• Nuclear Engineering and Technology
• /
• v.53 no.7
• /
• pp.2126-2132
• /
• 2021

Various research groups and private interprises are pursuing the design of a Molten Salt Reactor (MSR) as one of the Generation-IV concepts. In the current work a fast neutron MSR using chloride fuel is analyzed, specially analyzing the power production and neutron flux level in the Intermediate Heat Exchanger (IHX). The neutronic analysis in this work is based on a chloride-fuel MSR with 600 MW thermal power. The core power density was set to 100 MW m-3 with a core H/D [[EQUATION]] 1.0 amd four Intermediate Heat Exchanger (IHX). This leads to a power of 150 MW per IHX; this power is also comparable to the IHX proposed in the SAMOFAR framework. In this work, a preliminary design of a 150 MW helical-coil IHX for a chloride-fueled MSR is prepared and the fission rate, capture rate, and inelastic scatter rate are evaluated.

• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.12 no.1
• /
• pp.85-92
• /
• 2016

The operating temperature of VHTR components is much higher than that of conventional PWR due to high core outlet temperature of VHTR. Material requirements and technical issues of VHTR reactor components which are mainly dominated by high temperature service condition were discussed. The codification effort for high temperature material and design methodology are explained. The design class for VHTR components are classified as class A or B according to the recent ASME high temperature reactor design code. A separation of thermal boundary and pressure boundary is used for VHTR components as an elevated design solution. Key design characteristics for reactor pressure vessel, control rod, reactor internals, graphite reflector, circulator and intermediate heat exchanger were analysed. Thermo-mechanical analysis of the process heat exchanger, which was manufactured for test, is presented as an analysis example.

• Journal of computational fluids engineering
• /
• v.21 no.1
• /
• pp.19-29
• /
• 2016

A Prototype Gen-IV Sodium-cooled Fast Reactor which is one of the $4^{th}$ generation nuclear reactors is in development by Korea Atomic Energy Research Institute. The reactor is composed of four main fluid systems which are categorized by its functions, i.e., Primary Heat Transport System, Intermediate Heat Transport System, Decay Heat Removal System and Sodium-Water Reaction Pressure Relief System. The coolant of the reactor is liquid sodium and sodium-to-sodium heat exchangers are installed at the interfaces between two fluid systems, Intermediate Heat Exchangers between the Primary Heat Transport System and the Intermediate Heat Transport System and Decay Heat Exchangers between the Primary Heat Transport System and the Decay Heat Removal System. For the design and performance analysis of the Intermediate Heat Exchanger and the Decay Heat Exchanger, a computer code was written during previous step of research. In this work, the computer code named "SHXSA" has been validated preliminarily by computational fluid dynamics simulations.

• Journal of the Korean Ceramic Society
• /
• v.48 no.1
• /
• pp.52-56
• /
• 2011

Silicon carbide (SiC) is a candidate material for heat exchangers for VHTR (Very High Temperature Gas Cooled Reactor) due to its refractory nature and high thermal conductivity. This research has focused on demonstration of physical properties and mock-up fabrication for the future heat exchange applications. It was found that the SiC-based components can be applied for process heat exchanger (PHE) and intermediate heat exchanger (IHX), which are operated at $400{\sim}1000^{\circ}C$, based on our examination for the following aspects: optimum fabrication technologies (design, machining and bonding) for compact design, thermal conductivity, corrosion resistance in sulfuric acid environment at high temperature, and simulation results on heat transferring and thermal stress distribution of heat exchanger mock-up.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.34 no.12
• /
• pp.1093-1099
• /
• 2010

For Very High Temperature Reactors (VHTR), the designs of the Intermediate Heat Transport Loop (IHTL) and the Intermediate Heat Exchanger (IHX) are particularly difficult because of the high-temperature operation (up to $950^{\circ}C$). In this study, Flinak molten salt, a eutectic mixture of LiF, NaF, and KF (46.5:11.5:42.0 mole %) is considered as the heat transporting fluid in the IHTL. To evaluate the flow and heat transfer performance of the Flinak molten salt in small channels with hydraulic diameters in the millimeter range, a double-pipe heat exchanger was constructed using small-diameter tubes for the heat exchange between the Flinak and the gas flow. The experimental data showed that, for laminar Flinak flow, the measured friction factors were close to the 64/Re curve and the Nusselt numbers were generally between 3.66 and 4.36.

