Operational modal analysis of flow-induced vibration of nuclear fuel rods in a turbulent axial flow

De Pauw, B.; Weijtjens, W.; Vanlanduit, S.; Van Tichelen, K.; Berghmans, F.

doi:10.1016/J.NUCENGDES.2014.11.040

Title

Operational modal analysis of flow-induced vibration of nuclear fuel rods in a turbulent axial flow

Author

De Pauw, B.

Weijtjens, W.

Vanlanduit, S.

Van Tichelen, K.

Berghmans, F.

Abstract

Flow-induced vibration of nuclear reactor fuel pins can result in mechanical noise and lead to failure of the reactor's fuel assembly. This problem can be exacerbated in the new generation of liquid heavy metal fast reactors that use a much denser and more viscous coolant in the reactor core. An investigation of the flow-induced vibration in these particular conditions is therefore essential. In this paper, we describe an analysis technique to evaluate flow-induced vibration of nuclear reactor fuel pins subjected to a turbulent axial flow of heavy metal. We deal with a single fuel pin mockup designed for the leadbismuth eutectic (LBE) cooled MYRRHA reactor which is subjected to similar flow conditions as in the reactor core. Our analysis is based on operational modal analysis (OMA) techniques. We show that the accuracy and precision of our OMA technique is higher compared to traditional methods and that it allows evaluating the evolution of modal parameters in operational conditions. We also demonstrate the possible onset of a fluid-elastic instability by tracking the modal parameters with increasing flow velocity.

Language

English

Source (journal)

Nuclear engineering and design. - Amsterdam

Publication

Amsterdam : 2015

ISSN

0029-5493

DOI

10.1016/J.NUCENGDES.2014.11.040

Volume/pages

284 (2015) , p. 19-26