so as to evaluate radioactive contamination to agricultural products from either radioactive air concentrations or radionuclide concentrations on the ground. As for the results, wet deposition is a more dominant mechanism than dry deposition in contamination on the ground. While, the contamination levels of agricultural products are strongly dependent on radionuclide and precipitation when the deposition of radionuclides occurs. It means that the contamination levels of agricultural products are determined from which is the more dominant process between deposition on the ground and interception to agricultural plants

  13. Natural analogue approach for estimating the health risks from release and migration of radionuclides from radioactive waste

    International Nuclear Information System (INIS)

    Gilbert, T.L.

    1983-01-01

    The health risks from radioactive waste may be expressed as a sum of products of transfer factors that characterize the causal chain of events between disposal of radionuclides in a waste field and the consequent health effects. Model estimates for the transfer factors are commonly obtained by modeling transport and other mechanisms in the subsystems that form the links in the causal chain. Natural estimates of some conversion factors for naturally occurring radionuclides can be obtained from data on the concentrations of naturally occurring radionuclides in soil, food, and the human body. These model and natural estimates can be used with scaling procedures to estimate the uncertainties and to obtain better estimates of the values. The scaling procedures take into account the differences in the source characteristics for radionuclides in a waste field of limited size and for radionuclides generally distributed in the natural environment. The ratios of the natural estimates to the model estimates for several transfer factors and several radionuclides belonging to the U-238 decay series have been determined. These ratios range from 1/8 to 4/1 for food-concentration/source-concentration transfer factors for the food pathways and from 1 to 77 for dose-rate/source-concentration transfer factors for the internal radiation dose pathways to various organs. 14 references

  14. Predicted radionuclide release from reactor-related unenclosed solid objects dumped in the Sea of Japan and the Pacific Ocean, east coast of Kamchatka

    International Nuclear Information System (INIS)

    Mount, M.E.; Lynn, N.M.; Warden, J.M.

    1996-06-01

    Between 1978 and 1991 reactor-related solid radioactive waste was dumped by the former Soviet Union as unenclosed objects in the Pacific Ocean, east coast of Kamchatka, and the Sea of Japan. This paper presented estimates for the current (1994) inventory of activation and corrosion products contained in the reactor-related unenclosed solid objects. In addition, simple models derived for prediction of radionuclide release from marine reactors dumped in the Kara Sea are applied to certain of the dumped objects to provide estimates of radionuclide release to the Pacific Ocean, east coast of Kamchatka, and Sea of Japan environments. For the Pacific Ocean, east coast of Kamchatka, total release rates start below 0.01 GBq yr -1 and over 1,000 years, fall to 100 Bq yr -1 . In the Sea of Japan, the total release rate starts just above 1 GBq yr - 1 , dropping off to a level less than 0.1 GBq yr -1 , extending past the year 4,000

  15. Overview study of LNG release prevention and control systems

    Energy Technology Data Exchange (ETDEWEB)

    Pelto, P.J.; Baker, E.G.; Holter, G.M.; Powers, T.B.

    1982-03-01

    The liquefied natural gas (LNG) industry employs a variety of release prevention and control techniques to reduce the likelihood and the consequences of accidental LNG releases. A study of the effectiveness of these release prevention and control systems is being performed. Reference descriptions for the basic types of LNG facilities were developed. Then an overview study was performed to identify areas that merit subsequent and more detailed analyses. The specific objectives were to characterize the LNG facilities of interest and their release prevention and control systems, identify possible weak links and research needs, and provide an analytical framework for subsequent detailed analyses. The LNG facilities analyzed include a reference export terminal, marine vessel, import terminal, peakshaving facility, truck tanker, and satellite facility. A reference description for these facilities, a preliminary hazards analysis (PHA), and a list of representative release scenarios are included. The reference facility descriptions outline basic process flows, plant layouts, and safety features. The PHA identifies the important release prevention operations. Representative release scenarios provide a format for discussing potential initiating events, effects of the release prevention and control systems, information needs, and potential design changes. These scenarios range from relatively frequent but low consequence releases to unlikely but large releases and are the principal basis for the next stage of analysis.

  16. Development and Optimization of controlled drug release ...

    African Journals Online (AJOL)

    The aim of this study is to develop and optimize an osmotically controlled drug delivery system of diclofenac sodium. Osmotically controlled oral drug delivery systems utilize osmotic pressure for controlled delivery of active drugs. Drug delivery from these systems, to a large extent, is independent of the physiological factors ...

  17. Transfer of radionuclides in soil-plant systems following aerosol simulation of accidental release: design and first results

    International Nuclear Information System (INIS)

    Rauret, G.; Real, J.

    1995-01-01

    The behaviour of 134 Cs, 110m Ag and 85 Sr was studied in different soil-plant systems, using two types of Mediterranean soil with contrasting properties (sandy and sandy-loam soils). The plant species used was lettuce (Lactuca sativa). Contamination was induced at different stages of plant growth, using a synthetic aerosol which simulated a distant contamination source. Characterisation of aerosol and soils, interception factors in the various growth stages, foliar and root uptake, leaching from leaves by irrigation and distribution and migration of radionuclides of soils were studied, in an attempt to understand the key factors involving radionuclide soil-to-plant transferance. (author)

  18. Transfer of radionuclides in soil-plant systems following aerosol simulation of accidental release: design and first results

    Energy Technology Data Exchange (ETDEWEB)

    Rauret, G. [Universitat de Barcelona (Spain). Dept. of Quimica Analitica; Vallejo, V.R. [Universitat de barcelona (Spain). Dept. of Biologia Vegetal; Cancio, D. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Madrid (Spain); Real, J. [CEA Centre d`Etudes de Fontenay-aux-Roses, 92 (France). Inst. de Protection et de Surete Nucleaire

    1995-12-31

    The behaviour of {sup 134}Cs, {sup 110m}Ag and {sup 85}Sr was studied in different soil-plant systems, using two types of Mediterranean soil with contrasting properties (sandy and sandy-loam soils). The plant species used was lettuce (Lactuca sativa). Contamination was induced at different stages of plant growth, using a synthetic aerosol which simulated a distant contamination source. Characterisation of aerosol and soils, interception factors in the various growth stages, foliar and root uptake, leaching from leaves by irrigation and distribution and migration of radionuclides of soils were studied, in an attempt to understand the key factors involving radionuclide soil-to-plant transferance. (author).

  19. Guide for radiological safety advisers of the disaster control service management for nuclear emergencies. In annex: Radiological fundamentals for decisions on actions for protection of the population against the consequences of accidental release of radionuclides. - Outline recommendations for disaster control actions in the vicinity of nuclear installations

    International Nuclear Information System (INIS)

    Seredynski, J.

    1989-01-01

    This Guide published as vol. 13 of the SSK publications is a revised version of the loose-leaf publication 'Compilation of criteria and decision aids for technical advisers for nuclear emergency control services'. The general arrangement of the material has been maintained as it proved to be useful, so that this issue as the previous one presents information on determining the source strength of the radioactive substances, their dispersion characteristics, and resulting radiation exposure on doses. Special attention has been paid to presenting helpful data for shortening as much as possible the calculation time required, as e.g. by pre-evaluation data presented in the form of graphs. Realistic dose assessments are made possible on the basis of the latest scientific knowledge, including the results of the German Risk. Assessment Study for Nuclear Power Plants, and the dose factors given by the Federal Health Office. Aids given for dose assessment are the following: Forms together with tables and graphs; nomograms; isometric representations of isopleths and isodose curves. In addition, information is given for evaluation of dose assessments and recommendations to be inferred for protective actions. (orig./HP) With 21 figs., 37 tabs [de

  20. 1{sup st} annual workshop proceedings of the collaborative project ''Fast/instant release of safety relevant radionuclides from spent nuclear fuel'' (7{sup th} EC FP CP FIRST-Nuclides)

    Energy Technology Data Exchange (ETDEWEB)

    Kienzler, Bernhard; Metz, Volker; Duro, Lara; Valls, Alba (eds.)

    2013-07-01

    place at the rim of the fuel pellets. The physico-chemical properties of the fuel are further complicated by additions of gadolinium oxide and/or chromium oxide, which is used for criticality control or to adjust the UO{sub 2} grain sizes for minimizing fission gas release (FGR). Moreover, the fission products of uranium cause expansion in the UO{sub 2} crystal structure leading to disturbances of the fuel matrix. The chemical stability of the fission products oxides in the UO{sub 2} matrix, can be classified into different groups: (i) the rare earth elements and Y, Zr, Ba and Sr, whose oxides form either solid solutions with UO{sub 2} or single phase precipitates; (ii) Mo, Cs and Rb, which are either oxidized or not, depending on the O/U ratio; and (iii) elements like Ru, with unstable oxides which form metallic precipitates within the UO{sub 2}. The CP is organized in six workpackages (WP): WP1, ''Samples and tools'' deals with the selection, characterization and preparation of the materials to be studied and the set-up of experimental and organisational tools. In this sense, one of the essential requirements of the project is that typical and sufficiently well characterized spent nuclear fuel is being used for the experiments and modelling studies. WP2 covers the ''Gas release and rim and grain boundary diffusion experiments'' and WP3 addresses ''Dissolution based release studies''. This includes determining the chemical form of released radionuclides, fission gases, {sup 135}Cs, {sup 129}I, {sup 14}C, {sup 79}Se, {sup 99}Tc and {sup 126}Sn. WP4 ''Modelling'' deals with modelling of release/retention processes of fission products in the spent fuel structure. Special attention is attributed to fission product migration along the grain boundaries, the effects of fractures in the pellets and of holes/fractures in the cladding. The modelling work within FIRST-Nuclides will help to clarify

  1. 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)

  2. A review of the role of colloids in the release and transport of radionuclides in the near and far field. Pt. 2

    International Nuclear Information System (INIS)

    Tipping, E.; Higgo, J.J.W.

    1992-01-01

    The role of colloids in the release/transport of radionuclides covers a range of scientific disciplines and there is a need for a comprehensive review that pulls together all the relevant research. A literature review has, therefore, been carried out and a bibliography prepared. Entries are in alphabetical (first author) order and abstracts are provided. This is part 2 of a three-part review. Part 1 reviews fundamental theory and DOE and NIREX funded work while Part 3 compares DOE and NIREX-funded work with the other published work and identifies gaps in the DOE and NIREX programmes. (Author)

  3. Scenarios for long-term release of radionuclides from a nuclear-waste repository in the Los Medanos region of New Mexico

    International Nuclear Information System (INIS)

    Bingham, F.W.; Barr, G.E.

    1979-05-01

    This report discusses hypothetical sequences of events that could conceivably release radionuclides from radioactive waste buried in the proposed WIPP repository. All the scenarios are described in terms specific to the WIPP site; they include only events whose occurrence is physically possible there. The report estimates the relative probabilities of the scenarios at times ranging from 1000 to 1 million years after the repository is sealed. Although none of the scenarios is judged likely, the report recommends several for detailed computer modeling and consequence analysis

  4. How controlled release technology can aid gene delivery.

    Science.gov (United States)

    Jo, Jun-Ichiro; Tabata, Yasuhiko

    2015-01-01

    Many types of gene delivery systems have been developed to enhance the level of gene expression. Controlled release technology is a feasible gene delivery system which enables genes to extend the expression duration by maintaining and releasing them at the injection site in a controlled manner. This technology can reduce the adverse effects by the bolus dose administration and avoid the repeated administration. Biodegradable biomaterials are useful as materials for the controlled release-based gene delivery technology and various biodegradable biomaterials have been developed. Controlled release-based gene delivery plays a critical role in a conventional gene therapy and genetic engineering. In the gene therapy, the therapeutic gene is released from biodegradable biomaterial matrices around the tissue to be treated. On the other hand, the intracellular controlled release of gene from the sub-micro-sized matrices is required for genetic engineering. Genetic engineering is feasible for cell transplantation as well as research of stem cells biology and medicine. DNA hydrogel containing a sequence of therapeutic gene and the exosome including the individual specific nucleic acids may become candidates for controlled release carriers. Technologies to deliver genes to cell aggregates will play an important role in the promotion of regenerative research and therapy.

  5. Behaviour of U-Series Radionuclides in an Estuary Affected by Acid Mine Drainage and Industrial Releases

    Energy Technology Data Exchange (ETDEWEB)

    Hierro, A.; Bolivar, J. P.; Vaca, F. [Department of Applied Physics, University of Huelva, Huelva (Spain)

    2013-07-15

    The estuary formed by the Tinto and Odiel rivers is an ecosystem of great interest because it is seriously affected by the acid mine drainage (AMD) produced by the high mining activity in the watersheds of these rivers, generating in their waters an extremely low pH (2.5- 3.5), and consequently high concentrations of heavy metals and natural radionuclides in dissolution. Secondly, in their estuary there is a large chemical industrial complex, and in particular two phosphoric acid production plants, which use a sedimentary phosphate rock from Morocco as raw material containing at approximately 1.5 Bq/g of U-series radionuclides, which produce annually about 2.5-3 millions of tonnes of a byproduct, called phosphogypsum (PG). PG contains high concentrations of some U-series radionuclides as {sup 226}Ra (650 Bq/kg), {sup 210}Pb-{sup 210}Po (600 Bq/kg) or {sup 230}Th (450 Bq/kg). Seventeen sampling stations along the end of these rivers and this estuary were selected to study the behaviour of U-series radionuclides in the recent surface sediments and its waters. The most relevant results show a non-conservative behaviour of Uisotopes, precipitating in the zone where large pH changes (3-5) are produced. This behaviour is different from the majority of typical estuaries where only salinity changes are produced, and therefore, a conservative behaviour of uranium is observed. (author)

  6. Antimicrobial beeswax coated polylactide films with silver control release capacity.

    Science.gov (United States)

    Martínez-Abad, Antonio; Lagarón, Jose Maria; Ocio, María Jose

    2014-03-17

    Although the application of silver based antimicrobial systems is a widespread technology, its implementation in areas such as food packaging is still challenging. The present paper describes the fabrication of poly(lactic acid) (PLA) coated with beeswax with controlled release properties for sustained antimicrobial performance. Release of silver ions from the polymers was monitored voltammetrically under various conditions (surface contact, immersion in various liquid media and at different pH values) throughout at least 7days. A higher release was noted with decreasing pH while surface release was much slower than the release when immersed in liquid medium. While uncoated films demonstrated a high burst release which in some instances implied surpassing some current migration restrictions (food), the addition of a beeswax layer allowed a sustained release of the antimicrobial compound. Increasing the thickness of the beeswax layer resulted in an increase in the water barrier properties of the films while reducing the relatively constant values of sustained release. Antimicrobial performance was correlated with the release of silver ions, indicating threshold concentrations for biocide action of films displayed a strong bactericidal effect against Salmonella enterica. The application of this functional barrier thus offers the possibility of tuning the release profiles of the films to suit a specific application and puts forth the possible suitability of these materials for food packaging or other migration sensitive applications. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Photoresponsive lipid-polymer hybrid nanoparticles for controlled doxorubicin release

    Science.gov (United States)

    Yao, Cuiping; Wu, Ming; Zhang, Cecheng; Lin, Xinyi; Wei, Zuwu; Zheng, Youshi; Zhang, Da; Zhang, Zhenxi; Liu, Xiaolong

    2017-06-01

    Currently, photoresponsive nanomaterials are particularly attractive due to their spatial and temporal controlled drug release abilities. In this work, we report a photoresponsive lipid-polymer hybrid nanoparticle for remote controlled delivery of anticancer drugs. This hybrid nanoparticle comprises three distinct functional components: (i) a poly(D,L-lactide-co-glycolide) (PLGA) core to encapsulate doxorubicin; (ii) a soybean lecithin monolayer at the interface of the core and shell to act as a molecular fence to prevent drug leakage; (iii) a photoresponsive polymeric shell with anti-biofouling properties to enhance nanoparticle stability, which could be detached from the nanoparticle to trigger the drug release via a decrease in the nanoparticle’s stability under light irradiation. In vitro results revealed that this core-shell nanoparticle had excellent light-controlled drug release behavior (76% release with light irradiation versus 10% release without light irradiation). The confocal microscopy and flow cytometry results also further demonstrated the light-controlled drug release behavior inside the cancer cells. Furthermore, a CCK8 assay demonstrated that light irradiation could significantly improve the efficiency of killing cancer cells. Meanwhile, whole-animal fluorescence imaging of a tumor-bearing mouse also confirmed that light irradiation could trigger drug release in vivo. Taken together, our data suggested that a hybrid nanoparticle could be a novel light controlled drug delivery system for cancer therapy.

  8. Stimuli-Responsive Materials for Controlled Release Applications

    KAUST Repository

    Li, Song

    2015-01-01

    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

  9. Dose rates as a function of time due to postulated radionuclide releases from the U.S. Yucca Mountain high-level radioactive waste repository

    International Nuclear Information System (INIS)

    Moeller, Dade W.; Sun, Lin-Shen C.; Cherry, Robert

    2008-01-01

    The Yucca Mountain repository, which is located in a remote area in the State of Nevada, is being constructed for the long-term care and disposal of spent nuclear fuel and vitrified high-level radioactive waste. In accordance with U.S. law, the U.S. Environmental Protection Agency (USEPA) promulgated Standards that limit the dose rates to members of the public due to the consumption of ground water, alone, and the consumption of ground water plus agricultural products irrigated with the contaminated ground water, and other exposures, such as those from external sources and the inhalation of airborne radioactive materials. As part of this exercise, the USEPA identified eight specific radionuclides to which their Standards are to apply. These are: 14 C, 99 Tc, 129 I, 226 Ra, 228 Ra, 237 Np, 239 Pu, and 241 Am. For purposes of the associated dose rate estimates, a range of conservative assumptions have been applied, all of which are designed to assure that the estimated dose rates are well above what might be expected under 'real-world' conditions. As a first step, it was assumed that: (1) at 10 4 year after repository closure, a fractional release of 10 -5 of the entire repository radionuclide inventory occurred; (2) the only prior reduction in the inventory was that due to radioactive decay; and (3) the sole path of exposure to neighboring population groups was through the consumption of 2 L d -1 of contaminated ground water. The accompanying analyses revealed that, of the eight radionuclides, only 226 Ra, 237 Np, and 239 Pu, will represent a significant source of dose at that time. To provide perspective and insights, the next step was to estimate the committed effective dose rates for all eight radionuclides based on an assumed fractional release each year of 10 -5 of the inventory from the time of repository closure up through the 10 6 year. For purposes of providing perspective, it was assumed that each dose rate estimate was independent, that is, no releases

  10. Control decisions for 3H, 14C, 85Kr, and 129I released from the commercial fuel cycle

    International Nuclear Information System (INIS)

    Thomas, T.R.; Brown, R.A.

    1985-01-01

    The effects of complete release of 3 H, 14 C, 85 Kr and 129 I from operating a 400-GWe fuel cycle for 100 years are shown. The postulated accrued health effects (HE) from 14 C and 129 I appear large; however, these numbers are insignificant when compared to the 176 billion cancer deaths that would occur from all causes in the 10,000-year reference period. The percent increase in global cancer deaths would be no greater than 5 x 10 -5 % for each of the radionuclides. Based on the 1980 inventory of each radionuclide in the environment, complete release for 100 years from a 400-GWe fuel cycle would not increase the 3 H or 14 C inventories, however, large increases in 85 Kr and 129 I inventories would occur. The effects, besides dose impacts, of large increases in inventory are unknown and serve only as warning flags that should be taken into consideration. Only 129 I releases from a fuel reprocessing plant would exceed the allowable maximum exposed individual dose limit and 85 Kr and 129 I would exceed the allowable release limit. The effects of controlled releases from commercial fuel reprocessing plants serving a 400-GWe fuel cycle for 100 years are also shown

  11. Release and transport of artificial radionuclides from nuclear weapons related activities in the Ob River, Siberia over the course of the nuclear age

    International Nuclear Information System (INIS)

    Sayles, F.L.; Kenna, T.C.; Livingston, H.D.

    1999-01-01

    Studies of sediment cores from lakes on the flood plain of the Ob River, Siberia have been used to develop a history of the release, transport, and deposition of artificial radionuclides related to the development and testing of nuclear weapons over the duration of the nuclear age (∼1950 to the present) in this major Arctic river system. The Ob is of particular importance in this regard as two of the former Soviet Union's major weapons production plants, Mayak and Tomsk-7, and the Semipalatinsk test site are located within the Ob drainage basin. Accidents and intentional releases of radionuclides at both plants have been substantial, raising the issue of transport throughout this extensive river system as well as delivery to the Arctic Ocean. Our studies have included determining sediment profiles of 239,240 Pu, 137 Cs, and the natural nuclide 210 Pb and its parent 226 Ra in a number of cores from the Ob delta, as well as analysis of 239 Pu, 240 Pu, and 237 Np. The latter provide sensitive measures of the presence of non-fallout materials derived from weapons production activities

  12. To the problem of control methods unification of natural and artificial radionuclide admission into environment

    International Nuclear Information System (INIS)

    Gedeonov, L.I.

    1981-01-01

    Radioactive substances (RAS) released into the environment during NPP operation form the fields of increased radiation level as compared with the natural background. Preservation of the environment from intolerable contamination requires deter-- mination of the effluent norm by concentration and quantity of RAS released to the environment for every source. The necessity of unification of the methods for radioactive nuclide control of the environment as well as means and conditions of this control are discussed [ru

  13. Release of natural radionuclides in the Czech Republic - from water treatment plants where water from underground water sources is treated

    International Nuclear Information System (INIS)

    Sinaglova, R.

    2014-01-01

    In this abstract author deals with the treatment of drinking water in the Czech Republic with removing of natural radionuclides as well as with treatment of filter cartridges. The advantage of these technologies is that flushing is not required so no wastewater occurs. Used ion exchangers with higher content of uranium are processed in the chemical treatment of uranium ores, managed by DIAMO, state enterprise. (authors)

  14. Imprecision of dose predictions for radionuclides released to the environment: an application of a Monte Carlo simulation technique

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, G; Hoffman, F O

    1980-01-01

    An evaluation of the imprecision in dose predictions for radionuclides has been performed using correct dose assessment models and knowledge of model parameter value uncertainties. The propagation of parameter uncertainties is demonstrated using a Monte Carlo technique for elemental iodine 131 transported via the pasture-cow-milk-child pathway. Results indicated that when site-specific information is unavailable, the imprecision inherent in the predictions for this pathway is potentially large. (3 graphs, 25 references, 5 tables)

  15. 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.

  16. Radionuclide generators

    International Nuclear Information System (INIS)

    Lambrecht, R.M.

    1983-01-01

    The status of radionuclide generators for chemical research and applications related to the life sciences and biomedical research are reviewed. Emphasis is placed upon convenient, efficient and rapid separation of short-lived daughter radionuclides in a chemical form suitable for use without further chemical manipulation. The focus is on the production of the parent, the radiochemistry associated with processing the parent and daughter, the selection and the characteristic separation methods, and yields. Quality control considerations are briefly noted. The scope of this review includes selected references to applications of radionuclide generators in radiopharmaceutical chemistry, and the life sciences, particularly in diagnostic and therapeutic medicine. The 99 Mo-sup(99m)Tc generator was excluded. 202 references are cited. (orig.)

  17. Controlled release of tocopherols from polymer blend films

    Science.gov (United States)

    Obinata, Noe

    Controlled release packaging has great potential to increase storage stability of foods by releasing active compounds into foods continuously over time. However, a major limitation in development of this technology is the inability to control the release and provide rates useful for long term storage of foods. Better understanding of the factors affecting active compound release is needed to overcome this limitation. The objective of this research was to investigate the relationship between polymer composition, polymer processing method, polymer morphology, and release properties of active compounds, and to provide proof of principle that compound release is controlled by film morphology. A natural antioxidant, tocopherol was used as a model active compound because it is natural, effective, heat stable, and soluble in most packaging polymers. Polymer blend films were produced from combination of linear low density polyethylene (LLDPE) and high density polyethylene (HDPE), polypropylene (PP), or polystyrene (PS) with 3000 ppm mixed tocopherols using conventional blending method and innovative blending method, smart blending with a novel mixer using chaotic advection. Film morphologies were visualized with scanning electron microscopy (SEM). Release of tocopherols into 95% ethanol as a food simulant was measured by UV/Visible spectrophotometry or HPLC, and diffusivity of tocopherols in the polymers was estimated from this data. Polymer composition (blend proportions) and processing methods have major effects on film morphology. Four different types of morphologies, dispersed, co-continuous, fiber, and multilayer structures were developed by either conventional extrusion or smart blending. With smart blending of fixed polymer compositions, different morphologies were progressively developed with fixed polymer composition as the number of rod rotations increased, providing a way to separate effects of polymer composition and morphology. The different morphologies

  18. Microchips and controlled-release drug reservoirs.

    Science.gov (United States)

    Staples, Mark

    2010-01-01

    This review summarizes and updates the development of implantable microchip-containing devices that control dosing from drug reservoirs integrated with the devices. As the expense and risk of new drug development continues to increase, technologies that make the best use of existing therapeutics may add significant value. Trends of future medical care that may require advanced drug delivery systems include individualized therapy and the capability to automate drug delivery. Implantable drug delivery devices that promise to address these anticipated needs have been constructed in a variety of ways using micro- and nanoelectromechanical systems (MEMS or NEMS)-based technology. These devices expand treatment options for addressing unmet medical needs related to dosing. Within the last few years, advances in several technologies (MEMS or NEMS fabrication, materials science, polymer chemistry, and data management) have converged to enable the construction of miniaturized implantable devices for controlled delivery of therapeutic agents from one or more reservoirs. Suboptimal performance of conventional dosing methods in terms of safety, efficacy, pain, or convenience can be improved with advanced delivery devices. Microchip-based implantable drug delivery devices allow localized delivery by direct placement of the device at the treatment site, delivery on demand (emergency administration, pulsatile, or adjustable continuous dosing), programmable dosing cycles, automated delivery of multiple drugs, and dosing in response to physiological and diagnostic feedback. In addition, innovative drug-medical device combinations may protect labile active ingredients within hermetically sealed reservoirs. Copyright (c) 2010 John Wiley & Sons, Inc.

  19. Controlled release of curcumin from poly(HEMA-MAPA) membrane.

    Science.gov (United States)

    Caka, Müşerref; Türkcan, Ceren; Aktaş Uygun, Deniz; Uygun, Murat; Akgöl, Sinan; Denizli, Adil

    2017-05-01

    In this work, poly(HEMA-MAPA) membranes were prepared by UV-polymerization technique. These membranes were characterized by SEM, FTIR, and swelling studies. Synthesized membranes had high porous structure. These membranes were used for controlled release of curcumin which is already used as folk remedy and used as drug for some certain diseases and cancers. Curcumin release was investigated for various pHs and temperatures. Optimum drug release yield was found to be as 70% at pH 7.4 and 37 °C within 2 h period. Time-depended release of curcumin was also investigated and its slow release from the membrane demonstrated within 48 h.

  20. 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.

  1. 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

  2. User guide programmer's reference. NUDOS: A computer programme for assessing the consequences of airborne releases of radionuclides

    International Nuclear Information System (INIS)

    Grupa, J.

    1996-10-01

    NUDOS is a computer program that can be used to evaluate the consequences of airborne releases of radioactive materials. The consequences evaluated are individual dose and associated radiological risk, collective dose and the contamination of land. The code is capable of dealing with both routine and accidental releases. For accidental releases both deterministic and probabilistic calculations can be performed and the impact and effectiveness of emergency actions can be evaluated. (orig.)

  3. Magnetic molecularly imprinted polymer for aspirin recognition and controlled release

    Energy Technology Data Exchange (ETDEWEB)

    Kan Xianwen; Geng Zhirong; Zhao Yao; Wang Zhilin; Zhu Junjie [State Key Laboratory of Coordination Chemistry, MOE Key Lab of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, 22 Hankou Road, Nanjing 210093 (China)], E-mail: wangzl@nju.edu.cn, E-mail: jjzhu@nju.edu.cn

    2009-04-22

    Core-shell structural magnetic molecularly imprinted polymers (magnetic MIPs) with combined properties of molecular recognition and controlled release were prepared and characterized. Magnetic MIPs were synthesized by the co-polymerization of methacrylic acid (MAA) and trimethylolpropane trimethacrylate (TRIM) around aspirin (ASP) at the surface of double-bond-functionalized Fe{sub 3}O{sub 4} nanoparticles in chloroform. The obtained spherical magnetic MIPs with diameters of about 500 nm had obvious superparamagnetism and could be separated quickly by an external magnetic field. Binding experiments were carried out to evaluate the properties of magnetic MIPs and magnetic non-molecularly imprinted polymers (magnetic NIPs). The results demonstrated that the magnetic MIPs had high adsorption capacity and selectivity to ASP. Moreover, release profiles and release rate of ASP from the ASP-loaded magnetic MIPs indicated that the magnetic MIPs also had potential applications in drug controlled release.

  4. Magnetic molecularly imprinted polymer for aspirin recognition and controlled release

    International Nuclear Information System (INIS)

    Kan Xianwen; Geng Zhirong; Zhao Yao; Wang Zhilin; Zhu Junjie

    2009-01-01

    Core-shell structural magnetic molecularly imprinted polymers (magnetic MIPs) with combined properties of molecular recognition and controlled release were prepared and characterized. Magnetic MIPs were synthesized by the co-polymerization of methacrylic acid (MAA) and trimethylolpropane trimethacrylate (TRIM) around aspirin (ASP) at the surface of double-bond-functionalized Fe 3 O 4 nanoparticles in chloroform. The obtained spherical magnetic MIPs with diameters of about 500 nm had obvious superparamagnetism and could be separated quickly by an external magnetic field. Binding experiments were carried out to evaluate the properties of magnetic MIPs and magnetic non-molecularly imprinted polymers (magnetic NIPs). The results demonstrated that the magnetic MIPs had high adsorption capacity and selectivity to ASP. Moreover, release profiles and release rate of ASP from the ASP-loaded magnetic MIPs indicated that the magnetic MIPs also had potential applications in drug controlled release.

