B09 · Nuclear Power
Stainless Steel Plates for Nuclear Power: 316L/304L Selection and 6 Part Lists
In nuclear power, we have organized six parts using stainless steel: commonly used 316L / 304L / 316LN, with thickness ranging from 2–900 mm.
6 Parts and Material List
| Part / Component | Recommended Grade | Specification / Thickness | Surface | Main Failure Modes | Reference Standards |
|---|---|---|---|---|---|
| Reactor Coolant Main Headers (Hot Section/Cold Section) | 316LN (Forged)/CASS (CF3/CF3M/CF8M) | φ700–900mm; 60–100mm thick (e.g. φ798×75mm) | Forging Surface/Molten Surface/Grooved | Environmental Fatigue: One-Loop Water Chemistry (dissolved oxygen/temperature) may not be conservative for ASME III fatigue curves; CASS at 280–320°C long-term service → thermal aging ductility decreases | ASME BPVC III；RCC-M；GB/T 17569 |
| Nuclear Grade Pipes/Bends/Fittings | 304L/316LNuclear Grade/316LN | DN15–DN900 | Pickling/Degreasing | Cl⁻ Erosion + SCC + Fatigue; Boric Acid Leakage Corrosion | ASME III；RCC-M；GB/T 17569 |
| Main Pump Casing | 316LCF3M Cast-Forged | Large Cast-Forged Parts | Forging Surface/Grooved Surface | One-Loop Water Corrosion + Thermal Fatigue + High Cycle Fatigue | ASME III；RCC-M |
| Valves for Nuclear Grade | 316L/316NG/CF8M/CF3M | DN15–DN600 | Cast and Machined Surfaces/Tinned | Friction of Sealing Elements + Cl⁻ Erosion + Fatigue + Earthquake Load | ASME III；RCC-M；GB/T 12224 |
| Structural Supports/Embedded Components | 304L/316L | Steel Profiles/Welded Plates 5–30mm | 2B/Arc Cleaning | Corrosion + Earthquake / Thermal Expansion Load + Fatigue | ASME III；GB/T 3280 |
| Containment Liners/Fuel Assemblies | 304L | Liners 3–6mm; Fuel Assemblies 2–5mm | 2B/Arc Cleaning/Tinned | Boric Acid H₃BO₃+Cl⁻ → Erosion and Stress Corrosion Cracking (SCC); Radiation-Induced Corrosion | ASME III；GB/T 3280 |
Inside the table isStandard Configuration.The same part can be changed from 304 to 316L or 2205 depending on the medium, temperature, and welding method. Clearly stating the usage conditions saves more effort than specifying grades directly.
Key Points in Material Selection
- The most common grades used are 316L (4), 304L (3), and 316LN (2). The numbers in parentheses indicate the number of parts involved, which can serve as a starting point for quoting and material preparation.
- Common Corrosion Sources: Chloride and Salts (Pitting, Crevice Corrosion) (3/6 Hits).
- High Temperature Adds Hot Fatigue and Oxidation; Consider 310S / Heat-Treated Castings (3/6 Hits).
- Thickness Range 2–900 mm: Thin Sheets Are Formed Parts (Consider Bending Recoil and Deep Drawing Cracks), Thick Sheets Are Welded Structures (Consider Heat Input and Sensitization).
Common Issues
Which stainless steel is used most for nuclear power plants?
By total number of parts, 316L (4), 304L (3), and 316LN (2) appear the most. Specific to a part still depends on the medium and temperature, e.g., stainless countertops require switching from 304 to 316L when exposed to saltwater.
Which parts are prone to problems?
By failure description, typical is "reactor coolant header pipe (hot segment/cold segment)": environmental fatigue: one-loop water chemistry (dissolved oxygen/temperature) makes ASME III fatigue curves potentially conservative; CASS at 280–320°C long-term service → thermal aging ductility decreases; recommended grades 316LN (forged)/CASS (CF3/CF3M/CF8M), φ700–900mm; wall thickness 60–100mm (e.g., φ798×75mm). For this condition, it's recommended to specify medium concentration, temperature, and cleaning method during the design phase.
What thickness should I choose?
Thickness range in the list is 2–900 mm. For thin plates, consider forming and surface quality; for thick plates, welding and structural strength. Different equipment manufacturers may have different values for the same part; review your drawing or operating conditions.
Related materials and adjacent industries
Applications6
Thickness2–900mm
Grades900/316L