Refine Search

New Search

Results in Journal World Journal of Nuclear Science and Technology: 246

(searched for: journal_id:(1139065))
Page of 5
Articles per Page
by
Show export options
  Select all
Hugo A. Borbón-Nuñez, Claudio Furetta
World Journal of Nuclear Science and Technology, Volume 07, pp 274-283; https://doi.org/10.4236/wjnst.2017.74021

Abstract:
The aim of this paper is to give some simplified expressions related to the peak shape method. The modified equations have been used to calculate the activation energy (E) of commercial thermoluminescent dosimeters (TLD), as well as of ZnO thermoluminescent material produced in laboratory; the values so determined have been compared to the values obtained using the classical expressions of the peak shape method. The modified equations proposed are as a function of peak shape parameters or the peak temperature at the maximum. This expression could be useful to obtain approximated E values in the case of complex glow curves as well, when the peaks are not well resolved but the peak temperature at the maximum may be easily determined.
M. P. Silverman
World Journal of Nuclear Science and Technology, Volume 07, pp 252-273; https://doi.org/10.4236/wjnst.2017.74020

Abstract:
Residence time in a flow measurement of radioactivity is the time spent by a pre-determined quantity of radioactive sample in the flow cell. In a recent report of the measurement of indoor radon by passive diffusion in an open volume (i.e. no flow cell or control volume), the concept of residence time was generalized to apply to measurement conditions with random, rather than directed, flow. The generalization, leading to a quantity Δtr, involved use of a) a phenomenological alpha-particle range function to calculate the effective detection volume, and b) a phenomenological description of diffusion by Fick’s law to determine the effective flow velocity. This paper examines the residence time in passive diffusion from the micro-statistical perspective of single-particle continuous Brownian motion. The statistical quantity “mean residence time” Tr is derived from the Green’s function for unbiased single-particle diffusion and is shown to be consistent with Δtr. The finite statistical lifetime of the randomly moving radioactive atom plays an essential part. For stable particles, Tr is of infinite duration, whereas for an unstable particle (such as 222Rn), with diffusivity D and decay rate λ, Tr is approximately the effective size of the detection region divided by the characteristic diffusion velocity . Comparison of the mean residence time with the time of first passage (or exit time) in the theory of stochastic processes shows the conditions under which the two measures of time are equivalent and helps elucidate the connection between the phenomenological and statistical descriptions of radon diffusion.
Alexander Ivanchin
World Journal of Nuclear Science and Technology, Volume 07, pp 232-251; https://doi.org/10.4236/wjnst.2017.74019

Abstract:
Theoretical physics makes a wide use of differential equations for which only a potential solution is applied. The possibility that these equations may have a non-potential solution is ruled out and not considered. In this paper an exact non-potential solution of the continuity equation is described. The electric field of an elementary charged particle consists of two components: the known Potential Component (PC) produced by the charge and the earlier unknown Non-potential Component (NC) with a zero charge. Charged particles have both components, while a neutron has only the NC. The proton and neutron NC ensures similarity of their properties. The PC is spherically symmetric and NC is axisymmetric. Therefore, to describe an elementary particle, one should take into account both its spatial coordinates and the NC orientation. The particle interaction is determined by their NC mutual orientation. Neglecting the latter leads to indefiniteness of the interaction result. In a homogeneous electric field, the force acting on the NC is zero. Therefore, a charged particle possessing the NC will behave like a potential one. In an inhomogeneous field, the situation is principally different. Due to the NC there occurs an interaction between a neutron and a proton. The non-potential field results in the existence of two types of neutrons: a neutron and an antineutron. A neutron repels from a proton ensuring scattering of neutrons on protons. An antineutron is attracted to a proton leading to its annihilation. The NC produces the magnetic dipole moment of an elementary particle.
Bright Madinka Mweetwa, Emmanuel Ampomah-Amoako, Edward Horga Korbla Akaho
World Journal of Nuclear Science and Technology, Volume 07, pp 223-231; https://doi.org/10.4236/wjnst.2017.74018

Abstract:
The Program for the Analysis of Reactor Transients/Argonne National Laboratory (PARET/ANL) code was used to predict the thermal hydraulic behaviour of the Ghana Research Reactor-1 after adding 9.0 mm of beryllium to the top shim tray of the core. The core was analysed for reactivity insertions 2.1 mk, 3.0 mk, 4.0 mk, 5.0 mk and 6.7 mk, respectively. The reactor is still safe to operate in the range 2.1 mk to 4.0 mk. However, 2.1 mk would be ideal since the reactor automatic shutdown (SCRAM) is set not to exceed 120% of reactor nominal power.
Gábor Bihari
World Journal of Nuclear Science and Technology, Volume 07, pp 206-222; https://doi.org/10.4236/wjnst.2017.73017

Abstract:
While experimenting with the more and more popular neodymium magnetic ball sets, the author developed a method, by which models of atomic nuclei can be created. These macroscopic models visually represent several features of nuclei and nuclear phenomena, which can be a useful mean during the teaching of nuclear physics. Even though such macroscopic models are unable to depict the true quantum physical nature of nuclear processes, they can be much more useful didactically than the previously used disordered sets of balls, to represent the atomic nucleus.
Khaled Sh. Azab, Nefissa H. Meky, Eglal A. M. El-Deghidy, Ghada Azoz
World Journal of Nuclear Science and Technology, Volume 07, pp 189-205; https://doi.org/10.4236/wjnst.2017.73016

Abstract:
Background: Systemic inflammation due to radiation exposure has been identified in a biological system by certain metabolic and behavioral disorders. These anarchies mostly mediated under a regulation of cyclooxygenase 2 (COX2) induced production of an inflammatory mediator prostaglandin E2 (PGE2). Aim: This study was undertaken to investigate the anti-inflammatory impact of brown sea weed extract (BSWE) against induction of COX2/PGE2 inflammatory pathway in gamma-irradiated rats. Rats were orally administrated with BSWE (27 mg/kg body weight/day) for 7 consecutive days before exposure to 8 Gy fractionated gamma radiation (2 Gy × 4; every 3 days). Treatment with BSWE was extended along with and in-between irradiation doses for another 14 successive days. Our data demonstrated that the administration of BSWE to rats exposed to gamma radiation, following the regimen suggested, significantly neutralize the changes induced in the inflammatory molecules COX2, PGE2, tumor necrosis alpha (TNF-α), and nitric oxide (NO). In addition, it adjusted significantly the cellular redox tone via regulation of changes induced in malondialdehyde (MDA) reduced glutathione (GSH), superoxide dismutase (SOD) catalase (CAT) and xanthine oxidoreductase system (XOR). Credibly, from the results emerged in this study, it could be suggested that BSWE has substantial anti-inflammatory activities and gamma radiation protection capabilities. It is recommended to include BSWE in the treatment strategy of various inflammatory diseases especially cancer as a safe natural anti-inflammatory agent.
, Delvonei Alves de Andrade
World Journal of Nuclear Science and Technology, Volume 07, pp 167-188; https://doi.org/10.4236/wjnst.2017.73015

