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AbstractThe ITER Diagnostic Division is responsible for designing and procuring the First Wall Blankets that are mounted on the vacuum vessel port plugs at both the upper and equatorial levels. This paper will discuss the effects of the diagnostic aperture shape and configuration on the coolant circuit design. The Diagnostic First Wall (DFW) design is driven in large part by the need to conform the coolant arrangement to a wide variety of diagnostic apertures combined with the more severe heating conditions at the surface facing the plasma, the First Wall (FW). At the FW, a radiant heat flux of 35W/cm2combines with approximate peak volumetric heating rates of 8W/cm3(equatorial ports) and 5W/cm3(upper ports). Here at the FW, a fast thermal response is desirable and leads to a thin element between the heat flux and coolant. This requirement conflicts with the desire to have a thicker FW element to accommodate surface erosion and other off-normal plasma events.

AbstractThe port-based plasma diagnostic infrastructure on ITER is described, including the port plugs, the interspace support structure and port cell structure. These systems are modular in nature with standardized dimensions. The design of the equatorial and upper port plugs and their modules is discussed, as well as the dominant loading mechanisms. The port infrastructure design has now matured to the point that port plugs are now being populated with multiple diagnostics supplied by a number of ITER partners - two port plug examples are given.

AbstractA feasibility study for a fast-ion-loss detector in ITER has been carried out. Taking into account the basic requirements for measuring magnetohydrodynamic (MHD)-induced fast-ion (fusion-born alpha particles and ions from external heating systems) losses and the harsh environments expected in ITER plasmas, a solution based on a reciprocating probe installed in an equatorial port is suggested. In agreement with previous studies, Monte Carlo simulations of alpha-particle load on the first wall in MHD quiescent plasmas indicate that the main losses will be concentrated below the midplane, in the region of blanket module (BM) 15 to BM 18. Orbit tracing and thermal analysis, including plasma photonic and particle fluxes together with nuclear heating, have been performed to estimate the most suitable measurement timing and position of the reciprocating probe, enabling the detection of escaping alpha particles with pitch angles from ˜0 to 85 deg. This large velocity space ensures the detection of escaping alpha particles on both passing and trapped orbits, allowing the study of the interaction between alpha particles and a rich variety of MHD instabilities.

AbstractThis paper explains the present status of the ITER electron cyclotron emission (ECE) diagnostic and gives an outlook on the upcoming technical and design activity. The open questions of calibration and stability of ECE systems, as well as proposals for the calibration, the design of the front end, and the transmission line are reviewed. The possible role of ECE in the neoclassical tearing mode detection and stabilization by electron cyclotron heating is also discussed. Because integration of the ITER ECE diagnostic within the tokamak requires proper definition of interfaces with many different components located both in-vessel and ex-vessel, a special attention is paid to address the associated issues.

A preliminary thermo-hydraulic analysis was performed on the ITER diagnostic upper port plug. Relevant thermal and hydraulic parameters, such as coolant pressure drop, maximum structure temperature and bake-out time, were calculated for normal operation and baking. The upper port plug considered is based on the preliminary generic structure design of Princeton Plasma Physics Laboratory and the Blanket Shield Module (BSM) developed in Europe. The diagnostic shield modules are modeled so that the Korean diagnostic procurement package, which includes Vacuum Ultra-Violet (VUV) spectrometer and neutron activation system, can be integrated. The analysis provides design inputs to optimize flow in the cooling channels of the plug. The conjugated heat transfer analysis for the port plug confirms that it is important to secure accurate nuclear heat and accurate electro-magnetic (EM) force for the design of the joining flange between the BSM and the main body. Thermal analysis shows that it will take ten hours for the port plug to reach the bake-out temperature (240°C), if the window plate is heated additionally from the rear side.

A series of experiments are described which are aimed at quantifying the relative contribution of divertor leakage and radial ion transport on neutral pressures surrounding the core plasma. Evidence is presented implying that cross-field transport competes with, or dominates, parallel transport in such a way that plasma exists far out in the scrape-off layer (SOL) in the shadow of limiters and recycles on main chamber surfaces. The transition from L- to H-mode core confinement does not affect the far SOL characteristics nor the scaling of pressures around the plasma. Variations in magnetic equilibrium are used to vary the divertor pressures independent of the core plasma. Based on the analysis of such experiments using a simple neutral flow model we estimate that neutrals escaping from leaks in the lower (closed) divertor during lower x-point operation contribute a smaller fraction (~10-30%) of the midplane pressure than main chamber recycling. The inferred leakage is much larger from the upper (open) divertor during upper x-point operation. Most neutrals escaping from either divertor do not directly travel to the midplane. Instead, they are redirected, most likely by some combination of ionization and/or collisions (elastic, charge exchange).

A series of experiments are described which are aimed at quantifying the relative contribution of divertor leakage and radial ion transport on neutral pressures surrounding the core plasma. Evidence is presented implying that cross-field transport competes with, or dominates, parallel transport in such a way that plasma exists far out in the scrape-off layer (SOL) in the shadow of limiters and recycles on main chamber surfaces. The transition from L- to H-mode core confinement does not affect the far SOL characteristics nor the scaling of pressures around the plasma. Variations in magnetic equilibrium are used to vary the divertor pressures independent of the core plasma. Based on the analysis of such experiments using a simple neutral flow model we estimate that neutrals escaping from leaks in the lower (closed) divertor during lower x-point operation contribute a smaller fraction (~10-30%) of the midplane pressure than main chamber recycling. The inferred leakage is much larger from the upper (open) divertor during upper x-point operation. Most neutrals escaping from either divertor do not directly travel to the midplane. Instead, they are redirected, most likely by some combination of ionization and/or collisions (elastic, charge exchange).

Complementary DNA (cDNA) was prepared with RNA-dependent DNA polymerase from human globin messenger RNA (mRNA). Annealing and translation experimenta with total mRNA from circulating cells from a patient with heterozygous beta/heterozygous beta-delta-o thalassemia (beta-o/delta beta-o-thalassemia) demonstrated no detectable mRNA for beta-globin. cDNA enriched in sequences homologous to beta-globin mRNA was prepared by hydroxylapatite fractionation of hybrids formed between beta-o/delta beta-o-thalassemic mRNA and cDNA made from mRNA from a patient with alpha-thalassemia (hemoglobin H disease). The rate of annealing of this beta-enriched cDNA to normal human nuclear DNA was that of a sequence present as only a single copy per haploid genome. The beta-enriched cDNA annealed to the beta-o-delta beta-o-thalassemia total DNA with approximately the same kinetics as to normal DNA, indicating that no total gene deletion of beta-globin genes from the diploid genome has occurred, although the accuracy of the technique could not exclude with certainty a partial deletion or a deletion of a beta-globin gene from only one of the haploid genomes. This demonstrates that at least one of the beta-o- or the delta beta-o-thalassemia haploid genomes in this case contains a substantially intact beta-globin gene.