Evaluation of a detailed radiation heat transfer model in a high temperature reactor systems simulation model

Antwerpen, H.J. van; Greyvenstein, Gideon P.

doi:10.1016/j.nucengdes.2008.02.020

Cited by 10 publications

(11 citation statements)

References 2 publications

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“…The cooling system consists of twenty-five cooling panels each one containing nine risers. Since the majority of the heat in the cavity is transferred by radiation [15] the riser panels may include additional features to enhance the radiation heat transfer. These include stainless steel fins, welded along the side of two adjacent risers, and shield, and additional thin panel welded on the back of the risers wall.…”

Section: Yearmentioning

confidence: 99%

“…Previous studies [15] and experimental activities conducted on similar facilities [23], supplied important information on the heat transfer mechanisms in the reactor cavity that were accounted during the scaling of the experimental facility.…”

Section: Figure 12 Typical Reactor Cavity Internals and Rccs Layoutmentioning

confidence: 99%

“…Since heat structures in RELAP5-3D cannot be specified in more than one enclosure, specific assumptions were necessary in order to overcome the code limitation and guarantee an accurate modeling of the cavity heat transfer mechanisms. Previous publications [15] and experimental work conducted in similar RCCS facilities [23], have shown that radiation is the predominant heat transfer mechanism in the reactor cavity, carrying almost 80% of the total heat transferred to the risers panels. For this reason the radiation enclosure was preferred and defined in the input deck to account for the radiation heat transfer between the heat structure simulating the reactor vessel (HS 101), and the heat structures simulating the risers front pips and fins (HS 201-9).…”

Section: Vii13 Reactor Cavitymentioning

confidence: 99%

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CFD Model Development and validation for High Temperature Gas Cooled Reactor Cavity Cooling System (RCCS) Applications

Hassan

Corradini²,

Tokuhiro³

et al. 2014

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The Reactor Cavity Cooling System (RCCS) is a passive safety system that will be incorporated in the VTHR design. The system was designed to remove the heat from the reactor cavity and maintain the temperature of structures and concrete walls under desired limits during normal operation (steady-state) and accident scenarios. A small scale (1:23) water-cooled experimental facility was scaled, designed, and constructed in order to study the complex thermohydraulic phenomena taking place in the RCCS during steady-state and transient conditions. The facility represents a portion of the reactor vessel with nine stainless steel coolant risers and utilizes water as coolant. The facility was equipped with instrumentation to measure temperatures and flow rates and a general verification was completed during the shakedown. A model of the experimental facility was prepared using RELAP5-3D and simulations were performed to validate the scaling procedure. The experimental data produced during the steady-state run were compared with the simulation results obtained using RELAP5-3D. The overall behavior of the facility met the expectations. The facility capabilities were confirmed to be very promising in performing additional experimental tests, including flow visualization, and produce data for code validation.

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Section: Yearmentioning

confidence: 99%

Section: Figure 12 Typical Reactor Cavity Internals and Rccs Layoutmentioning

confidence: 99%

Section: Vii13 Reactor Cavitymentioning

confidence: 99%

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CFD Model Development and validation for High Temperature Gas Cooled Reactor Cavity Cooling System (RCCS) Applications

Hassan

Corradini²,

Tokuhiro³

et al. 2014

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“…Flame radiation is also very important in the context of firefighter safety and wildland-urban interface fire problems. The geometrical view or configuration factor plays a crucial role in radiative heat transfer simulations (Van Antwerpen and Greyvenstein, 2008;Vujičić et al, 2006). Configuration factors depend on the shape and orientation of the surfaces as well as the distance between them (Molla et al, 2011;Walker et al, 2010).…”

Section: Estimation Of Configuration Factor For Radiationmentioning

confidence: 99%

Estimation of Configuration Factor for Radiation From a Rectangle to a Parallel Small Element of Surface Lying on the Perpendicular to a Corner of the Radiator

Bahadori

Zendehboudi

Zahedi

et al. 2013

Chemical Engineering Communications

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To calculate the radiant intensity at a point distant from a radiator, a geometrical or configuration factor must be used. If the temperature is known, then the emissive power can be calculated using the mean equivalent beam length, but before the radiant heat flux at a distance can be estimated, a configuration factor must be calculated. In this article a simple predictive tool is developed to estimate the configuration factor for a geometry including a receiving element lying on the perpendicular to one corner of a radiant rectangle. The results are found to be in excellent agreement with reported data in the literature with average absolute deviation being around 2%. The results can be used in follow up calculations to estimate heat fluxes on surfaces exposed to radiation. The tool developed in this study can be of immense practical value for engineers as a quick check on the configuration factor for a geometry including a receiving element lying on the perpendicular to one corner of a radiant rectangle without opting for any experimental trials. In particular, engineers would find the approach to be user-friendly with transparent calculations involving no complex expressions.

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“…The system can operate in active mode by removing the heat from the water in the tanks via an active secondary heat removal system, or in passive mode by boiling the water for approximately 72 hours. A small fraction of the heat produced in the core is released into the reactor cavity, mostly by radiation [4] and convection, and ultimately transferred to the RCCS water, flowing upward through vertical risers. Water coming from different risers is collected in horizontal headers or manifolds and then reaches the water tanks located on top of the reactor building, mixes with cold water, and comes back into the reactor cavity.…”

Section: Introductionmentioning

confidence: 99%

Modeling the thermal–hydraulic behavior of the reactor cavity cooling system using RELAP5-3D

Vaghetto¹,

Hassan²

2014

Annals of Nuclear Energy

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The Very High Temperature Gas-Cooled Reactor (VHTR), one of the six proposed designs for the next generation nuclear reactor, was conceived to achieve high temperatures to support industrial applications and power generation. Due to the high temperature reached during normal operation, the design included new passive safety systems. The Reactor Cavity Cooling System (RCCS) is a new passive safety system designed to remove the heat from the reactor cavity during normal operation (steady-state) and accident scenarios. Computational tools such as system codes have been selected to simulate the reactor system and, in particular, the new safety components. The capabilities of these codes are being investigated to verify their ability in predicting the phenomena involved in the RCCS operation during steady-state and accident conditions. A RELAP5-3D input model of a small scale water-cooled experimental facility was prepared to simulate steady-state. The simulation results were compared with data produced during the experimental steady-state run. The results obtained and presented in the paper showed a good agreement of the code prediction with the experimental data. The paper also provides a set of modeling techniques to overcome some of the limitations of the current version of the computer code in simulating complex geometries with combined heat transfer mechanisms in the reactor cavity of the VHTR.

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Evaluation of a detailed radiation heat transfer model in a high temperature reactor systems simulation model

Cited by 10 publications

References 2 publications

CFD Model Development and validation for High Temperature Gas Cooled Reactor Cavity Cooling System (RCCS) Applications

CFD Model Development and validation for High Temperature Gas Cooled Reactor Cavity Cooling System (RCCS) Applications

Estimation of Configuration Factor for Radiation From a Rectangle to a Parallel Small Element of Surface Lying on the Perpendicular to a Corner of the Radiator

Modeling the thermal–hydraulic behavior of the reactor cavity cooling system using RELAP5-3D

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