Experiences in Manufacturing and Qualifying of Stainless Steel AISI 403 Grade materials for PHWR reactors of NPCIL

摘要

NPCIL uses stainless steel AISI 403 grade material extensively for very critical nuclear components. A very special application of this material is for manufacturing END FITTING BODY of "COOLANT CHANNEL ASSEMBLIES" of Pressurized Heavy Water Reactor (PHWR) of Nuclear Power Plants. Presently, two types of PHWR Nuclear Plants viz 220 MWe and 540 MWe are under operation in India. Next higher rating viz 700 MWe PHWR Nuclear Plants are at various stages of construction and due for commissioning in near future. There are number of Pressure Tubes in PHWR Nuclear Plants wherein fuel is loaded and are called coolant channel assemblies. End fitting bodies are assembled on either end of PRESSURE TUBES of coolant channel assembly. The Coolant (Heavy water) flows inside these assemblies and collects the heat produced during nuclear reaction in pressure tubes. This heat is utilized to produce Steam in Steam Generators. After giving up heat in Steam Generator, coolant returns to pressure tube and cycle continues.