The Experts below are selected from a list of 66555 Experts worldwide ranked by ideXlab platform
Mamoru Ishii - One of the best experts on this subject based on the ideXlab platform.
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simulation and uncertainty analysis of main steam line break accident on an Integral Test facility
Annals of Nuclear Energy, 2020Co-Authors: Ye Yang, Chengcheng Deng, Jun Yang, Mamoru IshiiAbstract:Abstract In order to investigate the performance of a Generation III BWR safety system, an Integral Test facility was designed and conducted, and several Integral Tests were performed. The best estimate safety analysis of Main Steam Line Break (MSLB) accident using RELAP5/MOD3.3 and RELAP/SCDAPSIM/MOD3.4 (from now on referred as RELAP/SCDAP3.4) was performed. By comparing the simulation results with the Test results, the prediction capability of the RELAP5/MOD3.3 and the RELAP/SCDAP3.4 was compared and analyzed. The RELAP/SCDAP3.4 code was selected to perform the uncertainty study. According to the Phenomenon Identification and Ranking Table, 12 input treatable parameters and 29 source code coefficients were selected with imposed uncertainty distribution to conduct uncertainty analysis. The 95/95 uncertainty band of the minimum core collapsed level were obtained and analyzed. In addition, the contribution weight of input treatable parameters and source code coefficients for the minimum core collapsed level were identified with the Spearman rank correlation coefficient.
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esbwr passive safety system performance under loss of coolant accidents
Progress in Nuclear Energy, 2017Co-Authors: Somboon Rassame, Takashi Hibiki, Mamoru IshiiAbstract:Abstract Several passive safety systems are included in the design of the Economic Simplified Boiling Water Reactor (ESBWR) safety system. To investigate the capability of the ESBWR passive safety system, the Integral facility designed for ESBWR was applied to perform a series of experiments simulating Loss of Coolant Accidents (LOCAs) break events of the ESBWR. This paper is intended to summarize the LOCAs Test results performed at the Purdue University Multi-Dimensional Integral Test Assembly for ESBWR application (PUMA-E) facility, namely, the Main Steam Line Break (MSLB), Bottom Drain Line Break (BDLB), Feed Water Line Break (FWLB) and Gravity Drain Line Break (GDLB). Furthermore, this study focuses on the comparison of important parameters in the main components such as Reactor Pressure Vessel (RPV), Containment, and Suppression Pool (SP) of the Integral facility for those types of the LOCAs Tests in three different phases of LOCAs, namely, the blowdown phase, Gravity Driven Coolant System (GDCS) period and long term cooling PCCS period. The various responses of passive safety function by GDCS, Isolation Coolant System (ICS), and Passive Containment Coolant System (PCCS) at the three different phases of LOCAs to the four types of the LOCAs Tests are discussed and analyzed.
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experimental investigation of void distribution in suppression pool over the duration of a loss of coolant accident using steam water two phase mixture
Annals of Nuclear Energy, 2015Co-Authors: Somboon Rassame, Matthew Griffiths, Jun Yang, Takashi Hibiki, Subash Sharma, Mamoru IshiiAbstract:Abstract Studies are underway to determine if a large amount gas discharged through the downcomer pipes in the pressure suppression chamber during the blowdown of Loss of Coolant Accident (LOCA) can potentially be entrained into the Emergency Core Cooling System (ECCS) suction piping of BWR. This may result in degraded ECCS pumps performance which could affect the ability to maintain or recover the water inventory level in the Reactor Pressure Vessel (RPV) during a LOCA. Therefore, it is very important to understand the void behavior in the pressure suppression chamber during the blowdown period of a LOCA. To address this issue, a set of experiments is conducted using the Purdue University Multi-Dimensional Integral Test Assembly for ESBWR applications (PUMA-E) facility. The geometry of the Test apparatus is determined based on the basic geometrical scaling analysis from a prototypical BWR containment (MARK I) with a consideration of downcomer size, downcomer water submergence depth and Suppression Pool (SP) water level. Several instruments are installed in the Test facility to measure the required experimental data such as the steam mass flow rate, void fraction, pressure and temperature. In the experiments, sequential flows of air, steam–air mixture and pure steam-each with the various flow rate conditions are injected from the Drywell (DW) through a downcomer pipe in the SP. Eight Tests with two different downcomer sizes, various initial gas volumetric fluxes at the downcomer, and two different initial non-condensable gas concentration conditions in the DW are conducted. Three distinct phases, namely, an initial phase, a quasi-steady, and a chugging phase are observed. The maximum void penetration depth is observed in the initial phase. A reduction in the void penetration depth is observed in the quasi-steady phase. As a result of low non-condensable gas concentration, chugging is observed at the tail end of the experiment. Chugging provides renewed void penetrations comparable to those in the initial phase. It is determined that the void distribution and area of void penetration in the SP is governed by the gas volumetric flux at the downcomer and the non-condensable gas concentration in the downcomer.
