共查询到20条相似文献,搜索用时 15 毫秒
1.
N. N. Bazarbaev A. Kh. Inoyatov I. T. Muminov D. Sh. Rashidova A. K. Mukhamedov A. N. Safarov 《Atomic Energy》2012,111(4):295-300
7Be fallout measurements performed around Samarkand in 2002–2009 are presented. The calendar period included in this research
covers the ascending part of the 23rd solar activity cycle; this part of the cycle corresponded to a decrease of the monthly
average value of the Wolf number from 60 to <5. The linear correlation observed between the fallout and amount of wet precipitation
indicates that the latter plays the main role in the removal of 7Be from the troposphere. The average seasonal 7Be fallout is 223 ± 46 Bq/m2 during winter, 324 ± 66 Bq/m2 during spring, 75 ± 29 Bq/m2 during summer, and 189 ± 43 Bq/m2 during fall. These measurements make it possible to evaluate the contribution of precipitation in the form of dust and dew
to the total 7Be fallout during the summer. The correlation between the solar radiation and 7Be fallout is confirmed. 相似文献
2.
A. A. Alekseev A. A. Bergman A. I. Berlev E. A. Koptelov A. S. Egorov B. F. Samylin B. I. Fursov V. S. Shorin 《Atomic Energy》2011,109(6):408-416
The fission cross sections of 246–248Cm nuclei for neutron energies 0.1 eV–20 keV have been measured using an SVZ-100 lead moderation time neutron spectrometer
at the Institute of Nuclear Research of the Russian Academy of Sciences. The fission resonance integrals have been calculated.
The results are compared with the existing data and recommended evaluations. 相似文献
3.
Abdullah Aydin 《Journal of Fusion Energy》2010,29(5):476-480
In this study, the 3He-emission cross sections for 27Al, 54,56Fe, 197Au, 208Pb and 209Bi target nuclei have been calculated at 62 MeV proton energy. In these calculations, the pre-equilibrium effects have been
investigated. The pre-equilibrium calculations involve the geometry dependent hybrid model and hybrid model. A comparison
with theoretical calculations (ALICE/ASH) has been performed and the empirical formulas for the 3He- emission cross sections produced at 62 MeV proton energy have been derived. 相似文献
4.
A. A. Alekseev A. A. Bergman A. I. Berlev E. A. Koptelev A. S. Egorov B. F. Samylin B. I. Fursov V. S. Shorin 《Atomic Energy》2011,110(1):51-59
The fission cross sections of 246Cm, 247Cm, and 248Cm isotopes measured with an SVZ-100 spectrometer, based on neutron moderation in lead, at the Institute of Nuclear Research
of the Russian Academy of Sciences are analyzed. The area of the resolved resonances is calculated, and their neutron and
fission widths are determined. The results are compared with existing data and recommended evaluations. 相似文献
5.
Nickel is an important element in fusion reactor technologies and astrophysical applications. Therefore, the knowledge of astrophysical S-factors and cross-sections on nickel isotopes is needed. In this work, the cross sections of the 62Ni(α,n) and 62Ni(α,γ) reactions have been calculated. The alpha capture cross sections was calculated up to 10 MeV. In these theoretical calculations, the TALYS 1.6 and NON-SMOKER codes were used. Also for the 62Ni(α,n) and 62Ni(α,γ) reactions, we calculated the astrophysical S-factors that determine the probability of reaction in low energies. Results of our calculations were checked to the experimental data obtained from EXFOR database. 相似文献
6.
E. Tel N. N. Aktı Ş. Okuducu A. Aydin M. Şahan F. A. Uğur H. Şahan 《Journal of Fusion Energy》2011,30(1):58-63
Neutronic characterization and development of structural materials, neutron multiplier materials, tritium breeders are primarily
important for fusion and hybrid reactors. In order to improve neutron economy, beryllium, lead, bismuth, zirconium are considered
and used as neutron multiplier materials in fusion and hybrid reactor design. In this study, rms charge radii, neutron radii,
mass radii and neutron skin thickness were calculated for 8–18Be isotopes nuclei. The neutron and proton density are calculated for Be isotopes. The results obtained were compared with
the experimental and theoretical results of other researchers by using Hartree–Fock method with an effective interaction with
Skyrme forces. 相似文献
7.
