IPADeP: A Systems Engineering process for conceptual design of Tokamak sub-systems

Abstract

Engineering development of large-scale engineering systems is becoming increasingly knowledge-intensive and collaborative. The involvement of multiple, competing functionality requirements and lots of resources has imposed high expectations, and at the same time challenges, for achieving reliable, affordable design. In this contest, concept design stage results a complex and iterative process in which design tasks are highly interdependent. While design freedom is at its maximum in early design stage, product knowledge is only partially known initially and is changing over time. This research discusses the use of a systematic design method, the Iterative and Participative Axiomatic Design Process (IPADeP), for the early conceptual design stage of large-scale engineering systems. Systems Engineering focuses on how to design and manage complex systems over their life cycles. Both must begin by discovering the real problems that need to be resolved and identifying from the early stage of the design the main stakeholder requirements and customer needs. The Axiomatic Design (AD) has demonstrated its strength in various type of systems design. IPADeP provides a systematic methodology for applying AD theory in the conceptual design of large-scale engineering systems. The IPADeP process is an iterative and incremental, participative process, requirements driven. It aims to provide a systematic process to face the conceptual design activities minimizing the risk related to the uncertainty and incompleteness of the requirements and to improve the collaboration of multi-disciplinary design teams. IPADeP has been developed within the pre-conceptual design activities of the DEMOnstration fusion power plant sub-systems. Accordingly, the second main aim of this dissertation is to discuss and demonstrate the advantages in using IPADeP in large-scale engineering system, in particular for the applications concerning the design of fusion tokamak reactors. Indeed the development of tokamak sub-systems has to take into account interface, structural, functional requirements and multi-physics issues that can be completely known only during the development of the process. The conceptual design o DEMO divertor fixation system has been used in this research to prove the general efficacy of the methodological instruments considered in dealing systematically with the conceptual design stage of systems characterized by high levels of complexity and poor knowledge of the technologies.