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

2018 ◽  
Vol 4 (3) ◽  
Author(s):  
Wolfgang Flaig ◽  
Rainer Mertz ◽  
Joerg Starflinger
Keyword(s):  
Heat Exchanger ◽  
Supercritical Co2 ◽  
Nuclear Power ◽  
Power Plants ◽  
Heat Removal ◽  
Test Facility ◽  
Experimental Investigations ◽  
Decay Heat ◽  
Heat Removal System ◽  
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. A specific field of interest is an innovative 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 severe accident, this system converts the decay heat into excess electricity and low-temperature waste heat, which can be emitted to the ambient air. To guarantee the retrofitting of this decay heat removal system into existing nuclear power plants, the heat exchanger (HE) needs to be as compact and efficient as possible. Therefore, a diffusion-bonded plate heat exchanger (DBHE) with mini channels was developed and manufactured. This DBHE was tested to gain data of the transferable heat power and the pressure loss. A multipurpose facility has been built at Institut für Kernenergetik und Energiesysteme (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 a test section in which the experiments are run. 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. This paper describes the development and setup of the facility as well as the first experimental investigation.

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.

Experimental Research on Non-Condensable Gases Effects in Passive Decay Heat Removal System

2016 ◽  
Author(s):  
Yang Liu ◽  
Haijun Jia ◽  
Li Weihua
Keyword(s):  
High Pressure ◽  
Heat Removal ◽  
Volume Ratio ◽  
Test Facility ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Decay Heat ◽  
Optimizing Design ◽  
Heat Removal System ◽  
Removal System

Passive decay heat removal (PDHR) system is important to the safety of integral pressurized water reactor (IPWR). In small break LOCA sequence, the depressurization of the reactor pressure vessel (RPV) is achieved by the PDHR that remove the decay heat by condensing steam directly through the SGs inside the RPV at high pressure. The non-condensable gases in the RPV significantly weaken the heat transfer capability of PDHR. This paper focus on the non-condensable gas effects in passive decay heat removal system at high pressure. A series of experiments are conducted in the Institute of Nuclear and New Energy Technology test facility with various heating power and non-condensable gas volume ratio. The results are significant to the optimizing design of the PDHR and the safety operation of the IPWR.

Cycle Calculations of a Small-Scale Heat Removal System With Supercritical CO2 As Working Fluid

2017 ◽  
Author(s):  
Marcel Strätz ◽  
Jörg Starflinger ◽  
Rainer Mertz ◽  
Michael Seewald ◽  
Sebastian Schuster ◽  
...  
Keyword(s):  
Power Plant ◽  
Supercritical Co2 ◽  
Heat Removal ◽  
Working Fluid ◽  
Small Scale ◽  
Brayton Cycle ◽  
Additional Heat ◽  
Decay Heat ◽  
Heat Removal System ◽  
Removal System

In case of an accident in a nuclear power plant with combined initiating events, (loss of ultimate heat sink and station blackout) additional heat removal system could transfer the decay heat from the core to and diverse ultimate heat sink. On additional heat removal system, which is based upon a Brayton cycle with supercritical CO2 as working fluid, is currently investigated within an EU-funded project, sCO2-HeRo (Supercritical carbon dioxide heat removal system). It shall serve as a self-launching, self-propelling and self-sustaining decay heat removal system to be used in severe accident scenarios. Since a Brayton cycle produces more electric power that it consumes, the excess electric power can be used inside the power plant, e.g. recharging batteries. A small-scale demonstrator will be attached to the PWR glass model at Gesellschaft für Simulatorforschung GfS, Essen, Germany. In order to design and build this small-scale model, cycle calculations are performed to determine the design parameters from which a layout can be derived.

Industrial Technical Development and Qualification of Highly Efficient Stainless Steel Plates and Fins Heat Exchanger for Heat Removal Supercritical CO2 Brayton Cycle Applied to Nuclear Power Plants

2020 ◽  
Author(s):  
Sarah Tioual-Demange ◽  
Gaëtan Bergin ◽  
Thierry Mazet ◽  
Luc de Camas
Keyword(s):  
Stainless Steel ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Supercritical Co2 ◽  
Nuclear Power ◽  
Power Plants ◽  
Heat Removal ◽  
Eutectic Phase ◽  
Steel Plates ◽  
Brayton Cycle

