Validation Experiment for the Cooling Capability of Passive Auxiliary Feedwater System (PAFS) With PASCAL Facility

2012 ◽  
Author(s):  
Byoung-Uhn Bae ◽  
Seok Kim ◽  
Yu-Sun Park ◽  
Bok-Deuk Kim ◽  
Kyoung-Ho Kang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Exchanger ◽  
System Analysis ◽  
Thermal Power ◽  
Heat Removal ◽  
Steady State Condition ◽  
Single Tube ◽  
Decay Heat ◽  
Validation Experiment

The Passive Auxiliary Feedwater System (PAFS) is one of the advanced safety features adopted in the APR+ (Advanced Power Reactor Plus) which is intended to completely replace the conventional active auxiliary feedwater system. It removes the decay heat by cooling down the secondary system of the SG using condensation heat exchanger installed in the Passive Condensation Cooling Tank (PCCT). With an aim of validating the cooling and operational performance of the PAFS, PASCAL (PAFS Condensing Heat Removal Assessment Loop), was constructed to experimentally investigate the condensation heat transfer and natural convection phenomena in the PAFS. It simulates a single tube of the passive condensation heat exchangers, a steam-supply line, a return-water line, and a PCCT with a reduced area, which is equivalent to 1/240 of the prototype according to a volumetric scaling methodology with a full height. The objective of the experiment is to investigate the cooling performance and natural circulation characteristics of the PAFS by simulating a steady state condition of the thermal power. From the experiment, two-phase flow phenomena in the horizontal heat exchanger and PCCT were investigated and the cooling capability of the condensation heat exchanger was validated. Test results showed that the design of the condensation heat exchanger in PAFS could satisfy the requirement for heat removal rate of 540 kW per a single tube and the prevention of water hammer phenomenon inside the tube. It also proved that the operation of PAFS played an important role in cooling down the decay heat by natural convection without any active system. The present experimental results will contribute to improve the model of the condensation and boiling heat transfer, and also to provide the benchmark data for validating the calculation performance of a thermal hydraulic system analysis code with respect to the PAFS.

Performance of Sodium Natural Circulation Loop for Passvie Decay Heat Removal

2008 ◽  
Author(s):  
Hae-Yong Jeong ◽  
Kwi-Seok Ha ◽  
Won-Pyo Chang ◽  
Yong-Bum Lee ◽  
Dohee Hahn ◽  
...  
Keyword(s):  
Fast Reactor ◽  
System Analysis ◽  
Natural Circulation ◽  
Heat Removal ◽  
Circulation Loop ◽  
Ambient Atmosphere ◽  
Steady State Condition ◽  
Decay Heat ◽  
Natural Circulation Loop ◽  
Test Loop

The Korea Atomic Energy Research Institute (KAERI) is developing a Generation IV sodium-cooled fast reactor design equipped with a passive decay heat removal circuit (PDRC), which is a unique safety system in the design. The performance of the PDRC system is quite important for the safety in a simple system transient and also in an accident condition. In those situations, the heat generated in the core is transported to the ambient atmosphere by natural circulation of the PDRC loop. It is essential to investigate the performance of its heat removal capability through experiments for various operational conditions. Before the main experiments, KAERI is performing numerical studies for an evaluation of the performance of the PDRC system. First, the formation of a stable natural circulation is numerically simulated in a sodium test loop. Further, the performance of its heat removal at a steady state condition and at a transient condition is evaluated with the real design configuration in the KALIMER-600. The MARS-LMR code, which is developed for the system analysis of a liquid metal-cooled fast reactor, is applied to the analysis. In the present study, it is validated that the performance of natural circulation loop is enough to achieve the required passive heat removal for the PDRC. The most optimized modeling methodology is also searched for using various modeling approaches.

The Natural Circulation Characteristic Analysis of AP1000 IRWST

2014 ◽  
Author(s):  
Ruojun Xue ◽  
Bin Xia ◽  
Wang Mingyuan
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Exchanger ◽  
Waste Heat ◽  
Natural Circulation ◽  
Reactor Core ◽  
Heat Removal ◽  
Dead Zones ◽  
Circulation Characteristic ◽  
Heat Removal System

