The fuel elements contained fuel rods 3.1 m long , 31 mm in diameter .
The fuel elements contained fuel rods 3.1 m long , 31 weighing 55 kg , containing uranium fuel and sheathed in aluminium .
The fuel elements contained fuel rods 3.1 m long , 31 mm in diameter and weighing 55 kg , containing uranium fuel and sheathed in aluminium .