Short answers, pulled from the story.
German chemist Martin Klaproth discovered zirconium in 1789 while examining a gemstone from the island of Ceylon. He named the element Zirkonerde after the Persian word zargun which translates to gold-like or as gold.
Jöns Jacob Berzelius obtained zirconium in an impure state in 1824 by heating a mixture of potassium and potassium zirconium fluoride in an iron tube. Anton Eduard van Arkel and Jan Hendrik de Boer developed the crystal bar process in 1925 to produce the first industrial metallic zirconium.
The Kroll process was developed by William Justin Kroll in 1945 to reduce zirconium tetrachloride with magnesium. This method superseded the crystal bar process because it was much cheaper and more efficient for large-scale production.
Hafnium has a neutron absorption cross-section 600 times greater than that of zirconium which would halt the chain reaction in nuclear reactors. Commercial zirconium metal typically contains between 1 and 3 percent of hafnium so separation schemes are required to ensure fuel rods function correctly.
Zirconium reacts rapidly with water above 900 degrees Celsius to produce hydrogen gas which contributed to the Fukushima I Nuclear Power Plant disaster of the 11th of March 2011. The resulting hydrogen-oxygen mixture exploded and severely damaged the installations and at least one of the containment buildings.
The element has five stable isotopes including 90Zr, 91Zr, 92Zr, 94Zr, and 96Zr. 90Zr is the most common isotope making up 51.45 percent of all zirconium.