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Tytuł:
Safety issues as a start point for further investigations of fusion hybrids
Autorzy:
Wójcik, G.
Taczanowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/146801.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
fusion hybrid
radiation damages
safety
transmutation
Opis:
Nuclear power plants supply nearly one sixth of the world electric energy production. Though nuclear power is a very efficient source of energy, it produces dangerous radioactive waste composed of nuclides characterized, among others, by a long decay time and containing also significant quantities of fissible and even fissile materials. Therefore, spent nuclear fuel must be carefully stored for at least hundreds of years, all this time needing permanent supervision. Simultaneously this cumbersome waste contains also important amounts of energy that should not be simply buried forever. Thus, in spite of the fact that ultimate disposal of spent nuclear fuel in adequate geological formations is recognized as safe for the energy hungry world that tries at the same time to avoid CO2 emissions, this is a hardly acceptable solution. Fortunately, there is an effective approach, namely – spent fuel recycling, particularly with the help of nuclear fusion. Simultaneously, one has to admit that this concept has not attained yet technological maturity, thus lengthy and costly investigations still are necessary before nuclear fusion achieves development level adequate to industrial application. Since every nuclear device must be generally safe, therefore this article raises a safety issue of fusion-fission hybrid design. In order to ensure the required reliability of evaluations the development of heterogeneous model of the device was assumed as the starting point for further respective research. The performed calculations have indicated that maintenance of subcriticality even in the case of system collapse is achievable.
Źródło:
Nukleonika; 2012, 57, 4; 447-450
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A statistical model analysis of yields and fluctuations in 200 GeV Au-Au collisions
Autorzy:
Torrieri, G.
Jeon, S.
Rafelski, J.
Powiązania:
https://bibliotekanauki.pl/articles/148435.pdf
Data publikacji:
2006
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
fluctuations
freeze-out is small
heavy-ion collisions
statistical models
Opis:
We show that the simultaneous measurement of yields and fluctuations is capable of falsifying and constraining the statistical hadronization model. We show how such a measurement can test for chemical non-equilibrium, and distinguish between a high temperature chemically equilibrated freeze-out from a supercooled freeze-out with an oversaturated phase space. We perform a fit, and show that both yields and fluctuations measured at RHIC 200 GeV can be accounted for within the second scenario, with both the light and strange quark phase space saturated significantly above detailed balance. We point to the simultaneous fit of the K/đ fluctuation and the K*/K ratio as evidence that the effect of hadronic re-interactions after freeze-out is small.
Źródło:
Nukleonika; 2006, 51,suppl.3; 99-103
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positron-annihilation and photoluminescence studies of nanostructured ZrO2
Autorzy:
Fidelus, J. D.
Karbowski, A.
Mariazzi, S.
Brusa, R. S.
Karwasz, G.
Powiązania:
https://bibliotekanauki.pl/articles/146313.pdf
Data publikacji:
2010
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
positron annihilation
zirconia nanopowders
photoluminescence
Opis:
In the present work, photoluminescence and Doppler broadening depth-resolved positron annihilation spectroscopy was performed on pure zirconia nanopowders. Zirconia nanopowders were grown by a hydrothermal microwave-driven process followed by annealing in oxygen atmosphere. Photoluminescence under 274 nm wavelength excitation from a 150 W high-pressure Xe exhibits similar spectra, in the region from 320 to 820 nm, although its intensity depends on the annealing. Positron annihilation Doppler-broadening spectra show low values of the normalized S-parameter, varying little with the depth, from 0.495 on the surface to 0.47-0.49 in bulk. Both high the annealing temperature and oxygen concentrations, lead to low bulk S-values. The ortho-positronium (o-Ps) fraction is about 10-11% for all samples on the surface, whereas it is reduced to 7-8% in the bulk for samples annealed at 700°C and 5-6% for samples annealed at 800°C. Both photoluminescence (PL) and positron studies show the presence of defects in all samples. The o-Ps signal suggests a high porosity of samples, particularly at a depth down to 10 nm.
