IFMIF: Overview of the Validation Activities and of the Engineering Design Activities

Transcription

1 1 FTP/P1-35 IFMIF: Overview of the Validation Activities and of the Engineering Design Activities J. Knaster 1, H. Matsumoto 1, R. Heidinger 2, M. Sugimoto 3, A. Ibarra 4, A. Mosnier 2, F. Arbeiter 5, P. Favuzza 6, G. Micciche 6, V. Heinzel 5, F.S. Nitti 2, P. Cara 2, S. Chel 7, A. Facco 8, V. Massaut 9, N. Baluc 10, J. Theile 10 1 IFMIF/EVEDA Project Team, Rokkasho, Japan, 2 F4E, Garching, Germany, 3 JAEA, Rokkasho, Japan, 4 CIEMAT, Madrid, Spain, 5 KIT, Karlsruhe, Germany, 6 ENEA, Brasimone, Italy, 7 CEA, Saclay, France, 8 INFN, Legnaro, Italy, 9 SCK-CEN, Mol, Belgium, 10 CRPP Lausanne, Switzerland contact of main author: roland.heidinger@ifmif.org Abstract. The Engineering Validation and Engineering Design Activities for the International Fusion Materials Irradiation Facility (IFMIF) are entering into the conclusive stages. By July 2013, the engineering design of IFMIF will be completed by delivering an Intermediate IFMIF Engineering Design Report (IIEDR) supported by experimental results from the majority of the validation activities. A major role is attributed to the Accelerator Prototype (LIPAc) validation activities for which installation of sub-subsystems at the Rokkasho BA Site will start in early 2013 and for which, after the testing of the sub-systems, the installation and commissioning programme will extend till June Introduction The International Fusion Materials Irradiation Facility (IFMIF) is projected to provide an accelerator-based, D-Li neutron source to produce high energy neutrons at sufficient intensity and irradiation volume to simulate as closely as possible the first wall neutron spectrum of future nuclear fusion reactors such as DEMO and Power Plants [1]. The International Fusion Materials Irradiation Facility Engineering Validation and Engineering Design Activities (IFMIF/EVEDA), which started in 2007 under the framework of the Broader Approach (BA) Agreement between Japan and EURATOM, are entering into the conclusive stages [2,3]. By July 2013, the engineering design of IFMIF will be completed by delivering an Intermediate IFMIF Engineering Design Report (IIEDR) supported by experimental results from the majority of the validation activities [4,5]. An overview of the engineering design is reported here together with the outcome of the validation activities already achieved and still expected. Particular emphasis is given to the Accelerator Prototype (LIPAc) validation activities for which installation of sub-subsystems at the Rokkasho BA Site will start in early 2013 and for which after the testing of the subsystems, the installation and commissioning programme will extend till June Engineering Design of IFMIF The Engineering Design Activities in IFMIF/EVEDA are progressing in three specific stages (Facility/System identification and design requirements, Subsystem definition, Design Integration) towards issuing the Intermediate IFMIF Engineering Design Report (IIEDR) by June 2013 that describes a comprehensive and fully integrated engineering design of the

2 2 FTP/P1-35 IFMIF plant for a generic site. Since the Engineering Validation Activities will continue until June 2017 for the Accelerator Prototype Validation, it is expected that the results from the validation activities will give also feedback to future steps of the IFMIF design activities. Thus the objective of the IIEDR is not to supply a detailed engineering design but to provide the basis for configuring and deciding on the next step design activities in an IFMIF/CODA phase (Commissioning, Operation and Decommissioning Activities). The IIEDR addresses reliability, availability, and maintainability analysis [6], extends the preliminary safety assessment [7] by performing the preliminary safety analysis of the Facility and will provide a consolidated cost estimation. Currently the second stage is under conclusion. As a result of the initial Engineering Design Activities, the early mission statements [8] have been revisited, and the top plant-level requirements derived [9] taking account of users specifications [10]. The IFMIF plant configuration has been established with the definition of five IFMIF facilities (see below) and of their interfaces. A plant layout has been set up accordingly (cf. Fig.1) Fig.1 IFMIF plant layout in architectural (above) and isometric view (below). Test Facilities and Li Target Facility are merged and Conventional Facilities not shown. Further to the documentation of the requirements, specifications and description at the IFMIF plant level in the IIEDR, this information has been broken down to the facility-/system-level (cf. Fig.2) The design description at facility-/system-level is being documented in Design Description Documents (DDD) developing over the specific 3 stages through the editing and reviewing in an increasing level of detail covering the definition and modelling of functions, component descriptions, digital mock-ups, design analysis, preliminary safety analysis and cost estimates at facility and system level.

