The current designs of large, new-build reactors have components that require transport to site individually, for subsequent assembly on-site once they arrive. The main containment vessel of a small reactor on the other hand will fit within the specifications of a single large reactor component. An AP1000 steam generator is 22.5 m ~(74 foot) long, 5.6 m ~(18 foot) diameter and weighs 700 t ~(1.5 X 106 lb). The same component in an EPR has similar dimensions but weighs 550 t ~(1.2 X 106 lb). Compare this to a small reactor where a complete integral unit can fit within the above envelope, and weigh less than 500 t ~(1.1 X 106 lb) and it becomes apparent that from a manufacturing perspective the components can be manipulated on the flowline with relative ease. The entire small reactor unit can now be transported as a single unit direct for installation to the site, moving more tasks to the factory to complete assembly in a controlled environment.

Integral reactors often have more numerous, smaller components per plant which lends itself to a flowline approach. For example, a typical large, new-build main coolant pump will weigh 124 t (2.7 X 105 lb), which represents a significant part to lift and negotiate in a manufacturing environment. In a small reactor, however, each pump may weigh only 500 kg (1100 lb). This is of a comparable magnitude to the aero-engine flowline model, so it seems appropriate to adopt this technique to the small reactor product.