Study of the impact of hydrides on the fracture toughness of Zr-2.5Nb alloy

Abstract

Hydrogen absorption and hydride formation in zirconium (Zr) alloys is a well-known issue and has been extensively studied in the past. Hydrogen has an impact not only on the strength but also on the fracture toughness of Zr alloys. As various Zr alloys are used for manufacturing the core components of nuclear reactors, such as nuclear fuel claddings, fuel channels, fuel assemblies, fixtures, and etc., their structural integrity has a great impact on the safety and reliability of the whole nuclear power plant. Furthermore, the hydrogen absorption ageing mechanism retains its significance not just during reactor operation but also throughout decommissioning and storage of spent nuclear fuel, especially when sufficient levels of absorbed hydrogen concentrations are reached, potentially leading to a delayed hydride cracking mechanism. Assessing the impact of hydrogen absorption on the strength of zirconium alloys typically involves time-consuming, costly, and sample-intensive experimental studies. Consequently, there is a demand for alternative research approaches. This article introduces the methodology to evaluate the fracture toughness of the Zr-2.5Nb alloy with varying hydrogen concentrations.