Physical Chemical Research Group

Since zirconium alloys are essential in nuclear reactor technology, functioning as fuel cladding, extensive experimental and theoretical investigations are required to understand their corrosion properties in details to enable applying more severe operating conditions, longer service time, higher burnups, higher pH in pressurized water reactor (PWR) coolants. The high temperature hydrothermal oxidation of zirconium and the properties of the oxide layer were studied earlier with in situ and ex situ techniques. The influence of radiation damage on the oxide layer was investigated in 2008 on samples oxidised in autoclave at high temperature. A new autoclave was built for oxidation studies up to 500ºC in supercritical water with the aim of providing data for future reactor systems. For a more detailed analysis on the structure of water in thermodynamic supercritical state, the Dynamic Neutron Radiography technique is used at the Budapest Neutron Centre.

Theoretical work on the description of chemical reaction controlled diffusion processes and the numerical simulations are supporting the experimental observations.

In addition to the cladding oxidation studies, the kinetics of the accumulation of contaminants on the surfaces of structural materials at ambient temperature were also investigated, simulating the conditions of the spent fuel storage pool and the transportation cask.