Abstract:
This work proposed the application of system engineering methods to identify organizations vital for society, seeking development and well-being. System engineering requires the identification of blocks (or systems), identification of their service functions, identification of states, identification of required quality and identification of constraints. Analyzing modern societies, vital functions were identified and countries behavior was modeled, identifying their states. In this context, nuclear power was found to be fundamental for development and defense because of its inherent advantages for military naval purposes at war. Another striking conclusion is that nuclear power is the best solution for country energy security, more than to avoid climate changes, but to help the nation to resist climate changes. A solution to mitigate the high overnight costs of nuclear power was also proposed. It was demonstrated qualitatively that the adoption of dual purpose mobile nuclear power plants military performances, economic development and risks management.
, Olair dos Santos, Elita Fontenele Urano de Carvalho, Humberto Gracher Riella,
World Journal of Nuclear Science and Technology, Volume 07, pp 155-166; https://doi.org/10.4236/wjnst.2017.73014

Abstract:
IEA-R1 nuclear reactor operation has the routine to control uranium content in pool water to be in trace range below 50 µg/L. There are several routes to determine the uranium trace content in water in the literature; voltammetry has been systematically employed. In the present study, the chosen chemical determination of uranium traces used the voltammetric method known as AdCSV (adsorptive cathodic stripping voltammetry). This technique, based on mercury voltammetry, is an adequate methodology to determine uranium traces. The chloranilic acid [CAA] (2,5-dichloro-3,6-dihydroxy-1,4-benzo- quinone) is indicated as chelating agent. The redox reaction of with CAA is sensitive in the range of 2 < pH < 3. But pH variation imposes changing on [UO2(CAA)2] reduction potential. In this work, we present the uranium trace results for IEA-R1 reactor water, sampled after an operation routine shutdown. The uranium trace determination for IEA-R1 pool water showed content around 1 µg/L [U] with statistical significance. Therefore the IEA-R1-reactor-water purification showed to be adequate and safe.
N. Jahan, M. M. Rahman, M. Q. Huda
World Journal of Nuclear Science and Technology, Volume 07, pp 145-154; https://doi.org/10.4236/wjnst.2017.73013

Abstract:
A design for instantaneous neutron flux signal acquisition system is being carried out for reactivity measurement of the nuclear research reactor. It is a computer-based digital data acquisition system that can perform continuous monitor and measurement of reactivity inserted into or removed from the research reactor. The acquisition system accomplishes with two major parts. The first part is an interfacing PCI based data acquisition card and the corresponding driver software intending to on-line acquisition of neutron flux signals from plant instrumentation channel. The second part incorporates the high-level Visual Basic real time program, indigenously developed for computation of reactivity by the solution of neutron point kinetic equations and other relevant functional modules like input file logging, reactivity calculation, graphics demonstration etc.
Jamilah Al-Zahrani
World Journal of Nuclear Science and Technology, Volume 07, pp 136-144; https://doi.org/10.4236/wjnst.2017.73012

Abstract:
The concentrations of natural radioactivity were measured in igneous rock samples collected from Albaha region in the south west of Saudi Arabia. A high purity germanium (HPGe) detector was used for analysis. The average activity concentrations for 226Ra, 232Th and 40K were 35, 31.52 and 843.63 Bq kg−1, respectively. The average absorbed dose rate was 70.86 nGy⋅h−1 with a corresponding average annual effective dose 0.09 mSv⋅y−1. The average radium equivalent activity value was 145.84 Bq⋅kg−1, lower than the international limit 370 Bq⋅kg−1. The external and internal indices average values were 0.39 and 0.49, respectively. The average results obtained in this study are lower than the average national and world recommended values, therefore, there is no health risk to the populace of the area. This study provides a baseline map of background radioactivity levels in the Saudi environment and will be used as reference information to assess any changes in the level background due to geological processes.
N. Jahan, M. M. Rahman, M. Q. Huda, S. M. Seo
World Journal of Nuclear Science and Technology, Volume 07, pp 129-135; https://doi.org/10.4236/wjnst.2017.73011

Abstract:
In reactor physics tests, it is important to monitor sub-criticality continuously during criticality approach. Reactivity measurements by the inverse kinetics method are widely used during the operation of a nuclear reactor. This technique is successfully applied at sufficiently high power level or to a core without an external neutron source where the neutron source term in point reactor kinetics equations may be neglected. For operation at low power levels or in the sub-critical domain, the increase in the fluctuation of the neutron signal may cause difficulties in the evaluation of reactivity and the effect of direct emission from the external neutron source may not be neglected. Therefore, contribution of the neutron source must be taken into account and this implies knowledge of a quantity proportional to the source strength, which calls the source term and then it should be determined. The research work has been conducted to measure reactivity with source term using a dedicated reactivity measurement system by the Least Square Inverse Kinetics Method (LSIKM). Application to a simulator of HANARO research reactor, Korea Atomic Energy Research Institute (KAERI), with known source strength and reactivity worth has showed consistent and satisfactory agreement.
Osama Ahmed, Farouk I. Habbani, A. M. Mustafa, E. M. A. Mohamed, A. M. Salih, Ftihia Seedig
World Journal of Nuclear Science and Technology, Volume 07, pp 121-128; https://doi.org/10.4236/wjnst.2017.72010

Abstract:
The aim of this study is a quality assessment of X-ray fluorescence laboratory located at the University of Khartoum. The X-ray fluorescence spectrometer system consists, a set of three 109Cd sources of an initial nominal activity of 10 μCi, and Si(Li) detector Energy Dispersive XRF(EDXRF) systems. It is important to carry out this work because it has an effective contribution for a wide range of research and services. The assessment was carried out by measuring 8 NIST-2709a (soil) and 13 IAEA-155 (milk powder) standard reference material samples for repeatability examinations to test the measurement precision. The total combined standards uncertainty values for XRF lab were estimated by an error from repeatability measurements adding 2.6% for error propagation related to the method. For accuracy assessment, three standard statistic approaches were applied, i.e. the Bias %, zeta-score, and En-number. The bias of all elements for both standard materials was found to be within a deviation range from −28% to 7.8%. The results of all elements for both the zeta-score test and En-number have satisfactory results except Th (Thorium) and Zr (Zirconium) which consider as questionable results for NIST SRM 2709a and unsatisfactory results for En-number.
, Alessandro Da Cruz Gonçalves, Zelmo Rodrigues de Lima
World Journal of Nuclear Science and Technology, Volume 07, pp 103-120; https://doi.org/10.4236/wjnst.2017.72009

Abstract:
The main purpose of this paper is to perform a numerical analysis of the Neutron Spatial Kinetic Equations, subject to transients of the External Neutron Source, by applying the Implicit Euler Method as well as the Runge-Kutta Method in order to check which methods are best applicable in transients caused by External Neutron Source. For this purpose, a one-dimensional ADS reactor with a constant external source was simulated based on the geometry of ANL-BSS-6 reactor for benchmark effects.
Wenhui Lv, Huiping Guo, Ning Lv, Chenyang Tian, , Xiaotian Wang, Yijie Hou
World Journal of Nuclear Science and Technology, Volume 07, pp 93-102; https://doi.org/10.4236/wjnst.2017.72008

