Fracture mechanics analysis approach to assess structural integrity of the first confinement boundaries in ITER Generic Upper Port Plug structure

Guirao, Julio,Iglesias, Silvia,Vacas, Christian,Udintsev, Victor,Pak, Sunil,Maquet, Philippe,Rodriguez, Eduardo,Roces, Jorge Elsevier 2015 Fusion engineering and design Vol.98 No.-

<P><B>Abstract</B></P> <P>This paper demonstrates structural integrity of the first confinement boundary in Generic Upper Port Plug structures against cracking during service. This constitutes part of the justification to demonstrate that the non-aggression to the confinement barrier requirement may be compatible with the absent of a specific in-service inspections (ISI) program in the trapezoidal section. Since the component will be subjected to 100% volumetric inspections it can be assumed that no defects below the threshold of applied Nondestructive Evaluation techniques will be present before its commissioning. Cracks during service would be associated to defects under Code acceptance limit. This limit can be reasonably taken as 2mm. Using elastic–plastic fracture mechanics an initial defect is postulated at the worst location in terms of probability and impact on the confinement boundary. Its evolution is simulated through finite element analysis and final dimension at the end of service is estimated. Applying the procedures in RCC-MR 2007 (App-16) the stability of the crack is assessed. As relative high safety margin was achieved, a complementary assessment postulating an initial defect of 6mm was also conducted. New margin calculated provides a more robust design.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A parametric submodel of the spot under study is developed. </LI> <LI> The associated macro has the capability to successively re-build the submodel implementing the crack with the geometry of the updated crack front as a function of the predicted increments of length in the apexes of the crack from the calculated stress intensity factor at the crack front. </LI> <LI> The analysis incorporates the crack behavior model to predict the evolution of the postulated defect under the application of the different transients. </LI> <LI> The analysis is based on the Elasto-Plastic Fracture Mechanics (EPFM) theory to account for the ductility of the materials (316LN type stainless steel). </LI> </UL> </P>

The choice of dynamic amplification factors for the ITER generic port plugs during disruptions

Vacas, Christian,Rodriguez, Eduardo,Guirao, Julio,Iglesias, Silvia,Udintsev, Victor,Pak, Sunil,Maquet, Philippe,Roces, Jorge,Casal, Natalia Elsevier 2015 Fusion engineering and design Vol.98 No.-

<P><B>Abstract</B></P> <P>The purpose of this paper is present an overview of the methodology followed to calculate the dynamic amplification factors applied to the electromagnetic loads acting in the ITER generic port plugs.</P> <P>The methodology used for combining an EM transient event with another kind of load is based in the treated of this dynamic EM event as a static load. As first stage a transient dynamic analysis was performed, at the most demanded electromagnetic event [2], to determine the dynamic response of the port plugs. In the same way, have been solved all the time steps of the dynamic event as static loads, it means that the inertial effect has been neglected. The response of each time-step at the dynamic solution has been compared with the same time-step solved as a static load. For this purpose some control points were positioned along the structure at the most representative locations. The key of these calculations is the understanding of the deformed modes affecting the port plug in order to obtain a reasonable dynamic amplification factors that permit the characterization of these loads in a realistic way and does not derive in a too conservative approach. Additionally, the fundamental frequencies and vibration modes of the generic port plug, requested for the characterization of the damping effects at the structure, were calculated in a complementary modal analysis performed for this aim.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Dynamic amplification factor is largely influenced by the DFWs geometry and for the type of bond between DFW and DSM. </LI> <LI> DAF were calculated by analyzing the deformed shape and not just looking at the absolute values of displacements. </LI> <LI> Detailed transient time history non-linear analysis of an MDUP II electro magnetic event has been carried out. </LI> <LI> Cuasi-constant damping ratio of 3% has been considered using a generalized proportional damping model. </LI> </UL> </P>

Supramolecular Zinc Phthalocyanine-Imidazolyl Perylenediimide Dyad and Triad: Synthesis, Complexation, and Photophysical Studies

Cé,spedes-Guirao, F. Javier,Ohkubo, Kei,Fukuzumi, Shunichi,Ferná,ndez-Lá,zaro, Fernando,Sastre-Santos, Á,ngela Wiley (John WileySons) 2011 Chemistry, an Asian journal Vol.6 No.11

<P>Two new supramolecular architectures based on zinc phthalocyanine (Pc) and imidazolyl-substituted perylenediimide (PDI), ZnPc/DImPDI/ZnPc 1 and ZnPc/ImPDI 2, have been prepared. A strong electron-donor, ZnPc-8, which contained eight tert-octylphenoxy groups was synthesized to ensure high solubility, thereby reducing aggregation in solution and providing ??-donor features while avoiding regioisomeric mixtures. Also, PDI units were functionalized with tert-octylphenoxy groups at the bay positions, which provide solubility to avoid aggregation in solution, together with one and two imidazole moieties in the amide position, PDI-6 and PDI-4, respectively, to be able to strongly coordinate with the ZnPc complex. Supramolecular complexation studies by (1)H NMR spectroscopy and ESI-MS demonstrate a high coordinative binding constant between imidazole-substituted PDI-4 or PDI-6 and ZnPc-8. The same results were confirmed by UV/Vis and fluorescence titration studies. UV/Vis titration studies revealed the formation of a 1:1 complex ZnPc/ImPDI 2 for the systems ZnPc-8 and PDI-6 and a 2:1 complex ZnPc/DImPDI/ZnPc 1 for the interaction of ZnPc-8 and PDI-4. The binding constant in both cases was determined to be on the order of 10(5) M(-1). Femtosecond laser flash photolysis measurements provided a direct proof of the charge-separated state within both supramolecular assemblies by observing the transient absorption band at 820 nm due to the zinc phthalocyanine radical cation. The lifetimes of charge-separated states are (9.8±3) ns for triad 1 and (3±1) ns for dyad 2. As far as we know, this is the first time that a radical ion pair has been detected in a supramolecular assembled ZnPc-PDI system and has obtained the longest lifetime of a charge-separated state published for ZnPc-PDI assemblies.</P>

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>

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.