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Sample records for radioactive hot particles

  1. Effects of radioactive hot particles on pig skin

    Energy Technology Data Exchange (ETDEWEB)

    Kaurin, D.G.; Baum, J.W.; Schaefer, C.W. [and others

    1997-06-01

    The purpose of these studies was to determine the incidence and severity of lesions resulting from very localized deposition of dose to skin from small (< 0.5 mm) discrete radioactive particles as produced in the work environments of nuclear reactors. Hanford mini-pigs were exposed, both on a slightly off the skin, to localized replicate doses from 0.31 to 64 Gy (averaged over 1 cm{sup 2} at 70 {mu}m depth unless noted otherwise) using Sc-46, Yb-175, Tm-170, and fissioned UC{sub 2} isotopes having maximum beta-particle energies from about 0.3 to 3 MeV. Erythema and scabs (indicating ulceration) were scored for up to 71 days post-irradiation. The responses followed normal cumulative probability distributions, and therefore, no true threshold could be defined. Hence, 10 and 50% scab incidence rates were deduced using probit analyses. The lowest dose which produced 10% incidence was about 1 Gy for Yb-175 (0.5 MeV maximum energy) beta particle exposures, and about 3 to 9 Gy for other isotopes. The histopathology of lesions was determined at several doses. Single exposures to doses as large as 1,790 Gy were also given, and results were observed for up to 144 days post-exposure. Severity of detriment was estimated by analyzing the results in terms of lesion diameter, persistence, and infection. Over 1,100 sites were exposed. Only two exposed sites became infected after doses near 5000 Gy; the lesions healed quickly on treatment. 105 refs., 145 figs., 47 tabs.

  2. Effects of radioactive hot particles on pig skin

    International Nuclear Information System (INIS)

    Kaurin, D.G.; Baum, J.W.; Schaefer, C.W.

    1997-06-01

    The purpose of these studies was to determine the incidence and severity of lesions resulting from very localized deposition of dose to skin from small ( 2 at 70 μm depth unless noted otherwise) using Sc-46, Yb-175, Tm-170, and fissioned UC 2 isotopes having maximum beta-particle energies from about 0.3 to 3 MeV. Erythema and scabs (indicating ulceration) were scored for up to 71 days post-irradiation. The responses followed normal cumulative probability distributions, and therefore, no true threshold could be defined. Hence, 10 and 50% scab incidence rates were deduced using probit analyses. The lowest dose which produced 10% incidence was about 1 Gy for Yb-175 (0.5 MeV maximum energy) beta particle exposures, and about 3 to 9 Gy for other isotopes. The histopathology of lesions was determined at several doses. Single exposures to doses as large as 1,790 Gy were also given, and results were observed for up to 144 days post-exposure. Severity of detriment was estimated by analyzing the results in terms of lesion diameter, persistence, and infection. Over 1,100 sites were exposed. Only two exposed sites became infected after doses near 5000 Gy; the lesions healed quickly on treatment. 105 refs., 145 figs., 47 tabs

  3. Detailed SEM-EPMA investigation of high specific radioactivity particles (hot particles)

    International Nuclear Information System (INIS)

    Burin, K.; Tsacheva, Ts.; Mandjoukov, I.; Mandjoukova, B.

    1993-01-01

    Scanning electron microscope (SEM) images and electron probe microanalysis (EPMA) spectra of a group of hot particles collected in Bulgaria after the Chernobyl accident have been obtained. A technique for hot particle localization is described. The object is irradiated for two days with a β source and the resulting autoradiographs show particles location precisely. High resolution x-ray spectrum of each particle has been obtained using EPMA. The distribution of chemical elements is visualized by colour dot maps representing the regions of interest of the spectrum. It is concluded that apart from reactor fuel the investigated hot particles come from either construction materials or materials used for the covering of the damaged reactor. 7 figs., 2 ref

  4. Hot particles

    International Nuclear Information System (INIS)

    Merwin, S.E.; Moeller, M.P.

    1989-01-01

    Nuclear Regulatory Commission (NRC) licensees are required to assess the dose to skin from a hot particle contamination event at a depth of skin of7mg/cm 2 over an area of 1 cm 2 and compare the value to the current dose limit for the skin. Although the resulting number is interesting from a comparative standpoint and can be used to predict local skin reactions, comparison of the number to existing limits based on uniform exposures is inappropriate. Most incidents that can be classified as overexposures based on this interpretation of dose actually have no effect on the health of the worker. As a result, resources are expended to reduce the likelihood that an overexposure event will occur when they could be directed toward eliminating the cause of the problem or enhancing existing programs such as contamination control. Furthermore, from a risk standpoint, this practice is not ALARA because some workers receive whole body doses in order to minimize the occurrence of hot particle skin contaminations. In this paper the authors suggest an alternative approach to controlling hot particle exposures

  5. α-particle radioactivity of hot particles from the Esk estuary

    International Nuclear Information System (INIS)

    Hamilton, E.I.

    1981-01-01

    Transuranium radionuclides (Pu, Am and Cm) present in effluents discharged into the north-east Irish Sea by British Nuclear Fuels Limited, Windscale, Cumbria, UK, are found in sediment and biota of the Esk estuary approximately 10 km to the south. The site of the present investigation was at Newbiggin and the materials examined were suspended particulate debris samples at the sea surface, bottom sediments and some forms of biota collected in September 1977. It is shown here that hot particles (defined as small volumes of material emitting α particles recorded in a dielectric detector as dense clusters of tracks from a common origin) found in the estuary are likely to be original effluent debris derived from the processing of Magnox uranium fuel elements and not formed in situ as a result of natural processes common to the estuary. (author)

  6. Skin dose from distributed radioactive sources and hot particles - Regulations and recommendations

    International Nuclear Information System (INIS)

    Porter, S.W.

    1991-01-01

    The issues concerning Beta Dosimetry, Hot Particle Dosimetry, and associated dose to skin have been highlighted since the 1979 TMI-2 accident report of the Presidential Commission. The conclusions drawn from the DOE/EML International Beta Dosimetry Symposium of 1983 are still valid. The questions of location(s) of the radiosensitive layer of human skin, the most valid method of skin dose measurement and interpretation of associated radiobiological data are still lingering. The need for improving beta calculation standards and procedures are more evident now than in 1983. This paper will discuss the newest ICRP and NCRP recommendations, as well as the regulations and guidelines from the NRC. I would expect that the draft recommendations published in this paper will be considerably changed by the time of the January, 1991 presentation of this paper

  7. Characteristics of 'hot particles' from the Chernobyl radioactive fallout and some comments on the relevant radiological risk

    International Nuclear Information System (INIS)

    Jaracz, P.; Mirowski, S.; Piasecki, E.; Wilhelmi, Z.

    2004-01-01

    Paper reviews some radiative characteristics of 'hot particles' (HP) - a particulate fraction of the Chernobyl fallout. The work is based mostly on results of HP investigations of the Warsaw group. A classification of hot particles in their γ activity contents as well as some suggestions about possible mechanisms of their formation are provided. A comparison between activities of the Chernobyl hot particles and the ones from nuclear weapon tests of the early 60-ties is made. Some comments on health detriment caused by HPs are included. (author)

  8. 'Hot particle' intercomparison dosimetry

    International Nuclear Information System (INIS)

    Kaurin, D.G.L.; Baum, J.W.; Charles, M.W.; Darley, D.P.J.; Durham, J.S.; Scannell, M.J.; Soares, C.G.

    1996-01-01

    Dosimetry measurements of four 'hot particles' were made at different density thickness values using five different methods. The hot particles had maximum dimensions of 650 μm and maximum beta energies of 0.97, 046, 0.36, and 0.32 MeV. Absorbers were used to obtain the dose at different depths for each dosimeter. Measurements were made using exoelectron dosimeters, an extrapolation chamber, NE Extremity Tape Dosimeters (tm), Eberline RO-2 and RO-2A survey meters, and two sets of GafChromic (tm) dye film with each set read out at a different institution. From these results the dose was calculated averaged over 1 cm 2 of tissue at 18, 70, 125, and 400 μm depth. Comparisons of tissue-dose averaged over 1 cm 2 for 18, 70, and 125 μm depth based on interpolated measured values, were within 30% for the GafChromic (tm) dye film, extrapolation chamber, NE Extremity Tape Dosimeters (tm), and Eberline RO-2 and 2A (tm) survey meters except for the hot particle with 0.46 MeV maximum beta energy. The results for this source showed differences of up to 60%. The extrapolation chamber and NE Extremity Tape dosimeters under-responded for measurements at 400 μm by about a factor of 2 compared with the GafChromic dye films for two hot particles with maximum beta energy of 0.32 and 0.36 MeV which each emitted two 100% 1 MeV photons per disintegration. Tissue doses determined using exoelectron dosimeters were a factor of 2 to 5 less than those determined using other dosimeters, possibly due to failures of the equipment. (author)

  9. Theory of hot particle stability

    International Nuclear Information System (INIS)

    Berk, H.L.; Wong, H.V.; Tsang, K.T.

    1986-10-01

    The investigation of stabilization of hot particle drift reversed systems to low frequency modes has been extended to arbitrary hot beta, β/sub H/ for systems that have unfavorable field line curvature. We consider steep profile equilibria where the thickness of the pressure drop, Δ, is less than plasma radius, r/sub p/. The analysis describes layer modes which have mΔ/r/sub p/ 2/3. When robust stability conditions are fulfilled, the hot particles will have their axial bounce frequency less than their grad-B drift frequency. This allows for a low bounce frequency expansion to describe the axial dependence of the magnetic compressional response

  10. Nuclear track radiography of 'hot' aerosol particles

    International Nuclear Information System (INIS)

    Boulyga, S.F.; Kievitskaja, A.I.; Kievets, M.K.; Lomonosova, E.M.; Zhuk, I.V.; Yaroshevich, O.I.; Perelygin, V.P.; Petrova, R.; Brandt, R.; Vater, P.

    1999-01-01

    Nuclear track radiography was applied to identify aerosol 'hot' particles which contain elements of nuclear fuel and fallout after Chernobyl NPP accident. For the determination of the content of transuranium elements in radioactive aerosols the measurement of the α-activity of 'hot' particles by SSNTD was used in this work, as well as radiography of fission fragments formed as a result of the reactions (n,f) and (γ,f) in the irradiation of aerosol filters by thermal neutrons and high energy gamma quanta. The technique allowed the sizes and alpha-activity of 'hot' particles to be determined without extracting them from the filter, as well as the determination of the uranium content and its enrichment by 235 U, 239 Pu and 241 Pu isotopes. Sensitivity of determination of alpha activity by fission method is 5x10 -6 Bq per particle. The software for the system of image analysis was created. It ensured the identification of track clusters on an optical image of the SSNTD surface obtained through a video camera and the determination of size and activity of 'hot' particles

  11. Recommendations, requirements, and radioactive particles

    International Nuclear Information System (INIS)

    Bell, J.M.

    1991-01-01

    Hot particles consisting of activated metal debris and fuel fragments have received increased attention in the last five years. This increased attention resulted from the increased use of more sensitive whole body friskers at nuclear power plants, the relatively high local skin doses associated with the particles, and skin dose limits that were established before hot particles, and skin dose limits that were established before hot particles became a problem and before radiobiological effects data for the particles became available. The skin dose distribution and biological effects associated with hot particles differ from those associated with more uniform skin contamination and differences exist in the scientific community as to which effects should be protected against by a limit on exposures from particles. The NRC staff recognized the need for provisions in the Federal regulations specific to hot particle exposures and requested guidance from the National Council on Radiation Protection and Measurements (NCRP). NCRP Report No. 106 was provided to the NRC early in 1990. The International Commission on Radiological Protection (ICRP) is also developing recommendations for limits on exposures from hot particles. The NRC is supporting research on hot particle effects and will likely develop a rule for hot particle exposures

  12. Hot particles in industrial waste and mining tailings

    CERN Document Server

    Selchau-Hansen, K; Freyer, K; Treutler, C; Enge, W

    1999-01-01

    Industrial waste was studied concerning its radioactive pollution. Using known properties of the solid state nuclear track detector CR-39 we found among a high concentration of more or less homogeneously distributed single alpha-tracks discrete spots of very high enrichments of alpha-particles created by so called hot particles. We will report about the alpha-activity, the concentration of hot particles and about their ability to be air borne.

  13. Rain scavenging of radioactive particles

    International Nuclear Information System (INIS)

    Williams, A.L.

    1975-01-01

    An assessment is made of the rainout of airborne radioactive particles from a nuclear detonation with emphasis on the microphysical removal processes. For submicron particles the scavenging processes examined are Brownian and turbulent diffusion to cloud droplets. For particles larger than 1 μm radius, nucleation scavenging is examined. For various particle size and radioactivity distributions, it is found that from 27 to 99 percent of the radioactivity is attached to cloud droplets and subject to rapid removal by rain. (U.S.)

  14. Nuclear track radiography of 'hot' aerosol particles

    CERN Document Server

    Boulyga, S F; Kievets, M K; Lomonosova, E M; Zhuk, I V; Yaroshevich, O I; Perelygin, V P; Petrova, R I; Brandt, R; Vater, P

    1999-01-01

    Nuclear track radiography was applied to identify aerosol 'hot' particles which contain elements of nuclear fuel and fallout after Chernobyl NPP accident. For the determination of the content of transuranium elements in radioactive aerosols the measurement of the alpha-activity of 'hot' particles by SSNTD was used in this work, as well as radiography of fission fragments formed as a result of the reactions (n,f) and (gamma,f) in the irradiation of aerosol filters by thermal neutrons and high energy gamma quanta. The technique allowed the sizes and alpha-activity of 'hot' particles to be determined without extracting them from the filter, as well as the determination of the uranium content and its enrichment by sup 2 sup 3 sup 5 U, sup 2 sup 3 sup 9 Pu and sup 2 sup 4 sup 1 Pu isotopes. Sensitivity of determination of alpha activity by fission method is 5x10 sup - sup 6 Bq per particle. The software for the system of image analysis was created. It ensured the identification of track clusters on an optical imag...

  15. Gamma-spectrometric examination of hot particles emitted during the Chernobyl accident

    International Nuclear Information System (INIS)

    Balashazy, I.; Szabadine-Szende, G.; Loerinc, M.; Zombori, P.

    1987-05-01

    Ge(Li) gamma-spectrometric examination of hot particles prepared from air filtered dust of Budapest air after the Chernobyl accident is presented. The method of separating hot particles is described and their concentration in the air is determined. The radioactive isotope composition of hot particles is discussed and compared with that of dust samples. Finally, the inhalation probability and radiation burden of hot particles are evaluated. (author)

  16. 'Hot' particles in the atmosphere (Vilnius, 1986)

    International Nuclear Information System (INIS)

    Lujanas, V.; Shpirkauskaite, N.

    1992-01-01

    After the Chernobyl accident in the atmosphere above Vilnius the alpha-and beta- 'hot' particles were discovered. The amount of particles and their size were measured by the alpha-radiography. After the exposition of nuclear plates the 'auroras' of the beta hot particles were of the size 0.37-22.2 μm. The change in time of the beta- 'hot' particles amount in the ground level air from the 25th of April to the 9th of May, 1986 was given. The amount of this particles deposited in the adult man respiratory tract was calculated. The energy of the discovered 8 'hot' alpha-particles ranged from 4.2 to 6.6 MeV. All the samples in which alpha- 'hot' particles found were taken in anticyclone conditions. (author). 1 tab., 1 ref

  17. Fastener tightening in a radioactive (hot) cell

    International Nuclear Information System (INIS)

    Kalk, J.J.

    1986-01-01

    Accurate remote tightening of fasteners in a radioactive (Hot) cell can be a very exasperating experience. Viewing can be difficult (in many places) and work sometimes must be done using mirrors and/or cameras. If electro mechanical manipulators are used, the operator has no ''feel,'' which often can result in cross threading, or improper torquing of fasteners. At the Interim Examination and Maintenance (IEM) Cell, where reactor components from the Fast Flux Test Facility (FFTF) are disassembled, these problems are prevalent because three of the IEM Cell walls have no windows. Electric impact wrenches were first proposed and tested for the IEM Cell, but the combined effects of radiation, dry argon atmosphere and poor visibility radically altered the cell tool development philosophy. This change in philosophy is reflected in the development of several simple fastener tightening devices

  18. Fastener tightening in a radioactive (hot) cell

    International Nuclear Information System (INIS)

    Kalk, J.J.

    1987-01-01

    Accurate remote tightening of fasteners in a radioactive (hot) cell can be a very exasperating experience. Viewing can be difficult (in many places) and work sometimes must be done using mirrors and/or cameras. If electro mechanical manipulators are used, the operator has no feel, which often can result in cross threading, or improper torquing of fasteners. At the Interim Examination and Maintenance (IEM) Cell, where reactor components from the Fast Flux Testing Facility (FFTF) are disassembled, these problems are prevalent because three of the IEM Cell walls have no windows. Electric impact wrenches were first proposed and tested for the IEM Cell, but the combined effects of radiation, dry argon atmosphere and poor visibility radically altered the cell tool development philosophy. This change in philosophy is reflected in the development of several simple fastener tightening devices

  19. Nuclear track radiography of 'hot' aerosol particles

    Energy Technology Data Exchange (ETDEWEB)

    Boulyga, S.F.; Kievitskaja, A.I.; Kievets, M.K.; Lomonosova, E.M.; Zhuk, I.V.; Yaroshevich, O.I.; Perelygin, V.P.; Petrova, R.; Brandt, R.; Vater, P

    1999-06-01

    Nuclear track radiography was applied to identify aerosol 'hot' particles which contain elements of nuclear fuel and fallout after Chernobyl NPP accident. For the determination of the content of transuranium elements in radioactive aerosols the measurement of the {alpha}-activity of 'hot' particles by SSNTD was used in this work, as well as radiography of fission fragments formed as a result of the reactions (n,f) and ({gamma},f) in the irradiation of aerosol filters by thermal neutrons and high energy gamma quanta. The technique allowed the sizes and alpha-activity of 'hot' particles to be determined without extracting them from the filter, as well as the determination of the uranium content and its enrichment by {sup 235}U, {sup 239}Pu and {sup 241}Pu isotopes. Sensitivity of determination of alpha activity by fission method is 5x10{sup -6} Bq per particle. The software for the system of image analysis was created. It ensured the identification of track clusters on an optical image of the SSNTD surface obtained through a video camera and the determination of size and activity of 'hot' particles00.

  20. Experimental approach to Chernobyl hot particles

    International Nuclear Information System (INIS)

    Tcherkezian, V.; Shkinev, V.; Khitrov, L.; Kolesov, G.

    1994-01-01

    An experimental approach to the investigation of Chernobyl hot particles and some results are presented in this study. Hot particles (HP) were picked out from soil samples collected during the 1986-1990 radiogeochemical expeditions in the contaminated zone (within 30 km of the Nuclear Power Plant). A number of hot particles were studied to estimate their contribution to the total activity, investigate their surface morphology and determine the size distribution. Hot particles contribution to the total activity in the 30 km zone was found to be not less than 65%. Investigation of HP element composition (by neutron activation analysis and EPMA) and radionuclide composition (direct alpha- and gamma-spectrometry, including determination of Pu and Am in Hp) revealed certain peculiarities of HP, collected in the vicinity of the damaged Nuclear Power Plant. Some particles were shown to contain uranium and fission products in proportion to one another, correlating with those in the partially burnt fuel, which proves their 'fuel' origin. Another part of the HP samples has revealed element fractionation as well as the presence of some terrestrial components. (Author)

  1. Multiple sample, radioactive particle counting apparatus

    International Nuclear Information System (INIS)

    Reddy, R.R.V.; Kelso, D.M.

    1978-01-01

    An apparatus is described for determining the respective radioactive particle sample count being emitted from radioactive particle containing samples. It includes means for modulating the information on the radioactive particles being emitted from the samples, coded detecting means for sequentially detecting different respective coded combinations of the radioactive particles emitted from more than one but less than all of the samples, and processing the modulated information to derive the sample count for each sample. It includes a single light emitting crystal next to a number of samples, an encoder belt sequentially movable between the crystal and the samples. The encoder belt has a coded array of apertures to provide corresponding modulated light pulses from the crystal, and a photomultiplier tube to convert the modulated light pulses to decodable electrical signals for deriving the respective sample count

  2. Alpha-emitting 'hot particles' in the vicinity of BNFL Sellafield, Cumbria

    International Nuclear Information System (INIS)

    Whittall, A.J.; Tossell, P.J.

    2000-01-01

    In a survey of environmental samples in the vicinity of BNFL Sellafield, two alpha-emitting radioactive particles were found in samples of grass. One particle appears to be of mineral origin, the other was not definitively identified, but may be a fragment of fuel cladding. Conservative estimates of the activities of these particles are very low. The abundance of radioactive particles in the terrestrial food chain appears to be low, with no evidence for any alpha-emitting hot particles in foodstuffs for consumption by humans. Results suggest that there is no significant dose to man through inhalation or ingestion pathways. (author)

  3. A practical methodology of radiological protection for the reduction of hot particles in BWR type reactors

    International Nuclear Information System (INIS)

    Alvarez G, G.

    1991-01-01

    The purpose of this work, in general form, is to describe a practical method for reduction of hot particles generated as consequence of the operational activities of BWR nuclear reactors. This methodology provides a description of the localizations and/or probable activities of finding particles highly radioactive denominated hot particles. For this purpose it was developed a strategy based on the decontamination lineaments, as well as the manipulation, gathering, registration, contention, documentation, control and final disposition of the hot particles. In addition, some recommendations are reiterated and alternative, in order to gathering the hot particles in a dynamic way given to the activities of the personal occupationally exposed in highly radioactive areas. The structure of the methodology of hot particles is supported in the radiological controls based on the Code of Federal Regulation 10 CFR 20 as well as the applicable regulatory documents. It provides an idea based on administrative controls of radiological protection, in order to suggesting the responsibilities and necessary directing for the control of the hot particles required in nuclear plants of the BWR type. (author)

  4. [The interaction of soil micromycetes with "hot" particles in a model system].

    Science.gov (United States)

    Zhdanova, N N; Lashko, T N; Redchits, T I; Vasilevskaia, A I; Borisiuk, L G; Siniavskaia, O I; Gavriliuk, V I; Muzalev, P N

    1991-01-01

    A model system which permits observing for a long time and fixing interaction of fungi with a radiation source has been created on the basis of an isolated "hot" particle, deficient mineral medium (saccharose content 60 mg/l) and suspension of fungal conidia. Five species (six strains) of micromycetes isolated from radionuclide-contaminated soils and fifteen "hot" particles have been tested. It has been found out for the first time that Cladosporium cladosporioides and Penicillium roseo-purpureum are able actively overgrow "hot" particles whose radioactivity did not exceed 3.1-1.0(-7) Ci by gamma-spectrum and to destroy them 50-150 days later. Certain changes in morphology of fungi-destructors of "hot" particles are revealed. A problem on ecological significance of the found phenomenon is discussed.

  5. Particle beam generator using a radioactive source

    Science.gov (United States)

    Underwood, D.G.

    1993-03-30

    The apparatus of the present invention selects from particles emitted by a radioactive source those particles having momentum within a desired range and focuses the selected particles in a beam having at least one narrow cross-dimension, and at the same time attenuates potentially disruptive gamma rays and low energy particles. Two major components of the present invention are an achromatic bending and focusing system, which includes sector magnets and quadrupole, and a quadrupole doublet final focus system. Permanent magnets utilized in the apparatus are constructed of a ceramic (ferrite) material which is inexpensive and easily machined.

  6. Mobility of radioactive colloidal particles in groundwater

    International Nuclear Information System (INIS)

    Nuttall, H.E.; Long, R.L.

    1993-01-01

    Radiocolloids are a major factor in the rapid migration of radioactive waste in groundwater. For at least two Los Alamos National Laboratory (LANL) sites, researchers have shown that groundwater colloidal particles were responsible for the rapid transport of radioactive waste material in groundwater. On an international scale, a review of reported field observations, laboratory column studies, and carefully collected field samples provides compelling evidence that colloidal particles enhance both radioactive and toxic waste migration. The objective of this project is to understand and predict colloid-contaminant migration through fundamental mathematical models, water sampling, and laboratory experiments and use this information to develop an effective and scientifically based colloid immobilization strategy. The article focuses on solving the suspected radiocolloid transport problems at LANL's Mortandad Canyon site. (author) 6 figs., 5 tabs., 18 refs

  7. Natural radioactivity in hot and mineral waters in Syria

    International Nuclear Information System (INIS)

    Othman, I.; Abbass, M.; Kattan, Z.

    1994-08-01

    A study of water chemistry and radioactivity of hot and mineral ground waters was conducted in Syria in order to determine the natural radioactivity levels as well as the mobility process of major radionuclides in the studied systems. The water samples were collected generally from carbonate and basaltic aquifer systems. The chemistry of groundwaters was a reflection of the rock type, while no relationship was found between the radionuclide activities and water temperatures. The increase of 222 Rn concentration in hot and mineral waters was accompanied by a similar increase of the concentration of its patent radionuclides (U t ot and 226 Ra). In parallel, the relative increase of 222 Rn concentration was correlated significantly with the presence of the large faults systems prevailing in the studied areas (Palmyrides and Great African Faults Systems). In all the cases, the radionuclide activity levels were below the maximum contaminant levels given for drinking water and health effects. (author). 11 refs., 7 figs., 8 tabs

  8. The origin, composition and distribution of 'hot particles' derived from the nuclear industry and dispersed in the environment

    International Nuclear Information System (INIS)

    Hamilton, E.I.; Clifton, R.J.

    1987-10-01

    Today, recent sediments of the Esk estuary, Cumbria, contain few hot particles derived from BNF compared with those deposited during peak releases of 1972-74. Overall the hot particles account for about 10% of the total alpha particle activity of the sediments. At some horizons, in buried sediments, concentrations of hot particles probably represent rapid transport on the sea surface under conditions of minimum erosion. Similar particles, usually less well defined, occur in accreting sediments but are corroded. Representative types of the most radioactive particles have been isolated and contain Pu, Am and Cm but only trace amounts of naturally occuring alpha emitters. Microprobe analysis of these particles often shows the presence of fairly pure uranium as the major element. On the basis of radioactivity and elemental composition many of these particles appear to be irradiated nuclear fuel debris. (author)

  9. An ALARA-conscious hot particle control program

    International Nuclear Information System (INIS)

    Doolittle, W.W.; Bredvad, R.S.; Bevelacqua, J.J.

    1992-01-01

    In 1989 approximately twenty-five percent of the radiation dose received by the Point Beach Nuclear Plant (PBNP) Health Physics group was due to its hot particle control program. The Health Physics group initiated a review of the program with the objective of decreasing the dose expenditure for hot particle control while maintaining a high standard for hot particle detection and control. In this paper the methods and results of this evaluation are described. The components of the hot particle control program, rules of thumb, and radionuclide composition at PBNP are presented

  10. Automated contamination monitoring for hot particles

    International Nuclear Information System (INIS)

    Johnstone, G.; Case, L.

    1987-01-01

    INS Corp., the largest nuclear laundry company in the United States, has recently developed two types of automated contamination monitoring systems: 1) the Automated Laundry Monitor (ALM), which provides quality assurance monitoring for protective clothing contamination and 2) a low-level automated monitoring system for Plastic Volume Reduction Service (PVRS). The presentation details the inaccuracies associated with hand-probe frisking which led to the development of the ALM. The ALM was designed for 100% quality assurance monitoring of garments to the most stringent customer requirements. A review of why the ALM is essential in verifying the absence of hot particles on garments is given. The final topic addresses the expansion of the ALM technology in support of the INS Plastic Volume Reduction Service by monitoring decontaminated plastics to free release levels. This presentation reviews the design and operation of both monitoring systems

  11. Skin Dose Assessment by Hot Particles in Domestic Nuclear Power Plant

    International Nuclear Information System (INIS)

    Choi, Bo Yeol; Cho, Woon Kap; Lee, Jai Ki

    2009-01-01

    Since a contamination event by hot particles happened due to damaged nuclear fuel at a nuclear power plant (NPP) in the 1980's, skin exposure resulted from hot particles has gotten considerable attention from all the radiation workers in the nuclear industry. In particular, contamination incident caused by hot particles which happened at a NPP in Susquehanna proved that there existed hot particles with the radioactivity of 0.7 GBq, 0.78 GBq, and even 2.78 GBq at maximum. One of these particles was found on a worker's shoe and gave out a dose of 170 mSv. Although there has been no contamination event reported in domestic NPPs which are caused by hot particles, it is hard to conclude that there is no possibility of such contamination for radiation workers. The contaminated samples employed in this study were taken from local NPPs and supposes a case of a worker's skin contaminated by hot particles to evaluate the dose provided to the worker's skin

  12. Approximate particle number projection in hot nuclei

    International Nuclear Information System (INIS)

    Kosov, D.S.; Vdovin, A.I.

    1995-01-01

    Heated finite systems like, e.g., hot atomic nuclei have to be described by the canonical partition function. But this is a quite difficult technical problem and, as a rule, the grand canonical partition function is used in the studies. As a result, some shortcomings of the theoretical description appear because of the thermal fluctuations of the number of particles. Moreover, in nuclei with pairing correlations the quantum number fluctuations are introduced by some approximate methods (e.g., by the standard BCS method). The exact particle number projection is very cumbersome and an approximate number projection method for T ≠ 0 basing on the formalism of thermo field dynamics is proposed. The idea of the Lipkin-Nogami method to perform any operator as a series in the number operator powers is used. The system of equations for the coefficients of this expansion is written and the solution of the system in the next approximation after the BCS one is obtained. The method which is of the 'projection after variation' type is applied to a degenerate single j-shell model. 14 refs., 1 tab

  13. Measurements and calculations of doses from radioactive particles

    International Nuclear Information System (INIS)

    Leroux, J.B.; Herbaut, Y.

    1996-01-01

    Three Mile Island (TMI) and Tchernobyl reactor accidents have revealed the importance of the skin exposure to beta radiation produced by small high activity sources, named 'hot particles'. In nuclear power reactors, they may arise as small fragments of irradiated fuel or material which have been neutron activated by passing through the reactor co. In recent years, skin exposure to hot particles has been subject to different limitation criteria, formulated by AIEA, ICRP, NCRP working groups. The present work is the contribution of CEA Grenoble to a contract of the Commission of the European communities in cooperation with several laboratories: University of Birmingham, University of Toulouse and University of Montpellier with the main goal to check experiments and calculations of tissue dose from 60 Co radioactive particles. This report is split up into two parts: hot particle dosimetry close to a 60 Co spherical sample with an approximately 200 μm diameter, using a PTW extrapolation chamber model 233991; dose calculations from two codes: the Varskin Mod 2 computer code and the Hot 25 S2 Monte Carlo algorithm. The two codes lead to similar results; nevertheless there is a large discrepancy (of about 2) between calculations and PTW measurements which are higher by a factor of 1.9. At a 70 μm skin depth and for 1 cm 2 irradiated area, the total (β + γ) tissue dose rate delivered by a spherical ( φ = 200 μm) 60 Co source, in contact with skin, is of the order of 6.1 10 -2 nGy s -1 Bq -1 . (author)

  14. Research and systematization of 'hot' particles in the Semipalatinsk nuclear test site soils - methodology and first results

    International Nuclear Information System (INIS)

    Gorlachev, I.D.; Knyazev, B.B.; Kvochkina, T.N.; Lukashenko, S.N.

    2005-01-01

    Full text: Sources of soil activity in Semipalatinsk Nuclear Test Site (SNTS) could be both 'hot' particles dimensions from tens microns to units millimeters and sub-microns particles determining a matrix activity of soil samples. The fractionating of radionuclides and formation of 'hot' particles radionuclide composition arose from temperature changes and complicated nuclear-physical and thermodynamics processes occurring in a fire ball and cloud of nuclear explosion. Knowledge of 'hot' particles physical-chemical properties is needed for evaluation of radioactive products migration in the environment and danger level of the people external and internal exposure. Moreover, minute information about the structure and compound of 'radioactive' particles can be useful for specification of processes occurring in a fiery sphere when conducting explosions of different phylum and also for specification of radioactive fallout forming mechanism. The main polluted spots of SNTS could be divided into the four the species depending on nuclear explosion phylum. Species of radionuclide and their distribution for the different nuclear explosions are able to differ considerably. Therefore, several most typical areas for the each phylum test were selected and twenty soil samples were collected to reveal their radionuclide pollution peculiarities. Collected soil samples were separated into the five granulometric fractions: 1 mm - 2 mm, 0.5 mm - 1 mm. 0.28 mm-0.5 mm, 0.112 mm - 0.28 mm and 1 mm), 210 'hot' particles of second fraction (1>f>0.5 mm) and 154 'hot' particles of third fraction (0.5>f>0.28 mm) have been selection from the twelve SNTS soil samples by the compelled fission and visual identification methods. Main sources of soil samples and 'hot' particles activities are 239+240 Pu, 241 Am, 137 Cs and 152 Eu isotopes.In addition to the described works the special sampling of large 'hot' particles (dimension more than 2 mm) was carried out in areas of the ground and air tests

  15. Hot beta particles in the lung: Results from dogs exposed to fission product radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, F.F.; Griffith, W.C.; Hobbs, C.H. [and others

    1995-12-01

    The Chernobyl nuclear reactor accident resulted in the release of uranium dioxide fuel and fission product radionuclides into the environment with the fallout of respirable, highly radioactive particles that have been termed {open_quotes}hot beta particles.{close_quotes} There is concern that these hot beta particles (containing an average of 150-20,000 Bq/particle), when inhaled and deposited in the lung, may present an extraordinary hazard for the induction of lung cancer. We reviewed data from a group of studies in dogs exposed to different quantities of beta-emitting radionuclides with varied physical half-lives to determine if those that inhaled hot beta particles were at unusual risk for lung cancer. This analysis indicates that the average dose to the lung is adequate to predict biologic effects of lung cancer for inhaled beta-emitting radionuclides in the range of 5-50 Gy to the lung and with particle activities in the range of 0.10-50 Bq/particle.

  16. Spot Ignition of Natural Fuels by Hot Metal Particles

    OpenAIRE

    Urban, James Linwood

    2017-01-01

    The spot ignition of combustible material by hot metal particles is an important pathway by which wildland and urban spot fires and smolders are started. Upon impact with a fuel, such as dry grass, duff, or saw dust, these particles can initiate spot fires by direct flaming or smoldering which can transition to a flame. These particles can be produced by processes such as welding, powerline interactions, fragments from bullet impacts, abrasive cutting, and pyrotechnics. There is little publi...

  17. Chapter 2. Peculiarities of radioactive particle formation and isotope fractionation resulted from underground nuclear explosions

    International Nuclear Information System (INIS)

    1996-01-01

    Radioactive particles, forming terrain fallouts from underground nuclear explosion differ sufficiently from radioactive particles, produced by atmospheric nuclear explosions. Patterns of underground nuclear explosion development, release of radioactivity to the atmosphere, formation of a cloud and base surge, peculiarities of formed radioactive particles, data on isotope fractionation in radioactive particles are presented. Scheme of particle activation, resulted from underground explosions is given

  18. Do Chernobyl hot particles represent a public health hazard? (Biomedical and dosimetric aspects of hot particles)

    Energy Technology Data Exchange (ETDEWEB)

    Likhtarev, I; Repin, V; Bondarenko, O; Nechaev, S

    1994-12-31

    A model is developed to assess the risk of lung cancer from hot particle (HP) inhalation. It is based on linear dimensions of the lings parts, their histological structure, HP dose distribution radiobiological HP impact factors. The deposition probability of different aerosol size HP is estimated for various parts of human respiratory system. The epithelium on bronchial tree and the secretory cells in bronchial glands are identified as most sensitive to HP. A comparison of radiobiological effects of uniform and discrete radiation sources was carried out on culture of embryonic mouse fibroblasts. For doses up to 10{sup -3} Gy there is a good agreement between experimentally obtained HP-induced F and theoretical curves. As the dose increases the experimental value of F reaches a peak at 1 Gy which is not predicted theoretically. The coefficients of blast transformation induced by HP and by uniform radiation become equal at 3 Gy. Above 3 Gy the uniform radiation becomes 10 -10{sup 3} times more dangerous. It is concluded that local point-source irradiation by a HP is associated with 10 - 10{sup 3} times less risk of radiation-induced tumour than irradiation with the same activity idistributed diffusely. 27 figs., 13 tabs., 59 refs.

  19. Do Chernobyl hot particles represent a public health hazard? (Biomedical and dosimetric aspects of hot particles)

    International Nuclear Information System (INIS)

    Likhtarev, I.; Repin, V.; Bondarenko, O.; Nechaev, S.

    1993-01-01

    A model is developed to assess the risk of lung cancer from hot particle (HP) inhalation. It is based on linear dimensions of the lings parts, their histological structure, HP dose distribution radiobiological HP impact factors. The deposition probability of different aerosol size HP is estimated for various parts of human respiratory system. The epithelium on bronchial tree and the secretory cells in bronchial glands are identified as most sensitive to HP. A comparison of radiobiological effects of uniform and discrete radiation sources was carried out on culture of embryonic mouse fibroblasts. For doses up to 10 -3 Gy there is a good agreement between experimentally obtained HP-induced F and theoretical curves. As the dose increases the experimental value of F reaches a peak at 1 Gy which is not predicted theoretically. The coefficients of blast transformation induced by HP and by uniform radiation become equal at 3 Gy. Above 3 Gy the uniform radiation becomes 10 -10 3 times more dangerous. It is concluded that local point-source irradiation by a HP is associated with 10 - 10 3 times less risk of radiation-induced tumour than irradiation with the same activity idistributed diffusely. 27 figs., 13 tabs., 59 refs

  20. The Hot Cell Radioactive Waste Concept of Forschungszentrum Juelich

    International Nuclear Information System (INIS)

    Pott, G.; Halaszovich, St.

    1999-01-01

    During the last 30 years extensive scientific examinations on radioactive metals,ceramics and fuel elements have been carried out, so that a high volume of waste has resulted. Also from the dismantling of irradiated facilities metallics waste has o be handed. Prior for equipment repair the hot cell involved has to be decontaminated and a large amount of lower active waste is produced. The waste is collected for conditioning and storing. There are different categories as: low active liquid waste, low active burnable waste, fuel waste, low and high active metallic waste. For each waste category special transport container are used. For the volume reduction our Waste Department is equipped with special facilities e.g.: furnace for burning, drying, liquids evaporators, hydraulic press for pelletizing, decontamination box for the dismantling ad cleaning of components. After conditioning the waste will be stored on site or transported to final storage in a salt mine (ERAM) . Special documentation has to be done for the acceptance of this waste

  1. Hot spots in nuclear and particle physics

    International Nuclear Information System (INIS)

    Stelte, N.

    1981-01-01

    The aim of the present thesis was the study of the phenomenon of the pre-equilibrium process in nuclear and particle physics in the framework of the HS picture. From the comparison of the HS model with inclusive experiments of nuclear physics it could be concluded, that HS's can have an important portion of the pre-equilibrium spectrum. In reactions of hadrons and lighter nuclei with heavy target nuclei the dependence of the HS-induced spectrum from the target mass, the detector angle, the kinetic energy, and as far as data were available, from the kind of the emitted particle as function of the drift parameter, the maximal temperature, and the velocity could be indicated. For forward angles a qualitative to quantitative agreement with the studied data could by shown. For backward angles a quantitative agreement resulted which suggests the conclusion that this angular range is determined by the HS effect even about three orders of magnitude of the incident energy. (orig./HSI) [de

  2. Solubility of hot fuel particles from Chernobyl--influencing parameters for individual radiation dose calculations.

    Science.gov (United States)

    Garger, Evgenii K; Meisenberg, Oliver; Odintsov, Oleksiy; Shynkarenko, Viktor; Tschiersch, Jochen

    2013-10-15

    Nuclear fuel particles of Chernobyl origin are carriers of increased radioactivity (hot particles) and are still present in the atmosphere of the Chernobyl exclusion zone. Workers in the zone may inhale these particles, which makes assessment necessary. The residence time in the lungs and the transfer in the blood of the inhaled radionuclides are crucial for inhalation dose assessment. Therefore, the dissolution of several kinds of nuclear fuel particles from air filters sampled in the Chernobyl exclusion zone was studied. For this purpose filter fragments with hot particles were submersed in simulated lung fluids (SLFs). The activities of the radionuclides (137)Cs, (90)Sr, (239+240)Pu and (241)Am were measured in the SLF and in the residuum of the fragments by radiometric methods after chemical treatment. Soluble fractions as well as dissolution rates of the nuclides were determined. The influence of the genesis of the hot particles, represented by the (137)Cs/(239+240)Pu ratio, on the availability of (137)Cs was demonstrated, whereas the dissolution of (90)Sr, (239+240)Pu and (241)Am proved to be independent of genesis. No difference in the dissolution of (137)Cs and (239+240)Pu was observed for the two applied types of SLF. Increased solubility was found for smaller hot particles. A two-component exponential model was used to describe the dissolution of the nuclides as a function of time. The results were applied for determining individual inhalation dose coefficients for the workers at the Chernobyl construction site. Greater dose coefficients for the respiratory tract and smaller coefficients for the other organs were calculated (compared to ICRP default values). The effective doses were in general lower for the considered radionuclides, for (241)Am even by one order of magnitude. © 2013 Elsevier B.V. All rights reserved.

  3. Confocal (micro)-XRF for 3D analysis of elements distribution in hot environmental particles

    International Nuclear Information System (INIS)

    Bielewski, M.; Eriksson, M.; Himbert, J.; Simon, R.; Betti, M.; Hamilton, T.F.

    2007-01-01

    Studies on the fate and transport of radioactive contaminates in the environment are often constrained by a lack of knowledge on the elemental distribution and general behavior of particulate bound radionuclides contained in hot particles. A number of hot particles were previously isolated from soil samples collected at former U.S. nuclear test sites in the Marshall Islands and characterized using non-destructive techniques [1]. The present investigation at HASYLAB is a part of larger research program at ITU regarding the characterization of environmental radioactive particles different locations and source-terms. Radioactive particles in the environment are formed under a number of different release scenarios and, as such, their physicochemical properties may provide a basis for identifying source-term specific contamination regimes. Consequently, studies on hot particles are not only important in terms of studying the elemental composition and geochemical behavior of hot particles but may also lead to advances in assessing the long-term impacts of radioactive contamination on the environment. Six particles isolated from soil samples collected at the Marshall Islands were studied. The element distribution in the particles was determined by confocal (micro)-XRF analysis using the ANKA FLUO beam line. The CRL (compound refractive lens) was used to focus the exciting beam and the polycapillary half lens to collimate the detector. The dimensions of confocal spot were measured by 'knife edge scanning' method with thin gold structure placed at Si wafer. The values of 3.1 x 1.4 x 18.4 (micro)m were achieved if defined as FWHMs of measured L?intensity profiles and when the19.1 keV exciting radiation was used. The collected XRF spectra were analyzed offline with AXIL [2] software to obtain net intensities of element characteristic lines.Further data processing and reconstruction of element distribution was done with the software 'R' [3] dedicated for statistical

  4. Calculating gamma dose factors for hot particle exposures

    International Nuclear Information System (INIS)

    Murphy, P.

    1990-01-01

    For hot particle exposures to the skin, the beta component of radiation delivers the majority of the dose. However, in order to fully demonstrate regulatory compliance, licenses must ordinarily provide reasonable bases for assuming that both the gamma component of the skin dose and the whole body doses are negligible. While beta dose factors are commonly available in the literature, gamma dose factors are not. This paper describes in detail a method by which gamma skin dose factors may be calculated using the Specific Gamma-ray Constant, even if the particle is not located directly on the skin. Two common hot particle exposure geometries are considered: first, a single square centimeter of skin lying at density thickness of 7 mg/cm 2 and then at 1000 mg/cm 2 . A table provides example gamma dose factors for a number of isotopes encountered at power reactors

  5. Safety distance for preventing hot particle ignition of building insulation materials

    OpenAIRE

    Jiayun Song; Supan Wang; Haixiang Chen

    2014-01-01

    Trajectories of flying hot particles were predicted in this work, and the temperatures during the movement were also calculated. Once the particle temperature decreased to the critical temperature for a hot particle to ignite building insulation materials, which was predicted by hot-spot ignition theory, the distance particle traveled was determined as the minimum safety distance for preventing the ignition of building insulation materials by hot particles. The results showed that for sphere ...

  6. Mechanism of Corrosion of Activated Aluminum Particles by Hot Water

    International Nuclear Information System (INIS)

    Razavi-Tousi, S.S.; Szpunar, J.A.

    2014-01-01

    Mechanism of corrosion in aluminum particles by hot water treatment for hydrogen generation is evaluated. The aluminum powder was activated by ball milling for different durations, which modified size and microstructure of the particles. Open circuit potential test was carried out to elucidate different stages of the reaction. Tafel test was used to explain the effect of ball milling and growth of hydroxide layer on corrosion of the particles. Surface, cross section and thickness of the grown hydroxide on the aluminum particles were studied in a scanning electron microscope. The corrosion potential of the aluminum powders depends on microstructure of the aluminum particles, growth of the hydroxide layer and a change in pH because of cathodic reactions. The hydrogen production test showed that a deformed microstructure and smaller particle size accelerates the corrosion rate of aluminum by hot water, the effect of the deformed microstructure being more significant at the beginning of the reaction. Effect of growth of the hydroxide layer on corrosion mechanism is discussed

  7. Development of Radioactive Substance Contamination Diffusion Preventive Equipment for a Hot cell

    International Nuclear Information System (INIS)

    Choo, Yong Sun; Kim, Do Sik; Baik, Seung Je; Yoo, Byung Ok; Kim, Ki Ha; Lee, Eun Pyo; Ahn, Sang Bok; Ryu, Woo Seok

    2009-01-01

    The hot cell of irradiated materials examination facility (IMEF), which has been operating since 1996, is generally contaminated by the radioactive nuclides of irradiated nuclear fuels and structural steels like Cs-137, Co-60, Co-134 and Ru-106. Especially Cs-137 is a main contaminated radioactive isotope which is easily moved here and there due to air flow in the hot cell, water-soluble, extremely toxic, and has a half-life of 30.23 years. To repair or fix the abnormal function of test apparatus installed in the hot cell, the maintenance door, so called a rear door and located at an intervention area, is opened to enter the hot cell inside. In a moment of opening the maintenance door, dirty air diffusion from the hot cell to an intervention area could be occurred in spite of increasing the rpm of exhaust fan to maintain much low under pressure, but an adjacent area to a maintenance door, i.e. intervention area, is very severely contaminated due to the unpredictable air flow. In this paper, the development of the radioactive substance contamination diffusion preventive equipment for a hot cell is studied to prevent dirty and toxic gaseous radioactive nuclides diffusion from a hot cell and installed at an intervention area of IMEF

  8. Effects of Hot Particles on the Skin: The Considerations of a EULEP/EURADOS Task Group (invited paper)

    International Nuclear Information System (INIS)

    Charles, M.W.; Burkhart, W.R.; Darley, P.J.; Hopewell, J.W.; Mill, A.J.

    2000-01-01

    The main findings are summarised of a recent joint EULEP/EURADOS working group (part of the Environmental Dosimetry Action of the EU 4th framework programme) which has reviewed the origins, physical and radiological characteristics, biological effects, and international dose limits for non respirable, radioactive 'hot particles' which present potential hazards to the skin. Account has been taken of previous deliberations of the ICRP, a recent draft report of the NCRP, recent statements from the US Nuclear Regulatory Commission (NRC), and other recent research findings regarding the stochastic effects of hot particle exposures. The working group recommends further research to address several topics which fall into four main areas: dosimetry: deterministic effects: stochastic effects: and radiological protection philosophy. The first three topics have been considered in three other papers in these proceedings. This paper concentrates on issues related to radiological protection philosophy which arise from the disparity between recommendations regarding hot particle dose limits of the ICRP, the NCRP and NRC. (author)

  9. Distribution Of Natural Radioactivity On Soil Size Particles

    International Nuclear Information System (INIS)

    Tran Van Luyen; Trinh Hoai Vinh; Thai Khac Dinh

    2008-01-01

    This report presents a distribution of natural radioactivity on different soil size particles, taken from one soil profile. On the results shows a range from 52% to 66% of natural radioisotopes such as 238 U, 232 Th, 226 Ra and 40 K concentrated on the soil particles below 40 micrometers in diameter size. The remained of natural radioisotopes were distributed on a soil particles with higher diameter size. The study is available for soil sample collected to natural radioactive analyze by gamma and alpha spectrometer methods. (author)

  10. Acute skin lesions due to localized ''hot particle'' radiation exposures

    International Nuclear Information System (INIS)

    Baum, J.W.; Carsten, A.L.; Kaurin, D.G.L.; Schaefer, C.W.

    1996-01-01

    Purpose of the studies was to determine incidence and severity of lesions resulting from localized deposition of dose to the skin from small ( 2 at 70μm depth) from isotopes having max beta particle energies from about 0.3-3 MeV. Incidence of erythema and scabs (indicating ulceration) were scored routinely for up to 71 days post-irradiation. Responses followed normal probability distributions, and thus, no true threshold could be defined. Ten and 50% incidence rates were deduced using probit analyses. Lowest dose producing 10% incidence was about 1 Gy for exposures to Yb-175 (0.5 MeV max energy) beta particles. Severity of lesions was estimated using diameters and persistence. From preliminary considerations of probability of induction, size, and persistence of acute lesions, a special limit for hot particle exposures in the range of 5-50 Gy may be reasonable, with an action level between about 1 Gy and the limit

  11. Particle transfer spectroscopy using radioactive targets

    CERN Document Server

    Naumann, R A

    1976-01-01

    The practicality of general use of radioactive targets to study nuclei off the stability line by transfer spectroscopy is examined. Some advantages of this spectroscopic technique are illustrated with recent results from (p, t) and (t, p) stable target studies of negative parity core-coupled states systematically occurring in 4 adjacent odd silver isotopes. Preliminary results from the study of the /sup 205/Pb (t, p)/sup 207/Pb reaction using reactor produced 3*10/sup 7/ year lead 205 are given. (3 refs).

  12. Radioactive particle resuspension research experiments on the Hanford Reservation

    International Nuclear Information System (INIS)

    Sehmel, G.A.

    1977-02-01

    Experiments were conducted from 1972 to 1975 at several Hanford Reservation study sites to determine whether radioactive particles from these sites were resuspended and transported by wind and to determine, if possible, any interrelationships between wind speed, direction, airborne soil, and levels of radioactivity on airborne particles. Samples of airborne particles were collected with high volume air samplers and cascade particle impactors using both upwind and downwind air sampling towers. Most samples were analyzed for 137 Cs; some samples were analyzed for 239 Pu, 238 Pu and 241 Am; a few samples were analyzed for 90 Sr. This report summarizes measured air concentration ranges for these radionuclides at the study sites and compares air concentrations with fallout levels measured in 300 Area near the Reservation boundary

  13. Effect of hot α-particles on ion cyclotron absorption

    International Nuclear Information System (INIS)

    Cairns, R.A.; Kay, A.; Lashmore-Davies, C.N.

    1987-01-01

    Ion cyclotron heating involves mode conversion of the incident fast wave to a Bernstein mode, which is generally stongly damped and only propagates in a localized region of the plasma. The usual theoretical approach to this problem involves solution of fourth or higher order equations, but by treating the Bernstein mode as a driven response to the fast wave we obtain a simple second order equation. Comparison of its solutions with those of higher order equations shows that this approach gives good results. The same method can be used to consider the effect of a small population of hot α-particles on ion cyclotron heating, since it does away with the need for a small larmor radius expansion. The results indicate that a small concentration of α-particles can absorb a substantial fraction of the incident energy

  14. Device for inserting and removing electric plug in socket- using remote handling apparatus inside radioactive hot cell

    International Nuclear Information System (INIS)

    Chevallereau, R.; Galmard, Y.

    1994-01-01

    A device for pushing an electric plug into a supply socket inside a radioactive hot cell and for withdrawing the plug after use of the appliance attached to it, comprises a pair of pivotally mounted arms. It can be used inside radioactive hot cells, to insert and put in and put off electric plugs

  15. Thermocouple placement and hot spots in radioactive waste tanks

    International Nuclear Information System (INIS)

    Barker, J.J.

    1991-06-01

    Analytical solutions available in Carslaw and Jaeger's Conduction of Heat in Solids for continuous point sources and for continuous finite sources are used to demonstrate that placement of thermocouples on a fine enough grid to detect a hot spot is impracticable for existing waste tanks but fortunately not necessary. Graphs covering ranges of diffusivities, times, temperatures and heat generation rates are included. 2 refs., 8 figs., 5 tabs

  16. Hot-melt extrusion for enhanced delivery of drug particles.

    Science.gov (United States)

    Miller, Dave A; McConville, Jason T; Yang, Wei; Williams, Robert O; McGinity, James W

    2007-02-01

    With the recent advent of nanotechnology for pharmaceutical applications, drug particle engineering is the focus of increasing interest as a viable approach for overcoming solubility limitations of poorly water-soluble drugs. Although these particle engineering techniques have been proven successful for enhancing the dissolution properties of many poorly water-soluble drugs, there are limitations associated with them such as particle aggregation, morphological instability, and poor wettability. The aim of this study was to demonstrate a processing technique in which hot-melt extrusion (HME) is utilized to overcome these limitations. Micronized particles of amorphous itraconazole (ITZ) stabilized with PVP or HPMC were produced and subsequently melt extruded with poloxamer 407 and PEO 200 M to deaggregate and disperse the particles into the hydrophilic polymer matrix. Differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy were used to demonstrate that the HME process did not alter the properties of the micronized particles. Dissolution testing conducted at sink conditions revealed that the dissolution rate of the micronized particles was improved by HME due to particle deaggregation and enhanced wetting. Supersaturation dissolution testing demonstrated that the ITZ-HPMC micronized particle extrudates provided superior supersaturation of ITZ compared to the ITZ-PVP micronized particle extrudates. Supersaturation dissolution testing incorporating a pH change (from pH 1.2 to 6.8 at 2 h) revealed that neither micronized particle extrudate formulation significantly reduced the rate of ITZ precipitation from supersaturated solution once pH was increased. Moreover, the two extrudate formulations performed very similarly when only considering dissolution testing from just before pH adjustment through the duration of testing at neutral pH. From oral dosing of rats, it was determined that the two extrudate formulations performed similarly in

  17. Safety distance for preventing hot particle ignition of building insulation materials

    Directory of Open Access Journals (Sweden)

    Jiayun Song

    2014-01-01

    Full Text Available Trajectories of flying hot particles were predicted in this work, and the temperatures during the movement were also calculated. Once the particle temperature decreased to the critical temperature for a hot particle to ignite building insulation materials, which was predicted by hot-spot ignition theory, the distance particle traveled was determined as the minimum safety distance for preventing the ignition of building insulation materials by hot particles. The results showed that for sphere aluminum particles with the same initial velocities and diameters, the horizontal and vertical distances traveled by particles with higher initial temperatures were higher. Smaller particles traveled farther when other conditions were the same. The critical temperature for an aluminum particle to ignite rigid polyurethane foam increased rapidly with the decrease of particle diameter. The horizontal and vertical safety distances were closely related to the initial temperature, diameter and initial velocity of particles. These results could help update the safety provision of firework display.

  18. A system for aerodynamically sizing ultrafine environmental radioactive particles

    International Nuclear Information System (INIS)

    Olawoyin, L.

    1995-09-01

    The unattached environmental radioactive particles/clusters, produced mainly by 222 Rn in indoor air, are usually few nanometers in size. The inhalation of these radioactive clusters can lead to deposition of radioactivity on the mucosal surface of the tracheobronchial tree. The ultimate size of the cluster together with the flow characteristics will determine the depositional site in the human lung and thus, the extent of damage that can be caused. Thus, there exists the need for the determination of the size of the radioactive clusters. However, the existing particle measuring device have low resolution in the sub-nanometer range. In this research, a system for the alternative detection and measurement of the size of particles/cluster in the less than 2 nm range have been developed. The system is a one stage impactor which has a solid state spectrometer as its impaction plate. It's major feature is the nozzle-to-plate separation, L. The particle size collected changes with L and thus, particle size spectroscopy is achieved by varying L. The number of collected particles is determined by alpha spectroscopy. The size-discriminating ability of the system was tested with laboratory generated radon particles and it was subsequently used to characterize the physical (size) changes associated with the interaction of radon progeny with water vapor and short chain alcohols in various support gases. The theory of both traditional and high velocity jet impactors together with the design and evaluation of the system developed in this study are discussed in various chapters of this dissertation. The major results obtained in the course of the study are also presented

  19. A system for aerodynamically sizing ultrafine environmental radioactive particles

    Energy Technology Data Exchange (ETDEWEB)

    Olawoyin, L.

    1995-09-01

    The unattached environmental radioactive particles/clusters, produced mainly by {sup 222}Rn in indoor air, are usually few nanometers in size. The inhalation of these radioactive clusters can lead to deposition of radioactivity on the mucosal surface of the tracheobronchial tree. The ultimate size of the cluster together with the flow characteristics will determine the depositional site in the human lung and thus, the extent of damage that can be caused. Thus, there exists the need for the determination of the size of the radioactive clusters. However, the existing particle measuring device have low resolution in the sub-nanometer range. In this research, a system for the alternative detection and measurement of the size of particles/cluster in the less than 2 nm range have been developed. The system is a one stage impactor which has a solid state spectrometer as its impaction plate. It`s major feature is the nozzle-to-plate separation, L. The particle size collected changes with L and thus, particle size spectroscopy is achieved by varying L. The number of collected particles is determined by alpha spectroscopy. The size-discriminating ability of the system was tested with laboratory generated radon particles and it was subsequently used to characterize the physical (size) changes associated with the interaction of radon progeny with water vapor and short chain alcohols in various support gases. The theory of both traditional and high velocity jet impactors together with the design and evaluation of the system developed in this study are discussed in various chapters of this dissertation. The major results obtained in the course of the study are also presented.

  20. Hot dewatering and resin encapsulation of intermediate level radioactive waste

    International Nuclear Information System (INIS)

    Rickman, J.; Birch, D.

    1985-01-01

    The chemistry of the processes involved in the hot dewatering and encapsulation of alumino-ferric hydroxide floc in epoxide resin have been studied. Pretreatment of the floc to reduce resin attack and hydrolysis and to increase the dimensional stability of the solidified wasteform has been evaluated. It has been demonstrated that removal of ammonium nitrate from the floc and control of the residual water in the resin are important factors in ensuring dimensional stability of the solidified resin. Resin systems have been identified which, together with the appropriate waste pretreatment have successfully encapsulated a simulated magnox sludge producing a stable wasteform having mechanical and physical properties comparable with the basic resin. (author)

  1. Characterization of radioactive particles from the Palomares accident

    International Nuclear Information System (INIS)

    Aragon, A.; Espinosa, A.; Cruz, B. de la; Fernandez, J.A.

    2008-01-01

    As a consequence of the nuclear accident that took place in Palomares (Almeria, Spain) more than 40 years ago, actinides contamination is present in the area nowadays. Previous investigations performed with soil samples collected in different locations of Palomares indicate that the contamination in the area is highly inhomogeneous, suggesting the existence of radioactive particles, thus hindering the evaluation of the radiological situation. This work presents the methodology used for the location of the radioactive particles in the field and their isolation in the laboratory for further speciation and characterization studies. Colour pictures, electron microscopy images and EDX analyses show that most of the studied particles present a granular appearance with a variable grain size and a high fragmentation tendency, being plutonium and uranium the most abundant nuclear elements. Radiochemical determinations and activity isotopic ratios prove that the nuclear material is aged weapon grade plutonium arising from the Palomares accident

  2. A software for computer automated radioactive particle tracking

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Wilson S.; Brandao, Luis E. [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)]. E-mails: wilson@ien.gov.br; brandao@ien.gov.br; Braz, Delson [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE)]. E-mail: delson@smb.lin.ufrj.br

    2008-07-01

    TRACO-1 is the first software developed in Brazil for optimization and diagnosis of multiphase chemical reactors employing the technique known as 'Computer Automated Radioactive Particle Tracking' whose main idea is to follow the movement of a punctual radioactive particle inside a vessel. Considering that this particle has a behavior similar of the phase under investigation, important conclusions can be achieved. As a preliminary TRACO-1 evaluation, a simulation was carried out with the aid of a commercial software called MICROSHIELD, version 5.05, to obtain values of photon counting rates at four detector surfaces. These counting were related to the emission of gamma radiation from a radioactive source because they are the main TRACO-1 input variables. Although the results that has been found are incipient, the analysis of them suggest that the tracking of a radioactive source using TRACO- 1 can be well succeed, but a better evaluation of the capabilities of this software will only be achieved after its application in real experiments. (author)

  3. A software for computer automated radioactive particle tracking

    International Nuclear Information System (INIS)

    Vieira, Wilson S.; Brandao, Luis E.; Braz, Delson

    2008-01-01

    TRACO-1 is the first software developed in Brazil for optimization and diagnosis of multiphase chemical reactors employing the technique known as 'Computer Automated Radioactive Particle Tracking' whose main idea is to follow the movement of a punctual radioactive particle inside a vessel. Considering that this particle has a behavior similar of the phase under investigation, important conclusions can be achieved. As a preliminary TRACO-1 evaluation, a simulation was carried out with the aid of a commercial software called MICROSHIELD, version 5.05, to obtain values of photon counting rates at four detector surfaces. These counting were related to the emission of gamma radiation from a radioactive source because they are the main TRACO-1 input variables. Although the results that has been found are incipient, the analysis of them suggest that the tracking of a radioactive source using TRACO- 1 can be well succeed, but a better evaluation of the capabilities of this software will only be achieved after its application in real experiments. (author)

  4. Natural radioactivity of bedrock bath instruments and hot spring instruments in Japan

    International Nuclear Information System (INIS)

    Kazuki Iwaoka; Hiroyuki Tabe; Hidenori Yonehara

    2013-01-01

    In Japan, bedrock bath instruments and hot spring instruments that contain natural radioactive nuclides are commercially available. In this study, such instruments containing natural radioactive nuclides, currently distributed in Japan, were collected and the radioactivity concentration of 238 U series, 232 Th series, and 40 K in them was determined by gamma ray spectrum analyses. Effective doses to workers and general consumers handling the materials were estimated, revealing the radioactivity concentration of 238 U series, 232 Th series, and 40 K to be lower than critical values given in the IAEA Safety Guide. The maximum effective doses to workers and general consumers were 210 and 6.1 μSv y -1 , respectively. These values are lower than the intervention exemption level (1,000 μSv y -1 ) given in ICRP Publ. 82. (author)

  5. Sampling of airborne radioactivity in a hot fuel examination facility

    International Nuclear Information System (INIS)

    Courtney, J.C.; Madison, J.P.; Holson, C.E.; Black, R.L.; Dilorenzo, F.L.; Anderson, J.B.; Hylsky, E.; Lau, L.D.