The knowledge of the cross-section is important especially for the fusion and fission reactor technology. In the absence of experimental data or in the difficulty of measuring data, theoretical predictions of nuclear cross-section data are needed to be improved using model calculations or semi-empirical formulas and to be compared with model and formulas to obtain sensitive approaches. In this work, for 7Li and 9Be target nuclei used as blanket materials in fusion reactors, (n,p), (n,α), (n,2n) and (α,n) reaction cross-section data have been evaluated by using some available empirical and semi-empirical cross-section formulas. The (n,p), (n,α), (n,2n) and (α,n) reaction cross-section formulas developed for medium and heavy mass nuclei by some scientist in literature are applied to 7Li and 9Be light nuclei and then results obtained from any systematics are compared with each other and the existing experimental data. 相似文献
8.
Palladium, which is a rare and lustrous silvery-white color from precious metals, plays important role in fusion–fission reactions
and different fields of nuclear technology. In addition, it is used for not only cold fusion experiments but also separation
of hydrogen isotopes researches for fusion reactors. In this study, neutron-emission spectra produced by (p,xn) reactions
for structural fusion material 104,105,106,108,110Pd isotopes have been investigated by a proton beam at 21.6 MeV. Moreover, multiple pre-equilibrium mean free paths constant
from internal transition, and the pre-equilibrium and equilibrium level density parameters have been analyzed for some (p,xn)
neutron-emission spectra calculated. New evaluated hybrid model and geometry dependent hybrid model, full exciton model and
cascade exciton model were used to calculate the pre-equilibrium neutron-emission spectra. For the reaction equilibrium component,
Weisskopf–Ewing model calculations were preferred. The obtained results have been discussed and compared with the available
experimental data and found agreement with each other. 相似文献
9.
Silver plated shields are used in components and structures of fusion reactors that may be effected due to the huge radiation. For this reason, we focused on excitation functions of 107,109Ag on alpha induced reactions. For simplicity to examining the events of nuclear physics, nuclear reaction codes such as ALICE/ASH, TALYS, CEM, EMPIRE, PCROSS, GEANT4 and FLUKA that includes different models have been used for many years. In this study, the cross-sections of (α,xn) reactions, where x = 1–5, for 107,109Ag by using nuclear reaction codes ALICE/ASH and TALYS 1.6 were computed. Hybrid and Geometry Dependent Hybrid Models were used in ALICE/ASH whereas Two-Component Exciton Model was used in TALYS 1.6 reaction codes. Energy ranges of alpha particles for 107Ag and 109Ag were taken into computations as 9.2–96.8 and 10.2–71.2 MeV, respectively. Computed results are also compared each other and with experimental data existing in the literature for each reaction. 相似文献
10.
The knowledge of level density for reaction cross-section calculations are needed for various applications such as fission and fusion reactor design, accelerator driven sub-critical systems, nuclear medicine, neutron capture and astrophysics. In this study, the excitation functions for (p, n) reactions from reaction threshold to 30 MeV proton incident energy on 60Ni, 61Ni, 62Ni and 64Ni isotopes were calculated using TALYS 1.6 nuclear code involving the level density models. This is of importance to the validation of nuclear model approaches with increased predictive power. There are several models of level density that can be used to predict cross-section. In this work, the (p, n) cross-sections would be calculated using three different model of level density, such as constant temperature model, back-shifted fermi gas model and generalized superfluid model on 60,61,62,64Ni reactions. The (p, n) reaction cross-section calculations for 60,61,62,64Ni target nuclei were compared with each other and the experimental nuclear reaction data obtained from EXFOR database. 相似文献
11.
This paper describes equilibrium orbit and stability of negative hydrogen ions (H−) on a four sector of tight design giving 30 MeV protons. We simulated radial and vertical changes of main magnetic field
of Cyclone-30 by multi degree and Fourier functions. Based on measured main magnetic field by IBA (Ion Beam Application),
we calculated coefficients of these functions and investigate equilibrium orbit and stability includes Betetatron frequency,
radial and vertical motion and etc. Advanced graphical tools of MATLAB give good visualization features to created models.
The simulation results are in good agreement with experimental data. 相似文献
12.
