Transition Metal, Symbol Zr, Nuclear Reactor Uses
Puzzle 14 of Periodic Table Medium Pack
Question is: Transition Metal, Symbol Zr, Nuclear Reactor Uses
and the answer is: ZIRCONIUM
Word Meaning:
ZIRCONIUM — A chemical element (symbol Zr) with an atomic number of 40, a strong, lustrous, grey-white transition metal mainly used as a refractory and opacifier.
Definitions from Wiktionary.