    1980-01-01

    To ensure the maintenance of a safe working environment, and provide data of interest to operations personnel, a fixed air sampling system (FASS) has been installed at the Hot Fuel Examination Facility/North at Argonne National Laboratory's Idaho site. A design requirement is that the system be operated with a minimum number of person-hours. Sixty-six sampling stations are located throughout the facility to gather data from areas where personnel are normally present without respiratory protection. The effectiveness of in-cell contamination-control programs and materials-handling procedures can be evaluated. Long-term trends are valuable guides to improving radiological controls while airborne activities are still well below operational guidelines. Since the beginning of operation in August 1976, the concentrations have averaged between 1x10 -15 and 5x10 -15 μCi/cm 3 for α emitters and from 4x10 -14 to 4x10 -13 μCi/cm 3 for β-γ emitters. Such values are well below the radiation concentration guides. (author)

  6. Radioactive Waste Decontamination Using Selentec Mag*SepSM Particles

    International Nuclear Information System (INIS)

    Walker, D.D.

    1998-01-01

    A sorbent containing crystalline silicotitanate (CST) tested for cesium removal from simulated Savannah River Site (SRS) soluble high activity waste showed rapid kinetics (1 h contact time) and high distribution coefficients (Kd 4000 mL/g of CST). The sorbent was prepared by Selective Environmental Technologies, Inc., (Selentec) as a MAG*SEP particle containing CST obtained from the Molecular Sieve Department of UOP, LLC, Results of preliminary tests suggest potential applications of the Selentec MAG*SEP particles to radioactive waste decontamination at SRS

  7. Radioactive particles in the environment: sources, particle characterization and analytical techniques

    International Nuclear Information System (INIS)

    2011-08-01

    Over the years, radioactive particles have been released to the environment from nuclear weapons testing and nuclear fuel cycle operations. However, measurements of environmental radioactivity and any associated assessments are often based on the average bulk mass or surface concentration, assuming that radionuclides are homogeneously distributed as simple ionic species. It has generally not been recognised that radioactive particles present in the environment often contain a significant fraction of the bulk sample activity, leading to sample heterogeneity problems and false and/or erratic measurement data. Moreover, the inherent differences in the transport and bioavailability of particle bound radionuclides compared with those existing as molecules or ions have largely been ignored in dose assessments. To date, most studies regarding radionuclide behaviour in the soil-plant system have dealt with soluble forms of radionuclides. When radionuclides are deposited in a less mobile form, or in case of a superposition of different physico-chemical forms, the behaviour of radionuclides becomes much more complicated and extra efforts are required to provide information about environmental status and behaviour of radioactive particles. There are currently no documents or international guides covering this aspect of environmental impact assessments. To fill this gap, between 2001 and 2008 the IAEA performed a Coordinated Research Programme (CRP- G4.10.03) on the 'Radiochemical, Chemical and Physical Characterization of Radioactive Particles in the Environment' with the objective of development, adoption and application of standardized analytical techniques for the comprehensive study of radioactive particles. The CRP was in line with the IAEA project intended to assist the Member States in building capacity for improving environmental assessments and for management of sites contaminated with radioactive particles. This IAEA-TECDOC presents the findings and achievements of

  8. The radiological significance of beta emitting hot particles released from the Chernobyl nuclear power plant

    International Nuclear Information System (INIS)

    Hofmann, W.; Crawford-Brown, D.J.; Martonen, T.B.

    1988-01-01

    In order to assess radiological hazards associated with inhalation of beta emitting hot particles detected in fall-out from the Chernobyl incident, radiation doses and lung cancer risk are calculated for a hot particle composed entirely of 103 Ru. Lung cancer risk estimates are based upon an initiation-promotion model of carcinogenesis. In the immediate vicinity of a hot particle, calculations indicate that doses may be extremely high, so that all cells are killed and no tumour will arise. At intermediate distances, however, the probability for lung cancer induction exhibits a distinct maximum. Risk enhancement factors, computed relative to a uniform radionuclide distribution of equal activity, are highest for intermediate activities and hot particles moving in the lung. While the risk from inhalation of 103 Ru hot particles might, indeed, exceed that from all other exposure pathways of the Chernobyl fall-out, it still lies within normal fluctuations of radon progeny induced lung cancer risk. (author)

  9. Enhanced removal of radioactive particles by fluorocarbon surfactant solutions

    International Nuclear Information System (INIS)

    Kaiser, R.; Harling, O.K.

    1993-08-01

    The proposed research addressed the application of ESI's particle removal process to the non-destructive decontamination of nuclear equipment. The cleaning medium used in this process is a solution of a high molecular weight fluorocarbon surfactant in an inert perfluorinated liquid which results in enhanced particle removal. The perfluorinated liquids of interest, which are recycled in the process, are nontoxic, nonflammable, and environmentally compatible, and do not present a hazard to the ozone layer. The information obtained in the Phase 1 program indicated that the proposed ESI process is technically effective and economically attractive. The fluorocarbon surfactant solutions used as working media in the ESI process survived exposure of up to 10 Mrad doses of gamma rays, and are considered sufficiently radiation resistant for the proposed process. Ultrasonic cleaning in perfluorinated surfactant solutions was found to be an effective method of removing radioactive iron (Fe 59) oxide particles from contaminated test pieces. Radioactive particles suspended in the process liquids could be quantitatively removed by filtration through a 0.1 um membrane filter. Projected economics indicate a pre-tax pay back time of 1 month for a commercial scale system

  10. Basic design and construction of a mobile hot cell for the conditioning of spent high activity radioactive sources

    International Nuclear Information System (INIS)

    An Hongxiang; Fan Zhiwen; Al-Mughrabi, M.

    2011-01-01

    The conditioning of spent high activity radioactive sources is one important step in sealed radioactive sources management strategies. Based on the practice on the designing of the immobilized hot cell, the handling of the sealed radioactive sources, and the reference of the mobile hot cell constructed in South Africa, SHARS conditioning process and the basic design of a mobile hot cell is developed. The mobile hot cell has been constructed and the tests including the cold test of the SRS conditioning, the hot cell assemble and disassemble and SRS recovery were done. The shielding capacity were tested by 3.8 x 10 13 Bq cobalt-60 sources and the dose rate of the equipment surface, below 2 m, is less than 0.016 mSv/h. It is proved that the designing requirement is meet and the function of the equipment is good. (authors)

  11. Handling of Highly Radioactive Radiation Sources in a Hot Cell Using a Mechanically Driven Cell Crane - 13452

    Energy Technology Data Exchange (ETDEWEB)

    Klute, Stefan; Huber, Wolfgang-Bruno [Siempelkamp Nukleartechnik GmbH, Am Taubenfeld 25/1, 69123 Heidelberg (Germany); Meyer, Franz [Nuclear Engineering Seibersdorf GmbH, 2444 Seibersdorf (Austria)

    2013-07-01

    In 2010, Siempelkamp Nukleartechnik GmbH was awarded the contract for design and erection of a Hot Cell for handling and storage of highly radioactive radiation sources. This Hot Cell is part of a new hot cell laboratory, constructed for the NHZ (Neues Handhabungszentrum = New Handling Center) of the Nuclear Engineering Seibersdorf GmbH (NES). All incurring radioactive materials from Austria are collected in the NHZ, where they are safely conditioned and stored temporarily until their final storage. The main tasks of the NES include, apart from the collection, conditioning and storage of radioactive waste, also the reprocessing and the decontamination of facilities and laboratories originating from 45 years of research and development at the Seibersdorf site as well as the operation of the Hot Cell Laboratory [1]. The new Hot Cell Laboratory inside the NHZ consists of the following room areas: - One hot cell, placed in the center, for remote controlled, radiation protected handling of radioactive materials, including an integrated floor storage for the long-term temporary storage of highly radioactive radiation sources; - An anteroom for the loading and unloading of the hot cell; - One control room for the remote controlling of the hot cell equipment; - One floor storage, placed laterally to the hot cell, for burial, interim storage and removal of fissionable radioactive material in leak-proof packed units in 100 l drums. The specific design activity of the hot cell of 1.85 Pbq relating to 1-Me-Radiator including the integrated floor storage influences realization and design of the components used in the cell significantly. (authors)

  12. Estimation of the sizes of hot nuclear systems from particle-particle large angle kinematical correlations

    International Nuclear Information System (INIS)

    La Ville, J.L.; Bizard, G.; Durand, D.; Jin, G.M.; Rosato, E.

    1990-06-01

    Light fragment emission, when triggered by large transverse momentum protons shows specific kinematical correlations due to recoil effects of the excited emitting source. Such effects have been observed in azimuthal angular distributions of He-particles produced in collisions induced by 94 MeV/u 16 0 ions on Al, Ni and Au targets. A model calculation assuming a two-stage mechanism (formation and sequential decay of a hot source) gives a good description of these whole data. From this succesfull confrontation, it is possible to estimate the size of the emitting system

  13. CR-39 α track detector and its application in observing of the hot particles in environment

    International Nuclear Information System (INIS)

    Zou Benchuan

    1992-01-01

    CR-39 α track detector is a new α remitting radionuclides plastic detector. It is audio-visual, convenient and economic in the detection of α particle track and the distribution of α emitting radionuclides in environmental samples. CR-39 α track detector is used to observe the hot particles in rock and the hot particles coming from the liquid effluents discharged by spent fuel reprocessing plant in UK in marine environment and got good results

  14. Biomineralization of radioactive sulfide minerals in strong acidic Tamagawa hot springs

    International Nuclear Information System (INIS)

    Tazaki, Kazue; Watanabe, Hiroaki

    2004-01-01

    Bioaccumulation of radioactive sulfide minerals by bacteria in strong acidic hot spring water was found at Tamagawa Hot Springs, Akita prefecture in Japan. The hot spring water produces Hokutolite of radioactive minerals high radium and radon. The β-ray measurements of sediments and biofilms indicate 1850-2420 and 5700 cpm, respectively, which are 50-100 times higher than that of the water and the air (50-90 cpm). The characteristics of hot spring water show pH (1.2), Eh (140 mV), EC (29 mS/cm), DO (0.8 mg/l), and water temperature (99.5degC), indicating extremely strong acidic and reducing conditions. The hot spring water contains mainly HCl associated with high concentrations of Ca 2+ , Al 3+ , Fe 2+ , HSO 4 - and SO 4 2- . SEM-EDX and TEM demonstrate some insight into how microorganisms affect the chemistry and microbiological characteristics of the strong acidic surroundings with high S, As, Ba, and Ca contents in biofilms. Especially SEM-EDX, ED-XRF, and STEM-EDX elemental content maps illustrate the distribution of sulfur-bearing compounds of barite (BaSO 4 ), gypsum (CaSO 4 ·2H 2 O), elemental sulfur (S) and orpiment(As 2 S 3 ) in the reddish orange biofilms. The presence of a hydrogen sulfide-rich (H 2 S) thermal spring and gypsum deposits suggest the volatilization of H 2 S from the spring water, oxidation of the H 2 S gas to sulfuric acid, and reaction of the sulfuric acid. TEM micrographs of bacteria in the biofilms reveal in detail the intimate connections between biological and mineralogical processes that the cells are entirely accumulated with spherical grains, 100∼200 nm in diameter. The relationship among sulfide minerals, such as barite, gypsum, sulfur, orpiment, and Hakutolite, associated with bacteria implies that heavy metals have been transported from strong acidic hot spring water to sediments through bacteria metabolism. It is possible that the capability of radioactive sulfide biofilms for heavy metal immobilization can be used to

  15. Hawking radiation of Dirac particles in the hot NUT-Kerr-Newman spacetime

    International Nuclear Information System (INIS)

    Ahmed, M.

    1991-01-01

    The Hawking radiation of charged Dirac particles on the horizons of the hot NUT-Kerr-Newman spacetime is studied in this paper. To this end, we obtain the radial decoupled Dirac equation for the electron in the hot NUT-Kerr-Newman spacetime. Next we solve the Dirac equation near the horizons. Finally, by analytic continuation, the Hawking thermal spectrum formula of Dirac particles is obtained. The problem of the Hawking evaporation of Dirac particles in the hot NUT-Kerr-Newman background is thus solved. (orig.)

  16. Synthesis and characterization of scandium oxide microspheres for their application in radioactive particle tracking experiments

    International Nuclear Information System (INIS)

    Goswami, Sunil; Biswal, Jayashree; Pant, H.J.; Pillai, K.T.; Bamankar, Y.R.

    2012-01-01

    Radioactive particle tracking (RPT) technique, proposed by Lin et al., is a noble technique for understanding mixing mechanisms of fluids and; evaluation and improvement of design of multiphase flow systems. In RPT technique the motion of a single radioactive particle is tracked in a flow system using an array of strategically mounted NaI(Tl) scintillation detectors around the system. The gamma emitting radioactive tracer particle being tracked is designed to be hydrodynamically similar to that of the phase being traced

  17. Influence of complex particle emission on properties of giant dipole resonance of hot nuclei

    International Nuclear Information System (INIS)

    Wen Wanxin; Jin Genming

    2003-01-01

    The possible reasons for the discrepancy between calculation results based on the statistical evaporation model and experimental data of giant dipole resonance of very hot nuclei are discussed. Both of simulations with the standard CASCADE code and the code coupling complex particle emission are carried out. It is shown that the complex particle emission affects the properties of giant dipole resonance of very hot nuclei

  18. Influence of radioactivity on surface charging and aggregation kinetics of particles in the atmosphere.

    Science.gov (United States)

    Kim, Yong-Ha; Yiacoumi, Sotira; Lee, Ida; McFarlane, Joanna; Tsouris, Costas

    2014-01-01

    Radioactivity can influence surface interactions, but its effects on particle aggregation kinetics have not been included in transport modeling of radioactive particles. In this research, experimental and theoretical studies have been performed to investigate the influence of radioactivity on surface charging and aggregation kinetics of radioactive particles in the atmosphere. Radioactivity-induced charging mechanisms have been investigated at the microscopic level, and heterogeneous surface potential caused by radioactivity is reported. The radioactivity-induced surface charging is highly influenced by several parameters, such as rate and type of radioactive decay. A population balance model, including interparticle forces, has been employed to study the effects of radioactivity on particle aggregation kinetics in air. It has been found that radioactivity can hinder aggregation of particles because of similar surface charging caused by the decay process. Experimental and theoretical studies provide useful insights into the understanding of transport characteristics of radioactive particles emitted from severe nuclear events, such as the recent accident of Fukushima or deliberate explosions of radiological devices.

  19. A radioactive particle detection system for the Maralinga rehabilitation project

    International Nuclear Information System (INIS)

    Martin, L.J.; Baylis, S.H.

    1998-01-01

    Following the cessation of British nuclear testing at Maralinga, several sites were left contaminated with plutonium in various forms over areas of many square kilometres. The contamination included 239 Pu and 241 Am together with other isotopes of plutonium, and was in the form of fine dust, discrete particles and contaminated fragments of metals, plastics and ceramics. Following a government decision to rehabilitate the area to a standard suitable for re-occupation by the traditional owners, the Maralinga Tjarutja, an expert committee, MARTAC, was convened to advise the Department of Primary Industries and Energy about suitable methods and standards for the cleanup. Criteria set by MARTAC required the removal of all discrete particles of contamination exceeding 100 kBq of 241 Am and imposed limits on the numbers of particles exceeding 20 kBq. A detection system was required which could detect any radioactive particles exceeding criteria and, following rehabilitation, verify that none remained. The most useful indicator of contamination was the 60 keV gamma-ray from 241 Am. The system was fitted to a four wheel drive utility vehicle, and was based on four thin-crystal, sodium iodide detectors of 12.5 cm diameter held 30 cm above ground level. Electronic components from off-the-shelf hand-held ratemeters were used to provide the high voltage supply, amplifier and single channel analyser in a ruggedised form of proven reliability. The combined use of thin crystal detectors and single channel analyser allowed a significant reduction in background count rates while maintaining the efficiency for detection of the 60 keV gamma-ray. To allow efficient and reliable coverage, the vehicle was fitted with a high-resolution speedometer to allow the proper speed to be maintained, and a mapping display, based on the GPS system, which showed the previous path of the vehicle and boundary of the area to be scanned. Whenever a radioactive particle was detected, its coordinates were

  20. A practical methodology of radiological protection for the reduction of hot particles in BWR type reactors; Una metodologia practica de proteccion radiologica para la reduccion de particulas calientes en reactores BWR

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez G, G [Comision Federal de Electricidad, Gerencia del Proyecto Nucleoelectrico Laguna Verde, Disciplina de Fisica Aplicada (Mexico)

    1991-07-01

    The purpose of this work, in general form, is to describe a practical method for reduction of hot particles generated as consequence of the operational activities of BWR nuclear reactors. This methodology provides a description of the localizations and/or probable activities of finding particles highly radioactive denominated hot particles. For this purpose it was developed a strategy based on the decontamination lineaments, as well as the manipulation, gathering, registration, contention, documentation, control and final disposition of the hot particles. In addition, some recommendations are reiterated and alternative, in order to gathering the hot particles in a dynamic way given to the activities of the personal occupationally exposed in highly radioactive areas. The structure of the methodology of hot particles is supported in the radiological controls based on the Code of Federal Regulation 10 CFR 20 as well as the applicable regulatory documents. It provides an idea based on administrative controls of radiological protection, in order to suggesting the responsibilities and necessary directing for the control of the hot particles required in nuclear plants of the BWR type. (author)

  1. Assessment of weathering and leaching rates of Thule hot particles

    Energy Technology Data Exchange (ETDEWEB)

    Roos, P. (Technical Univ. of Denmark, Risoe National Laboratory for Sustainable Energy, Roskilde (Denmark)); Outola, I. (STUK-Radiation and Nuclear Safety Authority (Finland)); Nygren, U.; Ramebaeck, H. (FOI CBRN Defence and Security (Sweden)); Sidhu, R. (Institute of Energy Technology, Environmental Monitoring Section, Health and Safety Dept. (Norway))

    2010-03-15

    Within the current project a methodology for separating actinide particles originating from the Thule 1968 accident has been developed. Particles were completely isolated in water using visual and radiometric methods. The particles were attached electrostatic to a plastic support and could easily be moved to any container for leaching studies or other type of studies. Leaching and dissolution studies performed within the project indicate that some particles are relatively easily destroyed or leached while others are more refractory. The results shows that even though the oxide particles are hard to completely dissolve they release material even when exposed to weak solvents like water and salt solutions. Exposures to lung simulant fluids show relatively slow dissolution rates comparable to what is found using only water. Sequential extraction of particles shows that variation between particles is very large; some dissolve easily while some does not. Of radiological importance is the disruption of particles when exposed to dissolution. (author)

  2. Assessment of weathering and leaching rates of Thule hot particles

    International Nuclear Information System (INIS)

    Roos, P.; Outola, I.; Nygren, U.; Ramebaeck, H.; Sidhu, R.

    2010-03-01

    Within the current project a methodology for separating actinide particles originating from the Thule 1968 accident has been developed. Particles were completely isolated in water using visual and radiometric methods. The particles were attached electrostatic to a plastic support and could easily be moved to any container for leaching studies or other type of studies. Leaching and dissolution studies performed within the project indicate that some particles are relatively easily destroyed or leached while others are more refractory. The results shows that even though the oxide particles are hard to completely dissolve they release material even when exposed to weak solvents like water and salt solutions. Exposures to lung simulant fluids show relatively slow dissolution rates comparable to what is found using only water. Sequential extraction of particles shows that variation between particles is very large; some dissolve easily while some does not. Of radiological importance is the disruption of particles when exposed to dissolution. (author)

  3. Challenges associated with the behaviour of radioactive particles in the environment.

    Science.gov (United States)

    Salbu, Brit; Kashparov, Valery; Lind, Ole Christian; Garcia-Tenorio, Rafael; Johansen, Mathew P; Child, David P; Roos, Per; Sancho, Carlos

    2018-06-01

    A series of different nuclear sources associated with the nuclear weapon and fuel cycles have contributed to the release of radioactive particles to the environment. Following nuclear weapon tests, safety tests, conventional destruction of weapons, reactor explosions and fires, a major fraction of released refractory radionuclides such as uranium (U) and plutonium (Pu) were present as entities ranging from sub microns to fragments. Furthermore, radioactive particles and colloids have been released from reprocessing facilities and civil reactors, from radioactive waste dumped at sea, and from NORM sites. Thus, whenever refractory radionuclides are released to the environment following nuclear events, radioactive particles should be expected. Results from many years of research have shown that particle characteristics such as elemental composition depend on the source, while characteristics such as particle size distribution, structure, and oxidation state influencing ecosystem transfer depend also on the release scenarios. When radioactive particles are deposited in the environment, weathering processes occur and associated radionuclides are subsequently mobilized, changing the apparent K d . Thus, particles retained in soils or sediments are unevenly distributed, and dissolution of radionuclides from particles may be partial. For areas affected by particle contamination, the inventories can therefore be underestimated, and impact and risk assessments may suffer from unacceptable large uncertainties if radioactive particles are ignored. To integrate radioactive particles into environmental impact assessments, key challenges include the linking of particle characteristics to specific sources, to ecosystem transfer, and to uptake and retention in biological systems. To elucidate these issues, the EC-funded COMET and RATE projects and the IAEA Coordinated Research Program on particles have revisited selected contaminated sites and archive samples. This COMET position

  4. Particle structure function and subbarrier fusion in hot nuclei

    International Nuclear Information System (INIS)

    Moretto, L.G.; Jing, K.X.; Phair, L.; Wozniak, G.J.

    1997-02-01

    The study of particle evaporation spectra can provide information about shape polarization phenomena induced by the nascent particle on the residual nucleus, and about optical modulations felt by the particle as it is preformed inside the nucleus. These aspects can be studied as a function temperature. Preliminary experimental evidence about these features has been obtained

  5. Challenges associated with the behaviour of radioactive particles in the environment

    DEFF Research Database (Denmark)

    Salbu, Brit; Kashparov, Valery; Lind, Ole Christian

    2018-01-01

    sites. Thus, whenever refractory radionuclides are released to the environment following nuclear events, radioactive particles should be expected. Results from many years of research have shown that particle characteristics such as elemental composition depend on the source, while characteristics...... on advanced techniques, with emphasis on particle weathering processes as well as on heterogeneities in biological samples to evaluate potential uptake and retention of radioactive particles.......A series of different nuclear sources associated with the nuclear weapon and fuel cycles have contributed to the release of radioactive particles to the environment. Following nuclear weapon tests, safety tests, conventional destruction of weapons, reactor explosions and fires, a major fraction...

  6. Radioactive Mapping Contaminant of Alpha on The Air in Space of Repair of Hot Cell and Medium Radioactivity Laboratory in Radio metallurgy Installation

    International Nuclear Information System (INIS)

    Yusuf-Nampira; Endang-Sukesi; S-Wahyuningsih; R-Budi-Santoso

    2007-01-01

    Hot cell and space of acid laboratory medium activity in Radio metallurgy Installation are used for the examination preparation of fuel nuclear post irradiation. The sample examined is dangerous radioactive material representing which can disseminate passing air stream. The dangerous material spreading can be pursued by arranging air stream from laboratory space to examination space. To know the performance the air stream arrangement is hence conducted by radioactive mapping contaminant of alpha in laboratory / space of activity place, for example, medium activity laboratory and repair space. This mapping radioactivity contaminant is executed with the measurement level of the radioactivity from sample air taken at various height with the distance of 1 m, various distance and from potential source as contaminant spreading access. The mapping result indicate that a little spreading of radioactive material happened from acid cupboard locker to laboratory activity up to distance of 3 m from acid cupboard locker and spreading of radioactive contaminant from goods access door of the hot cell 104 to repair space reach the distance of 2 m from goods door access. Level of the radioactive contamination in the space was far under maximum limitation allowed (20 Bq / m 3 ). (author)

  7. The development of a mobile hot cell facility for the conditioning of spent high activity radioactive sources

    International Nuclear Information System (INIS)

    Liebenberg, G.R.; Al-Mughrabi, M.

    2010-01-01

    The International Atomic Energy Agency (IAEA) Waste Technology Section with additional support from the U.S. National Nuclear Security Administration (NNSA) through the IAEA Nuclear Security Fund has funded the design, fabrication, evaluation, and testing of a portable hot cell intended to address the problem of disused Spent High Activity Radioactive Sources (SHARS) in obsolete irradiation devices such as teletherapy heads and dry irradiators. The project is initially targeting the African continent but expected soon to expand to Latin America and Asia. This hot cell allows source removal, characterization, consolidation, repackaging in modern storage shields, and secure storage of high risk SHARS at national radioactive waste storage facilities. (authors)

  8. Visualization study on hot particle-water interaction by using neutron radiography

    International Nuclear Information System (INIS)

    Mishima, K.; Hibiki, T.; Saito, Y.; Moriyama, Kiyofumi; Sugimoto, Jun

    1999-01-01

    In relation to severe accident research of a nuclear reactor, an experiment was performed to simulate the premixing process in the vapor explosion by dropping hot stainless-steel particle into heavy water filled in a rectangular tank. The test rig consisted of a furnace and a rectangular tank (400 mm in height, 100 mm in width and 30 mm in depth) filled with heavy water kept at 4degC. The particle diameter used in the experiment were 6, 9 and 12 mm, and the initial temperature of the particle ranged from 600 to 1000degC. The behavior of gas dome generated by heated particle-subcooled water interaction was successfully visualized by high-frame-rate neutron radiography at the recording speed of 500 frames/s. Temporal and spatial variations of void fraction in the gas dome were measured by processing the images obtained. The void fraction measurement indicated the possibility that the ambient fluid was superheated by the hot particle-water contact and the vapor was generated in proportion to the particle size and temperature. Preliminary calculations of heat transfer from hot particle to water were conducted by using and empirical correlation for steady film boiling. Comparison between experimental and calculated results suggested that the transient heat transfer around the hot particle could not be explained only by steady film boiling but some other heat transfer mechanisms such as unsteady film boiling or hear transfer due to direct contact may be needed. (author)

  9. Instantaneous axial velocity of a radioactive tracer determined with radioactive particle tracking

    Energy Technology Data Exchange (ETDEWEB)

    Fraguio, Maria Sol; Cassanello, Miryan C., E-mail: miryan@di.fcen.uba.a [Universidad de Buenos Aires (Argentina). Facultad de Ciencias Exactas y Naturales. Programa de Investigacion y Desarrollo de Fuentes Alternativas de Materias Primas y Energia (PINMATE); Cardona, Maria Angelica; Hojman, Daniel, E-mail: cardona@tandar.cnea.gov.a [CONICET, Buenos Aires (Argentina); Somacal, Hector [Comision Nacional de Energia Atomica (CNEA), Buenos Aires (Argentina). Centro Atomico Constituyentes. Dept. de Fisica

    2009-07-01

    Radioactive Particle Tracking (RPT) is a technique that has been successfully used to get features of the liquid and/or the solid motion in multiphase contactors. It is one of the rare techniques able to provide experimental data in dense and strongly turbulent multiphase media. Validation of the technique has always been based on comparing the estimated mean velocity to an imposed mean velocity although the extracted features are frequently related to the instantaneous velocities. The present work pursues the analysis, through calibration experiments, of the ability of RPT to get the actual tracer instantaneous velocities. With this purpose, the motion of a radioactive tracer attached to a moving rod driven by a pneumatic system is reconstructed from the combined response of an array of 10 NaI(Tl) scintillation detectors. Simultaneously, the tracer motion is registered through an encoder able to establish the axial tracer coordinate with high precision and high time resolution. The tracer is a gold particle, activated by neutron bombardment. The rod is moved at different velocities and it travels upwards and downwards close to the column centre. A mini-pilot scale bubble column is used as the test facility. The model liquid is tap water in batch mode and the gas is air, flowing at different gas velocities, spanning the homogeneous and the heterogeneous flow regimes. Time series of the entirety response of all the detectors, while the rod is moving at different imposed velocities within the two phase emulsion, are measured with a sampling period of 0.03 s during about 2 minutes. The instantaneous tracer positions and velocities reconstructed from RPT and the one obtained from the encoder response are compared under different operating conditions and for different tracer velocities. (author)

  10. In-vitro analysis of the dissolution kinetics and systemic availability of plutonium ingested in the form of 'hot' particles from the Semipalatinsk NTS.

    Science.gov (United States)

    Conway, M; León Vintró, L; Mitchell, P I; García-Tenorio, R; Jimenez-Ramos, M C; Burkitbayev, M; Priest, N D

    2009-05-01

    In-vitro leaching of radioactive 'hot' particles isolated from soils sampled at the Semipalatinsk Nuclear Test Site has been carried out in order to evaluate the fraction of plutonium activity released into simulated human stomach and small intestine fluids during digestion. Characterisation of the particles (10-100 Bq(239,240)Pu) and investigation of their dissolution kinetics in simulated fluids has been accomplished using a combination of high-resolution alpha-spectrometry, gamma-spectrometry and liquid scintillation counting. The results of these analyses indicate that plutonium transfer across the human gut following the ingestion of 'hot' particles can be up to two orders of magnitude lower than that expected for plutonium in a more soluble form, and show that for areas affected by local fallout, use of published ingestion dose coefficients, together with bulk radionuclide concentrations in soil, may lead to a considerable overestimation of systemic uptake via the ingestion pathway.

  11. In-vitro analysis of the dissolution kinetics and systemic availability of plutonium ingested in the form of 'hot' particles from the Semipalatinsk NTS

    Energy Technology Data Exchange (ETDEWEB)

    Conway, M. [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Leon Vintro, L. [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland)], E-mail: luis.leon@ucd.ie; Mitchell, P.I. [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Garcia-Tenorio, R.; Jimenez-Ramos, M.C. [Departamento de Fisica, Universidad de Sevilla, 41012 Sevilla (Spain); Burkitbayev, M. [Department of Inorganic Chemistry, Al-Farabi Kazakh National University, Almaty (Kazakhstan); Priest, N.D. [School of Health and Social Sciences, Middlesex University, Queensway, Enfield EN3 4SA (United Kingdom)

    2009-05-15

    In-vitro leaching of radioactive 'hot' particles isolated from soils sampled at the Semipalatinsk Nuclear Test Site has been carried out in order to evaluate the fraction of plutonium activity released into simulated human stomach and small intestine fluids during digestion. Characterisation of the particles (10-100 Bq {sup 239,240}Pu) and investigation of their dissolution kinetics in simulated fluids has been accomplished using a combination of high-resolution alpha-spectrometry, gamma-spectrometry and liquid scintillation counting. The results of these analyses indicate that plutonium transfer across the human gut following the ingestion of 'hot' particles can be up to two orders of magnitude lower than that expected for plutonium in a more soluble form, and show that for areas affected by local fallout, use of published ingestion dose coefficients, together with bulk radionuclide concentrations in soil, may lead to a considerable overestimation of systemic uptake via the ingestion pathway.

  12. Assessment of radiation dose formation due to hot particles of Chernobyl origin

    International Nuclear Information System (INIS)

    Demchuk, V.; Lutkovsky, V.; Bondarenko, O.

    1997-01-01

    The necessity to apply original data about the size and the activity distributions of hot particles has been arising at many post-Chernobyl research. Such researches include first of all (i) studying of migration processes at soil-water complexes, (ii) retrospective inhalation dose reconstruction for the population, and (iii) validation different scenarios of the Chernobyl accident deployment. Results of this research show that the fuel matrix in soil can be considered as constant with accuracy 20-30% for transuranic nuclides and major of long-living fission products. Temporal stability of hot particles at the natural environment gives a unique possibility to use the hot particle size distribution data and the soil contamination data for retrospective restoring of doses even 10 years later the Chernobyl accident. In present research the value of the integral of hot particle activity deposited into the lung was calculated using a standard inhalation model which takes into account the hot particle size distribution. This value normalised on the fallout density is equal to 0.55 Bq/(Bq.m -2 ) for areas nearby the Chernobyl NPP. (author)

  13. Vertical distribution of radioactive particles in Ottawa River sediment near the Chalk River Laboratories

    International Nuclear Information System (INIS)

    Lee, D.R.; Hartwig, D.S.

    2011-01-01

    Previously, we described an area of above-background levels of radioactivity in the bed of the Ottawa River near the Chalk River Laboratories. The area was about 200 m wide by 400 m long and in water 8 to 30 m deep. The source of the radioactivity was associated with the location of cooling-water discharge. Particles of radioactive material were later recovered from the upper 10-15 cm of sediment and were determined to be sand-sized grains of nuclear fuel and corrosion products. This report provides an examination of the vertical distribution of radioactive particles in the riverbed. Twenty-three dredge samples (representing 1.2 m 2 of riverbed) were collected near the Process Outfall. Each dredge sample was dissected in horizontal intervals 1-cm-thick. Each interval provided a 524 cm 3 sample of sediment that was carefully examined for particulate radioactivity. Approximately 80% of the radioactivity appeared to be associated with discrete particles. Although the natural sediment in the general area is cohesive, silty clay and contains less than 10% sand, the sediment near the Outfall was found to be rich in natural sand, presumably from sources such as winter sanding of roads at the laboratories. The radioactive particles were almost entirely contained in the top-most 10 cm of the river bed. The majority of the particles were found several centimetres beneath the sediment surface and the numbers of particles and the radioactivity of the particles peaked 3 to 7 cm below the sediment surface. Based on the sediment profile, there appeared to have been a marked decrease in the deposition of particulate radioactivity in recent decades. The vertical distribution of radioactive particles indicated that sedimentation is resulting in burial and that the deposition of most of the particulate radioactivity coincided with the operation of Chalk River's NRX reactor from 1947 to 1992. (author)

  14. Particle production in hot and dense nuclear matter

    International Nuclear Information System (INIS)

    Eklund, A.

    1992-08-01

    The charged particle production in heavy ion reactions at 200 A GeV has been studied for projectiles of 16 O and 32 S on targets of Al, Cu, Ag and Au. Up to 700 charged particles are measured in the pseudorapidity region -1.7 32 S+Au. The measured particle density is used to estimate the energy density attained in central collisions and gives a values of ≅2 GeV/fm 3 . This is close to the energy density predicted for the phase transition from hadronic matter to a quark-gluon plasma. To measure the large number of charged particle produced, finely granulated detector systems are employed. Streamer tube detectors with pad readout and large area, multi-step avalanche chambers with optical readout have been developed for the measurements. The widths of the pseudorapidity distributions of charged particles increase with decreasing centrality of the collision as well as with increasing mass of the target nucleus. This behaviour is assumed to be due to the target fragmentation. The Monte-Carlo model for nucleus-nucleus collisions, VENUS 3.11, which includes rescattering, is in reasonable agreement with the data. The yield of charged particles for central collisions of the heavy targets with 33 S is found to be proportional to the target mass, A, at target rapidity. At midrapidity it is approximately proportional to A 0.3 . At midrapidity the charged particle measurements are supplemented by measurements of the transverse energy. The dimensionless, normalized variances of the multiplicity and transverse energy distributions are, to a large extent, governed by the collision geometry. The change in the normalized variance when studying the charged particle distribution in a narrow angular region is explained as being of statistical nature. (au)

  15. Upper limits of α-radioactivity per particle of cigarette smoke

    International Nuclear Information System (INIS)

    Mogro-Campero, A.; Fleischer, R.L.

    1977-01-01

    Measurements of the α-activity per particle of tobacco smoke, which are necessary in evaluating the likelihood of radiation induced cancer from cigarette smoking, are reported. The results imply that each radioactive smoke particle must contain less than 2 x 10 -6 pCi of 210 Po or 1 x 10 -5 pCi of 210 Pb. From this it would appear that at most a few tobacco trichomes can be incorporated into one radioactive smoke particle. (U.K.)

  16. Overview of sources of radioactive particles of Nordic relevance as well as a short description of available particle characterisation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Lind, O.C.; Salbu, B. (Norwegian Univ. of Life Sciences (Norway)); Nygren, U.; Thaning, L.; Ramebaeck, H. (Swedish Defense Research Agency (FOI) (Sweden)); Sidhu, S. (Inst. for Energy Technology (Norway)); Roos, P. (Technical Univ. of Denmark. Risoe DTU, Roskilde (Denmark)); Poellaenen, R. (STUK (Finland)); Ranebo, Y.; Holm, E. (Univ. Lund (Sweden))

    2008-10-15

    The present overview report show that there are many existing and potential sources of radioactive particle contamination of relevance to the Nordic countries. Following their release, radioactive particles represent point sources of short- and long-term radioecological significance, and the failure to recognise their presence may lead to significant errors in the short- and long-term impact assessments related to radioactive contamination at a particular site. Thus, there is a need of knowledge with respect to the probability, quantity and expected impact of radioactive particle formation and release in case of specified potential nuclear events (e.g. reactor accident or nuclear terrorism). Furthermore, knowledge with respect to the particle characteristics influencing transport, ecosystem transfer and biological effects is important. In this respect, it should be noted that an IAEA coordinated research project was running from 2000-2006 (IAEA CRP, 2001) focussing on characterisation and environmental impact of radioactive particles, while a new IAEA CRP focussing on the biological effects of radioactive particles will be launched in 2008. (author)

  17. Overview of sources of radioactive particles of Nordic relevance as well as a short description of available particle characterisation techniques

    International Nuclear Information System (INIS)

    Lind, O.C.; Salbu, B.; Nygren, U.; Thaning, L.; Ramebaeck, H.; Sidhu, S.; Roos, P.; Poellaenen, R.; Ranebo, Y.; Holm, E.

    2008-10-01

    The present overview report show that there are many existing and potential sources of radioactive particle contamination of relevance to the Nordic countries. Following their release, radioactive particles represent point sources of short- and long-term radioecological significance, and the failure to recognise their presence may lead to significant errors in the short- and long-term impact assessments related to radioactive contamination at a particular site. Thus, there is a need of knowledge with respect to the probability, quantity and expected impact of radioactive particle formation and release in case of specified potential nuclear events (e.g. reactor accident or nuclear terrorism). Furthermore, knowledge with respect to the particle characteristics influencing transport, ecosystem transfer and biological effects is important. In this respect, it should be noted that an IAEA coordinated research project was running from 2000-2006 (IAEA CRP, 2001) focussing on characterisation and environmental impact of radioactive particles, while a new IAEA CRP focussing on the biological effects of radioactive particles will be launched in 2008. (au)

  18. Skin injuries from discrete radioactive particles: A summary of EPRI-sponsored experiments. Final report

    International Nuclear Information System (INIS)

    Owen, D.E.; Reece, W.D.; Poston, J.W. Sr.; McFarlane, D.L.

    1994-12-01

    In recent years there has been the debate over the risk to nuclear power plant workers from beta radiation-emitting discrete radioactive particles (or DRPs). DRPs-sometimes called open-quotes hot particlesclose quotes-are small, often microscopic, radioactive particles that can adhere to the skin and protective clothing of plant workers. They can potentially produce high radiation doses to very small areas of the skin. Concern is based on the knowledge that various types of nonstochastic skin injuries can result from sufficiently high beta radiation doses. While the effects for large-area irradiations (several square centimeters and larger) are generally well understood, the effects for doses to very small areas are less clear. However, the evidence is clear that the doses required to produce skin injuries from DRP irradiations are significantly larger than the dose limits prescribed in existing regulations for large-area skin exposures. One concern is that nuclear power plant efforts to comply with skin dose limits causes workers to receive unnecessary whole-body radiation exposure. In addition, DRP protection measures focus radiation protection resources on very low risk hazards, and may not be an optimum use of radiation protection resources. EPRI sponsored a series of irradiation experiments to address some of the DRP exposure issues. This report summarizes the results of experiments using sources covering a range of sizes and beta energies, simulating both activation product and fuel-bearing DRPS. NCRP Publication 106 states that all of these small skin injuries are minor, but that acute deep ulceration should be avoided. Accordingly, this research focused on open sores or scabs that remain unhealed for very long times. The ED 50 dose for these injuries was determined to be about 5 krad (50 Gy). A revised guideline might lower whole-body exposures associated with DRP control measures, while not significantly increasing the likelyhood of DRP injuries

  19. Hot particle dose calculations using the computer code VARSKIN Mod 2

    International Nuclear Information System (INIS)

    Durham, J.S.

    1991-01-01

    The only calculational model recognised by the Nuclear Regulatory Commission (NRC) for hot particle dosimetry is VARSKIN Mod 1. Because the code was designed to calculate skin dose from distributed skin contamination and not hot particles, it is assumed that the particle has no thickness and, therefore, that no self-absorption occurs within the source material. For low energy beta particles such as those emitted from 60 Co, a significant amount of self-shielding occurs in hot particles and VARSKIN Mod 1 overestimates the skin dose. In addition, the presence of protective clothing, which will reduce the calculated skin dose for both high and low energy beta emitters, is not modelled in VARSKIN Mod 1. Finally, there is no provision in VARSKIN Mod 1 to calculate the gamma contribution to skin dose from radionuclides that emit both beta and gamma radiation. The computer code VARSKIN Mod 1 has been modified to model three-dimensional sources, insertion of layers of protective clothing between the source and skin, and gamma dose from appropriate radionuclides. The new code, VARSKIN Mod 2, is described and the sensitivity of the calculated dose to source geometry, diameter, thickness, density, and protective clothing thickness are discussed. Finally, doses calculated using VARSKIN Mod 2 are compared to doses measured from hot particles found in nuclear power plants. (author)

  20. A temperature dependent cyclic plasticity model for hot work tool steel including particle coarsening

    Science.gov (United States)

    Jilg, Andreas; Seifert, Thomas

    2018-05-01

    Hot work tools are subjected to complex thermal and mechanical loads during hot forming processes. Locally, the stresses can exceed the material's yield strength in highly loaded areas as e.g. in small radii in die cavities. To sustain the high loads, the hot forming tools are typically made of martensitic hot work steels. While temperatures for annealing of the tool steels usually lie in the range between 400 and 600 °C, the steels may experience even higher temperatures during hot forming, resulting in softening of the material due to coarsening of strengthening particles. In this paper, a temperature dependent cyclic plasticity model for the martensitic hot work tool steel 1.2367 (X38CrMoV5-3) is presented that includes softening due to particle coarsening and that can be applied in finite-element calculations to assess the effect of softening on the thermomechanical fatigue life of hot work tools. To this end, a kinetic model for the evolution of the mean size of secondary carbides based on Ostwald ripening is coupled with a cyclic plasticity model with kinematic hardening. Mechanism-based relations are developed to describe the dependency of the mechanical properties on carbide size and temperature. The material properties of the mechanical and kinetic model are determined on the basis of tempering hardness curves as well as monotonic and cyclic tests.

  1. Accounting for the self-absorption of betas in cobalt-60 hot particles

    International Nuclear Information System (INIS)

    Lantz, M.W.; Steward, J.B.

    1988-01-01

    This paper reports that the assumptions used dose calculations can be overly conservative for discrete hot particles (activated satellite chips and irradiated fuel fragments) due to self-absorption of betas within the particles. Using data from tests with a Co-60 hot particle, a model is developed to estimate the dose reduction factor afforded by self-absorption in a satellite chip with a known thickness. The model can be applied indirectly using ion chamber survey instrument readings (the thickness of the particle does not have to be measured). Tests with Co-60 particles found at the Palo Verde Nuclear Generating Station verify that self-absorption is significant -- in one case, a dose reduction factor of 7 was measured in a satellite chip with a visible thickness

  2. Size measurement of radioactive aerosol particles in intense radiation fields using wire screens and imaging plates

    Energy Technology Data Exchange (ETDEWEB)

    Oki, Yuichi; Tanaka, Toru; Takamiya, Koichi; Ishi, Yoshihiro; UesugI, Tomonori; Kuriyama, Yasutoshi; Sakamoto, Masaaki; Ohtsuki, Tsutomu [Kyoto University Research Reactor Institute, Osaka (Japan); Nitta, Shinnosuke [Graduate School of Engineering, Kyoto University, Kyoto (Japan); Osada, Naoyuki [Advanced Science Research Center, Okayama University, Okayama (Japan)

    2016-09-15

    Very fine radiation-induced aerosol particles are produced in intense radiation fields, such as high-intensity accelerator rooms and containment vessels such as those in the Fukushima Daiichi nuclear power plant (FDNPP). Size measurement of the aerosol particles is very important for understanding the behavior of radioactive aerosols released in the FDNPP accident and radiation safety in high-energy accelerators. A combined technique using wire screens and imaging plates was developed for size measurement of fine radioactive aerosol particles smaller than 100 nm in diameter. This technique was applied to the radiation field of a proton accelerator room, in which radioactive atoms produced in air during machine operation are incorporated into radiation-induced aerosol particles. The size of 11C-bearing aerosol particles was analyzed using the wire screen technique in distinction from other positron emitters in combination with a radioactive decay analysis. The size distribution for 11C-bearing aerosol particles was found to be ca. 70 μm in geometric mean diameter. The size was similar to that for 7Be-bearing particles obtained by a Ge detector measurement, and was slightly larger than the number-based size distribution measured with a scanning mobility particle sizer. The particle size measuring method using wire screens and imaging plates was successfully applied to the fine aerosol particles produced in an intense radiation field of a proton accelerator. This technique is applicable to size measurement of radioactive aerosol particles produced in the intense radiation fields of radiation facilities.

  3. When hot particles are not on the skin

    International Nuclear Information System (INIS)

    Chabot, G.E.; Skrable, K.W.; French, C.S.

    1988-01-01

    In this paper a beta point source dose distribution function, cast in a form similar to that use in describing transmission of photons from point isotropic sources, is presented. The use of an apparent dose buildup factor and an effective value of the mass stopping power for beta distribution in the medium of interest allow the function to be applied in situations where the point source is in contact with the skin or separated from the skin by air or other energy absorbing materials. Example calculations are presented for a Co-60 particle on the skin (and compared to other methods) and for a Co-60 particle on protective clothing that is separated from the skin by an air gap

  4. Development of detection method for individual environmental particles containing alpha radioactive nuclides

    International Nuclear Information System (INIS)

    Esaka, Konomi; Yasuda, Kenichiro; Esaka, Fumitaka; Magara, Masaaki; Sakurai, Satoshi; Usuda, Shigekazu; Nakayama, Shinichi

    2006-01-01

    Artificial radioactive nuclides have been emitted from various sources and have fallen on the surface of the earth as fine particles. Although the characterization of the individual fallout particles is very important, their analysis is difficult. The purpose of this study is to develop a new detection method for individual objective particles containing radioactive nuclides in the environment. The soil or sediment sample was confined in a plastic film and the locations of objective particles were identified with alpha tracks created in a solid-state detectors (BARYOTRAK, Fukuvi Chemical, Ltd) stuck to the both sides of the plastic film. A piece of the film containing the objective particle was cut with a nitrogen laser for following individual particle analysis. This procedure allowed us to detect the objective particle from innumerable number of particles in the environment and characterize the individual particles. (author)

  5. Analysis of a Single Hot Particle by a Combination of Non-Destructive Analytical Methods

    Energy Technology Data Exchange (ETDEWEB)

    Hrnecek, E.; Aldave de las Heras, L.; Bielewski, M.; Carlos, R. [EC JRC Institute for Transuranium Elements, Karlsruhe (Germany); Betti, M. [IAEA Environment Laboratories (Monaco)

    2013-07-15

    Radioactive substances are often released to the environment in the form of particles. The determination of their chemical composition is a key factor in the overall understanding of their environmental behaviour. The aim of this investigation was to identify the source of one single radioactive particle collected from the Irish Sea and to understand its fate in the environment and in human body fluids. As the particle was supposed to be analysed for its dissolution behaviour in humans after ingestion, it was necessary to gain as much information as possible beforehand on the chemical and isotopic composition by means of non-destructive analysis such as SEM, SIMS, {mu}-XRF and {mu}-XANES. In this paper, an overview of the different non-destructive methods applied for the analysis of this particle and the results obtained is given. Additionally, the dissolution behaviour in human digestive solutions is discussed. (author)

  6. Point kernel technique for calculating dose rates due to cobalt-60 hot particles

    International Nuclear Information System (INIS)

    Thornhill, M.J.; McCarthy, J.T.; Morrissette, R.R.; Leach, B.N.

    1989-01-01

    This paper reports on a computer code called BETA that has been developed by health physicists at the Vermont Yankee Nuclear Power Station which accounts for the mass and size of hot particles of Cobalt-60, and therefore corrects the Loevinger-based dose calculation for self-absorption

  7. Overview of insoluble radioactive cesium particles emitted from the Fukushima Dai-ichi Nuclear Power Station

    Science.gov (United States)

    Satou, Yukihiko

    2017-04-01

    In the early stage of the Fukushima Dai-ichi Nuclear Power Station (F1NPS) accident, number of spot type contamination has been observed in computed autoradiography (Kashimura 2013, Shibata 2013, Satou 2014). It's means presence of radioactive particles, however, insoluble cesium particle was overlooked because cesium, which is dominant radioactive element in the accident, becomes ionized in the environment. Adachi et al. (2013) showed presence of cesium (Cs)-bearing particles within air dust sample collected at Tsukuba, 170 km south from the Fukushima site, in midnight of 14 to morning of 15 March 2011. These particles were micrometer order small particles and Cs was could be detectable as element using an energy dispersive X-ray spectroscopy (EDX). However, other radioactive elements such as Co-60, Ru-103 and uranium, which were dominant element of radioactive particles delivered from Chernobyl accident, could not detected. Abe et al. (2014) employed a synchrotron radiation (SR)-micro(μ)-X-ray analysis to the Cs-bearing particles, and they were concluded that (1) contained elements derived from nuclear fission processes and from nuclear reactor and fuel materials; (2) were amorphous; (3) were highly oxidized; and (4) consisted of glassy spherules formed from a molten mixture of nuclear fuel and reactor material. In addition, Satou et al. (2016) and Yamaguchi et al. (2016) disclosed that silicate is main component of Cs-bearing particles. Satou et al. (2015) discovered two types of radioactive particles from soil samples collected in the vicinity of the F1NPS. These particles were remained in the natural environment more than four years, silicate is main component in common of each group particles. Group A particles were very similar to Cs-bearing particles reported by Adachi et al. except particle shape. On the other hand, group B is big particles found in north area from the F1NPS, and the strongest particles contained 20 kBq of Cs-137 within a particle

  8. Retention of radioactive particles and associated effects in the filter-feeding marine mollusc Mytilus edulis

    Energy Technology Data Exchange (ETDEWEB)

    Jaeschke, B.C., E-mail: Ben.Jaeschke@gmail.com [Department of Ecology Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm (Sweden); CERAD CoE, Department of Environmental Sciences, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås (Norway); Lind, O.C. [CERAD CoE, Department of Environmental Sciences, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås (Norway); Bradshaw, C. [Department of Ecology Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm (Sweden); Salbu, B. [CERAD CoE, Department of Environmental Sciences, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås (Norway)

    2015-01-01

    Radioactive particles are aggregates of radioactive atoms that may contain significant activity concentrations. They have been released into the environment from nuclear weapons tests, and from accidents and effluents associated with the nuclear fuel cycle. Aquatic filter-feeders can capture and potentially retain radioactive particles, which could then provide concentrated doses to nearby tissues. This study experimentally investigated the retention and effects of radioactive particles in the blue mussel, Mytilus edulis. Spent fuel particles originating from the Dounreay nuclear establishment, and collected in the field, comprised a U and Al alloy containing fission products such as {sup 137}Cs and {sup 90}Sr/{sup 90}Y. Particles were introduced into mussels in suspension with plankton-food or through implantation in the extrapallial cavity. Of the particles introduced with food, 37% were retained for 70 h, and were found on the siphon or gills, with the notable exception of one particle that was ingested and found in the stomach. Particles not retained seemed to have been actively rejected and expelled by the mussels. The largest and most radioactive particle (estimated dose rate 3.18 ± 0.06 Gy h{sup −1}) induced a significant increase in Comet tail-DNA %. In one case this particle caused a large white mark (suggesting necrosis) in the mantle tissue with a simultaneous increase in micronucleus frequency observed in the haemolymph collected from the muscle, implying that non-targeted effects of radiation were induced by radiation from the retained particle. White marks found in the tissue were attributed to ionising radiation and physical irritation. The results indicate that current methods used for risk assessment, based upon the absorbed dose equivalent limit and estimating the “no-effect dose” are inadequate for radioactive particle exposures. Knowledge is lacking about the ecological implications of radioactive particles released into the environment

  9. Retention of radioactive particles and associated effects in the filter-feeding marine mollusc Mytilus edulis

    International Nuclear Information System (INIS)

    Jaeschke, B.C.; Lind, O.C.; Bradshaw, C.; Salbu, B.

    2015-01-01

    Radioactive particles are aggregates of radioactive atoms that may contain significant activity concentrations. They have been released into the environment from nuclear weapons tests, and from accidents and effluents associated with the nuclear fuel cycle. Aquatic filter-feeders can capture and potentially retain radioactive particles, which could then provide concentrated doses to nearby tissues. This study experimentally investigated the retention and effects of radioactive particles in the blue mussel, Mytilus edulis. Spent fuel particles originating from the Dounreay nuclear establishment, and collected in the field, comprised a U and Al alloy containing fission products such as 137 Cs and 90 Sr/ 90 Y. Particles were introduced into mussels in suspension with plankton-food or through implantation in the extrapallial cavity. Of the particles introduced with food, 37% were retained for 70 h, and were found on the siphon or gills, with the notable exception of one particle that was ingested and found in the stomach. Particles not retained seemed to have been actively rejected and expelled by the mussels. The largest and most radioactive particle (estimated dose rate 3.18 ± 0.06 Gy h −1 ) induced a significant increase in Comet tail-DNA %. In one case this particle caused a large white mark (suggesting necrosis) in the mantle tissue with a simultaneous increase in micronucleus frequency observed in the haemolymph collected from the muscle, implying that non-targeted effects of radiation were induced by radiation from the retained particle. White marks found in the tissue were attributed to ionising radiation and physical irritation. The results indicate that current methods used for risk assessment, based upon the absorbed dose equivalent limit and estimating the “no-effect dose” are inadequate for radioactive particle exposures. Knowledge is lacking about the ecological implications of radioactive particles released into the environment, for example

  10. Natural radionuclides in the environment. A contribution for the localization and characterization of natural hot particles in solid samples; Natuerliche Radionuklide in der Umwelt. Ein Beitrag zur Lokalisierung und Charakterisierung natuerlicher Heisser Teilchen in festen Proben

    Energy Technology Data Exchange (ETDEWEB)

    Boehnke, A.

    2006-07-01

    In the present thesis appearance, spreading, origin, and mineralogical properties of natural hot particles are studied and the radioecological relevance of these particles judged. For this first relevent quaestions on radioactivity in the environment and on hot particles are theoretically treated. In the following detailedly the method of the autoradiography and solid-state track detectors is considered, which make possible to quote the precise position, the number and distribution of radioactive particles on the cutting area or surface of a sample. Basing on these methodical considerations by laboratory experiments determined track pattern formations of alpha emitters are documentated and interpreted. Starting from the knowledge obtained from this in the further part of the thesis a detection technique is developed, by means of which it is possible, to determine and mark the position of natural hot particles in sold samples. Thereafter follows a description of the electron-microscopical studies for the identification of the localized natural hot particles. Using the developed detection technique, as well as the electron-microscopical methods, a broad spectrum of samples - anthropogeneous depositions (industrial residues, industry products, by-products) and natural depositions (rocks, sediments, minerals) - is studied.

  11. Proton beam shaped by “particle lens” formed by laser-driven hot electrons

    International Nuclear Information System (INIS)

    Zhai, S. H.; Shen, B. F.; Wang, W. P.; Zhang, H.; Zhang, L. G.; Huang, S.; Xu, Z. Z.; He, S. K.; Lu, F.; Zhang, F. Q.; Deng, Z. G.; Dong, K. G.; Wang, S. Y.; Zhou, K. N.; Xie, N.; Wang, X. D.; Liu, H. J.; Zhao, Z. Q.; Gu, Y. Q.; Zhang, B. H.

    2016-01-01

    Two-dimensional tailoring of a proton beam is realized by a “particle lens” in our experiment. A large quantity of electrons, generated by an intense femtosecond laser irradiating a polymer target, produces an electric field strong enough to change the trajectory and distribution of energetic protons flying through the electron area. The experiment shows that a strip pattern of the proton beam appears when hot electrons initially converge inside the plastic plate. Then the shape of the proton beam changes to a “fountain-like” pattern when these hot electrons diffuse after propagating a distance.

  12. Particle size of radioactive aerosols generated during machine operation in high-energy proton accelerators

    International Nuclear Information System (INIS)

    Oki, Yuichi; Kanda, Yukio; Kondo, Kenjiro; Endo, Akira

    2000-01-01

    In high-energy accelerators, non-radioactive aerosols are abundantly generated due to high radiation doses during machine operation. Under such a condition, radioactive atoms, which are produced through various nuclear reactions in the air of accelerator tunnels, form radioactive aerosols. These aerosols might be inhaled by workers who enter the tunnel just after the beam stop. Their particle size is very important information for estimation of internal exposure doses. In this work, focusing on typical radionuclides such as 7 Be and 24 Na, their particle size distributions are studied. An aluminum chamber was placed in the EP2 beam line of the 12-GeV proton synchrotron at High Energy Accelerator Research Organization (KEK). Aerosol-free air was introduced to the chamber, and aerosols formed in the chamber were sampled during machine operation. A screen-type diffusion battery was employed in the aerosol-size analysis. Assuming that the aerosols have log-normal size distributions, their size distributions were obtained from the radioactivity concentrations at the entrance and exit of the diffusion battery. Radioactivity of the aerosols was measured with Ge detector system, and concentrations of non-radioactive aerosols were obtained using condensation particle counter (CPC). The aerosol size (radius) for 7 Be and 24 Na was found to be 0.01-0.04 μm, and was always larger than that for non-radioactive aerosols. The concentration of non-radioactive aerosols was found to be 10 6 - 10 7 particles/cm 3 . The size for radioactive aerosols was much smaller than ordinary atmospheric aerosols. Internal doses due to inhalation of the radioactive aerosols were estimated, based on the respiratory tract model of ICRP Pub. 66. (author)

  13. Charging and coagulation of radioactive and nonradioactive particles in the atmosphere

    International Nuclear Information System (INIS)

    Kim, Yong-ha; Yiacoumi, Sotira

    2016-01-01

    Charging and coagulation influence one another and impact the particle charge and size distributions in the atmosphere. However, few investigations to date have focused on the coagulation kinetics of atmospheric particles accumulating charge. This study presents three approaches to include mutual effects of charging and coagulation on the microphysical evolution of atmospheric particles such as radioactive particles. The first approach employs ion balance, charge balance, and a bivariate population balance model (PBM) to comprehensively calculate both charge accumulation and coagulation rates of particles. The second approach involves a much simpler description of charging, and uses a monovariate PBM and subsequent effects of charge on particle coagulation. The third approach is further simplified assuming that particles instantaneously reach their steady-state charge distributions. It is found that compared to the other two approaches, the first approach can accurately predict time-dependent changes in the size and charge distributions of particles over a wide size range covering from the free molecule to continuum regimes. The other two approaches can reliably predict both charge accumulation and coagulation rates for particles larger than about 0.04 micrometers and atmospherically relevant conditions. These approaches are applied to investigate coagulation kinetics of particles accumulating charge in a radioactive neutralizer, the urban atmosphere, and an atmospheric system containing radioactive particles. Limitations of the approaches are discussed.

  14. Hydrodynamics of a commercial scale CFB boiler-study with radioactive tracer particles

    DEFF Research Database (Denmark)

    Lin, Weigang; Hansen, Peter F.B.; Dam-Johansen, Kim

    1999-01-01

    This paper presents the experimental results with radioactive tracer particles in an 80 MWth circulating fluidized-bed boiler. Batches of gamma-ray emitting tracer particles were injected into the standpipe. The response curves of the impulse injection were measured by a set of successive scintil...

  15. Apparatus using radioactive particles for measuring gas temperatures

    International Nuclear Information System (INIS)

    Compton, W.A.; Duffy, T.E.; Seegall, M.I.

    1975-01-01

    Apparatus for producing a signal indicative of the temperature of a heated gas is described comprising a beta particle source; a beta particle detector which intercepts particles emitted from said source; circuitry for converting the detector output to a signal indicative of the density of the gas; a pressure transducer for generating a signal indicative of the pressure on the gas; and circuitry for dividing the pressure signal by the density signal to produce a signal indicative of the average temperature of the gas along the path between the beta particle source and the beta particle detector. (auth)

  16. Lanthanide bearing radioactive particles for cancer therapy and multimodality imaging

    NARCIS (Netherlands)

    Zielhuis, S.W.

    2006-01-01

    Local radionuclide therapy using radioactive microspheres is a promising therapy for patients suffering from liver malignancies. In contrast to normal liver tissue, which receives most of its blood flow from the portal vein, liver malignancies are almost exclusively dependent on arterial blood

  17. Processes of conversion of a hot metal particle into aerogel through clusters

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, B. M., E-mail: bmsmirnov@gmail.com [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2015-10-15

    Processes are considered for conversion into a fractal structure of a hot metal micron-size particle that is located in a buffer gas or a gas flow and is heated by an external electric or electromagnetic source or by a plasma. The parameter of this heating is the particle temperature, which is the same in the entire particle volume because of its small size and high conductivity. Three processes determine the particle heat balance: particle radiation, evaporation of metal atoms from the particle surface, and heat transport to the surrounding gas due to its thermal conductivity. The particle heat balance is analyzed based on these processes, which are analogous to those for bulk metals with the small particle size, and its high temperature taken into account. Outside the particle, where the gas temperature is lower than on its surface, the formed metal vapor in a buffer gas flow is converted into clusters. Clusters grow as a result of coagulation until they become liquid, and then clusters form fractal aggregates if they are removed form the gas flow. Subsequently, associations of fractal aggregates join into a fractal structure. The rate of this process increases in medium electric fields, and the formed fractal structure has features of aerogels and fractal fibers. As a result of a chain of the above processes, a porous metal film may be manufactured for use as a filter or catalyst for gas flows.