Abstract:
The real-time monitoring of environmental radiation dose for nuclear fa-cilities is an important part of safety, in order to guarantee the accuracy of the monitoring results regular calibration is necessary. Around nuclear facilities there are so many environmental dosimeters installed dispers-edly, because of its huge quantity, widely distributed, and in real-time monitoring state; it will cost lots of manpower and finance if it were tak-en to calibrate on standard laboratory; what’s more it will make the en-vironment out of control. To solve the problem of the measurement ac-curacy of the stationary gamma radiation dosimeter, an on-site calibra-tion method is proposed. The radioactive source is X-ray spectrum, and the dose reference instrument which has been calibrated by the national standard laboratory is a high pressure ionization. On-site calibration is divided into two parts; firstly the energy response experiment of dosim-eter for high and low energy is done in the laboratory, and the energy response curve is obtained combining with Monte Carlo simulation; sec-ondly experiment is carried out in the field of the measuring dosimeter, and the substitution method to calibrate the dosimeter is used; finally the calibration coefficient is gotten through energy curve correction. In order to verify the accuracy of on-site calibration method, the calibrated dosimeter is test in the standard laboratory and the error is 3.4%. The re-sult shows that the on-site calibration method using X-ray is feasible, and it can improves the accuracy of the measurement results of the stationary γ-ray instrument; what’s more important is that it has great reference value for the radiation safety management and radiation environment evaluation.
Jerrad P. Auxier, John D. Auxier Ii,
World Journal of Nuclear Science and Technology, Volume 07, pp 84-92; https://doi.org/10.4236/wjnst.2017.72007

Abstract:
Although the eminent threat of a terrorist group detonating an improvised nuclear device (IND) in an urban environment is low, it is crucial that countries develop modern nuclear forensic capabilities to expedite response in a post-detonation scenario. In particular, new instruments need to be created to shorten dissolution time, expedite chemical separation, and improve forensic analysis of the nuclear melt glass that is created during the detonation of the device. To expedite this process, an instrument was designed to thermally couple a gas chromatograph (GC) to a time-of-flight inductively coupled plasma time-of-flight mass spectrometer (ICPTOFMS) In order to couple these two instruments, another instrument was designed to provide an isothermal atmosphere between the GC and TOFICPMS to expedite rapid gas separations processes. By using gas separations instead of the current wet chemistry processes, the required separation and analysis time of the melt glass significantly decreases. The new instrument would also provide a more detailed analysis of the elemental and isotopic composition of the melt glass. By completing these tasks simultaneously, this significantly decreases the required time to conduct these separations and improves the elemental and isotopic analysis.
Ali A. Alzubadi, Duaa Majid Hameed
World Journal of Nuclear Science and Technology, Volume 07, pp 67-83; https://doi.org/10.4236/wjnst.2017.72006

Abstract:
The nuclear structure for some target nuclei namely: 32S, 58Ni, 89Y, 90Zr, 100Mo and 197Au used for production of the therapeutic radionuclides; 32P, 58Co, 89Sr, 90Y, 99Mo, 100Tc, 197Pt and 197Hg has been investigated using Skyrme-Hartree-Fock method based on Skyrme effective two-body interaction. For these purpose, we have calculated the various nuclear densities, the corresponding root mean square radii and nuclear binding energies. The density dependent initial neutron and proton exciton numbers have been also calculated which give the ability to investigate the neutron and proton induced reaction cross-sections for these target nuclei using hybrid model for pre-equilibrium nuclear reactions. The calculated results are compared with available experimental data.
Nguyen An Son, Nguyen Duc Hoa, Tran Trung Nguyen, Tran Quoc Tuan, Osvaldo Camueje Raul
World Journal of Nuclear Science and Technology, Volume 07, pp 15-23; https://doi.org/10.4236/wjnst.2017.71002

Abstract:
Control rod is used to change the power in nuclear reactor. Certainly, the core at any moment can be made subcritical condition and shut downs when occurring to emergency instance in the core. The rod is grouped based on their function and located at different places in the core where their feature is maximized. Two methods of control rod calibration are the asymptotic period method and the rod-drop method, which were applied in this experiment. In the first method, the reactor is made supcritical by inserting the control rod to be calibrated a certain level. The rod drop method is to determine the subcritical; at the critical state, the rod to be calibrated is dropped into the core, and the resulting decay of neutron flux is observed and related to the reactivity. In this paper, the regulating rod will be calibrated according to the reactivity in OPR-1000 that corresponds to a certain control rod insert or withdraw, and the reactivity in power reactor depends on the integral and differential control rod group too. The core simulator OPR1000 is used to test those methods.
Rubina Nasir, , Nasir M. Mirza
World Journal of Nuclear Science and Technology, Volume 07, pp 24-34; https://doi.org/10.4236/wjnst.2017.71003

Abstract:
Effect of flow rate perturbations has been studied using the modified computer program CPAIR-P for time dependent corrosion rates in Pressurized Water Reactors (PWRs) having extended cycles. In these simulations, a decrease in the corresponding saturation values of corrosion product activity (CPA) is observed for higher pH values. Comparison of CPA’s behavior has been done for constant flow-rate case as well as for transients with elevated 10B levels (~40%) in dissolved boric acid in coolant in two operating cycles. When the flow rate is decreased in the first cycle, the saturation value of CPA attains new higher values. Also, in the second operating cycle, the saturation values are about 12% higher when compared with the values in the first cycle.
Kyeongmo M. Hwang, Hyeok Kee Seo, Chan Kyu Lee, Won Chang Nam
World Journal of Nuclear Science and Technology, Volume 07, pp 1-14; https://doi.org/10.4236/wjnst.2017.71001

Abstract:
It has been thought that wall thinning on the secondary side piping in nu-clear power plants is mostly caused by Flow-Accelerated Corrosion (FAC). Recently, it has been seen that wall thinning on the secondary side piping carrying two-phase flow is caused by not only FAC but also Liquid Droplet Impingement Erosion (LDIE). Moreover, it turns out that LDIE in nuclear power plants does not result from a single degradation mechanism but also from the simultaneous happenings of LDIE and FAC. This paper presents a comparison of the mass loss rate of the tested materials between carbon steel (A106 B) and low alloy steel (A335 P22) resulting from degradation effect. An experimental facility was set up to develop a prediction model for clarifying multiple degradation mechanisms that occur together. The experimental facility allows examining liquid droplet impingement erosion in the same conditions as the secondary side piping in nuclear power plants by generating the magnetite on the surface of the test materials. The magnetite is formed by controlling the water chemistry and the temperature of fluid inside the facility. In the initial stage of the experiments, the mass loss rate of A106 B was greater than that of A335 P22. However, after a certain period of time, the mass loss rate of A335 P22 became greater than that of A106 B. It is presumed that the results are caused by the different yield strengths of the test materials and the different degrees of buffer action of the magnetite deposited on their surfaces. The layer of magnetite on the surface of A106 is thicker than that of A335 P22, due to the different amount of chrome content. In nuclear power plants, carbon steel piping having experienced wall thinning degradation is generally replaced with low-alloy steel piping. However, the materials of pipes carrying two-phase flow should be selected considering their susceptibility to LDIE.
Bernard Schaeffer
World Journal of Nuclear Science and Technology, Volume 06, pp 199-205; https://doi.org/10.4236/wjnst.2016.64021

