Fusion Engineering and Design 103 (2016) 81–84
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Design principles of a nuclear and industrial HVAC of IFMIF Giuseppe Pruneri a,∗ , A. Ibarra b , R. Heidinger c , J. Knaster d , M. Sugimoto e a
IFMIF/EVEDA, Project Team, Rokkasho, Japan CIEMAT, Madrid, Spain c F4E, Garching, Germany d IFMIF/EVEDA Project Team, Rokkasho, Japan e JAEA, Rokkasho, Japan b
h i g h l i g h t s • 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.
a r t i c l e
i n f o
Article history: Received 17 August 2015 Received in revised form 10 December 2015 Accepted 10 December 2015 Keywords: IFMIF EVEDA HVAC
a b s t r a c t 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. © 2015 Elsevier B.V. All rights reserved.
∗ Corresponding author at: Consorzio RFX, (ENEA-CNR-Padua University-INFN-Acciaierie Venete) Italy. http://dx.doi.org/10.1016/j.fusengdes.2015.12.021 0920-3796/© 2015 Elsevier B.V. All rights reserved.
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1. Introduction IFMIF will generate a neutron flux with a broad peak at 14 MeV of the Li (d,xn) nuclear reactions generated by parallel deuteron beams colliding onto a liquid lithium jet. The two accelerators will generate beams of 40 MeV and a current of 125 mA, each in CW mode, with a common footprint of 200 mm × 50 mm [1]. Fig. 1 shows the schematic configuration of the IFMIF plant divided into five facilities: Accelerator facility, Test facility, Lithium facility, Postirradiation Examination facility and Conventional Facility. The last facility, “Conventional Facility”, and more specifically the Nuclear and Industrial HVAC Design Principles, is the topic of this article. The main function of the Heating, Ventilation and Air Conditioning (HVAC) System is to provide sufficient air throughput to ensure acceptable air quality for the continuous access of personnel to selected areas of the IFMIF. The served areas include areas where the contamination risk is excluded (Industrial areas) as well as those with a contamination risk (Nuclear areas). An important function is to assume dynamic confinement, i.e., a pressure differential between contamination zones. HVAC systems in potentially contaminated areas have the safety function of protecting both the personnel and the environment from the uncontrolled release of radioactive materials. Therefore, the HVAC systems are designed for high availability and easy maintenance. The HVAC systems do not serve the hot cells and glove boxes operating in an inert gas atmosphere, which require closed loop atmospheres with a decontamination system that are maintained under control the contents of tritium and other gas impurities. Each HVAC system is capable ensuring comfortable environmental conditions for the working staff of the plant and the appropriate thermo-hygrometric parameters for the equipment housed on the IFMIF premises. Furthermore, each HVAC system will protect workers and the environment
from contacting activated particles (in the form of chips, dust, aerosol, and activated air) due to the uncontrolled release from high potential and/or permanent contamination hazard rooms to low contamination areas or to the environment (this concept is detailed by ISO 17873:2014 [3] and is referred to as Dynamic Confinement).
2. System function and basic configuration The HVAC System will thus be designed to perform the following key functions: • Supply water to the humidification coils of the Air Handling Units (AHUs). • Condition Air (heating, cooling, humidification and re-heating treatment). • Supply conditioned and filtered air to different rooms, considering the room specific risk, containment functions and maintenance of the climatic and hygienic conditions. • Ensure a negative (gauge) pressure to rooms characterized by potential/permanent contamination. • Extract air from different rooms. • Filter air that presents the possibility of containing airborne contamination. • Release air to the environment. • Provide the capability of intervening on components for easy maintenance and high availability. To accomplish the above-mentioned functions, the HVAC System includes cold and hot water generators: Air Handling Units (AHUs), fans, valves, dumpers, grills, and air ducts, as well as the corresponding instrumentation and sensors.
Fig. 1. Schematic configuration of the IFMIF plant.
G. Pruneri et al. / Fusion Engineering and Design 103 (2016) 81–84 Table 1 IFMIF conventional facilities product breakdown structure. PBS number
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filtration stages according to the contamination level) through a stack.
PBS item
1
2
3
4
5
6
5
0 3
0 0 1
0 0 0
0 0 0
0 0 0
0 2
0 0
0 0
3 4
0 0
0 0
2.2. PIE Facility (Post Irradiation Experimental Facility) Conventional Facilities Plant Services Heating Ventilation and Air Conditioning (HVAC) System Nuclear HVAC PIE (Post Irradiation Examination Facility) Nuclear HVAC Industrial HVAC Heat/cold Source System
The PIE Nuclear HVAC System serves all of the areas that present potential or permanent levels of activation inside the PIE Facility, areas that are potentially contaminated by tritium, hot cells operating in the air, glove boxes, and inert gas glove boxes during the maintenance period (when they are operating in air). The Nuclear HVAC system for the PIE Facility is independent from the general HVAC System. The Nuclear HVAC of the IFMIF plant is shown in Fig. 2 on the right side.
According to the materials handled in the plant (liquid metal, such as lithium, that can react with air and humidity in the loop area, if in contact), some rooms will be kept under an inert gas atmosphere (argon) during operation. The supply and control of the purity of the noble gas environment is controlled by a dedicated Argon treatment and distribution system interfaced with the HVAC system. The Product Breakdown Structure (PBS) proposed for the plant is summarized in Table 1 and described below.