The natural convection passive residual heat removal system is an essential system of AP1000 nuclear power plants, which works in the non-LOCA accident. It can discharge the waste heat in the reactor core timely, and prevent the reactor accident. The In-Containment Refueling Water Storage Tank (IRWST) is one of the most important equipments of passive residual heat removal system, which supplies the hot trap to the system. The purpose of the paper is to research the natural circulation characteristic of fluid in IRWST. In this paper, FLUENT hydrodynamics analysis software was used to simulate the flow and heat-transfer characteristics of natural convection. Temperature field and flow field in different time or locations were compared to analyze the course of natural circulation. The error was evaluated by comparing the average temperature on the outlet of heat exchanger and the design temperature. The result showed that FLUENT could simulate the flow and heat-transfer characteristics of natural convection, and the error of the simulation was acceptable. In conclusion, natural convection heat exchanger of the study can discharge the waste heat in the reactor core timely. Due to the complex structure of the heat exchanger and the IRWST, the “heat-transfer dead zones” and “flow dead zones” are generated in local parts. The presence of dead zones affects the formation of natural convection. With the development of natural circulation, the temperature field and flow field in the IRWST keep stable and the temperate rise rate become slowly.

The Safety Analysis of the 600 MWe Sodium-Cooled Fast Reactor With MARS-LMR

2012 ◽  
Author(s):  
Kwi Lim Lee ◽  
Kwi Seok Ha ◽  
Hae Yong Jeong ◽  
Won Pyo Chang
Keyword(s):  
Heat Exchanger ◽  
Heat Transport ◽  
Transport System ◽  
Fast Reactor ◽  
Thermal Power ◽  
Heat Removal ◽  
Decay Heat ◽  
Metal Fuel ◽  
Heat Removal System ◽  
Independent Loops

Korea Atomic Energy Research Institute (KAERI) has been developing a conceptual design of the demonstration fast reactor (DFR), which is the pool type sodium cooled fast reactor with the thermal power of 1548.2 MW and the core loaded with metal fuel. The DFR is composed of a Primary Heat Transport System (PHTS), an Intermediate Heat Transport System (IHTS), a Steam Generating System (SGs) and a decay heat removal system (DHRS). The DHRS is composed of 2 units of Passive Decay-heat Removal Circuits (PDRC) and 2 units of Active Decay-heat Removal Circuits (ADRC). The PDRC consists of two independent loops with sodium-to-sodium Decay Heat eXchanger (DHX) and natural-draft sodium-to-Air Heat eXchanger (AHX). The ADRC consists of two independent loops with sodium-to-sodium DHX and Forced-Draft sodium-to-air Heat eXchanger (FDHX) located in the upper region of the reactor building. The PDRC is very different from that of KALIMER-600 on the points of the submerged location and the heat transfer mechanism. For the identification of safety characteristics, 5 DBE’s (Design Bases Events) are analyzed using the MARS-LMR code. The representative DBE’s are TOP (Transient of Over Power), LOF (Loss Of Flow), LOHS (Loss Of Heat Sink), Reactor Vessel Leak and Pipe Break. As a result, it is identified that the DFR were appropriately performed as designed and the temperatures of the fuel and the structure were evaluated to satisfy the criteria.

An Optimal Design Approach for the Decay Heat Removal System in PGSFR

2014 ◽  
Author(s):  
Dehee Kim ◽  
Jaehyuk Eoh ◽  
Tae-Ho Lee
Keyword(s):  
Heat Transfer ◽  
Genetic Algorithm ◽  
Heat Exchanger ◽  
Heat Removal ◽  
Design Parameters ◽  
Dimensional System ◽  
Decay Heat ◽  
Gen Iv ◽  
Heat Removal System ◽  
Removal System

Sodium-cooled Fast Reactor (SFR) is one of the generation IV (Gen-IV) nuclear reactors. Prototype Gen-IV SFR (PGSFR) is a SFR being developed in Korea Atomic Energy Research Institute (KAERI). Decay Heat Removal System (DHRS) in the PGSFR has a safety function to make shutdown the reactor under abnormal plant conditions. Single DHRS loop consists of sodium-to-sodium decay heat exchanger (DHX), helical-tube sodium-to-air heat exchanger (AHX) or finned-tube sodium-to-air heat exchanger (FHX), loop piping, and expansion vessel. The DHXs are located in the cold pool and the AHXs and FHXs are installed in the upper region of the reactor building. The DHRS loop is a closed loop and liquid sodium coolant circulates inside the loop by natural circulation head for passive system and by forced circulation head for active system. There are three independent heat transport paths in the DHRS, i.e., the DHX shell-side sodium flow path, the DHRS sodium loop path through the piping, the AHX shell-side air flow path. To design the components of the DHRS and to determine its configuration, key design parameters such as mass flow rates in each path, inlet/outlet temperatures of primary and secondary flow sides of each heat exchanger should be determined reflecting on the coupled heat transfer mechanism over the heat transfer paths. The number of design parameters is larger than that of the governing equations and optimization approach is required for compact design of the DHRS. Therefore, a genetic algorithm has been implemented to decide the optimal design point. The one-dimensional system design code which can predict heat transfer rates and pressure losses through the heat exchangers and piping calculates the objective function and the genetic algorithm code searches a global optimal point. In this paper, we present a design methodology of the DHRS, for which we have developed a system code coupling a one-dimensional system code with a genetic algorithm code. As a design result, the DHRS layouts and the sizing of the heat exchangers have been shown.