Abstract:
After one century of nuclear physics, its underlying fundamental laws remain a puzzle. Rutherford scattering is well known to be electric at low kinetic energy. Nobody noticed that the Rutherford scattering formula works also at high kinetic energy, needing only to replace the repulsive electric -2 exponent by the also repulsive magnetic -6 exponent. A proton attracts a not so neutral neutron as amber attracts dust. The nucleons have magnetic moments that interact as magnets, equilibrating statically the electric attraction between a proton and a not so neutral neutron. In this paper, the electromagnetic potential energies of the deuteron 2H and the α particle 4He have been calculated statically, using only electromagnetic fundamental laws and constants. Nuclear scattering and binding energy are both electromagnetic.
Aziz Boukhair, Laila Belahbib, Khadija Azkour, , Mohammed Benjelloun, Abdelmjid Nourreddine
World Journal of Nuclear Science and Technology, Volume 06, pp 206-216; https://doi.org/10.4236/wjnst.2016.64022

Abstract:
The radiological impact of coal ashes, with enhanced natural radioactivity in the storage site, is due to the presence of naturally occurring radionuclides. Some of these radionuclides have a radioactive period of several million years and will, therefore, have time to migrate to the soil, atmospheric air, surface water, and groundwater. This impact depends mainly on the activity of these coal ashes, the duration of exposure to such waste, transfers to the air, and the leaching phenomenon by rainwater. In this study, and so as to assess the radiological impact of coal ashes of the storage site of the JLEC-Morocco thermal power plant on environment, some analyses are performed by alpha dosimetry and a digital dosimeter on samples of coal ashes, soil, atmospheric air, surface water and groundwater belonging to a perimeter of 10 km around that site. The obtained results show that, within the studied area, the radiological impact on the soil of the coal ashes of the storage site is insignificant even though the concentrations of radon in the near vicinity (1 to 2 km) are moderately important, and remain below 200 Bq/m3. In the atmospheric air, this impact remains medium for the neighborhoods of the storage site (2 to 3 km) with radon activities superior to 10 Bq/m3. These results also show that there may be a water contamination of wells located at the storage site without any transfer of radioactivity into the groundwater of the area studied where the concentrations of radon are less than 11.1 Bq/l.
Saverio Braccini, Karl Krämer, Stephane Chapenoire
World Journal of Nuclear Science and Technology, Volume 06, pp 191-198; https://doi.org/10.4236/wjnst.2016.64020

Abstract:
Natural magnetic black sands are known from several sites often located in areas of volcanic origin. Their elemental and mineral composition provides information on the geology of their territory and depends on several factors occurred during their formation. A sample of black sand was collected on the seashore of the island of Mayotte in the Indian Ocean and its magnetic part was investigated by means of energy dispersive X-ray spectroscopy (EDS), powder X-ray diffraction (XRD), and MÖssbauer spectroscopy at room temperature. The mineral composition is dominantly magnetite, in good agreement with samples collected in other sites of volcanic origin. Contrary to pure magnetite, a relevant fraction of Ti was detected by EDS. The 16% Ti and 1% Mn content increase the magnetite lattice parameter to 8.4312 (25) Å. The broadening of XRD lines pointed towards a significant degree of disorder. This was confirmed by MÖssbauer spectroscopy and is attributed to the presence of Ti replacing Fe in the magnetite lattice. The presence of Ti modifies the local magnetic field on the Fe sites, leading to a broader and more complex MÖssbauer transmission spectrum with respect to the one of pure magnetite. To study the effect of temperature, samples were heated for 12 hours to 600°C and 800°C in argon and to 1000°C in air. Annealing in argon did not improve the crystallinity while annealing in air caused a complete decomposition of magnetite into hematite and pseudobrookite.
Miguel Luiz Miotto Negro, , Marco Aurélio de Mesquita, Elita Fontenele Urano de Carvalho, Delvonei Alves de Andrade
World Journal of Nuclear Science and Technology, Volume 06, pp 217-231; https://doi.org/10.4236/wjnst.2016.64023

Abstract:
Several fuel plants that supply nuclear research reactors need to increase their production capacity in order to meet the growing demand for this kind of nuclear fuel. After the enlargement of the production capacity of such plants, there will be the need of managing the new production level. That level is usually the industrial one, which poses challenges to the managerial staff. Such challenges come from the fact that several of those plants operate today on a laboratorial basis and do not carry inventory. The change to the industrial production pace asks for new actions regarding planning and control. The production process based on the hydrolysis of UF6 is not a frequent production route for nuclear fuel. Production planning and control of the industrial level of fuel production on that production route is a new field of studies. The approach of the paper consists in the creation of a mathematical linear model for minimization of costs. We also carried out a sensitivity analysis of the model. The results help in minimizing costs in different production schemes and show the need of inventory. The mathematical model is dynamic, so that it issues better results if performed monthly. The management team will therefore have a clearer view of the costs and of the new, necessary production and inventory levels.
Jianyong Zhang, Xiao Cai, Xiaohu Mochizuki, Muchnoi Nickolai, Achasov Mikhail, Elena Abakumova, Harris Fred
World Journal of Nuclear Science and Technology, Volume 06, pp 261-283; https://doi.org/10.4236/wjnst.2016.64025

Abstract:
The beam energy measurement system is significant and profit for both BES-III detector and BEPC-II accelerator. The detection of the high energy scattering photons is realized by virtue of the Compton backscattering principle. Many advanced techniques and precise instruments are employed to acquire the highly accurate measurement of positron/electron beam energy. During five years’ running period, in order to satisfy the requirement of data taking and enhance the capacity of measurement itself, the upgradation of system is continued, which involves the components reformation of laser and optics subsystem, replacement of view-port of the laser to vacuum insertion subsystem, the usage of electric cooling system for high purity germanium detector, and the refinement of data acquisition and processing subsystem. The upgrading of system guarantees the smooth and effective measuring of beam energy at BEPC-II and accommodates the accurate offline energy values for further physics analysis at BES-III.
M. P. Silverman
World Journal of Nuclear Science and Technology, Volume 06, pp 232-260; https://doi.org/10.4236/wjnst.2016.64024

