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The Diagnostic Generic Equatorial Port Plug (GEPP) is designed to be common to all equatorial port-based diagnostic systems. It is designed to survive throughout the lifetime of ITER for 20 years, 30,000 discharges, and 3000 disruptions. The EPP structure dimensions (without Diagnostic First Walls and Diagnostic Shield Modules) are L2.9 × W1.9 × H2.4 m 3 . The length of the fully integrated EPP is 3174 mm. The weight of the EPP structure is about 15 t, whereas the total weight of the integrated EPP may be up to 45 t. The EPP structure provides a flexible platform for a variety of diagnostics. The Diagnostic Shield Module assemblies, or drawers, allow a modular approach with respect to diagnostic integration and maintenance. In the nuclear phase of ITER operations, they will be remotely inserted into the EPP structure in the Hot Cell Facility. The port plug structure must also contribute to the nuclear shielding, or plugging, of the port and further contain circulated water to allow cooling during operation and heating during bake-out. The Final Design of the GEPP has been successfully passed in late 2013 and is now heading toward manufacturing. The final design of the GEPP includes interfaces, manufacturing, R&D, operation and maintenance, load cases and analysis of failure modes. [ABSTRACT FROM AUTHOR]

At first a detailed fast shutter design was finalized for the ITER core charge exchange recombination spectroscopy (CXRS) diagnostic. The shutter has approximately 70 kg of mass and a length of 2.1 m. It operates in fractions of a second (0.7 s) protecting critical optical components against degradation and providing means of calibration for the optical system. The shutter structure is driven by a bidirectional frictionless helium actuator, with forces and axial strokes of 3.4 kN and 2 mm respectively. The shutter structure consists of: (a) two blades made of CuCrZr and stainless steel, calibration surfaces (currently Al 2 O 3 ) on the top and on the bottom a protective TZM (Mo–0.5Ti–0.08Zr) screens, (b) two arms interconnected that form one cooling circuit including the blades, (c) a bumper system to limit the arms movement, and (d) a support. A description of these components and their functions are given in this paper, followed by some issues, and their corresponding solutions or ongoing investigations, encountered during the design work. Detailed manufacturing drawings have been developed as the deliverable final product of this design stage, and are used in the prototyping phase which includes testing, numerical benchmarking, and validation of the shutter concept. [ABSTRACT FROM AUTHOR]

The ITER core charge exchange recombination spectroscopy diagnostics (cCXRS) occupies the vacuum vessel upper port #3 and includes, in its generic version, the following in-vessel components: an optical mirror system, a shutter, the diagnostic first wall and the neutron shielding block. The most vulnerable diagnostic mirror is obviously the first one (M1) directly observing the plasma. The M1 reference option is made of a single crystalline molybdenum (ScMo). The paper indicates major aspects influencing the first mirror design and identifies the most reasonable and reliable concept for cCXRS M1 at present. The applicability of the option presented is determined by many reasons, and especially, by the ITER generic upper port plug and its customization flexibility. The largest dimension of the mirror polished face is ∼300 mm. Such large ScMo workpieces are currently not available on the market. The mirror should be designed as an assembly of several ScMo pieces joined together. The M1 design is supported by multifield thermal, electromagnetic and structural analyses. The performed study confirms the feasibility of the proposed solutions. At the same time, the paper indicates numerous technological issues of the M1 unit to be solved in future. [ABSTRACT FROM AUTHOR]

Abstract: The Equatorial Visible/InfraRed Diagnostic is one of the key diagnostics of ITER, due to its crucial role for the machine protection, through the determination of plasma facing components temperatures (infrared range) and the first wall survey (visible range). Due to its location (close to the plasma) and its complexity (two types of wavelength must be transferred from the plasma to the detectors), the development of this diagnostic needs to address a lot of non-trivial issues. Significant technical advancements have been performed since a few years. This paper focuses on the recent progress made on the design and integration of the diagnostic. After a short description of the system, this paper shows the changes proposed for its integration in the port plugs where it is installed and the improvements brought to its design. It also presents the first results of a neutronic analysis which aims at optimizing the geometry of the dog leg mirrors forming a labyrinth for the neutrons in the port plug. [Copyright &y& Elsevier]

