China has begun operations of the world’s first fourth-generation nuclear reactor that uses gas for cooling unlike conventional power plants that use pressurised water.

The power plant built in China’s Shandong province generates power from two high-temperature reactors that are cooled by gas rather than water, state news agency Xinhua reported on Wednesday.

Nuclear fission reactors typically generate power by breaking atoms and using the energy released to produce steam that runs turbines.

The steam is then cooled by water in a condenser circuit with the hot water then going to a cooling tower.

Currently water-cooled reactors account for over 95 per cent of all operating civilian power reactors globally while gas cooled ones make up about three per cent worldwide.

Interest in gas cooled reactors is increasing globally as these can provide efficient and cost effective electricity.

Such small modular reactors can also produce high-temperature process heat for industrial applications such as hydrogen production, seawater desalination, and district heating, according to the International Atomic Energy Agency (IAEA).

The reactor in Shidao Bay, China is the world’s first gas-cooled nuclear power plant built for commercial demonstration.

It is cooled by helium and can reach high temperatures of up to 750 degrees Celsius.

Construction of the plant started in 2012 and its first reactor was connected to the country’s power grid in 2021, AFP reported.

Such reactors, experts say, can also play a significant role in helping countries with energy transition due to their compact architecture and modular design reducing construction time and costs.

Over 80 SMR projects are currently under development across 18 countries, according to the IAEA.

China has already sought to become a global leader in nuclear power generation with the country planning to make these types of power plants account for 10 per cent of the its electricity generation by 2035.

The latest power plant launch also signifies China’s attempt to move away from coal-fired power plants and reduce its dependence on foreign technologies amid growing tensions with Western countries.

Impressive Milestones Achieved on Chinese Advanced Nuclear Power Projects.

China National Nuclear Corp. (CNNC) announced on Dec. 6 that China’s independently developed high-temperature gas-cooled modular pebble bed (HTR-PM) reactor demonstrator had commenced commercial operation. The HTR-PM project was constructed at a site in Rongcheng, Shandong Province (Figure 1), roughly midway between Beijing and Shanghai in eastern China. Touted as “the world’s first commercially operational modular nuclear power plant with fourth-generation nuclear technology,” the achievement marks an important milestone, transitioning the technology from experiments to the commercial market. [caption id="attachment_212395" align="aligncenter" width="600"]

1. Built on a site near Shidao Bay, also known as Shidaowan, the HTR-PM is the world’s first fourth-generation nuclear design to enter commercial operation. Courtesy: CNNC[/caption] Construction of the pioneering project began in December 2012, led by China Huaneng (which holds a 47.5% stake in the demonstration), along with CNNC subsidiary China Nuclear Engineering Corp. (CNEC, 32.5%), and Tsinghua University’s Institute of Nuclear and New Energy Technology (INET, 20%). Chinergy, a joint venture between Tsinghua and CNEC, served as the engineering, procurement, and construction contractor for the nuclear island. The HTR-PM features two small reactors, each with a capacity of 250 MWth. The reactors use helium as the coolant and graphite as the moderator. Each reactor is loaded (Figure 2) with more than 400,000 spherical fuel elements, or pebbles, each 60 millimeters in diameter, which is roughly the size of a tennis ball. Each pebble contains about seven grams of uranium fuel enriched to 8.5%. [caption id="attachment_160957" align="aligncenter" width="600"]

2. Fuel loading at the Shidaowan HTR-PM in China began in the spring of 2021. It involved putting 870,000 spherical TRISO fuel elements into the two small reactors that will drive a single 210-MWe turbine. Courtesy: CNNC[/caption] Heat from the reactor produces steam in a steam generator. Tsinghua has reported helium temperatures at the reactor core inlet run about 250C, while outlet temperatures reach about 750C. Steam at 13.25 Megapascal (MPa) and 567C is produced at the steam generator outlet. The steam is used to drive a single steam turbine connected to a 210-MWe generator. The demonstration project was first connected to the grid on Dec. 20, 2021. Significant testing has been done since that time to validate operation and demonstrate acceptability. CNNC said the HTR-PM design has broad applications in various fields including power generation and combined heat and power. It noted advantages include high safety, power generation efficiency, and environmental adaptability. Tsinghua has said more than 30 years of continuous research, conducted by hundreds of Tsinghua scientists, has gone into the project. Developers stepped from the basic research of key technologies, to a 10-MW experimental reactor (HTR-10) built at an INET site, and finally to the demonstration project that is now in commercial operation at Shidaowan. Notably, Tsinghua said 93.4% of the equipment used in the final HTR-PM project was manufactured domestically.

