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
Frequently Asked Questions
Nuclear Alloy FAQWhy is Inconel 690 specified instead of Alloy 600 for steam generator tubing?
Inconel 690's ~30% chromium gives immunity to primary-water stress corrosion cracking (PWSCC). Tubing is supplied to ASTM B167 after a 1100°C solution anneal with a controlled grain-boundary carbide morphology report, and eddy-current inspection rejects any signal above 20% of wall — tighter than the code's 40% threshold.
What condition is Inconel X-750 supplied in for control rod drive mechanism springs?
Fully double-aged — 732°C for 16 h with air cool, then 621°C for 8 h — so gamma-prime structure resists relaxation at 315°C service temperature. Single-aged material will sag and extend rod drop time.
What QA documentation comes with nuclear-grade material?
ASME Section III NCA-3800 material certification, PMI on every piece, bobbin and rotating-probe eddy-current mapping, and full melt traceability to the VIM/VAR heat number. Inconel 718 pump shafts are double-aged and test above 1400 MPa tensile.