Engineering requirements due to the ESP/ESPN regulation apply at the port plug for ITER diagnostic system

Giacomin, T.,Delhom, D.,Drevon, J.-M.,Guirao, J.,Iglesias, S.,Jourdan, T.,Loesser, D.,Maquet, P.,Ordieres, J.,Pak, S.,Proust, M.,Smith, M.,Udintsev, V.S.,Vacas, C.,Walsh, M.J.,Zhai, Y. Elsevier 2015 Fusion engineering and design Vol.98 No.-

<P><B>Abstract</B></P> <P>Due to this position close to the plasma, the port plug structure and the diagnostic first wall (DFW) contain water to allow cooling during operation and for heating during bake-out. To remove the heat coming from the plasma due to radiation and neutrons, the pressure inside these structures should be up to 44 bars. On the other hand, the dominant load expected to drive the design of these structures is of electromagnetic origin during the plasma disruption. Description of the loads acting on DFWs and generic port plug structures and the significance of the load due to the water pressure, with implications on the design and inspection, are discussed in this paper.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The ESP/ESPN regulation is applied to all equatorial and upper port-based diagnostic systems. </LI> <LI> The EPP and UPP structure provides a flexible platform for a variety of diagnostics. </LI> <LI> The EPP and UPP structure provide a support the diagnostic shielding module. </LI> </UL> </P>

Reflections on inflections

C. Saengow,A.J. Giacomin,P.H. Gilbert,C. Kolitawong 한국유변학회 2015 Korea-Australia rheology journal Vol.27 No.4

In plastics processing, the single most important rheological property is the steady shear viscosity curve: the logarithm of the steady shear viscosity versus the logarithm of the shear rate. This curve governs the volumetric flowrate through any straight channel flow, and thus governs the production rate of extruded plastics. If the shear rate is made dimensionless with a characteristic time for the fluid (called the Weissenberg number, Wi), then we can readily identify the end of the Newtonian plateau of a viscosity curve with the value Wi~1. Of far greater importance, however, is the slope at the point where the viscosity curve inflects, (n−1), where n is called the shear power-law index. This paper explores the physics of this point and related inflections, in the first and second normal stress coefficients. We also discuss the first and second inflection pairing times, lambda'_B and lambda''_B. First, we examine the generalized Newtonian fluid (Carreau model). Then, we analyze the more versatile model, the corotational Oldroyd 8-constant model, which reduces to many simpler models, for instance, the corotational Maxwell and Jeffreys models. We also include worked examples to illustrate the procedure for calculating inflection points and power-law coefficients for all three viscometric functions, eta, psi_1 and psi_2

Final design of the generic upper port plug structure for ITER diagnostic systems

Pak, S.,Feder, R.,Giacomin, T.,Guirao, J.,Iglesias, S.,Josseaume, F.,Kalish, M.,Loesser, D.,Maquet, P.,Ordieres, J.,Panizo, M.,Pitcher, S.,Portales, M.,Proust, M.,Ronden, D.,Serikov, A.,Suarez, A.,Tan North-Holland ; Elsevier Science Ltd 2016 Fusion engineering and design Vol.102 No.-

The generic upper port plug (GUPP) structure in ITER is a 6m long metal box which deploys diagnostic components into the vacuum vessel. This structure is commonly used for all the diagnostic upper ports. The final design of the GUPP structure, which has successfully passed the final design review in 2013, is described here. The diagnostic port plug is cantilevered to the vacuum vessel with a heavy payload at the front, so called the diagnostic first wall (DFW) and the diagnostic shield module (DSM). Most of electromagnetic (EM) load (~80%) occurs in DFW/DSM. Therefore, the mounting design to transfer the EM load from DFW/DSM to the GUPP structure is challenging, which should also comply with thermal expansion and tolerance for assembly and manufacturing. Another key design parameter to be considered is the gap between the port plug and the vacuum vessel port. The gap should be large enough to accommodate the remote handling of the heavy port plug (max. 25t), the structural deflection due to external loads and machine assembly tolerance. At the same time, the gap should be minimized to stop the neutron streaming according to the ALARA (as low as reasonably achievable) principle. With these design constraints, the GUPP structure should also provide space for diagnostic integration as much as possible. This requirement has led to the single wall structure having the gun-drilled water channels inside the structure. Furthermore, intensive efforts have been made on the manufacturing study including material selection, manufacturing codes and French regulation related to nuclear equipment and safety. All these main design and manufacturing aspects are discussed in this paper, including requirements, interfaces, loads and structural assessment and maintenance.

Engineering issues on the diagnostic port integration in ITER upper port 18

Pak, S.,Bertalot, L.,Cheon, M.S.,Giacomin, T.,Heemskerk, C.J.M.,Koning, J.F.,Lee, H.G.,Nemtcev, G.,Ronden, D.M.S.,Seon, C.R.,Udintsev, V.,Yukhnov, N.,Zvonkov, A. North-Holland ; Elsevier Science Ltd 2016 Fusion engineering and design Vol.109 No.1

The upper port #18 (UP18) in ITER hosts three diagnostic systems: the neutron activation system, the Vacuum Ultra-Violet spectrometer system, and the vertical neutron camera. These diagnostics are integrated into three infrastructures in the port: the upper port plug, interspace support structure and port cell support structure. The port integration in UP18 is at the preliminary design stage and the current design of the infrastructure as well as the diagnostic integration is described here. The engineering issues related to neutron shielding and maintenance are addressed and the design approach is suggested.