  5. Design and characterization of controlled release tablet of metoprolol

    Directory of Open Access Journals (Sweden)

    Gautam Singhvi

    2012-01-01

    Full Text Available Metoprolol succinate is a selective beta-adrenergic receptor blocker useful in treatment of hypertension, angina and heart failure. The purpose of the present work was to design and evaluate controlled release matrix type tablet of Metoprolo succinate using HPMC K15M and Eudragit (RLPO and RSPO as a matrix forming agents. Effect of various polymer alone and combinations were studied in pH 1.2 buffer using USP type II paddle at 50 rpm. HPMC was used to form firm gel with Eudragit polymer. Formulation with Equal proportion (1:1 of Eudragit RSPO and RLPO showed optimum drug release t50 =7 hrs and t100 =16 hrs indicate optimum permeability for drug release from matrix. The drug release mechanism was predominantly found to be Non-Fickian diffusion controlled.

  6. Sintering of wax for controlling release from pellets

    OpenAIRE

    Singh, Reena; Poddar, S. S.; Chivate, Amit

    2007-01-01

    The purpose of the present study was to investigate incorporation of hydrophobic (ie, waxy) material into pellets using a thermal sintering technique and to evaluate the pellets in vitro for controlled release. Pellets prepared by extrusion-spheronization technology were formulated with a water-soluble drug, microcrystalline cellulose, and carnauba wax. Powdered carnauba wax (4%–20%) prepared by grinding or by emulsification was studied with an attempt to retard the drug release. The inclusio...

  7. Release kinetics of tocopherol and quercetin from binary antioxidant controlled-release packaging films.

    Science.gov (United States)

    Chen, Xi; Lee, Dong Sun; Zhu, Xuntao; Yam, Kit L

    2012-04-04

    This paper investigated the feasibility of manipulating packaging polymers with various degrees of hydrophobicity to release two antioxidants, tocopherol and quercetin, at rates suitable for long-term inhibition of lipid oxidation in food. For example, one antioxidant can be released at a fast rate to provide short-term/intermediate protection, whereas the other antioxidant can be released at a slower rate to provide intermediate/long-term protection of lipid oxidation. Controlled-release packaging films containing tocopherol and quercetin were produced using ethylene vinyl alcohol (EVOH), ethylene vinyl acetate (EVA), low-density polyethylene (LDPE), and polypropylene (PP) polymers; the release of these antioxidants to 95% ethanol (a fatty food simulant) was measured using UV-vis spectrophotometry, and Fickian diffusion models with appropriate initial and boundary conditions were used to fit the data. For films containing only quercetin, the results show that the release of quercetin was much faster but lasted for a much shorter time for hydrophilic polymers (EVOH and EVA) than for hydrophobic polymers (LDPE and PP). For binary antioxidant films containing tocopherol and quercetin, the results show that tocopherol released more rapidly but for a shorter period of time than quercetin in LDPE and EVOH films, and the difference is more pronounced for LDPE films than EVOH films. The results also show the presence of tocopherol can accelerate the release of quercetin. Although none of the films produced is acceptable for long-term lipid oxidation inhibition, the study provides encouraging results suggesting that acceptable films may be produced in the future using polymer blend films.

  8. FERLENT - a controlled release fertilizer produced from a polymer material

    International Nuclear Information System (INIS)

    Gonzalez, Mayra; Arces, Milagros; Cuesta, Ernesto; Corredera, Pilar; Sardina, Carmen; Rieumont, Jacques; Quintana, Patricia; Bartolo, Pascual; Guenther, Bluma

    2011-01-01

    The possibility to use release controlled fertilizers in the agriculture of the tropical countries is more important than in the agriculture of the countries of the template regions. In this context, this work purpose the development of a new Fertilizer of Controlled Release named FERLENT, which was obtained starting from a polymeric material, under controlled conditions which allowed to corroborate the adjustment of the synthesis parameters under the modulate of nutrients liberation. It was characterized by, Scanning Microscopy Electron (SEM), Thermogravimetric analysis (TGA), Nuclear Magnetic Resonance (NMR) and infrared spectroscopy (FTIR). (author)

  9. Sol-gel encapsulation for controlled drug release and biosensing

    Science.gov (United States)

    Fang, Jonathan

    The main focus of this dissertation is to investigate the use of sol-gel encapsulation of biomolecules for controlled drug release and biosensing. Controlled drug release has advantages over conventional therapies in that it maintains a constant, therapeutic drug level in the body for prolonged periods of time. The anti-hypertensive drug Captopril was encapsulated in sol-gel materials of various forms, such as silica xerogels and nanoparticles. The primary objective was to show that sol-gel silica materials are promising drug carriers for controlled release by releasing Captopril at a release rate that is within a therapeutic range. We were able to demonstrate desired release for over a week from Captopril-doped silica xerogels and overall release from Captopril-doped silica nanoparticles. As an aside, the antibiotic Vancomycin was also encapsulated in these porous silica nanoparticles and desired release was obtained for several days in-vitro. The second part of the dissertation focuses on immobilizing antibodies and proteins in sol-gel to detect various analytes, such as hormones and amino acids. Sol-gel competitive immunoassays on antibody-doped silica xerogels were used for hormone detection. Calibration for insulin and C-peptide in standard solutions was obtained in the nM range. In addition, NASA-Ames is also interested in developing a reagentless biosensor using bacterial periplasmic binding proteins (bPBPs) to detect specific biomarkers, such as amino acids and phosphate. These bPBPs were doubly labeled with two different fluorophores and encapsulated in silica xerogels. Ligand-binding experiments were performed on the bPBPs in solution and in sol-gel. Ligand-binding was monitored by fluorescence resonance energy transfer (FRET) between the two fluorophores on the bPBP. Titration data show that one bPBP has retained its ligand-binding properties in sol-gel.

  10. Sintering of wax for controlling release from pellets.

    Science.gov (United States)

    Singh, Reena; Poddar, S S; Chivate, Amit

    2007-09-14

    The purpose of the present study was to investigate incorporation of hydrophobic (ie, waxy) material into pellets using a thermal sintering technique and to evaluate the pellets in vitro for controlled release. Pellets prepared by extrusion-spheronization technology were formulated with a water-soluble drug, microcrystalline cellulose, and carnauba wax. Powdered carnauba wax (4%-20%) prepared by grinding or by emulsification was studied with an attempt to retard the drug release. The inclusion of ground or emulsified carnauba wax did not sustain the release of theophylline for more than 3 hours. Matrix pellets of theophylline prepared with various concentrations of carnauba wax were sintered thermally at various times and temperatures. In vitro drug release profiles indicated an increase in drug release retardation with increasing carnauba wax concentration. Pellets prepared with ground wax showed a higher standard deviation than did those prepared with emulsified wax. There was incomplete release at the end of 12 hours for pellets prepared with 20% ground or emulsified wax. The sintering temperature and duration were optimized to allow for a sustained release lasting at least 12 hours. The optimized temperature and duration were found to be 100 degrees C and 140 seconds, respectively. The sintered pellets had a higher hydrophobicity than did the unsintered pellets. Scanning electron micrographs indicated that the carnauba wax moved internally, thereby increasing the surface area of wax within the pellets.

  11. Estimates of external dose-rate conversion factors and internal dose conversion factors for selected radionuclides released from fusion facilities

    Energy Technology Data Exchange (ETDEWEB)

    Homma, Toshimitsu; Togawa, Orihiko [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-11-01

    This report provides a tabulation of both external dose-rate conversion factors and internal dose conversion factors using radioactive decay data in the updated Evaluated Nuclear Structure Data File (ENSDF) for selected 26 radionuclides and all their daughter radionuclides of potential importance in safety assessments of fusion facilities. The external dose-rate conversion factors for 21 target organs are tabulated for three exposure modes that are immersion in contaminated air, irradiation at a height of 1 m above a contaminated ground surface and immersion contaminated water. For internal exposure, committed dose equivalents, based on the methodology of ICRP Publication 30, in the same target organs per intake of unit activity are given for the inhalation and ingestion exposure pathways. The data presented here is intended to be generally used for safety assessments of fusion reactors. Comparisons of external effective dose-rate conversion factors and committed effective dose equivalents are made with the previous data from the independent data bases to provide quality assurance on our calculated results. There is generally good agreement among data from the independent data bases. The differences in the values of both effective dose-rate and dose conversion factors appeared are primarily due to differences in calculational methodology, the use of different radioactive decay data, and compilation errors. (author)

  12. MODELS SELECTED FOR CALCULATION OF DOSES, HEALTH EFFECTS AND ECONOMIC COSTS DUE TO ACCIDENTAL RADIONUCLIDE RELEASES FROM NUCLEAR POWER PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    Strenge, D L; Baker, D A; Droppo, J G; McPherson, R B; Napier, B A; Nieves, L A; Soldat, J K

    1980-05-01

    Models are described for use in site-specific environmental consequence analysis of nuclear reactor accidents of Classes 3 through 9. The models presented relate radioactivity released to resulting doses, health effects, and costs of remedial actions. Specific models are presented for the major exposure pathways of airborne releases, waterborne releases and direct irradiation from activity within the facility buildings, such as the containment. Time-dependent atmospheric dispersion parameters, crop production parameters and other variable parameters are used in the models. The environmental effects are analyzed for several accident start times during the year.

  13. Electrochemically controlled release of anticancer drug methotrexate using nanostructured polypyrrole modified with cetylpyridinium: Release kinetics investigation

    International Nuclear Information System (INIS)

    Alizadeh, Naader; Shamaeli, Ehsan

    2014-01-01

    A new simple strategy for direct electrochemical incorporation of chemotherapeutic methotrexate (MTX) into conductive polypyrrole (PPy) has been suggested for an electrochemically controlled loading and release system. Electropolymerization of MTX doped polypyrrole yielded poor quality with low efficiency of doping, but a well-doped, nanostructure and increased capacity of drug loading (24.5 mg g −1 ) has been obtained in the presence of cetylpyridinium (CP) as a modifier. When CP was preloaded onto PPy, the hydrophobic surface of the PPy serves as a backbone to which the hydrophobic chain of the CP can be attached. Electrostatic interaction between cationic CP with anionic MTX and aromatic interaction between pyridinium head of CP with pyrimidine and pyrazine rings of MTX increases drug doping. Then release kinetics were investigated at various applied potentials and temperatures. Kinetics analysis based on Avrami's equation showed that the drug release was controlled and accelerated by increasing temperature and negative potential and sustained by increasing positive potential. At open circuit condition, the release parameter (n) represented a diffusive mechanism and at applying electrochemical potentials, a first-order mode. Activation energy parameters (E a , ΔG ≠ , ΔH ≠ and ΔS ≠ ) and half-life time (t 1/2 ) of drug release are also analyzed as a function of applied potential. The nanostructured polymer films (PPy/CP/MTX) were characterized by several techniques: scanning electron microscopy, Furrier transforms Infrared, UV-vis spectroscopy. Overall, our results demonstrate that the PPy/CP/MTX films, combined with electrical stimulation, permit a programmable release of MTX by altering the interaction strength between the PPy/CP and MTX

  14. Method and apparatus for controlling accidental releases of tritium

    International Nuclear Information System (INIS)

    Galloway, T.R.

    1980-01-01

    An improvement in a tritium control system based on a catalytic oxidation reactor is provided wherein accidental releases of tritium into room air are controlled by flooding the catalytic oxidation reactor with hydrogen when the tritium concentration in the room air exceeds a specified limit. The sudden flooding with hydrogen heats the catalyst to a high temperature within seconds, thereby greatly increasing the catalytic oxidation rate of tritium to tritiated water vapor. Thus, the catalyst is heated only when needed. In addition to the heating effect, the hydrogen flow also swamps the tritium and further reduces the tritium release

  15. Method and apparatus for controlling accidental releases of tritium

    Science.gov (United States)

    Galloway, Terry R. [Berkeley, CA

    1980-04-01

    An improvement in a tritium control system based on a catalytic oxidation reactor wherein accidental releases of tritium into room air are controlled by flooding the catalytic oxidation reactor with hydrogen when the tritium concentration in the room air exceeds a specified limit. The sudden flooding with hydrogen heats the catalyst to a high temperature within seconds, thereby greatly increasing the catalytic oxidation rate of tritium to tritiated water vapor. Thus, the catalyst is heated only when needed. In addition to the heating effect, the hydrogen flow also swamps the tritium and further reduces the tritium release.

  16. User Guide ECOREA-RICE (version 1.0). Program for assessing the transfer of radionuclides released accidentally onto flooded rice-fields

    International Nuclear Information System (INIS)

    Keum, Dong Kwon; Lee, Han Soo; Choi, Hei Hu; Kang, Hee Seok; Lee, Chang Woo

    2004-05-01

    The computer code ECOREA-RICE is a dynamic compartment model that is specially designed for estimating the transfer of radionuclides deposited onto flooded rice-fields after an accidental release. The model consists of six independent compartments including rice-body, grain, surface water, root-zone soil, fixed soil and deep soil, and takes into account the transfer processes including radioactive decay, percolation, leaching, shoot-base absorption, root-uptake, weathering, translocation, fixation in soil by adsorption and desorption, and soil-mixing by plowing. The rate of the change of radioactivity in compartments is expressed by a set of the first order ordinary differential equations, which are solved by the fourth order Runge-Kutta algorithm. Input to the program includes the deposition date, transplanting date, ear emergence date, harvest date, soil data, the biomass data of rice-plant, and rate constants associated with transfer processes. Output includes the list of input data, the activity of radionuclides in compartment, the rate constant, and the transfer factor of rice-body and grain with time

  17. Rate setting and regulatory control of the radionuclides content in foodstuffs

    International Nuclear Information System (INIS)

    Shandala, N. K.; Savskin, M. N.; Petukhova, E. V.; Novikova, N. Y.; Titov, A. V.

    2004-01-01

    The concept of rate setting, standardisation and regulatory control of the radionuclides content in foodstuffs consists in the following: ? the normative standards concern to 90Sr and 137Cs as biologically significant radionuclides; ? the internal exposure dose from ingestion intake of radionuclides with food should not exceed meaning of 1 mSv a-1 which is the intervention exception level concerning trading foodstuffs; ? for few consumed foodstuffs (wild berries, mushrooms, teas) is established, that the dose caused by their consumption is outside of dose limits of 1 mSv a-1 and it should not exceed 1 % for each product; ? the nutrition structure of population including seven basic components of a diet (bread and grain products, dairy products, potatoes, vegetables, meat, fish, fruit and berries) is taken into account as a source of ingestion intake of the radionuclides; ? The conformity to the established standard is determined on a parameter ?f the summary contents of 90Sr and 137Cs in foodstuff. With the purpose of the operative control of an internal exposure of population the permissible levels of specific activity of 90Sr and 137Cs in more than 120 kinds of foodstuff were developed. These standards are obligatory in Russia for domestic and imported foodstuffs. So, permissible levels of specific activity of 90Sr and 137Cs in bread make, accordingly, 20 and 40 Bq kg-1; in milk - 25 and 100 Bq kg-1; in meat - 50 and 160 Bq kg-1; in potatoes and vegetables - 40 and 120 Bq kg-1. Monitoring of contamination of foodstuffs by 137Cs and 90Sr is one of the basic measures on maintenance of radiation safety of population in Russia. State system of sanitary-epidemiological control carries out constant supervision over the content of the radionuclides in food production. By the carried out researches was shown that true levels of the contents of 90Sr or 137Cs in the main foodstuffs in territory of Russia, except for the territories, injures of the radiation accidents, make

  18. The reactor accident at Chernobyl: A possibility to test colloid-controlled transport of radionuclides

    International Nuclear Information System (INIS)

    Von Gunten, H.R.; Waber, U.; Krahenbuhl, U.

    1987-01-01

    Radioactive fall-out from the damaged nuclear power plant at Chernobyl (USSR) has been measured between May 2 and May 20, 1986 in the River Glatt (Zurich, Switzerland) and in a shallow groundwater stream which is hydraulically connected to the river. Water infiltrating from the river into the groundwater was sampled at different distances and depths by means of a system of piezometer tubes which are part of an experimental installation for the investigation of groundwater quality and migration processes. The aquifer is a quarternary glaciofluvial deposit consisting of stones, gravel, sand, silt and clays. It is typical for large parts of alpine and peri-alpine regions and contains in Switzerlamd about 80% of the drinking water supplies. The radionuclides Tc-99m, Ru-103, I-131, Te-132, Cs-134 and Cs-137 were measured several times in the river water and in the groundwater using calibrated Ge(Li) gamma-ray spectrometers. Based on the present state of data evaluation the authors conclude that anionic species like iodides, ruthenates or tellurates are not or only slightly sorbed, whereas cesium is completely retained during infiltration from the river into the groundwater. Colloid (>0.05 μm) controlled migration of radionuclides in this heterogeneous glaciofluvial deposits is a transport mechanism of minor importance. However, with the present data it cannot be excluded completely

  19. Numerical modelling and parametric study of the atmospheric dispersion after radionuclide releases: the Chernobyl accident and the Algeciras incident. Comparison with observation data

    International Nuclear Information System (INIS)

    Minier, Y.; Mathieu, A.; Quelo, D.; Sportisse, B.; Isnard, O.; Krysta, M.; Bocquet, M.

    2006-01-01

    Full text: The attempts of modelling the release following upon the Chernobyl accident and the Algeciras incident are reported. Computing power and observation database are used for sensitivity and parametric studies. The meteorological mesoscale model MM5 is nudged with the ERA-40 reanalysis to simulate the meteorological conditions used by the dispersion model, POLAIR3D. In case of the Chernobyl accident the points of interest are many: the representativity of the meteorological simulations is evaluated using observations with a special focus on precipitation events. The radionuclide dispersion, the dry deposition and scavenging simulated by POLAIR3D are compared with European measurements of activities and depositions. Results of the sensitivity studies are done to evaluate the impact of the deposition parameterizations and source-term characteristics (height of release, quantities). The time dynamic of the contaminated cloud is also investigated with regard to the arrival time on different countries. Similarly, for the Algeciras release, sensitivity to the meteorological fields, source term and depletion processes are analyzed. For the available activity concentrations in the air, data-model comparisons are performed. (author)

  20. Predicted radionuclide release from marine reactors dumped in the Kara Sea. Report of the source term working group of the international arctic seas assessment project (IASAP)

    International Nuclear Information System (INIS)

    1997-04-01

    The present report summarizes the work carried out by the Source Term Working Group of IASAP during 1994-1996. The report is based on the studies concerning the initial and current radionuclide inventories, operational history and construction of the reactors carried out by Y. Sivintsev of the Russian Research Center ''Kurchatov Institute'', Moscow and E. Yefimov of the Institute of Physics and Power Engineering, Obninsk, Russian Federation. The working group convened five times and evaluated the results of the studies and developed models for prediction of potential releases to the environment. The calculations were carried out at the Royal Naval College, Greenwich, UK, by N. Lynn, J. Warden and S. Timms and at the Lawrence Livermore National Laboratory, California, USA, by M. Mount. 31 refs, 36 figs, 18 tabs

  1. Recommendations to the Technical Steering Panel regarding approach for estimating individual radiation doses resulting from releases of radionuclides to the Columbia River

    International Nuclear Information System (INIS)

    Napier, B.A.; Brothers, A.J.

    1992-07-01

    At the direction of the Technical Steering Panel (TSP) of the Hanford Environmental Dose Reconstruction (HEDR) Project, Battelle staff have reviewed and analyzed available data regarding possible historical radiation doses to individuals resulting from radionuclide releases to the Columbia River. The objective of this review was to recommend to the TSP the spatial and temporal scope and level of effort on Columbia River work to most effectively extend work performed in Phase I of the project (PNL 1991a, PNL 1991b) to meet the project objectives. A number of options were analyzed. Four stretches of the Columbia River and adjacent Pacific coastal waters were defined and investigated for four time periods. Radiation doses arising from ten potentially major exposure pathways were evaluated for each of the time/location combinations, and several alternative methods were defined for estimating the doses from each pathway. Preliminary cost estimates were also developed for implementing dose estimation activities for each of the possible combinations

  2. Controlled release of biofunctional substances by radiation-induced polymerization

    International Nuclear Information System (INIS)

    Yoshida, M.; Kumakura, M.; Kaetsu, I.

    1978-01-01

    The controlled release of potassium chloride from flat circular matrices made by radiation-induced polymerization of a glass-forming monomer at low temperatures has been studied. The water-particle phase content formed in a poly(diethylene glycol dimethacrylate) matrix was controlled by the addition of polyethylene glycol 600. The dispersed water-particle phase content in the matrix was estimated directly and by scanning electron microscopic observations. The release of potassium chloride from the matrix increased linearly with the square root of time. The water content of the matrix had an important effect on the release rate which increases roughly in proportion to water content. This effect can be attributed to the apparent increase of the rate of drug diffusion. (author)

  3. Thermosensitive liposomes entrapping iron oxide nanoparticles for controllable drug release

    International Nuclear Information System (INIS)

    Tai, L-A; Wang, Y-C; Wang, Y-J; Yang, C-S; Tsai, P-J; Lo, L-W

    2009-01-01

    Iron oxide nanoparticles can serve as a heating source upon alternative magnetic field (AMF) exposure. Iron oxide nanoparticles can be mixed with thermosensitive nanovehicles for hyperthermia-induced drug release, yet such a design and mechanism may not be suitable for controllable drug release applications in which the tissues are susceptible to environmental temperature change such as brain tissue. In the present study, iron oxide nanoparticles were entrapped inside of thermosensitive liposomes for AMF-induced drug release while the environmental temperature was maintained at a constant level. Carboxyfluorescein was co-entrapped with the iron oxide nanoparticles in the liposomes as a model compound for monitoring drug release and environmental temperature was maintained with a water circulator jacket. These experiments have been successfully performed in solution, in phantom and in anesthetized animals. Furthermore, the thermosensitive liposomes were administered into rat forearm skeletal muscle, and the release of carboxylfluorescein triggered by the external alternative magnetic field was monitored by an implanted microdialysis perfusion probe with an on-line laser-induced fluorescence detector. In the future such a device could be applied to simultaneous magnetic resonance imaging and non-invasive drug release in temperature-sensitive applications.

  4. CONTROLLED RELEASE, BLIND TEST OF DNAPL REMEDIATION BY ETHANOL FLUSHING

    Science.gov (United States)

    A dense nonaqueous phase liquid (DNAPL) source zone was established within a sheet-pileisolated cell through a controlled release of perchloroethylene (PCE) to evaluate DNAPLremediation by in-situ cosolvent flushing. Ethanol was used as the cosolvent, and the main remedia...

  5. Rectal absorption of morphine from controlled release suppositories

    NARCIS (Netherlands)

    Moolenaar, Frits; Meyler, Pim; Frijlink, Erik; Jauw, Tjoe Hang; Visser, Jan; Proost, Johannes

    1995-01-01

    The absorption profiles and bioavailability of morphine in human volunteers (n = 13) were described after oral administration of MS Contin tablets and rectal administration of a newly developed controlled release suppository. By manipulating the viscosity of fatty suppository base an entirely

  6. Controlled antiseptic release by alginate polymer films and beads.

    Science.gov (United States)

    Liakos, Ioannis; Rizzello, Loris; Bayer, Ilker S; Pompa, Pier Paolo; Cingolani, Roberto; Athanassiou, Athanassia

    2013-01-30

    Biodegradable polymeric materials based on blending aqueous dispersions of natural polymer sodium alginate (NaAlg) and povidone iodine (PVPI) complex, which allow controlled antiseptic release, are presented. The developed materials are either free standing NaAlg films or Ca(2+)-cross-linked alginate beads, which properly combined with PVPI demonstrate antibacterial and antifungal activity, suitable for therapeutic applications, such as wound dressing. Glycerol was used as the plasticizing agent. Film morphology was studied by optical and atomic force microscopy. It was found that PVPI complex forms well dispersed circular micro-domains within the NaAlg matrix. The beads were fabricated by drop-wise immersion of NaAlg/PVPI/glycerol solutions into aqueous calcium chloride solutions to form calcium alginate beads encapsulating PVPI solution (CaAlg/PVPI). Controlled release of PVPI was possible when the composite films and beads were brought into direct contact with water or with moist media. Bactericidal and fungicidal properties of the materials were tested against Escherichia coli bacteria and Candida albicans fungi. The results indicated very efficient antibacterial and antifungal activity within 48 h. Controlled release of PVPI into open wounds is highly desired in clinical applications to avoid toxic doses of iodine absorption by the wound. A wide variety of applications are envisioned such as external and internal wound dressings with controlled antiseptic release, hygienic and protective packaging films for medical devices, and polymer beads as water disinfectants. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Improvement of waste release control in French NPP

    International Nuclear Information System (INIS)

    Samson, T.; Lucquin, E.; Dupin, M.; Florence, D.; Grisot, M.

    2002-01-01

    The new waste release control in French NPP is more restrictive than the old one and needs heavy investment to bring plants to compliance with it. The great evolutions are a chemical follow up on more chemicals with a higher measurement frequency and with lower maximum concentrations and a specific measurement of carbon 14. Regarding radioactive releases, a new counting has been settled and activity of carbon 14 release is now measured and no longer calculated. The evolution of the French regulation leads to develop specific procedures and analytical techniques in chemistry and in radiochemistry (UV spectrometric methods, carbon 14 measurements,..) EDF NPP operators have launched a voluntarist process to reduce their releases since the beginning and before the evolution of the regulation. EDF priorities in terms of environment care lead henceforth to implement a global optimisation of the impact for a better control of releases. The new regulation will help EDF to reach its goals because it covers all the aspects in one administrative document: it is seen as a real simplification and a clarification towards public. In addition, this new regulation fits in with international practices which will allow an easier comparison of results between EDF and foreign NPP. These big environmental concerns lead EDF to create a national dedicated laboratory (LAMEN) in charge of developing specific measurement procedures to be implemented either by NPP or by sub-contractor laboratories. (authors)

  8. Controlled release of ethylene via polymeric films for food packaging

    Science.gov (United States)

    Pisano, Roberto; Bazzano, Marco; Capozzi, Luigi Carlo; Ferri, Ada; Sangermano, Marco

    2015-12-01

    In modern fruit supply chain a common method to trigger ripening is to keep fruits inside special chambers and initiate the ripening process through administration of ethylene. Ethylene is usually administered through cylinders with inadequate control of its final concentration in the chamber. The aim of this study is the development of a new technology to accurately regulate ethylene concentration in the atmosphere where fruits are preserved: a polymeric film, containing an inclusion complex of α-cyclodextrin with ethylene, was developed. The complex was prepared by molecular encapsulation which allows the entrapment of ethylene into the cavity of α-cyclodextrin. After encapsulation, ethylene can be gradually released from the inclusion complex and its release rate can be regulated by temperature and humidity. The inclusion complex was dispersed into a thin polymeric film produced by UV-curing. This method was used because is solvent-free and involves low operating temperature; both conditions are necessary to prevent rapid release of ethylene from the film. The polymeric films were characterized with respect to thermal behaviour, crystalline structure and kinetics of ethylene release, showing that can effectively control the release of ethylene within confined volume.

  9. Improvement of waste release control in French NPP

    Energy Technology Data Exchange (ETDEWEB)

    Samson, T.; Lucquin, E.; Dupin, M. [EDF/GDL (France); Florence, D. [EDF/GENV (France); Grisot, M. [EDF/CNPE Saint Laurent (France)

    2002-07-01

    The new waste release control in French NPP is more restrictive than the old one and needs heavy investment to bring plants to compliance with it. The great evolutions are a chemical follow up on more chemicals with a higher measurement frequency and with lower maximum concentrations and a specific measurement of carbon 14. Regarding radioactive releases, a new counting has been settled and activity of carbon 14 release is now measured and no longer calculated. The evolution of the French regulation leads to develop specific procedures and analytical techniques in chemistry and in radiochemistry (UV spectrometric methods, carbon 14 measurements,..) EDF NPP operators have launched a voluntarist process to reduce their releases since the beginning and before the evolution of the regulation. EDF priorities in terms of environment care lead henceforth to implement a global optimisation of the impact for a better control of releases. The new regulation will help EDF to reach its goals because it covers all the aspects in one administrative document: it is seen as a real simplification and a clarification towards public. In addition, this new regulation fits in with international practices which will allow an easier comparison of results between EDF and foreign NPP. These big environmental concerns lead EDF to create a national dedicated laboratory (LAMEN) in charge of developing specific measurement procedures to be implemented either by NPP or by sub-contractor laboratories. (authors)

  10. Methods and data for HTGR fuel performance and radionuclide release modeling during normal operation and accidents for safety analysis

    International Nuclear Information System (INIS)

    Verfondern, K.; Martin, R.C.; Moormann, R.

    1993-01-01

    The previous status report released in 1987 on reference data and calculation models for fission product transport in High-Temperature, Gas-Cooled Reactor (HTGR) safety analyses has been updated to reflect the current state of knowledge in the German HTGR program. The content of the status report has been expanded to include information from other national programs in HTGRs to provide comparative information on methods of analysis and the underlying database for fuel performance and fission product transport. The release and transport of fission products during normal operating conditions and during the accident scenarios of core heatup, water and air ingress, and depressurization are discussed. (orig.) [de

  11. Guide for radiological safety advisers for nuclear emergency control services. In the annex: radiological fundamentals and data in support of decisions about action for protection of the population from the effects of radionuclides released in an accident; safety guides for emergency preparedness and protection of the close-in area around nuclear installations. 2. rev. ed.

    International Nuclear Information System (INIS)

    Grunst, M.