Abstract The sCO2-4-NPP european project aims to develop an innovative technology based on supercritical CO2 (sCO2) for heat removal to improve the safety of current and future nuclear power plants. The heat removal from the reactor core will be achieved with multiple highly compact self-propellant, self-launching, and self-sustaining cooling system modules, powered by a sCO2 Brayton cycle. Heat exchangers are one of the key components required for advanced Brayton cycles using supercritical CO2. Fives Cryo company, a brazed plates and fins heat exchangers manufacturer, with its expertise in thermal and hydraulic design and brazing fabrication is developing compact, and highly efficient stainless steel heat exchanger solution for sCO2 power cycles, thanks to their heat exchange capability with low pinch and high available flow sections. The aim of the development of this specific heat exchanger technology is to achieve an elevated degree of regeneration. For this matter, plates and fins heat exchanger is a very interesting solution to meet the desired thermal duty with low pressure drop leading to a reduction in size and capital cost. The enhancement of the mechanical integrity of plates and fins heat exchanger equipment would lead to compete with, and even outweigh, printed circuit heat exchangers technology, classically used for sCO2 Brayton cycles. sCO2 cycle conditions expose heat exchangers to severe conditions. Base material selection is essential, and for cost reasons, it is important to keep affordable heat-resistant austenitic stainless steel grades, much cheaper than a nickel-based alloy. Another advantage of high compactness of plates and fins heat exchangers is the diminution of the amount of material used in the heat exchanger manufacturing, decreasing even more its cost. The challenge here is to qualify stainless steel plates and fins heat exchangers mechanical resistance, at cycle operating conditions, and meet with pressure vessels codes and regulations according to nuclear requirements. One critical point in the development of the heat exchangers is the design of the fins. As secondary surface, they allow the maximization of heat transfer at low pressure drop. At the same time mechanical strength has to be guaranteed. To withstand high pressure, fins thickness has to be significant, which makes the implementation complicated. Efforts were dedicated to successfully obtain an optimal shape. Forming of fins was therefore improved compared to conventional techniques. Important work was undertaken to define industrial settings to flatten the top of the fins leading to a maximum contact between the brazing alloy and the fins. Consequently brazed joints quantity is minimized inducing a diminution of the presence of eutectic phase, which is structurally brittle and limits the mechanical strength of the construction. A metallurgical study brings other elements leading to the prevention of premature rupture of the brazed structure. The idea is to determine an optimized solidification path and to identify a temperature range and holding time where the brazed joint is almost free of eutectic phase during the assembly process in the vacuum furnace.

Generic Experimental Investigations of Thermohydraulic Instabilities With Void Fraction Measurement at Natural Circulation Test Facility Geneva

2014 ◽  
Author(s):  
Tim Cloppenborg ◽  
Christoph Schuster ◽  
Antonio Hurtado
Keyword(s):  
Void Fraction ◽  
Power Plants ◽  
Natural Circulation ◽  
Saturation Temperature ◽  
Heat Removal ◽  
Open Loop ◽  
Test Facility ◽  
Experimental Investigations ◽  
Decay Heat ◽  
System Pressure

Passive systems like natural circulation (NC) loops can offer reliable and cost efficient alternatives to common active systems for decay heat removal in nuclear power plants. During the transition between stable single and stable two phase flows, instabilities e. g. flashing and geysering may occur in the riser due to low system pressure and saturation temperature conditions. These instabilities may cause severe stress to the system components. This paper presented some results of the study on the decay heat removal system based on natural circulation, performed on the open loop NC test facility GENEVA, built at TU Dresden in 2013. 16 probes were used to determine void fraction along the riser on nine different levels in high time and spatial resolution, and stability maps was created for riser with inner diameters of 20 mm and 38 mm and up to 85 kW evaporator power.

Transient Analyses of Passive Residual Heat Removal System of 10MW Molten Salt Reactor Experiment

2014 ◽  
Vol 953-954 ◽  
pp. 621-626
Author(s):  
Hang Bin Zhao ◽  
Chang Qi Yan ◽  
Li Cheng Sun ◽  
Kai Bin Zhao
Keyword(s):  
Molten Salt ◽  
Power Plants ◽  
Heat Removal ◽  
Molten Salt Reactor ◽  
Inherent Safety ◽  
Decay Heat ◽  
Reactor Experiment ◽  
Heat Removal System ◽  
Removal System ◽  
Residual Heat

In order to improve the inherent safety of the Molten Salt Reactor (MSR), a concept of passive residual heat removal system (PRHRS) for the 10MW Molten Salt Reactor Experiment (MSRE) was put forward. Its transient characteristics were investigated by developing a model of it using C++ code. The effects of environmental temperature, finned tube number and chimney height on the PRHRS were analyzed. The results show that the PRHRS can remove the decay heat timely. Three natural circulations are established in the PRHRS when it begins to operate. With the decay heat power reducing, the PRHRS can automatically adjust its heat removal ability. It needs not any external power for the PRHRS to operate, which enhances the inherent safety and reliability of the reactor, especially under the condition that power plants lose power.

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.

Pre-design of an innovative passive decay heat removal system for ATRIUM AMR-SFR

2021 ◽  
Vol 378 ◽  
pp. 111259
Author(s):  
A. Pantano ◽  
P. Gauthe ◽  
M. Errigo ◽  
P. Sciora
Keyword(s):  
Heat Removal ◽  
Decay Heat ◽  
Heat Removal System ◽  
Removal System
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