Zirconium…

Zirconium is the 40^th element on the periodic table; a metal with the symbol Zr. It is similar to titanium and is used in alloys where its resistance to corrosion will be helpful. It has been in the news recently as zirconium alloys are used to hold the uranium pellets in the boiling water reactors found in the Fukushima Daiichi power plants in Japan.

The nuclear fuel becomes hot as the uranium atoms break apart, this heat is used to boil water and the subsequent steam is used to turn a turbine just like any other power station. The fuel rods operate at a temperature of 285 °C. At this temperature, the zirconium is relatively inert. After the earthquake, the pumps circulating the water stopped functioning and the temperature started to increase. At temperatures above 900 °C, the zirconium is able to reduce water producing zirconium oxide and hydrogen gas.

Zr + 2H₂O → ZrO₂ + 2H₂

zirconium + water → zirconium oxide + hydrogen

The hydrogen produced eventually exploded causing further structural damage. We have seen temperature affecting the reactivity of metals before. Magnesium and iron barely react with water at room temperature but both can be made to reduce steam.

Questions…

1. Put zirconium, magnesium and iron into an order of decreasing reactivity.
2. Given the information above, what predictions can you make about the appearance of
   • zirconium
   • zirconium oxide
3. What device converts kinetic energy to electrical energy?
4. Give me two examples of a
   • Group I metal
   • Noble gas
   • Halogen