Scaling of natural circulation in PWR systems

D'Auria, Francesco Saverio; Galassi, G. M.; Vigni, P.; Calastri, A

doi:10.1016/0029-5493(91)90265-j

Cited by 32 publications

(7 citation statements)

References 7 publications

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“…As already showed by the previous examples (other can be got from, e.g., [8,9]), the NCFM constitutes an advantageous tool to depict the NC capability in removing the core power.…”

Section: Application To the Psb-vver Facilitymentioning

confidence: 86%

“…In this view, a quite large database has been created collecting the experimental measurements from various facilities. The NC scenarios occurring for different values of the primary system mass inventory were considered (reference is made to both singlephase and two-phase natural circulation) by gathering and analyzing data from the following PWR simulators: Semiscale, Spes, Lobi, Bethsy, Pkl, and Lstf [1].…”

Section: Introductionmentioning

confidence: 99%

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Use of the Natural Circulation Flow Map for Natural Circulation Systems Evaluation

Cherubini

Giannotti

Araneo

et al. 2008

Science and Technology of Nuclear Installations

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The aim of this paper is to collect and resume the work done to build and develop, at the University of Pisa, an engineering tool related to the natural circulation. After a brief description of the different loop flow regimes in single phase and two phase, the derivation of a suitable tool to judge the NC performance in a generic system is presented. Finally, an extensive comparison among the NC performance of various nuclear power plants having different design is done to show a practical application of the NC flow map.

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“…As already showed by the previous examples (other can be got from, e.g., [8,9]), the NCFM constitutes an advantageous tool to depict the NC capability in removing the core power.…”

Section: Application To the Psb-vver Facilitymentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Use of the Natural Circulation Flow Map for Natural Circulation Systems Evaluation

Cherubini

Giannotti

Araneo

et al. 2008

Science and Technology of Nuclear Installations

Self Cite

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“…Three of those thermocouples, i.e., TC3, TC4, and TC5, were located in the heater, and the other three, i.e., TC10, TC11, and TC12, in the cooler. The flow rate was calculated using data measured by those six thermocouples and inserted into equation 1[ [12][13][14]16].…”

Section: Calculationmentioning

confidence: 99%

“…Moreover, the stability and instability flow oscillation in the loop of natural circulation have been investigated through experiments and computer simulations [9,10]. The phenomenon of natural circulation under general geometries and its applications have been investigated by Vijayan et al [2,9], Zvirin [11], and D'Auria et al [12]. Their research activities were conducted in rectangular-shaped pipes with open and closed loops and steady state conditions.…”

Section: Introduction mentioning

confidence: 99%

An Experimental Analysis on Nusselt Number of Natural Circulation Flow in Transient Condition Based on the Height Differences between Heater and Cooler

et al. 2018

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A better understanding on the phenomenon of natural circulation flow for cooling systems is necessary prior to improving the safety of nuclear power plant, not only in normal operation but also in accident conditions. One way to understand this phenomenon is by analyzing the Nusselt number in various geometrical dimensions through experimentation. The purpose of this study is to understand natural circulation phenomenon in transient condition by varying height differences between heater and cooler. To achieve this purpose, an experiment apparatus called NC-Queen was developed and arranged to enable three variations of height differences between heater and cooler, i.e., 1.4 m, 1.0 m, and 0.3 m. It is made of a stainless steel tube with a diameter of 1 inch, arranged in rectangular shape 6.4 m in length, and uses water as coolant. The initial temperature of the heater was set at 90 °C. The Nusselt number was obtained by calculating the flow rate as a function of transient temperature. The results confirm that height differences affect thermal properties and flow region based kinetics characteristics of water. In initial condition, decreasing height difference from 1.4 m to 1.0 m resulted in flow rate reduction of 16.7 %, while decreasing height difference from 1.4 m to 0.3 m resulted in a 39.1 % flow rate reduction. In final condition, the flow rate reductions were 75 % and 82.6 %, respectively. Meanwhile, in initial condition, the Nusselt number for height difference reduction from 1.4 m to 1.0 m and from 1.4 m to 0.3 m decreased by 30.5 % and 74.6 %, respectively, while for final condition, the Nusselt number decreased by 11.9 % and 67.4 %, respectively. The new constants in relationship between Nusselt number and the height difference are a = 20.06 and b = 0.56. The dominance of turbulent flow provides a good safety margin with indications of the large amount of heat released.

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“…2), includes the logical steps hereafter listed 1) Overview of previous experiments executed in PSB-VVER, part of the OECD Project (5) in progress, of similar experiments performed in other test facilities and of data available from NPP. This implied the selection of counterpart and of similar tests (6), (7), (8), (9) .…”

Section: The Procedures For Test Designmentioning

confidence: 99%

The Design of PSB-VVER Experiments Relevant to Accident Management

Nevo

D'Auria

Mazzini

et al. 2008

JPES

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Experimental programs carried-out in integral test facilities are relevant for validating the best estimate thermal-hydraulic codes (1) , which are used for accident analyses, design of accident management procedures, licensing of nuclear power plants, etc. The validation process, in fact, is based on well designed experiments. It consists in the comparison of the measured and calculated parameters and the determination whether a computer code has an adequate capability in predicting the major phenomena expected to occur in the course of transient and/or accidents. University of Pisa was responsible of the numerical design of the 12 experiments executed in PSB-VVER facility (2) , operated at Electrogorsk Research and Engineering Center (Russia), in the framework of the TACIS 2.03/97 Contract 3.03.03 Part A, EC financed (3) . The paper describes the methodology adopted at University of Pisa, starting form the scenarios foreseen in the final test matrix until the execution of the experiments. This process considers three key topics: a) the scaling issue and the simulation, with unavoidable distortions, of the expected performance of the reference nuclear power plants; b) the code assessment process involving the identification of phenomena challenging the code models; c) the features of the concerned integral test facility (scaling limitations, control logics, data acquisition system, instrumentation, etc.). The activities performed in this respect are discussed, and emphasis is also given to the relevance of the thermal losses to the environment. This issue affects particularly the small scaled facilities and has relevance on the scaling approach related to the power and volume of the facility.

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Scaling of natural circulation in PWR systems

Cited by 32 publications

References 7 publications

Use of the Natural Circulation Flow Map for Natural Circulation Systems Evaluation

Use of the Natural Circulation Flow Map for Natural Circulation Systems Evaluation

An Experimental Analysis on Nusselt Number of Natural Circulation Flow in Transient Condition Based on the Height Differences between Heater and Cooler

The Design of PSB-VVER Experiments Relevant to Accident Management

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