Thermal Performance of Intermediate Heat Exchanger during High-Temperature Continuous Operation in HTTR

Tochio, Daisuke; Nakagawa, Shigeaki

doi:10.1080/18811248.2011.9711828

Cited by 10 publications

(3 citation statements)

References 4 publications

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“…This heat exchanger is named as (IHX). 18 The secondary helium gas in IHX is heated up to~885 C, and it enters into a second heat exchanger (second HX) which is a 0.7 MWth horizontal helically-coiled type heat exchanger devoted to supply heat to the hydrogen plant. 1 The hot helium that passes through the second HX goes to a mixing header at 832 C. Then, it enters the turbine at 568 C, and it is expanded up to 493 C. The expanded helium goes to a recuperator to recover some of the energy exhausted from the turbine and returns to the mixing header at 453 C. Then, the helium exiting the recuperator enters a precooler to decrease its temperature from 117 C to 25 C needed to enter the compressor.…”

Section: System Descriptionmentioning

confidence: 99%

Development of a zero‐dimensional dynamic simulator of a power conversion system with a high‐temperature gas reactor

Juárez‐Martínez

Espinosa-Paredes

2021

Int J Energy Res

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The HTTR-GT/H2 plant is a nuclear power cogeneration plant for hydrogen production. The hydrogen production is based on the thermochemical sulfuriodine cycle able to produce about 30 NM 3 /h of hydrogen and 15 Nm 3 /h of oxygen. The power conversion system consists of a Bryton-cycle helium gas turbine designed to produce 1 MWe electric of power output, and the source of heat is the high temperature engineering test reactor designed by the Japan Atomic Energy Agency. In this work, a preliminary dynamic simulator for the power conversion system was developed. The plant simulator couples the dynamics of the nuclear reactor, the internal heat exchanger, and plant components, such as heat exchangers, coolers, recuperators, compressors, and turbines. Despite the simplicity of modeling, the use of zero-dimensional models showed a good agreement with the reported values, being 0.67% of difference for reactor's power, 0.22% of difference for the coolant outlet temperature, and the differences of the conversion system components compared to the reference ranges between 0.0 and 0.26%.

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Section: System Descriptionmentioning

confidence: 99%

Development of a zero‐dimensional dynamic simulator of a power conversion system with a high‐temperature gas reactor

Juárez‐Martínez

Espinosa-Paredes

2021

Int J Energy Res

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“…The reactor outlet temperature decreases because of the reduction of reactor power and startup of ACS. The detailed description of these HTTR tests can be found in the reports [4,5].…”

Section: Test Conditionsmentioning

confidence: 99%

Validation and application of thermal hydraulic system code for analysis of helically coiled heat exchanger in high-temperature environment

Satō

Ohashi

Nakagawa

et al. 2014

Journal of Nuclear Science and Technology

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A qualification of the thermal hydraulic system code RELAP5 (reactor excursion leak analysis program) is conducted for the analysis of helically coiled heat exchangers used in a high-temperature environment. A set of closure models based on the past separate effect test are suggested and validated against the measured data in the high temperature engineering test reactor (HTTR). The modified code is then tested for the analysis of a representative nuclear hydrogen production system. The comparison of calculated and measured data with steady-state operation showed that the original heat transfer package in RELAP5 significantly underpredicts the peak heat transfer tube temperature in the intermediate heat exchanger (IHX), particularly when the inlet helium gas temperature exceeds 600• C. In contrast, the prediction with the suggested model generally agreed well. Lower prediction of peak temperature was observed in outer shell due to the modeling capability in system codes. However, those and the other results from the analysis of the HTTR-IS system revealed that the simplification of the heat structure geometry in IHX with low operating shell temperature is acceptable. In conclusion, this study explores the applicability of the system code to safety analysis of nuclear hydrogen production systems by means of a newly introduced closure model.

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“…To obtain a comprehensive definition of the tridimensional models, the authors gathered data from many different papers to reproduce accurately the component (see, as an example, Takeda et al [21]). Some sketches help us in modeling the hot head and its insulation thickness [22] and with the plates for enhancing heat exchange [18]. In our simulations, we assume to use this component coupled to a I-S thermochemical system; however, it is important to underline that this heat exchanger can be used for each application that required a high temperature reactor (HTR, VHTR) coupled with a high temperatures chemical process.…”

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confidence: 99%

Nuclear Hydrogen Production: Modeling and Preliminary Optimization of a Helical Tube Heat Exchanger

2021

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Hydrogen production is a topical issue in an energy scenario where decarbonization is a priority, especially with reference to the transport sector that has a great weight on global emissions. Starting from this consideration, GIF (Generation-IV International Forum) investigated the possibility to produce hydrogen by nuclear energy. The “classic” strategy is based on the use of nuclear as energy source for the electrolysis; but on the medium-long term, a more sustainable and smart approach could be founded on the use of thermochemical processes (e.g., I-S) that require a direct coupling of a chemical plant to a nuclear reactor. In order to develop this strategy, it is mandatory to design and optimize all the key components involved in this complex plant. In this study, we developed the 3D-CAD and CFD models of the intermediate heat exchanger (IHX) installed in the Japanese HTTR nuclear power plant. This component is extremely important for both the safety of the two plants and the stability of the whole hydrogen production plant. Initially, our model (developed by AutoCAD 3D and implemented in Star CCM+) was validated on the basis of experimental data available in literature; then, an initial optimization of the IHX testing innovative materials, such as Alloy 617 and ODS–MA754, and a different primary coolant (supercritical CO2) was performed.

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Thermal Performance of Intermediate Heat Exchanger during High-Temperature Continuous Operation in HTTR

Cited by 10 publications

References 4 publications

Development of a zero‐dimensional dynamic simulator of a power conversion system with a high‐temperature gas reactor

Development of a zero‐dimensional dynamic simulator of a power conversion system with a high‐temperature gas reactor

Validation and application of thermal hydraulic system code for analysis of helically coiled heat exchanger in high-temperature environment

Nuclear Hydrogen Production: Modeling and Preliminary Optimization of a Helical Tube Heat Exchanger

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