  18. Protective clothing and hot particle control: EPRI workshop gives the issues an airing

    International Nuclear Information System (INIS)

    Owen, D.E.

    1990-01-01

    A recent workshop organized by the Electric Power Research Institute on Protective Clothing Topics and Hot Particle Control brought together working-level engineers, industry experts and vendors. Ideas arising from the accident recovery efforts at Three Mile Island were exchanged. Among the topics discussed were the role of fabric colour in the retention of radionuclides, modesty garments, laundering of protective clothing and worker heat stress. (author)

  19. Hot plasma and energetic particles in the earth's outer magnetosphere: new understandings during the IMS

    International Nuclear Information System (INIS)

    Baker, D.N.; Fritz, T.A.

    1984-01-01

    In this paper we review the major accomplishments made during the IMS period in clarifying magnetospheric particle variations in the region from roughly geostationary orbit altitudes into the deep magnetotail. We divide our review into three topic areas: (1) acceleration processes; (2) transport processes; and (3) loss processes. Many of the changes in hot plasmas and energetic particle populations are often found to be related intimately to geomagnetic storm and magnetospheric substorm effects and, therefore, substantial emphasis is given to these aspects of particle variations in this review. The IMS data, taken as a body, allow a reasonably unified view as one traces magnetospheric particles from their acceleration source through the plasma sheet and outer trapping regions and, finally, to their loss via ionospheric precipitation and ring current formation processes. It is this underlying, unifying theme which is pursued here. 52 references, 19 figures

  20. PIXE analysis of U and Pu from hot particles: K-lines vs L-lines

    DEFF Research Database (Denmark)

    Jiménez-Ramos, M.C.; García López, J.; Eriksson, M.

    2012-01-01

    . (2007) [1] and Jiménez-Ramos et al. (2010) [2], radioactive particles from aircraft accidents in Palomares and Thule have been characterized. Using micro-Proton Induced X-ray Emission (μ-PIXE) and confocal X-ray fluorescence microprobe (μ-XRF), the L-lines of the main components in these particles, U......-lines present not overlapping between the main peaks in the spectra and the X-ray absorption in the sample is much lower than for L-lines....

  1. New data on the self-absorption of betas in cobalt-60 hot particles

    International Nuclear Information System (INIS)

    Lantz, M.W.; Steward, J.B.

    1988-01-01

    The authors demonstrated that standard dose calculation methods for hot particles could seriously overestimate the beta dose rate component to skin. The reason-self-absorption within an activated satellite particle that has a finite thickness can lead to dramatic reductions in beta output, as compared to that predicted by calculation models that assume the particle has zero thickness. In this paper, the authors demonstrate the self-absorption effect with a particle model and confirmed it with measurements on two high-activity Co-60 particles found at the Palo Verde Nuclear Power Station. The authors then described a method for using an Eberline RO-2 ion chamber survey instrument to estimate the beta dose rate reduction related to self-absorption within a particle. This method relied on the comparison of the uncorrected beta/gamma ratio [(open window-closed window) divided-by closed window] for a particle expected of exhibiting self-absorption to the ratio obtained for a particle of zero thickness

  2. Monte Carlo Library Least Square (MCLLS) Method for Multiple Radioactive Particle Tracking in BPR

    Science.gov (United States)

    Wang, Zhijian; Lee, Kyoung; Gardner, Robin

    2010-03-01

    In This work, a new method of radioactive particles tracking is proposed. An accurate Detector Response Functions (DRF's) was developed from MCNP5 to generate library for NaI detectors with a significant speed-up factor of 200. This just make possible for the idea of MCLLS method which is used for locating and tracking the radioactive particle in a modular Pebble Bed Reactor (PBR) by searching minimum Chi-square values. The method was tested to work pretty good in our lab condition with a six 2" X 2" NaI detectors array only. This method was introduced in both forward and inverse ways. A single radioactive particle tracking system with three collimated 2" X 2" NaI detectors is used for benchmark purpose.

  3. Emanation of 232U and its radioactive daughter products from respirable size particles

    International Nuclear Information System (INIS)

    Cuddihy, R.G.; Griffith, W.C.; Hoover, M.D.; Kanapilly, G.M.; Stalnaker, N.D.

    1978-01-01

    This study is to develop a model for the emanation of 232 U and its radioactive daughter products from particles of Th-U fuel material. The radiation doses to internal organs following inhalation of these particles can only be calculated by knowing the rate of emanation of the daughters from particles in the lung and the subsequent excretion or translocation of the daughters to other organs. The emanation mechanisms are recoil of the daughter nuclei from the particle during alpha decay of the parent, diffusion of inert gas daughters from the particle and dissolution of the particle itself in biological fluids. Experiments to evaluate these mechanisms will involve ThO 2 and UO 2 particles in the size range 0.1 to 1.0 μm MMAD uniformly labeled with 232 U. The influence of the material temperature history on emanation will be investigated by heat treating particles at 600 and 1400 0 C

  4. Radioactive iodine (125I) labeling of latex particles

    International Nuclear Information System (INIS)

    Parikh, G.C.; Ho, C.K.

    1977-01-01

    The invention disclosed in this application is directed towards developing a radioiodination method which is applicable to the labeling of 2.02 micrometer (μm) and 0.37 micrometer (μm) diameter polyvinyltoluene latex particles that have been used as an immunoadsorbent. More particularly the overall method includes using an oxidation-reduction chemical reaction for tagging latex particles. Two methods are described. One, the hydrochloric acid method; and two, the nitric acid method

  5. Radioactive particles after different nuclear events in the USSR (overview and modern data)

    Energy Technology Data Exchange (ETDEWEB)

    Gordeev, S.K.; Stukin, E.D.; Kvasnikova, E.V. [Institute of Global Climate and Ecology, Moscow (Russian Federation)

    2004-07-01

    Institute of Global Climate and Ecology participated in all stages of investigations concerning spreading of the radioactive particles formed after nuclear explosions. Since 1963 the radioactive particles from the surface nuclear explosions on the Semipalatinsk Test Site were investigated. Since 1964 the study of the environmental contamination from the underground nuclear explosions (including the cratering nuclear explosions) was carried out. Simultaneously the secondary radioactive aerosols released into the atmosphere from ventilated underground explosions were investigated. Since 1986 the forming and spreading of the radioactive aerosols from Chernobyl accident was studied. An overview of retrospective data will be presented. For example, the fragmentation radionuclides {sup 90}Sr, {sup 137}Cs and {sup 155}Eu, radionuclides induced by neutrons {sup 60}Co, {sup 152}Eu, {sup 154}Eu and transuranium radionuclides {sup 238}Pu, {sup 239+240}Pu and {sup 241}Am were estimated in 15 particles of August, 29, 1949 explosion using the semiconductor spectrometry and radiochemical analysis. Data collection include the samples taken on local traces of ground and underground excavation nuclear explosions, this information will be added by the modern data from soil samples near '1004' explosion (lake Chagan), October 2003. The results of comparison of radionuclide fractionation in the radioactive particles in slag from cratering nuclear explosions and in melt samples will be presented. Main results obtained under the IAEA Research Contract no. 11468. (author)

  6. General decay law for emission of charged particles and exotic cluster radioactivity

    International Nuclear Information System (INIS)

    Sahu, Basudeb; Paira, Ramkrishna; Rath, Biswanath

    2013-01-01

    For the emission of charged particles from metastable nuclei, a general decay formula is developed based on the basic phenomenon of resonances occurring in quantum scattering process under Coulomb-nuclear potential. It relates the half-lives of monopole radioactive decays with the Q-values of the outgoing elements in different angular momentum states as well as the masses and charges of the nuclei involved in the decay. The relation is found to be a generalization of the Geiger–Nuttall law in α radioactivity and it explains well all known emission of charged particles including clusters, alpha and proton carrying angular momenta

  7. Too hot to handle. Social and policy issues in the management of radioactive wastes

    International Nuclear Information System (INIS)

    Walker, C.A.; Gould, L.C.; Woodhouse, E.J.

    1983-01-01

    Information about the management of radioactive wastes is provided in this book. Specifically, the book attempts to supply information to further the understanding of the history of radioactive waste management in this country and the role of nuclear energy in the future of the US; the science and technology of the processes that produce radioactive wastes and of the methods proposed for managing them; the biological effects of radiation; the public attitudes about nuclear power; the nature of risks resulting from technological developments and ways of managing them; and the political institutions and processes that govern radioactive waste management. The authors have attempted to present an objective view of nuclear waste management taking a stand neither for nor against nuclear power but placing special emphasis on radioactive waste management rather than nuclear power, because they feel that the latter aspect of the subject has received much more extensive coverage elsewhere. The contents of the book are divided into 7 chapters entitled: The Radioactive Waste Management Problem, Science and Technology of the Sources and Management of Radioactive Wastes, Nuclear Waste Management and Risks to Human Health, Public Attitudes toward Radioactive Wastes, How Safe Is Safe Enough; Determinants of Perceived and Acceptable Risk, The Politics of Nuclear Waste Management, and Value Issues in Radioactive Waste Management

  8. Peculiarities of the radioactive particles transport phenomena in the facilitated diffusion processes

    International Nuclear Information System (INIS)

    Gavryushenko, D.A.; Sisojev, V.M.; Cherevko, K.V.; Vlasenko, T.S.

    2017-01-01

    The work is devoted to the up to date problem that is the description of the radioactive particle diffusion processes. One of the aims of the present study is to estimate the effects caused by the irradiation of the liquid systems on the ongoing transport processes. That can allow predicting the behavior of the liquid systems in the presence of the radioactive sources. The main objective of the present work is studying the radioactive particles diffusion phenomena with the possible facilitated diffusion processes being considered. The phenomena are studied based on the fundamental relations of the nonequilibrium statistical thermodynamics. The diffusive flows are evaluated with the special attention given to the accounting of the entropy effects due to the appearance of the new radioactive particles in the system. The developed approach is used to estimate the diffusive flow of the radioactive particles for the case of the plane-parallel pore with the semi-transparent walls. The choice of a model can be justified as it might be used to describe the production of the radioactive contaminated water when the radionuclide face the diffusion process after being washed from the radioactive wastes and the rests of the nuclear fuel. Within the suggested model it is shown that the diffusion coefficient depends on the structural properties of the liquid systems that might be changed under the influence of the irradiation. The obtained equations for calculating the diffusive flows show the definite stabilizing effect in respect to the concentration difference in between the boundaries of the plane-parallel pore. It leads to the decreased changes of the diffusive flow when the concentrations of the radioactive particles at the boundaries are changed in comparison with those observed for the constant diffusion coefficient. The observed behavior for the ideal solution model is explained by the entropy effects. The qualitative analysis of the possible influence of the changes in

  9. The optimization of treatment with radioactive iodine (131I) of the hypersecretive ''hot'' tumors of the thyroid

    International Nuclear Information System (INIS)

    Gorowski, T.; Zgliczynski, S.

    1987-01-01

    The studies have been carried out in 50 patients with hyperthyroidism associated with the presence of ''hot'' thyroid tumor. The effectiveness of treatment with a standard dose of radioactive iodine, a dose which after 48 hours following the administration caused an appearance of 5.55 MBq (150 μCi) of 131 I in 1 cubic centimeter of the tumor, has been determined. In each case the condition of the patient was evaluated several times before and after the treatment, basing on clinical examination, scintigraphy of the thyroid, the determinations of T 3 , T 4 and TSH concentrations and, when needed, also the determination of TSH after stimulation with TRH. The period of observation after the administration of the first therapeutic dose of radioactive iodine was between 2 and 19 years (mean 6.5 years). The results obtained indicated that in 40 among 50 patients (80%) hyperthyroidism disappeared after administration of a single dose of radioactive iodine calculated as specified above. In two of these patients (4%) hypothyroidism resulted. In the remaining 10 patients (20%) the treatment with radioactive iodine had to be repeated. This resulted in disappearance of hyperthyroidism also in these 10 patients, bringing the total amount of cured patients to 50 (100%), and increasing the amount of patients with hypothyroidism to barely 3 cases (6%). 23 refs., 2 tabs. (author)

  10. Biological monitoring of the deposition and transport of radioactive aerosol particles in the Chernobyl NPP zone of influence

    International Nuclear Information System (INIS)

    Viktorova, N.V.; Garger, E.K.

    1991-01-01

    Plants are one of the main links in the trophic chains of radionuclide transport. The role of plants in such transport was studied mainly in relation to soluble compounds of radionuclides, or to global fallout in which radionuclides were in soluble or exchangeable forms. The specifics of the Chernobyl accident led to the radioactivity occurring in particular forms, and the kinetics of radionuclide migration within trophic chains sometimes vary considerably from what was established in earlier experiments. It is important to study the interaction between plants and ''hot particles'', whose physico-chemical properties determine their non-solubility, which is characteristic, for example, of the carbides and oxides of some metals. When particles come into contact with plant surface tissues, ''dissolving'' factors come into play such as changes in the acidity of the solution or interaction with complex-forming compounds and organic materials exuded by the leaves of some plants. Thanks to these factors, many plants are capable of extracting compounds of low solubility from the soil minerals. Making use of macro- and micro-radioautography, we set out to estimate the rate of conversion of low-solubility radionuclide particles into biologically mobile forms of radionuclides accessible to plants; to study the density of fuel particle fallout in the near-ground layer of the atmosphere and to assess how this varies at different distances from the fallout source over time (during the four years following the accident, 1986-1989); to study the size of the particles deposited on the leaves of plants at various strata, their activity, morphology and behaviour when kept in the form of herbarium exhibits; and to assess the contribution of alpha-active particles to the general amount of fallout and how it changes over time. (author)

  11. Reassessment of data used in setting exposure limits for hot particles

    International Nuclear Information System (INIS)

    Baum, J.W.; Kaurin, D.G.

    1991-05-01

    A critical review and a reassessment of data reviewed in NCRP Report 106 on effects of ''hot particles'' on the skin of pigs, monkeys, and humans were made. Our analysis of the data of Forbes and Mikhail on effects from activated UC 2 particles, ranging in diameter from 144 μm to 328 μm, led to the formulation of a new model for prediction of both the threshold for acute ulceration and for ulcer diameter. A dose of 27 Gy at a depth of 1.33 mm in tissue in this model will result in an acute ulcer with a diameter determined by the radius over which this dose (at 1.33-mm depth) extends. Application of the model to the Forbes-Mikhail data yielded a ''threshold'' (5% probability) of 6 x 10 9 beta particles from a point source on skin of mixed fission product beta particles, or about 10 10 beta particles from Sr--Y-90, since few of the Sr-90 beta particles reach this depth. The data of Hopewell et al. for their 1 mm Sr-Y-90 exposures were also analyzed with the above model and yielded a predicted threshold of 2 x 10 10 Sr-Y-90 beta particles for a point source on skin. Dosimetry values were employed in this latter analysis that are 3.3 times higher than previously reported for this source. An alternate interpretation of the Forbes and Mikhail data, derived from linear plots of the data, is that the threshold depends strongly on particle size with the smaller particles yielding a much lower threshold and smaller minimum size ulcer. Additional animal exposures are planned to distinguish between the above explanations. 17 refs., 3 figs., 3 tabs

  12. Study of the magnetic compressional mode in a hot particle plasma

    International Nuclear Information System (INIS)

    Stotler, D.P.; Berk, H.L.; Engquist, M.G.

    1985-09-01

    The integral equation for the magnetic compressional mode, accounting for geometrical effects along the field line and using the eikonal approximation across the field line, is solved numerically for the eigenvalues and eigenfunctions. These results reproduce the analytic estimates when there is strong drift reversal. For typical EBT-S parameters, instability is observed for all pressure scale lengths just below those needed for drift reversal, i.e., vertical bar Rpar. delta(P/sub c/ + P/sub perpendicular h/)/2B 2 par. deltar vertical bar > 1 (where P is the particle pressure, c and h refer to cold and hot components, B is the midplane magnetic field, and R is the midplane radius of curvature). If larger core densities are present, a wave-particle resonance arises when the particle drifts are not reversed, causing instability up to much larger pressure scale lengths. Stability for all values of the ratio of hot electron density to core density is obtained with vertical bar Rpar. deltaP/sub c//B 2 par. deltar vertical bar > 1 + P/sub parallel h//P/sub perpendicular h/

  13. Source apportionment of aerosol particles at a European air pollution hot spot using particle number size distributions and chemical composition.

    Science.gov (United States)

    Leoni, Cecilia; Pokorná, Petra; Hovorka, Jan; Masiol, Mauro; Topinka, Jan; Zhao, Yongjing; Křůmal, Kamil; Cliff, Steven; Mikuška, Pavel; Hopke, Philip K

    2018-03-01

    Ostrava in the Moravian-Silesian region (Czech Republic) is a European air pollution hot spot for airborne particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), and ultrafine particles (UFPs). Air pollution source apportionment is essential for implementation of successful abatement strategies. UFPs or nanoparticles of diameter hot-spot including nanoparticles, Positive Matrix Factorization (PMF) was applied to highly time resolved particle number size distributions (NSD, 14 nm-10 μm) and PM 0.09-1.15 chemical composition. Diurnal patterns, meteorological variables, gaseous pollutants, organic markers, and associations between the NSD factors and chemical composition factors were used to identify the pollution sources. The PMF on the NSD reveals two factors in the ultrafine size range: industrial UFPs (28%, number mode diameter - NMD 45 nm), industrial/fresh road traffic nanoparticles (26%, NMD 26 nm); three factors in the accumulation size range: urban background (24%, NMD 93 nm), coal burning (14%, volume mode diameter - VMD 0.5 μm), regional pollution (3%, VMD 0.8 μm) and one factor in the coarse size range: industrial coarse particles/road dust (2%, VMD 5 μm). The PMF analysis of PM 0.09-1.15 revealed four factors: SIA/CC/BB (52%), road dust (18%), sinter/steel (16%), iron production (16%). The factors in the ultrafine size range resolved with NSD have a positive correlation with sinter/steel production and iron production factors resolved with chemical composition. Coal combustion factor resolved with NSD has moderate correlation with SIA/CC/BB factor. The organic markers homohopanes correlate with coal combustion and the levoglucosan correlates with urban background. The PMF applications to NSD and chemical composition datasets are complementary. PAHs in PM 1 were found to be associated with coal combustion factor. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Animal experiment on 188Re-radioactive nanometre particle esophageal stent

    International Nuclear Information System (INIS)

    Chu Jianjun; Yang Bo; Zhao Difei; Wang Mingzhi; Sun Liang; Jiang Wei

    2004-01-01

    Objective: To investigate the mechanism and clinical reliability of applying 188 Re-radioactive nanometre particle esophageal stent. Methods: An elastic meshed esophageal stent made of double membranous nickel-titanium alloy and loaded with 188 Re-radioactive nanometre particles was used . The stent was introduced into the esophagus of eight experimental pigs and fixed in place. Two pigs served as controls. With the pig aneasthetized, the stent with good expandability was placed in the proper position. Radioactive MBq was applied to the 8 experiment pigs while the two control pigs received only the stent without the radioactive material. Three hours after the insertion of the stent, the pigs were allowed to feed, without any choking observed. Results: Seven days after the treatment of pathologic experiment pigs showed infla mmatory celluar infilfration, congestion and edema in the mucosa and submucous layer. After 21 days, some parts of the esophageal mucosa showed thickening of the vascular layer of the blood vessels and scanty fibrous hyperplasia. Seven days after application of larger dose of 259 MBq stent, pathology examination carried out in the experiment pigs showed extensive infla mmatory cellular infilfration, edema and congestion in the muscles and submucosa, and patch-like necrosis. Twenty-one days after application, repairing fibrous hyperplasia appeared. In the control pigs, not even any traumatic damage was observed. Periodic checking of the stool did not show any leakage of radioactivity and there was no displacement of the stents as confirmed by X-ray exam. Conclusions: The stent is effective to maintain an unobstructed passage of food . The loaded radioactive particles can be concentrated in the target area and adjusted by a body surface magnetic modulation and inhibit the intraluminal epithelial growth of esophageal mucosa without any severe radiation reaction or damage. It is quite promising to resolve the obstruction of advanced esophageal

  15. Particle size distributions of radioactive aerosols measured in workplaces

    International Nuclear Information System (INIS)

    Dorrian, M.-D.; Bailey, M.R.

    1995-01-01

    A survey of published values of Activity Median Aerodynamic Diameter (AMAD) measured in working environments was conducted to assist in the selection of a realistic default AMAD for occupational exposures. Results were compiled from 52 publications covering a wide variety of industries and workplaces. Reported values of AMAD from all studies ranged from 0.12 μm to 25 μm, and most were well fitted by a log-normal distribution with a median value of 4.4 μm. This supports the choice of a 5 μm default AMAD, as a realistic rounded value for occupational exposures, by the ICRP Task Group on Human Respiratory Tract Models for Radiological Protection and its acceptance by ICRP. Both the nuclear power and nuclear fuel handling industries gave median values of approximately 4 μm. Uranium mills gave a median value of 6.8 μm with AMADs frequently greater than 10 μm. High temperature and arc saw cutting operations generated submicron particles and occasionally, biomodal log-normal particle size distributions. It is concluded that in view of the wide range of AMADs found in the surveyed literature, greater emphasis should be placed on air sampling to characterise aerosol particle size distributions for individual work practices, especially as doses estimated with the new 5 μm default AMAD will not always be conservative. (author)

  16. alpha-particle radioactivity from LR 115 by two methods of analysis

    CERN Document Server

    Azkour, K; Adloff, J C; Pape, A

    1999-01-01

    LR115 track detectors were exposed to samples of Moroccan phosphate and phosphogypsum to measure their alpha-particle radioactivity. Then two formalisms were used for the dosimetry: simulation by a Monte Carlo method and determination of concentrations from a numerically integrated track registration equation. The results were compared with those deduced gamma-ray spectrometry.

  17. Remarkable morphological diversity of viruses and virus-like particles in hot terrestrial environments.

    Science.gov (United States)

    Rachel, R; Bettstetter, M; Hedlund, B P; Häring, M; Kessler, A; Stetter, K O; Prangishvili, D

    2002-12-01

    Electron microscopic studies of the viruses in two hot springs (85 degrees C, pH 1.5-2.0, and 75-93 degrees C, pH 6.5) in Yellowstone National Park revealed particles with twelve different morphotypes. This diversity encompassed known viruses of hyperthermophilic archaea, filamentous Lipothrixviridae, rod-shaped Rudiviridae, and spindle-shaped Fuselloviridae, and novel morphotypes previously not observed in nature. Two virus types resembled head-and-tail bacteriophages from the families Siphoviridae and Podoviridae, and constituted the first observation of these viruses in a hydrothermal environment. Viral hosts in the acidic spring were members of the hyperthermophilic archaeal genus Acidianus.

  18. Soft photons from off-shell particles in a hot plasma

    International Nuclear Information System (INIS)

    Henning, P.A.; Quack, E.

    1995-05-01

    Considering the propagation of off-shell particles in the framework of thermal field theory, we present the general formalism for the calculation of the production rate of soft photons and dileptons from a hot plasma. This approach is illustrated with an electrodynamic plasma. The photon production rate from strongly interacting quarks in the quark-gluon plasma, which might be formed in ultrarelativistic heavy ion collisions, is calculated in the previously unaccessible regime of photon energies of the order of the plasma temperature within an effective field theory incorporating dynamical chiral symmetry breaking. (orig.)

  19. The radiation factor 'hot particles': origin, methods of investigation, characterization and risk factors

    International Nuclear Information System (INIS)

    Bonchev, Ts.; Vapirev, E.; Yanev, Y.

    1993-01-01

    The problem of hot particles (HP) is reviewed chronologically following published data. The term appeared in the 50-s when HP have been found in fallout as a result of nuclear explosions in the atmosphere. After the Chernobyl accident there is a growing interest in HP. In 1986 HP have been discovered in American nuclear power plants (NPP) and in 1992 some have been found at Kozloduy NPP in Bulgaria as well. Detection and collection methods and different approaches for HP investigation are discussed. The direct and indirect risks from HP are described. It is concluded that the problem deserves further investigation and the discovery of HP inside NPP is of special interest

  20. The radiation factor `hot particles`: origin, methods of investigation, characterization and risk factors

    Energy Technology Data Exchange (ETDEWEB)

    Bonchev, Ts; Vapirev, E; Yanev, Y

    1994-12-31

    The problem of hot particles (HP) is reviewed chronologically following published data. The term appeared in the 50-s when HP have been found in fallout as a result of nuclear explosions in the atmosphere. After the Chernobyl accident there is a growing interest in HP. In 1986 HP have been discovered in American nuclear power plants (NPP) and in 1992 some have been found at Kozloduy NPP in Bulgaria as well. Detection and collection methods and different approaches for HP investigation are discussed. The direct and indirect risks from HP are described. It is concluded that the problem deserves further investigation and the discovery of HP inside NPP is of special interest.

  1. Hot gas path component cooling system having a particle collection chamber

    Science.gov (United States)

    Miranda, Carlos Miguel; Lacy, Benjamin Paul

    2018-02-20

    A cooling system for a hot gas path component includes a substrate having an outer surface and an inner surface. The inner surface defines at least one interior space. A passage is formed in the substrate between the outer surface and the inner surface. An access passage is formed in the substrate and extends from the outer surface to the inner space. The access passage is formed at a first acute angle to the passage and includes a particle collection chamber. The access passage is configured to channel a cooling fluid to the passage. Furthermore, the passage is configured to channel the cooling fluid therethrough to cool the substrate.

  2. Estimation of the solubility of radioactive aerosol particles in biological liquids

    International Nuclear Information System (INIS)

    Garger, E.K.; Odintsov, A.A.; Sazhenyuk, A.D.

    2003-01-01

    Solubility of aerosol 'hot' particles sampled in 1987 in the town of Pripyat in the simulated lung fluid (SLF) (Gamble or Ringer solution) and in 0.1 M HCl was studied under static conditions. Leaching of radionuclides from the 'hot' particles in SFL decreases in the order 137 Cs > 90 Sr >> 239+240 Pu > 241 Am, and in 0.1 M HCl in the order 90 Sr > 241 Am >> 137 Cs > 239+240 Pu. The degree of passing into 0.1 M HCl solution for 90 Sr and 241 Am was estimated at 3.3-21 and 2.7-17%, respectively. Depending on the particle size, 0.06-2.2% of 241 Am and 0.2-1.8% of 239+240 Pu passes into SLF within 28 days [ru

  3. Probing the degrees of freedom in hot composite nuclei. Systematics of charged particle evaporation

    International Nuclear Information System (INIS)

    Kaplan, M.; Downer, J.B.; Whitfield, J.P.; Brown, C.M.; Milosevich, Z.; Karol, P.J.; Vardaci, E.; Copi, C.; De Young, P.

    1995-01-01

    The study of evaporative particle emission offers a number of experimental observables whose measurement can provide insight into the behavior of highly excited composite nuclei. Simultaneous observations of multiple degrees of freedom in such hot systems allows stringent testing of theoretical models by insisting that the calculations reproduce the several measured characteristics with a single set of model input parameters. Such comparisons are presented for two data sets, one involving a relatively light (low Z) system and the other referring to a relatively heavy (high Z) system. In the latter case, reasonably good agreement has been found between statistical model calculations (with empirical barriers) and the experimental data, while for the former situation, the parameters required to reproduce the energy spectra lead to significant inconsistencies in predicted particle multiplicities and angular anisotropies. (authors). 12 refs., 7 figs., 2 tabs

  4. Dynamical aspects of particle emission in binary dissipative collisions -effects on hot-nuclei formation

    International Nuclear Information System (INIS)

    Eudes, Ph.; Basrak, Z.; Sebille, F.

    1997-01-01

    Characteristics of charged-particle emission in heavy-ion reactions have been studied in the framework of the semiclassical Landau-Vlasov approach for the 40 Ar + 27 Al collisions at 65 MeV/u. The reaction mechanism is dominated by binary dissipative collisions. After an abundant prompt emission coming from the overlapping region between the target and the projectile, two excited nuclei, the quasi-target and the quasi-projectile, emerge from the collision. To shed some light on the role played by dynamical effects, light-charged particle observables, which are currently used as an experimental signature a of hot equilibrated nucleus, have been carefully investigated. (K.A.)

  5. Radioactive Particle Tracking (RPT): The Powerful Industrial Radiotracer Techniques for Hydrodynamics and Flow Visualization Studies

    International Nuclear Information System (INIS)

    Mohd Amirul Syafiq Mohd Yunos

    2016-01-01

    Full text: Radioactive particle tracking (RPT) techniques have been widely applied in the field of chemical engineering, especially in hydrodynamics in multiphase reactors. This technique is widely used to monitor the motion of the flow inside a reactor by using a single radioactive particle tracer that is neutrally buoyant with respect to the phase is used as a tracker. The particle moves inside the volume of interest and its positions are determined by an array of scintillation detectors counting in coming photons. Particle position reconstruction algorithms have been traditionally used to map measured counts rate into the coordinates by solving a minimization problem between measured events and calibration data. RPT have been used to validate respective-scale CFD models to partial success. This presentation described an introduction to radioactive particle tracking and summarizing a history of such developments and the current state of this method in Malaysian Nuclear Agency, with a perspective towards the future and how these investigations may help scale-up developments. (author)

  6. A flowrate measurement method by counting of radioactive particles suspended in a liquid

    International Nuclear Information System (INIS)

    Daniel, G.

    1983-04-01

    By external counting of fine #betta# emitting radioactive particles suspended in a liquid, the flowrate in a system of pipes can be measured. The study comprises three phases: 1. - The hydraulic validity of the method is demonstrated in laminar as well as in turbulent flow under certain conditions of particles size and density and of liquid viscosity. 2. - Radioactive labelling of microspheres of serumalbumin or ion exchange resins with indium 113m delivered by a generator Tin 113 → Indium 113m. 3. - Counting with a scintillation detector: a method of threshold overstepping is experimented with a mechanical or electronic simulator; the statistical study of particle superposition under the detector enables a correction for the resulting counting losses to be proposed. The method provides absolute measurements, but is particularly suitable to measure relative flowrates in a hydraulic network. It can be continuous and does not perturb the flow and the network. The accuracy of the method is analysed in details [fr

  7. Hot-stage microscopy for determination of API particles in a formulated tablet.

    Science.gov (United States)

    Simek, Michal; Grünwaldová, Veronika; Kratochvíl, Bohumil

    2014-01-01

    Although methods exist to readily determine the particle size distribution (PSD) of an active pharmaceutical ingredient (API) before its formulation into a final product, the primary challenge is to develop a method to determine the PSD of APIs in a finished tablet. To address the limitations of existing PSD methods, we used hot-stage microscopy to observe tablet disintegration during temperature change and, thus, reveal the API particles in a tablet. Both mechanical and liquid disintegration were evaluated after we had identified optimum milling time for mechanical disintegration and optimum volume of water for liquid disintegration. In each case, hot-stage micrographs, taken before and after the API melting point, were compared with image analysis software to obtain the PSDs. Then, the PSDs of the APIs from the disintegrated tablets were compared with the PSDs of raw APIs. Good agreement was obtained, thereby confirming the robustness of our methodology. The availability of such a method equips pharmaceutical scientists with an in vitro assessment method that will more reliably determine the PSD of active substances in finished tablets.

  8. Hot-Stage Microscopy for Determination of API Particles in a Formulated Tablet

    Directory of Open Access Journals (Sweden)

    Michal Šimek

    2014-01-01

    Full Text Available Although methods exist to readily determine the particle size distribution (PSD of an active pharmaceutical ingredient (API before its formulation into a final product, the primary challenge is to develop a method to determine the PSD of APIs in a finished tablet. To address the limitations of existing PSD methods, we used hot-stage microscopy to observe tablet disintegration during temperature change and, thus, reveal the API particles in a tablet. Both mechanical and liquid disintegration were evaluated after we had identified optimum milling time for mechanical disintegration and optimum volume of water for liquid disintegration. In each case, hot-stage micrographs, taken before and after the API melting point, were compared with image analysis software to obtain the PSDs. Then, the PSDs of the APIs from the disintegrated tablets were compared with the PSDs of raw APIs. Good agreement was obtained, thereby confirming the robustness of our methodology. The availability of such a method equips pharmaceutical scientists with an in vitro assessment method that will more reliably determine the PSD of active substances in finished tablets.

  9. Dissociation of 1P states in hot QCD Medium Using Quasi-Particle Model

    Science.gov (United States)

    Nilima, Indrani; Agotiya, Vineet Kumar

    2018-03-01

    We extend the analysis of a very recent work [1] to study the dissociation phenomenon of 1P states of the charmonium and bottomonium spectra (χc and χb) in a hot QCD medium using Quasi-Particle Model. This study employed a medium modified heavy quark potential which has quite different form in the sense that it has a lomg range Coulombic tail in addition to the Yukawa term even above the deconfinement temperature. Then we study the flavor dependence of their binding energies and explore the nature of dissociation temperatures by employing the Quasi-Particle debye mass for pure gluonic and full QCD case. Interestingly, the dissociation temperatures obtained by employing EoS1 and EoS2 with the Γ criterion, is closer to the upper bound of the dissociation temperatures which are obtained by the dissolution of a given quarkonia state by the mean thermal energy of the quasi-partons in the hot QCD/QGP medium.

  10. Development and evaluation of an impactor sampler for radioactive aerosol particles

    International Nuclear Information System (INIS)

    Sorimachi, Atsuyuki; Kranrod, Chutima; Chantrarayotha, Supitcha; Tokonami, Shinji

    2008-01-01

    This sampler consists of one impaction stage, which allows separation of airborne particles by 1 μm particle size cut-off point with a 50% probability of impaction, followed by a back-up filter at a flow rate of 1 L min -1 . The particles size more than and less than 1 μm-diameter are collected on the impactor plate at the nozzle side and on the filter, respectively. A Cr-39 detector is mounted on the filter sides of the impaction plate; α particles emitted from the particles less than 1 μm-diameter are counted with the Cr-39 detectors. In order to separate α particles emitted from radon, thoron and their progeny, the Cr-39 detectors are covered with aluminum-vaporized Mylar films. The total thickness of films is adjusted to let their α particles impinge on the Cr-39 detectors. Laboratory tests are going on in terms of the spectral characteristics of α particles before and after passing through the films, the count rate performance of Cr-39 detectors by α particles, the actual collection efficiency of aerosol particles on the impaction plate, and so on. This sampler may be able to supply us with an interesting technique for measuring radon and thoron progeny come from the sources of natural radiation such as the naturally occurred radioactive materials. (author)

  11. Strategy for fitting source strength and reconstruction procedure in radioactive particle tracking

    International Nuclear Information System (INIS)

    Mosorov, Volodymyr

    2015-01-01

    The Radioactive Particle Tracking (RPT) technique is widely applied to study the dynamic properties of flows inside a reactor. Usually, a single radioactive particle that is neutrally buoyant with respect to the phase is used as a tracker. The particle moves inside a 3D volume of interest, and its positions are determined by an array of scintillation detectors, which count the incoming photons. The particle position coordinates are calculated by using a reconstruction procedure that solves a minimization problem between the measured counts and calibration data. Although previous studies have described the influence of specified factors on the RPT resolution and sensitivities, the question of how to choose an appropriate source strength and reconstruction procedure for the given RPT setup remains an unsolved problem. This work describes and applies the original strategy for fitting both the source strength and the sampling time interval to a specified RPT setup to guarantee a required accuracy of measurements. Additionally, the measurement accuracy of an RPT setup can be significantly increased by changing the reconstruction procedure. The results of the simulations, based on the Monte Carlo approach, have demonstrated that the proposed strategy allows for the successful implementation of the As Low As Reasonably Achievable (ALARA) principle when designing the RPT setup. The limitations and drawbacks of the proposed procedure are also presented. - Highlights: • We develop an original strategy for fitting source strength and measurement time interval in radioactive particle tracking (RPT) technique. • The proposed strategy allows successfully to implement the ALAPA (As Low As Reasonably Achievable) principle in designing of a RPT setup. • Measurement accuracy of a RPT setup can be significantly increased by improvement of the reconstruction procedure. • The algorithm can be applied to monitor the motion of the radioactive tracer in a reactor

  12. Studies at Dounreay on the repopulation of offshore sediments by hot particles

    International Nuclear Information System (INIS)

    Crawford, Ron; Toole, Joe; Innes, Steve

    2007-01-01

    Since 2000, much of the effort of diving surveys offshore of Dounreay to locate the presence of radioactive particles in the seabed sediments has been directed to a programme of repopulation studies, in which selected areas of the seabed have been surveyed a number of times and cleared of identified particles on each occasion. This work has led to an understanding of the distribution of particles within the seabed off Dounreay. The two-population model originally proposed by Atkinson (2001 UKAEA Document reference 000052) and further refined into three populations by Clayton and Atkinson (2002 UKAEA Document PSG Issue Note (02)33) has been substantially confirmed by the extended data set now available. It is apparent that the upper layers of the seabed sediments, containing a population of particles, are essentially mobile. These sediments migrate over the seabed driven by tidal wave and surge induced seabed currents, recontaminating areas which have been previously cleared of particles. The number of particles present in this layer at any given location has not been effectively reduced by the removal of particles over the years, nor has the distribution of activity within this population varied significantly. The highest concentration of particles, and the most active, reside close to and to the northeast of the effluent diffuser outfall. Particle numbers and their activity decrease with distance from the diffuser, and the rate of decrease is significantly greater to the southwest compared to the northeast. By contrast, there is evidence that the population of particles retained in the deeper sediments has changed significantly as a result of the repopulation surveys. Close to the diffuser, the population of particles identified at depth during initial surveys is high and contains significantly more highly active particles than are found in the surface sediments. It is also evident that once the deeper sediments are cleared of particles, the level of repopulation

  13. Induced fission track distribution from highly radioactive particles in fallout materials

    International Nuclear Information System (INIS)

    Hashimoto, Tetsuo; Okada, Tatemichi

    1987-01-01

    Some highly radioactive fallout particles (GPs) from the 19th Chinese nuclear detonation were followed to the neutron irradiation in a reactor after sandwiched with mica detectors. The interesting star-like fission track patterns were revealed on the etched surface of the mica detectors. The simple chemical separation procedure for the GPs was applied for the separation of U and Pu as fissile elements and the both resultant fractions were examined with the similar high sensitive fission tracking detection. Subsequently, a representative track pattern from a black spherical particle was subjected to the determination of fissile nuclide content; comparing the total fission events evaluated on the basis of the numerical calculation of track densities with the total thermal neutron fluence. The results implied that the uranium is responsible for the main fissile nuclide remaining within a particle as unfissioned fractions and should be certainly enriched with respect to U-235 within such small fallout particles. This sophisticated method was also applied to determine the dead GPs, which have been highly radioactive particles just after the detonations, in the rain and snow-residual materials. Many induced star-like fission tracks verified certainly that there remains a lot of dead particles in the atmosheric environment till nowadays. (author)

  14. Radioactive spent resins conditioning by the hot super-compaction process

    International Nuclear Information System (INIS)

    Roth, Andreas; Centner, Baudouin; Lemmens, Alain

    2007-01-01

    Spent ion exchanger media are considered to be problematic waste that, in many cases, requires special approaches and precautions during its immobilization to meet the acceptance criteria for disposal. The waste acceptance criteria define, among others, the quality of waste forms for disposal, and therefore will sometimes define appropriate treatment options. The selection of treatment options for spent ion exchange materials must consider their physical and chemical characteristics. Basically, the main methods for the treatment of spent organic ion exchange materials, following to pretreatment methods are: - Direct immobilization, producing a stable end product by using Cement, Bitumen, Polymer or High Integrity Containers, - The destruction of the organic compounds by using Thermochemical processes or Oxidation to produce an inorganic intermediate product that may or may not be further conditioned for storage and/or disposal, - The complete removal of the resin inner structural water by a thermal process. After a thorough technical economical analysis, Tractebel Engineering selected the Resin Hot Compaction Process to be installed at Tihange Nuclear Power Plant. The Resin Hot Compaction Process is used to make dense homogenous organic blocks from a wide range of particulate waste. In this process spent resins are first dewatered and dried to remove the inner structural water content. The drying takes place in a drying vessel that holds the contents of two 200 L drums (Figure). In the oil heated drying and mixing unit, the resins are heated to the necessary process temperature for the hot pressing step and then placed into special metal drums, which are automatically lidded and immediately transferred to a high force compactor. After high force compaction the pellets are transferred to a measuring unit, where the dose rate, height and weight are automatically measured and recorded. A volume reduction factor of approximately up to four (depending on the type of

  15. Impact of plasma-sprayed metal particles on hot and cold glass surfaces

    International Nuclear Information System (INIS)

    McDonald, A.; Lamontagne, M.; Moreau, C.; Chandra, S.

    2006-01-01

    Plasma-sprayed molten molybdenum and amorphous steel particles (38-55 μm diameter) were photographed during impact (velocity 120-200 m/s) and spreading on a smooth glass surface that was maintained at either room temperature or 400 deg. C. Droplets approaching the surface were identified by a photodetector and after a known delay, a 5-ns laser pulse was triggered to illuminate the spreading splat and photograph it with a charge-coupled device (CCD) camera. A rapid two-color pyrometer was used to collect thermal radiation from particles during flight and impact to follow the evolution of their temperature and size. Particles that impacted the surface at room temperature ruptured and splashed, leaving a small central solidified core on the substrate. On a surface held at 400 deg. C, there was no splashing and a circular, disk-like splat remained on the surface. Splats on a glass surface held at room temperature had a maximum spread diameter almost three times that on a hot surface. A simple analysis was done to estimate the area of the splat in contact with the non-heated glass surface during spreading. The analysis supports the hypothesis that only a portion of the splat is in good contact with the surface at room temperature, while the rest of the fluid is separated from the substrate by a gas barrier

  16. In-situ observations of Eyjafjallajökull ash particles by hot-air balloon

    Science.gov (United States)

    Petäjä, T.; Laakso, L.; Grönholm, T.; Launiainen, S.; Evele-Peltoniemi, I.; Virkkula, A.; Leskinen, A.; Backman, J.; Manninen, H. E.; Sipilä, M.; Haapanala, S.; Hämeri, K.; Vanhala, E.; Tuomi, T.; Paatero, J.; Aurela, M.; Hakola, H.; Makkonen, U.; Hellén, H.; Hillamo, R.; Vira, J.; Prank, M.; Sofiev, M.; Siitari-Kauppi, M.; Laaksonen, A.; lehtinen, K. E. J.; Kulmala, M.; Viisanen, Y.; Kerminen, V.-M.

    2012-03-01

    The volcanic ash cloud from Eyjafjallajökull volcanic eruption seriously distracted aviation in Europe. Due to the flight ban, there were only few in-situ measurements of the properties and dispersion of the ash cloud. In this study we show in-situ observations onboard a hot air balloon conducted in Central Finland together with regional dispersion modelling with SILAM-model during the eruption. The modeled and measured mass concentrations were in a qualitative agreement but the exact elevation of the layer was slightly distorted. Some of this discrepancy can be attributed to the uncertainty in the initial emission height and strength. The observed maximum mass concentration varied between 12 and 18 μg m -3 assuming a density of 2 g m -3, whereas the gravimetric analysis of the integrated column showed a maximum of 45 μg m -3 during the first two descents through the ash plume. Ion chromatography data indicated that a large fraction of the mass was insoluble to water, which is in qualitative agreement with single particle X-ray analysis. A majority of the super-micron particles contained Si, Al, Fe, K, Na, Ca, Ti, S, Zn and Cr, which are indicative for basalt-type rock material. The number concentration profiles indicated that there was secondary production of particles possibly from volcano-emitted sulfur dioxide oxidized to sulfuric acid during the transport.

  17. A review of airborne particle sampling with special reference to long-lived radioactive dust

    International Nuclear Information System (INIS)

    Bigu, J.

    1990-03-01

    This report reviews some basic aspects related to the sampling of airborne particles with special reference to Long-Lived Radioactive Dust (LLRD). The report covers a number of areas of practical interest such as the production of aerosols, the dynamics of suspended particles, the physical and chemical characteristics and properties of dust clouds, and the inhalation and measurement of dust. It is followed with a brief review of dust sampling instrumentation, and with a short account of the work done on LLRD in Canada with a few references to work done outside this country. (34 figs., 7 tabs., 117 refs.)

  18. Auto-radiographical study of activity distribution of high-dispersity hot particles from NPP

    International Nuclear Information System (INIS)

    Bonchev, Ts.; Andreev, Ts.; Todorov, N.; Andreev, P.; Kasabov, I.

    1995-01-01

    Autoradiograms of hot particles (HP) detected at Kozloduy NPP have been obtained with ordinary photographic film using direct contact. HP diameter and activity have been calculated by computer processing of the image.The distribution of HP weight and the precipitation time on surfaces has been estimated. Results on 37 HP found at the Kozloduy NPP units 1-4 and 9 HP found in special rooms containing waste are reported. The emitters are identified as 60 Co, 54 Mn and α emitters with specific activities 2.10 8 Bq/g, 2.10 7 Bq/g and 3.10 4 Bq/g respectively. 5 refs., 6 figs., 3 tabs

  19. Auto-radiographical study of activity distribution of high-dispersity hot particles from NPP

    Energy Technology Data Exchange (ETDEWEB)

    Bonchev, Ts [Sofia Univ. (Bulgaria). Fizicheski Fakultet; Angelov, V [Civil Defence Administration, Sofia (Bulgaria); Andreev, Ts; Todorov, N [Kombinat Atomna Energetika, Kozloduj (Bulgaria); Andreev, P; Kasabov, I [Sofia Univ. (Bulgaria). Fizicheski Fakultet

    1996-12-31

    Autoradiograms of hot particles (HP) detected at Kozloduy NPP have been obtained with ordinary photographic film using direct contact. HP diameter and activity have been calculated by computer processing of the image.The distribution of HP weight and the precipitation time on surfaces has been estimated. Results on 37 HP found at the Kozloduy NPP units 1-4 and 9 HP found in special rooms containing waste are reported. The emitters are identified as {sup 60} Co, {sup 54} Mn and {alpha} emitters with specific activities 2.10{sup 8} Bq/g, 2.10{sup 7} Bq/g and 3.10{sup 4} Bq/g respectively. 5 refs., 6 figs., 3 tabs.

  20. Techniques employed for detection of hot particles in the marine environment

    International Nuclear Information System (INIS)

    Pillsbury, G D

    2007-01-01

    During the decommissioning of the Maine Yankee nuclear plant, several methods were developed and employed to survey for hot particles in the marine environment surrounding the site. The methods used and the sensitivities achieved in the search for environmentally dispersed particles during the various decommissioning activities performed are described in detail. Surveys were performed on dry soil, exposed marine sediment and submerged marine sediment. Survey techniques ranged from the use of the basic NaI detector coupled to a count rate meter to an intrinsic germanium detector deployed in a submarine housing coupled to a multi-channel analyser. The initial surveys consisted of collecting samples of marine sediment, spreading them out over a 1 m 2 surface in a thin layer, and scanning the deposited sediment by hand using a 5 cm by 5 cm NaI detector coupled to a standard count rate meter. This technique was later replaced by walkover scans with the 5 cm by 5 cm NaI detector moved in a serpentine pattern over the sediment surface. By coupling the detector to a 'smart meter', an alarm set point could be used to alert the surveyor to the presence of a particle within the instrument's field of view. A similar technique, with the detector mounted in a watertight housing secured to the end of a pole, was also employed to scan underwater locations. The most sensitive method developed for performing underwater surveys was the use of the intrinsic germanium detector placed in a submarine housing. Detailed descriptions of the methods employed and the results obtained are presented. This work demonstrates that there are several approaches to surveying for discrete particles in the marine environment and the relative merits of each are considered

  1. Desorption of radioactive cesium by seawater from the suspended particles in river water.

    Science.gov (United States)

    Onodera, Masaki; Kirishima, Akira; Nagao, Seiya; Takamiya, Kouichi; Ohtsuki, Tsutomu; Akiyama, Daisuke; Sato, Nobuaki

    2017-10-01

    In 2011, the accident at the Fukushima-Daiichi nuclear power plant dispersed radioactive cesium throughout the environment, contaminating the land, rivers, and sea. Suspended particles containing clay minerals are the transportation medium for radioactive cesium from rivers to the ocean because cesium is strongly adsorbed between the layers of clay minerals, forming inner sphere complexes. In this study, the adsorption and desorption behaviors of radioactive cesium from suspended clay particles in river water have been investigated. The radioactive cesium adsorption and desorption experiments were performed with two kinds of suspended particulate using a batch method with 137 Cs tracers. In the cesium adsorption treatment performed before the desorption experiments, simulated river water having a total cesium concentration ([ 133+137 Cs + ] total ) of 1.3 nM (10 -9  mol/L) was used. The desorption experiments were mainly conducted at a solid-to-liquid ratio of 0.17 g/L. The desorption agents were natural seawater collected at 10 km north of the Fukushima-Daiichi nuclear power plant, artificial seawater, solutions of NaCl, KCl, NH 4 Cl, and 133 CsCl, and ultrapure water. The desorption behavior, which depends on the preloaded cesium concentration in the suspended particles, was also investigated. Based on the cesium desorption experiments using suspended particles, which contained about 1000 ng/g loaded cesium, the order of cesium desorption ratios for each desorption agent was determined as 1 M NaCl (80%) > 470 mM NaCl (65%) > 1 M KCl (30%) ≈ seawater (natural seawater and Daigo artificial seawater) > 1 M NH 4 Cl (20%) > 1 M 133 CsCl (15%) ≫ ultrapure water (2%). Moreover, an interesting result was obtained: The desorption ratio in the 470 mM NaCl solution was much higher than that in seawater, even though the Na + concentrations were identical. These results indicate that the cesium desorption mechanism is not a simple ion exchange reaction

  2. Size distribution of natural aerosols and radioactive particles issued from radon, in marine and hardly polluted urban atmospheres

    International Nuclear Information System (INIS)

    Tymen, Georges.

    1979-03-01

    With a view to studying the natural radioactive particles produced by atttachment of 222 Rn daughters on environmental aerosol particles, the behaviours of CASELLA MK2 and ANDERSEN cascade impactors were first investigated. Their characteristic stage diameters were determined and size distributions of airborne particles were obtained in various situations. Moreover, an experimental and automatic equipment for measuring radon was devised and a method was developed in order to evaluate RaA, RaB, RaC concentrations in the free atmosphere. A degree of radioactive desequilibrium between 222 Rn and its daughters, more important than that in other locations was thus demonstrated. Furthermore, by means of various aerosol collection systems (ion tubes, diffusion batteries, cascade impactors, filters), the cumulative size distribution of natural radioactivity was established in the air, at ground level. Finally, from a theory of attachment of small radioactive ions on atmospheric particles, a tentative explanation of experimental results was made [fr

  3. A review of methods for sampling large airborne particles and associated radioactivity

    International Nuclear Information System (INIS)

    Garland, J.A.; Nicholson, K.W.

    1990-01-01

    Radioactive particles, tens of μm or more in diameter, are unlikely to be emitted directly from nuclear facilities with exhaust gas cleansing systems, but may arise in the case of an accident or where resuspension from contaminated surfaces is significant. Such particles may dominate deposition and, according to some workers, may contribute to inhalation doses. Quantitative sampling of large airborne particles is difficult because of their inertia and large sedimentation velocities. The literature describes conditions for unbiased sampling and the magnitude of sampling errors for idealised sampling inlets in steady winds. However, few air samplers for outdoor use have been assessed for adequacy of sampling. Many size selective sampling methods are found in the literature but few are suitable at the low concentrations that are often encountered in the environment. A number of approaches for unbiased sampling of large particles have been found in the literature. Some are identified as meriting further study, for application in the measurement of airborne radioactivity. (author)

  4. Risk assessment of hot beta-particles from the Chernobyl fallout in Bulgaria

    International Nuclear Information System (INIS)

    Uzunov, I.

    1993-01-01

    Research on hot particles (HP) was carried out in the Laboratory of Dosimetry and Radiation Protection. Field measurements with a Geiger-counter led to early discovery of HP on the ground in May 1986. Laboratory measurements of HP activity followed and their nuclide composition was determined. The carcinogenic risk of HP is discussed on the basis of a computer model assuming the radiation as initiator and all other factors as stimulators for cell proliferation (promoters). It is found that in the case of low radiation dose the probability for cancer is almost directly proportional to the number of cell divisions while at high radiation dose the slope is nearly vertical and reaches saturation point at about 5 cell divisions. An estimation of the number of inhaled HP was made by investigation of air filters. It is concluded that, besides iodine, inhaled HP are the most hazardous factor of the Chernobyl fallout. For some critical groups of the population, engaged in dusty outdoor operations, the carcinogenic risk was estimates as high as 0.1 - 1%. An average activity of 50 Bq per retained particle is proposed. It is stressed that Bulgarian population had not been informed adequately and no protection measures against HP intake had been taken. 3 figs., 12 refs

  5. Risk assessment of hot beta-particles from the Chernobyl fallout in Bulgaria

    Energy Technology Data Exchange (ETDEWEB)

    Uzunov, I

    1994-12-31

    Research on hot particles (HP) was carried out in the Laboratory of Dosimetry and Radiation Protection. Field measurements with a Geiger-counter led to early discovery of HP on the ground in May 1986. Laboratory measurements of HP activity followed and their nuclide composition was determined. The carcinogenic risk of HP is discussed on the basis of a computer model assuming the radiation as initiator and all other factors as stimulators for cell proliferation (promoters). It is found that in the case of low radiation dose the probability for cancer is almost directly proportional to the number of cell divisions while at high radiation dose the slope is nearly vertical and reaches saturation point at about 5 cell divisions. An estimation of the number of inhaled HP was made by investigation of air filters. It is concluded that, besides iodine, inhaled HP are the most hazardous factor of the Chernobyl fallout. For some critical groups of the population, engaged in dusty outdoor operations, the carcinogenic risk was estimates as high as 0.1 - 1%. An average activity of 50 Bq per retained particle is proposed. It is stressed that Bulgarian population had not been informed adequately and no protection measures against HP intake had been taken. 3 figs., 12 refs.

  6. Assessing the environmental risk from hot particles in the vicinity of Dounreay-a case for inaction?

    International Nuclear Information System (INIS)

    Jackson, D; Stone, D M; Smith, K; Morgan, G; Shimmield, T

    2007-01-01

    This study assesses the impact on species other than humans associated with radioactive particles present in the marine environment close to the UKAEA Dounreay site, through a review of marine survey data, to establish the distribution of species and the likelihood of encountering a particle, and considering retention, dissolution or absorption of the particle. Assumptions are made regarding particle density, distribution, size and bio-availability of the radioactive materials. From this, impacts are assessed against the likelihood of mortality or other significant harm to individuals and interpreted in terms of local populations. Results obtained indicate that no significant impact, at the population level, is likely to be observed. This does not preclude that some individuals will be affected. It does, however, suggest that any decision to remediate, if based predominantly on environmental considerations, should be cognisant of the damage caused by remediation itself and subsequent exploitation of the environment by humans

  7. Particle-in-cell studies of laser-driven hot spots and a statistical model for mesoscopic properties of Raman backscatter

    International Nuclear Information System (INIS)

    Albright, B.J.; Yin, L.; Bowers, K.J.; Kline, J.L.; Montgomery, D.S.; Fernandez, J.C.; Daughton, W.

    2006-01-01

    The authors use explicit particle-in-cell simulations to model stimulated scattering processes in media with both solitary and multiple laser hot spots. These simulations indicate coupling among hot spots, whereby scattered light, plasma waves, and hot electrons generated in one laser hot spot may propagate to neighboring hot spots, which can be destabilized to enhanced backscatter. A nonlinear statistical model of a stochastic beam exhibiting this coupled behavior is described here. Calibration of the model using particle-in-cell simulations is performed, and a threshold is derived for 'detonation' of the beam to high reflectivity. (authors)

  8. Testing and assessment of a large BGO detector for beach monitoring of radioactive particles

    International Nuclear Information System (INIS)

    Graaf, E.R. van der; Rigollet, C.; Maleka, P.P.; Jones, D.G.

    2007-01-01

    The Beach Monitoring Steering Group (BMSG) was set up by UKAEA to explore whether improved systems for beach monitoring of radioactive particles are available. The BMSG commissioned the British Geological Survey (BGS) and the Nuclear Geophysics Division of the Kernfysisch Versneller Instituut (KVI/NGD), and other companies, to test their most sensitive system. This paper presents the results of trials in a specially created test facility at UKAEA Harwell with a large BGO detector. The detector's size and weight mean that it would be suitable for vehicle deployment but would be too large and heavy to carry in areas that could not be accessed by a vehicle. However, it would be possible to use the same methodology that is described here with a smaller detector capable of being carried in a backpack, albeit with reduced sensitivity for particle detection. The approach that we present is also applicable, with modifications, to the detection of offshore particles using a towed seabed detector

  9. Production of microspheres for the computer automated radioactive particle tracking technique (CARPT)

    International Nuclear Information System (INIS)

    Vieira, Wilson S.; Pinto, Jose Carlos C.S.; Nele, Marcio

    2013-01-01

    The CARPT technique is a non-destructive test that uses a radiotracer in the form of a single particle to determine patterns of fluid displacement or to develop numerical models for multiphase dynamic systems. Through it, velocity profiles of fluids or even concentration profiles of a phase can be visualized and the diagnose of phenomena in industrial processes related to fluid dynamics can be performed (e.g. recirculations, eddies, segregation zones or diffusivities ). In this work, spherical shaped particles composed of polymethyl methacrylate (PMMA) and lanthanum oxide, about 0,2 mm in diameter, were obtained. They showed a satisfactory behavior in water after they had been dried for 24 h. In this manner, the synthesized spheres with a mean density of 1003,2 ± 0,1 kg/m 3 , containing a lanthanum oxide fractional mass of about 5 %, are prompt to be tested as a new type of radioactive tracer particle. (author)

  10. Method of determining the characteristics of circulatory systems using tracer particles, making the particles and radioactive particles for use in the method

    International Nuclear Information System (INIS)

    Pratt, F.P.; Gagnon, D.L.

    1981-01-01

    In the method described tracer particles consist of ion exchange resin cores labelled with suitable radioactive ions or with a nuclide excitable by X-rays, and have a non-leaching polymeric coating. The particles are introduced into the system and are detected by visual inspection, radiation detection or X-ray fluorescence techniques. The cores are labelled using conventional batch ion exchange techniques. Coated tracers are produced by contacting a monomer, preferably furfuryl alcohol, with cores bearing catalytic ions (hydroxyl or hydrogen) on the surface which catalyse the monomer to form a polymer. The tracer particles in a physiologically acceptable liquid carrier are useful in clinical and medical investigations of blood flow. They can also be used for flow measurement in chemical process control streams. (U.K.)

  11. Radioactive Pollution Estimate for Fukushima Nuclear Power Plant by a Particle Model

    Science.gov (United States)

    Saito, Keisuke; Ogawa, Susumu

    2016-06-01

    On Mar 12, 2011, very wide radioactive pollution occurred by a hydrogen explosion in Fukushima Nuclear Power Plant. A large amount of radioisotopes started with four times of explosions. With traditional atmospheric diffusion models could not reconstruct radioactive pollution in Fukushima. Then, with a particle model, this accident was reconstructed from meteorological archive and Radar- AMeDAS. Calculations with the particle model were carried out for Mar 12, 15, 18 and 20 when east southeast winds blew for five hours continuously. Meteorological archive is expressed by wind speeds and directions in five-km grid every hour with eight classes of height till 3000 m. Radar- AMeDAS is precipitation data in one-km grid every thirty minutes. Particles are ten scales of 0.01 to 0.1 mm in diameter with specific weight of 2.65 and vertical speeds given by Stokes equation. But, on Mar 15, it rained from 16:30 and then the particles fell down at a moment as wet deposit in calculation. On the other hand, the altitudes on the ground were given by DEM with 1 km-grid. The spatial dose by emitted radioisotopes was referred to the observation data at monitoring posts of Tokyo Electric Power Company. The falling points of radioisotopes were expressed on the map using the particle model. As a result, the same distributions were obtained as the surface spatial dose of radioisotopes in aero-monitoring by Ministry of Education, Culture, Sports, Science and Technology. Especially, on Mar 15, the simulated pollution fitted to the observation, which extended to the northwest of Fukushima Daiichi Nuclear Power Plant and caused mainly sever pollution. By the particle model, the falling positions on the ground were estimated each particle size. Particles with more than 0.05 mm of size were affected by the topography and blocked by the mountains with the altitudes of more than 700 m. The particle model does not include the atmospheric stability, the source height, and deposit speeds. The

  12. Mobile hot cell transition design phase study for radioactive waste treatment on the Hanford reservation site

    International Nuclear Information System (INIS)

    Pons, Y.

    2010-01-01

    Full text of publication follows: At the US Department of Energy's Hanford Reservation site, 4 caissons in under ground storage contain approximately 23 cubic meters of Transuranic (TRU) waste, in over 5,000 small packages. The retrieval of these wastes presents a number of very difficult issues, including the configuration of the vaults, approximately 50,000 curies of activity, high dose rates, and damaged/degraded waste packages. The waste will require remote retrieval and processing sufficient to produce certifiable RH-TRU waste packages. This RH-TRU will be packaged for staging on site until certification by CCP is completed to authorize shipment to the Waste Isolation Pilot Plant (WIPP). The project has introduced AREVA' s innovative Hot Mobile Cell (HMC) technology to perform size reduction, sorting, characterization, and packaging of the RH waste stream at the point of generation, the retrieval site in the field. This approach minimizes dose and hazard exposure to workers that is usually associated with this operation. The HMC can also be used to provide employee protection, weather protection, and capacity improvements similar to those realized in general burial ground. AREVA TA and his partner AFS will provide this technology based on the existing HMCs developed and operated in France: - ERFB (Bituminized Waste Drum Retrieval Facility): ERFB was built specifically for retrieving the bituminized waste drums (approximately 6,000 stored in trenches in the North zone on the Marcoule site (in operation since 2001). - ERCF (Waste Drum Recovery and Packaging Facility): The ERCF was built specifically to retrieve bituminized waste drums stored in 35 pits located in the south area on Marcoule site (in operation) - FOSSEA (Legacy Waste Removal and Trench Cleanup): The FOSSEA project consists of the retrieval of waste stored on the Basic Nuclear Facility. Waste from the 56 trenches will be inspected, characterised, and if necessary processed or repackaged, and

  13. Radioactivity

    International Nuclear Information System (INIS)

    Chelet, Y.

