Stainless Steel Coil Tube for Nuclear Main Pump High-Pressure Coolers
Product Overview
The stainless steel coil tube (Coiltube) is a precision-engineered tubing product designed for demanding industrial and nuclear applications, particularly in nuclear main pump high-pressure cooler systems. Manufactured by Wenzhou Jixing Metal Materials Co., Ltd, this coil tube is formed through a specialized cold-bending process that produces continuous, seamless spiral tubing configurations with exceptional dimensional accuracy and structural integrity. The product is developed in accordance with rigorous nuclear-grade manufacturing standards, ensuring reliability under extreme pressure and thermal conditions inherent to nuclear power plant cooling circuits.
The coil tube represents a critical component in nuclear main pump high-pressure cooler assemblies, where it serves as the primary heat exchange medium. The manufacturing process development for this application required extensive research into material behavior under cyclic thermal loads, radiation environments, and sustained high-pressure differentials—challenges that distinguish nuclear-grade coil tubes from conventional industrial equivalents.
Material & Properties
The coil tube is fabricated from high-performance austenitic stainless steel grades, selected for their superior corrosion resistance, mechanical strength, and weldability in nuclear service environments.
- Primary Material Grades: AISI 304 (UNS S30400), AISI 316L (UNS S31603), and 321 (UNS S32100) austenitic stainless steels
- Alternative Nuclear-Grade Grades: 316H (UNS S31609), 304H (UNS S30409), and custom nuclear alloy compositions meeting ASTM A213/A778 specifications
- Corrosion Resistance: Excellent resistance to pitting, crevice corrosion, and stress corrosion cracking (SCC) in high-temperature water and nuclear coolant environments
- Mechanical Properties: High tensile strength (≥515 MPa), yield strength (≥205 MPa), and elongation (≥40%) at room temperature, with maintained performance up to 600°C
- Thermal Stability: Low thermal expansion coefficient and excellent resistance to thermal fatigue under cyclic operating conditions
- Weldability: Superior weldability with minimal sensitization risk, suitable for all standard welding processes including TIG (Tungsten Inert Gas) and orbital welding
- Radiation Resistance: Maintains mechanical properties under prolonged neutron irradiation exposure typical of nuclear reactor environments
Specifications
| Parameter | Specification |
|---|---|
| Product Type | Stainless Steel Coil Tube (盘管 / Coiltube) |
| Material Grades | AISI 304, 304L, 316, 316L, 321, 316H, 304H |
| Outer Diameter (OD) | 6 mm – 108 mm (customizable) |
| Wall Thickness | 0.5 mm – 8.0 mm (customizable) |
| Bend Radius | ≥ 1.5 × OD (minimum); typically 3 × OD for nuclear applications |
| Coil Length | 10 m – 500 m (continuous length, customizable) |
| Surface Finish | Pickled & Passivated (P&P), Electropolished, or Mirror Finish (Ra ≤ 0.4 μm) |
| Tolerance on OD | ±0.1 mm (standard); ±0.05 mm (precision grade) |
| Tolerance on Wall Thickness | ±10% (standard); ±5% (precision grade) |
| Operating Temperature Range | −196°C to +600°C |
| Maximum Working Pressure | Up to 15 MPa (150 bar) depending on geometry |
| Standards Compliance | ASTM A213, ASTM A778, ASME B31.3, EN 10216-5, GB/T 12771, NB/T 20017 |
| End Treatment | Plain ends, Beveled ends, Threaded ends, or custom fittings |
| Heat Treatment | Solution Annealing (1050°C – 1150°C), Pickling & Passivation |
Manufacturing Process
The manufacturing process for nuclear-grade stainless steel coil tubes is a multi-stage, tightly controlled procedure that ensures traceability, dimensional precision, and metallurgical integrity throughout production. The process development for nuclear main pump high-pressure coolers specifically addressed challenges in maintaining material properties during cold forming at large-scale spiral configurations.