3 3 FTP/P1-35 Fig. 2 Plant configuration diagram with facilities broken down to systems [9] The details of the design of the 5 facilities which form the first level of the Work Breakdown Structure of the IFMIF plant [4] are still evolving, but can be summarised as follows, while in the references more detailed descriptions of the systems and subsystems can be found: (1) the Accelerator Facility that generates and directs a 2x125 ma current of 40 MeV deuterons (D + ) in continuous wave operation to the liquid lithium target through two separate Linac systems [5,11]; (2) the Lithium Target Facility in which the intense neutron flux is generated by a stripping reaction of the deuterons with lithium nuclei [12] in a Target System that can fully stop the deuteron beams and handle the thermal load of 10 MW[13,14]; (3) the Test Facilities composed of the Test Modules which are specially designed for materials and systems testing in accordance to the IFMIF mission and the users specification and which are installed in the High/Medium/Low Flux areas of the Test Cell [15,16]; (4) the Post Irradiation Examination (PIE) facilities for mechanical and physical property measurements and metallurgical materials characterisation with the capability of handling tritium-contaminated specimens [17,18,19]; (5) the Conventional Facilities that provide the overall infrastructure while considering operational safety and reliability of the plant as an integral entity [9]. 3. Experimental Validation Activities In order to produce the experimental backing of the IFMIF design during the EVEDA phase, 3 major prototypes have been designed and are being manufactured, commissioned and operated: o an Accelerator Prototype (LIPAc) at Rokkasho, fully representative of the IFMIF low energy (9 MeV) accelerator (125 ma of D + beam in continuous wave) to be completed in June 2017 [20,21];

4 4 FTP/P1-35 o a Lithium Test Loop (ELTL) at Oarai, integrating all elements of the IFMIF lithium target facility, already commissioned in February 2011 [22,23] complemented by corrosion experiments performed at the LIFUS6 lithium loop at Brasimone [24]; o a High Flux Test Module (different designs) [25,26] and its internals, of which critical components will be irradiated in a fission reactor [27] and selected prototypes tested in the helium loop HELOKA-LP [28], complemented by a Creep Fatigue Test Module [29] manufactured and tested in full scale at Villigen. While this overview has to leave to the above cited papers the description of design and experimental details, also of the overall activities, the focus is given here to the outcome of the validation activities already achieved and still expected The Accelerator Prototype Validation activities The setting-up of the LIPAc facility in Rokkasho, for which the first accelerator sub-systems provided by the European Home Team will arrive in early 2013, requires a well-coordinated integration and commissioning programme. This is due to the distributed nature of the deliveries sice the building, the main auxiliaries, the central control system and the couplers for the RF Quadrupoles are provided by the Japanese Home Team whereas all other systems and sub-systems are provided by the European Home Team. As an essential element of this programme, specific central databases, management systems and procedures have been implemented such as a documentation management system, an interface management system, assembly procedures and a configuration management of the 3D digital mock-up of the facility (cf. Fig. 3) [30]. Fig. 3 Three dimensional (3D) digital mock-up of the LIPAc facility as planned for set-up in Rokkasho The Injector The Injector developed for producing a deuteron beam of 140 ma at 100 kev was assembled at Saclay in order to test its components before their shipment to Rokkasho, scheduled at the beginning of After first having extracted H+ beams of pulsed 150 ma at 100 kv and

