Alchemy: A model-based approach for 2D to 3D autonomous nuclear system design

Engineering design of nuclear power plant (NPP) piping and equipment systems frequently bypasses crucial 2D system planning, instead moving straight to 3D modeling. This often leads to designs that exceed building envelope constraints, forcing expensive and time-consuming redesigns. When 2D modeling is employed, converting system diagrams into 3D models requires labor-intensive manual workflows across incompatible proprietary tools, introducing interpretation errors and data loss at each step. No existing framework addresses end-to-end autonomous generation of Industry Foundation Classes (IFC)-compliant 3D building information models (BIMs) directly from 2D nuclear system definitions. This paper presents Alchemy, an autonomous model-based framework that closes this gap by integrating four capabilities into a single shared data model: (i) a web-based interface capturing hierarchical nuclear system topology, equipment geometry, and inter-component connectivity, (ii) a two-phase equipment layout optimization algorithm, (iii) an automated pipe routing methodology implemented via deterministic A* search and stochastic Ant Colony Optimization (ACO), and (iv) a native IFC 4.0 geometry authoring pipeline that directly instantiates building, equipment, and piping objects within a standards-compliant BIM hierarchy without proprietary software or translation artifacts. The integration of these capabilities through one shared data model, rather than any single capability in isolation, is the principal contribution, preserving system identity from the 2D diagram through to the final IFC geometry without proprietary translation. Validated on two representative pressurized-water reactor (PWR)-based reactor configurations, Alchemy generated fully connected, IFC-compliant 3D facility models satisfying all geometric and system constraints completing Case Study 1 (five equipment items, six pipe connections) in 47 s and Case Study 2 (ten equipment items, eight pipe connections) in approximately 2 min. This work represents a foundational step toward digital engineering for nuclear facility preliminary design, with future ongoing development targeting design code compliance and expanded system complexity.