    1995-01-01

    The publication of this second edition offered the possibility to update the material along with recent developments, as for instance the conclusion of the German Risk Study for Nuclear Power Plants, Phase B, or the coming into effect of the General Administrative Order relating to paragraph 45 Radiation Protection Ordinance (Derivation of radiation doses emanating from radioactive effluents from nuclear installations), or EC Directives stipulating maximum permissible limits of radioactivity in food and feed. The second edition is further extended by a new chapter on standard measuring strategies for ambient radioactivity monitoring after nuclear incidents or accidents, relating to the tasks to be performed by the radiolical safety adviser on site. Many tables and illustrations have been changed in the course of the revision of the first edition, as e.g. those showing the calculation of the gamma submersion dose, or atmospheric dispersion of emissions released at low altitudes. Tables have been added showing reference values for measures to be taken in case of skin contamination, classified according to urgency levels ( urgent, necessary, to be considered), modified by a lowering factor of 10. This is to ensure that also in case of emergencies creating a bottleneck in the emergency decontamination departments, decontamination will be considered down to values below 400 Bq/cm 2 . An annex lists an excerpt from ICRP Publication 60 (1990), showing the new mortality probability coefficients per Sv of dose, and the new tissue weighting factors. (orig.) [de

  12. 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

  13. The present status of rare gas release control

    International Nuclear Information System (INIS)

    Yamamoto, Hiroshi

    1974-01-01

    Of the rare gases Ar, Kr and Xe released from nuclear facilities, the problem of release control can be confined to 41 Ar, 85 Kr and 133 Xe. The cases of the latter two are described, as 41 Ar is not much significant. 133 Xe, having relatively short half-life, can be dealt sufficiently by holding-up in case of light water reactors. 85 Kr of long half-life must be removed : the methods are low temperature adsorption, liquefaction distillation, absorption and diaphragm method. As for future problem, there is disposal of concentrated rare gas. (Mori, K.)

  14. Metabolic control of vesicular glutamate transport and release.

    Science.gov (United States)

    Juge, Narinobu; Gray, John A; Omote, Hiroshi; Miyaji, Takaaki; Inoue, Tsuyoshi; Hara, Chiaki; Uneyama, Hisayuki; Edwards, Robert H; Nicoll, Roger A; Moriyama, Yoshinori

    2010-10-06

    Fasting has been used to control epilepsy since antiquity, but the mechanism of coupling between metabolic state and excitatory neurotransmission remains unknown. Previous work has shown that the vesicular glutamate transporters (VGLUTs) required for exocytotic release of glutamate undergo an unusual form of regulation by Cl(-). Using functional reconstitution of the purified VGLUTs into proteoliposomes, we now show that Cl(-) acts as an allosteric activator, and the ketone bodies that increase with fasting inhibit glutamate release by competing with Cl(-) at the site of allosteric regulation. Consistent with these observations, acetoacetate reduced quantal size at hippocampal synapses and suppresses glutamate release and seizures evoked with 4-aminopyridine in the brain. The results indicate an unsuspected link between metabolic state and excitatory neurotransmission through anion-dependent regulation of VGLUT activity. Copyright © 2010 Elsevier Inc. All rights reserved.

  15. Evaluation of olibanum and its resin as rate controlling matrix for controlled release of diclofenac

    OpenAIRE

    Chowdary KPR; Mohapatra P; Murali Krishna M

    2006-01-01

    Olibanum and its resin and carbohydrate fractions were evaluated as rate controlling matrix materials in tablets for controlled release of diclofenac. Diclofenac matrix tablets were formulated employing olibanum and its resin and carbohydrate fractions in different concentrations and the tablets were evaluated for various tablet characters including drug release kinetics and mechanism. Olibanum and its resin component exhibited excellent retarding effect on drug release from the matrix tablet...

  16. Hybrid nanostructured drug carrier with tunable and controlled drug release

    International Nuclear Information System (INIS)

    Depan, D.; Misra, R.D.K.

    2012-01-01

    We describe here a transformative approach to synthesize a hybrid nanostructured drug carrier that exhibits the characteristics of controlled drug release. The synthesis of the nanohybrid architecture involved two steps. The first step involved direct crystallization of biocompatible copolymer along the long axis of the carbon nanotubes (CNTs), followed by the second step of attachment of drug molecule to the polymer via hydrogen bonding. The extraordinary inorganic–organic hybrid architecture exhibited high drug loading ability and is physically stable even under extreme conditions of acidic media and ultrasonic irradiation. The temperature and pH sensitive characteristics of the hybrid drug carrier and high drug loading ability merit its consideration as a promising carrier and utilization of the fundamental aspects used for synthesis of other promising drug carriers. The higher drug release response during the application of ultrasonic frequency is ascribed to a cavitation-type process in which the acoustic bubbles nucleate and collapse releasing the drug. Furthermore, the study underscores the potential of uniquely combining CNTs and biopolymers for drug delivery. - Graphical abstract: Block-copolymer crystallized on carbon nanotubes (CNTs). Nanohybrid drug carrier synthesized by attaching doxorubicin (DOX) to polymer crystallized CNTs. Crystallized polymer on CNTs provide mechanical stability. Triggered release of DOX. Highlights: ► The novel synthesis of a hybrid nanostructured drug carrier is described. ► The drug carrier exhibits high drug loading ability and is physically stable. ► The high drug release is ascribed to a cavitation-type process.

  17. Highly Efficient Thermoresponsive Nanocomposite for Controlled Release Applications

    KAUST Repository

    Yassine, Omar

    2016-06-23

    Highly efficient magnetic release from nanocomposite microparticles is shown, which are made of Poly (N-isopropylacrylamide) hydrogel with embedded iron nanowires. A simple microfluidic technique was adopted to fabricate the microparticles with a high control of the nanowire concentration and in a relatively short time compared to chemical synthesis methods. The thermoresponsive microparticles were used for the remotely triggered release of Rhodamine (B). With a magnetic field of only 1 mT and 20 kHz a drug release of 6.5% and 70% was achieved in the continuous and pulsatile modes, respectively. Those release values are similar to the ones commonly obtained using superparamagnetic beads but accomplished with a magnetic field of five orders of magnitude lower power. The high efficiency is a result of the high remanent magnetization of the nanowires, which produce a large torque when exposed to a magnetic field. This causes the nanowires to vibrate, resulting in friction losses and heating. For comparison, microparticles with superparamagnetic beads were also fabricated and tested; while those worked at 73 mT and 600 kHz, no release was observed at the low field conditions. Cytotoxicity assays showed similar and high cell viability for microparticles with nanowires and beads.

  18. Highly Efficient Thermoresponsive Nanocomposite for Controlled Release Applications

    KAUST Repository

    Yassine, Omar; Zaher, Amir; Li, Erqiang; Alfadhel, Ahmed; Perez, Jose E.; Kavaldzhiev, Mincho; Contreras, Maria F.; Thoroddsen, Sigurdur T; Khashab, Niveen M.; Kosel, Jü rgen

    2016-01-01

    Highly efficient magnetic release from nanocomposite microparticles is shown, which are made of Poly (N-isopropylacrylamide) hydrogel with embedded iron nanowires. A simple microfluidic technique was adopted to fabricate the microparticles with a high control of the nanowire concentration and in a relatively short time compared to chemical synthesis methods. The thermoresponsive microparticles were used for the remotely triggered release of Rhodamine (B). With a magnetic field of only 1 mT and 20 kHz a drug release of 6.5% and 70% was achieved in the continuous and pulsatile modes, respectively. Those release values are similar to the ones commonly obtained using superparamagnetic beads but accomplished with a magnetic field of five orders of magnitude lower power. The high efficiency is a result of the high remanent magnetization of the nanowires, which produce a large torque when exposed to a magnetic field. This causes the nanowires to vibrate, resulting in friction losses and heating. For comparison, microparticles with superparamagnetic beads were also fabricated and tested; while those worked at 73 mT and 600 kHz, no release was observed at the low field conditions. Cytotoxicity assays showed similar and high cell viability for microparticles with nanowires and beads.

  19. Microbial control on decomposition of radionuclides-containing oily waste in soil

    Science.gov (United States)

    Selivanovskaya, Svetlana; Galitskaya, Polina

    2014-05-01

    The oily wastes are formed annually during extraction, refinement, and transportation of the oil and may cause pollution of the environment. These wastes contain different concentrations of waste oil (40-60%), waste water (30-90%), and mineral particles (5-40%). Some oily wastes also contain naturally occurring radionuclides which were incorporated by water that was pumped up with the oil. For assessment of the hazard level of waste treated soil, not only measurements of contaminants content are needed, because bioavailability of oily components varies with hydrocarbon type, and soil properties. As far as namely microbial communities control the decomposition of organic contaminants, biological indicators have become increasingly important in hazard assessment and the efficiency of remediation process. In this study the decomposition of radionuclides-containing oily waste by soil microbial communities were estimated. Waste samples collected at the Tikchonovskii petroleum production yard (Tatarstan, Russia) were mixed with Haplic greyzem soil at ratio 1:4 and incubated for 120 days. During incubation period, the total hydrocarbon content of the soil mixed with the waste reduced from 156 ± 48 g kg-1 to 54 ± 8 g kg-1 of soil. The concentrations of 226Ra and 232Th were found to be 643 ± 127, 254 ± 56 Bq kg-1 and not changed significantly during incubation. Waste application led to a soil microbial biomass carbon decrease in comparison to control (1.9 times after 1 day and 1.3 times after 120 days of incubation). Microbial respiration increased in the first month of incubation (up to 120% and 160% of control after 1 and 30 days, correspondingly) and decreased to the end of incubation period (74% of control after 120 days). Structure of bacterial community in soil and soil/waste mixture was estimated after 120 days of incubation using SSCP method. The band number decreased in contaminated soil in comparison to untreated soil. Besides, several new dominant DNA

  20. Controlled release systems containing solid dispersions: strategies and mechanisms.

    Science.gov (United States)

    Tran, Phuong Ha-Lien; Tran, Thao Truong-Dinh; Park, Jun Bom; Lee, Beom-Jin

    2011-10-01

    In addition to a number of highly soluble drugs, most new chemical entities under development are poorly water-soluble drugs generally characterized by an insufficient dissolution rate and a small absorption window, leading to the low bioavailability. Controlled-release (CR) formulations have several potential advantages over conventional dosage forms, such as providing a uniform and prolonged therapeutic effect to improve patient compliance, reducing the frequency of dosing, minimizing the number of side effects, and reducing the strength of the required dose while increasing the effectiveness of the drug. Solid dispersions (SD) can be used to enhance the dissolution rate of poorly water-soluble drugs and to sustain the drug release by choosing an appropriate carrier. Thus, a CR-SD comprises both functions of SD and CR for poorly water-soluble drugs. Such CR dosage forms containing SD provide an immediately available dose for an immediate action followed by a gradual and continuous release of subsequent doses to maintain the plasma concentration of poorly water-soluble drugs over an extended period of time. This review aims to summarize all currently known aspects of controlled release systems containing solid dispersions, focusing on the preparation methods, mechanisms of action and characterization of physicochemical properties of the system.

  1. Controlled release of agrochemicals intercalated into montmorillonite interlayer space.

    Science.gov (United States)

    Wanyika, Harrison

    2014-01-01

    Periodic application of agrochemicals has led to high cost of production and serious environmental pollution. In this study, the ability of montmorillonite (MMT) clay to act as a controlled release carrier for model agrochemical molecules has been investigated. Urea was loaded into MMT by a simple immersion technique while loading of metalaxyl was achieved by a rotary evaporation method. The successful incorporation of the agrochemicals into the interlayer space of MMT was confirmed by several techniques, such as, significant expansion of the interlayer space, reduction of Barrett-Joyner-Halenda (BJH) pore volumes and Brunauer-Emmett-Teller (BET) surface areas, and appearance of urea and metalaxyl characteristic bands on the Fourier-transform infrared spectra of the urea loaded montmorillonite (UMMT) and metalaxyl loaded montmorillonite (RMMT) complexes. Controlled release of the trapped molecules from the matrix was done in water and in the soil. The results reveal slow and sustained release behaviour for UMMT for a period of 10 days in soil. For a period of 30 days, MMT delayed the release of metalaxyl in soil by more than 6 times. It is evident that MMT could be used to improve the efficiency of urea and metalaxyl delivery in the soil.

  2. The use of laboratory adsorption data and models to predict radionuclide releases from a geological repository: A brief history

    International Nuclear Information System (INIS)

    Langmuir, D.

    1997-01-01

    Radionuclide (RN) adsorption has long been recognized as important to assure the isolation of nuclear wastes in a geological repository. Laboratory measured RN adsorption data have generally been expressed as distribution coefficient (K d ) values or adsorption isotherms. The surface complexation (SC) adsorption models were introduced in the late 1970''s. The best known of these models incorporate electrical double layer (EDL) theory. Their use requires that the water chemistry and surface properties of adsorbing rocks and minerals be fully characterized. Because the SC models are relatively mechanistic, they may allow extrapolation of adsorption results to repository conditions that lie outside the limited experimental range used to parameterize a given model. Turner has shown that the diffuse layer model (the simplest SC model) fits a wide range of RN adsorption data as well as the more complex models. Others have suggested ways to generalize and estimate SC model parameters for a variety of minerals, rocks and engineered materials. Degueldre and Werlni and Degueldre et al. have proposed a simplified SC model for RN adsorption that avoids EDL theory, in which the adsorption of RN species is estimated from linear free energy relationships. It is appropriate to ask how accurately RN adsorption behavior must be known or understood for total system performance analysis (TSPA). In most geological settings now being considered for repository development globally, it may suffice to select bounding K d values for the different rock types. Use of the SC models to describe RN adsorption can provide one with increased confidence that minimum K d ''s and the distribution of K d values the author might propose for TSPA are in fact conservative. 68 refs., 5 figs., 1 tab

  3. Radionuclides in an arctic terrestrial ecosystem affected by atmospheric release from the Kraton-3 accidental underground nuclear explosion. 2001-2002

    International Nuclear Information System (INIS)

    Ramzaev, V.; Golikov, V.; Mishine, A.; Kaduka, M.; Burtcev, I.; Gedeonov, A.; Bulatenkov, Y.U.; Strand, P.; Brown, J.

    2004-01-01

    Current distributions of artificial radionuclides (ARN) were studied in the main compartments of a larch-tree forest lethally affected by a radioactive release from the Kraton-3 peaceful underground nuclear explosion (65.9 deg N, 112.3 deg E; Yakutia, Russia; 1978). Samples of soil, fungi, lichens, mosses, grasses, shrubs and trees were obtained at points belonging to four zones categorised by the severity of the ecosystem damage. Sampling was supplemented by dose rate measurements in air and mapping. The area of forest characterised by 100% lethality to adult larches (Larix gmelinii) and with partial, visually-detectable damage of other more radio-resistance species (e.g. lichens, mosses) covers a territory of approximately 1.2 km 2 . Elevated levels of long-lived ARN were found at all sampling sites. Maximum registered levels of the ground contamination with radionuclides of Cs, Sr and Pu were three orders of magnitude higher than those expected from global fallout. The ratios of 137 Cs to some other significant radionuclides in the ground contamination were as follows [mean (range)]: 90 Sr - 0.57(0.02-0.93); 239,240 Pu 44(25-72); 60 Co 470(220-760). Twenty-three years after a discrete contamination event, 90-95% of the total deposited radiocesium and plutonium has still remained in the lichen-moss on-ground cover and in the top 5 cm organic soil layer. At the same time, vertical and horizontal migrations of 90 Sr in soil were more pronounced. Strong surface contamination with 137 Cs, 90 Sr and plutonium was detected at the twigs and bark of the dead larches. The young larches that grew at the contaminated area following the initial destruction of the forest demonstrated a substantial ability to accumulate 137 Cs, 90 Sr and plutonium via roots, while the bushes selectively accumulated mainly radiostrontium. In contrast, some fungi concentrated mostly radiocesium. The levels of gamma dose rate in air and the environmental contamination with 137 Cs were found to

  4. Injectable In-Situ Gelling Controlled Release Drug Delivery System

    OpenAIRE

    Kulwant Singh; S. L. HariKumar

    2012-01-01

    The administration of poorly bioavailable drug through parenteral route is regarded the most efficient for drug delivery. Parenteral delivery provides rapid onset even for the drug with narrow therapeutic window, but to maintain the systemic drug level repeated installation are required which cause the patient discomfort. This can be overcome by designing the drug into a system, which control the drug release even through parenteral delivery, which improve patient compliance as well as pharma...

  5. Controlling Object Heat Release Rate using Geometrical Features

    OpenAIRE

    Kraft, Stefan Marc

    2017-01-01

    An experimental study was conducted to determine the effect of complex geometries on the burning rate of materials made using additive manufacturing. Controlling heat release rate has applicability in limiting fire hazards as well as for designing fuels for optimal burning rate. The burning rate of a structure is a function of the material properties as well as the airflow through it, which is dictated by the geometry. This burning rate is generally proportional to the porosity for obj...

  6. PEDIC - A COMPUTER PROGRAM TO ESTIMATE THE EFFECT OF EVACUATION ON POPULATION EXPOSURE FOLLOWING ACUTE RADIONUCLIDE RELEASES TO THE ATOMSPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Strenge, D. L.; Peloquin, R. A.

    1981-01-01

    The computer program PEDIC is described for estimation of the effect of evacuation on population exposure. The program uses joint frequency, annual average meteorological data and a simple population evacuation model to estimate exposure reduction due to movement of people away from radioactive plumes following an acute release of activity. Atmospheric dispersion is based on a sector averaged Gaussian model with consideration of plume rise and building wake effects. Appendices to the report provide details of the computer program design, a program listing, input card preparation instructions and sample problems.

  7. SOL-Gel microspheres and nanospheres for controlled release applications

    International Nuclear Information System (INIS)

    Barbe, C.; Beyer, R.; Kong, L.; Blackford, M.; Trautman, R.; Bartlett, J.

    2002-01-01

    We present a novel approach to the synthesis of inorganic sol-gel microspheres for encapsulating organic and bioactive molecules, and controlling their subsequent release kinetics. The bioactive species are incorporated, at ambient temperature, into the inorganic particles using an emulsion gelation process. Independent control of the release rate (by adapting the nanostructure of the internal pore network to the physico-chemical properties of the bioactive molecules) and particle size (by tailoring the emulsion chemistry) is demonstrated. Sol-gel chemistry has been shown to be a flexible technique for producing inorganic silica matrices with tailored microstructures, which can be used for the encapsulation and controlled release of organic and bioactive molecules. The present paper extends this concept by combining sol-gel chemistry with an emulsion approach for producing inorganic particles with controlled dimensions, and demonstrates how the particle size and microstructure can be independently controlled. Sol-Gel Chemistry and Encapsulation of Model Compounds. A stock solution of 4-(2-hydroxy-l-naphthylazo) benzene sulfonic acid (Orange II) was produced by dissolving Orange II in water (0.1 wt%), and adjusting the pH to the required value. Sol-gel solutions were subsequently prepared by mixing the aqueous solution with tetramethylorthosilicate (TMOS) and methanol (MeOH), to achieve H 2 O:TMOS (W] and MeOH:TMOS mole ratios (D) of four. The resulting solution was stirred and left to age at ambient temperature for one day. A transparent emulsion was prepared by mixing selected surfactants and organic solvents. The surfactants used included sorbitan monooleate, sorbitan monolaurate and bis-2-ethylhexylsulfo-succinate (AOT), while the organic phase was typically chosen from the group consisting of kerosene, hexane, heptane, octane, decane, dodecane and cyclohexane. The sol-gel solution was added to the emulsion, and the resulting mixture was stirred at 500 rpm for

  8. Controlled release from bilayer-decorated magnetoliposomes via electromagnetic heating.

    Science.gov (United States)

    Chen, Yanjing; Bose, Arijit; Bothun, Geoffrey D

    2010-06-22

    Nanoscale assemblies that can be activated and controlled through external stimuli represent a next stage in multifunctional therapeutics. We report the formation, characterization, and release properties of bilayer-decorated magnetoliposomes (dMLs) that were prepared by embedding small hydrophobic SPIO nanoparticles at different lipid molecule to nanoparticle ratios within dipalmitoylphosphatidylcholine (DPPC) bilayers. The dML structure was examined by cryogenic transmission electron microscopy and differential scanning calorimetry, and release was examined by carboxyfluorescein leakage. Nanoparticle heating using alternating current electromagnetic fields (EMFs) operating at radio frequencies provided selective release of the encapsulated molecule at low nanoparticle concentrations and under physiologically acceptable EMF conditions. Without radio frequency heating, spontaneous leakage from the dMLs decreased with increasing nanoparticle loading, consistent with greater bilayer stability and a decrease in the effective dML surface area due to aggregation. With radio frequency heating, the initial rate and extent of leakage increased significantly as a function of nanoparticle loading and electromagnetic field strength. The mechanism of release is attributed to a combination of bilayer permeabilization and partial dML rupture.

  9. Controlled release of ibuprofen by meso-macroporous silica

    Science.gov (United States)

    Santamaría, E.; Maestro, A.; Porras, M.; Gutiérrez, J. M.; González, C.

    2014-02-01

    Structured meso-macroporous silica was successfully synthesized from an O/W emulsion using decane as a dispersed phase. Sodium silicate solution, which acts as a silica source and a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (EO19PO39EO19) denoted as P84 was used in order to stabilize the emulsion and as a mesopore template. The materials obtained were characterized through transmission electron microscopy (TEM), scanning electron microscopy (SEM), small-angle X-ray diffraction scattering (SAXS) and nitrogen adsorption-desorption isotherms. Ibuprofen (IBU) was selected as the model drug and loaded into ordered meso-macroporous materials. The effect of the materials’ properties on IBU drug loading and release was studied. The results showed that the loading of IBU increases as the macropore presence in the material is increased. The IBU adsorption process followed the Langmuir adsorption isotherm. A two-step release process, consisting of an initial fast release and then a slower release was observed. Macropores enhanced the adsorption capacity of the material; this was probably due to the fact that they allowed the drug to access internal pores. When only mesopores were present, ibuprofen was probably adsorbed on the mesopores close to the surface. Moreover, the more macropore present in the material, the slower the release behaviour observed, as the ibuprofen adsorbed in the internal pores had to diffuse along the macropore channels up to the surface of the material. The material obtained from a highly concentrated emulsion was functionalized with amino groups using two methods, the post-grafting mechanism and the co-condensation mechanism. Both routes improve IBU adsorption in the material and show good behaviour as a controlled drug delivery system.

  10. Development of controlled drug release systems based on thiolated polymers.

    Science.gov (United States)

    Bernkop-Schnürch, A; Scholler, S; Biebel, R G

    2000-05-03

    The purpose of the present study was to generate mucoadhesive matrix-tablets based on thiolated polymers. Mediated by a carbodiimide, L-cysteine was thereby covalently linked to polycarbophil (PCP) and sodium carboxymethylcellulose (CMC). The resulting thiolated polymers displayed 100+/-8 and 1280+/-84 micromol thiol groups per gram, respectively (means+/-S.D.; n=6-8). In aqueous solutions these modified polymers were capable of forming inter- and/or intramolecular disulfide bonds. The velocity of this process augmented with increase of the polymer- and decrease of the proton-concentration. The oxidation proceeded more rapidly within thiolated PCP than within thiolated CMC. Due to the formation of disulfide bonds within thiol-containing polymers, the stability of matrix-tablets based on such polymers could be strongly improved. Whereas tablets based on the corresponding unmodified polymer disintegrated within 2 h, the swollen carrier matrix of thiolated CMC and PCP remained stable for 6.2 h (mean, n=4) and more than 48 h, respectively. Release studies of the model drug rifampicin demonstrated that a controlled release can be provided by thiolated polymer tablets. The combination of high stability, controlled drug release and mucoadhesive properties renders matrix-tablets based on thiolated polymers useful as novel drug delivery systems.

  11. Design of a controlled release liquid formulation of lamotrigine

    Directory of Open Access Journals (Sweden)

    V Kumar

    2011-05-01

    Full Text Available "n  "n  Background and the purpose of the study: Lamotrigine is a broad spectrum anticonvulsant drug widely used as mono- or adjunct- therapy in adults and children. The aim of this study was to develop controlled release liquid formulation of lamotrigine to improve bioavailability and compliance of pediatric and geriatric epileptic patients. "n  Methods: Multiple (w/o/w emulsion was prepared using one step emulsification technique. It was evaluated for entrapment efficiency (EE, morphology, zeta potential (ZP, polydispersity index (PI, rheology, thermal property, in vitro drug release behavior and stability. In vivo studies in albino mice were carried out using maximal electroshock seizure (MES test and strychnine induced seizure (SIS pattern test and results were compared with marketed formulation. "n  Results: The EE of the formulations varied from 84.37% to 98.11%. The ZP and PI values of the prepared batches were in the range of +23.46 to +28.07 and 0.256 and 0.365, respectively. Microscopic observation clearly indicated the stability of the emulsions during the storage period. All batches exhibited controlled in vitro drug release up to 12 hrs. Batch C11 exhibited significantly longer duration of protection of seizure in mice against MES and exhibited comparable efficacy in SIS as compared to the marketed formulation. "n  Major Conclusion: Multiple emulsion of lamotrigine compared to the marketed tablet showed plasma drug concentration within therapeutic range for longer time and comparable efficacy.

  12. Newly developed controlled release subcutaneous formulation for tramadol hydrochloride

    Directory of Open Access Journals (Sweden)

    Mostafa Mabrouk

    2018-05-01

    Full Text Available This study presents a drug delivery system of poly (Ɛ-caprolactone (PCL ribbons to optimize the pharmaceutical action of tramadol for the first time according to our knowledge. PCL ribbons were fabricated and loaded with tramadol HCl. Ribbons were prepared by slip casting technique and coated with dipping technique with β-cyclodextrin. The chemical integrity and surface morphology of the ribbons were confirmed using FTIR and SEM coupled with EDX. In addition, thermodynamic behavior of the fabricated ribbons was investigated using DSC/TGA. Tramadol loading into PCL ribbons, biodegradation of ribbons and tramadol release kinetics were studied in PBS.The results revealed that the formulated composition did not affect the chemical integrity of the drug. Furthermore, SEM/EDX confirmed the inclusion of tramadol into the PCL matrix in homogenous distribution pattern without any observation of porous structure. The particle size of loaded tramadol was found to be in the range of (2–4 nm. The formulated composition did not affect the chemical integrity of the drug and should be further investigated for bioavailability. Tramadol exhibited controlled release behavior from PCL ribbons up to 45 days governed mainly by diffusion mechanism. The fabricated ribbons have a great potentiality to be implemented in the long term subcutaneous delivery of tramadol. Keywords: Tramadol, Polycaprolcatone, Subcutaneous membrane, Ribbons, β-Cyclodextrin, Controlled release

  13. Agricultural production - Phase 2. Indonesia. Controlled release pesticide formulations

    International Nuclear Information System (INIS)

    Vollner, L.

    1992-01-01

    At the request of the Government of Indonesia, an IAEA expert undertook a two weeks mission from 2 to 15 April 1991, and continued it from the 9 to 22 November 1991 at the Center for Application of Isotopes and Radiation (CAIR) of the National Atomic Energy Agency, BATAN in Jakarta. Expert discussed the project and carried out experiments together with the staff of the center, introducing shellac (description in part II) as a candidate for controlled release formulations. Formulations of carbofuran, butachlor, 2,4-D and diazinon were carried out, using sand and cocconut shells as carriers. Release rates of a.i. into water have been checked and further work has been discussed. Expert assessed further needs for supply of instruments, accessories and chemicals. (author)

  14. Controlled release of ibuprofen by meso–macroporous silica

    Energy Technology Data Exchange (ETDEWEB)

    Santamaría, E., E-mail: esthersantamaria@ub.edu; Maestro, A.; Porras, M.; Gutiérrez, J.M.; González, C.

    2014-02-15

    Structured meso–macroporous silica was successfully synthesized from an O/W emulsion using decane as a dispersed phase. Sodium silicate solution, which acts as a silica source and a poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (EO{sub 19}PO{sub 39}EO{sub 19}) denoted as P84 was used in order to stabilize the emulsion and as a mesopore template. The materials obtained were characterized through transmission electron microscopy (TEM), scanning electron microscopy (SEM), small-angle X-ray diffraction scattering (SAXS) and nitrogen adsorption–desorption isotherms. Ibuprofen (IBU) was selected as the model drug and loaded into ordered meso–macroporous materials. The effect of the materials’ properties on IBU drug loading and release was studied. The results showed that the loading of IBU increases as the macropore presence in the material is increased. The IBU adsorption process followed the Langmuir adsorption isotherm. A two-step release process, consisting of an initial fast release and then a slower release was observed. Macropores enhanced the adsorption capacity of the material; this was probably due to the fact that they allowed the drug to access internal pores. When only mesopores were present, ibuprofen was probably adsorbed on the mesopores close to the surface. Moreover, the more macropore present in the material, the slower the release behaviour observed, as the ibuprofen adsorbed in the internal pores had to diffuse along the macropore channels up to the surface of the material. The material obtained from a highly concentrated emulsion was functionalized with amino groups using two methods, the post-grafting mechanism and the co-condensation mechanism. Both routes improve IBU adsorption in the material and show good behaviour as a controlled drug delivery system. - Graphical abstract: Ibuprofen release profiles for the materials obtained from samples P84{sub m}eso (black diamonds), P84{sub 2}0% (white squares), P84{sub 5

  15. Controlled release of ibuprofen by meso–macroporous silica

    International Nuclear Information System (INIS)

    Santamaría, E.; Maestro, A.; Porras, M.; Gutiérrez, J.M.; González, C.

