BUMAX advanced fastener solutions for demanding fusion energy applications


The comprehensive BUMAX range of stainless steel fasteners provides engineers with high-performance fastener solutions on fusion energy test projects around the world.

Fusion reactors have the potential to power the world, although fusion scientists and engineers are still developing the technology and overcoming the technical challenges. Various pilots and experiments are being conducted around the world to test different aspects of the fusion technology.

These tests place significant demands on critical components such as fasteners. Depending on their location in the reactor, non-treated stainless steel fasteners are required that have high-strength, low-magnetic permeability, good material properties and certain demands on chemical composition.

“Many engineers working on fusion projects simply don’t know our products exist or they are unaware of the range of solutions that are available. For example, customers often use expensive temperature resistant stainless steel materials such as Grade 660 (EN 1.4980) or Alloy 718 (EN 2.4658) in applications that may not necessarily benefit from the properties provided by those material,” says Camille Feuillet, BUMAX Business Development Manager France. “But BUMAX offers a range of options (including some that are off the shelf) that can offer a much more cost-effective solution, often having the desired properties to cope even better with the various demanding applications found in fusion technology.”

Optimal fastener solutions for fusion research

But fusion engineers are increasingly becoming aware of the benefits of the BUMAX fastener range. BUMAX fasteners have recently been approved by a fusion customer building a prototype in France, and BUMAX is in discussion with other potential customers conducting fusion tests in the UK, the US, Italy and Spain.

“BUMAX® 88 and BUMAX® 109 are austenitic stainless-steel grades that provide very-low magnetic permeability, high strength and very consistent material properties,” explains Feuillet. “BUMAX® NITRO 109 is a new product grade from BUMAX. This is another austenitic grade that provides these same properties, while still retaining its high-strength capabilities in much larger dimensions – up to M36.”

With the plasma in the fusion reactor reaching over 100 million degrees Celsius, it needs to be held in place by a magnetic field. For these reasons, low magnetic permeability and sufficient temperature resistance for joints are important features in fusion reactors.

Chemical composition is also essential and fusion engineers set limitations on material composition requirements for elements such as cobalt, tantalum and niobium.

“At BUMAX, we only source the highest quality stainless steel from European suppliers and our long-term collaboration with them ensures we can meet the most stringent chemical composition requirements for BUMAX products,” says Feuillet. “The high quality of our stainless steel is essential for the consistency of our products in all customer applications.”

Reduced galling

One key feature of BUMAX fasteners is their low risk of galling, which can be a common challenge with generic stainless steel fasteners that severely impacts the reliability and integrity of an assembly. However, for more specialist applications, BUMAX is also able to offer an additional range of surface treatments and coatings dependent on the application requirements.

“Another competitive advantage we have is our unique silver coating on BUMAX® products to reduce galling. The coating avoids the use of grease, which cannot be used in many parts of the reactor,” says Feuillet.

Since the 1990s, BUMAX has collaborated with CERN and their Particle Accelerators in Switzerland to successfully trial the use of this silver coating on BUMAX® products to further reduce any risks of galling, developing into CERN’s 507 norm for High Vacuum and Magnetic Field Applications. Since these successful trials with CERN, BUMAX has started to offer this product to other customers within the fusion energy sector.

The massive potential of fusion

With the environmental challenges facing the planet and society’s ever-increasing thirst for energy, fusion represents a significant opportunity to potentially change our reliance on environmentally damaging and less efficient sources of energy.

Work is currently underway in several countries around the world and fusion technology represents a truly international effort in science and engineering. BUMAX boasts a global network of direct technical representatives and distributors that are well positioned to support these efforts with a range of high-performance products, as well as unique manufacturing capabilities and technical expertise from its base in Sweden.

For further details and contact information see: https://www.bumax-fasteners.com/market-segments/fusion-nuclear-energy-sciences/

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