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- 저자 : KAMAL HADAD (검색결과 5 건)
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Hassan Saadati,KAMAL HADAD,Ataollah Rabiee 한국원자력학회 2018 Nuclear Engineering and Technology Vol.50 No.5
In this study, the effects of selecting water/silver nanofluid as both a coolant and a reactivity controllerduring the first operating cycle of a light water nuclear reactor are investigated. To achieve this, coupledneutronicethermo-hydraulic analysis is employed to simulate the reactor core. A detailed VVER1000/446reactor core is modeled in monte carlo code (MCNP), and the model is verified using the porous mediaapproach. Results show that the maximum required level of silver nanoparticles is 1.3 Vol.% at thebeginning of the cycle; this value drops to zero at the end of cycle. Due to substitution of water/boric acidwith water/Ag nanofluid, reactor operation time at maximum power extends to 357.3 days, and theenergy generation increases by about 27.3%. The higher negative coolant temperature coefficient ofreactivity in the presence of nanofluid in comparison with the water/boric acid indicates that the reactoris inherently safer. Considering the safety margins in the presence of the nanofluid, minimum departurefrom nucleate boiling ratio is calculated to be 2.16 (recommendation is 1.75).
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AHMAD PIROUZMAND,KAMAL HADAD,서균렬 한국원자력학회 2011 Nuclear Engineering and Technology Vol.43 No.3
This paper considers the concept of analog computing based on a cellular neural network (CNN) paradigm to simulate nuclear reactor dynamics using a time-dependent second order form of the neutron transport equation. Instead of solving nuclear reactor dynamic equations numerically, which is time-consuming and suffers from such weaknesses as vulnerability to transient phenomena, accumulation of round-off errors and floating-point overflows, use is made of a new method based on a cellular neural network. The state-of-the-art shows the CNN as being an alternative solution to the conventional numerical computation method. Indeed CNN is an analog computing paradigm that performs ultra-fast calculations and provides accurate results. In this study use is made of the CNN model to simulate the space-time response of scalar flux distribution in steady state and transient conditions. The CNN model also is used to simulate step perturbation in the core. The accuracy and capability of the CNN model are examined in 2D Cartesian geometry for two fixed source problems, a mini-BWR assembly, and a TWIGL Seed/Blanket problem. We also use the CNN model concurrently for a typical small PWR assembly to simulate the effect of temperature feedback, poisons, and control rods on the scalar flux distribution.
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Pirouzmand, Ahmad,Hadad, Kamal,Suh, Kune Y. Korean Nuclear Society 2011 Nuclear Engineering and Technology Vol.43 No.3
This paper considers the concept of analog computing based on a cellular neural network (CNN) paradigm to simulate nuclear reactor dynamics using a time-dependent second order form of the neutron transport equation. Instead of solving nuclear reactor dynamic equations numerically, which is time-consuming and suffers from such weaknesses as vulnerability to transient phenomena, accumulation of round-off errors and floating-point overflows, use is made of a new method based on a cellular neural network. The state-of-the-art shows the CNN as being an alternative solution to the conventional numerical computation method. Indeed CNN is an analog computing paradigm that performs ultra-fast calculations and provides accurate results. In this study use is made of the CNN model to simulate the space-time response of scalar flux distribution in steady state and transient conditions. The CNN model also is used to simulate step perturbation in the core. The accuracy and capability of the CNN model are examined in 2D Cartesian geometry for two fixed source problems, a mini-BWR assembly, and a TWIGL Seed/Blanket problem. We also use the CNN model concurrently for a typical small PWR assembly to simulate the effect of temperature feedback, poisons, and control rods on the scalar flux distribution.
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Rahimi, Ghasem,Nematollahi, MohammadReza,Hadad, Kamal,Rabiee, Ataollah Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.3
Research reactors for radioisotope production, fuel and material testing and research activities are designed, constructed and operated based on the society's needs. In this study, neutronic and thermal hydraulic design of a high neutron flux research reactor core for radioisotope production is presented. Main parameters including core excess reactivity, reactivity variations, power and flux distribution during the cycle, axial and radial power peaking factors (PPF), Pu<sub>239</sub> production and minimum DNBR are calculated by nuclear deterministic codes. Core calculations performed by deterministic codes are validated with Monte Carlo code. Comparison of the neutronic parameters obtained from deterministic and Monte Carlo codes indicates good agreement. Finally, subchannel analysis performed for the hot channel to evaluate the maximum fuel and clad temperatures. The results show that the average thermal neutron flux at the beginning of cycle (BOC) is 1.0811 × 10<sup>14</sup> n/㎠-s and at the end of cycle (EOC) is 1.229 × 10<sup>14</sup> n/㎠-s. Total Plutonium (Pu<sub>239</sub>) production at the EOC evaluated to be 0.9487 Kg with 83.64% grade when LEU (UO<sub>2</sub> with 3.7% enrichment) used as fuel. This designed reactor which uses LEU fuel and has high neutron flux and low plutonium production could be used for peaceful nuclear activities based on nuclear non-proliferation treaty concepts.
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Two-Phase Flow Field Simulation of Horizontal Steam Generators
Ataollah Rabiee,Amir Hossein Kamalinia,KAMAL HADAD 한국원자력학회 2017 Nuclear Engineering and Technology Vol.49 No.1
The analysis of steam generators as an interface between primary and secondary circuitsin light water nuclear power plants is crucial in terms of safety and design issues. VVER-1000 nuclear power plants use horizontal steam generators which demand a detailedthermal hydraulics investigation in order to predict their behavior during normal andtransient operational conditions. Two phase flow field simulation on adjacent tube bundlesis important in obtaining logical numerical results. However, the complexity of the tubebundles, due to geometry and arrangement, makes it complicated. Employment of porousmedia is suggested to simplify numerical modeling. This study presents the use of porousmedia to simulate the tube bundles within a general-purpose computational fluid dynamicscode. Solved governing equations are generalized phase continuity, momentum,and energy equations. Boundary conditions, as one of the main challenges in thisnumerical analysis, are optimized. The model has been verified and tuned by simpletwo-dimensional geometry. It is shown that the obtained vapor volume fraction near thecold and hot collectors predict the experimental results more accurately than in previousstudies.
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