    2014-01-01

    Structured meso–macroporous silica was successfully synthesized from an O/W emulsion using decane as a dispersed phase. Sodium silicate solution, which acts as a silica source and a poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (EO 19 PO 39 EO 19 ) denoted as P84 was used in order to stabilize the emulsion and as a mesopore template. The materials obtained were characterized through transmission electron microscopy (TEM), scanning electron microscopy (SEM), small-angle X-ray diffraction scattering (SAXS) and nitrogen adsorption–desorption isotherms. Ibuprofen (IBU) was selected as the model drug and loaded into ordered meso–macroporous materials. The effect of the materials’ properties on IBU drug loading and release was studied. The results showed that the loading of IBU increases as the macropore presence in the material is increased. The IBU adsorption process followed the Langmuir adsorption isotherm. A two-step release process, consisting of an initial fast release and then a slower release was observed. Macropores enhanced the adsorption capacity of the material; this was probably due to the fact that they allowed the drug to access internal pores. When only mesopores were present, ibuprofen was probably adsorbed on the mesopores close to the surface. Moreover, the more macropore present in the material, the slower the release behaviour observed, as the ibuprofen adsorbed in the internal pores had to diffuse along the macropore channels up to the surface of the material. The material obtained from a highly concentrated emulsion was functionalized with amino groups using two methods, the post-grafting mechanism and the co-condensation mechanism. Both routes improve IBU adsorption in the material and show good behaviour as a controlled drug delivery system. - Graphical abstract: Ibuprofen release profiles for the materials obtained from samples P84 m eso (black diamonds), P84 2 0% (white squares), P84 5 0% (black triangles), P84 7

  16. Migration of radionuclides through a river system

    Energy Technology Data Exchange (ETDEWEB)

    Matsunaga, Takeshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1999-03-01

    Migration behavior of several atmospherically-derived radionuclides in a river watershed was studied. A main interest was in their relocation from the ground soil of the watershed to a downstream region through a river. Studied radionuclides are: {sup 137}Cs generated by weapon tests in the atmosphere; {sup 210}Pb and {sup 7}Be of naturally occurring radionuclides; {sup 137}Cs, {sup 90}Sr, {sup 239,240}Pu and {sup 241}Am released by the Chernobyl nuclear power plant accident. Dominance of the form in suspended solid in river water (particulate form) was qualified for the radionuclides in the Kuji river watershed. An importance of discharge in flooding was also confirmed. A historical budget analysis for weapon test derived {sup 137}Cs was presented for the Hi-i river watershed and its accompanied lake sediment (Lake Shinji). The work afforded a scheme of a fate of {sup 137}Cs after falling on the ground soil and on the lake surface. Several controlling factors, which can influence on the chemical form of radionuclides discharged to a river, were also investigated in the vicinity of the Chernobyl nuclear power plant. A special attention was paid on the association of the radionuclides with dissolved species in water. Preferential association of Pu and Am isotopes to a large molecular size of dissolved matrices, probably of humic substances, was suggested. (author)

  17. Use of radioanalytical methods for the control of contamination of environmental objects with radionuclides

    International Nuclear Information System (INIS)

    Zimakov, E.I.; Lazarev, V.N.

    1983-01-01

    Stable isotope and non isotope carriers (their chemical form and quantity) exert: strong influence on regularities of radionuclide migration by biologic and food chains. The method of multiple isotope dilution enables one to identify and quantitatively estimate radionuclide and its isotope carrier content and in a number of cases to find out chemical form of element dislocation in the determined sample also with quantitative estimation

  18. Recommendations to the Technical Steering Panel regarding approach for estimating individual radiation doses resulting from releases of radionuclides to the Columbia River

    International Nuclear Information System (INIS)

    Brothers, A.J.; Napier, B.A.

    1992-08-01

    At the direction of the Technical Steering Panel (TSP) of the Hanford Environmental Dose Reconstruction (HEDR) Project, Battelle staff have reviewed and analyzed available data regarding possible historical radiation doses to individuals resulting from radionuclide releases to the Columbia River. The objective of this review was to recommend to the TSP the spatial and temporal scope and level of effort on Columbia River work to most effectively extend work performed in Phase I of the project to meet the project objectives. Four stretches of the Columbia River and adjacent Pacific coastal waters were defined and investigated for four time periods. Radiation doses arising from ten potentially major exposure pathways were evaluated for each of the time/location combinations, and several alternative methods were defined for estimating the doses from each pathway. Preliminary cost estimates were also developed for implementing dose estimation activities for each of the possible combinations. The number of combinations of the alternatives is obviously very large. A ''value of information'' (VOI) decision analysis tool was developed and applied to the problem of selecting a few ''optimal'' sets of alternatives to consider. This VOI analysis relies on both available data and the judgement of technical experts. Input data and the algorithms used are described

  19. A Glutamate Homeostat Controls the Presynaptic Inhibition of Neurotransmitter Release

    Directory of Open Access Journals (Sweden)

    Xiling Li

    2018-05-01

    Full Text Available Summary: We have interrogated the synaptic dialog that enables the bi-directional, homeostatic control of presynaptic efficacy at the glutamatergic Drosophila neuromuscular junction (NMJ. We find that homeostatic depression and potentiation use disparate genetic, induction, and expression mechanisms. Specifically, homeostatic potentiation is achieved through reduced CaMKII activity postsynaptically and increased abundance of active zone material presynaptically at one of the two neuronal subtypes innervating the NMJ, while homeostatic depression occurs without alterations in CaMKII activity and is expressed at both neuronal subtypes. Furthermore, homeostatic depression is only induced through excess presynaptic glutamate release and operates with disregard to the postsynaptic response. We propose that two independent homeostats modulate presynaptic efficacy at the Drosophila NMJ: one is an intercellular signaling system that potentiates synaptic strength following diminished postsynaptic excitability, while the other adaptively modulates presynaptic glutamate release through an autocrine mechanism without feedback from the postsynaptic compartment. : Homeostatic mechanisms stabilize synaptic strength, but the signaling systems remain enigmatic. Li et al. suggest the existence of a homeostat operating at the Drosophila neuromuscular junction that responds to excess glutamate through an autocrine mechanism to adaptively inhibit presynaptic neurotransmitter release. This system parallels forms of plasticity at central synapses. Keywords: homeostatic synaptic plasticity, glutamate homeostasis, synaptic depression, Drosophila neuromuscular junction

  20. Tunable controlled release of molecular species from Halloysite nanotubes

    Science.gov (United States)

    Elumalai, Divya Narayan

    Encouraged by potential applications in rust coatings, self-healing composites, selective delivery of drugs, and catalysis, the transport of molecular species through Halloysite nanotubes (HNTs), specifically the storage and controlled release of these molecules, has attracted strong interest in recent years. HNTs are a naturally occurring biocompatible nanomaterial that are abundantly and readily available. They are alumosilicate based tubular clay nanotubes with an inner lumen of 15 nm and a length of 600-900 nm. The size of the inner lumen of HNTs may be adjusted by etching. The lumen can be loaded with functional agents like antioxidants, anticorrosion agents, flame-retardant agents, drugs, or proteins, allowing for a sustained release of these agents for hours. The release times can be further tuned for days and months by the addition of tube end-stoppers. In this work a three-dimensional, time-quantified Monte Carlo model that efficiently describes diffusion through and from nanotubes is implemented. Controlled delivery from Halloysite Nanotubes (HNT) is modeled based on interactions between the HNT's inner wall and the nanoparticles (NP) and among NPs themselves. The model was validated using experimental data published in the literature. The validated model is then used to study the effect of multiple parameters like HNT diameter and length, particle charge, ambient temperature and the creation of smart caps at the tube ends on the release of encapsulated NPs. The results show that release profiles depend on the size distribution of the HNT batch used for the experiment, as delivery is sensitive to HNT lumen and length. The effect of the addition of end-caps to the HNTs, on the rate of release of encapsulated NPs is also studied here. The results show that the release profiles are significantly affected by the addition of end caps to the HNTs and is sensitive to the end-cap pore lumen. A very good agreement with the experiment is observed when a weight

  1. Controlled release and intracellular protein delivery from mesoporous silica nanoparticles.

    Science.gov (United States)

    Deodhar, Gauri V; Adams, Marisa L; Trewyn, Brian G

    2017-01-01

    Protein therapeutics are promising candidates for disease treatment due to their high specificity and minimal adverse side effects; however, targeted protein delivery to specific sites has proven challenging. Mesoporous silica nanoparticles (MSN) have demonstrated to be ideal candidates for this application, given their high loading capacity, biocompatibility, and ability to protect host molecules from degradation. These materials exhibit tunable pore sizes, shapes and volumes, and surfaces which can be easily functionalized. This serves to control the movement of molecules in and out of the pores, thus entrapping guest molecules until a specific stimulus triggers release. In this review, we will cover the benefits of using MSN as protein therapeutic carriers, demonstrating that there is great diversity in the ways MSN can be used to service proteins. Methods for controlling the physical dimensions of pores via synthetic conditions, applications of therapeutic protein loaded MSN materials in cancer therapies, delivering protein loaded MSN materials to plant cells using biolistic methods, and common stimuli-responsive functionalities will be discussed. New and exciting strategies for controlled release and manipulation of proteins are also covered in this review. While research in this area has advanced substantially, we conclude this review with future challenges to be tackled by the scientific community. Copyright © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Electrically controlled drug release from nanostructured polypyrrole coated on titanium

    International Nuclear Information System (INIS)

    Sirivisoot, Sirinrath; Pareta, Rajesh; Webster, Thomas J

    2011-01-01

    Previous studies have demonstrated that multi-walled carbon nanotubes grown out of anodized nanotubular titanium (MWNT-Ti) can be used as a sensing electrode for various biomedical applications; such sensors detected the redox reactions of certain molecules, specifically proteins deposited by osteoblasts during extracellular matrix bone formation. Since it is known that polypyrrole (PPy) can release drugs upon electrical stimulation, in this study antibiotics (penicillin/streptomycin, P/S) or an anti-inflammatory drug (dexamethasone, Dex), termed PPy[P/S] or PPy[Dex], respectively, were electrodeposited in PPy on titanium. The objective of the present study was to determine if such drugs can be released from PPy on demand and (by applying a voltage) control cellular behavior important for orthopedic applications. Results showed that PPy films possessed nanometer-scale roughness as analyzed by atomic force microscopy. X-ray photoelectron spectroscopy confirmed the presence of P/S and Dex encapsulated within the PPy films. Results from cyclic voltammetry showed that 80% of the drugs were released on demand when sweep voltages were applied for five cycles at a scan rate of 0.1 V s -1 . Furthermore, osteoblast (bone-forming cells) and fibroblast (fibrous tissue-forming cells) adhesion were determined on the PPy films. Results showed that PPy[Dex] enhanced osteoblast adhesion after 4 h of culture compared to plain Ti. PPy-Ti (with or without anionic drug doping) inhibited fibroblast adhesion compared to plain Ti. These in vitro results confirmed that electrodeposited PPy[P/S] and PPy[Dex] can release drugs on demand to potentially fight bacterial infection, reduce inflammation, promote bone growth or reduce fibroblast functions, further implicating the use of such materials as implant sensors.

  3. Electrically controlled drug release from nanostructured polypyrrole coated on titanium

    Science.gov (United States)

    Sirivisoot, Sirinrath; Pareta, Rajesh; Webster, Thomas J.

    2011-02-01

    Previous studies have demonstrated that multi-walled carbon nanotubes grown out of anodized nanotubular titanium (MWNT-Ti) can be used as a sensing electrode for various biomedical applications; such sensors detected the redox reactions of certain molecules, specifically proteins deposited by osteoblasts during extracellular matrix bone formation. Since it is known that polypyrrole (PPy) can release drugs upon electrical stimulation, in this study antibiotics (penicillin/streptomycin, P/S) or an anti-inflammatory drug (dexamethasone, Dex), termed PPy[P/S] or PPy[Dex], respectively, were electrodeposited in PPy on titanium. The objective of the present study was to determine if such drugs can be released from PPy on demand and (by applying a voltage) control cellular behavior important for orthopedic applications. Results showed that PPy films possessed nanometer-scale roughness as analyzed by atomic force microscopy. X-ray photoelectron spectroscopy confirmed the presence of P/S and Dex encapsulated within the PPy films. Results from cyclic voltammetry showed that 80% of the drugs were released on demand when sweep voltages were applied for five cycles at a scan rate of 0.1 V s - 1. Furthermore, osteoblast (bone-forming cells) and fibroblast (fibrous tissue-forming cells) adhesion were determined on the PPy films. Results showed that PPy[Dex] enhanced osteoblast adhesion after 4 h of culture compared to plain Ti. PPy-Ti (with or without anionic drug doping) inhibited fibroblast adhesion compared to plain Ti. These in vitro results confirmed that electrodeposited PPy[P/S] and PPy[Dex] can release drugs on demand to potentially fight bacterial infection, reduce inflammation, promote bone growth or reduce fibroblast functions, further implicating the use of such materials as implant sensors.

  4. Electrically controlled drug release from nanostructured polypyrrole coated on titanium

    Energy Technology Data Exchange (ETDEWEB)

    Sirivisoot, Sirinrath; Pareta, Rajesh; Webster, Thomas J, E-mail: Thomas_Webster@Brown.edu [School of Engineering, Brown University, Providence, RI 02912 (United States)

    2011-02-25

    Previous studies have demonstrated that multi-walled carbon nanotubes grown out of anodized nanotubular titanium (MWNT-Ti) can be used as a sensing electrode for various biomedical applications; such sensors detected the redox reactions of certain molecules, specifically proteins deposited by osteoblasts during extracellular matrix bone formation. Since it is known that polypyrrole (PPy) can release drugs upon electrical stimulation, in this study antibiotics (penicillin/streptomycin, P/S) or an anti-inflammatory drug (dexamethasone, Dex), termed PPy[P/S] or PPy[Dex], respectively, were electrodeposited in PPy on titanium. The objective of the present study was to determine if such drugs can be released from PPy on demand and (by applying a voltage) control cellular behavior important for orthopedic applications. Results showed that PPy films possessed nanometer-scale roughness as analyzed by atomic force microscopy. X-ray photoelectron spectroscopy confirmed the presence of P/S and Dex encapsulated within the PPy films. Results from cyclic voltammetry showed that 80% of the drugs were released on demand when sweep voltages were applied for five cycles at a scan rate of 0.1 V s{sup -1}. Furthermore, osteoblast (bone-forming cells) and fibroblast (fibrous tissue-forming cells) adhesion were determined on the PPy films. Results showed that PPy[Dex] enhanced osteoblast adhesion after 4 h of culture compared to plain Ti. PPy-Ti (with or without anionic drug doping) inhibited fibroblast adhesion compared to plain Ti. These in vitro results confirmed that electrodeposited PPy[P/S] and PPy[Dex] can release drugs on demand to potentially fight bacterial infection, reduce inflammation, promote bone growth or reduce fibroblast functions, further implicating the use of such materials as implant sensors.

  5. Methods of Increasing the Performance of Radionuclide Generators Used in Nuclear Medicine: Daughter Nuclide Build-Up Optimisation, Elution-Purification-Concentration Integration, and Effective Control of Radionuclidic Purity

    Directory of Open Access Journals (Sweden)

    Van So Le

    2014-06-01

    Full Text Available Methods of increasing the performance of radionuclide generators used in nuclear medicine radiotherapy and SPECT/PET imaging were developed and detailed for 99Mo/99mTc and 68Ge/68Ga radionuclide generators as the cases. Optimisation methods of the daughter nuclide build-up versus stand-by time and/or specific activity using mean progress functions were developed for increasing the performance of radionuclide generators. As a result of this optimisation, the separation of the daughter nuclide from its parent one should be performed at a defined optimal time to avoid the deterioration in specific activity of the daughter nuclide and wasting stand-by time of the generator, while the daughter nuclide yield is maintained to a reasonably high extent. A new characteristic parameter of the formation-decay kinetics of parent/daughter nuclide system was found and effectively used in the practice of the generator production and utilisation. A method of “early elution schedule” was also developed for increasing the daughter nuclide production yield and specific radioactivity, thus saving the cost of the generator and improving the quality of the daughter radionuclide solution. These newly developed optimisation methods in combination with an integrated elution-purification-concentration system of radionuclide generators recently developed is the most suitable way to operate the generator effectively on the basis of economic use and improvement of purposely suitable quality and specific activity of the produced daughter radionuclides. All these features benefit the economic use of the generator, the improved quality of labelling/scan, and the lowered cost of nuclear medicine procedure. Besides, a new method of quality control protocol set-up for post-delivery test of radionuclidic purity has been developed based on the relationship between gamma ray spectrometric detection limit, required limit of impure radionuclide activity and its measurement

  6. Assessment of Radionuclides in the Savannah River Site Environment Summary

    Energy Technology Data Exchange (ETDEWEB)

    Carlton, W.H.

    1999-01-26

    This document summarizes the impact of radionuclide releases from Savannah River Site (SRS) facilities from 1954 through 1996. The radionuclides reported here are those whose release resulted in the highest dose to people living near SRS.

  7. Investigating the in vitro drug release kinetics from controlled release diclofenac potassium-ethocel matrix tablets and the influence of co-excipients on drug release patterns.

    Science.gov (United States)

    Shah, Shefaat Ullah; Shah, Kifayat Ullah; Rehman, Asimur; Khan, Gul Majid

    2011-04-01

    The objective of the study was to formulate and evaluate controlled release polymeric tablets of Diclofenac Potassium for the release rate, release patterns and the mechanism involved in the release process of the drug. Formulations with different types and grades of Ethyl Cellulose Ether derivatives in several drug-to-polymer ratios (D:P) were compressed into tablets using the direct compression method. In vitro drug release studies were performed in phosphate buffer (pH 7.4) as dissolution medium by using USP Method-1 (Rotating Basket Method). Similarity factor f2 and dissimilarity factor f1 were applied for checking the similarities and dissimilarities of the release profiles of different formulations. For the determination of the release mechanism and drug release kinetics various mathematical/kinetic models were employed. It was found that all of the Ethocel polymers could significantly slow down the drug release rate with Ethocel FP polymers being the most efficient, especially at D:P ratios of 10:03 which lead towards the achievement of zero or near zero order release kinetics.

  8. Contact lenses as drug controlled release systems: a narrative review

    Directory of Open Access Journals (Sweden)

    Helena Prior Filipe

    2016-06-01

    Full Text Available ABSTRACT Topically applied therapy is the most common way to treat ocular diseases, however given the anatomical and physiological constraints of the eye, frequent dosing is required with possible repercussions in terms of patient compliance. Beyond refractive error correction, contact lenses (CLs have, in the last few decades emerged as a potential ophthalmic drug controlled release system (DCRS. Extensive research is underway to understand how to best modify CLs to increase residence time and bioavailability of drugs within therapeutic levels on the ocular surface.These devices may simultaneously correct ametropia and have a role in managing ophthalmic disorders that can hinder CL wear such as dry eye, glaucoma, ocular allergy and cornea infection and injury. In this narrative review the authors explain how the ocular surface structures determine drug diffusion in the eye and summarize the strategies to enhance drug residence time and bioavailability. They synthesize findings and clinical applications of drug soaked CLs as DCRS combined with delivery diffusion barriers, incorporation of functional monomers, ion related controlled release, molecular imprinting, nanoparticles and layering. The authors draw conclusions about the impact of these novel ophthalmic agents delivery systems in improving drug transport in the target tissue and patient compliance, in reducing systemic absorption and undesired side effects, and discuss future perspectives.

  9. A concise review on smart polymers for controlled drug release.

    Science.gov (United States)

    Aghabegi Moghanjoughi, Arezou; Khoshnevis, Dorna; Zarrabi, Ali

    2016-06-01

    Design and synthesis of efficient drug delivery systems are of critical importance in health care management. Innovations in materials chemistry especially in polymer field allows introduction of advanced drug delivery systems since polymers could provide controlled release of drugs in predetermined doses over long periods, cyclic and tunable dosages. To this end, researchers have taken advantages of smart polymers since they can undergo large reversible, chemical, or physical fluctuations as responses to small changes in environmental conditions, for instance, in pH, temperature, light, and phase transition. The present review aims to highlight various kinds of smart polymers, which are used in controlled drug delivery systems as well as mechanisms of action and their applications.

  10. Estimated airborne release of radionuclides from the Battelle Memorial Institute Columbus Laboratories JN-1b building at the West Jefferson site as a result of postulated damage from severe wind and earthquake hazard

    International Nuclear Information System (INIS)

    Mishima, J.; Ayer, J.E.

    1981-11-01

    The potential airborne releases of radionuclides (source terms) that could result from wind and earthquake dmage are estimated for the Battelle Memorial Institute Columbus Laboratories JN-1b Building at the West Jefferson site in Ohio. The estimated source terms are based on the damage to barriers containing the radionuclides, the inventory of radionuclides at risk, and the fraction of the inventory made airborne as a result of the loss of containment. In an attempt to provide a realistic range of potential source terms that include most of the normal operating conditions, a best estimate bounded by upper and lower limits is calculated by combining the upper-bound, best-estimate, and lower-bound inventories-at-risk with an airborne release factor (upper-bound, best-estimate, and lower-bound if possible) for the situation. The factors used to evaluate the fractional airborne release of materials and the exchange rates between enclosed and exterior atmospheres are discussed. The postulated damage and source terms are discussed for wind and earthquake hazard scenarios in order of their increasing severity

  11. Controlled release of biofunctional substances by radiation-induced polymerization

    International Nuclear Information System (INIS)

    Yoshida, M.; Kumakura, M.; Kaetsu, I.

    1978-01-01

    The release behaviour of a drug from flat circular capsules obtained by radiation-induced polymerization at low temperatures and with different hydrophilic properties has been studied. The effect of various factors on release property was investigated. The release process could be divided into three parts, an initial quick release stage, stationary state release stage and a retarded release stage. Release behaviour in the stationary state was examined using Noyes-Whitney and Higuchi equations. It was shown that the hydrophilic property of polymer matrix expressed by water content was the most important effect on diffusion and release rate. Rigidity of the polymer may also affect diffusivity. The first quick release step could be attributed to rapid dissolution of drug in the matrix surface due to polymer swelling. (author)

  12. Estimation of the environmental or radiological impact in the event of accidental release of radionuclides in a DCLL fusion reactor; Estimacion del impacto radiologico ambiental en caso de liberacion accidental de radionucleidos en un reactor de fusion DCLL

    Energy Technology Data Exchange (ETDEWEB)

    Palermo, I.; Gomez Ros, J. M.; Sanz, J.; Mota, F.

    2013-07-01

    Tritium production and activation in the LiPb products can pose a radiological risk in the event of accidental release in a fusion reactor. Within the research programme Consolider TECNO{sub F}US (CSD2008-079) fusion technology has developed a design for a reactor with regenerative wrap with dual refrigeration (DCLL). The purpose of this communication is to present estimates of the radiological impact derived from an accidental release of radionuclides from the circuit of LiPb provinients. (Author)

  13. Uptake by benthic algae of critical radionuclides to be released in the liquid effluent of the Angra dos Reis Nuclear Power Plant, R.J., Brazil

    International Nuclear Information System (INIS)

    Guimaraes, J.R.D.

    1982-06-01

    In vitro interaction of benthic algae from the Angra dos Reis region, R.J., Brazil, was studied with critical radionuclides to be released in the liquid effluent of CNAAA (unit I). 137 Cs- 60 Co - and 125 I uptake and loss by Sargassum filipendula, Padina Vickersiae and Acanthophora Spicifera were observed. Biological half-lives and bioaccumulation factors (B.F.) were estimated. Co and I uptake were fast (apparent equilibrium in 3 to 7 days). Cs uptake was slower (2 to 3 weeks). Loss followed an inverse pattern (fast for Cs, slow for Co and I). B.F. ranged from 10 1 for Cs, to 10 3 for I and 10 3 -10 4 for Co. Higher B.F. for Co and I were found for P. vickersiae (up to 1,4 X 10 4 ) an A. spicifera (up to 7 X 10 3 ) respectively. These species represent important potential media for the transference of Co-I-and-to a much lesser extent - Cs isotopes, through food-webs. They exhibited high capacity to compete with local sandy sediments for the retention of Co and I. High B.F., rapid uptake and moderate to long biological half-lives enable S. filipendula, P. vickersiae and A. specifera to be powerful aids in the monitoring of radioactive contamination by Co and I isotopes. Since the majority of marine organisms tends to exhibit Cs B.F. similars to those reported here, these algae may also be used as monitors for Cs isotopes, the low B.F. being compensated by their abundance, wide distribution and facility of collection. (M.A.) [pt

  14. Halloysite Nanotubes: Controlled Access and Release by Smart Gates.

    Science.gov (United States)

    Cavallaro, Giuseppe; Danilushkina, Anna A; Evtugyn, Vladimir G; Lazzara, Giuseppe; Milioto, Stefana; Parisi, Filippo; Rozhina, Elvira V; Fakhrullin, Rawil F

    2017-07-28

    Hollow halloysite nanotubes have been used as nanocontainers for loading and for the triggered release of calcium hydroxide for paper preservation. A strategy for placing end-stoppers into the tubular nanocontainer is proposed and the sustained release from the cavity is reported. The incorporation of Ca(OH)₂ into the nanotube lumen, as demonstrated using transmission electron microscopy (TEM) imaging and Energy Dispersive X-ray (EDX) mapping, retards the carbonatation, delaying the reaction with CO₂ gas. This effect can be further controlled by placing the end-stoppers. The obtained material is tested for paper deacidification. We prove that adding halloysite filled with Ca(OH)₂ to paper can reduce the impact of acid exposure on both the mechanical performance and pH alteration. The end-stoppers have a double effect: they preserve the calcium hydroxide from carbonation, and they prevent from the formation of highly basic pH and trigger the response to acid exposure minimizing the pH drop-down. These features are promising for a composite nanoadditive in the smart protection of cellulose-based materials.

  15. A mathematical model for predicting the probability of acute mortality in a human population exposed to accidentally released airborne radionuclides. Final report for Phase I of the project: early effects of inhaled radionuclides

    International Nuclear Information System (INIS)

    Filipy, R.E.; Borst, F.J.; Cross, F.T.; Park, J.F.; Moss, O.R.

    1980-06-01

    The report presents a mathematical model for the purpose of predicting the fraction of human population which would die within 1 year of an accidental exposure to airborne radionuclides. The model is based on data from laboratory experiments with rats, dogs and baboons, and from human epidemiological data. Doses from external, whole-body irradiation and from inhaled, alpha- and beta-emitting radionuclides are calculated for several organs. The probabilities of death from radiation pneumonitis and from bone marrow irradiation are predicted from doses accumulated within 30 days of exposure to the radioactive aerosol. The model is compared with existing similar models under hypothetical exposure conditions. Suggestions for further experiments with inhaled radionuclides are included

  16. Agricultural production - Phase 2. Indonesia. Controlled release pesticide formulations

    International Nuclear Information System (INIS)

    Vollner, L.

    1991-01-01

    At the request of the Government of Indonesia, an IAEA expert undertook a two weeks (of one month) mission from 2 to 15 April 1991 to the Center for Application of Isotopes and Radiation (CAIR) of BATAN in Jakarta. Expert held a seminar, discussed and carried out experiments on Controlled Release Formulations (CRF). Discussed further experiments, cleaned and reinstalled an ECD of the Shimadzu gas chromatograph and optimized the analytical conditions for chlorinated pesticides. He also developed a project for possible submission to the Government of Germany, to allow the staff of CAIR to undertake a more intensive research and to be able to set up training facilities in his research center in Munich/Germany. He furthermore assessed needs for supply of instruments, accessories and radiolabelled pesticides. An agreement for continuing the scientific and technical mission was obtained with the staff of CAIR, in connection with the DDT-RCM at the end of November 1991, provided approval by IAEA

  17. Controlled Pesticide Release from Porous Composite Hydrogels Based on Lignin and Polyacrylic Acid

    Directory of Open Access Journals (Sweden)

    Yajie Sun

    2016-01-01

    Full Text Available For the controlled release of pesticides, a novel composite porous hydrogel (LBPAA was prepared based on lignin and polyacrylic acid for use as the support frame of a pore structure for water delivery. The LBPAA was analyzed to determine its water-swelling and slow release properties. The controlled release properties of LBPAA were evaluated through experiments in relation to the cumulative release of pesticides, with particular emphasis on environmental effects and release models. The porous LBPAA hydrogel showed improved properties compared to polyacrylic acid, and could therefore be considered an efficient material for application in controlled release systems in agriculture.

  18. Critical review of controlled release packaging to improve food safety and quality.

    Science.gov (United States)

    Chen, Xi; Chen, Mo; Xu, Chenyi; Yam, Kit L

    2018-03-19

    Controlled release packaging (CRP) is an innovative technology that uses the package to release active compounds in a controlled manner to improve safety and quality for a wide range of food products during storage. This paper provides a critical review of the uniqueness, design considerations, and research gaps of CRP, with a focus on the kinetics and mechanism of active compounds releasing from the package. Literature data and practical examples are presented to illustrate how CRP controls what active compounds to release, when and how to release, how much and how fast to release, in order to improve food safety and quality.

  19. Externally controlled triggered-release of drug from PLGA micro and nanoparticles.

    Directory of Open Access Journals (Sweden)

    Xin Hua

    Full Text Available Biofilm infections are extremely hard to eradicate and controlled, triggered and controlled drug release properties may prolong drug release time. In this study, the ability to externally control drug release from micro and nanoparticles was investigated. We prepared micro/nanoparticles containing ciprofloxacin (CIP and magnetic nanoparticles encapsulated in poly (lactic-co-glycolic acid PLGA. Both micro/nanoparticles were observed to have narrow size distributions. We investigated and compared their passive and externally triggered drug release properties based on their different encapsulation structures for the nano and micro systems. In passive release studies, CIP demonstrated a fast rate of release in first 2 days which then slowed and sustained release for approximately 4 weeks. Significantly, magnetic nanoparticles containing systems all showed ability to have triggered drug release when exposed to an external oscillating magnetic field (OMF. An experiment where the OMF was turned on and off also confirmed the ability to control the drug release in a pulsatile manner. The magnetically triggered release resulted in a 2-fold drug release increase compared with normal passive release. To confirm drug integrity following release, the antibacterial activity of released drug was evaluated in Pseudomonas aeruginosa biofilms in vitro. CIP maintained its antimicrobial activity after encapsulation and triggered release.