Abstract:
A simple method employing a pair of pancake-style Geiger-Mueller (GM) counters for quantitative measurement of radon activity concentration (activity per unit volume) is described and demonstrated. The use of two GM counters, together with the basic theory derived in this paper, permit the detection of alpha particles from decay of and progeny ( 218Po, 214Po) and the conversion of the alpha count rate into a radon concentration. A unique feature of this method, in comparison with standard methodologies to measure radon concentration, is the absence of a fixed control volume. Advantages afforded by the reported GM method include: 1) it provides a direct in-situ value of radon level, thereby eliminating the need to send samples to an external testing laboratory; 2) it can be applied to monitoring radon levels exhibiting wide short-term variability; 3) it can yield short-term measurements of comparable accuracy and equivalent or higher precision than a commercial radon monitor sampling by passive diffusion; 4) it yields long-term measurements statistically equivalent to commercial radon monitors; 5) it uses the most commonly employed, overall least expensive, and most easily operated type of nuclear instrumentation. As such, the method is par-ticularly suitable for use by researchers, public health personnel, and home dwellers who prefer to monitor indoor radon levels themselves. The results of a consecutive 30-day sequence of 24 hour mean radon measurements by the proposed GM method and a commercial state-of-the-art radon monitor certified for radon testing are compared.
Vladimir Petrochenko, Georgy Toshinsky, Oleg Komlev
World Journal of Nuclear Science and Technology, Volume 06, pp 284-300; https://doi.org/10.4236/wjnst.2016.64026

Abstract:
The conflict between safety and economics requirements is peculiar to the present nuclear power (NP). The main point of the conflict is that for traditional type reactors the increase of requirements to safety of nuclear power plants (NPP) worsens their economical characteristics. This is caused by large potential energy accumulated in reactor coolant. In the presented paper the opportunity and expediency of changeover to reactors with heavy liquid-metal coolants (HLMC) in future NP is grounded. First of all, this refers to lead-bismuth coolant (LBC) mastered in the process of operating nuclear submarines (NS) reactors. The reactor facilities (RFs) of that type cannot cause destruction of defense barriers and make possible deterministic elimination of severe accidents with catastrophic radioactivity release. So it will make possible to eliminate the highlighted conflict and reasons for existence of population’s radiophobia. Lead-bismuth fast reactor SVBR-100 with electric power of 100 MWe is the reactor facility of that type. The effect of accumulated in coolant potential energy on safety and economics is considered. Main specific features of SVBR-100 technology providing a high level of inherent self-protection and passive safety are presented.
, Delvonei Alves de Andrade
World Journal of Nuclear Science and Technology, Volume 06, pp 309-319; https://doi.org/10.4236/wjnst.2016.64028

Abstract:
This work aimed at proposing a new combination of technologies to improve military performances and reduce costs of nuclear attack submarines, without overlooking safety constraints. The last generation of nuclear attack submarines increased size to meet safety and operational requirements, imposing huge burden on costs side, reducing fleet size. The limitations of current Technologies employed were qualitatively discussed, explaining their limitations. There are new technologies (plate and shell heat exchangers) and architectural choices, like passive safety, and segregation of safety and normal systems, which may lead to reduction of costs and size of submarines. A qualitative analysis was provided on this combination of technologies, stressing their commercial nature and maturity, which reduced risks. The qualitative analysis showed the strong and weak points of this proposal, which adopted the concept of strength in numbers. Concluding, new Technologies enabled the existence of 3800 t nuclear attack submarines with powerful propulsion systems and good acoustic discretion.
Raquel Dalledone Siqueira da Cunha, Delvonei Alves de Andrade
World Journal of Nuclear Science and Technology, Volume 06, pp 301-308; https://doi.org/10.4236/wjnst.2016.64027

Abstract:
The presence of a potentially hazardous facility in a community demands several safety procedures. Bringing risk communication among those actions may help the population that lives near the facility feel more confident and have the required knowledge on how to behave in an emergency situation. A research performed in Angra dos Reis, RJ, Brazil, where a nuclear power plant is located, shows that there is a lack of information and awareness about the emergency plan.
K. Rusiecka, A. Wrońska, P. Bednarczyk, D. Böckenhoff, A. Bubak, S. Feyen, L. Kelleter, A. Konefał, K. Laihem, J. Leidner, et al.
World Journal of Nuclear Science and Technology, Volume 06, pp 63-70; https://doi.org/10.4236/wjnst.2016.61006

Abstract:
An experiment investigating gamma emission in hadron therapy was performed at Cyclotron Centre Bronowice (CCB), Cracow, Poland, using two different phantom materials—carbon and poly(methyl methacrylate) PMMA. The measurements were carried out at 70 MeV proton beam energy and the gamma quanta were registered with the use of HP Ge detector with scintillation anti-Compton shielding. Although the primary aim was to establish a solid experimental data base for future applications in prompt gamma imaging, the data have also been analyzed with regards to the position and shape of the spectral line stemming from deexcitation of the carbon excited state 4.44 MeV. Measurements potentially useful to determine the cross section were performed only at 90° laboratory polar angle. However, benefiting from the very good energy resolution it turned out possible to extract information on angular distribution of the C* (4.44 MeV) deexcitation by analyzing the associated line shape. This paper presents the scheme of model calculations assuming the whole process can be divided into two stages: excitation of carbon nuclei by impinging protons and deexcitation of the C* (4.44 MeV) state.
Alejandro I. Lazarte, J. C. Ferreri
World Journal of Nuclear Science and Technology, Volume 06, pp 170-190; https://doi.org/10.4236/wjnst.2016.63019

Abstract:
Previous analytical results on flow splitting are generalized to consider multiple boiling channels systems. The analysis is consistent with the approximations usually adopted in the use of systems codes (like RELAP5 and TRACE5, among others) commonly applied to perform safety analyses of nuclear power plants. The problem is related to multiple, identical, parallel boiling channels, connected through common plena. A theoretical model limited in scope explains this flow splitting without reversal. The unified analysis performed and the confirmatory computational results found are summarized in this paper. New maps showing the zones where this behavior is predicted are also shown considering again twin pipes. Multiple pipe systems have been found not easily amenable for analytical analysis when dealing with more than four parallel pipes. However, the particular splitting found (flow along N pipes dividing in one standalone pipe flow plus N -1 identical pipe flows) has been verified up to fourteen pipes, involving calculations in systems with even and odd number of pipes using the RELAP5 systems thermal-hydraulics code.
Akif Mohammed, Gordon Jacobsen, Karthik Ananthasubramaniam
World Journal of Nuclear Science and Technology, Volume 06, pp 161-169; https://doi.org/10.4236/wjnst.2016.63018

