It appears that aceholmes is correct. The number is almost 5 times higher for the thermal conductivity of (one form) of carbon compared to silver. Short peices of CNT are likely poor thermal conductors over longer lengths.
Does anyone think a reactor will lower the half life of Sr90 from 51 years to ten years? Perhaps, I missunderstood?
Tests have shown CNT = carbon nano tubes retain most of their strength to more than 3000 degrees c, so I think everything else will boil before diamond melts. Carbon melts at 3550 degrees c, but graphite sublines at 3367 degrees c. Neil