Romanian President Also Eyeing Korea's 'Secret Factory'... Doosan Enerbility, World's First Established [AI Era: Electricity is National Power]⑥

World's First Dedicated SMR Factory Established
NuScale's Spiral Heat Transfer Tube
First-Ever Production of 'Helical & Banding'
Considering Construction of New Factory to Meet Rising Demand

Inside Doosan Enerbility's Changwon headquarters nuclear factory, there is another secret factory where external access is strictly controlled. This is the so-called 'Tube Process Shop.' Even Changwon factory employees must receive separate certification to enter this area. Photography is, of course, prohibited. On the 21st of last month, guided by an employee, I entered and saw a large spiral metal tube bent in a straight line on one side placed on the central workbench. This tube is the 'Helical & Banding heat transfer tube' used in NuScale's Small Modular Reactor (SMR) from the United States.

The heat transfer tubes, which are equipment installed inside the steam generator, transfer the thermal energy generated by nuclear fission to heat water and produce steam. The steam's power then drives turbines to generate electricity. In conventional large nuclear power plants, U-shaped tubes are densely arranged inside the steam generator. In contrast, NuScale's SMR is designed so that the spiral heat transfer tubes tightly wrap around the fuel rods. This design, called Helical & Banding, is a patented technology unique to NuScale and has not yet been commercialized anywhere. Doosan Enerbility produced this spiral heat transfer tube for the first time in the world while reviewing the NuScale SMR redesign.

Doosan Enerbility is manufacturing nuclear reactor main equipment at the forging plant of its Changwon factory. Provided by Doosan Enerbility

Last April, when Klaus Iohannis, the President of Romania, visited Doosan Enerbility's Changwon factory, he also toured this facility. Romania is currently considering the introduction of NuScale's SMR. The visit was to visually confirm this essential heat transfer tube technology necessary for the commercialization of NuScale's SMR.

As we enter the era of artificial intelligence (AI), global big tech companies are rushing to invest in SMRs, anticipating a surge in power demand for data centers. SMRs are suitable as power sources for data centers because they can be built on smaller sites than large nuclear plants and offer higher safety and efficiency. Chris Wright, the U.S. Secretary of Energy under the second Trump administration, also mentioned at his confirmation hearing that SMRs should be used as an alternative to large nuclear power plants. Naturally, Doosan Enerbility has emerged as a beneficiary in the AI era.

Doosan Enerbility's nuclear factory covers 50,400 square meters (about 15,000 pyeong), equivalent to six and a half soccer fields. It consists of five bays and produces core main equipment such as reactors, steam generators, pressurizers, and coolant pumps. In March last year, with the establishment of the Tube Process Shop, it gained prestige as the world's first factory dedicated to SMRs. Doosan Enerbility's SMR Project Manager Ha Chang-hoon explained, "We are fully prepared to manufacture whenever there is an order from a customer." Doosan Enerbility is also considering building a new factory dedicated to SMRs in anticipation of increased demand.

Doosan Enerbility Changwon Plant's SMR PM, Chang Hachang, is explaining the structure of the NuScale small modular reactor (SMR) currently under production. Changwon - Photo by Kang Heejong

The production of reactor main equipment begins with casting and forging. Casting is a method of manufacturing by pouring molten metal into molds, while forging is manufacturing by hammering metal materials. On that day, entering the forging factory, a giant manipulator resembling a huge claw was holding a 230-ton ingot heated to 900 degrees Celsius, performing press work. The 17,000-ton press carefully shaped the ingot as if molding a lump of clay. This process increases density and strength.

After about three weeks of work, this ingot is reborn as a reactor head used in large nuclear power plants. For large nuclear plants, it takes about 10 to 12 months from steelmaking to delivery. For SMRs, this period can be significantly shortened. Doosan Enerbility's Baek Min-geun, head of the forging production management team, explained, "Since SMRs repeatedly produce main equipment of the same specifications, the manufacturing period can be greatly reduced."

For example, NuScale's SMR structure includes up to 12 small reactors rated at 77 megawatts (MW) each. Since the specifications are the same after manufacturing the first reactor, subsequent reactors can be produced in a shorter period. Doosan Enerbility expects, "Although the initial production cost of SMRs will be high, as supply performance increases, it will converge to a level below that of large nuclear power plants."

Interior view of the nuclear power plant at Doosan Enerbility Changwon Plant. Provided by Doosan Enerbility

The molds produced in the forging process are moved to the nuclear factory for machining. On that day, machining work for the steam generators to be installed in Shin Hanul Units 3 and 4 was in full swing at the nuclear factory. PM Ha Chang-hoon explained, "Compared to large nuclear plants, the smaller size of SMRs allows the reactor to be completed here and transported to the site using special trucks or ships." NuScale's SMR is designed with a width of 5 meters to pass through any tunnel in the United States.

A reactor manufactured by Doosan Enerbility is being transported. Provided by Doosan Enerbility

Doosan Enerbility aims to be an 'SMR foundry.' A foundry is a company specializing in production commissioned by design companies. Taiwan Semiconductor Manufacturing Company (TSMC) is a representative example. Doosan has secured main equipment supply rights not only with NuScale but also with U.S. companies X-Energy and TerraPower. It is also participating in the national project for the Innovative Small Modular Reactor (i-SMR) in Korea.

The nuclear power market has been stagnant for the past 20 years. During this period, the U.S. and Western countries lost their nuclear power know-how, expertise, and supply chains. As a result, countries capable of independently supplying third-generation nuclear power plants are limited to Korea, China, Russia, and a few others.

Korea also suffered some supply chain damage due to the nuclear phase-out policy in recent years but has relatively maintained trust in its supply chain and manufacturing technology. Doosan has manufactured and delivered 34 reactors and 124 steam generators to date. These main equipment units have been operating without issues in domestic and overseas nuclear power plants. This is the background for Doosan Enerbility's participation in numerous overseas SMR projects. PM Ha Chang-hoon said, "We expect to sign official delivery contracts within this year."