    2006-01-01

    The beginning of this book explains the why and how of the radioactivity, with a presentation of the different modes of disintegration. Are tackled the reports between radioactivity and time before explaining how the mass-energy equivalence appears during disintegrations. Two chapters treat natural radioisotopes and artificial ones. This book makes an important part to the use of radioisotopes in medicine (scintigraphy, radiotherapy), in archaeology and earth sciences (dating) before giving an inventory of radioactive products that form in the nuclear power plants. (N.C.)

  14. Radioactivity

    International Nuclear Information System (INIS)

    2002-01-01

    This pedagogical document presents the origin, effects and uses of radioactivity: where does radioactivity comes from, effects on the body, measurement, protection against radiations, uses in the medical field, in the electric power industry, in the food (ionization, radio-mutagenesis, irradiations) and other industries (radiography, gauges, detectors, irradiations, tracers), and in research activities (dating, preservation of cultural objects). The document ends with some examples of irradiation levels (examples of natural radioactivity, distribution of the various sources of exposure in France). (J.S.)

  15. Development of an ICCD-scintillator system for measurement of spatial dose distributions around 'hot particles'

    International Nuclear Information System (INIS)

    Aydarous, A. Sh; Darley, P. J.; Charles, M. W.

    2004-01-01

    An intensified charge coupled device (ICCD)-scintillator system has been investigated for potential use in measuring the spatially non-uniform dose distribution around 'hot particles'. This imaging system is capable of producing real-time measurements considerably quicker than other presently available radiation dosimetry techniques and exhibits good linearity and reproducibility and relatively high spatial resolution (∼17.5 μm). The time required for a dose evaluation is less than a hundredth that required for radiochromic dye film measurements. The non-uniformity of the system has been eliminated by applying pixel-to-pixel correction factors. The measurable dose rate range using a 110 μm thick scintillator extends from ∼2000 down to ∼6 Gy h -1 . The prototype ICCD-scintillator system has been used in evaluation of the skin dose from some high-activity nuclear fuel fragments. The results agree within a few percentage with radiochromic dye film measurements for 1 cm 2 averaging areas. (authors)

  16. GAMCAT - a personal computer database on alpha particles and gamma rays from radioactive decay

    International Nuclear Information System (INIS)

    Tepel, J.W.; Mueller, H.W.

    1990-01-01

    The GAMCAT database is a compilation of data describing the alpha particles and gamma rays that occur in the radioactive decay of all known nuclides, adapted for IBM Personal Computers and compatible systems. These compiled data have been previously published, and are now available as a compact database. Entries can be retrieved by defining the properties of the parent nuclei as well as alpha-particle and gamma-ray energies or any combination of these parameters. The system provides fast access to the data and has been completely written in C to run on an AT-compatible computer, with a hard disk and 640K of memory under DOS 2.11 or higher. GAMCAT is available from the Fachinformationszentrum Karlsruhe. (orig.)

  17. DCHAIN-SP 2001: High energy particle induced radioactivity calculation code

    Energy Technology Data Exchange (ETDEWEB)

    Kai, Tetsuya; Maekawa, Fujio; Kasugai, Yoshimi; Takada, Hiroshi; Ikeda, Yujiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kosako, Kazuaki [Sumitomo Atomic Energy Industries, Ltd., Tokyo (Japan)

    2001-03-01

    For the purpose of contribution to safety design calculations for induced radioactivities in the JAERI/KEK high-intensity proton accelerator project facilities, the DCHAIN-SP which calculates the high energy particle induced radioactivity has been updated to DCHAIN-SP 2001. The following three items were improved: (1) Fission yield data are included to apply the code to experimental facility design for nuclear transmutation of long-lived radioactive waste where fissionable materials are treated. (2) Activation cross section data below 20 MeV are revised. In particular, attentions are paid to cross section data of materials which have close relation to the facilities, i.e., mercury, lead and bismuth, and to tritium production cross sections which are important in terms of safety of the facilities. (3) User-interface for input/output data is sophisticated to perform calculations more efficiently than that in the previous version. Information needed for use of the code is attached in Appendices; the DCHAIN-SP 2001 manual, the procedures of installation and execution of DCHAIN-SP, and sample problems. (author)

  18. Lognormal Distribution of Cellular Uptake of Radioactivity: Statistical Analysis of α-Particle Track Autoradiography

    Science.gov (United States)

    Neti, Prasad V.S.V.; Howell, Roger W.

    2010-01-01

    Recently, the distribution of radioactivity among a population of cells labeled with 210Po was shown to be well described by a log-normal (LN) distribution function (J Nucl Med. 2006;47:1049–1058) with the aid of autoradiography. To ascertain the influence of Poisson statistics on the interpretation of the autoradiographic data, the present work reports on a detailed statistical analysis of these earlier data. Methods The measured distributions of α-particle tracks per cell were subjected to statistical tests with Poisson, LN, and Poisson-lognormal (P-LN) models. Results The LN distribution function best describes the distribution of radioactivity among cell populations exposed to 0.52 and 3.8 kBq/mL of 210Po-citrate. When cells were exposed to 67 kBq/mL, the P-LN distribution function gave a better fit; however, the underlying activity distribution remained log-normal. Conclusion The present analysis generally provides further support for the use of LN distributions to describe the cellular uptake of radioactivity. Care should be exercised when analyzing autoradiographic data on activity distributions to ensure that Poisson processes do not distort the underlying LN distribution. PMID:18483086

  19. Study of particle size distribution and formation mechanism of radioactive aerosols generated in high-energy neutron fields

    CERN Document Server

    Endo, A; Noguchi, H; Tanaka, S; Iida, T; Furuichi, S; Kanda, Y; Oki, Y

    2003-01-01

    The size distributions of sup 3 sup 8 Cl, sup 3 sup 9 Cl, sup 8 sup 2 Br and sup 8 sup 4 Br aerosols generated by irradiations of argon and krypton gases containing di-octyl phthalate (DOP) aerosols with 45 MeV and 65 MeV quasi-monoenergetic neutrons were measured in order to study the formation mechanism of radioactive particles in high energy radiation fields. The effects of the size distribution of the radioactive aerosols on the size of the added DOP aerosols, the energy of the neutrons and the kinds of nuclides were studied. The observed size distributions of the radioactive particles were explained by attachment of the radioactive atoms generated by the neutron-induced reactions to the DOP aerosols. (author)

  20. Determination of uranium isotopic composition and 236U content of soil samples and hot particles using inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Boulyga, S F; Becker, J S

    2001-07-01

    As a result of the accident at the Chernobyl nuclear power plant (NPP) the environment was contaminated with spent nuclear fuel. The 236U isotope was used in this study to monitor the spent uranium from nuclear fallout in soil samples collected in the vicinity of the Chernobyl NPP. Nuclear track radiography was applied for the identification and extraction of hot radioactive particles from soil samples. A rapid and sensitive analytical procedure was developed for uranium isotopic ratio measurement in environmental samples based on double-focusing inductively coupled plasma mass spectrometry (DF-ICP-MS) with a MicroMist nebulizer and a direct injection high-efficiency nebulizer (DIHEN). The performance of the DF-ICP-MS with a quartz DIHEN and plasma shielded torch was studied. Overall detection efficiencies of 4 x 10(-4) and 10(-3) counts per atom were achieved for 238U in DF-ICP-QMS with the MicroMist nebulizer and DIHEN, respectively. The rate of formation of uranium hydride ions UH+/U+ was 1.2 x 10(-4) and 1.4 x 10(-4), respectively. The precision of short-term measurements of uranium isotopic ratios (n = 5) in 1 microg L(-1) NBS U-020 standard solution was 0.11% (238U/235U) and 1.4% (236U/238U) using a MicroMist nebulizer and 0.25% (235U/238U) and 1.9% (236U/P38U) using a DIHEN. The isotopic composition of all investigated Chernobyl soil samples differed from those of natural uranium; i.e. in these samples the 236U/238U ratio ranged from 10(-5) to 10(-3). Results obtained with ICP-MS, alpha- and gamma-spectrometry showed differences in the migration properties of spent uranium, plutonium, and americium. The isotopic ratio of uranium was also measured in hot particles extracted from soil samples.

  1. Determination of uranium isotopic composition and 236U content of soil samples and hot particles using inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Boulyga, S.F.; Becker, J.S.

    2001-01-01

    As a result of the accident at the Chernobyl nuclear power plant (NPP) the environment was contaminated with spent nuclear fuel. The 236 U isotope was used in this study to monitor the spent uranium from nuclear fallout in soil samples collected in the vicinity of the Chernobyl NPP. Nuclear track radiography was applied for the identification and extraction of hot radioactive particles from soil samples. A rapid and sensitive analytical procedure was developed for uranium isotopic ratio measurement in environmental samples based on double-focusing inductively coupled plasma mass spectrometry (DF-ICP-MS) with a MicroMist nebulizer and a direct injection high-efficiency nebulizer (DIHEN). The performance of the DF-ICP-MS with a quartz DIHEN and plasma shielded torch was studied. Overall detection efficiencies of 4 x 10 -4 and 10 -3 counts per atom were achieved for 238 U in DF-ICP-QMS with the MicroMist nebulizer and DIHEN, respectively. The rate of formation of uranium hydride ions UH + /U + was 1.2 x 10 -4 and 1.4 x 10 -4 , respectively. The precision of short-term measurements of uranium isotopic ratios (n = 5) in 1 μg L -1 NBS U-020 standard solution was 0.11% ( 238 U/ 235 U) and 1.4% ( 236 U/ 238 U) using a MicroMist nebulizer and 0.25% ( 235 U/ 238 U) and 1.9% ( 236 U/ 238 U) using a DIHEN. The isotopic composition of all investigated Chernobyl soil samples differed from those of natural uranium; i.e. in these samples the 236 U/ 238 U ratio ranged from 10 -5 to 10 -3 . Results obtained with ICP-MS, α- and γ-spectrometry showed differences in the migration properties of spent uranium, plutonium, and americium. The isotopic ratio of uranium was also measured in hot particles extracted from soil samples. (orig.)

  2. An application of Brookhaven National Laboratory's hot particle methodology for determining the most effective beta particle energy in causing skin ulcers

    International Nuclear Information System (INIS)

    Schaefer, C.

    1994-11-01

    The purpose of this project was to compare the effectiveness of hot particles with different energy betas in producing ulcers on skin. The sources were man-made hot particles similar in size and activity to those found in the commercial nuclear power industry. Four different particle types were used. These were thulium (Tm-170) with a 0.97 MeV maximum energy beta, ytterbium (Yb-175) with a maximum beta energy of 0.47 MeV, scandium (Sc-46) with a 0.36 MeV beta, which was used as a surrogate for cobalt-60 (0.31 MeV beta) and uranium (in the carbide form) with an average maximum beta energy of about 2.5 MeV. Since higher energy beta particles penetrate further in skin, they will affect a higher number and different populations of target cells. The experiments were designed as threshold studies such that the dose needed to produce ulcers ten percent of the time (ED 10%) for each particle type could be compared against each other

  3. Observation of radioactive aerosol particle sizes in 30-km zone of the ChNPP in 1986-1987 years

    International Nuclear Information System (INIS)

    Skitovich, V.I.; Budyka, A.K.; Ogorodnikov, B.I.

    1989-01-01

    Investigation into disperse composition of radioactive aerosols was conducted in the ChNPP spaces, over ruins of 4 block, on job site and separate points of the 30-km zone by multilayer filters from ultrathin fibers. In probes taken from the job site radioactive isotopes were grouped on the particles with more than 2,5 μcm diameter. Particle sizes in the room were less than near terrestrial layer of atmosphere on job site. It is shown that the aerosol sizes containing alpha active nuclides are idential with gamma radiating isotopes of refractory elements. 4 refs., 1 fig., 2 tabs

  4. Lung Deposition Calculations for Radioactive Aerosol Particles Originating from Caves and Uranium Mines

    International Nuclear Information System (INIS)

    Alfoldy, B.; Torok, Sz.; Winkler, R.

    2001-01-01

    Full text: The present study simulates lung deposition of radioactive aerosol particles originating from the atmosphere of a therapeutic cave (Szemlohegyi cave, Budapest) and several uranium mines. Particle deposition patterns and surface densities have been calculated by the stochastic lung model of Koblinger and Hofmann. In the model, deposition can be caused by the simultaneous effects of Brownian motion, inertial impaction and gravitational settling. The calculations were carried out by considering the aerosol particle size distribution and radon concentration of the atmosphere of the cave and mines. The deposition was computed in the whole lung, in characteristic parts of the respiratory system such as extrathoracic, tracheobronchial, acinar and alveolar regions and in the singe airway generations at different flow rates for adults. The adverse health effects of inhaled radionuclides strongly depend from the local deposition density values in cellular dimensions. Thus we will built in the results to a cellular effects model of Balashazy and Hofmann for the simulation of the pathological effects of inhaled radionuclides for risk assessment. (author)

  5. Radioactive waste management, decommissioning, spent fuel storage. V. 1. Waste management principles, decommissioning, dismantling, operations in hot environment

    International Nuclear Information System (INIS)

    1985-01-01

    This book deals mainly with decommissioning problems concerning more particularly dismantling and decontamination techniques, and radioactive waste processing. Radioactive waste management in France and the French regulation are tackled. Equipments developed for works in hostile environment are also presented [fr

  6. Development of Labview based data acquisition and multichannel analyzer software for radioactive particle tracking system

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Nur Aira Abd, E-mail: nur-aira@nuclearmalaysia.gov.my; Yussup, Nolida; Ibrahim, Maslina Bt. Mohd; Abdullah, Nor Arymaswati; Mokhtar, Mukhlis B. [Technical Support Division, Malaysian Nuclear Agency, 43000, Kajang, Selangor (Malaysia); Abdullah, Jaafar B.; Hassan, Hearie B. [Industrial Technology Division, Malaysian Nuclear Agency, 43000, Kajang, Selangor (Malaysia)

    2015-04-29

    A DAQ (data acquisition) software called RPTv2.0 has been developed for Radioactive Particle Tracking System in Malaysian Nuclear Agency. RPTv2.0 that features scanning control GUI, data acquisition from 12-channel counter via RS-232 interface, and multichannel analyzer (MCA). This software is fully developed on National Instruments Labview 8.6 platform. Ludlum Model 4612 Counter is used to count the signals from the scintillation detectors while a host computer is used to send control parameters, acquire and display data, and compute results. Each detector channel consists of independent high voltage control, threshold or sensitivity value and window settings. The counter is configured with a host board and twelve slave boards. The host board collects the counts from each slave board and communicates with the computer via RS-232 data interface.

  7. Impurity 'hot' atoms 67Ga in a role a physical-chemical studies at an estimation of radiation damage in Zn cyclotron targets after bombardment with charged particles

    International Nuclear Information System (INIS)

    Alekseev, I.E.; Lazarev, V.V.

    2006-01-01

    In this paper, the migration of impurity 'hot atoms' 67 Ga produced from various types of nuclear reaction on zinc targets is reported. The type of charged particles as well as their energy, beam current, total fluency was varied

  8. Radioactive aerosols

    International Nuclear Information System (INIS)

    Chamberlain, A.C.

    1991-01-01

    Radon. Fission product aerosols. Radioiodine. Tritium. Plutonium. Mass transfer of radioactive vapours and aerosols. Studies with radioactive particles and human subjects. Index. This paper explores the environmental and health aspects of radioactive aerosols. Covers radioactive nuclides of potential concern to public health and applications to the study of boundary layer transport. Contains bibliographic references. Suitable for environmental chemistry collections in academic and research libraries

  9. Microstructural study and densification analysis of hot work tool steel matrix composites reinforced with TiB{sub 2} particles

    Energy Technology Data Exchange (ETDEWEB)

    Fedrizzi, A., E-mail: anna.fedrizzi@ing.unitn.it [Department of Industrial Engineering, University of Trento, Via Mesiano 77, 38123 Trento (Italy); Pellizzari, M. [Department of Industrial Engineering, University of Trento, Via Mesiano 77, 38123 Trento (Italy); Zadra, M. [K4Sint, Start-up of the University of Trento, Viale Dante 300, 38057 Pergine Valsugana (Italy); Marin, E. [Department of Chemistry, Physics and Environment, University of Udine, Via Cotonificio 108, 33100 Udine (Italy)

    2013-12-15

    Hot work tool steels are characterized by good toughness and high hot hardness but are less wear resistant than other tooling materials, such as high speed steel. Metal matrix composites show improved tribological behavior, but not much work has been done in the field of hot work tool steels. In this paper TiB{sub 2}-reinforced hot work tool steel matrix composites were produced by spark plasma sintering (SPS). Mechanical alloying (MA) was proposed as a suited process to improve the composite microstructure. Density measurements and microstructure confirmed that MA promotes sintering and produces a fine and homogeneous dispersion of reinforcing particles. X-ray diffraction patterns of the sintered composites highlighted the formation of equilibrium Fe{sub 2}B and TiC, as predicted by thermodynamic calculations using Thermo-Calc® software. Scanning electron microscopy as well as scanning Kelvin probe force microscopy highlighted the reaction of the steel matrix with TiB{sub 2} particles, showing the formation of a reaction layer at the TiB{sub 2}-steel interface. Phase investigations pointed out that TiB{sub 2} is not chemically stable in steel matrix because of the presence of carbon even during short time SPS. - Highlights: • TiB{sub 2} reinforced steel matrix composites were produced by spark plasma sintering. • TiB{sub 2} was successfully dispersed in the steel matrix by mechanical alloying. • Steel and TiB{sub 2} react during sintering forming equilibrium Fe{sub 2}B and TiC. • The new phases were investigated by means of AFM, Volta potential and XRD analyses.

  10. Influence of hard particle addition and chemical interdiffusion on the properties of hot extruded tool steel compounds

    International Nuclear Information System (INIS)

    Silva, P.A.; Weber, S.; Inden, G.; Pyzalla, A.R.

    2009-01-01

    Low alloyed steel bars were co-extruded with pre-sintered tool steel powders with the addition of tungsten carbides (W 2 C/WC) as hard particles. During the hot extrusion process of these massive and powdery materials, an extrudate is formed consisting of a completely densified wear resistant coating layer and a bulk steel bar as the tough substrate core. This work combines experimental measurements (EPMA) and diffusion calculations (DICTRA TM ) to investigate the effect of hard particle addition and its dissolution, as well as the formation of M 6 C carbides on the properties of two different PM tool steel coatings hot extruded with a 1.2714 steel bar. A carburization effect resulting from the W 2 C hard particles is responsible for an increase of the 1.2344 steel matrix hardness. The mechanical properties of the interface region between coating matrix and substrate are influenced by chemical interdiffusion of carbon and other alloying elements occurring during heat treatment.

  11. Hot isostatic-pressing diagrams for fine-particle beryllium powders

    International Nuclear Information System (INIS)

    Stoev, P.I.; Papirov, I.I.; Tikhinskij, G.F.; Vasil'ev, A.A.

    1995-01-01

    Charts of hot isostatic pressing (HIP) for 4 and 8 μm grain beryllium powders are plotted. Values of thickening rates are calculated and their dependences on HIP pressure and temperature are plotted. It is shown, that the relative density powder at growth of HIP pressure and temperature

  12. Experimental study of the form of "hot" steel particles on the ignition characteristics of liquid fuels

    Science.gov (United States)

    Zakharevich, Arkadiy V.

    2015-01-01

    The results of an experimental study of laws governing the ignition of liquid propellants (kerosene, diesel fuel and petroleum residue) by the single spherical steel particle heated to high temperatures are presented. Is carried out the comparison of the ignition delay times of the investigated flammable substances by the particles in the sphere and disk forms. It is established that the particle shape does not exert a substantial influence on the ignition process characteristics.

  13. Environmental radioactivity

    International Nuclear Information System (INIS)

    1985-01-01

    Outline summary of a report prepared under contract to the DOE: Research Priorities and UK Estuaries: An Overview identifying Research Requirements. Topics considered include the study of radionuclides released into the NE Irish Sea from BNFL, Sellafields, differences in the isotopic composition of stable lead in various sediments, the concentration and distribution of 'hot particles' derived from BNFL in the Irish Sea and adjacent areas, together with attempts to separate hot particles from sediments, and the composition and properties of marine surfaces in relation to uptake and loss of radionuclides, particularly in relation to the common mussel, Mytilus edulis. The problem of the presence of transuranic radionuclides in the bottom sediments of the NE Irish Sea is considered. Profiles of radioactivity are being developed at the shelf-break in order to determine the transfer of radionuclides from the sea surface to the deep sea and to coastal waters; organisms examined include phytoplankton, zooplankton and crustacea (shrimps). Organisms such as Acantharia have been examined to determine transfer of elements and radionuclides to skeletal structures eg Sr, Ba and Si. (U.K.)

  14. Simulation of << Hot >> particles formation during the accident at the Chernobyl NPP.; Modelirovanie obrazovaniya << goryachikh >> chastits vo vremya avarii na ChAEhS.

    Energy Technology Data Exchange (ETDEWEB)

    Kashparov, V A; Ivanov, Yu A; Prister, B S; Zvarich, S I; Protsak, V P; Khomutinin, Yu V; Polyakov, V D; Gudkov, A N; Kurepin, A D; Pazukhin, Eh M [Yinstitut Syil` s` kogospodars` koyi Radyiologyiyi, Kyiv (Ukraine); [Moskovskij Inzhenerno-Fizicheskij Inst., Moscow (Russian Federation)

    1994-12-31

    Dispersal composition of fuel << hot >> particles formed after oxidation of real Chernobyl nuclear fuel in the air for 3-21 hours at 673-1173 K was obtained. Mechanism of ruthenium particles formation during the accident (with dispersion of nuclear fuel) as a result of ruthenium oxidation, its sublimation, condensation and restoration on materials, presented by the elements of iron group was modelled. Dynamics of relative release of fission products, as well as of transuranium and transplutonium elements from real and modeled << hot >> particles at their high temperature incineration (1273-2273 K) in the inert media was measured.

  15. Heat and Mass Transfer at Hot Surface Ignition of Coal Particle

    OpenAIRE

    Glushkov Dmitrii O.; Kosintsev Andrey. G.; Shlegel Nikita E.; Vershinina Ksenia Yu.

    2015-01-01

    This paper describes the experimental investigations of the characteristics of heat and mass transfer during the conductive heating of a coal particle. We have established the boundary conditions of combustion initiation, and the conditions of thermal decomposition and solid fuel particles decay, characterized by the temperature of a heat source, and the duration of the respective stages.

  16. Statistical analysis for the radiological characterization of radioactive waste in particle accelerators

    CERN Document Server

    AUTHOR|(CDS)2085595; Luccioni, Catherine

    This thesis introduces a new method to characterize metallic very-low-level radioactive waste produced at the European Organization for Nuclear Research (CERN). The method is based on: 1. the calculation of a preliminary radionuclide inventory, which is the list of the radionuclides that can be produced when particles interact with a surrounding medium, 2. the direct measurement of γ emitters and, 3. the quantification of pure-α, pure-β and low-energy X-ray emitters, called difficult-to-measure (DTM) radionuclides, using the so-called scaling factor (SF), correlation factor (CF) and mean activity (MA) techniques. The first stage of the characterization process is the calculation of the radionuclide inventory via either analytical or Monte Carlo codes. Once the preliminary radionuclide inventory is obtained, the γ-emitting radionuclides are measured via γ-ray spectrometry on each package of the waste population. The major γ-emitter, called key nuclide (KN), is also identified. The scaling factor method e...

  17. Radioactive particles revealed by electron microscopy. Chemical and physical properties of radioactive particles in aerosol samples emitted during the early stage of Fukushima Dai-ichi Nuclear Power Plant accident

    International Nuclear Information System (INIS)

    Adachi, Kouji

    2015-01-01

    Water-insoluble radioactive materials emitted during an early stage of the Fukushima Dai-ichi Nuclear Power Plant accident in 2011 were identified, and their chemical and physical properties were characterized as particulate matters. In this report, studies on radioactive particles collected from filter samples in Tsukuba on March 14–15, 2011 are summarized. Their compositions, chemical states, sizes, shapes, crystallinity, and hygroscopicity were analyzed using microscopic analyses such as electron microscopy and synchrotron with a micro-beam. The results indicate that they include Cs, Fe, and Zn as well as elements from fission products and are water insoluble, spherical-glassy particles with ca. 2 micrometer in size. Understanding of their detailed properties is significant to improve the numerical models during the accident and to understand their occurrences in soil as well as the accident itself. In addition to the water-insoluble radioactive materials, water-soluble radioactive materials, which were likely emitted in different events during the accident, should be investigated to have comprehensive understanding of the accident and its environmental effects. More samples from various environments such as soil will be needed, and more detailed chemical and physical analyses will help to understand their formation process, influences on human health, and long term decrements in ambient conditions. (author)

  18. Determination of uranium isotopic composition and {sup 236}U content of soil samples and hot particles using inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Boulyga, S.F. [Radiation Physics and Chemistry Problems Inst., Minsk (Belarus); Becker, J.S. [Central Department for Analytical Chemistry, Research Centre Juelich (Germany)

    2001-07-01

    As a result of the accident at the Chernobyl nuclear power plant (NPP) the environment was contaminated with spent nuclear fuel. The {sup 236}U isotope was used in this study to monitor the spent uranium from nuclear fallout in soil samples collected in the vicinity of the Chernobyl NPP. Nuclear track radiography was applied for the identification and extraction of hot radioactive particles from soil samples. A rapid and sensitive analytical procedure was developed for uranium isotopic ratio measurement in environmental samples based on double-focusing inductively coupled plasma mass spectrometry (DF-ICP-MS) with a MicroMist nebulizer and a direct injection high-efficiency nebulizer (DIHEN). The performance of the DF-ICP-MS with a quartz DIHEN and plasma shielded torch was studied. Overall detection efficiencies of 4 x 10{sup -4} and 10{sup -3} counts per atom were achieved for {sup 238}U in DF-ICP-QMS with the MicroMist nebulizer and DIHEN, respectively. The rate of formation of uranium hydride ions UH{sup +}/U{sup +} was 1.2 x 10{sup -4} and 1.4 x 10{sup -4}, respectively. The precision of short-term measurements of uranium isotopic ratios (n = 5) in 1 {mu}g L{sup -1} NBS U-020 standard solution was 0.11% ({sup 238}U/{sup 235}U) and 1.4% ({sup 236}U/{sup 238}U) using a MicroMist nebulizer and 0.25% ({sup 235}U/{sup 238}U) and 1.9% ({sup 236}U/{sup 238}U) using a DIHEN. The isotopic composition of all investigated Chernobyl soil samples differed from those of natural uranium; i.e. in these samples the {sup 236}U/{sup 238}U ratio ranged from 10{sup -5} to 10{sup -3}. Results obtained with ICP-MS, {alpha}- and {gamma}-spectrometry showed differences in the migration properties of spent uranium, plutonium, and americium. The isotopic ratio of uranium was also measured in hot particles extracted from soil samples. (orig.)

  19. Flow Mapping in a Gas-Solid Riser via Computer Automated Radioactive Particle Tracking (CARPT)

    Energy Technology Data Exchange (ETDEWEB)

    Muthanna Al-Dahhan; Milorad P. Dudukovic; Satish Bhusarapu; Timothy J. O' hern; Steven Trujillo; Michael R. Prairie

    2005-06-04

    Statement of the Problem: Developing and disseminating a general and experimentally validated model for turbulent multiphase fluid dynamics suitable for engineering design purposes in industrial scale applications of riser reactors and pneumatic conveying, require collecting reliable data on solids trajectories, velocities ? averaged and instantaneous, solids holdup distribution and solids fluxes in the riser as a function of operating conditions. Such data are currently not available on the same system. Multiphase Fluid Dynamics Research Consortium (MFDRC) was established to address these issues on a chosen example of circulating fluidized bed (CFB) reactor, which is widely used in petroleum and chemical industry including coal combustion. This project addresses the problem of lacking reliable data to advance CFB technology. Project Objectives: The objective of this project is to advance the understanding of the solids flow pattern and mixing in a well-developed flow region of a gas-solid riser, operated at different gas flow rates and solids loading using the state-of-the-art non-intrusive measurements. This work creates an insight and reliable database for local solids fluid-dynamic quantities in a pilot-plant scale CFB, which can then be used to validate/develop phenomenological models for the riser. This study also attempts to provide benchmark data for validation of Computational Fluid Dynamic (CFD) codes and their current closures. Technical Approach: Non-Invasive Computer Automated Radioactive Particle Tracking (CARPT) technique provides complete Eulerian solids flow field (time average velocity map and various turbulence parameters such as the Reynolds stresses, turbulent kinetic energy, and eddy diffusivities). It also gives directly the Lagrangian information of solids flow and yields the true solids residence time distribution (RTD). Another radiation based technique, Computed Tomography (CT) yields detailed time averaged local holdup profiles at

  20. Anti-tumor effects of 125I radioactive particles implantation on transplantated tumor model of human breast cancer cells in nude mice

    International Nuclear Information System (INIS)

    Xiao Zhongdi; Liang Chunlin; Zhang Guoli; Jing Yue; Zhang Yucheng; Gai Baodong

    2011-01-01

    Objective: To study the anti-tumor effects of 125 I radioactive particles implantation on transplantated tumor model of human breast cancer cells in nude mice and clarify their anti-tumor mechanisms. Methods 120 nude mice transplantated with human breast cancer cells MCF-7 were randomly divided into 3 groups (n=40): 125 I radioactive particles implanted group, non-radioactive particles implanted group and non-particles implanted group. The articles were implanted into mice according to Pairs system principle. The expressions of Fas mRNA and protein and the activaties of caspase-3 and caspase-8 enzyme were detected by RT-PCR and Western blotting. The changes of cell cycle were detected by flow cytometry. Results: Compared with non-radioactive particles implanted group and non-particles implanted group, the size of cancer tissues in 125 I radioactive particles implanted group was reduced significantly (P 0 /G 1 phase was significantly increased (P 125 I radioactive particles into transplantated tumor model of human breast cancer cells can kill tumor cells, inhibit the growth cycle of tumor cells and induce the apoptosis of tumor cells in nude mice. (authors)

  1. Study of chemically synthesized ZnO nano particles under a bio template using radioactive ion beam

    CERN Multimedia

    This is a project proposal to study nano sized semiconductor ZnO system, useful in biology and medicinal purposes, using radioactive ion beam from ISOLDE. Doping of the nano particles with Cu, Cd and Ga ions (in their variable valancy states) are expected to impart changes in the electrical structure and properties in the said system under study. The morphological changes, chemical environment, micro structure, electrical and optical properties of the nano size particles of ZnO system (developed under a bio template of folic acid) after the interaction with radioactive ion beam will be studied. The provision of perturbed angular correlation (PAC) study with respect to the changes in chemical environment, where ever possible will be attempted.

  2. The development of a mobile hot cell facility for the conditioning of spent high activity radioactive sources (SHARS)

    International Nuclear Information System (INIS)

    Liebenberg, G.R.; Al-Mughrabi, M.

    2008-01-01

    The International Atomic Energy Agency (IAEA) Waste Technology Section with additional support from the U.S. National Nuclear Security Agency (NNSA) through the IAEA Nuclear Security Fund has funded the design, fabrication, evaluation, and testing of a portable hot cell intended to address the problem of disused SHARS in obsolete irradiation devices such as teletherapy heads and dry irradiators. The project is initially targeting the African continent but expected soon to expand to Latin America and Asia. This hot cell would allow source removal, characterization, consolidation, repackaging in modern storage shields, and secure storage of high risk SHARS at single sites in each IAEA Member State. The mobile hot cell and related equipment is transported in two shipping containers to a specific country where the following process takes place: 1-) Assembly of hot cell; 2-) Removal of SHARS from working shields, encapsulation into a stainless steel capsule and placement into a long term storage shield; 3-) Conditioning of any other spent sources the country may require; 4-) Dismantling of the hot cell; 5-) Shipping equipment out of country. The operation in a specific country is planned to be executed over a three week period. This presentation will discuss the development of the mobile hot cell facility as well as the demonstration of the state of readiness of the system for manipulation of SHARS and the planned execution of the conditioning operations. As a result of this project, excess SHARS could be managed safely and securely and possibly be more easily repatriated to their country of origin for appropriate final disposition. (author)

  3. Comparison Between Weisskopf and Thomas-Fermi Model for Particle Emission Widths from Hot Deformed Nuclei

    International Nuclear Information System (INIS)

    Surowiec, Aa.; Pomorski, K.; Schmitt, Ch.; Bartel, J.

    2002-01-01

    The emission widths Γ n and Γ p for emission of neutrons and protons are calculated within the Thomas-Fermi model, which we have recently developed, and are compared with those obtained in the usual Weisskopf approach for the case of zero angular momentum. Both methods yield quite similar results at small deformations, but rather important differences are observed for very deformed shapes, in particular for charged particles. A possible generalization of the model for emission of α-particles is also discussed. (author)

  4. The implantation of esophageal stent with radioactive 125I particles for advanced esophageal carcinomas: observation of therapeutic results

    International Nuclear Information System (INIS)

    Zhao Peng; Cui Hongkai; Yang Ruimin; Zhang Xizhong

    2011-01-01

    Objective: To investigate the therapeutic effect of the implantation of esophageal stent with radioactive 125 I particles in treating advanced esophageal carcinomas in aged patients. Methods: During the period from Sep. 2009 to Dec. 2010, implantation of esophageal stent was used to treat 43 aged patients with advanced esophageal cancer. Based on the patient's free will, the patients were divided into study group (n=18) receiving stent with 125 I particles and control group (n=25) receiving ordinary stent without 125 I particles. No significant difference in the age, the lesion length, the degree of stenosis and the disease stage existed between the study group and the control group. The technical success rate, the remission rate of dysphagia, the occurrence of complications and the mean survival time were calculated and analyzed. The results were compared between the two groups. Results: The technical success rate was 100% in both groups. The short-term remission rate of dysphagia was also 100% in both groups. The mean survival time in the study group and in the control group was 9.8 months and 4.8 months respectively, the difference between the two groups was statistically significant (P 0.05). Conclusion: This results of study indicate that for the treatment of advanced esophageal carcinomas the implantation of esophageal stent with radioactive 125 I particles can surely and markedly prolong the patient's survival time and relive the symptom of dysphagia. This technique is safe, feasible and effective in clinical practice. The use of the stent with radioactive 125 I particles is superior to the use of the traditional stent in treating patients with advanced esophageal cancer. (authors)

  5. Hot spots effect on infrared spectral luminance emitted by carbon under plasma particles impact

    International Nuclear Information System (INIS)

    Delchambre, E.; Reichle, R.; Mitteau, R.; Missirlian, M.; Gobin, R.

    2004-01-01

    During the last Tore Supra campaigns, an anomalous deformation in the near infrared spectrum of radiation has been observed on neutralizer underneath the Toroidal Pumped Limiter (TPL) on which we observed the growth of carbon layer. The consequence is the difficulty to asses the surface temperature of the components and the power loaded. Laboratory experiment has been performed, using an Electron Cyclotron Resonance (ECR) ions source, to reproduce, characterize and explain this phenomenon. The luminance emitted by Carbon Fibre Composite (CFC) and pyrolytic graphite, have been observed under 95 keV of H+ bombardments. The amplitude of the deformation was found to depend on the type of material used and the power density of the incident power loaded. This paper presents the possible hot spots explanation. The experimental luminance deformation is reproduced and these results are validated using a thermal model of dust in radiate equilibrium. (authors)

  6. Study of fine particles (PM2.5) during the dry-hot time in the Toluca city

    International Nuclear Information System (INIS)

    Rosendo G, V.; Aldape U, F.

    2007-01-01

    The first obtained results of the analysis of the fine fraction particulate material (PM 2.5 ) samples collected in the Toluca City are presented. The samples analyzed are part of a more extensive campaign that contemplates the low project the one which one carries out this work and that it integrates three climatic times (dry-hot, of rains and dry-cold time) with the purpose of investigating the events of contamination in one complete year. The obtained results correspond to the dry-hot time and its include mainly the database starting from which the temporal variation graphs were obtained, the correlations among elements and the enrichment factor, as well as a multiple correlation analysis. Additionally the gravimetry was measured. Its are not observed significant episodes, however, it was found an element of the traces order, little common in other atmospheric studies as it is arsenic. From the gravimetry it was deduced that the air quality standard of fine particle, it does not violate. (Author)

  7. Super-thermal particles in hot plasmas—Kinetic models, numerical solution strategies, and comparison to tokamak experiments

    International Nuclear Information System (INIS)

    Lauber, Philipp

    2013-01-01

    The excitation of collective instabilities by super-thermal particles in hot plasmas and the related transport processes attract increasing interest due to their fundamental challenges for theoretical models and their practical importance for burning fusion plasmas. In fact, the physics of a self-heated thermonuclear plasma due to fusion-born 3.5 MeV α-particles is one of the most important outstanding fundamental research topics on the way to a fusion power plant with magnetic confinement. Within the last 10 years significant advances on both the theoretical and the experimental sides have been made leading to a more detailed and quantitative understanding of fast-particle-driven instabilities. On the theoretical side, the crucial step was to move from fluid models for the plasma background with a hybrid kinetic expression for the energetic particles to a fully kinetic model for all the plasma species, i.e. background ions, background electrons, and fast ions. This improvement allows one to describe consistently the resonant interaction between global plasma waves such as shear Alfvén and Alfvén–acoustic waves, and the particles via Landau damping, i.e. the dynamics parallel to the magnetic background field. Also, mode conversion mechanisms require the inclusion of background ion scales in a kinetic, non-perturbative way. This accurate treatment of the plasma background leads not only to changes in the linear mode properties such as frequency, growth/damping rate, and mode structure but also influences the non-linear dynamics. Due to major advances, innovations and installation of diagnostics in present day experiments, this comparison can be carried out in a more detailed and comprehensive way than a few years ago. For example, the measurement of damping rates via active external antennas, the imaging of 2D mode structures via electron–cyclotron-emission spectroscopy, and the direct detection of escaping fast ions allow to diagnose various kinetic features

  8. Evolution of particle clouds around ablating pellets in magnetically confined hot plasmas

    International Nuclear Information System (INIS)

    Lengyel, L.L.

    1991-08-01

    Cryogenic hydrogen isotope pellets are being currently used for introducing fuel particles into the palsma interior in magnetic confinement fusion experiments. The spatial and time evolution of the initially low-temperature high-density particle clouds forming around such pellets are considered here, with particular attention being given to such physical processes as heating of the cloud by the energy fluxes carried by incident plasma particles, gasdynamic expansion with j vectorxB vector - produced deceleration in the transverse direction, finite-rate ionization and recombination processes, and magnetic field convection and diffusion. While the dynamic processes associated with the ionization and radial confinement processes are characterized by the relatively short Alfven time scale (μs range), the subsequent phase of axial expansion is associated with a notably larger hadrodynamic time scale defined by the heat input and gasdynamic expansion rates (ms range). Data stemming from experimental measurements in toroidal confinement machines are compared with results of model calculations. Some similarities with space plasmas are briefly discussed. (orig.)

  9. Application of the methods of scanning electron microscopy and X-ray microanalysis for 'hot particles' detection in the human lungs formed as a result of the Chernobyl accident

    International Nuclear Information System (INIS)

    Reva, Yu.P.; Portyanko, N.M.; Ivanov, A.S.; Chuchalin, A.G.

    1993-01-01

    The up-to-date approaches to 'hot particles' studying were applied in this investigation. A complex of morphological and physical-chemical methods make it possible to detect and identify the 'hot particles' in the autopsy material of the lungs from 2 males at the age 27 and 25, who participated in the liquidation of Chernobyl katastrophe consequences in 1986. The elemental and isotope content of these particles was the same as that of the 'hot particles' detected in the zone of the katstrophe. The results obtained make it possible to suppose that the 'hot particles' have been inhaled and existed for a long time in the human bodies. On the basis of these data we suppose that the 'hot particle' are the cause of respiratory and other systems disorders

  10. Hot Fuel Examination Facility (HFEF)

    Data.gov (United States)

    Federal Laboratory Consortium — The Hot Fuel Examination Facility (HFEF) is one of the largest hot cells dedicated to radioactive materials research at Idaho National Laboratory (INL). The nation's...

  11. The variation of organ doses with the particle size and chemical form of an inhaled radioactive aerosol

    International Nuclear Information System (INIS)

    Hunt, B.W.; Adams, N.; Reissland, J.A.

    1979-04-01

    In this report, radiation doses to organs are calculated as a function of the particle size of the inhaled radioactive material. Aerosols with an Activity Median Aerodynamic Diameter (AMAD) from 0.1 μm to 20 μm are considered and doses accumulated by various organs in periods ranging from 1 day to 70 years are given for 65 radionuclides. A computer program is used which calculates the transformations taking place in each organ per curie of inhaled nuclide from the basic radioactivity and metabolic data. The program also calculates the resulting doses both for the organ in which the transformations occur and from penetrating radiation emitted as a result of transformations in other organs. The effects of particle size and chemical form of the nuclides on the doses received by organs are discussed. Tables of doses accumulated by 10 specific organs and other organs together with effective whole body doses are given for particle sizes 0.1 μm, 1 μm and 10 μm (AMAD). (author)

  12. Generalized Boltzmann equations for on-shell particle production in a hot plasma

    International Nuclear Information System (INIS)

    Jakovac, A.

    2002-01-01

    A novel refinement of the conventional treatment of Kadanoff-Baym equations is suggested. In addition to the Boltzmann equation, another differential equation is used for calculating the evolution of the nonequilibrium two-point function. Although it was usually interpreted as a constraint on the solution of the Boltzmann equation, we argue that its dynamics is relevant to the determination and resummation of the particle production cut contributions. The differential equation for this new contribution is illustrated in the example of the cubic scalar model. The analogue of the relaxation time approximation is suggested. It results in the shift of the threshold location and in a smearing out of the nonanalytic threshold behavior of the spectral function. The possible consequences for the dilepton production are discussed

  13. Development of analytical techniques for studies on dispersion of actinides in the environment and characterization of environmental radioactive particles

    International Nuclear Information System (INIS)

    Jernstroem, J.

    2006-01-01

    Radioactive particles from three locations were investigated for elemental composition, oxidation states of matrix elements, and origin. Instrumental techniques applied to the task were scanning electron microscopy, X-ray and gamma-ray spectrometry, secondary ion mass spectrometry, and synchrotron radiation based microanalytical techniques comprising X-ray fluorescence spectrometry, X-ray fluorescence tomography, and X-ray absorption near-edge structure spectroscopy. Uranium-containing low activity particles collected from Irish Sea sediments were characterized in terms of composition and distribution of matrix elements and the oxidation states of uranium. Indications of the origin were obtained from the intensity ratios and the presence of thorium, uranium, and plutonium. Uranium in the particles was found to exist mostly as U(IV). Studies on plutonium particles from Runit Island (Marshall Islands) soil indicated that the samples were weapon fuel fragments originating from two separate detonations: a safety test and a low-yield test. The plutonium in the particles was found to be of similar age. The distribution and oxidation states of uranium and plutonium in the matrix of weapon fuel particles from Thule (Greenland) sediments were investigated. The variations in intensity ratios observed with different techniques indicated more than one origin. Uranium in particle matrixes was mostly U(IV), but plutonium existed in some particles mainly as Pu(IV), and in others mainly as oxidized Pu(VI). The results demonstrated that the various techniques were effectively applied in the characterization of environmental radioactive particles. An on-line method was developed for separating americium from environmental samples. The procedure utilizes extraction chromatography to separate americium from light lanthanides, and cation exchange to concentrate americium before the final separation in an ion chromatography column. The separated radiochemically pure americium fraction

  14. Development of analytical techniques for studies on dispersion of actinides in the environment and characterization of environmental radioactive particles

    Energy Technology Data Exchange (ETDEWEB)

    Jernstroem, J.

    2006-07-01

    Radioactive particles from three locations were investigated for elemental composition, oxidation states of matrix elements, and origin. Instrumental techniques applied to the task were scanning electron microscopy, X-ray and gamma-ray spectrometry, secondary ion mass spectrometry, and synchrotron radiation based microanalytical techniques comprising X-ray fluorescence spectrometry, X-ray fluorescence tomography, and X-ray absorption near-edge structure spectroscopy. Uranium-containing low activity particles collected from Irish Sea sediments were characterized in terms of composition and distribution of matrix elements and the oxidation states of uranium. Indications of the origin were obtained from the intensity ratios and the presence of thorium, uranium, and plutonium. Uranium in the particles was found to exist mostly as U(IV). Studies on plutonium particles from Runit Island (Marshall Islands) soil indicated that the samples were weapon fuel fragments originating from two separate detonations: a safety test and a low-yield test. The plutonium in the particles was found to be of similar age. The distribution and oxidation states of uranium and plutonium in the matrix of weapon fuel particles from Thule (Greenland) sediments were investigated. The variations in intensity ratios observed with different techniques indicated more than one origin. Uranium in particle matrixes was mostly U(IV), but plutonium existed in some particles mainly as Pu(IV), and in others mainly as oxidized Pu(VI). The results demonstrated that the various techniques were effectively applied in the characterization of environmental radioactive particles. An on-line method was developed for separating americium from environmental samples. The procedure utilizes extraction chromatography to separate americium from light lanthanides, and cation exchange to concentrate americium before the final separation in an ion chromatography column. The separated radiochemically pure americium fraction

  15. Towards a generalized Landau theory of quasi-particles for hot dense matter

    International Nuclear Information System (INIS)

    Leermakers, R.

    1985-01-01

    In this thesis it is tried to construct a Landau quasi-particle theory for relativistic systems, using field-theoretical methods. It includes a perturbative calculation of the pressure of a quark-gluon plasma. It reports the existence of a hitherto unnoticed plasmon contribution of the order g 3 due to transverse quasi-gluons. A new and Lorentz covariant formulation of the Landau theory is being developed, for a general relativistic system. A detailed calculation is presented of the observables of a quantum electrodynamical (QED) plasma, in lowest orders of perturbation theory. A transverse plasmon effect is discovered, both analytically and numerically. In addition, the analysis shows quasi-electrons and positrons to be stable excitations at any temperature. This is proven in all orders of perturbation theory. Along with a Landau theory for quark-gluon matter, a linearized kinetic equation is derived for the singlet quark distribution function, with a collision term for soft encounters between quasi-quarks. (Auth.)

  16. A comparative evaluation of drilling techniques for deposits containing free gold using radioactive gold particles as tracers

    International Nuclear Information System (INIS)

    Clarkson, R.

    1998-01-01

    In the summers of 1992 and 1994, the author designed and carried out a statistically valid research program using radioactivated gold particles as tracers (radiotracers). Two types of fully cased normal circulation (N / C) drills, two types of reverse circulation (R/C) drills and three solid auger drills were evaluated under a variety of field conditions. A frozen cylindrical core of compacted gravels containing four sizes ( 1.2, 0.60, 0.30 and 0.15 mm), (+l4,+28,+48and+100 mesh)of radiotracers was placed in 44 drill holes and the holes were re drilled. Scintillometers were used to track free gold losses due to spillage and blow-by around the collar (top) of the hole. Some gold particles were located in temporary traps in the drilling equipment and these particles would have contaminated subsequent samples (as carry-over). Several myths commonly attributed to particular drilling methods were dispelled. There was no significant difference between the recovery of the four sizes of gold particles with any of the drills tested. Observations and down-hole scintillometer records indicated that the free gold particles did not follow the bit down the hole and were either carried out of the hole or forced onto the sides of the hole at or above the depth at which the radioactive gold was positioned. A comparative evaluation of the results of these tests is presented

  17. X-ray emission of the hot gas and of accelerated particles in supernova remnants

    International Nuclear Information System (INIS)

    Acero, F.

    2008-09-01

    The current observations seem to support the theory that the shock wave of supernova remnants accelerate electrons (representing about 1% of cosmic rays) of the interstellar medium up to energies of about 10 15 eV. However there is still no solid evidence that supernova remnants also accelerate protons (major component of cosmic rays). The X-ray observations of those supernova remnants with the satellite XMM-Newton can provide crucial information on the acceleration mechanisms and on this population of accelerated particles. This thesis presents the X-ray analysis of the supernova remnants RX J1713.7-3946 and SN 1006 for which it has been shown that they accelerate electrons efficiently. As a result, these objects are very good targets to compare the theoretical models of acceleration to the observation. For the first object, I constructed through new XMM-Newton observations, the first high-angular resolution mosaic of the entire supernova remnant. I then compared the X- and gamma-ray emission of this object in order to understand the nature of the gamma-ray emission. This spectral and morphological comparison allowed me to discuss the two possible origins of the gamma-ray radiation (issued by electrons or by protons). For SN 1006, I studied the density of the ambient medium in which the shock wave propagates. This density is a key parameter for the hydrodynamical evolution of the remnant and for studying a future gamma-ray emission. The study of X-ray emission of the gas heated by the shock wave allowed me to better estimate of the value of the density so far poorly constrained for this object. (author)

  18. Multiple Δt strategy for particle image velocimetry (PIV) error correction, applied to a hot propulsive jet

    International Nuclear Information System (INIS)

    Nogueira, J; Lecuona, A; Nauri, S; Legrand, M; Rodríguez, P A

    2009-01-01

    PIV (particle image velocimetry) is a measurement technique with growing application to the study of complex flows with relevance to industry. This work is focused on the assessment of some significant PIV measurement errors. In particular, procedures are proposed for estimating, and sometimes correcting, errors coming from the sensor geometry and performance, namely peak-locking and contemporary CCD camera read-out errors. Although the procedures are of general application to PIV, they are applied to a particular real case, giving an example of the methodology steps and the improvement in results that can be obtained. This real case corresponds to an ensemble of hot high-speed coaxial jets, representative of the civil transport aircraft propulsion system using turbofan engines. Errors of ∼0.1 pixels displacements have been assessed. This means 10% of the measured magnitude at many points. These results allow the uncertainty interval associated with the measurement to be provided and, under some circumstances, the correction of some of the bias components of the errors. The detection of conditions where the peak-locking error has a period of 2 pixels instead of the classical 1 pixel has been made possible using these procedures. In addition to the increased worth of the measurement, the uncertainty assessment is of interest for the validation of CFD codes

  19. Multiple Δt strategy for particle image velocimetry (PIV) error correction, applied to a hot propulsive jet

    Science.gov (United States)

    Nogueira, J.; Lecuona, A.; Nauri, S.; Legrand, M.; Rodríguez, P. A.

    2009-07-01

    PIV (particle image velocimetry) is a measurement technique with growing application to the study of complex flows with relevance to industry. This work is focused on the assessment of some significant PIV measurement errors. In particular, procedures are proposed for estimating, and sometimes correcting, errors coming from the sensor geometry and performance, namely peak-locking and contemporary CCD camera read-out errors. Although the procedures are of general application to PIV, they are applied to a particular real case, giving an example of the methodology steps and the improvement in results that can be obtained. This real case corresponds to an ensemble of hot high-speed coaxial jets, representative of the civil transport aircraft propulsion system using turbofan engines. Errors of ~0.1 pixels displacements have been assessed. This means 10% of the measured magnitude at many points. These results allow the uncertainty interval associated with the measurement to be provided and, under some circumstances, the correction of some of the bias components of the errors. The detection of conditions where the peak-locking error has a period of 2 pixels instead of the classical 1 pixel has been made possible using these procedures. In addition to the increased worth of the measurement, the uncertainty assessment is of interest for the validation of CFD codes.

  20. Contribution to the study of tracheobronchial and pulmonary deposits in 52 subjects after inhalation of radioactive particles

    International Nuclear Information System (INIS)

    Lange, Pierre.

    1980-03-01

    Particle deposits in the bronchopulmonary system can lead to three main types of disorder: pneumoconioses, bronchial cancers and most chronic bronchopulmonary diseases. The study of deposition is useful for the prevention, diagnosis and treatment of these illnesses. The air-borne contaminants laid down are cleared by different mechanisms corresponding roughly to distinct anatomical regions. Short-term clearance, known as tracheobronchial (TB) takes place in a few hours, while long-term clearance from the deep lung is much slower: according to the International Radiological Protection Commission, 60% of particles deposited in the bronchiolo-alveolar region take more than 500 days to eliminate. It is useful therefore to known in what proportions the particles are fixed in the tracheobronchial region and on the deep lung. This was the purpose of the present work. The distribution of the deposit between these two regions was measured in 52 subjects having breathed in radioactive particles (indium 111). A functional respiratory study was conducted at the same time to find out whether the two sets of experimental data are related in any way [fr

  1. Process to decontaminate a superficial soil layer contaminated with radioactive particles and decontaminating solution

    International Nuclear Information System (INIS)

    Jouve, A.; Mary, N.

    1993-01-01

    The process consists to dissolve a micronised powder of anionic and crosslinked polyacrilamide, to spray the obtained decontamination solution on the floor to be traited allowing to dry to form a dry polyacrilamide film, to rehydrate the film by spraying with water and to recover the film bonded to the floor particles and the polluting particles by cleaning means. 1 fig

  2. Trace elements and radioactivity in aerosol particles, produced in the area of Ptolemais (Greece)

    International Nuclear Information System (INIS)

    Kallithrakas-Kontos, N.; Zoumi, K.; Nikolakaki, S.; Kritidis, P.

    1998-01-01

    Most of the Greek lignite power plants have been installed in the area of Ptolemais, and a major part of them during the period 1981-1990. Aerosol filters collected in the first and the last years of the decade have been analysed for trace elements as well as for radioactivity (total beta) content. Analysis was performed by radioisotope excited X-ray fluorescence, and 17 elements were determined. A special interest is focused on lead concentrations, an element whose environmental concentrations are regulated by the Greek law; the results for lead were validated by atomic absorption spectrometry. Trace element and radioactivity levels were found significantly lower than the current limit. Enrichment factors and correlation among the analysed elements were also estimated. (author)

  3. Laboratory study of the radioactivity from fission products in microscopic fallout particles

    International Nuclear Information System (INIS)

    Smith, H.A.; Ward, T.E.; Wesick, J.

    1978-01-01

    An experiment is described wherein simple γ-ray detection and analysis techniques were utilized to study the radioactivity in local precipitation. Gamma spectra from filtered particulate, evaporation residue, and water from a sample of freshly fallen snow were counted, and the relative amount of several radionuclides present were identified. These data show that several isotopes produced in the recent Chinese nuclear detonation (Lop Nor testing ground, Sinkiang Province, 17 November 1976) are observable. Furthermore the data are sufficient to estimate the date of the detonation and to determine some of the characteristics of the explosion

  4. Comparative discussion on some measurements of the atmospheric natural radioactivity and pollution with coal smoke particles

    International Nuclear Information System (INIS)

    Zoran, M.

    1977-01-01

    The results of measuring the natural radioactivity and coal smoke pollution are discussed for two sites in an industrial town, as well as for two heights at the same site, in connection with large scale and local atmospheric stability. The effects of the radiation fog upon the radon daughters acumulation near the ground are examined in some detail. By comparing the pollutant diurnal variations during two periods of similar atmospheric stability in autumn, respectively in winter, the contribution from the dwelling coal heating has been estimated to be about half of the total pollution in the town. (author)

  5. A guide to radiation and radioactivity levels near high energy particle accelerators

    International Nuclear Information System (INIS)

    Sullivan, A.H.

    1992-01-01

    An estimate of likely radiation and radioactivity levels is needed at the design stage of an accelerator for deciding the radiation safety features to be incorporated in the infrastructure of the machine and for predicting where radiation damage possibilities will have to be taken into account. Both these aspects can have a significant influence on the machine layout and cost. Failure to make a reasonable assessment at the right time may have far reaching consequences for future costs. The purpose of this guide is to bring together basic data and methods that have been found useful in assessing radiation situations around accelerators and to provide a practical means of arriving at the radiation and induced radioactivity levels that could occur under a wide variety of circumstances. An attempt is made to present the information in a direct and unambiguous way with sufficient confidence that the necessity for large safety factors is avoided. In many cases assumptions and simplifications have been made and reliance placed on extrapolating from experimental data into regions where the basic physics is too complicated to make meaningful absolute calculations. Wherever possible such extrapolations have been tied to real or otherwise acceptable data originating from independent sources. (Author)

  6. Work in progress: transcatheter embolization of renal cell carcinoma with radioactive infarct particles

    International Nuclear Information System (INIS)

    Lang, E.K.; Sullivan, J.; DeKernion, J.B.

    1983-01-01

    Treatment by radioactive infarct implant is advocated for patients who have renal cell carcinoma with distant metastases. The radioactive infarct implants were placed into the primary tumor, and when feasible into metastases, by transcatheter embolization. Metastases to the skeleton, liver, lungs, adrenals, and retroperitoneal muscles were also seeded; metastases to the central nervous system, pancreas, and spleen, as well as most pulmonary metastases, proved inaccessible to this approach. The effectiveness of this treatment modality was shown by improved cumulative survival rates (59% for patients with metastases and at risk at two years and 50% for those at risk at five years). The best results were obtained when treating patients who had skeletal metastases (90% survival of those at risk at two years and 60% at five years). Measurable palliation factors, such as decrease in the size of the primary lesion, weight gain, and control of bleeding and pain, were indicators of treatment response and were observed in the majority of patients. Remissions were signaled by weight gain, normalization of the erythrocyte sedimentation rate, and disappearance or decrease of tumor markers. Some evidence suggests that the salutary results may be based on significant reduction of tumor burden, temporary local control of tumor, and improved general immunocompetence

  7. Silicon surface barrier detector and study of energy spectrum of alpha particles from radioactive source

    International Nuclear Information System (INIS)

    Verma, S.D.; Sinha, Vijaya

    1986-01-01

    The principles of working of three commonly used radiation detectors, namely ionization chambers, scintillation counters with photomultiplier tube (PMT) systems and semiconductor detectors are briefly discussed. Out of the semiconductor detectors, the silicon surface barrier (SSB) detector has distinct advantages for detection of radiations, alpha particles in particular. The experimental setup to obtain the energy spectrum of alpha particles from 241 Am source using SSB fabricated in the Physics Department of Gujarat University, Ahmedabad is described. Its performance is compared with scintillation counter using PMT. SSB detector shows a sharp peak of #approx # 3 per cent energy resolution. The factors affecting the peak, namely, electronic noise, source dependent factors and detector-dependent factors are discussed. A method of calibrating SSB detectors based on energy loss mechanism of alpha particles in thin absorbers is described. Applications of such detectors are indicated. (M.G.B.)

  8. Evaluation of physicochemical properties of radioactive cesium in municipal solid waste incineration fly ash by particle size classification and leaching tests.

    Science.gov (United States)

    Fujii, Kengo; Ochi, Kotaro; Ohbuchi, Atsushi; Koike, Yuya

    2018-07-01

    After the Fukushima Daiichi-Nuclear Power Plant accident, environmental recovery was a major issue because a considerable amount of municipal solid waste incineration (MSWI) fly ash was highly contaminated with radioactive cesium. To the best of our knowledge, only a few studies have evaluated the detailed physicochemical properties of radioactive cesium in MSWI fly ash to propose an effective method for the solidification and reuse of MSWI fly ash. In this study, MSWI fly ash was sampled in Fukushima Prefecture. The physicochemical properties of radioactive cesium in MSWI fly ash were evaluated by particle size classification (less than 25, 25-45, 45-100, 100-300, 300-500, and greater than 500 μm) and the Japanese leaching test No. 13 called "JLT-13". These results obtained from the classification of fly ash indicated that the activity concentration of radioactive cesium and the content of the coexisting matter (i.e., chloride and potassium) temporarily change in response to the particle size of fly ash. X-ray diffraction results indicated that water-soluble radioactive cesium exists as CsCl because of the cooling process and that insoluble cesium is bound to the inner sphere of amorphous matter. These results indicated that the distribution of radioactive cesium depends on the characteristics of MSWI fly ash. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Localisation and identification of radioactive particles in solid samples by means of a nuclear track technique

    International Nuclear Information System (INIS)

    Boehnke, Antje; Treutler, Hanns-Christian; Freyer, Klaus; Schubert, Michael; Holger Weiss

    2005-01-01

    This study is aimed to develop a generally applicable methodology of investigation that can be used for the localisation of single alpha-active particles in solid samples, such as industrial dust or natural soils, sediments and rocks by autoradiography using solid-state nuclear track detectors. The developed technique allows the detection of local enrichments of alpha-emitters in any solid material. The results of such an investigation are of interest from technical, biological and environmental points of view. The idea behind the methodology is to locate the position of alpha-active spots in a sample by attaching the track detector to the sample in a defined manner, thoroughly described in the paper. The located alpha-active particles are subsequently analysed by an electron microscope and an electron microprobe. An example of the application of this methodology is also given. An ultra-fine -grained ore-processing residue, which causes serious environmental pollution in the respective mining district and thus limits possible land use and affects quality of life in the area, was examined using the described technique. The investigation revealed considerable amounts of alpha-active particles in this material

  10. High Power Molten Targets for Radioactive Ion Beam Production: from Particle Physics to Medical Applications

    CERN Document Server

    De Melo Mendonca, T M

    2014-01-01

    Megawatt-class molten targets, combining high material densities and good heat transfer properties are being considered for neutron spallation sources, neutrino physics facilities and radioactive ion beam production. For this last category of facilities, in order to cope with the limitation of long diffusion times affecting the extraction of short-lived isotopes, a lead-bismuth eutectic (LBE) target loop equipped with a diffusion chamber has been proposed and tested offline during the EURISOL design study. To validate the concept, a molten LBE loop is now in the design phase and will be prototyped and tested on-line at CERN-ISOLDE. This concept was further extended to an alternative route to produce 1013 18Ne/s for the Beta Beams, where a molten salt loop would be irradiated with 7 mA, 160 MeV proton beam. Some elements of the concept have been tested by using a molten fluoride salt static unit at CERNISOLDE. The investigation of the release and production of neon isotopes allowed the measurement of the diffu...

