The Era of Small Reactors? ... 'Welding' Must Be Solved First [Tech Talk]

Obstacles to Mass Production of SMR Reactors
Currently, Each Unit Takes 2 Years to Manufacture
Restoring the Weakened Ecosystem is a Priority

There is an active movement among American big tech companies to introduce Small Modular Reactors (SMRs) as the next-generation energy source. Companies like Amazon and Microsoft (MS) have already signed memorandums of understanding (MOUs) with SMR developers, and the stock prices of related companies are reacting sensitively.

However, it is premature to assume that a nuclear power renaissance will soon unfold. While it is true that SMRs have various advantages compared to traditional nuclear power plants, and political will to revive nuclear power is strong in many countries, the most crucial 'supply chain' is not yet established. Above all, welding is currently a major bottleneck.

Weld a steel wall hundreds of millimeters thick with an error margin of just one-tenth of an inch... 'The Engineering of Reactors'

Engineer welding. Not related to any specific expression in the article. Pixabay

Whether it is a large nuclear power plant or an SMR, the most important component is ultimately the reactor. The principle of nuclear energy is that the reactor, heated by nuclear fission reactions, boils water to produce steam, which then drives turbines to generate electricity. However, the reactor is an extremely difficult component to manufacture.

According to a report released by the World Nuclear Association in 2021, the current standard reactor for nuclear power plants, the 'AP1000,' typically takes about two years from order to final assembly. It also requires regular, precise inspections over a period of more than ten years. This means that reactors have always been far from mass-produced components.

A 1400MW-class reactor of Doosan Heavy Industries & Construction. Modern nuclear power plant reactors are components boasting hundreds of tons in weight and enormous volume. Photo by Yonhap News Agency

Why is this the case? Reactors are solid objects designed to prevent the leakage of dangerous radiation. They weigh between 500 and 600 tons (t), have steel walls several hundred millimeters thick, and require meticulous cladding work on the surface even after manufacturing.

Currently, there are only a handful of ultra-large hydraulic presses worldwide capable of smelting steel ingots weighing hundreds of tons, which are the core materials for AP1000-class reactors. But the truly challenging task is welding. The joints of each component that make up the reactor must be welded without even the slightest gap or metal deterioration, making it a very demanding and labor-intensive process.

Of course, SMRs are much smaller than AP1000 reactors, so manufacturing time will be somewhat reduced. However, with current technology, it is still difficult to mass-produce reactors in a factory-like manner.

New technologies are being attempted... but still in the testing phase

A new concept electron beam welder that surrounds the beam emission path with a vacuum module to maintain the electron beam in its pure form. Cambridge Vacuum YouTube

Recently, an innovative technology in the field of reactor welding has been gaining attention. Developed by a company called 'Cambridge Vacuum,' the so-called 'Electron Beam Welding' (EBW) method uses an electron beam that penetrates much thicker metal than conventional lasers and welds quickly with less risk of metal deterioration.

However, to maintain the electron beam uniformly and purely, it must operate in a vacuum space free of particles. Since it requires an outrageously expensive vacuum clean room built to reactor specifications, commercialization was previously considered nearly impossible.

Cambridge Vacuum solved this problem by connecting a modular clean room together with the electron beam device instead of placing the electron beam device inside a vacuum clean room.

The electron beam created in this way is mounted on an industrial robot arm that can move along multiple axes, enabling rapid welding of even the thickest and largest reactor components. Currently, this technology is being tested in collaboration with 'Sheffield Forgemaster,' a UK-based supplier of key reactor components, to gauge the feasibility of mass-producing SMR parts.

If the welding issue is resolved, it could shorten the entire reactor manufacturing process by several months. This would reduce order queues and strengthen the SMR-related supply chain. However, many other issues, including cladding, remain, and it will be difficult to usher in the SMR era without resolving these supply chain bottlenecks.

Restoring the weakened nuclear power ecosystem after the Fukushima disaster is a priority

Fukushima Daiichi Nuclear Power Plant, Japan. Photo by Yonhap News

After the Fukushima nuclear power plant accident in 2011, the global nuclear power market cooled down. Not only in Korea but also in many leading nuclear power countries, component supply companies closed or merged with others. The number of skilled engineers and technicians also decreased. In a shrunken ecosystem, it is impossible to suddenly mass-produce new technologies.

The positive aspect is that the political will of governments worldwide to restore the past nuclear power supply chains and ecosystems appears firm. In the United States, the Biden administration announced a roadmap in mid-last month to triple the country's nuclear power generation capacity by 2050, and this plan is likely to be continued by the next Trump administration, which is also positive about nuclear power.

In the UK, to smoothly mass-produce SMR parts, the government is supporting the purchase of a few ultra-large presses weighing 13,000 to 15,000 tons with public funds. Traditional 'nuclear power powerhouse' France is accelerating its existing nuclear power policies.

South Korea's nuclear power industry seems to be at a crossroads once again. The government initially allocated about 214 billion won in total for nuclear power-related budgets, including 150 billion won for ecosystem financial support and 32.9 billion won for innovative i-SMR technology R&D projects. However, following the declaration of martial law on the 3rd and the ensuing 'impeachment crisis,' these funds are at risk of being completely cut.

To secure a market share in the SMR sector based on the nuclear power technology we have honed so far, reinvestment to restore the weakened nuclear power ecosystem is urgently needed. With the unprecedented crisis effectively paralyzing national governance, attention is focused on whether a bipartisan decision for future growth engines will be possible.