Electrical Penetration Assemblies (EPAs) transfer electrical power and signals through the containment wall and ensure the containment pressure boundary is maintained during design basis accident conditions. This dual function, as a safety-related electrical and mechanical device, makes the EPA an unique nuclear component.

EPAs are configured with individual feedthrough modules that are mounted to a bulkhead flange, header plate, or canister. Feedthrough modules are constructed with electrical conductors to pass electrical signals or power, insulators, and seals in a stainless steel housing. Feedthrough modules and the bulkhead flange aperture are supplied with double redundant seals and internal nitrogen gas containment space for leakage monitoring.