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experimental investigation of void distribution in suppression pool during the initial blowdown period of a loss of coolant accident using air water two phase mixture
Annals of Nuclear Energy, 2014Co-Authors: Somboon Rassame, Matthew Griffiths, Jun Yang, Doo Yong Lee, Sung Won Choi, Takashi Hibiki, Mamoru IshiiAbstract:Abstract During the initial blowdown period of a Loss of Coolant Accident (LOCA), the non-condensable gas initially contained in the BWR containment is discharged to the pressure suppression chamber through the blowdown pipes. The performance of Emergency Core Cooling System (ECCS) can be degraded due to the released gas ingestion into the suction intakes of the ECCS pumps. The understanding of the relevant phenomena in the pressure suppression chamber is important in analyzing potential gas intrusion into the suction intakes of ECCS pumps. To obtain the basic understanding of the relevant phenomena and the generic data of void distribution in the pressure suppression chamber during the initial blowdown period of a LOCA, Tests with various blowdown conditions were conducted using the existing Suppression Pool (SP) tank of the Integral Test facility, called Purdue University Multi-Dimensional Integral Test Assembly for ESBWR applications (PUMA-E) facility, a scaled downcomer pipe installed in the PUMA-E SP, and air discharge pipe system. Two different diameter sizes of air injection pipe (0.076 and 0.102 m), a range of air volumetric flux (7.9–24.7 m/s), initial void conditions in an air injection pipe (fully void, partially void, and fully filled with water) and different air velocity ramp rates (1.0, 1.5, and 2.0 s) are used to investigate the impact of the blowdown conditions to the void distribution in the SP. Two distinct phases of experiments, namely, an initial and a quasi-steady phase were observed. The maximum void penetration depth was experienced during the initial phase. The quasi-steady phase provided less void penetration depth and was categorized by oscillations in the void penetration. The initial void conditions in an air injection pipe and air volumetric fluxes were only found to significantly impact on the void distribution in the SP.
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Startup transient simulation for natural circulation boiling water reactors in PUMA facility
Nuclear Engineering and Design, 2006Co-Authors: Selim Kuran, Ho Jun Yoon, Y. Xu, Ling Cheng, Shripad T. Revankar, Mamoru Ishii, W WangAbstract:In view of the importance of instabilities that may occur at low-pressure and -flow conditions during the startup of natural circulation boiling water reactors, startup simulation experiments were performed in the Purdue University Multi-Dimensional Integral Test Assembly (PUMA) facility. The simulations used pressure scaling and followed the startup procedure of a typical natural circulation boiling water reactor. Two simulation experiments were performed for the reactor dome pressures ranging from 55 kPa to 1 MPa, where the instabilities may occur. The experimental results show the signature of condensation-induced oscillations during the single-phase-to-two-phase natural circulation transition. The results also suggest that a rational startup procedure is needed to overcome the startup instabilities in natural circulation boiling water reactor designs.
Qinglian Wang - One of the best experts on this subject based on the ideXlab platform.
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isobaric vapor liquid equilibrium of the binary system sec butyl acetate para xylene and the quaternary system methyl acetate para xylene sec butyl acetate acetic acid at 101 3 kpa
Fluid Phase Equilibria, 2015Co-Authors: Dan Huang, Chen Yang, Qinglian WangAbstract:Abstract Isobaric vapor–liquid equilibrium (VLE) of sec-butyl acetate + para-xylene binary system and methyl acetate + para-xylene + sec-butyl acetate + acetic acid quaternary system were determined at 101.3 kPa in a modified Rose still, so as to provide a basis for the design and simulation of the separation process of acetic acid dehydration system. In the present study, the L–W Integral Test was used to check the thermodynamic consistency of binary VLE data. The results indicated that the thermodynamic consistency of binary VLE data measured in this paper was satisfactory. Furthermore, binary experimental data were correlated well by three models, which are the NRTL, Wilson and UNIQUAC models, respectively. Subsequently, the corresponding binary interaction parameters of each model were obtained. In addition, the NRTL activity coefficient model in combination with Marek–Standart chemical theory was used to predict the quaternary system VLE data for the association of acetic acid.
Dan Huang - One of the best experts on this subject based on the ideXlab platform.