Źródło:
Nukleonika; 2010, 55, 1; 85-89
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of some physicochemical and rheological properties of irradiated honey
Autorzy:
Bera, A
Almeida-Muradian, L. G.
Sabato, S. F.
Powiązania:
https://bibliotekanauki.pl/articles/147025.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
gamma radiation
honey
rheology
physicochemical properties
Opis:
Honey is a sweet substance produced by bees, well appreciated in many places and its consumption has been increased either as raw material or as a food ingredient. Its use as food by the consumer, or even for exportation, implies safety inherent in its quality and processing control. Gamma radiation can be applied in food or ingredients for many objectives like pathogens microorganisms’ reduction, disinfestations, and sterilization. The aim of this work was to verify some physicochemical modifications, as well as rheological evaluation of honey submitted to irradiation at 10 kGy. The physicochemical parameters analyzed were: moisture, HMF, free acidity, pH, sugars and ash. The rheological behavior was measured at different temperatures. The results indicated that few changes occurred; the rheological behavior was not impaired and did not present any significant physicochemical alteration.
Źródło:
Nukleonika; 2008, 53, suppl. 2; 85-87
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Decomposition of toluene in air mixtures under electron beam irradiation
Autorzy:
Sun, Y.
Chmielewski, A. G.
Bułka, S.
Zimek, Z.
Powiązania:
https://bibliotekanauki.pl/articles/148028.pdf
Data publikacji:
2009
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
toluene
4-chlorotoluene
decomposition
electron beam
Opis:
The model gases of toluene-air mixtures were prepared by blowing technical air into liquid toluene and then irradiated with an ILU-6 accelerator located at the Institute of Nuclear Chemistry and Technology (INCT), Poland. It was found that the decomposition efficiency of toluene increases with absorbed dose and decreases with initial concentration of toluene. At 14.5 kGy dose, the decomposition efficiencies of toluene were 50, 37 and 34.5% for the initial concentrations of toluene 32.0, 63.4 and 78.0 ppm, respectively. At 58.0 kGy dose, the decomposition efficiencies of toluene were 93.8 and 78.1%, the initial concentrations of toluene being 32.0 and 63.4 ppm, respectively. Benzaldehyde was identified as one of the by-products of toluene decomposition in an air mixture. The decomposition efficiency and by-product formation under EB irradiation were compared between toluene and 4-chlorotoluene.
Źródło:
Nukleonika; 2009, 54, 2; 65-70
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation of decomposition of dichloroethylenes (trans-DCE, cis-DCE, 1,1-DCE)/air under electron beam irradiation
Autorzy:
Sun, Y.
Chmielewski, G.
Bułka, S.
Zimek, Z.
Nichipor, H.
Powiązania:
https://bibliotekanauki.pl/articles/146568.pdf
Data publikacji:
2007
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
trans-dichloroethylene
cis-dichloroethylene
1,1-dichloroethylene
electron beam
decomposition
mechanism
Opis:
On the basis of the experimental results, computer simulations of decomposition of dichloroethylenes for three isomers (trans-DCE, cis-DCE, 1,1-DCE) in air under electron beam were carried out. Computer code “Kinetic” and “Gear” method were used. Calculation results well agree with the experimental results. Decomposition efficiency of DCE is mainly determined by Cl- dissociated secondary electron attachment, followed by Cl radical addition reaction with DCE.
Źródło:
Nukleonika; 2007, 52, 2; 59-67
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Uranium and neodymium partitioning in alkali chloride melts using low-melting gallium-based alloys
Autorzy:
Melchakov, S. Y.
Maltsev, D. S.
Volkovich, V. A.
Yamshchikov, L. F.
Lisienko, D. G.
Osipenko, A. G.
Rusakov, M. A.
Powiązania:
https://bibliotekanauki.pl/articles/146407.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
neodymium
uranium
gallium
separation factor
reductive extraction
pyrochemical reprocessing
Opis:
Partitioning of uranium and neodymium was studied in a ‘molten chloride salt – liquid Ga-X (X = In or Sn) alloy’ system. Chloride melts were based on the low-melting ternary LiCl-KCl-CsCl eutectic. Nd/U separation factors were calculated from the thermodynamic data as well as determined experimentally. Separation of uranium and neodymium was studied using reductive extraction with neodymium acting as a reducing agent. Efficient partitioning of lanthanides (Nd) and actinides (U), simulating fission products and fissile materials in irradiated nuclear fuels, was achieved in a single stage process. The experimentally observed Nd/U separation factor valued up to 106, depending on the conditions.
