High heat flux tests on heat sinks armored with tungsten rods

This paper presents the results of high heat flux tests at Sandia National Laboratories of mock-ups armored with W rods embedded in water-cooled copper-alloy heat sinks. The major result is the excellent performance of these mock-ups in thermal response tests at up to 30 MW/m2 and in thermal cycling tests of 500 cycles (10 s on, 10 s off) at ∼25 MW/m2. Melting of rod tips and the subsequent ‘self-repair’ of a degraded thermal bond were seen. Issues for further development in both testing and manufacturing of the mock-ups were identified. Evaluation of the surface heat flux was found to be somewhat problematic and this issue is discussed.