Setup of the Supercritical CO2 Test-Facility “Scarlett” for Basic Experimental Investigations of a Compact Heat Exchanger for an Innovative Decay Heat Removal System

2017 ◽  
Author(s):  
Wolfgang Flaig ◽  
Rainer Mertz ◽  
Jörg Starflinger
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Test Section ◽  
Supercritical Co2 ◽  
Power Plants ◽  
Heat Removal ◽  
Test Facility ◽  
Experimental Investigations ◽  
Decay Heat ◽  
Heat Removal System

Supercritical fluids show great potential as future coolants for nuclear reactors, thermal power and solar power plants. Compared to the subcritical condition, supercritical fluids show advantages in heat transfer due to thermodynamic properties near the critical point. This can lead to the development of more compact and more efficient components, e.g. heat exchanger and compressors. A specific field of interest is a new decay heat removal system for nuclear power plants which is based on a turbine-compressor-system with supercritical CO2 as the working fluid. In case of a station blackout this system converts the decay heat into excess electricity and low-temperature waste heat, which can be emitted to the ambient air. This scenario has already been investigated by means of the thermo-hydraulic code ATHLET, numerically demonstrating the operation of this system for more than 72 h. The practical demonstration is carried out within the Project “sCO2-HeRo”, funded by the European Commission, in which a small scale demonstration unit of the turbo compressor shall be installed at the PWR glass model at GfS, Essen, Germany. To guarantee the retrofitting of this decay heat removal system into existing nuclear power plants, the heat exchanger needs to be as compact and efficient as possible. Therefore, a diffusion welded plate heat exchanger (DWHE) was developed and manufactured at IKE. It has been designed with rectangular mini-channels (0.5–3 mm hydraulic diameter) to ensure high compactness and high heat transfer coefficients. Due to uncertainties the DWHE has to be tested in regard to the actual possible transferrable heat power and to the pressure loss. According to this demand a multipurpose facility has been built at IKE for various experimental investigations on supercritical CO2, which is in operation now. It consists of a closed loop where the CO2 is compressed to supercritical state and delivered to the test section. The test section itself can be exchanged by other ones for various investigations. After the test section, the CO2 pressure is reduced and the liquid is stored in storage tanks, from where it is evaporated and compressed again. The test facility is designed to carry out experimental investigations with CO2 mass flows up to 0.111 kg/s, pressures up to 12 MPa and temperatures up to 150 °C. The first subject of interest will be the study of the thermal behavior of a DWHE using supercritical CO2 as a working fluid close to its critical point. Experiments concerning pressure loss and heat transfer will be carried out as a start for fundamental investigation of heat transfer in mini-channels. This paper contains a detailed description of the test facility, of the first test section and first results regarding heat transfer power and pressure loss.

scholarly journals Computational Performance of Disparate Lattice Boltzmann Scenarios under Unsteady Thermal Convection Flow and Heat Transfer Simulation

Computation ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 65
Author(s):  
Aditya Dewanto Hartono ◽  
Kyuro Sasaki ◽  
Yuichi Sugai ◽  
Ronald Nguele
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Natural Convection ◽  
Lattice Boltzmann ◽  
Numerical Results ◽  
Convection And Heat Transfer ◽  
Steady State Condition ◽  
Physical Systems ◽  
Flow And Heat Transfer ◽  
Computational Performance

