Special Prisoners for Nuclear Plants

In power generation facilities, and particularly in the nuclear sector, fastening systems play a crucial role in ensuring safety, stability and resistance to the most extreme operating conditions. Components must withstand high temperatures, high pressures and corrosive environments. All while maintaining consistent mechanical performance over time.

For this reason, studs for nuclear power plants are made from high-performance materials and with specific geometries, custom-designed to fit perfectly with the needs of the most critical applications.

Custom-made prisoners for the nuclear industry

An excellent example of this type of fastener is the turned stud with reduced shank, made by EFS to specific customer design for applications in the nuclear industry.

• Dimensions: diameter M45, length 442 mm, thread pitch 4.5 mm.
• Material: 21CrMoV5-7 (1.7709), a special alloy steel with exceptional mechanical strength, thermal stability and resistance to high pressures.
• Custom design: asymmetrical ends and a milling on one end to facilitate attachment to other mechanical parts.

To ensure a perfect fit and optimal stress distribution, the stud is supplied with two M45 hex nuts made of 24CrMo5, a material with differentiated strength to optimize the bolt-nut connection. In addition, the nut includes an integrated collar, which acts as a washer and ensures proper thickness and force distribution.

Custom marking and quality control

Upon request, EFS can provide customized laser markings on the nut head or other specific locations for immediate and secure traceability. Each batch undergoes rigorous quality control, ensuring excellent performance even under the harshest conditions.

In addition to nuclear power plants, these captives are successfully used in turbines and heat exchangers in the power and Oil & Gas industries.

Product data sheet

• Diameter: M45
• Length: 442 mm
• Thread pitch: 4.5 mm
• Material: 21CrMoV5-7 (1.7709)
• Nuts provided: 2 M45 nuts in 24CrMo5 with integrated collar
• Applications: Nuclear plants, turbines, heat exchangers, oil & gas
• Customization: Special milling, laser marking on request