Design principles of a nuclear and industrial HVAC of IFMIF

• Parameter of Derivate air Contamination (DAC) allows to associate the type of air ventilation.
• The construction and operation of IFMIF will be subjected to the regulations of the country in which it will be sited.
• Structures, systems and components are assigned a particular safety important components (SIC, 1–2 and Non-SIC) clarification that is based on the consequences of their failure.
• Reliability, Availability, Maintainability and Inspectability (RAMI) analysis has given a great contribution of the facility to optimize the configuration, particularly for the HVAC system.

In 2013, the IFMIF, the International Fusion Material Irradiation Facility, presently in its Engineering Validation and Engineering Design Activities (EVEDA) phase, framed by the Broader Approach Agreement between Japan and EURATOM, accomplished in 2013 its mandate to provide the engineering design of the plant on schedule [1].The IFMIF aims to qualify and characterize materials that are capable of withstanding the intense neutron flux originated in D-T reactions of future fusion reactors due to a neutron flux with a broad peak at 14 MeV, which is able to provide >20 dpa/fpy on small specimens in this EVEDA phase. The successful operation of such a challenging plant demands a careful assessment of the Conventional Facilities (CF), which have adequate redundancies to allow for the target plant availability [2].The present paper addresses the design proposed in the IFMIF Intermediate Engineering Design Report regarding the CF, particularly the IFMIF's Nuclear and Industrial HVAC design. A preliminary feasibility study, including the initial configuration, calculations and reliability/availability analysis, were performed. The nuclear HVAC design was developed progressively; first, by establishing a conceptual design, starting from the system functional description, followed by the identification of the corresponding interfacing systems and their technical requirements. Once the technical requirements were identified, safety zones were identified based on the radiation classification, frequency dose and parameter of Derivate Air Contamination (DAC). The zone color was determined to match the room's radiation classification. The system design was further developed by defining and creating a Block Diagram with basic and additional information, eventually resulting in a Process Flow Diagram concurrent with the equipment layout definition. Subsequently, we studied and developed the various Piping & instrumentation diagrams (P&ID's), air duct layout and equipment list for different air handling units, air ducting as well as a layout plan of the equipment piping, which was eventually integrated into the 3D model of the building and coordinated with others subsystems of the IFMIF.