Linglong One SMR Milestone

Meanwhile, China also is leading the nuclear industry forward with construction of the world’s first multipurpose small modular reactor (SMR) demonstration project, known as Linglong One. The unit is sited in southern China on the island of Hainan. In November, CNNC announced the top head of the steel containment vessel for the unit was hoisted into place, signaling commencement of the peak phase of internal installation. The Linglong One project began construction at the Changjiang Nuclear Power Plant on July 13, 2021. Linglong One, also known as the ACP100 design, is a multipurpose pressurized water reactor design developed by CNNC following more than 10 years of independent research and development. CNNC has called it “another significant achievement of independent innovation after Hualong One, CNNC’s third-generation nuclear power technology.” In 2016, the Linglong One design became the first SMR to pass a safety review by the International Atomic Energy Agency. Each Linglong One unit has a generating capacity of 125 MW. The demonstration project is wholly owned by CNNC’s China National Nuclear Power. CNNC has said the design and construction of Linglong One are revolutionary and groundbreaking. Modular construction is its most prominent feature. On Aug. 10 this year, the core module of the Linglong One reactor was lifted and placed in the nuclear island (Figure 3). The pressure vessel, evaporator, and other key equipment were installed in one step. Through standardized design, single module production, and mass production, the construction period is shortened and costs reduced, while improving safety, the company said. The small size and simplified system make the SMR convenient for transportation and operation. [caption id="attachment_212396" align="aligncenter" width="600"]

3. The Linglong One core module is shown here being lifted for installation into the plant’s containment building. Courtesy: CNNC[/caption] In addition to generating electricity, CNNC said the Linglong One can also be used for seawater desalination, and heating or cooling, among other useful purposes. The company envisions it serving as self-contained energy sources for parks, islands, mining areas, and high-energy-consuming enterprises. —Aaron Larson is POWER’s executive editor (@POWERmagazine). POWER Senior Associate

Palisades owners pitch adding two small modular reactors.

 The company that owns the Palisades power plant in Van Buren County is proposing the addition of two small nuclear reactors at the site as it also plans to bring the original plant back online.

Holtec International says the new reactors would double the amount of electricity that could be produced at Palisades but critics are concerned about safety and the nuclear waste.

$150M in state budget to reopen Palisades

If Holtec’s proposal becomes reality, it would be the first time the company’s modular reactor design would be used.

“Small modular reactors are the next stage of nuclear technology here in the United States and around the world, Nick Culp, the senior manager of government affairs and communications with Holtec, said. “So our design is a small pressurized water reactor similar to what operates at many plants in the United States today but it is of a simplified and smaller version and also modular, which means that it’s factory-built and deployable to virtually anywhere in the world.”

Kevin Kamps with Beyond Nuclear, an advocacy group opposed to the plan, pointed out that Holtec has never operated a nuclear power plant and was hired to decommission the plant, not restart it.

“I call it radioactive Russian roulette on the Lake Michigan shoreline,” Kamps said. “All of the high-level radioactive waste ever generated at Palisades since 1971 is still on site. About two thirds of it is in the indoor wet storage pool, which is not good; it is packed to the gills. A storage pool fire could take out a large section of the United States.”

The group said the small reactors will produce more waste than the existing reactor and it is also concerned about the other way the nuclear waste is stored.

“There’s the dry cask storage, which has been very problematic. This is the outdoor silos of concrete and steel that contain the overflow storage for high-level waste on the beach of Lake Michigan, at most 150 yards from the water,” Kamps said.

The plant south of South Haven stopped producing electricity in May of last year. The state has approved $150 million for its restart and Holtec is working to secure federal loans.

“If we’re going to hit in a very serious way any climate targets, you need nuclear base load generation as part of that mix to make sure that we have around-the-clock energy for our households and companies,” Culp said.

Aditi Verma, an assistant professor of nuclear engineering with the University of Michigan, said successfully restarting the refurbished plant will depend on its condition, the requirements from federal regulators and future electricity costs.

“There are certainly plants that have operated for up to 60 years or even more and there are others that are licensed for up to 80 years,” Verma said.

She said the amount of additional waste produced using the small reactors would be small compared with waste produced from other forms of electricity.

Companies are designing small reactors because they are less expensive to build, simpler systems, can be more easily placed in an areas with transmission lines and can be built in a factory setting. Large reactors are more economically efficient overtime.

“There are just very different pros and cons associated with the two kinds of systems,” Verma said.

Holtec is awaiting approval from the Nuclear Regulatory Commission to move forward and says it has the expertise to run the plant.

“The U.S. nuclear industry is one of the most heavily regulated and safest industries in the country, so the spent material that is produced through the nuclear fission process is safely stored here on site. Holtec International, our company, is actually the domestic and global leader in dry cask storage,” Culp said.

The company says it expects the existing reactor to be refurbished by the end of 2025 and to start building the small reactors by 2030.