Abstract:
Background: Altered myocardial sympathetic innervation activity (AMSI) is known to be present in systolic heart failure patients (SHF) and recently SPECT imaging using I-123 mIBG heart to mediastinum (H/M) ratio <1.6 has been shown to predict MACE in the ADMIRE-HF trial. Left ventricular mechanical dyssynchrony (LVMD) is known to be present in a substantial number of SHF patients and has been studied mainly to guide CRT therapy. Recently gated SPECT has shown promise to provide an accurate assessment of LVMD. It remains unclear how the combination of AMSI and LVMD collectively affect clinical outcomes and other cardiovascular parameters. Objectives: The objectives are to examine the clinical characteristics and incremental prognostic value for MACE of LVMD determined by SPECT in SHF patients with or without abnormal cardiac MIBG uptake (H/M ratio < 1.6). Methods: Out of 30 SHF patients who participated from our institution in the ADMIRE-HF trial studying MIBG based AMSI, we included 22 patients with abnormal MIBG H/M ratio of <1.6. We performed gated SPECT LVMD analysis on these patients using the Emory Cardiac Toolbox. The 2 SPECT variables for LVMD assessed were histogram bandwidth and phase standard deviation both of which assess the extent of dispersion of LV activation during contraction as a marker of LVMD. Patients were followed up for a mean period of 6 years. The primary end point was mortality from any cause and secondary end point was heart failure admission or myocardial infarction or ICD shock. Results: 2 Groups were defined: Group A: n = 17 with H/M MIBG ratio < 1.6 and +LVMD and Group B, n = 5 H/M MIBG ratio < 1.6 and −LVMD. Baseline characteristics, cardiac risk factors and medications were comparable between both groups. LVEF was lower and RBBB was less common in Group A. There was no statistical difference in achievement of primary or secondary end points in the two groups including death heart failure readmissions, ICD shocks or MI. Conclusions: In our pilot study, we did not find definitive value of adding SPECT based LVMD to abnormal cardiac MIBG imaging in SHF patients with regards to predicting outcomes. Although our sample size is too small to make any definitive conclusions, it is possible that LVMD works independently through different pathways in the progression of SHF and hence may not necessarily add incremental value to AMSI determination using MIBG.
Aziz Boukhair, Laila Belahbib, Khadija Azkour, , Mohammed Benjelloun, Abdelmjid Nourreddine
World Journal of Nuclear Science and Technology, Volume 06, pp 153-160; https://doi.org/10.4236/wjnst.2016.63017

Abstract:
Coal is the main energy source for electricity generation in the world. In Morocco, 37% of electricity generation comes from combustion coal in thermal power plants. This combustion process generates large amounts of fly and bottom ashes. In recent years, these ashes became a great topic of interest because of their different uses and especially in construction materials. In this work, we assess radiation risks due to natural radioactivity in samples of fly and bottom ashes collected from JLEC (Jorf Lasfar Energy Company) thermal power plant, and different analyses are performed through two nuclear techniques such as gamma spectrometry and alpha dosimetry based on the use of LR115 films detectors. Our analysis shows that 226Ra activities and 232Th in both ash samples are well above the permissible activity. The values of the external risk index (Hex) and internal one (Hin) for these ashes are below unity, with the exception of 1.28 in fly ash for Hin. The obtained values for the equivalent radium Raeq and annual effective doses Ė in fly and bottom ashes are 324 Bq/kg and 210 Bq/kg, and 0.18 mSv/y and 0.11 mSv/y, respectively. The surface radon exhalation rates for the samples of fly and bottom ashes are 276 mBq⋅m-2⋅h-1 and 381 mBq⋅m-2⋅h-1, respectively. Based on these results, we have shown that fly ash and bottom one from thermal power plant JLEC didn’t have, in any case, a health risk to the public so it can be effectively used in various construction activities.
Abdelrazig Mohmed Abdelbagi
World Journal of Nuclear Science and Technology, Volume 06, pp 140-146; https://doi.org/10.4236/wjnst.2016.63015

Abstract:
The main goal of the current study was to determine the fluorine in the rock samples coal (SARM-18, SARM-19, and SARM-20), opal glass NBS91 and phosphate rock NBS694 using neutron activation analysis. Neutrons energy of 14 MeV used for irradiation was produced by bombardment of a water-cooled titanium tri-tide target with a beam of deuterons accelerated to a potential of 350 KV to develop a neutron flux (108 n⋅cm-2⋅s-1) on the sample at the neutron generator in the ECN (Netherlands Energy Research Foundation) Petten. This new approach contributes to the existing knowledge of fluorine measurement by the coincidence channels investigation of the positron energy with respect to decay time for each radionuclide element. The present study was designed to determine the fluorine by fast neutron through the reaction of F19 (n, 2n) F18. Interference was treated by irradiating the standard of these elements and reasonable selection of the decay time between the end of irradiation and beginning of counting time. The results of this method indicate that the concentration of fluorine is agreed fairly with literatures.
Faustino Menegus
World Journal of Nuclear Science and Technology, Volume 06, pp 147-152; https://doi.org/10.4236/wjnst.2016.63016

Abstract:
A more compact representation of the Segré chart of nuclides can be obtained replacing the isotopic neutron with the corresponding neutron excess number; a first sight inspection of all the natural isotopes is produced. The resulting representation shows a built-inorder in the organization of the nuclear components into the nuclei of the natural isotopes, sustained by the relevant role of the magic numbers. The interpretation, on the identical foot, of the nuclear instability of Tc, Pm and of the elements following Bi is suggested. The present representation reminds the spheron model of the nuclear structure suggested by L. Pauling. The alpha decay paths of radioactive isotopes are shown, side by side to the low energy nuclear transmutations (LENR). Representations of the artificial isotopes of the chemical elements and of the stellar nucleosynthesis processes are also proposed.
Pedro Orrego, José Hernández, Jorge Manríquez
World Journal of Nuclear Science and Technology, Volume 06, pp 131-139; https://doi.org/10.4236/wjnst.2016.63014

Abstract:
This article shows the modeling of a uranium dioxide production reactor using COMSOL Multiphysics software program in its 4.3b version. The model was made using 3 kinds of studies: momentum, heat and mass transport, in order to determine the influence of the most important operational parameters: UO3 reaction rate, composition and flow of the reduction gas, the initial temperature reactor and the reducing gas. The operational parameters evaluated were the followings: constant gas flow of2.5 L/min, initial hydrogen concentration of 0.25, 0.50 and0.75 M, and initial temperature of 400°C. The obtained results allow to conclude that under these working conditions, uranium dioxide is obtained virtually instantaneous and, with concentrations close to 0.5 M H2 in the reducing gas, the process can operate continuously and autogenously, without applying additional energy and temperatures around 600°C.
B. Vasundhara, P. Tejeswararao
World Journal of Nuclear Science and Technology, Volume 06, pp 125-130; https://doi.org/10.4236/wjnst.2016.63013

Abstract:
Measurements of K-shell mass attenuation coefficients are reported for the first time in Arsenic oxide (As2O3). Experiments are performed using Arsenic Oxide extended range HPGe detector. To achieve measurements at many small and regular energy intervals, secondary X-ray emission technique using “Seventeen Scatters” is employed. The results are in agreement with the proposed theoretical estimates. No evidence could, however be gained in favor of microscopic theories such as RRS and EXAFS, insofar as there are no energy points within a range of 100eV on either side of the K-edge.
K. S. Al-Mugren, Mahmoud I. Abbas, Eman M. El-Bayoumi, N. S. Aly
World Journal of Nuclear Science and Technology, Volume 06, pp 115-124; https://doi.org/10.4236/wjnst.2016.62012