The present work highlights the capacity of disparate lattice Boltzmann strategies in simulating natural convection and heat transfer phenomena during the unsteady period of the flow. Within the framework of Bhatnagar-Gross-Krook collision operator, diverse lattice Boltzmann schemes emerged from two different embodiments of discrete Boltzmann expression and three distinct forcing models. Subsequently, computational performance of disparate lattice Boltzmann strategies was tested upon two different thermo-hydrodynamics configurations, namely the natural convection in a differentially-heated cavity and the Rayleigh-Bènard convection. For the purposes of exhibition and validation, the steady-state conditions of both physical systems were compared with the established numerical results from the classical computational techniques. Excellent agreements were observed for both thermo-hydrodynamics cases. Numerical results of both physical systems demonstrate the existence of considerable discrepancy in the computational characteristics of different lattice Boltzmann strategies during the unsteady period of the simulation. The corresponding disparity diminished gradually as the simulation proceeded towards a steady-state condition, where the computational profiles became almost equivalent. Variation in the discrete lattice Boltzmann expressions was identified as the primary factor that engenders the prevailed heterogeneity in the computational behaviour. Meanwhile, the contribution of distinct forcing models to the emergence of such diversity was found to be inconsequential. The findings of the present study contribute to the ventures to alleviate contemporary issues regarding proper selection of lattice Boltzmann schemes in modelling fluid flow and heat transfer phenomena.

scholarly journals Experimental and Theoretical Investigation of the Natural Convection Heat Transfer Coefficient in Phase Change Material (PCM) Based Fin-and-Tube Heat Exchanger

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 716
Author(s):  
Saulius Pakalka ◽  
Kęstutis Valančius ◽  
Giedrė Streckienė
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Natural Convection ◽  
Energy Storage ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Convection Heat Transfer Coefficient

Latent heat thermal energy storage systems allow storing large amounts of energy in relatively small volumes. Phase change materials (PCMs) are used as a latent heat storage medium. However, low thermal conductivity of most PCMs results in long melting (charging) and solidification (discharging) processes. This study focuses on the PCM melting process in a fin-and-tube type copper heat exchanger. The aim of this study is to define analytically natural convection heat transfer coefficient and compare the results with experimental data. The study shows how the local heat transfer coefficient changes in different areas of the heat exchanger and how it is affected by the choice of characteristic length and boundary conditions. It has been determined that applying the calculation method of the natural convection occurring in the channel leads to results that are closer to the experiment. Using this method, the average values of the heat transfer coefficient (have) during the entire charging process was obtained 68 W/m2K, compared to the experimental result have = 61 W/m2K. This is beneficial in the predesign stage of PCM-based thermal energy storage units.

Thermodynamic Analysis of the Internal Melt-Ice-on-Tube during Melting under Natural Convection

2014 ◽  
Vol 937 ◽  
pp. 375-380
Author(s):  
Yi Liu ◽  
Xin Chen
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Storage System ◽  
Heat Transfer Process ◽  
The Other ◽  
Ice Storage ◽  
Ice Melting ◽  
Single Tube ◽  
Initial Stage ◽  
The One

The numerical simulation of the ice melting processes in internal melt-ice-on-tube which is applied widely in the ice storage system is carried out. The dynamic mathematical models about melting are established and solved by using enthalpy method. Natural convection of the melted water in the course of melting is studied, and natural convection influences on single tube in melting heat transfer process is analyzed under the related parameters. Several conclusions are obtained:1. Because of natural convection of the melted water, the curve of melting interface is no longer a circle, but a curve changing with angle. The melting radius reaches minimum at the bottom and maximum at the top.2. The one with natural convention is compared to the other not considered. At initial stage, the influence of natural convection is smaller in the course of melting. However, the influence of natural convention increases along with melting.

scholarly journals Heat Transfer Analysis of Passive Residual Heat Removal Heat Exchanger under Natural Convection Condition in Tank

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Qiming Men ◽  
Xuesheng Wang ◽  
Xiang Zhou ◽  
Xiangyu Meng
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Thermal Stratification ◽  
Heat Removal ◽  
Heat Transfer Analysis ◽  
Average Error ◽  
Water Tank ◽  
Shaped Tube ◽  
Heat Transfer Calculation ◽  
Residual Heat

Aiming at the heat transfer calculation of the Passive Residual Heat Removal Heat Exchanger (PRHR HX), experiments on the heat transfer of C-shaped tube immerged in a water tank were performed. Comparisons of different correlation in literatures with the experimental data were carried out. It can be concluded that the Dittus-Boelter correlation provides a best-estimate fit with the experimental results. The average error is about 0.35%. For the tube outside, the McAdams correlations for both horizontal and vertical regions are best-estimated. The average errors are about 0.55% for horizontal region and about 3.28% for vertical region. The tank mixing characteristics were also investigated in present work. It can be concluded that the tank fluid rose gradually which leads to a thermal stratification phenomenon.

Sign in / Sign up

Export Citation Format

Share Document