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isobaric vapor liquid equilibrium of the binary system sec butyl acetate para xylene and the quaternary system methyl acetate para xylene sec butyl acetate acetic acid at 101 3 kpa
Fluid Phase Equilibria, 2015Co-Authors: Dan Huang, Chen Yang, Qinglian WangAbstract:Abstract Isobaric vapor–liquid equilibrium (VLE) of sec-butyl acetate + para-xylene binary system and methyl acetate + para-xylene + sec-butyl acetate + acetic acid quaternary system were determined at 101.3 kPa in a modified Rose still, so as to provide a basis for the design and simulation of the separation process of acetic acid dehydration system. In the present study, the L–W Integral Test was used to check the thermodynamic consistency of binary VLE data. The results indicated that the thermodynamic consistency of binary VLE data measured in this paper was satisfactory. Furthermore, binary experimental data were correlated well by three models, which are the NRTL, Wilson and UNIQUAC models, respectively. Subsequently, the corresponding binary interaction parameters of each model were obtained. In addition, the NRTL activity coefficient model in combination with Marek–Standart chemical theory was used to predict the quaternary system VLE data for the association of acetic acid.
Hyunsik Park - One of the best experts on this subject based on the ideXlab platform.
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contribution of thermal hydraulic validation Tests to the standard design approval of smart
Nuclear Engineering and Technology, 2017Co-Authors: Hyunsik Park, Sangki Moon, Taesoon Kwon, Sungjae YiAbstract:Abstract Many thermal–hydraulic Tests have been conducted at the Korea Atomic Energy Research Institute for verification of the SMART (System-integrated Modular Advanced ReacTor) design, the standard design approval of which was issued by the Korean regulatory body. In this paper, the contributions of these Tests to the standard design approval of SMART are discussed. First, an Integral effect Test facility named VISTA-ITL (Experimental Verification by Integral Simulation of Transients and Accidents-Integral Test Loop) has been utilized to assess the TASS/SMR-S (Transient and Set-point Simulation/Small and Medium) safety analysis code and confirm its conservatism, to support standard design approval, and to construct a database for the SMART design optimization. In addition, many separate effect Tests have been performed. The reactor internal flow Test has been conducted using the SCOP (SMART COre flow distribution and Pressure drop Test) facility to evaluate the reactor internal flow and pressure distributions. An ECC (Emergency Core Coolant) performance Test has been carried out using the SWAT (SMART ECC Water Asymmetric Two-phase choking Test) facility to evaluate the safety injection performance and to validate the thermal–hydraulic model used in the safety analysis code. The Freon CHF (Critical Heat Flux) Test has been performed using the FTHEL (Freon Thermal Hydraulic Experimental Loop) facility to construct a database from the 5 × 5 rod bundle Freon CHF Tests and to evaluate the DNBR (Departure from Nucleate Boiling Ratio) model in the safety analysis and core design codes. These Test results were used for standard design approval of SMART to verify its design bases, design tools, and analysis methodology.
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comparison of three small break loss of coolant accident Tests with different break locations using the system integrated modular advanced reactor Integral Test loop facility to estimate the safety of the smart design
Nuclear Engineering and Technology, 2017Co-Authors: Hwang Bae, Sung Uk Ryu, Dong Eok Kim, Hyunsik ParkAbstract:Abstract Three small-break loss-of-coolant accident (SBLOCA) Tests with safety injection pumps were carried out using the Integral-effect Test loop for SMART (System-integrated Modular Advanced ReacTor), i.e., the SMART-ITL facility. The types of break are a safety injection system line break, shutdown cooling system line break, and pressurizer safety valve line break. The thermal–hydraulic phenomena show a traditional behavior to decrease the temperature and pressure whereas the local phenomena are slightly different during the early stage of the transient after a break simulation. A safety injection using a high-pressure pump effectively cools down and recovers the inventory of a reactor coolant system. The global trends show reproducible results for an SBLOCA scenario with three different break locations. It was confirmed that the safety injection system is robustly safe enough to protect from a core uncovery.
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an experimental investigation of core makeup tank behavior using smart itl during small break loss of coolant accident
대한기계학회 춘추학술대회, 2015Co-Authors: Hyobong Ryu, Sung Uk Ryu, Hwang Bae, Byongguk Jeon, Sunjoon Byun, Hyunsik ParkAbstract:An Integral type reactor, SMART (System-integrated Modular Advanced ReacTor) has been recently equipped with an additional passive safety system, which maintains the reactor in a safe condition during the design basis accident without any AC power to drive the safety injection pumps and operator action. For verification of the SMART passive safety system, a single train of a passive safety system consisting of a core makeup tank (CMT), a safety injection tank (SIT), and two stages of an automatic depressurization system (ADS) were additionally attached to the existing SMART-ITL (Integral Test Loop for SMART) facility. In this paper, we describe the Test procedure and Test result of a SBLOCA simulation to evaluate the performance of the CMT, which has a flow distributor in the upper part. The Test was carried out according to the sequence of events (SOE) for an SBLOCA scenario. Most of the thermal-hydraulic properties of the CMT, such as the pressure, temperature, injection flow rate, and water level were obtained during the Test with the operation of the passive safety system. We conducted experiments using two types of CMT, which have the same volume but different aspect ratio, called CMT #1-1 and CMT #1-2 for a better understanding of the shape effect. Characteristic properties such as the pressure, thermal stratification, and injection behavior were studied and compared.