• Nuclear Engineering and Technology
• /
• v.48 no.6
• /
• pp.1349-1359
• /
• 2016

Alternative control schemes for an Advanced High Temperature Reactor system consisting of a reactor, an intermediate heat exchanger, and a secondary heat exchanger (SHX) are presented in this paper. One scheme is designed to control the cold outlet temperature of the SHX ($T_{co}$) and the hot outlet temperature of the intermediate heat exchanger ($T_{ho2}$) by manipulating the hot-side flow rates of the heat exchangers ($F_h/F_{h2}$) responding to the flow rate and temperature disturbances. The flow rate disturbances typically require a larger manipulation of the flow rates than temperature disturbances. An alternate strategy examines the control of the cold outlet temperature of the SHX ($T_{co}$) only, since this temperature provides the driving force for energy production in the power conversion unit or the process application. The control can be achieved by three options: (1) flow rate manipulation; (2) reactor power manipulation; or (3) a combination of the two. The first option has a quicker response but requires a large flow rate change. The second option is the slowest but does not involve any change in the flow rates of streams. The third option appears preferable as it has an intermediate response time and requires only a minimal flow rate change.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.5
• /
• pp.665-671
• /
• 2013

In a Korean Generation IV prototype sodium-cooled fast reactor (SFR), various types of high-temperature heat exchangers such as IHX (intermediate heat exchanger), DHX (decay heat exchanger), AHX (air heat exchanger), FHX (finned-tube sodium-to-air heat exchanger), and SG (steam generator) are to be designed and installed. In this study, the high-temperature design and integrity evaluation of the sodium-to-air heat exchanger AHX in the STELLA-1 (sodium integral effect test loop for safety simulation and assessment) test loop already installed at KAERI (Korea Atomic Energy Research Institute) and FHX in the SEFLA (sodium thermal-hydraulic experiment loop for finned-tube sodium-to-air heat exchanger) test loop to be installed at KAERI have been performed. Evaluations of creep-fatigue damage based on full 3D finite element analyses were conducted for the two heat exchangers according to the high-temperature design codes, and the integrity of the high-temperature design of the two heat exchangers was confirmed.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
• /
• v.11 no.2
• /
• pp.1-6
• /
• 2015

The horizontal earth-to-air heat exchanger (HEAHES) thermal performance is excellent on cooling and heating season in hot arid regions was reported. But the HEAHES thermal performance results is difficult to find on intermediate season. This paper was performed full scaled experiment to investigate HEAHES thermal performance on intermediate season (Oct. 10th ~ 12th Nov. 12th). When the air entering to HEAHES is the lowest $2.3^{\circ}C$, outlet air temperature from HEAHES is $15.95^{\circ}C$ through PVC pipe that buried length 60m and depth 3m. When the air entering to HEAHES is the highest $24.8^{\circ}C$, outlet air temperature from HEAHES is $22.05^{\circ}C$. During intermediate season, the HEAHES COP is 2.71 in daytime and 6.53 in evening.

• Korean Chemical Engineering Research
• /
• v.52 no.4
• /
• pp.459-466
• /
• 2014

SI Cyclic process is one of the thermochemical hydrogen production processes using iodine and sulfur for producing hydrogen molecules from water. VHTR (Very High Temperature Reactor) can be used to supply heat to hydrogen production process, which is a high temperature nuclear reactor. IHX (Intermediate Heat Exchanger) is necessary to transfer heat to hydrogen production process safely without radioactivity. In this study, the strategy for the optimum design of IHX between SI hydrogen process and VHTR is proposed for various operating pressures of the reactor, and the different cooling fluids. Most economical efficiency of IHX is also proposed along with process conditions.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.9
• /
• pp.1189-1194
• /
• 2013

The Intermediate Heat Exchanger (IHX) of a Very High Temperature Reactor (VHTR) is a core component that transfers the high heat of $950^{\circ}C$ generated in the VHTR to a hydrogen production plant. The Korea Atomic Energy Research Institute manufactured a lab-scale prototype of a Printed Circuit Heat Exchanger (PCHE) as a candidate for an IHX. In this study, as a part of a high-temperature structural integrity evaluation of the lab-scale PCHE prototype made of SUS316L, we carried out high temperature structural analysis modeling and macroscopic thermal and elastic structural analysis for the lab-scale PCHE prototype under helium experimental loop (HELP) test conditions as a precedent study prior to the performance test in HELP.