Źródło:
Nukleonika; 2015, 60, No. 4, part 2; 915-920
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recent development in ECR sources
Autorzy:
Bieth, C.
Kantas, S.
Sortais, P.
Kanjilal, D.
Rodrigues, G.
Powiązania:
https://bibliotekanauki.pl/articles/148676.pdf
Data publikacji:
2003
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
ion source
ECR source
superconducting coils
high temperature superconducting wires
high charge state ion source
ion implantation
Opis:
Recent developments and improvements on the ECR ion source family at PANTECHNIK S.A. are presented. A lot of work has been done in the Ion Implantation Technology with the MICROGAN IndustryŽ source: more than 3 mA have been produced on B1+, P1+ and few hundred žAe on charge state 3+, 4+. Three other developments are described in this paper: a) the construction of the first source using high temperature superconducting coils (30 K) PKSUSŽ - Space Cryomagnetics (UK), in collaboration with NSC (New Delhi); b) the construction of the PHOENIX ECR source (used in the “1+/n+” process for radioactive beam) for different laboratories; c) and the first results on PK 2.45 (a cheap source working at 2.45 GHz) able to produce high current of monocharged beam. We will also present some special products for beam acceleration and diagnosis.
Źródło:
Nukleonika; 2003, 48,suppl.2; 93-98
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Toward a European Network of Positron Laboratories
Autorzy:
Karwasz, G. P.
Brusa, R. S.
Egger, W.
Ogorodnikova, O. V.
Powiązania:
https://bibliotekanauki.pl/articles/146548.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
positron beams
material science
thermonuclear reaction
Opis:
Some applications of controlled-energy positron beams in material studies are discussed. In porous organic polysilicates, measurements of 3γ annihilation by Doppler broadening (DB) method at the Trento University allowed to trace pore closing and filling by water vapor. In silicon coimplanted by He+ and H+, DB data combined with positron lifetime measurements at the München pulsed positron beam allowed to explain Si blistering. Presently measured samples of W for applications in thermonuclear reactors, irradiated by W+ and electrons, show vast changes of positron lifetimes, indicating complex dynamics of defects.
Źródło:
Nukleonika; 2015, 60, No. 4, part 1; 733-739
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stable isotope deuterium as a natural tracer of mixing processes in rivers
Autorzy:
Palige, J.
Ptaszek, S.
Zimnicki, R.
Chmielewski, A. G.
Wierzchnicki, R.
Powiązania:
https://bibliotekanauki.pl/articles/146756.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
stable isotopes
tracer
deuterium
oxygen-18
river
water flow
Opis:
The possibility of application of naturally existing differences in isotope contents 18O/16O, 2H/1H in waters for investigation of transport and mixing of various waters in the tributary-river system is presented. Experiments carried out on the Bug-Narew rivers-Zegrze Lake and the BugoNarew-Vistula rivers systems have indicated that the hydrogen isotope ratio 2H/1H can be used as an intrinsic tracer of natural mixing processes occurring in rivers. The IRMS methodology was used for isotope ratio measurement of water samples. The degrees of water mixing as a function of distance from the confluence point of rivers were determined. The obtained results indicate that in water systems where the natural differences in ?2H are higher than 5‰ this technique can replace the time-consuming and expensive dye (or radiotracer) dispersion tests for evaluation of pollutant transport in rivers.
Źródło:
Nukleonika; 2008, 53, 2; 63-67
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical study of dose and dose rate effect on trichloroethylene (HClC=CCl2) decomposition in dry and humid air under electron beam irradiation
Autorzy:
Nichipor, H.
Yacko, S.
Sun, Y.
Chmielewski, A. G.
Zimek, Z.
