Fuel string dynamics and pressure tube fretting corrosion in the CIRENE power channel

The paper is aimed to give an overall view of the efforts which are being pursued on the problem of fuel string dynamics and pressure tube fretting corrosion in the CIRENE reactor power channel. The experimental and theoretical studies carried out cover the following areas: mechanical characterization of the fuel bundle and of the fuel string in static and dynamic conditions; basic fretting corrosion mechanism between Zr-2 and Zr-2; fuel string vibrations induced by the two phase flow; and full scale endurance tests of the CIRENE power channel in adiabatic conditions. The RandD activities carried out in these areas are briefly presented and the main results up to now obtained are given. The points of major concern are discussed and the program of future investigations is outlined. (author)