Tài liệu miễn phí Năng lượng
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Mathematical approach for optimization of magnetohydrodynamic circulation system
The geometrical and electromagnetic variables of a rectangular-type magnetohydrodynamic (MHD) circulation system are optimized to solve MHD equations for the active decay heat removal system of a prototype Gen-IV sodium fast reactor. Decay heat must be actively removed from the reactor coolant to prevent the reactor system from exceeding its temperature limit. A rectangular-type MHD circulation system is adopted to remove this heat via an active system that produces developed pressure through the Lorentz force of the circulating sodium.
7/3/2019 4:39:39 PM +00:00
Radiation protective qualities of some selected lead and bismuth salts in the wide gamma energy region
The radiation protection efficiencies, mean free paths, effective atomic numbers and electron densities for the present compounds were determined. The bismuth fluoride (BiF3) is found to have maximum radiation protection efficiency among the selected salts. The results showed that present salts are more effective for reducing the intensity of gamma photons at low energy region.
7/3/2019 4:39:19 PM +00:00
A new approach to determine batch size for the batch method in the Monte Carlo Eigenvalue calculation
It is well known that the variance of tally is biased in a Monte Carlo calculation based on the power iteration method. Several studies have been conducted to estimate the real variance. Among them, the batch method, which was proposed by Gelbard and Prael, has been utilized actively in many Monte Carlo codes because the method is straightforward, and it is easy to implement the method in the codes.
7/3/2019 4:39:03 PM +00:00
Sorption characteristics of iodide on chalcocite and mackinawite under pH variations in alkaline conditions
In addition, when the alkalinity increased higher than a pH of 12, the sorption capacity of both minerals decreased dramatically, likely due to the competition of hydroxy ions with the iodide. This result confirmed that chalcocite was an especially good sorbing media for iodide under alkaline conditions with a pH value of less than 12.
7/3/2019 4:38:45 PM +00:00
Conceptual design of ultra-high performance fiber reinforced concrete nuclear waste container
This research presents a structural design of high-level waste (HLW) container using ultra-high performance fiber reinforced concrete (UHP-FRC) material. The proposed design aims to overcome the drawbacks of the existing concrete containers which are heavy, difficult to fabricate, and expensive. In this study, the dry storage container (DSC) that commonly used at Canadian Nuclear facilities is selected to present the proposed design.
7/3/2019 4:38:21 PM +00:00
Solidification of high level waste using magnesium potassium phosphate compound
Compound samples based on the mineral-like magnesium potassium phosphate matrix MgKPO4 6H2O were synthesized by solidification of high level waste surrogate. Phase composition and structure of synthesized samples were studied by XRD and SEM methods. Compressive strength of the compounds is 12 ± 3 MPa.
7/3/2019 4:38:01 PM +00:00
Comparison of knife-edge and multi-slit camera for proton beam range verification by Monte Carlo simulation
The mechanical-collimation imaging is the most mature technology in prompt gamma (PG) imaging which is considered the most promising technology for beam range verification in proton therapy. The purpose of the present study is to compare the performances of two mechanical-collimation PG cameras, knife-edge (KE) camera and multi-slit (MS) camera.
7/3/2019 4:37:44 PM +00:00
Impact of thermal and chemical treatment on the mechanical properties of E110 and E110G cladding tubes
The mechanical and corrosion behavior of the Russian zirconium fuel cladding alloy E110, predominantly used in VVERs, has been investigated for many decades. The recent commercialization of a new, optimized E110 alloy, produced on a sponge zirconium basis, gave the opportunity to compare the mechanical properties of the old and the new E110 fuel claddings.
7/3/2019 4:37:24 PM +00:00
Influence of design modification of control rod assembly for Prototype Generation IV Sodium-cooled Fast Reactor on drop performance
This paper presents the drop performance test of the control rod assembly which is one of the main components strongly related to the safety of the prototype generation IV sodium-cooled fast reactor. To investigate the drop performance, a real-sized control rod assembly that was recently modified based on the drop analysis results was newly fabricated, and several free drop tests under different flow rate conditions were carried out.
7/3/2019 4:37:05 PM +00:00
RCD success criteria estimation based on allowable coping time
Current probabilistic safety assessment evaluates that core damage can be prevented under small-break LOCA (SBLOCA) and steam generator tube rupture (SGTR) with rapid cool down (RCD) strategy when all safety injection systems are unavailable. However, previous research has pointed out a limitation of RCD in terms of initiation time.
7/3/2019 4:36:45 PM +00:00
Determination of plutonium and uranium content and burnup using six group delayed neutrons
In this study, investigation of spent fuel was performed using six group delayed neutron parameters. Three used fuels (F1, F2, and F11) which are burnt over the years in the core of Missouri University of Science and Technology Reactor (MSTR), were investigated. F16 fresh fuel was used as plutonium free fuel element and compared with irradiated used fuels to develop burnup and Pu discrimination method.