1. Raw Material Selection & Inspection
- Premium-grade stainless steel seamless tubes or welded tubes sourced from certified mills
- 100% chemical composition verification via optical emission spectrometry (OES)
- Material traceability through heat number tracking and Mill Test Reports (MTRs)
- Incoming quality inspection per ASTM A781/A999 testing protocols
2. Pre-Treatment & Preparation
- Solution annealing to relieve residual stresses and restore full austenitic microstructure
- Pickling and passivation to remove surface scale and establish protective chromium oxide layer
- Dimensional inspection and sorting based on OD and wall thickness tolerances
- End preparation: deburring, chamfering, and alignment verification
3. Coil Forming (Cold Bending)
- Precision CNC-controlled coil forming using mandrel-assisted bending systems
- Controlled bending speed and tooling geometry to minimize ovality and wall thinning
- Real-time monitoring of bend radius, coil pitch, and dimensional conformity
- Post-bend inspection for ovality (≤ 2% of OD), wall thickness reduction (≤ 5%), and surface integrity
- Special attention to maintaining metallurgical properties through the forming process—critical for nuclear applications where work hardening must be controlled
4. Post-Forming Heat Treatment
- Stress relief annealing to eliminate residual stresses introduced during cold forming
- Temperature-controlled furnace annealing (1050°C – 1150°C) followed by controlled cooling
- Final pickling and passivation to restore surface chemistry
5. Quality Assurance & Testing
- Hydrostatic pressure testing per ASTM A999 (minimum 1.5× working pressure, 5-minute hold)
- Non-Destructive Testing (NDT): Eddy current testing (ECT) for internal and external defects
- Dye penetrant testing (PT) for surface crack detection
- Dimensional verification using laser measurement systems and CMM (Coordinate Measuring Machine)
- Microstructural examination via metallographic analysis (optional, for nuclear certification)
- Full traceability documentation package including heat numbers, process parameters, and test results
6. Packaging & Delivery
- Protective wrapping with VCI (Vapor Corrosion Inhibitor) film and cushioning material
- Custom wooden crates or steel containers for transport protection
- Complete documentation: MTRs, NDT reports, dimensional certificates, and material conformity certificates
Applications
The stainless steel coil tube from Wenzhou Jixing Metal Materials Co., Ltd is engineered for the most demanding industrial and nuclear applications:
- Nuclear Power Plants: Main pump high-pressure coolers, intermediate heat exchangers, reactor coolant system piping, and secondary circuit heat exchangers
- Chemical Processing: High-pressure heat exchangers, distillation column internals, and reactor coil assemblies
- Petrochemical Industry: Crude oil heat exchangers, catalytic reformer coil tubes, and gas processing facilities
- Pharmaceutical Manufacturing: Sanitary-grade heat exchangers and process piping requiring high purity and cleanability
- Food & Beverage Industry: UHT (Ultra-High Temperature) processing equipment and heat recovery systems
- Power Generation: Condenser tubes, economizer coils, and superheater assemblies in fossil-fuel and combined-cycle power plants
- Oil & Gas: Subsea heat exchangers, wellhead coil assemblies, and offshore platform piping systems
- Aerospace: Hydraulic system coils, fuel cooling loops, and thermal management systems
Quality Certifications & Standards Compliance
All products are manufactured under a comprehensive Quality Management System (QMS) with the following certifications and standards compliance:
- ISO 9001:2015 — Quality Management System certification
- ISO 14001:2015 — Environmental Management System certification
- ISO 45001:2018 — Occupational Health and Safety Management System certification
- ASME "U" Stamp — Pressure Vessel and Piping certification (where applicable)
- NB/T 20017 — Chinese nuclear industry standard for nuclear power plant piping components
- ASTM A213 / A778 — Standard specifications for austenitic stainless steel tubes
- EN 10216-5 — European standard for stainless steel tubes for heat exchangers
- GB/T 12771 — Chinese national standard for welded stainless steel tubes
- ASME B31.3 — Process piping code compliance
- API 5L — Pipeline tube specifications (where applicable)
- Third-Party Inspection (TPI) — Available upon customer request from recognized inspection agencies
Unique Selling Points
Nuclear-Grade Process Expertise: Wenzhou Jixing Metal Materials Co., Ltd has developed specialized manufacturing processes for nuclear main pump high-pressure cooler coil tubes, demonstrating deep domain expertise in the unique metallurgical and dimensional challenges of nuclear applications.
- Full Traceability: Complete material and process traceability from raw material heat number through final product delivery, meeting nuclear industry audit requirements
- Precision Coil Forming: Advanced CNC coil forming technology ensuring tight dimensional tolerances (ovality ≤ 2%, wall thickness reduction ≤ 5%) even at large spiral configurations
- Nuclear Application Heritage: Manufacturing processes developed specifically through nuclear main pump high-pressure cooler projects, with documented lessons learned integrated into standard procedures
- Multi-Grade Capability: Production capability across all major austenitic stainless steel grades including high-temperature and high-strength variants (304H, 316H)
- Comprehensive Testing: Full NDT suite including eddy current, hydrostatic pressure, and dye penetrant testing ensuring defect-free product delivery
- Custom Engineering: Flexible customization of dimensions, surface finishes, end treatments, and coil configurations to meet specific application requirements
- International Standards Compliance: Products manufactured to meet both Chinese national standards (GB) and international standards (ASTM, ASME, EN), facilitating global project deployment
- Quality-First Philosophy: 100% inspection protocols with zero-defect tolerance for nuclear-grade applications, supported by a fully certified QMS
Technical Documentation Package
Each shipment includes a comprehensive technical documentation package comprising:
- Mill Test Reports (MTRs) with full chemical composition and mechanical property data
- Material Conformity Certificates (MCCs) per EN 10204 3.1
- Non-Destructive Testing (NDT) reports with pass/fail documentation
- Hydrostatic Pressure Test certificates
- Dimensional Inspection reports with as-built measurements
- Process Parameter Records documenting heat treatment, forming, and surface treatment conditions
- Weld Records (if applicable) with welder qualification references
- Product Data Sheets with material specifications and recommended installation guidelines
Conclusion
The stainless steel coil tube product from Wenzhou Jixing Metal Materials Co., Ltd represents the culmination of specialized engineering expertise in nuclear-grade tubing manufacturing. Through rigorous process development, comprehensive quality assurance, and full standards compliance, these products deliver the reliability, precision, and traceability demanded by the nuclear industry and other high-integrity applications. The company's proven experience in nuclear main pump high-pressure cooler coil tube manufacturing positions it as a trusted supplier for critical industrial and nuclear infrastructure projects worldwide.