This approach is more than an idea, it is a tested prototype. R&D on the hot fusion reactor has verified that this concept can move heat at 10 megawatt/M2 or equiqently 1000 watts/cm2. These tests on this concept has verified a robust solution with no degragation seen after 500 heat up cycles.
Conclusion from the test report... It is possible to successfully fabricate a robust, all-refractory helium-cooled heatsink using existing porous metal technology. This high temperature heatsink removed substantial amounts of power even at low mass flow rates by taking advantage of large delta-Ts in the coolant. The heatsink survived over 500 thermal fatigue cycles at 3.5 MW/m2 with onlyminimal microcracking of the faceplate. Tungsten rod armor may be incorporated into the tungsten faceplate in advanced pfc designs without the problems of joining dissimilar materials. These heat exchangers exceeded design specifications and survived a maximum heat flux of almost 6 MW/m2 and a maximum surface temperature near 1000oC. However, the pressuredrop across each module was relatively high, exceeding 55 kPa. There remain problems with controlling porosity and clogging by contaminants. The porosity difference between the two modules in these experiments was as high as 30%. No evidence of mass flow instabilities was observed for the two modules in parallel even for very high delta-T in the helium. Nearly the same thermal response was obtained on each module. However, for a worst case scenario of an unrestricted flow bypass, a 39% reduction in mass flow occurred in the module resulting in a 42% reduction in power absorbed by the helium. This level of thermal performance is more than adequate for first wall applications exposed to a 2 MW/m2 heat flux. However, better performancecould be obtained if the porosity could be doubled. This would almost triple the mass flow and power handling capability. Such an innovation could open a design window into the divertor heat flux regime of 20 to 30 MW/m2 and make high temperature,helium-cooled refractory heatsinks a viable alternative to liquid metal pfcs.
