Concern

Another form of stress-corrosion cracking is hydrogen embrittlement. Although embrittlement of materials takes many forms, hydrogen embrittlement in high strength steels has the most devastating effect because of the catastrophic nature of the fractures when they occur. Hydrogen embrittlement is the process by which steel loses its ductility and strength due to tiny cracks that result from the internal pressure of hydrogen (H2) or methane gas (CH4), which forms at the grain boundaries. In zirconium alloys, hydrogen embrittlement is caused by zirconium hydriding. At nuclear reactor facilities, the term “hydrogen embrittlement” generally refers to the embrittlement of zirconium alloys caused by zirconium hydriding.