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• The shield block is one of the main in-vessel components for the ITER. • A PA for the manufacturing and testing of the SBs have been made between ITER organization and Korea domestic agency. • Key technologies of the SB are raw material, precise machining, non-destructive examination and hot helium leak testing. The SB is one of the main in-vessel components manufactured with SS316L(N)-IG to play a major role in neutron shielding, to support the FW panels and to supply the FW panel with cooling water. Cooling channels are located inside of the SB to remove the neutron heat deposition while keeping the structure temperature to acceptable levels. The water coolant is routed first through the plasma-facing first wall panel which is attached to the SB and then through the SB. A number of deep slits are introduced into the SB to disrupt eddy current loops and reduce the Electro-Magnetic (EM) loads on the support system and VV. Water headers are machined on the side of the module with 7–10 mm welded cover plates. A Procurement Arrangements (PAs) for the manufacturing and testing of the SBs have been signed with Korea (50 %) and China (50 %). As part of the PA in Korean Domestic Agency (KODA), Process Qualification (PQ) to ensure the manufacturing and testing ability of the SB was completed successfully through manufacture of a Full Scale Prototype (FSP) as an essential step before starting series production. This paper reports key technologies, such as machining, welding, NDE and hot helium leak testing, of manufacturing and testing for the ITER SB series production in Korea toward successful completion of the missions. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a statistical method for the calibration of a redundantly actuated hybrid serial-parallel robot IWR (Intersector Welding Robot). The robot under study will be used to carry out welding, machining, and remote handing for the assembly of vacuum vessel of International Thermonuclear Experimental Reactor (ITER). The robot has ten degrees of freedom (DOF), among which six DOF are contributed by the parallel mechanism and the rest are from the serial mechanism. In this paper, a kinematic error model which involves 54 unknown geometrical error parameters is developed for the proposed robot. Based on this error model, the mean values of the unknown parameters are statistically analyzed and estimated by means of Markov Chain Monte Carlo (MCMC) approach. The computer simulation is conducted by introducing random geometric errors and measurement poses which represent the corresponding real physical behaviors. The simulation results of the marginal posterior distributions of the estimated model parameters indicate that our method is reliable and robust. [Copyright &y& Elsevier]

Abstract: The fabrication of the ITER radial plates (RPs) is a demanding task, which includes machining and welding. It requires high accuracy with respect to its large size. There are two issues remained: (i) the productivity reduced by the large amount of machining and welding work; and (ii) the tight tolerance. A conventional machining center can be used only when segments and blocks are small. As a solution, this paper presents a method, which improves the final accuracy and increases the productivity. The method combines the powder metallurgy hot isostatic pressing (P/M HIP) technology and the mobile parallel kinematics machine system for fabricating the RPs. This paper first introduces the P/M HIP technology and describes the benefits of using the technology in the fabrication of the RPs, and then introduces the mobile machining/welding unit developed (ad hoc) and describes the possible manufacturing process to be used for the production of the radial plates. [Copyright &y& Elsevier]

Highlights • 10-channels U-shaped FW mock-up made by gun drilling, wire-cut EDM and hot bending. • Satisfactory hydro-tests and helium leak tests for 10-channels U-shaped FW mock-up. • Demonstration of fabrication feasibility of IN-LLCB TBM FW design. • Manufacturing sequence towards fabrication of larger scale FW mock-ups identified. Abstract The conceptual design of the Indian Lead Lithium Ceramic Breeder (LLCB) Test Blanket Module (TBM) First Wall (FW) presents a single U-shaped component made of IN-RAFM steel having 65 square channels of 20 mm × 20 mm running along the toroidal and radial direction. There are 13 circuits; each circuit consisting of 5 channels with inlet on the 1st channel of one side and the outlet on the 5th channel of other side. The conventional machining route with innovations in the existing technique was explored to develop the method to make channel mock-ups for FW application. This developed technique includes initial pre-machining and milling of higher thickness plates, making square channels by gun drilling followed by wire-cut EDM and final milling on the external surface and then hot bending into U-shape. Modified 9Cr-1Mo steel was the structural material used for this mock-up which has two flow circuits (each circuit of 5 channels). The other dimensions of this mock-up were chosen in such a way that functional requirements of full-sized FW would be fulfilled. During manufacturing, this mock-up was subjected to a series of inspection and non-destructive tests such as helium leak test and hydro-test at 150 bar pressure as a part of in-stage and final inspections. This paper describes the main activities carried out for the fabrication and factory acceptance tests of this U-shaped 10-channels TBM FW mock-up. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a novel mobile parallel robot, which is able to carry welding and machining processes from inside the international thermonuclear experimental reactor (ITER) vacuum vessel (VV). The kinematics design of the robot has been optimized for ITER access. To improve the accuracy of the parallel robot, the errors caused by the stiffness and manufacture process have to be compensated or limited to a minimum value. In this paper kinematics errors and stiffness modeling are given. The simulation results are presented. [Copyright &y& Elsevier]