  11. Effect of uncertainty in nasal airway deposition of radioactive particles on effective dose

    Energy Technology Data Exchange (ETDEWEB)

    Guilmette, R.A.; Birchall, A.; Jarvis, N.S

    1998-07-01

    In the current ICRP human respiratory tract (RT) model (ICRP Publication 66), the deposition of particles in various regions of the RT during natural breathing is modelled by considering the RT as a series of filters, resulting in deposition probabilities for distal portions of the RT being dependent on those of the proximal segments. Thus, uncertainties in regional deposition in proximal segments of the RT are reflected or propagated in uncertainties in deposition in the distal segments of the lung. Experimental data on aerosol particle deposition have demonstrated significant variability in nasal airway (NA) deposition for different individuals studied. This report summarises the impact of introducing variability in NA deposition efficiency on the calculation of effective doses using the ICRP 66 model for selected radionuclides. The computer software LUDEP, modified for this purpose, was used to customise deposition patterns, and effective doses were calculated for several radionuclides ({sup 111}In, {sup 106}Ru, {sup 60}Co, {sup 210}Po, {sup 238}U and {sup 239}Pu) chosen to represent isotopes with various decay schemes and half-lives. The results indicated significant but particle-size-specific effects of assumed NA deposition efficiencies on the calculated effective doses, which varied typically by factors of five to six. The majority of the variability was associated with direct effects on deposition patterns, but in some cases, alterations of radiation dose distribution within the various target organs also contributed to the variability. These results provide a basis for evaluating uncertainties due to inter-individual differences in deposition patterns for radiation protection and risk analysis. (author)

  12. Charged particle transport and extraction studies in the NSCL gas cell for stopping radioactive fragments

    International Nuclear Information System (INIS)

    Facina, M.; Bachelet, C.; Block, M.; Bollen, G.; Davies, D.; Folden, C.M.; Guenaut, C.; Huikari, J.; Kwan, E.; Morrissey, D.J.; Pang, G.K.; Prinke, A.; Ringle, R.; Savory, J.; Schury, P.; Schwarz, S.; Sumithrarachchi, C.; Sun, T.

    2008-01-01

    The NSCL gas-stopping station thermalizes high-energy projectile fragments for study in the low energy beam and ion trap (LEBIT) facility. The stopping and extraction of fast beams has been studied extensively and the extracted short-lived ions have been used in a series of mass measurements of exotic nuclei. Particle-in-cell simulations of ion drift in the gas cell have been performed. In the present paper calculation results are presented and compared to experimental data obtained with neutron-deficient and neutron-rich As and Se isotopes recently measured at LEBIT. Good agreement between the theoretical and experimental extraction efficiency was found.

  13. Ventilation conditions and atmospheric characteristics of a laboratory uranium mine. Application to the distribution of radioactive particles in the respiratory tract

    International Nuclear Information System (INIS)

    Duport, Philippe.

    1978-09-01

    The CEA laboratory uranium mine and the characteristics of its ventilation are described. A method of measuring air flows based on the determination of a tracer gas was developed. Variations of radon concentrations and of its daughter products concentrations and radioactive equilibrium were observed as a function of the various ventilation rates. Particle size distribution of radioactive aerosols was studied in the laboratory mine when unoperated. Several methods of evaluation of the free fraction were compared, and the application of the laws of aerosol physics to the production of radioactive aerosols in a mine was investigated. A study of radioactive ions showed that the usual equations of atmospheric electricity could be applied to charged radioactive aerosols in a mine. Finally an experimental method was developed in order to directly examine the deposit of an aerosol labelled by radon daughter products in the respiratory tract of animals. The experimental results obtained with aerosols in the particle size range 5.10 -8 - 5.10 -6 were compared to the theoretical data derived from models published in the literature [fr

  14. Radioactive rare earths from fallout for study of particle movement in the sea

    International Nuclear Information System (INIS)

    Sugihara, Thomas T.; Bowen, Vaughan T.

    1962-01-01

    As part of an extensive study of the distribution of long-lived radionuclides from fallout in the Atlantic Ocean, a large number of measurements of cerium-144 and promethium-147 concentration have been made. Comparison of these concentrations as they vary both horizontally and vertically, with simultaneously measured concentrations of strontium-90, indicates that the rare earths are generally depleted in surface water, by comparison with the nuclides known to be soluble. This observation, coupled with frequent observation of rare-earth enrichment at depth, leads us to postulate rapid vertical transport of rare earths by attachment to particles undergoing sedimentation. This is completely plausible in terms of the 'radiocolloid' behaviour generally observed for rare earths at sea-water pH. An attempt is made to interpret this study in the overall picture of the marine geochemistry of the trivalent cations, as well as to emphasize the unique and generally useful aspects of the fallout tracer experiment. (author) [fr

  15. Development of an advanced radioactive airborne particle monitoring system for use in early warning networks.

    Science.gov (United States)

    Baeza, A; Corbacho, J A; Caballero, J M; Ontalba, M A; Vasco, J; Valencia, D

    2017-09-25

    Automatic real-time warning networks are essential for the almost immediate detection of anomalous levels of radioactivity in the environment. In the case of Extremadura region (SW Spain), a radiological network (RARE) has been operational in the vicinity of the Almaraz nuclear power plant and in other areas farther away since 1992. There are ten air monitoring stations equipped with Geiger-Müller counters in order to evaluate the external ambient gamma dose rate. Four of these stations have a commercial system that provides estimates of the total artificial alpha and beta activity concentrations in aerosols, and of the 131 I activity (gaseous fraction). Despite experience having demonstrated the benefits and robustness of these commercial systems, important improvements have been made to one of these air monitoring systems. In this paper, the analytical and maintenance shortcomings of the original commercial air monitoring system are described first; the new custom-designed advanced air monitoring system is then presented. This system is based mainly on the incorporation of gamma spectrometry using two scintillation detectors, one of NaI:Tl and the other of LaBr 3 :Ce, and compact multichannel analysers. Next, a comparison made of the results provided by the two systems operating simultaneously at the same location for three months shows the advantages of the new advanced air monitoring system. As a result, the gamma spectrometry analysis allows passing from global alpha and beta activity determinations due to artificial radionuclides in aerosols, and the inaccurate measurement of the gaseous 131 I activity concentration, to the possibility of identifying a large number of radionuclides and quantifying each of their activity concentrations. Moreover, the new station's dual capacity is designed to work in early warning monitoring mode and surveillance monitoring mode. This is based on custom developed software that includes an intelligent system to issue the

  16. Evaluation of a process for the decontamination of radioactive hotspots due to activated stellite particles

    International Nuclear Information System (INIS)

    Subramanian, Veena; Chandramohan, Palogi; Chandran, Sinu; Srinivasan, Madapusi P.; Rangarajan, Srinivasan; Velmurugan, Sankaralingam; Narasimhan, Sevilmedu V.

    2011-01-01

    Some of the Indian pressurized heavy water reactors (PHWRs) which use Stellite balls in the ball and screw mechanism of the adjustor rod drive mechanism in the moderator circuit have encountered high radiation fields in the moderator system due to 60 Co. Release of particulate Stellite is responsible for the hotspots in addition to the general uniform contamination of internal surfaces with 60 Co. Extensive laboratory studies have shown that it is possible to dissolve these Stellite particles by adopting a three-step redox process with permanganic acid as the oxidizing agent. These investigations with inactive Stellite in powder form helped to optimize the process conditions. Permanganic acid was found to have the highest dissolution efficiency as compared to alkaline and nitric acid permanganate. The susceptibility of Stellite to corrode or dissolve was found to depend on the concentration of the permanganate, pH and temperature of the process and microstructure of the Stellite alloy. This process was evaluated for its effectiveness on components from nuclear power plants. Component decontamination was carried out on adjustor rod drive assemblies which had 60 Co activity due to Stellite particles with the radiation field ranging from 3 R . h -1 to 20 R . h -1 . They were subjected to decontamination with permanganic acid as the oxidizing agent, followed by citric acid and a solution containing ethylenediaminetetraacetic acid, ascorbic acid and citric acid in a 4:3:3 ratio by weight as the reducing formulation. In the first trial, one adjustor rod drive mechanism was subjected to decontamination. After two cycles of treatment, an average decontamination factor (DF) of 6.8, with a maximum DF of 11.7, was achieved. The same process but with one cycle was repeated on eight more adjustor rod drive mechanisms. 60 Co activity in the range of 13-93 mCi was removed from these adjustor rods. Loose contamination of the order of 30 000-40 000 decays per min and cm 2 observed

  17. Evaluation of a process for the decontamination of radioactive hotspots due to activated stellite particles

    International Nuclear Information System (INIS)

    Subramanian, V.; Chandramohan, P.; Srinivasan, M.P.; Rangarajan, S.; Velmurugan, S.; Narasimhan, S.V.; Khandelwal, R.C.

    2010-01-01

    Some of the Indian PHWRs which used stellite balls in the ball and screw mechanism of the adjustor rod drive mechanism in the moderator circuit encountered high radiation field in moderator system due to 60 Co. Release of particulate stellite was responsible for the hotspots besides the general uniform contamination of internal surfaces with 60 Co. Extensive laboratory studies have shown that it is possible to dissolve these stellite particles by adopting a three step redox process with permanganic acid as the oxidizing agent. These investigations with inactive stellite in powder form helped to optimize the process conditions. Permanganic acid was found to have the highest dissolution efficiency as compared to alkaline and nitric acid permanganate. The concentration of the permanganate was also found to be an important factor in deciding the efficiency of the dissolution of stellite. The efficiency of dissolution as a function of permanganic acid concentration showed a maximum. This process was evaluated for its effectiveness on components from nuclear power plants. Component decontamination was carried out on adjustor rod drive assemblies which had 60 Co activity due to stellite particles with the radiation field ranging from 3 R/h to 20 R/h. They were subjected to decontamination with permanganic acid as oxidizing agent, followed by citric acid and a solution containing EDTA, ascorbic acid and citric acid in 4:3:3 ratio by weight (EAC) as reducing formulations. A test rig was fabricated for this purpose. In the first trial, one adjustor rod drive mechanism was subjected to decontamination. After two cycles of treatment, an average decontamination factor (DF) of 6.8, with a maximum DF of 11.7 was achieved. The same process but one cycle was repeated on eight more adjustor rod drive mechanisms. 60 Co activity in the range of 13 - 93 mCi was removed from these adjustor rods. Loose contamination of the order of 30000 - 40000 dpm/cm 2 observed before decontamination

  18. Evaluation of a process for the decontamination of radioactive hotspots due to activated stellite particles

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, Veena; Chandramohan, Palogi; Chandran, Sinu; Srinivasan, Madapusi P.; Rangarajan, Srinivasan; Velmurugan, Sankaralingam; Narasimhan, Sevilmedu V. [BARC Facilities, Kalpakkam, Tamil Nadu (India). Water and Steam Chemistry Div.

    2011-06-15

    Some of the Indian pressurized heavy water reactors (PHWRs) which use Stellite balls in the ball and screw mechanism of the adjustor rod drive mechanism in the moderator circuit have encountered high radiation fields in the moderator system due to {sup 60}Co. Release of particulate Stellite is responsible for the hotspots in addition to the general uniform contamination of internal surfaces with {sup 60}Co. Extensive laboratory studies have shown that it is possible to dissolve these Stellite particles by adopting a three-step redox process with permanganic acid as the oxidizing agent. These investigations with inactive Stellite in powder form helped to optimize the process conditions. Permanganic acid was found to have the highest dissolution efficiency as compared to alkaline and nitric acid permanganate. The susceptibility of Stellite to corrode or dissolve was found to depend on the concentration of the permanganate, pH and temperature of the process and microstructure of the Stellite alloy. This process was evaluated for its effectiveness on components from nuclear power plants. Component decontamination was carried out on adjustor rod drive assemblies which had {sup 60}Co activity due to Stellite particles with the radiation field ranging from 3 R . h{sup -1} to 20 R . h{sup -1}. They were subjected to decontamination with permanganic acid as the oxidizing agent, followed by citric acid and a solution containing ethylenediaminetetraacetic acid, ascorbic acid and citric acid in a 4:3:3 ratio by weight as the reducing formulation. In the first trial, one adjustor rod drive mechanism was subjected to decontamination. After two cycles of treatment, an average decontamination factor (DF) of 6.8, with a maximum DF of 11.7, was achieved. The same process but with one cycle was repeated on eight more adjustor rod drive mechanisms. {sup 60}Co activity in the range of 13-93 mCi was removed from these adjustor rods. Loose contamination of the order of 30 000-40 000

  19. Evaluation of a process for the decontamination of radioactive hotspots due to activated stellite particles

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, V.; Chandramohan, P.; Srinivasan, M.P.; Rangarajan, S.; Velmurugan, S.; Narasimhan, S.V., E-mail: svn@igcar.gov.in [BARC Facilities, Water and Steam Chemistry Div., Kalpakkam, Tamilnadu (India); Khandelwal, R.C. [Kakrapara Atomic Power Station, KAPS, Surat, Gujarat (India)

    2010-07-01

    Some of the Indian PHWRs which used stellite balls in the ball and screw mechanism of the adjustor rod drive mechanism in the moderator circuit encountered high radiation field in moderator system due to {sup 60}Co. Release of particulate stellite was responsible for the hotspots besides the general uniform contamination of internal surfaces with {sup 60}Co. Extensive laboratory studies have shown that it is possible to dissolve these stellite particles by adopting a three step redox process with permanganic acid as the oxidizing agent. These investigations with inactive stellite in powder form helped to optimize the process conditions. Permanganic acid was found to have the highest dissolution efficiency as compared to alkaline and nitric acid permanganate. The concentration of the permanganate was also found to be an important factor in deciding the efficiency of the dissolution of stellite. The efficiency of dissolution as a function of permanganic acid concentration showed a maximum. This process was evaluated for its effectiveness on components from nuclear power plants. Component decontamination was carried out on adjustor rod drive assemblies which had {sup 60}Co activity due to stellite particles with the radiation field ranging from 3 R/h to 20 R/h. They were subjected to decontamination with permanganic acid as oxidizing agent, followed by citric acid and a solution containing EDTA, ascorbic acid and citric acid in 4:3:3 ratio by weight (EAC) as reducing formulations. A test rig was fabricated for this purpose. In the first trial, one adjustor rod drive mechanism was subjected to decontamination. After two cycles of treatment, an average decontamination factor (DF) of 6.8, with a maximum DF of 11.7 was achieved. The same process but one cycle was repeated on eight more adjustor rod drive mechanisms. {sup 60}Co activity in the range of 13 - 93 mCi was removed from these adjustor rods. Loose contamination of the order of 30000 - 40000 dpm/cm{sup 2} observed

  20. Problems of dosimetry and risk assessment associated with inhalation of fuel particles

    International Nuclear Information System (INIS)

    Repin, V.S.; Nechaev, S.Y.; Bondarenko, O.A.; Bykorez, A.I.; Kononenko, L.I.

    1995-01-01

    This work deals with the problems of dosimetry and risk assessment associated with inhalation of fuel particles. Radioactive emission parameters and potential for assessment of the lung cancer risk with inhalation penetration of hot particles are described. (O.L.). 10 refs., 9 figs., 1 tab

  1. Study of a ;hot; particle with a matrix of U-bearing metallic Zr: Clue to supercriticality during the Chernobyl nuclear accident

    Science.gov (United States)

    Pöml, P.; Burakov, B.

    2017-05-01

    This paper is dedicated to the 30th anniversary of the severe nuclear accident that occurred at the Chernobyl NPP on 26 April 1986. A detailed study on a Chernobyl "hot" particle collected from contaminated soil was performed. Optical and electron microscopy, as well as quantitative x-ray microbeam analysis methods were used to determine the properties of the sample. The results show that the particle (≈ 240 x 165 μm) consists of a metallic Zr matrix containing 2-3 wt. % U and bearing veins of an U,Nb admixture. The metallic Zr matrix contains two phases with different amounts of O with the atomic proportions (U,Zr,Nb)0.73O0.27 and (U,Zr,Nb)0.61O0.39. The results confirm the interaction between UO2 fuel and zircaloy cladding in the reactor core. To explain the process of formation of the particle, its properties are compared to laboratory experiments. Because of the metallic nature of the particle it is concluded that it must have formed during a very high temperature (> 2400∘C) process that lasted for only a very short time (few microseconds or less); otherwise the particle should have been oxidised. Such a rapid very high temperature process indicates that at least part of the reactor core could have been supercritical prior to an explosion as it was previously suggested in the literature.

  2. Exposure to Particle Matters and Hazardous Volatile Organic Compounds in Selected Hot Spring Hotels in Guangdong, China

    Directory of Open Access Journals (Sweden)

    Qiusheng He

    2016-04-01

    Full Text Available In Guangdong province, many hot springs were exploited and developed into popular places for tourist. In addition, hotels have been set up near hot spring sites to attract people, including local citizens, to spend their spare time inside these so-called “spring hotels”. In our study, indoor air quality was investigated in four hot spring hotels in Guangdong province, China. Measured indoor pollutants included CO2, CO, PM10, PM2.5 and Volatile Organic Compounds (VOCs. As the result show, high concentrations of carbon dioxide might be attributed to poor ventilation; and the variations of indoor PM10, PM2.5 concentrations were related to occupants’ activities. Alpha-pinene and toluene were the most common VOC species in the hot spring hotels other than monocyclic aromatic hydrocarbons like Benzene, Toluene, Ethylbenzene and Xylenes (BTEX, which were at medium levels among the reported indoor pollutants. High cancer risk of benzene in the newly decorated rooms should be seriously taken into consideration in the future. Indoor to Outdoor air concentration ratios (I/O for CO2 and VOCs were higher than 1, indicating their strong indoor sources. Negative correlations were found between indoor CO2 and all the other compounds, and VOCs were shown to be significantly correlated (p < 0.01 to each other, including aromatic hydrocarbons and mono-terpenes. For indoor and outdoor air compounds, correlation coefficients among all compounds did not show a significant correlation, which indicated that these pollutants had different sources. Principal components analysis by SPSS showed that indoor materials, inhabitants’ activities and respiration, cleaning products and outdoor sources were the main sources of indoor detected pollutants in hot spring hotels.

  3. Leakage of radioactive materials from particle accelerator facilities by non-radiation disasters like fire and flooding and its environmental impacts

    Science.gov (United States)

    Lee, A.; Jung, N. S.; Mokhtari Oranj, L.; Lee, H. S.

    2018-06-01

    The leakage of radioactive materials generated at particle accelerator facilities is one of the important issues in the view of radiation safety. In this study, fire and flooding at particle accelerator facilities were considered as the non-radiation disasters which result in the leakage of radioactive materials. To analyse the expected effects at each disaster, the case study on fired and flooded particle accelerator facilities was carried out with the property investigation of interesting materials presented in the accelerator tunnel and the activity estimation. Five major materials in the tunnel were investigated: dust, insulators, concrete, metals and paints. The activation levels on the concerned materials were calculated using several Monte Carlo codes (MCNPX 2.7+SP-FISPACT 2007, FLUKA 2011.4c and PHITS 2.64+DCHAIN-SP 2001). The impact weight to environment was estimated for the different beam particles (electron, proton, carbon and uranium) and the different beam energies (100, 430, 600 and 1000 MeV/nucleon). With the consideration of the leakage path of radioactive materials due to fire and flooding, the activation level of selected materials, and the impacts to the environment were evaluated. In the case of flooding, dust, concrete and metal were found as a considerable object. In the case of fire event, dust, insulator and paint were the major concerns. As expected, the influence of normal fire and flooding at electron accelerator facilities would be relatively low for both cases.

  4. Labelling of macromoleculear carbohydrates by means of 'Hot Atom' reactions

    International Nuclear Information System (INIS)

    Lundqvist, H.; Malmborg, P.

    1976-01-01

    Radioactive labelling of polysaccharides have been performed using atoms with such high kinetic energy that they can break normally very stable bindings thus permitting labelling by substitution reactions. Such atoms can be produced in nuclear transformations. We have chosen to study the labelling efficiency of 'hot atoms' ( 77 Br, 123 I and 125 I) produced in radioactive decay (β + -decay and E.C.) of noble gas nuclides ( 77 Kr, 123 Xe and 125 Xe) which easily could be brought in close contact with the molecule to be labelled. Substances to be labelled have been starch particles and high molecular weight glycogen. (author)

  5. Coupling effect between film boiling heat transfer and evaporation drag around a hot-particle in cold liquid

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-Yan; YANG Yan-Hua; XU Ji-Jun

    2003-01-01

    Extremely rapid evaporation could occur when high-temperature particles contact withlow-temperature liquid. This kind of phenomenon is associated with the engineering safety and the problems inhigh-transient multi-phase fluid and heat transfer. The aim of our study was to design and build an observable ex-periment facility. The first series of experiments were performed by pouring one or six high-temperature particles intoa low saturated temperature liquid pool. The particle's falling-down speed was recorded by a high-speed camera, thuswe can find the special resistant feature of the moving high-temperature particles, which is induced by the high-speedevaporation surrounding the particles. The study has experimentally verified the theory of evaporation drag model.

  6. Study of the radioactive particle tracking technique using gamma-ray attenuation and MCNP-X code to evaluate industrial agitators

    Energy Technology Data Exchange (ETDEWEB)

    Dam, Roos Sophia de F.; Salgado, César M., E-mail: rsophia.dam@gmail.com, E-mail: otero@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    Agitators or mixers are highly used in the chemical, food, pharmaceutical and cosmetic industries. During the fabrication process, the equipment may fail and compromise the appropriate stirring or mixing procedure. Besides that, it is also important to determine the right point of homogeneity of the mixture. Thus, it is very important to have a diagnosis tool for these industrial units to assure the quality of the product and to keep the market competitiveness. The radioactive particle tracking (RPT) technique is widely used in the nuclear field. In this paper, a method based on the principles of the RPT technique is presented. Counts obtained by an array of detectors properly positioned around the unit will be correlated to predict the instantaneous positions occupied by the radioactive particle by means of an appropriate mathematical search location algorithm. Detection geometry developed employs eight NaI(Tl) scintillator detectors and a Cs-137 (662 keV) source with isotropic emission of gamma-rays. The modeling of the detection system is performed using the Monte Carlo Method, by means of the MCNP-X code. In this work a methodology is presented to predict the position of a radioactive particle to evaluate the performance of agitators in industrial units by means of an Artificial Neural Network (ANN). (author)

  7. Contamination of foods by radioactive rains

    Energy Technology Data Exchange (ETDEWEB)

    Obo, F; Wakamatsu, C; Nakae, Y; Higasayama, S

    1955-01-01

    The radioactivities of various vegetable foods contaminated by radioactive rains in May, 1954, in the Kagoshima Area were detected. Tea showed especially high radioactivities which could be extracted with hot water. Radioactive Nb, Zr, Hf, Ce, Y, Pr, and La were detected in the hot water extractions of tea by ion-exchange chromatography. The partial contribution of /sup 40/K in these radioactive vegetables was critically examined.

  8. Detection and analysis of radioactive particles using autoradiography. Report on task FIN A845 on the Finnish support programme to IAEA safeguards

    International Nuclear Information System (INIS)

    Poellaenen, R.; Kansanaho, A.; Toivonen, H.

    1996-02-01

    Autoradiography was used to study radioactive particles that may be released from the nuclear fuel cycle. Autoradiography suits for pre-screening of the samples. Radioactive particles can be located accurately and detached from the sample for subsequent analyses. A digital scanner and tailored software allow to estimate the activity of the particles by a factor of two to three. High-energy beta emitters as well as pure beta emitters can be identified. A particle with activity of 0.1 Bq can be detected in five days of exposure. More than 10 5 disintegrations are needed to detect a black spot on the autoradiography film. Total activity of beta active nuclides can be evaluated if the number of disintegrations is smaller than 10 6 . The diameter of the black spot is then below 1 mm. The edge of the black spot receives a beta dose of approximately 10 mGy. Particular emphasis was placed on method development for the point of view of in-field applications. (orig.) (12 refs., 17 figs., 5 tabs.)

  9. Ensemble Monte Carlo particle investigation of hot electron induced source-drain burnout characteristics of GaAs field-effect transistors

    Science.gov (United States)

    Moglestue, C.; Buot, F. A.; Anderson, W. T.

    1995-08-01

    The lattice heating rate has been calculated for GaAs field-effect transistors of different source-drain channel design by means of the ensemble Monte Carlo particle model. Transport of carriers in the substrate and the presence of free surface charges are also included in our simulation. The actual heat generation was obtained by accounting for the energy exchanged with the lattice of the semiconductor during phonon scattering. It was found that the maximum heating rate takes place below the surface near the drain end of the gate. The results correlate well with a previous hydrodynamic energy transport estimate of the electronic energy density, but shifted slightly more towards the drain. These results further emphasize the adverse effects of hot electrons on the Ohmic contacts.

  10. Development of Duplex Stainless Steels by Field-Assisted Hot Pressing: Influence of the Particle Size and Morphology of the Powders on the Final Mechanical Properties

    Science.gov (United States)

    García-Junceda, A.; Rincón, M.; Torralba, J. M.

    2018-01-01

    The feasibility of processing duplex stainless steels with promising properties using a powder metallurgical route, including the consolidation by field-assisted hot pressing, is assessed in this investigation. The influence of the particle size and morphology of the raw austenitic and ferritic powders on the final microstructure and properties is also evaluated for an austenitic content of 60 wt pct. In addition, the properties of a new microconstituent generated between the initial constituents are analyzed. The maximum sintered density (98.9 pct) and the best mechanical behavior, in terms of elastic modulus, nanohardness, yield strength, ultimate tensile strength, and ductility, are reached by the duplex stainless steel processed with austenitic and ferritic gas atomized stainless steel powders.

  11. Understanding radioactive waste

    International Nuclear Information System (INIS)

    Murray, R.L.

    1989-01-01

    This book discusses the sources and health effects of radioactive wastes. It reveals the techniques to concentrate and immobilize radioactivity and examines the merits of various disposal ideas. The book, which is designed for the lay reader, explains the basic science of atoms,nuclear particles,radioactivity, radiation and health effects

  12. Hot Flashes

    Science.gov (United States)

    Hot flashes Overview Hot flashes are sudden feelings of warmth, which are usually most intense over the face, neck and chest. Your skin might redden, as if you're blushing. Hot flashes can also cause sweating, and if you ...

  13. HOT 2015

    DEFF Research Database (Denmark)

    Hannibal, Sara Stefansen

    2016-01-01

    HOT samler og formidler 21 literacykyndiges bud på, hvad der er hot, og hvad der bør være hot inden for literacy – og deres begrundelser for disse bud.......HOT samler og formidler 21 literacykyndiges bud på, hvad der er hot, og hvad der bør være hot inden for literacy – og deres begrundelser for disse bud....

  14. Composition and fate of mine- and smelter-derived particles in soils of humid subtropical and hot semi-arid areas

    Energy Technology Data Exchange (ETDEWEB)

    Ettler, Vojtěch, E-mail: ettler@natur.cuni.cz [Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University in Prague, Albertov 6, 128 43 Praha 2 (Czech Republic); Johan, Zdenek [BRGM, Avenue Claude Guillemin, 45082 Orléans Cedex 2 (France); Kříbek, Bohdan; Veselovský, František [Czech Geological Survey, Geologická 6, 152 00 Praha 5 (Czech Republic); Mihaljevič, Martin [Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University in Prague, Albertov 6, 128 43 Praha 2 (Czech Republic); Vaněk, Aleš; Penížek, Vít [Department of Soil Science and Soil Protection, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamýcká 129, 165 21 Praha 6 (Czech Republic); Majer, Vladimír [Czech Geological Survey, Geologická 6, 152 00 Praha 5 (Czech Republic); Sracek, Ondra [Department of Geology, Faculty of Science, Palacký University in Olomouc, 17. listopadu 12, 771 46 Olomouc (Czech Republic); Mapani, Ben; Kamona, Fred [Department of Geology, Faculty of Science, University of Namibia, Private Bag 13301, Windhoek (Namibia); Nyambe, Imasiku [University of Zambia, School of Mines, P. O. Box 32 379, Lusaka (Zambia)

    2016-09-01

    We studied the heavy mineral fraction, separated from mining- and smelter-affected topsoils, from both a humid subtropical area (Mufulira, Zambian Copperbelt) and a hot semi-arid area (Tsumeb, Namibia). High concentrations of metal(loid)s were detected in the studied soils: up to 1450 mg As kg{sup −1}, 8980 mg Cu kg{sup −1}, 4640 mg Pb kg{sup −1}, 2620 mg Zn kg{sup −1}. A combination of X-ray diffraction analysis (XRD), scanning electron microscopy (SEM/EDS), and electron probe microanalysis (EPMA) helped to identify the phases forming individual metal(loid)-bearing particles. Whereas spherical particles originate from the smelting and flue gas cleaning processes, angular particles have either geogenic origins or they are windblown from the mining operations and mine waste disposal sites. Sulphides from ores and mine tailings often exhibit weathering rims in contrast to smelter-derived high-temperature sulphides (chalcocite [Cu{sub 2}S], digenite [Cu{sub 9}S{sub 5}], covellite [CuS], non-stoichiometric quenched Cu–Fe–S phases). Soils from humid subtropical areas exhibit higher available concentrations of metal(loids), and higher frequencies of weathering features (especially for copper-bearing oxides such as delafossite [Cu{sup 1+} Fe{sup 3+} O{sub 2}]) are observed. In contrast, metal(loid)s are efficiently retained in semi-arid soils, where a high proportion of non-weathered smelter slag particles and low-solubility Ca–Cu–Pb arsenates occur. Our results indicate that compared to semi-arid areas (where inorganic contaminants were rather immobile in soils despite their high concentrations) a higher potential risk exists for agriculture in mine- and smelter-affected humid subtropical areas (where metal(loid) contaminants can be highly available for the uptake by crops). - Highlights: • Mining- and smelter-derived particles identified in subtropical and semi-arid soils • Sulphides, oxides, and metal-bearing arsenates most frequently encountered

  15. 'Hot particles' in the cold light of day: principles for a stakeholder and public engagement architecture relating to historic liabilities in the marine environment

    International Nuclear Information System (INIS)

    Wylie, Rick

    2007-01-01

    This paper discusses issues in stakeholder relations, focusing on the challenges of liabilities management associated with small fragments of irradiated nuclear fuel hereafter termed particles (and sometimes termed 'hot particles' in the public domain, from which this paper gets its title), produced over a number of decades from now ceased operations at Dounreay. It describes key problems confronting the nuclear industry in developing a stakeholder-relations strategy. Drawing upon examples of the stakeholder activity at Dounreay, and using an ecological metaphor, an innovative architecture for stakeholder engagement relating to nuclear issues is outlined. This is based upon the view that the solution of the stakeholder issue must reflect the complexity and connectivity of influences and interests within the stakeholder environment. It is argued that the lay public should be visualised as the stakeholder if an effective stakeholder-relations strategy is to be achieved. The importance of creating trust in a context of scientific uncertainty is highlighted. This will, it is argued, become an increasingly salient issue in the thrust for openness and transparency, two key drivers of nuclear industry public and stakeholder relations, which could make the limits of scientific knowledge and control more widely appreciated, and bring to the fore the role of lay conceptions of perceived risk

  16. 'Hot particles' in the cold light of day: principles for a stakeholder and public engagement architecture relating to historic liabilities in the marine environment.

    Science.gov (United States)

    Wylie, Rick

    2007-09-01

    This paper discusses issues in stakeholder relations, focusing on the challenges of liabilities management associated with small fragments of irradiated nuclear fuel hereafter termed particles (and sometimes termed 'hot particles' in the public domain, from which this paper gets its title), produced over a number of decades from now ceased operations at Dounreay. It describes key problems confronting the nuclear industry in developing a stakeholder-relations strategy. Drawing upon examples of the stakeholder activity at Dounreay, and using an ecological metaphor, an innovative architecture for stakeholder engagement relating to nuclear issues is outlined. This is based upon the view that the solution of the stakeholder issue must reflect the complexity and connectivity of influences and interests within the stakeholder environment. It is argued that the lay public should be visualised as the stakeholder if an effective stakeholder-relations strategy is to be achieved. The importance of creating trust in a context of scientific uncertainty is highlighted. This will, it is argued, become an increasingly salient issue in the thrust for openness and transparency, two key drivers of nuclear industry public and stakeholder relations, which could make the limits of scientific knowledge and control more widely appreciated, and bring to the fore the role of lay conceptions of perceived risk.

  17. Particle and power balances of hot-filament discharge plasmas in a multi-dipole device in the presence of a positively biased electrode

    International Nuclear Information System (INIS)

    Cho, M.H.; Hershkowitz, N.; Intrator, T.

    1989-01-01

    The plasma potential is typically assumed to float above an anode potential by a few times of an electron temperature (T /e). The difference between the plasma potential and the anode potential can be estimated by considering the particle production and loss. However, it has been reported experimentally that the plasma potential of a steady state plasma can be more negative than the anode potential with a potential dip (-- T /e) in front of the anode. This paper describes particle and power balances to estimate the bulk plasma potential of a hot-filament discharge plasma produced in a multi-dipole plasma device. The bulk plasma potential dependence on positive DC bias applied to an anode is analyzed, and the predicted characteristics of the plasma potential dependence are compared to the experiment. A steady state potential dip in front of an anode is experimentally observed using emissive probes with the zero emission inflection point method, and the conditions for the potential dip formation are derived

  18. Radioactivity measurement

    International Nuclear Information System (INIS)

    Bohme, R.F.; Lazerson, M.M.

    1984-01-01

    A problem with ore sorting arrangements is that radiation is difficult to measure accurately while particles are moving at speed past the detector. This is particulary so when dealing with ores such as gold ores which have weak emissions. A method of measuring radioactive emissions from moving radioactive material includes the steps of shielding the radiation detector(s) so that the angle of acceptance of the receptor surface is restricted, and further shielding the shielded portion of the detector with a second material which is less radiation emissive than the material of the first shield. This second shield is between the first shield and the detector

  19. Characterization and source term assessments of radioactive particles from Marshall Islands using non-destructive analytical techniques

    Science.gov (United States)

    Jernström, J.; Eriksson, M.; Simon, R.; Tamborini, G.; Bildstein, O.; Marquez, R. Carlos; Kehl, S. R.; Hamilton, T. F.; Ranebo, Y.; Betti, M.

    2006-08-01

    Six plutonium-containing particles stemming from Runit Island soil (Marshall Islands) were characterized by non-destructive analytical and microanalytical methods. Composition and elemental distribution in the particles were studied with synchrotron radiation based micro X-ray fluorescence spectrometry. Scanning electron microscope equipped with energy dispersive X-ray detector and with wavelength dispersive system as well as a secondary ion mass spectrometer were used to examine particle surfaces. Based on the elemental composition the particles were divided into two groups: particles with pure Pu matrix, and particles where the plutonium is included in Si/O-rich matrix being more heterogenously distributed. All of the particles were identified as nuclear fuel fragments of exploded weapon components. As containing plutonium with low 240Pu/ 239Pu atomic ratio, less than 0.065, which corresponds to weapons-grade plutonium or a detonation with low fission yield, the particles were identified to originate from the safety test and low-yield tests conducted in the history of Runit Island. The Si/O-rich particles contained traces of 137Cs ( 239 + 240 Pu/ 137Cs activity ratio higher than 2500), which indicated that a minor fission process occurred during the explosion. The average 241Am/ 239Pu atomic ratio in the six particles was 3.7 × 10 - 3 ± 0.2 × 10 - 3 (February 2006), which indicated that plutonium in the different particles had similar age.

  20. Characterization and source term assessments of radioactive particles from Marshall Islands using non-destructive analytical techniques

    Energy Technology Data Exchange (ETDEWEB)

    Jernstroem, J. [Laboratory of Radiochemistry, Department of Chemistry, P.O. Box 55, FI-00014 University of Helsinki (Finland)]. E-mail: jussi.jernstrom@helsinki.fi; Eriksson, M. [IAEA-MEL, International Atomic Energy Agency - Marine Environment Laboratory, 4 Quai Antoine 1er, MC 98000 Monaco (Monaco); Simon, R. [Institute for Synchrotron Radiation, Forschungszentrum Karlsruhe GmbH, D-76021 Karlsruhe (Germany); Tamborini, G. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe (Germany); Bildstein, O. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe (Germany); Marquez, R. Carlos [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe (Germany); Kehl, S.R. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551-0808 (United States); Hamilton, T.F. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551-0808 (United States); Ranebo, Y. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe (Germany); Betti, M. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe (Germany)]. E-mail: maria.betti@ec.europa.eu

    2006-08-15

    Six plutonium-containing particles stemming from Runit Island soil (Marshall Islands) were characterized by non-destructive analytical and microanalytical methods. Composition and elemental distribution in the particles were studied with synchrotron radiation based micro X-ray fluorescence spectrometry. Scanning electron microscope equipped with energy dispersive X-ray detector and with wavelength dispersive system as well as a secondary ion mass spectrometer were used to examine particle surfaces. Based on the elemental composition the particles were divided into two groups: particles with pure Pu matrix, and particles where the plutonium is included in Si/O-rich matrix being more heterogenously distributed. All of the particles were identified as nuclear fuel fragments of exploded weapon components. As containing plutonium with low {sup 240}Pu/{sup 239}Pu atomic ratio, less than 0.065, which corresponds to weapons-grade plutonium or a detonation with low fission yield, the particles were identified to originate from the safety test and low-yield tests conducted in the history of Runit Island. The Si/O-rich particles contained traces of {sup 137}Cs ({sup 239+240}Pu/{sup 137}Cs activity ratio higher than 2500), which indicated that a minor fission process occurred during the explosion. The average {sup 241}Am/{sup 239}Pu atomic ratio in the six particles was 3.7 x 10{sup -3} {+-} 0.2 x 10{sup -3} (February 2006), which indicated that plutonium in the different particles had similar age.

  1. Electron microscopy characterization of mechanically alloyed and hot consolidates Cu-Cr3C2 particles

    Directory of Open Access Journals (Sweden)

    López, M.

    2005-08-01

    Full Text Available Mechanically alloyed copper-ceramic composites have been obtained with the purpose of studying their use as copper-based material for electrical equipment. For high-temperature applications, dispersion-strengthened copper alloys are attractive due to their excellent combination of thermal and electrical conductivity, mechanical strength retention and microstructural stability. In this work, powder mixtures of pure copper with 2 vol % Cr3C2, milled during 4, 6, 10, 12 and 15 h in a high-energy planetary balls mill under argon atmosphere, were consolidated by hot isostatic pressing, applying a pressure of 100 MPa at 1073 K for two hours, to obtain materials with a fine microstructure. The Cu-Cr3C2 alloys were studied by scanning electron microscopy (SEM, electron microprobe (EPMA and transmission electron microscopy (TEM. Mechanical properties and electrical conductivity were also studied. The average tensile strength and electrical conductivity were found to be 500 MPa and 50 % IACS, respectively. The Cr3C2 ceramics show good stability during hot consolidation. Contributing to a further strengthening of the alloy during the hot consolidation, uniformly-distributed Fe-carbide particles of nanometric size precipitated in the copper matrix. Fe-Cr oxycarbides formed in the interphase between Cr3C2 particles and the copper matrix cause the low ductility of Cu-Cr3C2 alloys. Said particles are attributed to impurities/contamination generated from the milling process.

    Se obtuvieron aleaciones compuestas de Cu-Cr3C2, aleadas mecánicamente, para estudiar futuras aplicaciones en componentes eléctricos. A altas temperaturas, las aleaciones de base cobre reforzadas por dispersión, son atractivas por su excelente conductividad térmica y eléctrica, propiedades mecánicas y estabilidad microstructural. En este estudio

  2. IEN low-level radioactive waste management

    International Nuclear Information System (INIS)

    Rocha, A.C.S. da; Pina, J.L.S.; Silva, S. da; Silva, J.J.G.

    1986-09-01

    The low-level radioactive waste produced in Instituto de Engenharia Nuclear is generated basically from three distinct modes: a particle accelerator (CV-28 Cyclotron), radiochemistry laboratories and the operation of a nuclear research reactor (Argonaut type). In the Cyclotron unit, all water flow from hot labs as well as from the decontamination laundry is retained in special tank with homogenizing system and a remote control, that signalizes when the tank gets a pre-specified level. Samples homogenized from the tank are colected for previous analysis. (Author) [pt

  3. Passive Optimization Design Based on Particle Swarm Optimization in Rural Buildings of the Hot Summer and Warm Winter Zone of China

    Directory of Open Access Journals (Sweden)

    Shilei Lu

    2017-12-01

    Full Text Available The development of green building is an important way to solve the environmental problems of China’s construction industry. Energy conservation and energy utilization are important for the green building evaluation criteria (GBEC. The objective of this study is to evaluate the quantitative relationship between building shape parameter, envelope parameters, shading system, courtyard and the energy consumption (EC as well as the impact on indoor thermal comfort of rural residential buildings in the hot summer and warm winter zone (HWWZ. Taking Quanzhou (Fujian Province of China as an example, based on the field investigation, EnergyPlus is used to build the building performance model. In addition, the classical particle swarm optimization algorithm in GenOpt software is used to optimize the various factors affecting the EC. Single-objective optimization has provided guidance to the multi-dimensional optimization and regression analysis is used to find the effects of a single input variable on an output variable. Results shows that the energy saving rate of an optimized rural residence is about 26–30% corresponding to the existing rural residence. Moreover, the payback period is about 20 years. A simple case study is used to demonstrate the accuracy of the proposed optimization analysis. The optimization can be used to guide the design of new rural construction in the area and the energy saving transformation of the existing rural houses, which can help to achieve the purpose of energy saving and comfort.

  4. Comparative study of two drying techniques used in radioactive source preparation: Freeze-drying and evaporation using hot dry nitrogen jets

    International Nuclear Information System (INIS)

    Branger, T.; Bobin, C.; Iroulart, M.-G.; Lepy, M.-C.; Le Garreres, I.; Morelli, S.; Lacour, D.; Plagnard, J.

    2008-01-01

    Quantitative solid sources are used widely in the field of radionuclide metrology. With the aim to improve the detection efficiency for electrons and x-rays, a comparative study between two source drying techniques has been undertaken at LNE-Laboratoire National Henri Becquerel (LNE-LNHB, France). In this paper, freeze-drying using commercial equipment is compared with a system of drying using hot jets of nitrogen developed at Institute for Reference Materials and Measurements (IRMM, Belgium). In order to characterize the influence of self-absorption, the detection efficiencies for 51 Cr sources have been measured by coincidence counting and photon spectrometry

  5. Particle-accelerator decommissioning

    International Nuclear Information System (INIS)

    Opelka, J.H.; Mundis, R.L.; Marmer, G.J.; Peterson, J.M.; Siskind, B.; Kikta, M.J.

    1979-12-01

    Generic considerations involved in decommissioning particle accelerators are examined. There are presently several hundred accelerators operating in the United States that can produce material containing nonnegligible residual radioactivity. Residual radioactivity after final shutdown is generally short-lived induced activity and is localized in hot spots around the beam line. The decommissioning options addressed are mothballing, entombment, dismantlement with interim storage, and dismantlement with disposal. The recycle of components or entire accelerators following dismantlement is a definite possibility and has occurred in the past. Accelerator components can be recycled either immediately at accelerator shutdown or following a period of storage, depending on the nature of induced activation. Considerations of cost, radioactive waste, and radiological health are presented for four prototypic accelerators. Prototypes considered range from small accelerators having minimal amounts of radioactive mmaterial to a very large accelerator having massive components containing nonnegligible amounts of induced activation. Archival information on past decommissionings is presented, and recommendations concerning regulations and accelerator design that will aid in the decommissioning of an accelerator are given

  6. Construction of concrete hot cells

    International Nuclear Information System (INIS)

    1981-12-01

    The standard is to be applied to rooms (hot cells) which are enclosed by a concrete shield and in which radioactive material is handled by remote control. The rooms may be in facilities for experimental purposes (e.g. development of fuel elements and materials or of chemical processes) or in facilities for production purposes (e.g. reprocessing of nuclear fuel or treatment of radioactive wastes). The standard is to give a design hasis for concrete hot cells and their installations which is to be applied by designers, constructors, future users and competent authorities as well as independent experts. (orig.) [de

  7. Construction of concrete hot cells

    International Nuclear Information System (INIS)

    1980-09-01

    The standard is to be applied to rooms (hot cells) which are enclosed by a concrete shield and in which radioactive material is handled by remote control. The rooms may be in facilities for experimental purposes (e.g. development of fuel elements and materials or of chemical processes) or in facilities for production purposes (e.g. reprocessing of nuclear fuel or treatment of radioactive wastes). The standard is to give a design basis for concrete hot cells and their installations which is to be applied by designers, constructors, future users and competent authorities as well as independent experts. (orig.) [de

  8. Alpha-particle autoradiography by solid state track detectors to spatial distribution of radioactivity in alpha-counting source

    International Nuclear Information System (INIS)

    Ishigure, Nobuhito; Nakano, Takashi; Enomoto, Hiroko; Koizumi, Akira; Miyamoto, Katsuhiro

    1989-01-01

    A technique of autoradiography using solid state track detectors is described by which spatial distribution of radioactivity in an alpha-counting source can easily be visualized. As solid state track detectors, polymer of allyl diglycol carbonate was used. The advantage of the present technique was proved that alpha-emitters can be handled in the light place alone through the whole course of autoradiography, otherwise in the conventional autoradiography the alpha-emitters, which requires special carefulness from the point of radiation protection, must be handled in the dark place with difficulty. This technique was applied to rough examination of self-absorption of the plutonium source prepared by the following different methods; the source (A) was prepared by drying at room temperature, (B) by drying under an infrared lamp, (C) by drying in ammonia atmosphere after redissolving by the addition of a drop of distilled water which followed complete evaporation under an infrared lamp and (D) by drying under an infrared lamp after adding a drop of diluted neutral detergent. The difference in the spatial distributions of radioactivity could clearly be observed on the autoradiographs. For example, the source (C) showed the most diffuse distribution, which suggested that the self-absorption of this source was the smallest. The present autoradiographic observation was in accordance with the result of the alpha-spectrometry with a silicon surface-barrier detector. (author)

  9. Study on treatment of radioactive liquid waste from uranium ore processing by the use of nano Fe_3O_4 KT particles

    International Nuclear Information System (INIS)

    Vuong Huu Anh; Nguyen Ba Tien; Doan Thi Thu Hien; Luu Cao Nguyen; Nguyen Van Chinh

    2015-01-01

    Nano Fe_3O_4 KT was produced from the Military Institute of Science and Technology were used to adsorbed heavy metal elements in liquid waste. In this report, the nano Fe_3O_4 KT particles sized 80-100 nm and specific surface area was 50-70 m"2/g was applied to study the adsorption of radioactive elements in the liquid waste of uranium ores processing. The effective parameters on adsorption process included temperature, stirring rate, stirring time, the pH value of the solution, the initial concentration of uranium in solution. The results showed the maximum adsorption capacity of the nano Fe_3O_4 KT was 53.5 mg/g with conditions such as room temperature, stirring speed 120 rounds/minute, the pH value of solution was 8, stirring time about 2 hours (Uranium/materials). From the results obtained, nano Fe_3O_4 KT tested to treatment liquid waste of uranium ore processing after preliminary precipitation removed almost heavy metals and a part of radioactive elements. The results were analyzed on the ICP-MS and α, β total counting, instrument. The solution concentration after treatment was suitable for Vietnam discharge standards into environment (QCVN 40:2011 on Industrial wastewater). (author)

  10. Low-level radioactive river sediment particles originating from the Chalk river nuclear site carry a mixture of radionuclides and metals

    Energy Technology Data Exchange (ETDEWEB)

    Lind, Ole Christian; Cagno, Simone; Salbu, Brit [Norwegian University of Life Sciences - NMBU, Center of Excellence in Environmental Radioactivity - CERAD, P.O. Box 5003, N-1432 Aas (Norway); Falkenberg, Gerald [Photon science, DESY, Hamburg (Germany); Janssens, Koen; Nuyts, Gert; Vanmeert, Frederik [AXIL, Department of Chemistry, University of Antwerpen (Belgium); Jaroszewicz, Jakub [Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw (Poland); Priest, Nicholas D.; Audet, Marc [Nuclear Science Division, AECL Chalk River Laboratories (Canada)

    2014-07-01

    The Chalk River Laboratory of Atomic Energy of Canada Ltd., site is located on the Ottawa River approximately 200 km northwest of Ottawa, Canada. The site has two large research reactors: NRX, which operated from 1947 to 1991 and NRU, which continues to operate and is used to produce a significant fraction of the world's supply of medical isotopes. During the course of the operation of the NRX reactor small quantities of radioactive particles were discharged to the Ottawa River through a process sewer discharge pipe. These are now located in river bed sediments within a 0.08 km² area close to the discharge pipe. In the present study, selected particles were isolated from riverbed sediments. These were then characterized by environmental scanning electron microscopy with energy dispersive micro X-ray analysis (ESEM-EDX). This was undertaken to obtain information on particle size, structure and the distribution of elements across particle surfaces. Based on the results of ESEM-EDX, particles were selected for X-ray absorption nano-tomography analysis, which provides videos showing the 3D density distribution of the particles. Furthermore, 2D and 3D Synchrotron Radiation based X-ray techniques (micro-X-ray fluorescence; micro-XRF, micro-X-ray absorption near edge spectroscopy; micro-XANES and micro-X-ray diffraction; micro-XRD) with submicron resolution (beam size 0.5 μm) were employed to investigate the elemental and phase composition (micro-XRF/XRD) and oxidation states (micro-XANES) of matrix elements with high spatial resolution and sensitivity. Results show that the particles investigated so far varied according to: 1) <~40 μm diameter sized U fuel particles similar in structure to particles observed from Chernobyl and Krasnoyarsk-26 and 2) larger particles with diameters up to several hundred μm. The larger particles comprised a matrix of low density, sediment material with high density inclusions that contained a range of metals including Cu, Cr, As

  11. Ninth international symposium on hot atom chemistry. Abstracts

    International Nuclear Information System (INIS)

    1977-01-01

    Abstracts of the papers presented at the Symposium are compiled. The topics considered were chemical dynamics of high energy reactions, hot atom chemistry in organic compounds of tritium, nitrogen, oxygen, and halogens, theory and chemical dynamics of hot atom reactions as determined by beam studies, solid state reactions of recoil atoms and implanted ions, hot atom chemistry in energy-related research, hot atom chemistry in inorganic compounds of oxygen and tritium, hot positronium chemistry, applied hot atom chemistry in labelling, chemical effects of radioactive decay, decay-induced reactions and excitation labelling, physical methods in hot atom chemistry, and hot atom reactions in radiation and stratospheric chemistry

  12. HOT 2012

    DEFF Research Database (Denmark)

    Lund, Henriette Romme

    Undersøgelse af, hvad der er hot - og hvad der burde være hot på læseområdet med 21 læsekyndige. Undersøgelsen er gennemført siden 2010. HOT-undersøgelsen er foretaget af Nationalt Videncenter for Læsning - Professionshøjskolerne i samarb. med Dansklærerforeningen......Undersøgelse af, hvad der er hot - og hvad der burde være hot på læseområdet med 21 læsekyndige. Undersøgelsen er gennemført siden 2010. HOT-undersøgelsen er foretaget af Nationalt Videncenter for Læsning - Professionshøjskolerne i samarb. med Dansklærerforeningen...

  13. HOT 2014

    DEFF Research Database (Denmark)

    Lund, Henriette

    Undersøgelse af, hvad der er hot - og hvad der burde være hot på læseområdet med 21 læsekyndige. Undersøgelsen er gennemført siden 2010. HOT-undersøgelsen er foretaget af Nationalt Videncenter for Læsning - Professionshøjskolerne i samarb. med Dansklærerforeningen...

  14. HOT 2011

    DEFF Research Database (Denmark)

    Lund, Henriette Romme

    En undersøgelse af, hvad der er hot - og burde være hot på læseområdet. I undersøgelsen deltager 21 læsekyndige fra praksisfeltet, professionshøjskolerne og forskningsområdet.......En undersøgelse af, hvad der er hot - og burde være hot på læseområdet. I undersøgelsen deltager 21 læsekyndige fra praksisfeltet, professionshøjskolerne og forskningsområdet....

  15. Chernobyl hot particles in the lungs of personnel involved in the post-accident clean-up actions and of inhabitants of the contaminated Ukrainian and Belarus territories

    International Nuclear Information System (INIS)

    Vlasov, P.A.; Shevchenko, A.A.; Shashlov, S.V.; Kvacheva, Yu.E.; Pogodin, R.I.; Skryabin, A.M.; Kutkov, V.A.

    1997-01-01

    The investigation of the body content by direct or indirect methods permits to determine the amount of the radioactivity inhaled and the relevant averaged over an organ committed dose. According to traditional dosimetry approach that is enough or rough prediction of committed detriment. For the real prognosis of the hazard due to aerosol inhalation in accordance with the alternative radiobiological model, it is necessary to know the microdistribution of deposited radioactive material as well as the relevant microdistribution of the deposited energy in target microstructures of the lungs. The only technique for investigating the microdistribution of a radioactivity is the histoautoradiographic examination of autopsy material

  16. Experimental study of radioactive aerosols in the vicinity of the Chernobyl Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Boulyga, S.F.; Lomonosova, E.M.; Zhuk, I.V.; Yaroshevich, O.I.; Kudrjashov, V.P.; Mironov, V.P

    1999-12-01

    Study of radioactive aerosols in the relocation zone and in the populated areas have been carried out for a number of years. The experiments on modelling resuspension were performed while conducting agricultural work. Nuclear track radiography and alpha spectrometry with radiochemical extraction of plutonium were used as analytical methods for the determination of the transuranium elements contents. The distributions of radioactive particles were obtained as to activity and sizes. Specific activity of 'hot particles' increases with decreasing diameter. In aerosols selected at a distance of more than 10 km from the Chernobyl NPP pure fuel particles with sizes of more than 5 {mu}m were not found. The activity of the finely dispersed fraction of aerosols, which is more dangerous when inhaled by the organism, is comparable with a total activity of large particles.

  17. Experimental study of radioactive aerosols in the vicinity of the Chernobyl Nuclear Power Plant

    International Nuclear Information System (INIS)

    Boulyga, S.F.; Lomonosova, E.M.; Zhuk, I.V.; Yaroshevich, O.I.; Kudrjashov, V.P.; Mironov, V.P.

    1999-01-01

    Study of radioactive aerosols in the relocation zone and in the populated areas have been carried out for a number of years. The experiments on modelling resuspension were performed while conducting agricultural work. Nuclear track radiography and alpha spectrometry with radiochemical extraction of plutonium were used as analytical methods for the determination of the transuranium elements contents. The distributions of radioactive particles were obtained as to activity and sizes. Specific activity of 'hot particles' increases with decreasing diameter. In aerosols selected at a distance of more than 10 km from the Chernobyl NPP pure fuel particles with sizes of more than 5 μm were not found. The activity of the finely dispersed fraction of aerosols, which is more dangerous when inhaled by the organism, is comparable with a total activity of large particles

  18. Waste treatment process by solidifying cementitious materials using hydrothermal hot-pressing

    International Nuclear Information System (INIS)

    Matsumoto, Y.; Kamakura, T.; Yamasaki, N.; Hashida, T.

    2001-01-01

    Solidification of low-level radioactive wastes containing Na 2 SO 4 with cement by hydrothermal hot-pressing (HHP) technique was examined. Relatively high mechanical strength, reduced leaching ratio of SO 3 , and higher resistance to the carbonation of the HHP product were attained in comparison with conventional concrete. The solidification by the HHP treatment may be proceeded by the rearrangement of particles and the bonding material formation among the particles by dissolution-deposition process. The possibility of developing the accelerated testing method for duration of cemented materials by hydrothermal method was discussed. (author)

  19. Process and equipment development for hot isostatic pressing treatability study

    Energy Technology Data Exchange (ETDEWEB)

    Bateman, Ken; Wahlquist, Dennis; Malewitz, Tim

    2015-03-01

    Battelle Energy Alliance (BEA), LLC, has developed processes and equipment for a pilot-scale hot isostatic pressing (HIP) treatability study to stabilize and volume reduce radioactive calcine stored at Idaho National Laboratory (INL). In 2009, the U. S. Department of Energy signed a Record of Decision with the state of Idaho selecting HIP technology as the method to treat 5,800 yd^3 (4,400 m^3) of granular zirconia and alumina calcine produced between 1953 and 1992 as a waste byproduct of spent nuclear fuel reprocessing. Since the 1990s, a variety of radioactive and hazardous waste forms have been remotely treated using HIP within INL hot cells. To execute the remote process at INL, waste is loaded into a stainless-steel or aluminum can, which is evacuated, sealed, and placed into a HIP furnace. The HIP simultaneously heats and pressurizes the waste, reducing its volume and increasing its durability. Two 1 gal cans of calcine waste currently stored in a shielded cask were identified as candidate materials for a treatability study involving the HIP process. Equipment and materials for cask-handling and calcine transfer into INL hot cells, as well as remotely operated equipment for waste can opening, particle sizing, material blending, and HIP can loading have been designed and successfully tested. These results demonstrate BEA’s readiness for treatment of INL calcine.

  20. Atmospheric natural radioactivity outdoors

    International Nuclear Information System (INIS)

    Renoux, A.

    1985-01-01

    Following a short account of natural atmospheric radioactivity, radon concentrations are given as well as their variations with time obtained by means of a original apparatus developped in Brest. The radioactive equilibrium of radon and its daughters is then considered, many experiments demonstrating that equilibrium is seldom reached even for 218 Po (RaA). Finally, some characteristics of natural radioactive aerosols are studied: charge, particle size distribution (demonstrating they are fine aerosols since only 30 per cent are made of particles with radii exceeding 0,1 μm) [fr

  1. Radioactive wastes

    International Nuclear Information System (INIS)

    Straub, C.P.

    1975-01-01

    A review is presented on the environmental behavior of radioactive wastes. The management of high-level wastes and waste disposal methods were discussed. Some topics included were ore processing, coagulation, absorption and ion exchange, fixation, ground disposal, flotation, evaporation, transmutation and extraterrestrial disposal. Reports were given of the 226 Ra, 224 Ra and tritium activity in hot springs, 90 Sr concentrations in the groundwater and in White Oak Creek, radionuclide content of algae, grasses and plankton, radionuclides in the Danube River, Hudson River, Pacific Ocean, Atlantic Ocean, Lake Michigan, Columbia River and other surface waters. Analysis showed that 239 Pu was scavenged from Lake Michigan water by phytoplankton and algae by a concentration factor of up to 10,000. Benthic invertebrates and fish showed higher 239 Pu concentrations than did their pelagic counterparts. Concentration factors are also given for 234 Th, 60 Co, Fe and Mr in marine organisms. Two models for predicting the impact of radioactivity in the food chain on man were mentioned. In an accidental release from a light-water power reactor to the ocean, the most important radionuclides discharged were found to be 90 Sr, 137 Cs, 239 Pu and activation products 65 Zr, 59 Fe, and 95 Zr

  2. Radiation exposure and risk estimates for inhaled airborne radioactive pollutants including hot particles. Annual report 1 July 1976--30 June 1977

    International Nuclear Information System (INIS)

    Mewhinney, J.A.

    1978-03-01

    Contents: Mixed-oxide fuel fabrication; Generation of aerosols of mixed uranium-plutonium oxides from dry powders for animal inhalation exposures; Analytical radiochemical determination of U, Pu and Am in biological samples; Physical chemical characterization of mixed uranium-plutonium oxide nuclear fuel as samples during animal inhalation exposure; Pilot studies of deposition and retention of industrial mixed-oxide aerosols in the laboratory rat; Extended radiation dose pattern studies of aerosols of mixed uranium-plutonium oxides treated at 750C inhaled by Fishcer-344 rats, beagle dogs and cynomolgus monkeys; Extended radiation dose pattern studies of aerosols of plutonium dioxide, treated at 850C and inhaled by Fischer-344 rats, beagle dogs and cynomolgus monkeys

  3. [Effect of image fusion technology of radioactive particles implantation before and after the planning target and dosimetry].

    Science.gov (United States)

    Jiang, Y L; Yu, J P; Sun, H T; Guo, F X; Ji, Z; Fan, J H; Zhang, L J; Li, X; Wang, J J

    2017-08-01

    Objective: To compare the post-implant target volumes and dosimetric evaluation with pre-plan, the gross tumor volume(GTV) by CT image fusion-based and the manual delineation of target volume in CT guided radioactive seeds implantation. Methods: A total of 10 patients treated under CT-guidance (125)I seed implantation during March 2016 to April 2016 were analyzed in Peking University Third Hospital.All patients underwent pre-operative CT simulation, pre-operative planning, implantation seeds, CT scanning after seed implantation and dosimetric evaluation of GTV.In every patient, post-implant target volumes were delineated by both two methods, and were divided into two groups. Group 1: image fusion pre-implantation simulation and post-operative CT image, then the contours of GTV were automatically performed by brachytherapy treatment planning system; Group 2: the contouring of the GTV on post-operative CT image were performed manually by three senior radiation oncologists independently. The average of three data was sets. Statistical analyses were performed using SPSS software, version 3.2.0. The paired t -test was used to compare the target volumes and D(90) parameters in two modality. Results: In Group 1, average volume of GTV in post-operation group was 12-167(73±56) cm(3). D(90) was 101-153 (142±19)Gy. In Group 2, they were 14-186(80±58)cm(3) and 96-146(122±16) Gy respectively. In both target volumes and D(90), there was no statistical difference between pre-operation and post-operation in Group 1.The D(90) was slightly lower than that of pre-plan group, but there was no statistical difference ( P =0.142); in Group 2, between pre-operation and post-operation group, there was a significant statistical difference in the GTV ( P =0.002). The difference of D(90) was similarly ( P manual delineation of target volume by maximum reduce the interference from artificial factor and metal artifacts. Further work and more cases are required in the future.

  4. Development and evaluation of hot filters

    International Nuclear Information System (INIS)

    Thexton, H.E.

    1975-01-01

    High temperature, high flow filtration removes radioactive particles from the primary coolant, as well as inactive particles before they can become activated. Canadian experience with edge, graphite, and magnetic filters is described. (Author)

  5. Mechanical shielded hot cell

    International Nuclear Information System (INIS)

    Higgy, H.R.; Abdel-Rassoul, A.A.

