Formation and Role of Gel Fractions in the Corrosion Layer of Zirconium Cladding as the First-stage Protection of the Nuclear Power Plant Fuel

 

Grant No.:

106/04/0043

Grant Agency:

Czech Science Foundation (GAČR)

Resolved in:

2004 - 2006

Principal investigator:

Ing. Zuzana Weishauptová, DrSc., Department of Geochemistry, IRSM AS CR, v.v.i.

Co-investigators:

Ing. Věra Vrtílková, UJP Praha a.s.
Ing. Olga Bláhová,PhD., The Faculty of Mechanical Engineering, University of West Bohemia in Pilsen
RNDr. J. Maixner, Central Laboratories at the Institute of Chemical Technology

Description:

Zirconium alloys are used as a material for the nuclear reactor fuel cladding. The mechanism of corrosion is influenced by the alloy used, on one hand, and by the corrosive medium to which the alloy is exposed, on the other hand. An assumption has been risen that the water medium with properties of a condensed phase at 360°C leads to formation of hydrated oxide with gel character, whereas steam medium behaving at 450°C as gas does not. The grant project is aimed a) at the differentiation of the influence of the exposure media on the corrosion nuclear fuel cladding, b) at the identification of transition form of hydrated zirconia of gel character in the reactor medium, when the gel form affects extent of the porous system and size of transport ways, and thus also input of water into the boundary of metal / corrosion layer controlling corrosion kinetics and thickness of the oxidic layer, c) at the description of the physical and physico-chemical properties characterizing the different structural forms of the corrosion layer of zirconia. According to literature research, the gel character of zirconia yet has not been studied separately in connection with reactor environment, and the quite new results obtained could further clarify mechanism of the corrosion process.

ISVAV: (What is it?)

Project in The Research and Development and Innovation System of the Czech Republic (in Czech only)