Residual Stress Analyses by Neutron Diffraction in Irradiated Double-V Butt Welded Steel Plates

Abstract

Neutron irradiation is known to have a considerable impact on the mechanical characteristics and the behaviour of materials and components. The distribution of residual stresses is one of the properties affected by irradiation. However, because of the difficulties in performing measurements in radioactive components, not many experimental data have to date been collected. At the High Flux Reactor (HFR) of the European Commission¿s Joint Research Centre (JRC), a facility has been developed for residual stress measurements in steel specimens subjected to long-term irradiation. The objective of this development was to establish the neutron radiation induced changes in the residual stresses around welds in test pieces representative of the core shroud of boiling water reactors. Residual Stress measurements on such double-V butt welds in stainless steel plates after irradiation exposure have been performed by neutron diffraction using this facility. The comparison with measurements in non-irradiated companion specimens showed that irradiation changed the distribution of residual stresses. The results suggested that the impact of irradiation varied with the distance of the test location from the specimen surface. No conclusions could be drawn from the measurements as far as the importance of irradiation duration is concerned.