A recent Chinese nuclear-grade import certification (HAF 604) allows Sandvik Materials Technology to now sell tube and pipe for nuclear applications made at its Sandviken, Sweden factory, alongside the steam generator and fuel cladding tube it has sold for years in China. Recent contracts include alloy 690 steam generator tubing to Taishan 2 EPR project suppliers, and alloy 690 steam generator tubing for contractors on AP1000 reactors Sanmen 2 and Xianning.

Global sales and marketing manager for nuclear tube and pipe Mikael Blazquez says, "It is not a sexy name, but if you take out steam generator and fuel tube, it is what is left in a nuclear power plant that is nuclear-classified. Tubes to heat exchangers, condensers, hydraulic systems, instrumentation systems, these kinds of applications." (There is no difference between tube and pipe, except that pipe is bigger. Sandvik supplies product from 6mm-260mm in diameter, with wall thicknesses down to 0.1 mm).

Not that this is small potatoes, exactly; Blazquez estimates up to 1000 tons of pipe and tube per new reactor. There are 28 such reactors under construction in China, and another 17 to start construction in the next few years to meet targets of 58 GW installed nuclear generation capacity by 2020, according to market research firm UxC.

As an established supplier of highly-engineered tube and pipe, Sandvik’s approach to the fabricators that buy tube to supply the Chinese nuclear new-build market is simple: quality. "We as a company focus on the most stringent specifications. There is a lot of tube and pipe in nuclear power plants, but not all of it is nuclear-classified," Blazquez says, adding: "We focus on areas close to the reactor core, with higher safety classes and tougher requirements. That limits the volumes we are aiming for."

Other suppliers of nuclear tube and pipe include Valinox Nucléaire of France, which also markets products in China, Plymouth Tube Co of the USA and Sumitomo Metal Industries of Japan.

Blazquez says that the Chinese nuclear market is not as price-sensitive as people might think. "Chinese authorities take safety very seriously; they were the first country in the world to take strong action after Fukushima to put projects on hold and to do safety reviews, and they did it very quickly. They are very eager to have good quality. When we have discussions with the customer, price is important, but it never wins out over quality."

Having made the product to spec, the logistics of its delivery is the second crucial factor to the Chinese new-build supplier, Blazquez says. Delivery position is more important than lead time. The product must be there when the construction crew is ready for it. "If you say you will deliver, you must deliver on time."
Sandvik supplies tube and pipe to fabricators that use them to create NPP components and sub-assemblies. Since pipes, as Blazquez puts it, need to be attached to something with something, Sandvik can also provide welding consumeables and works with qualified partners to supply complementary products such as fittings or flanges as part of a package.

Otherwise, he says, there is not much product development within existing designs, because the industry is so conservative; innovation generally only occurs at the time of development of a new nuclear power plant design, and the rest of the time suppliers must stick closely to the specification required by customers.
Achieving the required quality is no mean feat. "We have to meet our specifications in every batch, with every tube, every time. There are very tough requirements on material properties, dimensional tolerances or surfaces, and even in their handling; they [the tubes] have to be treated in a certain specific way, through the whole production process."

He says that the company’s quality control processes start from the melt stage (material contents analysis) through each stage of production, including extrusion, pilgering (rolling under pressure), annealing, straightening, pickling, and inspection, testing and marking. Along the way, workers compile a ‘history book’ dossier full of stamps and test reports. "It is all about tracking, and building trust, but you need evidence to have trust," Blazquez says, adding: "Documentation is part of the delivery. We sometimes say that for every kilogram of tube we make, we produce 10kg of documentation."

Joking aside, demands for quality assessment continue to increase: "There are new protocols added on, but old ones are seldom taken out. For example, we do hydro testing in some cases. However, that is not really needed when we do ultrasonic testing, because whatever we find in UT will cover up what we find in hydro testing. But it is still in the specification because it has always been, and nobody is willing to take it out."

To help maintain quality standards, Sandvik operates an internal accreditation system that involves extra audits and staff training. Only five of its 13 steel mills around the world produce products for the nuclear industry: Sandviken, Scranton (Pennsylvania, USA), Arnprior (Ontario, Canada), Précitube (Charost, France) and Chomutov, Czech Republic. (The Scranton and Arnprior sites are currently in the process of applying for HAF 604 qualification as well).

Sandvik Materials Technology has set up a new factory in Zhengjiang, China, that is currently producing seamless stainless steel tubes for non-nuclear instrumentation and heat exchangers. When asked whether the company would consider setting up nuclear manfacturing there, Blazquez replies, "absolutely," but does not say when; first, the factory needs to build up sufficient nuclear experience. He says that using a factory in China is something that the company is aiming for: "Having local production will definitely strengthen our position in the Chinese nuclear market."