Abstract:
In this paper full-energy peak (photopeak) efficiency and photopeak attenuation coefficient of 3'' × 3'' NaI(Tl) well-type scintillation detector were calculated using gamma-rayisotropic radiating point sources (with photon energy: 0.245, 0.344, 0.662, 0.779, 0.964, 1.1732, 1.333 and 1.408 MeV) placed outside the detector well. These energies were obtained from 152Eu, 137Cs and 60Co. The relations between the full energy peak efficiency and photopeak attenuation coefficients, were plotted vs. photon energy at different sources to detector distance, and it found that the full energy peak efficiency decreased by increasing the distance between the source and the detector.
, Luping Zhang, Daniel Bondarenko, C. A. Barry Stoute
World Journal of Nuclear Science and Technology, Volume 06, pp 103-114; https://doi.org/10.4236/wjnst.2016.62011

Abstract:
The paper builds the high-current plasma beams model under different dimensions (1D, 2D, and 3D) by continuum (magnetohydrodynamics MHD) and statistical (Monte Carlo MC) mechanics under conditions of low pressures (10-3 Pa). After detailed presentation of the model, two methods firstly have been analyzed in terms of plasma beam properties. Then, we compare the simulation results of MHD numerical simulation with MC stochastic particles simulation. Finally, through further analysis, it is demonstrated that integrated hybrid MHD and MC method (IMHDMC) provides an innovative practical tool to capture essential properties of high-current plasma beams.
Bernard Schaeffer
World Journal of Nuclear Science and Technology, Volume 06, pp 96-102; https://doi.org/10.4236/wjnst.2016.62010

Abstract:
After one century of nuclear physics, the anomalous Rutherford scattering remains a puzzle: its underlying fundamental laws are still missing. The only presently recognized electromagnetic interaction in a nucleus is the so-called Coulomb electric force, in 1/r, only positive thus repulsive in official nuclear physics, explaining the Rutherford scattering at low kinetic energy of the impacting alpha particles. At high kinetic energy the Rutherford scattering formula doesn’t work, thus called “anomalous scattering”. I have discovered that, to solve the problem, it needs only to replace, at high kinetic energy, the Coulomb repulsive electric potential in 1/r, by the also repulsive magnetic Poisson potential in 1/r3. In log-log coordinates, one observes two straight lines of slopes, respectively −2 and −6. They correspond with the −1 and −3 exponents of the only repulsive electric and magnetic interactions, multiplied by 2 due to the cross-sections. Both Rutherford (normal and anomalous) scattering have been calculated electromagnetically. No attractive force needed.
Elassaad Jemii, Lotfi Ghedira
World Journal of Nuclear Science and Technology, Volume 06, pp 89-95; https://doi.org/10.4236/wjnst.2016.62009

Abstract:
The present work presents an overview of the study of some dosimetric quantities in the vicinity of the Tunisian Gamma Irradiation Facility. Firstly, we have confirmed our previous calculation of the photon flux and the dose rates, using a simulation with GEANT 4. A good agreement between calculation and simulation was obtained, which well confirmed the modeling of the CNSTN extended source by a pencil-like source. Secondly we have determined the isodose curves in the vicinity of the irradiator using a straightforward calculation. Finally, we have presented many comments for some published work concerning the methods used to determine these dosimetric quantities.
World Journal of Nuclear Science and Technology, Volume 06, pp 79-88; https://doi.org/10.4236/wjnst.2016.61008

Abstract:
Development and use of nuclear energy is currently growing very rapidly, in order to achieve increasingly advanced technology, both in terms of design, economic factors and safety factors. Thermal-hydraulics aspects of nuclear reactors should be done with calculation and near-perfect condition. Including today began development of a nuclear reactor with low power below 300 MW, or commonly called the Small Modular Reactor (SMR). One is CAREM-25 developed by Argentina with a power of 25 MW, where in CAREM already using natural circulation system and the use of nanofluid as coolant fluid. In this research, analytic modeling of thermal-hydraulics nuclear reactor SMR CAREM-25, when the nanofluid Al2O3-Water used as cooling fluid in the cooling system of a nuclear reactor. Further to this analytic modeling will be done on CFD. Analytic modeling with CFD to determine the flow phenomena and distribution as well as the effect of nano-particles of Al2O3-Water based on the volume fraction (1% and 3%) of the coefficient of heat transfer by natural convection.
, Farhana Sarwar, Syed Mohsin Raza
World Journal of Nuclear Science and Technology, Volume 06, pp 71-78; https://doi.org/10.4236/wjnst.2016.61007

Abstract:
Rutherford classical scattering theory, as its quantum mechanical analogue, is modified for scattering cross-section and the impact parameter by using quantum mechanical momentum, (de Broglie hypothesis), energy relationship for matter oscillator (Einstein’s oscillator) and quantum mechanical wave vectors, and , respectively. It is observed that the quantum mechanical scattering cross-section and the impact parameter depended on inverse square law of quantum action (Planck’s constant). Born approximation is revisited for quantum mechanical scattering. Using Bessel and Neumann asymptotic functions and response of nuclear surface potential barrier, born approximations were modified. The coulombic fields inside the nucleus of the atom are studied for reflection and transmission with corresponding wave vectors, phase shifts and eigenfunctions Bulk quantum mechanical tunneling and reflection scattering, both for ruptured and unruptured nucleus of the atom, are deciphered with corresponding wave vectors, phase shifts and eigenfunction. Similar calculation ware accomplished for quantum surface tunneling and reflection scattering with corresponding wave vectors, phase shifts and eigenfunctions. Such diverse quantum mechanical scattering cross-section with corresponding wave vectors for tunneling and reflection, phase shifts and eigenfunctions will pave a new dimension to understanding the behavior of exchange fields in the nucleus of the atom with insides layers both ruptured and unruptured. Phase shifts, δl for each of the energy profile (partial) will be different and indeed their corresponding wave vectors for exchange energy eigenvalues.
Licia Del Frate, Fabio Moretti, Giorgio Galassi, Francesco D’Auria
World Journal of Nuclear Science and Technology, Volume 06, pp 53-62; https://doi.org/10.4236/wjnst.2016.61005

Abstract:
This paper deals with the inaccuracy assessment of the friction pressure loss estimation based on Darcy formula combined with an equivalent hydraulic diameter and a friction factor valid for circular pipes when applied to a square rod bundle. The assessment has been done by comparing the analytical and semi-empirical predictions with two different CFD codes results: CFX and NEPTUNE_CFD. Two different analytical approaches have been considered: the whole-bundle and sub-channel approaches, both for laminar and turbulent flow conditions. Looking at results, it is reasonable to assume that an error in the range of 11% - 23% is likely when using equivalent diameter in the laminar regime. In the case of turbulent regime, the equivalent diameter works better and the error is in the range between a few percent and ~12%.
Luis Olivares, Jaime Lisboa, Jorge Marin, Mario Barrera, Alberto Navarrete
World Journal of Nuclear Science and Technology, Volume 06, pp 43-52; https://doi.org/10.4236/wjnst.2016.61004

