A new phase of construction is underway on a third-generation Chinese nuclear reactor being built in Fujian province. Designers of the overall project hope it will become a model which Chinese authorities will be able to export abroad.

A dome measuring 24 meters across is now being installed on top of the reactor chamber at the Hualong-1 nuclear power plant, which is under construction in the city of Fuqing.

Construction of the plant originally began in May of last year.

Chen Guocai, a manager of the project, says the new dome is designed to guarantee the maximum safety of the chamber.

"Now it's hemispheric in shape. It used to be oval. This dome increases the volume of the container, which is also three to four times heavier than before. This new shape guarantees the integrity and tightness of the reactor chamber. It plays a critical role in containing radioactivity. This alloy steel plate we use differs from normal steel plates. It is up to six times stronger, giving it much more resistance against earthquakes and higher pressures than normal steel plates."

Hualong-1 also uses a double containment design, with the inner layer ensuring the tightness of the reactor chamber, while the outer containment layer can deter outside impacts, including that by an airliner.

Hualong-1 is being jointly developed by the China National Nuclear Corporation and the China General Nuclear Power Group.

Its construction is part of a broader plan by Chinese authorities to export more of China's nuclear technology abroad. Hualong-1 is compliant with all safety requirements of the International Atomic Energy Agency.

Its technology is already being used in the construction of a power plant in the Pakistani city of Karachi. The Argentinian government has also agreed to build a plant using the Hualong-1 technology. British authorities are also reviewing the design for possible use.

When it comes to nuclear power plants, containing and treating the byproducts of the nuclear reaction process is a major concern. As such, experts at the Hualong-1 construction site in Fuqing are working to ensure the safety of the surrounding environment. Geng Fei is one of them.

"After the Fukushima nuclear accident in 2011, we improved our equipment. We improved the valves for our spent fuel pool-- adding monitoring systems for temperature and water levels, as well as a water supplementation system."

Geng Fei says the technology has made so many advancements that radiation within the reactor area hovers at just above zero micro-sieverts.

"What is one micro-sievert? For example, you take a plane from Beijing to Fuzhou and then return. You will get a radiation dose of 50 micro-sieverts. Or you work in Beijing for one year, you may get natural radiation of 2000 micro-sieverts. However, in our plant, if you stay here for over an hour, the radiation dose is nearly zero. "

The Hualong-1 plant in Fujian is set to be completed in 2020.