Abstract: For the optical system of the core CXRS port plug several designs were developed in the last years. A survey is given of the three most relevant designs. The first design is based on an off-axis ellipsoid mirror as main imaging component. This design has been the basis of opto-mechanical design as described in previous publications . This design is presented and assessed with regard to the optical properties, the sensitivity to first mirror degradation, the possibility to include a tube to allow replacement of the first mirror (as a possible mitigation of the first mirror degradation) and the manufacturability. Two alternatives are presented that alleviate the issues connected to the optical design. These alternatives may improve both lifetime and manufacturability of the core CXRS port plug. [Copyright &y& Elsevier]

Abstract: New optical configurations for the ITER core CXRS system offer the possibility of longer ducts between the first mirror and the plasma. This has led to a renewed optimization of the availability, using a simple model of the degradation of the first mirror that starts with the conditions of (a) the required measurement performance and (b) the geometry of the port plug. It is found that for a fully passive system the design should strive for the longest duct length possible. Given known data, this will result in a diagnostic lifetime still substantially shorter than ITER lifetime. When an option of cleaning the first mirror is introduced (assuming this is a feasible option) the optimum is less straightforward, because the lifetime of the second mirror then also becomes important. The optimum then depends on the ratio between the cleaning interval and the ITER lifetime. Options are presented for various sets of assumptions. Finally practical limitations of supporting subsystems (cleaning system, shutter, calibration system) may influence the final design. Examples of such limitations with their impact are presented. [Copyright &y& Elsevier]

Abstract: Most of ITER diagnostic systems are integrated in port plugs, which are water cooled stainless steel structures inserted into the vacuum vessel ports. The port plug must provide basic functions such as neutron and gamma shielding, supporting the first wall armour (BSM), closing the vacuum vessel ports, while supporting the diagnostic equipments. ITER diagnostic port plug must resist a severe environment like high temperature due to neutron interaction with the structures and high electromechanical loading during disruptions events. CEA has contributed to the design and integration tasks in the frame of the representative equatorial port plug EQ#01, in particular on the engineering, structural and thermal finite element analysis. These detailed analyses have highlighted some design issues which were worked out through different solutions. This paper contains a description of the engineering activities performed such as: [-] The static mechanical calculations of the top plate closure system under disruption load. [-] The static mechanical calculations of the BSM attachment to the port plug. These two first studies led to design changes proposals which significantly improved the behaviour of the structures but also showed that the safety margin with respect to design limits is quite low. [-] The design of a Diagnostic Shield Module (DSM) integrated inside the port plug and a proposition of attachment scheme, with respect to disruption loads. The manufacturing of the DSM has been taken into account, as well as diagnostic integration inside the structure and maintenance aspects. [-] The thermal assessment of the port plug under neutronic load during normal operation, with the optimization of the cooling system. The maximum temperature calculated in normal operation has been reduced from 900°C to less than 400°C in the front plate; and the cooling arrangement at the back of the port plug has been simplified without important temperature increase. [Copyright &y& Elsevier]

Abstract: Engineering analyses have been performed for the representative diagnostic upper port plug of ITER. Maintenance and integration design have been also carried out for the diagnostic components to be installed in the upper port plug. From the electromagnetic and structural analyses, it has come up an important problem to suppress the displacement of the upper port plug rather than to reduce the produced stress. Reducing the electro-magnetic (EM) force will help to decrease the severity of potential displacement. Maximum displacement of the port plug decreases with increase in the number of slits in a manner that the displacement would seem to be less than the design tolerance. A proposed low body roller and inner frame may enhance maintenance and integration. These studies and designs have established the design basis for the diagnostic upper port plug. [Copyright &y& Elsevier]