Keywords: austenitic stainless steel, non-metallic inclusions, end grain corrosion, intergranular corrosion, delta ferrite, oxide embedment, seam free welds, nuclear fuel cycle, nuclear power, nuclear energy, nitric acid, welding, nuclear fuel reprocessing, nuclear waste management
Controlling corrosion in the back end of fuel cycle using nitric acid grade stainless steels
The materials for use in nitric acid service have to be resistant to intergranular corrosion and have low general corrosion rates. End grain corrosion resulting from inclusions and segregation along dislocation bands needs to be minimised. The Nitric Acid Grade of stainless steel resistant to these corrosion problems has been indigenously produced. It is emphasised that proper fabrication practices have to be employed for NAG grade to take full advantage of its cleanliness, controlled chemistry and microstructure. The problems associated with fabrication of large diameter pipes, oxide embedment and welding are described with our experience in its production and quality assessment.