    1983-01-01

    A plan to erect a mechanical shielded hot cell in the process hall of the Radiochemical Laboratory at Inchas is described. The hot cell is designed for safe handling of spent fuel bundles, from the Inchas reactor, and for dismantling and cutting the fuel rods in preparation for subsequent treatment. The biological shielding allows for the safe handling of a total radioactivity level up to 10,000 MeV-Ci. The hot cell consists of an α-tight stainless-steel box, connected to a γ-shielded SAS, through an air-lock containing a movable carriage. The α-box is tightly connected with six dry-storage cavities for adequate storage of the spent fuel bundles. Both the α-box, with the dry-storage cavities, and the SAS are surrounded by 200-mm thick biological lead shielding. The α-box is equipped with two master-slave manipulators, a lead-glass window, a monorail crane and Padirac and Minirag systems. The SAS is equipped with a lead-glass window, tong manipulator, a shielded pit and a mechanism for the entry of the spent fuel bundle. The hot cell is served by adequate ventilation and monitoring systems. (author)

  6. Radioactive apparatus for measuring the thickness of hot sheet-metal; Jauge d'epaisseur radioactive pour la mesure a chaud de plaques metalliques; Radioaktivnyj izmeritel' tolshchiny goryachego listovogo prokata; Calibrador radiactivo para la medicion en caliente de chapas

    Energy Technology Data Exchange (ETDEWEB)

    Vasichev, B N; Latyshev, V K; Pliskin, Yu S; Felinger, A K

    1962-01-15

    In order to achieve a high precision of measurement under rolling conditions, a dynamic method of compensation was chosen, by which the comparison parameter moves through all the values in the range of measurement, whereas the zero component designates only the moment when the measured parameter and the comparison parameter are equal. This method eliminates the mechanical return communications and variable displacements of the static-compensation method, and gives an instrument which is both sufficiently accurate and operates with sufficient speed in the complicated process of rolling. The basic design of the instrument, for checking the thickness of the sheet during the rolling process is described and the factors affecting the accuracy of measurement of a sheet (temperature, undulation, superficial moisture, composition of the sheet, and its position on the roller train) are discussed. The construction of an experimental instrument for industrial use over a thickness range of 14-44 mm is also described. The industrial tests carried out with the instrument showed that, with a Cs{sup 137} source of activity equivalent to 9.2 g radium, the accuracy of measurement of the thickness of hot sheet within the specified range is {+-}0.1 mm. The instrument's operating speed is one measurement per second. It works reliably under the conditions of the rolling mill. (author) [French] Pour obtenir une grande precision dans les mesures en cours de laminage, les auteurs ont choisi la methode dynamique de compensation, dans laquelle le parametre de comparaison passe par toutes les valeurs de la gamme de mesures, la composante zero designant uniquement le moment ou le parametre mesure et le parametre de comparaison sont egaux. Cette methode permet d'eliminer les systemes mecaniques de retour et les deplacements variables qui caracterisent la methode statique de compensation, et d'avoir un appareil a la fois suffisamment precis et d'un fonctionnement suffisamment rapide. Les auteurs

  7. HOT 2010

    DEFF Research Database (Denmark)

    Lund, Henriette Romme

    En undersøgelse af, hvad der er hot - og burde være hot på læseområdet. I undersøgelsen deltager en række læsekyndige fra praksisfeltet, professionshøjskolerne og forskningsområdet. Undersøgelsen er gentaget hvert år siden 2010.......En undersøgelse af, hvad der er hot - og burde være hot på læseområdet. I undersøgelsen deltager en række læsekyndige fra praksisfeltet, professionshøjskolerne og forskningsområdet. Undersøgelsen er gentaget hvert år siden 2010....

  8. HOT 2013

    DEFF Research Database (Denmark)

    Lund, Henriette Romme

    En undersøgelse af, hvad der er hot - og burde være hot på læseområdet. I undersøgelsen deltager en række læsekyndige fra praksisfeltet, professionshøjskolerne og forskningsområdet. Undersøgelsen er gentaget hvert år siden 2010.......En undersøgelse af, hvad der er hot - og burde være hot på læseområdet. I undersøgelsen deltager en række læsekyndige fra praksisfeltet, professionshøjskolerne og forskningsområdet. Undersøgelsen er gentaget hvert år siden 2010....

  9. Radioactive colloids

    International Nuclear Information System (INIS)

    Bergqvist, L.

    1987-01-01

    Different techniques for the characterization of radioactive colloids, used in nuclear medicine, have been evaluated and compared. Several radioactive colloids have been characterized in vitro and in vivo and tested experimentally. Colloid biokinetics following interstitial or intravenous injection were evaluated with a scintillation camera technique. Lymphoscintigraphy with a Tc-99-labelled antimony sulphur colloid was performed in 32 patients with malignant melanoma in order to evaluate the technique. Based on the biokinetic results, absorbed doses in tissues and organs were calculated. The function of the reticuloendothelial system has been evaluated in rats after inoculation with tumour cells. Microfiltration and photon correlation spectroscopy were found to be suitable in determining activity-size and particle size distributions, respectively. Maximal lymph node uptake following subcutaneous injection was found to correspond to a colloid particle size between 10 and 50 nm. Lymphoscintigraphy was found to be useful in the study of lymphatic drainage from the primary tumour site in patients with malignant melanoma on the trunk. Quantitative analysis of ilio-inguinal lymph node uptake in patients with malignant melanoma on the lower extremities was, however, found to be of no value for the detection of metastatic disease in lymph nodes. High absorbed doses may be received in lymph nodes (up to 1 mGy/MBq) and at the injection site (about 10 mGy/MBq). In an experimental study it was found that the relative colloid uptake in bone marrow and spleen depended on the total number of intravenously injected particles. This may considerably affect the absorbed dose in these organs. (author)

  10. Characterization study of cesium concentrated particles in the soils near the Fukushima Daiichi nuclear power plant

    Science.gov (United States)

    Satou, Yukihiko; Sueki, Keisuke; Sasa, Kimikazu; Adachi, Kouji; Igarashi, Yasuhito

    2015-04-01

    Radionuclides from the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident contaminated a vast area. Two types of contamination, spread and spot types, were observed in soils with autoradiography using an imaging plate. Other samples such as dust filters, vegetation, X-ray films, and so on, also indicate the spot type contamination in the early stage of the FDNPP accident. The source of spot type contamination is well known as hot particles at the Chernobyl Nuclear Power Plant (ChNPP) accident in 1986. Hot particles were divided into two groups, fuel hot particles and fission product particles, and they were emitted directly from reactor core with phreatic explosion and fire. In contrast, the official reports of the FDNPP accident did not conforme core explosion. In addition, the emitted total amount of Uranium was very few (Yamamoto et al., 2014). Thus, the spot type contaminations were not identified as the same of hot particles yet. Therefore, the present study aimed to pick up and identify the spot contaminations in soils. Surface soil samples were collected at 20 km northwest from the FDNPP in June 2013. Soils were spread in plastic bags for autoradiography with imaging plate analysis. Then, the soil particles were collected on a sticky carbon tape and analyzed by SEM-EDS to detect radioactive particles. Finally, particles were confirmed to contain photo peaks in the γ-spectrum by a germanium semiconductor detector. Four radioactive particles were isolated from the soil samples in the present study. Detected γ-ray emission radionuclides were only Cs-134 and Cs-137. The X-ray spectra on the SEM-EDS of all particles showed a Cs peak as well as O, Fe, Zn, and Rb peaks, and these elements were distributed uniformly within the particles. In addition, uniform distribution of Si was also shown. Moreover, U was detected from one of the particles, but U concentration was very low and existed locally in the particle. These characters are very similar to previous

  11. Improving the API dissolution rate during pharmaceutical hot-melt extrusion I: Effect of the API particle size, and the co-rotating, twin-screw extruder screw configuration on the API dissolution rate.

    Science.gov (United States)

    Li, Meng; Gogos, Costas G; Ioannidis, Nicolas

    2015-01-15

    The dissolution rate of the active pharmaceutical ingredients in pharmaceutical hot-melt extrusion is the most critical elementary step during the extrusion of amorphous solid solutions - total dissolution has to be achieved within the short residence time in the extruder. Dissolution and dissolution rates are affected by process, material and equipment variables. In this work, we examine the effect of one of the material variables and one of the equipment variables, namely, the API particle size and extruder screw configuration on the API dissolution rate, in a co-rotating, twin-screw extruder. By rapidly removing the extruder screws from the barrel after achieving a steady state, we collected samples along the length of the extruder screws that were characterized by polarized optical microscopy (POM) and differential scanning calorimetry (DSC) to determine the amount of undissolved API. Analyses of samples indicate that reduction of particle size of the API and appropriate selection of screw design can markedly improve the dissolution rate of the API during extrusion. In addition, angle of repose measurements and light microscopy images show that the reduction of particle size of the API can improve the flowability of the physical mixture feed and the adhesiveness between its components, respectively, through dry coating of the polymer particles by the API particles. Copyright © 2014. Published by Elsevier B.V.

  12. Radioactive Decay

    Science.gov (United States)

    Radioactive decay is the emission of energy in the form of ionizing radiation. Example decay chains illustrate how radioactive atoms can go through many transformations as they become stable and no longer radioactive.

  13. Non-radioactive stand-in for radioactive contamination. I. Non-radioactive tests

    International Nuclear Information System (INIS)

    Rohe, M.J.; Rankin, W.N.; Postles, R.L.

    1985-01-01

    Candidate non-radioactive materials for use as a stand-in for radioactive contamination during application of a high-pressure, hot water decontamination were identified and evaluated. A stand-in for radioactive contamination is needed to evaluate the decontaminability of replacement canyon cranes at the manufacturers location where actual radioactive contamination cannot be used. This evaluation was conducted using high-pressure, hot-water at 420 psi, 190 0 F, and 20 gal/min through a 1/8-in.-diam nozzle, the decontamination technique preferred by SRP Separations Department for this application. A non-radioactive stand-in for radioactive contamination was desired that would be removed by direct blast stream contact but would remain intact on surfaces where direct contact does not occur. This memorandum describes identification of candidate non-radioactive stand-in materials and evaluation of these materials in screening tests and tests with high-pressure, hot-water blasting. The following non-radioactive materials were tested: carpenter's line chalk; typing correction fluid; dye penetrant developer; latex paint with attapulyite added; unaltered latex paint; gold enamel; layout fluid; and black enamel. Results show that blue layout fluid and gold enamel have similar adherence that is within the range expected for actual radioactive contamination. White latex paint has less adherence than expected for actual radioactive contamination. The film was removed at a rate of 2 . Black enamel has more adherence than expected from actual radioactive contamination. In these tests ASTM No. 2B surfaces were harder to clean than either ASTM No. 1 or electropolished surfaces which had similar cleaning properties. A 90 0 blast angle was more effective than a 45 0 blast angle. In these tests there was no discernible effect of blast distance between 1 and 3 ft

  14. The Auburn Engineering Technical Assistance Program investigation of polyvinyl alcohol film developments pertaining to radioactive particle decontamination and industrial waste minimization

    Science.gov (United States)

    Mole, Tracey Lawrence

    In this work, an effective and systematic model is devised to synthesize the optimal formulation for an explicit engineering application in the nuclear industry, i.e. radioactive decontamination and waste reduction. Identification of an optimal formulation that is suitable for the desired system requires integration of all the interlacing behaviors of the product constituents. This work is unique not only in product design, but also in these design techniques. The common practice of new product development is to design the optimized product for a particular industrial niche and then subsequent research for the production process is conducted, developed and optimized separately from the product formulation. In this proposed optimization design technique, the development process, disposal technique and product formulation is optimized simultaneously to improve production profit, product behavior and disposal emissions. This "cradle to grave" optimization approach allowed a complex product formulation development process to be drastically simplified. The utilization of these modeling techniques took an industrial idea to full scale testing and production in under 18 months by reducing the number of subsequent laboratory trials required to optimize the formula, production and waste treatment aspects of the product simultaneously. This particular development material involves the use of a polymer matrix that is applied to surfaces as part of a decontamination system. The polymer coating serves to initially "fix" the contaminants in place for detection and ultimate elimination. Upon mechanical entrapment and removal, the polymer coating containing the radioactive isotopes can be dissolved in a solvent processor, where separation of the radioactive metallic particles can take place. Ultimately, only the collection of divided solids should be disposed of as nuclear waste. This creates an attractive alternative to direct land filling or incineration. This philosophy also

  15. Nuclear waste: our radioactive hot potato

    International Nuclear Information System (INIS)

    Conselman, F.B.

    1984-01-01

    Nuclear industry inevitably produces nuclear waste, whose prudent, prompt and economic disposal is important to the national welfare. Technological problems of containment and isolation have apparently been solved. Underground or geologic disposal sites have the potential form permanent isolation, with salt, basalt, granite, shale, and tuff currently receiving principal attention as repository host rocks. Bedded salt deposits may offer the principal mechanical advantages, but in the northwestern United States the abundance of basalt at existing test sites has made it the subject of experimentation. However, psychological, political, and allegedly environmental obstructionism have stalled the process and virtually immobilized current construction. A program is suggested with the purpose of satisfying technical requirements for public protection while allaying the exaggerated fears of anti-nuclear factions

  16. Radioactivity and United Kingdom estuaries: an overview identifying research priorities

    International Nuclear Information System (INIS)

    Hamilton, E.I.; Clifton, R.J.; Stevens, H.E.

    1985-05-01

    The report consists of the results of an evaluation of research priorities for the environmental radioactivity of estuaries, (and near shore waters) of the United Kingdom. The format of this report is:(i) general conclusions for the future requirements for research in the field of environmental radioactivity; (ii) an overview of some specific recommendations for research; and (iii) an appendix in which a comprehensive evaluation of the research priorities for specific areas of research are given. On the basis that man is the prime target for concern and protection, special attention has been given to the environment in the vicinity of the British Nuclear Fuels (BNFL) reprocessing plant at Sellafield, Cumbria, which is the source of major releases of a variety of radionuclides into the natural environment. Subjects covered in the Appendix are: site factors; pathways to man; source term; hot particles; terrestrial inputs; surveys and monitoring; analysis; organics; field versus laboratory data; biology; bioaccumulation factors; some bioaccumulators of radioactivity; bioturbation; bacteria; genetics; natural change; sediment; resuspension; surfaces; Ksub(d) factors; pore liquids; diagenesis and the ageing processes; airborne transport of radionuclides; models; natural radioactivity; public opinion; recreation; the ICRP; the ALARA principle; decommissioning of nuclear power stations; identification of research requirements; environmental radioactivity - the national effort. (U.K.)

  17. Suppression of sawtooth oscillations due to hot electrons and hot ions

    International Nuclear Information System (INIS)

    Zhang, Y.Z.; Berk, H.L.

    1989-01-01

    The theory of m = 1 kink mode stabilization is discussed in the presence of either magnetically trapped hot electrons or hot ions. For instability hot ion requires particles peaked inside the q = 1 surface, while hot electrons require that its pressure profile be increasing at the q = 1 surface. Experimentally observed sawtooth stabilization usually occurs with off-axis heating with ECRH and near axis heating with ICRH. Such heating may produce the magnetically trapped hot particle pressure profiles that are consistent with theory. 17 refs., 2 figs

  18. Design of good manufacturing facility for sterile radioactive pharmaceuticals

    International Nuclear Information System (INIS)

    Shin, B.C.; Choung, W.M.; Park, S.H.; Lee, K.I.; Park, J.H.; Park, K.B.

    2002-01-01

    Based on the GMP codes for radiopharmaceuticals in U.K. and some advanced countries, suitable guidelines for the production facility have been established and followed them up. The facility designs were fairly modified to maintain cleanliness criteria for installation in the existing radioisotope production facilities which are installed only in radiation safety points of view. Detailed design brief was drawn up by the Hyundai Engineering staffs, on the basis of initial planning and conceptual design was carried out by authors. Hot cells were installed in preparation room for radioactive handling. As hot cells under negative air pressure are not properly airtight, the surrounding environment was designed to keep less than class 10,000. Hot cells were designed to maintain less than class 1 0,000 and partially less than class 1 00 for production of sterile products. Final products will be autoclaved for sterilization after filling. To avoid contamination by microorganisms and particles of surrounding area, air curtain with vertical laminar flow will be installed between anteroom and corridor. In a pharmaceutical environment, the main consideration is the protection of the product. Thus, work station is held above ambient pressure. However, when handling radioactive materials, air pressure for work station should be lower than in surrounding areas to protect the operators and the remainder of the facility from airborne radioactive contamination. As Radiopharmaceuticals are radioactive materials for medical use, changing room could be held higher pressure than any other zones. It is expected that the facility will be effectively used for both routine preparation and research for sterile radiopharmaceuticals. (Author)

  19. Using radioactivity

    International Nuclear Information System (INIS)

    1982-10-01

    The leaflet discusses the following: radioactivity; radioisotopes; uses of ionising radiations; radioactivity from (a) naturally occurring radioactive elements, and (b) artificially produced radioisotopes; uses of radioactivity in medicine, (a) clinical diagnostic, (b) therapeutic (c) sterilization of medical equipment and materials; environmental uses as tracers; industrial applications, e.g. tracers and radiography; ensuring safety. (U.K.)

  20. Multifragmentation of hot nuclei

    International Nuclear Information System (INIS)

    Tamain, B.

    1990-10-01

    It is difficult to deposit a large amount (∼ 1 Gev) of excitation energy into a nucleus. And if one wants to deposit large excitation energy values, the best way consists of shooting a given target nucleus with several nucleons, which can be achieved by using intermediate energy (10-100 MeV/nucleon) heavy ions. Such very excited objects were named hot nuclei. The study of hot nuclei has been undertaken only for 7 years because intermediate energy heavy ion facilities were not available before. The game is then to determine the decay properties of such nuclei, their limits of existence. Their study is connected with general properties of nuclear matter: namely its equation of state. Of special interest, is the onset of a new decay mechanism: multifragmentation, which is the non-sequential disassembly of a hot nucleus into several light nuclei (often called intermediate-mass fragments or IMF) or particles. This paper, shows how this mechanism can reflect fundamental properties of nuclear matter, but also how its experimental signature is difficult to establish. Multifragmentation has also been studied by using very energetic projectiles (protons and heavy ions) in the relativistic or ultra-relativistic region. The multifragmentation question of hot nuclei is far from being solved. One knows that IMF production increases when the excitation energy brought into a system is strongly increased, but very little is known about the mechanisms involved and a clear onset for multifragmentation is not established

  1. Remote Laser Diffraction Particle Size Distribution Analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Batcheller, Thomas Aquinas; Huestis, Gary Michael; Bolton, Steven Michael

    2001-03-01

    In support of a radioactive slurry sampling and physical characterization task, an “off-the-shelf” laser diffraction (classical light scattering) particle size analyzer was utilized for remote particle size distribution (PSD) analysis. Spent nuclear fuel was previously reprocessed at the Idaho Nuclear Technology and Engineering Center (INTEC—formerly recognized as the Idaho Chemical Processing Plant) which is on DOE’s INEEL site. The acidic, radioactive aqueous raffinate streams from these processes were transferred to 300,000 gallon stainless steel storage vessels located in the INTEC Tank Farm area. Due to the transfer piping configuration in these vessels, complete removal of the liquid can not be achieved. Consequently, a “heel” slurry remains at the bottom of an “emptied” vessel. Particle size distribution characterization of the settled solids in this remaining heel slurry, as well as suspended solids in the tank liquid, is the goal of this remote PSD analyzer task. A Horiba Instruments Inc. Model LA-300 PSD analyzer, which has a 0.1 to 600 micron measurement range, was modified for remote application in a “hot cell” (gamma radiation) environment. This technology provides rapid and simple PSD analysis, especially down in the fine and microscopic particle size regime. Particle size analysis of these radioactive slurries down in this smaller range was not previously achievable—making this technology far superior than the traditional methods used. Successful acquisition of this data, in conjunction with other characterization analyses, provides important information that can be used in the myriad of potential radioactive waste management alternatives.

  2. Thule-2003 - Investigation of radioactive contamination

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Sven P.; Roos, P.

    2006-05-15

    Analyses of marine and terrestrial samples collected in August 2003 from Bylot Sound at Thule, Northwest Greenland, show that plutonium from nuclear weapons in the American B52 plane, which crashed on the sea ice in January 1968, persists in the environment. The highest concentrations of plutonium are found in the marine sediments under the location where the plane crashed. The distribution of plutonium in the marine sediment is very inhomogeneous and associated with hot particles with activities found up to 1500 Bq {sup 239,240}Pu. Sediment samples collected in Wolstenholme Fjord north of the accident site show plutonium concentrations, which illustrates the redistribution of plutonium after the accident. The total plutonium inventory in the sediments has been assessed based on systematic analyses considering hot particles. The inventory of {sup 239,240}Pu in the sediments within a distance of 17 km from the point of impact of the B52 plane is estimated at 2.9 TBq (1 kg). Earlier estimates of the inventory were approximately 1.4 TBq {sup 239,240}Pu. Seawater and seaweed samples show increased concentrations of plutonium in Bylot Sound. The increased concentrations are due to resuspension of plutonium-containing particles from the seabed and transport further away from the area. Plutonium concentrations in seawater, seaweed and benthic animals in Bylot Sound are low but clearly above background levels. All soil samples collected from Narssarssuk show accident plutonium with levels above background. Plutonium is very inhomogeneously distributed and associated with particles in the surface layers. Hot particles were found in soil with activities up to 150 Bq {sup 239,240}Pu. Plutonium in the marine environment at Thule presents an insignificant risk to man. Most plutonium remains in the seabed under Bylot Sound far from man under relatively stable conditions and concentrations of plutonium in seawater and animals are low. However, the plutonium contamination of

  3. Thule-2003 - Investigation of radioactive contamination

    International Nuclear Information System (INIS)

    Nielsen, Sven P.; Roos, P.

    2006-05-01

    Analyses of marine and terrestrial samples collected in August 2003 from Bylot Sound at Thule, Northwest Greenland, show that plutonium from nuclear weapons in the American B52 plane, which crashed on the sea ice in January 1968, persists in the environment. The highest concentrations of plutonium are found in the marine sediments under the location where the plane crashed. The distribution of plutonium in the marine sediment is very inhomogeneous and associated with hot particles with activities found up to 1500 Bq 239,240 Pu. Sediment samples collected in Wolstenholme Fjord north of the accident site show plutonium concentrations, which illustrates the redistribution of plutonium after the accident. The total plutonium inventory in the sediments has been assessed based on systematic analyses considering hot particles. The inventory of 239,240 Pu in the sediments within a distance of 17 km from the point of impact of the B52 plane is estimated at 2.9 TBq (1 kg). Earlier estimates of the inventory were approximately 1.4 TBq 239,240 Pu. Seawater and seaweed samples show increased concentrations of plutonium in Bylot Sound. The increased concentrations are due to resuspension of plutonium-containing particles from the seabed and transport further away from the area. Plutonium concentrations in seawater, seaweed and benthic animals in Bylot Sound are low but clearly above background levels. All soil samples collected from Narssarssuk show accident plutonium with levels above background. Plutonium is very inhomogeneously distributed and associated with particles in the surface layers. Hot particles were found in soil with activities up to 150 Bq 239,240 Pu. Plutonium in the marine environment at Thule presents an insignificant risk to man. Most plutonium remains in the seabed under Bylot Sound far from man under relatively stable conditions and concentrations of plutonium in seawater and animals are low. However, the plutonium contamination of surface soil at

  4. The design of hot laboratories

    International Nuclear Information System (INIS)

    1976-01-01

    The need for specialized laboratories to handle radioactive substances of high activity has increased greatly due to the expansion of the nuclear power industry and the widespread use of radioisotopes in scientific research and technology. Such laboratories, which are called hot laboratories, are specially designed and equipped to handle radioactive materials of high activity, including plutonium and transplutonium elements. The handling of plutonium and transplutonium elements presents special radiation-protection and safety problems because of their high specific activity and high radiotoxicity. Therefore, the planning, design, construction and operation of hot laboratories must meet the stringent safety, containment, ventilation, shielding, criticality control and fire-protection requirements. The IAEA has published two manuals in its Safety Series, one on the safety aspects of design and equipment of hot laboratories (SS No.30) and the other on the safe handling of plutonium (SS No.39). The purpose of the symposium in Otaniemi was to collect information on recent developments in the safety features of hot laboratories and to review the present state of knowledge. A number of new developments have taken place as the result of growing sophistication in the philosophy of radiation protection as given in the ICRP recommendations (Report No.22) and in the Agency's basic safety standards (No.9). The topics discussed were safety features of planning and design, air cleaning, transfer and transport systems, criticality control, fire protection, radiological protection, waste management, administrative arrangements and operating experience

  5. HOT 2017

    DEFF Research Database (Denmark)

    Hannibal, Sara Stefansen

    HOT er en kvalitativ undersøgelse, der hvert år diskuterer og undersøger en lille udvalgt skare af danskkyndige fagpersoners bud på, hvad de er optagede af på literacyområdet her og nu – altså hvilke emner, de vil vurdere som aktuelle at forholde sig til i deres nuværende praksis.......HOT er en kvalitativ undersøgelse, der hvert år diskuterer og undersøger en lille udvalgt skare af danskkyndige fagpersoners bud på, hvad de er optagede af på literacyområdet her og nu – altså hvilke emner, de vil vurdere som aktuelle at forholde sig til i deres nuværende praksis....

  6. Radioactive isotopes on the Moon

    International Nuclear Information System (INIS)

    Davis, R. Jr.

    1975-01-01

    A limited review of experiments and studies of radioactivity and isotope ratios in lunar materials is given. Observations made on the first few millimeters of the surface where the effects of solar flare particles are important, some measurements on individual rocks, and some studies of radioactivities produced deep in the lunar soil by galactic cosmic rays, are among the experiments discussed

  7. Hot and Dry Cleaning of Biomass-Gasified Gas Using Activated Carbons with Simultaneous Removal of Tar, Particles, and Sulfur Compounds

    Directory of Open Access Journals (Sweden)

    Kinya Sakanishi

    2012-05-01

    Full Text Available This study proposes a gas-cleaning process for the simultaneous removal of sulfur compounds, tar, and particles from biomass-gasified gas using Fe-supported activated carbon and a water-gas shift reaction. On a laboratory scale, the simultaneous removal of H2S and COS was performed under a mixture of gases (H2/CO/CO2/CH4/C2H4/N2/H2S/COS/steam. The reactions such as COS + H2 → H2S + CO and COS + H2O → H2S + CO2 and the water-gas shift reaction were promoted on the Fe-supported activated carbon. The adsorption capacity with steam was higher than that without steam. On a bench scale, the removal of impurities from a gas derived from biomass gasification was investigated using two activated filters packed with Fe-supported activated carbon. H2S and COS, three- and four-ring polycyclic aromatic hydrocarbons (PAHs, and particles were removed and a water-gas shift reaction was promoted through the first filter at 320–350 °C. The concentrations of H2S and COS decreased to less than 0.1 ppmv. Particles and the one- and two-ring PAHs, except for benzene, were then removed through the second filter at 60–170 °C. The concentration of tar and particles decreased from 2428 to 102 mg Nm−3 and from 2244 to 181 mg Nm−3, respectively.

  8. Radioactive source

    International Nuclear Information System (INIS)

    Drabkina, L.E.; Mazurek, V.; Myascedov, D.N.; Prokhorov, P.; Kachalov, V.A.; Ziv, D.M.

    1976-01-01

    A radioactive layer in a radioactive source is sealed by the application of a sealing layer on the radioactive layer. The sealing layer can consist of a film of oxide of titanium, tin, zirconium, aluminum, or chromium. Preferably, the sealing layer is pure titanium dioxide. The radioactive layer is embedded in a finish enamel which, in turn, is on a priming enamel which surrounds a substrate

  9. Comparative solubilisation of potassium carbonate, sodium bicarbonate and sodium carbonate in hot dimethylformamide: application of cylindrical particle surface-controlled dissolution theory.

    Science.gov (United States)

    Forryan, Claire L; Compton, Richard G; Klymenko, Oleksiy V; Brennan, Colin M; Taylor, Catherine L; Lennon, Martin

    2006-02-07

    A surface-controlled dissolution of cylindrical solid particles model is applied to potassium carbonate, sodium bicarbonate and sodium carbonate in dimethylformamide at elevated temperatures. Previously published data for the dissolution of potassium carbonate is interpreted assuming a cylindrical rather than a spherical shape of the particles, the former representing a closer approximation to the true shape of the particles as revealed by scanning electron microscopy. The dissolution kinetics of sodium carbonate and sodium bicarbonate in dimethylformamide at 100 degrees C were investigated via monitoring of the deprotonation of 2-cyanophenol with dissolved solid to form the 2-cyanophenolate anion that was detected with UV-visible spectroscopy. From fitting of experimental results to theory, the dissolution rate constant, k, for the dissolutions of potassium carbonate, sodium bicarbonate and sodium carbonate in dimethylformamide at 100 degrees C were found to have the values of (1.0 +/- 0.1) x 10(-7) mol cm(-2) s(-1), (5.5 +/- 0.3) x 10(-9) mol cm(-2) s(-1) and (9.7 +/- 0.8) x 10(-9) mol cm(-2) s(-1), respectively.

  10. Radioactivity metrology

    International Nuclear Information System (INIS)

    Legrand, J.

    1979-01-01

    Some aspects of the radioactivity metrology are reviewed. Radioactivity primary references; absolute methods of radioactivity measurements used in the Laboratoire de Metrologie des Rayonnements Ionisants; relative measurement methods; traceability through international comparisons and interlaboratory tests; production and distribution of secondary standards [fr

  11. Radioactive wastes

    International Nuclear Information System (INIS)

    Teillac, J.

    1988-01-01

    This study of general interest is an evaluation of the safety of radioactive waste management and consequently the preservation of the environment for the protection of man against ionizing radiations. The following topics were developed: radiation effects on man; radioactive waste inventory; radioactive waste processing, disposal and storage; the present state and future prospects [fr

  12. Tobacco radioactivity and cancer in smokers

    International Nuclear Information System (INIS)

    Martell, E.A.

    1975-01-01

    The recent finding that 210 Pb, which also is present in inhaled mainstream smoke, is highly concentrated in a small number of insoluble smoke particles changes the whole complexion of the problem of possible health effects of the inhaled radioactivity in cigarette smoke. Because 210 Pb has a radioactive half-life of 22 years, the body burden of the radioactive 210 Pb and its radioactive daughter products 210 Bi and 210 Po can continue to build up throughout the period of smoking. Alpha interactions with chromosomes of cells surrounding these insoluble radioactive smoke particles may cause cancer and contribute to early atherosclerosis development in cigarette smokers. (U.S.)

  13. Radioactive battery

    International Nuclear Information System (INIS)

    Deaton, R.L.; Silver, G.L.

    1975-01-01

    A radioactive battery is described that is comprised of a container housing an electrolyte, two electrodes immersed in the electrolyte and insoluble radioactive material disposed adjacent one electrode. Insoluble radioactive material of different intensity of radioactivity may be disposed adjacent the second electrode. If hydrobromic acid is used as the electrolyte, Br 2 will be generated by the radioactivity and is reduced at the cathode: Br 2 + 2e = 2 Br - . At the anode Br - is oxidized: 2Br - = Br 2 + 2e. (U.S.)

  14. Nuclear prehistory influence on transfer velocity of 54Mn impurity 'hot' atoms in irradiated metallic iron

    International Nuclear Information System (INIS)

    Alekseev, I.E.

    2007-01-01

    Influence of nuclear prehistory on transfer velocity of 54 Mn impurity 'hot'-atoms - got by different nuclear channels: 56 Fe(d, α), 54 Fe(n,p) in irradiated metallic iron - is studied. Irradiation of targets were carried out in U-120 accelerator (energy range 7.3/5.3 MeV, deuteron beam current makes up 5 μA). Mean density of thermal neutron (WWR-M reactor) makes up 8.6·10 13 neutron·cm -2 ·s -1 . It is shown, that transfer velocity of 54 Mn 'hot' atoms is defining by rate of radiation damage of targets in the irradiation process at that a key importance has a bombarding particles type applied for radioactive label getting

  15. Microfiltration of radioactive contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, L P; Slade, J A; Vijayan, S; Wong, C F

    1993-04-01

    Cross-flow microfiltration processing of radioactive liquids has been in use at Chalk River Laboratories for about four years. The separation process removes suspended particles from radioactive waste solutions. The clean liquid can then be treated with conventional reverse osmosis membranes to achieve volume reduction factors approaching 100. Microfiltration removes particles below the rating of 0.2 microns, in part from particle agglomeration. Operating experience relating to a 15 USGPM unit is presented. Coupling microfiltration technology with chemical treatment enhances the removal of soluble species. Research and development experience with the removal of soluble contaminants found in ground water and waste water will be discussed. The technology has advantages over other membrane technologies, namely lower energy costs, a lesser degree of fouling, and a higher recovery of processed solution. Future applications of the technology are addressed. (author). 10 refs., 3 tabs., 4 figs.

  16. Microfiltration of radioactive contaminants

    International Nuclear Information System (INIS)

    Buckley, L.P.; Slade, J.A.; Vijayan, S.; Wong, C.F.

    1993-04-01

    Cross-flow microfiltration processing of radioactive liquids has been in use at Chalk River Laboratories for about four years. The separation process removes suspended particles from radioactive waste solutions. The clean liquid can then be treated with conventional reverse osmosis membranes to achieve volume reduction factors approaching 100. Microfiltration removes particles below the rating of 0.2 microns, in part from particle agglomeration. Operating experience relating to a 15 USGPM unit is presented. Coupling microfiltration technology with chemical treatment enhances the removal of soluble species. Research and development experience with the removal of soluble contaminants found in ground water and waste water will be discussed. The technology has advantages over other membrane technologies, namely lower energy costs, a lesser degree of fouling, and a higher recovery of processed solution. Future applications of the technology are addressed. (author). 10 refs., 3 tabs., 4 figs

  17. Disposal of radioactive wastes from Czechoslovak nuclear power plants

    International Nuclear Information System (INIS)

    Neumann, L.

    In gaseous radioactive waste disposal, aerosol particles are filtered and gaseous wastes are discharged in the environment. The filters and filter materials used are stored on solid radioactive waste storage sites in the individual power plants. Liquid radioactive wastes are concentrated and the concentrates are stored. Distillates and low-level radioactive waste water are discharged into the hydrosphere. Solid radioactive wastes are stored without treatment in power plant bunkers. Bituminization and cementation of liquid radioactive wastes are discussed. (H.S.)

  18. Handbook of radioactivity measurements procedures. Second edition

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    This report is concerned with the measurement of radioactivity in general, but specifically it deals with radioactive materials that have become available in the last three decades, from nuclear reactors and particle accelerators, for applications in medicine, scientific research, and industry. It is also concerned with low-level radioactivity measurements for the monitoring of radioactivity in environmental media, such as air and water, in connection with the control of radioactive effluents associated with the production of nuclear power or the use of radionuclides. Included in appendices are nuclear decay data for selected radionuclides and statistics of radioactive decay. An extensive bibliography is also included

  19. The formation and deexcitation of hot nuclei in 40Ar + 197Au collisions at 44 and 77 MeV/A. Neutrons emission light charged particles and complex fragments

    International Nuclear Information System (INIS)

    Sokolov, A.

    1990-05-01

    This work is a contribution to the study of the formation and decay of hot nuclei produced in heavy ion collisions at intermediate energies. By studying the system Ar + Au and Ar + Th at 44 MeV/u and 77 MeV/u we first show how to classify events in two groups: peripheral and very dissipative collisions, measuring the number of evaporated neutrons, which depend directly on the violence of the collision. Associated with these neutrons, different deexcitation channels were observed (heavy residues, fission fragments, light charged particles, intermediate mass fragments). The ratio between peripheral and very dissipative collisions was found independent of the system and the same as the one observed at lower incident energy. The most probable neutron multiplicity for very dissipative collisions is not very different at 44 MeV/u and 77 MeV/u. A measurement of the angular distribution of fission fragments and heavy residues was performed. Detected products are essentially associated with large neutron multiplicity and have a cross section close to the one for the very dissipative collisions. The total mass of the fission fragments is close to the mass of the target, while the mass of the heavy residue is much smaller. The backward evaporated light charged particles are also produced in very dissipative collisions. The characteristics of their energy spectra as well as their multiplicities are very similar at 44 MeV/u 77 MeV/u. From the number of evaporated light charged particles, the estimation of the quasi-target excitation energy was done and found to be close to 600 MeV at 44 MeV/u and 77 MeV/u [fr

  20. Experimental determination of the steady-state charging probabilities and particle size conservation in non-radioactive and radioactive bipolar aerosol chargers in the size range of 5–40 nm

    Energy Technology Data Exchange (ETDEWEB)

    Kallinger, Peter, E-mail: peter.kallinger@univie.ac.at; Szymanski, Wladyslaw W. [University of Vienna, Faculty of Physics (Austria)

    2015-04-15

    Three bipolar aerosol chargers, an AC-corona (Electrical Ionizer 1090, MSP Corp.), a soft X-ray (Advanced Aerosol Neutralizer 3087, TSI Inc.), and an α-radiation-based {sup 241}Am charger (tapcon & analysesysteme), were investigated on their charging performance of airborne nanoparticles. The charging probabilities for negatively and positively charged particles and the particle size conservation were measured in the diameter range of 5–40 nm using sucrose nanoparticles. Chargers were operated under various flow conditions in the range of 0.6–5.0 liters per minute. For particular experimental conditions, some deviations from the chosen theoretical model were found for all chargers. For very small particle sizes, the AC-corona charger showed particle losses at low flow rates and did not reach steady-state charge equilibrium at high flow rates. However, for all chargers, operating conditions were identified where the bipolar charge equilibrium was achieved. Practically, excellent particle size conservation was found for all three chargers.

  1. New radioactivities

    International Nuclear Information System (INIS)

    Greiner, W.; Sandulescu, A.

    1996-01-01

    Some atomic nuclei reorganize their structure by ejection of big protons and neutrons aggregates. The observation of these new radioactivities specifies the theories of the nuclear dynamics. (authors)

  2. Radioactive materials

    International Nuclear Information System (INIS)

    Sugiura, Yoshio; Shimizu, Makoto.

    1975-01-01

    The problems of radioactivity in the ocean with marine life are various. Activities in this field, especially the measurements of the radioactivity in sea water and marine life are described. The works first started in Japan concerning nuclear weapon tests. Then the port call to Japan by U.S. nuclear-powered naval ships began. On the other hand, nuclear power generation is advancing with its discharge of warm water. The radioactive pollution of sea water, and hence the contamination of marine life are now major problems. Surveys of the sea areas concerned and study of the radioactivity intake by fishes and others are carried out extensively in Japan. (Mori, K.)

  3. Radioactivity Handbook

    International Nuclear Information System (INIS)

    Firestone, R.B.; Browne, E.

    1985-01-01

    The Radioactivity Handbook will be published in 1985. This handbook is intended primarily for applied users of nuclear data. It will contain recommended radiation data for all radioactive isotopes. Pages from the Radioactivity Handbook for A = 221 are shown as examples. These have been produced from the LBL Isotopes Project extended ENDSF data-base. The skeleton schemes have been manually updated from the Table of Isotopes and the tabular data are prepared using UNIX with a phototypesetter. Some of the features of the Radioactivity Handbook are discussed here

  4. Radioactive liquid waste filtering device

    International Nuclear Information System (INIS)

    Inami, Ichiro; Tabata, Masayuki; Kubo, Koji.

    1988-01-01

    Purpose: To prevent clogging in filter materials and improve the filtration performance for radioactive liquid wastes without increasing the amount of radioactive wastes. Constitution: In a radioactive waste filtering device, a liquid waste recycling pipe and a liquid recycling pump are disposed for recycling the radioactive liquid wastes in a liquid wastes vessel. In this case, the recycling pipe and the recycling pump are properly selected so as to satisfy the conditions capable of making the radioactive liquid wastes flowing through the pipe to have the Reynolds number of 10 4 - 10 5 . By repeating the transportation of radioactive liquid wastes in the liquid waste vessel through the liquid waste recycling pipe by the liquid waste recycling pump and then returning them to the liquid waste vessel again, particles of fine grain size in the suspended liquids are coagulated with each other upon collision to increase the grain size of the suspended particles. In this way, clogging of the filter materials caused by the particles of fine grain size can be prevented, thereby enabling to prevent the increase in the rising rate of the filtration differential pressure, reduce the frequency for the occurrence of radioactive wastes such as filter sludges and improve the processing performance. (Kamimura, M.)

  5. Radioactivity. Centenary of radioactivity discovery

    International Nuclear Information System (INIS)

    Charpak, G.; Tubiana, M.; Bimbot, R.

    1997-01-01

    This small booklet was edited for the occasion of the exhibitions of the celebration of the centenary of radioactivity discovery which took place in various locations in France from 1996 to 1998. It recalls some basic knowledge concerning radioactivity and its applications: history of discovery, atoms and isotopes, radiations, measurement of ionizing radiations, natural and artificial radioactivity, isotope dating and labelling, radiotherapy, nuclear power and reactors, fission and fusion, nuclear wastes, dosimetry, effects and radioprotection. (J.S.)

  6. Hot cell design in the vitrification plant China

    International Nuclear Information System (INIS)

    Jiang Yubo; Wang Guangkai; Zhang Wei; Liang Runan; Dou Yuan

    2015-01-01

    In the area of reprocessing and radioactive waste management, gloveboxes and cells are a kind of non-standard equipments providing an isolated room to operate radioactive material inside, while the operator outside with essential biological shield and protection. The hot cell is a typical one, which could handle high radioactive material with various operating means and tight enclosure. The dissertation is based on Vitrification Plant China, a cooperation project between China and Germany. For the sino-western difference in design philosophy, it was presented how to draft an acceptable design proposal of applicable huge hot cells by analysing the design requirements, such as radioprotection, observation, illumination, remote handling, transportation, maintenance and decontamination. The construction feasibility of hot cells was also approved. Thanks to 3D software Autodesk Inventor, digital hot cell was built to integrate all the interfaces inside, which validated the design by checking the mechanical interference. (author)

  7. Sampling airborne radioactivity

    International Nuclear Information System (INIS)

    Cohen, B.S.

    1988-01-01

    Radioactive contaminants have historically been considered apart from chemical contaminants because it is their radiological properties that determine their biological and environmental impact. Additionally they have been regulated by special government agencies concerned with radiological protection. Radioactive contaminants are also distinguished by the specialized and very sensitive methods available for the detection of radioactivity. Measurements of a few thousand atoms per liter are not uncommon. Radiation detectors in common use are gas filled chambers, scintillation and semiconductor detectors, and the more recently developed thermoluminescent and etched track detectors. Solid-state nuclear track detectors consist of a large group of inorganic and organic dielectrics which register tracks when traversed by heavy charged particles. They do not respond to light, beta particles or gamma ray photons and thus provide a very low background system for the detection of extremely low levels of radioactivity. In addition, no power source or electronic equipment is required. Cellulose nitrate detectors are currently in use for long term integrated sampling of environmental radon. Thermoluminescent dosimeters (TID's) are crystalline materials, in which electrons which have been displaced by an interaction with ionizing radiation become trapped at an elevated energy level and emit visible light when released from that energy level. As which etched-track detectors no power or electronic equipment is needed for the TID's at a measurement site, but they respond to alpha, beta and gamma radiation. Thermoluminescent dosimeters are useful for long term environmental monitoring, and have also been newly incorporated into integrating radon detection systems

  8. Ionization particle detector

    International Nuclear Information System (INIS)

    Ried, L.

    1982-01-01

    A new device is claimed for detecting particles in a gas. The invention comprises a low cost, easy to assemble, and highly accurate particle detector using a single ionization chamber to contain a reference region and a sensing region. The chamber is designed with the radioactive source near one electrode and the second electrode located at a distance less than the distance of maximum ionization from the radioactive source

  9. Treatment of radioactive sludge

    International Nuclear Information System (INIS)

    Allison, W.; Payne, B.J.; Pegler, G.E.

    1979-01-01

    Radioactive sludge e.g. that which may accumulate in irradiated nuclear fuel element storage ponds, is treated by pumping it from a settling tank to a particle separator, conveniently a hydrocyclone and a sloping plate separator, the liquid being returned to the settling tank and the solids being metered into a drum pre-lined with dry cement. The drums are in a containment box in which they are transferred to a mixing station where the particles and cement are mixed and thence to a curing station. After curing the drums are embedded in cement in outer containers for transport to a long-term storage site. (author)

  10. Characterisation study of radionuclides in Hot Cell Facility

    International Nuclear Information System (INIS)

    Ghare, P.T.; Rath, D.P.; Govalkar, Atul; Mukherjee, Govinda; AniIKumar, S.; Yadav, R.K.B.; Mallik, G.K.

    2016-01-01

    Examination of different types of experimental as well as power reactor irradiated fuels and validation of fuel modeling codes is carried out in general Hot cell facility. The Hot cell facility has six concrete shielded hot cells, capable of handling radioactivity varying from 3.7 TBQ to 3700 TBq gamma activity. The facility was augmented with two hot cells having designed capacity to handle radioactivity of 9250 TBQ of equivalent activity of 60 Co. The study of characterization of various radionuclides present inside the hot cell of PIE facility was taken up. This study will help in providing valuable inputs for various radiological safety parameters to keep personnel exposure to ALARA level as per the mandate of radiation safety program

  11. Physical limits on steam generation by radioactive decay heat

    International Nuclear Information System (INIS)

    Chesnut, D.A.

    1991-12-01

    This report briefly discusses the possibilities that flood water contacting the hot radioactive waste and rock at Yucca Mountain could produce enough steam to lift the top of the mountain off the repository

  12. Simulated Radioactivity

    Science.gov (United States)

    Boettler, James L.

    1972-01-01

    Describes the errors in the sugar-cube experiment related to radioactivity as described in Project Physics course. The discussion considers some of the steps overlooked in the experiment and generalizes the theory beyond the sugar-cube stage. (PS)

  13. Concentrating Radioactivity

    Science.gov (United States)

    Herrmann, Richard A.

    1974-01-01

    By concentrating radioactivity contained on luminous dials, a teacher can make a high reading source for classroom experiments on radiation. The preparation of the source and its uses are described. (DT)

  14. The Use of Radioactive Marker as a Tool to Evaluate the Drug Release in Plasma and Particle Biodistribution of Block Copolymer Nanoparticles

    Directory of Open Access Journals (Sweden)

    Sharon Johnstone

    2011-01-01

    Full Text Available Diblock copolymer nanoparticles encapsulating a paclitaxel prodrug, Propac 7, have been used to demonstrate the usefulness of a nonmetabolizable radioactive marker, cholesteryl hexadecyl ether (CHE, to evaluate nanoparticle formulation variables. Since CHE did not exchange out of the nanoparticles, the rate of clearance of the CHE could be used as an indicator of nanoparticle stability in vivo. We simultaneously monitored prodrug circulation and carrier circulation in the plasma and the retention of CHE relative to the retention of prodrug in the plasma was used to distinguish prodrug release from nanoparticle plasma clearance. Nanoparticles labelled with CHE were also used to evaluate accumulation of nanoparticles in the tumour. This marker has provided relevant data which we have applied to optimise our nanoparticle formulations.

  15. Fabrication of Al-based composites reinforced with in situ devitrified Al{sub 84}Ni{sub 8.4}Y{sub 4.8}La{sub 1.8}Co{sub 1} particles by hot pressing consolidation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Qing, E-mail: buaayq00@gmail.com; Zhang, Yitan; Zhang, Haiping; Zheng, Ruixiao; Xiao, Wenlong; Ma, Chaoli, E-mail: machaoli@buaa.edu.cn

    2015-11-05

    In this study, Al{sub 84}Ni{sub 8.4}Y{sub 4.8}La{sub 1.8}Co{sub 1} particles reinforced Al-based composites were prepared by hot pressing sintering and subsequent hot extrusion. The glassy powders were produced by gas atomization and then employed to mechanical milling. After hot pressing sintering, the nano-scale intermetallic compounds precipitated from metallic glass matrix due to higher temperature than super-cooled liquid region. The mechanical properties of 2024 alloy were improved by addition of glassy particles. The ultimate compressive stress increased from 482 MPa for 2024 alloy to 545 MPa, 627 MPa and 735 MPa for composites with 20 w.t.% 40 w.t.% and 60 w.t.% glassy powders addition, respectively, together with considerable fracture strain ranging between 2.9% and 13.6%. And the mechanical properties could be predicted by using the Rule of Mixture, which predicts the mechanical properties of the bulks from the volume weighed average of the constituent properties. - Highlights: • The composites are fabricate by hot pressing and extrusion. • The single phase of amorphous alloy is obtained by sieving. • The nano-scale compounds precipitates from glassy matrix. • The compressive strength reaches to the value of 735 MPa. • The strength can fit well with rule of mixture.

  16. Radioactive wastes

    International Nuclear Information System (INIS)

    Grass, F.

    1982-01-01

    Following a definition of the term 'radioactive waste', including a discussion of possible criteria allowing a delimitation of low-level radioactive against inactive wastes, present techniques of handling high-level, intermediate-level and low-level wastes are described. The factors relevant for the establishment of definitive disposals for high-level wastes are discussed in some detail. Finally, the waste management organization currently operative in Austria is described. (G.G.)

  17. Radioactive pollution

    International Nuclear Information System (INIS)

    Steiner, R.

    1987-01-01

    In the wake of the Chernobyl reactor accident on April 26, 1986, many individual values for radioactivity in the air, in foodstuffs and in the soil were measured and published. Prof. Dr. Rolf Steiner, Wiesbaden, the author of this paper, evaluated the host of data - mostly official pollution data -, drew conclusions regarding the radioactivity actually released at Chernobyl, and used the data to test the calculation model adotped by the Radiation Protection Ordinance. (orig./RB) [de

  18. Solar 'hot spots' are still hot

    Science.gov (United States)

    Bai, Taeil

    1990-01-01

    Longitude distributions of solar flares are not random but show evidence for active zones (or hot spots) where flares are concentrated. According to a previous study, two hot spots in the northern hemisphere, which rotate with a synodic period of about 26.72 days, produced the majority of major flares, during solar cycles 20 and 21. The more prominent of these two hot spots is found to be still active during the rising part of cycle 22, producing the majority of northern hemisphere major flares. The synodic rotation period of this hot spot is 26.727 + or - 0.007 days. There is also evidence for hot spots in the southern hemisphere. Two hot spots separated by 180 deg are found to rotate with a period of 29.407 days, with one of them having persisted in the same locations during cycles 19-22 and the other, during cycles 20-22.

  19. Solar hot spots are still hot

    International Nuclear Information System (INIS)

    Bai, T.

    1990-01-01

    Longitude distributions of solar flares are not random but show evidence for active zones (or hot spots) where flares are concentrated. According to a previous study, two hot spots in the northern hemisphere, which rotate with a synodic period of about 26.72 days, produced the majority of major flares, during solar cycles 20 and 21. The more prominent of these two hot spots is found to be still active during the rising part of cycle 22, producing the majority of northern hemisphere major flares. The synodic rotation period of this hot spot is 26.727 + or - 0.007 days. There is also evidence for hot spots in the southern hemisphere. Two hot spots separated by 180 deg are found to rotate with a period of 29.407 days, with one of them having persisted in the same locations during cycles 19-22 and the other, during cycles 20-22. 14 refs

  20. Radioactivity. Death prinicple in nature

    International Nuclear Information System (INIS)

    Russell, W.; Russell, L.

    2006-01-01

    Walter Russell's knowledge of the two basic Principles of the material universe, concentration and radiation, strongly suggests that the radioactivity is the ''death principle'' of creation. In its natural environment, radioactive radiation is vital for the overall balance, however, when spread out across the entire world, it causes massive global warming and turns planet earth into a hot desert. Part I: What is Atomic Energy?; How Radioactivity Kills; The World Voice. Part II: The True Nature of This Mind and Motion Universe; Prelude - The Transformation of Man; We Define God; The True Nature of Electricity and Gravitation; Our Eternal Universe; The Oneness of Gravity and Magnetism; The Mind Nucleus of the Atom; The Material Nucleus of the Atom. Part III: The Bridge Between Man and God. (orig./GL)

  1. Effect Of Particle Size Of Zeolite On The Mass Transfer Coefficient Of Strontium In The Radioactive Waste Ion-Exchange Process

    International Nuclear Information System (INIS)

    Dewi-Susilowati; Suyitno

    1998-01-01

    This research is aimed for finding out the volumetric mass transfer coefficient of the zeolite particle, ks. The experiment has been conducted using an ion exchange column. The column diameter and length are 4.2 cm and 28 cm, respectively. The experiments have been conducted by flowing in the feed to the ion-exchange column containing zeolite with the varied particle diameters, I.e. 20, 40, 60, 80 and 100 mesh. The feed concentrations of Sr(NO 3 ) 2 , have been varied, I.e. 100, 250, 450, 550 and 650 ppm, and so have been the flow rates, I.e/ 35, 49, 70, 90 and 105 ml/minute. Samples of the effluents have been taken at certain series of time and subjected to analysis using an Atomic Absorption Spectrophotometer. The analytical data obtained have shown that the mass transfer coefficient of the zeolite particle is predominantly affected by the zeolite structure, in particular is effected by the number of AI atoms that hold the K ions. The analytical result from the above parameters has been presented in the forms of several groups of dimensionless number. The equations obtained are: (k L *dp)/D L 18.902(Re) 0 ,378 (dp/D) 0 ,6972(Co * ) 0 ,2667 with a mean error of 7.26%; k S 2240.268(dp/D) 1 .553; and each of them is valid in range of: Re: 0.182 - 0.856; dp/D: 0.004 - 0.022; Co * : 9.5408x10 - 5 - 6.2827x10 - 4

  2. Web technology in the separation of strontium and cesium from INEL-ICPP radioactive acid waste (WM-185)

    International Nuclear Information System (INIS)

    Bray, L.A.; Brown, G.N.

    1995-01-01

    Strontium and cesium were successfully removed from radioactive acidic waste (WM-185) at the Idaho National Engineering Laboratory, Idaho Chemical Processing Plant (ICPP), with web technology from 3M and IBC Advanced Technologies, Inc. (IBC). A technical team from Pacific Northwest Laboratory, ICPP, 3M and IBC conducted a very successful series of experiments from August 15 through 18, 1994. The ICPP, Remote Analytical Laboratory, Idaho Falls, Idaho, provided the hot cell facilities and staff to complete these milestone experiments. The actual waste experiments duplicated the initial 'cold' simulated waste results and confirmed the selective removal provided by ligand-particle web technology

  3. Radioactive wastes

    International Nuclear Information System (INIS)

    Dupuis, M.C.

    2007-01-01

    Managing radioactive wastes used to be a peripheral activity for the French atomic energy commission (Cea). Over the past 40 years, it has become a full-fledged phase in the fuel cycle of producing electricity from the atom. In 2005, the national radioactive waste management agency (ANDRA) presented to the government a comprehensive overview of the results drawn from 15 years of research. This landmark report has received recognition beyond France's borders. By broadening this agency's powers, an act of 28 June 2006 acknowledges the progress made and the quality of the results. It also sets an objective for the coming years: work out solutions for managing all forms of radioactive wastes. The possibility of recovering wastes packages from the disposal site must be assured as it was asked by the government in 1998. The next step will be the official demand for the creation of a geological disposal site in 2016

  4. Method removing radioactivity from kaolin

    International Nuclear Information System (INIS)

    Conley, R.F.

    1978-01-01

    A method of reducing the radioactivity found in naturally occurring kaolins to about 40% below its native value, and the leachable radiogenic components to less than 20% is described. This reduction is achieved by removing from the kaolin particles of a size less than 0.5 microns. This removal may be carried out by gravitational settling, flocculation of non-colloidal particles, or acid leaching

  5. Simulation studies on stability of hot electron plasma

    International Nuclear Information System (INIS)

    Ohsawa, Yukiharu

    1985-01-01

    Stability of a hot electron plasma in an NBT(EBT)-like geometry is studied by using a 2-1/2 dimensional relativistic, electromagnetic particle code. For the low-frequency hot electron interchange mode, comparison of the simulation results with the analytical predictions of linear stability theory show fairly good agreement with the magnitude of the growth rates calculated without hot electron finite Larmor radius effects. Strong stabilizing effects by finite Larmor radius of the hot electrons are observed for short wavelength modes. As for the high-frequency hot electron interchange mode, there is a discrepancy between the simulation results and the theory. The high-frequency instability is not observed though a parameter regime is chosen in which the high-frequency hot electron interchange mode is theoretically predicted to grow. Strong cross-field diffusion in a poloidal direction of the hot electrons might explain the stability. Each particle has a magnetic drift velocity, and the speed of the magnetic drift is proportional to the kinetic energy of each particle. Hence, if the particles have high temperature, the spread of the magnetic drift velocity is large. This causes a strong cross-field diffusion of the hot electrons. In the simulation for this interchange mode, an enhanced temperature relaxation is observed between the hot and cold electrons although the theoretically predicted high frequency modes are stable. (Nogami, K.)

  6. Hot tub folliculitis

    Science.gov (United States)

    ... survives in hot tubs, especially tubs made of wood. Symptoms The first symptom of hot tub folliculitis ... may help prevent the problem. Images Hair follicle anatomy References D'Agata E. Pseudomonas aeruginosa and other ...

  7. Radioactivity and health

    International Nuclear Information System (INIS)

    Stannard, J.N.; Baalman, R.W. Jr.

    1988-01-01

    This book details the knowledge of the biological effects of ionizing radiation from the discovery of radium to about 1980. Research findings and conclusions are presented largely as the investigators saw and reported them except where the work under discussion was markedly iconoclastic and obviously wrong according to the author's comments. Findings from over 100 personal interviews and literature searches including unpublished or little-known materials are summarized. The material in the book is divided into six sections. The first section deals with naturally occurring radioactive elements. The next section covers material on man-made radioisotopes. Inhalation toxicology (radioactive dusts and particles and respirable gases) is the subject of Section 3. Section 4 deals with environmental matters - radioecology, fallout from nuclear weapons tests, transport of radionuclides, testing and standard settings, and Section 5 consists of information on laboratory and field instrumentation. The development of the therapy for exposure and of nuclear medicine is traced in the final section

  8. Method of processing radioactive wastes

    International Nuclear Information System (INIS)

    Takahashi, Toshihiko; Maruko, Morihisa; Takamura, Yoshiyuki.

    1981-01-01

    Purpose: To effectively separate radioactive claddings from the slurry of wasted ion exchange resins containing radioactive claddings. Method: Wasted ion exchange resins having radioactive claddings (fine particles of iron oxides or hydroxide adhered with radioactive cobalt) are introduced into a clad separation tank. Sulfuric acid or sodium hydroxide is introduced to the separation tank to adjust the pH value to 3 - 6. Then, sodium lauryl sulfate is added for capturing claddings and airs are blown from an air supply nozzle to generate air bubbles. The claddings are detached from the ion exchange resins and adhered to the air bubbles. The air bubbles adhered with the claddings float up to the surface of the liquid wastes and then forced out of the separation tank. (Ikeda, J.)

  9. Apparatus for filtering radioactive fluids

    International Nuclear Information System (INIS)

    Gischel, E.H.

    1975-01-01

    Apparatus is provided for filtering radioactive particles from the cooling and/or auxiliary process water of a nuclear reactor, or nuclear fuel processing plant, or other installations wherein radioactive fluid systems are known to exist. The apparatus affords disposal of the captured particles in a manner which minimizes the exposure of operating personnel to radioactivity. The apparatus comprises a housing adapted to contain a removable filter cartridge assembly, a valve normally closing the lower end of the housing, an upwardly-open shipping cask located below the valve, and an elongated operating rod assembly projecting upwardly from the filter cartridge assembly and through the upper end of the housing to enable a workman to dismount the filter cartridge assembly from its housing and to lower the filter cartridge assembly through the valve and into the cask from a remote location above the housing. (U.S.)

  10. Modelling Hot Air Balloons.

    Science.gov (United States)

    Brimicombe, M. W.

    1991-01-01

    A macroscopic way of modeling hot air balloons using a Newtonian approach is presented. Misleading examples using a car tire and the concept of hot air rising are discussed. Pressure gradient changes in the atmosphere are used to explain how hot air balloons work. (KR)

  11. Treatment of radioactive wastes

    International Nuclear Information System (INIS)

    Machida, Chuji

    1976-01-01

    Japan Atomic Energy Research Institute (JAERI) is equipped with such atomic energy facilities as a power test reactor, four research reactors, a hot laboratory, and radioisotope-producing factory. All the radioactive wastes but gas generated from these facilities are treated by the waste treatment facilities established in JAERI. The wastes carried into JAERI through Japan Radioisotope Association are also treated there. Low level water solution is treated with an evaporating apparatus, an ion-exchange apparatus, and a cohesive precipitating apparatus, while medium level solution is treated with an evaporating apparatus, and low level combustible solid is treated with an incinerating apparatus. These treated wastes and sludges are mixed with Portland cement in drum cans to solidify, and stored in a concrete pit. The correct classification and its indication as well as the proper packing for the wastes are earnestly demanded by the treatment facilities. (Kobatake, H.)

  12. Theoretical modeling of fine-particle deposition in 3-dimensional bronchial bifurcations

    International Nuclear Information System (INIS)

    Shaw, D.T.; Rajendran, N.; Liao, N.S.

    1978-01-01

    A theoretical model is developed for the prediction of the peak to average particle deposition flux in the human bronchial airways. The model involves the determination of the peak flux by a round-nose 2-dimensional bifurcation channel and the average deposition flux by a curved-tube model. The ''hot-spot'' effect for all generations in the human respiratory system is estimated. Hot spots are usually associated with the sites of bronchoconstriction or even chronic bronchitis and lung cancer. Recent studies indicate that lung cancer in smokers may be caused by the deposition of radioactive particles produced by the burning of tobacco leaves. High local concentrations of Po-210 have been measured in epithelium from bronchial bifurcations of smokes. This Po-210 is the radioactive daughter of Pb-210 which is produced from a long chain of radioactive decay starting from uranium in the fertilizer-enriched soil. It is found that the peak deposition flux is higher than the average deposition flux by a factor ranging between 5 and 30, depending on the generation number. The importance of this peak to average deposition flux ratio on consideration of environmental safety studies is discussed

  13. Radioactive Waste.

    Science.gov (United States)

    Blaylock, B. G.