Powiązania:
https://bibliotekanauki.pl/articles/146819.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
trichloroethylene
electron beam decomposition
computer simulation
Opis:
Experimental data related to C2HCl3 (TCE) removal in dry and humid (200-1000 ppm of H2O) air, respectively, in ambient conditions under electron beam irradiation in the dose range of 1-40 kGy has been published in the literature. Based on the experimental results a theoretical model of C2HCl3 decomposition was proposed for the kinetic mechanism of such process. The active radicals of Cl, O and OH play an important role in the decomposition of TCE. According to the calculations performed, the Cl- dissociative electron attachment predominates in the initial stage of C2HCl3 decomposition. Cl radical accelerates this degradation by chain process in both humid and dry air, respectively. The OH radical produced in humid air also enhances the decomposition process of TCE.
Źródło:
Nukleonika; 2008, 53, 1; 11-16
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of thermal neutron detection capability of a CdZnTe detector in a mixed gamma-neutron radiation field
Autorzy:
Yücel, H.
Narttürk, R. B.
Zümrüt, S.
Gedik, G.
Karadag, M.
Powiązania:
https://bibliotekanauki.pl/articles/146914.pdf
Data publikacji:
2018
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
neutron detection
CdZnTe
prompt gamma ray
thermal neutron
cadmium
neutron sensitivity
241Am-Be source
Opis:
The aim of this study was to investigate the thermal neutron measurement capability of a CdZnTe detector irradiated in a mixed gamma-neutron radiation fi eld. A CdZnTe detector was irradiated in one of the irradiation tubes of a 241Am-Be source unit to determine the sensitivity factors of the detector in terms of peak count rate (counts per second [cps]) per neutron flux (in square centimeters per second) [cps/neutron•cm–2•s–1]. The CdZnTe detector was covered in a 1-mm-thick cadmium (Cd) cylindrical box to completely absorb incoming thermal neutrons via 113Cd(n,γ) capture reactions. To achieve, this Cd-covered CdZnTe detector was placed in a well-thermalized neutron fi eld (f-ratio = 50.9 ± 1.3) in the irradiation tube of the 241Am-Be neutron source. The gamma-ray spectra were acquired, and the most intense gamma-ray peak at 558 keV (0.74 γ/n) was evaluated to estimate the thermal neutron fl ux. The epithermal component was also estimated from the bare CdZnTe detector irradiation because the epithermal neutron cutoff energy is about 0.55 eV at the 1-mm-thick Cd filter. A high-density polyethylene moderating cylinder box can also be fi tted into the Cd fi lter box to enhance thermal sensitivity because of moderation of the epithermal neutron component. Neutron detection sensitivity was determined from the measured count rates from the 558 keV photopeak, using the measured neutron fluxes at different irradiation positions. The results indicate that the CdZnTe detector can serve as a neutron detector in mixed gamma-neutron radiation fields, such as reactors, neutron generators, linear accelerators, and isotopic neutron sources. New thermal neutron filters, such as Gd and Tb foils, can be tested instead of the Cd filter due to its serious gamma-shielding effect.
Źródło:
Nukleonika; 2018, 63, 3; 59-64
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of external wedge on the photoneutron dose equivalent at a high energy medical linac
Autorzy:
Hashemi, , S. M.
Raisali, G.
Taheri, M.
Majdabadi, A.
Ghafoori, M.
Powiązania:
https://bibliotekanauki.pl/articles/147071.pdf
Data publikacji:
2011
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
photoneutron
linac
polycarbonate (PC)
external wedge
radiotherapy
Opis:
Medical linacs used in radiotherapy produce bremsstrahlung spectra. In the energy range from 8 to 25 MV medical linacs produce, besides the clinically useful electron and photon beams, secondary neutrons. The aim of this study was to investigate the effect of an external wedge filter on the photoneutron dose equivalent produced by a medical linac at patient plane. Polycarbonate (PC) films were used for the determination of photoneutron dose equivalent produced by a Varian 2100 C/D linac working at 18 MV photon mode. Neutron dose equivalent was measured at distances 0, 10, 20 and 50 cm from the center of the X-ray beam for open field and after inserting a wedge filter. It was noted that by inserting the external wedge in the path of the X-ray beam, the photoneutron dose equivalent was increased compared to open field. It can be concluded that an external wedge, made from heavy materials may act like the other components of linac head, producing undesired photoneutrons and thus increasing patient dose.