  20. Externally controlled triggered-release of drug from PLGA micro and nanoparticles.

    Science.gov (United States)

    Hua, Xin; Tan, Shengnan; Bandara, H M H N; Fu, Yujie; Liu, Siguo; Smyth, Hugh D C

    2014-01-01

    Biofilm infections are extremely hard to eradicate and controlled, triggered and controlled drug release properties may prolong drug release time. In this study, the ability to externally control drug release from micro and nanoparticles was investigated. We prepared micro/nanoparticles containing ciprofloxacin (CIP) and magnetic nanoparticles encapsulated in poly (lactic-co-glycolic acid) PLGA. Both micro/nanoparticles were observed to have narrow size distributions. We investigated and compared their passive and externally triggered drug release properties based on their different encapsulation structures for the nano and micro systems. In passive release studies, CIP demonstrated a fast rate of release in first 2 days which then slowed and sustained release for approximately 4 weeks. Significantly, magnetic nanoparticles containing systems all showed ability to have triggered drug release when exposed to an external oscillating magnetic field (OMF). An experiment where the OMF was turned on and off also confirmed the ability to control the drug release in a pulsatile manner. The magnetically triggered release resulted in a 2-fold drug release increase compared with normal passive release. To confirm drug integrity following release, the antibacterial activity of released drug was evaluated in Pseudomonas aeruginosa biofilms in vitro. CIP maintained its antimicrobial activity after encapsulation and triggered release.

  1. Factors controlling alkalisalt deposition in recovery boiler- release mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    McKeough, P.; Kylloenen, H.; Kurkela, M. [VTT Energy, Espoo (Finland). Process Technology Group

    1996-12-01

    As part of a cooperative effort to develop a model to describe the behaviour of inorganic compounds in kraft recovery boilers, an experimental investigation of the release of sulphur during black liquor pyrolysis has been undertaken. Previous to these studies, the mechanisms of sulphur release and the reasons for the observed effects of process conditions on sulphur release were very poorly understood. On the basis of the experimental results, the main reactions leading to sulphur release have been elucidated with a fair degree of certainty. Logical explanations for the variations of sulphur release with temperature and with liquor solids content have been proposed. The influence of pressure has been investigated in order to gain insights into the effects of mass transfer on the sulphur-release rate. In the near future, the research will be aimed at generating the kinetic data necessary for modelling the release of sulphur in the recovery furnace. (author)

  2. Effect of diltiazem on myocardial infarct size estimated by enzyme release, serial thallium-201 single-photon emission computed tomography and radionuclide angiography

    International Nuclear Information System (INIS)

    Zannad, F.; Amor, M.; Karcher, G.; Maurin, P.; Ethevenot, G.; Sebag, C.; Bertrand, A.; Pernot, C.; Gilgenkrantz, J.M.

    1988-01-01

    Diltiazem is a calcium antagonist with demonstrated experimental cardioprotective effects. Its effects on myocardial infarct size were studied in 34 patients admitted within 6 hours after the first symptoms of acute myocardial infarction. These patients were randomized, double-blind to placebo or diltiazem (10-mg intravenous bolus followed by 15 mg/hr intravenous infusion during 72 hours, followed by 4 X 60 mg during 21 days). Myocardial infarct size was assessed by plasma creatine kinase and creatine kinase-MB indexes, perfusion defect scores using single-photon emission computed tomography with thallium-201 and left ventricular ejection fraction measured by radionuclide angiography. Tomographic and angiographic scanning was performed serially before randomization, after 48 hours and 21 days later. Groups were comparable in terms of age, sex, inclusion time and baseline infarct location and size. Results showed no difference in creatine kinase and creatine kinase-MB data between controls and treated patients, a significant decrease in the perfusion defect scores in the diltiazem group (+0.1 +/- 3.0 placebo vs -2.2 +/- 1.9 diltiazem, p less than 0.02) and a better ejection fraction recovery in the diltiazem group (-4.2 +/- 7.4 placebo vs +7.7 +/- 11.2 diltiazem, p less than 0.05). Myocardial infarct size estimates from perfusion defect scores and enzyme data were closely correlated. These preliminary results suggest that diltiazem may reduce ischemic injury in acute myocardial infarction

  3. Controlled release system for ametryn using polymer microspheres: Preparation, characterization and release kinetics in water

    International Nuclear Information System (INIS)

    Grillo, Renato; Pereira, Anderson do Espirito Santo; Ferreira Silva de Melo, Nathalie; Porto, Raquel Martins; Feitosa, Leandro Oliveira; Tonello, Paulo Sergio; Dias Filho, Newton L.; Rosa, Andre Henrique; Lima, Renata; Fraceto, Leonardo Fernandes

    2011-01-01

    The purpose of this work was to develop a modified release system for the herbicide ametryn by encapsulating the active substance in biodegradable polymer microparticles produced using the polymers poly(hydroxybutyrate) (PHB) or poly(hydroxybutyrate-valerate) (PHBV), in order to both improve the herbicidal action and reduce environmental toxicity. PHB or PHBV microparticles containing ametryn were prepared and the efficiencies of herbicide association and loading were evaluated, presenting similar values of approximately 40%. The microparticles were characterized by scanning electron microscopy (SEM), which showed that the average sizes of the PHB and PHBV microparticles were 5.92 ± 0.74 μm and 5.63 ± 0.68 μm, respectively. The ametryn release profile was modified when it was encapsulated in the microparticles, with slower and more sustained release compared to the release profile of pure ametryn. When ametryn was associated with the PHB and PHBV microparticles, the amount of herbicide released in the same period of time was significantly reduced, declining to 75% and 87%, respectively. For both types of microparticle (PHB and PHBV) the release of ametryn was by diffusion processes due to anomalous transport (governed by diffusion and relaxation of the polymer chains), which did not follow Fick's laws of diffusion. The results presented in this paper are promising, in view of the successful encapsulation of ametryn in PHB or PHBV polymer microparticles, and indications that this system may help reduce the impacts caused by the herbicide, making it an environmentally safer alternative.

  4. A computerized system for control and management of radionuclide inventory: application in nuclear medicine

    International Nuclear Information System (INIS)

    Hoory, S.; Levy, I.M.; Moskowitz, G.; Bandyopadhyay, D.; Vaugeois, J.C.

    1982-01-01

    An interactive computerized system for radioisotope management and instantaneous inventory is reported. The system is capable of handling operations such as filing, nuclear imaging and disposing of various radionuclides. All radiopharmaceutical transactions are achieved with the aid of a Prime 300 mini-computer of 192K words of high speed semi-conductor memory and over 120 mega bytes of disk storage. The system automatically corrects for the appropriate decay, monitors and updates the storage file after every subsequent study. The performed study is recorded in a special file, together with the time and data retrieved from the computer's real time clock at the time of the entry. The system provides an organized and complete bookkeeping of all records concerning radionuclide transactions. It is found to be simple, efficient, highly versatile, and drastically reduces the time of operation and errors in handling the radioisotope inventory. (author)

  5. Radionuclide cardiography in medical practice

    International Nuclear Information System (INIS)

    Strangfeld, D.; Mohnike, W.; Schmidt, J.; Heine, H.; Correns, H.J.

    1986-01-01

    This publication is a compendium on all aspects of radionuclide diagnostics concerning cardiovascular system diseases. Starting with introductory remarks on the control of cardiovascular diseases the contribution of radionuclide cardiology to functional cardiovascular diagnostics as well as pathophysiological and pathobiochemical aspects of radiocardiography are outlined. Radiopharmaceuticals used in radiocardiography, physical and technical problems in application of radionuclides and their measuring techniques are discussed. In individual chapters radionuclide ventriculography, myocardial scintiscanning, circulatory diagnostics, radionuclide diagnostics of arterial hypertension, of thrombosis and in vitro diagnostics of thrombophilia are treated in the framework of clinical medicine

  6. A REVIEW ON CONTROLLED DRUG RELEASE FORMULATION: SPANSULES

    OpenAIRE

    Rinky Maurya; Dr. Pramod Kumar Sharma; Rishabha Malviya

    2014-01-01

    Spansules are a dosage form which was considered as one of the Advanced Drug Delivery System. Multidrug preparations can be delivered easily by spansules or granules in capsule technology. This type of delivery system designed to release a drug or a medicament at two or more different rates or in different span of time. A quick/slow release system provides an initial release of drug followed by a constant rate of drug release over a extended period or a defined period of time and in slow/quic...

  7. Interaction of radionuclides in severe accident conditions

    International Nuclear Information System (INIS)

    Nagrale, Dhanesh B.; Bera, Subrata; Deo, Anuj Kumar; Paul, U.K.; Prasad, M.; Gaikwad, A.J.

    2015-01-01

    Nuclear power plants are designed with inherent engineering safety systems and associated operational procedures that provide an in-depth defence against accidents. Radionuclides such as Iodine, Cesium, Tellurium, Barium, Strontium, Rubidium, Molybdenum and many others may get released during a severe accident. Among these, Iodine, one of the fission products, behaviour is significant for the analysis of severe accident consequences because iodine is a chemically more active to the potential components released to the environment. During severe accident, Iodine is released and transported in aqueous, organic and inorganic forms. Iodine release from fuel, iodine transport in primary coolant system, containment, and reaction with control rods are some of the important phases in a severe accident scenario. The behaviour of iodine is governed by aerosol physics, depletion mechanisms gravitational settling, diffusiophoresis and thermophoresis. The presence of gaseous organic compounds and oxidizing compounds on iodine, reactions of aerosol iodine with boron and formation of cesium iodide which results in more volatile iodine release in containment play significant roles. Water radiolysis products due to presence of dissolved impurities, chloride ions, organic impurities should be considered while calculating iodine release. Containment filtered venting system (CFVS) consists of venturi scrubber and a scrubber tank which is dosed with NaOH and NaS_2O_3 in water where iodine will react with the chemicals and convert into NaI and Na_2SO_4. This paper elaborates the issues with respect to interaction of radionuclides and its consideration in modeling of severe accident. (author)

  8. Radionuclide Retention in Concrete Wasteforms

    Energy Technology Data Exchange (ETDEWEB)

    Bovaird, Chase C.; Jansik, Danielle P.; Wellman, Dawn M.; Wood, Marcus I.

    2011-09-30

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. The information present in the report provides data that (1) measures the effect of concrete wasteform properties likely to influence radionuclide migration; and (2) quantifies the rate of carbonation of concrete materials in a simulated vadose zone repository.

  9. Controlled release of diuron from an alginate-bentonite formulation: water release kinetics and soil mobility study.

    Science.gov (United States)

    Fernández-Pérez, M; Villafranca-Sánchez, M; González-Pradas, E; Flores-Céspedes, F

    1999-02-01

    The herbicide diuron was incorporated in alginate-based granules to obtain controlled release (CR) properties. The standard formulation (alginate-herbicide-water) was modified by the addition of different sorbents. The effect on diuron release rate caused by incorporation of natural and acid-treated bentonites in alginate formulation was studied by immersion of the granules in water under static conditions. The release of diuron was diffusion-controlled. The time taken for 50% release of active ingredient to be released into water, T(50), was calculated for the comparison of formulations. The addition of bentonite to the alginate-based formulation produced the higher T(50) values, indicating slower release of the diuron. The mobility of technical and formulated diuron was compared by using soil columns. The use of alginate-based CR formulations containing bentonite produced a less vertical distribution of the active ingredient as compared to the technical product and commercial formulation. Sorption capacities of the various soil constituents for diuron were also determined using batch experiments.

  10. Radiation curing of intelligent coating for controlled release and permeation

    International Nuclear Information System (INIS)

    Nakayama, Hiroshi; Kaetsu, Isao; Uchida, Kumao; Sakata, Shoei; Tougou, Kazuhide; Hara, Takamichi; Matsubara, Yoshio

    2002-01-01

    Intelligent membranes for pH and temperature-responsive drug releases were developed by coating and curing of polymer-drug composite film with electrolyte or N-isopropyl acrylamide curable mixture. It was proved that those intelligent membranes showed the stimule-sensitive and responsive release functions and could be produced efficiently by radiation curing processing with a conveyer system

  11. Formulation and Pharmacokinetic Evaluation of Controlled-Release ...

    African Journals Online (AJOL)

    A coating layer was then applied with a mixture of HPMC, ethylcellulose, shellac, and HPMC phthalate. The effect of several formulation variables on in vitro drug release was studied; furthermore, the drug release kinetics of the optimized formulation was evaluated. The in vivo pharmacokinetics of the optimized formulation ...

  12. Formulation and Pharmacokinetic Evaluation of Controlled-Release ...

    African Journals Online (AJOL)

    The effect of several formulation variables on in ... The in vivo pharmacokinetics of the optimized formulation was compared ... Results: The core tablets exhibited extended release consisting of drug release from the embedded ... important factor in medical treatment with respect ... The solvents for high-performance liquid.

  13. Controlled release of free-falling test models

    Science.gov (United States)

    Fife, W. J.; Holway, H. P.

    1970-01-01

    Releasing device, powered by a drill motor through an adjustable speed reducer, has a spinning release head with three retractable spring-loaded fingers. The fingers are retracted by manual triggering of a cable at the motor end of the unit.

  14. PH-triggered micellar membrane for controlled release microchips

    KAUST Repository

    Yang, Xiaoqiang

    2011-01-01

    A pH-responsive membrane based on polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) block copolymer was developed on a model glass microchip as a promising controlled polymer delivery system. The PS-b-P4VP copolymer assembles into spherical and/or worm-like micelles with styrene block cores and pyridine coronas in selective solvents. The self-assembled worm-like morphology exhibited pH-responsive behaviour due to the protonation of the P4VP block at low pH and it\\'s deprotonation at high pH and thus constituting a switchable "off/on" system. Doxorubicin (Dox) was used as cargo to test the PS-b-P4VP membrane. Luminescence experiments indicated that the membrane was able to store Dox molecules within its micellar structure at neutral pH and then release them as soon as the pH was raised to 8.0. The performance of the cast membrane was predictable and most importantly reproducible. The physiochemical and biological properties were also investigated carefully in terms of morphology, cell viability and cell uptake. This journal is © The Royal Society of Chemistry.

  15. Radionuclide cisternography

    International Nuclear Information System (INIS)

    Song, H.H.

    1980-01-01

    The purpose of this thesis is to show that radionuclide cisternography makes an essential contribution to the investigation of cerebrospinal fluid (CSF) dynamics, especially for the investigation of hydrocephalus. The technical details of radionuclide cisternography are discussed, followed by a description of the normal and abnormal radionuclide cisternograms. The dynamics of CFS by means of radionuclide cisternography were examined in 188 patients in whom some kind of hydrocephalus was suspected. This study included findings of anomalies associated with hydrocephalus in a number of cases, such as nasal liquorrhea, hygromas, leptomeningeal or porencephalic cysts. The investigation substantiates the value of radionuclide cisternography in the diagnosis of disturbances of CSF flow. The retrograde flow of radiopharmaceutical into the ventricular system (ventricular reflux) is an abnormal phenomenon indicating the presence of communicating hydrocephalus. (Auth.)

  16. Improving the control of systematic uncertainties in precision measurements of radionuclide half-life

    International Nuclear Information System (INIS)

    Towers, S.

    2013-01-01

    Many experiments designed to precisely determine the half-life of a radionuclide employ a long lived reference source to help determine the impact on the data of any systematic variation in the detector and associated electronics. The half-life of the radionuclide of interest is determined from the ratio of its decay rate data to the decay rate data from the reference source. This correction procedure assumes that any underlying systematic affects the data and reference measurements in exactly the same way. In this paper we show that when some systematic effects affect the two differently, the ratio procedure can leave artifacts in the corrected data that can compromise an unbiased and precise assessment of the radionuclide half-life. We describe two methods that can help overcome this problem. We also describe several statistical tests that help determine which effects may underlie systematic variations in the data. We discuss an illustrative example based on previously published 32 Si and 36 Cl data recorded by an experiment at Brookhaven National Laboratory. We correct the data for systematic variation related to climate variation and estimate the 32 Si half-life to be T 1/2 =171.8±1.8. The reduction in uncertainty in the 32 Si half-life, relative to the previous estimate based upon this data, is equivalent to that which would be achieved through increasing the size of the data set by almost 3.5 times. - Author-Highlights: • Isotope decay data and reference source data can have differing systematics. • Differing systematics can inflate uncertainty of isotope half-life estimate. • We describe two methods to overcome this problem. • We describe statistical tests to determine which variables cause systematics. • We analyze Brookhaven 32Si/36Cl decay data as an illustrative example

  17. Determination of radionuclides. Fingerprint determination on protection clothing from the controlled areas in nuclear facilities

    International Nuclear Information System (INIS)

    Scholand, Soeren

    2014-01-01

    ENS (Euro Nuclear Services) in Coevorden, Netherlands, is decontaminating und providing protection clothing for the personnel in nuclear facilities. The capacity of the laundry is about 750 kg/h. The clean laundry section is cleaning non-contaminated or very low contaminated articles, i.e. socks or underwear. Fingerprint is defined as the activity of certain radionuclides that differs in the different nuclear facilities. For the reception inspection the dose rate measured with scintillation detectors is compared with the customer specific fingerprint. The total activity is usually 2000 Bq/g. The dose rate limit is 0.3 mSv/h.

  18. Control of anoplophora glabripennis by releasing sterile insects

    International Nuclear Information System (INIS)

    Liu Xiaohui; Li Yongjun; Zhang Shuyong; Wang Endong; Lu Daguang

    2003-01-01

    An experiment to evaluate the effect of released sterile insects on reproduction of natural A. glabripennis population was conducted at a 30-hectare poplar tree forest in Ying County of Shanxi Province from July 10 to August 29, 2001. Though the releasing ratio was only about 2-5, results from different methods showed that the reproduction of natural A. glabripennis population was suppressed effectively by releasing sterile insects, and that hatch ratio of eggs laid by parent generation was about 20% and survival ratio of F1 progeny about 27%. (authors)

  19. Predictive property models for use in design of controlled release of pesticides

    DEFF Research Database (Denmark)

    Suné, Nuria Muro; Gani, Rafiqul; Bell, G.

    2005-01-01

    A model capable of predicting the release of an Active Ingredient (AI) from a specific device would be very useful in the field of pesticide controlled release technology for design purposes. For the release of an AI from a microcapsule a mathematical model is briefly presented here, as an introd...

  20. CONTROLLED-RELEASE OF PARACETAMOL FROM AMYLODEXTRIN TABLETS - IN-VITRO AND IN-VIVO RESULTS

    NARCIS (Netherlands)

    VANDERVEEN, J; EISSENS, AC; LERK, CF

    Amylodextrin is a suitable excipient for the design of solid controlled-release systems. The release of paracetamol from tablets containing 30% drug and 70% amylodextrin was studied in vitro and in vivo. In vitro dissolution profiles showed almost-constant drug release rates during 8 hr, when

  1. Development of controlled release spheroids using Buchananiacochinchinesis gum

    Directory of Open Access Journals (Sweden)

    Narayan Babulal Gaikwad

    2013-03-01

    Full Text Available Chirauli nut gum was isolated from the bark of Buchanania cochinchinesis (fam. Anacadiacea and was used as a release modifier for the preparation of Diclofenac sodium spheroids using the extrusion spheronization technique. The process was studied for the effects on variables when making spheroids with satisfactory particle shape, size and size distribution. The prepared spheroids were characterized for surface morphology, qualitative surface porosity, friability, bulk density and flow properties. In vitro studies demonstrated that the release exhibited Fickian diffusion kinetics which was confirmed by the Higuchi and the Korsmeyer-Peppas models. The physico-chemical parameters of the gum could be correlated to the in vitro dissolution profile of the spheroids. The spheroids were not able to sustain the drug releases over 12 hours. A greater concentration of Chirauli nut gum and a process that can accommodate such greater concentrations may produce a formulation capable of significant sustained release.

  2. Materials for Pharmaceutical Dosage Forms: Molecular Pharmaceutics and Controlled Release Drug Delivery Aspects

    Directory of Open Access Journals (Sweden)

    Patrick P. DeLuca

    2010-09-01

    Full Text Available Controlled release delivery is available for many routes of administration and offers many advantages (as microparticles and nanoparticles over immediate release delivery. These advantages include reduced dosing frequency, better therapeutic control, fewer side effects, and, consequently, these dosage forms are well accepted by patients. Advances in polymer material science, particle engineering design, manufacture, and nanotechnology have led the way to the introduction of several marketed controlled release products and several more are in pre-clinical and clinical development.

  3. Calculated concentrations of any radionuclide deposited on the ground by release from underground nuclear detonations, tests of nuclear rockets, and tests of nuclear ramjet engines

    International Nuclear Information System (INIS)

    Hicks, H.G.

    1981-11-01

    This report presents calculated gamma radiation exposure rates and ground deposition of related radionuclides resulting from three types of event that deposited detectable radioactivity outside the Nevada Test Site complex, namely, underground nuclear detonations, tests of nuclear rocket engines and tests of nuclear ramjet engines

  4. Factors controlling alkali salt deposition in recovery boilers. Release mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    McKeough, P; Kurkela, M; Kylloenen, H; Tapola, E [VTT Energy, Espoo (Finland). Process Technology Group

    1997-10-01

    The research was part of an ongoing cooperative research effort aimed at developing a model to describe the behaviour of inorganic compounds in kraft recovery boilers. During 1996 experimental investigations of sulphur release were continued. Experiments at elevated pressures and employing larger particle sizes were performed in order to gain information about mass transfer effects. The first experiments yielding data on the rates of the sulphur-release reactions were performed. This data will be used as the basis of a drop model for sulphur release being developed in cooperation with another research group. The other part of the work during 1996 explored the possibility of using chemical equilibrium calculations to predict the release of sodium, potassium and chlorine in the recovery furnace. The approach is essentially different from that employed in earlier studies in that the effects of fume formation are taken into account. So far, the predictions of the chemical equilibrium release model have, in no way, conflicted with field measurements. (orig.)

  5. Desktop 3D printing of controlled release pharmaceutical bilayer tablets.

    Science.gov (United States)

    Khaled, Shaban A; Burley, Jonathan C; Alexander, Morgan R; Roberts, Clive J

    2014-01-30

    Three dimensional (3D) printing was used as a novel medicine formulation technique for production of viable tablets capable of satisfying regulatory tests and matching the release of standard commercial tablets. Hydroxypropyl methylcellulose (HPMC 2208) (Methocel™ K100M Premium) and poly(acrylic acid) (PAA) (Carbopol(®) 974P NF) were used as a hydrophilic matrix for a sustained release (SR) layer. Hypromellose(®) (HPMC 2910) was used as a binder while microcrystalline cellulose (MCC) (Pharmacel(®) 102) and sodium starch glycolate (SSG) (Primojel(®)) were used as disintegrants for an immediate release (IR) layer. Commercial guaifenesin bi-layer tablets (GBT) were used as a model drug (Mucinex(®)) for this study. There was a favourable comparison of release of the active guaifenesin from the printed hydrophilic matrix compared with the commercially available GBT. The printed formulations were also evaluated for physical and mechanical properties such as weight variation, friability, hardness and thickness as a comparison to the commercial tablet and were within acceptable range as defined by the international standards stated in the United States Pharmacopoeia (USP). All formulations (standard tablets and 3D printed tablets) showed Korsmeyer-Peppas n values between 0.27 and 0.44 which indicates Fickian diffusion drug release through a hydrated HPMC gel layer. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Radionuclide carrier

    International Nuclear Information System (INIS)

    Hartman, F.A.; Kretschmar, H.C.; Tofe, A.J.

    1978-01-01

    A physiologically acceptable particulate radionuclide carrier is described. It comprises a modified anionic starch derivative with 0.1% to 1.5% by weight of a reducing agent and 1 to 20% by weight of anionic substituents

  7. Gastrin release: Antrum microdialysis reveals a complex neural control

    DEFF Research Database (Denmark)

    Ericsson, P; Håkanson, R; Rehfeld, Jens F.

    2010-01-01

    in both serum and microdialysate. Food intake induced a 2- to 3-fold increase in serum gastrin, while gastrin in antral microdialysate increased 10- to 15-fold. In unilaterally vagotomized rats (fasted, 3 days post-op.), food evoked a prompt peak gastrin release followed by a gradual decline on the intact......We used microdialysis to monitor local gastrin release in response to food, acid blockade and acute vagal excitation. For the first time, gastrin release has been monitored continuously in intact conscious rats in a physiologically relevant experimental setting in a fashion that minimizes...... in serum regardless of the prandial state. The rats were conscious during microdialysis except when subjected to electrical vagal stimulation. Acid blockade (omeprazole treatment of freely fed rats for 4 days), or bilateral sectioning of the abdominal vagal trunks (fasted, 3 days post-op.), raised...

  8. Controlled release fertilizers using superabsorbent hydrogel prepared by gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Elbarbary, Ahmed M.; Ghobashy, Mohamed Mohamady [Atomic Energy Authority, Nasr City (Egypt). National Center for Radiation Research and Technology (NCRTT)

    2017-07-01

    Superabsorbent hydrogels (PVP/CMC) based on polyvinylpyrrolidone (PVP)/carboxylmethyl cellulose (CMC) of different copolymer compositions were prepared by gamma radiation. Factors affecting the gel content (%) and the swelling ratio (g/g) of hydrogel such as irradiation dose as well as copolymer composition were investigated. With increasing the CMC content in PVP/CMC hydrogels, increases the swelling and improves the water retention capability. The high swelling ratio was observed at copolymer composition of PVP/CMC (60/40). Fast swelling of the hydrogels was obtained after 20 min. The effect of different fertilizers and buffers of different pH's on equilibrium swelling of hydrogels was investigated. Fertilizers such as urea, monopotassium-phosphate (MPK), and nitrogen-phosphate-potassium (NPK) were loaded onto the hydrogel to supply nitrogen, potassium and phosphorous nutrients. PVP/CMC hydrogels retained 28-36% after 72 h and slow retention was noticed up to 9 days. The swelling of hydrogel in fertilizer solutions is lower than that in water. The hydrogels showed adsorption desorption of fertilizers which governs by slow release property. The release rate of urea is much higher 10 times than that of phosphate. After 3 days, urea released 60%, while phosphate released 10-12%. The applicability of PVP/CMC hydrogels in the agricultural fields shows greater growth effect on zea maize plants. The growth of zea maize plant in soil mixed with PVP/CMC hydrogels loaded fertilizers is greater than untreated soil. The slow release fertilize, the high swelling and the slow water retention behaviors of PVP/CMC hydrogels encourage their use as safer release systems for fertilizers and as soil conditioner in agricultural applications.

  9. Controlled release fertilizers using superabsorbent hydrogel prepared by gamma radiation

    International Nuclear Information System (INIS)

    Elbarbary, Ahmed M.; Ghobashy, Mohamed Mohamady

    2017-01-01

    Superabsorbent hydrogels (PVP/CMC) based on polyvinylpyrrolidone (PVP)/carboxylmethyl cellulose (CMC) of different copolymer compositions were prepared by gamma radiation. Factors affecting the gel content (%) and the swelling ratio (g/g) of hydrogel such as irradiation dose as well as copolymer composition were investigated. With increasing the CMC content in PVP/CMC hydrogels, increases the swelling and improves the water retention capability. The high swelling ratio was observed at copolymer composition of PVP/CMC (60/40). Fast swelling of the hydrogels was obtained after 20 min. The effect of different fertilizers and buffers of different pH's on equilibrium swelling of hydrogels was investigated. Fertilizers such as urea, monopotassium-phosphate (MPK), and nitrogen-phosphate-potassium (NPK) were loaded onto the hydrogel to supply nitrogen, potassium and phosphorous nutrients. PVP/CMC hydrogels retained 28-36% after 72 h and slow retention was noticed up to 9 days. The swelling of hydrogel in fertilizer solutions is lower than that in water. The hydrogels showed adsorption desorption of fertilizers which governs by slow release property. The release rate of urea is much higher 10 times than that of phosphate. After 3 days, urea released 60%, while phosphate released 10-12%. The applicability of PVP/CMC hydrogels in the agricultural fields shows greater growth effect on zea maize plants. The growth of zea maize plant in soil mixed with PVP/CMC hydrogels loaded fertilizers is greater than untreated soil. The slow release fertilize, the high swelling and the slow water retention behaviors of PVP/CMC hydrogels encourage their use as safer release systems for fertilizers and as soil conditioner in agricultural applications.

  10. Model-based computer-aided design for controlled release of pesticides

    DEFF Research Database (Denmark)

    Muro Sunè, Nuria; Gani, Rafiqul; Bell, G.

    2005-01-01

    In the field of controlled release technology for pesticides or active ingredients (AI), models that can predict its delivery during application are important for purposes of design and marketing of the pesticide product. Appropriate models for the controlled release of pesticides, if available, ...... extended models have been developed and implemented into a computer-aided system. The total model consisting of the property models embedded into the release models are then employed to study the release of different combinations of AIs and polymer-based microcapsules.......In the field of controlled release technology for pesticides or active ingredients (AI), models that can predict its delivery during application are important for purposes of design and marketing of the pesticide product. Appropriate models for the controlled release of pesticides, if available...

  11. Complete release from regulatory control via the density of radioactive contamination of soil of the Chornobyl exclusion zone

    International Nuclear Information System (INIS)

    Bondarenko, Oleg; Fadeev, Mykhaylo; Kireev, Serhiy; Proskura, Mykola

    2008-01-01

    Full text: In this work a general procedure of establishment the criterion of complete release from regulatory control via the density of radioactive contamination of soil of alone areas of the Chornobyl exclusion zone is represented by the following three stages, namely: 1) Justification of the dose criterion of complete release by applying the fundamental approaches of regulating the prolonged exposure of the public on a basement of ICRP Publication No. 82; 2) Justification of a procedure for establishment of dose constraint through evaluation of the statistical distribution of a controlled radiation value through determination of the high boundary of the confidence interval; 3) Generalization of conversion coefficients (via the density of radioactive contamination of soil) and coverage coefficients for the dose forming factors of the public (inhalation intake of transuranium radionuclides both at natural and technogenic dust resuspension, peroral intake of 137 Cs and 90 Sr via food stuff, external exposure from 137 Cs); on a basis of these coefficients average doses and dose constraint of a critical group of the public are calculated. As it is shown in the work, the generalized criterion of complete release from regulatory control via the density of radioactive contamination of soil of the Chornobyl exclusion zone can be defined by dividing the recommended ICRP dose clearance level for situation of the post-accidental prolonged exposure of a critical group of the public, namely, 0.3 mSv·year -1 to the dose conversion coefficient (i.e. transfer from the superficial soil contamination of radioactivity to the dose constraint for the Chornobyl exclusion zone), namely, 12.9 μSv·year -1 /((kBq·M -2 ). Thus, a level of the density of radioactive contamination of soil, that provides the complete release from regulatory control makes 23.3 kBq·M -2 . For completion of the work on justification of the criterion of complete territory release in the conditions of

  12. Radionuclide co-precipitation

    International Nuclear Information System (INIS)

    Bruno, J.; Sandino, A.