The Industrial HVAC system serves the areas that are free from any permanent contamination or which do not present any contamination hazard, for example, data storage rooms, server rooms, and data elaboration rooms; the intake air is filtered before it is distributed to the different areas, and the extracted air is directly released to the environment.
2.1. Nuclear HVAC
2.4. Heat source system
Nuclear HVAC systems serve areas that present potential or permanent levels of activation, areas that are potentially contaminated by tritium, hot cells operating in the air, glove boxes operating in the air, and inert gas hot cells during the maintenance period (when they are operated in air). The intake air is filtered before it is distributed to different areas. The extracted air is filtered and monitored before it is exhausted to the environment (different
Heated and chilled water generators condition and supply water for the heating, cooling, and re-heating coils of the AHUs (Table 2). The Main Building is a building that is four stories high and has the dimensions of approximately 137 m long, 111 m wide, and 40.5 m high (27 m high above the ground level); a bird’s eye view of the Main Building is shown in Fig. 3, where the PIE Building appears on the right side of the figure.
2.3. Industrial HVAC system
Fig. 2. IFMIF plant site layout.
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Table 2 Thermal capacity of the air handling units. HVAC system
AHU air volume (m3 h−1 )
AHU heating capacity (kW)
AHU cooling capacity + Cool/Humid (kW)
Nuclear HVAC Industrial HVAC
55,5510 83,850
6920 920
3210 + 1210 = 4420 1110
Fig. 4. Confinement configuration considered for the IFMIF plant.
Fig. 3. Artistic bird’s eye view of the IFMIF and HVAC rooms.
The construction and operation of the IFMIF will be subjected to the regulations of the country in which it will be sited. While it is not possible to anticipate what the requirements of the regulatory authorities will be, the IFMIF project has proposed criteria against which its safety performance could be quantitatively assessed. When possible, these criteria were based on the international guidelines set by the IAEA or the International Commissioning of Radiological Protection (ICRP); such guidelines are the basis of the national regulations in many countries for normal and accidental conditions. Zoning for personnel access was established on the basis of the radiation load. Each area of the IFMIF was categorized according to the concentration of airborne radioactive material, pressure gradients, and room atmosphere or fire protection, which are controlled through HVAC system by means of nuclear grade HVAC for areas where airborne contamination could exceed 1 DAC defining DAC as 20 mSv/(2000 h) × 1.2 m3 h−1 × DPUI (Dose per Unit Intake), and the industrial grade HVAC is used in non-radiological normal zones. Other classification references can be found in [3]. The main criteria of hazards released under normal operation conditions are the minimization of discharges from the plant. A confinement philosophy is assumed; therefore, independent barriers (passive confinement) are required to achieve high reliability to prevent releases that are complemented, when needed, by dynamic containment systems consisting of a specific ventilation system. The adopted criteria for the surface contamination of an area and the design and operation of ventilation systems mainly follow the ISO 17873 standards [3]. According to the ‘defense in depth principle’, the functionality of at least one barrier under all circumstances should be maintained (see Fig. 4). Thus, several containment systems are distinguished. Structures, systems and components are each assigned a particular SIC (Safety Important Components) classification that is based on the consequences of the failure of each component. The top-level criteria for the identification are: • Criteria A: their failure can directly initiate an accident, leading to significant risk of exposure or contamination.
• Criteria B: their operation is required to limit the consequences of an incident or accident that would lead to a significant risk of exposure or contamination. • Criteria C: their operation is required to ensure functioning SIC components. Two classes of SIC (SIC 1 and SIC 2) are defined to graduate the SIC components derived from the application of criteria A, B and C. Components and systems that are not SIC (either SIC 1 or SIC 2) can be identified as being safety relevant (SR) if they have some relevance to nuclear safety, such as components/systems, will not be credited in the safety analysis. The engineering process has continued in parallel with RAMI (Reliability, Availability, Maintainability and Inspectability) for all of the Conventional facility systems [2]. The results of RAMI analysis indicated 98% reliability availability; particularly for Nuclear HVAC, the RAMI analysis results substantially contributed to the optimization of the configuration of the system and will help to implement the engineering solutions for the next engineering phase, which is devoted to the future construction of the IFMIF. Acknowledgements This paper was prepared within the framework of the BA agreement between JAEA and EURATOM. Most of the information contained was derived from the contribution of Project Team (the Authors of this paper belong to the Project Team) and all of the institutions and Universities belonging to the International Fusion Community of IFMIF/EVEDA Project. The opinions and views expressed herein (outside of the technical contents) are purely those of the authors. References [1] J. Knaster, et al., The accomplishment of the engineering design activities of IFMIF/EVEDA: the European–Japanese project towards a Li(d,xn) fusion relevant neutron source, Nucl. Fusion 55 (2015) 086003 (30pp). [2] J.M. Arroyo, et al., RAMI Methodology and Activities for IFMIF Engineering Design, IPAC, San Sebastian, 2011. [3] International standard ISO 17873, Nuclear facilities – Criteria for the design and operation of ventilation system for nuclear installation other than nuclear reactor.
