Computerized Procedure Systems (CPSs) are operator-support tools that replace conventional paper-based procedures in nuclear power plants by providing procedural guidance and related operational information. By combining real-time plant data with automated logic, CPSs help operators carry out complex procedures more accurately and efficiently. Typical CPS functions include procedure presentation and selection, process information display, evaluation of procedural step logic, and access to soft controls or embedded functions
Small Modular Reactors (SMRs), which are gaining attention as a next-generation nuclear technology, are generally expected to incorporate high levels of automation along with their integral or modular designs and extensive reliance on passive safety features. In addition, many SMR concepts assume reduced staffing and the operation of multiple modules from a single control room, making advanced automation essential. In this environment, CPS is expected to play a central role, since operator activities in SMRs are largely procedure-based. As a result, CPS must evolve beyond a simple procedure reference tool into more active involvement in the operation through the automation.
These SMR characteristics call for a new definition of CPS levels of automation. Although several documents, including EPRI guidance and U.S. NRC reports, describe CPS functions and classify CPS types according to the degree of implemented functions, they mainly address high-level definitions of automation and do not adequately reflect the operational characteristics of SMRs. Existing levels-of-automation frameworks were originally developed for large nuclear power plants and therefore do not fully capture the cognitive support capabilities required in highly automated SMR environments.
In this light, this study proposes a practical levels-of-automation framework for CPS design in SMRs. First, CPS functions relevant to SMR characteristics are identified through a systematic review on CPSs and SMRs. Second, these functions are allocated across automation levels to develop a revised five-level taxonomy ranging from basic procedure display to integrated soft control and procedure-based automation of operational steps. The proposed framework is intended to serve as an early-stage design reference for the development and licensing of CPSs for SMRs.