Analysis and experiment of the hypervapotron mock-up for the EAST upgrade
During the EAST upgrade, the peak heat flux applied on the first wall components will be 2 MW/m2, which requires powerful cooling concept to decrease the component temperature, in order to simplify the material requirement and armor/heat sink module design. Hypervapotron is a promising method for high heat transfer coefficient, which bases on sub cooling boiling phenomenon, and has the potential to support the demand in several years (up to 20 MW/m2 with strong armor), and is chosen to be a candidate. The design contains a copper heat sink and uses water as coolant, a series of CFD analyses are performed to optimize the design, and a mock-up based on this optimization is assembled on a high heat flux test facility which employs electromagnetic induction heating and high speed photography; during the experiment under the required working conditions, the flowing status and thermal parameters are recorded. The analysis and experiment confirm the performance of the hypervapotron concept and the feasibility of the use in the EAST upgrade project.
Manufacturing and testing in reactor relevant conditions of brazed plasma facing components of the ITER divertor
Abstract A fabrication route based on brazing technology has been developed for the realization of the high heat flux components for the ITER vertical target and Dome-Liner. The divertor vertical target is armoured with carbon fiber reinforced carbon and tungsten in the lower straight part and in the upper curved part, respectively. The armour material is joined to heat sinks made of precipitation hardened copper–chromium–zirconium alloy. The plasma facing units of the dome component are based on a tungsten flat tile design with hypervapotron cooling. An innovative brazing technique based on the addition of carbon fibers to the active brazing alloy, developed by Ansaldo Ricerche for applications in the field of the energy production, has been used for the carbon fiber composite to copper joint to reduce residual stresses. The tungsten–copper joint has been realized by direct casting. A proper brazing thermal cycle has been studied to guarantee the required mechanical properties of the precipitation hardened alloy after brazing. The fabrication route of plasma facing components for the ITER vertical target and dome based on the brazing technology has been proved by means of thermal fatigue tests performed on mock-ups in reactor relevant conditions.
Microwave source with enhanced radiation power based on orbitron MASERs
We have proposed the design of high power microwave source in a vacuum tube based on the theory of negative mass instability. The proposed source does not operate based on a slow-wave structure but instead makes use of accelerated charged particles. In our structure, an electron emitter injects the charged particles into to the cavity. Emitted particles move around the anode, which leads to electron acceleration and emission of electromagnetic waves with a specific frequency. In this paper, we have enhanced the output power and frequency of microwave source by variation of particles initial energy and the number of anodes incorporating their specific arrangement and applied voltages. Working at room temperature, compactness, wide bandwidth, and tunability of output frequency are among the advantages of the proposed source.