Research on computer-based procedure (CBP) systems has found operational advantages over paper-based procedures (PBPs) including reduced memory workload, increased automation, and fewer operator errors. A Nuclear Regulatory Commision (NRC) study (1995) found that procedure related issues have been implicated in 69% of reported events for nuclear power plants (NPPs). Despite the associated risk with existing PBPs, utilities are hesitant to be first adopters and research is needed to validate systems in the context of modernized but largely analog Generation II main control rooms. Existing implementations of CBP systems have started from the ground up and where able to have tailored operations to support CBP systems. For existing plants this is a time-consuming, expensive, and potentially risky proposition, which represents a substantial shift current operational practices. For example, plants have existing protocols for authoring and maintaining procedures that serve as administrative controls over processes. Therefore, procedures serve organizational and administrative purposes unrelated to the actual operator control of the plant. A replacement computerized system must be able to replace existing functionality and dovetail with these organizational processes. This document describes the functional characteristics and technical specification for a Computerized Procedure Engine (CPE) designed to meet the needs of modernized United States (US) NPPs. The CPE is designed with flexibility in mind to satisfy a variety of functional and research objectives.