The present paper deals with the analytical study, performed using the TRACE code (version 5.0), of the experiment F4.1 executed in PKL-III test facility. The test F4.1 investigates both the boron dilution occurrence and the heat transfer from primary to secondary side under natural circulation conditions (single and two phase flow) and reflux condensation (RC) mode. Boron dilution events, such as the formation of low borated slugs in the loop seals of a PWR in condition of reduced mass inventory, namely during small break loss of coolant accidents (SB-LOCA), are investigated. The relevance of boron dilution transients is connected with the need to obtain an accurate prediction of the solute particle distribution in pressurized water reactors (PWRs), since its concentration would affect the reactivity of the system. In fact the possibility that the un-borated coolant enters in the core may cause re-criticality or, even worse, power excursions. The numerical investigation has been performed by developing a complete TRACE input model of the PKL integral test facility that includes both primary and secondary systems. The aim of this work is the assessment of the TRACE code against the boron transport and the heat transfer mechanism in the different flow regimes that take place during the experiment. The accuracy of the calculation has been evaluated by qualitative and quantitative analysis. The quantification of the accuracy has been performed using the Fast Fourier Transform Based Method (FFTBM) developed at University of Pisa. The tool provides an integral representation of the accuracy quantification in the frequency domain.

Analytical study of Inherent Boron Dilution phenomenon during a Small Break LOCA scenario in a PWR-System using the TRACE v5.0 code

D'AURIA, FRANCESCO SAVERIO
2012-01-01

Abstract

The present paper deals with the analytical study, performed using the TRACE code (version 5.0), of the experiment F4.1 executed in PKL-III test facility. The test F4.1 investigates both the boron dilution occurrence and the heat transfer from primary to secondary side under natural circulation conditions (single and two phase flow) and reflux condensation (RC) mode. Boron dilution events, such as the formation of low borated slugs in the loop seals of a PWR in condition of reduced mass inventory, namely during small break loss of coolant accidents (SB-LOCA), are investigated. The relevance of boron dilution transients is connected with the need to obtain an accurate prediction of the solute particle distribution in pressurized water reactors (PWRs), since its concentration would affect the reactivity of the system. In fact the possibility that the un-borated coolant enters in the core may cause re-criticality or, even worse, power excursions. The numerical investigation has been performed by developing a complete TRACE input model of the PKL integral test facility that includes both primary and secondary systems. The aim of this work is the assessment of the TRACE code against the boron transport and the heat transfer mechanism in the different flow regimes that take place during the experiment. The accuracy of the calculation has been evaluated by qualitative and quantitative analysis. The quantification of the accuracy has been performed using the Fast Fourier Transform Based Method (FFTBM) developed at University of Pisa. The tool provides an integral representation of the accuracy quantification in the frequency domain.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/831382
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