7/3/2019 4:36:29 PM +00:00
Detonation cell size model based on deep neural network for hydrogen, methane and propane mixtures with air and oxygen
The aim of the present study was to develop model for detonation cell sizes prediction based on a deep artificial neural network of hydrogen, methane and propane mixtures with air and oxygen. The discussion about the currently available algorithms compared existing solutions and resulted in a conclusion that there is a need for a new model, free from uncertainty of the effective activation energy and the reaction length definitions.
7/3/2019 4:36:09 PM +00:00
Measurement of safety rods reactivity worth by advanced source jerk method in HWZPR
In this paper, the reactivity worth of safety rods in Heavy Water Zero Power Reactor (HWZPR) in the new lattice pitch is measured by advanced source jerk method. The average of the results related to two different detectors is equal to 29.88 mk.
7/3/2019 4:35:54 PM +00:00
Numerical analysis on the rapid fire suppression using a water mist nozzle in a fire compartment with a door opening
This phenomenon occurred with a displacement of the flame near the liquid fuel pool. Changing the configuration of the door opening with different aspect ratios and opening ratios had impact on the maximum value of the heat release rate due to the flame displacement8305928-main.
7/3/2019 4:35:28 PM +00:00
Fast non-local means noise reduction algorithm with acceleration function for improvement of image quality in gamma camera system: A phantom study
The designed FNLM algorithm is based on local region considerations, including the Euclidean distance in the gamma-ray image and use of the encoded information. To evaluate the noise characteristics, the normalized noise power spectrum (NNPS), contrast-to-noise ratio (CNR), and coefficient of variation (COV) were used. According to the NNPS result, the lowest values can be obtained using the FNLM noise reduction algorithm.
7/3/2019 4:35:09 PM +00:00
Control of accidental discharge of radioactive materials by filtered containment venting system: A review
This paper gives an elaborate description of the different types of FCVS currently being used, the current usage status in over 17 countries and the legislations regarding it. The recent researches being carried out in this field has also been discussed in detail. This present paper focuses on the critical review of existing FCVS, reports the challenges faced by it and highlights the potential developments to overcome the difficulties.
7/3/2019 4:34:43 PM +00:00
A classification of electrical component failures and their human error types in South Korean NPPs during last 10 years
This paper analyzed the root causes of failure and types of human error in 300 cases of electrical component failures. We analyzed the operating experience of electrical components by methods of root causes in K-HPES (Korean-version of Human Performance Enhancement System) and by methods of human error types in HuRAMþ (Human errorRelated event root cause Analysis Method Plus). As a result of analysis, the most electrical component failures appeared as circuit breakers and emergency generators.
7/3/2019 4:34:27 PM +00:00
Numerical investigation on vortex behavior in wire-wrapped fuel assembly for a sodium fast reactor
The wire-wrapped fuel bundle is an assembly design in a sodium-cooled fast reactor. A wire spacer is used to maintain a constant gap between rods and to enhance the mixing of coolants. The wire makes the flow complicated by creating a sweeping flow and vortex flow. The vortex affects the flow field and heat transfer inside the subchannels.
7/3/2019 4:34:03 PM +00:00
DL-RRT* algorithm for least dose path Re-planning in dynamic radioactive environments
This paper presents a sampling-based algorithm, DL-RRT*, for minimum dose walk-path re-planning in radioactive environments, expedient for occupational workers in nuclear facilities to avoid unnecessary radiation exposure. The method combines the principle of random tree star (RRT*) and D* Lite, and uses the expansion strength of grid search strategy from D* Lite to quickly find a high-quality initial path to accelerate convergence rate in RRT*.
7/3/2019 4:33:40 PM +00:00
Room-temperature tensile strength and thermal shock behavior of spark plasma sintered W-K-TiC alloys
The relative density and Vickers micro-hardness of W-K-TiC alloys was enhanced with TiC addition and the highest Vickers micro-hardness is 731.55. As the TiC addition increased from 0.05 to 2 wt%, the room-temperature tensile strength raised from 141 to 353 MPa. The grain size of the W-K-TiC alloys decreased sharply from 2.56 mm to 330 nm with the enhanced TiC doping. The resistance to thermal shock damage of W-K-TiC alloys was improved slightly with the increased TiC addition.
7/3/2019 4:33:19 PM +00:00
Attenuation curves of neutrons from 400 to 550 Mev/u for Ca, Kr, Sn, and U ions in concrete on a graphite target for the design of shielding for the RAON in-flight fragment facility in Korea
The purpose of the present work is to produce and thus increase the amount of shielding data on neutrons generated by high-energy heavy ion beams based on the RAON inflight fragment facility. Calculations were performed with the computational Monte Carlo codes PHITS and MCNPX. The secondary neutron source terms were evaluated at 550 MeV/u for Ca, Kr, and Sn and at 400 MeV/u for U ions on a graphite target. Source terms and attenuation lengths were obtained by fitting the ambient dose equivalent inside an ordinary concrete shield.
