Nuclear
RAS Alloy supplies nuclear-grade nickel alloys for PWR steam generator tubing, reactor internals and core support structures.
Typical Alloy Grades
690 / 600 / X-750 / 718 / 625
PWR steam generator tubing — Inconel 690 (30% Cr for SCC immunity)
Reactor vessel internals and core barrel components — Inconel 600, 625
Control rod drive mechanism springs — Inconel X-750 (aged condition)
Primary coolant pump shafts and fasteners — Inconel 718
Spent fuel storage canister materials — Inconel 625, 690
Applicable Standards
Operating PWR plants worldwide experienced PWSCC in Alloy 600 MA steam generator...
Operating PWR plants worldwide experienced PWSCC in Alloy 600 MA steam generator tubing, requiring costly replacement.
Alloy 600 (15% Cr) is susceptible to intergranular SCC in primary water >300°C. Chromia passive film becomes unstable under PWR water conditions.
Industry migrated to Inconel 690 (30% Cr) with demonstrated PWSCC immunity for >30 years. RAS supplies IN690 tubing with controlled grain size and full ET.