New Development in PHWR Fuel Assembly Fabrication

Abstract

In the conventional process of PHWR fuel assembly fabrication, zircaloy-4 bearing and spacer pad welding is carried out on the zircaloy-4 fuel sheaths after loading and encapsulation of the U02 fuel pellets. In some cases, this method could lead to damage of the pellets and protective graphite coating on the inner surface of the zircaloy-4 sheath. To overcome this problem, a novel method has been developed, where appendages are first welded on empty fuel sheaths by supporting from inside followed by loading of pellets and encapsulation.