Sandvik Nuclear Tubes Extended to Reach 50-Year Service Life in Chinese Nuclear Power Plant

In May 2019, Qinshan Phase I–the First Nuclear Power plant in China–extended the lifetime of its reactor with Sandvik Alloy 800 nuclear tubes inside by 20 years to reach a total 50-year service life.

The background

Qinshan Phase I, where steam generators were fabricated by Shanghai Boiler Works, Shanghai Electric Group, based in Qinshan Town, China, has used Sandvik Alloy 800 tubes in its nuclear power plant since December 1991, originally intended for a lifetime of 30 years.

Sandvik was one of the first companies in China to supply this type of tube and was chosen as the customer’s trusted nuclear supplier in 1991.

In May 2019, after 25 years of the nuclear power plant being in operation, the customer made the decision to extend its lifetime with Sandvik tubes inside by an additional 20 years. The decision was made after the history of the steam generator’s trouble-free operation without any plugged tubes or quality issues to date since the start of its operation.

The Sandvik solution

With almost 60 years of experience in the nuclear industry, Sandvik has supplied nuclear tubes to more than 100 nuclear plants worldwide. The tubes are manufactured in Sandvik’s own state-of-the-art tube mill in Sweden to ensure they are fully traceable from melt to finished product.

The Sandvik grade used, Sanicro® 30, is a low-carbon version of Alloy 800 austenitic nickel-iron-chromium alloy, which can tolerate temperatures up to 550°C (1020°F). This grade offers good resistance to stress corrosion cracking and intergranular corrosion making it ideal for steam generator tubing in nuclear stations.

The result

After 25 years of operation, the initial tubes supplied in 1991 are still in such good condition that the customer does not need any repair or replacement of any tube when they want to extend the lifetime of the nuclear power plant by an additional 20 years from its original design lifetime, meaning these nuclear tubes will reach a 50-year service life.

Because of the quality and performance of this Sandvik grade, the tubes showed almost no difference from the initial data, signifying there is no loss after 25 years of operation. This absence of required maintenance means tremendous time and cost savings in the life of a nuclear station.

“We learnt that Qinshan Unit 1 nuclear power plant had conducted an overhauling check in 2019, and during this process, the U-tube bundles from Sandvik had no occurrence of plugging,” said Shanghai Electric Nuclear Power Equipment Co. (SENPEC).

“In the nuclear industry, there is an immense amount of specifications and requirements to ensure the safety and quality of the products used. This was a highly specified product, so we’re proud to have surpassed both the technical requirements and the customer’s expectations. We’re looking forward to continuing our longstanding relationship with Shanghai Electric,” said Magnus Brodin, Global Marketing and Sales Manager, Sandvik.