Status on the W monoblock type high heat flux target with graded interlayer for application to DEMO divertor

Abstract The divertor is the key in-vessel plasma-facing component being in charge of power exhaust and removal of impurity particles. In DEMO, divertor target must survive an environment of high heat fluxes (∼up to 20 MW/m2 during transient) and neutron irradiation. This paper presents the first part of the development for the realization of an advanced actively cooled concept aiming at improving the quality of material joining. It is based on the use of a W/Cu functionally graded material (FGM) interlayer instead of the copper interlayer. For this preliminary development, the interlayer (∼25 μm) is made with PVD (Physical Vapor deposition) and composed of continuous gradient of W from 100% at the interior part of the tile to 0% at the external part while Cu varies from 0% to 100%. Hot isotactic pressing is realized to join the CuCrZr tube to W tile equipped with graded material. With infrared thermography (SATIR facility) and US non-destructive examinations, manufactured mock-ups show good interface quality.

[1]  C. Baxi.  Thermal hydraulics of water cooled divertors , 2001 .

[2]  Eliseo Visca,et al.  Design study of ITER-like divertor target for DEMO , 2015 .

[3]  M. Richou,et al.  Improvement of non destructive infrared test bed SATIR for examination of actively cooled tungsten armour Plasma Facing Components , 2013 .

[4]  C. Hernandez,et al.  Non-destructive examination of the bonding interface in DEMO divertor fingers , 2013 .

[5]  B. Riccardi,et al.  Fatigue lifetime of repaired high heat flux components for ITER divertor , 2011 .

[6]  M. Merola,et al.  Critical heat flux analysis and R&D for the design of the ITER divertor , 1999 .

[7]  E. Werner,et al.  Low cycle fatigue behavior of ITER-like divertor target under DEMO-relevant operation conditions , 2015 .

[8]  Frederic Escourbiac,et al.  ITER plasma-facing components , 2010 .

[9]  B. Riccardi,et al.  Recent development toward the use of infrared thermography as a non destructive technique for defect detection in tungsten plasma facing components , 2011 .

[10]  G. Pintsuk.  4.17 – Tungsten as a Plasma-Facing Material , 2012 .

[11]  Eliseo Visca,et al.  Progress in the engineering design and assessment of the European DEMO first wall and divertor plasma facing components , 2016 .

[12]  J. You,et al.  Interpretation of the deep cracking phenomenon of tungsten monoblock targets observed in high-heat-flux fatigue tests at 20 MW/m2 , 2015 .

[13]  Jeong-Ha You,et al.  Progress in the initial design activities for the European DEMO divertor , 2017 .

[14]  J.-H. You,et al.  European DEMO divertor target: Operational requirements and material-design interface , 2016 .

[15]  J. Aktaa,et al.  Numerical assessment of functionally graded tungsten/steel joints for divertor applications , 2011 .

[16]  Eliseo Visca,et al.  Potential and limits of water cooled divertor concepts based on monoblock design as possible candidates for a DEMO reactor , 2013 .

[17]  G. Federici,et al.  Conceptual design studies for the European DEMO divertor: Rationale and first results , 2016 .

[18]  F. Escourbiac,et al.  Infrared thermography inspection of the ITER vertical target qualification prototypes manufactured by European industry using SATIR , 2009 .