Evaluation of porous media heat exchangers for fusion applications

Several types of porous media heat exchangers are being evaluated for use in fusion applications. Broadly, these devices can be classified as capillary-pumped (heat pipes) or mechanically-pumped heat exchangers. Monel/water thermosyphon heat pipes with a porous metal wick are being evaluated for use in Faraday shields. A subscale prototype has been fabricated, and initial tests at Oak Ridge National Laboratory have shown favorable results. Alkali metal heat pipes have demonstrated absorbed heat flux capability of over 1000 MW/m2. An advanced gyrotron microwave cavity is being developed that uses water cooling in a mechanically-pumped copper porous metal heat exchanger. Tests on a prototype demonstrated absorbed heat flux capability in excess of 100 MW/m2. Porous metal heat exchangers with helium, water, or liquid metal coolants are being evaluated for plasma-facing component cooling. Tests on a helium/copper porous metal heat exchanger demonstrated absorbed heat flux capability in excess of 15 MW/m2. Applications, conceptual designs, fabricated hardware, and test results are summarized. 22 refs., 5 figs., 2 tabs