    1978-01-01

    Presents a literature review of radioactive waste disposal, covering publications of 1976-77. Some of the studies included are: (1) high-level and long-lived wastes, and (2) release and burial of low-level wastes. A list of 42 references is also presented. (HM)

  14. Radioactivity measurements

    International Nuclear Information System (INIS)

    Schwach, G.

    1986-01-01

    This is an overview of radioactivity monitoring work done in the Austrian Research Centre Seibersdorf in the wake of the Chernobyl accident. It consists of air, rainwater, food and personnel monitoring. Additional services to the public are: information and development of a database and a computer code for predicting future radionuclide concentration in air, soil, water and food. (G.Q.)

  15. ESA uncovers Geminga's `hot spot'

    Science.gov (United States)

    2004-07-01

    16 July 2004 Astronomers using ESA’s X-ray observatory XMM-Newton have detected a small, bright ‘hot spot’ on the surface of the neutron star called Geminga, 500 light-years away. The hot spot is the size of a football field and is caused by the same mechanism producing Geminga’s X-ray tails. This discovery identifies the missing link between the X-ray and gamma-ray emission from Geminga. hi-res Size hi-res: 1284 kb Credits: ESA, P. Caraveo (IASF, Milan) Geminga's hot spot This figure shows the effects of charged particles accelerated in the magnetosphere of Geminga. Panel (a) shows an image taken with the EPIC instrument on board the XMM-Newton observatory. The bright tails, made of particles kicked out by Geminga’s strong magnetic field, trail the neutron star as it moves about in space. Panel (b) shows how electrically charged particles interact with Geminga’s magnetic field. For example, if electrons (blue) are kicked out by the star, positrons (in red) hit the star’s magnetic poles like in an ‘own goal’. Panel (c) illustrates the size of Geminga’s magnetic field (blue) compared to that of the star itself at the centre (purple). The magnetic field is tilted with respect to Geminga’s rotation axis (red). Panel (d) shows the magnetic poles of Geminga, where charged particles hit the surface of the star, creating a two-million degrees hot spot, a region much hotter than the surroundings. As the star spins on its rotation axis, the hot spot comes into view and then disappears, causing the periodic colour change seen by XMM-Newton. An animated version of the entire sequence can be found at: Click here for animated GIF [low resolution, animated GIF, 5536 KB] Click here for AVI [high resolution, AVI with DIVX compression, 19128 KB] hi-res Size hi-res: 371 kb Credits: ESA, P. Caraveo (IASF, Milan) Geminga's hot spot, panel (a) Panel (a) shows an image taken with the EPIC instrument on board the XMM-Newton observatory. The bright tails, made of

  16. Disposal of radioactive wastes

    International Nuclear Information System (INIS)

    Dlouhy, Z.

    1982-01-01

    This book provides information on the origin, characteristics and methods of processing of radioactive wastes, as well as the philosophy and practice of their storage and disposal. Chapters are devoted to the following topics: radioactive wastes, characteristics of radioactive wastes, processing liquid and solid radioactive wastes, processing wastes from spent fuel reprocessing, processing gaseous radioactive wastes, fixation of radioactive concentrates, solidification of high-level radioactive wastes, use of radioactive wastes as raw material, radioactive waste disposal, transport of radioactive wastes and economic problems of radioactive wastes disposal. (C.F.)

  17. Operational Strategies for Low-Level Radioactive Waste Disposal Site in Egypt - 13513

    International Nuclear Information System (INIS)

    Mohamed, Yasser T.

    2013-01-01

    The ultimate aims of treatment and conditioning is to prepare waste for disposal by ensuring that the waste will meet the waste acceptance criteria of a disposal facility. Hence the purpose of low-level waste disposal is to isolate the waste from both people and the environment. The radioactive particles in low-level waste emit the same types of radiation that everyone receives from nature. Most low-level waste fades away to natural background levels of radioactivity in months or years. Virtually all of it diminishes to natural levels in less than 300 years. In Egypt, The Hot Laboratories and Waste Management Center has been established since 1983, as a waste management facility for LLW and ILW and the disposal site licensed for preoperational in 2005. The site accepts the low level waste generated on site and off site and unwanted radioactive sealed sources with half-life less than 30 years for disposal and all types of sources for interim storage prior to the final disposal. Operational requirements at the low-level (LLRW) disposal site are listed in the National Center for Nuclear Safety and Radiation Control NCNSRC guidelines. Additional procedures are listed in the Low-Level Radioactive Waste Disposal Facility Standards Manual. The following describes the current operations at the LLRW disposal site. (authors)

  18. Remote waste handling at the Hot Fuel Examination Facility

    International Nuclear Information System (INIS)

    Vaughn, M.E.

    1982-01-01

    Radioactive solid wastes, some of which are combustible, are generated during disassembly and examination of irradiated fast-reactor fuel and material experiments at the Hot Fuel Examination Facility (HFEF). These wastes are remotely segregated and packaged in doubly contained, high-integrity, clean, retrievable waste packages for shipment to the Radioactive Waste Management Complex (RWMC) at the Idaho National Engineering Laboratory (INEL). This paper describes the equipment and techniques used to perform these operations

  19. Introduction of hot cell facility in research center Rez - Poster

    International Nuclear Information System (INIS)

    Petrickova, A.; Srba, O.; Miklos, M.; Svoboda, P.

    2015-01-01

    This poster presents the hot cell facility which is being constructed as part of the SUSEN project at the Rez research center (Czech Republic). Within this project a new complex of 10 hot cells and one semi-hot cell will be built. There will be 8 gamma hot cells and 2 alpha hot cells. In each hot cell a hermetic, removable box made of stainless steel will home different type of devices. The hot cells and semi hot cell will be equipped with devices for processing samples (cutting, welding, drilling, machining) as well as equipment for testing (sample preparation area, stress testing machine, fatigue machine, electromechanical creep machine, high frequency resonance pulsator...) and equipment for studying material microstructure (nano-indenter with nano-scratch tester and scanning electron microscope). An autoclave with water loop, installed in a cell will allow mechanical testing in control environment of water, pressure and temperature. A scheme shows the equipment of each cell. This hot laboratory will be able to cover all the process to study radioactive materials: receiving the material, the preparation of the samples, mechanical testing and microstructure observation. Our hot cells will be close to the research nuclear reactor LVR-15 and new irradiation facility (high irradiation by cobalt source) is planned to be built within the SUSEN project

  20. Effects of non-radioactive material around radioactive material on PET image quality

    International Nuclear Information System (INIS)

    Toshimitsu, Shinya; Yamane, Azusa; Hirokawa, Yutaka; Kangai, Yoshiharu

    2015-01-01

    Subcutaneous fat is a non-radioactive material surrounding the radioactive material. We developed a phantom, and examined the effect of subcutaneous fat on PET image quality. We created a cylindrical non-radioactive mimic of subcutaneous fat, placed it around a cylindrical phantom in up to three layers with each layer having a thickness of 20 mm to reproduce the obesity caused by subcutaneous fat. In the cylindrical phantom, hot spheres and cold spheres were arranged. The radioactivity concentration ratio between the hot spheres and B.G. was 4:1. The radioactivity concentration of B.G. was changed as follows : 1.33, 2.65, 4.00, and 5.30 kBq/mL. 3D-PET image were collected during 10 minutes. When the thickness of the mimicked subcutaneous fat increased from 0 mm to 60 mm, noise equivalent count decreased by 58.9-60.9% at each radioactivity concentration. On the other hand, the percentage of background variability increased 2.2-5.2 times. Mimic subcutaneous fat did not decrease the percentage contrast of the hot spheres, and did not affect the cold spheres. Subcutaneous fat decreases the noise equivalent count and increases the percentage of background variability, which degrades PET image quality. (author)

  1. Shielding experiments by the JASMIN collaboration at Fermilab (II) - Radioactivity measurement induced by secondary particles from the anti-proton production target

    Energy Technology Data Exchange (ETDEWEB)

    Yashima, Hiroshi; /Kyoto U., KURRI; Matsuda, Norihiro; Kasugai, Yoshimi; /JAEA, Ibaraki; Matsumura, Hiroshi; Iwase, Hiroshi; /KEK, Tsukuba; Kinoshita, Norikazu; /KEK, Tsukuba /Tsukuba U.; Boehnlein, David; Lauten, Gary; Leveling, Anthony; Mokhov, Nikolai; Vaziri, Kamran; /Fermilab /Shimizu, Tokyo /JAEA, Ibaraki

    2011-01-01

    The JASMIN Collaboration has performed an experiment to conduct measurements of nuclear reaction rates around the anti-proton production (Pbar) target at the Fermi National Accelerator Laboratory (FNAL). At the Pbar target station, the target, consisting an Inconel 600 cylinder, was irradiated by a 120 GeV/c proton beam from the FNAL Main Injector. The beam intensity was 3.6 x 10{sub 12} protons per second. Samples of Al, Nb, Cu, and Au were placed near the target to investigate the spatial and energy distribution of secondary particles emitted from it. After irradiation, the induced activities of the samples were measured by studying their gamma ray spectra using HPGe detectors. The production rates of 30 nuclides induced in Al, Nb, Cu, Au samples were obtained. These rates increase for samples placed in a forward (small angle) position relative to the target. The angular dependence of these reaction rates becomes larger for increasing threshold energy. These experimental results are compared with Monte Carlo calculations. The calculated results generally agree with the experimental results to within a factor of 2 to 3.

  2. Radioactivity of the JINR site environment

    International Nuclear Information System (INIS)

    Alenitskaya, S.I.; Bamblevskij, V.P.; Kargin, A.N.; Komochkov, M.M.

    1977-01-01

    The results of the study of the existing levels of enviromental radioactivity in the JINR region for 1971-1975; content of radioactive products in the grass and surface soil layer, levels of the total alpha - and beta-radioactivity of water of open reservoirs as well as the background of the gamma-radiation and charged particles are presented. The study testifies, that the operation of the JINR nuclear-physical installations does not significantly affect the radioactivity of the environment which is mainly conditioned by the products of the natural origin and the global fallouts

  3. Research on atmospheric radioactivity. [In French

    Energy Technology Data Exchange (ETDEWEB)

    Garrigue, H

    1954-01-01

    In flight at 2800 m, traces of radioactive particles were gathered, by means of a corona effect similar to that of Sella, and of long period, on April 24, 1954. At Puy-de-Dome (1465 m) after a fall of rain and snow on May 3 to 4, 1954, samples of the fallen residue showed very feeble radioactivity of period 10 days or more. This radioactivity of the airborne particles was independent of their probable natural electrical charge and mobility and was indicative of an atomic cloud.

  4. Radioactive waste management

    International Nuclear Information System (INIS)

    2013-01-01

    This eighth chapter presents the radioactive wastes and waste disposal; classification of radioactive wastes; basis requests of the radioactive waste management; conditions for a radioactive waste disposal; registers and inventories; transport of radioactive wastes from a facility to another and the radioactive waste management plan

  5. Measurement of proton capture reactions in the hot cycles: an evaluation of experimental methods

    Energy Technology Data Exchange (ETDEWEB)

    Leleux, P [Inst. de Physique Nucleaire, Univ. Catholique de Louvain, Louvain-la-Neuve (Belgium)

    1998-06-01

    In the hot cycles, most of the proton capture reactions involve radioactive nuclei in the entrance and exit channels. This paper evaluates the specific methods that were designed to measure such reactions. (orig.)

  6. Electrodeless light source provided with radioactive material

    International Nuclear Information System (INIS)

    1979-01-01

    Radioactive materials are used to assist in starting a discharge in an electrodeless light source. The radioactive emissions predispose on the inner surface of the lamp envelope loosely bound charges which thereafter assist in initiating discharge. The radioactive material can be enclosed within the lamp envelope in gaseous or non-gaseous form. Preferred materials are krypton 85 and americium 241. In addition, the radioactive material can be dispersed in the lamp envelope material or can be a pellet imbedded in the envelope material. Finally, the radioactive material can be located in the termination fixture. Sources of alpha particles, beta particles, or gamma rays are suitable. Because charges accumulate with time on the inner surface of the lamp envelope, activity levels as low as 10 -8 curie are effective as starting aids. (Auth.)

  7. Cycling the Hot CNO: A Teaching Methodology

    Science.gov (United States)

    Frost-Schenk, J. W.; Diget, C. Aa.; Bentley, M. A.; Tuff, A.

    2018-01-01

    An interactive activity to teach the hot Carbon, Nitrogen and Oxygen (HCNO) cycle is proposed. Justification for why the HCNO cycle is important is included via an example of x-ray bursts. The activity allows teaching and demonstration of half-life, nuclear isotopes, nuclear reactions, protons and a-particles, and catalytic processes. Whilst the…

  8. Radioactive waste

    International Nuclear Information System (INIS)

    Berkhout, F.

    1991-01-01

    Focusing on radioactive waste management and disposal policies in the United Kingdom, Sweden and the Federal Republic of Germany, this book gives a detailed historical account of the policy process in these three countries, and draws out the implications for theory and public policy. This comparative approach underlines how profoundly different the policy process has been in different countries. By comparing the evolution of policy in three countries, fundamental questions about the formation and resolution of technical decisions under uncertainty are clarified. The analysis of nuclear strategy, the politics of nuclear power, and the shifting emphasis of government regulation redefines the issue of radwaste management and sets it at the heat of the current debate about power, the environment and society. The combination of up-to-date technological assessment with an account of the social and political implications of radwaste management makes'Radioactive Waste'particularly useful to students of environmental studies, geography and public administration. (author)

  9. Radioactive waste

    Energy Technology Data Exchange (ETDEWEB)

    Berkhout, F

    1991-01-01

    Focusing on radioactive waste management and disposal policies in the United Kingdom, Sweden and the Federal Republic of Germany, this book gives a detailed historical account of the policy process in these three countries, and draws out the implications for theory and public policy. This comparative approach underlines how profoundly different the policy process has been in different countries. By comparing the evolution of policy in three countries, fundamental questions about the formation and resolution of technical decisions under uncertainty are clarified. The analysis of nuclear strategy, the politics of nuclear power, and the shifting emphasis of government regulation redefines the issue of radwaste management and sets it at the heat of the current debate about power, the environment and society. The combination of up-to-date technological assessment with an account of the social and political implications of radwaste management makes'Radioactive Waste'particularly useful to students of environmental studies, geography and public administration. (author).

  10. Radioactive transformations

    CERN Document Server

    Rutherford, Ernest

    2012-01-01

    Radioactive Transformations describes Ernest Rutherford's Nobel Prize-winning investigations into the mysteries of radioactive matter. In this historic work, Rutherford outlines the scientific investigations that led to and coincided with his own research--including the work of Wilhelm Rӧntgen, J. J. Thomson, and Marie Curie--and explains in detail the experiments that provided a glimpse at special relativity, quantum mechanics, and other concepts that would shape modern physics. This new edition features a comprehensive introduction by Nobel Laureate Frank Wilczek which engagingly explains how Rutherford's early research led to a better understanding of topics as diverse as the workings of the atom's nucleus, the age of our planet, and the fusion in stars.

  11. Radioactive hazards

    International Nuclear Information System (INIS)

    Gill, J.R.

    1980-01-01

    The use of radioactive substances in hospital laboratories is discussed and the attendant hazards and necessary precautions examined. The new legislation under the Health and Safety at Work Act which, it is proposed, will replace existing legal requirements in the field of health and safety at work by a system of regulations and approved codes of practice designed to maintain or improve the standards of health, safety and welfare already established, is considered with particular reference to protection against ionising radiations. (UK)

  12. Radioactive substances

    International Nuclear Information System (INIS)

    Butler, G.C.; Hyslop, C.

    1980-01-01

    The purpose of this chapter is to show how to assess the detriment resulting from the release of radioactive materials to the environment. The minimum information required for the assessments is given for seven radionuclides of interest from the point of view of environmental contamination. The seven radionuclides are tritium, krypton-85, strontium-90, iodine-131, cesium-137, radium-226 and plutonium-239. Information is given on the radiation doses and the radiation effects on man due to these radioisotopes. (AN)

  13. Radioactive wastes

    International Nuclear Information System (INIS)

    Devarakonda, M.S.; Melvin, J.M.

    1994-01-01

    This paper is part of the Annual Literature Review issue of Water Environment Research. The review attempts to provide a concise summary of important water-related environmental science and engineering literature of the past year, of which 40 separate topics are discussed. On the topic of radioactive wastes, the present paper deals with the following aspects: national programs; waste repositories; mixed wastes; waste processing and decommissioning; environmental occurrence and transport of radionuclides; and remedial actions and treatment. 178 refs

  14. Experiences in monitoring airborne radioactive contamination in JAERI

    International Nuclear Information System (INIS)

    Ikezawa, Y.; Okamoto, T.; Yabe, A.

    1980-01-01

    The following results were obtained at the Japan Atomic Energy Research Institute (JAERI) from experience in air monitoring at the hot cells for handling highly radioactive materials, the glove box containing plutonium and the cell for producing 99 Mo. (1) The ratios of activities of airborne dust to those of whole dust were of the order of 10 -2 for the semi-volatile form of 125 Sb, and 10 -3 to 10 -4 for the particulate form of 137 Cs, 144 Ce and 144 Pr, when irradiated fuels were cut in the hot cells. (2) The activity median aerodynamic diameter (AMAD) of airborne particle size distributions varied from O.4 to 15 μm with changing geometric standard deviation (sigmasub(g)) 1.7 to 7, depending on types of metallurgical treatment of fuels and on kinds of work in the cells. (3) A resuspension factor (the ratio of the concentration of airborne contamination to the surface contamination) was found to be 4x10 -8 to approximately 2x10 -7 cm -1 for plutonium oxide deposited on the floor surface. (4) The collection efficiency of the charcoal-loaded filter paper for airborne radioiodine, consisting of 60% inorganic and 40% organic iodide, was over 95% under conditions of relative humidity 40 to approximately 80% and face velocity 50 cm/sec, during the production of 99 Mo. (H.K.)

  15. Preliminary Feasibility Study on the Construction of Steel Hot Cell Facility for Precise Manipulated Examinations

    International Nuclear Information System (INIS)

    Ahn, Sangbok; Kwon, Hyungmun; Kim, Heemoon; Kim, Dosik; Min, Duckkee; Hong, Kwonpyo

    2006-01-01

    Hot laboratory is essential facility to research and develop in the nuclear industries to examine radioactive materials. The post irradiation examinations for irradiated fuels and materials should be mainly conducted in the hot cell facility to protect radiations to operators. Hot cells are divided into a concrete hot cell and a steel hot cell according to the wall materials. Usually a concrete hot cell is applied to test for high level radioactive materials like as a fuel assembly, rods, and large structure specimens, and a steel hot cell for comparatively lower level activity materials in fuel fragments, and small structural materials. A steel hot cell has many benefits in a specimen manipulation, construction and maintenance costs. In recent the test for the irradiated materials is more frequently required a small and precise manipulating examination for higher degree tests of research and developments. Unfortunately hot laboratory facilities in domestics have mainly constituted of concrete hot cells, and not ready for techniques in steel hot cells. In this paper the construction feasibility of steel hot cell facility is preliminary reviewed in the points of the status of domestic facilities, the test demand prospect and detailed plans

  16. Hot Surface Ignition

    OpenAIRE

    Tursyn, Yerbatyr; Goyal, Vikrant; Benhidjeb-Carayon, Alicia; Simmons, Richard; Meyer, Scott; Gore, Jay P.

    2015-01-01

    Undesirable hot surface ignition of flammable liquids is one of the hazards in ground and air transportation vehicles, which primarily occurs in the engine compartment. In order to evaluate the safety and sustainability of candidate replacement fuels with respect to hot surface ignition, a baseline low lead fuel (Avgas 100 LL) and four experimental unleaded aviation fuels recommended for reciprocating aviation engines were considered. In addition, hot surface ignition properties of the gas tu...

  17. Radioactive starting aids for electrodeless light sources

    International Nuclear Information System (INIS)

    Proud, J.M.; Regan, R.J.; Haugsjaa, P.O.; Baird, D.H.

    1980-01-01

    The use of radioactive sources of α particles, β particles or γ rays as aids in starting a discharge in an electrodeless light source is discussed. The advantages of siting the sources at various positions in the device are discussed. Preferred materials are 85 Kr and 241 Am. (U.K.)

  18. Remediating radium contaminated legacy sites: Advances made through machine learning in routine monitoring of “hot” particles

    Energy Technology Data Exchange (ETDEWEB)

    Varley, Adam, E-mail: a.l.varley@stir.ac.uk [Department of Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA (United Kingdom); Tyler, Andrew, E-mail: a.n.tyler@stir.ac.uk [Department of Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA (United Kingdom); Smith, Leslie, E-mail: l.s.smith@cs.stir.ac.uk [Department of Computing Science and Mathematics, University of Stirling, Stirling FK9 4LA (United Kingdom); Dale, Paul, E-mail: paul.dale@sepa.org.uk [Scottish Environmental Protection Agency, Radioactive Substances, Strathallan House, Castle Business Park, Stirling FK9 4TZ (United Kingdom); Davies, Mike, E-mail: Mike.Davies@nuvia.co.uk [Nuvia Limited, The Library, Eight Street, Harwell Oxford, Didcot, Oxfordshire OX11 0RL (United Kingdom)

    2015-07-15

    The extensive use of radium during the 20th century for industrial, military and pharmaceutical purposes has led to a large number of contaminated legacy sites across Europe and North America. Sites that pose a high risk to the general public can present expensive and long-term remediation projects. Often the most pragmatic remediation approach is through routine monitoring operating gamma-ray detectors to identify, in real-time, the signal from the most hazardous heterogeneous contamination (hot particles); thus facilitating their removal and safe disposal. However, current detection systems do not fully utilise all spectral information resulting in low detection rates and ultimately an increased risk to the human health. The aim of this study was to establish an optimised detector-algorithm combination. To achieve this, field data was collected using two handheld detectors (sodium iodide and lanthanum bromide) and a number of Monte Carlo simulated hot particles were randomly injected into the field data. This allowed for the detection rate of conventional deterministic (gross counts) and machine learning (neural networks and support vector machines) algorithms to be assessed. The results demonstrated that a Neural Network operated on a sodium iodide detector provided the best detection capability. Compared to deterministic approaches, this optimised detection system could detect a hot particle on average 10 cm deeper into the soil column or with half of the activity at the same depth. It was also found that noise presented by internal contamination restricted lanthanum bromide for this application. - Highlights: • Land contaminated with radium is hazardous to human health. • Routine monitoring permits identification and removal of radioactive hot particles. • Current alarm algorithms do not provide reliable hot particle detection. • Spectral processing using Machine Learning significantly improves detection.

  19. Remediating radium contaminated legacy sites: Advances made through machine learning in routine monitoring of “hot” particles

    International Nuclear Information System (INIS)

    Varley, Adam; Tyler, Andrew; Smith, Leslie; Dale, Paul; Davies, Mike

    2015-01-01

    The extensive use of radium during the 20th century for industrial, military and pharmaceutical purposes has led to a large number of contaminated legacy sites across Europe and North America. Sites that pose a high risk to the general public can present expensive and long-term remediation projects. Often the most pragmatic remediation approach is through routine monitoring operating gamma-ray detectors to identify, in real-time, the signal from the most hazardous heterogeneous contamination (hot particles); thus facilitating their removal and safe disposal. However, current detection systems do not fully utilise all spectral information resulting in low detection rates and ultimately an increased risk to the human health. The aim of this study was to establish an optimised detector-algorithm combination. To achieve this, field data was collected using two handheld detectors (sodium iodide and lanthanum bromide) and a number of Monte Carlo simulated hot particles were randomly injected into the field data. This allowed for the detection rate of conventional deterministic (gross counts) and machine learning (neural networks and support vector machines) algorithms to be assessed. The results demonstrated that a Neural Network operated on a sodium iodide detector provided the best detection capability. Compared to deterministic approaches, this optimised detection system could detect a hot particle on average 10 cm deeper into the soil column or with half of the activity at the same depth. It was also found that noise presented by internal contamination restricted lanthanum bromide for this application. - Highlights: • Land contaminated with radium is hazardous to human health. • Routine monitoring permits identification and removal of radioactive hot particles. • Current alarm algorithms do not provide reliable hot particle detection. • Spectral processing using Machine Learning significantly improves detection

  20. Process and device for processing radioactive wastes

    International Nuclear Information System (INIS)

    1974-01-01

    A method is described for processing liquid radioactive wastes. It includes the heating of the liquid wastes so that the contained liquids are evaporated and a practically anhydrous mass of solid particles inferior in volume to that of the wastes introduced is formed, then the transformation of the solid particles into a monolithic structure. This transformation includes the compressing of the particles and sintering or fusion. The solidifying agent is a mixture of polyethylene and paraffin wax or a styrene copolymer and a polyester resin. The device used for processing the radioactive liquid wastes is also described [fr

  1. Ultrasonic assisted hot metal powder compaction.

    Science.gov (United States)

    Abedini, Rezvan; Abdullah, Amir; Alizadeh, Yunes

    2017-09-01

    Hot pressing of metal powders is used in production of parts with similar properties to wrought materials. During hot pressing processes, particle rearrangement, plastic deformation, creep, and diffusion are of the most effective powder densification mechanisms. Applying ultrasonic vibration is thought to result in great rates of densification and therefore higher efficiency of the process is expected. This paper deals with the effects of power ultrasonic on the densification of AA1100 aluminum powder under constant applied stress. The effects of particle size and process temperature on the densification behavior are discussed. The results show that applying ultrasonic vibration leads to an improved homogeneity and a higher relative density. Also, it is found that the effect of ultrasonic vibration is greater for finer particles. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Radioactivity telemetry

    International Nuclear Information System (INIS)

    Bouras, Florent; Legrand, Bernard; Montigaud, Jean-Marie; Grandin, Marc

    1969-05-01

    The authors present an assembly which aims at radio-transmitting from mobile stations information on radioactivity. It comprises 20 mobile stations which can be located within the Cadarache Centre or outside of it within a 10 km radius, and a central station which centralises information. The report proposes a general presentation of these stations, their characteristics and principles of operation. It describes operation sequences, central station functions (call programmer, address and memory management, recording, peripherals) and its energy supply, and mobile station functions. The last part presents the installation, its start-up and exploitation, its threshold devices and its safety device

  3. Radioautographic studies of the radioactive ashes obtained from the No. 5 Fukuryu Maru

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, T; Akagi, H; Goto, H; Wakisaka, G

    1954-01-01

    Radioautographic studies have been made of the radioactive ashes obtained from the ship by use of x-ray film, radioautographic stripping plates, and plates of ..cap alpha..-emitters. The radioactivity was found not proportional to the size of the particle, and the distribution of radioactivity in each particle was not uniform.

  4. Design and management of hot-laboratories

    International Nuclear Information System (INIS)

    1976-09-01

    This document is a manual for the design and management of hot-laboratories. It is composed of three parts. The first part is devoted to the design of hot-laboratories. Items included here are; conceptual design; many regulations which must be considered at design stage; design of cave and its shielding; and the design of building, ventilation, and draining. Many examples of specific designs are presented by figures and photographs. The second part is concerned with the methods of operation management. Organizational structure, scheduling of operation, process management, and regulatory problems are discussed with some examples. Technological problems associated with the operation of a hot laboratory (e.g., manipulator, transfer machine, maintenance, and decontamination) are also discussed based on the authors' experiences. An example of the operation manual is presented for reference. The third part is devoted to the safety management and the training of personnel. The regulations by law are briefly explained. Most of this part is devoted to the problem of monitoring radio-activity. Monitoring of control areas, radio-active wastes, and personal dosage is discussed together with many other specific monitoring problems. As for training, the purpose and the present status are explained. (Aoki, K.)

  5. Hot Laboratories and Remote Handling

    International Nuclear Information System (INIS)

    Bart, G.; Blanc, J.Y.; Duwe, R.

    2003-01-01

    divided in two parts: - First, a mutual share of real examples about the 'life' in hot laboratories: waste management, decommissioning and release, safety; - Second, a presentation of tools or facilities dealing with PIE or defueling. Special radwaste management was presented by: - ISPRA, for heavy water; - IFE Kjeller, for old stored steel waste; - FZ Juelich presented an example of decommissioning and re-opening of hot laboratories; - IFE Kjeller presented a synthesis of two questionnaires sent to European Hot Laboratories on 'the fire preparedness measures in buildings with hot laboratories'; - The creep test device settled in K6 LECI Hot Cells in CEA at the Saclay site was also described; - ITU Karlsruhe/FZ Juelich presented experimental details and results from a study on a Vicker hardness test; - CEA/Valrho presented the two newest facilities of Atalante; Session 3 - Prospective Research on Materials for Future Applications comprised four presentations concerning the development of future gas cooled reactors and the materials research for nuclear fusion plants, namely: - E.H. Toscano (European Commission, ITU-Karlsruhe,Germany) who described a new facility to measure the fission product inventory; - V. Basini (CEA Cadarache, France) who presented results of HTR fuel development and innovative elaboration processes of fuel particles; - M. Roedig (FZJ, Juelich, Germany) reported on post irradiation experiments on plasma facing materials and miniaturized components for the next step fusion device ITER; - J. P. Coad (EFDA-JET, Abingdon, U.K.) who gave an overview on the tritium related technology programs at JET

  6. Environmental Radioactivity. Chapter 4

    International Nuclear Information System (INIS)

    Muhamat Omar; Ismail Sulaiman; Zalina Laili

    2015-01-01

    This chapter explains several things which consist radioactivity measurements, regular and high background radioactivity, radioactive contaminated soil and radioactivity in fertilizers, rocks, building materials, food, water, environments, sediments, flora and fauna. Besides, the natural radioactive gas concentration of radon and toron in the environment also been discussed specifically in this chapter.

  7. Surface charge accumulation of particles containing radionuclides in open air.

    Science.gov (United States)

    Kim, Yong-Ha; Yiacoumi, Sotira; Tsouris, Costas

    2015-05-01

    Radioactivity can induce charge accumulation on radioactive particles. However, electrostatic interactions caused by radioactivity are typically neglected in transport modeling of radioactive plumes because it is assumed that ionizing radiation leads to charge neutralization. The assumption that electrostatic interactions caused by radioactivity are negligible is evaluated here by examining charge accumulation and neutralization on particles containing radionuclides in open air. A charge-balance model is employed to predict charge accumulation on radioactive particles. It is shown that particles containing short-lived radionuclides can be charged with multiple elementary charges through radioactive decay. The presence of radioactive particles can significantly modify the particle charge distribution in open air and yield an asymmetric bimodal charge distribution, suggesting that strong electrostatic particle interactions may occur during short- and long-range transport of radioactive particles. Possible effects of transported radioactive particles on electrical properties of the local atmosphere are reported. The study offers insight into transport characteristics of airborne radionuclides. Results are useful in atmospheric transport modeling of radioactive plumes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Performance of HEPA filters under hot dynamic conditions

    International Nuclear Information System (INIS)

    Frankum, D.P.; Costigan, G.

    1995-01-01

    Accidents in nuclear facilities involving fires may have implications upon the ventilation systems where high efficiency particulate air (HEPA) filters are used to minimise the airborne release of radioactive or toxic particles. The Filter Development Section at Harwell Laboratory has been investigating the effect of temperature on the performance of HEPA filters under hot dynamic conditions[ 1 ] for a number of years. The test rig is capable of delivering air flows of 10001/s (at ambient conditions) at temperatures up to 500 degrees C, where measurements of the penetration and pressure drop across the filter are obtained. This paper reports the experiments on different constructions of HEPA filters; rectangular and circular. The filters were tested at an air temperature of 200 degrees C for up to 48 hours at the rated airflow to assess their performance. The penetration measurements for rectangular filters were observed to be below 0.021% after prolonged operation. In a number of cases, holes appeared along the pleat creases of circular filters although the penetration remained below 1%. The sealing gasket for these filters was noted to deform with temperature, permitting a leakage path. A prototype high strength circular filter was evaluated at temperatures of up to 400 degrees C with a penetration less than 0.65%

  9. Performance of HEPA filters under hot dynamic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Frankum, D.P.; Costigan, G. [AEA Technology, Oxfordshire (United Kingdom)

    1995-02-01

    Accidents in nuclear facilities involving fires may have implications upon the ventilation systems where high efficiency particulate air (HEPA) filters are used to minimise the airborne release of radioactive or toxic particles. The Filter Development Section at Harwell Laboratory has been investigating the effect of temperature on the performance of HEPA filters under hot dynamic conditions[{sub 1}] for a number of years. The test rig is capable of delivering air flows of 10001/s (at ambient conditions) at temperatures up to 500{degrees}C, where measurements of the penetration and pressure drop across the filter are obtained. This paper reports the experiments on different constructions of HEPA filters; rectangular and circular. The filters were tested at an air temperature of 200{degrees}C for up to 48 hours at the rated airflow to assess their performance. The penetration measurements for rectangular filters were observed to be below 0.021% after prolonged operation. In a number of cases, holes appeared along the pleat creases of circular filters although the penetration remained below 1%. The sealing gasket for these filters was noted to deform with temperature, permitting a leakage path. A prototype high strength circular filter was evaluated at temperatures of up to 400{degrees}C with a penetration less than 0.65%.

  10. New type of natural radioactivity

    International Nuclear Information System (INIS)

    Rubchenya, V.A.; Chechev, V.P.; Yavshits, S.G.

    1987-01-01

    Consideration is being given in popular form to investigations of a new type of natural radioactivity - spontaneous emission of fragments, more massive than α-particles, by heavy element nuclei, called f-decay by analogy with known α and γ decays. Some data on radioactivity, origin of the decay are presented. Possibilities of f-decay, predictions and hypotheses are discussed. The reason of late discovery of f-decay lies in low f-decay probability 10 -9 with respect to α-decay and in a certain sluggishness of settled knowledge about possible types of radioactive decay. The idea of f-decay is presented. It differs from the idea about a new type of decay as modification of asymmetric fission and contains an attempt to explain the intermediate position of f-decay between α-decay and

  11. Hot water, fresh beer, and salt

    International Nuclear Information System (INIS)

    Crawford, F.S.

    1990-01-01

    In the ''hot chocolate effect'' the best musical scales (those with the finest tone quality, largest range, and best tempo) are obtained by adding salt to a glass of hot water supersaturated with air. Good scales can also be obtained by adding salt to a glass of freshly opened beer (supersaturated with CO 2 ) provided you first (a) get rid of much of the excess CO 2 so as to produce smaller, hence slower, rising bubbles, and (b) get rid of the head of foam, which damps the standing wave and ruins the tone quality. Finally the old question, ''Do ionizing particles produce bubbles in fresh beer?'' is answered experimentally

  12. Hot water, fresh beer, and salt

    Science.gov (United States)

    Crawford, Frank S.

    1990-11-01

    In the ``hot chocolate effect'' the best musical scales (those with the finest tone quality, largest range, and best tempo) are obtained by adding salt to a glass of hot water supersaturated with air. Good scales can also be obtained by adding salt to a glass of freshly opened beer (supersaturated with CO2) provided you first (a) get rid of much of the excess CO2 so as to produce smaller, hence slower, rising bubbles, and (b) get rid of the head of foam, which damps the standing wave and ruins the tone quality. Finally the old question, ``Do ionizing particles produce bubbles in fresh beer?'' is answered experimentally.

  13. Abnormal radioactivity of the atmosphere. [In French

    Energy Technology Data Exchange (ETDEWEB)

    Garrigue, H

    1952-01-01

    Further measurements on the radioactivity of the atmosphere near Puy de Dome are tabulated. The activity in April 1952 with a mean life of 25 hrs was ascribed to the complex particles A. In June 1952 an activity with a mean life of 100 to 400 hrs was attributed to the previously observed A'' particles. The activity associated with the A'' particles was also observed in the soil and air.

  14. Radioactive waste shredding: Preliminary evaluation

    International Nuclear Information System (INIS)

    Soelberg, N.R.; Reimann, G.A.

    1994-07-01

    The critical constraints for sizing solid radioactive and mixed wastes for subsequent thermal treatment were identified via a literature review and a survey of shredding equipment vendors. The types and amounts of DOE radioactive wastes that will require treatment to reduce the waste volume, destroy hazardous organics, or immobilize radionuclides and/or hazardous metals were considered. The preliminary steps of waste receipt, inspection, and separation were included because many potential waste treatment technologies have limits on feedstream chemical content, physical composition, and particle size. Most treatment processes and shredding operations require at least some degree of feed material characterization. Preliminary cost estimates show that pretreatment costs per unit of waste can be high and can vary significantly, depending on the processing rate and desired output particle size

  15. Hot spots on Tc-99m MAA perfusion lung scan

    International Nuclear Information System (INIS)

    Lim, Seok Tae; Sohn, Myung Hee

    2001-01-01

    A 61 year-old woman underwent perfusion and inhalation lung scan for the evaluation of pulmonary thromboembolism. Tc-99m MAA perfusion lung scan showed multiple round hot spots in both lung fields. Tc-99m DTPA aerosol inhalation lung scan and chest radiography taken at the same time showed normal findings. A repeated perfusion lung scan taken 24 hours later demonstrated no abnormalities. Hot spots on perfusion lung scan can be caused by microsphere clumping due to faulty injection technique by radioactive embolization from upper extremity thrombophlebitis after injection. Focal hot spots can signify zones of atelectasis, where the hot spots probably represent a failure of hypoxic vasoconstriction. Artifactual hot spots due to microsphere clumping usually appear to be round and in peripheral location, and the lesions due to a loss of hypoxic vasoconstriction usually appear to be hot uptakes having linear borders. Although these artifactual hot spots have been well-known, we rarely encounter them. This report presents a case with artifactual hot spots due to microsphere clumping on Tc-99m MAA perfusion lung scan

  16. Cleanout and decontamination of radiochemical hot cells

    International Nuclear Information System (INIS)

    Surma, J.E.; Holton, L.K. Jr.; Katayama, Y.B.; Gose, J.E.; Haun, F.E.; Dierks, R.D.

    1990-01-01

    The Pacific Northwest Laboratory is developing and employing advanced remote and contact technologies in cleaning out and decontaminating six radiochemical hot cells at Hanford under the Department of Energy's Surplus Facilities Management Program. The program is using a series of remote and contact decontamination techniques to reduce costs and to significantly lower radiation doses to workers. Refurbishment of the cover blocks above the air lock trench reduced radiation exposure in the air lock and cleanout and decontamination of an analytical cell achieved a reduction in radioactive contamination. Nuclear Regulatory Commission-approved Type B burial boxes are also being used to reduce waste disposal costs and radiation doses. PNL is currently decommissioning its pilot-scale radioactive liquid-fed ceramic melter. Special tools have been developed and are being used to accomplish the world's first such effort. 4 refs., 5 figs

  17. Hot cell facilities for post irradiation examination

    International Nuclear Information System (INIS)

    Mishra, Prerna; Bhandekar, Anil; Pandit, K.M.; Dhotre, M.P.; Rath, B.N.; Nagaraju, P.; Dubey, J.S.; Mallik, G.K.; Singh, J.L.

    2017-01-01

    Reliable performance of nuclear fuels and critical core components has a large bearing on the economics of nuclear power and radiation safety of plant operating personnel. In view of this, Post Irradiation Examination (PIE) is periodically carried out on fuels and components to generate feedback information which is used by the designers, fabricators and the reactor operators to bring about changes for improved performance of the fuel and components. Examination of the fuel bundles has to be carried out inside hot cells due to their high radioactivity

  18. Water chemistry management during hot functional test

    International Nuclear Information System (INIS)

    Yokoyama, Jiro; Kanda, Tomio; Kagawa, Masaru

    1988-01-01

    To reduce radiation exposure in light water reactor, it is important decrease radioactive corrosion product which is a radiation source. One of the countermeasures is to improve water quality during plant trial operation to form a stable oxide film and to minimize metal release to the coolant at the beginning of commercial operation. This study reviews the optimum water quality conditions to form a chromium rich oxide film during hot functional test (HFT) that is thought to be stable under the PWR condition and reduce the release of Ni that is the source of Co-58, the main radiation source of exposure. (author)

  19. Nucleon transfer reactions with radioactive beams

    Science.gov (United States)

    Wimmer, K.

    2018-03-01

    Transfer reactions are a valuable tool to study the single-particle structure of nuclei. At radioactive beam facilities transfer reactions have to be performed in inverse kinematics. This creates a number of experimental challenges, but it also has some advantages over normal kinematics measurements. An overview of the experimental and theoretical methods for transfer reactions, especially with radioactive beams, is presented. Recent experimental results and highlights on shell evolution in exotic nuclei are discussed.

  20. Nuclear radioactive techniques applied to materials research

    CERN Document Server

    Correia, João Guilherme; Wahl, Ulrich

    2011-01-01

    In this paper we review materials characterization techniques using radioactive isotopes at the ISOLDE/CERN facility. At ISOLDE intense beams of chemically clean radioactive isotopes are provided by selective ion-sources and high-resolution isotope separators, which are coupled on-line with particle accelerators. There, new experiments are performed by an increasing number of materials researchers, which use nuclear spectroscopic techniques such as Mössbauer, Perturbed Angular Correlations (PAC), beta-NMR and Emission Channeling with short-lived isotopes not available elsewhere. Additionally, diffusion studies and traditionally non-radioactive techniques as Deep Level Transient Spectroscopy, Hall effect and Photoluminescence measurements are performed on radioactive doped samples, providing in this way the element signature upon correlation of the time dependence of the signal with the isotope transmutation half-life. Current developments, applications and perspectives of using radioactive ion beams and tech...

  1. Method of processing radioactive metal wastes

    International Nuclear Information System (INIS)

    Inoue, Yoichi; Kitagawa, Kazuo; Tsuzura, Katsuhiko.

    1980-01-01

    Purpose: To enable long and safety storage for radioactive metal wastes such as used fuel cans after the procession or used pipe, instruments and the likes polluted with various radioactive substances, by compacting them to solidify. Method: Metal wastes such as used fuel cans, which have been cut shorter and reprocessed, are pressed into generally hexagonal blocks. The block is charged in a capsule of a hexagonal cross section made of non-gas permeable materials such as soft steels, stainless steels and the likes. Then, the capsule is subjected to static hydraulic hot pressing as it is or after deaeration and sealing. While various combinations are possible for temperature, pressure and time as the conditions for the static hydraulic hot pressing, dense block with no residual gas pores can be obtained, for example, under the conditions of 900 0 C, 1000 Kg/cm 2 and one hour where the wastes are composed of zircaloy. (Kawakami, Y.)

  2. Environmental radioactivity. Measurement and monitoring

    International Nuclear Information System (INIS)

    2009-11-01

    The contribution on environmental radioactivity covers the following issues: natural and artificial radioactivity; continuous monitoring of radioactivity; monitoring authorities and measurement; radioactivity in the living environment; radioactivity in food and feeding stuff; radioactivity of game meat and wild-growing mushrooms; radioactivity in mines; radioactivity in the research center Rossendorf.

  3. Effects of fluvial processes in different order river valleys on redistribution and storage of particle-bound radioactive caesium-137 in area of significant Chernobyl fallout and impact on linked rivers with lower contamination levels

    Science.gov (United States)

    Belyaev, Vladimir; Golosov, Valentin; Shamshurina, Evgeniya; Ivanov, Maxim; Ivanova, Nadezhda; Bezukhov, Dmitry; Onda, Yuichi; Wakiyama, Yoshifumi; Evrard, Olivier

    2015-04-01

    Detailed investigations of the post-fallout fate of radionuclide contamination represent an important task in terms of environmental quality assessment. In addition, particle-bound radionuclides such as the most widespread anthropogenic isotope caesium-137 can be used as tracers for quantitative assessment of different sediment redistribution processes. In landscapes of humid plains with agriculture-dominated land use the post-fallout redistribution of caesium-137 is primarily associated with fluvial activity of various scales in cascade systems starting from soil erosion on cultivated hillslopes through gully and small dry valley network into different order perennial streams and rivers. Our investigations in the so-called Plavsk hotspot (area of very high Chernobyl caesium-137 contamination within the Plava River basin, Tula Region, Central European Russia) has been continuing for more than 15 years by now, while the time passed since the Chernobyl disaster and associated radioactive fallout (1986) is almost 29 years. Detailed information on the fluvial sediment and associated caesium-137 redistribution has been obtained for case study sites of different size from individual cultivated slopes and small catchments of different size (2-180 km2) to the entire Plava River basin scale (1856 km2). It has been shown that most of the contaminated sediment over the time passed since the fallout has remained stored within the small dry valleys of the 1-4 Hortonian order and local reservoirs (>70%), while only about 5% reached the 5-6 order valleys (main tributaries of the Plava River) and storage of the Plava floodplain itself represents as low as 0.3% of the basin-scale total sediment production from eroded cultivated hillslopes. Nevertheless, it has been shown that contaminated sediment yield from the Plava River basin exerts significant influence on less polluted downstream-linked river system. Recent progress of the investigations involved sampling of 7 detailed depth

  4. Hot Weather Tips

    Science.gov (United States)

    ... the person plenty of water and fruit or vegetable juice even if they say they’re not thirsty. No alcohol, coffee or tea. Seek medical help if you suspect dehydration. Light meals: Avoid hot, heavy meals and don’ ...

  5. China's 'Hot Money' Problems

    National Research Council Canada - National Science Library

    Martin, Michael F; Morrison, Wayne M

    2008-01-01

    .... The recent large inflow of financial capital into China, commonly referred to as "hot money," has led some economists to warn that such flows may have a destabilizing effect on China's economy...

  6. Preparation of radioactive colloidal gold 198Au

    International Nuclear Information System (INIS)

    Cammarosano, S.A.

    1979-01-01

    The preparation with simple equipment of radioactive colloidal gold of particle size about approximately 300 A from seed colloid stabilized by gelatine is described. Some physico-chemical parameters which can affect the process of formation of these colloidal particles are analysed; particle size has been meassured with an electron microscope. The colloid stability has been studied as a function of dilution, age and pH. Nucleation and growth of radioactive colloidal gold have been studied using spectrophotometry. Absorption spectra of the two ones are presented and compared. Quality control of the production process is verified through measurement of parameters, such as radioactive and radiochemical purity and biological distribution in laboratorial animals. This distribution was evalusted for rats injected endovenously with the gold colloidal solution.(Author) [pt

  7. Conditional probability of intense rainfall producing high ground concentrations from radioactive plumes

    International Nuclear Information System (INIS)

    Wayland, J.R.

    1977-03-01

    The overlap of the expanding plume of radioactive material from a hypothetical nuclear accident with rainstorms over dense population areas is considered. The conditional probability of the occurrence of hot spots from intense cellular rainfall is presented

  8. Radioactive materials production

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    The Radiochemical Processing Plant (RPP) at ORNL has served as the national repository and distribution center for 233 U for > 20 years. Several hundred kilograms of uranium, containing approximately 90 to 98% 233 U, are stored there in the form of metal, oxides, and nitrate solutions. All of these uranium materials contain small, but significant, concentrations of 232 U, ranging from 2 to 225 ppm. Most of the radioactivity associated with the 233 U comes from the decay daughters of 232 U (74-year half-life). The 252 Cf Industrial Sales/Loan Program involves loans of 252 Cf neutron sources to agencies of the US Government and sales of 252 Cf as the bulk oxide and as palladium-californium alloy pellets and wires. The program has been operated since 1968 in temporary facilities at the Savannah River Laboratory (SRL). The obsolete hot-cell facilities at SRL are now being decommissioned, and the program activities are being transferred to ORNL's Californium Facility in Bldg. 7930, which is managed by the staff of the Transuranium Processing Plant

  9. Disposal of radioactive wastes

    International Nuclear Information System (INIS)

    Blomeke, J.O.

    1979-01-01

    Radioactive waste management and disposal requirements options available are discussed. The possibility of beneficial utilization of radioactive wastes is covered. Methods of interim storage of transuranium wastes are listed. Methods of shipment of low-level and high-level radioactive wastes are presented. Various methods of radioactive waste disposal are discussed

  10. Transport of radioactive substances

    International Nuclear Information System (INIS)

    2014-12-01

    The report on the transport of radioactive substances covers the following topics: facts on radioactive materials transport, safety of the transport of radioactive substances, legal regulations and guidelines: a multiform but consistent system, transport of nuclear fuels, safety during the transport of nuclear fuel, future transport of spent fuel elements and high-level radioactive wastes in Germany.

  11. Remote Robotic Cleaning System for Contaminated Hot-Cell Floor

    International Nuclear Information System (INIS)

    Kim, Ki Ho; Park, Jang Jin; Yang, Myung S.; Kwon, Hyo Kjo

    2005-01-01

    The M6 hot-cell of the Irradiated Material Examination Facility at the Korea Atomic Energy Research Institute (KAERI) has been contaminated with spent fuel debris and other radioactive waste due to the DUPIC nuclear fuel development processes. As the hot-cell is active, direct human workers' access, even with protection, to the in-cell is not possible because of the nature of the high radiation level of the spent PWR fuel. A remote robotic cleaning system has been developed for use in a highly radioactive environment of the M6 hot-cell. The remote robotic cleaning system was designed to completely eliminate human interaction with hazardous radioactive contaminants. This robotic cleaning system was also designed to remove contaminants or contaminated smears placed or fixed on the floor of the M6 hot-cell by mopping it in a remote manner. The environmental, functional and mechanical design considerations, control system and capabilities of the developed remote robotic cleaning system are presented

  12. Small-scale hot facility for reprocessing and alpha research

    International Nuclear Information System (INIS)

    Abdel-Rassoul, A.A.

    1976-01-01

    The experimental hot facility at Inchas is planned for research activities related to the decontamination of radioactive wastes, analytical chemistry of alpha emitters and chemical treatment of spent UO 2 -Mg fuel samples. The design concept permits safe handling of source materials with radioactivity levels up to 10000Ci. The laboratory includes a reception area, process hall, a number of research laboratories and other facilities for chemical and physical analysis, nuclear measurements and health physics control. The radioactive waste management plant allows for control and decontamination of intermediate- and low-level laboratory effluents. Fixation of radioactive residues will be carried out in the sludge immobilization plant. High-level fission-product waste liquors are subject to preconcentration and transformation to a glassy matrix before ultimate storage. (author)

  13. Radioactive waste management

    International Nuclear Information System (INIS)

    Kawakami, Yutaka

    2008-01-01

    Radioactive waste generated from utilization of radioisotopes and each step of the nuclear fuel cycle and decommissioning of nuclear facilities are presented. On the safe management of radioactive waste management, international safety standards are established such as ''The Principles of Radioactive Waste Management (IAEA)'' and T he Joint Convention on the Safety of Radioactive Waste Management . Basic steps of radioactive waste management consist of treatment, conditioning and disposal. Disposal is the final step of radioactive waste management and its safety is confirmed by safety assessment in the licensing process. Safety assessment means evaluation of radiation dose rate caused by radioactive materials contained in disposed radioactive waste. The results of the safety assessment are compared with dose limits. The key issues of radioactive waste disposal are establishment of long term national strategies and regulations for safe management of radioactive waste, siting of repository, continuity of management activities and financial bases for long term, and security of human resources. (Author)

  14. Hot-Gas Filter Ash Characterization Project

    Energy Technology Data Exchange (ETDEWEB)

    Swanson, M.L.; Hurley, J.P.; Dockter, B.A.; O`Keefe, C.A.

    1997-07-01

    Large-scale hot-gas filter testing over the past 10 years has revealed numerous cases of cake buildup on filter elements that has been difficult, if not impossible, to remove. At times, the cake can blind or bridge between candle filters, leading to filter failure. Physical factors, including particle-size distribution, particle shape, the aerodynamics of deposition, and system temperature, contribute to the difficulty in removing the cake, but chemical factors such as surface composition and gas-solid reactions also play roles in helping to bond the ash to the filters or to itself. This project is designed to perform the research necessary to determine the fuel-, sorbent-, and operations-related conditions that lead to blinding or bridging of hot-gas particle filters. The objectives of the project are threefold: (1) Determine the mechanisms by which a difficult-to-clean ash is formed and how it bridges hot-gas filters (2) Develop a method to determine the rate of bridging based on analyses of the feed coal and sorbent, filter properties, and system operating conditions and (3) Suggest and test ways to prevent filter bridging.

  15. Radioactive pollution

    International Nuclear Information System (INIS)

    Pohl, R.O.

    1976-01-01

    The widely published claims that the public health effects resulting from routine emissions are between 0.01 and 0.1 serious health effects per gigawattyear, and hence are at least a thousand times smaller than those resulting from air pollution by the burning of coal, cannot be true, for two reasons. The authors of these claims have ignored at least two of the more important isotopes, radon-222 and carbon-14, which are presently released to the environment, and thus contribute greatly to the health impact of nuclear energy. The health effects calculated in the earlier work cover only those which occur during the year in which the energy is generated. This means, figuratively speaking, that the authors have confused an annual installment payment with the full cost. This is unacceptable. The contribution to the health impact of nuclear energy arising from the single isotopic species radon-222 emanating from the mill tailings is estimated to 400 lung cancer deaths/GW(e)y, larger even than the most pessimistic estimates of the health impact of energy from coal through atmospheric pollution. We have no assurance that other long-lived isotopes do not contribute comparable amounts to the health impact of nuclear energy. The discussion of the health impact of radon-222 raises the fundamental moral question--how far into the future our responsibility extends. If such a long-termresponsibility is rejected, then we must at least try to predict the environmental buildup of radioactive pollutants, in order to avoid unacceptable and irreversible levels of radiation dose rate. The potential health consequences from long-lived radioisotopes seem to have been largely ignored so far, and should be explored in detail

  16. Technical specifications of variable speed motors for negative pressure control in hot cell area

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seon Duk; Bang, H. S.; Cho, W. K

    2002-01-01

    Hot cells are the facilities for handling the high radioactive materials and various R and D activities are performed using hot cells. Therefore the control of air flow in hot cell area is very important technology and it is started with the variable speed motor(VSM) controlling the air handling system in that area. This report describes various technical aspects of VS motors and will be useful for understanding the practical technologies of VS motors and also for optimization of the negative pressure controls in hot cell area.

  17. Method for producing ceramic particles and agglomerates

    Science.gov (United States)

    Phillips, Jonathan; Gleiman, Seth S.; Chen, Chun-Ku

    2001-01-01

    A method for generating spherical and irregularly shaped dense particles of ceramic oxides having a controlled particle size and particle size distribution. An aerosol containing precursor particles of oxide ceramics is directed into a plasma. As the particles flow through the hot zone of the plasma, they melt, collide, and join to form larger particles. If these larger particles remain in the hot zone, they continue melting and acquire a spherical shape that is retained after they exit the hot zone, cool down, and solidify. If they exit the hot zone before melting completely, their irregular shape persists and agglomerates are produced. The size and size distribution of the dense product particles can be controlled by adjusting several parameters, the most important in the case of powder precursors appears to be the density of powder in the aerosol stream that enters the plasma hot zone. This suggests that particle collision rate is responsible for determining ultimate size of the resulting sphere or agglomerate. Other parameters, particularly the gas flow rates and the microwave power, are also adjusted to control the particle size distribution.

  18. 燃气喷射推力矢量喷管气固两相流数值模拟%Numerical simulation of gas-particle flow in hot gas injection thrust vector nozzle

    Institute of Scientific and Technical Information of China (English)

    刘辉; 邢玉明

    2013-01-01

    利用Euler-Lagrangian方法模拟了固体火箭发动机燃气喷射推力矢量喷管气固两相内流场,研究了固体颗粒对喷管推力矢量性能的影响,气相采用Roe格式和MUSCL (monotone upstream-centred schemes for conservation laws)插值进行空间2阶迎风离散,时间推进采用隐式时间格式;固体颗粒相采用随机轨道模型计算颗粒轨迹,并与气相进行双向耦合.结果表明:固体颗粒的存在使弓形激波强度增强,但降低了推力矢量角和推力系数;颗粒质量分数相同时,粒径越大,推力矢量角和推力系数越大;颗粒直径相同时,颗粒质量分数越大,推力矢量角和推力系数越小.%The gas-particle inner flowfield of gas injection thrust vector nozzle in solid rocket engine was simulated using Euler-Lagrangian method, and the effect of solid particle on thrust vector performance was studied. The Roe scheme and monotone upstream-centred schemes for conservation laws (MUSCL) method were used for secondary-order accuracy spatial discretization for gas phase, and the implicit scheme was employed for time marching. The stochastic trajectory model and two-way coupled with gas phase were employed for particle phase. The results indicate that the strength of bow shock is increased due to solid particles, but the thrust vector angle and thrust coefficient are decreased; thrust vector angle and thrust coefficient increase with the particle diameter increasing under the same mass fraction of particle condition; thrust vector angle and thrust coefficient decrease with the mass fraction of particle increasing under the same particle diameter condition.

  19. Energy flux of hot atoms

    International Nuclear Information System (INIS)

    Wotzak, G.P.; Kostin, M.D.

    1976-01-01

    The process in which hot atoms collide with thermal atoms of a gas, transfer kinetic energy to them, and produce additional hot atoms is investigated. A stochastic method is used to obtain numerical results for the spatial and time dependent energy flux of hot atoms in a gas. The results indicate that in hot atom systems a front followed by an intense energy flux of hot atoms may develop

  20. HotRegion: a database of predicted hot spot clusters.

    Science.gov (United States)

    Cukuroglu, Engin; Gursoy, Attila; Keskin, Ozlem

    2012-01-01

    Hot spots are energetically important residues at protein interfaces and they are not randomly distributed across the interface but rather clustered. These clustered hot spots form hot regions. Hot regions are important for the stability of protein complexes, as well as providing specificity to binding sites. We propose a database called HotRegion, which provides the hot region information of the interfaces by using predicted hot spot residues, and structural properties of these interface residues such as pair potentials of interface residues, accessible surface area (ASA) and relative ASA values of interface residues of both monomer and complex forms of proteins. Also, the 3D visualization of the interface and interactions among hot spot residues are provided. HotRegion is accessible at http://prism.ccbb.ku.edu.tr/hotregion.

  1. Tackling Tuwaitha's radioactive ruins

    International Nuclear Information System (INIS)

    2006-01-01

    Full text: Some 1000 Iraqi men, women and children in a village near the former Tuwaitha nuclear site are living inside an area contaminated by radioactive residues and ruins. A project to clean-up the site, and other contaminated facilities in Iraq, was kick-started earlier this year at IAEA headquarters. Inhabitants of the Ishtar village, based within the Tuwaitha site boundary, some 20 kilometres south of Baghdad, are living in an area where levels of radiation are known to be higher than normal and prolonged exposure could prove risky over time. US authorities have supplied the IAEA with photographs of the Tuwaitha reactor that show crumbling facades and interiors of rubble, spray-painted with warnings like 'radioactive' and 'HOT'. (See Photo Essay). Once at the heart of Iraq's nuclear programme, the Tuwaitha complex was inspected and largely dismantled during IAEA-led weapons inspections in the 1990s and subsequently bombed in the 2003 war. It is one of a number of sites in the country identified as needing decommissioning or remediation where radioactive material was used or waste are buried. The Iraqi Government has requested the IAEA's assistance to prepare plans and programmes to decommission contaminated facilities in the country. The project's groundwork was set at an IAEA meeting in Vienna in February 2006, attended by the Iraqi Minister for Science and Technology, representatives from sixteen countries, including the US, and the European Commission. 'This is a huge task, one that could take many years,' says Mr. Dennis Reisenweaver, the IAEA safety expert in charge of the effort. Among the first steps is to identify, cordon off, and prioritise contaminated areas that pose the most risk to the public. Some of the challenges facing the clean-up effort include determining now unknown locations where contaminated equipment and materials might be buried, and recovering lost records about the contents of radioactive materials stored in waste containers

  2. Kinetics of chemical reactions initiated by hot atoms

    International Nuclear Information System (INIS)

    Firsova, L.P.

    1977-01-01

    Modern ideas about kinetics of chemical reactions of hot atoms are generalized. The main points of the phenomenological theories (''kinetic theory'' of Wolfgang-Estrup hot reactions and the theory of ''reactions integral probability'' of Porter) are given. Physico-chemical models of elastic and non-elastic collisions are considered which are used in solving Boltzmann integro-differential equations and stochastic equations in the Porter theory. The principal formulas are given describing probabilities or yields of chemical reactions, initiated with hot atoms, depending on the distribution functions of hot particles with respect to energy. Briefly described are the techniques and the results of applying the phenomenological theories for interpretation of the experimental data obtained during nuclear reactions with hot atoms, photochemical investigations, etc. 96 references are given

  3. Study of fine particles (PM{sub 2.5}) during the dry-hot time in the Toluca city; Estudio de las particulas finas (PM{sub 2.5}) durante la epoca seca-caliente en la ciudad de Toluca

    Energy Technology Data Exchange (ETDEWEB)

    Rosendo G, V. [ITT, 50000 Toluca (Mexico); Aldape U, F. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: vero_rosen2108@yahoo.com.mx

    2007-07-01

    The first obtained results of the analysis of the fine fraction particulate material (PM{sub 2.5}) samples collected in the Toluca City are presented. The samples analyzed are part of a more extensive campaign that contemplates the low project the one which one carries out this work and that it integrates three climatic times (dry-hot, of rains and dry-cold time) with the purpose of investigating the events of contamination in one complete year. The obtained results correspond to the dry-hot time and its include mainly the database starting from which the temporal variation graphs were obtained, the correlations among elements and the enrichment factor, as well as a multiple correlation analysis. Additionally the gravimetry was measured. Its are not observed significant episodes, however, it was found an element of the traces order, little common in other atmospheric studies as it is arsenic. From the gravimetry it was deduced that the air quality standard of fine particle, it does not violate. (Author)

  4. Set of devices for producing radioactive 60Co-sources

    International Nuclear Information System (INIS)

    Eichhorn, P.; Tobisch, F.

    1982-01-01

    A set of devices for producing radioactive 60 Co-sources was developed. A single source has a radioactivity of 445x10 10 GBq. It consists of a double envelope of stainless steel filled with a mixture of small pieces of cobalt and stainless steel wire. The diameter of a source is 11 mm; the length 80 mm. Cobalt wires of different radioactivity with a length of about 110 mm and 0,8 mm diameter are the raw material. The set is located in a hot cell. Construction, functions and operation of the set are described in detail. (author)

  5. Management of Disused Radioactive Sealed Sources in Egypt - 13512

    International Nuclear Information System (INIS)

    Mohamed, Y.T.; Hasan, M.A.; Lasheen, Y.F.