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an experimental investigation on thermal hydraulic interaction between core makeup tank and safety injection tank of an Integral small reactor during a small break loss of coolant accident
ASME JSME KSME 2015 Joint Fluids Engineering Conference, 2015Co-Authors: Hwang Bae, Hyobong Ryu, Sung Uk Ryu, Woo Shik Kim, Hyunsik ParkAbstract:A passive injection Test was conducted using a core makeup tank (CMT), a safety injection tank (SIT) and an automatic depressurization system (ADS), which consists of a passive safety system (PSS) of the SMART reactor. This paper investigates the thermal-hydraulic interaction between CMT and SIT during sequential injections of coolant from these two tanks to a high-temperature and high-pressure reactor pressure vessel using an Integral effect Test facility of SMART-ITL (System-Integrated Modular Advanced ReacTor-Integral Test Loop). Both CMT and SIT were connected to the reactor pressure vessel by a pressure balance line (PBL) and injection line (IL). A steady-state condition was maintained for 1,000 seconds before the start of the injection. The major parameters agreed well with the target value. After one of safety injection system line was simulated to be broken, a transient injection Test was conducted according to the small-break loss-of-coolant accident (SBLOCA) scenario. Coolant injections from a CMT and SIT were started sequentially by opening quick-opening valves installed on the IL and PBL piping, respectively. Several thermal-hydraulic phenomena such as direct contact condensation, thermal stratification, and coupling effects between the CMT and SIT were locally observed during the SBLOCA scenario. The results show that the adopted passive safety injection system functions well as an emergency core cooling system.Copyright © 2015 by KSME
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parametric studies on thermal hydraulic characteristics for transient operations of an Integral type reactor
Nuclear Engineering and Technology, 2006Co-Authors: Kiyong Choi, Hyunsik Park, Seok Cho, Choon Kyung Park, Chul Hwa Song, Moon Ki ChungAbstract:Transient operations for an Integral type reactor, SMART-P, have been experimentally investigated using a thermal-hydraulic Integral Test facility, VISTA (Experimental Verification by Integral Simulation of Transients and Accidents), in order to verify the system design and performance of the SMART-P, a pilot plant of SMART. The VISTA facility was subjected to various accident conditions such as feedwater increase and decrease, loss of coolant flow, and control rod withdrawal accidents in order to elucidate the thermal-hydraulic responses following such accidents and finally to verify the system design of the SMARTP. Full functional control logics have been implemented in the VISTA facility in order to control the required control action for an accident simulation. As one of the sensitivity Tests to verify the PRHRS performance, the effects of the initial water level in the compensation tank are experimentally investigated. When the initial water level is 16%, the water is quickly drained and nitrogen gas is then introduced into the PRHR system, resulting in deterioration of the PRHRS performance. It is thus found that nitrogen ingression should be prevented to ensure stable PRHRS operation.
Chen Yang - One of the best experts on this subject based on the ideXlab platform.
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isobaric vapor liquid equilibrium of the binary system sec butyl acetate para xylene and the quaternary system methyl acetate para xylene sec butyl acetate acetic acid at 101 3 kpa
Fluid Phase Equilibria, 2015Co-Authors: Dan Huang, Chen Yang, Qinglian WangAbstract:Abstract Isobaric vapor–liquid equilibrium (VLE) of sec-butyl acetate + para-xylene binary system and methyl acetate + para-xylene + sec-butyl acetate + acetic acid quaternary system were determined at 101.3 kPa in a modified Rose still, so as to provide a basis for the design and simulation of the separation process of acetic acid dehydration system. In the present study, the L–W Integral Test was used to check the thermodynamic consistency of binary VLE data. The results indicated that the thermodynamic consistency of binary VLE data measured in this paper was satisfactory. Furthermore, binary experimental data were correlated well by three models, which are the NRTL, Wilson and UNIQUAC models, respectively. Subsequently, the corresponding binary interaction parameters of each model were obtained. In addition, the NRTL activity coefficient model in combination with Marek–Standart chemical theory was used to predict the quaternary system VLE data for the association of acetic acid.