Abstract: The present paper introduces a mobile parallel robot developed for International Thermonuclear Experimental Reactor (ITER). The task of the robot is to carry out welding and machining processes inside the ITER vacuum vessel. The kinematic design of the robot has been optimized for the ITER access. The kinematic analysis is given in the paper. A virtual prototype of the parallel robot is built. A dynamic behavior of the whole robot is studied by the multi-body system simulation (MBS). [Copyright &y& Elsevier]

• Key technology types involved in CFETR 1/8 V V sector model. • Methods and routes of key technologies of CFETR 1/8 V V sector model. • Current manufacturing progress of CFETR 1/8 V V sector model. This paper introduces key technologies and main advances in the development of the 1/8 vacuum vessel (VV) sector mockup of China fusion engineering test reactor (CFETR). The contour accuracy of each VV shell is controlled within ±2 mm through hot forming, solution treatment, and correction of each hyperboloid shell, and cold forming of the single-curved shell. The welding structure between the 1/8 sectors of CFETR VV on site is simulated by using the welding structure between two 1/16 VV sectors as a model. The narrow-gap TIG (NG-TIG) welding process is designed and explored in the sector welding of the 1/32 VV sector. Electron beam (EB) welding of the port stub is completed, and the weld quality meets the design requirement. The results of phased array ultrasonic testing (PAUT) technology reveal that the testing process meets RCC-MR technical requirements and solves the problems of full volume coverage (i.e., missed detection) and signal-to-noise ratio (i.e., misjudgment) of austenitic stainless steel welds. The automatic ray film arrangement trolley can achieve the automatic arrangement of the X-ray film between double shells when the VV is welded on-site. The measurement solution of three-dimensional complex space solves the problem of collimation positioning measurement during the welding, machining, and assembly of the 1/8 VV sector. The results of the study on the virtual assembly and reverse machining technology provide guidance for the actual assembly of the 1/8 VV sector. Finally, measurement and machining of the allowance are realized to solve the problem of numerical control machining of workpieces without a machining datum. [ABSTRACT FROM AUTHOR]

The assembly of ITER will involve the precise and accurate alignment of a large number of components and assemblies in areas where access will often be severely constrained and where process efficiency will be critical. One such area is the inside of the vacuum vessel where several thousand components shall be custom machined to provide the alignment references for in-vessel systems. The paper gives an overview of the process that will be employed; to survey the interfaces for approximately 3500 components then define and execute the customization process. [ABSTRACT FROM AUTHOR]

Last years have seen an increasing demand for large and precise parts following the growth of several sectors, such as conventional and nuclear power plants, shipbuilding industry, etc. The vacuum vessel of ITER is a paradigmatic example of one of those enormous systems that can only be processed in situ and from the inside. This paper reports on the development of a portable machine with serial kinematics to perform the machining, welding and post welding repair, finishing and NDT operations of the assembly procedure of the vacuum vessel of ITER. By applying the topology optimization method on the structure of the machine, a maximized stiffness–weight ratio and homogeneous stiffness figures in the different directions are achieved, thus reaching the goals of the machine with a minimum mass. Moreover, the machine avoids a constant monitoring by a human operator located in the nearby by being able to reference itself with respect to the existing geometry, inform about its position and orientation and automatically adapt its part programmes to perform its duty. The assessment of the machine performance is performed using FEM calculations. The serial kinematic portable machine developed in this manner is then compared with the existing solutions and its operational limits discussed. [ABSTRACT FROM AUTHOR]

Abstract: This paper will present a summary of the ShenGuangIII facility target chamber. During the machining the sphericity tolerances were addressed in forming process and numerical control vertical lathe for the individual plates. Procedure was developed for weld groove and welding of individual plates. The two hemispheric shells of the target chamber were welded in China Erzhong Group Co., Ltd. and sent to a temporary enclosure near the target bay for welding together. A drilling machine that can be accurately positioned on the sphere shell was used to bore the holes for the ports. After construction, the target chamber was lifted and placed on the support pedestal. The adjustment system and the precision surveyors with laser trackers were used to accurately position the target chamber on the pedestal support. The helium spray probe was used for the leak testing of the vacuum target chamber. Leak testing and repair of discovered leaks were performed to insure the vacuum integrity of the target chamber. A complete survey of the port flanges and custom contour machining of spacer plates were completed to insure that the devices attached to these port flanges meet the alignment requirement. The target shooting experiment of the sixth bundles of ShenGuangIII facility has shown that the target chamber satisfied the stability and precision criteria. [Copyright &y& Elsevier]