    2013-01-01

    The future safe development of nuclear energy and progressive increasing use of sealed sources in medicine, research, industry and other fields in Egypt depends on the safe and secure management of disused radioactive sealed sources. In the past years have determined the necessity to formulate and apply the integrated management program for radioactive sealed sources to assure harmless and ecological rational management of disused sealed sources in Egypt. The waste management system in Egypt comprises operational and regulatory capabilities. Both of these activities are performed under legislations. The Hot Laboratories and Waste Management Center HLWMC, is considered as a centralized radioactive waste management facility in Egypt by law 7/2010. (authors)

  6. Method of treatment in a system passing radioactive material

    Energy Technology Data Exchange (ETDEWEB)

    Kamiya, K; Kinoshita, M; Asakura, Y

    1976-05-14

    A method to ensure the safety of the reactor and reduce radiation exposure dose by preventing oxygen hydrogen reaction of the reactor off-gas and accumulation of the radioactive material is described. Substances which are accumulated in an off-gas duct and are likely to capture radioactive material (for instance Pd catalyst falling from a recombiner) is changed into a stable material (for instance, PdI/sub 2/) which is hot likely to capture radioactive material through reaction with a stabilizer (for instance, I/sub 2/, Cl/sub 2/, HCl, etc.). This stabilized material is washed off the atomic power plant system.

  7. Functional design criteria radioactive liquid waste line replacement, Project W-087. Revision 3

    International Nuclear Information System (INIS)

    McVey, C.B.

    1994-01-01

    This document provides the functional design criteria for the 222-S Laboratory radioactive waste drain piping and transfer pipeline replacement. The project will replace the radioactive waste drain piping from the hot cells in 222-S to the 219-S Waste Handling Facility and provide a new waste transfer route from 219-S to the 244-S Catch Station in Tank Farms

  8. Shield wall evaluation of hot cell facility for advanced spent fuel conditioning process

    International Nuclear Information System (INIS)

    Cho, I. J.; Kuk, D. H.; Ko, J. H.; Jung, W. M.; Yoo, G. S.; Lee, E. P.; Park, S. W.

    2002-01-01

    The future hot cell is located in the Irradiated Material Experiment Facility (IMEF) at the Korea Atomic Energy Research Institute (KAERI). It is β-γ type hot cell that was constructed on the base floor in IMEF building for irradiated material testing. And this hot cell will be used for carrying out the Advanced spent fuel Conditioning Process (ACP). The radiation shielding capability of hot cell should be sufficient to meet the radiation dose requirements in the related regulations. Because the radioactive sources of ACP are expected to be higher than radioactive sources of IMEF design criteria, the future hot cell in current status is unsatisfactory to hot test of ACP. So the shielding analysis of the future hot cell is performed to evaluate shielding ability of concrete shield wall. The shielding analysis included (a) identification of ACP source term; (b) photon source spectrum; (c) shielding analysis by QADS and MCNP-4C; and (d) enhancement of concrete shield wall. In this research, dose rates are obtained according to ACP source, geometry and hot cell shield wall thickness. And the evaluation and reinforcement thickness of the shield wall about future hot cell are concluded

  9. Mesoscale meteorological model based on radioactive explosion cloud simulation

    International Nuclear Information System (INIS)

    Zheng Yi; Zhang Yan; Ying Chuntong

    2008-01-01

    In order to simulate nuclear explosion and dirty bomb radioactive cloud movement and concentration distribution, mesoscale meteorological model RAMS was used. Particles-size, size-active distribution and gravitational fallout in the cloud were considered. The results show that the model can simulate the 'mushroom' clouds of explosion. Three-dimension fluid field and radioactive concentration field were received. (authors)

  10. Decommissioning of the Risoe Hot Cell facility

    International Nuclear Information System (INIS)

    Carlsen, H.

    1991-02-01

    The Hot Cell facility at Risoe has been in active use since 1964. During the years several types of nuclear fuels have been handled and examined: test reactor fuel pins from the Danish reactor DR3, the Norwegian Halden reactor, etc; power reactor fuel pins from several foreign reactors, including plutonium enriched pins; HTGR fuel from the Dragon reactor. All kinds of physical and chemical non-destructive and destructive post irradiation examinations have been performed. Besides, different radiotherapy sources have been produced, mainly cobalt sources. The general object of the decommissioning programme for the Hot Cell facility was to obtain a safe condition for the total building that does not require the special safety provisions. The hot cell building will be usable for other purposes after decommissioning. The facilicy comprised six concrete cells, lead cells, glove boxes, a shielded unit for temporary storage of waste, frogman area, decontamination areas, workshops, various installations of importance for safe operation of the plant, offices, etc. The tasks comprised e.g. removal of all irradiated fuel items, removal of other radioactive items, removal of contaminated equipment, and decontamination of all the cells and rooms. The goal was to decontaminate all the concrete cells to a degree where no loose contamination exists in the cells, and where the radiation level is so low, that total removal of the cell structures can be done at any time in the future without significant dose commitments. (AB)

  11. Natural atmospheric radioactivity

    International Nuclear Information System (INIS)

    Renoux, A.

    1986-01-01

    After having summed up the different old or new units, used in radioactivity and radioprotection, the origins of atmospheric radioactivity are reported. Next the authors deal with the air content in radon, thoron and their radioactive descendants, insisting on the variations of the radon air content and on the radioactive balance between radon and its descendants. Then a few notions concerning the natural radioactive aerosol are developed: electric charge state, granulometric distribution. The possible effects of natural atmospheric radioactivity on man are studied with a distinction between inner irradiation and outer irradiation, an average assessment is shown. Finally the important problem of radon in inhabitations is approached [fr

  12. Solidification of radioactive waste effluents

    International Nuclear Information System (INIS)

    Mergan, L.M.; Cordier, J.-P.

    1981-01-01

    A process and apparatus for solidifying radioactive waste liquid containing dissolved and/or suspended solids is disclosed. The process includes chemically treating for pH adjustment and precipitation of solids, concentrating solids with a thin-film evaporator to provide liquid concentrate containing about 50% solids, and drying the concentrate with a heated mixing apparatus. The heated mixing apparatus includes a heated wall and working means for shearing dried concentrate from internal surfaces and subdividing dry concentrate into dry, powdery particles. The working means includes a rotor and helical means for positively advancing the concentrate and resulting dry particles from inlet to outlet of the mixing apparatus. The dry particles may also be encapsulated in a matrix material. Entrained particles in the vapor stream from the evaporator and mixer are removed in an integral particle separator and the vapor is subsequently condensed and may be recycled upstream of the thin-film evaporator. A section of the mixer may be used for mixing dry particles with the matrix material in a continuous drying and mixing sequence. A section of the mixer also may be used for mixing the treating chemical with the waste liquid

  13. Particle Pollution

    Science.gov (United States)

    ... Your Health Particle Pollution Public Health Issues Particle Pollution Recommend on Facebook Tweet Share Compartir Particle pollution — ... see them in the air. Where does particle pollution come from? Particle pollution can come from two ...

  14. Simple description of cluster radioactivity

    International Nuclear Information System (INIS)

    Tavares, O.A.P.; Medeiros, E.L.

    2012-05-01

    The partial half-life of radioactive decay of nuclei by the emission of fragments heavier than the alpha particle, such as the emission of carbon, oxygen, neon, magnesium, and silicon isotopes from translead nuclei (known as cluster radioactivity), is re-evaluated in the framework of a semiempirical, one-parameter model based on the quantum mechanical tunneling mechanism through a potential barrier where the Coulomb, centrifugal, and overlapping contributions to the barrier are considered within the spherical nucleus approximation. This treatment has shown not only very adequate to t all the existing half-life data, but also to give more reliable half-life predictions for new, yet unmeasured cases of spontaneous emission of massive nuclear fragments both from heavy and intermediate-mass parent nuclei as well. (author)

  15. Utilizing hot electrons

    Energy Technology Data Exchange (ETDEWEB)

    Nozik, Arthur J.

    2018-03-01

    In current solar cells, any photon energy exceeding the semiconductor bandgap is lost before being collected, limiting the cell performance. Hot carrier solar cells could avoid these losses. Now, a detailed experimental study and analysis shows that this strategy could lead to an improvement of the photoconversion efficiency in practice.

  16. Radioactive waste management in West Germany

    Energy Technology Data Exchange (ETDEWEB)

    Krause, H [Kernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.)

    1978-01-01

    The technologies developed in West Germany for radioactive waste management are widely reviewed. The first topic in this review paper is the disposal of low- and middle-level radioactive liquid wastes. Almost all these liquid wastes are evaporated, and the typical decontamination factor attained is 10/sup 4/ -- 10/sup 6/. The second topic is the solidification of residuals. Short explanation is given to bituminization and some new processes. The third topic is high-level liquid wastes. Degradation of glass quality due to various radiation is discussed. Embedding of small glass particles containing radioactive wastes into metal is also explained. Disposals of low-level solid wastes and the special wastes produced from reprocessing and mixed oxide fuel fabrication are explained. Final disposal of radioactive wastes in halite is discussed as the last topic. Many photographs are used to illustrate the industrial or experimental use of those management methods.

  17. Method of concentrating radioactive liquid waste

    International Nuclear Information System (INIS)

    Yasumura, Keijiro

    1990-01-01

    Radioactive liquid wastes generated from nuclear power facilities are caused to flow into a vessel incorporated with first hydrophobic porous membranes. Then, the radioactive liquid wastes are passed through the first hydrophobic porous membranes under an elevated or reduced pressure to remove fine particles contained in the liquid wastes. The radioactive liquid wastes passed through the first membranes are stored in a temporary store a vessel and steams generated under heating are passed through the second hydrophobic porous membranes and then cooled and concentrated as condensates. In this case, the first and the second hydrophobic porous membranes have a property of passing steams but not water and, for example, are made of tetrafluoroethylen resin type thin membranes. Accordingly, since the fine particles can be removed by the first hydrophobic porous membranes, lowering of the concentration rate due to the deposition of solid contents to the membranes upon concentration can be prevented. (I.S.)

  18. Distribution of radioactive minerals in a granite

    Energy Technology Data Exchange (ETDEWEB)

    Coppens, R

    1949-04-04

    The study, by means of a photographic plate, of the radioactivity of a Brittany granite, both of a pulverized sample and of a polished sample, has resulted in a complete determination of the radioactivity present. The ratio of the concentration of Th to that of U i.e., C/sub Th/C/sub U/, was determined as approximately 2.8 using the relationship between the concentration of these elements and the number of ..beta.. particles in a particular range which were detected. Using this ratio and measuring the average number of ..cap alpha.. particles emitted/cm/sup 2//sec, the average activities were found to correspond to concentrations of the order of 10/sup -5/ of both metals. The lack of uniformity in the distribution of the radioactivity within the crystal is noted.

  19. Scanning electron microscope facility for examination of radioactive materials

    International Nuclear Information System (INIS)

    Gibson, J.R.; Braski, D.N.

    1985-02-01

    An AMRAY model 1200B scanning electron microscope was modified to permit remote examination of radioactive specimens. Features of the modification include pneumatic vibration isolation of the column, motorized stage controls, improvements for monitoring vacuum, and a system for changing filaments without entering the hot cell

  20. Radioactive wast management in Sweden

    International Nuclear Information System (INIS)

    Sivintsev, Yu.V.

    1985-01-01

    A system under development and partially realized of NPP radioactive waste management in Sweden up to spent-fuel disposal in underground storage is described. The system implies that the spent fuel after unloading from a reactor is stored at the NPP in water shielded tanks. Then fuel assemblies (FA) are transforted by a special ship, being operated since 1982, to the CLAB central storage. In CLAB water pools lacated in underground granite openings fuel assemblies will be stored for 40 years. CLAB is suggested to be put in operation in 1985. At the next stage FA are transported from CLAB to the canning set-up (located on the ground above the under ground disposal). Hot isostatic pressing is used for hermetization as a method allowing to make monolithic copper containers with a storage time of about 1 mln years. Sealed copper containers will be put into a burial ground sited in crystal rocks

  1. IEN Low-level-radioactive waste Management

    International Nuclear Information System (INIS)

    Rocha, A.C.S. da; Pina, J.L.S.; Silva, S. da; Silva, J.J.G.

    1986-01-01

    The control, treatment and disposal of the low-level radioactive waste produced in the units of IEN-CNEN, in Brazil are presented, in details. These wastes are generated from a particle accelerator (CV-28 cyclotron), radiochemistry laboratories and a nuclear research reactor (Argonaut type). (Author) [pt

  2. System for disposing of radioactive waste

    International Nuclear Information System (INIS)

    Gablin, K.A.; Hansen, L.J.

    1980-01-01

    A system is disclosed for disposing of radioactive mixed liquid and particulate waste material from nuclear reactors by solidifying the liquid components into a free standing hardened mass with a syrup of partially polymerized particles of urea formaldehyde in water and a liquid curing agent

  3. Air conditioning systems to clean radioactive air

    International Nuclear Information System (INIS)

    Ganz, G.

    1987-01-01

    The author reports a study by the Institutes fuer Klimatechnik and Umweltschutz Giessen that shows that air conditioning systems not only make the atmosphere more comfortable, they also extract dust particles. This cleaning action is also valid for radioactively contaminated air. (G.T.H./Auth.)

  4. Radioactivity and geophysics

    International Nuclear Information System (INIS)

    Radvanyi, P.

    1992-01-01

    The paper recalls a few steps of the introduction of radioactivity in geophysics and astrophysics: contribution of radioelements to energy balance of the Earth, age of the Earth based on radioactive disintegration and the discovery of cosmic radiations

  5. Radioactive Waste Management Strategy

    International Nuclear Information System (INIS)

    2002-01-01

    This strategy defines methods and means how collect, transport and bury radioactive waste safely. It includes low level radiation waste and high level radiation waste. In the strategy are foreseen main principles and ways of storage radioactive waste

  6. Radioactivity in consumer products

    Energy Technology Data Exchange (ETDEWEB)

    Moghissi, A.A.; Paras, P.; Carter, M.W.; Barker, R.F. (eds.)

    1978-08-01

    Papers presented at the conference dealt with regulations and standards; general and biological risks; radioluminous materials; mining, agricultural, and construction materials containing radioactivity; and various products containing radioactive sources.

  7. Radioactivity of bone cement

    International Nuclear Information System (INIS)

    Scherer, M.A.; Winkler, R.; Ascherl, R.; Lenz, E.

    1993-01-01

    A total of 14 samples of different types of bone cement from five different manufacturers were examined for their radioactivity. Each of the investigated bone cements showed a low radioactivity level, i.e. between [de

  8. Immersed radioactive wastes

    International Nuclear Information System (INIS)

    2017-03-01

    This document presents a brief overview of immersed radioactive wastes worldwide: historical aspects, geographical localization, type of wastes (liquid, solid), radiological activity of immersed radioactive wastes in the NE Atlantic Ocean, immersion sites and monitoring

  9. Radioactive waste vitrification offgas analysis proposal

    International Nuclear Information System (INIS)

    Nelson, C.W.; Morrey, E.V.

    1993-11-01

    Further validation of the Hanford Waste Vitrification Plant (HWVP) feed simulants will be performed by analyzing offgases during crucible melting of actual waste glasses and simulants. The existing method of vitrifying radioactive laboratory-scale samples will be modified to allow offgas analysis during preparation of glass for product testing. The analysis equipment will include two gas chromatographs (GC) with thermal conductivity detectors (TCD) and one NO/NO x analyzer. This equipment is part of the radioactive formating offgas system. The system will provide real-time analysis of H 2 , O 2 , N 2 , NO, N 2 O, NO 2 , CO, CO 2 , H 2 O, and SO 2 . As with the prior melting method, the product glass will be compatible with durability testing, i.e., Product Consistency Test (PCT) and Material Characterization Center (MCC-1), and crystallinity analysis. Procedures have been included to ensure glass homogeneity and quenching. The radioactive glass will be adaptable to Fe +2 /ΣFe measurement procedures because the atmosphere above the melt can be controlled. The 325 A-hot cell facility is being established as the permanent location for radioactive offgas analysis during formating, and can be easily adapted to crucible melt tests. The total costs necessary to set up and perform offgas measurements on the first radioactive core sample is estimated at $115K. Costs for repeating the test on each additional core sample are estimated to be $60K. The schedule allows for performing the test on the next available core sample

  10. Transport of radioactive wastes

    International Nuclear Information System (INIS)

    Stuller, C.

    2003-01-01

    In this article author describes the system of transport and processing of radioactive wastes from nuclear power of Slovenske elektrarne, plc. It is realized the assurance of transport of liquid and solid radioactive wastes to processing links from places of their formation, or of preliminary storage and consistent transports of treated radioactive wastes fixed in cement matrix of fibre-concrete container into Rebublic storage of radioactive wastes in Mochovce

  11. Polarized secondary radioactive beams

    International Nuclear Information System (INIS)

    Zaika, N.I.

    1992-01-01

    Three methods of polarized radioactive nuclei beam production: a) a method nuclear interaction of the non-polarized or polarized charged projectiles with target nuclei; b) a method of polarization of stopped reaction radioactive products in a special polarized ion source with than following acceleration; c) a polarization of radioactive nuclei circulating in a storage ring are considered. Possible life times of the radioactive ions for these methods are determined. General schemes of the polarization method realizations and depolarization problems are discussed

  12. Management of radioactive waste

    International Nuclear Information System (INIS)

    Neerdael, B.; Marivoet, J.; Put, M.; Van Iseghem, P.; Volckaert, G.; Wacquier, W.

    1998-09-01

    The document gives an overview of of different aspects of radioactive waste management in Belgium. The document discusses the radioactive waste inventory in Belgium, the treatment and conditioning of radioactive waste as well as activities related to the characterisation of different waste forms. A separate chapter is dedicated to research and development regarding deep geological disposal of radioactive waste. In the Belgian waste management programme, particular emphasis is on studies for disposal in clay. Main results of these studies are highlighted and discussed

  13. Focus on radioactivity

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, M

    1989-01-01

    Written for children, this book looks at the nature of radioactive materials, how they were discovered, what they are used for and how they affect the environment around us. The emphasis is on the benefits of radioactive materials, particularly in nuclear power stations, in medical diagnostics and radiotherapy, in industry and in agriculture. Nuclear fission and fusion are explained, how radioactive materials are handled and naturally occurring radioactivity are included. (UK).

  14. Radioactive waste management

    International Nuclear Information System (INIS)

    Balek, V.

    1994-01-01

    This booklet is a publication by International Atomic Energy Agency for general awareness of citizens and policy-makers to clarify their concept of nuclear wastes. In a very simple way it tells what is radioactivity, radiations and radioactive wastes. It further hints on various medial and industrial uses of radiations. It discusses about different types of radioactive wastes and radioactive waste management. Status of nuclear power plants in Central and Eastern European countries are also discussed

  15. Radioactive consumer products

    International Nuclear Information System (INIS)

    Sato, Otomaru

    1981-01-01

    Present situation of utilizing the radioactive consumer products and exposure dose were reviewed with published data. Practically, consumer products are divided into three categories, (1) radioactive nuclides intentionally incorporated into radioluminous dye, ionization chambers for smoke detector, eliminator of static electricity, and glow lamp (2) natural radioactive nuclides contained in false teeth, porcelain, glass, and gas mantle (3) natural radioactive nuclides accumulated as industrial waste at the consumption of coal, petroleum, and natural gas or in fertilizer and materials for construction. (Nakanishi, T.)

  16. Aspects of radioactive waste management

    International Nuclear Information System (INIS)

    Cutoiu, Dan

    2003-01-01

    The origin and types of radioactive waste, the objective and the fundamental principles of radioactive waste management and the classification of radioactive waste are presented. Problems of the radioactive waste management are analyzed. (authors)

  17. Astrophysical r- and rp-processes, and radioactive nuclear beams

    International Nuclear Information System (INIS)

    Boyd, Richard N.

    1998-01-01

    The modern description of the r-process follows naturally from α-rich freezeout, thought to occur in the hot neutrino wind just beyond the nascent neutron star in a type II supernova. Initially, all pre-existing nuclei are reduced to α-particles and neutrons. As the environment cools, nuclei up to about mass 90 to 100 u are synthesized, in nuclear statistical equilibrium, in about 1 s. In the next few seconds, the remaining neutrons are captured to form the r-process progenitors, which then decay to the r-process nuclides. The rp-process occurs in a high-temperature H-rich environment. It is one of the processes that synthesize the p-process nuclei, the most neutron-poor nuclei in the periodic table. It is thought to occur during the explosion of a C-O white dwarf in a type Ia supernova or in a binary system during accretion onto a white dwarf or a neutron star. It appears to be capable of forming the p-nuclei up to about mass 90 u. Both processes pass through nuclei that are far from stability. Thus, their description requires the masses, half-lives, decay modes, and structure of these nuclei. The next generation of radioactive beam facilities promises to allow the study of many such nuclei. (author)

  18. Hot Deformation Behavior of Hot-Extruded AA7175 Through Hot Torsion Tests.

    Science.gov (United States)

    Lee, Se-Yeon; Jung, Taek-Kyun; Son, Hyeon-Woo; Kim, Sang-Wook; Son, Kwang-Tae; Choi, Ho-Joon; Oh, Sang-Ho; Lee, Ji-Woon; Hyun, Soong-Keun

    2018-03-01

    The hot deformation behavior of hot-extruded AA7175 was investigated with flow curves and processing maps through hot torsion tests. The flow curves and the deformed microstructures revealed that dynamic recrystallization (DRX) occurred in the hot-extruded AA7175 during hot working. The failure strain was highest at medium temperature. This was mainly influenced by the dynamic precipitation of fine rod-shaped MgZn2. The processing map determined the optimal deformation condition for the alloy during hot working.

  19. Effect of external hot EGR dilution on combustion, performance and particulate emissions of a GDI engine

    International Nuclear Information System (INIS)

    Xie, Fangxi; Hong, Wei; Su, Yan; Zhang, Miaomiao; Jiang, Beiping

    2017-01-01

    Highlights: • Effect of hot EGR on combustion and PN emission is investigated on a GDI engine. • Appropriate addition of hot EGR can reduce fuel consumption, NO_x and PN emission. • Relationship between BSFC and emissions of hot EGR is better than cooled EGR. • Condition with low-medium speeds and medium loads are more suitable for hot EGR. - Abstract: In this paper, an experimental investigation about the influence of hot EGR addition on the engine combustion, performance and particulate number emission was conducted at a spark-ignition gasoline direct injection (GDI) engine. Meanwhile, the different effects between cooled and hot EGR addition methods were compared and the variations of fuel consumption and particle number emissions under six engine operating conditions with different speeds and loads were analyzed. The research result indicated that increasing hot EGR ratio properly with adjustment of ignition timing could effectively improve the relationship among brake-specific fuel consumption (BSFC), NO_x and particle number emissions. When hot EGR ratio increased to 20%, not only BSFC but also the NO_x and particle number emissions were reduced, which were about 7%, 87% and 36% respectively. Compared with cooled EGR, the flame development and propagation speeds were accelerated, and cycle-by-cycle combustion variation decreased with hot EGR. Meanwhile, using hot EGR made the engine realize a better relationship among fuel consumption, NO_x and particle number emissions. The biggest improvements of BSFC, NO_x and particle number emissions were obtained at low-medium speed and medium load engine conditions by hot EGR addition method. While engine speed increased and load decreased, the improvement of engine fuel consumption and emission reduced with hot EGR method.

  20. Transport of radioactive materials

    International Nuclear Information System (INIS)

    2013-01-01

    This ninth chapter presents de CNEN-NE--5.01 norm 'Transport of radioactive material'; the specifications of the radioactive materials for transport; the tests of the packages; the requests for controlling the transport and the responsibilities during the transport of radioactive material

  1. Radioactivity in the environment

    International Nuclear Information System (INIS)

    2011-01-01

    Illustrated by drawings, this publication briefly describes radioactive exposure modalities (external or internal irradiation), the ways they are measured and assessed (doses, units), the different natural radioactivity origins, the different radioactivity origins related to human activity, the share of each origin in population exposures

  2. Software Simulation of Hot Tearing

    DEFF Research Database (Denmark)

    Andersen, S.; Hansen, P.N.; Hattel, Jesper Henri

    1999-01-01

    The brittleness of a solidifying alloy in a temperature range near the solidus temperature has been recognised since the fifties as the mechanism responsible for hot tearing. Due to this brittlenes, the metal will crack under even small amounts of strain in that temperature range. We see these hot...... tears in castings close to hot centres, where the level of strain is often too high.Although the hot tearing mechanism is well understood, until now it has been difficult to do much to reduce the hot tearing tendency in a casting. In the seventies, good hot tearing criteria were developed by considering...... the solidification rate and the strain rate of the hot tear prone areas. But, until recently it was only possible to simulate the solidification rate, so that the criteria could not be used effectively.Today, with new software developments, it is possible to also simulate the strain rate in the hot tear prone areas...

  3. The feasibility study of hot cell decontamination by the PFC spray method

    International Nuclear Information System (INIS)

    Hui-Jun Won; Chong-Hun Jung; Jei-Kwon Moon

    2008-01-01

    The characteristics of per-fluorocarbon compounds (PFC) are colorless, non-toxic, easily vaporized and nonflammable. Also, some of them are liquids of a high density, low surface tension, low latent heat and low specific heat. These particular chemical and physical properties of fluoro-organic compounds permit their use in very different fields such as electronics, medicine, tribology, nuclear and material science. The Sonatol process was developed under a contract with the DOE. The Sonatol process uses an ultrasonic agitation in a PFC solution that contains a fluorinated surfactant to remove radioactive particles from surfaces. Filtering the suspended particles allows the solutions to be reused indefinitely. They applied the Sonatol process to the decontamination of a heterogeneous legacy Pu-238 waste that exhibited an excessive hydrogen gas generation, which prevents a transportation of such a waste to a Waste Isolation Pilot Plant. Korea Atomic Energy Research Institute (KAERI) is developing dry decontamination technologies applicable to a decontamination of a highly radioactive area loosely contaminated with radioactive particles. This contamination has occurred as a result of an examination of a post-irradiated material or the development of the DUPIC process. The dry decontamination technologies developed are the carbon dioxide pellet spray method and the PFC spray method. As a part of the project, PFC ultrasonic decontamination technology was developed in 2004. The PFC spray decontamination method which is based on the test results of the PFC ultrasonic method has been under development since 2005. The developed PFC spray decontamination equipment consists of four modules (spray, collection, filtration and distillation). Vacuum cup of the collection module gathers the contaminated PFC solution, then the solution is moved to the filtration module and it is recycled. After a multiple recycling of the spent PFC solution, it is purified in the distillation

  4. Hot subluminous star: HDE 283048

    International Nuclear Information System (INIS)

    Laget, M.; Vuillemin, A.; Parsons, S.B.; Henize, K.G.; Wray, J.D.

    1978-01-01

    The star HDE 283048, located at α = 3/sup h/50/sup m/.3, delta = +25 0 36', shows a strong ultraviolet continuum. Ground-based observations indicate a hot-dominated composite spectrum. Several lines of evidence suggest that the hot component is a hot subdwarf. 2 figures

  5. Pulmonary distribution of [sup 99m]Tc-technegas; A comparative study of radioactive inert gases

    Energy Technology Data Exchange (ETDEWEB)

    Kawakami, Kenji; Shimada, Takao; Mori, Yutaka; Goto, Eisuke; Hirasawa, Yukinori [Jikei Univ., Tokyo (Japan). School of Medicine; Tominaga, Shigeru

    1992-10-01

    Technetium 99m-technegas ([sup 99m]Tc-gas), which consists of fine particles, is produced in carbon crucibles burned at 2500degC. In this study, the particle size of [sup 99m]Tc-gas was measured and the pulmonary distribution of [sup 99m]Tc-gas was assessed in 28 patients with various pulmonary diseases. Most particles were 5[approx]30 nm in diameter as determined by electron microscopy. In a clinical study, about 37 MBq of [sup 99m]Tc-gas was inhaled three times during deep breathing in a sitting position. In a comparative study with radioactive inert gases ([sup 133]Xe, [sup 81m]Kr), [sup 99m]Tc-gas showed a similar distribution to the inert gas in most patients, although some with obstructive disease showed hot spots in the lung fields. In patients with severe obstructive change, marked deposits of [sup 99m]Tc-gas was noted in the central airways, but [sup 99m]Tc-gas penetrated to the peripheral lung field. This result suggests that [sup 99m]Tc-gas can be used to evaluate ventilatory function even in patients with chronic obstructive pulmonary diseases. (author).

  6. Surface deposition from radioactive plumes

    International Nuclear Information System (INIS)

    Garland, J.A.

    1980-01-01

    Accidents involving nuclear plants may release radioactive particles and gases to the atmosphere. Dry deposition of particles has been investigated mainly in the laboratory and a general understanding of the transfer mechanisms has been established. However there is apparently a substantial discrepancy between the few field observations of dry deposition of particles and laboratory measurements, particularly for 0.1 - 1 μm particles for which laboratory work shows very small deposition rates. In addition there are few estimates of deposition rates for forest and some other kinds of terrain. The most important gas in the context of a nuclear accident is I-131 and the behaviour of this gas at grass surfaces has received much attention. However smaller quantities of other gases and vapours may be released and the surface absorption of these species may require further investigation. In addition there is little knowledge of the behaviour of gases over many types of surface. The rate of deposition of particles and gases is influenced by many parameters including wind speed and the temperature stratification of the lower atmosphere. Conditions which give poor atmospheric dispersion usually give lower deposition velocities. Transfer to man depends on the availability of deposited materials on crops and grass. A wide range of isotopes including iodine and several metallic fission products are lost with a half life for residence on grass ranging from a few days to a few tens days, depending on climatic conditions

  7. Giant resonances in hot rotating nuclei

    International Nuclear Information System (INIS)

    Ring, P.

    1992-01-01

    Present theoretical descriptions of the giant resonances in hot rotating nuclei are reviewed. Mean field theory is used as a basis for the description of the hot compound states. Starting from the static solution at finite temperature and with fixed angular momentum small amplitude collective vibrations are calculated in the frame work of finite temperature random phase approximation for quasi-particles. The effect of pairing at low temperatures as well as the effect of rotations on the position of the resonance maxima are investigated. Microscopic and phenomenological descriptions of the damping mechanisms are reviewed. In particular it turns out that fluctuations play an important role in understanding of the behaviour of the width as a function of the temperature. Motional narrowing is critically discussed. (author). 99 refs., 5 figs

  8. Method for hot pressing beryllium oxide articles

    Science.gov (United States)

    Ballard, Ambrose H.; Godfrey, Jr., Thomas G.; Mowery, Erb H.

    1988-01-01

    The hot pressing of beryllium oxide powder into high density compacts with little or no density gradients is achieved by employing a homogeneous blend of beryllium oxide powder with a lithium oxide sintering agent. The lithium oxide sintering agent is uniformly dispersed throughout the beryllium oxide powder by mixing lithium hydroxide in an aqueous solution with beryllium oxide powder. The lithium hydroxide is converted in situ to lithium carbonate by contacting or flooding the beryllium oxide-lithium hydroxide blend with a stream of carbon dioxide. The lithium carbonate is converted to lithium oxide while remaining fixed to the beryllium oxide particles during the hot pressing step to assure uniform density throughout the compact.

  9. Design Report for ACP Hot Cell Rear Door

    Energy Technology Data Exchange (ETDEWEB)

    Ku, J. H.; Kwon, K. C.; Choung, W. M.; Cho, I. J.; Kook, D. H.; Lee, W. K.; You, G. S.; Lee, E. P.; Park, S. W

    2005-12-15

    A hot-cell facility was constructed at the IMEF building for the demonstrate ACP process. ACP hot-cell consists of process cell and maintenance cell, and each cell has rear door. Since this facility was constructed at basement floor, all process materials, equipment and radioactive materials are take in and out through the rear door. Also, this door can be an access route of workers for the maintenance works. Therefore ACP hot-cell rear doors must maintain the radiation shielding, sealing, mechanical and structural safety. This report presents design criteria, design contents of each part and driving part. It was confirmed that the rear doors sufficiently maintain the safety through the structural analysis and shielding analysis. Also, it was confirmed that the rear doors were constructed as designed by the gamma scanning test after the installation.

  10. Design Report for ACP Hot Cell Rear Door

    International Nuclear Information System (INIS)

    Ku, J. H.; Kwon, K. C.; Choung, W. M.; Cho, I. J.; Kook, D. H.; Lee, W. K.; You, G. S.; Lee, E. P.; Park, S. W.

    2005-12-01

    A hot-cell facility was constructed at the IMEF building for the demonstrate ACP process. ACP hot-cell consists of process cell and maintenance cell, and each cell has rear door. Since this facility was constructed at basement floor, all process materials, equipment and radioactive materials are take in and out through the rear door. Also, this door can be an access route of workers for the maintenance works. Therefore ACP hot-cell rear doors must maintain the radiation shielding, sealing, mechanical and structural safety. This report presents design criteria, design contents of each part and driving part. It was confirmed that the rear doors sufficiently maintain the safety through the structural analysis and shielding analysis. Also, it was confirmed that the rear doors were constructed as designed by the gamma scanning test after the installation

  11. Treating radioactive effluent

    International Nuclear Information System (INIS)

    Kirkham, I.A.

    1981-01-01

    In the treatment of radioactive effluent it is known to produce a floc being a suspension of precipitates carrying radioactive species in a mother liquor containing dissolved non-radioactive salts. It is also known and accepted practice to encapsulate the floc in a solid matrix by treatment with bitumen, cement and the like. In the present invention the floc is washed with water prior to encapsulation in the solid matrix whereby to displace the mother liquor containing the dissolved non-radioactive salts. This serves to reduce the final amount of solidified radioactive waste with consequent advantages in the storage and disposal thereof. (author)

  12. Securing radioactive sources through a proper management

    International Nuclear Information System (INIS)

    Mourao, Rogerio Pimenta

    2009-01-01

    The safety and security of radioactive sources have become a hot issue for the nuclear community in the last two decades. The Goiania accident in Brazil and the September 11th attack alerted governments and nuclear agencies around the world to the vulnerability of the thousands of disused radioactive sources ill-stored or misplaced in a myriad of ways, especially in countries with less developed infra-structure. Once the threat of environmental contamination or malevolent use of these sources became clear, the International Atomic Energy Agency and the American Government spawned initiatives to reduce this risk, basically stimulating the proper conditioning of the sources and, whenever possible, seeking their repatriation to the countries of origin. Since 1996 Brazil has been participating actively in this effort, having carried out hands-on operations to condition old radium sources in Latin American and Caribbean countries and also repatriated its own neutron sources to the United States. A new operation is presently being organized: the reconditioning of the high activity sources contained in teletherapy units stored in the country using a mobile hot cell developed in South Africa. Also an agreement is being negotiated between the US National Nuclear Security Agency and the Brazilian CNEN to repatriate hundreds of radioactive gauges presently stored at CNEN's source storage buildings. (author)

  13. System for disposing of radioactive waste

    International Nuclear Information System (INIS)

    Gablin, K.A.; Hansen, L.J.

    1979-01-01

    A system is described for disposing of radioactive waste material from nuclear reactors by solidifying the liquid components to produce an encapsulated mass adapted for disposal by burial. The method contemplates mixing of radioactive waste materials, with or without contained solids, with a setting agent capable of solidifying the waste liquids into a free standing hardened mass, placing the resulting liquid mixture in a container with a proportionate amount of a curing agent to effect solidification under controlled conditions, and thereafter burying the container and contained solidified mixture. The setting agent is a water-extendable polymer consisting of a suspension of partially polymerized particles of urea formaldehyde in water, and the curing agent is sodium bisulfate. Methods are disclosed for dewatering slurry-like mixtures of liquid and particulate radioactive waste materials, such as spent ion exchange resin beads, and for effecting desired distribution of non-liquid radioactive materials in the central area of the container prior to solidification, so that the surrounding mass of lower specific radioactivity acts as a partial shield against higher radioactivity of the non-liquid radioactive materials. The methods also provide for addition of non-radioactive filler materials to dilute the mixture and lower the overall radioactivity of the hardened mixture to desired Lowest Specific Activity counts. An inhibiting agent is added to the liquid mixture to adjust the solidification time, and provision is made for adding additional amounts of setting agent and curing agent to take up any free water and further encapsulate the hardened material within the container. 30 claims

  14. System for disposing of radioactive waste

    International Nuclear Information System (INIS)

    Gablin, K.A.; Hansen, L.J.

    1977-01-01

    A system is described for disposing of radioactive waste material from nuclear reactors by solidifying the liquid components to produce an encapsulated mass adapted for disposal by burial. The method contemplates mixing of radioactive waste materials, with or without contained solids, with a setting agent capable of solidifying the waste liquids into a free standing hardened mass, placing the resulting liquid mixture in a container with a proportionate amount of a curing agent to effect solidification under controlled conditions, and thereafter burying the container and contained solidified mixture. The setting agent is a water-extendable polymer consisting of a suspension of partially polymerized particles of urea formaldehyde in water, and the curing agent is sodium bisulfate. Methods are disclosed for dewatering slurry-like mixtures of liquid and particulate radioactive waste materials, such as spent ion exchange resin beads, and for effecting desired distribution of non-liquid radioactive materials in the central area of the container prior to solidification, so that the surrounding mass of lower specific radioactivity acts as a partial shield against higher radioactivity of the non-liquid radioactive materials. The methods also provide for addition of non-radioactive filler materials to dilute the mixture and lower the overall radioactivity of the hardened mixture to desired Lowest Specific Activity counts. An inhibiting agent is added to the liquid mixture to adjust the solidification time, and provision is made for adding additional amounts of setting agent and curing agent to take up any free water and further encapsulate the hardened material within the container

  15. Hot chocolate effect

    International Nuclear Information System (INIS)

    Crawford, F.S.

    1982-01-01

    The ''hot chocolate effect'' was investigated quantitatively, using water. If a tall glass cylinder is filled nearly completely with water and tapped on the bottom with a softened mallet one can detect the lowest longitudinal mode of the water column, for which the height of the water column is one-quarter wavelength. If the cylinder is rapidly filled with hot tap water containing dissolved air the pitch of that mode may descend by nearly three octaves during the first few seconds as the air comes out of solution and forms bubbles. Then the pitch gradually rises as the bubbles float to the top. A simple theoretical expression for the pitch ratio is derived and compared with experiment. The agreement is good to within the 10% accuracy of the experiments

  16. Hot water reticulation

    Energy Technology Data Exchange (ETDEWEB)

    Fellows, S. K.

    1977-10-15

    Hot water reticulation (district heating) is an established method of energy supply within cities in many countries. It is based on the fact that heat can often be obtained cheaply in bulk, and that the resultant savings can, in suitable circumstances, justify the investment in a reticulation network of insulated pipes to distribute the heat to many consumers in the form of hot water or occasionally steam. The heat can be used by domestic, commercial, and industrial consumers for space heating and water heating, and by industries for process heat. The costs of supplying domestic consumers can be determined by considering an average residential area, but industrial and commercial consumers are so varied in their requirements that every proposal must be treated independently. Fixed costs, variable costs, total costs, and demand and resource constraints are discussed.

  17. The hot chocolate effect

    Science.gov (United States)

    Crawford, Frank S.

    1982-05-01

    The ''hot chocolate effect'' was investigated quantitatively, using water. If a tall glass cylinder is filled nearly completely with water and tapped on the bottom with a softened mallet one can detect the lowest longitudinal mode of the water column, for which the height of the water column is one-quarter wavelength. If the cylinder is rapidly filled with hot tap water containing dissolved air the pitch of that mode may descend by nearly three octaves during the first few seconds as the air comes out of solution and forms bubbles. Then the pitch gradually rises as the bubbles float to the top. A simple theoretical expression for the pitch ratio is derived and compared with experiment. The agreement is good to within the 10% accuracy of the experiments.

  18. Hot air balloon engine

    Energy Technology Data Exchange (ETDEWEB)

    Edmonds, Ian [Solartran Pty Ltd, 12 Lentara Street, Kenmore, Brisbane 4069 (Australia)

    2009-04-15

    This paper describes a solar powered reciprocating engine based on the use of a tethered hot air balloon fuelled by hot air from a glazed collector. The basic theory of the balloon engine is derived and used to predict the performance of engines in the 10 kW to 1 MW range. The engine can operate over several thousand metres altitude with thermal efficiencies higher than 5%. The engine thermal efficiency compares favorably with the efficiency of other engines, such as solar updraft towers, that also utilize the atmospheric temperature gradient but are limited by technical constraints to operate over a much lower altitude range. The increased efficiency allows the use of smaller area glazed collectors. Preliminary cost estimates suggest a lower $/W installation cost than equivalent power output tower engines. (author)

  19. The hot bench scale plant Ester for the vitrification of high level wastes

    International Nuclear Information System (INIS)

    Nannicini, R.; Strazzer, A.; Cantale, C; Donato, A.; Grossi, G.

    1985-01-01

    In this paper the hot bench-scale plant ESTER for the vitrification of the high-level radioactive wastes is described, and the main results of the first radioactive campaign are reported. The ESTER plant, which is placed in the ADECO-ESSOR hot cells of the C.C.R.-EURATOM-ISPRA, has been built and is operated by the ENEA, Departement of Fuel Cycle. It began operating with real radioactive wastes about 1 year ago, solidifying a total of 12 Ci of fission products into 2,02 Kg of borosilicate glass, corresponding to 757 ml of glass. During the vitrification many samples of liquid and gaseous streams have been taken and analyzed. A radioactivity balance in the plant has been calculated, as well as a mass balance of nitrates and of the 137 Cs and 106 Ru volatized in the process

  20. Determination of U and Pu in highly radioactive solutions. Application to the analysis of fuel reprocessing solutions

    International Nuclear Information System (INIS)

    Denis, Alphonse

    Various devices intended for the X-ray fluorescence analysis of U and Pu in radioactive solutions were developed in a hot cell: a device for sample deposition and preparation; a measurement unit. The problems investigated are described [fr

  1. The ''hot'' patella

    International Nuclear Information System (INIS)

    Kipper, M.S.; Alazraki, N.P.; Feiglin, D.H.

    1982-01-01

    Increased patellar uptake on bone scans is seen quite commonly but the possible or probable etiologies of this finding have not been previously well described. A review of 100 consecutive bone scans showed that the incidence of bilateral ''hot'' patellae is 15%. Identified etiologies include osteoarthritic degenerative disease (35%), fracture, possible metastatic disease, bursitis, Paget's disease, and osteomyelitis. The value of careful history, physical examination, and radiographs is stressed

  2. Hot nuclei and fragmentation

    International Nuclear Information System (INIS)

    Guerreau, D.

    1993-01-01

    A review is made of the present status concerning the production of nuclei above 5 MeV temperature. Considerable progress has been made recently on the understanding of the formation and the fate of such hot nuclei. It appears that the nucleus seems more stable against temperature than predicted by static calculations. However, the occurrence of multifragment production at high excitation energies is now well established. The various experimental features of the fragmentation process are discussed. (author) 59 refs., 12 figs

  3. Solar Hot Water Heater

    Science.gov (United States)

    1978-01-01

    The solar panels pictured below, mounted on a Moscow, Idaho home, are part of a domestic hot water heating system capable of providing up to 100 percent of home or small business hot water needs. Produced by Lennox Industries Inc., Marshalltown, Iowa, the panels are commercial versions of a collector co-developed by NASA. In an effort to conserve energy, NASA has installed solar collectors at a number of its own facilities and is conducting research to develop the most efficient systems. Lewis Research Center teamed with Honeywell Inc., Minneapolis, Minnesota to develop the flat plate collector shown. Key to the collector's efficiency is black chrome coating on the plate developed for use on spacecraft solar cells, the coating prevents sun heat from "reradiating," or escaping outward. The design proved the most effective heat absorber among 23 different types of collectors evaluated in a Lewis test program. The Lennox solar domestic hot water heating system has three main components: the array of collectors, a "solar module" (blue unit pictured) and a conventional water heater. A fluid-ethylene glycol and water-is circulated through the collectors to absorb solar heat. The fluid is then piped to a double-walled jacket around a water tank within the solar module.

  4. Avoiding Carbon Bed Hot Spots in Thermal Process Off-Gas Systems

    International Nuclear Information System (INIS)

    Soelberg, Nick; Enneking, Joe

    2011-01-01

    Mercury has had various uses in nuclear fuel reprocessing and other nuclear processes, and so is often present in radioactive and mixed (radioactive and hazardous) wastes. Test programs performed in recent years have shown that mercury in off-gas streams from processes that treat radioactive wastes can be controlled using fixed beds of activated sulfur-impregnated carbon, to levels low enough to comply with air emission regulations such as the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards. Carbon bed hot spots or fires have occurred several times during these tests, and also during a remediation of tanks that contained mixed waste. Hot spots occur when localized areas in a carbon bed become heated to temperatures where oxidation occurs. This heating typically occurs due to heat of absorption of gas species onto the carbon, but it can also be caused through external means such as external heaters used to heat the carbon bed vessel. Hot spots, if not promptly mitigated, can grow into bed fires. Carbon bed hot spots and fires must be avoided in processes that treat radioactive and mixed waste. Hot spots are detected by (a) monitoring in-bed and bed outlet gas temperatures, and (b) more important, monitoring of bed outlet gas CO concentrations. Hot spots are mitigated by (a) designing for appropriate in-bed gas velocity, for avoiding gas flow maldistribution, and for sufficient but not excessive bed depth, (b) appropriate monitoring and control of gas and bed temperatures and compositions, and (c) prompt implementation of corrective actions if bed hot spots are detected. Corrective actions must be implemented quickly if bed hot spots are detected, using a graded approach and sequence starting with corrective actions that are simple, quick, cause the least impact to the process, and are easiest to recover from.

  5. New bathing therapy in Japanese hot springs using radiation from radon

    International Nuclear Information System (INIS)

    Sugimori, Kenji; Okajima, Maiko; Oowada, Mizuno; Koyama, Yoshihisa; Shozugawa, Katsumi; Matsuo, Motoyuki

    2015-01-01

    Japanese-style bathing is an important part of the traditional culture of Japan, and most Japanese people love hot springs. Many kinds of hot springs exist all over Japan and are often a major factor when considering where to go for travel, relaxation and rest. However, other countries, especially in Europe, also use hot springs for medical treatments such as balneo therapy, hydrokinetic therapy, fango therapy and inhalation therapy. Some hot springs in Japan are located on radioactive springs. Five typical radioactive spring areas can be found in Tamagawa (Akita Pref.), Murasugi (Niigata Pref.), Masutomi (Yamanashi Pref.), Misasa (Tottori Pref.), and Sekigane (Tottori Pref.). While hot springs in Japan are mainly used for bathing, these radioactive springs are also used for bedrock bathing and/or inhalation therapy. In Italy, Fango therapy is a medical treatment conducted under a medical doctor's super vision with peloids maturated with hot spring water called 'Fango'. Japanese style Fango, named Biofango R , has already been made by using natural hot springs that have been modified with Italian Fango. Medical evaluation of test subjects has shown good results after treatment with Fango therapy. An important point in Fango therapy is how to make satisfactory maturated peloids. For this purpose, an experiment was conducted at Masutomi hot spring to confirm the possibility of using radioactive spring water to make maturated peloids. The basement material for the peloids used for this experiment was made from bentonite mixed with original rock from the Masutomi hot spring area consisting of crushed basalt and granite that have a fine amount of radioactivity. These peloids were circulated through hot spring water for two weeks to a month and then used for treatment. The medical data showed that therapy using this method resulted in greater improvement in 'test subjects' body functions compared with the data from previous observations. This

  6. Concept of an immersive assistance system with augmented reality for the support of manual activities in radioactive production environments

    International Nuclear Information System (INIS)

    Eursch, Andreas A.

    2010-01-01

    The thesis on an immersive assistance system concept with augmented reality for the support of manual activities in radioactive production environments covers the following topics: analysis of the situation: production and use of radioactive materials, problem analysis of the work in the production facilities, necessity of manual activities, automation, prediction in hot cells; status of research and development; assistance system concept, immersive camera system; augmented reality support in hot cells; economic evaluation and generalization.

  7. Safety evaluation report of hot cell facilities for demonstration of advanced spent fuel conditioning process

    International Nuclear Information System (INIS)

    You, Gil Sung; Choung, W. M.; Ku, J. H.; Cho, I. J.; Kook, D. H.; Park, S. W.; Bek, S. Y.; Lee, E. P.

    2004-10-01

    The advanced spent fuel conditioning process(ACP) proposed to reduce the overall volume of the PWR spent fuel and improve safety and economy of the long-term storage of spent fuel. In the next phase(2004∼2006), the hot test will be carried out for verification of the ACP in a laboratory scale. For the hot test, the hot cell facilities of α- type and auxiliary facilities are required essentially for safe handling of high radioactive materials. As the hot cell facilities for demonstration of the ACP, a existing hot cell of β- type will be refurbished to minimize construction expenditures of hot cell facility. Up to now, the detail design of hot cell facilities and process were completed, and the safety analysis was performed to substantiate secure of conservative safety. The design data were submitted for licensing which was necessary for construction and operation of hot cell facilities. The safety investigation of KINS on hot cell facilities was completed, and the license for construction and operation of hot cell facilities was acquired already from MOST. In this report, the safety analysis report submitted to KINS was summarized. And also, the questionnaires issued from KINS and answers of KAERI in process of safety investigation were described in detail

  8. A State of the Art Report on the Case Study of Hot Cell Decontamination and Refurbishment

    Energy Technology Data Exchange (ETDEWEB)

    Won, H. J.; Jung, C. H.; Moon, J. K.; Park, G. I.; Song, K. C

    2008-08-15

    As the increase of the operation age of the domestic high radiation facilities such as IMEF, PIEF and DFDF, the necessity of decontamination and refurbishment of hot cells in these facilities is also increased. In the near future, the possibilities of refurbishment of hot cells in compliance with the new regulations, the reuse of hot cells for the other purposes and the decommissioning of the facilities also exist. To prepare against the decontamination and refurbishment of hot cells, the reports on the refurbishment, decommissioning and decontamination experiences of hot cells in USA, Japan, France, Belgium and Great Britain were investigated. ANL of USA performed the project on the decontamination of hot cells. The purpose of the project was to practically eliminate the radioactive emissions of Rn-220 to the environment and to restore the hot cells to an empty restricted use condition. The five hot cells were emptied and decontaminated for restricted use. Chemical processing facility in JAEA of Japan was used for the reprocessing study of spent fuels, hot cells in CPF were refurbished from 1995 for the tests of the newly developed reprocessing process. In a first stage, decommissioning and decontamination were fully performed by the remote operation Then, decommissioning and decontamination were performed manually. By the newly developed process, they reported that the radiation exposure of workers were satisfactorily reduced. In the other countries, they also make an effort for the refurbishment and decontamination of hot cells and it is inferred that they accumulate experiences in these fields.

  9. Behavior of radioactive organic iodide in an atmosphere of High Temperature Gas-cooled Reactor

    International Nuclear Information System (INIS)

    Saeki, Masakatsu; Nakashima, Mikio; Sagawa, Chiaki; Masaki, Nobuyuki; Hirabayashi, Takakuni; Aratono, Yasuyuki

    1990-06-01

    Formation and decomposition behavior of radioactive organic iodide have been studied in an atmosphere of High Temperature Gas-cooled Reactor (High Temperature Engineering Test Reactor, HTTR). Na 125 I was chosen for radioactive iodine source instead of CsI diffusing from coated fuel particles. Na 125 I adsorbed on graphite was heated in pure He and He containing O 2 or H 2 O atmosphere. The results obtained are as follows. It was proved that organic iodide was formed with organic radicals released from graphite even in He atmosphere. Thus, the interchange rate of inorganic iodide with organic iodide was remarkably decreased with prolonged preheat-treatment period at 1000degC. Organic iodide formed was easily decomposed by its recirculation into hot reaction tube kept at 900degC. When organic iodide was passed through powdered graphite bed, more than 70% was decomposed at 90degC. Oxygen and water vapour intermixed in He suppressed the interchange rate of inorganic iodide with organic iodide. These results suggest that organic iodide rarely exists in the pressure vessel under normal operating condition of HTTR, and, under hypothetical accident condition of HTTR, organic iodide fraction never exceeds the value used for a safety assessment of light water reactor. (author)

  10. Methods for Characterisation of unknown Suspect Radioactive Samples

    International Nuclear Information System (INIS)

    Sahagia, M.; Grigorescu, E.L.; Luca, A.; Razdolescu, A.C.; Ivan, C.

    2001-01-01

    Full text: The paper presents various identification and measurement methods, used for the expertise of a wide variety of suspect radioactive materials, whose circulation was not legally stated. The main types of examined samples were: radioactive sources, illegally trafficked; suspect radioactive materials or radioactively contaminated devices; uranium tablets; fire detectors containing 241 Am sources; osmium samples containing radioactive 185 Os or enriched 187 Os. The types of analyses and determination methods were as follows: the chemical composition was determined by using identification reagents or by neutron activation analysis; the radionuclide composition was determined by using gamma-ray spectrometry; the activity and particle emission rates were determined by using calibrated radiometric equipment; the absorbed dose rate at the wall of all types of containers and samples was determined by using calibrated dose ratemeters. The radiation exposure risk for population, due to these radioactive materials, was evaluated for every case. (author)

  11. Stress Analysis for Mobile Hot Cell Design

    International Nuclear Information System (INIS)

    Muhammad Hannan Bahrin; Anwar Abdul Rahman; Mohd Arif Hamzah

    2015-01-01

    Prototype and Plant Development Centre (PDC) is developing a Mobile Hot Cell (MHC) to handle and manage Spent High Activity Radioactive Sources (SHARS), such as teletherapy heads and dry irradiators. At present, there are two units of MHC in the world, one in South Africa and the other one in China. Malaysian Mobile MHC is developed by Malaysian Nuclear Agency with the assistance of IAEA expert, based on the design of South Africa and China, but with improved features. Stress analysis has been performed on the design to fulfill the safety requirement in MHC operation. This paper discusses the loading effect analysis from the radiation shielding materials to the MHC wall structure, roof supporting column and window structure. (author)

  12. Radioactive waste management solutions

    International Nuclear Information System (INIS)

    Siemann, Michael

    2015-01-01

    One of the more frequent questions that arise when discussing nuclear energy's potential contribution to mitigating climate change concerns that of how to manage radioactive waste. Radioactive waste is produced through nuclear power generation, but also - although to a significantly lesser extent - in a variety of other sectors including medicine, agriculture, research, industry and education. The amount, type and physical form of radioactive waste varies considerably. Some forms of radioactive waste, for example, need only be stored for a relatively short period while their radioactivity naturally decays to safe levels. Others remain radioactive for hundreds or even hundreds of thousands of years. Public concerns surrounding radioactive waste are largely related to long-lived high-level radioactive waste. Countries around the world with existing nuclear programmes are developing longer-term plans for final disposal of such waste, with an international consensus developing that the geological disposal of high-level waste (HLW) is the most technically feasible and safe solution. This article provides a brief overview of the different forms of radioactive waste, examines storage and disposal solutions, and briefly explores fuel recycling and stakeholder involvement in radioactive waste management decision making

  13. Device for fracturing silicon-carbide coatings on nuclear-fuel particles

    Science.gov (United States)

    Turner, L.J.; Willey, M.G.; Tiegs, S.M.; Van Cleve, J.E. Jr.

    This invention is a device for fracturing particles. It is designed especially for use in hot cells designed for the handling of radioactive materials. In a typical application, the device is used to fracture a hard silicon-carbide coating present on carbon-matrix microspheres containing nuclear-fuel materials, such as uranium or thorium compounds. To promote remote control and facilitate maintenance, the particle breaker is pneumatically operated and contains no moving parts. It includes means for serially entraining the entrained particles on an anvil housed in a leak-tight chamber. The flow rate of the gas is at a value effecting fracture of the particles; preferably, it is at a value fracturing them into product particulates of fluidizable size. The chamber is provided with an outlet passage whose cross-sectional area decreases in the direction away from the chamber. The outlet is connected tangentially to a vertically oriented vortex-flow separator for recovering the product particulates entrained in the gas outflow from the chamber. The invention can be used on a batch or continuous basis to fracture the silicon-carbide coatings on virtually all of the particles fed thereto.

  14. Method for fracturing silicon-carbide coatings on nuclear-fuel particles

    Science.gov (United States)

    Turner, Lloyd J.; Willey, Melvin G.; Tiegs, Sue M.; Van Cleve, Jr., John E.

    1982-01-01

    This invention is a device for fracturing particles. It is designed especially for use in "hot cells" designed for the handling of radioactive materials. In a typical application, the device is used to fracture a hard silicon-carbide coating present on carbon-matrix microspheres containing nuclear-fuel material, such as uranium or thorium compounds. To promote remote control and facilitate maintenance, the particle breaker is pneumatically operated and contains no moving parts. It includes means for serially entraining the entrained particles on an anvil housed in a leak-tight chamber. The flow rate of the gas is at a value effecting fracture of the particles; preferably, it is at a value fracturing them into product particulates of fluidizable size. The chamber is provided with an outlet passage whose cross-sectional area decreases in the direction away from the chamber. The outlet is connected tangentially to a vertically oriented vortex-flow separator for recovering the product particulates entrained in the gas outflow from the chamber. The invention can be used on a batch or continuous basis to fracture the silicon-carbide coatings on virtually all of the particles fed thereto.

  15. Hot Ductility Behavior of an 8 Pct Cr Roller Steel

    Science.gov (United States)

    Wang, Zhenhua; Sun, Shuhua; Shi, Zhongping; Wang, Bo; Fu, Wantang

    2015-04-01

    The hot ductility of an 8 pct Cr roller steel was determined between 1173 K and 1473 K (900 °C and 1200 °C) at strain rates of 0.01 to 10 s-1 through tensile testing. The fracture morphology was observed using scanning electron microscopy, and the microstructure was examined through optical microscopy and transmission electron microscopy. The dependence of the hot ductility behavior on the deformation conditions, grain size, and precipitation was analyzed. The relationship between the reduction in area and the natural logarithm of the Zener-Hollomon parameter (ln Z) was found to be a second-order polynomial. When ln Z was greater than 40 s-1, the hot ductility was poor and fracture was mainly caused by incompatible deformation between the grains. When ln Z was between 32 and 40 s-1, the hot ductility was excellent and the main fracture mechanism was void linking. When ln Z was below 32 s-1, the hot ductility was poor and fracture was mainly caused by grain boundary sliding. A fine grain structure is beneficial for homogenous deformation and dynamic recrystallization, which induces better hot ductility. The effect of M7C3 carbide particles dispersed in the matrix on the hot ductility was small. The grain growth kinetics in the 8 pct Cr steel were obtained between 1373 K and 1473 K (1100 °C and 1200 °C). Finally, optimized preheating and forging procedures for 8 pct Cr steel rollers are provided.

  16. Method of encapsulating waste radioactive material

    International Nuclear Information System (INIS)

    Forrester, J.A.; Rootham, M.W.

    1982-01-01

    When encapsulating radioactive waste including radioactive liquid having a retardant therein which retards the setting of cements by preventing hydration at cement particles in the mix, the liquid is mixed with ordinary Portland cement and subjected, in a high shear mixer, to long term shear far in excess of that needed to form ordinary grout. The controlled utilization of the retardants plus shear produces a thixotropic paste with extreme moldability which will not bleed, and finally sets more rapidly than can be expected with normal cement mixtures forming a very strong product. (author)

  17. Pump station for radioactive waste water

    Science.gov (United States)

    Whitton, John P.; Klos, Dean M.; Carrara, Danny T.; Minno, John J.

    2003-11-18

    A pump station for transferring radioactive particle containing waste water, includes: (a.) an enclosed sump having a vertically elongated right frusto conical wall surface and a bottom surface and (b.) a submersible volute centrifugal pump having a horizontally rotating impeller and a volute exterior surface. The sump interior surface, the bottom surface and the volute exterior surface are made of stainless steel having a 30 Ra or finer surface finish. A 15 Ra finish has been found to be most cost effective. The pump station is used for transferring waste water, without accumulation of radioactive fines.

  18. Particulate hot gas stream cleanup technical issues

    Energy Technology Data Exchange (ETDEWEB)

    Pontius, D.H.; Snyder, T.R.

    1999-09-30

    The analyses of hot gas stream cleanup particulate samples and descriptions of filter performance studied under this contract were designed to address problems with filter operation that have been linked to characteristics of the collected particulate matter. One objective of this work was to generate an interactive, computerized data bank of the key physical and chemical characteristics of ash and char collected from operating advanced particle filters and to relate these characteristics to the operation and performance of these filters. The interactive data bank summarizes analyses of over 160 ash and char samples from fifteen pressurized fluidized-bed combustion and gasification facilities utilizing high-temperature, high pressure barrier filters.

  19. Cycling the hot CNO: a teaching methodology

    Science.gov (United States)

    Frost-Schenk, J. W.; Diget, C. Aa; Bentley, M. A.; Tuff, A.

    2018-03-01

    An interactive activity to teach the hot Carbon, Nitrogen and Oxygen (HCNO) cycle is proposed. Justification for why the HCNO cycle is important is included via an example of x-ray bursts. The activity allows teaching and demonstration of half-life, nuclear isotopes, nuclear reactions, protons and α-particles, and catalytic processes. Whilst the process example is specific to astrophysics it may be used to teach more broadly about catalytic processes. This practical is designed for use with 10-20 participants, with the intention that the exercise will convey nuclear physics principles in a fun and interactive manner.

  20. The dispersion of radioactive aerosols in fires

    International Nuclear Information System (INIS)

    Buijs, K.; Chavane de Dalmassy, B.; Pickering, S.

    1989-01-01

    Experimental results are reported on the resuspension, due to fire, of radioactive nuclear fuel particles from a variety of substrates. Experiments were carried out both on large and small scale. In small-scale fires uranium-plutonium oxide particles were used and in the large-scale fires cerium-europium oxide particles were used. The mechanisms of particle resuspension were investigated in separate series of experiments. It was found that in small-scale fires up to 20% of the particle inventory can be resuspended and in large-scale fires up to 75%. In both cases most of the resuspended material deposits within the fire chamber and a maximum of 2% is carried into the ventilation duct at the outlet of the fire chamber. The predominant resuspension mechanisms are bubble bursting in small-scale fires and turbulence in large-scale fires. (orig.)