7/3/2019 4:32:59 PM +00:00
Determination of reaction kinetics during vitrification of radioactive liquid waste for different types of base glass
In this study, HTO was orally administered to rats at the level of 37 kBq (1 mCi) or 370 kBq (10 mCi) to examine tissue distribution and excretion levels. After sacrifice, wet and dry tissue samples were weighed and analyzed for tissue free-water tritium (TFWT) and organically bound tritium (OBT). The mean tissue concentrations of TFWT (OBT) were 30.9 (17.8) and 4.4 (8.1).
7/3/2019 4:32:41 PM +00:00
Evaluation of dynamic behavior of coagulation-flocculation using hydrous ferric oxide for removal of radioactive nuclides in wastewater
This work studied the dynamic behavior of HFO floc formation during the neutralization of acidic ferric iron in the presence of several radionuclides by using a photometric dispersion analyzer (PDA). Then the coagulation-flocculation system using HFO-anionic poly acrylamide (PAM) composite floc system was evaluated and compared in seawater and distilled water to find the effective condition to remove the target nuclides (Co-60, Mn-54, Sb-125, and Ru-106) present in wastewater generated in the severe accident of nuclear power plant like Fukushima Daiichi case.
7/3/2019 4:32:21 PM +00:00
Rapid and massive throughput analysis of a constant volume high-pressure gas injection system
In this system, the flow is driven by the pressure difference between a gas storage tank and a vacuum vessel with a source pressure. The idea is based on a constant volume system without extra source gases to guarantee rapid response and high throughput. Among them, valves and gas species are studied because their properties could influence the velocity of the fluid field.
7/3/2019 4:32:02 PM +00:00
Numerical evaluation of gamma radiation monitoring
In this study a new AGRS system empowered by ANN-BFGS has been proposed and evaluated on available empirical AGRS data. To that effect different architectures of adaptive ANN-BFGS were implemented for a sort of published experimental AGRS outputs. The selected approach among of various training methods, with its low iteration cost and nondiagonal scaling allocation is a new powerful algorithm for AGRS data due to its inherent stochastic properties.
7/3/2019 4:31:42 PM +00:00
Neutronic study of utilization of discrete thorium-uranium fuel pins in CANDU-6 reactor
The results show that the coolant void reactivity of the assembly analyzed in this paper is lower than that of 37-element bundle cell with natural uranium and 37-element bundle cell with mixed TU fuel pins; that the max time-average channel/bundle power of the core meets the limits - less than 6700kW/860 kW; that the fuel conversion ratio is higher than that of the CANDU-6 reactor with natural uranium; and that the exit burnup increases to 13400 MWd/tU.
7/3/2019 4:31:23 PM +00:00
Effects of collimator on imaging performance of Yttrium-90 Bremsstrahlung photons: Monte Carlo simulation
Various phantoms were employed in the simulation to determine the main energy window using primary-to-scatter ratios (PSRs). Imaging performance was evaluated using spatial resolution indices, imaging counts, scatter fractions, and contrast-to-noise ratios. Collimator choice slightly affected energy spectrum shapes and improved PSRs.
7/3/2019 4:31:03 PM +00:00
Drop formation at submerged nozzles: Comparison of aqueous dispersed and organic dispersed cases for TBP-dodecane and nitric acid system
In this work, the phenomena of aqueous phase and organic phase drop formation at submerged nozzles are compared by conducting experiments with 30%TBP (v/v) in dodecane as the organic phase and nitric acid as the aqueous phase.
7/3/2019 4:30:44 PM +00:00
Three-dimensional numerical simulation of hydrogen-induced multi-field coupling behavior in cracked zircaloy cladding tubes
In the high-temperature and high-pressure irradiation environments, the multi-field coupling processes of hydrogen diffusion, hydride precipitation and mechanical deformation in Zircaloy cladding tubes occur. To simulate this hydrogen-induced complex behavior, a multi-field coupling method is developed, with the irradiation hardening effects and hydride-precipitation-induced expansion and hardening effects involved in the mechanical constitutive relation.
7/3/2019 4:30:25 PM +00:00
An advanced core design for a soluble-boron-free small modular reactor ATOM with centrally-shielded burnable absorber
This research also introduces a supplementary reactivity control mechanism using stainless steel as mechanical shim (MS) rod to obtain the criticality during normal operation. A further analysis is performed to investigate the local power peaking of the CSBA-loaded FA at MS-rodded condition. Moreover, a simple B4C-based control rod arrangement is proposed to assure a sufficient shutdown margin even at the cold-zero-power condition. All calculations in this neutronic-thermal hydraulic coupled investigation of the 3D SBF SMR core are completed by a two-step Monte Carlo-diffusion hybrid methodology.
7/3/2019 4:30:04 PM +00:00