Converging shear rheometer

백형민,Adam W. Mix,A. Jeffrey Giacomin 한국유변학회 2014 Korea-Australia rheology journal Vol.26 No.2

For highly viscous fluids that slip in parallel sliding plate rheometers, we want to use a slightly convergingflow to suppress this wall slip. In this work, we first attack the steady shear flow of a highly viscousNewtonian fluid between two gently converging plates with no slip boundaries using the equationof motion in cylindrical coordinates, which yields no analytical solution. Then we treat the same problemusing the lubrication approximation in Cartesian coordinates to yield exact, explicit solutions for dimensionlessvelocity, pressure and shear stress. This work deepens our understanding of a drag flow througha gently converging slit of arbitrary convergence angle. We also employ the corotational Maxwell modelto explore the role of viscoelasticity in this converging shear flow. We then compare these analytical solutionsto finite element calculations for both Newtonian and corotational Maxwell cases. A worked examplefor determining the Newtonian viscosity using a converging shear rheometer is also included. Withthis work, we provide the framework for exploring other constitutive equations or other boundary conditionsin future work. Our results can also be used to design the linear bearings used for the parallel slidingplate rheometer (SPR). This work can also be used to evaluate the error in the shear stress that iscaused by bearing misalignment and specify the parallelism tolerance for the linear bearings incorporatedinto a SPR.

Power series for shear stress of polymeric liquid in large-amplitude oscillatory shear flow

Pongthep Poungthong,Chaimongkol Saengow,Alan Jeffrey Giacomin,Chanyut Kolitawong 한국유변학회 2018 Korea-Australia rheology journal Vol.30 No.3

Exact solutions for shear stress in a polymeric liquid subjected to large-amplitude oscillatory shear flow (LAOS) contain many Bessel functions. For the simplest of these, for instance, the corotational Maxwell fluid, in the closed form for its exact solution, Bessel functions appear 42 times, each of which is inside a summation. Approximate analytical solutions for shear stress in LAOS often take the form of the first few terms of a power series in the shear rate amplitude, and without any Bessel functions at all. There is thus practical interest in extending the Goddard integral expansion (GIE), to an arbitrary number of terms. In continuum theory, these truncated series are arrived at laboriously using the GIE. However, each term in the GIE requires much more work than its predecessor. For the corotational Maxwell fluid, for instance, the GIE for the shear stress has yet to be taken beyond the sixth power of the shear rate amplitude. In this paper, we begin with the exact solution for shear stress responses in corotational Maxwell fluids, and then perform an expansion by symbolic computation to confirm up to the sixth power, and to then continue the GIE. In this paper for example, we continue the GIE to the 40th power of the shear rate amplitude. We use Ewoldt grids to show our main result to be highly accurate. We also show the radius of convergence of the GIE to be infinite.

Converging shear rheometer

Baek, Hyung M.,Mix, Adam W.,Giacomin, A. Jeffrey 한국유변학회 2014 Korea-Australia rheology journal Vol.26 No.2

For highly viscous fluids that slip in parallel sliding plate rheometers, we want to use a slightly converging flow to suppress this wall slip. In this work, we first attack the steady shear flow of a highly viscous Newtonian fluid between two gently converging plates with no slip boundaries using the equation of motion in cylindrical coordinates, which yields no analytical solution. Then we treat the same problem using the lubrication approximation in Cartesian coordinates to yield exact, explicit solutions for dimensionless velocity, pressure and shear stress. This work deepens our understanding of a drag flow through a gently converging slit of arbitrary convergence angle. We also employ the corotational Maxwell model to explore the role of viscoelasticity in this converging shear flow. We then compare these analytical solutions to finite element calculations for both Newtonian and corotational Maxwell cases. A worked example for determining the Newtonian viscosity using a converging shear rheometer is also included. With this work, we provide the framework for exploring other constitutive equations or other boundary conditions in future work. Our results can also be used to design the linear bearings used for the parallel sliding plate rheometer (SPR). This work can also be used to evaluate the error in the shear stress that is caused by bearing misalignment and specify the parallelism tolerance for the linear bearings incorporated into a SPR.

Preliminary Design for Diagnostic Port Integration at ITER Upper Port #18

Pak, S.,An, Y. H.,Seon, C. S.,Choi, J. H.,Cheon, M. S.,Lee, H. G.,Udintsev, V.,Giacomin, T. Institute of Electrical and Electronics Engineers 2018 IEEE transactions on plasma science Vol. No.

<P>ITER has many ports to install various diagnostics which view and measure various plasma parameters. One of the ports, the upper port #18 (UP18) is designed to integrate three tenant diagnostic systems: vacuum ultraviolet spectrometer, neutron activation system, and upper vertical neutron camera. The key design drivers for the port integration are requirements on neutron shielding and maintenance. In this paper, we discuss the neutron shielding design made following the as low as reasonable achievable principle in order to reduce the shut-down dose rate in the interspace and port cell which are human-accessible areas. The design choice for radiation shielding of electronics in the port cell is also discussed. The port maintenance in ITER consists of remote handling operation for the port plug and manual (or assisted-manual) operation for the interspace and port cell areas. The compatibility with the ITER maintenance strategy is investigated for UP18 and the associated issues are addressed.</P>