A remote-controlled spectrometric collimated detector has been developed for remote radiation examination of reactor rooms.
The apparatus consists of a collimated γ-ray detector, a color video camera and a controller, all secured on a rotating apparatus and rods. An on-board computer,
a SKS-08 Kolibri spectrum analyzer, a power supply for the apparatus, and a controller for rotating apparatus are arranged
in the controller. Three interchangeable sensors for changing the sensitivity of the apparatus – two CsI(Tl) scintillators
– 20 and 5 cm3 photodiodes of the scintillator and a 60 mm3 CdZnTe semiconductor sensor. The collimated detector is for remote measurement of the radiation of high-level radwastes extracted
from the storage pool in the reactor room. At the stage of preparation for and planning of the work, it can be used to determine
the main sources of contamination and evaluate the dose distribution fields. 相似文献
13.
14.
E. Tel M. Şahan A. Aydın M. Bölükdemir H. Şahan F. A. Uğur 《Journal of Fusion Energy》2011,30(1):26-33
In fusion reactor structures, a serious damage mechanism has been gas production in the metallic resulting from diverse nuclear
reactions, mainly through (n, α) and (n, p) reactions above a certain threshold energy. The neutron incident energy around 14–15 MeV is enough to excite the nucleus
for the reactions such as (n, p), (n, d), (n, 2n), (n, t), and (n, α). Design of the fusion reactor, about the 14–15 MeV neutron incident energy reaction cross sections is of great importance
for various target nuclei. In this study, the experimental data have been taken only at 14–15 MeV energy regions from EXFOR
database. The (n, α) reactions for some structural fusion materials such as 27Al, 51V, 52Cr, 55Mn, 56Fe and 58Ni have calculated by using evaluated empirical formulas developed by Tel et al. at 14–15 MeV and calculated with the pre-equilibrium
models up to 20 MeV. The calculated results are discussed and compared with the experimental data taken from EXFOR database. 相似文献
15.
The knowledge of (n, 2n) cross section is very important and necessary in the reactor technology since a significant portion of the fission neutron
spectrum lies above the threshold of (n, 2n) reaction for the most of the reactor materials. The (n, 2n) cross section is neutron multiplier reaction in fusion reactor design. Therefore, (n, 2n) reactions of the selected blanket materials can play a key role for multiplying neutrons in reactor environment. In this
study, for some structural fusion materials (n, 2n) reactions such as 27Al(n, 2n)26Al,
51V(n, 2n)50V,
52Cr(n, 2n)51Cr,
55Mn(n, 2n)54Mn,
56Fe(n, 2n)55Fe and 58Ni (n, 2n)57Ni have been carried out up to 40 MeV incident neutron energy. In these calculations, the pre-equilibrium and equilibrium
effects have been investigated. Also in the present work, the (n, 2n) reaction cross-sections have calculated by using evaluated empirical formulas developed by Tel et al. at 14–15 MeV energy.
The calculated results are discussed and compared with the experimental data taken from EXFOR database. 相似文献
16.
Fusion serves an inexhaustible energy for humankind. Although there have been significant research and development studies
on the inertial and magnetic fusion reactor technology, there is still a long way to go to penetrate commercial fusion reactors
to the energy market. Tritium self-sufficiency must be maintained for a commercial power plant. For self-sustaining (D-T)
fusion driver tritium breeding ratio should be greater than 1.05. So, the working out the systematics of (n, t) reaction cross sections is of great importance for the definition of the excitation function character for the given reaction
taking place on various nuclei at different energies. In this study, (n, t) reactions for some structural fusion materials such as 27Al, 51V, 52Cr, 55Mn, and 56Fe have been investigated. The new calculations on the excitation functions of 27Al(n, t)25Mg, 51V(n, t)49Ti, 52Cr(n, t)50V, 55Mn(n, t)53Cr and 56Fe(n, t)54Mn reactions have been carried out up to 50 MeV incident neutron energy. In these calculations, the pre-equilibrium and equilibrium
effects have been investigated. The pre-equilibrium calculations involve the new evaluated the geometry dependent hybrid model,
hybrid model and the cascade exciton model. Equilibrium effects are calculated according to the Weisskopf–Ewing model. Also
in the present work, we have calculated (n, t) reaction cross-sections by using new evaluated semi-empirical formulas developed by Tel et al. at 14–15 MeV energy. The
calculated results are discussed and compared with the experimental data taken from the literature. 相似文献
17.