Abstract:
Generally, the atomization of UMo particles is done under vacuum or argon atmosphere, and the surface modification of these UMo particles is, usually, carried on through a further process. The techniques for surface modification of atomized UMo particles, aimed to control the Fuel/Matrix interaction, involve, in some cases, complex methodologies and often with minor effect due to the limited solubility of third elements in solid UMo alloy. The atomization and surface conditioning, applied in separate stages, may affect the efficiency of powder production process. Then, the main goal of this study is to explore the surface modification of UMo particles in liquid state or during the solidification that follows the centrifugal atomization process. Through the change of atomization atmosphere, could be possible to promote liquid/gas reactions, with a higher solubility of the modifier element in micro drops of UMo alloy, before they become solid particles. This paper presents comparative results of centrifugal atomization of UMo particles, carried out under inert argon and reactive nitrogen atmospheres. Dissolved nitrogen contents, measured by SEM-EDS analyses, reached up to 7.57 wt% at the center of under nitrogen atomized particles, very higher than 0.84 wt% of nitrogen measured at the center of UMo particle atomized under argon. The presence of uranium nitride was partially verified by conventional XRD analysis. Nevertheless, Out-of-Pile interaction test result, reveals decreasing of aluminium contents into UMo particles atomized under nitrogen atmosphere; Just 3.77 wt% of Al was the maximum content detected in the center of these particles, very lower than 29.11 wt% of Al measured inside UMo particles atomized under argon. Finally, it is possible to conclude that the atomization under reactive atmosphere may modify the surface composition and the behavior of UMo fuel particles dispersed in aluminium, for dispersion type nuclear fuel application.
Zhi Xu, Daoqing Jiang
World Journal of Nuclear Science and Technology, Volume 06, pp 1-14; https://doi.org/10.4236/wjnst.2016.61001

Abstract:
Westinghouse company (WEC) had developed a Nuclear Regulatory Commission (NRC) approved advanced logic system (ALS) platform based on field programmable gate array (FPGA) technology as the next generation 1E class platform for protection and monitoring system (PMS) development for nuclear power plants. In compliance with the requirements of typical PMS functions, a new ALS based PMS is designed by overcoming the restrictions of communication modules etc. The consistency with data communication independence and isolation, deterministic, diversity requirements etc. is analyzed. The evaluations indicate the design meets the requirements and can be applied for coming projects.
Charles W. Solbrig, Stephen A. Warmann
World Journal of Nuclear Science and Technology, Volume 06, pp 23-42; https://doi.org/10.4236/wjnst.2016.61003

Abstract:
This work investigates an accident during the pyrochemical extraction of Uranium and Plutonium from PWR spent fuel in an argon atmosphere hot cell. In the accident, the heavy metals (U and Pu) being extracted are accidently exposed to air from a leaky instrument penetration which goes through the cell walls. The extracted pin size pieces of U and Pu metal readily burn when exposed to air. Technicians perform the electrochemical extraction using manipulators through a 4 foot thick hot cell concrete wall which protects them from the radioactivity of the spent fuel. Four foot thick windows placed in the wall allow the technicians to visually control the manipulators. These windows would be exposed to the heat of the metal fire. This analysis determines if the thermal stress caused by the fire would crack the windows and if the heat would degrade the window seals allowing radioactivity to escape from the cell.
, Noura Ali Alomayrah
World Journal of Nuclear Science and Technology, Volume 06, pp 15-22; https://doi.org/10.4236/wjnst.2016.61002

Abstract:
Compact toroidal magnetized plasmas are an important part of the world’s magnetic fusion and plasma science efforts. These devices can play an integral role in the development of magnetic fusion as a viable commercial energy source, and in our understanding of plasma instabilities, particle and energy transport, and magnetic field transport. In this paper, we are developing a numerical program to study the magnetic dynamo or relaxation of CT’s characterized by arbitrary tight aspect ratio (major to minor radii of tokamak) and arbitrary cross-sections (Multi-pinch and D-Shaped). The lowest ZFE’s has been calculated through the Taylor’s relaxed state (force-free) toroidal plasmas equation. For ZFE’s, we use the toroidal flux vanishing boundary condition along the whole boundary of tokamaks. Several runs of the program for various wave numbers showed that ZFE was very insensitive to the choice of wave numbers. Besides, the CT’s poloidal magnetic field topologies are well represented. It was very interesting to check our methods for the cases when aspect ratio tends to unity (zero tokamak whole). A good fulfillment of the boundary condition is achieved.
, Jorge Marin, Mario Barrera,
World Journal of Nuclear Science and Technology, Volume 05, pp 274-286; https://doi.org/10.4236/wjnst.2015.54027

Abstract:
Engineering of nuclear fuels using monolithic plates of uranium-molybdenum and Al-6061 cladding is the current challenge for research and test reactors. The main drawback of the manufacture of monolithic nuclear fuel was analyzed using two surface coating methods: aluminum sputtering and transient liquid phase bonding (TLPB). Coating was done with a commercial alloy of Al-Si (R-4047). These techniques were used to improve the metallurgical bonding between the UMo and the cladding by rolling. Finally, design parameters and manufacture of UMo plate fuels were established. Mechanical tests were used to characterize the plates, resulting in UTS values of about 700 and 1000 MPa for the UMo alloys. These results are complemented with metrological analyses, X-Ray diffraction (XRD), thermal analyses, and metallography. X-rays and ultrasound scanners were used to monitor bonding and the co-rolling effects. These initial results show the main obstacles to the engineering development of UMo monolithic plate fuels with Al-6061 cladding, and these are discussed herein.
, Jinsen Xie, Lihua He
World Journal of Nuclear Science and Technology, Volume 05, pp 253-264; https://doi.org/10.4236/wjnst.2015.54025

Abstract:
The purpose of the study is to analyze the breeding ratio of a supercritical water cooled fast reactor (SCFR) and to increase the breeding core of SCFR. The sensitivities of assembly parameters, core arrangements and fuel nuclide components to the breeding ratio are analyzed. In assembly parameters, the seed fuel rod diameter has higher sensitivities to the conversion ratio (CR) than the coolant tube diameter in blanket. Increasing heavy metal fraction is good to CR improvement. The CR of SCFR also increases with a reasonable core arrangement and Pu isotope mass fraction reduction in fuel, which can achieve more negative coolant void reactivity coefficient at the same time. The breeding ratio of SCFR is 1.03128 with a new core arrangement. And the coolant void reactivity coefficient is negative, which achieves a fuel breeding in initial fuel cycle.
Page of 5
Articles per Page
by
Show export options
  Select all
Back to Top Top