The crucial installation was declared a success on Jun 17 of the steel dome of the outer containment shell in the No 2 reactor building of the K2 / K3 project in Karachi, Pakistan, being built by China National Nuclear Corporation.

A CNNC spokesman said that with a diameter of 53 meters and a weight of about 366 tons, the dome was another innovative measure proposed by its engineers.

Since the construction started in 2014, the harsh environment in the country has brought great deal of challenges to the construction of the K2 / K3 project, officials said

In order to ensure the smooth construction of the Hualong project, CNNC, as the general contractor, put forward many technological innovations, including the steel outer dome.

"This is the first overall implementation of the steel dome plan for the Hualong One (HPR 1000) project," said Yang Chaodong, secretary of the Party committee and chairman of CNNC.

"This is a good demonstration of China's independent third-generation nuclear power technology and engineering construction technology," he said.

"It will set an example for future construction of the Hualong One (HPR 1000) project and will enhance the competitiveness of Chinese projects on the international stage."

The temperature in Karachi reached over 40 degrees Celsius in June.

"Demonstrating Chinese wisdom has been the first goal set by our company from the beginning," said Song Fengwei, general director of the project, with his eyes squinted under the scorching sun.

He said that in addition to political factors, the perfect integration of advanced technology, safety and efficiency makes nuclear power technology the most welcomed technology for international buyers.

The concept behind CNNC's bespoke projects -- such as this one -- is projects with high safety standards, excellent quality, a short construction period and high efficiency. Only boutique products can attract the attention of buyers, according to Song.

CNNC's construction team accurately calculated each procedure of the construction period, while taking advantage of innovation at the same time. An official said that a series of innovative outcomes had fundamentally changed the traditional progress of nuclear power plant construction -- and effectively shortened the construction period.

In October 2017, the Karachi K2 project finished the inner dome hoisting, marking the beginning of a new construction stage. During the risk assessment of the project, engineers found that the original design would not be able to meet the time requirements.

The team put forward the idea of using mainly steel to replace the original material. But there remained niggling concerns whether the idea was feasible?

Also under the spotlight were worries about whether the rigidity and weight of the steel could support the pouring concrete -- As well as whether the main crane could hoist such a large dome.

Skepticism did not hinder the pace of the engineers, however "Through continuous innovation, our team became more confident to overcome those problems," Song Fengwei said with a smile.

Facts proved that the first steel dome effectively avoided the impact on the overall containment test and significantly increased the safety factors.

"Innovation is by no means boldness. We must make adventurous assumptions while carefully verifying them." Song said.

"The project is currently going well, but there is still much to do for us."