A new technique, called Vacuum Tight Threaded Junction (VTTJ), has been developed and patented by Consorzio RFX, permitting to obtain low-cost and reliable non welded junctions, able to maintain vacuum tightness also in aggressive environments. The technique can be applied also if the materials to be joint are not weldable and for heterogeneous junctions (for example, between steel and copper) and has been tested up to 500 bar internal pressure and up to 200° C. The main advantages with respect to existing technologies are an easy construction, a low cost, a precise positioning of the junction and a high repeatability of the process. Due to these advantages, the new technique has been adopted for several components of the SPIDER experiment and has been also recently accepted by the ITER vacuum group for the usage in the MITICA experiment, the full prototype of the ITER Neutral Beam Injectors. Recently, the VTTJ technique has been tested with geometry and materials compatible with the divertor and other components of future fusion reactors. Namely, a set of junction samples have been manufactured, joining CuCrZr to 316L stainless steel and using tube-to-tube geometry. Three different geometries of the steel part have been adopted in order to test possible alternatives that could be advantageous in terms of corrosion compatibility, especially in view of DEMO. The samples have been tested according to the ITER criteria for the qualification of the heterogeneous junctions of the ITER divertor. The main results of the test campaign are described in the paper.
Application of the VTTJ cold junction technique to fusion reactor relevant geometry and materials
Agostinetti P;Degli Agostini F;
2016
Abstract
A new technique, called Vacuum Tight Threaded Junction (VTTJ), has been developed and patented by Consorzio RFX, permitting to obtain low-cost and reliable non welded junctions, able to maintain vacuum tightness also in aggressive environments. The technique can be applied also if the materials to be joint are not weldable and for heterogeneous junctions (for example, between steel and copper) and has been tested up to 500 bar internal pressure and up to 200° C. The main advantages with respect to existing technologies are an easy construction, a low cost, a precise positioning of the junction and a high repeatability of the process. Due to these advantages, the new technique has been adopted for several components of the SPIDER experiment and has been also recently accepted by the ITER vacuum group for the usage in the MITICA experiment, the full prototype of the ITER Neutral Beam Injectors. Recently, the VTTJ technique has been tested with geometry and materials compatible with the divertor and other components of future fusion reactors. Namely, a set of junction samples have been manufactured, joining CuCrZr to 316L stainless steel and using tube-to-tube geometry. Three different geometries of the steel part have been adopted in order to test possible alternatives that could be advantageous in terms of corrosion compatibility, especially in view of DEMO. The samples have been tested according to the ITER criteria for the qualification of the heterogeneous junctions of the ITER divertor. The main results of the test campaign are described in the paper.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
