Problem of hydrogen embrittlement:

To address the problem of hydrogen embrittlement, emphasis is placed on controlling the amount of residual hydrogen in steel, controlling the amount of hydrogen pickup in processing, establishing alloys along with improved resistance to hydrogen embrittlement, establishing low or no embrittlement plating or coating processes, and restricting the amount of in-situ (in position) hydrogen introduced during the service life of a element.

Hydrogen embrittlement is a problem along with zirconium and zirconium alloys that frequently are used as cladding materials for nuclear reactors.  Zirconium reacts along with water as follows.

Zr + 2 H₂O→ ZrO₂  + 2H₂↑

Part of the hydrogen generates through the corrosion of zirconium in water merges along with the zirconium to form a divided phase of zirconium hydride (ZrH_1.5) platelets. The metal after that becomes embrittled (ductility decreases) and it fractures simply.   Cracks starts to form in the zirconium hydride platelets and are propagated by the metal. Zircaloy-2 (a zirconium alloy), that has been used as a fuel rod cladding, might absorb as much as 50 percent of the corrosion- generates hydrogen and is subject to hydrogen embrittlement, especially within the vicinity of the surface. A  Studies at Westinghouse, Batelle, and elsewhere have revealed in which the nickel in the zircaloy-2 was responsible for the hydrogen pickup. This has led to the development of zircaloy-4 that has significantly less nickel than zircaloy-2 and is less susceptible to embrittlement.  Further, the introduction of niobium into zircaloy-4 additional decreases the amount of hydrogen absorption.