Abstract: For the benefit of the bidders for the Call-for-Tender for the 7 sectors of the ITER Vacuum Vessel, launched in early 2010, a large amount of relevant technical information was included to ensure a rapid start to successful manufacture programme, without the need for a full-scale prototype, which would cause an unacceptable delay to the ITER schedule. The methodology of the logical structures of the specification and the additional planned mock-ups are described and the results from nearly a decade of R&D and manufacturing studies carried out inside the EU under the auspices of EFDA and F4E are also summarised. The work covers the evolution of novel manufacturing schemes and technologies, including a modular special local machining centre for making holes in the shell of the vessel with weld preparation included. New results from the combined studies by three parties, and using a round-robin trial system on the UT inspection of single-sided welds, including the successful control of the root side are described. A full-scale, partial prototype has demonstrated the successful construction segments using jigs to control the distortion from conventional welding, from the inner shell to the outer shell, and then the joining of the segments to form a part sector. The paper also summarises the results from the prototype segment, manufactured without jigs and using only EB welds. In order to be able to achieve the required as-welded tight tolerances, two specialised computational techniques have been developed, using SYSWELD and ANSYS codes and calibrated with the mock-ups in order to efficiently predict welding distortions. Based on this successful practical and theoretical work, computer models of the complete poloidal segments or sectors, including jigs, were can now generated and used to investigate many welding sequences in order to optimise the construction and achieve all the tolerances. [Copyright &y& Elsevier]

Abstract: The assembly of ITER vacuum vessel (VV) is still a very big challenge as the process can only be done from inside the VV. The welding of the VV assembly is carried out using the dedicated robotic systems. The main functions of the robots are: (i) measuring the actual space between every two sectors, (ii) positioning of the 150kg splice plates between the sector shells, (iii) welding the splice plates to the sector shells, (iv) NDT of the welds, (v) repairing, including machining of the welds, (vi) He-leak tests of the welds, and (vii) the non-planned functions that may turn out. This paper presents a reasonable method to assemble the ITER VV. In this article, one parallel mobile robot, running on the track rail fixed on the wall inside the VV, is designed and tested. The assembling process, carried out by the mobile robot together with the welding robot, is presented. [Copyright &y& Elsevier]

Abstract: The paper presents an overview of the design, finite element (FE) analysis results, tests, and assembly strategy of the bolted connection between the coils of neighboring W7-X modules. The design is based on an accurately machined bridge and allows the accommodation of expected misalignments of the coil positions up to ±23mm and 1°. The joint is capable to cope with forces up to 1.3MN and moments up to 0.2MNm. Loads are transmitted by a combination of form lock provided by tapered coil block shoulders, and by friction on the bottom of the blocks. Special friction-enhancing foils are inserted between the bridge bottom surfaces and coil blocks to ensure a friction factor above 0.5. Non-linear FE analyses with elastic–plastic material models show that local plastification and even slippage in spite of the initial high friction are unavoidable but stay within an acceptable margin. In parallel, machining and assembly tests have been carried out to check and simplify the design further, and to develop the manufacturing strategy. [Copyright &y& Elsevier]

Abstract: This paper presents a special robot, able to carry out welding and machining processes from inside the ITER vacuum vessel (VV), consisting of a five degree-of-freedom parallel mechanism, mounted on a carriage driven by two electric motors on a rack. The kinematic design of the robot has been optimised for ITER access and a hydraulically actuated pre-prototype built. A hybrid controller is designed for the robot, including position, speed and pressure feedback loops to achieve high accuracy and high dynamic performances. Finally, the experimental tests are given and discussed. [Copyright &y& Elsevier]

This paper presents a new parallel robot Penta-WH, which has five degrees of freedom driven by hydraulic cylinders. The manipulator has a large, singularity-free workspace and high stiffness and it acts as a transport device for welding, machining and inspection end-effectors inside the ITER vacuum vessel. The presented kinematic structure of a parallel robot is particularly suitable for the ITER environment. Analysis of the machining process for ITER, such as the machining methods and forces are given, and the kinematic analyses, such as workspace and force capacity are discussed. [Copyright &y& Elsevier]

• The HRP provides a robust solution for the armor to heat sink joint, in terms of resistance to the HHF testing, • The tight geometrical tolerances constitute one of the main challenges for the IVT manufacturing. The good results obtained on the ANN Prototype can be further improved in order to meet new more stringent requirements and avoid the final machining of W plasma surfaces, • The "self-castellation" appearance previously observed on small scale mock-ups are confirmed on the full scale PFUs at a similar rate. These self-castellations, which appeared during the testing at 20 MW/m2, do not affect the monoblocks heat removal capability, but could have a detrimental impact on the monoblocks lifetime due to the creation of leading edges exposed to the direct particles flux in the strike point region, • The W manufacturing route and surface treatment are confirmed to have a significant influence on the self-castellations formation. Some refinement of the specifications to W Suppliers and IVT manufacturers are necessary in view of the IVT Series manufacturing. The Ansaldo Nucleare (ANN) Prototype manufacturing is under completion. The stainless steel support structure was manufactured by Walter Tosto (Italy) and the Plasma Facing Units (PFUs) were manufactured by ENEA (Italy) by diffusion bonding between the CuCrZr pipe and the W monoblocks equipped with a pure Cu compliance layer (Hot Radial Pressing, HRP). This paper presents some of the learnings of the Inner Vertical Target (IVT) Prototype manufacturing and provides the main results of the dimensional control tests. The outcomes of the PFUs High Heat Flux (HHF) testing performed in the ITER Divertor Test Facility (IDTF) in Efremov institute, Saint Petersburg (Russia) are presented as well. [ABSTRACT FROM AUTHOR]