SYMPOSIA PAPER Published: 01 January 1994

Experimental and Theoretical Studies of Parameters that Influence Corrosion of Zircaloy-4


Waterside corrosion of Zircaloy cladding in pressurized water reactors (PWRs) is largely dependent upon the operating parameters and microstructure of the zirconium alloys. The impact of these parameters on the corrosion kinetics of Zircaloys is investigated on the basis of empirical data and experiences that can be interpreted using existing corrosion models.

The influence of thermo-hydraulic data, heat flux, local boiling conditions, and of the growing oxide films has been studied from corrosion tests performed in static autoclaves or in out-of-pile loops. These parametric investigations are described as well as the models that were developed.

The impact of microstructure is studied from the comparison of the corrosion behavior of different Zircaloy-4 specimens corroded in out-of-pile tests. In particular, a poor corrosion resistance of an experimental Zircaloy-4 material is analyzed as a function of the microstructure close to the metal/oxide interface.

The impact of the alloy composition and primary coolant chemistry on the corrosion kinetics of Zircaloy-4 is modeled empirically or uses a mechanistic approach that proposes a series of chemical equations with a mathematical representation of the kinetics.

These proposed models are then used to investigate the corrosion behavior of Zircaloy-4 cladding in 17 by 17 plants for rods irradiated at high burnups. Higher PWR operating cycles, core average coolant temperature, power, and elevated primary coolant lithium concentrations (3.5 to 4 ppm) are then simulated and discussed in terms of Zircaloy corrosion resistance considerations.

Author Information

Billot, P
Commissariat à l'Energie Atomique, Saint Paul lez Durance, France
Robin, J-C
Commissariat à l'Energie Atomique, Saint Paul lez Durance, France
Giordano, A
Commissariat à l'Energie Atomique, Saint Paul lez Durance, France
Peybernès, J
Commissariat à l'Energie Atomique, Saint Paul lez Durance, France
Thomazet, J
FRAMATOME, Lyon, France
Amanrich, H
EDF/SEPTEN, Lyon, France
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Developed by Committee: B10
Pages: 351–377
DOI: 10.1520/STP15198S
ISBN-EB: 978-0-8031-5286-1
ISBN-13: 978-0-8031-2011-2