The six decades exceptional performance of Zr
Advanced Materials for Light Water Reactor Fuels. Evolutionary and Recolutionary Nuclear Materials

Since the early 1960s and for the next 60 years more than 30 countries have decided to take advantage of the fission source of energy to produce clean and safe electricity. Currently there are more than 400 commercial Light Water Reactors (LWR) operating around the world. These power reactors can be classified either as Boiling Water Reactors (BWR) or Pressurized Water Reactors (PWR). The fuel in the reactors are uranium dioxide pellets stacked inside slender tubes or cladding made of a zirconium (Zr) alloy. The combination pair of the pellets and the cladding is called a fuel rod. Each rod is in general about 10 mm diameter and about 3-5 m long. In each reactor core there are thousands of rods assembled in bundles having approximately 100-250 rods in each bundle. The cladding plays a dual role :

(a) It protects the fuel pellets from the coolant water ;