E. Tel C. Durgu A. Aydın M. H. Bölükdemir A. Kaplan Ş. Okuducu 《Journal of Fusion Energy》2009,28(4):377-384
In the next century the world will face the need for new energy sources. Nuclear fusion can be one of the most attractive
sources of energy from the viewpoint of safety and minimal environmental impact. Fusion will not produce CO2 or SO2 and thus will not contribute to global warming or acid rain. Achieving acceptable performance for a fusion power system in
the areas of economics, safety and environmental acceptability, is critically dependent on performance of the blanket and
diverter systems which are the primary heat recovery, plasma purification, and tritium breeding systems. Tritium self-sufficiency
must be maintained for a commercial power plant. The hybrid reactor is a combination of the fusion and fission processes.
For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. So working out the systematics
of (n, t) reaction cross-sections are of great importance for the definition of the excitation function character for the given reaction
taking place on various nuclei at energies up to 20 MeV. In this study, we have calculated non-elastic cross-sections by using
optical model for (n, t) reactions at 14–15 MeV energy. We have investigated the excitation function character and reaction Q-values depending on the asymmetry term effect for the (n, t) reaction cross-sections. We have obtained new coefficients for the (n, t) reaction cross-sections. We have suggested semi-empirical formulas including optical model nonelastic effects by fitting
two parameters for the (n, t) reaction cross-sections at 14–15 MeV. We have discussed the odd–even effect and the pairing effect considering binding energy
systematic of the nuclear shell model for the new experimental data and new cross-sections formulas (n, t) reactions developed by Tel et al. We have determined a different parameter groups by the classification of nuclei into even–even,
even–odd and odd–even for (n, t) reactions cross-sections. The obtained cross-section formulas with new coefficients have been discussed and compared with
the available experimental data. 相似文献
18.
E. Tel A. Kaplan A. Aydın S. Özkorucuklu H. Büyükuslu G. Yıldırım 《Journal of Fusion Energy》2010,29(4):312-316
Although there have been significant research and development studies on the inertial and magnetic fusion reactor technology,
there is still a long way to go to penetrate commercial fusion reactors to the energy market. Tritium self-sufficiency must
be maintained for a commercial power plant. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater
than 1.05. So, working out the systematics of (n,t) reaction cross sections and triton emission differential data are important for the given reaction taking place on various
nuclei at different energies. In this study, (n,xt) reactions for some target nuclei as 16O, 27Al, 59Co and 209Bi have been investigated up to 45 MeV incident neutron energy. In the calculations of the triton emission spectra, the pre-equilibrium
and equilibrium effects have been used. The calculated results have been compared with the experimental data taken from the
literature. 相似文献
19.
M. A. Mussaeva E. M. Ibragimova N. M. Mukhamedshina M. I. Muminov S. A. Baitelesov A. A. Dosimbaev 《Atomic Energy》2008,105(3):208-213
The neutron fluxes and the intensity of γ radiation are measured in 26 channels of a VVR-SM reactor and its thermal column. The fast neutron fluxes in the channels
are determined using Ni, Fe, Co, Au, and Mn element monitors with different threshold energies, together with a theoretical
calculation using the MCNP-4C program. The energy distribution of the neutron flux inside the fuel assembly is obtained for
selected channels around the core. The flux of neutrons with energies >1 MeV is in the range (0.5–43)·1012 cm−2sec−1, depending on the location of the channel. A linear correlation is discovered between the induced optical absorption at the
215 nm line (E′ center) of SiO2–BaO glass and the fast neutron flux in the channels. The γ-ray intensity in the thermal channel is estimated for the reactor during operation (∼38.4 Gy/sec) and 24 hours after it is
shut down (∼24.7 Gy/sec) using the E′ centers induced in pure quartz glasses. The observed difference in the efficiency with
which oxygen defects are formed during dry and wet irradiation of glass owing to the radiolysis of water must be taken into
account when developing radiation technology and during the burial of radioactive waste.
Translated from Atomnaya énergiya, Vol. 105, No. 3, pp. 160–164, September, 2008. 相似文献