Nuclear fuel rod tubes.
An example of the element Zirconium

The zirconium tubes are the ends of a long piece of tubing lathed into shorter lengths for the purpose of placing pellets of U238 for reactor function. I am acquainted with a machinist who works at a company that makes the special length reactor tubes. These short pieces of zirconium tubes are the left over pieces of the long tube after it is cut up in the special usable lengths. The purity of the zirconium is around 98.5% the other % is chrome, some iron, and ? Anyway, it is neat metal when used for certain experiments; When touching a revolving grind stone, it makes a shower of bright white sparks, the lathe turnings burn bright in air, try it in pure oxygen and better look at it through dark glasses! File some fine powder and mix it with potassium chlorate and if you light it with a fuse, it blows with 75% power of TNT! Even lighting the powder will make a blinding POOF! If powdered zirconium is wet, it will still burn with tremendous energy. The powder zirconium must be stored completely under water to be safely kept.
Zirconium is used in nuclear industry because it resists corrosion like no other metal and it is tough metal.
Larry