About Us  |  Contact
Mail:sales@northalloys.com
News Center

Furuncle Corrosion of Zirconium Alloy

In addition to uniform corrosion, in Zr-Sn alloy oxygen-containing 300℃ boiling water, and ≥450℃ and ≥5MP high-temperature and high-pressure steam, local corrosion will also occur. The local oxide film is round boil-like spots, that is, boil-like corrosion.

Furuncle corrosion is a limiting factor in the design of BWR. It has been proven that furuncle corrosion will not be a limiting factor for fuel rod life.

BWR operating experience has shown that boil-like corrosion has nothing to do with temperature, but is related to water chemical conditions and the cladding material itself. N in the coolant will increase the rate of boil-like corrosion. Transient coolant conductance during the first month of operation may cause severe furuncle corrosion.

Experiments show that the size of the intermetallic compound Zr (FeCrNi) will affect the corrosion of zirconium alloys.

Cumulative annealing parameter A. An increase in A means an increase in time or temperature in the α annealing phase area, so the cumulative annealing parameter is related to the size of the precipitate phase, which is a parameter that affects the performance of furuncle corrosion.

The cumulative annealing parameter A is less than 10-19 h, and the second phase obtained is fine, most of which is less than 0.1μm, and the number is large. Its resistance to furuncle corrosion is better, but relatively uniform corrosion has a higher rate;

When the cumulative annealing parameter is less than 10-10h, the second phase is larger, and its cladding has very little resistance to furuncle corrosion, but has better resistance to uniform corrosion.

Therefore, a cladding with a cumulative annealing parameter less than 10 -1 is obtained in the process for BWR, and the cumulative annealing parameter of the fuel cladding tube for PR is generally 10-18 ~10-17h.

Several hypotheses about the formation mechanism of furuncle corrosion;

1. Local solute depletion theory.

2. The furuncle spots nucleate at the hydride precipitates at the metal/oxide film interface.

3. The superficial intermetallic compound embedded in the oxide film before the transition.

4. The oxide film grows unevenly on the metal surface, which causes the local oxide film to thicken and develop into lumps, which eventually develop into round boils.
Find Better Metal for Better Future
Products
Zirconium
Titanium
Tantalum
Niobium
Molybdenum
Tungsten
Nickel
Others
Tel:+86 21 56836035
Fax:+86 21 56836035
Email:sales@northalloys.com
Address:No 188,Xinfeng Road,Shanghai China 201501
sales@northalloys.com
Copyright © 2024 North Alloys All Rights Reserved Tel:+86 21 56836035 | Overview | Products&Service | Technical Assistance | Appliance