EVALUATION OF FRETTING DAMAGE OF ZIRCALOY CLADDING TUBES

The work is part of the search for a technique to study the fretting p roperties of the cladding of fuel rods in nuclear reactors. The strate gy is to compare the fretting scars of specimens tested in a near-full -scale, nonradioactive simulator (so called fuel assembly endurance te st) with scars on specimens tested under well controlled conditions in the laboratory. By systematic variations of the laboratory resting pa rameters it has proved possible to achieve scars with the same type of damage characteristics as those from the fuel assembly endurance test . This makes it possible to estimate, by deduction, the parameters tha t cause fretting damage under actual sen,ice conditions in a reactor.