The T-54 and T-55 tanks are a series of Soviet main battle tanks introduced in the years following the Second World War. In 1961, development of improved NBC protection systems began. The goal was to protect the crew from fast neutrons; adequate protection against gamma radiation was provided by the thick armour and a PAZ basic NBC protection system. The POV plasticized lead antiradiation lining was developed to provide the needed protection. It was installed in the interior, requiring the driver's hatch and the coamings over the turret hatches to be noticeably enlarged. This liner had the added benefit of protecting the crew from fragments of penetrated armour.
