Fault Tree and Importance Measure Analysis of a PEM Electrolyzer for Hydrogen Production at a Nuclear Power Plant

Pilot projects to generate hydrogen using proton exchange membrane (PEM) electrolyzers coupled to nuclear power plants (NPPs) began in 2022, with further developments anticipated over the next decade. However, the co-location of electrolyzers with NPPs requires an understanding and mitigation of potential risks. In this work, we identify and rank failure contributors for a 1 MW PEM electrolysis system. We used fault trees to define the component failure logic, parameterized them with generic data, and calculated failure frequencies and minimal cut sets for four top events: hydrogen release, oxygen release, nitrogen release, and hydrogen and oxygen mixing. We use risk reduction worth importance measures to determine the most risk-significant components. The results provide insight into primary risk drivers in PEM electrolyzer systems and provide the foundational steps towards quantitative risk assessment of large-scale PEM electrolyzers at NPPs. The results include recommended riskmitigation actions, include recommendations about design, maintenance, and monitoring strategies.