On a coastal stretch of Hainan province, where tropical humidity meets the South China Sea, a reactor small enough to fit inside a sports stadium is nearing the finish line. If China National Nuclear Corporation holds to its reported schedule, the Linglong One reactor at the Changjiang Nuclear Power Plant will begin operations in 2026, making it the first commercial small modular reactor on land anywhere in the world.
The milestone would hand China a concrete lead in a technology race that the United States, Britain, and Canada have so far waged mostly on paper.
What Linglong One actually is
Linglong One is built on CNNC’s ACP100 platform, an integral pressurized water reactor that packages the steam generators, coolant pumps, and reactor core inside a single vessel. That compact layout is the defining feature of small modular reactor design: fewer external pipes, a smaller footprint, and passive safety systems that can cool the core without operator intervention or external power in an emergency.
The reactor’s electrical output is rated at 125 megawatts, roughly one-tenth the capacity of a conventional large reactor but enough to supply power to a small city or industrial zone. Beyond electricity, the ACP100 is designed to support district heating and seawater desalination, a combination that makes particular sense for an island province like Hainan, where grid links to the mainland carry logistical and cost constraints.
Construction officially broke ground in July 2021, according to an announcement from China’s National Nuclear Safety Administration, the regulatory body under the Ministry of Ecology and Environment. That notice, sourced to the Xinhua news agency, described Linglong One as “the world’s first commercial small modular reactor (SMR) project on land.” The regulator’s summary remains available on the NNSA’s English-language news page.
“This is a significant step for the global SMR community,” said Liu Hua, then head of the National Nuclear Safety Administration, in remarks carried by Xinhua at the time of the construction launch. The ACP100 design is also registered in the International Atomic Energy Agency’s Advanced Reactors Information System (ARIS) database, which catalogues SMR designs worldwide and provides independent technical descriptions of their specifications.
Why the timeline matters
No other land-based commercial SMR on the planet has reached this stage. The closest comparison, Russia’s Akademik Lomonosov, has been generating power since 2020, but it is a barge-mounted floating reactor serving the remote Arctic town of Pevek, not a grid-connected land installation in the conventional sense. Linglong One occupies a different category: a fixed, onshore plant feeding into a provincial power grid.
Western SMR programs remain years behind. In the United States, NuScale Power secured a Nuclear Regulatory Commission design certification in August 2020 for its 50 MWe module and received approval for a 77 MWe uprated version in January 2023, but the flagship Carbon Free Power Project in Idaho fell apart in late 2023 after projected costs nearly doubled and the utility consortium backing it withdrew. Britain’s Rolls-Royce SMR is still working through the Generic Design Assessment process, with the earliest possible operations not expected until the 2030s. Canada’s Ontario Power Generation is building a GE Hitachi BWRX-300 at the Darlington site, but that unit is not expected online before 2029 at the earliest.
Against that backdrop, a five-year construction timeline from groundbreaking to commissioning would represent a pace no Western developer has matched for a commercial SMR.
What we still do not know
The most significant gap in the public record is the absence of a confirmed, independently verifiable date for fuel loading, grid connection, or commercial handover. Industry publications including World Nuclear News have reported a target window within 2026, but CNNC has not publicly locked in a specific month or quarter. As of June 2026, no official announcement of grid synchronization has appeared on the NNSA’s regulatory portal or CNNC’s public channels. Readers should treat the “this year” framing as a reported schedule target, not a confirmed regulatory milestone.
Cost transparency is another blind spot. Large nuclear projects worldwide have a stubborn history of exceeding budgets, and SMR proponents argue that factory fabrication of modular components breaks that pattern. Yet CNNC has not released detailed financial data comparing Linglong One’s actual construction spending to its original budget. Without that information, it is hard to judge whether the project validates the economic case for small reactors or simply reflects the advantages of state-backed financing, where cost overruns are absorbed differently than in private capital markets.
Safety certification details also remain limited in the public domain. The IAEA conducted a Site and External Events Design (SEED) review mission to China’s SMR program, but comprehensive, publicly accessible safety evaluation reports of the kind produced by the U.S. NRC or the UK’s Office for Nuclear Regulation have not been published for Linglong One. International observers have questioned whether China’s domestic regulatory framework will satisfy export markets that require alignment with IAEA safety standards. If CNNC intends to sell the ACP100 abroad, the transparency of its safety case will matter as much as the engineering.
The bigger picture for nuclear energy
SMRs have been pitched for over a decade as the technology that could make nuclear power faster to build, cheaper to finance, and flexible enough to complement wind and solar on grids that need steady, low-carbon baseload generation. Linglong One is the first real-world test of that pitch at commercial scale on land.
The potential applications extend beyond electricity. Island grids, remote mining operations, desalination plants, and industrial clusters that need reliable heat and power but lack the space or demand for a full-scale 1,000-megawatt plant are all scenarios where SMR advocates see a market. Hainan’s combination of tropical climate, growing energy demand, and limited land makes it a logical proving ground.
But a single project in a single regulatory environment cannot settle the debate. Even if Linglong One enters service on schedule, its long-term value will depend on measurable outcomes: capacity factor over years of operation, unplanned outage rates, maintenance costs, and whether the modular construction approach actually delivers savings that can be replicated at other sites.
What comes next at Changjiang
The verified record confirms that a specific reactor, at a named site, built by China’s state nuclear corporation, has reached the final stretch of construction with a defined 125 MWe capacity and a design that supports multiple energy applications. That alone puts China ahead of every other country in the SMR race.
What the record does not yet contain is proof of performance. Grid connection, sustained power output, published safety data, and audited cost figures will determine whether Linglong One becomes a template for dozens of future SMRs or remains a one-off demonstration. The construction milestone is real. The operating milestone, and everything it would prove, is still ahead.
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*This article was researched with the help of AI, with human editors creating the final content.