    1987-12-01

    The thermodynamic and kinetic behaviour of the minor components of the spent fuel matrix has been theoretically and experimentally investigated. Two different situations have been studied: Part I, the near field scenario, where the release and migration of the minor components is dependent on the solubility behaviour of UO 2 (s); Part II, the far field, where the solubility and transport of the radionuclides is related to the major geochemical processes occurring. (orig.)

  13. Controlled Release Formulation of Indomethacin Prepared With Bee ...

    African Journals Online (AJOL)

    Abstract. Purpose: To prepare and evaluate new sustained release formulations of indomethacin based on extracts of propolis (bee glue). Methods: Standardization of propolis (bee glue) extracts was performed by high performance liquid chromatography (HPLC) and determination of the values of fat and fixed oils. Several ...

  14. Controlling benthic release of phosphorus in different Baltic Sea scales

    DEFF Research Database (Denmark)

    Pitkänen, Heikki; Bendtsen, Jørgen; Hansen, Jørgen L. S.

    The general aim of the PROPPEN project was to study whether it is possible to counteract near-bottom anoxia and excess benthic nutrient release ("internal loading") in the Baltic Sea by artificial oxygenation in cost-efficient and socio-economically beneficial ways. Two pilot sites were selected ...

  15. Biodegradable hollow fibres for the controlled release of drugs

    NARCIS (Netherlands)

    Schakenraad, J.M.; Oosterbaan, J.A.; Nieuwenhuis, P.; Molenaar, I.; Olijslager, J.; Potman, W.; Eenink, M.J.D.; Feijen, Jan

    1988-01-01

    Biodegradable hollow fibres of poly-l-lactic acid (PLLA) filled with a suspension of the contraceptive hormone levonorgestrel in castor oil were implanted subcutaneously in rats to study the rate of drug release, rate of biodegradation and tissue reaction caused by the implant. The in vivo drug

  16. Characterization of a Planetary Boundary Layer model to evaluate radionuclides releases in nuclear installations; Caracterizacao de um modelo de camada limite planetaria para avaliar liberacoes de radionuclideos em instalacoes nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Molnary, Leslie de

    1993-07-01

    A two layer bulk model is used to simulate numerically the time and spatial evolution of concentration of radionuclides in the Planetary Boundary Layer (PBL) for convective and stable conditions. In this model, the closure hypothesis are based on the integrated version of the Turbulent Kinetics Energy (TKE) equation (Smeda,1979). This type of model was adopted here because it is numerically simple to be applied operationally in routine and emergency support systems of atmospheric releases at nuclear power plants, and the hypothesis of the efficiency of the vertical mixing seems to be physically reasonable to simulated PBL evolution for high wind conditions and stable conditions in Subtropical latitudes regions. In order to validate the model to the nuclear power plants of the Centro Experimental Aramar (CEA), located in Ipero, State of Sao Paulo, Brazil, numerical simulations were carried out with initial and boundary conditions based on vertical profiles of temperature and horizontal wind speed and direction obtained from tethered balloon soundings, synoptic charts at 850 hPa and surface observations. Comparisons between a 24 hour long numerical simulation and observations indicate that the model is capable of reproduce the diurnal evolution of temperature and horizontal wind during the convective regime. During stable conditions, the slab model was able to simulate the intensity of the surface inversion as a difference between the mixed layer and surface temperatures. The simulated mixed layer height matches with observations during the convective and stable regime. A daytime release of radionuclides was simulated for CEA region and the results indicated that the maximum relative concentration reaches a distance about 15 Km in 1 hour, varing from 100 times background at the moment of the release to 15 times the background. For night releases, the maximum concentration reaches the same distance in 45 minutes, varing from 100 to 30 times the background values

  17. Estimates of internal dose equivalent to 22 target organs for radionuclides occurring in routine releases from nuclear fuel-cycle facilities. Vol. 1

    International Nuclear Information System (INIS)

    Killough, G.G.; Dunning, D.E. Jr.; Bernard, S.R.; Pleasant, J.C.

    1978-01-01

    This report is the first of a two-volume tabulation of internal radiation dose conversion factors for man for radionuclides of interest in environmental assessments of light-water-reactor fuel cycles. This volume treats 68 radionuclides, all of mass number less than 150. Intake by inhalation and ingestion is considered. In the former case, the ICRP Task Group Lung Model has been used to simulate the behavior of particulate matter in the respiratory tract. Results corresponding to activity median aerodynamic diameters (AMAD) of 0.3, 1.0, and 5.0 μm are given. The GI tract has been represented by a four-segment catenary model with exponential transfer of radioactivity from one segment to the next. Retention of radionuclides in other organs was characterized by linear combinations of decaying exponential functions. Dose equivalent per microcurie intake of each parent nuclide is given for 22 target organs with contributions from specified source organs plus surplus activity in the rest of the body. Cross irradiation due to penetrating radiations has also been considered in the calculations

  18. 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)

  19. [Preparation, quality control and thyroid molecule imaging of solid-target based radionuclide ioine-124].

    Science.gov (United States)

    Zhu, H; Wang, F; Guo, X Y; Li, L Q; Duan, D B; Liu, Z B; Yang, Z

    2018-04-18

    To provide useful information for the further production and application of this novel radio-nuclide for potential clinical application. 124 Te (p,n) 124 I nuclide reaction was used for the 124 I production. Firstly, the target material, 124 TeO 2 (200 mg) and Al2O3 (30 mg) mixture, were compressed into the round platinum based solid target by tablet device. HM-20 medical cyclotron was applied to irradiate the solid target slice for 6-10 h with helium and water cooling. Then, the radiated solid target was placed for 12 h (overnight) to decay the radioactive impurity; finally, 124 I was be purified by dry distillation using 1 mL/min nitrogen for about 6 hours and radiochemical separation methods. Micro-PET imaging studies were performed to investigate the metabolism properties and thyroid imaging ability of 124 I.After 740 kBq 124 I was injected intravenously into the tail vein of the normal mice, the animals were imaged with micro-PET and infused with CT. The micro-PET/CT infusion imaging revealed actual state 124 I's metabolism in the mice. It was been successfully applied for 200 mg 124 TeO 2 plating by the tablet device on the surface of platinum. It showed smooth, dense surface and without obviously pits and cracks. The enriched 124 Te target was irradiated for 6 to 10 hours at about 12.0 MeV with 20 μA current on HM-20 cyclotron. Then 370-1 110 MBq 124 I could be produced on the solid target after irradiation and 370-740 MBq high specific activity could be collected afterdry distillation separation and radio-chemical purification. 124 I product was finally dissolved in 0.01 mol/L NaOH for the future distribution. The gamma spectrum of the produced 124 I-solution showed that radionuclide purity was over 80.0%. The micro-PET imaging of 124 I in the normal mice exhibited the thyroid and stomach accumulations and kidney metabolism, the bladder could also be clearly visible, which was in accordance with what was previously reported. To the best of our knowledge

  20. Effect of Nisin's Controlled Release on Microbial Growth as Modeled for Micrococcus luteus.

    Science.gov (United States)

    Balasubramanian, Aishwarya; Lee, Dong Sun; Chikindas, Michael L; Yam, Kit L

    2011-06-01

    The need for safe food products has motivated food scientists and industry to find novel technologies for antimicrobial delivery for improving food safety and quality. Controlled release packaging is a novel technology that uses the package to deliver antimicrobials in a controlled manner and sustain antimicrobial stress on the targeted microorganism over the required shelf life. This work studied the effect of controlled release of nisin to inhibit growth of Micrococcus luteus (a model microorganism) using a computerized syringe pump system to mimic the release of nisin from packaging films which was characterized by an initially fast rate and a slower rate as time progressed. The results show that controlled release of nisin was strikingly more effective than instantly added ("formulated") nisin. While instant addition experiments achieved microbial inhibition only at the beginning, controlled release experiments achieved complete microbial inhibition for a longer time, even when as little as 15% of the amount of nisin was used as compared to instant addition.

  1. Application of tumbling melt granulation (TMG) method to prepare controlled-release fine granules.

    Science.gov (United States)

    Maejima, T; Kubo, M; Osawa, T; Nakajima, K; Kobayashi, M

    1998-03-01

    The tumbling melt granulation (TMG) method was applied to prepare controlled-release fine granules of diltiazem hydrochloride (DH). The entire process, from the preparation of the cores by the adherence of DH to the sucrose crystal to the subsequent coating of the controlled-release layer, was performed without using any solvent. A mixture of meltable material, talc, and ethylcellulose was used for the controlled-release layer and controlled-release fine granules approximately 400 microns in diameter were obtained with excellent producibility. The dissolution rate of DH from these fine granules was similar to that of a once-a-day dosage form obtained in the market; further, the dependency of the dissolution profile on pH of the media was less. Thus, it was concluded that this TMG method was very useful for preparing not only controlled-release beads of granule size (usually 500 to 1400 microns) but also fine granules.

  2. Acoustically Triggered Disassembly of Multilayered Polyelectrolyte Thin Films through Gigahertz Resonators for Controlled Drug Release Applications

    Directory of Open Access Journals (Sweden)

    Zhixin Zhang

    2016-11-01

    Full Text Available Controlled drug release has a high priority for the development of modern medicine and biochemistry. To develop a versatile method for controlled release, a miniaturized acoustic gigahertz (GHz resonator is designed and fabricated which can transfer electric supply to mechanical vibrations. By contacting with liquid, the GHz resonator directly excites streaming flows and induces physical shear stress to tear the multilayered polyelectrolyte (PET thin films. Due to the ultra-high working frequency, the shear stress is greatly intensified, which results in a controlled disassembling of the PET thin films. This technique is demonstrated as an effective method to trigger and control the drug release. Both theory analysis and controlled release experiments prove the thin film destruction and the drug release.

  3. Quality control for radionuclide determinations in the Saxon state laboratories for environmental radioactivity by intercomparison and comparative measurements

    International Nuclear Information System (INIS)

    Knobus, B.

    2001-01-01

    Quality control for radionuclide analysis is necessary and essential for the quality assurance of the measuring results executing the measuring programmes of surveillance of the radioactivity in the environment and from installations. Acts, ordinances and guidelines require the participation in intercomparisons for authorized institutions detecting the demanded quality of measurements (e.g. trueness, reproducibility) for Federal Authorities. These are mainly those intercomparisons which are prepared, practised and evaluated by the federal laboratories. Comparative measurements are generally organized and executed by the state laboratory itself with a few participants for special measuring tasks. In this paper are described and discussed extend and special results of those intercomparisons and comparative measurements of the Saxon state laboratories for environmental radioactivity from 1992 until 2000. If necessary, there are following improvements for quality assurance. (orig.) [de

  4. Gastrin release: Antrum microdialysis reveals a complex neural control

    DEFF Research Database (Denmark)

    Ericsson, P; Håkanson, R; Rehfeld, Jens F.

    2010-01-01

    We used microdialysis to monitor local gastrin release in response to food, acid blockade and acute vagal excitation. For the first time, gastrin release has been monitored continuously in intact conscious rats in a physiologically relevant experimental setting in a fashion that minimizes...... in serum regardless of the prandial state. The rats were conscious during microdialysis except when subjected to electrical vagal stimulation. Acid blockade (omeprazole treatment of freely fed rats for 4 days), or bilateral sectioning of the abdominal vagal trunks (fasted, 3 days post-op.), raised...... the gastrin concentration in blood as well as microdialysate. The high gastrin concentration following omeprazole treatment was not affected by vagotomy. Vagal excitation stimulated the G cells: electrical vagal stimulation and pylorus ligation (fasted rats) raised the gastrin concentration transiently...

  5. Clearance and release from control - An international perspective

    International Nuclear Information System (INIS)

    Thierfeldt, S.

    2005-01-01

    This paper tries to give an overview of the clearance, or release from regulatory control, on an international scale, including some of those countries where clearance has become or is about to become vital for D and D. The emphasis lies on the impact of clearance, and in particular of differences between clearance levels of various countries, on D and D. Relevance of clearance for D and D of nuclear installations Clearance is an essential part of waste management (or more general, material management) in nuclear installations, and in particular during the decommissioning phase where waste streams continues to arise. Of course, the relevance of clearance in a particular country depends on a number of factors, like: availability of a final repository and its price; prevailing decommissioning strategy; number of nuclear installations reaching decommissioning phase. This small selection of reasons why clearance may be of varying importance for different countries may already suffice to illustrate why up to now clearance has been developed and implemented in quite different ways. If one thinks of additional reasons that may influence clearance, like politics, the public opinion, availability of funds etc., the situation becomes even more complex. It is, however safe to draw the conclusion that countries with a certain number of nuclear installations which have been or will soon be shut down or which are already in the decommissioning phase will need to implement provisions for clearance. This has indeed been the case with countries like the UK, Germany, the USA, Sweden, and a number of others. It is not essential for clearance levels to be exactly equal between various countries. They may differ as long as the difference is not too large, e.g. the values fall into the same order of magnitude. This is the reason why for example Germany has no problems with clearance levels which differ from the EU recommendation RP 122 partially adopted in a number of EU countries

  6. Polyoxometalate coordination induced controllable release of quinolone in hybrid film

    Science.gov (United States)

    Yang, Fan; Li, Yang; Lv, Yu-Guang; Zhou, Shu-Jing; Li, Si; Gao, Guang-Gang; Liu, Hong

    2018-05-01

    Due to some side effects of quinolones in vivo, it is an urgent issue to extend their new applications in vitro. In this paper, structure-determined vanadium-quinolone functionalized polymolybdates of (NH4)2 [(γ-Mo8O26){VO(CF)2}2] (1) and (NH4)2 [(γ-Mo8O26){VO(NF)2}2] (2) (CF = ciprofloxacin; NF = norfloxacin) have been designed and synthesized. Complex 1 or 2 features a γ-type [Mo8O26]4- polyanion functionalized by two monocapped vanadium-quinolone complexes. Different H-bonds and π···π interactions allow 1 or 2 to form a 2D layered structure at solid state. When complex 1 or 2 is transferred into polyvinyl alcohol (PVA) film, its release rate in solution is lower than that of CF- or NF-PVA film and thus forming a novel quinolone delivery system. This is the first time that slow release effect of quinolone is achieved by polyoxometalate coordination effect. The slow release of 1 or 2 in PVA film is mainly ascribed to the coordination of quinolone with polyoxometalate anions.

  7. Phenobarbital loaded microemulsion: development, kinetic release and quality control

    Directory of Open Access Journals (Sweden)

    Kayo Alves Figueiredo

    Full Text Available ABSTRACT This study aimed to obtain and characterize a microemulsion (ME containing phenobarbital (PB. The PB was incorporated in the proportion of 5% and 10% in a microemulsion system containing Labrasol(r, ethanol, isopropyl myristate and purified water. The physicochemical characterization was performed and the primary stability of the ME was evaluated. An analytical method was developed using spectrophotometry in UV = 242 nm. The kinetics of the in vitro release (Franz model of the ME and the emulsion (EM containing PB was evaluated. The incorporation of PB into ME at concentrations of 5 and 10% did not change pH and resistance to centrifugation. There was an increase in particle size, a decrease of conductivity and a change in the refractive index in relation to placebo ME. The ME remained stable in preliminary stability tests. The analytical method proved to be specific, linear, precise, accurate and robust. Regarding the kinetics of the in vitro release, ME obtained an in vitro release profile greater than the EM containing PB. Thus, the obtained ME has a potential for future transdermal application, being able to compose a drug delivery system for the treatment of epilepsy.

  8. Controlled drug release on amine functionalized spherical MCM-41

    Energy Technology Data Exchange (ETDEWEB)

    Szegedi, Agnes, E-mail: szegedi@chemres.hu [Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1025 Budapest, Pusztaszeri ut 59-67 (Hungary); Popova, Margarita; Goshev, Ivan [Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia (Bulgaria); Klebert, Szilvia [Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1025 Budapest, Pusztaszeri ut 59-67 (Hungary); Mihaly, Judit [Institute of Molecular Pharmacology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1025 Budapest, Pusztaszeri ut 59-67 (Hungary)

    2012-10-15

    MCM-41 silica with spherical morphology and small particle sizes (100 nm) was synthesized and modified by post-synthesis method with different amounts of 3-aminopropyltriethoxysilane (APTES). A comparative study of the adsorption and release of a model drug, ibuprofen, was carried out. The modified and drug loaded mesoporous materials were characterized by XRD, TEM, N{sub 2} physisorption, elemental analysis, thermal analysis and FT-IR spectroscopy. A new method was developed for the quantitative determination of amino groups in surface modified mesoporous materials by the ninhydrin reaction. Good correlation was found between the amino content of the MCM-41 materials determined by the ninhydrin method and their ibuprofen adsorption capacity. Amino modification resulted in high degree of ibuprofen loading and slow release rate in comparison to the parent non-modified MCM-41. - Graphical abstract: Determination of surface amino groups by ninhidrin method. Highlights: Black-Right-Pointing-Pointer Spherical MCM-41 modified by different amounts of APTES was studied. Black-Right-Pointing-Pointer Ibuprofen (IBU) adsorption and release characteristics was tested. Black-Right-Pointing-Pointer The ninhydrin reaction was used for the quantitative determination of amino groups. Black-Right-Pointing-Pointer Stoichiometric amount of APTES is enough for totally covering the surface with amino groups. Black-Right-Pointing-Pointer Good correlation was found between the amino content and IBU adsorption capacity.

  9. Controlled drug release on amine functionalized spherical MCM-41

    International Nuclear Information System (INIS)

    Szegedi, Agnes; Popova, Margarita; Goshev, Ivan; Klébert, Szilvia; Mihály, Judit

    2012-01-01

    MCM-41 silica with spherical morphology and small particle sizes (100 nm) was synthesized and modified by post-synthesis method with different amounts of 3-aminopropyltriethoxysilane (APTES). A comparative study of the adsorption and release of a model drug, ibuprofen, was carried out. The modified and drug loaded mesoporous materials were characterized by XRD, TEM, N 2 physisorption, elemental analysis, thermal analysis and FT-IR spectroscopy. A new method was developed for the quantitative determination of amino groups in surface modified mesoporous materials by the ninhydrin reaction. Good correlation was found between the amino content of the MCM-41 materials determined by the ninhydrin method and their ibuprofen adsorption capacity. Amino modification resulted in high degree of ibuprofen loading and slow release rate in comparison to the parent non-modified MCM-41. - Graphical abstract: Determination of surface amino groups by ninhidrin method. Highlights: ► Spherical MCM-41 modified by different amounts of APTES was studied. ► Ibuprofen (IBU) adsorption and release characteristics was tested. ► The ninhydrin reaction was used for the quantitative determination of amino groups. ► Stoichiometric amount of APTES is enough for totally covering the surface with amino groups. ► Good correlation was found between the amino content and IBU adsorption capacity.

  10. Controlled release of ibuprofen using Mg Al LDH nano carrier

    Science.gov (United States)

    Dasgupta, Sudip

    2017-08-01

    In the present study, NSAID (non-steroidal anti-inflammatory drugs) such as ibuprofen in anionic form has been intercalated in-situ into the interlayer space of Mg Al LDH nanoparticle during co-precipitation of hydroxides. LDH nanohybrids are characterized by XRD, FTIR and UV spectroscopy. Mg1-xAlx(NO3)x(OH)2.nH2O nanoparticles were synthesized using co-precipitation method from an aqueous solution of Mg(NO3)2.6H2O and Al(NO3)3.9H2O. Ibuprofen was intercalated in inter layer space of Mg-Al LDH during coprecipitation of drug LDH conjugate in nitrogen atmosphere. The nanopowders synthesised were in the size range between 25 to 90 nm with an average particle size of 55 nm. XRD analysis proved that there is an increase in d003 spacing from 7.89 Å for pristine LDH to 14.71 Å for ibuprofen intercalated LDH due to the intercalation of bigger ibuprofen molecule in the interlayer space of LDH. FTIR analysis showed hydroxyl and carbonyl stretching of ibuprofen in LDH-IBU sample confirming the intercalation of ibuprofen in the interlayer structure of LDH. The drug release study in phosphate buffer solution at pH 7.4 using UV-Vis spectroscopy demonstrated that 50 % drug molecules were released in 15 hours and more than 85 % release was achieved after 36 hours.

  11. Radionuclide data

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Chapter 8 presents tables on selected alpha, beta, gamma and x-ray emitters by increasing energy; information on specific activity for selected radionuclides; naturally occurring radionuclides; the natural decay series; and the artificially produced neptunium series. A table of alpha emitters is listed by increasing atomic number and by energy. The table of β emitters presented is useful in identifying β emitters whose energies and possibly half-lives have been determined by standard laboratory techniques. It is also a handy guide to β-emitting isotopes for applications requiring specific half-lives and/or energies. Gamma rays for radionuclides of importance to radiological assessments and radiation protection are listed by increasing energy. The energies and branching ratios are important for radionuclide determinations with gamma spectrometry detectors. This section also presents a table of x-ray energies which are useful for radiochemical analyses. A number of nuclides emit x-rays as part of their decay scheme. These x-rays may be counted with Ar proportional counters, Ge planar or n-type Ge co-axial detectors, or thin crystal NaI(T1) scintillation counters. In both cases, spectral measurements can be made and both qualitative and quantitative information obtained on the sample. Nuclear decay data (energy and probability by radiation type) for more than one hundred radionuclides that are important to health physicists are presented in a schematic manner

  12. Investigating the feasibility of temperature-controlled accelerated drug release testing for an intravaginal ring.

    Science.gov (United States)

    Externbrink, Anna; Clark, Meredith R; Friend, David R; Klein, Sandra

    2013-11-01

    The objective of the present study was to investigate if temperature can be utilized to accelerate drug release from Nuvaring®, a reservoir type intravaginal ring based on polyethylene vinyl acetate copolymer that releases a constant dose of contraceptive steroids over a duration of 3 weeks. The reciprocating holder apparatus (USP 7) was utilized to determine real-time and accelerated etonogestrel release from ring segments. It was demonstrated that drug release increased with increasing temperature which can be attributed to enhanced drug diffusion. An Arrhenius relationship of the zero-order release constants was established, indicating that temperature is a valid parameter to accelerate drug release from this dosage form and that the release mechanism is maintained under these accelerated test conditions. Accelerated release tests are particularly useful for routine quality control to assist during batch release of extended release formulations that typically release the active over several weeks, months or even years, since they can increase the product shelf life. The accelerated method should therefore be able to discriminate between formulations with different release characteristics that can result from normal manufacturing variance. In the case of Nuvaring®, it is well known that the process parameters during the extrusion process strongly influence the polymeric structure. These changes in the polymeric structure can affect the permeability which, in turn, is reflected in the release properties. Results from this study indicate that changes in the polymeric structure can lead to a different temperature dependence of the release rate, and as a consequence, the accelerated method can become less sensitive to detect changes in the release properties. When the accelerated method is utilized during batch release, it is therefore important to take this possible restriction into account and to evaluate the accelerated method with samples from non

  13. A novel and alternative approach to controlled release drug delivery system based on solid dispersion technique

    Directory of Open Access Journals (Sweden)

    Tapan Kumar Giri

    2012-12-01

    Full Text Available The solid dispersion method was originally used to improve the dissolution properties and the bioavailability of poorly water soluble drugs by dispersing them into water soluble carriers. In addition to the above, dissolution retardation through solid dispersion technique using water insoluble and water swellable polymer for the development of controlled release dosage forms has become a field of interest in recent years. Development of controlled release solid dispersion has a great advantage for bypassing the risk of a burst release of drug; since the structure of the solid dispersion is monolithic where drug molecules homogeneously disperse. Despite the remarkable potential and extensive research being conducted on controlled release solid dispersion system, commercialization and large scale production are limited. The author expects that recent technological advances may overcome the existing limitations and facilitate the commercial utilization of the techniques for manufacture of controlled release solid dispersions. This article begins with an overview of the different carriers being used for the preparation of controlled release solid dispersion and also different techniques being used for the purpose. Kinetics of drug release from these controlled release solid dispersions and the relevant mathematical modeling have also been reviewed in this manuscript.

  14. SR 97 - Radionuclide transport calculations

    Energy Technology Data Exchange (ETDEWEB)

    Lindgren, Maria [Kemakta Konsult AB, Stockholm (Sweden); Lindstroem, Fredrik [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

    1999-12-01

    values. In that case almost all radionuclides will be contained in the near field. The dose rate in the biosphere is essentially controlled by the possibilities of dilution. If the release occurs to an inner bay or open coast, the dose rates will be several orders of magnitude lower than if the release occurs to a drinking water well or peat area.

  15. SR 97 - Radionuclide transport calculations

    International Nuclear Information System (INIS)

    Lindgren, Maria; Lindstroem, Fredrik

    1999-12-01

    radionuclides will be contained in the near field. The dose rate in the biosphere is essentially controlled by the possibilities of dilution. If the release occurs to an inner bay or open coast, the dose rates will be several orders of magnitude lower than if the release occurs to a drinking water well or peat area

  16. Controlled Release Kinetics in Hydroxy Double Salts: Effect of Host Anion Structure

    Directory of Open Access Journals (Sweden)

    Stephen Majoni

    2014-01-01

    Full Text Available Nanodimensional layered metal hydroxides such as layered double hydroxides (LDHs and hydroxy double salts (HDSs can undergo anion exchange reactions releasing intercalated anions. Because of this, these metal hydroxides have found applications in controlled release delivery of bioactive species such as drugs and pesticides. In this work, isomers of hydroxycinnamate were used as model compounds to systematically explore the effects of anion structure on the rate and extent of anion release in HDSs. Following intercalation and subsequent release of the isomers, it has been demonstrated that the nature and position of substituent groups on intercalated anions have profound effects on the rate and extent of release. The extent of release was correlated with the magnitude of dipole moments while the rate of reaction showed strong dependence on the extent of hydrogen bonding within the layers. The orthoisomer showed a more sustained and complete release as compared to the other isomers.

  17. Optimization of production and quality control of therapeutic radionuclides and radiopharmaceuticals. Final report of a co-ordinated research project 1994-1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-09-01

    The `renaissance` of the therapeutic applications of radiopharmaceuticals during the last few years was in part due to a greater availability of radionuclides with appropriate nuclear decay properties, as well as to the development of carrier molecules with improved characteristics. Although radionuclides such as {sup 32}P, {sup 89}Sr and {sup 131}I, were used from the early days of nuclear medicine in the late 1930s and early 1940s, the inclusion of other particle emitting radionuclides into the nuclear medicine armamentarium was rather late. Only in the early 1980s did the specialized scientific literature start to show the potential for using other beta emitting nuclear reactor produced radionuclides such as {sup 153}Sm, {sup 166} Ho, {sup 165}Dy and {sup 186-188}Re. Bone seeking agents radiolabelled with the above mentioned beta emitting radionuclides demonstrated clear clinical potential in relieving intense bone pain resulting from metastases of the breast, prostate and lung of cancer patients. Therefore, upon the recommendation of a consultants meeting held in Vienna in 1993, the Co-ordinated Research Project (CRP) on Optimization of the Production and quality control of Radiotherapeutic Radionuclides and Radiopharmaceuticals was established in 1994. The CRP aimed at developing and improving existing laboratory protocols for the production of therapeutic radionuclides using existing nuclear research reactors including the corresponding radiolabelling, quality control procedures; and validation in experimental animals. With the participation of ten scientists from IAEA Member States, several laboratory procedures for preparation and quality control were developed, tested and assessed as potential therapeutic radiopharmaceuticals for bone pain palliation. In particular, the CRP optimised the reactor production of {sup 153}Sm and the preparation of the radiopharmaceutical {sup 153}Sm-EDTMP (ethylene diamine tetramethylene phosphonate), as well as radiolabelling

  18. Optimization of production and quality control of therapeutic radionuclides and radiopharmaceuticals. Final report of a co-ordinated research project 1994-1998

    International Nuclear Information System (INIS)

    1999-09-01

    The 'renaissance' of the therapeutic applications of radiopharmaceuticals during the last few years was in part due to a greater availability of radionuclides with appropriate nuclear decay properties, as well as to the development of carrier molecules with improved characteristics. Although radionuclides such as 32 P, 89 Sr and 131 I, were used from the early days of nuclear medicine in the late 1930s and early 1940s, the inclusion of other particle emitting radionuclides into the nuclear medicine armamentarium was rather late. Only in the early 1980s did the specialized scientific literature start to show the potential for using other beta emitting nuclear reactor produced radionuclides such as 153 Sm, 166 Ho, 165 Dy and 186-188 Re. Bone seeking agents radiolabelled with the above mentioned beta emitting radionuclides demonstrated clear clinical potential in relieving intense bone pain resulting from metastases of the breast, prostate and lung of cancer patients. Therefore, upon the recommendation of a consultants meeting held in Vienna in 1993, the Co-ordinated Research Project (CRP) on Optimization of the Production and quality control of Radiotherapeutic Radionuclides and Radiopharmaceuticals was established in 1994. The CRP aimed at developing and improving existing laboratory protocols for the production of therapeutic radionuclides using existing nuclear research reactors including the corresponding radiolabelling, quality control procedures; and validation in experimental animals. With the participation of ten scientists from IAEA Member States, several laboratory procedures for preparation and quality control were developed, tested and assessed as potential therapeutic radiopharmaceuticals for bone pain palliation. In particular, the CRP optimised the reactor production of 153 Sm and the preparation of the radiopharmaceutical 153 Sm-EDTMP (ethylene diamine tetramethylene phosphonate), as well as radiolabelling techniques and quality control methods for

  19. Report of the first research co-ordination meeting on the co-ordinated research programme: Development and selection of analytical techniques for measuring accidentally released radionuclides in environment

    International Nuclear Information System (INIS)

    2001-01-01

    The participants at the second Research Co-ordination Meeting (Vienna, 12-16 August 1991) of the CRP on 'Rapid Instrumental and Separation Methods for Monitoring Radionuclides in Food and Environmental Samples', recommended that a new CRP be established. The current CRP on 'Development and Selection of Analytical Techniques and Procedures for Measuring Accidentally Released Radionuclides in Environment' was established based on this recommendation. The objectives of this CRP are to conduct research and development on applicable methodologies for response to accidental releases, and to improve and maintain the capabilities of the network of laboratories and provide training of individuals within member states. Thus, the CRP serves as a vehicle to maintain contact within the network of laboratories, while developing and transferring analytical techniques and procedures for measuring accidentally released radioactivity. The purpose of the Research Co-ordination Meeting is to discuss the proposed research programs, the status to date and the work planned for the duration of the CRP. The meeting also provides the opportunity for the CRP participants to exchange ideas and possibly develop collaborations in their research. The members of the CRP also need to discuss issues related to the previous CRP on Rapid methods. These include: the preparation of the final report of the previous CRP, the preparation of an addendum to TRS-295 and the ultimate revision or updating of TRS-295. Finally, it is intended that the members of the CRP should discuss the mandate and scope of work of the network of analytical laboratories and the steps needed to firmly establish this network

  20. Controlled release hydrophilic matrix tablet formulations of isoniazid: design and in vitro studies.

    Science.gov (United States)

    Hiremath, Praveen S; Saha, Ranendra N

    2008-01-01

    The aim of the present investigation was to develop oral controlled release matrix tablet formulations of isoniazid using hydroxypropyl methylcellulose (HPMC) as a hydrophilic release retardant polymer and to study the influence of various formulation factors like proportion of the polymer, polymer viscosity grade, compression force, and release media on the in vitro release characteristics of the drug. The formulations were developed using wet granulation technology. The in vitro release studies were performed using US Pharmacopoeia type 1 apparatus (basket method) in 900 ml of pH 7.4 phosphate buffer at 100 rpm. The release kinetics was analyzed using Korsmeyer-Peppas model. The release profiles were also analyzed using statistical method (one-way analysis of variance) and f (2) metric values. The release profiles found to follow Higuchi's square root kinetics model irrespective of the polymer ratio and the viscosity grade used. The results in the present investigation confirm that the release rate of the drug from the HPMC matrices is highly influenced by the drug/HPMC ratio and viscosity grade of the HPMC. Also, the effect of compression force and release media was found to be significant on the release profiles of isoniazid from HPMC matrix tablets. The release mechanism was found to be anomalous non-Fickian diffusion in all the cases. In the present investigation, a series of controlled release formulations of isoniazid were developed with different release rates and duration so that these formulations could further be assessed from the in vivo bioavailability studies. The formulations were found to be stable and reproducible.

