On Debris-Fretting Impact—The Study of Oxide and Chromium Layer Application

Abstract

The fretting phenomenon was responsible for over 50% of fuel failure cases in the years 2010–2015 according to International Atomic Energy Agency (IAEA). It shows the scale of the problem for the nuclear power generation sector. A big share of this issue is related to debris fretting. Although debris fretting has been studied for decades, the available R&D information is scarce. The presented paper summarizes the work performed in the Research Center Řež (CVŘ) on Zr–1%Nb alloy tube specimens covered with protective coatings—passivation oxide layer and pure chromium layer. The tests included the simulation of debris-fretting conditions and detailed analysis using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and focused ion beam (FIB). Those experiments are a part of a wider project devoted to the research in the specification of the fretting wear increase after applying the protective layer. The first outputs show the positive impact even in the case of an oxide layer's presence on the cladding surface.