5 5 FTP/P1-35 continuous beams of 100 ma at 75 kv, explorative tests with D+ beams followed for a short period to keep the activation at tolerable levels [31]. It turned out that the continuous operation at 100 kv was limited by HV discharges in the extraction system, so a new 5 electrode system was installed and optimization of the Injector performance is to start soon by adjusting the operation parameters such as the ion source plasma, krypton pressure, and solenoid setting The Radio Frequency Quadrupole (RFQ) The Radio Frequency Quadrupole (RFQ) is formed by normal-conducting 175 MHz resonator, bunching and accelerating a 125 ma CW beam to 5 MeV. Its development at Legnaro has reached such a level of maturity in manufacturing and brazing that the first of 3 supermodules will be completed by October 2012 for subsequent high power tests [32]. The RF power (200kW) is injected into the cavity by means of RF Power Couplers which have been tested with a high-q load circuit at JAEA-Tokai [33]. The RF tuning methodology for the required large set of tuners has been successfully developed using an aluminium mock-up of this long RFQ geometry (9.81 m) The Superconducting Radio Frequency LINAC (SRF Linac) In the Superconducting Radio Frequency Linac (SRF Linac) the beam energy is brought up to 9 MeV by using superconducting 175 MHz half-wave resonators and focussing solenoids. Two prototypical resonant cavities have been fabricated. The original design of the tuner relied on a capacitive plunger with a large membrane to allow an elastic deformation of ±1 mm. Tests at cryogenic temperature showed excessive RF losses as well as a quench at low field shedding doubt on the plunger concept. As a consequence, a new design based on a conventional compression tuner principle is under development [34] which implies a lengthening of the cryomodule to ease the integration of the mechanical tuning mechanism The High Energy Beam Transport (HEBT) line and the Beam Dump The beam leaving the SRF Linac is characterized along the HEBT line and transported into the conical beam dump, designed to stop the MW deuteron beam [35]. The line includes eight quadrupoles which provide the necessary beam focussing and a dipole that bends the beam to reduce the radiation from the beam dump received by the SRF Linac. Thermo-mechanical studies of the beam dump showed a high robustness to beam errors, CW and pulsed mode operation, buckling, and high velocity coolant flow effects. The HEBT and the beam dump are in the final stage of detailed design, and cartridge prototypes have been built. Hydraulic test of a full scale cartridge is on-going. Integration and test of the complete beam dump is planned at mid Diagnostics A full set of non-interceptive diagnostics [36] to monitor and to characterize the beam all along the accelerator has been developed: current monitors of various types (ACCT, DCCT, FCT), 20 beam position monitors (8 of them at cryogenic temperature), beam profile monitors (based on ionization and fluorescence of the residual gas), about 40 beam loss monitors (ion chamber LHC type), micro-loss monitors (based on CVD diamond operating at cryogenic

6 6 FTP/P1-35 temperature) and a bunch length monitor (residual gas). For short chopped beam pulses, SEM grids and slits will be used for emittance and energy spread measurement Lithium Target Facility Validation Activities A lithium test loop, physically equivalent to the loop in the IFMIF Plant, with a free surface of reduced flow width, has been built at Oarai. The loop was successfully commissioned in February 2011 with an integral concept target assembly manufactured in stainless steel. A stable Li flow at a velocity of 5 m/s was achieved in the target assembly with an Ar gas pressure of 0.12 MPa [22]. In autumn 2012 the loop will have fully recovered from the damage suffered at the time of East Japan Great earthquake [23]. During this restoration work, the first test operation was conducted to gain critical information about the geometrical stability of the lithium flow and the performance of the flow guiding structure up to 20 m/s flow speed. Further work to implement impurity traps and monitors is also planned in late Dedicated corrosion tests for austenic and ferritic-martensitic steels were planned with the existing LIFUS3 loop at Brasimone but could not be executed because of complexity of the systems hydraulics. Therefore the LIFUS6 loop [24] was built with a simplified configuration from the hydraulic point of view and with the cold (oxygen, carbon) trap continuously operated and the hot (nitrogen) trap operated in batch. Its start-up is expected for Test Facility Validation Activities The design and validation of the test facilities are predominantly conducted in the European Home Team. Design work of the test facilities is being accompanied by prototyping of the High Flux Test Module (HFTM) and internal rigs for post-irradiation examination of miniature-size specimens of fusion reactor materials [25]. Positive results on the availability of the Small Specimen Testing Techniques for fracture toughness, crack growth rate and creep fatigue behaviour have been recently contributed by the Japanese Home Team [37]. It is also making progress on the design and R&D of an alternative proposal of HFTM, potentially enabling irradiation under very high temperatures, adequate for irradiation testing of SiC [26]. The performance under irradiation of both concepts will be tested using the Belgian material test reactor BR2 in Mol [27]. High-Flux-Test modules have been manufactured and a helium loop (HELOKA-LP) has been installed at Karlsruhe in a scale 1:1 for thermohydraulic testing at IFMIF relevant conditions [28]. A Creep Fatigue Test Module is being tested as a representative Medium Flux Test module in full scale during which long-term tests are being run under the pressure condition prevailing in the Target and Test Cell. Acknowledgement This paper has been prepared within the framework of the BA Agreement between Japan and EURATOM. The authors gratefully acknowledge the contributions from the Project Team and from each institution and university forming the IFMIF/EVEDA Integrated Project Team (IFMIF IPT). The views and opinions expressed herein do not necessarily reflect those of Fusion for Energy, JAEA, and of the IFMIF IPT.

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