  1. Metal cation controls phosphate release in the myosin ATPase.

    Science.gov (United States)

    Ge, Jinghua; Huang, Furong; Nesmelov, Yuri E

    2017-11-01

    Myosin is an enzyme that utilizes ATP to produce a conformational change generating a force. The kinetics of the myosin reverse recovery stroke depends on the metal cation complexed with ATP. The reverse recovery stroke is slow for MgATP and fast for MnATP. The metal ion coordinates the γ phosphate of ATP in the myosin active site. It is accepted that the reverse recovery stroke is correlated with the phosphate release; therefore, magnesium "holds" phosphate tighter than manganese. Magnesium and manganese are similar ions in terms of their chemical properties and the shell complexation; hence, we propose to use these ions to study the mechanism of the phosphate release. Analysis of octahedral complexes of magnesium and manganese show that the partial charge of magnesium is higher than that of manganese and the slightly larger size of manganese ion makes its ionic potential smaller. We hypothesize that electrostatics play a role in keeping and releasing the abstracted γ phosphate in the active site, and the stronger electric charge of magnesium ion holds γ phosphate tighter. We used stable myosin-nucleotide analog complex and Raman spectroscopy to examine the effect of the metal cation on the relative position of γ phosphate analog in the active site. We found that in the manganese complex, the γ phosphate analog is 0.01 nm further away from ADP than in the magnesium complex. We conclude that the ionic potential of the metal cation plays a role in the retention of the abstracted phosphate. © 2017 The Protein Society.

  2. Application of controlled release technology to uranium mill tailings stabilization

    International Nuclear Information System (INIS)

    Burton, F.G.; Cataldo, D.A.; Cline, J.F.; Skiens, W.E.

    1981-01-01

    A trifluralin (herbicide) releasing device was developed with a theoretical effective lifetime in excess of 100 years. When placed in a layer in soil, the PCD system will prevent root penetration through that layer without harming the overlying vegetation. Equilibrium concentrations of trifluralin in soil can be adjusted (along with the theoretical life of the device) to suit specific needs. The present system was designed specifically to protect the asphalt layer or clay/aggregate barriers on uranium mill tailings piles; PCD devices composed of pellets could also be implanted over burial sites for radioactive and/or toxic materials, preventing translocation of those materials to plant shoots, and thence into the biosphere

  3. Application of Electrostatic Extrusion - Flavour Encapsulation and Controlled Release.

    Science.gov (United States)

    Manojlovic, Verica; Rajic, Nevenka; Djonlagic, Jasna; Obradovic, Bojana; Nedovic, Viktor; Bugarski, Branko

    2008-03-03

    The subject of this study was the development of flavour alginate formulationsaimed for thermally processed foods. Ethyl vanilline was used as the model flavourcompound. Electrostatic extrusion was applied for the encapsulation of ethyl vanilline inalginate gel microbeads. The obtained microbeads with approx. 10 % w/w of ethylvanilline encapsulated in about 2 % w/w alginate were uniformly sized spheres of about450 μm. Chemical characterization by H-NMR spectroscopy revealed that the alginateused in this study had a high content (67 %) of guluronic residues and was rich in GG diadblocks (FGG = 55%) and thus presented a high-quality immobilisation matrix. The thermalbehaviour of alginate beads encapsulating ethyl vanilline was investigated bythermogravimetric (TG) and differential scanning calorimetry measurements (TG-DSC)under heating conditions which mimicked usual food processing to provide informationabout thermal decomposition of alginate matrix and kinetics of aroma release. Two wellresolved weight losses were observed. The first one was in the 50-150 °C temperaturerange with the maximum at approx. 112 °C, corresponding to the dehydration of thepolymer network. The second loss in the 220-325 °C temperature range, with a maximumat ~ 247 °C corresponded to the release of vanilline. The obtained results indicate that up to230 °C most of the vanilline remained intacta, while prolonged heating at elevatedtemperatures led to the entire loss of the aroma compound.

  4. Application of Electrostatic Extrusion – Flavour Encapsulation and Controlled Release

    Science.gov (United States)

    Manojlovic, Verica; Rajic, Nevenka; Djonlagic, Jasna; Obradovic, Bojana; Nedovic, Viktor; Bugarski, Branko

    2008-01-01

    The subject of this study was the development of flavour alginate formulations aimed for thermally processed foods. Ethyl vanilline was used as the model flavour compound. Electrostatic extrusion was applied for the encapsulation of ethyl vanilline in alginate gel microbeads. The obtained microbeads with approx. 10 % w/w of ethyl vanilline encapsulated in about 2 % w/w alginate were uniformly sized spheres of about 450 μm. Chemical characterization by H-NMR spectroscopy revealed that the alginate used in this study had a high content (67 %) of guluronic residues and was rich in GG diad blocks (FGG = 55%) and thus presented a high-quality immobilisation matrix. The thermal behaviour of alginate beads encapsulating ethyl vanilline was investigated by thermogravimetric (TG) and differential scanning calorimetry measurements (TG-DSC) under heating conditions which mimicked usual food processing to provide information about thermal decomposition of alginate matrix and kinetics of aroma release. Two well resolved weight losses were observed. The first one was in the 50-150 °C temperature range with the maximum at approx. 112 °C, corresponding to the dehydration of the polymer network. The second loss in the 220-325 °C temperature range, with a maximum at ∼ 247 °C corresponded to the release of vanilline. The obtained results indicate that up to 230 °C most of the vanilline remained intacta, while prolonged heating at elevated temperatures led to the entire loss of the aroma compound. PMID:27879775

  5. Solubility limited radionuclide transport through geologic media

    International Nuclear Information System (INIS)

    Muraoka, Susumu; Iwamoto, Fumio; Pigford, T.H.

    1980-11-01

    Prior analyses for the migration of radionuclides neglect solubility limits of resolved radionuclide in geologic media. But actually some of the actinides may appear in chemical forms of very low solubility. In the present report we have proposed the migration model with no decay parents in which concentration of radionuclide is limited in concentration of solubility in ground water. In addition, the analytical solutions of the space-time-dependent concentration are presented in the case of step release, band release and exponential release. (author)

  6. Use of fibrin sealants for the localized, controlled release of cefazolin

    Science.gov (United States)

    Tredwell, Stephen; Jackson, John K.; Hamilton, Donald; Lee, Vivian; Burt, Helen M.

    2006-01-01

    Background Fibrin sealants are used increasingly in surgery to reduce bleeding and improve wound healing. They have great potential as biocompatible, biodegradable drug delivery systems, because the sealant may adhere to the target tissue and allow controlled release of the drug over an extended period. We investigated the encapsulation, stability and controlled release of erythromycin and cefazolin from Beriplast fibrin sealants (Aventis Behring Canada). Methods Drug-loaded clots were cast in glass vials and allowed to set. We observed the clots for drug precipitation and aggregation, and we assessed the effect of drug encapsulation on clot strength. Drug stability and release from the clots in phosphate buffered saline (PBS) was quantified by ultraviolet and visible violet absorbance spectroscopy and high-performance liquid chromatography. Results Erythromycin was found to release slowly from the fibrin clots over the first 2 hours but then degrade rapidly. Cefazolin was found to be very stable in clots in PBS (97% stable at 2 d and 93% stable at 5 d). The drug released in a controlled manner over 2 days, with most being released during the first day. The dose of drug released could be varied by changing the amount placed in the thrombin solution. Clot thickness had no effect on the rate of cefazolin release. Conclusion Overall, the 2-day release profile and the excellent stability of the drug suggest that cefazolin-loaded fibrin sealants may offer an effective route of postoperative antibiotic delivery. PMID:17152573

  7. Limited mobility of target pests crucially lowers controllability when sterile insect releases are spatiotemporally biased.

    Science.gov (United States)

    Ikegawa, Yusuke; Himuro, Chihiro

    2017-05-21

    The sterile insect technique (SIT) is a genetic pest control method wherein mass-reared sterile insects are periodically released into the wild, thereby impeding the successful reproduction of fertile pests. In Okinawa Prefecture, Japan, the SIT has been implemented to eradicate the West Indian sweet potato weevil Euscepes postfasciatus (Fairmaire), which is a flightless agricultural pest of sweet potatoes. It is known that E. postfasciatus is much less mobile than other insects to which the SIT has been applied. However, previous theoretical studies have rarely examined effects of low mobility of target pests and variation in the spatiotemporal evenness of sterile insect releases. To theoretically examine the effects of spatiotemporal evenness on the regional eradication of less mobile pests, we constructed a simple two-patch population model comprised of a pest and sterile insect moving between two habitats, and numerically simulated different release strategies (varying the number of released sterile insects and release intervals). We found that spatially biased releases allowed the pest to spatially escape from the sterile insect, and thus intensively lowered its controllability. However, we showed that the temporally counterbalancing spatially biased releases by swapping the number of released insects in the two habitats at every release (called temporal balancing) could greatly mitigate this negative effect and promote the controllability. We also showed that the negative effect of spatiotemporally biased releases was a result of the limited mobility of the target insect. Although directed dispersal of the insects in response to habitats of differing quality could lower the controllability in the more productive habitat, the temporal balancing could promote and eventually maximize the controllability as released insects increased. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Production and Investigation of Controlled Drug Release Properties of Tamoxifen Loaded Alginate-Gum Arabic Microbeads

    Directory of Open Access Journals (Sweden)

    Rukiye Yavaşer

    2016-08-01

    Full Text Available The entrapment of tamoxifen onto alginate-gum arabic beads and the production of controlled drug release was investigated in this study. The polymeric system that would provide the controlled release of tamoxifen was formed using alginate and gum arabic. In the first phase of the study, the optimization of the alginate-gum arabic beads production was conducted; then the study continued with drug entrapment experiments. Tamoxifen entrapment yield was found to be approximately 90% of initial tamoxifen concentration. In vitro drug release experiments were performed in simulated gastric juice and intestinal fluid where the tamoxifen release was 20% and 53% of the initial drug present, respectively. As a result of this study, it is expected that a valuable contribution to the field of controlled drug release system production is realized.

  9. Waste isolation pilot plant performance assessment: Radionuclide release sensitivity to diminished brine and gas flows to/from transuranic waste disposal areas

    Energy Technology Data Exchange (ETDEWEB)

    Day, Brad A.; Camphouse, R. C.; Zeitler, Todd R. [Sandia National Laboratories, Carlsbad (United States)

    2017-03-15

    Waste Isolation Pilot Plant repository releases are evaluated through the application of modified parameters to simulate accelerated creep closure, include capillary pressure effects on relative permeability, and increase brine and gas saturation in the operations and experimental (OPS/EXP) areas. The modifications to the repository model result in increased pressures and decreased brine saturations in waste areas and increased pressures and brine saturations in the OPS/EXP areas. Brine flows up the borehole during a hypothetical drilling intrusion are nearly identical and brine flows up the shaft are decreased. The modified parameters essentially halt the flow of gas from the southern waste areas to the northern nonwaste areas, except as transported through the marker beds and anhydrite layers. The combination of slightly increased waste region pressures and very slightly decreased brine saturations result in a modest increase in spallings and no significant effect on direct brine releases, with total releases from the Culebra and cutting and caving releases unaffected. Overall, the effects on total high-probability mean releases from the repository are insignificant, with total low-probability mean releases minimally increased. It is concluded that the modified OPS/EXP area parameters have an insignificant effect on the prediction of total releases.

  10. Core/shell PLGA microspheres with controllable in vivo release profile via rational core phase design.

    Science.gov (United States)

    Yu, Meiling; Yao, Qing; Zhang, Yan; Chen, Huilin; He, Haibing; Zhang, Yu; Yin, Tian; Tang, Xing; Xu, Hui

    2018-02-27

    Highly soluble drugs tend to release from preparations at high speeds, which make them need to be taken at frequent intervals. Additionally, some drugs need to be controlled to release in vivo at certain periods, so as to achieve therapeutic effects. Thus, the objective of this study is to design injectable microparticulate systems with controllable in vivo release profile. Biodegradable PLGA was used as the matrix material to fabricate microspheres using the traditional double emulsification-solvent evaporation method as well as improved techniques, with gel (5% gelatine or 25% F127) or LP powders as the inner phases. Their physicochemical properties were systemically investigated. Microspheres prepared by modified methods had an increase in drug loading (15.50, 16.72, 15.66%, respectively) and encapsulation efficiencies (73.46, 79.42, 74.40%, respectively) when compared with traditional methods (12.01 and 57.06%). The morphology of the particles was characterized by optical microscope (OM) and scanning electron microscopy (SEM), and the amorphous nature of the encapsulated drug was confirmed by differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis. To evaluate their release behaviour, the in vitro degradation, in vitro release and in vivo pharmacodynamics were subsequently studied. Traditional microspheres prepared in this study with water as the inner phase had a relatively short release period within 16 d when compared with modified microspheres with 5% gelatine as the inner phase, which resulted in a smooth release profile and appropriate plasma LP concentrations over 21 d. Thus this type of modified microspheres can be better used in drugs requiring sustained release. The other two formulations containing 25% F127 and LP micropowders presented two-stage release profiles, resulting in fluctuant plasma LP concentrations which may be suitable for drugs requiring controlled release. All the results suggested that drug release rates from

  11. Fabrication of ketoprofen controlled-release tablets using biopolymeric hydrophilic matrices: in-vitro studies

    International Nuclear Information System (INIS)

    Rashid, S.; Khan, B.A.; Khan, G.M.

    2017-01-01

    Ketoprofen is propionic acid derivative and belongs to the Non-Steroidal anti-inflammatory group of drugs. Due to the short half-life, dosage frequency, patient non-compliance and side effects such as gastrointestinal disturbance, peptic ulceration and gastro intest inal bleeding, it is considered to be good candidate for formulation into controlled release dosage forms. Directly compressed controlled released ( CR) tablets using Acrylic acid derivatives were prepared and evaluated. In-Vitro Physicochemical assessment of the formulated tablets were performed using different physicochemical, dimensional and quality control tests such as weight variation, thickness and diameter, hardness test, friability test, content uniformity, disintegration and dissolution testing. Results of all these tests were formed within acceptable range. The effect of carbomer polymers on the tablet characteristics, drug release rates, release patterns and release kinetics were investigated. The F2-metric technique was applied to compare dissolution profiles of ketoprofen and carbopol tablets with ketoprofen SR - tablets taken as standard preparation. Acrylic acid derivatives when used as polymers resulted in an extended release profile of about 12 h. Using Higuchi's model and the Korsmeyer equation, the drug release mechanism from the tablets was found to be an anomalous type involving diffusion and erosion. Controlled- release Ketoprofen tablets appear to be a good choice for the symptomatic treatment of rheumatoid arthritis and osteoarthritis. Convenient once-daily administration may help improve patient's compliance. (author)

  12. Releases of natural enemies in Hawaii since 1980 for classical biological control of weeds

    Science.gov (United States)

    P. Conant; J. N. Garcia; M. T. Johnson; W. T. Nagamine; C. K. Hirayama; G. P. Markin; R. L. Hill

    2013-01-01

    A comprehensive review of biological control of weeds in Hawaii was last published in 1992, covering 74 natural enemy species released from 1902 through 1980. The present review summarizes releases of 21 natural enemies targeting seven invasive weeds from 1981 to 2010. These projects were carried out by Hawaii Department of Agriculture (HDOA), USDA Forest Service (USFS...

  13. Controlled release of glaucocalyxin - a self-nanoemulsifying system from osmotic pump tablets with enhanced bioavailability.

    Science.gov (United States)

    Yanfei, Miao; Guoguang, Chen; Lili, Ren; Pingkai, Ouyang

    2017-03-01

    The purpose of this study was to develop a new formulation to enhance the bioavailability simultaneously with controlled release of glaucocalyxin A (GLA). In this study, controlled release of GLA was achieved by the osmotic release strategy taking advantage of the bioavailability enhancing capacity of self-nanoemulsifying drug delivery systems (SNEDDS). The formulation of GLA-SNEDDS was selected by the solubility and pseudoternary-phase diagrams studies. The prepared GLA-SNEDDS formulations were characterized for self-emulsification time, effect of pH and robustness to dilution, droplet size analysis and zeta potential. The optimized GLA-SNEDDS were used to prepare GLA-SNEDDS osmotic pump tablet via direct powder compression method. The effect of formulation variables on the release characteristic was investigated. GLA-SNEDDS osmotic pump tablets were administered to beagle dogs and their pharmacokinetics were compared to GLA and GLA-SNEDDS as a control. In vitro drug release studies indicated that the GLA-SNEDDS osmotic pump tablet showed sustained release profiles with 90% released within 12 h. Pharmacokinetic study showed steady blood GLA with prolonged T max and mean residence time (MRT), and enhanced bioavailability for GLA-SNEDDS osmotic pump tablet. It was concluded that simultaneous controlling on GLA release and enhanced bioavailability had been achieved by a combination of osmotic pump tablet and SNEDDS.

  14. Using polymer-coated controlled-release fertilizers in the nursery and after outplanting

    Science.gov (United States)

    Thomas D. Landis; R. Kasten Dumroese

    2009-01-01

    Controlled-release fertilizers (CRF) are the newest and most technically advanced way of supplying mineral nutrients to nursery crops. Compared to conventional fertilizers, their gradual pattern of nutrient release better meets plant needs, minimizes leaching, and therefore improves fertilizer use efficiency. In our review of the literature, we found many terms used...

  15. Radionuclide generators

    International Nuclear Information System (INIS)

    Lambrecht, R.M.; Wollongong Univ.; Tomiyoshi, K.; Sekine, T.

    1997-01-01

    The present status and future directions of research and development on radionuclide generator technology are reported. The recent interest to develop double-neutron capture reactions for production of in vivo generators; neutron rich nuclides for radio-immunotherapeutic pharmaceuticals: and advances with ultra-short lived generators is highlighted. Emphasis is focused on: production of the parent radionuclide; the selection and the evaluation of support materials and eluents with respect to the resultant radiochemical yield of the daughter, and the breakthrough of the radionuclide parent: and, the uses of radionuclide generators in radiopharmaceutical chemistry, biomedical and industrial applications. The 62 Zn → 62 Cu, 66 Ni → 66 Cu, 103m Rh → 103 Rh, 188 W → 188 Re and the 225 Ac → 221 Fr → 213 Bi generators are predicted to be emphasized for future development. Coverage of the 99 Mo → 99m Tc generator was excluded, as it the subject of another review. The literature search ended June, 1996. (orig.)

  16. Radionuclide scanning

    International Nuclear Information System (INIS)

    Shapiro, B.

    1986-01-01

    Radionuclide scanning is the production of images of normal and diseased tissues and organs by means of the gamma-ray emissions from radiopharmaceutical agents having specific distributions in the body. The gamma rays are detected at the body surface by a variety of instruments that convert the invisible rays into visible patterns representing the distribution of the radionuclide in the body. The patterns, or images, obtained can be interpreted to provide or to aid diagnoses, to follow the course of disease, and to monitor the management of various illnesses. Scanning is a sensitive technique, but its specificity may be low when interpreted alone. To be used most successfully, radionuclide scanning must be interpreted in conjunction with other techniques, such as bone radiographs with bone scans, chest radiographs with lung scans, and ultrasonic studies with thyroid scans. Interpretation is also enhanced by providing pertinent clinical information because the distribution of radiopharmaceutical agents can be altered by drugs and by various procedures besides physiologic and pathologic conditions. Discussion of the patient with the radionuclide scanning specialist prior to the study and review of the results with that specialist after the study are beneficial

  17. Models selected for calculation of doses, health effects and economic costs due to accidental radionuclide releases from nuclear power plants. Technical report

    International Nuclear Information System (INIS)

    Strenge, D.L.; Acharya, S.; Baker, D.A.; Droppo, J.G.; McPherson, R.B.

    1980-05-01

    Models are described for use in site-specific environmental consequence analysis of nuclear reactor accidents of Classes 3 through 9. The models presented relate radioactivity released to resulting doses, health effects, and costs of remedial actions. Specific models are presented for the major exposure pathways of airborne releases, waterborne releases and direct irradiation from activity within the facility buildings, such as the containment. Time-dependent atmospheric dispersion parameters, crop production parameters, and other variable parameters are used in the models. The environmental effects are analyzed for several accident start times during the year. Several remedial actions are considered

  18. Controlled release of insect sex pheromones from paraffin wax and emulsions.

    Science.gov (United States)

    Atterholt, C A; Delwiche, M J; Rice, R E; Krochta, J M

    1999-02-22

    Paraffin wax and aqueous paraffin emulsions can be used as controlled release carriers for insect sex pheromones for mating disruption of orchard pests. Paraffin can be applied at ambient temperature as an aqueous emulsion, adheres to tree bark or foliage, releases pheromone for an extended period of time, and will slowly erode from bark and biodegrade in soil. Pheromone emulsions can be applied with simple spray equipment. Pheromone release-rates from paraffin were measured in laboratory flow-cell experiments. Pheromone was trapped from an air stream with an adsorbent, eluted periodically, and quantified by gas chromatography. Pheromone release from paraffin was partition-controlled, providing a constant (zero-order) release rate. A typical paraffin emulsion consisted of 30% paraffin, 4% pheromone, 4% soy oil, 1% vitamin E, 2% emulsifier, and the balance water. Soy oil and vitamin E acted as volatility suppressants. A constant release of oriental fruit moth pheromone from paraffin emulsions was observed in the laboratory for more than 100 days at 27 degreesC, with release-rates ranging from 0.4 to 2 mg/day, depending on the concentration and surface area of the dried emulsion. The use of paraffin emulsions is a viable method for direct application of insect pheromones for mating disruption. Sprayable formulations can be designed to release insect pheromones to the environment at a rate necessary for insect control by mating disruption. At temperatures below 38 degreesC, zero-order release was observed. At 38 degreesC and higher, pheromone oxidation occurred. A partition-controlled release mechanism was supported by a zero-order pheromone release-rate, low air/wax partition coefficients, and pheromone solubility in paraffin.

  19. Control Room Habitability for Accidental Sulfuric Acid Release

    International Nuclear Information System (INIS)

    Cho, Sungmin; Lee, Heedo; Song, Dongsoo

    2006-01-01

    The 10 CFR 50 Appendix A Criterion 19, 'Control Room', requires that a control room be provided from which actions can be taken to operate the nuclear power unit safely under normal conditions and to maintain it in a safe condition under accident conditions. For compliance with the requirement, the control room of a nuclear power plant should be appropriately protected from hazardous chemicals that may be discharged as a result of equipment failures, operator errors, or events and conditions outside the control of the nuclear power plant. We have excluded sulfuric acid from a target of estimation for control room habitability merely because its boiling point is too high; qualitative analysis in this paper shows that we can exclude sulfuric acid from the target of habitability estimation

  20. Behaviour and fate radionuclides in soils. Mathematical modelling and experimental investigations

    International Nuclear Information System (INIS)

    Rovdan, E.N.

    2003-01-01

    The uncontrolled release of radionuclides as result of Chernobyl accident has led to contamination of 23% of territory of Republic of Belarus. Soil has high capacity to adsorb radionuclides and their intensive sorption provides the creation of a long-lived radionuclide source in a terrestrial environment. In the management of the contaminated areas and application of a countermeasure strategy it is extremely important to know the environmental mechanisms governing the behaviour of radionuclides in soils. Basic attention in the work is paid to the study of 137 Cs and 90 Sr because they are the main radionuclides from the view point of radioactive danger in polluted areas. The main features and processes that control radionuclide behaviour in soil have been analysed. On the basis of natural researches, lab test and mathematical modelling the impact of physical-chemical factors and the soil component composition changes upon the radionuclides migration and sorption in natural dispersed systems (peat, sand, bentonite, kaolin, sapropel) has been investigated. The investigations done allowed to substantiate the mathematical models of the radionuclides migration in the regions of positive and negative temperatures, to develop methods of experimental identification of main transfer characteristics and to compile a data base for these models. (orig.)

  1. Munc13 controls the location and efficiency of dense-core vesicle release in neurons.

    Science.gov (United States)

    van de Bospoort, Rhea; Farina, Margherita; Schmitz, Sabine K; de Jong, Arthur; de Wit, Heidi; Verhage, Matthijs; Toonen, Ruud F

    2012-12-10

    Neuronal dense-core vesicles (DCVs) contain diverse cargo crucial for brain development and function, but the mechanisms that control their release are largely unknown. We quantified activity-dependent DCV release in hippocampal neurons at single vesicle resolution. DCVs fused preferentially at synaptic terminals. DCVs also fused at extrasynaptic sites but only after prolonged stimulation. In munc13-1/2-null mutant neurons, synaptic DCV release was reduced but not abolished, and synaptic preference was lost. The remaining fusion required prolonged stimulation, similar to extrasynaptic fusion in wild-type neurons. Conversely, Munc13-1 overexpression (M13OE) promoted extrasynaptic DCV release, also without prolonged stimulation. Thus, Munc13-1/2 facilitate DCV fusion but, unlike for synaptic vesicles, are not essential for DCV release, and M13OE is sufficient to produce efficient DCV release extrasynaptically.

  2. Assessment of impact of a severe accident at nuclear power plant of Angra dos Reis with release of radionuclides to the atmosphere; Avaliacao do impacto de um acidente severo na usina de Angra dos Reis com liberacao de radionuclideos para a atmosfera

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Andre Silva de

    2015-07-01

    This study had as purpose the assess the impact of a severe accident, and also analyze the dispersion of {sup 131}I in the atmosphere, so that, through concentrating and inhaling dose of the plume, were possible to verify if the results are in accordance with the indicated data by the Plan of Emergency of the CNAAA regarding the Impact Zone and Control. This exercise was performed with the aid of an atmospheric model and a dispersion where to atmospheric modeling we used the data coupling WRF / CALMET and of dispersion, CALPUFF. The suggested accident consists of a Station Blackout at Nuclear Power of Angra (Unit 1), where through the total core involvement, will release 100% of the {sup 131}I to the atmosphere. The value of the total activity in the nucleus to this radionuclide is 7.44 x 1017 Bq, that is relative on the sixth day of burning. This activity will be released through the chimney at a rate in Bq/s in the scenario of 12, 24, 48 and 72 hours of release. Applying the model in the proposed scenario, it is verified that the plume has concentrations of the order of 1020 Bq/m³ and dose of about 108 Sv whose value is beyond of the presented by Eletronuclear in your current emergency plan. (author)

  3. Fire fighting in a radionuclide laboratory

    International Nuclear Information System (INIS)

    Wenzel, H.

    1991-01-01

    A fire-brigade was called to a laboratory which held a handling licence for the radionuclides C-14, T, P-32, Se-75, Mo-99, and S-35. The fire-brigade was unaware of a release of radionuclides. Therefore they used respiratory equipment, and all persons present were subsequently examined for contamination. (DG) [de

  4. Radionuclide Retention in Concrete Wasteforms

    Energy Technology Data Exchange (ETDEWEB)

    Wellman, Dawn M.; Jansik, Danielle P.; Golovich, Elizabeth C.; Cordova, Elsa A.

