That hydrogen was produced by a mechanism involving the metal cladding of the nuclear fuel .
氢气是由电镀在核燃料棒外层的金属发生化学反应产生的。
Excessive deflection in a structure may cause considerable damage to cladding .
结构的过大挠度可以引起覆盖面的巨大破坏。
However , melting was a long ways from happening and at this time , the primary goal was to manage the core while it was heating up , while ensuring that the fuel cladding remain intact and operational for as long as possible .