Much of the vessel, including the 4 vessel rings from the core beltline to the bottom head, is made from single forging. The vessel has no nozzles greater than 2 inches in diameter anywhere below the top of the core because the external recirculation loops have been eliminated. Because of these two features, over 50% of the welds and all of the pipings and pipe supports in the primary system hav e been eliminated and, along with it, the biggest source of occupational exposure in the BWR.