Could ‘swimming pool’ nuclear reactors help clear China’s winter smog?
Nuclear option could cut dependence on coal-powered heating in pollution-plagued northern cities, supporters say
China could flick the switch from fossil-fuel boilers to “swimming pool” nuclear reactors if an idea to help clear the country’s smog-choked northern winter skies gets the green light.
Wang Naiyan, honorary chairman of the China Nuclear Society and a lead scientist at the China Institute of Atomic Energy, said top state leaders had responded positively to the plan to replace coal and natural gas heating plants in northern China with the reactors – small, simple nuclear heating plants with “zero meltdown risk”.
Each winter, China chokes from the half a billion tonnes of coal it uses for heating – enough to power Britain for nearly three decades.
Cutting that pollution is now a central government priority and one that proponents of the reactors say the technology can help realise.
But industry specialists warn that the biggest challenge would be getting public support for the swimming pool reactors, which are in theory safe enough to swim in.
“We nuclear scientists may think it is absolutely safe, but most people may still refuse to have a reactor on their doorstep,” said Zhang Jige, associate professor at Shanghai Jiao Tong University’s school of nuclear science and technology.
Concerns have also been raised about how to store and handle the large amount of radioactive waste produced by the reactors.
The central government has commissioned Xian Jiaotong University, a nuclear research base in northwestern China’s Shaanxi province, to draw up a blueprint for a demonstration plant suitable for universal use.
The plant could be built in a major city in the region, like Baotou in Inner Mongolia, where severe pollution makes it a prime testing ground. If accepted by residents and approved by environmental regulators, a demonstration project could be up and running in less than three years, Wang said.
He added that there was strong interest in the project at the city and provincial government level, as well as from central agencies such as the Ministry of Environmental Protection and National Energy Administration (NEA).
A nuclear safety regulator at the environment ministry said he had been told about the project but could not provide any further information. The NEA did not respond to requests for comment.
Wang said that if approved, the technology could help to improve air quality for more than 700 million citizens living in 17 provinces, and boost an economy struggling to keep up growth under environmental pressures.
Each of the proposed heating plants would cost about 1.3 billion to 1.4 billion yuan (US$197 million to US$212 million) to build, a fraction of the price of a commercial nuclear power plant, he said.
How do the reactors work?
Each steel-and-concrete reactor pool measures about 10 metres in diameter and 20 metres deep, and holds up to 1,800 tonnes of water. A nuclear core is submerged in the water and can create up to 400 megawatts of heat to water to about 90 degrees Celsius for distribution through the city’s public heating network.
A single reactor can produce enough energy to heat 10 million square metres of living space within a 35km range. Two or three reactors would be enough heat a mid-sized city, though bigger metropolitan centres like Beijing would require more units.
“Together these small, simple reactors for heat generation can reach a scale many times [that of the] large, sophisticated and expensive nuclear power plants under construction or planned for electricity production,” Wang said.
“They would blow away smog, once and for all.”
In Beijing’s Fangshan and Changping districts, two swimming pool reactors built for research have been operating for decades. The one in Fangshan, built in the compound of the China Institute of Atomic Energy in the 1960s, is located about 30km south of Tiananmen Square.
The reactor is being upgraded by China National Nuclear Corporation to heat up two office buildings from early next year. Wang said the demonstration could pave way for the construction of more nuclear heating plants in Beijing’s suburbs.
He Mengchang, a professor at Beijing Normal University’s environment school, said using the pool reactors to combat smog was a new idea and “may actually work”.
Small reactors had been used in submarines or aircraft carriers. If they posed little radiation hazard to crews in confined environments, they should be safe for residential areas, he said.
“But they must undergo a strict environment assessment before construction. An important part of the evaluation process is to collect the opinions from residents,” He said.
Zhang Jige, of Shanghai Jiao Tong University, said the swimming pool reactor was one of the earliest and most conservative reactor designs and had been used in many countries.
But the technology was shelved for decades because it was not an efficient system for steam-turbine power generation.
“But now it looks like a powerful weapon against smog,” he said.
But Zhang warned that widespread construction of such reactors in or near densely populated areas could ignite street protests if the decision was made without genuine public consultation.
There were also other problems.
“The fuel of uranium-235 is also expensive and of limited supply. It will also be a challenge to store and handle the large amount of radioactive nuclear waste produced by these reactors,” Zhang said.
Getting the public on side
To encourage public support, the facility should be open to visitors from all over the country, Wang said.
“The final nod [should not be] from government officials, but the people. If our residents can come by the pool and see the crystal-clear water, it will give them direct experience of how it works, and they may want one in [their] backyard,” he said.
For this type of reactor, “meltdown risk is zero”, he said.
Meltdowns, the most kind of serious nuclear accident, occur when a chain reaction causes the uranium fuel to melt – as was the case at Three Mile Island in the United States, Chernobyl in Ukraine and Fukushima in Japan.
Last winter, Beijing choked on some of its worst air pollution in recent years. The municipal government planned to ban coal and rely almost exclusively on natural gas for heating from this winter.
But natural gas is expensive, and most other cities in northern China still relied on coal.
The mayors in these cities were caught in a dilemma, according to Wang. They were required by law to shut down factories on polluted days, and air quality was a big factor in their political career. But if the factories frequently stopped production, there would be no tax revenue, no economic growth, and no jobs.
Wang said smog had affected almost all industries in China, including the nuclear power sector.
As big factories shut down to cut pollution, their demand for electricity slumped, causing a surplus in power supply. It forced some nuclear power plants to operate at below full capacity, and made the authorities wary of approving new plants.
Wang said swimming pool reactors would create new business for mainland industry and strengthen its competence in global markets.
In non-heating seasons reactors could be used for research or as a neutron source for industrial, food or medical uses. The neutrons emitted by the reactor had been used by researchers to treat diseases such as cancer.