    2012-09-24

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. Data collected throughout the course of this work will be used to quantify the efficacy of concrete wasteforms, similar to those used in the disposal of LLW and MLLW, for the immobilization of key radionuclides (i.e., uranium, technetium, and iodine). Data collected will also be used to quantify the physical and chemical properties of the concrete affecting radionuclide retention.

  5. Immobilization and controlled release of drug using plasma polymerized thin film

    Energy Technology Data Exchange (ETDEWEB)

    Myung, Sung-Woon [Department of Dental Materials, School of Dentistry, MRC Center, Chosun University, 309 Pilmun-daero, Dong-gu, Gwangju (Korea, Republic of); Jung, Sang-Chul [Department of Environmental Engineering, Sunchon National University, Sunchon 540-742 (Korea, Republic of); Kim, Byung-Hoon, E-mail: kim5055@chosun.ac.kr [Department of Dental Materials, School of Dentistry, MRC Center, Chosun University, 309 Pilmun-daero, Dong-gu, Gwangju (Korea, Republic of)

    2015-06-01

    In this study, plasma polymerization of acrylic acid was employed to immobilize drug and control its release. Doxorubicin (DOX) was immobilized covalently on the glass surface deposited with plasma polymerized acrylic acid (PPAAc) thin film containing the carboxylic group. At first, the PPAAc thin film was coated on a glass surface at a pressure of 1.33 Pa and radio frequency (RF) discharge power of 20 W for 10 min. DOX was immobilized on the PPAAc deposition in a two environment of phosphate buffer saline (PBS) and dimethyl sulfoxide (DMSO) solutions. The DOX immobilized surface was characterized by scanning electron microscope, atomic force microscope and attenuated total reflection Fourier transform infrared spectroscopy. The DOX molecules were more immobilized in PBS than DMSO solution. The different immobilization and release profiles of DOX result from the solubility of hydrophobic DOX in aqueous and organic solutions. Second, in order to control the release of the drug, PPAAc thin film was covered over DOX dispersed layer. Different thicknesses and cross-linked PPAAc thin films by adjusting deposition time and RF discharge power were covered on the DOX layer dispersed. PPAAc thin film coated DOX layer reduced the release rate of DOX. The thickness control of plasma deposition allows controlling the release rate of drug. - Highlights: • Doxorubicin was immobilized on the surface of plasma polymerized acrylic acid thin film. • Release profile of doxorubicin was affected by aqueous and organic solutions. • Plasma polymerized acrylic acid thin film can be used to achieve controlled release.

  6. Immobilization and controlled release of drug using plasma polymerized thin film

    International Nuclear Information System (INIS)

    Myung, Sung-Woon; Jung, Sang-Chul; Kim, Byung-Hoon

    2015-01-01

    In this study, plasma polymerization of acrylic acid was employed to immobilize drug and control its release. Doxorubicin (DOX) was immobilized covalently on the glass surface deposited with plasma polymerized acrylic acid (PPAAc) thin film containing the carboxylic group. At first, the PPAAc thin film was coated on a glass surface at a pressure of 1.33 Pa and radio frequency (RF) discharge power of 20 W for 10 min. DOX was immobilized on the PPAAc deposition in a two environment of phosphate buffer saline (PBS) and dimethyl sulfoxide (DMSO) solutions. The DOX immobilized surface was characterized by scanning electron microscope, atomic force microscope and attenuated total reflection Fourier transform infrared spectroscopy. The DOX molecules were more immobilized in PBS than DMSO solution. The different immobilization and release profiles of DOX result from the solubility of hydrophobic DOX in aqueous and organic solutions. Second, in order to control the release of the drug, PPAAc thin film was covered over DOX dispersed layer. Different thicknesses and cross-linked PPAAc thin films by adjusting deposition time and RF discharge power were covered on the DOX layer dispersed. PPAAc thin film coated DOX layer reduced the release rate of DOX. The thickness control of plasma deposition allows controlling the release rate of drug. - Highlights: • Doxorubicin was immobilized on the surface of plasma polymerized acrylic acid thin film. • Release profile of doxorubicin was affected by aqueous and organic solutions. • Plasma polymerized acrylic acid thin film can be used to achieve controlled release

  7. EMERGENCY RESPONSE PROCEDURES FOR CONTROL OF HAZARDOUS SUBSTANCE RELEASES

    Science.gov (United States)

    Information is provided for selecting the best spill stabilization controls for hazardous substances regulated by the Comprehensive Enviromental Response, Compensation and Liability Act of 1980 (CERCLA). Information is also provided on the onsite assessment of spill severity, app...

  8. Calcium modified edible Canna (Canna edulis L) starch for controlled released matrix

    Science.gov (United States)

    Putri, A. P.; Ridwan, M.; Darmawan, T. A.; Darusman, F.; Gadri, A.

    2017-07-01

    Canna edulis L starch was modified with calcium chloride in order to form controlled released matrix. Present study aim to analyze modified starch characteristic. Four different formulation of ondansetron granules was used to provide dissolution profile of controlled released, two formula consisted of 15% and 30% modified starch, one formula utilized matrix reference standards and the last granules was negative control. Methocel-hydroxypropyl methyl cellulose was used as controlled released matrix reference standards in the third formula. Calcium starch was synthesized in the presence of sodium hydroxide to form gelatinized mass and calcium chloride as the cross linking agent. Physicochemical and dissolution properties of modified starch for controlled released application were investigated. Modified starch has higher swelling index, water solubility and compressibility index. Three of four different formulation of granules provide dissolution profile of controlled released. The profiles indicate granules which employed calcium Canna edulis L starch as matrix are able to resemble controlled drug released profile of matrix reference, however their bigger detain ability lead to lower bioavailability.

  9. Order release strategies to control outsourced operations in a supply chain

    NARCIS (Netherlands)

    Boulaksil, Y.; Fransoo, J.C.

    2007-01-01

    In this paper, we propose and compare three different order release strategies to plan and control outsourced operations in a supply chian where the contract manfacturer is producing different variants of a certain product.

  10. EBS Radionuclide Transport Abstraction

    International Nuclear Information System (INIS)

    Schreiner, R.

    2001-01-01

    The purpose of this work is to develop the Engineered Barrier System (EBS) radionuclide transport abstraction model, as directed by a written development plan (CRWMS M and O 1999a). This abstraction is the conceptual model that will be used to determine the rate of release of radionuclides from the EBS to the unsaturated zone (UZ) in the total system performance assessment-license application (TSPA-LA). In particular, this model will be used to quantify the time-dependent radionuclide releases from a failed waste package (WP) and their subsequent transport through the EBS to the emplacement drift wall/UZ interface. The development of this conceptual model will allow Performance Assessment Operations (PAO) and its Engineered Barrier Performance Department to provide a more detailed and complete EBS flow and transport abstraction. The results from this conceptual model will allow PA0 to address portions of the key technical issues (KTIs) presented in three NRC Issue Resolution Status Reports (IRSRs): (1) the Evolution of the Near-Field Environment (ENFE), Revision 2 (NRC 1999a), (2) the Container Life and Source Term (CLST), Revision 2 (NRC 1999b), and (3) the Thermal Effects on Flow (TEF), Revision 1 (NRC 1998). The conceptual model for flow and transport in the EBS will be referred to as the ''EBS RT Abstraction'' in this analysis/modeling report (AMR). The scope of this abstraction and report is limited to flow and transport processes. More specifically, this AMR does not discuss elements of the TSPA-SR and TSPA-LA that relate to the EBS but are discussed in other AMRs. These elements include corrosion processes, radionuclide solubility limits, waste form dissolution rates and concentrations of colloidal particles that are generally represented as boundary conditions or input parameters for the EBS RT Abstraction. In effect, this AMR provides the algorithms for transporting radionuclides using the flow geometry and radionuclide concentrations determined by other

  11. Organosilane functionalization of halloysite nanotubes for enhanced loading and controlled release

    International Nuclear Information System (INIS)

    Yuan Peng; Southon, Peter D; Kepert, Cameron J; Liu Zongwen

    2012-01-01

    The surfaces of naturally occurring halloysite nanotubes were functionalized with γ-aminopropyltriethoxysilane (APTES), which was found to have a substantial effect on the loading and subsequent release of a model dye molecule. APTES was mostly anchored at the internal lumen surface of halloysite through covalent grafting, forming a functionalized surface covered by aminopropyl groups. The dye loading of the functionalized halloysite was 32% greater than that of the unmodified sample, and the release from the functionalized halloysite was dramatically prolonged as compared to that from the unmodified one. Dye release was prolonged at low pH and the release at pH 3.5 was approximately three times slower than that at pH 10.0. These results demonstrate that organosilane functionalization makes pH an external trigger for controlling the loading of guest on halloysite and the subsequent controlled release. (paper)

  12. Organosilane functionalization of halloysite nanotubes for enhanced loading and controlled release.

    Science.gov (United States)

    Yuan, Peng; Southon, Peter D; Liu, Zongwen; Kepert, Cameron J

    2012-09-21

    The surfaces of naturally occurring halloysite nanotubes were functionalized with γ-aminopropyltriethoxysilane (APTES), which was found to have a substantial effect on the loading and subsequent release of a model dye molecule. APTES was mostly anchored at the internal lumen surface of halloysite through covalent grafting, forming a functionalized surface covered by aminopropyl groups. The dye loading of the functionalized halloysite was 32% greater than that of the unmodified sample, and the release from the functionalized halloysite was dramatically prolonged as compared to that from the unmodified one. Dye release was prolonged at low pH and the release at pH 3.5 was approximately three times slower than that at pH 10.0. These results demonstrate that organosilane functionalization makes pH an external trigger for controlling the loading of guest on halloysite and the subsequent controlled release.

  13. Nanocapsule@xerogel microparticles containing sodium diclofenac: a new strategy to control the release of drugs.

    Science.gov (United States)

    da Fonseca, Letícia Sias; Silveira, Rodrigo Paulo; Deboni, Alberto Marçal; Benvenutti, Edilson Valmir; Costa, Tânia M H; Guterres, Sílvia S; Pohlmann, Adriana R

    2008-06-24

    The aim of this work was to evaluate the potentiality to control the drug release of a new architecture of microparticles organized at the nanoscopic scale by assembling polymeric nanocapsules at the surface of drug-loaded xerogels. Xerogel was prepared by sol-gel method using sodium diclofenac, as hydrophilic drug model, and coated by spray-drying. After coating, the surface areas decreased from 82 to 28 m(2)/g, the encapsulation efficiency was 71% and SEM analysis showed irregular microparticles coated by the nanocapsules. Formulation showed satisfactory gastro-resistance presenting drug release lower than 3% (60 min) in acid medium. In water, the pure drug dissolved 92% after 5 min, uncoated drug-loaded xerogel released 60% and nanocapsule coated drug-loaded xerogel 36%. After 60 min, uncoated drug-loaded xerogel released 82% and nanocapsule coated drug-loaded xerogel 62%. In conclusion, the new system was able to control the release of the hydrophilic drug model.

  14. Metal-organic framework tethering PNIPAM for ON-OFF controlled release in solution.

    Science.gov (United States)

    Nagata, Shunjiro; Kokado, Kenta; Sada, Kazuki

    2015-05-21

    A smart metal-organic framework (MOF) exhibiting controlled release was achieved by modification with a thermoresponsive polymer (PNIPAM) via a surface-selective post-synthetic modification technique. Simple temperature variation readily switches "open" (lower temperature) and "closed" (higher temperature) states of the polymer-modified MOF through conformational change of PNIPAM grafted onto the MOF, resulting in controlled release of the included guest molecules such as resorufin, caffeine, and procainamide.

  15. Laser-activated nano-biomaterials for tissue repair and controlled drug release

    International Nuclear Information System (INIS)

    Matteini, P; Ratto, F; Rossi, F; Pini, R

    2014-01-01

    We present recent achievements of minimally invasive welding of biological tissue and controlled drug release based on laser-activated nano-biomaterials. In particular, we consider new advancements in the biomedical application of near-IR absorbing gold nano-chromophores as an original solution for the photothermal repair of surgical incisions and as nanotriggers of controlled drug release from hybrid biopolymer scaffolds. (laser biophotonics)

  16. Releasable Kinetic Energy-Based Inertial Control of a DFIG Wind Power Plant

    DEFF Research Database (Denmark)

    Lee, Jinsik; Muljadi, Eduard; Sørensen, Poul Ejnar

    2016-01-01

    Wind turbine generators (WTGs) in a wind power plant (WPP) contain different levels of releasable kinetic energy (KE) because of the wake effects. This paper proposes a releasable KE-based inertial control scheme for a doubly fed induction generator (DFIG) WPP that differentiates the contributions....... The proposed scheme adjusts the two loop gains in a DFIG controller depending on its rotor speed so that a DFIG operating at a higher rotor speed releases more KE. The performance of the proposed scheme was investigated under various wind conditions. The results clearly indicate that the proposed scheme...

  17. Controlled-release approaches towards the chemotherapy of tuberculosis

    Directory of Open Access Journals (Sweden)

    Saifullah B

    2012-10-01

    Full Text Available Bullo Saifullah,1 Mohd Zobir B Hussein,1,2 Samer Hasan Hussein Al Ali11Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 2Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology, Universiti Putra Malaysia, Serdang, Selangor, MalaysiaAbstract: Tuberculosis (TB, caused by the bacteria Mycobacterium tuberculosis, is notorious for its lethality to humans. Despite technological advances, the tubercle bacillus continues to threaten humans. According to the World Health Organization's 2011 global report on TB, 8.8 million cases of TB were reported in 2010, with a loss of 1.7 million human lives. As drug-susceptible TB requires long-term treatment of between 6 and 9 months, patient noncompliance remains the most important reason for treatment failure. For multidrug-resistant TB, patients must take second-line anti-TB drugs for 18–24 months and many adverse effects are associated with these drugs. Drug-delivery systems (DDSs seem to be the most promising option for advancement in the treatment of TB. DDSs reduce the adverse effects of drugs and their dosing frequency as well as shorten the treatment period, and hence improve patient compliance. Further advantages of these systems are that they target the disease area, release the drugs in a sustained manner, and are biocompatible. In addition, targeted delivery systems may be useful in dealing with extensively drug-resistant TB because many side effects are associated with the drugs used to cure the disease. In this paper, we discuss the DDSs developed for the targeted and slow delivery of anti-TB drugs and their possible advantages and disadvantages.Keywords: Mycobacterium tuberculosis, drug-delivery system, targeted delivery, anti-TB drug, TB, patient compliance

  18. Colloid-facilitated radionuclide transport: a regulatory perspective

    Science.gov (United States)

    Dam, W. L.; Pickett, D. A.; Codell, R. B.; Nicholson, T. J.

    2001-12-01

    What hydrogeologic-geochemical-microbial conditions and processes affect migration of radionuclides sorbed onto microparticles or native colloid-sized radionuclide particles? The U.S. Nuclear Regulatory Commission (NRC) is responsible for protecting public health, safety, and the environment at numerous nuclear facilities including a potential high-level nuclear waste disposal site. To fulfill these obligations, NRC needs to understand the mechanisms controlling radionuclide release and transport and their importance to performance. The current focus of NRC staff reviews and technical interactions dealing with colloid-facilitated transport relates to the potential nuclear-waste repository at Yucca Mountain, Nevada. NRC staff performed bounding calculations to quantify radionuclide releases available for ground-water transport to potential receptors from a Yucca Mountain repository. Preliminary analyses suggest insignificant doses of plutonium and americium colloids could be derived from spent nuclear fuel. Using surface complexation models, NRC staff found that colloids can potentially lower actinide retardation factors by up to several orders of magnitude. Performance assessment calculations, in which colloidal transport of plutonium and americium was simulated by assuming no sorption or matrix diffusion, indicated no effect of colloids on human dose within the 10,000 year compliance period due largely to long waste-package lifetimes. NRC staff have identified information gaps and developed technical agreements with the U.S. Department of Energy (DOE) to ensure sufficient information will be presented in any potential future Yucca Mountain license application. DOE has agreed to identify which radionuclides could be transported via colloids, incorporate uncertainties in colloid formation, release and transport parameters, and conceptual models, and address the applicability of field data using synthetic microspheres as colloid analogs. NRC is currently

  19. PH-triggered micellar membrane for controlled release microchips

    KAUST Repository

    Yang, Xiaoqiang; Moosa, Basem; Deng, Lin; Zhao, Lan; Khashab, Niveen M.

    2011-01-01

    A pH-responsive membrane based on polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) block copolymer was developed on a model glass microchip as a promising controlled polymer delivery system. The PS-b-P4VP copolymer assembles into spherical and

  20. Polyvinyl alcohol composite nanofibres containing conjugated levofloxacin-chitosan for controlled drug release

    International Nuclear Information System (INIS)

    Jalvandi, Javid; White, Max; Gao, Yuan; Truong, Yen Bach; Padhye, Rajiv; Kyratzis, Ilias Louis

    2017-01-01

    A range of biodegradable drug-nanofibres composite mats have been reported as drug delivery systems. However, their main disadvantage is the rapid release of the drug immediately after application. This paper reports an improved system based on the incorporation of drug conjugated-chitosan into polyvinyl alcohol (PVA) nanofibers. The results showed that controlled release of levofloxacin (LVF) could be achieved by covalently binding LVF to low molecular weight chitosan (CS) via a cleavable amide bond and then blending the conjugated CS with polyvinyl alcohol (PVA) nanofibres prior to electrospinning. PVA/LVF and PVA-CS/LVF nanofibres were fabricated as controls. The conjugated CS-LVF was characterized by FTIR, DSC, TGA and 1 H NMR. Scanning electron microscopy (SEM) showed that the blended CS-PVA nanofibres had a reduced fibre diameter compared to the controls. Drug release profiles showed that burst release was decreased from 90% in the control PVA/LVF electrospun mats to 27% in the PVA/conjugated CS-LVF mats after 8 h in phosphate buffer at 37 °C. This slower release is due to the cleavable bond between LVF and CS that slowly hydrolysed over time at neutral pH. The results indicate that conjugation of the drug to the polymer backbone is an effective way of minimizing burst release behaviour and achieving sustained release of the drug, LVF. - Highlights: • A novel drug delivery system for controlled release of drug was designed. • Composite PVA/conjugated CS-LVF nanofibres was fabricated by electrospinning. • Conjugated chitosan and composite nanofibres were characterized by various techniques. • Release profiles of drug were significantly improved in composite nanofibres containing drug conjugated chitosan.

  1. Polyvinyl alcohol composite nanofibres containing conjugated levofloxacin-chitosan for controlled drug release

    Energy Technology Data Exchange (ETDEWEB)

    Jalvandi, Javid, E-mail: Javid.jlv@gmail.com [CSIRO, Manufacturing Flagship, Bayview Ave, Clayton, Victoria 3168 (Australia); School of Fashion and Textiles, College of Design and Social Context, RMIT University, 25 Dawson Street, Brunswick, Victoria 3056 (Australia); White, Max, E-mail: tamrak@bigpond.com [School of Fashion and Textiles, College of Design and Social Context, RMIT University, 25 Dawson Street, Brunswick, Victoria 3056 (Australia); Gao, Yuan, E-mail: Yuan.Gao@csiro.au [CSIRO, Manufacturing Flagship, Bayview Ave, Clayton, Victoria 3168 (Australia); Truong, Yen Bach, E-mail: Yen.truong@csiro.au [CSIRO, Manufacturing Flagship, Bayview Ave, Clayton, Victoria 3168 (Australia); Padhye, Rajiv, E-mail: rajiv.padhye@rmit.edu.au [School of Fashion and Textiles, College of Design and Social Context, RMIT University, 25 Dawson Street, Brunswick, Victoria 3056 (Australia); Kyratzis, Ilias Louis, E-mail: Louis.kyratzis@csiro.au [CSIRO, Manufacturing Flagship, Bayview Ave, Clayton, Victoria 3168 (Australia)

    2017-04-01

    A range of biodegradable drug-nanofibres composite mats have been reported as drug delivery systems. However, their main disadvantage is the rapid release of the drug immediately after application. This paper reports an improved system based on the incorporation of drug conjugated-chitosan into polyvinyl alcohol (PVA) nanofibers. The results showed that controlled release of levofloxacin (LVF) could be achieved by covalently binding LVF to low molecular weight chitosan (CS) via a cleavable amide bond and then blending the conjugated CS with polyvinyl alcohol (PVA) nanofibres prior to electrospinning. PVA/LVF and PVA-CS/LVF nanofibres were fabricated as controls. The conjugated CS-LVF was characterized by FTIR, DSC, TGA and {sup 1}H NMR. Scanning electron microscopy (SEM) showed that the blended CS-PVA nanofibres had a reduced fibre diameter compared to the controls. Drug release profiles showed that burst release was decreased from 90% in the control PVA/LVF electrospun mats to 27% in the PVA/conjugated CS-LVF mats after 8 h in phosphate buffer at 37 °C. This slower release is due to the cleavable bond between LVF and CS that slowly hydrolysed over time at neutral pH. The results indicate that conjugation of the drug to the polymer backbone is an effective way of minimizing burst release behaviour and achieving sustained release of the drug, LVF. - Highlights: • A novel drug delivery system for controlled release of drug was designed. • Composite PVA/conjugated CS-LVF nanofibres was fabricated by electrospinning. • Conjugated chitosan and composite nanofibres were characterized by various techniques. • Release profiles of drug were significantly improved in composite nanofibres containing drug conjugated chitosan.

  2. Radionuclide examinations

    International Nuclear Information System (INIS)

    Lentle, B.C.

    1989-01-01

    This paper reports on radionuclide examinations of the pancreas. The pancreas, situated retroperitonally high in the epigastrium, was a particularly difficult organ to image noninvasively before ultrasonography and computed tomography (CT) became available. Indeed the organ still remains difficult to examine in some patients, a fact reflected in the variety of methods available to evaluate pancreatic morphology. It is something of a paradox that the pancreas is metabolically active and physiologically important but that its examination by radionuclide methods has virtually ceased to have any role in day-to-day clinical practice. To some extent this is caused by the tendency of the pancreas's commonest gross diseases emdash carcinoma and pancreatitis, for example emdash to result in nonfunction of the entire organ. Disorders of pancreatic endocrine function have generally not required imaging methods for diagnosis, although an understanding of diabetes mellitus and its nosology has been advanced by radioimmunoassay of plasma insulin concentrations

  3. The performance of workload control concepts in job shops : Improving the release method

    NARCIS (Netherlands)

    Land, MJ; Gaalman, GJC

    1998-01-01

    A specific class of production control concepts for jobs shops is based on the principles of workload control. Practitioners emphasise the importance of workload control. However, order release methods that reduce the workload on the shop floor show poor due date performance in job shop simulations.

  4. A review of mathematical modeling and simulation of controlled-release fertilizers.

    Science.gov (United States)

    Irfan, Sayed Ameenuddin; Razali, Radzuan; KuShaari, KuZilati; Mansor, Nurlidia; Azeem, Babar; Ford Versypt, Ashlee N

    2018-02-10

    Nutrients released into soils from uncoated fertilizer granules are lost continuously due to volatilization, leaching, denitrification, and surface run-off. These issues have caused economic loss due to low nutrient absorption efficiency and environmental pollution due to hazardous emissions and water eutrophication. Controlled-release fertilizers (CRFs) can change the release kinetics of the fertilizer nutrients through an abatement strategy to offset these issues by providing the fertilizer content in synchrony with the metabolic needs of the plants. Parametric analysis of release characteristics of CRFs is of paramount importance for the design and development of new CRFs. However, the experimental approaches are not only time consuming, but they are also cumbersome and expensive. Scientists have introduced mathematical modeling techniques to predict the release of nutrients from the CRFs to elucidate fundamental understanding of the dynamics of the release processes and to design new CRFs in a shorter time and with relatively lower cost. This paper reviews and critically analyzes the latest developments in the mathematical modeling and simulation techniques that have been reported for the characteristics and mechanisms of nutrient release from CRFs. The scope of this review includes the modeling and simulations techniques used for coated, controlled-release fertilizers. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Radionuclide transfer

    International Nuclear Information System (INIS)

    Gerber, G.B.

    1993-01-01

    The research project described here had the aim to obtain further information on the transfer of nuclides during pregnancy and lactation. The tests were carried out in mini-pigs and rats receiving unchanging doses of radionuclides with the food. The following findings were revealed for the elements examined: Fe, Se, Cs and Zn were characterized by very high transfer levels in the mother, infant and foetus. A substantial uptake by the mother alone was observed for Co, Ag and Mn. The uptake by the foetus and infant here was 1 to 10 times lower. A preferential concentration in certain tissues was seen for Sr and Tc; the thyroid levels of Tc were about equally high in mothers and infants, while Sr showed less accumulation in the maternal bone. The lanthanide group of substances (Ce, Eu and Gd as well as Y and Ru) were only taken up to a very limited extent. The uptake of the examined radionuclides (Fe, Co, Ag, Ce) with the food ingested was found here to be ten times greater in rats as compared to mini-pigs. This showed that great caution must be observed, if the behaviour of radionuclides in man is extrapolated from relevant data obtained in rodents. (orig./MG) [de

  6. Control of accidental releases of hydrogen selenide in vented storage cabinets

    Science.gov (United States)

    Fthenakis, V. M.; Moskowitz, P. D.; Sproull, R. D.

    1988-07-01

    Highly toxic hydrogen selenide and hydrogen sulfide gases are used in the production of copper-indium-diselenide photovoltaic cells by reactive sputtering. In the event of an accident, these gases may be released to the atmosphere and pose hazards to public and occupational safety and health. This paper outlines an approach for designing systems for the control of these releases given the uncertainty in release conditions and lack of data on the chemical systems involved. Accidental releases of these gases in storage cabinets can be controlled by either a venturi and packed-bed scrubber and carbon adsorption bed, or containment scrubbing equipment followed by carbon adsorption. These systems can effectively reduce toxic gas emissions to levels needed to protect public health. The costs of these controls (˜0.012/Wp) are samll in comparison with current (˜6/Wp) and projected (˜I/Wp) production costs.

  7. Monensin controlled-release intraruminal capsule for control of bloat in pastured dairy cows.

    Science.gov (United States)

    Lowe, L B; Ball, G J; Carruthers, V R; Dobos, R C; Lynch, G A; Moate, P J; Poole, P R; Valentine, S C

    1991-01-01

    Monensin, a polyether ionophore antibiotic, is potentially an important agent for bloat relief in dairy cows grazing temperate legume-based pasture. A series of studies was undertaken to determine the effect of monensin, when delivered continuously in the rumen of lactating dairy cows by means of controlled-release capsules (monensin CRC). Such devices release approximately 300 mg/head/day for 100 d. A short-term pilot study made at Ruakura, New Zealand, tested monensin CRC in cows selected for high susceptibility to bloat and grazing lucerne (Medicago sativa) or red clover (Trifolium pratense). Treatment significantly reduced the incidence of bloat, while milk yield and protein yield were increased. There was no effect on fat yield. Following the pilot study, 6 large-scale field experiments involving a total of 368 lactating dairy cows, were made in Australia and New Zealand to confirm the effectiveness of monensin CRC for bloat control and to measure the effect of such treatment on milk production and composition. A severe bloat problem occurred in 2 experiments, mild bloat occurred in 2 others, while no visual signs of bloat were observed in the remaining 2 experiments. Bloat was significantly (P less than 0.05) reduced by monensin CRC treatment when data was pooled over the 4 experiments in which bloat occurred. Daily milk yield was increased in all experiments from a mean of 17.7 in untreated groups to 18.8 kg/head/day (P less than 0.05) in monensin CRC-treated cows. Protein percentage was not affected by treatment, while there was a decrease from 4.29 to 4.10% fat, although total fat yield was not affected.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Drift-Scale Radionuclide Transport

    International Nuclear Information System (INIS)

    Houseworth, J.

    2004-01-01

    drift. The reason for introducing the fracture-matrix partitioning model is to broaden the conceptual model for flow beneath waste emplacement drifts in a way that does not rely on the specific flow behavior predicted by a dual continuum model and to ensure that radionuclide transport is not underestimated. The fracture-matrix partitioning model provides an alternative method of computing the partitioning of radionuclide releases from drifts without seepage into rock fractures and rock matrix. Drifts without seepage are much more likely to have a significant fraction of radionuclide releases into the rock matrix, and therefore warrant additional attention in terms of the partitioning model used for TSPA

  9. Preparation and characterization of controlled-release fertilizers coated with marine polysaccharide derivatives

    Science.gov (United States)

    Wang, Jing; Liu, Song; Qin, Yukun; Chen, Xiaolin; Xing, Rong'e.; Yu, Huahua; Li, Kecheng; Li, Pengcheng

    2017-09-01

    Encapsulation of water-soluble nitrogen fertilizers by membranes can be used to control the release of nutrients to maximize the fertilization effect and reduce environmental pollution. In this research, we formulated a new double-coated controlled-release fertilizer (CRF) by using food-grade microcrystalline wax (MW) and marine polysaccharide derivatives (calcium alginate and chitosan-glutaraldehyde copolymer). The pellets of water-soluble nitrogen fertilizer were coated with the marine polysaccharide derivatives and MW. A convenient and eco-friendly method was used to prepare the CRF. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to characterize the morphology and composition of the products. The nitrogen-release properties were determined in water using UV-Vis spectrophotometry. The controlled-release properties of the fertilizer were improved dramatically after coating with MW and the marine polysaccharide derivatives. The results show that the double-coated CRFs can release nitrogen in a controlled manner, have excellent controlled-release features, and meet the European Standard for CRFs.

  10. Microfluidic synthesis of microfibers for magnetic-responsive controlled drug release and cell culture.

    Directory of Open Access Journals (Sweden)

    Yung-Sheng Lin

    Full Text Available This study demonstrated the fabrication of alginate microfibers using a modular microfluidic system for magnetic-responsive controlled drug release and cell culture. A novel two-dimensional fluid-focusing technique with multi-inlets and junctions was used to spatiotemporally control the continuous laminar flow of alginate solutions. The diameter of the manufactured microfibers, which ranged from 211 µm to 364 µm, could be well controlled by changing the flow rate of the continuous phase. While the model drug, diclofenac, was encapsulated into microfibers, the dr