A realistic approach for the assessment of the consequences of heterogeneous boron dilution events in pressurized water reactors


A realistic approach for the assessment of the consequences of heterogeneous boron dilution events in pressurized water reactors

Kliem, S.; Grahn, A.; Bilodid, Y.; Höhne, T.

In order to compensate the excess reactivity over the fuel cycle in pressurized water reactors, boric acid is added to the reactor coolant. The formation and the subse-quent transportation towards the core of coolant with reduced boron concentration can lead to a positive reactivity insertion into the reactor core. In this paper a new approach of dealing with such heterogeneous boron dilution scenarios is presented. This approach is based on the use of computational fluid dynamics methods for the whole reactor pressure vessel with direct coupling of a neutron-kinetic model of the reactor core.
The application of this approach is demonstrated on a main coolant pump start scenario for hot-shutdown conditions using the coupled DYN3D/ANSYS CFX code.

Keywords: Boron dilution; DYN3D; CFD; neutron kinetics/thermal hydraulics coupling; PWR

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Permalink: https://www.hzdr.de/publications/Publ-27942
Publ.-Id: 27942