Alloy 304CO – Cobalt-Restricted Stainless Steel Plate for Nuclear Applications

Sandmeyer Steel Company offers Alloy 304CO (UNS S30400), a cobalt-restricted stainless steel plate specifically designed for applications in the nuclear industry. With the largest inventory of stainless steel, nickel alloy, and titanium plate products, we provide high quality 304CO to meet stringent industry requirements, ensuring exceptional performance in critical environments.

Available thicknesses for 304CO:

What is Cobalt-Restricted Stainless Steel?

Cobalt-restricted stainless steel, also referred to as low cobalt stainless steel, is produced with a maximum cobalt content of 0.05%. This critical specification supports low radiation activation, making the material ideal for use in nuclear power plants, radiation shielding, and other radiation-sensitive environments.

Alloy 304CO – Dual Certified Stainless Plate for Nuclear Service

We offer Alloy 304CO, a low cobalt modification of the widely used 304 stainless steel. This material delivers excellent corrosion resistance and mechanical strength, while meeting strict nuclear specifications.

Most thicknesses of Alloy 304CO are dual certified as:

• 304 / 304LCO (UNS S30403) – Preferred for applications requiring low carbon content for improved weldability
• 304 / 304HCO (UNS S30409) – Suitable for applications requiring increased strength at elevated temperatures

This dual certification provides flexibility in sourcing and application while maintaining full compliance with nuclear industry standards.

Nuclear-Ready Certifications and Material Quality

Our cobalt-restricted stainless steel plates meet the following industry requirements:

• ASME Quality Systems Certificate Holder for Material Organization (“MO”): Certified under QSC #619.
• 10 CFR 50 Appendix B and 10 CFR Part 21: Compliant with applicable sections of federal regulations governing nuclear safety and quality assurance.
• NQA-1: Compliant with applicable sections Nuclear Quality Assurance (“NQA-1”) standards for the nuclear industry.
• NIAC Member: Audited by the Nuclear Industry Assessment Committee (“NIAC”).These qualifications ensure that our materials meet the stringent demands of the nuclear industry – from new builds to ongoing plant maintenance.

 
Common Applications for Cobalt-Restricted 304 Stainless Steel Plate

• Nuclear power plant construction and maintenance.
• High-performing storage and containment solutions.
• Components requiring low cobalt and high corrosion resistance.
• Upgraded specification for advanced reactors and next-generation energy systems.

Plate Dimensions

Plate dimensions vary by grade, thickness, and mill availability.

Length

• Typical plate availability is 240–252″
• Longer lengths in excess of 300″ are available in select grades and thicknesses
• Shorter lengths may apply depending on thickness and mill availability

Width

• Common widths include 60″, 79″, 96″, and 120″

Thickness Considerations

• Maximum available length and width will vary as thickness increases

Plate is supplied based on actual dimensions. In-house processing is available to meet required sizes.

Why Choose Sandmeyer Steel Company

When you choose Sandmeyer Steel Company, you are partnering with a leader in the nuclear sector, committed to delivering excellence through quality assurance, traceability and documentation, decades of expertise, and a commitment to sustainability. Contact an expert today to request a quote or learn more about cobalt-restricted stainless steel plate for your nuclear project.