EDIT:
Emendare: I now need a proton lazer for.... reasons
The first can use heac.
Checking the wiki, the following elements conduct heat well, do not conduct electricity, and are destroyable.
SPNG
ISZS
HYGN
BTRY
BRCK
Note that none of these will ever be as good as HEAC.
HEAC uses special code to make it more conductive than every other element, even the ones that have the same heat conductivity value. A cooling loop would have different strengths (coolant can be cooled faster than HEAC) and weaknesses (coolant cools other elements slower than HEAC)
That's neither breakable nor burnable.
Then add snow(bomb) next to it.
Hey, that's cheating!