Źródło:
Nukleonika; 2011, 56, 1; 49-51
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dense plasma source development and jet injection in Globus-M*
Autorzy:
Voronin, , V. A.
Gusev, V. K.
Petrov, Y. V.
Mukhin, E. E.
Tolstyakov, S. Y.
Kurskiev, G. S.
Kochergin, M. M.
Hellblom, K. G.
Powiązania:
https://bibliotekanauki.pl/articles/147768.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
plasma gun
spherical tokamak
fuelling system
Opis:
Progress in the development of a plasma jet source and its utilization for injection of hydrogen plasma and neutral gas jets into the Globus-M spherical tokamak are presented. The latest version of the high kinetic energy gas and plasma jet source with titanium hydride grains is described. Reproducibility of the gas jet generation was increased due to automatic loading of fresh grains into the source before every shot. It allows producing stable gas release for many discharges. Impurity radiation intensity from the plasma jet was decreased by more than 100 times by preliminary processing titanium hydrate grains and developing a new filter. The result of special experiments on two colliding jets is discussed. It was confirmed that the plasma jet recombines into a gas jet after it escapes the source edge and has a kinetic energy higher than the hydrogen ionization potential. Hydrogen plasma jet with low impurity content has a density up to 2 × 1022 m-3, a total number of accelerated particles (1-5) × 1019 and a flow velocity of ~ 200 km/s. It was used as an instrument for density control in Globus-M. Jet injection into deuterium plasma core during current plateau phase led to fast density increase in all spatial points of the plasma column including the plasma central region. Such injection allowed density doubling in the tokamak plasma. The model predictions are consistent with the experimental observations of the density raise recorded by the interferometer and Thomson scattering.
Źródło:
Nukleonika; 2008, 53, 3; 103-109
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on biological activity of chitosan after radiation processing
Autorzy:
Gryczka, U.
Gawrońska, A.
Migdał, W
Gawroński, S. W.
Chmielewski, A. G.
Powiązania:
https://bibliotekanauki.pl/articles/148626.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
chitosan
biostimulators
ionizing radiation
willow
biomass
Opis:
In recent years there is a trend in industry to limit the usage of chemical compounds. Natural polymers are new promising materials that possess important properties like biodegrability or lack of toxicity. Radiation processing of natural occurring polymers is an area of current research for development of new applications. The aim of this study was to determine the impact of ionizing radiation modification on bioactivity of a natural polysaccharide. Chitosan with different molecular weights was investigated as a biostimulator – a biologically active substance that stimulates some growth processes in plants. Chitosan in solid state was irradiated with electron beam from an electron beam accelerator Elektronika 10-10 with a dose range from 50 to 300 kGy. The effects of irradiation on the molecular weight of chitosan were investigated by viscosity and GPC measurements. Non-irradiated and irradiated chitosan at concentrations 0.001, 0.01, 0.1 and 1 g/dm3 were used for greenhouse tests of its activity for growth promotion of Salix viminalis L. var. gigantea plant. Uniform rooted cuttings (20 per combination) were selected for the test and cultivated in aerated hydroponics culture containing Hoagland’s nutrient solutions plus respective amounts of chitosan. After six weeks of plant exposure to chitosan, data of selected parameters of plant growth were collected. In most cases, except the highest concentration, both forms of chitosan had stimulatory effect on leaf area, length of roots and of newly developed shoots. Also fresh and dry weights of these organs were greater in chitosan treated plants. The highest concentration of chitosan was stimulatory only for a number of roots and newly developed shoots while for other parameters was inhibitory. In comparable concentrations the stimulatory effect was greater for chitosan irradiated in comparison with the non-irradiated one.
Źródło:
Nukleonika; 2008, 53, suppl. 2; 73-76
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł

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